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The prototypes for the following functions lie in gnutls/gnutls.h.
session: is a gnutls_session_t type.
This function will return the last alert number received. This
function should be called when GNUTLS_E_WARNING_ALERT_RECEIVED or
GNUTLS_E_FATAL_ALERT_RECEIVED errors are returned by a gnutls
function. The peer may send alerts if he encounters an error.
If no alert has been received the returned value is undefined.
Returns: the last alert received, a
gnutls_alert_description_t value.
alert: is an alert number.
This function will return a string that describes the given alert
number, or NULL . See gnutls_alert_get() .
Returns: string corresponding to gnutls_alert_description_t value.
alert: is an alert number.
This function will return a string of the name of the alert.
Returns: string corresponding to gnutls_alert_description_t value.
Since: 3.0
session: is a gnutls_session_t type.
level: is the level of the alert
desc: is the alert description
This function will send an alert to the peer in order to inform him of something important (eg. his Certificate could not be verified). If the alert level is Fatal then the peer is expected to close the connection, otherwise he may ignore the alert and continue.
The error code of the underlying record send function will be
returned, so you may also receive GNUTLS_E_INTERRUPTED or
GNUTLS_E_AGAIN as well.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type.
err: is an error code returned by another GnuTLS function
Sends an alert to the peer depending on the error code returned by
a gnutls function. This function will call gnutls_error_to_alert()
to determine the appropriate alert to send.
This function may also return GNUTLS_E_AGAIN , or
GNUTLS_E_INTERRUPTED .
This function historically was always sending an alert to the
peer, even if err was inappropriate to respond with an alert
(e.g., GNUTLS_E_SUCCESS ). Since 3.6.6 this function returns
success without transmitting any data on error codes that
should not result to an alert.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is gnutls_session_t type
func: is the function to be called
This function will set a callback to be called when an alert message is being sent.
Since: 3.7.0
session: is a gnutls_session_t type.
protocol: will hold the protocol name
This function allows you to get the negotiated protocol name. The returned protocol should be treated as opaque, constant value and only valid during the session life.
The selected protocol is the first supported by the list sent by the client.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.2.0
session: is a gnutls_session_t type.
protocols: is the protocol names to add.
protocols_size: the number of protocols to add.
flags: zero or a sequence of gnutls_alpn_flags_t
This function is to be used by both clients and servers, to declare the supported ALPN protocols, which are used during negotiation with peer.
See gnutls_alpn_flags_t description for the documentation of available
flags.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.2.0
sc: is a pointer to a gnutls_anon_client_credentials_t type.
Allocate a gnutls_anon_client_credentials_t structure.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
sc: is a pointer to a gnutls_anon_server_credentials_t type.
Allocate a gnutls_anon_server_credentials_t structure.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
sc: is a gnutls_anon_client_credentials_t type.
Free a gnutls_anon_client_credentials_t structure.
sc: is a gnutls_anon_server_credentials_t type.
Free a gnutls_anon_server_credentials_t structure.
res: is a gnutls_anon_server_credentials_t type
func: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for anonymous authentication.
The callback should return GNUTLS_E_SUCCESS (0) on success.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
res: is a gnutls_anon_server_credentials_t type
dh_params: The Diffie-Hellman parameters.
This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Anonymous Diffie-Hellman cipher suites.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
res: is a gnutls_anon_server_credentials_t type
sec_param: is an option of the gnutls_sec_param_t enumeration
This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Anonymous Diffie-Hellman cipher suites and will be selected from the FFDHE set of RFC7919 according to the security level provided.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.5.6
res: is a gnutls_certificate_credentials_t type
func: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman parameters for anonymous authentication. The
callback should return GNUTLS_E_SUCCESS (0) on success.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
anti_replay: is a gnutls_anti_replay type
This function will deinitialize all resources occupied by the given anti-replay context.
Since: 3.6.5
session: is a gnutls_session_t type.
anti_replay: is a gnutls_anti_replay_t type.
Request that the server should use anti-replay mechanism.
Since: 3.6.5
anti_replay: is a pointer to gnutls_anti_replay_t type
This function will allocate and initialize the anti_replay context
to be usable for detect replay attacks. The context can then be
attached to a gnutls_session_t with
gnutls_anti_replay_enable() .
Returns: Zero or a negative error code on error.
Since: 3.6.5
anti_replay: is a gnutls_anti_replay_t type.
add_func: is the function.
Sets the function that will be used to store an entry if it is not
already present in the resumed sessions database. This function returns 0
if the entry is successfully stored, and a negative error code
otherwise. In particular, if the entry is found in the database,
it returns GNUTLS_E_DB_ENTRY_EXISTS .
The arguments to the add_func are:
- ptr : the pointer set with gnutls_anti_replay_set_ptr()
- exp_time : the expiration time of the entry
- key : a pointer to the key
- data : a pointer to data to store
The data set by this function can be examined using
gnutls_db_check_entry_expire_time() and gnutls_db_check_entry_time() .
Since: 3.6.5
anti_replay: is a gnutls_anti_replay_t type.
ptr: is the pointer
Sets the pointer that will be provided to db add function as the first argument.
anti_replay: is a gnutls_anti_replay_t type.
window: is the time window recording ClientHello, in milliseconds
Sets the time window used for ClientHello recording. In order to protect against replay attacks, the server records ClientHello messages within this time period from the last update, and considers it a replay when a ClientHello outside of the period; if a ClientHello arrives within this period, the server checks the database and detects duplicates.
For the details of the algorithm, see RFC 8446, section 8.2.
Since: 3.6.5
session: is a gnutls_session_t type.
Returns the type of credentials that were used for client authentication. The returned information is to be used to distinguish the function used to access authentication data.
Note that on resumed sessions, this function returns the schema used in the original session authentication.
Returns: The type of credentials for the client authentication
schema, a gnutls_credentials_type_t type.
session: is a gnutls_session_t type.
Returns type of credentials for the current authentication schema. The returned information is to be used to distinguish the function used to access authentication data.
Eg. for CERTIFICATE ciphersuites (key exchange algorithms:
GNUTLS_KX_RSA , GNUTLS_KX_DHE_RSA ), the same function are to be
used to access the authentication data.
Note that on resumed sessions, this function returns the schema used in the original session authentication.
Returns: The type of credentials for the current authentication
schema, a gnutls_credentials_type_t type.
session: is a gnutls_session_t type.
Returns the type of credentials that were used for server authentication. The returned information is to be used to distinguish the function used to access authentication data.
Note that on resumed sessions, this function returns the schema used in the original session authentication.
Returns: The type of credentials for the server authentication
schema, a gnutls_credentials_type_t type.
base64: contains the encoded data
result: the location of decoded data
This function will decode the given base64 encoded data. The decoded data will be allocated, and stored into result.
You should use gnutls_free() to free the returned data.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
data: contains the raw data
result: will hold the newly allocated encoded data
This function will convert the given data to printable data, using the base64 encoding. This function will allocate the required memory to hold the encoded data.
You should use gnutls_free() to free the returned data.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
dest: the buffer to append to
data: the data
data_size: the size of data
Appends the provided data to the destination buffer.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
session: is a gnutls_session_t type.
how: is an integer
Terminates the current TLS/SSL connection. The connection should
have been initiated using gnutls_handshake() . how should be one
of GNUTLS_SHUT_RDWR , GNUTLS_SHUT_WR .
In case of GNUTLS_SHUT_RDWR the TLS session gets
terminated and further receives and sends will be disallowed. If
the return value is zero you may continue using the underlying
transport layer. GNUTLS_SHUT_RDWR sends an alert containing a close
request and waits for the peer to reply with the same message.
In case of GNUTLS_SHUT_WR the TLS session gets terminated
and further sends will be disallowed. In order to reuse the
connection you should wait for an EOF from the peer.
GNUTLS_SHUT_WR sends an alert containing a close request.
Note that not all implementations will properly terminate a TLS connection. Some of them, usually for performance reasons, will terminate only the underlying transport layer, and thus not distinguishing between a malicious party prematurely terminating the connection and normal termination.
This function may also return GNUTLS_E_AGAIN or
GNUTLS_E_INTERRUPTED ; cf. gnutls_record_get_direction() .
Returns: GNUTLS_E_SUCCESS on success, or an error code, see
function documentation for entire semantics.
session: is a gnutls session
This function will return the peer’s certificate activation time.
Returns: (time_t)-1 on error.
Deprecated: gnutls_certificate_verify_peers2() now verifies activation times.
res: is a pointer to a gnutls_certificate_credentials_t type.
Allocate a gnutls_certificate_credentials_t structure.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
session: is a gnutls session
Get whether client certificate was requested on the last handshake or not.
Returns: 0 if the peer (server) did not request client authentication or 1 otherwise.
session: is a gnutls session
This function will return the peer’s certificate expiration time.
Returns: (time_t)-1 on error.
Deprecated: gnutls_certificate_verify_peers2() now verifies expiration times.
sc: is a gnutls_certificate_credentials_t type.
This function will delete all the CA name in the given credentials. Clients may call this to save some memory since in client side the CA names are not used. Servers might want to use this function if a large list of trusted CAs is present and sending the names of it would just consume bandwidth without providing information to client.
CA names are used by servers to advertise the CAs they support to clients.
sc: is a gnutls_certificate_credentials_t type.
This function was operational on very early versions of gnutls. Due to internal refactorings and the fact that this was hardly ever used, it is currently a no-op.
sc: is a gnutls_certificate_credentials_t type.
Free a gnutls_certificate_credentials_t structure.
This function does not free any temporary parameters associated with this structure (ie RSA and DH parameters are not freed by this function).
sc: is a gnutls_certificate_credentials_t type.
This function will delete all the CRLs associated with the given credentials.
sc: is a gnutls_certificate_credentials_t type.
This function will delete all the keys and the certificates associated with the given credentials. This function must not be called when a TLS negotiation that uses the credentials is in progress.
sc: is a gnutls_certificate_credentials_t type.
idx1: the index of the certificate chain if multiple are present
idx2: the index of the certificate in the chain. Zero gives the server’s certificate.
cert: Will hold the DER encoded certificate.
This function will return the DER encoded certificate of the
server or any other certificate on its certificate chain (based on idx2 ).
The returned data should be treated as constant and only accessible during the lifetime
of sc . The idx1 matches the value gnutls_certificate_set_x509_key() and friends
functions.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value. In case the indexes are out of bounds GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
is returned.
Since: 3.2.5
sc: is a gnutls_certificate_credentials_t type.
cert: is the certificate to find issuer for
issuer: Will hold the issuer if any. Should be treated as constant.
flags: Use zero or GNUTLS_TL_GET_COPY
This function will return the issuer of a given certificate.
If the flag GNUTLS_TL_GET_COPY is specified a copy of the issuer
will be returned which must be freed using gnutls_x509_crt_deinit() .
In that case the provided issuer must not be initialized.
As with gnutls_x509_trust_list_get_issuer() this function requires
the GNUTLS_TL_GET_COPY flag in order to operate with PKCS11 trust
lists in a thread-safe way.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.0
sc: is a credentials structure.
idx: is a certificate chain index as returned by gnutls_certificate_set_key() and friends
oidx: is an OCSP response index
flags: should be zero
This function returns the validity of the loaded OCSP responses, to provide information on when to reload/refresh them.
Note that the credentials structure should be read-only when in use, thus when reloading, either the credentials structure must not be in use by any sessions, or a new credentials structure should be allocated for new sessions.
When oidx is (-1) then the minimum refresh time for all responses
is returned. Otherwise the index specifies the response corresponding
to the odix certificate in the certificate chain.
Returns: On success, the expiration time of the OCSP response. Otherwise (time_t)(-1) on error, or (time_t)-2 on out of bounds.
Since: 3.6.3
session: is a gnutls session
Gets the certificate as sent to the peer in the last handshake. The certificate is in raw (DER) format. No certificate list is being returned. Only the first certificate.
This function returns the certificate that was sent in the current
handshake. In subsequent resumed sessions this function will return
NULL . That differs from gnutls_certificate_get_peers() which always
returns the peer’s certificate used in the original session.
Returns: a pointer to a gnutls_datum_t containing our
certificate, or NULL in case of an error or if no certificate
was used.
session: is a gnutls session
list_size: is the length of the certificate list (may be NULL )
Get the peer’s raw certificate (chain) as sent by the peer. These certificates are in raw format (DER encoded for X.509). In case of a X.509 then a certificate list may be present. The list is provided as sent by the server; the server must send as first certificate in the list its own certificate, following the issuer’s certificate, then the issuer’s issuer etc. However, there are servers which violate this principle and thus on certain occasions this may be an unsorted list.
In resumed sessions, this function will return the peer’s certificate list as used in the first/original session.
Returns: a pointer to a gnutls_datum_t containing the peer’s
certificates, or NULL in case of an error or if no certificate
was used.
session: is a gnutls session
id: will contain the ID
This function is no-op.
Returns: GNUTLS_E_UNIMPLEMENTED_FEATURE .
Since: 3.1.3
res: is a gnutls_certificate_credentials_t type
Returns the verification flags set with
gnutls_certificate_set_verify_flags() .
Returns: The certificate verification flags used by res .
Since: 3.4.0
res: is a gnutls_certificate_credentials_t type.
index: The index of the certificate list to obtain.
crt_list: Where to store the certificate list.
crt_list_size: Will hold the number of certificates.
Obtains a X.509 certificate list that has been stored in res with one of
gnutls_certificate_set_x509_key() , gnutls_certificate_set_key() ,
gnutls_certificate_set_x509_key_file() ,
gnutls_certificate_set_x509_key_file2() ,
gnutls_certificate_set_x509_key_mem() , or
gnutls_certificate_set_x509_key_mem2() . Each certificate in the returned
certificate list must be deallocated with gnutls_x509_crt_deinit() , and the
list itself must be freed with gnutls_free() .
The index matches the return value of gnutls_certificate_set_x509_key() and friends
functions, when the GNUTLS_CERTIFICATE_API_V2 flag is set.
If there is no certificate with the given index,
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned. If the certificate
with the given index is not a X.509 certificate, GNUTLS_E_INVALID_REQUEST
is returned. The returned certificates must be deinitialized after
use, and the crt_list pointer must be freed using gnutls_free() .
Returns: GNUTLS_E_SUCCESS (0) on success, or a negative error code.
Since: 3.4.0
res: is a gnutls_certificate_credentials_t type.
index: The index of the key to obtain.
key: Location to store the key.
Obtains a X.509 private key that has been stored in res with one of
gnutls_certificate_set_x509_key() , gnutls_certificate_set_key() ,
gnutls_certificate_set_x509_key_file() ,
gnutls_certificate_set_x509_key_file2() ,
gnutls_certificate_set_x509_key_mem() , or
gnutls_certificate_set_x509_key_mem2() . The returned key must be deallocated
with gnutls_x509_privkey_deinit() when no longer needed.
The index matches the return value of gnutls_certificate_set_x509_key() and friends
functions, when the GNUTLS_CERTIFICATE_API_V2 flag is set.
If there is no key with the given index,
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned. If the key with the
given index is not a X.509 key, GNUTLS_E_INVALID_REQUEST is returned.
Returns: GNUTLS_E_SUCCESS (0) on success, or a negative error code.
Since: 3.4.0
session: a gnutls_session_t type.
status: is 0 or 1
If status is non zero, this function will order gnutls not to send the rdnSequence in the certificate request message. That is the server will not advertise its trusted CAs to the peer. If status is zero then the default behaviour will take effect, which is to advertise the server’s trusted CAs.
This function has no effect in clients, and in authentication methods other than certificate with X.509 certificates.
session: is a gnutls_session_t type.
req: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE, GNUTLS_CERT_IGNORE
This function specifies if we (in case of a server) are going to
send a certificate request message to the client. If req is
GNUTLS_CERT_REQUIRE then the server will return the GNUTLS_E_NO_CERTIFICATE_FOUND
error if the peer does not provide a certificate. If you do not call this
function then the client will not be asked to send a certificate. Invoking
the function with req GNUTLS_CERT_IGNORE has the same effect.
res: is a gnutls_certificate_credentials_t type
dh_params: the Diffie-Hellman parameters.
This function will set the Diffie-Hellman parameters for a certificate server to use. These parameters will be used in Ephemeral Diffie-Hellman cipher suites. Note that only a pointer to the parameters are stored in the certificate handle, so you must not deallocate the parameters before the certificate is deallocated.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
res: is a gnutls_certificate_credentials_t type
flags: are the flags of gnutls_certificate_flags type
This function will set flags to tweak the operation of
the credentials structure. See the gnutls_certificate_flags enumerations
for more information on the available flags.
Since: 3.4.7
res: is a gnutls_certificate_credentials_t type
sec_param: is an option of the gnutls_sec_param_t enumeration
This function will set the Diffie-Hellman parameters for a certificate server to use. These parameters will be used in Ephemeral Diffie-Hellman cipher suites and will be selected from the FFDHE set of RFC7919 according to the security level provided.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.5.6
sc: is a credentials structure.
response_file: a filename of the OCSP response
idx: is a certificate index as returned by gnutls_certificate_set_key() and friends
This function loads the provided OCSP response. It will be
sent to the client if requests an OCSP certificate status for
the certificate chain specified by idx .
Note: the ability to set multiple OCSP responses per credential
structure via the index idx was added in version 3.5.6. To keep
backwards compatibility, it requires using gnutls_certificate_set_flags()
with the GNUTLS_CERTIFICATE_API_V2 flag to make the set certificate
functions return an index usable by this function.
This function can be called multiple times since GnuTLS 3.6.3
when multiple responses which apply to the chain are available.
If the response provided does not match any certificates present
in the chain, the code GNUTLS_E_OCSP_MISMATCH_WITH_CERTS is returned.
To revert to the previous behavior set the flag GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK
in the certificate credentials structure. In that case, only the
end-certificate’s OCSP response can be set.
If the response is already expired at the time of loading the code
GNUTLS_E_EXPIRED is returned.
To revert to the previous behavior of this function which does not return
any errors, set the flag GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.1.3
sc: is a credentials structure.
response_file: a filename of the OCSP response
idx: is a certificate index as returned by gnutls_certificate_set_key() and friends
fmt: is PEM or DER
This function loads the OCSP responses to be sent to the
peer for the certificate chain specified by idx . When fmt is
set to PEM, multiple responses can be loaded.
This function must be called after setting any certificates, and
cannot be used for certificates that are provided via a callback –
that is when gnutls_certificate_set_retrieve_function() is used. In
that case consider using gnutls_certificate_set_retrieve_function3() .
This function can be called multiple times when multiple responses
applicable to the certificate chain are available.
If the response provided does not match any certificates present
in the chain, the code GNUTLS_E_OCSP_MISMATCH_WITH_CERTS is returned.
If the response is already expired at the time of loading the code
GNUTLS_E_EXPIRED is returned.
Returns: On success, the number of loaded responses is returned, otherwise a negative error code.
Since: 3.1.3
sc: is a gnutls_certificate_credentials_t type.
ocsp_func: function pointer to OCSP status request callback.
ptr: opaque pointer passed to callback function
This function is to be used by server to register a callback to handle OCSP status requests from the client. The callback will be invoked if the client supplied a status-request OCSP extension. The callback function prototype is:
typedef int (*gnutls_status_request_ocsp_func) (gnutls_session_t session, void *ptr, gnutls_datum_t *ocsp_response);
The callback will be invoked if the client requests an OCSP certificate
status. The callback may return GNUTLS_E_NO_CERTIFICATE_STATUS , if
there is no recent OCSP response. If the callback returns GNUTLS_E_SUCCESS ,
it is expected to have the ocsp_response field set with a valid (DER-encoded)
OCSP response. The response must be a value allocated using gnutls_malloc() ,
and will be deinitialized by the caller.
It is possible to set a specific callback for each provided certificate
using gnutls_certificate_set_ocsp_status_request_function2() .
Since: 3.1.3
sc: is a gnutls_certificate_credentials_t type.
idx: is a certificate index as returned by gnutls_certificate_set_key() and friends
ocsp_func: function pointer to OCSP status request callback.
ptr: opaque pointer passed to callback function
This function is to be used by server to register a callback to provide OCSP status requests that correspond to the indexed certificate chain from the client. The callback will be invoked if the client supplied a status-request OCSP extension.
The callback function prototype is:
typedef int (*gnutls_status_request_ocsp_func) (gnutls_session_t session, void *ptr, gnutls_datum_t *ocsp_response);
The callback will be invoked if the client requests an OCSP certificate
status. The callback may return GNUTLS_E_NO_CERTIFICATE_STATUS , if
there is no recent OCSP response. If the callback returns GNUTLS_E_SUCCESS ,
it is expected to have the ocsp_response field set with a valid (DER-encoded)
OCSP response. The response must be a value allocated using gnutls_malloc() ,
and will be deinitialized by the caller.
Note: the ability to set multiple OCSP responses per credential
structure via the index idx was added in version 3.5.6. To keep
backwards compatibility, it requires using gnutls_certificate_set_flags()
with the GNUTLS_CERTIFICATE_API_V2 flag to make the set certificate
functions return an index usable by this function.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.5.5
sc: is a credentials structure.
resp_data: a memory buffer holding an OCSP response
idx: is a certificate index as returned by gnutls_certificate_set_key() and friends
fmt: is PEM or DER
This function sets the OCSP responses to be sent to the
peer for the certificate chain specified by idx . When fmt is set
to PEM, multiple responses can be loaded.
