src/parsec/disk-image/parsec/parsec-benchmark/pkgs/libs/ssl/src/crypto/ocsp/ocsp_vfy.c - public/gem5-resources - Git at Google

 /* ocsp_vfy.c */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2000.
  */
 /* ====================================================================
  * Copyright (c) 2000-2004 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. All advertising materials mentioning features or use of this
  *    software must display the following acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  *
  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  *    endorse or promote products derived from this software without
  *    prior written permission. For written permission, please contact
  *    licensing@OpenSSL.org.
  *
  * 5. Products derived from this software may not be called "OpenSSL"
  *    nor may "OpenSSL" appear in their names without prior written
  *    permission of the OpenSSL Project.
  *
  * 6. Redistributions of any form whatsoever must retain the following
  *    acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  *
  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  * ====================================================================
  *
  * This product includes cryptographic software written by Eric Young
  * (eay@cryptsoft.com).  This product includes software written by Tim
  * Hudson (tjh@cryptsoft.com).
  *
  */

 #include <openssl/ocsp.h>
 #include <openssl/err.h>
 #include <string.h>

 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
 				X509_STORE *st, unsigned long flags);
 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags);
 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret);
 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp);
 static int ocsp_check_delegated(X509 *x, int flags);
 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
 				X509_STORE *st, unsigned long flags);

 /* Verify a basic response message */

 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
 				X509_STORE *st, unsigned long flags)
 	{
 	X509 *signer, *x;
 	STACK_OF(X509) *chain = NULL;
 	X509_STORE_CTX ctx;
 	int i, ret = 0;
 	ret = ocsp_find_signer(&signer, bs, certs, st, flags);
 	if (!ret)
 		{
 		OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 		goto end;
 		}
 	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 		flags |= OCSP_NOVERIFY;
 	if (!(flags & OCSP_NOSIGS))
 		{
 		EVP_PKEY *skey;
 		skey = X509_get_pubkey(signer);
 		ret = OCSP_BASICRESP_verify(bs, skey, 0);
 		EVP_PKEY_free(skey);
 		if(ret <= 0)
 			{
 			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 			goto end;
 			}
 		}
 	if (!(flags & OCSP_NOVERIFY))
 		{
 		int init_res;
 		if(flags & OCSP_NOCHAIN)
 			init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL);
 		else
 			init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
 		if(!init_res)
 			{
 			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
 			goto end;
 			}

 		X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 		ret = X509_verify_cert(&ctx);
 		chain = X509_STORE_CTX_get1_chain(&ctx);
 		X509_STORE_CTX_cleanup(&ctx);
                 if (ret <= 0)
 			{
 			i = X509_STORE_CTX_get_error(&ctx);
 			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 			ERR_add_error_data(2, "Verify error:",
 					X509_verify_cert_error_string(i));
                         goto end;
                 	}
 		if(flags & OCSP_NOCHECKS)
 			{
 			ret = 1;
 			goto end;
 			}
 		/* At this point we have a valid certificate chain
 		 * need to verify it against the OCSP issuer criteria.
 		 */
 		ret = ocsp_check_issuer(bs, chain, flags);

 		/* If fatal error or valid match then finish */
 		if (ret != 0) goto end;

 		/* Easy case: explicitly trusted. Get root CA and
 		 * check for explicit trust
 		 */
 		if(flags & OCSP_NOEXPLICIT) goto end;

 		x = sk_X509_value(chain, sk_X509_num(chain) - 1);
 		if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
 			{
 			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
 			goto end;
 			}
 		ret = 1;
 		}


 	end:
 	if(chain) sk_X509_pop_free(chain, X509_free);
 	return ret;
 	}


 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
 				X509_STORE *st, unsigned long flags)
 	{
 	X509 *signer;
 	OCSP_RESPID *rid = bs->tbsResponseData->responderId;
 	if ((signer = ocsp_find_signer_sk(certs, rid)))
 		{
 		*psigner = signer;
 		return 2;
 		}
 	if(!(flags & OCSP_NOINTERN) &&
 	    (signer = ocsp_find_signer_sk(bs->certs, rid)))
 		{
 		*psigner = signer;
 		return 1;
 		}
 	/* Maybe lookup from store if by subject name */

 	*psigner = NULL;
 	return 0;
 	}


 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
 	{
 	int i;
 	unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
 	X509 *x;

 	/* Easy if lookup by name */
 	if (id->type == V_OCSP_RESPID_NAME)
 		return X509_find_by_subject(certs, id->value.byName);

