crypto/ts/ts_rsp_verify.c

   1 /*
   2  * Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/objects.h>
  13 #include <openssl/ts.h>
  14 #include <openssl/pkcs7.h>
  15 #include "ts_local.h"
  16 #include "crypto/ess.h"
  17
  18 DEFINE_STACK_OF(PKCS7_SIGNER_INFO)
  19 DEFINE_STACK_OF(X509)
  20 DEFINE_STACK_OF(ESS_CERT_ID)
  21 DEFINE_STACK_OF(ESS_CERT_ID_V2)
  22 DEFINE_STACK_OF(ASN1_UTF8STRING)
  23 DEFINE_STACK_OF(GENERAL_NAME)
  24
  25 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
  26                           X509 *signer, STACK_OF(X509) **chain);
  27 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
  28                                   STACK_OF(X509) *chain);
  29 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert);
  30 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert);
  31 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
  32                                     PKCS7 *token, TS_TST_INFO *tst_info);
  33 static int ts_check_status_info(TS_RESP *response);
  34 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
  35 static int ts_check_policy(const ASN1_OBJECT *req_oid,
  36                            const TS_TST_INFO *tst_info);
  37 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
  38                               X509_ALGOR **md_alg,
  39                               unsigned char **imprint, unsigned *imprint_len);
  40 static int ts_check_imprints(X509_ALGOR *algor_a,
  41                              const unsigned char *imprint_a, unsigned len_a,
  42                              TS_TST_INFO *tst_info);
  43 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
  44 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
  45 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names,
  46                         GENERAL_NAME *name);
  47 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert);
  48
  49 /*
  50  * This must be large enough to hold all values in ts_status_text (with
  51  * comma separator) or all text fields in ts_failure_info (also with comma).
  52  */
  53 #define TS_STATUS_BUF_SIZE      256
  54
  55 /*
  56  * Local mapping between response codes and descriptions.
  57  */
  58 static const char *ts_status_text[] = {
  59     "granted",
  60     "grantedWithMods",
  61     "rejection",
  62     "waiting",
  63     "revocationWarning",
  64     "revocationNotification"
  65 };
  66
  67 #define TS_STATUS_TEXT_SIZE     OSSL_NELEM(ts_status_text)
  68
  69 static struct {
  70     int code;
  71     const char *text;
  72 } ts_failure_info[] = {
  73     {TS_INFO_BAD_ALG, "badAlg"},
  74     {TS_INFO_BAD_REQUEST, "badRequest"},
  75     {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
  76     {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
  77     {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
  78     {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
  79     {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
  80     {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
  81 };
  82
  83
  84 /*-
  85  * This function carries out the following tasks:
  86  *      - Checks if there is one and only one signer.
  87  *      - Search for the signing certificate in 'certs' and in the response.
  88  *      - Check the extended key usage and key usage fields of the signer
  89  *      certificate (done by the path validation).
  90  *      - Build and validate the certificate path.
  91  *      - Check if the certificate path meets the requirements of the
  92  *      SigningCertificate ESS signed attribute.
  93  *      - Verify the signature value.
  94  *      - Returns the signer certificate in 'signer', if 'signer' is not NULL.
  95  */
  96 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
  97                              X509_STORE *store, X509 **signer_out)
  98 {
  99     STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
 100     PKCS7_SIGNER_INFO *si;
 101     STACK_OF(X509) *signers = NULL;
 102     X509 *signer;
 103     STACK_OF(X509) *chain = NULL;
 104     char buf[4096];
 105     int i, j = 0, ret = 0;
 106     BIO *p7bio = NULL;
 107
 108     /* Some sanity checks first. */
 109     if (!token) {
 110         TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
 111         goto err;
 112     }
 113     if (!PKCS7_type_is_signed(token)) {
 114         TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
 115         goto err;
 116     }
 117     sinfos = PKCS7_get_signer_info(token);
 118     if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
 119         TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
 120         goto err;
 121     }
 122     si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
 123     if (PKCS7_get_detached(token)) {
 124         TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
 125         goto err;
 126     }
 127
 128     /*
 129      * Get hold of the signer certificate, search only internal certificates
 130      * if it was requested.
