/*
* Copyright (C) 2003-2012 Free Software Foundation, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see
*
*/
/* All functions which relate to X.509 certificate verification stuff are
* included here
*/
#include
#include
#include
#include
#include /* MAX */
#include
#include
#include
#include
#include
#include
/* Checks if two certs are identical. Return 1 on match. */
int
_gnutls_check_if_same_cert(gnutls_x509_crt_t cert1,
gnutls_x509_crt_t cert2)
{
gnutls_datum_t cert1bin = { NULL, 0 }, cert2bin = {
NULL, 0};
int result;
result = _gnutls_is_same_dn(cert1, cert2);
if (result == 0)
return 0;
result = _gnutls_x509_der_encode(cert1->cert, "", &cert1bin, 0);
if (result < 0) {
result = 0;
gnutls_assert();
goto cleanup;
}
result = _gnutls_x509_der_encode(cert2->cert, "", &cert2bin, 0);
if (result < 0) {
result = 0;
gnutls_assert();
goto cleanup;
}
if ((cert1bin.size == cert2bin.size) &&
(memcmp(cert1bin.data, cert2bin.data, cert1bin.size) == 0))
result = 1;
else
result = 0;
cleanup:
_gnutls_free_datum(&cert1bin);
_gnutls_free_datum(&cert2bin);
return result;
}
/* Checks if the issuer of a certificate is a
* Certificate Authority, or if the certificate is the same
* as the issuer (and therefore it doesn't need to be a CA).
*
* Returns true or false, if the issuer is a CA,
* or not.
*/
static int
check_if_ca(gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer,
unsigned int *max_path, unsigned int flags)
{
gnutls_datum_t cert_signed_data = { NULL, 0 };
gnutls_datum_t issuer_signed_data = { NULL, 0 };
gnutls_datum_t cert_signature = { NULL, 0 };
gnutls_datum_t issuer_signature = { NULL, 0 };
int pathlen, result;
unsigned int ca_status;
/* Check if the issuer is the same with the
* certificate. This is added in order for trusted
* certificates to be able to verify themselves.
*/
result =
_gnutls_x509_get_signed_data(issuer->cert, "tbsCertificate",
&issuer_signed_data);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signed_data(cert->cert, "tbsCertificate",
&cert_signed_data);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature(issuer->cert, "signature",
&issuer_signature);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature(cert->cert, "signature",
&cert_signature);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
/* If the subject certificate is the same as the issuer
* return true.
*/
if (!(flags & GNUTLS_VERIFY_DO_NOT_ALLOW_SAME))
if (cert_signed_data.size == issuer_signed_data.size) {
if ((memcmp
(cert_signed_data.data,
issuer_signed_data.data,
cert_signed_data.size) == 0)
&& (cert_signature.size ==
issuer_signature.size)
&&
(memcmp
(cert_signature.data, issuer_signature.data,
cert_signature.size) == 0)) {
result = 1;
goto cleanup;
}
}
result =
gnutls_x509_crt_get_basic_constraints(issuer, NULL, &ca_status,
&pathlen);
if (result < 0) {
ca_status = 0;
pathlen = -1;
}
if (ca_status != 0 && pathlen != -1) {
if ((unsigned) pathlen < *max_path)
*max_path = pathlen;
}
if (ca_status != 0) {
result = 1;
goto cleanup;
}
/* Handle V1 CAs that do not have a basicConstraint, but accept
these certs only if the appropriate flags are set. */
else if ((result == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) &&
((flags & GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT) ||
(!(flags & GNUTLS_VERIFY_DO_NOT_ALLOW_X509_V1_CA_CRT) &&
(gnutls_x509_crt_check_issuer(issuer, issuer) != 0)))) {
gnutls_assert();
result = 1;
goto cleanup;
} else
gnutls_assert();
result = 0;
cleanup:
_gnutls_free_datum(&cert_signed_data);
_gnutls_free_datum(&issuer_signed_data);
_gnutls_free_datum(&cert_signature);
_gnutls_free_datum(&issuer_signature);
return result;
}
/* This function checks if cert's issuer is issuer.
* This does a straight (DER) compare of the issuer/subject DN fields in
* the given certificates, as well as check the authority key ID.
*
* Returns 1 if they match and (0) if they don't match.
