path: root/lib/x509/verify-high.c

/*
 * Copyright (C) 2011-2012 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 <http://www.gnu.org/licenses/>
 *
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <libtasn1.h>
#include <gnutls_global.h>
#include <gnutls_num.h>		/* MAX */
#include <gnutls_sig.h>
#include <gnutls_str.h>
#include <gnutls_datum.h>
#include <hash-pjw-bare.h>
#include "x509_int.h"
#include <common.h>
#include <gnutls/x509-ext.h>
#include "verify-high.h"

struct named_cert_st {
	gnutls_x509_crt_t cert;
	uint8_t name[MAX_SERVER_NAME_SIZE];
	unsigned int name_size;
};

struct node_st {
	/* The trusted certificates */
	gnutls_x509_crt_t *trusted_cas;
	unsigned int trusted_ca_size;

	struct named_cert_st *named_certs;
	unsigned int named_cert_size;

	/* The trusted CRLs */
	gnutls_x509_crl_t *crls;
	unsigned int crl_size;

};

#define DEFAULT_SIZE 127

/**
 * gnutls_x509_trust_list_init:
 * @list: The structure to be initialized
 * @size: The size of the internal hash table. Use (0) for default size.
 *
 * This function will initialize an X.509 trust list structure.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0.0
 **/
int
gnutls_x509_trust_list_init(gnutls_x509_trust_list_t * list,
			    unsigned int size)
{
	gnutls_x509_trust_list_t tmp;

	FAIL_IF_LIB_ERROR;

	tmp =
	    gnutls_calloc(1, sizeof(struct gnutls_x509_trust_list_st));

	if (!tmp)
		return GNUTLS_E_MEMORY_ERROR;

	if (size == 0)
		size = DEFAULT_SIZE;
	tmp->size = size;

	tmp->node = gnutls_calloc(1, tmp->size * sizeof(tmp->node[0]));
	if (tmp->node == NULL) {
		gnutls_assert();
		gnutls_free(tmp);
		return GNUTLS_E_MEMORY_ERROR;
	}

	*list = tmp;

	return 0;		/* success */
}

/**
 * gnutls_x509_trust_list_deinit:
 * @list: The structure to be deinitialized
 * @all: if non-zero it will deinitialize all the certificates and CRLs contained in the structure.
 *
 * This function will deinitialize a trust list. Note that the
 * @all flag should be typically non-zero unless you have specified
 * your certificates using gnutls_x509_trust_list_add_cas() and you
 * want to prevent them from being deinitialized by this function.
 *
 * Since: 3.0.0
 **/
void
gnutls_x509_trust_list_deinit(gnutls_x509_trust_list_t list,
			      unsigned int all)
{
	unsigned int i, j;

	if (!list)
		return;

	for (j = 0; j < list->blacklisted_size; j++) {
		gnutls_x509_crt_deinit(list->blacklisted[j]);
	}
	gnutls_free(list->blacklisted);

	for (i = 0; i < list->size; i++) {
		if (all) {
			for (j = 0; j < list->node[i].trusted_ca_size; j++) {
				gnutls_x509_crt_deinit(list->node[i].
						       trusted_cas[j]);
			}
		}
		gnutls_free(list->node[i].trusted_cas);


		if (all) {
			for (j = 0; j < list->node[i].crl_size; j++) {
				gnutls_x509_crl_deinit(list->node[i].
						       crls[j]);
			}
		}
		gnutls_free(list->node[i].crls);

		if (all) {
			for (j = 0; j < list->node[i].named_cert_size; j++) {
				gnutls_x509_crt_deinit(list->node[i].
						       named_certs[j].
						       cert);
			}
		}
		gnutls_free(list->node[i].named_certs);
	}

	gnutls_free(list->x509_rdn_sequence.data);
	gnutls_free(list->node);
	gnutls_free(list->pkcs11_token);
	gnutls_free(list);
}

static int
add_new_ca_to_rdn_seq(gnutls_x509_trust_list_t list,
		       gnutls_x509_crt_t ca)
{
	gnutls_datum_t tmp;
	size_t newsize;
	unsigned char *newdata, *p;

