1 /* ocsp_vfy.c */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project 2000.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2000-2004 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                 if (skey)
  95                         {
  96                         ret = OCSP_BASICRESP_verify(bs, skey, 0);
  97                         EVP_PKEY_free(skey);
  98                         }
  99                 if(!skey || ret <= 0)
 100                         {
 101                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 102                         goto end;
 103                         }
 104                 }
 105         if (!(flags & OCSP_NOVERIFY))
 106                 {
 107                 int init_res;
 108                 if(flags & OCSP_NOCHAIN)
 109                         init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL);
 110                 else
 111                         init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
 112                 if(!init_res)
 113                         {
 114                         ret = -1;
 115                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
 116                         goto end;
 117                         }
 118 
 119                 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 120                 ret = X509_verify_cert(&ctx);
 121                 chain = X509_STORE_CTX_get1_chain(&ctx);
 122                 X509_STORE_CTX_cleanup(&ctx);
 123                 if (ret <= 0)
 124                         {
 125                         i = X509_STORE_CTX_get_error(&ctx);
 126                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 127                         ERR_add_error_data(2, "Verify error:",
 128                                         X509_verify_cert_error_string(i));
 129                         goto end;
 130                         }
 131                 if(flags & OCSP_NOCHECKS)
 132                         {
 133                         ret = 1;
 134                         goto end;
 135                         }
 136                 /* At this point we have a valid certificate chain
 137                  * need to verify it against the OCSP issuer criteria.
 138                  */
 139                 ret = ocsp_check_issuer(bs, chain, flags);
 140 
 141                 /* If fatal error or valid match then finish */
 142                 if (ret != 0) goto end;
 143 
 144                 /* Easy case: explicitly trusted. Get root CA and
 145                  * check for explicit trust
 146                  */
 147                 if(flags & OCSP_NOEXPLICIT) goto end;
 148 
 149                 x = sk_X509_value(chain, sk_X509_num(chain) - 1);
 150                 if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
 151                         {
 152                         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
 153                         goto end;
 154                         }
 155                 ret = 1;
 156                 }
 157 
 158 
 159 
 160         end:
 161         if(chain) sk_X509_pop_free(chain, X509_free);
 162         return ret;
 163         }
 164 
 165 
 166 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
 167                                 X509_STORE *st, unsigned long flags)
 168         {
 169         X509 *signer;
 170         OCSP_RESPID *rid = bs->tbsResponseData->responderId;
 171         if ((signer = ocsp_find_signer_sk(certs, rid)))
 172                 {
 173                 *psigner = signer;
 174                 return 2;
 175                 }
 176         if(!(flags & OCSP_NOINTERN) &&
 177             (signer = ocsp_find_signer_sk(bs->certs, rid)))
 178                 {
 179                 *psigner = signer;
 180                 return 1;
 181                 }
 182         /* Maybe lookup from store if by subject name */
 183 
 184         *psigner = NULL;
 185         return 0;
 186         }
 187 
 188 
 189 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
 190         {
 191         int i;
 192         unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
 193         X509 *x;
 194 
 195         /* Easy if lookup by name */
 196         if (id->type == V_OCSP_RESPID_NAME)
 197                 return X509_find_by_subject(certs, id->value.byName);
 198 
 199         /* Lookup by key hash */
 200 
 201         /* If key hash isn't SHA1 length then forget it */
 202         if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
 203         keyhash = id->value.byKey->data;
 204         /* Calculate hash of each key and compare */
 205         for (i = 0; i < sk_X509_num(certs); i++)
 206                 {
 207                 x = sk_X509_value(certs, i);
 208                 X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
 209                 if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
 210                         return x;
 211                 }
 212         return NULL;
 213         }
 214 
 215 
 216 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
 217         {
 218         STACK_OF(OCSP_SINGLERESP) *sresp;
 219         X509 *signer, *sca;
 220         OCSP_CERTID *caid = NULL;
 221         int i;
 222         sresp = bs->tbsResponseData->responses;
 223 
 224         if (sk_X509_num(chain) <= 0)
 225                 {
 226                 OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
 227                 return -1;
 228                 }
 229 
 230         /* See if the issuer IDs match. */
 231         i = ocsp_check_ids(sresp, &caid);
 232 
 233         /* If ID mismatch or other error then return */
 234         if (i <= 0) return i;
 235 
 236         signer = sk_X509_value(chain, 0);
 237         /* Check to see if OCSP responder CA matches request CA */
 238         if (sk_X509_num(chain) > 1)
 239                 {
 240                 sca = sk_X509_value(chain, 1);
 241                 i = ocsp_match_issuerid(sca, caid, sresp);
 242                 if (i < 0) return i;
 243                 if (i)
 244                         {
 245                         /* We have a match, if extensions OK then success */
 246                         if (ocsp_check_delegated(signer, flags)) return 1;
 247                         return 0;
 248                         }
 249                 }
 250 
 251         /* Otherwise check if OCSP request signed directly by request CA */
 252         return ocsp_match_issuerid(signer, caid, sresp);
 253         }
 254 
 255 
 256 /* Check the issuer certificate IDs for equality. If there is a mismatch with the same
 257  * algorithm then there's no point trying to match any certificates against the issuer.
 258  * If the issuer IDs all match then we just need to check equality against one of them.
