E.4 PKCS 7 API

The following functions are to be used for PKCS 7 structures handling. Their prototypes lie in gnutls/pkcs7.h.

gnutls_pkcs7_add_attr

Function: int gnutls_pkcs7_add_attr (gnutls_pkcs7_attrs_t * list, const char * oid, gnutls_datum_t * data, unsigned flags)

list: A list of existing attributes or pointer to NULL for the first one

oid: the OID of the attribute to be set

data: the raw (DER-encoded) data of the attribute to be set

flags: zero or GNUTLS_PKCS7_ATTR_ENCODE_OCTET_STRING

This function will set a PKCS 7 attribute in the provided list. If this function fails, the previous list would be deallocated.

Note that any attributes set with this function must either be DER or BER encoded, unless a special flag is present.

Returns: On success, the new list head, otherwise NULL .

Since: 3.4.2

gnutls_pkcs7_attrs_deinit

Function: void gnutls_pkcs7_attrs_deinit (gnutls_pkcs7_attrs_t list)

list: A list of existing attributes

This function will clear a PKCS 7 attribute list.

Since: 3.4.2

gnutls_pkcs7_deinit

Function: void gnutls_pkcs7_deinit (gnutls_pkcs7_t pkcs7)

pkcs7: the type to be deinitialized

This function will deinitialize a PKCS7 type.

gnutls_pkcs7_delete_crl

Function: int gnutls_pkcs7_delete_crl (gnutls_pkcs7_t pkcs7, int indx)

pkcs7: The pkcs7 type

indx: the index of the crl to delete

This function will delete a crl from a PKCS7 or RFC2630 crl set. Index starts from 0. Returns 0 on success.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_delete_crt

Function: int gnutls_pkcs7_delete_crt (gnutls_pkcs7_t pkcs7, int indx)

pkcs7: The pkcs7 type

indx: the index of the certificate to delete

This function will delete a certificate from a PKCS7 or RFC2630 certificate set. Index starts from 0. Returns 0 on success.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_export

Function: int gnutls_pkcs7_export (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

pkcs7: The pkcs7 type

format: the format of output params. One of PEM or DER.

output_data: will contain a structure PEM or DER encoded

output_data_size: holds the size of output_data (and will be replaced by the actual size of parameters)

This function will export the pkcs7 structure to DER or PEM format.

If the buffer provided is not long enough to hold the output, then * output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.

If the structure is PEM encoded, it will have a header of "BEGIN PKCS7".

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_export2

Function: int gnutls_pkcs7_export2 (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_fmt_t format, gnutls_datum_t * out)

pkcs7: The pkcs7 type

format: the format of output params. One of PEM or DER.

out: will contain a structure PEM or DER encoded

This function will export the pkcs7 structure to DER or PEM format.

The output buffer is allocated using gnutls_malloc() .

If the structure is PEM encoded, it will have a header of "BEGIN PKCS7".

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

Since: 3.1.3

gnutls_pkcs7_get_attr

Function: int gnutls_pkcs7_get_attr (gnutls_pkcs7_attrs_t list, unsigned idx, char ** oid, gnutls_datum_t * data, unsigned flags)

list: A list of existing attributes or NULL for the first one

idx: the index of the attribute to get

oid: the OID of the attribute (read-only)

data: the raw data of the attribute

flags: zero or GNUTLS_PKCS7_ATTR_ENCODE_OCTET_STRING

This function will get a PKCS 7 attribute from the provided list. The OID is a constant string, but data will be allocated and must be deinitialized by the caller.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned if there are no data in the current index.

Since: 3.4.2

gnutls_pkcs7_get_crl_count

Function: int gnutls_pkcs7_get_crl_count (gnutls_pkcs7_t pkcs7)

pkcs7: The pkcs7 type

This function will return the number of certificates in the PKCS7 or RFC2630 crl set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_get_crl_raw

Function: int gnutls_pkcs7_get_crl_raw (gnutls_pkcs7_t pkcs7, unsigned indx, void * crl, size_t * crl_size)

pkcs7: The pkcs7 type

indx: contains the index of the crl to extract

crl: the contents of the crl will be copied there (may be null)

crl_size: should hold the size of the crl

This function will return a crl of the PKCS7 or RFC2630 crl set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. If the provided buffer is not long enough, then crl_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned. After the last crl has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

gnutls_pkcs7_get_crl_raw2

Function: int gnutls_pkcs7_get_crl_raw2 (gnutls_pkcs7_t pkcs7, unsigned indx, gnutls_datum_t * crl)

pkcs7: The pkcs7 type

indx: contains the index of the crl to extract

crl: will contain the contents of the CRL in an allocated buffer

This function will return a DER encoded CRL of the PKCS7 or RFC2630 crl set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. After the last crl has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

Since: 3.4.2

gnutls_pkcs7_get_crt_count

Function: int gnutls_pkcs7_get_crt_count (gnutls_pkcs7_t pkcs7)

pkcs7: should contain a gnutls_pkcs7_t type

This function will return the number of certificates in the PKCS7 or RFC2630 certificate set.