	/* Add DN of the last added CAs to the RDN sequence
	 * This will be sent to clients when a certificate
	 * request message is sent.
	 */

	/* FIXME: in case of a client it is not needed
	 * to do that. This would save time and memory.
	 * However we don't have that information available
	 * here.
	 * Further, this function is now much more efficient,
	 * so optimizing that is less important.
	 */
	tmp.data = ca->raw_dn.data;
	tmp.size = ca->raw_dn.size;

	newsize = list->x509_rdn_sequence.size + 2 + tmp.size;
	if (newsize < list->x509_rdn_sequence.size) {
		gnutls_assert();
		return GNUTLS_E_SHORT_MEMORY_BUFFER;
	}

	newdata =
	    gnutls_realloc_fast(list->x509_rdn_sequence.data,
				newsize);
	if (newdata == NULL) {
		gnutls_assert();
		return GNUTLS_E_MEMORY_ERROR;
	}

	p = newdata + list->x509_rdn_sequence.size;
	_gnutls_write_uint16(tmp.size, p);
	if (tmp.data != NULL)
		memcpy(p + 2, tmp.data, tmp.size);

	list->x509_rdn_sequence.size = newsize;
	list->x509_rdn_sequence.data = newdata;

	return 0;
}

/**
 * gnutls_x509_trust_list_add_cas:
 * @list: The structure of the list
 * @clist: A list of CAs
 * @clist_size: The length of the CA list
 * @flags: should be 0 or an or'ed sequence of %GNUTLS_TL options.
 *
 * This function will add the given certificate authorities
 * to the trusted list. The list of CAs must not be deinitialized
 * during this structure's lifetime.
 *
 * If the flag %GNUTLS_TL_NO_DUPLICATES is specified, then
 * the provided @clist entries that are duplicates will not be
 * added to the list and will be deinitialized.
 *
 * Returns: The number of added elements is returned.
 *
 * Since: 3.0.0
 **/
int
gnutls_x509_trust_list_add_cas(gnutls_x509_trust_list_t list,
			       const gnutls_x509_crt_t * clist,
			       unsigned clist_size, unsigned int flags)
{
	unsigned i, j;
	uint32_t hash;
	int ret;
	unsigned exists;

	for (i = 0; i < clist_size; i++) {
		exists = 0;
		hash =
		    hash_pjw_bare(clist[i]->raw_dn.data,
				  clist[i]->raw_dn.size);
		hash %= list->size;

		/* avoid duplicates */
		if (flags & GNUTLS_TL_NO_DUPLICATES) {
			for (j=0;j<list->node[hash].trusted_ca_size;j++) {
				if (_gnutls_check_if_same_cert(list->node[hash].trusted_cas[j], clist[i]) != 0) {
					exists = 1;
					break;
				}
			}

			if (exists != 0) {
				gnutls_x509_crt_deinit(clist[i]);
				continue;
			}
		}

		list->node[hash].trusted_cas =
		    gnutls_realloc_fast(list->node[hash].trusted_cas,
					(list->node[hash].trusted_ca_size +
					 1) *
					sizeof(list->node[hash].
					       trusted_cas[0]));
		if (list->node[hash].trusted_cas == NULL) {
			gnutls_assert();
			return i;
		}

		list->node[hash].trusted_cas[list->node[hash].
					     trusted_ca_size] = clist[i];
		list->node[hash].trusted_ca_size++;

		if (flags & GNUTLS_TL_USE_IN_TLS) {
			ret = add_new_ca_to_rdn_seq(list, clist[i]);
			if (ret < 0) {
				gnutls_assert();
				return i;
			}
		}
	}

	return i;
}

static gnutls_x509_crt_t crt_cpy(gnutls_x509_crt_t src)
{
gnutls_x509_crt_t dst;
int ret;

	ret = gnutls_x509_crt_init(&dst);
	if (ret < 0) {
		gnutls_assert();
		return NULL;
	}

	ret = _gnutls_x509_crt_cpy(dst, src);
	if (ret < 0) {
		gnutls_assert();
		return NULL;
	}