*/
static int is_issuer(gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer)
{
uint8_t id1[512];
uint8_t id2[512];
size_t id1_size;
size_t id2_size;
int ret;
if (_gnutls_x509_compare_raw_dn
(&cert->raw_issuer_dn, &issuer->raw_dn) != 0)
ret = 1;
else
ret = 0;
if (ret != 0) {
/* check if the authority key identifier matches the subject key identifier
* of the issuer */
id1_size = sizeof(id1);
ret =
gnutls_x509_crt_get_authority_key_id(cert, id1,
&id1_size, NULL);
if (ret < 0) {
ret = 1;
goto cleanup;
}
id2_size = sizeof(id2);
ret =
gnutls_x509_crt_get_subject_key_id(issuer, id2,
&id2_size, NULL);
if (ret < 0) {
ret = 1;
gnutls_assert();
goto cleanup;
}
if (id1_size == id2_size
&& memcmp(id1, id2, id1_size) == 0)
ret = 1;
else
ret = 0;
}
cleanup:
return ret;
}
/* Check if the given certificate is the issuer of the CRL.
* Returns 1 on success and 0 otherwise.
*/
static int is_crl_issuer(gnutls_x509_crl_t crl, gnutls_x509_crt_t issuer)
{
if (_gnutls_x509_compare_raw_dn
(&crl->raw_issuer_dn, &issuer->raw_dn) != 0)
return 1;
else
return 0;
}
/* Checks if the DN of two certificates is the same.
* Returns 1 if they match and (0) if they don't match. Otherwise
* a negative error code is returned to indicate error.
*/
int _gnutls_is_same_dn(gnutls_x509_crt_t cert1, gnutls_x509_crt_t cert2)
{
if (_gnutls_x509_compare_raw_dn(&cert1->raw_dn, &cert2->raw_dn) !=
0)
return 1;
else
return 0;
}
/* Finds an issuer of the certificate. If multiple issuers
* are present, returns one that is activated and not expired.
*/
static inline gnutls_x509_crt_t
find_issuer(gnutls_x509_crt_t cert,
const gnutls_x509_crt_t * trusted_cas, int tcas_size)
{
int i;
gnutls_x509_crt_t issuer = NULL;
/* this is serial search.
*/
for (i = 0; i < tcas_size; i++) {
if (is_issuer(cert, trusted_cas[i]) != 0) {
if (issuer == NULL) {
issuer = trusted_cas[i];
} else {
time_t now = gnutls_time(0);
if (now <
gnutls_x509_crt_get_expiration_time
(trusted_cas[i])
&& now >=
gnutls_x509_crt_get_activation_time
(trusted_cas[i])) {
issuer = trusted_cas[i];
}
}
}
}
return issuer;
}
static unsigned int check_time(gnutls_x509_crt_t crt, time_t now)
{
int status = 0;
time_t t;
t = gnutls_x509_crt_get_activation_time(crt);
if (t == (time_t) - 1 || now < t) {
status |= GNUTLS_CERT_NOT_ACTIVATED;
status |= GNUTLS_CERT_INVALID;
return status;
}
t = gnutls_x509_crt_get_expiration_time(crt);
if (t == (time_t) - 1 || now > t) {
status |= GNUTLS_CERT_EXPIRED;
status |= GNUTLS_CERT_INVALID;
return status;
}
return 0;
}
static
int is_broken_allowed(gnutls_sign_algorithm_t sig, unsigned int flags)
{
if ((sig == GNUTLS_SIGN_RSA_MD2)
&& (flags & GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2))
return 1;
if ((sig == GNUTLS_SIGN_RSA_MD5)
&& (flags & GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5))
return 1;
return 0;
}
/*
* Verifies the given certificate again a certificate list of
* trusted CAs.
*
* Returns only 0 or 1. If 1 it means that the certificate
* was successfuly verified.
*
* 'flags': an OR of the gnutls_certificate_verify_flags enumeration.
*
* Output will hold some extra information about the verification
* procedure. Issuer will hold the actual issuer from the trusted list.
*/
static int
_gnutls_verify_certificate2(gnutls_x509_crt_t cert,
const gnutls_x509_crt_t * trusted_cas,
int tcas_size, unsigned int flags,
unsigned int *output,
gnutls_x509_crt_t * _issuer,
time_t now,
unsigned int *max_path,
gnutls_verify_output_function func)
{
gnutls_datum_t cert_signed_data = { NULL, 0 };
gnutls_datum_t cert_signature = { NULL, 0 };
gnutls_x509_crt_t issuer = NULL;
int issuer_version, result, hash_algo;
unsigned int out = 0, usage;
if (output)
*output = 0;
if (*max_path == 0) {
out =
GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE |
GNUTLS_CERT_INVALID;
if (output)
*output |= out;
gnutls_assert();
result = 0;
goto cleanup;
}
(*max_path)--;
if (tcas_size >= 1)
issuer = find_issuer(cert, trusted_cas, tcas_size);
/* issuer is not in trusted certificate
* authorities.
