crypto/ocsp/ocsp_vfy.c

   1 /* ocsp_vfy.c */
   2 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
   3  * project 2000.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2000 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59 #include <openssl/ocsp.h>
  60 #include <openssl/err.h>
  61 #include <string.h>
  62
  63 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
  64                                 X509_STORE *st, unsigned long flags);
  65 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
  66 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags);
  67 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret);
  68 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp);
  69 static int ocsp_check_delegated(X509 *x, int flags);
  70 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
  71                                 X509_STORE *st, unsigned long flags);
  72
  73 /* Verify a basic response message */
  74
  75 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
  76                                 X509_STORE *st, unsigned long flags)
  77         {
  78         X509 *signer, *x;
  79         STACK_OF(X509) *chain = NULL;
  80         X509_STORE_CTX ctx;
  81         int i, ret = 0;
  82         ret = ocsp_find_signer(&signer, bs, certs, st, flags);
  83         if (!ret)
  84                 {
  85                 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
  86                 goto end;
  87                 }
  88         if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
  89                 flags |= OCSP_NOVERIFY;
  90         if (!(flags & OCSP_NOSIGS))
  91                 {
  92                 EVP_PKEY *skey;
  93                 skey = X509_get_pubkey(signer);
  94                 ret = OCSP_BASICRESP_verify(bs, skey, 0);
  95                 EVP_PKEY_free(skey);
  96                 if(ret <= 0)
  97                         {
  98                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
  99                         goto end;
 100                         }
 101                 }
 102         if (!(flags & OCSP_NOVERIFY))
 103                 {
 104                 if(flags & OCSP_NOCHAIN)
 105                         X509_STORE_CTX_init(&ctx, st, signer, NULL);
 106                 else
 107                         X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
 108
 109                 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 110                 ret = X509_verify_cert(&ctx);
 111                 chain = X509_STORE_CTX_get1_chain(&ctx);
 112                 X509_STORE_CTX_cleanup(&ctx);
 113                 if (ret <= 0)
 114                         {
 115                         i = X509_STORE_CTX_get_error(&ctx);
 116                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 117                         ERR_add_error_data(2, "Verify error:",
 118                                         X509_verify_cert_error_string(i));
 119                         goto end;
 120                         }
 121                 if(flags & OCSP_NOCHECKS)
 122                         {
 123                         ret = 1;
 124                         goto end;
 125                         }
 126                 /* At this point we have a valid certificate chain
 127                  * need to verify it against the OCSP issuer criteria.
 128                  */
 129                 ret = ocsp_check_issuer(bs, chain, flags);
 130
 131                 /* If fatal error or valid match then finish */
 132                 if (ret != 0) goto end;
 133
 134                 /* Easy case: explicitly trusted. Get root CA and
 135                  * check for explicit trust
 136                  */
 137                 if(flags & OCSP_NOEXPLICIT) goto end;
 138
 139                 x = sk_X509_value(chain, sk_X509_num(chain) - 1);
 140                 if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
 141                         {
 142                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
 143                         goto end;
 144                         }
 145                 ret = 1;
 146                 }
 147
 148
 149
 150         end:
 151         if(chain) sk_X509_pop_free(chain, X509_free);
 152         return ret;
 153         }
 154
 155
 156 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
 157                                 X509_STORE *st, unsigned long flags)
 158         {
 159         X509 *signer;
 160         OCSP_RESPID *rid = bs->tbsResponseData->responderId;
 161         if ((signer = ocsp_find_signer_sk(certs, rid)))
 162                 {
 163                 *psigner = signer;
 164                 return 2;
 165                 }
 166         if(!(flags & OCSP_NOINTERN) &&
 167             (signer = ocsp_find_signer_sk(bs->certs, rid)))
 168                 {
 169                 *psigner = signer;
 170                 return 1;
 171                 }
 172         /* Maybe lookup from store if by subject name */
 173
 174         *psigner = NULL;
