/* ocsp_vfy.c */

 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) 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 */

 EXPORT_C 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.

  */

 EXPORT_C 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;

 	}