 131      */
 132     signers = PKCS7_get0_signers(token, certs, 0);
 133     if (!signers || sk_X509_num(signers) != 1)
 134         goto err;
 135     signer = sk_X509_value(signers, 0);
 136
 137     if (!ts_verify_cert(store, certs, signer, &chain))
 138         goto err;
 139     if (!ts_check_signing_certs(si, chain))
 140         goto err;
 141     p7bio = PKCS7_dataInit(token, NULL);
 142
 143     /* We now have to 'read' from p7bio to calculate digests etc. */
 144     while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
 145         continue;
 146
 147     j = PKCS7_signatureVerify(p7bio, token, si, signer);
 148     if (j <= 0) {
 149         TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
 150         goto err;
 151     }
 152
 153     if (signer_out) {
 154         *signer_out = signer;
 155         X509_up_ref(signer);
 156     }
 157     ret = 1;
 158
 159  err:
 160     BIO_free_all(p7bio);
 161     sk_X509_pop_free(chain, X509_free);
 162     sk_X509_free(signers);
 163
 164     return ret;
 165 }
 166
 167 /*
 168  * The certificate chain is returned in chain. Caller is responsible for
 169  * freeing the vector.
 170  */
 171 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
 172                           X509 *signer, STACK_OF(X509) **chain)
 173 {
 174     X509_STORE_CTX *cert_ctx = NULL;
 175     int i;
 176     int ret = 0;
 177
 178     *chain = NULL;
 179     cert_ctx = X509_STORE_CTX_new();
 180     if (cert_ctx == NULL) {
 181         TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
 182         goto err;
 183     }
 184     if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
 185         goto end;
 186     X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
 187     i = X509_verify_cert(cert_ctx);
 188     if (i <= 0) {
 189         int j = X509_STORE_CTX_get_error(cert_ctx);
 190         TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
 191         ERR_add_error_data(2, "Verify error:",
 192                            X509_verify_cert_error_string(j));
 193         goto err;
 194     }
 195     *chain = X509_STORE_CTX_get1_chain(cert_ctx);
 196     ret = 1;
 197     goto end;
 198
 199 err:
 200     ret = 0;
 201
 202 end:
 203     X509_STORE_CTX_free(cert_ctx);
 204     return ret;
 205 }
 206
 207 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
 208                                   STACK_OF(X509) *chain)
 209 {
 210     ESS_SIGNING_CERT *ss = ESS_SIGNING_CERT_get(si);
 211     STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
 212     ESS_SIGNING_CERT_V2 *ssv2 = ESS_SIGNING_CERT_V2_get(si);
 213     STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
 214     X509 *cert;
 215     int i = 0;
 216     int ret = 0;
 217
 218     if (ss != NULL) {
 219         cert_ids = ss->cert_ids;
 220         cert = sk_X509_value(chain, 0);
 221         if (ts_find_cert(cert_ids, cert) != 0)
 222             goto err;
 223
 224         /*
 225          * Check the other certificates of the chain if there are more than one
 226          * certificate ids in cert_ids.
 227          */
 228         if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
 229             for (i = 1; i < sk_X509_num(chain); ++i) {
 230                 cert = sk_X509_value(chain, i);
 231                 if (ts_find_cert(cert_ids, cert) < 0)
 232                     goto err;
 233             }
 234         }
 235     } else if (ssv2 != NULL) {
 236         cert_ids_v2 = ssv2->cert_ids;
 237         cert = sk_X509_value(chain, 0);
 238         if (ts_find_cert_v2(cert_ids_v2, cert) != 0)
 239             goto err;
 240
 241         /*
 242          * Check the other certificates of the chain if there are more than one
 243          * certificate ids in cert_ids.