	return dst;
}

/**
 * gnutls_x509_trust_list_remove_cas:
 * @list: The structure of the list
 * @clist: A list of CAs
 * @clist_size: The length of the CA list
 *
 * This function will remove the given certificate authorities
 * from the trusted list.
 *
 * Note that this function can accept certificates and authorities
 * not yet known. In that case they will be kept in a separate
 * black list that will be used during certificate verification.
 * Unlike gnutls_x509_trust_list_add_cas() there is no deinitialization
 * restriction for  certificate list provided in this function.
 *
 * Returns: The number of removed elements is returned.
 *
 * Since: 3.1.10
 **/
int
gnutls_x509_trust_list_remove_cas(gnutls_x509_trust_list_t list,
				  const gnutls_x509_crt_t * clist,
				  int clist_size)
{
	int i, r = 0;
	unsigned j;
	uint32_t hash;

	for (i = 0; i < clist_size; i++) {
		hash =
		    hash_pjw_bare(clist[i]->raw_dn.data,
				  clist[i]->raw_dn.size);
		hash %= list->size;

		for (j = 0; j < list->node[hash].trusted_ca_size; j++) {
			if (_gnutls_check_if_same_cert
			    (clist[i],
			     list->node[hash].trusted_cas[j]) != 0) {

				gnutls_x509_crt_deinit(list->node[hash].
						       trusted_cas[j]);
				list->node[hash].trusted_cas[j] =
				    list->node[hash].trusted_cas[list->
								 node
								 [hash].
								 trusted_ca_size
								 - 1];
				list->node[hash].trusted_ca_size--;
				r++;
				break;
			}
		}

		/* Add the CA (or plain) certificate to the black list as well.
		 * This will prevent a subordinate CA from being valid, and 
		 * ensure that a server certificate will also get rejected.
		 */
		list->blacklisted =
		    gnutls_realloc_fast(list->blacklisted,
				(list->blacklisted_size + 1) *
				sizeof(list->blacklisted[0]));
		if (list->blacklisted == NULL)
			return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

		list->blacklisted[list->blacklisted_size] = crt_cpy(clist[i]);
		if (list->blacklisted[list->blacklisted_size] != NULL)
			list->blacklisted_size++;
	}

	return r;
}

/**
 * gnutls_x509_trust_list_add_named_crt:
 * @list: The structure of the list
 * @cert: A certificate
 * @name: An identifier for the certificate
 * @name_size: The size of the identifier
 * @flags: should be 0.
 *
 * This function will add the given certificate to the trusted
 * list and associate it with a name. The certificate will not be
 * be used for verification with gnutls_x509_trust_list_verify_crt()
 * but only with gnutls_x509_trust_list_verify_named_crt().
 *
 * In principle this function can be used to set individual "server"
 * certificates that are trusted by the user for that specific server
 * but for no other purposes.
 *
 * The certificate must not be deinitialized during the lifetime
 * of the trusted list.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0.0
 **/
int
gnutls_x509_trust_list_add_named_crt(gnutls_x509_trust_list_t list,
				     gnutls_x509_crt_t cert,
				     const void *name, size_t name_size,
				     unsigned int flags)
{
	uint32_t hash;

	if (name_size >= MAX_SERVER_NAME_SIZE)
		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	hash =
	    hash_pjw_bare(cert->raw_issuer_dn.data,
			  cert->raw_issuer_dn.size);
	hash %= list->size;

	list->node[hash].named_certs =
	    gnutls_realloc_fast(list->node[hash].named_certs,
				(list->node[hash].named_cert_size +
				 1) *
				sizeof(list->node[hash].named_certs[0]));
	if (list->node[hash].named_certs == NULL)
		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

	list->node[hash].named_certs[list->node[hash].named_cert_size].
	    cert = cert;
	memcpy(list->node[hash].
	       named_certs[list->node[hash].named_cert_size].name, name,
	       name_size);
	list->node[hash].named_certs[list->node[hash].
				     named_cert_size].name_size =
	    name_size;

	list->node[hash].named_cert_size++;

