crypto/ts/ts_rsp_verify.c

   1 /* crypto/ts/ts_resp_verify.c */
   2 /* Written by Zoltan Glozik (zglozik@stones.com) for the OpenSSL
   3  * project 2002.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2006 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 <stdio.h>
  60 #include "cryptlib.h"
  61 #include <openssl/objects.h>
  62 #include <openssl/ts.h>
  63 #include <openssl/pkcs7.h>
  64
  65 /* Private function declarations. */
  66
  67 static int TS_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
  68                           X509 *signer, STACK_OF(X509) **chain);
  69 static int TS_check_signing_certs(PKCS7_SIGNER_INFO *si, STACK_OF(X509) *chain);
  70 static ESS_SIGNING_CERT *ESS_get_signing_cert(PKCS7_SIGNER_INFO *si);
  71 static int TS_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert);
  72 static int TS_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509_CINF *cinfo);
  73 static int int_TS_RESP_verify_token(TS_VERIFY_CTX *ctx,
  74                                  PKCS7 *token, TS_TST_INFO *tst_info);
  75 static int TS_check_status_info(TS_RESP *response);
  76 static char *TS_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
  77 static int TS_check_policy(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info);
  78 static int TS_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
  79                               X509_ALGOR **md_alg,
  80                               unsigned char **imprint, unsigned *imprint_len);
  81 static int TS_check_imprints(X509_ALGOR *algor_a,
  82                              unsigned char *imprint_a, unsigned len_a,
  83                              TS_TST_INFO *tst_info);
  84 static int TS_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
  85 static int TS_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
  86 static int TS_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name);
  87
  88 /*
  89  * Local mapping between response codes and descriptions.
  90  * Don't forget to change TS_STATUS_BUF_SIZE when modifying
  91  * the elements of this array.
  92  */
  93 static const char *TS_status_text[] =
  94         { "granted",
  95           "grantedWithMods",
  96           "rejection",
  97           "waiting",
  98           "revocationWarning",
  99           "revocationNotification" };
 100
 101 #define TS_STATUS_TEXT_SIZE     (sizeof(TS_status_text)/sizeof(*TS_status_text))
 102
 103 /*
 104  * This must be greater or equal to the sum of the strings in TS_status_text
 105  * plus the number of its elements.
 106  */
 107 #define TS_STATUS_BUF_SIZE      256
 108
 109 static struct
 110         {
 111         int code;
 112         const char *text;
 113         } TS_failure_info[] =
 114                 { { TS_INFO_BAD_ALG, "badAlg" },
 115                   { TS_INFO_BAD_REQUEST, "badRequest" },
 116                   { TS_INFO_BAD_DATA_FORMAT, "badDataFormat" },
 117                   { TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable" },
 118                   { TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy" },
 119                   { TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension" },
 120                   { TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable" },
 121                   { TS_INFO_SYSTEM_FAILURE, "systemFailure" } };
 122
 123 #define TS_FAILURE_INFO_SIZE    (sizeof(TS_failure_info) / \
 124                                 sizeof(*TS_failure_info))
 125
 126 /* Functions for verifying a signed TS_TST_INFO structure. */
 127
 128 /*
 129  * This function carries out the following tasks:
 130  *      - Checks if there is one and only one signer.
 131  *      - Search for the signing certificate in 'certs' and in the response.
 132  *      - Check the extended key usage and key usage fields of the signer
 133  *      certificate (done by the path validation).
 134  *      - Build and validate the certificate path.
 135  *      - Check if the certificate path meets the requirements of the
 136  *      SigningCertificate ESS signed attribute.
 137  *      - Verify the signature value.
 138  *      - Returns the signer certificate in 'signer', if 'signer' is not NULL.
