2 * Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
11 #include "internal/cryptlib.h"
12 #include <openssl/objects.h>
13 #include <openssl/ts.h>
14 #include <openssl/pkcs7.h>
17 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
18 X509 *signer, STACK_OF(X509) **chain);
19 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
20 STACK_OF(X509) *chain);
21 static ESS_SIGNING_CERT *ess_get_signing_cert(PKCS7_SIGNER_INFO *si);
22 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert);
23 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert);
24 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
25 PKCS7 *token, TS_TST_INFO *tst_info);
26 static int ts_check_status_info(TS_RESP *response);
27 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
28 static int ts_check_policy(const ASN1_OBJECT *req_oid,
29 const TS_TST_INFO *tst_info);
30 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
32 unsigned char **imprint, unsigned *imprint_len);
33 static int ts_check_imprints(X509_ALGOR *algor_a,
34 const unsigned char *imprint_a, unsigned len_a,
35 TS_TST_INFO *tst_info);
36 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
37 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
38 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names,
42 * This must be large enough to hold all values in ts_status_text (with
43 * comma separator) or all text fields in ts_failure_info (also with comma).
45 #define TS_STATUS_BUF_SIZE 256
48 * Local mapping between response codes and descriptions.
50 static const char *ts_status_text[] = {
56 "revocationNotification"
59 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
64 } ts_failure_info[] = {
65 {TS_INFO_BAD_ALG, "badAlg"},
66 {TS_INFO_BAD_REQUEST, "badRequest"},
67 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
68 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
69 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
70 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
71 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
72 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
77 * This function carries out the following tasks:
78 * - Checks if there is one and only one signer.
79 * - Search for the signing certificate in 'certs' and in the response.
80 * - Check the extended key usage and key usage fields of the signer
81 * certificate (done by the path validation).
82 * - Build and validate the certificate path.
83 * - Check if the certificate path meets the requirements of the
84 * SigningCertificate ESS signed attribute.
85 * - Verify the signature value.
86 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
88 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
89 X509_STORE *store, X509 **signer_out)
91 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
92 PKCS7_SIGNER_INFO *si;
93 STACK_OF(X509) *signers = NULL;
95 STACK_OF(X509) *chain = NULL;
97 int i, j = 0, ret = 0;
100 /* Some sanity checks first. */
102 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
105 if (!PKCS7_type_is_signed(token)) {
106 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
109 sinfos = PKCS7_get_signer_info(token);
110 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
111 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
114 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
115 if (PKCS7_get_detached(token)) {
116 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
121 * Get hold of the signer certificate, search only internal certificates
122 * if it was requested.
124 signers = PKCS7_get0_signers(token, certs, 0);
125 if (!signers || sk_X509_num(signers) != 1)
127 signer = sk_X509_value(signers, 0);
129 if (!ts_verify_cert(store, certs, signer, &chain))
131 if (!ts_check_signing_certs(si, chain))
133 p7bio = PKCS7_dataInit(token, NULL);
135 /* We now have to 'read' from p7bio to calculate digests etc. */
136 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
139 j = PKCS7_signatureVerify(p7bio, token, si, signer);
141 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
146 *signer_out = signer;
153 sk_X509_pop_free(chain, X509_free);
154 sk_X509_free(signers);
160 * The certificate chain is returned in chain. Caller is responsible for
161 * freeing the vector.
163 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
164 X509 *signer, STACK_OF(X509) **chain)
166 X509_STORE_CTX *cert_ctx = NULL;
171 cert_ctx = X509_STORE_CTX_new();
172 if (cert_ctx == NULL) {
173 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
176 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
178 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
179 i = X509_verify_cert(cert_ctx);
181 int j = X509_STORE_CTX_get_error(cert_ctx);
182 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
183 ERR_add_error_data(2, "Verify error:",
184 X509_verify_cert_error_string(j));
187 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
195 X509_STORE_CTX_free(cert_ctx);
199 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
200 STACK_OF(X509) *chain)
202 ESS_SIGNING_CERT *ss = ess_get_signing_cert(si);
203 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
210 cert_ids = ss->cert_ids;
211 cert = sk_X509_value(chain, 0);
212 if (ts_find_cert(cert_ids, cert) != 0)
216 * Check the other certificates of the chain if there are more than one
217 * certificate ids in cert_ids.