	return 0;
}

/**
 * gnutls_x509_trust_list_add_crls:
 * @list: The structure of the list
 * @crl_list: A list of CRLs
 * @crl_size: The length of the CRL list
 * @flags: if GNUTLS_TL_VERIFY_CRL is given the CRLs will be verified before being added.
 * @verification_flags: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
 *
 * This function will add the given certificate revocation lists
 * to the trusted list. The list of CRLs must not be deinitialized
 * during this structure's lifetime.
 *
 * This function must be called after gnutls_x509_trust_list_add_cas()
 * to allow verifying the CRLs for validity.
 *
 * Returns: The number of added elements is returned.
 *
 * Since: 3.0
 **/
int
gnutls_x509_trust_list_add_crls(gnutls_x509_trust_list_t list,
				const gnutls_x509_crl_t * crl_list,
				int crl_size, unsigned int flags,
				unsigned int verification_flags)
{
	int ret, i, j = 0;
	unsigned int vret = 0;
	uint32_t hash;

	/* Probably we can optimize things such as removing duplicates
	 * etc.
	 */
	if (crl_size == 0 || crl_list == NULL)
		return 0;

	for (i = 0; i < crl_size; i++) {
		hash =
		    hash_pjw_bare(crl_list[i]->raw_issuer_dn.data,
				  crl_list[i]->raw_issuer_dn.size);
		hash %= list->size;

		if (flags & GNUTLS_TL_VERIFY_CRL) {

			ret =
			    gnutls_x509_crl_verify(crl_list[i],
						   list->node[hash].
						   trusted_cas,
						   list->node[hash].
						   trusted_ca_size,
						   verification_flags,
						   &vret);
			if (ret < 0 || vret != 0)
				continue;
		}

		list->node[hash].crls =
		    gnutls_realloc_fast(list->node[hash].crls,
					(list->node[hash].crl_size +
					 1) *
					sizeof(list->node[hash].
					       trusted_cas[0]));
		if (list->node[hash].crls == NULL) {
			gnutls_assert();
			return i;
		}

		list->node[hash].crls[list->node[hash].crl_size] =
		    crl_list[i];
		list->node[hash].crl_size++;
		j++;
	}

	return j;
}

/* Takes a certificate list and shortens it if there are
 * intermedia certificates already trusted by us.
 *
 * Returns the new size of the list or a negative number on error.
 */
static int shorten_clist(gnutls_x509_trust_list_t list,
			 gnutls_x509_crt_t * certificate_list,
			 unsigned int clist_size)
{
	unsigned int j, i;
	uint32_t hash;

	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. */
	for (i = 1; i < clist_size; i++) {
		hash =
		    hash_pjw_bare(certificate_list[i]->raw_issuer_dn.data,
				  certificate_list[i]->raw_issuer_dn.size);
		hash %= list->size;

		for (j = 0; j < list->node[hash].trusted_ca_size; j++) {
			if (_gnutls_check_if_same_cert
			    (certificate_list[i],
			     list->node[hash].trusted_cas[j]) != 0) {
				/* cut the list at the point of first the trusted certificate */
				clist_size = i + 1;
				break;
			}
		}
		/* clist_size may have been changed which gets out of loop */
	}

	return clist_size;
}

/* Takes a certificate list and orders it with subject, issuer order.
 *
 * *clist_size contains the size of the ordered list (which is always less or
 * equal to the original).
 *
 * Returns the sorted list which may be the original clist.
 */
static gnutls_x509_crt_t *sort_clist(gnutls_x509_crt_t
				     sorted[DEFAULT_MAX_VERIFY_DEPTH],
				     gnutls_x509_crt_t * clist,
				     unsigned int *clist_size)
{
	int prev;
	unsigned int j, i;
	int issuer[DEFAULT_MAX_VERIFY_DEPTH];	/* contain the index of the issuers */

	/* Do not bother sorting if too many certificates are given.
	 * Prevent any DoS attacks.
	 */
	if (*clist_size > DEFAULT_MAX_VERIFY_DEPTH)
		return clist;

	for (i = 0; i < DEFAULT_MAX_VERIFY_DEPTH; i++)
		issuer[i] = -1;