 	/* Lookup by key hash */

 	/* If key hash isn't SHA1 length then forget it */
 	if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
 	keyhash = id->value.byKey->data;
 	/* Calculate hash of each key and compare */
 	for (i = 0; i < sk_X509_num(certs); i++)
 		{
 		x = sk_X509_value(certs, i);
 		X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
 		if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
 			return x;
 		}
 	return NULL;
 	}


 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
 	{
 	STACK_OF(OCSP_SINGLERESP) *sresp;
 	X509 *signer, *sca;
 	OCSP_CERTID *caid = NULL;
 	int i;
 	sresp = bs->tbsResponseData->responses;

 	if (sk_X509_num(chain) <= 0)
 		{
 		OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
 		return -1;
 		}

 	/* See if the issuer IDs match. */
 	i = ocsp_check_ids(sresp, &caid);

 	/* If ID mismatch or other error then return */
 	if (i <= 0) return i;

 	signer = sk_X509_value(chain, 0);
 	/* Check to see if OCSP responder CA matches request CA */
 	if (sk_X509_num(chain) > 1)
 		{
 		sca = sk_X509_value(chain, 1);
 		i = ocsp_match_issuerid(sca, caid, sresp);
 		if (i < 0) return i;
 		if (i)
 			{
 			/* We have a match, if extensions OK then success */
 			if (ocsp_check_delegated(signer, flags)) return 1;
 			return 0;
 			}
 		}

 	/* Otherwise check if OCSP request signed directly by request CA */
 	return ocsp_match_issuerid(signer, caid, sresp);
 	}


 /* Check the issuer certificate IDs for equality. If there is a mismatch with the same
  * algorithm then there's no point trying to match any certificates against the issuer.
  * If the issuer IDs all match then we just need to check equality against one of them.
  */

 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
 	{
 	OCSP_CERTID *tmpid, *cid;
 	int i, idcount;

 	idcount = sk_OCSP_SINGLERESP_num(sresp);
 	if (idcount <= 0)
 		{
 		OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
 		return -1;
 		}

 	cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;

 	*ret = NULL;

 	for (i = 1; i < idcount; i++)
 		{
 		tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 		/* Check to see if IDs match */
 		if (OCSP_id_issuer_cmp(cid, tmpid))
 			{
 			/* If algoritm mismatch let caller deal with it */
 			if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
 					cid->hashAlgorithm->algorithm))
 					return 2;
 			/* Else mismatch */
 			return 0;
 			}
 		}

 	/* All IDs match: only need to check one ID */
 	*ret = cid;
 	return 1;
 	}


 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
 			STACK_OF(OCSP_SINGLERESP) *sresp)
 	{
 	/* If only one ID to match then do it */
 	if(cid)
 		{
 		const EVP_MD *dgst;
 		X509_NAME *iname;
 		int mdlen;
 		unsigned char md[EVP_MAX_MD_SIZE];
 		if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
 			{
 			OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
 			return -1;
 			}

 		mdlen = EVP_MD_size(dgst);
 		if ((cid->issuerNameHash->length != mdlen) ||
 		   (cid->issuerKeyHash->length != mdlen))
 			return 0;
 		iname = X509_get_subject_name(cert);
 		if (!X509_NAME_digest(iname, dgst, md, NULL))
 			return -1;
 		if (memcmp(md, cid->issuerNameHash->data, mdlen))
 			return 0;
 		X509_pubkey_digest(cert, EVP_sha1(), md, NULL);
 		if (memcmp(md, cid->issuerKeyHash->data, mdlen))
 			return 0;

 		return 1;

 		}
 	else
 		{
 		/* We have to match the whole lot */
 		int i, ret;
 		OCSP_CERTID *tmpid;
 		for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
 			{
 			tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 			ret = ocsp_match_issuerid(cert, tmpid, NULL);
 			if (ret <= 0) return ret;
 			}
 		return 1;
 		}

 	}

 static int ocsp_check_delegated(X509 *x, int flags)
 	{
 	X509_check_purpose(x, -1, 0);
 	if ((x->ex_flags & EXFLAG_XKUSAGE) &&
 	    (x->ex_xkusage & XKU_OCSP_SIGN))
 		return 1;
 	OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
 	return 0;
 	}

 /* Verify an OCSP request. This is fortunately much easier than OCSP
  * response verify. Just find the signers certificate and verify it
  * against a given trust value.
  */