 139  */
 140 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
 141                              X509_STORE *store, X509 **signer_out)
 142         {
 143         STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
 144         PKCS7_SIGNER_INFO *si;
 145         STACK_OF(X509) *signers = NULL;
 146         X509    *signer;
 147         STACK_OF(X509) *chain = NULL;
 148         char    buf[4096];
 149         int     i, j = 0, ret = 0;
 150         BIO     *p7bio = NULL;
 151
 152         /* Some sanity checks first. */
 153         if (!token)
 154                 {
 155                 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
 156                 goto err;
 157                 }
 158
 159         /* Check for the correct content type */
 160         if(!PKCS7_type_is_signed(token))
 161                 {
 162                 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
 163                 goto err;
 164                 }
 165
 166         /* Check if there is one and only one signer. */
 167         sinfos = PKCS7_get_signer_info(token);
 168         if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1)
 169                 {
 170                 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE,
 171                       TS_R_THERE_MUST_BE_ONE_SIGNER);
 172                 goto err;
 173                 }
 174         si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
 175
 176         /* Check for no content: no data to verify signature. */
 177         if (PKCS7_get_detached(token))
 178                 {
 179                 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
 180                 goto err;
 181                 }
 182
 183         /* Get hold of the signer certificate, search only internal
 184            certificates if it was requested. */
 185         signers = PKCS7_get0_signers(token, certs, 0);
 186         if (!signers || sk_X509_num(signers) != 1) goto err;
 187         signer = sk_X509_value(signers, 0);
 188
 189         /* Now verify the certificate. */
 190         if (!TS_verify_cert(store, certs, signer, &chain)) goto err;
 191
 192         /* Check if the signer certificate is consistent with the
 193            ESS extension. */
 194         if (!TS_check_signing_certs(si, chain)) goto err;
 195
 196         /* Creating the message digest. */
 197         p7bio = PKCS7_dataInit(token, NULL);
 198
 199         /* We now have to 'read' from p7bio to calculate digests etc. */
 200         while ((i = BIO_read(p7bio,buf,sizeof(buf))) > 0);
 201
 202         /* Verifying the signature. */
 203         j = PKCS7_signatureVerify(p7bio, token, si, signer);
 204         if (j <= 0)
 205                 {
 206                 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
 207                 goto err;
 208                 }
 209
 210         /* Return the signer certificate if needed. */
 211         if (signer_out)
 212                 {
 213                 *signer_out = signer;
 214                 CRYPTO_add(&signer->references, 1, CRYPTO_LOCK_X509);
 215                 }
 216
 217         ret = 1;
 218
 219  err:
 220         BIO_free_all(p7bio);
 221         sk_X509_pop_free(chain, X509_free);
 222         sk_X509_free(signers);
 223
 224         return ret;
 225         }
 226
 227 /*
 228  * The certificate chain is returned in chain. Caller is responsible for
 229  * freeing the vector.
 230  */
 231 static int TS_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
 232                           X509 *signer, STACK_OF(X509) **chain)
 233         {
 234         X509_STORE_CTX  cert_ctx;
 235         int i;
 236         int ret = 1;
 237
 238         /* chain is an out argument. */
 239         *chain = NULL;
 240         X509_STORE_CTX_init(&cert_ctx, store, signer, untrusted);
 241         X509_STORE_CTX_set_purpose(&cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
 242         i = X509_verify_cert(&cert_ctx);
 243         if (i <= 0)
 244                 {
 245                 int j = X509_STORE_CTX_get_error(&cert_ctx);
 246                 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
 247                 ERR_add_error_data(2, "Verify error:",
 248                                    X509_verify_cert_error_string(j));
 249                 ret = 0;
 250                 }
 251         else
 252                 {
 253                 /* Get a copy of the certificate chain. */
 254                 *chain = X509_STORE_CTX_get1_chain(&cert_ctx);
 255                 }
 256
 257         X509_STORE_CTX_cleanup(&cert_ctx);
 258
 259         return ret;
 260         }
 261
 262 static int TS_check_signing_certs(PKCS7_SIGNER_INFO *si, STACK_OF(X509) *chain)
 263         {
 264         ESS_SIGNING_CERT *ss = ESS_get_signing_cert(si);