	/* Find the issuer of each certificate and store it
	 * in issuer array.
	 */
	for (i = 0; i < *clist_size; i++) {
		for (j = 1; j < *clist_size; j++) {
			if (i == j)
				continue;

			if (gnutls_x509_crt_check_issuer(clist[i],
							 clist[j]) != 0) {
				issuer[i] = j;
				break;
			}
		}
	}

	if (issuer[0] == -1) {
		*clist_size = 1;
		return clist;
	}

	prev = 0;
	sorted[0] = clist[0];
	for (i = 1; i < *clist_size; i++) {
		prev = issuer[prev];
		if (prev == -1) {	/* no issuer */
			*clist_size = i;
			break;
		}
		sorted[i] = clist[prev];
	}

	return sorted;
}

static
int trust_list_get_issuer(gnutls_x509_trust_list_t list,
				      gnutls_x509_crt_t cert,
				      gnutls_x509_crt_t * issuer,
				      unsigned int flags)
{
	int ret;
	unsigned int i;
	uint32_t hash;

	hash =
	    hash_pjw_bare(cert->raw_issuer_dn.data,
			  cert->raw_issuer_dn.size);
	hash %= list->size;

	for (i = 0; i < list->node[hash].trusted_ca_size; i++) {
		ret =
		    gnutls_x509_crt_check_issuer(cert,
						 list->node[hash].
						 trusted_cas[i]);
		if (ret != 0) {
			*issuer = list->node[hash].trusted_cas[i];
			return 0;
		}
	}

	return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
}

/**
 * gnutls_x509_trust_list_get_issuer:
 * @list: The structure of the list
 * @cert: is the certificate to find issuer for
 * @issuer: Will hold the issuer if any. Should be treated as constant.
 * @flags: Use zero.
 *
 * This function will attempt to find the issuer of the
 * given certificate.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0
 **/
int gnutls_x509_trust_list_get_issuer(gnutls_x509_trust_list_t list,
				      gnutls_x509_crt_t cert,
				      gnutls_x509_crt_t * issuer,
				      unsigned int flags)
{
#ifdef ENABLE_PKCS11
	int ret;

	if (list->pkcs11_token) {
		gnutls_datum_t der = {NULL, 0};
		/* use the token for verification */
		ret = gnutls_pkcs11_get_raw_issuer(list->pkcs11_token, cert, &der,
			GNUTLS_X509_FMT_DER, 0);
		if (ret < 0)
			return gnutls_assert_val(ret);

		/* we add this CA to the trusted list in order to make it
		 * persistent. It will be deallocated when the trust list is.
		 */
		ret = gnutls_x509_trust_list_add_trust_mem(list, &der, NULL,
			GNUTLS_X509_FMT_DER, GNUTLS_TL_NO_DUPLICATES, 0);
		if (ret < 0)
			return gnutls_assert_val(ret);

		gnutls_free(der.data);
	}
#endif

	return trust_list_get_issuer(list, cert, issuer, flags);
}

static
int check_if_in_blacklist(gnutls_x509_crt_t * cert_list, unsigned int cert_list_size,
	gnutls_x509_crt_t * blacklist, unsigned int blacklist_size)
{
unsigned i, j;

	if (blacklist_size == 0)
		return 0;

	for (i=0;i<cert_list_size;i++) {
		for (j=0;j<blacklist_size;j++) {
			if (_gnutls_check_if_same_cert(cert_list[i], blacklist[j]) != 0) {
				return 1;
			}
		}
	}

	return 0;
}

/**
 * gnutls_x509_trust_list_verify_crt:
 * @list: The structure of the list
 * @cert_list: is the certificate list to be verified
 * @cert_list_size: is the certificate list size
 * @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
 * @voutput: will hold the certificate verification output.
 * @func: If non-null will be called on each chain element verification with the output.
 *
 * This function will try to verify the given certificate and return
 * its status. The @verify parameter will hold an OR'ed sequence of
 * %gnutls_certificate_status_t flags.
 *
 * Additionally a certificate verification profile can be specified
 * from the ones in %gnutls_certificate_verification_profiles_t by
 * ORing the result of GNUTLS_PROFILE_TO_VFLAGS() to the verification
 * flags.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0
 **/
int
gnutls_x509_trust_list_verify_crt(gnutls_x509_trust_list_t list,
				  gnutls_x509_crt_t * cert_list,
				  unsigned int cert_list_size,
				  unsigned int flags,
				  unsigned int *voutput,
				  gnutls_verify_output_function func)
{
	return gnutls_x509_trust_list_verify_crt2(list, cert_list, cert_list_size,
						  NULL, 0, flags, voutput, func);
}