 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags)
         {
 	X509 *signer;
 	X509_NAME *nm;
 	GENERAL_NAME *gen;
 	int ret;
 	X509_STORE_CTX ctx;
 	if (!req->optionalSignature)
 		{
 		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
 		return 0;
 		}
 	gen = req->tbsRequest->requestorName;
 	if (!gen || gen->type != GEN_DIRNAME)
 		{
 		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
 		return 0;
 		}
 	nm = gen->d.directoryName;
 	ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
 	if (ret <= 0)
 		{
 		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 		return 0;
 		}
 	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 		flags |= OCSP_NOVERIFY;
 	if (!(flags & OCSP_NOSIGS))
 		{
 		EVP_PKEY *skey;
 		skey = X509_get_pubkey(signer);
 		ret = OCSP_REQUEST_verify(req, skey);
 		EVP_PKEY_free(skey);
 		if(ret <= 0)
 			{
 			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 			return 0;
 			}
 		}
 	if (!(flags & OCSP_NOVERIFY))
 		{
 		int init_res;
 		if(flags & OCSP_NOCHAIN)
 			init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
 		else
 			init_res = X509_STORE_CTX_init(&ctx, store, signer,
 					req->optionalSignature->certs);
 		if(!init_res)
 			{
 			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB);
 			return 0;
 			}

 		X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 		X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
 		ret = X509_verify_cert(&ctx);
 		X509_STORE_CTX_cleanup(&ctx);
                 if (ret <= 0)
 			{
 			ret = X509_STORE_CTX_get_error(&ctx);
 			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 			ERR_add_error_data(2, "Verify error:",
 					X509_verify_cert_error_string(ret));
                         return 0;
                 	}
 		}
 	return 1;
         }

 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
 				X509_STORE *st, unsigned long flags)
 	{
 	X509 *signer;
 	if(!(flags & OCSP_NOINTERN))
 		{
 		signer = X509_find_by_subject(req->optionalSignature->certs, nm);
 		*psigner = signer;
 		return 1;
 		}

 	signer = X509_find_by_subject(certs, nm);
 	if (signer)
 		{
 		*psigner = signer;
 		return 2;
 		}
 	return 0;
 	}
	/* ocsp_vfy.c */
	/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
	* project 2000.
	*/
	/* ====================================================================
	* Copyright (c) 2000-2004 The OpenSSL Project. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. All advertising materials mentioning features or use of this
	* software must display the following acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
	*
	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For written permission, please contact
	* licensing@OpenSSL.org.
	*
	* 5. Products derived from this software may not be called "OpenSSL"
	* nor may "OpenSSL" appear in their names without prior written
	* permission of the OpenSSL Project.
	*
	* 6. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
	*
	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	* OF THE POSSIBILITY OF SUCH DAMAGE.
	* ====================================================================
	*
	* This product includes cryptographic software written by Eric Young
	* (eay@cryptsoft.com). This product includes software written by Tim
	* Hudson (tjh@cryptsoft.com).
	*
	*/

	#include <openssl/ocsp.h>
	#include <openssl/err.h>
	#include <string.h>

	static int ocsp_find_signer(X509 *psigner, OCSP_BASICRESP bs, STACK_OF(X509) *certs,
	X509_STORE *st, unsigned long flags);
	static X509 ocsp_find_signer_sk(STACK_OF(X509) certs, OCSP_RESPID *id);
	static int ocsp_check_issuer(OCSP_BASICRESP bs, STACK_OF(X509) chain, unsigned long flags);
	static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) sresp, OCSP_CERTID *ret);
	static int ocsp_match_issuerid(X509 cert, OCSP_CERTID cid, STACK_OF(OCSP_SINGLERESP) *sresp);
	static int ocsp_check_delegated(X509 *x, int flags);
	static int ocsp_req_find_signer(X509 *psigner, OCSP_REQUEST req, X509_NAME nm, STACK_OF(X509) certs,
	X509_STORE *st, unsigned long flags);

	/* Verify a basic response message */

	int OCSP_basic_verify(OCSP_BASICRESP bs, STACK_OF(X509) certs,
	X509_STORE *st, unsigned long flags)
	{
	X509 signer, x;
	STACK_OF(X509) *chain = NULL;
	X509_STORE_CTX ctx;
	int i, ret = 0;
	ret = ocsp_find_signer(&signer, bs, certs, st, flags);
	if (!ret)
	{
	OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
	goto end;
	}
	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
	flags \|= OCSP_NOVERIFY;
	if (!(flags & OCSP_NOSIGS))
	{
	EVP_PKEY *skey;
	skey = X509_get_pubkey(signer);
	ret = OCSP_BASICRESP_verify(bs, skey, 0);
	EVP_PKEY_free(skey);
	if(ret <= 0)
	{
	OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
	goto end;
	}
	}
	if (!(flags & OCSP_NOVERIFY))
	{
	int init_res;
	if(flags & OCSP_NOCHAIN)
	init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL);
	else
	init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
	if(!init_res)
	{
	OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
	goto end;
	}

