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, unsigned long flags);
  66 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
  67 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain);
  68 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp,
  69                           OCSP_CERTID **ret);
  70 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
  71                                STACK_OF(OCSP_SINGLERESP) *sresp);
  72 static int ocsp_check_delegated(X509 *x);
  73 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
  74                                 X509_NAME *nm, STACK_OF(X509) *certs,
  75                                 unsigned long flags);
  76
  77 /* Verify a basic response message */
  78
  79 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
  80                       X509_STORE *st, unsigned long flags)
  81 {
  82     X509 *signer, *x;
  83     STACK_OF(X509) *chain = NULL;
  84     STACK_OF(X509) *untrusted = NULL;
  85     X509_STORE_CTX ctx;
  86     int i, ret = ocsp_find_signer(&signer, bs, certs, flags);
  87
  88     if (!ret) {
  89         OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
  90                 OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
  91         goto end;
  92     }
  93     if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
  94         flags |= OCSP_NOVERIFY;
  95     if (!(flags & OCSP_NOSIGS)) {
  96         EVP_PKEY *skey;
  97         skey = X509_get0_pubkey(signer);
  98         if (skey)
  99             ret = OCSP_BASICRESP_verify(bs, skey, 0);
 100         if (!skey || ret <= 0) {
 101             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 102             goto end;
 103         }
 104     }
 105     if (!(flags & OCSP_NOVERIFY)) {
 106         int init_res;
 107         if (flags & OCSP_NOCHAIN) {
 108             untrusted = NULL;
 109         } else if (bs->certs && certs) {
 110             untrusted = sk_X509_dup(bs->certs);
 111             for (i = 0; i < sk_X509_num(certs); i++) {
 112                 if (!sk_X509_push(untrusted, sk_X509_value(certs, i))) {
 113                     OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
 114                     goto end;
 115                 }
 116             }
 117         } else {
 118             untrusted = bs->certs;
 119         }
 120         init_res = X509_STORE_CTX_init(&ctx, st, signer, untrusted);
 121         if (!init_res) {
 122             ret = -1;
 123             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_X509_LIB);
 124             goto end;
 125         }
 126
 127         X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
 128         ret = X509_verify_cert(&ctx);
 129         chain = X509_STORE_CTX_get1_chain(&ctx);
 130         X509_STORE_CTX_cleanup(&ctx);
 131         if (ret <= 0) {
 132             i = X509_STORE_CTX_get_error(&ctx);
 133             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
 134                     OCSP_R_CERTIFICATE_VERIFY_ERROR);
 135             ERR_add_error_data(2, "Verify error:",
 136                                X509_verify_cert_error_string(i));
 137             goto end;
 138         }
 139         if (flags & OCSP_NOCHECKS) {
 140             ret = 1;
 141             goto end;
 142         }
 143         /*
 144          * At this point we have a valid certificate chain need to verify it
 145          * against the OCSP issuer criteria.