static
int check_key_purpose(gnutls_x509_crt_t crt, const gnutls_datum_t *ext_data, unsigned *voutput, 
		      const char *purpose)
{
	gnutls_datum_t coid = {NULL, 0};
	gnutls_x509_key_purposes_t p = NULL;
	unsigned i;
	int ret;

	ret = gnutls_x509_key_purpose_init(&p);
	if (ret < 0) {
		gnutls_assert();
		goto fail;
	}

	ret = gnutls_x509_ext_import_key_purposes(ext_data, p, 0);
	if (ret < 0) {
		gnutls_assert();
		goto fail;
	}

	for (i=0;;i++) {
		ret = gnutls_x509_key_purpose_get(p, i, &coid);
		if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
			if (i==0) {
				break;
			} else { /* no acceptable purpose was found */
				gnutls_assert();
				goto fail;
			}
		} else if (ret < 0) {
			gnutls_assert();
			goto fail;
		}

		if (strcmp((char*)coid.data, purpose) == 0 || strcmp((char*)coid.data, GNUTLS_KP_ANY) == 0)
			break;
	}

	gnutls_x509_key_purpose_deinit(p);
	return 0;
 fail:
	*voutput |= GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE|GNUTLS_CERT_INVALID;
	if (p != NULL)
		gnutls_x509_key_purpose_deinit(p);
	return ret;
}

/**
 * gnutls_x509_trust_list_verify_crt2:
 * @list: The structure of the list
 * @cert_list: is the certificate list to be verified
 * @cert_list_size: is the certificate list size
 * @data: an array of typed data
 * @elements: the number of data elements
 * @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
 * @voutput: will hold the certificate verification output.
 * @func: If non-null will be called on each chain element verification with the output.
 *
 * This function will try to verify the given certificate and return
 * its status. The @verify parameter will hold an OR'ed sequence of
 * %gnutls_certificate_status_t flags.
 *
 * Additionally a certificate verification profile can be specified
 * from the ones in %gnutls_certificate_verification_profiles_t by
 * ORing the result of GNUTLS_PROFILE_TO_VFLAGS() to the verification
 * flags.
 *
 * The acceptable @data types are %GNUTLS_DT_DNS_HOSTNAME and %GNUTLS_DT_KEY_PURPOSE_OID.
 * The former accepts as data a null-terminated hostname, and the latter a null-terminated
 * object identifier (e.g., %GNUTLS_KP_TLS_WWW_SERVER).
 * If a DNS hostname is provided then this function will compare
 * the hostname in the certificate against the given. If names do not match the 
 * %GNUTLS_CERT_UNEXPECTED_OWNER status flag will be set.
 * If a key purpose OID is provided and the end-certificate contains the extended key
 * usage PKIX extension, it will be required to be have the provided key purpose 
 * or be marked for any purpose, otherwise verification will fail with %GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE status.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value. Note that verification failure will not result to an
 *   error code, only @voutput will be updated.
 *
 * Since: 3.3.8
 **/
int
gnutls_x509_trust_list_verify_crt2(gnutls_x509_trust_list_t list,
				  gnutls_x509_crt_t * cert_list,
				  unsigned int cert_list_size,
				  gnutls_typed_vdata_st *data,
				  unsigned int elements,
				  unsigned int flags,
				  unsigned int *voutput,
				  gnutls_verify_output_function func)
{
	int ret;
	unsigned int i;
	uint32_t hash;
	gnutls_x509_crt_t sorted[DEFAULT_MAX_VERIFY_DEPTH];
	const char *hostname = NULL, *purpose = NULL;

	if (cert_list == NULL || cert_list_size < 1)
		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	for (i=0;i<elements;i++) {
		if (data[i].type == GNUTLS_DT_DNS_HOSTNAME) {
			hostname = (void*)data[i].data;
		} else if (data[i].type == GNUTLS_DT_KEY_PURPOSE_OID) {
			purpose = (void*)data[i].data;
		}
	}

