1 /* ocsp_vfy.c */ 2 /* Written by Dr Stephen N Henson (steve (at) 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 (at) 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 (at) cryptsoft.com). This product includes software written by Tim 55 * Hudson (tjh (at) 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 int init_res; 105 if(flags & OCSP_NOCHAIN) 106 init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL); 107 else 108 init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs); 109 if(!init_res) 110 { 111 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB); 112 goto end; 113 } 114 115 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER); 116 ret = X509_verify_cert(&ctx); 117 chain = X509_STORE_CTX_get1_chain(&ctx); 118 X509_STORE_CTX_cleanup(&ctx); 119 if (ret <= 0) 120 { 121 i = X509_STORE_CTX_get_error(&ctx); 122 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR); 123 ERR_add_error_data(2, "Verify error:", 124 X509_verify_cert_error_string(i)); 125 goto end; 126 } 127 if(flags & OCSP_NOCHECKS) 128 { 129 ret = 1; 130 goto end; 131 } 132 /* At this point we have a valid certificate chain 133 * need to verify it against the OCSP issuer criteria. 134 */ 135 ret = ocsp_check_issuer(bs, chain, flags); 136 137 /* If fatal error or valid match then finish */ 138 if (ret != 0) goto end; 139 140 /* Easy case: explicitly trusted. Get root CA and 141 * check for explicit trust 142 */ 143 if(flags & OCSP_NOEXPLICIT) goto end; 144 145 x = sk_X509_value(chain, sk_X509_num(chain) - 1); 146 if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) 147 { 148 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED); 149 goto end; 150 } 151 ret = 1; 152 } 153 154 155 156 end: 157 if(chain) sk_X509_pop_free(chain, X509_free); 158 return ret; 159 } 160 161 162 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs, 163 X509_STORE *st, unsigned long flags) 164 { 165 X509 *signer; 166 OCSP_RESPID *rid = bs->tbsResponseData->responderId; 167 if ((signer = ocsp_find_signer_sk(certs, rid))) 168 { 169 *psigner = signer; 170 return 2; 171 } 172 if(!(flags & OCSP_NOINTERN) && 173 (signer = ocsp_find_signer_sk(bs->certs, rid))) 174 { 175 *psigner = signer; 176 return 1; 177 } 178 /* Maybe lookup from store if by subject name */ 179 180 *psigner = NULL; 181 return 0; 182 } 183 184 185 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id) 186 { 187 int i; 188 unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash; 189 X509 *x; 190 191 /* Easy if lookup by name */ 192 if (id->type == V_OCSP_RESPID_NAME) 193 return X509_find_by_subject(certs, id->value.byName); 194 195 /* Lookup by key hash */ 196 197 /* If key hash isn't SHA1 length then forget it */ 198 if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL; 199 keyhash = id->value.byKey->data; 200 /* Calculate hash of each key and compare */ 201 for (i = 0; i < sk_X509_num(certs); i++) 202 { 203 x = sk_X509_value(certs, i); 204 X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL); 205 if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH)) 206 return x; 207 } 208 return NULL; 209 } 210 211 212 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags) 213 { 214 STACK_OF(OCSP_SINGLERESP) *sresp; 215 X509 *signer, *sca; 216 OCSP_CERTID *caid = NULL; 217 int i; 218 sresp = bs->tbsResponseData->responses; 219 220 if (sk_X509_num(chain) <= 0) 221 { 222 OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN); 223 return -1; 224 } 225 226 /* See if the issuer IDs match. */ 227 i = ocsp_check_ids(sresp, &caid); 228 229 /* If ID mismatch or other error then return */ 230 if (i <= 0) return i; 231 232 signer = sk_X509_value(chain, 0); 233 /* Check to see if OCSP responder CA matches request CA */ 234 if (sk_X509_num(chain) > 1) 235 { 236 sca = sk_X509_value(chain, 1); 237 i = ocsp_match_issuerid(sca, caid, sresp); 238 if (i < 0) return i; 239 if (i) 240 { 241 /* We have a match, if extensions OK then success */ 242 if (ocsp_check_delegated(signer, flags)) return 1; 243 return 0; 244 } 245 } 246 247 /* Otherwise check if OCSP request signed directly by request CA */ 248 return ocsp_match_issuerid(signer, caid, sresp); 249 } 250 251 252 /* Check the issuer certificate IDs for equality. If there is a mismatch with the same 253 * algorithm then there's no point trying to match any certificates against the issuer. 