 244          */
 245         if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
 246             for (i = 1; i < sk_X509_num(chain); ++i) {
 247                 cert = sk_X509_value(chain, i);
 248                 if (ts_find_cert_v2(cert_ids_v2, cert) < 0)
 249                     goto err;
 250             }
 251         }
 252     } else {
 253         goto err;
 254     }
 255
 256     ret = 1;
 257  err:
 258     if (!ret)
 259         TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
 260               TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
 261     ESS_SIGNING_CERT_free(ss);
 262     ESS_SIGNING_CERT_V2_free(ssv2);
 263     return ret;
 264 }
 265
 266 /* Returns < 0 if certificate is not found, certificate index otherwise. */
 267 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
 268 {
 269     int i;
 270     unsigned char cert_sha1[SHA_DIGEST_LENGTH];
 271
 272     if (!cert_ids || !cert)
 273         return -1;
 274
 275     /* Recompute SHA1 hash of certificate if necessary (side effect). */
 276     X509_check_purpose(cert, -1, 0);
 277
 278     if (!X509_digest(cert, EVP_sha1(), cert_sha1, NULL))
 279         return -1;
 280
 281     /* Look for cert in the cert_ids vector. */
 282     for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
 283         ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
 284
 285         if (cid->hash->length == SHA_DIGEST_LENGTH
 286             && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
 287             ESS_ISSUER_SERIAL *is = cid->issuer_serial;
 288             if (!is || !ts_issuer_serial_cmp(is, cert))
 289                 return i;
 290         }
 291     }
 292
 293     return -1;
 294 }
 295
 296 /* Returns < 0 if certificate is not found, certificate index otherwise. */
 297 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert)
 298 {
 299     int i;
 300     unsigned char cert_digest[EVP_MAX_MD_SIZE];
 301     unsigned int len;
 302
 303     /* Look for cert in the cert_ids vector. */
 304     for (i = 0; i < sk_ESS_CERT_ID_V2_num(cert_ids); ++i) {
 305         ESS_CERT_ID_V2 *cid = sk_ESS_CERT_ID_V2_value(cert_ids, i);
 306         const EVP_MD *md;
 307
 308         if (cid->hash_alg != NULL)
 309             md = EVP_get_digestbyobj(cid->hash_alg->algorithm);
 310         else
 311             md = EVP_sha256();
 312
 313         if (!X509_digest(cert, md, cert_digest, &len))
 314             return -1;
 315         if (cid->hash->length != (int)len)
 316             return -1;
 317
 318         if (memcmp(cid->hash->data, cert_digest, cid->hash->length) == 0) {
 319             ESS_ISSUER_SERIAL *is = cid->issuer_serial;
 320
 321             if (is == NULL || !ts_issuer_serial_cmp(is, cert))
 322                 return i;
 323         }
 324     }
 325
 326     return -1;
 327 }
 328
 329 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
 330 {
 331     GENERAL_NAME *issuer;
 332
 333     if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
 334         return -1;
 335
 336     issuer = sk_GENERAL_NAME_value(is->issuer, 0);
 337     if (issuer->type != GEN_DIRNAME
 338         || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
 339         return -1;
 340
 341     if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
 342         return -1;
 343
 344     return 0;
 345 }
 346
 347 /*-
 348  * Verifies whether 'response' contains a valid response with regards
 349  * to the settings of the context:
 350  *      - Gives an error message if the TS_TST_INFO is not present.
 351  *      - Calls _TS_RESP_verify_token to verify the token content.
 352  */
 353 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
 354 {
 355     PKCS7 *token = response->token;
 356     TS_TST_INFO *tst_info = response->tst_info;
 357     int ret = 0;
 358
 359     if (!ts_check_status_info(response))
 360         goto err;
 361     if (!int_ts_RESP_verify_token(ctx, token, tst_info))
 362         goto err;
 363     ret = 1;
 364
 365  err:
 366     return ret;
 367 }
 368
 369 /*
 370  * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
 371  * calls the internal int_TS_RESP_verify_token function for verifying it.
 372  */
 373 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
 374 {
 375     TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
 376     int ret = 0;
 377     if (tst_info) {
 378         ret = int_ts_RESP_verify_token(ctx, token, tst_info);
 379         TS_TST_INFO_free(tst_info);
 380     }
 381     return ret;
 382 }
 383
 384 /*-
 385  * Verifies whether the 'token' contains a valid time stamp token
 386  * with regards to the settings of the context. Only those checks are
 387  * carried out that are specified in the context:
 388  *      - Verifies the signature of the TS_TST_INFO.
 389  *      - Checks the version number of the response.