219 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
220 for (i = 1; i < sk_X509_num(chain); ++i) {
221 cert = sk_X509_value(chain, i);
222 if (ts_find_cert(cert_ids, cert) < 0)
229 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
230 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
231 ESS_SIGNING_CERT_free(ss);
235 static ESS_SIGNING_CERT *ess_get_signing_cert(PKCS7_SIGNER_INFO *si)
238 const unsigned char *p;
239 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
242 p = attr->value.sequence->data;
243 return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
246 /* Returns < 0 if certificate is not found, certificate index otherwise. */
247 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
250 unsigned char cert_sha1[SHA_DIGEST_LENGTH];
252 if (!cert_ids || !cert)
255 X509_digest(cert, EVP_sha1(), cert_sha1, NULL);
257 /* Recompute SHA1 hash of certificate if necessary (side effect). */
258 X509_check_purpose(cert, -1, 0);
260 /* Look for cert in the cert_ids vector. */
261 for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
262 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
264 if (cid->hash->length == SHA_DIGEST_LENGTH
265 && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
266 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
267 if (!is || !ts_issuer_serial_cmp(is, cert))
275 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
277 GENERAL_NAME *issuer;
279 if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
282 issuer = sk_GENERAL_NAME_value(is->issuer, 0);
283 if (issuer->type != GEN_DIRNAME
284 || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
287 if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
294 * Verifies whether 'response' contains a valid response with regards
295 * to the settings of the context:
296 * - Gives an error message if the TS_TST_INFO is not present.
297 * - Calls _TS_RESP_verify_token to verify the token content.
299 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
301 PKCS7 *token = response->token;
302 TS_TST_INFO *tst_info = response->tst_info;
305 if (!ts_check_status_info(response))
307 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
316 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
317 * calls the internal int_TS_RESP_verify_token function for verifying it.
319 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
321 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
324 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
325 TS_TST_INFO_free(tst_info);
331 * Verifies whether the 'token' contains a valid time stamp token
332 * with regards to the settings of the context. Only those checks are
333 * carried out that are specified in the context:
334 * - Verifies the signature of the TS_TST_INFO.
335 * - Checks the version number of the response.
336 * - Check if the requested and returned policies math.
337 * - Check if the message imprints are the same.
338 * - Check if the nonces are the same.
339 * - Check if the TSA name matches the signer.
340 * - Check if the TSA name is the expected TSA.
342 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
343 PKCS7 *token, TS_TST_INFO *tst_info)
346 GENERAL_NAME *tsa_name = tst_info->tsa;
347 X509_ALGOR *md_alg = NULL;
348 unsigned char *imprint = NULL;
349 unsigned imprint_len = 0;
351 int flags = ctx->flags;
353 /* Some options require us to also check the signature */
354 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
355 || (flags & TS_VFY_TSA_NAME)) {
356 flags |= TS_VFY_SIGNATURE;
359 if ((flags & TS_VFY_SIGNATURE)
360 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
362 if ((flags & TS_VFY_VERSION)
363 && TS_TST_INFO_get_version(tst_info) != 1) {
364 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
367 if ((flags & TS_VFY_POLICY)
368 && !ts_check_policy(ctx->policy, tst_info))
370 if ((flags & TS_VFY_IMPRINT)
371 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
374 if ((flags & TS_VFY_DATA)
375 && (!ts_compute_imprint(ctx->data, tst_info,
376 &md_alg, &imprint, &imprint_len)
377 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
379 if ((flags & TS_VFY_NONCE)
380 && !ts_check_nonces(ctx->nonce, tst_info))
382 if ((flags & TS_VFY_SIGNER)
383 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
384 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
387 if ((flags & TS_VFY_TSA_NAME)
388 && !ts_check_signer_name(ctx->tsa_name, signer)) {
389 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
396 X509_ALGOR_free(md_alg);
397 OPENSSL_free(imprint);
401 static int ts_check_status_info(TS_RESP *response)
403 TS_STATUS_INFO *info = response->status_info;
404 long status = ASN1_INTEGER_get(info->status);
405 const char *status_text = NULL;
406 char *embedded_status_text = NULL;
407 char failure_text[TS_STATUS_BUF_SIZE] = "";
409 if (status == 0 || status == 1)
412 /* There was an error, get the description in status_text. */
413 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
414 status_text = ts_status_text[status];
416 status_text = "unknown code";
418 if (sk_ASN1_UTF8STRING_num(info->text) > 0
419 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
422 /* Fill in failure_text with the failure information. */
423 if (info->failure_info) {
426 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
427 if (ASN1_BIT_STRING_get_bit(info->failure_info,
428 ts_failure_info[i].code)) {
430 strcat(failure_text, ",");
433 strcat(failure_text, ts_failure_info[i].text);
437 if (failure_text[0] == '\0')
438 strcpy(failure_text, "unspecified");
440 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
441 ERR_add_error_data(6,
442 "status code: ", status_text,
443 ", status text: ", embedded_status_text ?