	X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
	ret = X509_verify_cert(&ctx);
	chain = X509_STORE_CTX_get1_chain(&ctx);
	X509_STORE_CTX_cleanup(&ctx);
	if (ret <= 0)
	{
	i = X509_STORE_CTX_get_error(&ctx);
	OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
	ERR_add_error_data(2, "Verify error:",
	X509_verify_cert_error_string(i));
	goto end;
	}
	if(flags & OCSP_NOCHECKS)
	{
	ret = 1;
	goto end;
	}
	/* At this point we have a valid certificate chain
	* need to verify it against the OCSP issuer criteria.
	*/
	ret = ocsp_check_issuer(bs, chain, flags);

	/* If fatal error or valid match then finish */
	if (ret != 0) goto end;

	/* Easy case: explicitly trusted. Get root CA and
	* check for explicit trust
	*/
	if(flags & OCSP_NOEXPLICIT) goto end;

	x = sk_X509_value(chain, sk_X509_num(chain) - 1);
	if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
	{
	OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
	goto end;
	}
	ret = 1;
	}



	end:
	if(chain) sk_X509_pop_free(chain, X509_free);
	return ret;
	}


	static int ocsp_find_signer(X509 *psigner, OCSP_BASICRESP bs, STACK_OF(X509) *certs,
	X509_STORE *st, unsigned long flags)
	{
	X509 *signer;
	OCSP_RESPID *rid = bs->tbsResponseData->responderId;
	if ((signer = ocsp_find_signer_sk(certs, rid)))
	{
	*psigner = signer;
	return 2;
	}
	if(!(flags & OCSP_NOINTERN) &&
	(signer = ocsp_find_signer_sk(bs->certs, rid)))
	{
	*psigner = signer;
	return 1;
	}
	/* Maybe lookup from store if by subject name */

	*psigner = NULL;
	return 0;
	}


	static X509 ocsp_find_signer_sk(STACK_OF(X509) certs, OCSP_RESPID *id)
	{
	int i;
	unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
	X509 *x;

	/* Easy if lookup by name */
	if (id->type == V_OCSP_RESPID_NAME)
	return X509_find_by_subject(certs, id->value.byName);

	/* Lookup by key hash */

	/* If key hash isn't SHA1 length then forget it */
	if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
	keyhash = id->value.byKey->data;
	/* Calculate hash of each key and compare */
	for (i = 0; i < sk_X509_num(certs); i++)
	{
	x = sk_X509_value(certs, i);
	X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
	if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
	return x;
	}
	return NULL;
	}


	static int ocsp_check_issuer(OCSP_BASICRESP bs, STACK_OF(X509) chain, unsigned long flags)
	{
	STACK_OF(OCSP_SINGLERESP) *sresp;
	X509 signer, sca;
	OCSP_CERTID *caid = NULL;
	int i;
	sresp = bs->tbsResponseData->responses;

	if (sk_X509_num(chain) <= 0)
	{
	OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
	return -1;
	}

	/* See if the issuer IDs match. */
	i = ocsp_check_ids(sresp, &caid);

	/* If ID mismatch or other error then return */
	if (i <= 0) return i;

	signer = sk_X509_value(chain, 0);
	/* Check to see if OCSP responder CA matches request CA */
	if (sk_X509_num(chain) > 1)
	{
	sca = sk_X509_value(chain, 1);
	i = ocsp_match_issuerid(sca, caid, sresp);
	if (i < 0) return i;
	if (i)
	{
	/* We have a match, if extensions OK then success */
	if (ocsp_check_delegated(signer, flags)) return 1;
	return 0;
	}
	}

	/* Otherwise check if OCSP request signed directly by request CA */
	return ocsp_match_issuerid(signer, caid, sresp);
	}


	/* Check the issuer certificate IDs for equality. If there is a mismatch with the same
	* algorithm then there's no point trying to match any certificates against the issuer.
	* If the issuer IDs all match then we just need to check equality against one of them.
	*/

	static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) sresp, OCSP_CERTID *ret)
	{
	OCSP_CERTID tmpid, cid;
	int i, idcount;

	idcount = sk_OCSP_SINGLERESP_num(sresp);
	if (idcount <= 0)
	{
	OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
	return -1;
	}

	cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;