Note: the ability to set multiple OCSP responses per credential
structure via the index idx was added in version 3.5.6. To keep
backwards compatibility, it requires using gnutls_certificate_set_flags()
with the GNUTLS_CERTIFICATE_API_V2 flag to make the set certificate
functions return an index usable by this function.
This function must be called after setting any certificates, and
cannot be used for certificates that are provided via a callback –
that is when gnutls_certificate_set_retrieve_function() is used.
This function can be called multiple times when multiple responses which
apply to the certificate chain are available.
If the response provided does not match any certificates present
in the chain, the code GNUTLS_E_OCSP_MISMATCH_WITH_CERTS is returned.
If the response is already expired at the time of loading the code
GNUTLS_E_EXPIRED is returned.
Returns: On success, the number of loaded responses is returned, otherwise a negative error code.
Since: 3.6.3
res: is a gnutls_certificate_credentials_t type
func: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for certificate
authentication. The callback should return GNUTLS_E_SUCCESS (0) on success.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
cred: is a gnutls_certificate_credentials_t type.
fn: A PIN callback
userdata: Data to be passed in the callback
This function will set a callback function to be used when required to access a protected object. This function overrides any other global PIN functions.
Note that this function must be called right after initialization to have effect.
Since: 3.1.0
cred: is a gnutls_certificate_credentials_t type.
rawpkfile: contains a raw public key in PKIX.SubjectPublicKeyInfo format.
privkeyfile: contains a file path to a private key.
format: encoding of the keys. DER or PEM.
pass: an optional password to unlock the private key privkeyfile.
key_usage: an ORed sequence of GNUTLS_KEY_ * flags.
names: is an array of DNS names belonging to the public-key (NULL if none).
names_length: holds the length of the names list.
privkey_flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t .
These apply to the private key pkey.
pkcs11_flags: one of gnutls_pkcs11_obj_flags. These apply to URLs.
This function sets a public/private keypair read from file in the
gnutls_certificate_credentials_t type to be used for authentication
and/or encryption. spki and privkey should match otherwise set
signatures cannot be validated. In case of no match this function
returns GNUTLS_E_CERTIFICATE_KEY_MISMATCH . This function should
be called once for the client because there is currently no mechanism
to determine which raw public-key to select for the peer when there
are multiple present. Multiple raw public keys for the server can be
distinghuished by setting the names .
Note here that spki is a raw public-key as defined
in RFC7250. It means that there is no surrounding certificate that
holds the public key and that there is therefore no direct mechanism
to prove the authenticity of this key. The keypair can be used during
a TLS handshake but its authenticity should be established via a
different mechanism (e.g. TOFU or known fingerprint).
The supported formats are basic unencrypted key, PKCS8, PKCS12, and the openssl format and will be autodetected.
If the raw public-key and the private key are given in PEM encoding then the strings that hold their values must be null terminated.
Key usage (as defined by X.509 extension (2.5.29.15)) can be explicitly
set because there is no certificate structure around the key to define
this value. See for more info gnutls_x509_crt_get_key_usage() .
Note that, this function by default returns zero on success and a
negative value on error. Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2
is set using gnutls_certificate_set_flags() it returns an index
(greater or equal to zero). That index can be used in other functions
to refer to the added key-pair.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, in case the
key pair does not match GNUTLS_E_CERTIFICATE_KEY_MISMATCH is returned,
in other erroneous cases a different negative error code is returned.
Since: 3.6.6
cred: is a gnutls_certificate_credentials_t type.
spki: contains a raw public key in PKIX.SubjectPublicKeyInfo format.
pkey: contains a raw private key.
format: encoding of the keys. DER or PEM.
pass: an optional password to unlock the private key pkey.
key_usage: An ORed sequence of GNUTLS_KEY_ * flags.
names: is an array of DNS names belonging to the public-key (NULL if none).
names_length: holds the length of the names list.
flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t .
These apply to the private key pkey.
This function sets a public/private keypair in the
gnutls_certificate_credentials_t type to be used for authentication
and/or encryption. spki and privkey should match otherwise set
signatures cannot be validated. In case of no match this function
returns GNUTLS_E_CERTIFICATE_KEY_MISMATCH . This function should
be called once for the client because there is currently no mechanism
to determine which raw public-key to select for the peer when there
are multiple present. Multiple raw public keys for the server can be
distinghuished by setting the names .
Note here that spki is a raw public-key as defined
in RFC7250. It means that there is no surrounding certificate that
holds the public key and that there is therefore no direct mechanism
to prove the authenticity of this key. The keypair can be used during
a TLS handshake but its authenticity should be established via a
different mechanism (e.g. TOFU or known fingerprint).
The supported formats are basic unencrypted key, PKCS8, PKCS12, and the openssl format and will be autodetected.
If the raw public-key and the private key are given in PEM encoding then the strings that hold their values must be null terminated.
Key usage (as defined by X.509 extension (2.5.29.15)) can be explicitly
set because there is no certificate structure around the key to define
this value. See for more info gnutls_x509_crt_get_key_usage() .
Note that, this function by default returns zero on success and a
negative value on error. Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2
is set using gnutls_certificate_set_flags() it returns an index
(greater or equal to zero). That index can be used in other functions
to refer to the added key-pair.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, in case the
key pair does not match GNUTLS_E_CERTIFICATE_KEY_MISMATCH is returned,
in other erroneous cases a different negative error code is returned.
Since: 3.6.6
cred: is a gnutls_certificate_credentials_t type.
func: is the callback function
This function sets a callback to be called in order to retrieve the
certificate to be used in the handshake. The callback will take control
only if a certificate is requested by the peer. You are advised
to use gnutls_certificate_set_retrieve_function2() because it
is much more efficient in the processing it requires from gnutls.
The callback’s function prototype is: int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs, const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_retr2_st* st);
req_ca_dn is only used in X.509 certificates.
Contains a list with the CA names that the server considers trusted.
This is a hint and typically the client should send a certificate that is signed
by one of these CAs. These names, when available, are DER encoded. To get a more
meaningful value use the function gnutls_x509_rdn_get() .
pk_algos contains a list with server’s acceptable public key algorithms.
The certificate returned should support the server’s given algorithms.
st should contain the certificates and private keys.
If the callback function is provided then gnutls will call it, in the handshake, after the certificate request message has been received.
In server side pk_algos and req_ca_dn are NULL.
The callback function should set the certificate list to be sent, and return 0 on success. If no certificate was selected then the number of certificates should be set to zero. The value (-1) indicates error and the handshake will be terminated. If both certificates are set in the credentials and a callback is available, the callback takes predence.
Since: 3.0
res: is a gnutls_certificate_credentials_t type
flags: are the flags
This function will set the flags to be used for verification
of certificates and override any defaults. The provided flags must be an OR of the
gnutls_certificate_verify_flags enumerations.
cred: is a gnutls_certificate_credentials_t type.
func: is the callback function
This function sets a callback to be called when peer’s certificate has been received in order to verify it on receipt rather than doing after the handshake is completed.
The callback’s function prototype is: int (*callback)(gnutls_session_t);
If the callback function is provided then gnutls will call it, in the
handshake, just after the certificate message has been received.
To verify or obtain the certificate the gnutls_certificate_verify_peers2() ,
gnutls_certificate_type_get() , gnutls_certificate_get_peers() functions
can be used.
The callback function should return 0 for the handshake to continue or non-zero to terminate.
Since: 2.10.0
res: is a gnutls_certificate_credentials type
max_bits: is the number of bits of an acceptable certificate (default 8200)
max_depth: is maximum depth of the verification of a certificate chain (default 5)
This function will set some upper limits for the default
verification function, gnutls_certificate_verify_peers2() , to avoid
denial of service attacks. You can set them to zero to disable
limits.
res: is a gnutls_certificate_credentials_t type.
crl_list: is a list of trusted CRLs. They should have been verified before.
crl_list_size: holds the size of the crl_list
This function adds the trusted CRLs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2() . This function may be called
multiple times.
Returns: number of CRLs processed, or a negative error code on error.
Since: 2.4.0
res: is a gnutls_certificate_credentials_t type.
crlfile: is a file containing the list of verified CRLs (DER or PEM list)
type: is PEM or DER
This function adds the trusted CRLs in order to verify client or server
certificates. In case of a client this is not required
to be called if the certificates are not verified using
gnutls_certificate_verify_peers2() .
This function may be called multiple times.
Returns: number of CRLs processed or a negative error code on error.
res: is a gnutls_certificate_credentials_t type.
CRL: is a list of trusted CRLs. They should have been verified before.
type: is DER or PEM
This function adds the trusted CRLs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2() . This function may be called
multiple times.
Returns: number of CRLs processed, or a negative error code on error.
res: is a gnutls_certificate_credentials_t type.
cert_list: contains a certificate list (path) for the specified private key
cert_list_size: holds the size of the certificate list
key: is a gnutls_x509_privkey_t key
This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type. This function may be
called more than once, in case multiple keys/certificates exist for
the server. For clients that wants to send more than their own end
entity certificate (e.g., also an intermediate CA cert) then put
the certificate chain in cert_list .
Note that the certificates and keys provided, can be safely deinitialized after this function is called.
If that function fails to load the res type is at an undefined state, it must
not be reused to load other keys or certificates.
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
Since: 2.4.0
res: is a gnutls_certificate_credentials_t type.
certfile: is a file that containing the certificate list (path) for the specified private key, in PKCS7 format, or a list of certificates
keyfile: is a file that contains the private key
type: is PEM or DER
This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type. This function may be
called more than once, in case multiple keys/certificates exist for
the server. For clients that need to send more than its own end
entity certificate, e.g., also an intermediate CA cert, then the
certfile must contain the ordered certificate chain.
Note that the names in the certificate provided will be considered when selecting the appropriate certificate to use (in case of multiple certificate/key pairs).
This function can also accept URLs at keyfile and certfile . In that case it
will use the private key and certificate indicated by the URLs. Note
that the supported URLs are the ones indicated by gnutls_url_is_supported() .
In case the certfile is provided as a PKCS 11 URL, then the certificate, and its
present issuers in the token are imported (i.e., forming the required trust chain).
If that function fails to load the res structure is at an undefined state, it must
not be reused to load other keys or certificates.
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
Since: 3.1.11
res: is a gnutls_certificate_credentials_t type.
certfile: is a file that containing the certificate list (path) for the specified private key, in PKCS7 format, or a list of certificates
keyfile: is a file that contains the private key
type: is PEM or DER
pass: is the password of the key
flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t
This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type. This function may be
called more than once, in case multiple keys/certificates exist for
the server. For clients that need to send more than its own end
entity certificate, e.g., also an intermediate CA cert, then the
certfile must contain the ordered certificate chain.
Note that the names in the certificate provided will be considered when selecting the appropriate certificate to use (in case of multiple certificate/key pairs).
This function can also accept URLs at keyfile and certfile . In that case it
will use the private key and certificate indicated by the URLs. Note
that the supported URLs are the ones indicated by gnutls_url_is_supported() .
Before GnuTLS 3.4.0 when a URL was specified, the pass part was ignored and a
PIN callback had to be registered, this is no longer the case in current releases.
In case the certfile is provided as a PKCS 11 URL, then the certificate, and its
present issuers in the token are imported (i.e., forming the required trust chain).
If that function fails to load the res structure is at an undefined state, it must
not be reused to load other keys or certificates.
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
res: is a gnutls_certificate_credentials_t type.
cert: contains a certificate list (path) for the specified private key
key: is the private key, or NULL
type: is PEM or DER
This function sets a certificate/private key pair in the gnutls_certificate_credentials_t type. This function may be called more than once, in case multiple keys/certificates exist for the server.
Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates is supported. This means that certificates intended for signing cannot be used for ciphersuites that require encryption.
If the certificate and the private key are given in PEM encoding then the strings that hold their values must be null terminated.
The key may be NULL if you are using a sign callback, see
gnutls_sign_callback_set() .
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
res: is a gnutls_certificate_credentials_t type.
cert: contains a certificate list (path) for the specified private key
key: is the private key, or NULL
type: is PEM or DER
pass: is the key’s password
flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t
This function sets a certificate/private key pair in the gnutls_certificate_credentials_t type. This function may be called more than once, in case multiple keys/certificates exist for the server.
Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates is supported. This means that certificates intended for signing cannot be used for ciphersuites that require encryption.
If the certificate and the private key are given in PEM encoding then the strings that hold their values must be null terminated.
The key may be NULL if you are using a sign callback, see
gnutls_sign_callback_set() .
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
res: is a gnutls_certificate_credentials_t type.
pkcs12file: filename of file containing PKCS12 blob.
type: is PEM or DER of the pkcs12file .
password: optional password used to decrypt PKCS12 file, bags and keys.
This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t type. This function may be called more than once (in case multiple keys/certificates exist for the server).
PKCS12 files with a MAC, encrypted bags and PKCS 8
private keys are supported. However,
only password based security, and the same password for all
operations, are supported.
PKCS12 file may contain many keys and/or certificates, and this
function will try to auto-detect based on the key ID the certificate
and key pair to use. If the PKCS12 file contain the issuer of
the selected certificate, it will be appended to the certificate
to form a chain.
If more than one private keys are stored in the PKCS12 file,
then only one key will be read (and it is undefined which one).
It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
res: is a gnutls_certificate_credentials_t type.
p12blob: the PKCS12 blob.
type: is PEM or DER of the pkcs12file .
password: optional password used to decrypt PKCS12 file, bags and keys.
This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t type. This function may be called more than once (in case multiple keys/certificates exist for the server).
Encrypted PKCS12 bags and PKCS8 private keys are supported. However,
only password based security, and the same password for all
operations, are supported.
PKCS12 file may contain many keys and/or certificates, and this
function will try to auto-detect based on the key ID the certificate
and key pair to use. If the PKCS12 file contain the issuer of
the selected certificate, it will be appended to the certificate
to form a chain.
If more than one private keys are stored in the PKCS12 file,
then only one key will be read (and it is undefined which one).
It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.
Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag GNUTLS_CERTIFICATE_API_V2 is set using gnutls_certificate_set_flags()
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
Returns: On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
Since: 2.8.0
cred: is a gnutls_certificate_credentials_t type.
This function adds the system’s default trusted CAs in order to verify client or server certificates.
In the case the system is currently unsupported GNUTLS_E_UNIMPLEMENTED_FEATURE
is returned.
Returns: the number of certificates processed or a negative error code on error.
Since: 3.0.20
res: is a gnutls_certificate_credentials_t type.
ca_list: is a list of trusted CAs
ca_list_size: holds the size of the CA list
This function adds the trusted CAs in order to verify client
or server certificates. In case of a client this is not required
to be called if the certificates are not verified using
gnutls_certificate_verify_peers2() .
This function may be called multiple times.
In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
gnutls_certificate_send_x509_rdn_sequence() .
Returns: the number of certificates processed or a negative error code on error.
Since: 2.4.0
cred: is a gnutls_certificate_credentials_t type.
ca_dir: is a directory containing the list of trusted CAs (DER or PEM list)
type: is PEM or DER
This function adds the trusted CAs present in the directory in order to
verify client or server certificates. This function is identical
to gnutls_certificate_set_x509_trust_file() but loads all certificates
in a directory.
Returns: the number of certificates processed
Since: 3.3.6
cred: is a gnutls_certificate_credentials_t type.
cafile: is a file containing the list of trusted CAs (DER or PEM list)
type: is PEM or DER
This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2() . This function may be called
multiple times.
In case of a server the names of the CAs set here will be sent to
the client if a certificate request is sent. This can be disabled
using gnutls_certificate_send_x509_rdn_sequence() .
This function can also accept URLs. In that case it
will import all certificates that are marked as trusted. Note
that the supported URLs are the ones indicated by gnutls_url_is_supported() .
Returns: the number of certificates processed
res: is a gnutls_certificate_credentials_t type.
ca: is a list of trusted CAs or a DER certificate
type: is DER or PEM
This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to be
called if the certificates are not verified using
gnutls_certificate_verify_peers2() . This function may be called
multiple times.
In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
gnutls_certificate_send_x509_rdn_sequence() .
Returns: the number of certificates processed or a negative error code on error.
session: is a gnutls_session_t type.
This function returns the type of the certificate that is negotiated
for this side to send to the peer. The certificate type is by default
X.509, unless an alternative certificate type is enabled by
gnutls_init() and negotiated during the session.
Resumed sessions will return the certificate type that was negotiated and used in the original session.
As of version 3.6.4 it is recommended to use
gnutls_certificate_type_get2() which is more fine-grained.
Returns: the currently used gnutls_certificate_type_t certificate
type as negotiated for ’our’ side of the connection.
session: is a gnutls_session_t type.
target: is a gnutls_ctype_target_t type.
This function returns the type of the certificate that a side
is negotiated to use. The certificate type is by default X.509,
unless an alternative certificate type is enabled by gnutls_init() and
negotiated during the session.
The target parameter specifies whether to request the negotiated
certificate type for the client (GNUTLS_CTYPE_CLIENT ),
or for the server (GNUTLS_CTYPE_SERVER ). Additionally, in P2P mode
connection set up where you don’t know in advance who will be client
and who will be server you can use the flag (GNUTLS_CTYPE_OURS ) and
(GNUTLS_CTYPE_PEERS ) to retrieve the corresponding certificate types.
Resumed sessions will return the certificate type that was negotiated
and used in the original session. That is, this function can be used
to reliably determine the type of the certificate returned by
gnutls_certificate_get_peers() .
Returns: the currently used gnutls_certificate_type_t certificate
type for the client or the server.
Since: 3.6.4
name: is a certificate type name
The names are compared in a case insensitive way.
Returns: a gnutls_certificate_type_t for the specified in a
string certificate type, or GNUTLS_CRT_UNKNOWN on error.
type: is a certificate type
Convert a gnutls_certificate_type_t type to a string.
Returns: a string that contains the name of the specified
certificate type, or NULL in case of unknown types.
Get a list of certificate types.
Returns: a (0)-terminated list of gnutls_certificate_type_t
integers indicating the available certificate types.
status: The status flags to be printed
type: The certificate type
out: Newly allocated datum with (0) terminated string.
flags: should be zero
This function will pretty print the status of a verification
process – eg. the one obtained by gnutls_certificate_verify_peers3() .
The output out needs to be deallocated using gnutls_free() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.1.4
session: is a gnutls session
data: an array of typed data
elements: the number of data elements
status: is the output of the verification
This function will verify the peer’s certificate and store the
the status in the status variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in status is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using gnutls_certificate_set_verify_flags() . See the documentation
of gnutls_certificate_verify_peers2() for details in the verification process.
This function will take into account the stapled OCSP responses sent by the server, as well as the following X.509 certificate extensions: Name Constraints, Key Usage, and Basic Constraints (pathlen).
The acceptable data types are GNUTLS_DT_DNS_HOSTNAME , GNUTLS_DT_RFC822NAME and GNUTLS_DT_KEY_PURPOSE_OID .
The former two accept as data a null-terminated hostname or email address, and the latter a null-terminated
object identifier (e.g., GNUTLS_KP_TLS_WWW_SERVER ).
If a DNS hostname is provided then this function will compare
the hostname in the certificate against the given. If names do not match the
GNUTLS_CERT_UNEXPECTED_OWNER status flag will be set.
If a key purpose OID is provided and the end-certificate contains the extended key
usage PKIX extension, it will be required to be have the provided key purpose
or be marked for any purpose, otherwise verification status will have the
GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE flag set.
To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use gnutls_certificate_set_verify_limits() .
Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the status parameter must be checked to obtain the validation status.
Since: 3.3.0
session: is a gnutls session
status: is the output of the verification
This function will verify the peer’s certificate and store
the status in the status variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in status is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using gnutls_certificate_set_verify_flags() .
This function will take into account the stapled OCSP responses sent by the server, as well as the following X.509 certificate extensions: Name Constraints, Key Usage, and Basic Constraints (pathlen).
Note that you must also check the peer’s name in order to check if
the verified certificate belongs to the actual peer, see gnutls_x509_crt_check_hostname() ,
or use gnutls_certificate_verify_peers3() .
To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use gnutls_certificate_set_verify_limits() .
Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the status parameter must be checked to obtain the validation status.
session: is a gnutls session
hostname: is the expected name of the peer; may be NULL
status: is the output of the verification
This function will verify the peer’s certificate and store the
the status in the status variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in status is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using gnutls_certificate_set_verify_flags() . See the documentation
of gnutls_certificate_verify_peers2() for details in the verification process.
This function will take into account the stapled OCSP responses sent by the server, as well as the following X.509 certificate extensions: Name Constraints, Key Usage, and Basic Constraints (pathlen).
If the hostname provided is non-NULL then this function will compare
the hostname in the certificate against it. The comparison will follow
the RFC6125 recommendations. If names do not match the
GNUTLS_CERT_UNEXPECTED_OWNER status flag will be set.
In order to verify the purpose of the end-certificate (by checking the extended
key usage), use gnutls_certificate_verify_peers() .
To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use gnutls_certificate_set_verify_limits() .
Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the status parameter must be checked to obtain the validation status.
Since: 3.1.4
req_version: version string to compare with, or NULL .
Check the GnuTLS Library version against the provided string.
See GNUTLS_VERSION for a suitable req_version string.
See also gnutls_check_version_numeric() , which provides this
functionality as a macro.