444 embedded_status_text : "unspecified",
445 ", failure codes: ", failure_text);
446 OPENSSL_free(embedded_status_text);
451 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
458 for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) {
459 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
460 if (ASN1_STRING_length(current) > TS_MAX_STATUS_LENGTH - length - 1)
462 length += ASN1_STRING_length(current);
463 length += 1; /* separator character */
465 if ((result = OPENSSL_malloc(length)) == NULL) {
466 TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE);
470 for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i) {
471 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
472 length = ASN1_STRING_length(current);
475 strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
483 static int ts_check_policy(const ASN1_OBJECT *req_oid,
484 const TS_TST_INFO *tst_info)
486 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
488 if (OBJ_cmp(req_oid, resp_oid) != 0) {
489 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
496 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
498 unsigned char **imprint, unsigned *imprint_len)
500 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
501 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
503 EVP_MD_CTX *md_ctx = NULL;
504 unsigned char buffer[4096];
510 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
512 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
513 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
516 length = EVP_MD_size(md);
519 *imprint_len = length;
520 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
521 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
525 md_ctx = EVP_MD_CTX_new();
526 if (md_ctx == NULL) {
527 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
530 if (!EVP_DigestInit(md_ctx, md))
532 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
533 if (!EVP_DigestUpdate(md_ctx, buffer, length))
536 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
538 EVP_MD_CTX_free(md_ctx);
542 EVP_MD_CTX_free(md_ctx);
543 X509_ALGOR_free(*md_alg);
544 OPENSSL_free(*imprint);
550 static int ts_check_imprints(X509_ALGOR *algor_a,
551 const unsigned char *imprint_a, unsigned len_a,
552 TS_TST_INFO *tst_info)
554 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
555 X509_ALGOR *algor_b = b->hash_algo;
559 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
562 /* The parameter must be NULL in both. */
563 if ((algor_a->parameter
564 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
565 || (algor_b->parameter
566 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
570 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
571 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
574 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
578 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
580 const ASN1_INTEGER *b = tst_info->nonce;
583 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
587 /* No error if a nonce is returned without being requested. */
588 if (ASN1_INTEGER_cmp(a, b) != 0) {
589 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
597 * Check if the specified TSA name matches either the subject or one of the
598 * subject alternative names of the TSA certificate.
600 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
602 STACK_OF(GENERAL_NAME) *gen_names = NULL;
606 if (tsa_name->type == GEN_DIRNAME
607 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
609 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
610 while (gen_names != NULL) {
611 found = ts_find_name(gen_names, tsa_name) >= 0;
615 * Get the next subject alternative name, although there should be no
618 GENERAL_NAMES_free(gen_names);
619 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
621 GENERAL_NAMES_free(gen_names);
626 /* Returns 1 if name is in gen_names, 0 otherwise. */
627 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
630 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
631 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
632 found = GENERAL_NAME_cmp(current, name) == 0;
634 return found ? i - 1 : -1;