File pkcs7.h

PKCS #7 generic defines and structures https://tools.ietf.org/html/rfc2315.

PKCS #7 Module Error codes

Note: For the time being, this implementation of the PKCS #7 cryptographic message syntax is a partial implementation of RFC 2315. Differences include:

The RFC specifies 6 different content types. The only type currently supported in Mbed TLS is the signed-data content type.
The only supported PKCS #7 Signed Data syntax version is version 1
The RFC specifies support for BER. This implementation is limited to DER only.
The RFC specifies that multiple digest algorithms can be specified in the Signed Data type. Only one digest algorithm is supported in Mbed TLS.
The RFC specifies the Signed Data type can contain multiple X.509 or PKCS #6 extended certificates. In Mbed TLS, this list can only contain 0 or 1 certificates and they must be in X.509 format.
The RFC specifies the Signed Data type can contain certificate-revocation lists (CRLs). This implementation has no support for CRLs so it is assumed to be an empty list.
The RFC allows for SignerInfo structure to optionally contain unauthenticatedAttributes and authenticatedAttributes. In Mbed TLS it is assumed these fields are empty.
The RFC allows for the signed Data type to contain contentInfo. This implementation assumes the type is DATA and the content is empty.

MBEDTLS_ERR_PKCS7_INVALID_FORMAT: The format is invalid, e.g. different type expected.

MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE: Unavailable feature, e.g. anything other than signed data.

MBEDTLS_ERR_PKCS7_INVALID_VERSION: The PKCS #7 version element is invalid or cannot be parsed.

MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO: The PKCS #7 content info is invalid or cannot be parsed.

MBEDTLS_ERR_PKCS7_INVALID_ALG: The algorithm tag or value is invalid or cannot be parsed.

MBEDTLS_ERR_PKCS7_INVALID_CERT: The certificate tag or value is invalid or cannot be parsed.

MBEDTLS_ERR_PKCS7_INVALID_SIGNATURE: Error parsing the signature

MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO: Error parsing the signer’s info

MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA: Input invalid.

MBEDTLS_ERR_PKCS7_ALLOC_FAILED: Allocation of memory failed.

MBEDTLS_ERR_PKCS7_VERIFY_FAIL: Verification Failed

MBEDTLS_ERR_PKCS7_CERT_DATE_INVALID: The PKCS #7 date issued/expired dates are invalid

PKCS #7 Supported Version

MBEDTLS_PKCS7_SUPPORTED_VERSION

enum mbedtls_pkcs7_type

PKCS #7 types

Values:

enumerator MBEDTLS_PKCS7_NONE

enumerator MBEDTLS_PKCS7_DATA

enumerator MBEDTLS_PKCS7_SIGNED_DATA

enumerator MBEDTLS_PKCS7_ENVELOPED_DATA

enumerator MBEDTLS_PKCS7_SIGNED_AND_ENVELOPED_DATA

enumerator MBEDTLS_PKCS7_DIGESTED_DATA

enumerator MBEDTLS_PKCS7_ENCRYPTED_DATA

typedef mbedtls_asn1_buf mbedtls_pkcs7_buf: Type-length-value structure that allows for ASN.1 using DER.

typedef mbedtls_asn1_named_data mbedtls_pkcs7_name: Container for ASN.1 named information objects. It allows for Relative Distinguished Names (e.g. cn=localhost,ou=code,etc.).

typedef mbedtls_asn1_sequence mbedtls_pkcs7_sequence: Container for a sequence of ASN.1 items

typedef struct mbedtls_pkcs7_signer_info mbedtls_pkcs7_signer_info: Structure holding PKCS #7 signer info

typedef struct mbedtls_pkcs7_signed_data mbedtls_pkcs7_signed_data: Structure holding the signed data section

typedef struct mbedtls_pkcs7 mbedtls_pkcs7: Structure holding PKCS #7 structure, only signed data for now

void mbedtls_pkcs7_init(mbedtls_pkcs7 *pkcs7)

Initialize mbedtls_pkcs7 structure.

Parameters: pkcs7 – mbedtls_pkcs7 structure.

int mbedtls_pkcs7_parse_der(mbedtls_pkcs7 *pkcs7, const unsigned char *buf, const size_t buflen)

Parse a single DER formatted PKCS #7 detached signature.

Note

This function makes an internal copy of the PKCS #7 buffer buf. In particular, buf may be destroyed or reused after this call returns.

Note

Signatures with internal data are not supported.

Parameters

pkcs7 – The mbedtls_pkcs7 structure to be filled by the parser.
buf – The buffer holding only the DER encoded PKCS #7 content.
buflen – The size in bytes of buf. The size must be exactly the length of the DER encoded PKCS #7 content.

Returns

The mbedtls_pkcs7_type of buf, if successful.

Returns

A negative error code on failure.

int mbedtls_pkcs7_signed_data_verify(mbedtls_pkcs7 *pkcs7, const mbedtls_x509_crt *cert, const unsigned char *data, size_t datalen)

Verification of PKCS #7 signature against a caller-supplied certificate.

For each signer in the PKCS structure, this function computes a signature over the supplied data, using the supplied certificate and the same digest algorithm as specified by the signer. It then compares this signature against the signer’s signature; verification succeeds if any comparison matches.

This function does not use the certificates held within the PKCS #7 structure itself, and does not check that the certificate is signed by a trusted certification authority.

Note

This function internally calculates the hash on the supplied plain data for signature verification.

Parameters

pkcs7 – mbedtls_pkcs7 structure containing signature.
cert – Certificate containing key to verify signature.
data – Plain data on which signature has to be verified.
datalen – Length of the data.

Returns

0 if the signature verifies, or a negative error code on failure.

int mbedtls_pkcs7_signed_hash_verify(mbedtls_pkcs7 *pkcs7, const mbedtls_x509_crt *cert, const unsigned char *hash, size_t hashlen)

Verification of PKCS #7 signature against a caller-supplied certificate.

For each signer in the PKCS structure, this function validates a signature over the supplied hash, using the supplied certificate and the same digest algorithm as specified by the signer. Verification succeeds if any signature is good.

This function does not use the certificates held within the PKCS #7 structure itself, and does not check that the certificate is signed by a trusted certification authority.

Note

This function is different from mbedtls_pkcs7_signed_data_verify() in that it is directly passed the hash of the data.

Parameters