 175         return 0;
 176         }
 177
 178
 179 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
 180         {
 181         int i;
 182         unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
 183         X509 *x;
 184
 185         /* Easy if lookup by name */
 186         if (id->type == V_OCSP_RESPID_NAME)
 187                 return X509_find_by_subject(certs, id->value.byName);
 188
 189         /* Lookup by key hash */
 190
 191         /* If key hash isn't SHA1 length then forget it */
 192         if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
 193         keyhash = id->value.byKey->data;
 194         /* Calculate hash of each key and compare */
 195         for (i = 0; i < sk_X509_num(certs); i++)
 196                 {
 197                 x = sk_X509_value(certs, i);
 198                 X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
 199                 if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
 200                         return x;
 201                 }
 202         return NULL;
 203         }
 204
 205
 206 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
 207         {
 208         STACK_OF(OCSP_SINGLERESP) *sresp;
 209         X509 *signer, *sca;
 210         OCSP_CERTID *caid = NULL;
 211         int i;
 212         sresp = bs->tbsResponseData->responses;
 213
 214         if (sk_X509_num(chain) <= 0)
 215                 {
 216                 OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
 217                 return -1;
 218                 }
 219
 220         /* See if the issuer IDs match. */
 221         i = ocsp_check_ids(sresp, &caid);
 222
 223         /* If ID mismatch or other error then return */
 224         if (i <= 0) return i;
 225
 226         signer = sk_X509_value(chain, 0);
 227         /* Check to see if OCSP responder CA matches request CA */
 228         if (sk_X509_num(chain) > 1)
 229                 {
 230                 sca = sk_X509_value(chain, 1);
 231                 i = ocsp_match_issuerid(sca, caid, sresp);
 232                 if (i < 0) return i;
 233                 if (i)
 234                         {
 235                         /* We have a match, if extensions OK then success */
 236                         if (ocsp_check_delegated(signer, flags)) return 1;
 237                         return 0;
 238                         }
 239                 }
 240
 241         /* Otherwise check if OCSP request signed directly by request CA */
 242         return ocsp_match_issuerid(signer, caid, sresp);
 243         }
 244
 245
 246 /* Check the issuer certificate IDs for equality. If there is a mismatch with the same
 247  * algorithm then there's no point trying to match any certificates against the issuer.
 248  * If the issuer IDs all match then we just need to check equality against one of them.
 249  */
 250
 251 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
 252         {
 253         OCSP_CERTID *tmpid, *cid;
 254         int i, idcount;
 255
 256         idcount = sk_OCSP_SINGLERESP_num(sresp);
 257         if (idcount <= 0)
 258                 {
 259                 OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
 260                 return -1;
 261                 }
 262
 263         cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 264
 265         *ret = NULL;
 266
 267         for (i = 1; i < idcount; i++)
 268                 {
 269                 tmpid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 270                 /* Check to see if IDs match */
 271                 if (OCSP_id_issuer_cmp(cid, tmpid))
 272                         {
 273                         /* If algoritm mismatch let caller deal with it */
 274                         if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
 275                                         cid->hashAlgorithm->algorithm))
 276                                         return 2;
 277                         /* Else mismatch */
 278                         return 0;
 279                         }
 280                 }
 281
 282         /* All IDs match: only need to check one ID */
 283         *ret = cid;
 284         return 1;
 285         }
 286
 287
 288 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
 289                         STACK_OF(OCSP_SINGLERESP) *sresp)
 290         {
 291         /* If only one ID to match then do it */
 292         if(cid)
 293                 {
 294                 const EVP_MD *dgst;
 295                 X509_NAME *iname;
 296                 int mdlen;
 297                 unsigned char md[EVP_MAX_MD_SIZE];
 298                 if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
 299                         {
 300                         OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
 301                         return -1;
 302                         }
 303
 304                 mdlen = EVP_MD_size(dgst);
 305                 if ((cid->issuerNameHash->length != mdlen) ||