 146          */
 147         ret = ocsp_check_issuer(bs, chain);
 148
 149         /* If fatal error or valid match then finish */
 150         if (ret != 0)
 151             goto end;
 152
 153         /*
 154          * Easy case: explicitly trusted. Get root CA and check for explicit
 155          * trust
 156          */
 157         if (flags & OCSP_NOEXPLICIT)
 158             goto end;
 159
 160         x = sk_X509_value(chain, sk_X509_num(chain) - 1);
 161         if (X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) {
 162             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_ROOT_CA_NOT_TRUSTED);
 163             goto end;
 164         }
 165         ret = 1;
 166     }
 167
 168  end:
 169     sk_X509_pop_free(chain, X509_free);
 170     if (bs->certs && certs)
 171         sk_X509_free(untrusted);
 172     return ret;
 173 }
 174
 175 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
 176                             STACK_OF(X509) *certs, unsigned long flags)
 177 {
 178     X509 *signer;
 179     OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
 180     if ((signer = ocsp_find_signer_sk(certs, rid))) {
 181         *psigner = signer;
 182         return 2;
 183     }
 184     if (!(flags & OCSP_NOINTERN) &&
 185         (signer = ocsp_find_signer_sk(bs->certs, rid))) {
 186         *psigner = signer;
 187         return 1;
 188     }
 189     /* Maybe lookup from store if by subject name */
 190
 191     *psigner = NULL;
 192     return 0;
 193 }
 194
 195 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
 196 {
 197     int i;
 198     unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
 199     X509 *x;
 200
 201     /* Easy if lookup by name */
 202     if (id->type == V_OCSP_RESPID_NAME)
 203         return X509_find_by_subject(certs, id->value.byName);
 204
 205     /* Lookup by key hash */
 206
 207     /* If key hash isn't SHA1 length then forget it */
 208     if (id->value.byKey->length != SHA_DIGEST_LENGTH)
 209         return NULL;
 210     keyhash = id->value.byKey->data;
 211     /* Calculate hash of each key and compare */
 212     for (i = 0; i < sk_X509_num(certs); i++) {
 213         x = sk_X509_value(certs, i);
 214         X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
 215         if (!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
 216             return x;
 217     }
 218     return NULL;
 219 }
 220
 221 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain)
 222 {
 223     STACK_OF(OCSP_SINGLERESP) *sresp;
 224     X509 *signer, *sca;
 225     OCSP_CERTID *caid = NULL;
 226     int i;
 227     sresp = bs->tbsResponseData.responses;
 228
 229     if (sk_X509_num(chain) <= 0) {
 230         OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
 231         return -1;
 232     }
 233
 234     /* See if the issuer IDs match. */
 235     i = ocsp_check_ids(sresp, &caid);
 236
 237     /* If ID mismatch or other error then return */
 238     if (i <= 0)
 239         return i;
 240
 241     signer = sk_X509_value(chain, 0);
 242     /* Check to see if OCSP responder CA matches request CA */
 243     if (sk_X509_num(chain) > 1) {
 244         sca = sk_X509_value(chain, 1);
 245         i = ocsp_match_issuerid(sca, caid, sresp);
 246         if (i < 0)
 247             return i;
 248         if (i) {
 249             /* We have a match, if extensions OK then success */
 250             if (ocsp_check_delegated(signer))
 251                 return 1;
 252             return 0;
 253         }
 254     }
 255
 256     /* Otherwise check if OCSP request signed directly by request CA */
 257     return ocsp_match_issuerid(signer, caid, sresp);
 258 }
 259
 260 /*
 261  * Check the issuer certificate IDs for equality. If there is a mismatch with
 262  * the same algorithm then there's no point trying to match any certificates
 263  * against the issuer. If the issuer IDs all match then we just need to check
 264  * equality against one of them.
 265  */
 266
 267 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
 268 {
 269     OCSP_CERTID *tmpid, *cid;
 270     int i, idcount;
 271
 272     idcount = sk_OCSP_SINGLERESP_num(sresp);
 273     if (idcount <= 0) {
 274         OCSPerr(OCSP_F_OCSP_CHECK_IDS,
 275                 OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
 276         return -1;
 277     }
 278
 279     cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
 280
 281     *ret = NULL;
 282
 283     for (i = 1; i < idcount; i++) {
 284         tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 285         /* Check to see if IDs match */
 286         if (OCSP_id_issuer_cmp(cid, tmpid)) {
 287             /* If algorithm mismatch let caller deal with it */
 288             if (OBJ_cmp(tmpid->hashAlgorithm.algorithm,
 289                         cid->hashAlgorithm.algorithm))
 290                 return 2;
 291             /* Else mismatch */
 292             return 0;