*/
if (issuer == NULL) {
out = GNUTLS_CERT_SIGNER_NOT_FOUND | GNUTLS_CERT_INVALID;
if (output)
*output |= out;
gnutls_assert();
result = 0;
goto cleanup;
}
if (_issuer != NULL)
*_issuer = issuer;
issuer_version = gnutls_x509_crt_get_version(issuer);
if (issuer_version < 0) {
gnutls_assert();
return issuer_version;
}
if (!(flags & GNUTLS_VERIFY_DISABLE_CA_SIGN) &&
((flags & GNUTLS_VERIFY_DO_NOT_ALLOW_X509_V1_CA_CRT)
|| issuer_version != 1)) {
if (check_if_ca(cert, issuer, max_path, flags) == 0) {
gnutls_assert();
out =
GNUTLS_CERT_SIGNER_NOT_CA |
GNUTLS_CERT_INVALID;
if (output)
*output |= out;
result = 0;
goto cleanup;
}
result =
gnutls_x509_crt_get_key_usage(issuer, &usage, NULL);
if (result >= 0) {
if (!(usage & GNUTLS_KEY_KEY_CERT_SIGN)) {
gnutls_assert();
out =
GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE
| GNUTLS_CERT_INVALID;
if (output)
*output |= out;
result = 0;
goto cleanup;
}
}
}
result =
_gnutls_x509_get_signed_data(cert->cert, "tbsCertificate",
&cert_signed_data);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature(cert->cert, "signature",
&cert_signature);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature_algorithm(cert->cert,
"signatureAlgorithm.algorithm");
if (result < 0) {
gnutls_assert();
goto cleanup;
}
hash_algo = gnutls_sign_get_hash_algorithm(result);
result =
_gnutls_x509_verify_data(mac_to_entry(hash_algo),
&cert_signed_data, &cert_signature,
issuer);
if (result == GNUTLS_E_PK_SIG_VERIFY_FAILED) {
gnutls_assert();
out |= GNUTLS_CERT_INVALID | GNUTLS_CERT_SIGNATURE_FAILURE;
/* error. ignore it */
if (output)
*output |= out;
result = 0;
} else if (result < 0) {
gnutls_assert();
goto cleanup;
}
/* If the certificate is not self signed check if the algorithms
* used are secure. If the certificate is self signed it doesn't
* really matter.
*/
if (is_issuer(cert, cert) == 0) {
int sigalg;
sigalg = gnutls_x509_crt_get_signature_algorithm(cert);
if (gnutls_sign_is_secure(sigalg) == 0
&& is_broken_allowed(sigalg, flags) == 0) {
out =
GNUTLS_CERT_INSECURE_ALGORITHM |
GNUTLS_CERT_INVALID;
if (output)
*output |= out;
result = 0;
}
}
/* Check activation/expiration times
*/
if (!(flags & GNUTLS_VERIFY_DISABLE_TIME_CHECKS)) {
/* check the time of the issuer first */
if (!(flags & GNUTLS_VERIFY_DISABLE_TRUSTED_TIME_CHECKS)) {
out |= check_time(issuer, now);
if (out != 0) {
result = 0;
if (output)
*output |= out;
}
}
out |= check_time(cert, now);
if (out != 0) {
result = 0;
if (output)
*output |= out;
}
}
cleanup:
if (result >= 0 && func)
func(cert, issuer, NULL, out);
_gnutls_free_datum(&cert_signed_data);
_gnutls_free_datum(&cert_signature);
return result;
}
/**
* gnutls_x509_crt_check_issuer:
* @cert: is the certificate to be checked
* @issuer: is the certificate of a possible issuer
*
* This function will check if the given certificate was issued by the
* given issuer. It checks the DN fields and the authority
* key identifier and subject key identifier fields match.
*
* Returns: It will return true (1) if the given certificate is issued
* by the given issuer, and false (0) if not.