254 * If the issuer IDs all match then we just need to check equality against one of them. 255 */ 256 257 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret) 258 { 259 OCSP_CERTID *tmpid, *cid; 260 int i, idcount; 261 262 idcount = sk_OCSP_SINGLERESP_num(sresp); 263 if (idcount <= 0) 264 { 265 OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA); 266 return -1; 267 } 268 269 cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId; 270 271 *ret = NULL; 272 273 for (i = 1; i < idcount; i++) 274 { 275 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId; 276 /* Check to see if IDs match */ 277 if (OCSP_id_issuer_cmp(cid, tmpid)) 278 { 279 /* If algoritm mismatch let caller deal with it */ 280 if (OBJ_cmp(tmpid->hashAlgorithm->algorithm, 281 cid->hashAlgorithm->algorithm)) 282 return 2; 283 /* Else mismatch */ 284 return 0; 285 } 286 } 287 288 /* All IDs match: only need to check one ID */ 289 *ret = cid; 290 return 1; 291 } 292 293 294 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, 295 STACK_OF(OCSP_SINGLERESP) *sresp) 296 { 297 /* If only one ID to match then do it */ 298 if(cid) 299 { 300 const EVP_MD *dgst; 301 X509_NAME *iname; 302 int mdlen; 303 unsigned char md[EVP_MAX_MD_SIZE]; 304 if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm))) 305 { 306 OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST); 307 return -1; 308 } 309 310 mdlen = EVP_MD_size(dgst); 311 if ((cid->issuerNameHash->length != mdlen) || 312 (cid->issuerKeyHash->length != mdlen)) 313 return 0; 314 iname = X509_get_subject_name(cert); 315 if (!X509_NAME_digest(iname, dgst, md, NULL)) 316 return -1; 317 if (memcmp(md, cid->issuerNameHash->data, mdlen)) 318 return 0; 319 X509_pubkey_digest(cert, EVP_sha1(), md, NULL); 320 if (memcmp(md, cid->issuerKeyHash->data, mdlen)) 321 return 0; 322 323 return 1; 324 325 } 326 else 327 { 328 /* We have to match the whole lot */ 329 int i, ret; 330 OCSP_CERTID *tmpid; 331 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) 332 { 333 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId; 334 ret = ocsp_match_issuerid(cert, tmpid, NULL); 335 if (ret <= 0) return ret; 336 } 337 return 1; 338 } 339 340 } 341 342 static int ocsp_check_delegated(X509 *x, int flags) 343 { 344 X509_check_purpose(x, -1, 0); 345 if ((x->ex_flags & EXFLAG_XKUSAGE) && 346 (x->ex_xkusage & XKU_OCSP_SIGN)) 347 return 1; 348 OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE); 349 return 0; 350 } 351 352 /* Verify an OCSP request. This is fortunately much easier than OCSP 353 * response verify. Just find the signers certificate and verify it 354 * against a given trust value. 355 */ 356 357 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags) 358 { 359 X509 *signer; 360 X509_NAME *nm; 361 GENERAL_NAME *gen; 362 int ret; 363 X509_STORE_CTX ctx; 364 if (!req->optionalSignature) 365 { 366 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED); 367 return 0; 368 } 369 gen = req->tbsRequest->requestorName; 370 if (!gen || gen->type != GEN_DIRNAME) 371 { 372 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE); 373 return 0; 374 } 375 nm = gen->d.directoryName; 376 ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags); 377 if (ret <= 0) 378 { 379 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND); 380 return 0; 381 } 382 if ((ret == 2) && (flags & OCSP_TRUSTOTHER)) 383 flags |= OCSP_NOVERIFY; 384 if (!(flags & OCSP_NOSIGS)) 385 { 386 EVP_PKEY *skey; 387 skey = X509_get_pubkey(signer); 388 ret = OCSP_REQUEST_verify(req, skey); 389 EVP_PKEY_free(skey); 390 if(ret <= 0) 391 { 392 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE); 393 return 0; 394 } 395 } 396 if (!(flags & OCSP_NOVERIFY)) 397 { 398 int init_res; 399 if(flags & OCSP_NOCHAIN) 400 init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL); 401 else 402 init_res = X509_STORE_CTX_init(&ctx, store, signer, 403 req->optionalSignature->certs); 404 if(!init_res) 405 { 406 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB); 407 return 0; 408 } 409 410 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER); 411 X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST); 412 ret = X509_verify_cert(&ctx); 413 X509_STORE_CTX_cleanup(&ctx); 414 if (ret <= 0) 415 { 416 ret = X509_STORE_CTX_get_error(&ctx); 417 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR); 418 ERR_add_error_data(2, "Verify error:", 419 X509_verify_cert_error_string(ret)); 420 return 0; 421 } 422 } 423 return 1; 424 } 425 426 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs, 427 X509_STORE *st, unsigned long flags) 428 { 429 X509 *signer; 430 if(!(flags & OCSP_NOINTERN)) 431 { 432 signer = X509_find_by_subject(req->optionalSignature->certs, nm); 433 *psigner = signer; 434 return 1; 435 } 436 437 signer = X509_find_by_subject(certs, nm); 438 if (signer) 439 { 440 *psigner = signer; 441 return 2; 442 } 443 return 0; 444 } 445