	if (!(flags & GNUTLS_VERIFY_DO_NOT_ALLOW_UNSORTED_CHAIN))
		cert_list = sort_clist(sorted, cert_list, &cert_list_size);

	cert_list_size = shorten_clist(list, cert_list, cert_list_size);
	if (cert_list_size <= 0)
		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

	hash =
	    hash_pjw_bare(cert_list[cert_list_size - 1]->raw_issuer_dn.
			  data,
			  cert_list[cert_list_size -
				    1]->raw_issuer_dn.size);
	hash %= list->size;

	ret = check_if_in_blacklist(cert_list, cert_list_size,
		list->blacklisted, list->blacklisted_size);
	if (ret != 0) {
		*voutput = 0;
		*voutput |= GNUTLS_CERT_REVOKED;
		*voutput |= GNUTLS_CERT_INVALID;
		return 0;
	}

#ifdef ENABLE_PKCS11
	if (list->pkcs11_token) {
		/* use the token for verification */

		*voutput = _gnutls_pkcs11_verify_crt_status(list->pkcs11_token,
								cert_list, cert_list_size,
								purpose!=NULL?purpose:GNUTLS_KP_TLS_WWW_SERVER,
								flags, func);
	} else
#endif
	{
		*voutput =
		    _gnutls_verify_crt_status(cert_list, cert_list_size,
						    list->node[hash].trusted_cas,
						    list->
						    node[hash].trusted_ca_size,
						    flags, func);

#define LAST_DN cert_list[cert_list_size-1]->raw_dn
#define LAST_IDN cert_list[cert_list_size-1]->raw_issuer_dn

		if ((*voutput) & GNUTLS_CERT_SIGNER_NOT_FOUND &&
			(LAST_DN.size != LAST_IDN.size ||
			 memcmp(LAST_DN.data, LAST_IDN.data, LAST_IDN.size) != 0)) {

			/* if we couldn't find the issuer, try to see if the last
			 * certificate is in the trusted list and try to verify against
			 * (if it is not self signed) */
			hash =
			    hash_pjw_bare(cert_list[cert_list_size - 1]->raw_dn.
				  data, cert_list[cert_list_size - 1]->raw_dn.size);
			hash %= list->size;

			*voutput =
			    _gnutls_verify_crt_status(cert_list, cert_list_size,
						    list->node[hash].trusted_cas,
						    list->
						    node[hash].trusted_ca_size,
						    flags, func);
		}
	}

	if (*voutput != 0 || (flags & GNUTLS_VERIFY_DISABLE_CRL_CHECKS))
		return 0;

	/* Check revocation of individual certificates.
	 * start with the last one that we already have its hash
	 */
	ret =
	    _gnutls_x509_crt_check_revocation(cert_list
					      [cert_list_size - 1],
					      list->node[hash].crls,
					      list->node[hash].crl_size,
					      func);
	if (ret == 1) {		/* revoked */
		*voutput |= GNUTLS_CERT_REVOKED;
		*voutput |= GNUTLS_CERT_INVALID;
		return 0;
	}

	for (i = 0; i < cert_list_size - 1; i++) {
		hash =
		    hash_pjw_bare(cert_list[i]->raw_issuer_dn.data,
				  cert_list[i]->raw_issuer_dn.size);
		hash %= list->size;

		ret = _gnutls_x509_crt_check_revocation(cert_list[i],
							list->node[hash].
							crls,
							list->node[hash].
							crl_size, func);
		if (ret < 0) {
			gnutls_assert();
		} else if (ret == 1) {	/* revoked */
			*voutput |= GNUTLS_CERT_REVOKED;
			*voutput |= GNUTLS_CERT_INVALID;
			return 0;
		}
	}