 265         STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
 266         X509 *cert;
 267         int i = 0;
 268         int ret = 0;
 269
 270         if (!ss) goto err;
 271         cert_ids = ss->cert_ids;
 272         /* The signer certificate must be the first in cert_ids. */
 273         cert = sk_X509_value(chain, 0);
 274         if (TS_find_cert(cert_ids, cert) != 0) goto err;
 275
 276         /* Check the other certificates of the chain if there are more
 277            than one certificate ids in cert_ids. */
 278         if (sk_ESS_CERT_ID_num(cert_ids) > 1)
 279                 {
 280                 /* All the certificates of the chain must be in cert_ids. */
 281                 for (i = 1; i < sk_X509_num(chain); ++i)
 282                         {
 283                         cert = sk_X509_value(chain, i);
 284                         if (TS_find_cert(cert_ids, cert) < 0) goto err;
 285                         }
 286                 }
 287         ret = 1;
 288  err:
 289         if (!ret)
 290                 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
 291                       TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
 292         ESS_SIGNING_CERT_free(ss);
 293         return ret;
 294         }
 295
 296 static ESS_SIGNING_CERT *ESS_get_signing_cert(PKCS7_SIGNER_INFO *si)
 297         {
 298         ASN1_TYPE *attr;
 299         const unsigned char *p;
 300         attr = PKCS7_get_signed_attribute(si,
 301                                           NID_id_smime_aa_signingCertificate);
 302         if (!attr) return NULL;
 303         p = attr->value.sequence->data;
 304         return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
 305         }
 306
 307 /* Returns < 0 if certificate is not found, certificate index otherwise. */
 308 static int TS_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
 309         {
 310         int i;
 311
 312         if (!cert_ids || !cert) return -1;
 313
 314         /* Recompute SHA1 hash of certificate if necessary (side effect). */
 315         X509_check_purpose(cert, -1, 0);
 316
 317         /* Look for cert in the cert_ids vector. */
 318         for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i)
 319                 {
 320                 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
 321
 322                 /* Check the SHA-1 hash first. */
 323                 if (cid->hash->length == sizeof(cert->sha1_hash)
 324                     && !memcmp(cid->hash->data, cert->sha1_hash,
 325                                sizeof(cert->sha1_hash)))
 326                         {
 327                         /* Check the issuer/serial as well if specified. */
 328                         ESS_ISSUER_SERIAL *is = cid->issuer_serial;
 329                         if (!is || !TS_issuer_serial_cmp(is, cert->cert_info))
 330                                 return i;
 331                         }
 332                 }
 333
 334         return -1;
 335         }
 336
 337 static int TS_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509_CINF *cinfo)
 338         {
 339         GENERAL_NAME *issuer;
 340
 341         if (!is || !cinfo || sk_GENERAL_NAME_num(is->issuer) != 1) return -1;
 342
 343         /* Check the issuer first. It must be a directory name. */
 344         issuer = sk_GENERAL_NAME_value(is->issuer, 0);
 345         if (issuer->type != GEN_DIRNAME
 346             || X509_NAME_cmp(issuer->d.dirn, cinfo->issuer))
 347                 return -1;
 348
 349         /* Check the serial number, too. */
 350         if (ASN1_INTEGER_cmp(is->serial, cinfo->serialNumber))
 351                 return -1;
 352
 353         return 0;
 354         }
 355
 356 /*
 357  * Verifies whether 'response' contains a valid response with regards
 358  * to the settings of the context:
 359  *      - Gives an error message if the TS_TST_INFO is not present.
 360  *      - Calls _TS_RESP_verify_token to verify the token content.
 361  */
 362 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
 363         {
 364         PKCS7 *token = TS_RESP_get_token(response);
 365         TS_TST_INFO *tst_info = TS_RESP_get_tst_info(response);
 366         int ret = 0;
 367
 368         /* Check if we have a successful TS_TST_INFO object in place. */
 369         if (!TS_check_status_info(response)) goto err;
 370
 371         /* Check the contents of the time stamp token. */
 372         if (!int_TS_RESP_verify_token(ctx, token, tst_info))
 373                 goto err;
 374
 375         ret = 1;
 376  err:
 377         return ret;
 378         }
 379
 380 /*
 381  * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
 382  * calls the internal int_TS_RESP_verify_token function for verifying it.