 306                    (cid->issuerKeyHash->length != mdlen))
 307                         return 0;
 308                 iname = X509_get_subject_name(cert);
 309                 if (!X509_NAME_digest(iname, dgst, md, NULL))
 310                         return -1;
 311                 if (memcmp(md, cid->issuerNameHash->data, mdlen))
 312                         return 0;
 313                 X509_pubkey_digest(cert, EVP_sha1(), md, NULL);
 314                 if (memcmp(md, cid->issuerKeyHash->data, mdlen))
 315                         return 0;
 316
 317                 return 1;
 318
 319                 }
 320         else
 321                 {
 322                 /* We have to match the whole lot */
 323                 int i, ret;
 324                 OCSP_CERTID *tmpid;
 325                 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
 326                         {
 327                         tmpid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 328                         ret = ocsp_match_issuerid(cert, tmpid, NULL);
 329                         if (ret <= 0) return ret;
 330                         }
 331                 return 1;
 332                 }
 333
 334         }
 335
 336 static int ocsp_check_delegated(X509 *x, int flags)
 337         {
 338         X509_check_purpose(x, -1, 0);
 339         if ((x->ex_flags & EXFLAG_XKUSAGE) &&
 340             (x->ex_xkusage & XKU_OCSP_SIGN))
 341                 return 1;
 342         OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
 343         return 0;
 344         }
 345
 346 /* Verify an OCSP request. This is fortunately much easier than OCSP
 347  * response verify. Just find the signers certificate and verify it
 348  * against a given trust value.
 349  */
 350
 351 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags)
 352         {
 353         X509 *signer;
 354         X509_NAME *nm;
 355         GENERAL_NAME *gen;
 356         int ret;
 357         X509_STORE_CTX ctx;
 358         if (!req->optionalSignature)
 359                 {
 360                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
 361                 return 0;
 362                 }
 363         gen = req->tbsRequest->requestorName;
 364         if (gen->type != GEN_DIRNAME)
 365                 {
 366                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
 367                 return 0;
 368                 }
 369         nm = gen->d.directoryName;
 370         ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
 371         if (ret <= 0)
 372                 {
 373                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 374                 return 0;
 375                 }
 376         if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 377                 flags |= OCSP_NOVERIFY;
 378         if (!(flags & OCSP_NOSIGS))
 379                 {
 380                 EVP_PKEY *skey;
 381                 skey = X509_get_pubkey(signer);
 382                 ret = OCSP_REQUEST_verify(req, skey);
 383                 EVP_PKEY_free(skey);
 384                 if(ret <= 0)
 385                         {
 386                         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 387                         return 0;
 388                         }
 389                 }
 390         if (!(flags & OCSP_NOVERIFY))
 391                 {
 392                 if(flags & OCSP_NOCHAIN)
 393                         X509_STORE_CTX_init(&ctx, store, signer, NULL);
 394                 else
 395                         X509_STORE_CTX_init(&ctx, store, signer, req->optionalSignature->certs);
 396
 397                 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 398                 X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
 399                 ret = X509_verify_cert(&ctx);
 400                 X509_STORE_CTX_cleanup(&ctx);
 401                 if (ret <= 0)
 402                         {
 403                         ret = X509_STORE_CTX_get_error(&ctx);
 404                         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 405                         ERR_add_error_data(2, "Verify error:",
 406                                         X509_verify_cert_error_string(ret));
 407                         return 0;
 408                         }
 409                 }
 410         return 1;
 411         }
 412
 413 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
 414                                 X509_STORE *st, unsigned long flags)
 415         {
 416         X509 *signer;
 417         if(!(flags & OCSP_NOINTERN))
 418                 {
 419                 signer = X509_find_by_subject(req->optionalSignature->certs, nm);
 420                 *psigner = signer;
 421                 return 1;
 422                 }
 423
 424         signer = X509_find_by_subject(certs, nm);
 425         if (signer)
 426                 {
 427                 *psigner = signer;
 428                 return 2;
 429                 }
 430         return 0;
 431         }