Returns: Check that the version of the library is at
minimum the one given as a string in req_version and return the
actual version string of the library; return NULL if the
condition is not met. If NULL is passed to this function no
check is done and only the version string is returned.
session: is a gnutls_session_t type.
Get the currently used cipher.
Returns: the currently used cipher, a gnutls_cipher_algorithm_t
type.
name: is a cipher algorithm name
The names are compared in a case insensitive way.
Returns: return a gnutls_cipher_algorithm_t value corresponding to
the specified cipher, or GNUTLS_CIPHER_UNKNOWN on error.
algorithm: is an encryption algorithm
This function returns the key size of the provided algorithm.
Returns: length (in bytes) of the given cipher’s key size, or 0 if the given cipher is invalid.
algorithm: is an encryption algorithm
Convert a gnutls_cipher_algorithm_t type to a string.
Returns: a pointer to a string that contains the name of the
specified cipher, or NULL .
Get a list of supported cipher algorithms. Note that not
necessarily all ciphers are supported as TLS cipher suites. For
example, DES is not supported as a cipher suite, but is supported
for other purposes (e.g., PKCS8 or similar).
This function is not thread safe.
Returns: a (0)-terminated list of gnutls_cipher_algorithm_t
integers indicating the available ciphers.
kx_algorithm: is a Key exchange algorithm
cipher_algorithm: is a cipher algorithm
mac_algorithm: is a MAC algorithm
This function returns the ciphersuite name under TLS1.2 or earlier versions when provided with individual algorithms. The full cipher suite name must be prepended by TLS or SSL depending of the protocol in use.
To get a description of the current ciphersuite across versions, it
is recommended to use gnutls_session_get_desc() .
Returns: a string that contains the name of a TLS cipher suite,
specified by the given algorithms, or NULL .
idx: index of cipher suite to get information about, starts on 0.
cs_id: output buffer with room for 2 bytes, indicating cipher suite value
kx: output variable indicating key exchange algorithm, or NULL .
cipher: output variable indicating cipher, or NULL .
mac: output variable indicating MAC algorithm, or NULL .
min_version: output variable indicating TLS protocol version, or NULL .
Get information about supported cipher suites. Use the function iteratively to get information about all supported cipher suites. Call with idx=0 to get information about first cipher suite, then idx=1 and so on until the function returns NULL.
Returns: the name of idx cipher suite, and set the information
about the cipher suite in the output variables. If idx is out of
bounds, NULL is returned.
session: is a gnutls_session_t type.
Get the canonical name of negotiated TLS ciphersuite. The names returned by this function match the IANA registry, with one exception:
TLS_DHE_DSS_RC4_128_SHA { 0x00, 0x66 }
which is reserved for compatibility.
To get a detailed description of the current ciphersuite, it is
recommended to use gnutls_session_get_desc() .
Returns: a string that contains the canonical name of a TLS ciphersuite,
or NULL if the handshake is not completed.
Since: 3.7.4
session: is a gnutls_session_t type.
This function returns the certificate compression method that has been selected to compress the certificate before sending it to the peer. The selection is done based on the local list of supported compression methods and the peer’s requested compression methods.
Returns: selected certificate compression method.
Since 3.7.4
session: is a gnutls_session_t type.
methods: is a list of supported compression methods.
methods_len: number of compression methods in methods
This function sets the supported compression methods for certificate compression for the given session. The list of supported compression methods will be used for a) requesting the compression of peer’s certificate and b) selecting the method to compress the local certificate before sending it to the peer. The order of compression methods inside the list does matter as the method that appears earlier in the list will be preferred before the later ones. Note that even if you set the list of supported compression methods, the compression might not be used if the peer does not support any of your chosen compression methods.
The list of supported compression methods must meet the following criteria:
Argument methods must be an array of valid compression methods of type
gnutls_compression_method_t . Argument methods_len must contain the number of
compression methods stored in the methods array and must be within range <1, 127>.
The length constraints are defined by MIN_COMPRESS_CERTIFICATE_METHODS
and MAX_COMPRESS_CERTIFICATE_METHODS macros located in the header file
compress_certificate.h.
If either methods or methods_len is equal to 0, current list of supported
compression methods will be unset.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since 3.7.4
session: is a gnutls_session_t type.
Clears all the credentials previously set in this session.
session: is a gnutls_session_t type.
type: is the type of the credentials to return
cred: will contain the credentials.
Returns the previously provided credentials structures.
For GNUTLS_CRD_ANON , cred will be
gnutls_anon_client_credentials_t in case of a client. In case of
a server it should be gnutls_anon_server_credentials_t .
For GNUTLS_CRD_SRP , cred will be gnutls_srp_client_credentials_t
in case of a client, and gnutls_srp_server_credentials_t , in case
of a server.
For GNUTLS_CRD_CERTIFICATE , cred will be
gnutls_certificate_credentials_t .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.3.3
session: is a gnutls_session_t type.
type: is the type of the credentials
cred: the credentials to set
Sets the needed credentials for the specified type. E.g. username,
password - or public and private keys etc. The cred parameter is
a structure that depends on the specified type and on the current
session (client or server).
In order to minimize memory usage, and share credentials between
several threads gnutls keeps a pointer to cred, and not the whole
cred structure. Thus you will have to keep the structure allocated
until you call gnutls_deinit() .
For GNUTLS_CRD_ANON , cred should be
gnutls_anon_client_credentials_t in case of a client. In case of
a server it should be gnutls_anon_server_credentials_t .
For GNUTLS_CRD_SRP , cred should be gnutls_srp_client_credentials_t
in case of a client, and gnutls_srp_server_credentials_t , in case
of a server.
For GNUTLS_CRD_CERTIFICATE , cred should be
gnutls_certificate_credentials_t .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
session: is a gnutls_session_t type.
session_entry: is the session data (not key)
This function has no effect.
Returns: Returns GNUTLS_E_EXPIRED , if the database entry has
expired or 0 otherwise.
Deprecated: This function is deprecated.
entry: is a pointer to a gnutls_datum_t type.
This function returns the time that this entry will expire. It can be used for database entry expiration.
Returns: The time this entry will expire, or zero on error.
Since: 3.6.5
entry: is a pointer to a gnutls_datum_t type.
This function returns the time that this entry was active. It can be used for database entry expiration.
Returns: The time this entry was created, or zero on error.
Returns the expiration time (in seconds) of stored sessions for resumption.
session: is a gnutls_session_t type.
Get db function pointer.
Returns: the pointer that will be sent to db store, retrieve and delete functions, as the first argument.
session: is a gnutls_session_t type.
This function will remove the current session data from the
session database. This will prevent future handshakes reusing
these session data. This function should be called if a session
was terminated abnormally, and before gnutls_deinit() is called.
Normally gnutls_deinit() will remove abnormally terminated
sessions.
session: is a gnutls_session_t type.
seconds: is the number of seconds.
Set the expiration time for resumed sessions. The default is 21600 (6 hours) at the time of writing.
The maximum value that can be set using this function is 604800 (7 days).
session: is a gnutls_session_t type.
ptr: is the pointer
Sets the pointer that will be provided to db store, retrieve and delete functions, as the first argument.
session: is a gnutls_session_t type.
rem_func: is the function.
Sets the function that will be used to remove data from the resumed sessions database. This function must return 0 on success.
The first argument to rem_func will be null unless
gnutls_db_set_ptr() has been called.
session: is a gnutls_session_t type.
retr_func: is the function.
Sets the function that will be used to retrieve data from the resumed sessions database. This function must return a gnutls_datum_t containing the data on success, or a gnutls_datum_t containing null and 0 on failure.
The datum’s data must be allocated using the function
gnutls_malloc() .
The first argument to retr_func will be null unless
gnutls_db_set_ptr() has been called.
session: is a gnutls_session_t type.
store_func: is the function
Sets the function that will be used to store data in the resumed sessions database. This function must return 0 on success.
The first argument to store_func will be null unless
gnutls_db_set_ptr() has been called.
session: is a gnutls_session_t type.
This function clears all buffers associated with the session .
This function will also remove session data from the session
database if the session was terminated abnormally.
session: is a gnutls session
raw_gen: will hold the generator.
raw_prime: will hold the prime.
This function will return the group parameters used in the last
Diffie-Hellman key exchange with the peer. These are the prime and
the generator used. This function should be used for both
anonymous and ephemeral Diffie-Hellman. The output parameters must
be freed with gnutls_free() .
Note, that the prime and generator are exported as non-negative integers and may include a leading zero byte.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls session
Get the Diffie-Hellman public key bit size. Can be used for both anonymous and ephemeral Diffie-Hellman.
Returns: The public key bit size used in the last Diffie-Hellman key exchange with the peer, or a negative error code in case of error.
session: is a gnutls session
This function will return the bits of the prime used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman. Note that some ciphers, like RSA and DSA without DHE, do not use a Diffie-Hellman key exchange, and then this function will return 0.
Returns: The Diffie-Hellman bit strength is returned, or 0 if no Diffie-Hellman key exchange was done, or a negative error code on failure.
session: is a gnutls session
raw_key: will hold the public key.
This function will return the peer’s public key used in the last
Diffie-Hellman key exchange. This function should be used for both
anonymous and ephemeral Diffie-Hellman. The output parameters must
be freed with gnutls_free() .
Note, that public key is exported as non-negative integer and may include a leading zero byte.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls session
This function will return the bits used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
dst: Is the destination parameters, which should be initialized.
src: Is the source parameters
This function will copy the DH parameters structure from source to destination. The destination should be already initialized.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
This function will deinitialize the DH parameters type.
params: Holds the DH parameters
format: the format of output params. One of PEM or DER.
out: will contain a PKCS3 DHParams structure PEM or DER encoded
This function will export the given dh parameters to a PKCS3
DHParams structure. This is the format generated by "openssl dhparam" tool.
The data in out will be allocated using gnutls_malloc() .
If the structure is PEM encoded, it will have a header of "BEGIN DH PARAMETERS".
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.1.3
params: Holds the DH parameters
format: the format of output params. One of PEM or DER.
params_data: will contain a PKCS3 DHParams structure PEM or DER encoded
params_data_size: holds the size of params_data (and will be replaced by the actual size of parameters)
This function will export the given dh parameters to a PKCS3 DHParams structure. This is the format generated by "openssl dhparam" tool. If the buffer provided is not long enough to hold the output, then GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
If the structure is PEM encoded, it will have a header of "BEGIN DH PARAMETERS".
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
params: Holds the DH parameters
prime: will hold the new prime
generator: will hold the new generator
bits: if non null will hold the secret key’s number of bits
This function will export the pair of prime and generator for use
in the Diffie-Hellman key exchange. The new parameters will be
allocated using gnutls_malloc() and will be stored in the
appropriate datum.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dparams: The parameters
bits: is the prime’s number of bits
This function will generate a new pair of prime and generator for use in the Diffie-Hellman key exchange. This may take long time.
It is recommended not to set the number of bits directly, but
use gnutls_sec_param_to_pk_bits() instead.
Also note that the DH parameters are only useful to servers.
Since clients use the parameters sent by the server, it’s of
no use to call this in client side.
The parameters generated are of the DSA form. It also is possible
to generate provable parameters (following the Shawe-Taylor
algorithm), using gnutls_x509_privkey_generate2() with DSA option
and the GNUTLS_PRIVKEY_FLAG_PROVABLE flag set. These can the
be imported with gnutls_dh_params_import_dsa() .
It is no longer recommended for applications to generate parameters. See the "Parameter generation" section in the manual.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
key: holds a DSA private key
This function will import the prime and generator of the DSA key for use in the Diffie-Hellman key exchange.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
params: The parameters
pkcs3_params: should contain a PKCS3 DHParams structure PEM or DER encoded
format: the format of params. PEM or DER.
This function will extract the DHParams found in a PKCS3 formatted structure. This is the format generated by "openssl dhparam" tool.
If the structure is PEM encoded, it should have a header of "BEGIN DH PARAMETERS".
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
prime: holds the new prime
generator: holds the new generator
This function will replace the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters should be stored in the appropriate gnutls_datum.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
prime: holds the new prime
generator: holds the new generator
key_bits: the private key bits (set to zero when unknown)
This function will replace the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters should be stored in the appropriate gnutls_datum.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
prime: holds the new prime
q: holds the subgroup if available, otherwise NULL
generator: holds the new generator
This function will replace the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters should be stored in the appropriate gnutls_datum.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
dh_params: The parameters
This function will initialize the DH parameters type.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
session: is a gnutls_session_t type.
bits: is the number of bits
This function sets the number of bits, for use in a Diffie-Hellman key exchange. This is used both in DH ephemeral and DH anonymous cipher suites. This will set the minimum size of the prime that will be used for the handshake.
In the client side it sets the minimum accepted number of bits. If
a server sends a prime with less bits than that
GNUTLS_E_DH_PRIME_UNACCEPTABLE will be returned by the handshake.
Note that this function will warn via the audit log for value that are believed to be weak.
The function has no effect in server side.
Note that since 3.1.7 this function is deprecated. The minimum
number of bits is set by the priority string level.
Also this function must be called after gnutls_priority_set_direct()
or the set value may be overridden by the selected priority options.
name: is a digest algorithm name
Convert a string to a gnutls_digest_algorithm_t value. The names are
compared in a case insensitive way.
Returns: a gnutls_digest_algorithm_t id of the specified MAC
algorithm string, or GNUTLS_DIG_UNKNOWN on failure.
algorithm: is a digest algorithm
Convert a gnutls_digest_algorithm_t value to a string.
Returns: a string that contains the name of the specified digest
algorithm, or NULL .
algorithm: is a digest algorithm
Convert a gnutls_digest_algorithm_t value to its object identifier.
Returns: a string that contains the object identifier of the specified digest
algorithm, or NULL .
Since: 3.4.3
Get a list of hash (digest) algorithms supported by GnuTLS.
This function is not thread safe.
Returns: Return a (0)-terminated list of gnutls_digest_algorithm_t
integers indicating the available digests.
dig: is a digest algorithm
secure: whether to mark the digest algorithm secure
Modify the previous system wide setting that marked dig as secure
or insecure. This only has effect when the algorithm is enabled
through the allowlisting mode in the configuration file, or when
the setting is modified with a prior call to this function.
Since: 3.7.3
session: is a gnutls_session_t type.
Get the cipher algorithm used for encrypting early data.
Returns: the cipher used for early data, a
gnutls_cipher_algorithm_t type.
Since: 3.7.2
session: is a gnutls_session_t type.
Get the hash algorithm used as a PRF to derive keys for encrypting early data in TLS 1.3.
Returns: the hash algorithm used for early data, a
gnutls_digest_algorithm_t value.
Since: 3.7.2
session: is a gnutls_session_t type.
Returns the currently used elliptic curve for key exchange. Only valid when using an elliptic curve ciphersuite.
Returns: the currently used curve, a gnutls_ecc_curve_t
type.
Since: 3.0
name: is a curve name
The names are compared in a case insensitive way.
Returns: return a gnutls_ecc_curve_t value corresponding to
the specified curve, or GNUTLS_ECC_CURVE_INVALID on error.
Since: 3.4.3
curve: is an ECC curve
Convert a gnutls_ecc_curve_t value to a string.
Returns: a string that contains the name of the specified
curve or NULL .
Since: 3.0
curve: is an ECC curve
Convert a gnutls_ecc_curve_t value to its object identifier.
Returns: a string that contains the OID of the specified
curve or NULL .
Since: 3.4.3
curve: is an ECC curve
Returns: the public key algorithm associated with the named curve or GNUTLS_PK_UNKNOWN .
Since: 3.5.0
curve: is an ECC curve
Returns: the size in bytes of the curve or 0 on failure.
Since: 3.0
Get the list of supported elliptic curves.
This function is not thread safe.
Returns: Return a (0)-terminated list of gnutls_ecc_curve_t
integers indicating the available curves.
curve: is an ECC curve
enabled: whether to enable the curve
Modify the previous system wide setting that marked curve as
enabled or disabled. Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
This function is not thread-safe and is intended to be called in the main thread at the beginning of the process execution.
Returns: 0 on success or negative error code otherwise.
Since: 3.7.3
error: is a GnuTLS error code, a negative error code
If a GnuTLS function returns a negative error code you may feed that value to this function to see if the error condition is fatal to a TLS session (i.e., must be terminated).
Note that you may also want to check the error code manually, since some non-fatal errors to the protocol (such as a warning alert or a rehandshake request) may be fatal for your program.
This function is only useful if you are dealing with errors from functions that relate to a TLS session (e.g., record layer or handshake layer handling functions).
Returns: Non-zero value on fatal errors or zero on non-fatal.
err: is a negative integer
level: the alert level will be stored there
Get an alert depending on the error code returned by a gnutls
function. All alerts sent by this function should be considered
fatal. The only exception is when err is GNUTLS_E_REHANDSHAKE ,
where a warning alert should be sent to the peer indicating that no
renegotiation will be performed.
If there is no mapping to a valid alert the alert to indicate
internal error (GNUTLS_A_INTERNAL_ERROR ) is returned.
Returns: the alert code to use for a particular error code.
version: is a gnutls_protocol_t value
cipher: is a gnutls_cipher_algorithm_t value
mac: is a gnutls_mac_algorithm_t value
comp: is a gnutls_compression_method_t value (ignored)
flags: must be zero
This function will return the set size in bytes of the overhead due to TLS (or DTLS) per record.
Note that this function may provide inaccurate values when TLS
extensions that modify the record format are negotiated. In these
cases a more accurate value can be obtained using gnutls_record_overhead_size()
after a completed handshake.
Since: 3.2.2
session: a gnutls_session_t opaque pointer
This function allows an extension handler to obtain the message
this extension is being called from. The returned value is a single
entry of the gnutls_ext_flags_t enumeration. That is, if an
extension was registered with the GNUTLS_EXT_FLAG_HRR and
GNUTLS_EXT_FLAG_EE flags, the value when called during parsing of the
encrypted extensions message will be GNUTLS_EXT_FLAG_EE .
If not called under an extension handler, its value is undefined.
Since: 3.6.3
session: a gnutls_session_t opaque pointer
tls_id: the numeric id of the extension
data: a pointer to the private data to retrieve
This function retrieves any data previously stored with gnutls_ext_set_data() .
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
ext: is a TLS extension numeric ID
Convert a TLS extension numeric ID to a printable string.
Returns: a pointer to a string that contains the name of the
specified cipher, or NULL .
session: a gnutls_session_t opaque pointer
tls_id: is a TLS extension numeric ID
parse_point: the parse type of the extension
Convert a TLS extension numeric ID to a printable string.
Returns: a pointer to a string that contains the name of the
specified cipher, or NULL .
ctx: a pointer to pass to callback function
cb: callback function to process each extension found
data: TLS extension data
flags: should be zero or GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO or GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO
This function iterates through the TLS extensions as passed in
data , passing the individual extension data to callback. The
data must conform to Extension extensions<0..2^16-1> format.
If flags is GNUTLS_EXT_RAW_TLS_FLAG_CLIENT_HELLO then this function
will parse the extension data from the position, as if the packet in
data is a client hello (without record or handshake headers) -
as provided by gnutls_handshake_set_hook_function() .
The return value of the callback will be propagated.
Returns: GNUTLS_E_SUCCESS on success, or an error code. On unknown
flags it returns GNUTLS_E_INVALID_REQUEST .
Since: 3.6.3
name: the name of the extension to register
id: the numeric TLS id of the extension
parse_point: the parse type of the extension (see gnutls_ext_parse_type_t)
recv_func: a function to receive the data
send_func: a function to send the data
deinit_func: a function deinitialize any private data
pack_func: a function which serializes the extension’s private data (used on session packing for resumption)
unpack_func: a function which will deserialize the extension’s private data
This function will register a new extension type. The extension will remain
registered until gnutls_global_deinit() is called. If the extension type
is already registered then GNUTLS_E_ALREADY_REGISTERED will be returned.
Each registered extension can store temporary data into the gnutls_session_t
structure using gnutls_ext_set_data() , and they can be retrieved using
gnutls_ext_get_data() .
Any extensions registered with this function are valid for the client and TLS1.2 server hello (or encrypted extensions for TLS1.3).
This function is not thread safe.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
session: a gnutls_session_t opaque pointer
tls_id: the numeric id of the extension
data: the private data to set
This function allows an extension handler to store data in the current session and retrieve them later on. The set data will be deallocated using the gnutls_ext_deinit_data_func.
Since: 3.4.0
algo: is a digest algorithm
data: is the data
result: is the place where the result will be copied (may be null).
result_size: should hold the size of the result. The actual size of the returned result will also be copied there.
This function will calculate a fingerprint (actually a hash), of the given data. The result is not printable data. You should convert it to hex, or to something else printable.
This is the usual way to calculate a fingerprint of an X.509 DER encoded certificate. Note however that the fingerprint of an OpenPGP certificate is not just a hash and cannot be calculated with this function.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
context: a gnutls_fips140_context_t
Uninitialize and release the FIPS context context .
Since: 3.7.3
context: location to store gnutls_fips140_context_t
Create and initialize the FIPS context object.
Returns: 0 upon success, a negative error code otherwise
Since: 3.7.3
context: a gnutls_fips140_context_t
Get the previous operation state of context in terms of FIPS.
Returns: a gnutls_fips140_operation_state_t
Since: 3.7.3
Checks whether this library is in FIPS140 mode. The returned
value corresponds to the library mode as set with
gnutls_fips140_set_mode() .