**/
int
gnutls_x509_crt_check_issuer(gnutls_x509_crt_t cert,
gnutls_x509_crt_t issuer)
{
return is_issuer(cert, issuer);
}
/* Verify X.509 certificate chain.
*
* Note that the return value is an OR of GNUTLS_CERT_* elements.
*
* This function verifies a X.509 certificate list. The certificate
* list should lead to a trusted certificate in order to be trusted.
*/
unsigned int
_gnutls_x509_verify_certificate(const gnutls_x509_crt_t * certificate_list,
int clist_size,
const gnutls_x509_crt_t * trusted_cas,
int tcas_size,
unsigned int flags,
gnutls_verify_output_function func)
{
int i = 0, ret;
unsigned int status = 0, output;
time_t now = gnutls_time(0);
gnutls_x509_crt_t issuer = NULL;
unsigned int max_path;
if (clist_size > 1) {
/* Check if the last certificate in the path is self signed.
* In that case ignore it (a certificate is trusted only if it
* leads to a trusted party by us, not the server's).
*
* This prevents from verifying self signed certificates against
* themselves. This (although not bad) caused verification
* failures on some root self signed certificates that use the
* MD2 algorithm.
*/
if (gnutls_x509_crt_check_issuer
(certificate_list[clist_size - 1],
certificate_list[clist_size - 1]) != 0) {
clist_size--;
}
}
/* We want to shorten the chain by removing the cert that matches
* one of the certs we trust and all the certs after that i.e. if
* cert chain is A signed-by B signed-by C signed-by D (signed-by
* self-signed E but already removed above), and we trust B, remove
* B, C and D. */
if (!(flags & GNUTLS_VERIFY_DO_NOT_ALLOW_SAME))
i = 0; /* also replace the first one */
else
i = 1; /* do not replace the first one */
for (; i < clist_size; i++) {
int j;
for (j = 0; j < tcas_size; j++) {
if (_gnutls_check_if_same_cert
(certificate_list[i], trusted_cas[j]) != 0) {
/* explicity time check for trusted CA that we remove from
* list. GNUTLS_VERIFY_DISABLE_TRUSTED_TIME_CHECKS
*/
if (!
(flags &
GNUTLS_VERIFY_DISABLE_TRUSTED_TIME_CHECKS)
&& !(flags & GNUTLS_VERIFY_DISABLE_TIME_CHECKS)) {
status |=
check_time(trusted_cas[j],
now);
if (status != 0) {
if (func)
func(certificate_list[i], trusted_cas[j], NULL, status);
return status;
}
}
if (func)
func(certificate_list[i],
trusted_cas[j], NULL, status);
clist_size = i;
break;
}
}
/* clist_size may have been changed which gets out of loop */
}
if (clist_size == 0) {
/* The certificate is already present in the trusted certificate list.
* Nothing to verify. */
return status;
}
/* Verify the last certificate in the certificate path
* against the trusted CA certificate list.
*
* If no CAs are present returns CERT_INVALID. Thus works
* in self signed etc certificates.
*/
output = 0;
max_path = MAX_VERIFY_DEPTH;
ret = _gnutls_verify_certificate2(certificate_list[clist_size - 1],
trusted_cas, tcas_size, flags,
&output, &issuer, now, &max_path,
func);
if (ret == 0) {
/* if the last certificate in the certificate
* list is invalid, then the certificate is not
* trusted.
*/
gnutls_assert();
status |= output;
status |= GNUTLS_CERT_INVALID;
return status;
}
/* Verify the certificate path (chain)
*/
for (i = clist_size - 1; i > 0; i--) {
output = 0;
if (i - 1 < 0)
break;
/* note that here we disable this V1 CA flag. So that no version 1
* certificates can exist in a supplied chain.
*/
if (!(flags & GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT))
flags &= ~(GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT);
if ((ret =
_gnutls_verify_certificate2(certificate_list[i - 1],
&certificate_list[i], 1,
flags, &output, NULL, now,
&max_path, func)) == 0) {
status |= output;
status |= GNUTLS_CERT_INVALID;
return status;
}
}
return 0;
}
/* This will return the appropriate hash to verify the given signature.
* If signature is NULL it will return an (or the) appropriate hash for
* the given parameters.
*/
int
_gnutls_x509_verify_algorithm(gnutls_digest_algorithm_t * hash,
const gnutls_datum_t * signature,
gnutls_pk_algorithm_t pk,
gnutls_pk_params_st * issuer_params)
{
return _gnutls_pk_hash_algorithm(pk, signature, issuer_params,
hash);
}
/* verifies if the certificate is properly signed.
