crypto/ocsp/ocsp_vfy.c

   1 /*
   2  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   3  * 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 "ocsp_lcl.h"
  61 #include <openssl/err.h>
  62 #include <string.h>
  63
  64 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
  65                             STACK_OF(X509) *certs, X509_STORE *st,
  66                             unsigned long flags);
  67 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
  68 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain,
  69                              unsigned long flags);
  70 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp,
  71                           OCSP_CERTID **ret);
  72 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
  73                                STACK_OF(OCSP_SINGLERESP) *sresp);
  74 static int ocsp_check_delegated(X509 *x, int flags);
  75 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
  76                                 X509_NAME *nm, STACK_OF(X509) *certs,
  77                                 X509_STORE *st, unsigned long flags);
  78
  79 /* Verify a basic response message */
  80
  81 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
  82                       X509_STORE *st, unsigned long flags)
  83 {
  84     X509 *signer, *x;
  85     STACK_OF(X509) *chain = NULL;
  86     STACK_OF(X509) *untrusted = NULL;
  87     X509_STORE_CTX ctx;
  88     int i, ret = 0;
  89     ret = ocsp_find_signer(&signer, bs, certs, st, flags);
  90     if (!ret) {
  91         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
  92                 OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
  93         goto end;
  94     }
  95     if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
  96         flags |= OCSP_NOVERIFY;
  97     if (!(flags & OCSP_NOSIGS)) {
  98         EVP_PKEY *skey;
  99         skey = X509_get0_pubkey(signer);
 100         if (skey)
 101             ret = OCSP_BASICRESP_verify(bs, skey, 0);
 102         if (!skey || ret <= 0) {
 103             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 104             goto end;
 105         }
 106     }
 107     if (!(flags & OCSP_NOVERIFY)) {
 108         int init_res;
 109         if (flags & OCSP_NOCHAIN) {
 110             untrusted = NULL;
 111         } else if (bs->certs && certs) {
 112             untrusted = sk_X509_dup(bs->certs);
 113             for (i = 0; i < sk_X509_num(certs); i++) {
 114                 if (!sk_X509_push(untrusted, sk_X509_value(certs, i))) {
 115                     OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
 116                     goto end;
 117                 }
 118             }
 119         } else {
 120             untrusted = bs->certs;
 121         }
 122         init_res = X509_STORE_CTX_init(&ctx, st, signer, untrusted);
 123         if (!init_res) {
 124             ret = -1;
 125             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_X509_LIB);
 126             goto end;
 127         }
 128
 129         X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 130         ret = X509_verify_cert(&ctx);
 131         chain = X509_STORE_CTX_get1_chain(&ctx);
 132         X509_STORE_CTX_cleanup(&ctx);
 133         if (ret <= 0) {
 134             i = X509_STORE_CTX_get_error(&ctx);
 135             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
 136                     OCSP_R_CERTIFICATE_VERIFY_ERROR);
 137             ERR_add_error_data(2, "Verify error:",
 138                                X509_verify_cert_error_string(i));
 139             goto end;
 140         }
 141         if (flags & OCSP_NOCHECKS) {
 142             ret = 1;
 143             goto end;
 144         }
 145         /*
 146          * At this point we have a valid certificate chain need to verify it
 147          * against the OCSP issuer criteria.