Returns: On success, a positive number is returned, otherwise a negative error value.

gnutls_pkcs7_get_crt_raw

Function: int gnutls_pkcs7_get_crt_raw (gnutls_pkcs7_t pkcs7, unsigned indx, void * certificate, size_t * certificate_size)

pkcs7: should contain a gnutls_pkcs7_t type

indx: contains the index of the certificate to extract

certificate: the contents of the certificate will be copied there (may be null)

certificate_size: should hold the size of the certificate

This function will return a certificate of the PKCS7 or RFC2630 certificate set.

After the last certificate has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. If the provided buffer is not long enough, then certificate_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.

gnutls_pkcs7_get_crt_raw2

Function: int gnutls_pkcs7_get_crt_raw2 (gnutls_pkcs7_t pkcs7, unsigned indx, gnutls_datum_t * cert)

pkcs7: should contain a gnutls_pkcs7_t type

indx: contains the index of the certificate to extract

cert: will hold the contents of the certificate; must be deallocated with gnutls_free()

This function will return a certificate of the PKCS7 or RFC2630 certificate set.

After the last certificate has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. If the provided buffer is not long enough, then certificate_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.

Since: 3.4.2

gnutls_pkcs7_get_embedded_data

Function: int gnutls_pkcs7_get_embedded_data (gnutls_pkcs7_t pkcs7, unsigned flags, gnutls_datum_t * data)

pkcs7: should contain a gnutls_pkcs7_t type

flags: must be zero or GNUTLS_PKCS7_EDATA_GET_RAW

data: will hold the embedded data in the provided structure

This function will return the data embedded in the signature of the PKCS7 structure. If no data are available then GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

The returned data must be de-allocated using gnutls_free() .

Note, that this function returns the exact same data that are authenticated. If the GNUTLS_PKCS7_EDATA_GET_RAW flag is provided, the returned data will be including the wrapping tag/value as they are encoded in the structure.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

Since: 3.4.8

gnutls_pkcs7_get_embedded_data_oid

Function: const char * gnutls_pkcs7_get_embedded_data_oid (gnutls_pkcs7_t pkcs7)

pkcs7: should contain a gnutls_pkcs7_t type

This function will return the OID of the data embedded in the signature of the PKCS7 structure. If no data are available then NULL will be returned. The returned value will be valid during the lifetime of the pkcs7 structure.

Returns: On success, a pointer to an OID string, NULL on error.

Since: 3.5.5

gnutls_pkcs7_get_signature_count

Function: int gnutls_pkcs7_get_signature_count (gnutls_pkcs7_t pkcs7)

pkcs7: should contain a gnutls_pkcs7_t type

This function will return the number of signatures in the PKCS7 structure.

Returns: On success, a positive number is returned, otherwise a negative error value.

Since: 3.4.3

gnutls_pkcs7_get_signature_info

Function: int gnutls_pkcs7_get_signature_info (gnutls_pkcs7_t pkcs7, unsigned idx, gnutls_pkcs7_signature_info_st * info)

pkcs7: should contain a gnutls_pkcs7_t type

idx: the index of the signature info to check

info: will contain the output signature

This function will return information about the signature identified by idx in the provided PKCS 7 structure. The information should be deinitialized using gnutls_pkcs7_signature_info_deinit() .

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

Since: 3.4.2

gnutls_pkcs7_import

Function: int gnutls_pkcs7_import (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

pkcs7: The data to store the parsed PKCS7.

data: The DER or PEM encoded PKCS7.

format: One of DER or PEM

This function will convert the given DER or PEM encoded PKCS7 to the native gnutls_pkcs7_t format. The output will be stored in pkcs7 . Any signed data that may be present inside the pkcs7 structure, like certificates set by gnutls_pkcs7_set_crt() , will be freed and overwritten by this function.

If the PKCS7 is PEM encoded it should have a header of "PKCS7".

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_init

Function: int gnutls_pkcs7_init (gnutls_pkcs7_t * pkcs7)

pkcs7: A pointer to the type to be initialized

This function will initialize a PKCS7 structure. PKCS7 structures usually contain lists of X.509 Certificates and X.509 Certificate revocation lists.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_print

Function: int gnutls_pkcs7_print (gnutls_pkcs7_t pkcs7, gnutls_certificate_print_formats_t format, gnutls_datum_t * out)

pkcs7: The PKCS7 struct to be printed

format: Indicate the format to use

out: Newly allocated datum with null terminated string.

This function will pretty print a signed PKCS 7 structure, suitable for display to a human.

Currently the supported formats are GNUTLS_CRT_PRINT_FULL and GNUTLS_CRT_PRINT_COMPACT .

The output out needs to be deallocated using gnutls_free() .

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_print_signature_info

Function: int gnutls_pkcs7_print_signature_info (gnutls_pkcs7_signature_info_st * info, gnutls_certificate_print_formats_t format, gnutls_datum_t * out)

info: The PKCS7 signature info struct to be printed

format: Indicate the format to use

out: Newly allocated datum with null terminated string.