 383  */
 384 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
 385         {
 386         TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
 387         int ret = 0;
 388         if (tst_info)
 389                 {
 390                 ret = int_TS_RESP_verify_token(ctx, token, tst_info);
 391                 TS_TST_INFO_free(tst_info);
 392                 }
 393         return ret;
 394         }
 395
 396 /*-
 397  * Verifies whether the 'token' contains a valid time stamp token
 398  * with regards to the settings of the context. Only those checks are
 399  * carried out that are specified in the context:
 400  *      - Verifies the signature of the TS_TST_INFO.
 401  *      - Checks the version number of the response.
 402  *      - Check if the requested and returned policies math.
 403  *      - Check if the message imprints are the same.
 404  *      - Check if the nonces are the same.
 405  *      - Check if the TSA name matches the signer.
 406  *      - Check if the TSA name is the expected TSA.
 407  */
 408 static int int_TS_RESP_verify_token(TS_VERIFY_CTX *ctx,
 409                                  PKCS7 *token, TS_TST_INFO *tst_info)
 410         {
 411         X509 *signer = NULL;
 412         GENERAL_NAME *tsa_name = TS_TST_INFO_get_tsa(tst_info);
 413         X509_ALGOR *md_alg = NULL;
 414         unsigned char *imprint = NULL;
 415         unsigned imprint_len = 0;
 416         int ret = 0;
 417
 418         /* Verify the signature. */
 419         if ((ctx->flags & TS_VFY_SIGNATURE)
 420             && !TS_RESP_verify_signature(token, ctx->certs, ctx->store,
 421                                          &signer))
 422                 goto err;
 423
 424         /* Check version number of response. */
 425         if ((ctx->flags & TS_VFY_VERSION)
 426             && TS_TST_INFO_get_version(tst_info) != 1)
 427                 {
 428                 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
 429                 goto err;
 430                 }
 431
 432         /* Check policies. */
 433         if ((ctx->flags & TS_VFY_POLICY)
 434             && !TS_check_policy(ctx->policy, tst_info))
 435                 goto err;
 436
 437         /* Check message imprints. */
 438         if ((ctx->flags & TS_VFY_IMPRINT)
 439             && !TS_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
 440                                   tst_info))
 441                 goto err;
 442
 443         /* Compute and check message imprints. */
 444         if ((ctx->flags & TS_VFY_DATA)
 445             && (!TS_compute_imprint(ctx->data, tst_info,
 446                                     &md_alg, &imprint, &imprint_len)
 447             || !TS_check_imprints(md_alg, imprint, imprint_len, tst_info)))
 448                 goto err;
 449
 450         /* Check nonces. */
 451         if ((ctx->flags & TS_VFY_NONCE)
 452             && !TS_check_nonces(ctx->nonce, tst_info))
 453                 goto err;
 454
 455         /* Check whether TSA name and signer certificate match. */
 456         if ((ctx->flags & TS_VFY_SIGNER)
 457             && tsa_name && !TS_check_signer_name(tsa_name, signer))
 458                 {
 459                 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
 460                 goto err;
 461                 }
 462
 463         /* Check whether the TSA is the expected one. */
 464         if ((ctx->flags & TS_VFY_TSA_NAME)
 465             && !TS_check_signer_name(ctx->tsa_name, signer))
 466                 {
 467                 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
 468                 goto err;
 469                 }
 470
 471         ret = 1;
 472  err:
 473         X509_free(signer);
 474         X509_ALGOR_free(md_alg);
 475         OPENSSL_free(imprint);
 476         return ret;
 477         }
 478
 479 static int TS_check_status_info(TS_RESP *response)
 480         {
 481         TS_STATUS_INFO *info = TS_RESP_get_status_info(response);
 482         long status = ASN1_INTEGER_get(info->status);
 483         const char *status_text = NULL;
 484         char *embedded_status_text = NULL;
 485         char failure_text[TS_STATUS_BUF_SIZE] = "";
 486
 487         /* Check if everything went fine. */
 488         if (status == 0 || status == 1) return 1;
 489
 490         /* There was an error, get the description in status_text. */
 491         if (0 <= status && status < (long)TS_STATUS_TEXT_SIZE)
 492                 status_text = TS_status_text[status];
 493         else
 494                 status_text = "unknown code";
 495
 496         /* Set the embedded_status_text to the returned description. */
 497         if (sk_ASN1_UTF8STRING_num(info->text) > 0