 293         }
 294     }
 295
 296     /* All IDs match: only need to check one ID */
 297     *ret = cid;
 298     return 1;
 299 }
 300
 301 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
 302                                STACK_OF(OCSP_SINGLERESP) *sresp)
 303 {
 304     /* If only one ID to match then do it */
 305     if (cid) {
 306         const EVP_MD *dgst;
 307         X509_NAME *iname;
 308         int mdlen;
 309         unsigned char md[EVP_MAX_MD_SIZE];
 310         if ((dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm))
 311                 == NULL) {
 312             OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID,
 313                     OCSP_R_UNKNOWN_MESSAGE_DIGEST);
 314             return -1;
 315         }
 316
 317         mdlen = EVP_MD_size(dgst);
 318         if (mdlen < 0)
 319             return -1;
 320         if ((cid->issuerNameHash.length != mdlen) ||
 321             (cid->issuerKeyHash.length != mdlen))
 322             return 0;
 323         iname = X509_get_subject_name(cert);
 324         if (!X509_NAME_digest(iname, dgst, md, NULL))
 325             return -1;
 326         if (memcmp(md, cid->issuerNameHash.data, mdlen))
 327             return 0;
 328         X509_pubkey_digest(cert, dgst, md, NULL);
 329         if (memcmp(md, cid->issuerKeyHash.data, mdlen))
 330             return 0;
 331
 332         return 1;
 333
 334     } else {
 335         /* We have to match the whole lot */
 336         int i, ret;
 337         OCSP_CERTID *tmpid;
 338         for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) {
 339             tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
 340             ret = ocsp_match_issuerid(cert, tmpid, NULL);
 341             if (ret <= 0)
 342                 return ret;
 343         }
 344         return 1;
 345     }
 346
 347 }
 348
 349 static int ocsp_check_delegated(X509 *x)
 350 {
 351     if ((X509_get_extension_flags(x) & EXFLAG_XKUSAGE)
 352         && (X509_get_extended_key_usage(x) & XKU_OCSP_SIGN))
 353         return 1;
 354     OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
 355     return 0;
 356 }
 357
 358 /*
 359  * Verify an OCSP request. This is fortunately much easier than OCSP response
 360  * verify. Just find the signers certificate and verify it against a given
 361  * trust value.
 362  */
 363
 364 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
 365                         X509_STORE *store, unsigned long flags)
 366 {
 367     X509 *signer;
 368     X509_NAME *nm;
 369     GENERAL_NAME *gen;
 370     int ret;
 371     X509_STORE_CTX ctx;
 372     if (!req->optionalSignature) {
 373         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
 374         return 0;
 375     }
 376     gen = req->tbsRequest.requestorName;
 377     if (!gen || gen->type != GEN_DIRNAME) {
 378         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 379                 OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
 380         return 0;
 381     }
 382     nm = gen->d.directoryName;
 383     ret = ocsp_req_find_signer(&signer, req, nm, certs, flags);
 384     if (ret <= 0) {
 385         OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 386                 OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
 387         return 0;
 388     }
 389     if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
 390         flags |= OCSP_NOVERIFY;
 391     if (!(flags & OCSP_NOSIGS)) {
 392         EVP_PKEY *skey;
 393         skey = X509_get0_pubkey(signer);
 394         ret = OCSP_REQUEST_verify(req, skey);
 395         if (ret <= 0) {
 396             OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
 397             return 0;
 398         }
 399     }
 400     if (!(flags & OCSP_NOVERIFY)) {
 401         int init_res;
 402         if (flags & OCSP_NOCHAIN)
 403             init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
 404         else
 405             init_res = X509_STORE_CTX_init(&ctx, store, signer,
 406                                            req->optionalSignature->certs);
 407         if (!init_res) {
 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             ret = X509_STORE_CTX_get_error(&ctx);
 418             OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
 419                     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,
 429                                 X509_NAME *nm, STACK_OF(X509) *certs,
 430                                 unsigned long flags)
 431 {
 432     X509 *signer;
 433     if (!(flags & OCSP_NOINTERN)) {
 434         signer = X509_find_by_subject(req->optionalSignature->certs, nm);
 435         if (signer) {
 436             *psigner = signer;
 437             return 1;
 438         }
 439     }
 440
 441     signer = X509_find_by_subject(certs, nm);
 442     if (signer) {
 443         *psigner = signer;
 444         return 2;
 445     }
 446     return 0;
 447 }