 390  *      - Check if the requested and returned policies math.
 391  *      - Check if the message imprints are the same.
 392  *      - Check if the nonces are the same.
 393  *      - Check if the TSA name matches the signer.
 394  *      - Check if the TSA name is the expected TSA.
 395  */
 396 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
 397                                     PKCS7 *token, TS_TST_INFO *tst_info)
 398 {
 399     X509 *signer = NULL;
 400     GENERAL_NAME *tsa_name = tst_info->tsa;
 401     X509_ALGOR *md_alg = NULL;
 402     unsigned char *imprint = NULL;
 403     unsigned imprint_len = 0;
 404     int ret = 0;
 405     int flags = ctx->flags;
 406
 407     /* Some options require us to also check the signature */
 408     if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
 409             || (flags & TS_VFY_TSA_NAME)) {
 410         flags |= TS_VFY_SIGNATURE;
 411     }
 412
 413     if ((flags & TS_VFY_SIGNATURE)
 414         && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
 415         goto err;
 416     if ((flags & TS_VFY_VERSION)
 417         && TS_TST_INFO_get_version(tst_info) != 1) {
 418         TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
 419         goto err;
 420     }
 421     if ((flags & TS_VFY_POLICY)
 422         && !ts_check_policy(ctx->policy, tst_info))
 423         goto err;
 424     if ((flags & TS_VFY_IMPRINT)
 425         && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
 426                               tst_info))
 427         goto err;
 428     if ((flags & TS_VFY_DATA)
 429         && (!ts_compute_imprint(ctx->data, tst_info,
 430                                 &md_alg, &imprint, &imprint_len)
 431             || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
 432         goto err;
 433     if ((flags & TS_VFY_NONCE)
 434         && !ts_check_nonces(ctx->nonce, tst_info))
 435         goto err;
 436     if ((flags & TS_VFY_SIGNER)
 437         && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
 438         TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
 439         goto err;
 440     }
 441     if ((flags & TS_VFY_TSA_NAME)
 442         && !ts_check_signer_name(ctx->tsa_name, signer)) {
 443         TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
 444         goto err;
 445     }
 446     ret = 1;
 447
 448  err:
 449     X509_free(signer);
 450     X509_ALGOR_free(md_alg);
 451     OPENSSL_free(imprint);
 452     return ret;
 453 }
 454
 455 static int ts_check_status_info(TS_RESP *response)
 456 {
 457     TS_STATUS_INFO *info = response->status_info;
 458     long status = ASN1_INTEGER_get(info->status);
 459     const char *status_text = NULL;
 460     char *embedded_status_text = NULL;
 461     char failure_text[TS_STATUS_BUF_SIZE] = "";
 462
 463     if (status == 0 || status == 1)
 464         return 1;
 465
 466     /* There was an error, get the description in status_text. */
 467     if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
 468         status_text = ts_status_text[status];
 469     else
 470         status_text = "unknown code";
 471
 472     if (sk_ASN1_UTF8STRING_num(info->text) > 0
 473         && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
 474         return 0;
 475
 476     /* Fill in failure_text with the failure information. */
 477     if (info->failure_info) {
 478         int i;
 479         int first = 1;
 480         for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
 481             if (ASN1_BIT_STRING_get_bit(info->failure_info,
 482                                         ts_failure_info[i].code)) {
 483                 if (!first)
 484                     strcat(failure_text, ",");
 485                 else
 486                     first = 0;
 487                 strcat(failure_text, ts_failure_info[i].text);
 488             }
 489         }
 490     }
 491     if (failure_text[0] == '\0')
 492         strcpy(failure_text, "unspecified");
 493
 494     TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
 495     ERR_add_error_data(6,
 496                        "status code: ", status_text,
 497                        ", status text: ", embedded_status_text ?