 498             && !(embedded_status_text = TS_get_status_text(info->text)))
 499                 return 0;
 500
 501         /* Filling in failure_text with the failure information. */
 502         if (info->failure_info)
 503                 {
 504                 int i;
 505                 int first = 1;
 506                 for (i = 0; i < (int)TS_FAILURE_INFO_SIZE; ++i)
 507                         {
 508                         if (ASN1_BIT_STRING_get_bit(info->failure_info,
 509                                                     TS_failure_info[i].code))
 510                                 {
 511                                 if (!first)
 512                                         strcpy(failure_text, ",");
 513                                 else
 514                                         first = 0;
 515                                 strcat(failure_text, TS_failure_info[i].text);
 516                                 }
 517                         }
 518                 }
 519         if (failure_text[0] == '\0')
 520                 strcpy(failure_text, "unspecified");
 521
 522         /* Making up the error string. */
 523         TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
 524         ERR_add_error_data(6,
 525                            "status code: ", status_text,
 526                            ", status text: ", embedded_status_text ?
 527                            embedded_status_text : "unspecified",
 528                            ", failure codes: ", failure_text);
 529         OPENSSL_free(embedded_status_text);
 530
 531         return 0;
 532         }
 533
 534 static char *TS_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
 535         {
 536         int i;
 537         unsigned int length = 0;
 538         char *result = NULL;
 539         char *p;
 540
 541         /* Determine length first. */
 542         for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i)
 543                 {
 544                 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
 545                 length += ASN1_STRING_length(current);
 546                 length += 1;    /* separator character */
 547                 }
 548         /* Allocate memory (closing '\0' included). */
 549         if (!(result = OPENSSL_malloc(length)))
 550                 {
 551                 TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE);
 552                 return NULL;
 553                 }
 554         /* Concatenate the descriptions. */
 555         for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i)
 556                 {
 557                 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
 558                 length = ASN1_STRING_length(current);
 559                 if (i > 0) *p++ = '/';
 560                 strncpy(p, (const char *)ASN1_STRING_data(current), length);
 561                 p += length;
 562                 }
 563         /* We do have space for this, too. */
 564         *p = '\0';
 565
 566         return result;
 567         }
 568
 569 static int TS_check_policy(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info)
 570         {
 571         ASN1_OBJECT *resp_oid = TS_TST_INFO_get_policy_id(tst_info);
 572
 573         if (OBJ_cmp(req_oid, resp_oid) != 0)
 574                 {
 575                 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
 576                 return 0;
 577                 }
 578
 579         return 1;
 580         }
 581
 582 static int TS_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
 583                               X509_ALGOR **md_alg,
 584                               unsigned char **imprint, unsigned *imprint_len)
 585         {
 586         TS_MSG_IMPRINT *msg_imprint = TS_TST_INFO_get_msg_imprint(tst_info);
 587         X509_ALGOR *md_alg_resp = TS_MSG_IMPRINT_get_algo(msg_imprint);
 588         const EVP_MD *md;
 589         EVP_MD_CTX md_ctx;
 590         unsigned char buffer[4096];
 591         int length;
 592
 593         *md_alg = NULL;
 594         *imprint = NULL;
 595
 596         /* Return the MD algorithm of the response. */
 597         if (!(*md_alg = X509_ALGOR_dup(md_alg_resp))) goto err;
 598
 599         /* Getting the MD object. */
 600         if (!(md = EVP_get_digestbyobj((*md_alg)->algorithm)))
 601                 {
 602                 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
 603                 goto err;
 604                 }
 605
 606         /* Compute message digest. */
 607         length = EVP_MD_size(md);
 608         if (length < 0)
 609             goto err;
 610         *imprint_len = length;
 611         if (!(*imprint = OPENSSL_malloc(*imprint_len)))