	/* check the purpose if given */
	if (purpose) do {
		gnutls_datum_t ext_data = {NULL, 0};

		ret = gnutls_x509_crt_get_extension_by_oid2(cert_list[0], "2.5.29.37", 0, &ext_data, NULL);
		if (ret < 0) {
			/* it's not a fatal error if the extended key usage extension isn't there */
			gnutls_assert();
			break;
		}

		ret = check_key_purpose(cert_list[0], &ext_data, voutput, purpose);
		gnutls_free(ext_data.data);

		if (ret < 0) {
			gnutls_assert();
		}
	} while(0);

	if (hostname) {
		ret =
		    gnutls_x509_crt_check_hostname2(cert_list[0], hostname, flags);
		if (ret == 0)
			*voutput |= GNUTLS_CERT_UNEXPECTED_OWNER|GNUTLS_CERT_INVALID;
	}

	return 0;
}

/**
 * gnutls_x509_trust_list_verify_named_crt:
 * @list: The structure of the list
 * @cert: is the certificate to be verified
 * @name: is the certificate's name
 * @name_size: is the certificate's name size
 * @flags: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
 * @voutput: will hold the certificate verification output.
 * @func: If non-null will be called on each chain element verification with the output.
 *
 * This function will try to find a certificate that is associated with the provided
 * name --see gnutls_x509_trust_list_add_named_crt(). If a match is found the certificate is considered valid. 
 * In addition to that this function will also check CRLs. 
 * The @voutput parameter will hold an OR'ed sequence of %gnutls_certificate_status_t flags.
 *
 * Additionally a certificate verification profile can be specified
 * from the ones in %gnutls_certificate_verification_profiles_t by
 * ORing the result of GNUTLS_PROFILE_TO_VFLAGS() to the verification
 * flags.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0.0
 **/
int
gnutls_x509_trust_list_verify_named_crt(gnutls_x509_trust_list_t list,
					gnutls_x509_crt_t cert,
					const void *name,
					size_t name_size,
					unsigned int flags,
					unsigned int *voutput,
					gnutls_verify_output_function func)
{
	int ret;
	unsigned int i;
	uint32_t hash;


	hash =
	    hash_pjw_bare(cert->raw_issuer_dn.data,
			  cert->raw_issuer_dn.size);
	hash %= list->size;

	ret = check_if_in_blacklist(&cert, 1,
		list->blacklisted, list->blacklisted_size);
	if (ret != 0) {
		*voutput = 0;
		*voutput |= GNUTLS_CERT_REVOKED;
		*voutput |= GNUTLS_CERT_INVALID;
		return 0;
	}

	*voutput = GNUTLS_CERT_INVALID | GNUTLS_CERT_SIGNER_NOT_FOUND;

	for (i = 0; i < list->node[hash].named_cert_size; i++) {
		if (_gnutls_check_if_same_cert(cert, list->node[hash].named_certs[i].cert) != 0) {	/* check if name matches */
			if (list->node[hash].named_certs[i].name_size ==
			    name_size
			    && memcmp(list->node[hash].named_certs[i].name,
				      name, name_size) == 0) {
				*voutput = 0;
				break;
			}
		}
	}

	if (*voutput != 0 || (flags & GNUTLS_VERIFY_DISABLE_CRL_CHECKS))
		return 0;

	/* Check revocation of individual certificates.
	 * start with the last one that we already have its hash
	 */
	ret = _gnutls_x509_crt_check_revocation(cert,
						list->node[hash].crls,
						list->node[hash].crl_size,
						func);
	if (ret == 1) {		/* revoked */
		*voutput |= GNUTLS_CERT_REVOKED;
		*voutput |= GNUTLS_CERT_INVALID;
		return 0;
	}

	return 0;
}

/* return 1 if @cert is in @list, 0 if not */
int
_gnutls_trustlist_inlist(gnutls_x509_trust_list_t list,
			 gnutls_x509_crt_t cert)
{
	int ret;
	unsigned int i;
	uint32_t hash;

	hash = hash_pjw_bare(cert->raw_dn.data, cert->raw_dn.size);
	hash %= list->size;

	for (i = 0; i < list->node[hash].trusted_ca_size; i++) {
		ret =
		    _gnutls_check_if_same_cert(cert,
					       list->node[hash].
					       trusted_cas[i]);
		if (ret != 0)
			return 1;
	}

	return 0;
}