2 * Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include "internal/cryptlib.h"
12 #include <openssl/objects.h>
13 #include <openssl/ts.h>
14 #include <openssl/pkcs7.h>
16 #include "crypto/ess.h"
18 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
19 X509 *signer, STACK_OF(X509) **chain);
20 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
21 STACK_OF(X509) *chain);
23 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
24 PKCS7 *token, TS_TST_INFO *tst_info);
25 static int ts_check_status_info(TS_RESP *response);
26 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
27 static int ts_check_policy(const ASN1_OBJECT *req_oid,
28 const 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 const 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) *untrusted = NULL;
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 ERR_raise(ERR_LIB_TS, TS_R_INVALID_NULL_POINTER);
105 if (!PKCS7_type_is_signed(token)) {
106 ERR_raise(ERR_LIB_TS, TS_R_WRONG_CONTENT_TYPE);
109 sinfos = PKCS7_get_signer_info(token);
110 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
111 ERR_raise(ERR_LIB_TS, TS_R_THERE_MUST_BE_ONE_SIGNER);
114 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
115 if (PKCS7_get_detached(token)) {
116 ERR_raise(ERR_LIB_TS, 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 untrusted = sk_X509_new_reserve(NULL, sk_X509_num(certs)
130 + sk_X509_num(token->d.sign->cert));
131 if (untrusted == NULL
132 || !X509_add_certs(untrusted, certs, 0)
133 || !X509_add_certs(untrusted, token->d.sign->cert, 0))
135 if (!ts_verify_cert(store, untrusted, signer, &chain))
137 if (!ts_check_signing_certs(si, chain))
139 p7bio = PKCS7_dataInit(token, NULL);
141 /* We now have to 'read' from p7bio to calculate digests etc. */
142 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
145 j = PKCS7_signatureVerify(p7bio, token, si, signer);
147 ERR_raise(ERR_LIB_TS, TS_R_SIGNATURE_FAILURE);
152 *signer_out = signer;
159 sk_X509_free(untrusted);
160 sk_X509_pop_free(chain, X509_free);
161 sk_X509_free(signers);
167 * The certificate chain is returned in chain. Caller is responsible for
168 * freeing the vector.
170 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
171 X509 *signer, STACK_OF(X509) **chain)
173 X509_STORE_CTX *cert_ctx = NULL;
178 cert_ctx = X509_STORE_CTX_new();
179 if (cert_ctx == NULL) {
180 ERR_raise(ERR_LIB_TS, ERR_R_MALLOC_FAILURE);
183 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
185 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
186 i = X509_verify_cert(cert_ctx);
188 int j = X509_STORE_CTX_get_error(cert_ctx);
189 ERR_raise_data(ERR_LIB_TS, TS_R_CERTIFICATE_VERIFY_ERROR,
190 "Verify error:%s", X509_verify_cert_error_string(j));
193 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
201 X509_STORE_CTX_free(cert_ctx);
205 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
206 STACK_OF(X509) *chain)
208 ESS_SIGNING_CERT *ss = ossl_ess_signing_cert_get(si);
209 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
210 ESS_SIGNING_CERT_V2 *ssv2 = ossl_ess_signing_cert_v2_get(si);
211 STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
217 cert_ids = ss->cert_ids;
218 cert = sk_X509_value(chain, 0);
219 if (ossl_ess_find_cert(cert_ids, cert) != 0)
223 * Check the other certificates of the chain if there are more than one
224 * certificate ids in cert_ids.
226 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
227 for (i = 1; i < sk_X509_num(chain); ++i) {
228 cert = sk_X509_value(chain, i);
229 if (ossl_ess_find_cert(cert_ids, cert) < 0)
233 } else if (ssv2 != NULL) {
234 cert_ids_v2 = ssv2->cert_ids;
235 cert = sk_X509_value(chain, 0);
236 if (ossl_ess_find_cert_v2(cert_ids_v2, cert) != 0)
240 * Check the other certificates of the chain if there are more than one
241 * certificate ids in cert_ids.