If gnutls_fips140_set_mode() was called with GNUTLS_FIPS140_SET_MODE_THREAD
then this function will return the current thread’s FIPS140 mode, otherwise
the global value is returned.
Returns: return non-zero if true or zero if false.
Since: 3.3.0
Dissociate the FIPS context currently
active on the current thread, reverting to the previously active
context. If a cryptographic operation is ongoing in the current
thread, e.g., gnutls_aead_cipher_init() is called but
gnutls_aead_cipher_deinit() is not yet called, it returns an error
GNUTLS_E_INVALID_REQUEST .
This function is no-op if FIPS140 is not compiled in nor enabled at run-time.
Returns: 0 upon success, a negative error code otherwise
Since: 3.7.3
context: a gnutls_fips140_context_t
Associate the FIPS context to the current thread, diverting the
currently active context. If a cryptographic operation is ongoing
in the current thread, e.g., gnutls_aead_cipher_init() is called
but gnutls_aead_cipher_deinit() is not yet called, it returns an
error GNUTLS_E_INVALID_REQUEST .
The operation state of context will be reset to
GNUTLS_FIPS140_OP_INITIAL .
This function is no-op if FIPS140 is not compiled in nor enabled at run-time.
Returns: 0 upon success, a negative error code otherwise
Since: 3.7.3
Manually perform the second round of the FIPS140 self-tests, including:
- Known answer tests (KAT) for the selected set of symmetric cipher, MAC, public key, KDF, and DRBG - Library integrity checks
Upon failure with FIPS140 mode enabled, it makes the library unusable. This function is not thread-safe.
Returns: 0 upon success, a negative error code otherwise
Since: 3.7.7
mode: the FIPS140-2 mode to switch to
flags: should be zero or GNUTLS_FIPS140_SET_MODE_THREAD
That function is not thread-safe when changing the mode with no flags (globally), and should be called prior to creating any threads. Its behavior with no flags after threads are created is undefined.
When the flag GNUTLS_FIPS140_SET_MODE_THREAD is specified
then this call will change the FIPS140-2 mode for this particular
thread and not for the whole process. That way an application
can utilize this function to set and reset mode for specific
operations.
This function never fails but will be a no-op if used when
the library is not in FIPS140-2 mode. When asked to switch to unknown
values for mode or to GNUTLS_FIPS140_SELFTESTS mode, the library
switches to GNUTLS_FIPS140_STRICT mode.
Since: 3.6.2
Returns the library configuration as key value pairs. Currently defined keys are:
- fips-module-name: the name of the FIPS140 module
- fips-module-version: the version of the FIPS140 module
- libgnutls-soname: the SONAME of the library itself
- libnettle-soname: the library SONAME of linked libnettle
- libhogweed-soname: the library SONAME of linked libhogweed
- libgmp-soname: the library SONAME of linked libgmp
- hardware-features: enabled hardware support features
- tls-features: enabled TLS protocol features
Returns: a NUL-terminated gnutls_library_config_st array
Since: 3.7.3
Returns the filename of the system wide configuration file to be loaded by the library.
Returns: a constant pointer to the config file path
Since: 3.6.9
This function deinitializes the global data, that were initialized
using gnutls_global_init() .
Since GnuTLS 3.3.0 this function is no longer necessary to be explicitly
called. GnuTLS will automatically deinitialize on library destructor. See
gnutls_global_init() for disabling the implicit initialization/deinitialization.
Since GnuTLS 3.3.0 this function is no longer necessary to be explicitly
called. To disable the implicit call (in a library constructor) of this
function set the environment variable GNUTLS_NO_IMPLICIT_INIT to 1.
This function performs any required precalculations, detects
the supported CPU capabilities and initializes the underlying
cryptographic backend. In order to free any resources
taken by this call you should gnutls_global_deinit()
when gnutls usage is no longer needed.
This function increments a global counter, so that
gnutls_global_deinit() only releases resources when it has been
called as many times as gnutls_global_init() . This is useful when
GnuTLS is used by more than one library in an application. This
function can be called many times, but will only do something the
first time. It is thread safe since GnuTLS 3.3.0.
A subsequent call of this function if the initial has failed will return the same error code.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
log_func: it is the audit log function
This is the function to set the audit logging function. This
is a function to report important issues, such as possible
attacks in the protocol. This is different from gnutls_global_set_log_function()
because it will report also session-specific events. The session
parameter will be null if there is no corresponding TLS session.
gnutls_audit_log_func is of the form,
void (*gnutls_audit_log_func)( gnutls_session_t, const char*);
Since: 3.0
log_func: it’s a log function
This is the function where you set the logging function gnutls is going to use. This function only accepts a character array. Normally you may not use this function since it is only used for debugging purposes.
gnutls_log_func is of the form,
void (*gnutls_log_func)( int level, const char*);
level: it’s an integer from 0 to 99.
This is the function that allows you to set the log level. The level is an integer between 0 and 9. Higher values mean more verbosity. The default value is 0. Larger values should only be used with care, since they may reveal sensitive information.
Use a log level over 10 to enable all debugging options.
init: mutex initialization function
deinit: mutex deinitialization function
lock: mutex locking function
unlock: mutex unlocking function
With this function you are allowed to override the default mutex locks used in some parts of gnutls and dependent libraries. This function should be used if you have complete control of your program and libraries. Do not call this function from a library, or preferably from any application unless really needed to. GnuTLS will use the appropriate locks for the running system.
This function must be called prior to any other GnuTLS function; otherwise the behavior is undefined.
Deprecated: This function is discouraged on GnuTLS 3.7.3 or later.
Since: 2.12.0
time_func: it’s the system time function, a gnutls_time_func() callback.
This is the function where you can override the default system time function. The application provided function should behave the same as the standard function.
Since: 2.12.0
param: is a GOST 28147 param set
Convert a gnutls_gost_paramset_t value to a string.
Returns: a string that contains the name of the specified GOST param set,
or NULL .
Since: 3.6.3
param: is a GOST 28147 param set
Convert a gnutls_gost_paramset_t value to its object identifier.
Returns: a string that contains the object identifier of the specified GOST
param set, or NULL .
Since: 3.6.3
session: is a gnutls_session_t type.
Returns the currently used group for key exchange. Only valid when using an elliptic curve or DH ciphersuite.
Returns: the currently used group, a gnutls_group_t
type.
Since: 3.6.0
name: is a group name
The names are compared in a case insensitive way.
Returns: return a gnutls_group_t value corresponding to
the specified group, or GNUTLS_GROUP_INVALID on error.
Since: 3.6.0
group: is an element from gnutls_group_t
Convert a gnutls_group_t value to a string.
Returns: a string that contains the name of the specified
group or NULL .
Since: 3.6.0
Get the list of supported elliptic curves.
This function is not thread safe.
Returns: Return a (0)-terminated list of gnutls_group_t
integers indicating the available groups.
Since: 3.6.0
session: is a gnutls_session_t type.
This function performs the handshake of the TLS/SSL protocol, and initializes the TLS session parameters.
The non-fatal errors expected by this function are:
GNUTLS_E_INTERRUPTED , GNUTLS_E_AGAIN ,
GNUTLS_E_WARNING_ALERT_RECEIVED . When this function is called
for re-handshake under TLS 1.2 or earlier, the non-fatal error code
GNUTLS_E_GOT_APPLICATION_DATA may also be returned.
The former two interrupt the handshake procedure due to the transport
layer being interrupted, and the latter because of a "warning" alert that
was sent by the peer (it is always a good idea to check any
received alerts). On these non-fatal errors call this function again,
until it returns 0; cf. gnutls_record_get_direction() and
gnutls_error_is_fatal() . In DTLS sessions the non-fatal error
GNUTLS_E_LARGE_PACKET is also possible, and indicates that
the MTU should be adjusted.
When this function is called by a server after a rehandshake request
under TLS 1.2 or earlier the GNUTLS_E_GOT_APPLICATION_DATA error code indicates
that some data were pending prior to peer initiating the handshake.
Under TLS 1.3 this function when called after a successful handshake, is a no-op
and always succeeds in server side; in client side this function is
equivalent to gnutls_session_key_update() with GNUTLS_KU_PEER flag.
This function handles both full and abbreviated TLS handshakes (resumption).
For abbreviated handshakes, in client side, the gnutls_session_set_data()
should be called prior to this function to set parameters from a previous session.
In server side, resumption is handled by either setting a DB back-end, or setting
up keys for session tickets.
Returns: GNUTLS_E_SUCCESS on a successful handshake, otherwise a negative error code.
type: is a handshake message description
Convert a gnutls_handshake_description_t value to a string.
Returns: a string that contains the name of the specified handshake
message or NULL .
session: is a gnutls_session_t type.
This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.
Check gnutls_handshake_description_t in gnutls.h for the
available handshake descriptions.
Returns: the last handshake message type received, a
gnutls_handshake_description_t .
session: is a gnutls_session_t type.
This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.
Check gnutls_handshake_description_t in gnutls.h for the
available handshake descriptions.
Returns: the last handshake message type sent, a
gnutls_handshake_description_t .
session: is a gnutls_session_t type
htype: the gnutls_handshake_description_t of the message to hook at
when: GNUTLS_HOOK_ * depending on when the hook function should be called
func: is the function to be called
This function will set a callback to be called after or before the specified
handshake message has been received or generated. This is a
generalization of gnutls_handshake_set_post_client_hello_function() .
To call the hook function prior to the message being generated or processed
use GNUTLS_HOOK_PRE as when parameter, GNUTLS_HOOK_POST to call
after, and GNUTLS_HOOK_BOTH for both cases.
This callback must return 0 on success or a gnutls error code to terminate the handshake.
To hook at all handshake messages use an htype of GNUTLS_HANDSHAKE_ANY .
Warning: You should not use this function to terminate the handshake based on client input unless you know what you are doing. Before the handshake is finished there is no way to know if there is a man-in-the-middle attack being performed.
session: is a gnutls_session_t type.
max: is the maximum number.
This function will set the maximum size of all handshake messages.
Handshakes over this size are rejected with
GNUTLS_E_HANDSHAKE_TOO_LARGE error code. The default value is
128kb which is typically large enough. Set this to 0 if you do not
want to set an upper limit.
The reason for restricting the handshake message sizes are to limit Denial of Service attacks.
Note that the maximum handshake size was increased to 128kb from 48kb in GnuTLS 3.5.5.
session: is a gnutls_session_t type.
func: is the function to be called
This function will set a callback to be called after the client hello has been received (callback valid in server side only). This allows the server to adjust settings based on received extensions.
Those settings could be ciphersuites, requesting certificate, or anything else except for version negotiation (this is done before the hello message is parsed).
This callback must return 0 on success or a gnutls error code to terminate the handshake.
Since GnuTLS 3.3.5 the callback is
allowed to return GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED to
put the handshake on hold. In that case gnutls_handshake()
will return GNUTLS_E_INTERRUPTED and can be resumed when needed.
Warning: You should not use this function to terminate the handshake based on client input unless you know what you are doing. Before the handshake is finished there is no way to know if there is a man-in-the-middle attack being performed.
session: is a gnutls_session_t type.
allow: is an integer (0 or 1)
This function will enable or disable the use of private cipher
suites (the ones that start with 0xFF). By default or if allow is 0 then these cipher suites will not be advertised nor used.
Currently GnuTLS does not include such cipher-suites or compression algorithms.
Enabling the private ciphersuites when talking to other than gnutls servers and clients may cause interoperability problems.
session: is a gnutls_session_t type.
random: a random value of 32-bytes
This function will explicitly set the server or client hello random value in the subsequent TLS handshake. The random value should be a 32-byte value.
Note that this function should not normally be used as gnutls will select automatically a random value for the handshake.
This function should not be used when resuming a session.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since 3.1.9
session: is gnutls_session_t type
func: is the function to be called
This function will set a callback to be called when a handshake message is being sent.
Since: 3.7.0
session: is a gnutls_session_t type.
func: the secret func
This function will set a callback to be called when a new traffic secret is installed.
Since: 3.7.0
session: is a gnutls_session_t type.
ms: is a timeout value in milliseconds
This function sets the timeout for the TLS handshake process
to the provided value. Use an ms value of zero to disable
timeout, or GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT for a reasonable
default value. For the DTLS protocol, the more detailed
gnutls_dtls_set_timeouts() is provided.
This function requires to set a pull timeout callback. See
gnutls_transport_set_pull_timeout_function() .
Since: 3.1.0
session: is a gnutls_session_t type.
level: the current encryption level for reading a handshake message
data: the (const) handshake data to be processed
data_size: the size of data
This function processes a handshake message in the encryption level
specified with level . Prior to calling this function, a handshake
read callback must be set on session . Use
gnutls_handshake_set_read_function() to do this.
Since: 3.7.0
session: is a gnutls_session_t type.
type: one of GNUTLS_HB_LOCAL_ALLOWED_TO_SEND and GNUTLS_HB_PEER_ALLOWED_TO_SEND
This function will check whether heartbeats are allowed to be sent or received in this session.
Returns: Non zero if heartbeats are allowed.
Since: 3.1.2
session: is a gnutls_session_t type.
type: one of the GNUTLS_HB_* flags
If this function is called with the GNUTLS_HB_PEER_ALLOWED_TO_SEND
type , GnuTLS will allow heartbeat messages to be received. Moreover it also
request the peer to accept heartbeat messages. This function
must be called prior to TLS handshake.
If the type used is GNUTLS_HB_LOCAL_ALLOWED_TO_SEND , then the peer
will be asked to accept heartbeat messages but not send ones.
The function gnutls_heartbeat_allowed() can be used to test Whether
locally generated heartbeat messages can be accepted by the peer.
Since: 3.1.2
session: is a gnutls_session_t type.
This function will return the milliseconds remaining
for a retransmission of the previously sent ping
message. This function is useful when ping is used in
non-blocking mode, to estimate when to call gnutls_heartbeat_ping()
if no packets have been received.
Returns: the remaining time in milliseconds.
Since: 3.1.2
session: is a gnutls_session_t type.
data_size: is the length of the ping payload.
max_tries: if flags is GNUTLS_HEARTBEAT_WAIT then this sets the number of retransmissions. Use zero for indefinite (until timeout).
flags: if GNUTLS_HEARTBEAT_WAIT then wait for pong or timeout instead of returning immediately.
This function sends a ping to the peer. If the flags is set
to GNUTLS_HEARTBEAT_WAIT then it waits for a reply from the peer.
Note that it is highly recommended to use this function with the
flag GNUTLS_HEARTBEAT_WAIT , or you need to handle retransmissions
and timeouts manually.
The total TLS data transmitted as part of the ping message are given by
the following formula: MAX(16, data_size )+gnutls_record_overhead_size() +3.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.1.2
session: is a gnutls_session_t type.
flags: should be zero
This function replies to a ping by sending a pong to the peer.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.1.2
session: is a gnutls_session_t type.
retrans_timeout: The time at which a retransmission will occur in milliseconds
total_timeout: The time at which the connection will be aborted, in milliseconds.
This function will override the timeouts for the DTLS heartbeat
protocol. The retransmission timeout is the time after which a
message from the peer is not received, the previous request will
be retransmitted. The total timeout is the time after which the
handshake will be aborted with GNUTLS_E_TIMEDOUT .
Since: 3.1.2
hex_data: string with data in hex format
hex_size: size of hex data
bin_data: output array with binary data
bin_size: when calling should hold maximum size of bin_data ,
on return will hold actual length of bin_data .
Convert a buffer with hex data to binary data. This function
unlike gnutls_hex_decode() can parse hex data with separators
between numbers. That is, it ignores any non-hex characters.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 2.4.0
hex_data: contain the encoded data
result: the place where decoded data will be copied
result_size: holds the size of the result
This function will decode the given encoded data, using the hex encoding used by PSK password files.
Initially result_size must hold the maximum size available in
result , and on return it will contain the number of bytes written.
Returns: GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
long enough, GNUTLS_E_PARSING_ERROR on invalid hex data, or 0 on success.
hex_data: contain the encoded data
result: the result in an allocated string
This function will decode the given encoded data, using the hex encoding used by PSK password files.
Returns: GNUTLS_E_PARSING_ERROR on invalid hex data, or 0 on success.
data: contain the raw data
result: the place where hex data will be copied
result_size: holds the size of the result
This function will convert the given data to printable data, using the hex encoding, as used in the PSK password files.
Note that the size of the result includes the null terminator.
Returns: GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
long enough, or 0 on success.
data: contain the raw data
result: the result in an allocated string
This function will convert the given data to printable data, using the hex encoding, as used in the PSK password files.
Note that the size of the result does NOT include the null terminator.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
input: contain the UTF-8 formatted domain name
ilen: the length of the provided string
out: the result in an null-terminated allocated string
flags: should be zero
This function will convert the provided UTF-8 domain name, to its IDNA mapping in an allocated variable. Note that depending on the flags the used gnutls library was compiled with, the output of this function may vary (i.e., may be IDNA2008, or IDNA2003).
To force IDNA2008 specify the flag GNUTLS_IDNA_FORCE_2008 . In
the case GnuTLS is not compiled with the necessary dependencies,
GNUTLS_E_UNIMPLEMENTED_FEATURE will be returned to indicate that
gnutls is unable to perform the requested conversion.
Note also, that this function will return an empty string if an empty string is provided as input.
Returns: GNUTLS_E_INVALID_UTF8_STRING on invalid UTF-8 data, or 0 on success.
Since: 3.5.8
input: contain the ACE (IDNA) formatted domain name
ilen: the length of the provided string
out: the result in an null-terminated allocated UTF-8 string
flags: should be zero
This function will convert an ACE (ASCII-encoded) domain name to a UTF-8 domain name.
If GnuTLS is compiled without IDNA support, then this function
will return GNUTLS_E_UNIMPLEMENTED_FEATURE .
Note also, that this function will return an empty string if an empty string is provided as input.
Returns: A negative error code on error, or 0 on success.
Since: 3.5.8
session: is a pointer to a gnutls_session_t type.
flags: indicate if this session is to be used for server or client.
This function initializes the provided session. Every session must
be initialized before use, and after successful initialization and
use must be deinitialized by calling gnutls_deinit() .
flags can be any combination of flags from gnutls_init_flags_t .
Note that since version 3.1.2 this function enables some common
TLS extensions such as session tickets and OCSP certificate status
request in client side by default. To prevent that use the GNUTLS_NO_DEFAULT_EXTENSIONS
flag.
Note that it is never mandatory to use gnutls_deinit() after this
function fails. Since gnutls 3.8.0, it is safe to unconditionally
use gnutls_deinit() even after failure regardless of whether the
memory was initialized prior to gnutls_init() ; however, clients
wanting to be portable to older versions of the library should
either skip deinitialization on failure, or pre-initialize the
memory passed in to gnutls_init() to all zeroes via memset() or
similar.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
key: is a pointer to a gnutls_datum_t which will contain a newly
created key
key_size: the number of bytes of the key
Generates a random key of key_size bytes.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
Since: 3.0
session: is a gnutls_session_t type.
Get the currently used key exchange algorithm.
This function will return GNUTLS_KX_ECDHE_RSA , or GNUTLS_KX_DHE_RSA
under TLS 1.3, to indicate an elliptic curve DH key exchange or
a finite field one. The precise group used is available
by calling gnutls_group_get() instead.
Returns: the key exchange algorithm used in the last handshake, a
gnutls_kx_algorithm_t value.
name: is a KX name
Convert a string to a gnutls_kx_algorithm_t value. The names are
compared in a case insensitive way.
Returns: an id of the specified KX algorithm, or GNUTLS_KX_UNKNOWN
on error.
algorithm: is a key exchange algorithm
Convert a gnutls_kx_algorithm_t value to a string.
Returns: a pointer to a string that contains the name of the
specified key exchange algorithm, or NULL .
Get a list of supported key exchange algorithms.
This function is not thread safe.
Returns: a (0)-terminated list of gnutls_kx_algorithm_t integers
indicating the available key exchange algorithms.
filename: the name of the file to load
data: Where the file will be stored
This function will load a file into a datum. The data are
zero terminated but the terminating null is not included in length.
The returned data are allocated using gnutls_malloc() .
Note that this function is not designed for reading sensitive materials, such as private keys, on practical applications. When the reading fails in the middle, the partially loaded content might remain on memory.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since 3.1.0
session: is a gnutls_session_t type.
Get the currently used MAC algorithm.
Returns: the currently used mac algorithm, a
gnutls_mac_algorithm_t value.
name: is a MAC algorithm name
Convert a string to a gnutls_mac_algorithm_t value. The names are
compared in a case insensitive way.
Returns: a gnutls_mac_algorithm_t id of the specified MAC
algorithm string, or GNUTLS_MAC_UNKNOWN on failure.
algorithm: is an encryption algorithm
Returns the size of the MAC key used in TLS.
Returns: length (in bytes) of the given MAC key size, or 0 if the given MAC algorithm is invalid.
algorithm: is a MAC algorithm
Convert a gnutls_mac_algorithm_t value to a string.
Returns: a string that contains the name of the specified MAC
algorithm, or NULL .
Get a list of hash algorithms for use as MACs. Note that not necessarily all MACs are supported in TLS cipher suites. This function is not thread safe.
