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(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info);
29 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
31 unsigned char **imprint, unsigned *imprint_len);
32 static int ts_check_imprints(X509_ALGOR *algor_a,
33 unsigned char *imprint_a, unsigned len_a,
34 TS_TST_INFO *tst_info);
35 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
36 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
37 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names,
41 * This must be large enough to hold all values in ts_status_text (with
42 * comma separator) or all text fields in ts_failure_info (also with comma).
44 #define TS_STATUS_BUF_SIZE 256
47 * Local mapping between response codes and descriptions.
49 static const char *ts_status_text[] = {
55 "revocationNotification"
58 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
63 } ts_failure_info[] = {
64 {TS_INFO_BAD_ALG, "badAlg"},
65 {TS_INFO_BAD_REQUEST, "badRequest"},
66 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
67 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
68 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
69 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
70 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
71 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
76 * This function carries out the following tasks:
77 * - Checks if there is one and only one signer.
78 * - Search for the signing certificate in 'certs' and in the response.
79 * - Check the extended key usage and key usage fields of the signer
80 * certificate (done by the path validation).
81 * - Build and validate the certificate path.
82 * - Check if the certificate path meets the requirements of the
83 * SigningCertificate ESS signed attribute.
84 * - Verify the signature value.
85 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
87 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
88 X509_STORE *store, X509 **signer_out)
90 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
91 PKCS7_SIGNER_INFO *si;
92 STACK_OF(X509) *signers = NULL;
94 STACK_OF(X509) *chain = NULL;
96 int i, j = 0, ret = 0;
99 /* Some sanity checks first. */
101 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
104 if (!PKCS7_type_is_signed(token)) {
105 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
108 sinfos = PKCS7_get_signer_info(token);
109 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
110 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
113 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
114 if (PKCS7_get_detached(token)) {
115 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
120 * Get hold of the signer certificate, search only internal certificates
121 * if it was requested.
123 signers = PKCS7_get0_signers(token, certs, 0);
124 if (!signers || sk_X509_num(signers) != 1)
126 signer = sk_X509_value(signers, 0);
128 if (!ts_verify_cert(store, certs, signer, &chain))
130 if (!ts_check_signing_certs(si, chain))
132 p7bio = PKCS7_dataInit(token, NULL);
134 /* We now have to 'read' from p7bio to calculate digests etc. */
135 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
138 j = PKCS7_signatureVerify(p7bio, token, si, signer);
140 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
145 *signer_out = signer;
152 sk_X509_pop_free(chain, X509_free);
153 sk_X509_free(signers);
159 * The certificate chain is returned in chain. Caller is responsible for
160 * freeing the vector.
162 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
163 X509 *signer, STACK_OF(X509) **chain)
165 X509_STORE_CTX *cert_ctx = NULL;
170 cert_ctx = X509_STORE_CTX_new();
171 if (cert_ctx == NULL) {
172 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
175 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
177 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
178 i = X509_verify_cert(cert_ctx);
180 int j = X509_STORE_CTX_get_error(cert_ctx);
181 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
182 ERR_add_error_data(2, "Verify error:",
183 X509_verify_cert_error_string(j));
186 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
194 X509_STORE_CTX_free(cert_ctx);
198 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
199 STACK_OF(X509) *chain)
201 ESS_SIGNING_CERT *ss = ess_get_signing_cert(si);
202 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
209 cert_ids = ss->cert_ids;
210 cert = sk_X509_value(chain, 0);
211 if (ts_find_cert(cert_ids, cert) != 0)
215 * Check the other certificates of the chain if there are more than one
216 * certificate ids in cert_ids.
218 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
219 for (i = 1; i < sk_X509_num(chain); ++i) {
220 cert = sk_X509_value(chain, i);
221 if (ts_find_cert(cert_ids, cert) < 0)
228 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
229 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
230 ESS_SIGNING_CERT_free(ss);
234 static ESS_SIGNING_CERT *ess_get_signing_cert(PKCS7_SIGNER_INFO *si)
237 const unsigned char *p;
238 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
241 p = attr->value.sequence->data;
242 return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
245 /* Returns < 0 if certificate is not found, certificate index otherwise. */
246 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
249 unsigned char cert_sha1[SHA_DIGEST_LENGTH];
251 if (!cert_ids || !cert)
254 X509_digest(cert, EVP_sha1(), cert_sha1, NULL);
256 /* Recompute SHA1 hash of certificate if necessary (side effect). */
257 X509_check_purpose(cert, -1, 0);
259 /* Look for cert in the cert_ids vector. */
260 for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
261 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
263 if (cid->hash->length == SHA_DIGEST_LENGTH
264 && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
265 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
266 if (!is || !ts_issuer_serial_cmp(is, cert))
274 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
276 GENERAL_NAME *issuer;
278 if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
281 issuer = sk_GENERAL_NAME_value(is->issuer, 0);
282 if (issuer->type != GEN_DIRNAME
283 || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
286 if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
293 * Verifies whether 'response' contains a valid response with regards
294 * to the settings of the context:
295 * - Gives an error message if the TS_TST_INFO is not present.
296 * - Calls _TS_RESP_verify_token to verify the token content.
298 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
300 PKCS7 *token = response->token;
301 TS_TST_INFO *tst_info = response->tst_info;
304 if (!ts_check_status_info(response))
306 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
315 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
316 * calls the internal int_TS_RESP_verify_token function for verifying it.
318 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
320 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
323 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
324 TS_TST_INFO_free(tst_info);
330 * Verifies whether the 'token' contains a valid time stamp token
331 * with regards to the settings of the context. Only those checks are
332 * carried out that are specified in the context:
333 * - Verifies the signature of the TS_TST_INFO.