 259  */
 260 
 261 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
 262         {
 263         OCSP_CERTID *tmpid, *cid;
 264         int i, idcount;
 265 
 266         idcount = sk_OCSP_SINGLERESP_num(sresp);
 267         if (idcount <= 0)
 268                 {
 269                 OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
 270                 return -1;
 271                 }
 272 
 273         cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 274 
 275         *ret = NULL;
 276 
 277         for (i = 1; i < idcount; i++)
 278                 {
 279                 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 280                 /* Check to see if IDs match */
 281                 if (OCSP_id_issuer_cmp(cid, tmpid))
 282                         {
 283                         /* If algoritm mismatch let caller deal with it */
 284                         if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
 285                                         cid->hashAlgorithm->algorithm))
 286                                         return 2;
 287                         /* Else mismatch */
 288                         return 0;
 289                         }
 290                 }
 291 
 292         /* All IDs match: only need to check one ID */
 293         *ret = cid;
 294         return 1;
 295         }
 296 
 297 
 298 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
 299                         STACK_OF(OCSP_SINGLERESP) *sresp)
 300         {
 301         /* If only one ID to match then do it */
 302         if(cid)
 303                 {
 304                 const EVP_MD *dgst;
 305                 X509_NAME *iname;
 306                 int mdlen;
 307                 unsigned char md[EVP_MAX_MD_SIZE];
 308                 if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
 309                         {
 310                         OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
 311                         return -1;
 312                         }
 313 
 314                 mdlen = EVP_MD_size(dgst);
 315                 if (mdlen < 0)
 316                     return -1;
 317                 if ((cid->issuerNameHash->length != mdlen) ||
 318                    (cid->issuerKeyHash->length != mdlen))
 319                         return 0;
 320                 iname = X509_get_subject_name(cert);
 321                 if (!X509_NAME_digest(iname, dgst, md, NULL))
 322                         return -1;
 323                 if (memcmp(md, cid->issuerNameHash->data, mdlen))
 324                         return 0;
 325                 X509_pubkey_digest(cert, dgst, md, NULL);
 326                 if (memcmp(md, cid->issuerKeyHash->data, mdlen))
 327                         return 0;
 328 
 329                 return 1;
 330 
 331                 }
 332         else
 333                 {
 334                 /* We have to match the whole lot */
 335                 int i, ret;
 336                 OCSP_CERTID *tmpid;
 337                 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
 338                         {
 339                         tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 340                         ret = ocsp_match_issuerid(cert, tmpid, NULL);
 341                         if (ret <= 0) return ret;
 342                         }
 343                 return 1;
 344                 }
 345 
 346         }
 347 
 348 static int ocsp_check_delegated(X509 *x, int flags)
 349         {
 350         X509_check_purpose(x, -1, 0);
 351         if ((x->ex_flags & EXFLAG_XKUSAGE) &&
 352             (x->ex_xkusage & XKU_OCSP_SIGN))
 353                 return 1;
 354         OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
 355         return 0;
 356         }
 357 
 358 /* Verify an OCSP request. This is fortunately much easier than OCSP
 359  * response verify. Just find the signers certificate and verify it
 360  * against a given trust value.
 361  */
 362 
 363 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags)
 364         {
 365         X509 *signer;
 366         X509_NAME *nm;
 367         GENERAL_NAME *gen;
 368         int ret;
 369         X509_STORE_CTX ctx;
 370         if (!req->optionalSignature)
 371                 {
 372                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
 373                 return 0;
 374                 }
 375         gen = req->tbsRequest->requestorName;
 376         if (!gen || gen->type != GEN_DIRNAME)
 377                 {
 378                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
 379                 return 0;
 380                 }
 381         nm = gen->d.directoryName;
 382         ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
 383         if (ret <= 0)
 384                 {
 385                 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 386                 return 0;
 387                 }
 388         if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 389                 flags |= OCSP_NOVERIFY;
 390         if (!(flags & OCSP_NOSIGS))
 391                 {
 392                 EVP_PKEY *skey;
 393                 skey = X509_get_pubkey(signer);
 394                 ret = OCSP_REQUEST_verify(req, skey);
 395                 EVP_PKEY_free(skey);
 396                 if(ret <= 0)
 397                         {
 398                         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 399                         return 0;
 400                         }
 401                 }
 402         if (!(flags & OCSP_NOVERIFY))
 403                 {
 404                 int init_res;
 405                 if(flags & OCSP_NOCHAIN)
 406                         init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
 407                 else
 408                         init_res = X509_STORE_CTX_init(&ctx, store, signer,
 409                                         req->optionalSignature->certs);
 410                 if(!init_res)
 411                         {
 412                         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB);
 413                         return 0;
 414                         }
 415 
 416                 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 417                 X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
 418                 ret = X509_verify_cert(&ctx);
 419                 X509_STORE_CTX_cleanup(&ctx);
 420                 if (ret <= 0)
 421                         {
 422                         ret = X509_STORE_CTX_get_error(&ctx);
 423                         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
 424                         ERR_add_error_data(2, "Verify error:",
 425                                         X509_verify_cert_error_string(ret));
 426                         return 0;
 427                         }
 428                 }
 429         return 1;
 430         }
 431 
 432 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
 433                                 X509_STORE *st, unsigned long flags)
 434         {
 435         X509 *signer;
 436         if(!(flags & OCSP_NOINTERN))
 437                 {
 438                 signer = X509_find_by_subject(req->optionalSignature->certs, nm);
 439                 *psigner = signer;
 440                 return 1;
 441                 }
 442 
 443         signer = X509_find_by_subject(certs, nm);
 444         if (signer)
 445                 {
 446                 *psigner = signer;
 447                 return 2;
 448                 }
 449         return 0;
 450         }