	*ret = NULL;

	for (i = 1; i < idcount; i++)
	{
	tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
	/* Check to see if IDs match */
	if (OCSP_id_issuer_cmp(cid, tmpid))
	{
	/* If algoritm mismatch let caller deal with it */
	if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
	cid->hashAlgorithm->algorithm))
	return 2;
	/* Else mismatch */
	return 0;
	}
	}

	/* All IDs match: only need to check one ID */
	*ret = cid;
	return 1;
	}


	static int ocsp_match_issuerid(X509 cert, OCSP_CERTID cid,
	STACK_OF(OCSP_SINGLERESP) *sresp)
	{
	/* If only one ID to match then do it */
	if(cid)
	{
	const EVP_MD *dgst;
	X509_NAME *iname;
	int mdlen;
	unsigned char md[EVP_MAX_MD_SIZE];
	if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
	{
	OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
	return -1;
	}

	mdlen = EVP_MD_size(dgst);
	if ((cid->issuerNameHash->length != mdlen) \|\|
	(cid->issuerKeyHash->length != mdlen))
	return 0;
	iname = X509_get_subject_name(cert);
	if (!X509_NAME_digest(iname, dgst, md, NULL))
	return -1;
	if (memcmp(md, cid->issuerNameHash->data, mdlen))
	return 0;
	X509_pubkey_digest(cert, EVP_sha1(), md, NULL);
	if (memcmp(md, cid->issuerKeyHash->data, mdlen))
	return 0;

	return 1;

	}
	else
	{
	/* We have to match the whole lot */
	int i, ret;
	OCSP_CERTID *tmpid;
	for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
	{
	tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
	ret = ocsp_match_issuerid(cert, tmpid, NULL);
	if (ret <= 0) return ret;
	}
	return 1;
	}

	}

	static int ocsp_check_delegated(X509 *x, int flags)
	{
	X509_check_purpose(x, -1, 0);
	if ((x->ex_flags & EXFLAG_XKUSAGE) &&
	(x->ex_xkusage & XKU_OCSP_SIGN))
	return 1;
	OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
	return 0;
	}

	/* Verify an OCSP request. This is fortunately much easier than OCSP
	* response verify. Just find the signers certificate and verify it
	* against a given trust value.
	*/

	int OCSP_request_verify(OCSP_REQUEST req, STACK_OF(X509) certs, X509_STORE *store, unsigned long flags)
	{
	X509 *signer;
	X509_NAME *nm;
	GENERAL_NAME *gen;
	int ret;
	X509_STORE_CTX ctx;
	if (!req->optionalSignature)
	{
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
	return 0;
	}
	gen = req->tbsRequest->requestorName;
	if (!gen \|\| gen->type != GEN_DIRNAME)
	{
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
	return 0;
	}
	nm = gen->d.directoryName;
	ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
	if (ret <= 0)
	{
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
	return 0;
	}
	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
	flags \|= OCSP_NOVERIFY;
	if (!(flags & OCSP_NOSIGS))
	{
	EVP_PKEY *skey;
	skey = X509_get_pubkey(signer);
	ret = OCSP_REQUEST_verify(req, skey);
	EVP_PKEY_free(skey);
	if(ret <= 0)
	{
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
	return 0;
	}
	}
	if (!(flags & OCSP_NOVERIFY))
	{
	int init_res;
	if(flags & OCSP_NOCHAIN)
	init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
	else
	init_res = X509_STORE_CTX_init(&ctx, store, signer,
	req->optionalSignature->certs);
	if(!init_res)
	{
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB);
	return 0;
	}

	X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
	X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
	ret = X509_verify_cert(&ctx);
	X509_STORE_CTX_cleanup(&ctx);
	if (ret <= 0)
	{
	ret = X509_STORE_CTX_get_error(&ctx);
	OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
	ERR_add_error_data(2, "Verify error:",
	X509_verify_cert_error_string(ret));
	return 0;
	}
	}
	return 1;
	}

	static int ocsp_req_find_signer(X509 *psigner, OCSP_REQUEST req, X509_NAME nm, STACK_OF(X509) certs,
	X509_STORE *st, unsigned long flags)
	{
	X509 *signer;
	if(!(flags & OCSP_NOINTERN))
	{
	signer = X509_find_by_subject(req->optionalSignature->certs, nm);
	*psigner = signer;
	return 1;
	}

	signer = X509_find_by_subject(certs, nm);
	if (signer)
	{
	*psigner = signer;
	return 2;
	}
	return 0;
	}