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 63static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs, 64 X509_STORE *st, unsigned long flags); 65static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id); 66static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags); 67static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret); 68static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp); 69static int ocsp_check_delegated(X509 *x, int flags); 70static 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 75int 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 166static 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 189static 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 216static 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 261static 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 298static 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 ((cid->issuerNameHash->length != mdlen) || 316 (cid->issuerKeyHash->length != mdlen)) 317 return 0; 318 iname = X509_get_subject_name(cert); 319 if (!X509_NAME_digest(iname, dgst, md, NULL)) 320 return -1; 321 if (memcmp(md, cid->issuerNameHash->data, mdlen)) 322 return 0; 323 X509_pubkey_digest(cert, EVP_sha1(), md, NULL); 324 if (memcmp(md, cid->issuerKeyHash->data, mdlen)) 325 return 0; 326 327 return 1; 328 329 } 330 else 331 { 332 /* We have to match the whole lot */ 333 int i, ret; 334 OCSP_CERTID *tmpid; 335 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) 336 { 337 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId; 338 ret = ocsp_match_issuerid(cert, tmpid, NULL); 339 if (ret <= 0) return ret; 340 } 341 return 1; 342 } 343 344 } 345 346static int ocsp_check_delegated(X509 *x, int flags) 347 { 348 X509_check_purpose(x, -1, 0); 349 if ((x->ex_flags & EXFLAG_XKUSAGE) && 350 (x->ex_xkusage & XKU_OCSP_SIGN)) 351 return 1; 352 OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE); 353 return 0; 354 } 355 356/* Verify an OCSP request. This is fortunately much easier than OCSP 357 * response verify. Just find the signers certificate and verify it 358 * against a given trust value. 359 */ 360 361int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags) 362 { 363 X509 *signer; 364 X509_NAME *nm; 365 GENERAL_NAME *gen; 366 int ret; 367 X509_STORE_CTX ctx; 368 if (!req->optionalSignature) 369 { 370 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED); 371 return 0; 372 } 373 gen = req->tbsRequest->requestorName; 374 if (!gen || gen->type != GEN_DIRNAME) 375 { 376 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE); 377 return 0; 378 } 379 nm = gen->d.directoryName; 380 ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags); 381 if (ret <= 0) 382 { 383 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND); 384 return 0; 385 } 386 if ((ret == 2) && (flags & OCSP_TRUSTOTHER)) 387 flags |= OCSP_NOVERIFY; 388 if (!(flags & OCSP_NOSIGS)) 389 { 390 EVP_PKEY *skey; 391 skey = X509_get_pubkey(signer); 392 ret = OCSP_REQUEST_verify(req, skey); 393 EVP_PKEY_free(skey); 394 if(ret <= 0) 395 { 396 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE); 397 return 0; 398 } 399 } 400 if (!(flags & OCSP_NOVERIFY)) 401 { 402 int init_res; 403 if(flags & OCSP_NOCHAIN) 404 init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL); 405 else 406 init_res = X509_STORE_CTX_init(&ctx, store, signer, 407 req->optionalSignature->certs); 408 if(!init_res) 409 { 410 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB); 411 return 0; 412 } 413 414 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER); 415 X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST); 416 ret = X509_verify_cert(&ctx); 417 X509_STORE_CTX_cleanup(&ctx); 418 if (ret <= 0) 419 { 420 ret = X509_STORE_CTX_get_error(&ctx); 421 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR); 422 ERR_add_error_data(2, "Verify error:", 423 X509_verify_cert_error_string(ret)); 424 return 0; 425 } 426 } 427 return 1; 428 } 429 430static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs, 431 X509_STORE *st, unsigned long flags) 432 { 433 X509 *signer; 434 if(!(flags & OCSP_NOINTERN)) 435 { 436 signer = X509_find_by_subject(req->optionalSignature->certs, nm); 437 *psigner = signer; 438 return 1; 439 } 440 441 signer = X509_find_by_subject(certs, nm); 442 if (signer) 443 { 444 *psigner = signer; 445 return 2; 446 } 447 return 0; 448 } 449