243 if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
244 for (i = 1; i < sk_X509_num(chain); ++i) {
245 cert = sk_X509_value(chain, i);
246 if (ossl_ess_find_cert_v2(cert_ids_v2, cert) < 0)
257 ERR_raise(ERR_LIB_TS, TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
258 ESS_SIGNING_CERT_free(ss);
259 ESS_SIGNING_CERT_V2_free(ssv2);
264 * Verifies whether 'response' contains a valid response with regards
265 * to the settings of the context:
266 * - Gives an error message if the TS_TST_INFO is not present.
267 * - Calls _TS_RESP_verify_token to verify the token content.
269 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
271 PKCS7 *token = response->token;
272 TS_TST_INFO *tst_info = response->tst_info;
275 if (!ts_check_status_info(response))
277 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
286 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
287 * calls the internal int_TS_RESP_verify_token function for verifying it.
289 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
291 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
294 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
295 TS_TST_INFO_free(tst_info);
301 * Verifies whether the 'token' contains a valid time stamp token
302 * with regards to the settings of the context. Only those checks are
303 * carried out that are specified in the context:
304 * - Verifies the signature of the TS_TST_INFO.
305 * - Checks the version number of the response.
306 * - Check if the requested and returned policies math.
307 * - Check if the message imprints are the same.
308 * - Check if the nonces are the same.
309 * - Check if the TSA name matches the signer.
310 * - Check if the TSA name is the expected TSA.
312 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
313 PKCS7 *token, TS_TST_INFO *tst_info)
316 GENERAL_NAME *tsa_name = tst_info->tsa;
317 X509_ALGOR *md_alg = NULL;
318 unsigned char *imprint = NULL;
319 unsigned imprint_len = 0;
321 int flags = ctx->flags;
323 /* Some options require us to also check the signature */
324 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
325 || (flags & TS_VFY_TSA_NAME)) {
326 flags |= TS_VFY_SIGNATURE;
329 if ((flags & TS_VFY_SIGNATURE)
330 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
332 if ((flags & TS_VFY_VERSION)
333 && TS_TST_INFO_get_version(tst_info) != 1) {
334 ERR_raise(ERR_LIB_TS, TS_R_UNSUPPORTED_VERSION);
337 if ((flags & TS_VFY_POLICY)
338 && !ts_check_policy(ctx->policy, tst_info))
340 if ((flags & TS_VFY_IMPRINT)
341 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
344 if ((flags & TS_VFY_DATA)
345 && (!ts_compute_imprint(ctx->data, tst_info,
346 &md_alg, &imprint, &imprint_len)
347 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
349 if ((flags & TS_VFY_NONCE)
350 && !ts_check_nonces(ctx->nonce, tst_info))
352 if ((flags & TS_VFY_SIGNER)
353 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
354 ERR_raise(ERR_LIB_TS, TS_R_TSA_NAME_MISMATCH);
357 if ((flags & TS_VFY_TSA_NAME)
358 && !ts_check_signer_name(ctx->tsa_name, signer)) {
359 ERR_raise(ERR_LIB_TS, TS_R_TSA_UNTRUSTED);
366 X509_ALGOR_free(md_alg);
367 OPENSSL_free(imprint);
371 static int ts_check_status_info(TS_RESP *response)
373 TS_STATUS_INFO *info = response->status_info;
374 long status = ASN1_INTEGER_get(info->status);
375 const char *status_text = NULL;
376 char *embedded_status_text = NULL;
377 char failure_text[TS_STATUS_BUF_SIZE] = "";
379 if (status == 0 || status == 1)
382 /* There was an error, get the description in status_text. */
383 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
384 status_text = ts_status_text[status];
386 status_text = "unknown code";
388 if (sk_ASN1_UTF8STRING_num(info->text) > 0
389 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
392 /* Fill in failure_text with the failure information. */
393 if (info->failure_info) {