Returns: Return a (0)-terminated list of gnutls_mac_algorithm_t
integers indicating the available MACs.
s1: the first address to compare
s2: the second address to compare
n: the size of memory to compare
This function will operate similarly to memcmp() , but will operate
on time that depends only on the size of the string. That is will
not return early if the strings don’t match on the first byte.
Returns: non zero on difference and zero if the buffers are identical.
Since: 3.4.0
data: the memory to set
c: the constant byte to fill the memory with
size: the size of memory
This function will operate similarly to memset() , but will
not be optimized out by the compiler.
Since: 3.4.0
session: is a gnutls_session_t type.
responder_id: ignored, must be NULL
responder_id_size: ignored, must be zero
extensions: ignored, must be NULL
This function is to be used by clients to request OCSP response from the server, using the "status_request" TLS extension. Only OCSP status type is supported.
Previous versions of GnuTLS supported setting responder_id and
extensions fields, but due to the difficult semantics of the
parameter usage, and other issues, this support was removed
since 3.6.0 and these parameters must be set to NULL .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.1.3
session: is a gnutls_session_t type.
response: a gnutls_datum_t with DER encoded OCSP response
This function returns the OCSP status response received
from the TLS server. The response should be treated as
constant. If no OCSP response is available then
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.1.3
session: is a gnutls_session_t type.
idx: the index of peer’s certificate
response: a gnutls_datum_t with DER encoded OCSP response
This function returns the OCSP status response received
from the TLS server for the certificate index provided.
The index corresponds to certificates as returned by
gnutls_certificate_get_peers. When index is zero this
function operates identically to gnutls_ocsp_status_request_get() .
The returned response should be treated as
constant. If no OCSP response is available for the
given index then GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
is returned.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.6.3
session: is a gnutls session
flags: should be zero or GNUTLS_OCSP_SR_IS_AVAIL
When flags are zero this function returns non-zero if a valid OCSP status response was included in the TLS handshake. That is, an OCSP status response which is not too old, superseded or marks the certificate as revoked. It returns zero otherwise.
When the flag GNUTLS_OCSP_SR_IS_AVAIL is specified, the function
returns non-zero if an OCSP status response was included in the handshake
even if it was invalid. Otherwise, if no OCSP status response was included,
it returns zero. The GNUTLS_OCSP_SR_IS_AVAIL flag was introduced in GnuTLS 3.4.0.
This is a helper function when needing to decide whether to perform an explicit OCSP validity check on the peer’s certificate. Should be called after any of gnutls_certificate_verify_peers*() are called.
This function is always usable on client side, but on server side only under TLS 1.3, which is the first version of TLS that allows cliend-side OCSP responses.
Returns: Non-zero if the response was valid, or a zero if it wasn’t sent, or sent and was invalid.
Since: 3.1.4
oid: is an object identifier
Converts a textual object identifier to a gnutls_digest_algorithm_t value.
Returns: a gnutls_digest_algorithm_t id of the specified digest
algorithm, or GNUTLS_DIG_UNKNOWN on failure.
Since: 3.4.3
oid: is a curve’s OID
Returns: return a gnutls_ecc_curve_t value corresponding to
the specified OID, or GNUTLS_ECC_CURVE_INVALID on error.
Since: 3.4.3
oid: is an object identifier
Converts a textual object identifier to a gnutls_gost_paramset_t value.
Returns: a gnutls_gost_paramset_get_oid of the specified GOST 28147
param st, or GNUTLS_GOST_PARAMSET_UNKNOWN on failure.
Since: 3.6.3
oid: is an object identifier
Converts a textual object identifier typically from PKCS5 values to a gnutls_mac_algorithm_t value.
Returns: a gnutls_mac_algorithm_t id of the specified digest
algorithm, or GNUTLS_MAC_UNKNOWN on failure.
Since: 3.5.4
oid: is an object identifier
Converts a textual object identifier to a gnutls_pk_algorithm_t value.
Returns: a gnutls_pk_algorithm_t id of the specified digest
algorithm, or GNUTLS_PK_UNKNOWN on failure.
Since: 3.4.3
oid: is an object identifier
Converts a textual object identifier to a gnutls_sign_algorithm_t value.
Returns: a gnutls_sign_algorithm_t id of the specified digest
algorithm, or GNUTLS_SIGN_UNKNOWN on failure.
Since: 3.4.3
session: is a gnutls session
status: is ignored
This function is no-op.
Returns: GNUTLS_E_UNIMPLEMENTED_FEATURE .
packet: is a pointer to a gnutls_packet_st structure.
This function will deinitialize all data associated with the received packet.
Since: 3.3.5
packet: is a gnutls_packet_t type.
data: will contain the data present in the packet structure (may be NULL )
sequence: the 8-bytes of the packet sequence number (may be NULL )
This function returns the data and sequence number associated with the received packet.
Since: 3.3.5
header: A null terminated string with the PEM header (eg. CERTIFICATE)
b64_data: contain the encoded data
result: the place where decoded data will be copied
result_size: holds the size of the result
This function will decode the given encoded data. If the header
given is non NULL this function will search for "—–BEGIN header"
and decode only this part. Otherwise it will decode the first PEM
packet found.
Returns: On success GNUTLS_E_SUCCESS (0) is returned,
GNUTLS_E_SHORT_MEMORY_BUFFER is returned if the buffer given is
not long enough, or 0 on success.
header: The PEM header (eg. CERTIFICATE)
b64_data: contains the encoded data
result: the location of decoded data
This function will decode the given encoded data. The decoded data will be allocated, and stored into result. If the header given is non null this function will search for "—–BEGIN header" and decode only this part. Otherwise it will decode the first PEM packet found.
You should use gnutls_free() to free the returned data.
Note, that prior to GnuTLS 3.4.0 this function was available
under the name gnutls_pem_base64_decode_alloc() . There is
compatibility macro pointing to this function.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.4.0
msg: is a message to be put in the header (may be NULL )
data: contain the raw data
result: the place where base64 data will be copied
result_size: holds the size of the result
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages.
The output string will be null terminated, although the output size will not include the terminating null.
Returns: On success GNUTLS_E_SUCCESS (0) is returned,
GNUTLS_E_SHORT_MEMORY_BUFFER is returned if the buffer given is
not long enough, or 0 on success.
header: is a message to be put in the encoded header (may be NULL )
data: contains the raw data
result: will hold the newly allocated encoded data
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages. This function will allocate the required memory to hold the encoded data.
You should use gnutls_free() to free the returned data.
Note, that prior to GnuTLS 3.4.0 this function was available
under the name gnutls_pem_base64_encode_alloc() . There is
compatibility macro pointing to this function.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.4.0
error: is a GnuTLS error code, a negative error code
This function is like perror() . The only difference is that it
accepts an error number returned by a gnutls function.
algorithm: is a pk algorithm
Convert a gnutls_pk_algorithm_t value to a string.
Returns: a string that contains the name of the specified public
key algorithm, or NULL .
algo: is a public key algorithm
bits: is the number of bits
This is the inverse of gnutls_sec_param_to_pk_bits() . Given an algorithm
and the number of bits, it will return the security parameter. This is
a rough indication.
Returns: The security parameter.
Since: 2.12.0
name: is a string containing a public key algorithm name.
Convert a string to a gnutls_pk_algorithm_t value. The names are
compared in a case insensitive way. For example,
gnutls_pk_get_id("RSA") will return GNUTLS_PK_RSA .
Returns: a gnutls_pk_algorithm_t id of the specified public key
algorithm string, or GNUTLS_PK_UNKNOWN on failures.
Since: 2.6.0
algorithm: is a public key algorithm
Convert a gnutls_pk_algorithm_t value to a string.
Returns: a pointer to a string that contains the name of the
specified public key algorithm, or NULL .
Since: 2.6.0
algorithm: is a public key algorithm
Convert a gnutls_pk_algorithm_t value to its object identifier string.
Returns: a pointer to a string that contains the object identifier of the
specified public key algorithm, or NULL .
Since: 3.4.3
Get a list of supported public key algorithms.
This function is not thread safe.
Returns: a (0)-terminated list of gnutls_pk_algorithm_t integers
indicating the available ciphers.
Since: 2.6.0
pk: is a public key algorithm
hash: a hash algorithm
This function maps public key and hash algorithms combinations to signature algorithms.
Returns: return a gnutls_sign_algorithm_t value, or GNUTLS_SIGN_UNKNOWN on error.
session: is a gnutls_session_t type.
label_size: length of the label variable.
label: label used in PRF computation, typically a short string.
server_random_first: non-zero if server random field should be first in seed
extra_size: length of the extra variable.
extra: optional extra data to seed the PRF with.
outsize: size of pre-allocated output buffer to hold the output.
out: pre-allocated buffer to hold the generated data.
Applies the TLS Pseudo-Random-Function (PRF) on the master secret
and the provided data, seeded with the client and server random fields.
For the key expansion specified in RFC5705 see gnutls_prf_rfc5705() .
The label variable usually contains a string denoting the purpose
for the generated data. The server_random_first indicates whether
the client random field or the server random field should be first
in the seed. Non-zero indicates that the server random field is first,
0 that the client random field is first.
The extra variable can be used to add more data to the seed, after
the random variables. It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
The output is placed in out , which must be pre-allocated.
Note: This function produces identical output with gnutls_prf_rfc5705()
when server_random_first is set to 0 and extra is NULL . Under TLS1.3
this function will only operate when these conditions are true, or otherwise
return GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS on success, or an error code.
session: is a gnutls_session_t type.
label_size: length of the label variable.
label: label used in PRF computation, typically a short string.
context_size: length of the extra variable.
context: optional extra data to seed the PRF with.
outsize: size of pre-allocated output buffer to hold the output.
out: pre-allocated buffer to hold the generated data.
This function is similar to gnutls_prf_rfc5705() , but only works in
TLS 1.3 or later to export early keying material.
Note that the keying material is only available after the
ClientHello message is processed and before the application traffic
keys are established. Therefore this function shall be called in a
handshake hook function for GNUTLS_HANDSHAKE_CLIENT_HELLO .
The label variable usually contains a string denoting the purpose
for the generated data.
The context variable can be used to add more data to the seed, after
the random variables. It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
The output is placed in out , which must be pre-allocated.
Note that, to provide the RFC5705 context, the context variable
must be non-null.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since: 3.6.8
session: is a gnutls_session_t type.
Get the currently used hash algorithm. In TLS 1.3, the hash algorithm is used for both the key derivation function and handshake message authentication code. In TLS 1.2, it matches the hash algorithm used for PRF.
Returns: the currently used hash algorithm, a
gnutls_digest_algorithm_t value.
Since: 3.6.13
session: is a gnutls_session_t type.
label_size: length of the label variable.
label: label used in PRF computation, typically a short string.
seed_size: length of the seed variable.
seed: optional extra data to seed the PRF with.
outsize: size of pre-allocated output buffer to hold the output.
out: pre-allocated buffer to hold the generated data.
Apply the TLS Pseudo-Random-Function (PRF) on the master secret and the provided data.
The label variable usually contains a string denoting the purpose
for the generated data. The seed usually contains data such as the
client and server random, perhaps together with some additional
data that is added to guarantee uniqueness of the output for a
particular purpose.
Because the output is not guaranteed to be unique for a particular
session unless seed includes the client random and server random
fields (the PRF would output the same data on another connection
resumed from the first one), it is not recommended to use this
function directly. The gnutls_prf() function seeds the PRF with the
client and server random fields directly, and is recommended if you
want to generate pseudo random data unique for each session.
Note: This function will only operate under TLS versions prior to 1.3.
In TLS1.3 the use of PRF is replaced with HKDF and the generic
exporters like gnutls_prf_rfc5705() should be used instead. Under
TLS1.3 this function returns GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS on success, or an error code.
session: is a gnutls_session_t type.
label_size: length of the label variable.
label: label used in PRF computation, typically a short string.
context_size: length of the extra variable.
context: optional extra data to seed the PRF with.
outsize: size of pre-allocated output buffer to hold the output.
out: pre-allocated buffer to hold the generated data.
Exports keying material from TLS/DTLS session to an application, as specified in RFC5705.
In the TLS versions prior to 1.3, it applies the TLS Pseudo-Random-Function (PRF) on the master secret and the provided data, seeded with the client and server random fields.
In TLS 1.3, it applies HKDF on the exporter master secret derived from the master secret.
The label variable usually contains a string denoting the purpose
for the generated data.
The context variable can be used to add more data to the seed, after
the random variables. It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
The output is placed in out , which must be pre-allocated.
Note that, to provide the RFC5705 context, the context variable
must be non-null.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since: 3.4.4
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available certificate types in the priority structure.
As of version 3.6.4 this function is an alias for
gnutls_priority_certificate_type_list2 with the target parameter
set to:
- GNUTLS_CTYPE_SERVER, if the SERVER_PRECEDENCE option is set
- GNUTLS_CTYPE_CLIENT, otherwise.
Returns: the number of certificate types, or an error code.
Since: 3.0
pcache: is a gnutls_priority_t type.
list: will point to an integer list.
target: is a gnutls_ctype_target_t type. Valid arguments are
GNUTLS_CTYPE_CLIENT and GNUTLS_CTYPE_SERVER
Get a list of available certificate types for the given target in the priority structure.
Returns: the number of certificate types, or an error code.
Since: 3.6.4
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available ciphers in the priority structure.
Returns: the number of items, or an error code.
Since: 3.2.3
priority_cache: is a gnutls_priority_t type.
Deinitializes the priority cache.
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available elliptic curves in the priority structure.
Deprecated: This function has been replaced by
gnutls_priority_group_list() since 3.6.0.
Returns: the number of items, or an error code.
Since: 3.0
pcache: is a gnutls_priority_t type.
idx: is an index number.
sidx: internal index of cipher suite to get information about.
Provides the internal ciphersuite index to be used with
gnutls_cipher_suite_info() . The index idx provided is an
index kept at the priorities structure. It might be that a valid
priorities index does not correspond to a ciphersuite and in
that case GNUTLS_E_UNKNOWN_CIPHER_SUITE will be returned.
Once the last available index is crossed then
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
Returns: On success it returns GNUTLS_E_SUCCESS (0), or a negative error value otherwise.
Since: 3.0.9
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available groups in the priority structure.
Returns: the number of items, or an error code.
Since: 3.6.0
priority_cache: is a gnutls_priority_t type.
priorities: is a string describing priorities (may be NULL )
err_pos: In case of an error this will have the position in the string the error occurred
For applications that do not modify their crypto settings per release, consider
using gnutls_priority_init2() with GNUTLS_PRIORITY_INIT_DEF_APPEND flag
instead. We suggest to use centralized crypto settings handled by the GnuTLS
library, and applications modifying the default settings to their needs.
This function is identical to gnutls_priority_init2() with zero
flags.
A NULL priorities string indicates the default priorities to be
used (this is available since GnuTLS 3.3.0).
Returns: On syntax error GNUTLS_E_INVALID_REQUEST is returned,
GNUTLS_E_SUCCESS on success, or an error code.
priority_cache: is a gnutls_priority_t type.
priorities: is a string describing priorities (may be NULL )
err_pos: In case of an error this will have the position in the string the error occurred
flags: zero or GNUTLS_PRIORITY_INIT_DEF_APPEND
Sets priorities for the ciphers, key exchange methods, and macs.
The priority_cache should be deinitialized
using gnutls_priority_deinit() .
The priorities option allows you to specify a colon
separated list of the cipher priorities to enable.
Some keywords are defined to provide quick access
to common preferences.
When flags is set to GNUTLS_PRIORITY_INIT_DEF_APPEND then the priorities specified will be appended to the default options.
Unless there is a special need, use the "NORMAL" keyword to apply a reasonable security level, or "NORMAL:%COMPAT" for compatibility.
"PERFORMANCE" means all the "secure" ciphersuites are enabled, limited to 128 bit ciphers and sorted by terms of speed performance.
"LEGACY" the NORMAL settings for GnuTLS 3.2.x or earlier. There is no verification profile set, and the allowed DH primes are considered weak today.
"NORMAL" means all "secure" ciphersuites. The 256-bit ciphers are included as a fallback only. The ciphers are sorted by security margin.
"PFS" means all "secure" ciphersuites that support perfect forward secrecy. The 256-bit ciphers are included as a fallback only. The ciphers are sorted by security margin.
"SECURE128" means all "secure" ciphersuites of security level 128-bit or more.
"SECURE192" means all "secure" ciphersuites of security level 192-bit or more.
"SUITEB128" means all the NSA SuiteB ciphersuites with security level of 128.
"SUITEB192" means all the NSA SuiteB ciphersuites with security level of 192.
"NONE" means nothing is enabled. This disables everything, including protocols.
"@KEYWORD1,KEYWORD2,..." The system administrator imposed settings.
The provided keyword(s) will be expanded from a configuration-time
provided file - default is: /etc/gnutls/config.
Any attributes that follow it, will be appended to the expanded
string. If multiple keywords are provided, separated by commas,
then the first keyword that exists in the configuration file
will be used. At least one of the keywords must exist, or this
function will return an error. Typical usage would be to specify
an application specified keyword first, followed by "SYSTEM" as
a default fallback. e.g., " LIBVIRT ,SYSTEM:!-VERS-SSL3.0" will
first try to find a config file entry matching "LIBVIRT", but if
that does not exist will use the entry for "SYSTEM". If "SYSTEM"
does not exist either, an error will be returned. In all cases,
the SSL3.0 protocol will be disabled. The system priority file
entries should be formatted as "KEYWORD=VALUE", e.g.,
"SYSTEM=NORMAL:+ARCFOUR-128".
Special keywords are "!", "-" and "+". "!" or "-" appended with an algorithm will remove this algorithm. "+" appended with an algorithm will add this algorithm.
Check the GnuTLS manual section "Priority strings" for detailed information.
Examples: "NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL"
"NORMAL:+ARCFOUR-128" means normal ciphers plus ARCFOUR-128.
"SECURE128:-VERS-SSL3.0" means that only secure ciphers are and enabled, SSL3.0 is disabled.
"NONE:+VERS-TLS-ALL:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1",
"NONE:+VERS-TLS-ALL:+AES-128-CBC:+ECDHE-RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1:+CURVE-SECP256R1",
"SECURE256:+SECURE128",
Note that "NORMAL:%COMPAT" is the most compatible mode.
A NULL priorities string indicates the default priorities to be
used (this is available since GnuTLS 3.3.0).
Returns: On syntax error GNUTLS_E_INVALID_REQUEST is returned,
GNUTLS_E_SUCCESS on success, or an error code.
Since: 3.6.3
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available key exchange methods in the priority structure.
Returns: the number of items, or an error code.
Since: 3.2.3
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available MAC algorithms in the priority structure.
Returns: the number of items, or an error code.
Since: 3.2.3
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available TLS version numbers in the priority structure.
Returns: the number of protocols, or an error code.
Since: 3.0
session: is a gnutls_session_t type.
priority: is a gnutls_priority_t type.
Sets the priorities to use on the ciphers, key exchange methods, and macs. Note that this function is expected to be called once per session; when called multiple times (e.g., before a re-handshake, the caller should make sure that any new settings are not incompatible with the original session).
Returns: GNUTLS_E_SUCCESS on success, or an error code on error.
session: is a gnutls_session_t type.
priorities: is a string describing priorities
err_pos: In case of an error this will have the position in the string the error occurred
Sets the priorities to use on the ciphers, key exchange methods,
and macs. This function avoids keeping a
priority cache and is used to directly set string priorities to a
TLS session. For documentation check the gnutls_priority_init() .
To use a reasonable default, consider using gnutls_set_default_priority() ,
or gnutls_set_default_priority_append() instead of this function.
Returns: On syntax error GNUTLS_E_INVALID_REQUEST is returned,
GNUTLS_E_SUCCESS on success, or an error code.
pcache: is a gnutls_priority_t type.
list: will point to an integer list
Get a list of available signature algorithms in the priority structure.
Returns: the number of algorithms, or an error code.
Since: 3.0
iter: an integer counter starting from zero
flags: one of GNUTLS_PRIORITY_LIST_INIT_KEYWORDS , GNUTLS_PRIORITY_LIST_SPECIAL
Can be used to iterate all available priority strings.
Due to internal implementation details, there are cases where this
function can return the empty string. In that case that string should be ignored.
When no strings are available it returns NULL .
Returns: a priority string
Since: 3.4.0
name: is a protocol name
The names are compared in a case insensitive way.
Returns: an id of the specified protocol, or
GNUTLS_VERSION_UNKNOWN on error.
version: is a (gnutls) version number
Convert a gnutls_protocol_t value to a string.
Returns: a string that contains the name of the specified TLS
version (e.g., "TLS1.0"), or NULL .
session: is a gnutls_session_t type.
Get TLS version, a gnutls_protocol_t value.
Returns: The version of the currently used protocol.
Get a list of supported protocols, e.g. SSL 3.0, TLS 1.0 etc.
This function is not thread safe.
Returns: a (0)-terminated list of gnutls_protocol_t integers
indicating the available protocols.
version: is a (gnutls) version number
enabled: whether to enable the protocol
Control the previous system-wide setting that marked version as
enabled or disabled. Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
This function is not thread-safe and is intended to be called in the main thread at the beginning of the process execution.
Returns: 0 on success or negative error code otherwise.
Since: 3.7.3
sc: is a pointer to a gnutls_psk_server_credentials_t type.
Allocate a gnutls_psk_client_credentials_t structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
sc: is a pointer to a gnutls_psk_server_credentials_t type.
