/* 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;
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 (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;
ret = _gnutls_verify_certificate2 (certificate_list[clist_size - 1],
trusted_cas, tcas_size, flags, &output,
&issuer, now, 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, func)) == 0)
{
status |= output;
status |= GNUTLS_CERT_INVALID;
return status;
}
}
return 0;
}
static unsigned int
CVE_2009_1417_gnutls1_4_3__gnutls_x509_verify_certificate (const gnutls_x509_crt_t * certificate_list,
int clist_size,
const gnutls_x509_crt_t * trusted_cas,
int tcas_size,
const gnutls_x509_crl_t * CRLs,
int crls_size, unsigned int flags)
{
int i = 0, ret;
unsigned int status = 0, output;
/* 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.
*/
ret =
_gnutls_verify_certificate2 (certificate_list[clist_size - 1],
trusted_cas, tcas_size, flags, &output);
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;
}
/* Check for revoked certificates in the chain
*/
#ifdef ENABLE_PKI
for (i = 0; i < clist_size; i++)
{
ret = gnutls_x509_crt_check_revocation (certificate_list[i],
CRLs, crls_size);
if (ret == 1)
{ /* revoked */
status |= GNUTLS_CERT_REVOKED;
status |= GNUTLS_CERT_INVALID;
return status;
}
}
#endif
/* 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).
*/
if (gnutls_x509_crt_check_issuer (certificate_list[clist_size - 1],
certificate_list[clist_size - 1]) > 0
&& clist_size > 0)
{
clist_size--;
}
/* Verify the certificate path (chain)
*/
for (i = clist_size - 1; i > 0; i--)
{
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,
NULL)) == 0)
{
status |= GNUTLS_CERT_INVALID;
return status;
}
}
return 0;
}