* returns GNUTLS_E_PK_VERIFY_SIG_FAILED on failure and 1 on success.
*
* 'data' is the signed data
* 'signature' is the signature!
*/
int
_gnutls_x509_verify_data(const mac_entry_st * me,
const gnutls_datum_t * data,
const gnutls_datum_t * signature,
gnutls_x509_crt_t issuer)
{
gnutls_pk_params_st issuer_params;
int ret;
/* Read the MPI parameters from the issuer's certificate.
*/
ret = _gnutls_x509_crt_get_mpis(issuer, &issuer_params);
if (ret < 0) {
gnutls_assert();
return ret;
}
ret =
pubkey_verify_data(gnutls_x509_crt_get_pk_algorithm
(issuer, NULL), me, data, signature,
&issuer_params);
if (ret < 0) {
gnutls_assert();
}
/* release all allocated MPIs
*/
gnutls_pk_params_release(&issuer_params);
return ret;
}
/**
* gnutls_x509_crt_list_verify:
* @cert_list: is the certificate list to be verified
* @cert_list_length: holds the number of certificate in cert_list
* @CA_list: is the CA list which will be used in verification
* @CA_list_length: holds the number of CA certificate in CA_list
* @CRL_list: holds a list of CRLs.
* @CRL_list_length: the length of CRL list.
* @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
* @verify: will hold the certificate verification output.
*
* This function will try to verify the given certificate list and
* return its status. If no flags are specified (0), this function
* will use the basicConstraints (2.5.29.19) PKIX extension. This
* means that only a certificate authority is allowed to sign a
* certificate.
*
* You must also check the peer's name in order to check if the verified
* certificate belongs to the actual peer.
*
* The certificate verification output will be put in @verify and will
* be one or more of the gnutls_certificate_status_t enumerated
* elements bitwise or'd. For a more detailed verification status use
* gnutls_x509_crt_verify() per list element.
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
gnutls_x509_crt_list_verify(const gnutls_x509_crt_t * cert_list,
int cert_list_length,
const gnutls_x509_crt_t * CA_list,
int CA_list_length,
const gnutls_x509_crl_t * CRL_list,
int CRL_list_length, unsigned int flags,
unsigned int *verify)
{
int i, ret;
if (cert_list == NULL || cert_list_length == 0)
return GNUTLS_E_NO_CERTIFICATE_FOUND;
/* Verify certificate
*/
*verify =
_gnutls_x509_verify_certificate(cert_list, cert_list_length,
CA_list, CA_list_length,
flags, NULL);
/* Check for revoked certificates in the chain.
*/
for (i = 0; i < cert_list_length; i++) {
ret = gnutls_x509_crt_check_revocation(cert_list[i],
CRL_list,
CRL_list_length);
if (ret == 1) { /* revoked */
*verify |= GNUTLS_CERT_REVOKED;
*verify |= GNUTLS_CERT_INVALID;
}
}
return 0;
}
/**
* gnutls_x509_crt_verify:
* @cert: is the certificate to be verified
* @CA_list: is one certificate that is considered to be trusted one
* @CA_list_length: holds the number of CA certificate in CA_list
* @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
* @verify: will hold the certificate verification output.
*
* This function will try to verify the given certificate and return
* its status. Note that a verification error does not imply a negative
* return status. In that case the @verify status is set.
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
gnutls_x509_crt_verify(gnutls_x509_crt_t cert,
const gnutls_x509_crt_t * CA_list,
int CA_list_length, unsigned int flags,
unsigned int *verify)
{
/* Verify certificate
*/
*verify =
_gnutls_x509_verify_certificate(&cert, 1,
CA_list, CA_list_length,
flags, NULL);
return 0;
}
/**
* gnutls_x509_crl_check_issuer:
* @crl: is the CRL to be checked
* @issuer: is the certificate of a possible issuer
*
* This function will check if the given CRL was issued by the given
* issuer certificate.
*
* Returns: true (1) if the given CRL was issued by the given issuer,
* and false (0) if not.
**/
int
gnutls_x509_crl_check_issuer(gnutls_x509_crl_t crl,
gnutls_x509_crt_t issuer)
{
return is_crl_issuer(crl, issuer);
}
static inline gnutls_x509_crt_t
find_crl_issuer(gnutls_x509_crl_t crl,
const gnutls_x509_crt_t * trusted_cas, int tcas_size)
{
int i;
/* this is serial search.
