diff options
Diffstat (limited to 'lib/cert.c')
| -rw-r--r-- | lib/cert.c | 54 |
1 files changed, 53 insertions, 1 deletions
diff --git a/lib/cert.c b/lib/cert.c index d93b2f6cba..9e42de1c51 100644 --- a/lib/cert.c +++ b/lib/cert.c @@ -245,6 +245,58 @@ gnutls_certificate_allocate_credentials(gnutls_certificate_credentials_t * return 0; } +/* Returns 0 if it's ok to use the gnutls_kx_algorithm_t with this + * certificate (uses the KeyUsage field). + */ +static int +check_key_usage(const gnutls_pcert_st * cert, + gnutls_kx_algorithm_t alg) +{ + unsigned int key_usage = 0; + int encipher_type; + + if (cert == NULL || alg == GNUTLS_KX_UNKNOWN) { + gnutls_assert(); + return GNUTLS_E_INTERNAL_ERROR; + } + + if (_gnutls_map_kx_get_cred(alg, 1) == GNUTLS_CRD_CERTIFICATE || + _gnutls_map_kx_get_cred(alg, 0) == GNUTLS_CRD_CERTIFICATE) { + + gnutls_pubkey_get_key_usage(cert->pubkey, &key_usage); + + encipher_type = _gnutls_kx_encipher_type(alg); + + if (key_usage != 0 && encipher_type != CIPHER_IGN) { + /* If key_usage has been set in the certificate + */ + + if (encipher_type == CIPHER_ENCRYPT) { + /* If the key exchange method requires an encipher + * type algorithm, and key's usage does not permit + * encipherment, then fail. + */ + if (!(key_usage & GNUTLS_KEY_KEY_ENCIPHERMENT)) { + gnutls_assert(); + return + GNUTLS_E_KEY_USAGE_VIOLATION; + } + } + + if (encipher_type == CIPHER_SIGN) { + /* The same as above, but for sign only keys + */ + if (!(key_usage & GNUTLS_KEY_DIGITAL_SIGNATURE)) { + gnutls_assert(); + return + GNUTLS_E_KEY_USAGE_VIOLATION; + } + } + } + } + return 0; +} + /* returns the KX algorithms that are supported by a * certificate. (Eg a certificate with RSA params, supports @@ -275,7 +327,7 @@ _gnutls_selected_cert_supported_kx(gnutls_session_t session, pk = _gnutls_map_kx_get_pk(kx); if (pk == cert_pk) { /* then check key usage */ - if (_gnutls_check_key_usage(cert, kx) == 0 || + if (check_key_usage(cert, kx) == 0 || unlikely(session->internals.priorities.allow_server_key_usage_violation != 0)) { alg[i] = kx; i++; |