 498                        embedded_status_text : "unspecified",
 499                        ", failure codes: ", failure_text);
 500     OPENSSL_free(embedded_status_text);
 501
 502     return 0;
 503 }
 504
 505 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
 506 {
 507     return sk_ASN1_UTF8STRING2text(text, "/", TS_MAX_STATUS_LENGTH);
 508 }
 509
 510 static int ts_check_policy(const ASN1_OBJECT *req_oid,
 511                            const TS_TST_INFO *tst_info)
 512 {
 513     const ASN1_OBJECT *resp_oid = tst_info->policy_id;
 514
 515     if (OBJ_cmp(req_oid, resp_oid) != 0) {
 516         TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
 517         return 0;
 518     }
 519
 520     return 1;
 521 }
 522
 523 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
 524                               X509_ALGOR **md_alg,
 525                               unsigned char **imprint, unsigned *imprint_len)
 526 {
 527     TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
 528     X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
 529     const EVP_MD *md;
 530     EVP_MD_CTX *md_ctx = NULL;
 531     unsigned char buffer[4096];
 532     int length;
 533
 534     *md_alg = NULL;
 535     *imprint = NULL;
 536
 537     if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
 538         goto err;
 539     if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
 540         TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
 541         goto err;
 542     }
 543     length = EVP_MD_size(md);
 544     if (length < 0)
 545         goto err;
 546     *imprint_len = length;
 547     if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
 548         TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
 549         goto err;
 550     }
 551
 552     md_ctx = EVP_MD_CTX_new();
 553     if (md_ctx == NULL) {
 554         TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
 555         goto err;
 556     }
 557     if (!EVP_DigestInit(md_ctx, md))
 558         goto err;
 559     while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
 560         if (!EVP_DigestUpdate(md_ctx, buffer, length))
 561             goto err;
 562     }
 563     if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
 564         goto err;
 565     EVP_MD_CTX_free(md_ctx);
 566
 567     return 1;
 568  err:
 569     EVP_MD_CTX_free(md_ctx);
 570     X509_ALGOR_free(*md_alg);
 571     OPENSSL_free(*imprint);
 572     *imprint_len = 0;
 573     *imprint = 0;
 574     return 0;
 575 }
 576
 577 static int ts_check_imprints(X509_ALGOR *algor_a,
 578                              const unsigned char *imprint_a, unsigned len_a,
 579                              TS_TST_INFO *tst_info)
 580 {
 581     TS_MSG_IMPRINT *b = tst_info->msg_imprint;
 582     X509_ALGOR *algor_b = b->hash_algo;
 583     int ret = 0;
 584
 585     if (algor_a) {
 586         if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
 587             goto err;
 588
 589         /* The parameter must be NULL in both. */
 590         if ((algor_a->parameter
 591              && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
 592             || (algor_b->parameter
 593                 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
 594             goto err;
 595     }
 596
 597     ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
 598         memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
 599  err:
 600     if (!ret)
 601         TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
 602     return ret;
 603 }
 604
 605 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
 606 {
 607     const ASN1_INTEGER *b = tst_info->nonce;
 608
 609     if (!b) {
 610         TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
 611         return 0;
 612     }
 613
 614     /* No error if a nonce is returned without being requested. */
 615     if (ASN1_INTEGER_cmp(a, b) != 0) {
 616         TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
 617         return 0;
 618     }
 619
 620     return 1;
 621 }
 622
 623 /*
 624  * Check if the specified TSA name matches either the subject or one of the
 625  * subject alternative names of the TSA certificate.
 626  */
 627 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
 628 {
 629     STACK_OF(GENERAL_NAME) *gen_names = NULL;
 630     int idx = -1;
 631     int found = 0;
 632
 633     if (tsa_name->type == GEN_DIRNAME
 634         && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
 635         return 1;
 636     gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
 637     while (gen_names != NULL) {
 638         found = ts_find_name(gen_names, tsa_name) >= 0;
 639         if (found)
 640             break;
 641         /*
 642          * Get the next subject alternative name, although there should be no
 643          * more than one.
 644          */
 645         GENERAL_NAMES_free(gen_names);
 646         gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
 647     }
 648     GENERAL_NAMES_free(gen_names);
 649
 650     return found;
 651 }
 652
 653 /* Returns 1 if name is in gen_names, 0 otherwise. */
 654 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
 655 {
 656     int i, found;
 657     for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
 658         GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
 659         found = GENERAL_NAME_cmp(current, name) == 0;
 660     }
 661     return found ? i - 1 : -1;
 662 }