 612                 {
 613                 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
 614                 goto err;
 615                 }
 616
 617         if (!EVP_DigestInit(&md_ctx, md))
 618                 goto err;
 619         while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0)
 620                 {
 621                 if (!EVP_DigestUpdate(&md_ctx, buffer, length))
 622                         goto err;
 623                 }
 624         if (!EVP_DigestFinal(&md_ctx, *imprint, NULL))
 625                 goto err;
 626
 627         return 1;
 628  err:
 629         X509_ALGOR_free(*md_alg);
 630         OPENSSL_free(*imprint);
 631         *imprint_len = 0;
 632         *imprint = NULL;
 633         return 0;
 634         }
 635
 636 static int TS_check_imprints(X509_ALGOR *algor_a,
 637                              unsigned char *imprint_a, unsigned len_a,
 638                              TS_TST_INFO *tst_info)
 639         {
 640         TS_MSG_IMPRINT *b = TS_TST_INFO_get_msg_imprint(tst_info);
 641         X509_ALGOR *algor_b = TS_MSG_IMPRINT_get_algo(b);
 642         int ret = 0;
 643
 644         /* algor_a is optional. */
 645         if (algor_a)
 646                 {
 647                 /* Compare algorithm OIDs. */
 648                 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm)) goto err;
 649
 650                 /* The parameter must be NULL in both. */
 651                 if ((algor_a->parameter
 652                      && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
 653                     || (algor_b->parameter
 654                         && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
 655                         goto err;
 656                 }
 657
 658         /* Compare octet strings. */
 659         ret = len_a == (unsigned) ASN1_STRING_length(b->hashed_msg) &&
 660                 memcmp(imprint_a, ASN1_STRING_data(b->hashed_msg), len_a) == 0;
 661  err:
 662         if (!ret)
 663                 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
 664         return ret;
 665         }
 666
 667 static int TS_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
 668         {
 669         const ASN1_INTEGER *b = TS_TST_INFO_get_nonce(tst_info);
 670
 671         /* Error if nonce is missing. */
 672         if (!b)
 673                 {
 674                 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
 675                 return 0;
 676                 }
 677
 678         /* No error if a nonce is returned without being requested. */
 679         if (ASN1_INTEGER_cmp(a, b) != 0)
 680                 {
 681                 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
 682                 return 0;
 683                 }
 684
 685         return 1;
 686         }
 687
 688 /* Check if the specified TSA name matches either the subject
 689    or one of the subject alternative names of the TSA certificate. */
 690 static int TS_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
 691         {
 692         STACK_OF(GENERAL_NAME) *gen_names = NULL;
 693         int idx = -1;
 694         int found = 0;
 695
 696         /* Check the subject name first. */
 697         if (tsa_name->type == GEN_DIRNAME
 698             && X509_name_cmp(tsa_name->d.dirn, signer->cert_info->subject) == 0)
 699                 return 1;
 700
 701         /* Check all the alternative names. */
 702         gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name,
 703                                      NULL, &idx);
 704         while (gen_names != NULL
 705                && !(found = TS_find_name(gen_names, tsa_name) >= 0))
 706                 {
 707                 /* Get the next subject alternative name,
 708                    although there should be no more than one. */
 709                 GENERAL_NAMES_free(gen_names);
 710                 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name,
 711                                              NULL, &idx);
 712                 }
 713         if (gen_names) GENERAL_NAMES_free(gen_names);
 714
 715         return found;
 716         }
 717
 718 /* Returns 1 if name is in gen_names, 0 otherwise. */
 719 static int TS_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
 720         {
 721         int i, found;
 722         for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names);
 723              ++i)
 724                 {
 725                 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
 726                 found = GENERAL_NAME_cmp(current, name) == 0;
 727                 }
 728         return found ? i - 1 : -1;
 729         }