334 * - Checks the version number of the response.
335 * - Check if the requested and returned policies math.
336 * - Check if the message imprints are the same.
337 * - Check if the nonces are the same.
338 * - Check if the TSA name matches the signer.
339 * - Check if the TSA name is the expected TSA.
341 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
342 PKCS7 *token, TS_TST_INFO *tst_info)
345 GENERAL_NAME *tsa_name = tst_info->tsa;
346 X509_ALGOR *md_alg = NULL;
347 unsigned char *imprint = NULL;
348 unsigned imprint_len = 0;
351 if ((ctx->flags & TS_VFY_SIGNATURE)
352 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
354 if ((ctx->flags & TS_VFY_VERSION)
355 && TS_TST_INFO_get_version(tst_info) != 1) {
356 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
359 if ((ctx->flags & TS_VFY_POLICY)
360 && !ts_check_policy(ctx->policy, tst_info))
362 if ((ctx->flags & TS_VFY_IMPRINT)
363 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
366 if ((ctx->flags & TS_VFY_DATA)
367 && (!ts_compute_imprint(ctx->data, tst_info,
368 &md_alg, &imprint, &imprint_len)
369 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
371 if ((ctx->flags & TS_VFY_NONCE)
372 && !ts_check_nonces(ctx->nonce, tst_info))
374 if ((ctx->flags & TS_VFY_SIGNER)
375 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
376 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
379 if ((ctx->flags & TS_VFY_TSA_NAME)
380 && !ts_check_signer_name(ctx->tsa_name, signer)) {
381 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
388 X509_ALGOR_free(md_alg);
389 OPENSSL_free(imprint);
393 static int ts_check_status_info(TS_RESP *response)
395 TS_STATUS_INFO *info = response->status_info;
396 long status = ASN1_INTEGER_get(info->status);
397 const char *status_text = NULL;
398 char *embedded_status_text = NULL;
399 char failure_text[TS_STATUS_BUF_SIZE] = "";
401 if (status == 0 || status == 1)
404 /* There was an error, get the description in status_text. */
405 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
406 status_text = ts_status_text[status];
408 status_text = "unknown code";
410 if (sk_ASN1_UTF8STRING_num(info->text) > 0
411 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
414 /* Fill in failure_text with the failure information. */
415 if (info->failure_info) {
418 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
419 if (ASN1_BIT_STRING_get_bit(info->failure_info,
420 ts_failure_info[i].code)) {
422 strcat(failure_text, ",");
425 strcat(failure_text, ts_failure_info[i].text);
429 if (failure_text[0] == '\0')
430 strcpy(failure_text, "unspecified");
432 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
433 ERR_add_error_data(6,
434 "status code: ", status_text,
435 ", status text: ", embedded_status_text ?
436 embedded_status_text : "unspecified",
437 ", failure codes: ", failure_text);
438 OPENSSL_free(embedded_status_text);
443 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
446 unsigned int length = 0;
450 for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) {
451 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
452 length += ASN1_STRING_length(current);
453 length += 1; /* separator character */
455 if ((result = OPENSSL_malloc(length)) == NULL) {
456 TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE);
460 for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i) {
461 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
462 length = ASN1_STRING_length(current);
465 strncpy(p, (const char *)ASN1_STRING_data(current), length);
473 static int ts_check_policy(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info)
475 ASN1_OBJECT *resp_oid = tst_info->policy_id;
477 if (OBJ_cmp(req_oid, resp_oid) != 0) {
478 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
485 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
487 unsigned char **imprint, unsigned *imprint_len)
489 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
490 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
492 EVP_MD_CTX *md_ctx = NULL;
493 unsigned char buffer[4096];
499 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
501 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
502 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
505 length = EVP_MD_size(md);
508 *imprint_len = length;
509 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
510 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
514 md_ctx = EVP_MD_CTX_new();
515 if (md_ctx == NULL) {
516 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
519 if (!EVP_DigestInit(md_ctx, md))
521 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
522 if (!EVP_DigestUpdate(md_ctx, buffer, length))
525 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
527 EVP_MD_CTX_free(md_ctx);
531 EVP_MD_CTX_free(md_ctx);
532 X509_ALGOR_free(*md_alg);
533 OPENSSL_free(*imprint);
539 static int ts_check_imprints(X509_ALGOR *algor_a,
540 unsigned char *imprint_a, unsigned len_a,
541 TS_TST_INFO *tst_info)
543 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
544 X509_ALGOR *algor_b = b->hash_algo;
548 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
551 /* The parameter must be NULL in both. */
552 if ((algor_a->parameter
553 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
554 || (algor_b->parameter
555 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
559 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
560 memcmp(imprint_a, ASN1_STRING_data(b->hashed_msg), len_a) == 0;
563 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
567 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
569 const ASN1_INTEGER *b = tst_info->nonce;
572 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
576 /* No error if a nonce is returned without being requested. */
577 if (ASN1_INTEGER_cmp(a, b) != 0) {
578 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
586 * Check if the specified TSA name matches either the subject or one of the
587 * subject alternative names of the TSA certificate.
589 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
591 STACK_OF(GENERAL_NAME) *gen_names = NULL;
595 if (tsa_name->type == GEN_DIRNAME
596 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
598 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
599 while (gen_names != NULL) {
600 found = ts_find_name(gen_names, tsa_name) >= 0;
604 * Get the next subject alternative name, although there should be no
607 GENERAL_NAMES_free(gen_names);
608 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
610 GENERAL_NAMES_free(gen_names);
615 /* Returns 1 if name is in gen_names, 0 otherwise. */
616 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
619 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
620 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
621 found = GENERAL_NAME_cmp(current, name) == 0;
623 return found ? i - 1 : -1;