396 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
397 if (ASN1_BIT_STRING_get_bit(info->failure_info,
398 ts_failure_info[i].code)) {
400 strcat(failure_text, ",");
403 strcat(failure_text, ts_failure_info[i].text);
407 if (failure_text[0] == '\0')
408 strcpy(failure_text, "unspecified");
410 ERR_raise_data(ERR_LIB_TS, TS_R_NO_TIME_STAMP_TOKEN,
411 "status code: %s, status text: %s, failure codes: %s",
413 embedded_status_text ? embedded_status_text : "unspecified",
415 OPENSSL_free(embedded_status_text);
420 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
422 return sk_ASN1_UTF8STRING2text(text, "/", TS_MAX_STATUS_LENGTH);
425 static int ts_check_policy(const ASN1_OBJECT *req_oid,
426 const TS_TST_INFO *tst_info)
428 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
430 if (OBJ_cmp(req_oid, resp_oid) != 0) {
431 ERR_raise(ERR_LIB_TS, TS_R_POLICY_MISMATCH);
438 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
440 unsigned char **imprint, unsigned *imprint_len)
442 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
443 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
445 EVP_MD_CTX *md_ctx = NULL;
446 unsigned char buffer[4096];
452 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
454 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
455 ERR_raise(ERR_LIB_TS, TS_R_UNSUPPORTED_MD_ALGORITHM);
458 length = EVP_MD_size(md);
461 *imprint_len = length;
462 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
463 ERR_raise(ERR_LIB_TS, ERR_R_MALLOC_FAILURE);
467 md_ctx = EVP_MD_CTX_new();
468 if (md_ctx == NULL) {
469 ERR_raise(ERR_LIB_TS, ERR_R_MALLOC_FAILURE);
472 if (!EVP_DigestInit(md_ctx, md))
474 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
475 if (!EVP_DigestUpdate(md_ctx, buffer, length))
478 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
480 EVP_MD_CTX_free(md_ctx);
484 EVP_MD_CTX_free(md_ctx);
485 X509_ALGOR_free(*md_alg);
486 OPENSSL_free(*imprint);
492 static int ts_check_imprints(X509_ALGOR *algor_a,
493 const unsigned char *imprint_a, unsigned len_a,
494 TS_TST_INFO *tst_info)
496 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
497 X509_ALGOR *algor_b = b->hash_algo;
501 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
504 /* The parameter must be NULL in both. */
505 if ((algor_a->parameter
506 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
507 || (algor_b->parameter
508 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
512 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
513 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
516 ERR_raise(ERR_LIB_TS, TS_R_MESSAGE_IMPRINT_MISMATCH);
520 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
522 const ASN1_INTEGER *b = tst_info->nonce;
525 ERR_raise(ERR_LIB_TS, TS_R_NONCE_NOT_RETURNED);
529 /* No error if a nonce is returned without being requested. */
530 if (ASN1_INTEGER_cmp(a, b) != 0) {
531 ERR_raise(ERR_LIB_TS, TS_R_NONCE_MISMATCH);
539 * Check if the specified TSA name matches either the subject or one of the
540 * subject alternative names of the TSA certificate.
542 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
544 STACK_OF(GENERAL_NAME) *gen_names = NULL;
548 if (tsa_name->type == GEN_DIRNAME
549 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
551 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
552 while (gen_names != NULL) {
553 found = ts_find_name(gen_names, tsa_name) >= 0;
557 * Get the next subject alternative name, although there should be no
560 GENERAL_NAMES_free(gen_names);
561 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
563 GENERAL_NAMES_free(gen_names);
568 /* Returns 1 if name is in gen_names, 0 otherwise. */
569 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
572 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
573 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
574 found = GENERAL_NAME_cmp(current, name) == 0;
576 return found ? i - 1 : -1;