Allocate a gnutls_psk_server_credentials_t structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls session
The PSK identity hint may give the client help in deciding which username to use. This should only be called in case of PSK authentication and in case of a client.
Note: there is no hint in TLS 1.3, so this function will return NULL
if TLS 1.3 has been negotiated.
Returns: the identity hint of the peer, or NULL in case of an error or if TLS 1.3 is being used.
Since: 2.4.0
identity: external identity
context: optional contextual information
version: protocol version to which the PSK is imported
hash: hash algorithm used for KDF
imported_identity: where the imported identity is stored
This formats an external PSK identity identity into an imported
form, described in RFC 9258 as ImportedIdentity.
Upon success, the data field of imported_identity is allocated
using gnutls_malloc() and the caller must free the memory after
use.
Returns: GNUTLS_E_SUCCESS (0) on success, otherwise a negative error code.
Since: 3.8.1
sc: is a gnutls_psk_client_credentials_t type.
Free a gnutls_psk_client_credentials_t structure.
sc: is a gnutls_psk_server_credentials_t type.
Free a gnutls_psk_server_credentials_t structure.
session: is a gnutls session
This should only be called in case of PSK authentication and in case of a server.
The returned pointer should be considered constant (do not free) and valid for the lifetime of the session.
This function will return NULL if the username has embedded NULL bytes.
In that case, gnutls_psk_server_get_username2() should be used to retrieve the username.
Returns: the username of the peer, or NULL in case of an error,
or if the username has embedded NULLs.
session: is a gnutls session
username: a datum that will be filled in by this function
Return a pointer to the username of the peer in the supplied datum. Does not need to be null-terminated.
This should only be called in case of PSK authentication and in case of a server.
The returned pointer should be considered constant (do not free) and valid for the lifetime of the session.
Returns: GNUTLS_E_SUCCESS , or a negative value in case of an error.
res: is a gnutls_psk_client_credentials_t type.
username: is the user’s zero-terminated userid
key: is the user’s key
flags: indicate the format of the key, either
GNUTLS_PSK_KEY_RAW or GNUTLS_PSK_KEY_HEX .
This function sets the username and password, in a
gnutls_psk_client_credentials_t type. Those will be used in
PSK authentication. username should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The key can be either
in raw byte format or in Hex format (without the 0x prefix).
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
res: is a gnutls_psk_client_credentials_t type.
username: is the userid
key: is the user’s key
flags: indicate the format of the key, either
GNUTLS_PSK_KEY_RAW or GNUTLS_PSK_KEY_HEX .
This function is identical to gnutls_psk_set_client_credentials() ,
except that it allows a non-null-terminated username to be introduced.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the username and password for client PSK authentication. The callback’s function form is: int (*callback)(gnutls_session_t, char** username, gnutls_datum_t* key);
The username and key ->data must be allocated using gnutls_malloc() .
The username should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265).
The callback function will be called once per handshake.
The callback function should return 0 on success. -1 indicates an error.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the username and password for client PSK authentication. The callback’s function form is: int (*callback)(gnutls_session_t, gnutls_datum_t* username, gnutls_datum_t* key);
This callback function has the same semantics as that of gnutls_psk_set_client_credentials_function() ,
but it allows non-string usernames to be used.
The username and key ->data must be allocated using gnutls_malloc() .
The username should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265).
The callback function will be called once per handshake.
The callback function should return 0 on success. -1 indicates an error.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the username and password for client PSK authentication. The callback’s function form is: int (*callback)(gnutls_session_t, gnutls_datum_t* username, gnutls_datum_t* key, gnutls_datum_t* context, gnutls_psk_key_flags *flags);
This callback function has the same semantics as that of
gnutls_psk_set_client_credentials_function2() , but it returns flags
associated with the key. The callback may import external PSK
using the method described in RFC 9258 by using
gnutls_psk_format_imported_identity() .
The data field of username , key , and context must be allocated
using gnutls_malloc() . The username should be an ASCII string or
UTF-8 string. In case of a UTF-8 string it is recommended to be
following the PRECIS framework for usernames (rfc8265).
The callback function will be called once per handshake.
The callback function should return 0 on success. -1 indicates an error.
res: is a gnutls_psk_server_credentials_t type
func: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for PSK authentication. The
callback should return GNUTLS_E_SUCCESS (0) on success.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
res: is a gnutls_psk_server_credentials_t type.
password_file: is the PSK password file (passwd.psk)
This function sets the password file, in a
gnutls_psk_server_credentials_t type. This password file
holds usernames and keys and will be used for PSK authentication.
Each entry in the file consists of a username, followed by a colon (’:’) and a hex-encoded key. If the username contains a colon or any other special character, it can be hex-encoded preceded by a ’#’.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the user’s PSK credentials. The callback’s function form is: int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t* key);
username contains the actual username.
The key must be filled in using the gnutls_malloc() .
In case the callback returned a negative number then gnutls will assume that the username does not exist.
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the user’s PSK credentials. The callback’s function form is: int (*callback)(gnutls_session_t, const gnutls_datum_t* username, gnutls_datum_t* key);
This callback function has the same semantics as that of gnutls_psk_set_server_credentials_function() ,
but it allows non-string usernames to be used.
username contains the actual username.
The key must be filled in using the gnutls_malloc() .
In case the callback returned a negative number then gnutls will assume that the username does not exist.
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
cred: is a gnutls_psk_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the user’s PSK credentials. The callback’s function form is: int (*callback)(gnutls_session_t, const gnutls_datum_t* username, gnutls_datum_t* key, gnutls_psk_key_flags *flags);
This callback function has the same semantics as that of
gnutls_psk_set_server_credentials_function2() , but it returns flags
associated with the key. The callback may import external PSK
using the method described in RFC 9258 by using
gnutls_psk_format_imported_identity() .
username contains the actual username.
The key must be filled in using the gnutls_malloc() .
In case the callback returned a negative number then gnutls will assume that the username does not exist.
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
res: is a gnutls_psk_server_credentials_t type.
hint: is the PSK identity hint string
This function sets the identity hint, in a
gnutls_psk_server_credentials_t type. This hint is sent to
the client to help it chose a good PSK credential (i.e., username
and password).
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 2.4.0
res: is a gnutls_psk_server_credentials_t type
dh_params: is a structure that holds Diffie-Hellman parameters.
This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Diffie-Hellman exchange with PSK cipher suites.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
res: is a gnutls_psk_server_credentials_t type
sec_param: is an option of the gnutls_sec_param_t enumeration
This function will set the Diffie-Hellman parameters for a PSK server to use. These parameters will be used in Ephemeral Diffie-Hellman cipher suites and will be selected from the FFDHE set of RFC7919 according to the security level provided.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.5.6
res: is a gnutls_certificate_credentials_t type
func: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman parameters for PSK authentication. The callback
should return GNUTLS_E_SUCCESS (0) on success.
Deprecated: This function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since 3.6.0, DH parameters are negotiated following RFC7919.
type: The type of the random art (for now only GNUTLS_RANDOM_ART_OPENSSH is supported)
key_type: The type of the key (RSA, DSA etc.)
key_size: The size of the key in bits
fpr: The fingerprint of the key
fpr_size: The size of the fingerprint
art: The returned random art
This function will convert a given fingerprint to an "artistic"
image. The returned image is allocated using gnutls_malloc() , is
null-terminated but art->size will not account the terminating null.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type
orig: is the original range provided by the user
next: is the returned range that can be conveyed in a TLS record
remainder: is the returned remaining range
This function should be used when it is required to hide the length
of very long data that cannot be directly provided to gnutls_record_send_range() .
In that case this function should be called with the desired length
hiding range in orig . The returned next value should then be used in
the next call to gnutls_record_send_range() with the partial data.
That process should be repeated until remainder is (0,0).
Returns: 0 in case splitting succeeds, non zero in case of error.
Note that orig is not changed, while the values of next and remainder are modified to store the resulting values.
session: is a gnutls_session_t type.
flags: must be zero
This function performs the post-handshake authentication
for TLS 1.3. The post-handshake authentication is initiated by the server
by calling this function. Clients respond when GNUTLS_E_REAUTH_REQUEST
has been seen while receiving data.
The non-fatal errors expected by this function are:
GNUTLS_E_INTERRUPTED , GNUTLS_E_AGAIN , as well as
GNUTLS_E_GOT_APPLICATION_DATA when called on server side.
The former two interrupt the authentication procedure due to the transport
layer being interrupted, and the latter because there were pending data prior
to peer initiating the re-authentication. The server should read/process that
data as unauthenticated and retry calling gnutls_reauth() .
When this function is called under TLS1.2 or earlier or the peer didn’t
advertise post-handshake auth, it always fails with
GNUTLS_E_INVALID_REQUEST . The verification of the received peers certificate
is delegated to the session or credentials verification callbacks. A
server can check whether post handshake authentication is supported
by the client by checking the session flags with gnutls_session_get_flags() .
Prior to calling this function in server side, the function
gnutls_certificate_server_set_request() must be called setting expectations
for the received certificate (request or require). If none are set
this function will return with GNUTLS_E_INVALID_REQUEST .
Note that post handshake authentication is available irrespective of the initial negotiation type (PSK or certificate). In all cases however, certificate credentials must be set to the session prior to calling this function.
Returns: GNUTLS_E_SUCCESS on a successful authentication, otherwise a negative error code.
session: is a gnutls_session_t type.
If the session supports length-hiding padding, you can
invoke gnutls_record_send_range() to send a message whose
length is hidden in the given range. If the session does not
support length hiding padding, you can use the standard
gnutls_record_send() function, or gnutls_record_send_range()
making sure that the range is the same as the length of the
message you are trying to send.
Returns: true (1) if the current session supports length-hiding padding, false (0) if the current session does not.
session: is a gnutls_session_t type.
This function checks if there pending corked
data in the gnutls buffers –see gnutls_record_cork() .
Returns: Returns the size of the corked data or zero.
Since: 3.2.8
session: is a gnutls_session_t type.
This function checks if there are unread data
in the gnutls buffers. If the return value is
non-zero the next call to gnutls_record_recv()
is guaranteed not to block.
Returns: Returns the size of the data or zero.
session: is a gnutls_session_t type.
If called, gnutls_record_send() will no longer send any records.
Any sent records will be cached until gnutls_record_uncork() is called.
This function is safe to use with DTLS after GnuTLS 3.3.0.
Since: 3.1.9
session: is a gnutls_session_t type.
Used to disabled padding in TLS 1.0 and above. Normally you do not need to use this function, but there are buggy clients that complain if a server pads the encrypted data. This of course will disable protection against statistical attacks on the data.
This function is defunct since 3.1.7. Random padding is disabled
by default unless requested using gnutls_record_send_range() .
session: is a gnutls_session_t type.
This function discards all queued to be sent packets in a DTLS session.
These are the packets queued after an interrupted gnutls_record_send() .
This function can only be used with transports where send() is
an all-or-nothing operation (e.g., UDP). When partial writes are allowed
this function will cause session errors.
Returns: The number of bytes discarded.
Since: 3.4.0
session: is a gnutls_session_t type.
This function is useful to determine whether a GnuTLS function was interrupted
while sending or receiving, so that select() or poll() may be called appropriately.
It provides information about the internals of the record
protocol and is only useful if a prior gnutls function call,
e.g. gnutls_handshake() , was interrupted and returned
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN . After such an interrupt
applications may call select() or poll() before restoring the
interrupted GnuTLS function.
This function’s output is unreliable if you are using the same
session in different threads for sending and receiving.
Returns: 0 if interrupted while trying to read data, or 1 while trying to write data.
session: is a gnutls_session_t type.
This function returns the maximum early data size in this connection. This property can only be set to servers. The client may be provided with the maximum allowed size through the "early_data" extension of the NewSessionTicket handshake message.
Returns: The maximum early data size in this connection.
Since: 3.6.5
session: is a gnutls_session_t type.
Get the record size. The maximum record size is negotiated by the client after the first handshake message.
Returns: The maximum record packet size in this connection.
session: is a gnutls_session_t type
read: if non-zero the read parameters are returned, otherwise the write
mac_key: the key used for MAC (if a MAC is used)
IV: the initialization vector or nonce used
cipher_key: the cipher key
seq_number: A 64-bit sequence number
This function will return the parameters of the current record state. These are only useful to be provided to an external off-loading device or subsystem. The returned values should be considered constant and valid for the lifetime of the session.
In that case, to sync the state back you must call gnutls_record_set_state() .
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since 3.4.0
session: is gnutls_session_t
This function will return the size in bytes of the overhead due to TLS (or DTLS) per record. On certain occasions (e.g., CBC ciphers) the returned value is the maximum possible overhead.
Since: 3.2.2
session: is a gnutls_session_t type.
data: the buffer that the data will be read into
data_size: the number of requested bytes
This function has the similar semantics with recv() . The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
In the special case that the peer requests a renegotiation, the
caller will receive an error code of GNUTLS_E_REHANDSHAKE . In case
of a client, this message may be simply ignored, replied with an alert
GNUTLS_A_NO_RENEGOTIATION , or replied with a new handshake,
depending on the client’s will. A server receiving this error code
can only initiate a new handshake or terminate the session.
If EINTR is returned by the internal pull function (the default
is recv() ) then GNUTLS_E_INTERRUPTED will be returned. If
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN is returned, you must
call this function again to get the data. See also
gnutls_record_get_direction() .
Returns: The number of bytes received and zero on EOF (for stream
connections). A negative error code is returned in case of an error.
The number of bytes received might be less than the requested data_size .
session: is a gnutls_session_t type.
data: the buffer that the data will be read into
data_size: the number of requested bytes
This function can be used by a server to retrieve data sent early
in the handshake processes when resuming a session. This is used
to implement a zero-roundtrip (0-RTT) mode. It has the same
semantics as gnutls_record_recv() .
This function can be called either in a handshake hook, or after the handshake is complete.
Returns: The number of bytes received and zero when early data
reading is complete. A negative error code is returned in case of
an error. If no early data is received during the handshake, this
function returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE . The
number of bytes received might be less than the requested
data_size .
Since: 3.6.5
session: is a gnutls_session_t type.
packet: the structure that will hold the packet data
This is a lower-level function than gnutls_record_recv() and allows
to directly receive the whole decrypted packet. That avoids a
memory copy, and is intended to be used by applications seeking high
performance.
The received packet is accessed using gnutls_packet_get() and
must be deinitialized using gnutls_packet_deinit() . The returned
packet will be NULL if the return value is zero (EOF).
Returns: The number of bytes received and zero on EOF (for stream connections). A negative error code is returned in case of an error.
Since: 3.3.5
session: is a gnutls_session_t type.
data: the buffer that the data will be read into
data_size: the number of requested bytes
seq: is the packet’s 64-bit sequence number. Should have space for 8 bytes.
This function is the same as gnutls_record_recv() , except that
it returns in addition to data, the sequence number of the data.
This is useful in DTLS where record packets might be received
out-of-order. The returned 8-byte sequence number is an
integer in big-endian format and should be
treated as a unique message identification.
Returns: The number of bytes received and zero on EOF. A negative
error code is returned in case of an error. The number of bytes
received might be less than data_size .
Since: 3.0
session: is a gnutls_session_t type.
data: contains the data to send
data_size: is the length of the data
This function has the similar semantics with send() . The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
Note that if the send buffer is full, send() will block this
function. See the send() documentation for more information.
You can replace the default push function which is send() , by using
gnutls_transport_set_push_function() .
If the EINTR is returned by the internal push function
then GNUTLS_E_INTERRUPTED will be returned. If
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN is returned, you must
call this function again with the exact same parameters, or provide a
NULL pointer for data and 0 for data_size , in order to write the
same data as before. If you wish to discard the previous data instead
of retrying, you must call gnutls_record_discard_queued() before
calling this function with different parameters. Note that the latter
works only on special transports (e.g., UDP).
cf. gnutls_record_get_direction() .
Note that in DTLS this function will return the GNUTLS_E_LARGE_PACKET
error code if the send data exceed the data MTU value - as returned
by gnutls_dtls_get_data_mtu() . The errno value EMSGSIZE
also maps to GNUTLS_E_LARGE_PACKET .
Note that since 3.2.13 this function can be called under cork in DTLS
mode, and will refuse to send data over the MTU size by returning
GNUTLS_E_LARGE_PACKET .
Returns: The number of bytes sent, or a negative error code. The
number of bytes sent might be less than data_size . The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
session: is a gnutls_session_t type.
data: contains the data to send
data_size: is the length of the data
pad: padding to be added to the record
flags: must be zero
This function is identical to gnutls_record_send() except that it
takes an extra argument to specify padding to be added the record.
To determine the maximum size of padding, use
gnutls_record_get_max_size() and gnutls_record_overhead_size() .
Note that in order for GnuTLS to provide constant time processing
of padding and data in TLS1.3, the flag GNUTLS_SAFE_PADDING_CHECK
must be used in gnutls_init() .
Returns: The number of bytes sent, or a negative error code. The
number of bytes sent might be less than data_size . The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
Since: 3.6.3
session: is a gnutls_session_t type.
data: contains the data to send
data_size: is the length of the data
This function can be used by a client to send data early in the
handshake processes when resuming a session. This is used to
implement a zero-roundtrip (0-RTT) mode. It has the same semantics
as gnutls_record_send() .
There may be a limit to the amount of data sent as early data. Use
gnutls_record_get_max_early_data_size() to check the limit. If the
limit exceeds, this function returns
GNUTLS_E_RECORD_LIMIT_REACHED .
Returns: The number of bytes sent, or a negative error code. The
number of bytes sent might be less than data_size . The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
Since: 3.6.5
session: is a gnutls_session_t type.
fd: file descriptor from which to read data.
offset: Is relative to file offset, denotes the starting location for reading. after function returns, it point to position following last read byte.
count: is the length of the data in bytes to be read from file and send.
This function sends data from fd . If KTLS (kernel TLS) is enabled, it will
use the sendfile() system call to avoid overhead of copying data between user
space and the kernel. Otherwise, this functionality is merely emulated by
calling read() and gnutls_record_send() . If this implementation is
suboptimal, check whether KTLS is enabled using
gnutls_transport_is_ktls_enabled() .
If offset is NULL then file offset is incremented by number of bytes send,
otherwise file offset remains unchanged.
Returns: The number of bytes sent, or a negative error code.
session: is a gnutls_session_t type.
data: contains the data to send.
data_size: is the length of the data.
range: is the range of lengths in which the real data length must be hidden.
This function operates like gnutls_record_send() but, while
gnutls_record_send() adds minimal padding to each TLS record,
this function uses the TLS extra-padding feature to conceal the real
data size within the range of lengths provided.
Some TLS sessions do not support extra padding (e.g. stream ciphers in standard
TLS or SSL3 sessions). To know whether the current session supports extra
padding, and hence length hiding, use the gnutls_record_can_use_length_hiding()
function.
Note: This function currently is limited to blocking sockets.
Returns: The number of bytes sent (that is data_size in a successful invocation), or a negative error code.
session: is a gnutls_session_t type.
size: is the new size
This function sets the maximum early data size in this connection. This property can only be set to servers. The client may be provided with the maximum allowed size through the "early_data" extension of the NewSessionTicket handshake message.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.6.4
session: is a gnutls_session_t type.
size: is the new size
This function sets the maximum amount of plaintext received in a record in this connection.
The limit is also negotiated through a TLS extension called ’record size limit’. Note that while the ’record size limit’ extension is preferred, not all TLS implementations use or even understand the extension.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since: 3.6.8
session: is a gnutls_session_t type.
size: is the new size
This function sets the maximum amount of plaintext sent and received in a record in this connection.
Prior to 3.6.4, this function was implemented using a TLS extension called ’max fragment length’, which limits the acceptable values to 512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12).
Since 3.6.4, the limit is also negotiated through a new TLS extension called ’record size limit’, which doesn’t have the limitation, as long as the value ranges between 512 and 16384. Note that while the ’record size limit’ extension is preferred, not all TLS implementations use or even understand the extension.
Deprecated: if the client can assume that the ’record size limit’
extension is supported by the server, we recommend using
gnutls_record_set_max_recv_size() instead.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
session: is a gnutls_session_t type
read: if non-zero the read parameters are returned, otherwise the write
seq_number: A 64-bit sequence number
This function will set the sequence number in the current record state.
This function is useful if sending and receiving are offloaded from
gnutls. That is, if gnutls_record_get_state() was used.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since 3.4.0
session: is a gnutls_session_t type.
ms: is a timeout value in milliseconds
This function sets the receive timeout for the record layer
to the provided value. Use an ms value of zero to disable
timeout (the default), or GNUTLS_INDEFINITE_TIMEOUT , to
set an indefinite timeout.
This function requires to set a pull timeout callback. See
gnutls_transport_set_pull_timeout_function() .
Since: 3.1.7
session: is a gnutls_session_t type.
flags: Could be zero or GNUTLS_RECORD_WAIT
This resets the effect of gnutls_record_cork() , and flushes any pending
data. If the GNUTLS_RECORD_WAIT flag is specified then this
function will block until the data is sent or a fatal error
occurs (i.e., the function will retry on GNUTLS_E_AGAIN and
GNUTLS_E_INTERRUPTED ).
If the flag GNUTLS_RECORD_WAIT is not specified and the function
is interrupted then the GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED
errors will be returned. To obtain the data left in the corked
buffer use gnutls_record_check_corked() .