 148          */
 149         ret = ocsp_check_issuer(bs, chain, flags);
 150
 151         /* If fatal error or valid match then finish */
 152         if (ret != 0)
 153             goto end;
 154
 155         /*
 156          * Easy case: explicitly trusted. Get root CA and check for explicit
 157          * trust
 158          */
 159         if (flags & OCSP_NOEXPLICIT)
 160             goto end;
 161
 162         x = sk_X509_value(chain, sk_X509_num(chain) - 1);
 163         if (X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) {
 164             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_ROOT_CA_NOT_TRUSTED);
 165             goto end;
 166         }
 167         ret = 1;
 168     }
 169
 170  end:
 171     sk_X509_pop_free(chain, X509_free);
 172     if (bs->certs && certs)
 173         sk_X509_free(untrusted);
 174     return ret;
 175 }
 176
 177 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
 178                             STACK_OF(X509) *certs, X509_STORE *st,
 179                             unsigned long flags)
 180 {
 181     X509 *signer;
 182     OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
 183     if ((signer = ocsp_find_signer_sk(certs, rid))) {
 184         *psigner = signer;
 185         return 2;
 186     }
 187     if (!(flags & OCSP_NOINTERN) &&
 188         (signer = ocsp_find_signer_sk(bs->certs, rid))) {
 189         *psigner = signer;
 190         return 1;
 191     }
 192     /* Maybe lookup from store if by subject name */
 193
 194     *psigner = NULL;
 195     return 0;
 196 }
 197
 198 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
 199 {
 200     int i;
 201     unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
 202     X509 *x;
 203
 204     /* Easy if lookup by name */
 205     if (id->type == V_OCSP_RESPID_NAME)
 206         return X509_find_by_subject(certs, id->value.byName);
 207
 208     /* Lookup by key hash */
 209
 210     /* If key hash isn't SHA1 length then forget it */
 211     if (id->value.byKey->length != SHA_DIGEST_LENGTH)
 212         return NULL;
 213     keyhash = id->value.byKey->data;
 214     /* Calculate hash of each key and compare */
 215     for (i = 0; i < sk_X509_num(certs); i++) {
 216         x = sk_X509_value(certs, i);
 217         X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
 218         if (!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
 219             return x;
 220     }
 221     return NULL;
 222 }
 223
 224 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain,
 225                              unsigned long flags)
 226 {
 227     STACK_OF(OCSP_SINGLERESP) *sresp;
 228     X509 *signer, *sca;
 229     OCSP_CERTID *caid = NULL;
 230     int i;
 231     sresp = bs->tbsResponseData.responses;
 232
 233     if (sk_X509_num(chain) <= 0) {
 234         OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
 235         return -1;
 236     }
 237
 238     /* See if the issuer IDs match. */
 239     i = ocsp_check_ids(sresp, &caid);
 240
 241     /* If ID mismatch or other error then return */
 242     if (i <= 0)
 243         return i;
 244
 245     signer = sk_X509_value(chain, 0);
 246     /* Check to see if OCSP responder CA matches request CA */
 247     if (sk_X509_num(chain) > 1) {
 248         sca = sk_X509_value(chain, 1);
 249         i = ocsp_match_issuerid(sca, caid, sresp);
 250         if (i < 0)
 251             return i;
 252         if (i) {
 253             /* We have a match, if extensions OK then success */
 254             if (ocsp_check_delegated(signer, flags))
 255                 return 1;
 256             return 0;
 257         }
 258     }
 259
 260     /* Otherwise check if OCSP request signed directly by request CA */
 261     return ocsp_match_issuerid(signer, caid, sresp);
 262 }
 263
 264 /*
 265  * Check the issuer certificate IDs for equality. If there is a mismatch with
 266  * the same algorithm then there's no point trying to match any certificates
 267  * against the issuer. If the issuer IDs all match then we just need to check
 268  * equality against one of them.