*/
for (i = 0; i < tcas_size; i++) {
if (is_crl_issuer(crl, trusted_cas[i]) != 0)
return trusted_cas[i];
}
gnutls_assert();
return NULL;
}
/**
* gnutls_x509_crl_verify:
* @crl: is the crl to be verified
* @trusted_cas: is a certificate list that is considered to be trusted one
* @tcas_size: holds the number of CA certificates in CA_list
* @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
* @verify: will hold the crl verification output.
*
* This function will try to verify the given crl and return its verification status.
* See gnutls_x509_crt_list_verify() for a detailed description of
* return values. Note that since GnuTLS 3.1.4 this function includes
* the time checks.
*
* Note that value in @verify is set only when the return value of this
* function is success (i.e, failure to trust a CRL a certificate does not imply
* a negative return value).
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
gnutls_x509_crl_verify(gnutls_x509_crl_t crl,
const gnutls_x509_crt_t * trusted_cas,
int tcas_size, unsigned int flags,
unsigned int *verify)
{
/* CRL is ignored for now */
gnutls_datum_t crl_signed_data = { NULL, 0 };
gnutls_datum_t crl_signature = { NULL, 0 };
gnutls_x509_crt_t issuer = NULL;
int result, hash_algo;
time_t now = gnutls_time(0);
unsigned int usage;
if (verify)
*verify = 0;
if (tcas_size >= 1)
issuer = find_crl_issuer(crl, trusted_cas, tcas_size);
/* issuer is not in trusted certificate
* authorities.
*/
if (issuer == NULL) {
gnutls_assert();
if (verify)
*verify |=
GNUTLS_CERT_SIGNER_NOT_FOUND |
GNUTLS_CERT_INVALID;
return 0;
}
if (!(flags & GNUTLS_VERIFY_DISABLE_CA_SIGN)) {
if (gnutls_x509_crt_get_ca_status(issuer, NULL) != 1) {
gnutls_assert();
if (verify)
*verify |=
GNUTLS_CERT_SIGNER_NOT_CA |
GNUTLS_CERT_INVALID;
return 0;
}
result =
gnutls_x509_crt_get_key_usage(issuer, &usage, NULL);
if (result >= 0) {
if (!(usage & GNUTLS_KEY_CRL_SIGN)) {
gnutls_assert();
if (verify)
*verify |=
GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE
| GNUTLS_CERT_INVALID;
return 0;
}
}
}
result =
_gnutls_x509_get_signed_data(crl->crl, "tbsCertList",
&crl_signed_data);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature(crl->crl, "signature",
&crl_signature);
if (result < 0) {
gnutls_assert();
goto cleanup;
}
result =
_gnutls_x509_get_signature_algorithm(crl->crl,
"signatureAlgorithm.algorithm");
if (result < 0) {
gnutls_assert();
goto cleanup;
}
hash_algo = gnutls_sign_get_hash_algorithm(result);
result =
_gnutls_x509_verify_data(mac_to_entry(hash_algo),
&crl_signed_data, &crl_signature,
issuer);
if (result == GNUTLS_E_PK_SIG_VERIFY_FAILED) {
gnutls_assert();
/* error. ignore it */
if (verify)
*verify |= GNUTLS_CERT_SIGNATURE_FAILURE;
result = 0;
} else if (result < 0) {
gnutls_assert();
goto cleanup;
}
{
int sigalg;
sigalg = gnutls_x509_crl_get_signature_algorithm(crl);
if (((sigalg == GNUTLS_SIGN_RSA_MD2) &&
!(flags & GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2)) ||
((sigalg == GNUTLS_SIGN_RSA_MD5) &&
!(flags & GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5))) {
if (verify)
*verify |= GNUTLS_CERT_INSECURE_ALGORITHM;
result = 0;
}
}
if (gnutls_x509_crl_get_this_update(crl) > now && verify)
*verify |= GNUTLS_CERT_REVOCATION_DATA_ISSUED_IN_FUTURE;
if (gnutls_x509_crl_get_next_update(crl) < now && verify)
*verify |= GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED;
cleanup:
if (verify)
*verify |= GNUTLS_CERT_INVALID;
_gnutls_free_datum(&crl_signed_data);
_gnutls_free_datum(&crl_signature);
return result;
}