Returns: On success the number of transmitted data is returned, or otherwise a negative error code.
Since: 3.1.9
session: is a gnutls_session_t type.
This function can only be called in server side, and instructs a TLS 1.2 or earlier client to renegotiate parameters (perform a handshake), by sending a hello request message.
If this function succeeds, the calling application
should call gnutls_record_recv() until GNUTLS_E_REHANDSHAKE
is returned to clear any pending data. If the GNUTLS_E_REHANDSHAKE
error code is not seen, then the handshake request was
not followed by the peer (the TLS protocol does not require
the client to do, and such compliance should be handled
by the application protocol).
Once the GNUTLS_E_REHANDSHAKE error code is seen, the
calling application should proceed to calling
gnutls_handshake() to negotiate the new
parameters.
If the client does not wish to renegotiate parameters he
may reply with an alert message, and in that case the return code seen
by subsequent gnutls_record_recv() will be
GNUTLS_E_WARNING_ALERT_RECEIVED with the specific alert being
GNUTLS_A_NO_RENEGOTIATION . A client may also choose to ignore
this request.
Under TLS 1.3 this function is equivalent to gnutls_session_key_update()
with the GNUTLS_KU_PEER flag. In that case subsequent calls to
gnutls_record_recv() will not return GNUTLS_E_REHANDSHAKE , and
calls to gnutls_handshake() in server side are a no-op.
This function always fails with GNUTLS_E_INVALID_REQUEST when
called in client side.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
session: is a gnutls_session_t type.
Can be used to check whether safe renegotiation is being used in the current session.
Returns: 0 when safe renegotiation is not used and non (0) when safe renegotiation is used.
Since: 2.10.0
param: is a security parameter
Convert a gnutls_sec_param_t value to a string.
Returns: a pointer to a string that contains the name of the
specified security level, or NULL .
Since: 2.12.0
algo: is a public key algorithm
param: is a security parameter
When generating private and public key pairs a difficult question is which size of "bits" the modulus will be in RSA and the group size in DSA. The easy answer is 1024, which is also wrong. This function will convert a human understandable security parameter to an appropriate size for the specific algorithm.
Returns: The number of bits, or (0).
Since: 2.12.0
param: is a security parameter
This function will return the number of bits that correspond to symmetric cipher strength for the given security parameter.
Returns: The number of bits, or (0).
Since: 3.3.0
session: is a gnutls_session_t type.
data: will hold the data
data_length: will hold the data length. Must hold the maximum size of data.
type: will hold the server name indicator type
indx: is the index of the server_name
This function will allow you to get the name indication (if any), a client has sent. The name indication may be any of the enumeration gnutls_server_name_type_t.
If type is GNUTLS_NAME_DNS, then this function is to be used by
servers that support virtual hosting, and the data will be a null
terminated IDNA ACE string (prior to GnuTLS 3.4.0 it was a UTF-8 string).
If data has not enough size to hold the server name
GNUTLS_E_SHORT_MEMORY_BUFFER is returned, and data_length will
hold the required size.
indx is used to retrieve more than one server names (if sent by
the client). The first server name has an index of 0, the second 1
and so on. If no name with the given index exists
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, on UTF-8
decoding error GNUTLS_E_IDNA_ERROR is returned, otherwise a negative
error code is returned.
session: is a gnutls_session_t type.
type: specifies the indicator type
name: is a string that contains the server name.
name_length: holds the length of name excluding the terminating null byte
This function is to be used by clients that want to inform (via a TLS extension mechanism) the server of the name they connected to. This should be used by clients that connect to servers that do virtual hosting.
The value of name depends on the type type. In case of
GNUTLS_NAME_DNS , a UTF-8 null-terminated domain name string,
without the trailing dot, is expected.
IPv4 or IPv6 addresses are not permitted to be set by this function.
If the function is called with a name of name_length zero it will clear
all server names set.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
session: is a gnutls_session_t type.
cbtype: an gnutls_channel_binding_t enumeration type
cb: output buffer array with data
Extract given channel binding data of the cbtype (e.g.,
GNUTLS_CB_TLS_UNIQUE ) type.
Returns: GNUTLS_E_SUCCESS on success,
GNUTLS_E_UNIMPLEMENTED_FEATURE if the cbtype is unsupported,
GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE if the data is not
currently available, or an error code.
Since: 2.12.0
session: is a gnutls_session_t type.
This function can be used to disable certain (security) features in TLS in order to maintain maximum compatibility with buggy clients. Because several trade-offs with security are enabled, if required they will be reported through the audit subsystem.
Normally only servers that require maximum compatibility with everything out there, need to call this function.
Note that this function must be called after any call to gnutls_priority functions.
Since: 2.1.4
session: is a gnutls_session_t type.
Get the status of the encrypt-then-mac extension negotiation. This is in accordance to rfc7366
Returns: Non-zero if the negotiation was successful or zero otherwise.
session: is a gnutls_session_t type.
Get the status of the extended master secret extension negotiation.
This is in accordance to RFC7627. That information is also
available to the more generic gnutls_session_get_flags() .
Returns: Non-zero if the negotiation was successful or zero otherwise.
session: the session for which this extension will be set
name: the name of the extension to register
id: the numeric id of the extension
parse_point: the parse type of the extension (see gnutls_ext_parse_type_t)
recv_func: a function to receive the data
send_func: a function to send the data
deinit_func: a function deinitialize any private data
pack_func: a function which serializes the extension’s private data (used on session packing for resumption)
unpack_func: a function which will deserialize the extension’s private data
flags: must be zero or flags from gnutls_ext_flags_t
This function will register a new extension type. The extension will be
only usable within the registered session. If the extension type
is already registered then GNUTLS_E_ALREADY_REGISTERED will be returned,
unless the flag GNUTLS_EXT_FLAG_OVERRIDE_INTERNAL is specified. The latter
flag when specified can be used to override certain extensions introduced
after 3.6.0. It is expected to be used by applications which handle
custom extensions that are not currently supported in GnuTLS, but direct
support for them may be added in the future.
Each registered extension can store temporary data into the gnutls_session_t
structure using gnutls_ext_set_data() , and they can be retrieved using
gnutls_ext_get_data() .
The validity of the extension registered can be given by the appropriate flags
of gnutls_ext_flags_t . If no validity is given, then the registered extension
will be valid for client and TLS1.2 server hello (or encrypted extensions for TLS1.3).
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.5.5
session: is a gnutls_session_t type.
Clears the invalid flag in a session. That means that sessions were corrupt or invalid data were received can be re-used. Use only when debugging or experimenting with the TLS protocol. Should not be used in typical applications.
session: is a gnutls_session_t type.
session_data: is a pointer to space to hold the session.
session_data_size: is the session_data’s size, or it will be set by the function.
Returns all session parameters needed to be stored to support resumption, in a pre-allocated buffer.
See gnutls_session_get_data2() for more information.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type.
data: is a pointer to a datum that will hold the session.
Returns necessary parameters to support resumption. The client
should call this function and store the returned session data. A session
can be resumed later by calling gnutls_session_set_data() with the returned
data. Note that under TLS 1.3, it is recommended for clients to use
session parameters only once, to prevent passive-observers from correlating
the different connections.
The returned data are allocated and must be released using gnutls_free() .
This function will fail if called prior to handshake completion. In case of false start TLS, the handshake completes only after data have been successfully received from the peer.
Under TLS1.3 session resumption is possible only after a session ticket
is received by the client. To ensure that such a ticket has been received use
gnutls_session_get_flags() and check for flag GNUTLS_SFLAGS_SESSION_TICKET ;
if this flag is not set, this function will wait for a new ticket within
an estimated roundtrip, and if not received will return dummy data which
cannot lead to resumption.
To get notified when new tickets are received by the server
use gnutls_handshake_set_hook_function() to wait for GNUTLS_HANDSHAKE_NEW_SESSION_TICKET
messages. Each call of gnutls_session_get_data2() after a ticket is
received, will return session resumption data corresponding to the last
received ticket.
Note that this function under TLS1.3 requires a callback to be set with
gnutls_transport_set_pull_timeout_function() for successful operation. There
was a bug before 3.6.10 which could make this function fail if that callback
was not set. On later versions if not set, the function will return a successful
error code, but will return dummy data that cannot lead to a resumption.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls session
This function returns a string describing the current session.
The string is null terminated and allocated using gnutls_malloc() .
If initial negotiation is not complete when this function is called,
NULL will be returned.
Returns: a description of the protocols and algorithms in the current session.
Since: 3.1.10
session: is a gnutls_session_t type.
This function will return a series (ORed) of flags, applicable for the current session.
This replaces individual informational functions such as
gnutls_safe_renegotiation_status() , gnutls_session_ext_master_secret_status() ,
etc.
Returns: An ORed sequence of flags (see gnutls_session_flags_t )
Since: 3.5.0
session: is a gnutls_session_t type.
session_id: is a pointer to space to hold the session id.
session_id_size: initially should contain the maximum session_id size and will be updated.
Returns the TLS session identifier. The session ID is selected by the server, and in older versions of TLS was a unique identifier shared between client and server which was persistent across resumption. In the latest version of TLS (1.3) or TLS with session tickets, the notion of session identifiers is undefined and cannot be relied for uniquely identifying sessions across client and server.
In client side this function returns the identifier returned by the server, and cannot be assumed to have any relation to session resumption. In server side this function is guaranteed to return a persistent identifier of the session since GnuTLS 3.6.4, which may not necessarily map into the TLS session ID value. Prior to that version the value could only be considered a persistent identifier, under TLS1.2 or earlier and when no session tickets were in use.
The session identifier value returned is always less than
GNUTLS_MAX_SESSION_ID_SIZE .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type.
session_id: will point to the session ID.
Returns the TLS session identifier. The session ID is selected by the server, and in older versions of TLS was a unique identifier shared between client and server which was persistent across resumption. In the latest version of TLS (1.3) or TLS 1.2 with session tickets, the notion of session identifiers is undefined and cannot be relied for uniquely identifying sessions across client and server.
In client side this function returns the identifier returned by the server, and cannot be assumed to have any relation to session resumption. In server side this function is guaranteed to return a persistent identifier of the session since GnuTLS 3.6.4, which may not necessarily map into the TLS session ID value. Prior to that version the value could only be considered a persistent identifier, under TLS1.2 or earlier and when no session tickets were in use.
The session identifier value returned is always less than
GNUTLS_MAX_SESSION_ID_SIZE and should be treated as constant.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.1.4
session: is gnutls_session_t type
This function will return the callback function set using
gnutls_session_set_keylog_function() .
Returns: The function set or NULL otherwise.
Since: 3.6.13
session: is a gnutls_session_t type.
secret: the session’s master secret
This function returns pointers to the master secret used in the TLS session. The pointers are not to be modified or deallocated.
This function is only applicable under TLS 1.2 or earlier versions.
Since: 3.5.0
session: is a gnutls_session_t type.
Get user pointer for session. Useful in callbacks. This is the
pointer set with gnutls_session_set_ptr() .
Returns: the user given pointer from the session structure, or
NULL if it was never set.
session: is a gnutls_session_t type.
client: the client part of the random
server: the server part of the random
This function returns pointers to the client and server random fields used in the TLS handshake. The pointers are not to be modified or deallocated.
If a client random value has not yet been established, the output will be garbage.
Since: 3.0
session: is a gnutls session
This function returns the status of the verification when initiated
via auto-verification, i.e., by gnutls_session_set_verify_cert2() or
gnutls_session_set_verify_cert() . If no certificate verification
was occurred then the return value would be set to ((unsigned int)-1).
The certificate verification status is the same as in gnutls_certificate_verify_peers() .
Returns: the certificate verification status.
Since: 3.4.6
session: is a gnutls_session_t type.
Checks whether session is resumed or not. This is functional for both server and client side.
Returns: non zero if this session is resumed, or a zero if this is a new session.
session: is a gnutls_session_t type.
flags: zero of GNUTLS_KU_PEER
This function will update/refresh the session keys when the
TLS protocol is 1.3 or better. The peer is notified of the
update by sending a message, so this function should be
treated similarly to gnutls_record_send() –i.e., it may
return GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED .
When this flag GNUTLS_KU_PEER is specified, this function
in addition to updating the local keys, will ask the peer to
refresh its keys too.
If the negotiated version is not TLS 1.3 or better this
function will return GNUTLS_E_INVALID_REQUEST .
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.6.3
session: is a gnutls_session_t type.
Check whether the client has asked for session resumption. This function is valid only on server side.
Returns: non zero if session resumption was asked, or a zero if not.
session: is a gnutls_session_t type.
session_data: is a pointer to space to hold the session.
session_data_size: is the session’s size
Sets all session parameters, in order to resume a previously
established session. The session data given must be the one
returned by gnutls_session_get_data() . This function should be
called before gnutls_handshake() .
Keep in mind that session resuming is advisory. The server may choose not to resume the session, thus a full handshake will be performed.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type.
sid: the session identifier
This function sets the session ID to be used in a client hello. This is a function intended for exceptional uses. Do not use this function unless you are implementing a custom protocol.
To set session resumption parameters use gnutls_session_set_data() instead.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.2.1
session: is gnutls_session_t type
func: is the function to be called
This function will set a callback to be called when a new secret is derived and installed during handshake.
Since: 3.6.13
session: is a gnutls_session_t type.
entity: GNUTLS_SERVER or GNUTLS_CLIENT
version: the TLS protocol version
kx: the key exchange method
cipher: the cipher
mac: the MAC algorithm
comp: the compression method (ignored)
master: the master key to use
session_id: the session identifier
This function sets the premaster secret in a session. This is
a function intended for exceptional uses. Do not use this
function unless you are implementing a legacy protocol.
Use gnutls_session_set_data() instead.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
session: is a gnutls_session_t type.
ptr: is the user pointer
This function will set (associate) the user given pointer ptr to
the session structure. This pointer can be accessed with
gnutls_session_get_ptr() .
session: is a gnutls session
hostname: is the expected name of the peer; may be NULL
flags: flags for certificate verification – gnutls_certificate_verify_flags
This function instructs GnuTLS to verify the peer’s certificate
using the provided hostname. If the verification fails the handshake
will also fail with GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR . In that
case the verification result can be obtained using gnutls_session_get_verify_cert_status() .
The hostname pointer provided must remain valid for the lifetime
of the session. More precisely it should be available during any subsequent
handshakes. If no hostname is provided, no hostname verification
will be performed. For a more advanced verification function check
gnutls_session_set_verify_cert2() .
If flags is provided which contain a profile, this function should be
called after any session priority setting functions.
The gnutls_session_set_verify_cert() function is intended to be used by TLS
clients to verify the server’s certificate.
Since: 3.4.6
session: is a gnutls session
data: an array of typed data
elements: the number of data elements
flags: flags for certificate verification – gnutls_certificate_verify_flags
This function instructs GnuTLS to verify the peer’s certificate
using the provided typed data information. If the verification fails the handshake
will also fail with GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR . In that
case the verification result can be obtained using gnutls_session_get_verify_cert_status() .
The acceptable typed data are the same as in gnutls_certificate_verify_peers() ,
and once set must remain valid for the lifetime of the session. More precisely
they should be available during any subsequent handshakes.
If flags is provided which contain a profile, this function should be
called after any session priority setting functions.
Since: 3.4.6
session: is a gnutls_session_t type.
func: is the callback function
This function sets a callback to be called when peer’s certificate
has been received in order to verify it on receipt rather than
doing after the handshake is completed. This overrides any callback
set using gnutls_certificate_set_verify_function() .
The callback’s function prototype is: int (*callback)(gnutls_session_t);
If the callback function is provided then gnutls will call it, in the
handshake, just after the certificate message has been received.
To verify or obtain the certificate the gnutls_certificate_verify_peers2() ,
gnutls_certificate_type_get() , gnutls_certificate_get_peers() functions
can be used.
The callback function should return 0 for the handshake to continue or non-zero to terminate.
Since: 3.4.6
session: the session for which this will be registered
name: the name of the supplemental data to register
type: the type of the supplemental data format
recv_func: the function to receive the data
send_func: the function to send the data
flags: must be zero
This function will register a new supplemental data type (rfc4680).
The registered supplemental functions will be used for that specific
session. The provided type must be an unassigned type in
gnutls_supplemental_data_format_type_t .
If the type is already registered or handled by GnuTLS internally
GNUTLS_E_ALREADY_REGISTERED will be returned.
As supplemental data are not defined under TLS 1.3, this function will disable TLS 1.3 support for the given session.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.5.5
session: is a gnutls_session_t type.
Request that the client should attempt session resumption using SessionTicket. This call is typically unnecessary as session tickets are enabled by default.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
Since: 2.10.0
session: is a gnutls_session_t type.
key: key to encrypt session parameters.
Request that the server should attempt session resumption using
session tickets, i.e., by delegating storage to the client.
key must be initialized using gnutls_session_ticket_key_generate() .
To avoid leaking that key, use gnutls_memset() prior to
releasing it.
The default ticket expiration time can be overridden using
gnutls_db_set_cache_expiration() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
Since: 2.10.0
key: is a pointer to a gnutls_datum_t which will contain a newly
created key.
Generate a random key to encrypt security parameters within SessionTicket.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
Since: 2.10.0
session: is a gnutls_session_t type.
nr: the number of tickets to send
flags: must be zero
Sends a fresh session ticket to the peer. This is relevant only
in server side under TLS1.3. This function may also return GNUTLS_E_AGAIN
or GNUTLS_E_INTERRUPTED and in that case it must be called again.
Returns: GNUTLS_E_SUCCESS on success, or a negative error code.
session: is a gnutls_session_t type.
Sets the default priority on the ciphers, key exchange methods,
and macs. This is the recommended method of
setting the defaults, in order to promote consistency between applications
using GnuTLS, and to allow GnuTLS using applications to update settings
in par with the library. For client applications which require
maximum compatibility consider calling gnutls_session_enable_compatibility_mode()
after this function.
For an application to specify additional options to priority string
consider using gnutls_set_default_priority_append() .
To allow a user to override the defaults (e.g., when a user interface
or configuration file is available), the functions
gnutls_priority_set_direct() or gnutls_priority_set() can
be used.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since: 2.1.4
session: is a gnutls_session_t type.
add_prio: is a string describing priorities to be appended to default
err_pos: In case of an error this will have the position in the string the error occurred
flags: must be zero
Sets the default priority on the ciphers, key exchange methods,
and macs with the additional options in add_prio . This is the recommended method of
setting the defaults when only few additional options are to be added. This promotes
consistency between applications using GnuTLS, and allows GnuTLS using applications
to update settings in par with the library.
The add_prio string should start as a normal priority string, e.g.,
’-VERS-TLS-ALL:+VERS-TLS1.3:%COMPAT’ or ’%FORCE_ETM’. That is, it must not start
with ’:’.
To allow a user to override the defaults (e.g., when a user interface
or configuration file is available), the functions
gnutls_priority_set_direct() or gnutls_priority_set() can
be used.
Returns: GNUTLS_E_SUCCESS on success, or an error code.
Since: 3.6.3
session: is a gnutls_session_t type.
Returns the signature algorithm that is (or will be) used in this session by the server to sign data. This function should be used only with TLS 1.2 or later.
Returns: The sign algorithm or GNUTLS_SIGN_UNKNOWN .
Since: 3.1.1
session: is a gnutls_session_t type.
Returns the signature algorithm that is (or will be) used in this session by the client to sign data. This function should be used only with TLS 1.2 or later.
Returns: The sign algorithm or GNUTLS_SIGN_UNKNOWN .
Since: 3.1.11
session: is a gnutls_session_t type.
indx: is an index of the signature algorithm to return
algo: the returned certificate type will be stored there
Returns the signature algorithm specified by index that was
requested by the peer. If the specified index has no data available
this function returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE . If
the negotiated TLS version does not support signature algorithms
then GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned even
for the first index. The first index is 0.
This function is useful in the certificate callback functions to assist in selecting the correct certificate.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 2.10.0
sign: is a signature algorithm
This function returns the digest algorithm corresponding to the given signature algorithms.
Since: 3.1.1
Returns: return a gnutls_digest_algorithm_t value, or GNUTLS_DIG_UNKNOWN on error.
name: is a sign algorithm name
The names are compared in a case insensitive way.
Returns: return a gnutls_sign_algorithm_t value corresponding to
the specified algorithm, or GNUTLS_SIGN_UNKNOWN on error.
algorithm: is a sign algorithm
Convert a gnutls_sign_algorithm_t value to a string.
Returns: a string that contains the name of the specified sign
algorithm, or NULL .
sign: is a sign algorithm
Convert a gnutls_sign_algorithm_t value to its object identifier.
Returns: a string that contains the object identifier of the specified sign
algorithm, or NULL .
Since: 3.4.3
sign: is a signature algorithm
This function returns the public key algorithm corresponding to
the given signature algorithms. Note that there may be multiple
public key algorithms supporting a particular signature type;
when dealing with such algorithms use instead gnutls_sign_supports_pk_algorithm() .
Since: 3.1.1
Returns: return a gnutls_pk_algorithm_t value, or GNUTLS_PK_UNKNOWN on error.
algorithm: is a sign algorithm
Returns: Non-zero if the provided signature algorithm is considered to be secure.
algorithm: is a sign algorithm
flags: zero or GNUTLS_SIGN_FLAG_SECURE_FOR_CERTS
Returns: Non-zero if the provided signature algorithm is considered to be secure.