 269  */
 270
 271 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
 272 {
 273     OCSP_CERTID *tmpid, *cid;
 274     int i, idcount;
 275
 276     idcount = sk_OCSP_SINGLERESP_num(sresp);
 277     if (idcount <= 0) {
 278         OCSPerr(OCSP_F_OCSP_CHECK_IDS,
 279                 OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
 280         return -1;
 281     }
 282
 283     cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 284
 285     *ret = NULL;
 286
 287     for (i = 1; i < idcount; i++) {
 288         tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 289         /* Check to see if IDs match */
 290         if (OCSP_id_issuer_cmp(cid, tmpid)) {
 291             /* If algoritm mismatch let caller deal with it */
 292             if (OBJ_cmp(tmpid->hashAlgorithm.algorithm,
 293                         cid->hashAlgorithm.algorithm))
 294                 return 2;
 295             /* Else mismatch */
 296             return 0;
 297         }
 298     }
 299
 300     /* All IDs match: only need to check one ID */
 301     *ret = cid;
 302     return 1;
 303 }
 304
 305 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
 306                                STACK_OF(OCSP_SINGLERESP) *sresp)
 307 {
 308     /* If only one ID to match then do it */
 309     if (cid) {
 310         const EVP_MD *dgst;
 311         X509_NAME *iname;
 312         int mdlen;
 313         unsigned char md[EVP_MAX_MD_SIZE];
 314         if ((dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm))
 315                 == NULL) {
 316             OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID,
 317                     OCSP_R_UNKNOWN_MESSAGE_DIGEST);
 318             return -1;
 319         }
 320
 321         mdlen = EVP_MD_size(dgst);
 322         if (mdlen < 0)
 323             return -1;
 324         if ((cid->issuerNameHash.length != mdlen) ||
 325             (cid->issuerKeyHash.length != mdlen))
 326             return 0;
 327         iname = X509_get_subject_name(cert);
 328         if (!X509_NAME_digest(iname, dgst, md, NULL))
 329             return -1;
 330         if (memcmp(md, cid->issuerNameHash.data, mdlen))
 331             return 0;
 332         X509_pubkey_digest(cert, dgst, md, NULL);
 333         if (memcmp(md, cid->issuerKeyHash.data, mdlen))
 334             return 0;
 335
 336         return 1;
 337
 338     } else {
 339         /* We have to match the whole lot */
 340         int i, ret;
 341         OCSP_CERTID *tmpid;
 342         for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) {
 343             tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 344             ret = ocsp_match_issuerid(cert, tmpid, NULL);
 345             if (ret <= 0)
 346                 return ret;
 347         }
 348         return 1;
 349     }
 350
 351 }
 352
 353 static int ocsp_check_delegated(X509 *x, int flags)
 354 {
 355     if ((X509_get_extension_flags(x) & EXFLAG_XKUSAGE)
 356         && (X509_get_extended_key_usage(x) & XKU_OCSP_SIGN))
 357         return 1;
 358     OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
 359     return 0;
 360 }
 361
 362 /*
 363  * Verify an OCSP request. This is fortunately much easier than OCSP response
 364  * verify. Just find the signers certificate and verify it against a given
 365  * trust value.
 366  */
 367
 368 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
 369                         X509_STORE *store, unsigned long flags)
 370 {
 371     X509 *signer;
 372     X509_NAME *nm;
 373     GENERAL_NAME *gen;
 374     int ret;
 375     X509_STORE_CTX ctx;
 376     if (!req->optionalSignature) {
 377         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
 378         return 0;
 379     }
 380     gen = req->tbsRequest.requestorName;
 381     if (!gen || gen->type != GEN_DIRNAME) {
 382         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 383                 OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
 384         return 0;
 385     }
 386     nm = gen->d.directoryName;
 387     ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
 388     if (ret <= 0) {
 389         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 390                 OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 391         return 0;
 392     }
 393     if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 394         flags |= OCSP_NOVERIFY;
 395     if (!(flags & OCSP_NOSIGS)) {
 396         EVP_PKEY *skey;
 397         skey = X509_get0_pubkey(signer);
 398         ret = OCSP_REQUEST_verify(req, skey);
 399         if (ret <= 0) {
 400             OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 401             return 0;
 402         }
 403     }
 404     if (!(flags & OCSP_NOVERIFY)) {
 405         int init_res;
 406         if (flags & OCSP_NOCHAIN)
 407             init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
 408         else
 409             init_res = X509_STORE_CTX_init(&ctx, store, signer,
 410                                            req->optionalSignature->certs);
 411         if (!init_res) {
 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             ret = X509_STORE_CTX_get_error(&ctx);
 422             OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 423                     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,
 433                                 X509_NAME *nm, STACK_OF(X509) *certs,
 434                                 X509_STORE *st, unsigned long flags)
 435 {
 436     X509 *signer;
 437     if (!(flags & OCSP_NOINTERN)) {
 438         signer = X509_find_by_subject(req->optionalSignature->certs, nm);
 439         if (signer) {
 440             *psigner = signer;
 441             return 1;
 442         }
 443     }
 444
 445     signer = X509_find_by_subject(certs, nm);
 446     if (signer) {
 447         *psigner = signer;
 448         return 2;
 449     }
 450     return 0;
 451 }