Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 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 | 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 (mdlen < 0) |
| 312 | return -1; |
| 313 | if ((cid->issuerNameHash->length != mdlen) || |
| 314 | (cid->issuerKeyHash->length != mdlen)) |
| 315 | return 0; |
| 316 | iname = X509_get_subject_name(cert); |
| 317 | if (!X509_NAME_digest(iname, dgst, md, NULL)) |
| 318 | return -1; |
| 319 | if (memcmp(md, cid->issuerNameHash->data, mdlen)) |
| 320 | return 0; |
| 321 | X509_pubkey_digest(cert, dgst, md, NULL); |
| 322 | if (memcmp(md, cid->issuerKeyHash->data, mdlen)) |
| 323 | return 0; |
| 324 | |
| 325 | return 1; |
| 326 | |
| 327 | } |
| 328 | else |
| 329 | { |
| 330 | /* We have to match the whole lot */ |
| 331 | int i, ret; |
| 332 | OCSP_CERTID *tmpid; |
| 333 | for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) |
| 334 | { |
| 335 | tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId; |
| 336 | ret = ocsp_match_issuerid(cert, tmpid, NULL); |
| 337 | if (ret <= 0) return ret; |
| 338 | } |
| 339 | return 1; |
| 340 | } |
| 341 | |
| 342 | } |
| 343 | |
| 344 | static int ocsp_check_delegated(X509 *x, int flags) |
| 345 | { |
| 346 | X509_check_purpose(x, -1, 0); |
| 347 | if ((x->ex_flags & EXFLAG_XKUSAGE) && |
| 348 | (x->ex_xkusage & XKU_OCSP_SIGN)) |
| 349 | return 1; |
| 350 | OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE); |
| 351 | return 0; |
| 352 | } |
| 353 | |
| 354 | /* Verify an OCSP request. This is fortunately much easier than OCSP |
| 355 | * response verify. Just find the signers certificate and verify it |
| 356 | * against a given trust value. |
| 357 | */ |
| 358 | |
| 359 | int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags) |
| 360 | { |
| 361 | X509 *signer; |
| 362 | X509_NAME *nm; |
| 363 | GENERAL_NAME *gen; |
| 364 | int ret; |
| 365 | X509_STORE_CTX ctx; |
| 366 | if (!req->optionalSignature) |
| 367 | { |
| 368 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED); |
| 369 | return 0; |
| 370 | } |
| 371 | gen = req->tbsRequest->requestorName; |
| 372 | if (!gen || gen->type != GEN_DIRNAME) |
| 373 | { |
| 374 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE); |
| 375 | return 0; |
| 376 | } |
| 377 | nm = gen->d.directoryName; |
| 378 | ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags); |
| 379 | if (ret <= 0) |
| 380 | { |
| 381 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND); |
| 382 | return 0; |
| 383 | } |
| 384 | if ((ret == 2) && (flags & OCSP_TRUSTOTHER)) |
| 385 | flags |= OCSP_NOVERIFY; |
| 386 | if (!(flags & OCSP_NOSIGS)) |
| 387 | { |
| 388 | EVP_PKEY *skey; |
| 389 | skey = X509_get_pubkey(signer); |
| 390 | ret = OCSP_REQUEST_verify(req, skey); |
| 391 | EVP_PKEY_free(skey); |
| 392 | if(ret <= 0) |
| 393 | { |
| 394 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE); |
| 395 | return 0; |
| 396 | } |
| 397 | } |
| 398 | if (!(flags & OCSP_NOVERIFY)) |
| 399 | { |
| 400 | int init_res; |
| 401 | if(flags & OCSP_NOCHAIN) |
| 402 | init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL); |
| 403 | else |
| 404 | init_res = X509_STORE_CTX_init(&ctx, store, signer, |
| 405 | req->optionalSignature->certs); |
| 406 | if(!init_res) |
| 407 | { |
| 408 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB); |
| 409 | return 0; |
| 410 | } |
| 411 | |
| 412 | X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER); |
| 413 | X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST); |
| 414 | ret = X509_verify_cert(&ctx); |
| 415 | X509_STORE_CTX_cleanup(&ctx); |
| 416 | if (ret <= 0) |
| 417 | { |
| 418 | ret = X509_STORE_CTX_get_error(&ctx); |
| 419 | OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR); |
| 420 | ERR_add_error_data(2, "Verify error:", |
| 421 | X509_verify_cert_error_string(ret)); |
| 422 | return 0; |
| 423 | } |
| 424 | } |
| 425 | return 1; |
| 426 | } |
| 427 | |
| 428 | static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs, |
| 429 | X509_STORE *st, unsigned long flags) |
| 430 | { |
| 431 | X509 *signer; |
| 432 | if(!(flags & OCSP_NOINTERN)) |
| 433 | { |
| 434 | signer = X509_find_by_subject(req->optionalSignature->certs, nm); |
| 435 | *psigner = signer; |
| 436 | return 1; |
| 437 | } |
| 438 | |
| 439 | signer = X509_find_by_subject(certs, nm); |
| 440 | if (signer) |
| 441 | { |
| 442 | *psigner = signer; |
| 443 | return 2; |
| 444 | } |
| 445 | return 0; |
| 446 | } |