Get a list of supported public key signature algorithms. This function is not thread safe.
Returns: a (0)-terminated list of gnutls_sign_algorithm_t
integers indicating the available ciphers.
sign: the sign algorithm
secure: whether to mark the sign algorithm secure
Modify the previous system wide setting that marked sign as secure
or insecure. Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
This function is not thread-safe and is intended to be called in the main thread at the beginning of the process execution.
Even when secure is true, sign is not marked as secure for the
use in certificates. Use gnutls_sign_set_secure_for_certs() to
mark it secure as well for certificates.
Returns: 0 on success or negative error code otherwise.
Since: 3.7.3
sign: the sign algorithm
secure: whether to mark the sign algorithm secure for certificates
Modify the previous system wide setting that marked sign as secure
or insecure for the use in certificates. Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
This function is not thread-safe and is intended to be called
in the main thread at the beginning of the process execution.
When secure is true, sign is marked as secure for any use unlike
gnutls_sign_set_secure() . Otherwise, it is marked as insecure only
for the use in certificates. Use gnutls_sign_set_secure() to mark
it insecure for any uses.
Returns: 0 on success or negative error code otherwise.
Since: 3.7.3
sign: is a signature algorithm
pk: is a public key algorithm
This function returns non-zero if the public key algorithm corresponds to the given signature algorithm. That is, if that signature can be generated from the given private key algorithm.
Since: 3.6.0
Returns: return non-zero when the provided algorithms are compatible.
sc: is a pointer to a gnutls_srp_server_credentials_t type.
Allocate a gnutls_srp_client_credentials_t structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
sc: is a pointer to a gnutls_srp_server_credentials_t type.
Allocate a gnutls_srp_server_credentials_t structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
b64_data: contain the encoded data
result: the place where decoded data will be copied
result_size: holds the size of the result
This function will decode the given encoded data, using the base64 encoding found in libsrp.
Note that b64_data should be null terminated.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
Returns: GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
long enough, or 0 on success.
b64_data: contains the encoded data
result: the place where decoded data lie
This function will decode the given encoded data. The decoded data will be allocated, and stored into result. It will decode using the base64 algorithm as used in libsrp.
You should use gnutls_free() to free the returned data.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
Returns: 0 on success, or an error code.
data: contain the raw data
result: the place where base64 data will be copied
result_size: holds the size of the result
This function will convert the given data to printable data, using the base64 encoding, as used in the libsrp. This is the encoding used in SRP password files. If the provided buffer is not long enough GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
Returns: GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
long enough, or 0 on success.
data: contains the raw data
result: will hold the newly allocated encoded data
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in SRP password files. This function will allocate the required memory to hold the encoded data.
You should use gnutls_free() to free the returned data.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
Returns: 0 on success, or an error code.
sc: is a gnutls_srp_client_credentials_t type.
Free a gnutls_srp_client_credentials_t structure.
sc: is a gnutls_srp_server_credentials_t type.
Free a gnutls_srp_server_credentials_t structure.
session: is a gnutls session
This function will return the username of the peer. This should only be called in case of SRP authentication and in case of a server. Returns NULL in case of an error.
Returns: SRP username of the peer, or NULL in case of error.
res: is a gnutls_srp_client_credentials_t type.
username: is the user’s userid
password: is the user’s password
This function sets the username and password, in a
gnutls_srp_client_credentials_t type. Those will be used in
SRP authentication. username should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The password can
be in ASCII format, or normalized using gnutls_utf8_password_normalize() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
cred: is a gnutls_srp_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the username and password for client SRP authentication. The callback’s function form is:
int (*callback)(gnutls_session_t, char** username, char**password);
The username and password must be allocated using
gnutls_malloc() .
The username should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The password can
be in ASCII format, or normalized using gnutls_utf8_password_normalize() .
The callback function will be called once per handshake before the initial hello message is sent.
The callback should not return a negative error code the second time called, since the handshake procedure will be aborted.
The callback function should return 0 on success. -1 indicates an error.
session: is a gnutls_session_t type.
bits: is the number of bits
This function sets the minimum accepted number of bits, for use in an SRP key exchange. If zero, the default 2048 bits will be used.
In the client side it sets the minimum accepted number of bits. If
a server sends a prime with less bits than that
GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER will be returned by the
handshake.
This function has no effect in server side.
Since: 2.6.0
res: is a gnutls_srp_server_credentials_t type.
password_file: is the SRP password file (tpasswd)
password_conf_file: is the SRP password conf file (tpasswd.conf)
This function sets the password files, in a
gnutls_srp_server_credentials_t type. Those password files
hold usernames and verifiers and will be used for SRP
authentication.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
cred: is a gnutls_srp_server_credentials_t type.
func: is the callback function
This function can be used to set a callback to retrieve the user’s SRP credentials. The callback’s function form is:
int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t *salt, gnutls_datum_t *verifier, gnutls_datum_t *generator, gnutls_datum_t *prime);
username contains the actual username.
The salt , verifier , generator and prime must be filled
in using the gnutls_malloc() . For convenience prime and generator may also be one of the static parameters defined in gnutls.h.
Initially, the data field is NULL in every gnutls_datum_t
structure that the callback has to fill in. When the
callback is done GnuTLS deallocates all of those buffers
which are non-NULL, regardless of the return value.
In order to prevent attackers from guessing valid usernames,
if a user does not exist, g and n values should be filled in
using a random user’s parameters. In that case the callback must
return the special value (1).
See gnutls_srp_set_server_fake_salt_seed too.
If this is not required for your application, return a negative
number from the callback to abort the handshake.
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
cred: is a gnutls_srp_server_credentials_t type
seed: is the seed data, only needs to be valid until the function returns; size of the seed must be greater than zero
salt_length: is the length of the generated fake salts
This function sets the seed that is used to generate salts for invalid (non-existent) usernames.
In order to prevent attackers from guessing valid usernames, when a user does not exist gnutls generates a salt and a verifier and proceeds with the protocol as usual. The authentication will ultimately fail, but the client cannot tell whether the username is valid (exists) or invalid.
If an attacker learns the seed, given a salt (which is part of the handshake) which was generated when the seed was in use, it can tell whether or not the authentication failed because of an unknown username. This seed cannot be used to reveal application data or passwords.
salt_length should represent the salt length your application uses.
Generating fake salts longer than 20 bytes is not supported.
By default the seed is a random value, different each time a
gnutls_srp_server_credentials_t is allocated and fake salts are
16 bytes long.
Since: 3.3.0
username: is the user’s name
password: is the user’s password
salt: should be some randomly generated bytes
generator: is the generator of the group
prime: is the group’s prime
res: where the verifier will be stored.
This function will create an SRP verifier, as specified in
RFC2945. The prime and generator should be one of the static
parameters defined in gnutls/gnutls.h or may be generated.
The verifier will be allocated with gnutls_malloc () and will be stored in
res using binary format.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, or an
error code.
session: is a gnutls_session_t type.
key_material: Space to hold the generated key material
key_material_size: The maximum size of the key material
client_key: The master client write key, pointing inside the key material
client_salt: The master client write salt, pointing inside the key material
server_key: The master server write key, pointing inside the key material
server_salt: The master server write salt, pointing inside the key material
This is a helper function to generate the keying material for SRTP.
It requires the space of the key material to be pre-allocated (should be at least
2x the maximum key size and salt size). The client_key , client_salt , server_key and server_salt are convenience datums that point inside the key material. They may
be NULL .
Returns: On success the size of the key material is returned,
otherwise, GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
sufficient, or a negative error code.
Since 3.1.4
session: is a gnutls_session_t type.
mki: will hold the MKI
This function exports the negotiated Master Key Identifier,
received by the peer if any. The returned value in mki should be
treated as constant and valid only during the session’s lifetime.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.1.4
name: The name of the profile to look up
profile: Will hold the profile id
This function allows you to look up a profile based on a string.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.1.4
profile: The profile to look up a string for
This function allows you to get the corresponding name for a SRTP protection profile.
Returns: On success, the name of a SRTP profile as a string, otherwise NULL.
Since 3.1.4
session: is a gnutls_session_t type.
profile: will hold the profile
This function allows you to get the negotiated SRTP profile.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.1.4
session: is a gnutls_session_t type.
mki: holds the MKI
This function sets the Master Key Identifier, to be used by this session (if any).
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.1.4
session: is a gnutls_session_t type.
profile: is the profile id to add.
This function is to be used by both clients and servers, to declare what SRTP profiles they support, to negotiate with the peer.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned,
otherwise a negative error code is returned.
Since 3.1.4
session: is a gnutls_session_t type.
profiles: is a string that contains the supported SRTP profiles, separated by colons.
err_pos: In case of an error this will have the position in the string the error occurred, may be NULL.
This function is to be used by both clients and servers, to declare what SRTP profiles they support, to negotiate with the peer.
Returns: On syntax error GNUTLS_E_INVALID_REQUEST is returned,
GNUTLS_E_SUCCESS on success, or an error code.
Since 3.1.4
db_name: A file specifying the stored keys (use NULL for the default)
tdb: A storage structure or NULL to use the default
host: The peer’s name
service: non-NULL if this key is specific to a service (e.g. http)
hash_algo: The hash algorithm type
hash: The raw hash
expiration: The expiration time (use 0 to disable expiration)
flags: should be 0 or GNUTLS_SCOMMIT_FLAG_ALLOW_BROKEN .
This function will store the provided hash commitment to the list of stored public keys. The key with the given hash will be considered valid until the provided expiration time.
The tdb variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
Note that this function is not thread safe with the default backend.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.0
db_name: A file specifying the stored keys (use NULL for the default)
tdb: A storage structure or NULL to use the default
host: The peer’s name
service: non-NULL if this key is specific to a service (e.g. http)
cert_type: The type of the certificate
cert: The data of the certificate
expiration: The expiration time (use 0 to disable expiration)
flags: should be 0.
This function will store a raw public-key or a public-key provided via a raw (DER-encoded) certificate to the list of stored public keys. The key will be considered valid until the provided expiration time.
The tdb variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
Unless an alternative tdb is provided, the storage format is a textual format
consisting of a line for each host with fields separated by ’|’. The contents of
the fields are a format-identifier which is set to ’g0’, the hostname that the
rest of the data applies to, the numeric port or host name, the expiration
time in seconds since the epoch (0 for no expiration), and a base64
encoding of the raw (DER) public key information (SPKI) of the peer.
As of GnuTLS 3.6.6 this function also accepts raw public keys.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
Since: 3.0.13
error: is a GnuTLS error code, a negative error code
This function is similar to strerror. The difference is that it
accepts an error number returned by a gnutls function; In case of
an unknown error a descriptive string is sent instead of NULL .
Error codes are always a negative error code.
Returns: A string explaining the GnuTLS error message.
error: is an error returned by a gnutls function.
Return the GnuTLS error code define as a string. For example, gnutls_strerror_name (GNUTLS_E_DH_PRIME_UNACCEPTABLE) will return the string "GNUTLS_E_DH_PRIME_UNACCEPTABLE".
Returns: A string corresponding to the symbol name of the error code.
Since: 2.6.0
type: is a supplemental data format type
Convert a gnutls_supplemental_data_format_type_t value to a
string.
Returns: a string that contains the name of the specified
supplemental data format type, or NULL for unknown types.
session: is a gnutls_session_t type.
do_recv_supplemental: non-zero in order to expect supplemental data
This function is to be called by an extension handler to instruct gnutls to attempt to receive supplemental data during the handshake process.
Since: 3.4.0
name: the name of the supplemental data to register
type: the type of the supplemental data format
recv_func: the function to receive the data
send_func: the function to send the data
This function will register a new supplemental data type (rfc4680).
The registered data will remain until gnutls_global_deinit()
is called. The provided type must be an unassigned type in
gnutls_supplemental_data_format_type_t . If the type is already
registered or handled by GnuTLS internally GNUTLS_E_ALREADY_REGISTERED
will be returned.
This function is not thread safe. As supplemental data are not defined under TLS 1.3, this function will disable TLS 1.3 support globally.
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
session: is a gnutls_session_t type.
do_send_supplemental: non-zero in order to send supplemental data
This function is to be called by an extension handler to instruct gnutls to send supplemental data during the handshake process.
Since: 3.4.0
ptr: A file descriptor (wrapped in a gnutls_transport_ptr_t pointer)
ms: The number of milliseconds to wait.
Wait for data to be received from the provided socket ( ptr ) within a
timeout period in milliseconds, using select() on the provided ptr .
This function is provided as a helper for constructing custom
callbacks for gnutls_transport_set_pull_timeout_function() ,
which can be used if you rely on socket file descriptors.
Returns -1 on error, 0 on timeout, positive value if data are available for reading.
Since: 3.4.0
tdb: The structure to be deinitialized
This function will deinitialize a public key trust storage structure.
tdb: A pointer to the type to be initialized
This function will initialize a public key trust storage structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a
negative error value.
tdb: The trust storage
cstore: The commitment storage function
This function will associate a commitment (hash) storage function with the trust storage structure. The function is of the following form.
int gnutls_tdb_store_commitment_func(const char* db_name, const char* host, const char* service, time_t expiration, gnutls_digest_algorithm_t, const gnutls_datum_t* hash);
The db_name should be used to pass any private data to this function.
tdb: The trust storage
store: The storage function
This function will associate a storage function with the trust storage structure. The function is of the following form.
int gnutls_tdb_store_func(const char* db_name, const char* host, const char* service, time_t expiration, const gnutls_datum_t* pubkey);
The db_name should be used to pass any private data to this function.
tdb: The trust storage
verify: The verification function
This function will associate a retrieval function with the trust storage structure. The function is of the following form.
int gnutls_tdb_verify_func(const char* db_name, const char* host, const char* service, const gnutls_datum_t* pubkey);
The verify function should return zero on a match, GNUTLS_E_CERTIFICATE_KEY_MISMATCH
if there is a mismatch and any other negative error code otherwise.
The db_name should be used to pass any private data to this function.
session: is a gnutls_session_t type.
Used to get the first argument of the transport function (like
PUSH and PULL). This must have been set using
gnutls_transport_set_int() .
Returns: The first argument of the transport function.
Since: 3.1.9
session: is a gnutls_session_t type.
recv_int: will hold the value for the pull function
send_int: will hold the value for the push function
Used to get the arguments of the transport functions (like PUSH
and PULL). These should have been set using
gnutls_transport_set_int2() .
Since: 3.1.9
session: is a gnutls_session_t type.
Used to get the first argument of the transport function (like
PUSH and PULL). This must have been set using
gnutls_transport_set_ptr() .
Returns: The first argument of the transport function.
session: is a gnutls_session_t type.
recv_ptr: will hold the value for the pull function
send_ptr: will hold the value for the push function
Used to get the arguments of the transport functions (like PUSH
and PULL). These should have been set using
gnutls_transport_set_ptr2() .
session: is a gnutls_session_t type.
Checks if KTLS is now enabled and was properly inicialized.
Returns: GNUTLS_KTLS_RECV , GNUTLS_KTLS_SEND , GNUTLS_KTLS_DUPLEX , otherwise 0
Since: 3.7.3
session: is a gnutls_session_t type.
err: error value to store in session-specific errno variable.
Store err in the session-specific errno variable. Useful values
for err are EINTR, EAGAIN and EMSGSIZE, other values are treated will be
treated as real errors in the push/pull function.
This function is useful in replacement push and pull functions set by
gnutls_transport_set_push_function() and
gnutls_transport_set_pull_function() under Windows, where the
replacements may not have access to the same errno variable that is used by GnuTLS (e.g., the application is linked to
msvcr71.dll and gnutls is linked to msvcrt.dll).
This function is unreliable if you are using the same
session in different threads for sending and receiving.
session: is a gnutls_session_t type.
errno_func: a callback function similar to write()
This is the function where you set a function to retrieve errno after a failed push or pull operation.
errno_func is of the form,
int (*gnutls_errno_func)(gnutls_transport_ptr_t);
and should return the errno.
Since: 2.12.0
session: is a gnutls_session_t type.
fd: is the socket descriptor for the connection.
This function sets the first argument of the transport function, such
as send() and recv() for the default callbacks using the
system’s socket API.
This function is equivalent to calling gnutls_transport_set_ptr()
with the descriptor, but requires no casts.
Since: 3.1.9
session: is a gnutls_session_t type.
recv_fd: is socket descriptor for the pull function
send_fd: is socket descriptor for the push function
This function sets the first argument of the transport functions,
such as send() and recv() for the default callbacks using the
system’s socket API. With this function you can set two different
descriptors for receiving and sending.
This function is equivalent to calling gnutls_transport_set_ptr2()
with the descriptors, but requires no casts.
Since: 3.1.9
session: is a gnutls_session_t type.
ptr: is the value.
Used to set the first argument of the transport function (for push and pull callbacks). In berkeley style sockets this function will set the connection descriptor.
session: is a gnutls_session_t type.
recv_ptr: is the value for the pull function
send_ptr: is the value for the push function
Used to set the first argument of the transport function (for push and pull callbacks). In berkeley style sockets this function will set the connection descriptor. With this function you can use two different pointers for receiving and sending.
session: is a gnutls_session_t type.
pull_func: a callback function similar to read()
This is the function where you set a function for gnutls to receive data. Normally, if you use berkeley style sockets, do not need to use this function since the default recv(2) will probably be ok. The callback should return 0 on connection termination, a positive number indicating the number of bytes received, and -1 on error.
gnutls_pull_func is of the form,
ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
session: is a gnutls_session_t type.
func: a callback function
This is the function where you set a function for gnutls to know
whether data are ready to be received. It should wait for data a
given time frame in milliseconds. The callback should return 0 on
timeout, a positive number if data can be received, and -1 on error.
You’ll need to override this function if select() is not suitable
for the provided transport calls.
As with select() , if the timeout value is zero the callback should return
zero if no data are immediately available. The special value
GNUTLS_INDEFINITE_TIMEOUT indicates that the callback should wait indefinitely
for data.
gnutls_pull_timeout_func is of the form,
int (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);
This callback is necessary when gnutls_handshake_set_timeout() or
gnutls_record_set_timeout() are set, under TLS1.3 and for enforcing the DTLS
mode timeouts when in blocking mode.
For compatibility with future GnuTLS versions this callback must be set when
a custom pull function is registered. The callback will not be used when the
session is in TLS mode with non-blocking sockets. That is, when GNUTLS_NONBLOCK
is specified for a TLS session in gnutls_init() .
The helper function gnutls_system_recv_timeout() is provided to
simplify writing callbacks.
Since: 3.0
session: is a gnutls_session_t type.
push_func: a callback function similar to write()
This is the function where you set a push function for gnutls to use in order to send data. If you are going to use berkeley style sockets, you do not need to use this function since the default send(2) will probably be ok. Otherwise you should specify this function for gnutls to be able to send data. The callback should return a positive number indicating the bytes sent, and -1 on error.
push_func is of the form,
ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
session: is a gnutls_session_t type.
vec_func: a callback function similar to writev()
Using this function you can override the default writev(2)
function for gnutls to send data. Setting this callback
instead of gnutls_transport_set_push_function() is recommended
since it introduces less overhead in the TLS handshake process.
vec_func is of the form,
ssize_t (*gnutls_vec_push_func) (gnutls_transport_ptr_t, const giovec_t * iov, int iovcnt);
Since: 2.12.0
url: A URI to be tested
Check whether the provided url is supported. Depending on the system libraries
GnuTLS may support pkcs11, tpmkey or other URLs.
Returns: return non-zero if the given URL is supported, and zero if it is not known.
Since: 3.1.0
password: contain the UTF-8 formatted password
plen: the length of the provided password
out: the result in an null-terminated allocated string
flags: should be zero
This function will convert the provided UTF-8 password according to the normalization rules in RFC7613.
If the flag GNUTLS_UTF8_IGNORE_ERRS is specified, any UTF-8 encoding
errors will be ignored, and in that case the output will be a copy of the input.
Returns: GNUTLS_E_INVALID_UTF8_STRING on invalid UTF-8 data, or 0 on success.
Since: 3.5.7
db_name: A file specifying the stored keys (use NULL for the default)
tdb: A storage structure or NULL to use the default
host: The peer’s name
service: non-NULL if this key is specific to a service (e.g. http)
cert_type: The type of the certificate
cert: The raw (der) data of the certificate
flags: should be 0.
This function will try to verify a raw public-key or a public-key provided via
a raw (DER-encoded) certificate using a list of stored public keys.
The service field if non-NULL should be a port number.
The db_name variable if non-null specifies a custom backend for
the retrieval of entries. If it is NULL then the
default file backend will be used. In POSIX-like systems the
file backend uses the $HOME/.gnutls/known_hosts file.
Note that if the custom storage backend is provided the
retrieval function should return GNUTLS_E_CERTIFICATE_KEY_MISMATCH
if the host/service pair is found but key doesn’t match,
GNUTLS_E_NO_CERTIFICATE_FOUND if no such host/service with
the given key is found, and 0 if it was found. The storage
function should return 0 on success.
As of GnuTLS 3.6.6 this function also verifies raw public keys.
Returns: If no associated public key is found
then GNUTLS_E_NO_CERTIFICATE_FOUND will be returned. If a key
is found but does not match GNUTLS_E_CERTIFICATE_KEY_MISMATCH
is returned. On success, GNUTLS_E_SUCCESS (0) is returned,
or a negative error value on other errors.
Since: 3.0.13
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