This function will pretty print a PKCS 7 signature info structure, suitable for display to a human.

Currently the supported formats are GNUTLS_CRT_PRINT_FULL and GNUTLS_CRT_PRINT_COMPACT .

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: 3.6.14

gnutls_pkcs7_set_crl

Function: int gnutls_pkcs7_set_crl (gnutls_pkcs7_t pkcs7, gnutls_x509_crl_t crl)

pkcs7: The pkcs7 type

crl: the DER encoded crl to be added

This function will add a parsed CRL to the PKCS7 or RFC2630 crl set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_set_crl_raw

Function: int gnutls_pkcs7_set_crl_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crl)

pkcs7: The pkcs7 type

crl: the DER encoded crl to be added

This function will add a crl to the PKCS7 or RFC2630 crl set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_set_crt

Function: int gnutls_pkcs7_set_crt (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t crt)

pkcs7: The pkcs7 type

crt: the certificate to be copied.

This function will add a parsed certificate to the PKCS7 or RFC2630 certificate set. This is a wrapper function over gnutls_pkcs7_set_crt_raw() .

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_set_crt_raw

Function: int gnutls_pkcs7_set_crt_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crt)

pkcs7: The pkcs7 type

crt: the DER encoded certificate to be added

This function will add a certificate to the PKCS7 or RFC2630 certificate set.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

gnutls_pkcs7_sign

Function: int gnutls_pkcs7_sign (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t signer, gnutls_privkey_t signer_key, const gnutls_datum_t * data, gnutls_pkcs7_attrs_t signed_attrs, gnutls_pkcs7_attrs_t unsigned_attrs, gnutls_digest_algorithm_t dig, unsigned flags)

pkcs7: should contain a gnutls_pkcs7_t type

signer: the certificate to sign the structure

signer_key: the key to sign the structure

data: The data to be signed or NULL if the data are already embedded

signed_attrs: Any additional attributes to be included in the signed ones (or NULL )

unsigned_attrs: Any additional attributes to be included in the unsigned ones (or NULL )

dig: The digest algorithm to use for signing

flags: Should be zero or one of GNUTLS_PKCS7 flags

This function will add a signature in the provided PKCS 7 structure for the provided data. Multiple signatures can be made with different signers.

The available flags are: GNUTLS_PKCS7_EMBED_DATA , GNUTLS_PKCS7_INCLUDE_TIME , GNUTLS_PKCS7_INCLUDE_CERT , and GNUTLS_PKCS7_WRITE_SPKI . They are explained in the gnutls_pkcs7_sign_flags definition.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value.

Since: 3.4.2

gnutls_pkcs7_signature_info_deinit

Function: void gnutls_pkcs7_signature_info_deinit (gnutls_pkcs7_signature_info_st * info)

info: should point to a gnutls_pkcs7_signature_info_st structure

This function will deinitialize any allocated value in the provided gnutls_pkcs7_signature_info_st .

Since: 3.4.2

gnutls_pkcs7_verify

Function: int gnutls_pkcs7_verify (gnutls_pkcs7_t pkcs7, gnutls_x509_trust_list_t tl, gnutls_typed_vdata_st * vdata, unsigned int vdata_size, unsigned idx, const gnutls_datum_t * data, unsigned flags)

pkcs7: should contain a gnutls_pkcs7_t type

tl: A list of trusted certificates

vdata: an array of typed data

vdata_size: the number of data elements

idx: the index of the signature info to check

data: The data to be verified or NULL

flags: Zero or an OR list of gnutls_certificate_verify_flags

This function will verify the provided data against the signature present in the SignedData of the PKCS 7 structure. If the data provided are NULL then the data in the encapsulatedContent field will be used instead.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. A verification error results to a GNUTLS_E_PK_SIG_VERIFY_FAILED and the lack of encapsulated data to verify to a GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE .

Since: 3.4.2

gnutls_pkcs7_verify_direct

Function: int gnutls_pkcs7_verify_direct (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t signer, unsigned idx, const gnutls_datum_t * data, unsigned flags)

pkcs7: should contain a gnutls_pkcs7_t type

signer: the certificate believed to have signed the structure

idx: the index of the signature info to check

data: The data to be verified or NULL

flags: Zero or an OR list of gnutls_certificate_verify_flags

This function will verify the provided data against the signature present in the SignedData of the PKCS 7 structure. If the data provided are NULL then the data in the encapsulatedContent field will be used instead.

Note that, unlike gnutls_pkcs7_verify() this function does not verify the key purpose of the signer. It is expected for the caller to verify the intended purpose of the signer -e.g., via gnutls_x509_crt_get_key_purpose_oid() , or gnutls_x509_crt_check_key_purpose() .

Note also, that since GnuTLS 3.5.6 this function introduces checks in the end certificate ( signer ), including time checks and key usage checks.

Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise a negative error value. A verification error results to a GNUTLS_E_PK_SIG_VERIFY_FAILED and the lack of encapsulated data to verify to a GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE .

Since: 3.4.2