2 * Copyright 2006-2020 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 DEFINE_STACK_OF(PKCS7_SIGNER_INFO)
19 DEFINE_STACK_OF(ESS_CERT_ID)
20 DEFINE_STACK_OF(ESS_CERT_ID_V2)
21 DEFINE_STACK_OF(ASN1_UTF8STRING)
23 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
24 X509 *signer, STACK_OF(X509) **chain);
25 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
26 STACK_OF(X509) *chain);
28 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
29 PKCS7 *token, TS_TST_INFO *tst_info);
30 static int ts_check_status_info(TS_RESP *response);
31 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
32 static int ts_check_policy(const ASN1_OBJECT *req_oid,
33 const TS_TST_INFO *tst_info);
34 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
36 unsigned char **imprint, unsigned *imprint_len);
37 static int ts_check_imprints(X509_ALGOR *algor_a,
38 const unsigned char *imprint_a, unsigned len_a,
39 TS_TST_INFO *tst_info);
40 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
41 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
42 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names,
46 * This must be large enough to hold all values in ts_status_text (with
47 * comma separator) or all text fields in ts_failure_info (also with comma).
49 #define TS_STATUS_BUF_SIZE 256
52 * Local mapping between response codes and descriptions.
54 static const char *ts_status_text[] = {
60 "revocationNotification"
63 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
68 } ts_failure_info[] = {
69 {TS_INFO_BAD_ALG, "badAlg"},
70 {TS_INFO_BAD_REQUEST, "badRequest"},
71 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
72 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
73 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
74 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
75 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
76 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
81 * This function carries out the following tasks:
82 * - Checks if there is one and only one signer.
83 * - Search for the signing certificate in 'certs' and in the response.
84 * - Check the extended key usage and key usage fields of the signer
85 * certificate (done by the path validation).
86 * - Build and validate the certificate path.
87 * - Check if the certificate path meets the requirements of the
88 * SigningCertificate ESS signed attribute.
89 * - Verify the signature value.
90 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
92 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
93 X509_STORE *store, X509 **signer_out)
95 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
96 PKCS7_SIGNER_INFO *si;
97 STACK_OF(X509) *signers = NULL;
99 STACK_OF(X509) *chain = NULL;
101 int i, j = 0, ret = 0;
104 /* Some sanity checks first. */
106 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
109 if (!PKCS7_type_is_signed(token)) {
110 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
113 sinfos = PKCS7_get_signer_info(token);
114 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
115 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
118 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
119 if (PKCS7_get_detached(token)) {
120 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
125 * Get hold of the signer certificate, search only internal certificates
126 * if it was requested.
128 signers = PKCS7_get0_signers(token, certs, 0);
129 if (!signers || sk_X509_num(signers) != 1)
131 signer = sk_X509_value(signers, 0);
133 if (!ts_verify_cert(store, certs, signer, &chain))
135 if (!ts_check_signing_certs(si, chain))
137 p7bio = PKCS7_dataInit(token, NULL);
139 /* We now have to 'read' from p7bio to calculate digests etc. */
140 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
143 j = PKCS7_signatureVerify(p7bio, token, si, signer);
145 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
150 *signer_out = signer;
157 sk_X509_pop_free(chain, X509_free);
158 sk_X509_free(signers);
164 * The certificate chain is returned in chain. Caller is responsible for
165 * freeing the vector.
167 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
168 X509 *signer, STACK_OF(X509) **chain)
170 X509_STORE_CTX *cert_ctx = NULL;
175 cert_ctx = X509_STORE_CTX_new();
176 if (cert_ctx == NULL) {
177 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
180 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
182 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
183 i = X509_verify_cert(cert_ctx);
185 int j = X509_STORE_CTX_get_error(cert_ctx);
186 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
187 ERR_add_error_data(2, "Verify error:",
188 X509_verify_cert_error_string(j));
191 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
199 X509_STORE_CTX_free(cert_ctx);
203 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
204 STACK_OF(X509) *chain)
206 ESS_SIGNING_CERT *ss = ESS_SIGNING_CERT_get(si);
207 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
208 ESS_SIGNING_CERT_V2 *ssv2 = ESS_SIGNING_CERT_V2_get(si);
209 STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
215 cert_ids = ss->cert_ids;
216 cert = sk_X509_value(chain, 0);
217 if (ess_find_cert(cert_ids, cert) != 0)
221 * Check the other certificates of the chain if there are more than one
222 * certificate ids in cert_ids.
224 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
225 for (i = 1; i < sk_X509_num(chain); ++i) {
226 cert = sk_X509_value(chain, i);
227 if (ess_find_cert(cert_ids, cert) < 0)
231 } else if (ssv2 != NULL) {
232 cert_ids_v2 = ssv2->cert_ids;
233 cert = sk_X509_value(chain, 0);
234 if (ess_find_cert_v2(cert_ids_v2, cert) != 0)
238 * Check the other certificates of the chain if there are more than one
239 * certificate ids in cert_ids.
241 if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
242 for (i = 1; i < sk_X509_num(chain); ++i) {
243 cert = sk_X509_value(chain, i);
244 if (ess_find_cert_v2(cert_ids_v2, cert) < 0)
255 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
256 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
257 ESS_SIGNING_CERT_free(ss);
258 ESS_SIGNING_CERT_V2_free(ssv2);
263 * Verifies whether 'response' contains a valid response with regards
264 * to the settings of the context:
265 * - Gives an error message if the TS_TST_INFO is not present.
266 * - Calls _TS_RESP_verify_token to verify the token content.
268 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
270 PKCS7 *token = response->token;
271 TS_TST_INFO *tst_info = response->tst_info;
274 if (!ts_check_status_info(response))
276 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
285 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
286 * calls the internal int_TS_RESP_verify_token function for verifying it.
288 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
290 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
293 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
294 TS_TST_INFO_free(tst_info);
300 * Verifies whether the 'token' contains a valid time stamp token
301 * with regards to the settings of the context. Only those checks are
302 * carried out that are specified in the context:
303 * - Verifies the signature of the TS_TST_INFO.
304 * - Checks the version number of the response.
305 * - Check if the requested and returned policies math.
306 * - Check if the message imprints are the same.
307 * - Check if the nonces are the same.
308 * - Check if the TSA name matches the signer.
309 * - Check if the TSA name is the expected TSA.
311 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
312 PKCS7 *token, TS_TST_INFO *tst_info)
315 GENERAL_NAME *tsa_name = tst_info->tsa;
316 X509_ALGOR *md_alg = NULL;
317 unsigned char *imprint = NULL;
318 unsigned imprint_len = 0;
320 int flags = ctx->flags;
322 /* Some options require us to also check the signature */
323 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
324 || (flags & TS_VFY_TSA_NAME)) {
325 flags |= TS_VFY_SIGNATURE;
328 if ((flags & TS_VFY_SIGNATURE)
329 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
331 if ((flags & TS_VFY_VERSION)
332 && TS_TST_INFO_get_version(tst_info) != 1) {
333 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
336 if ((flags & TS_VFY_POLICY)
337 && !ts_check_policy(ctx->policy, tst_info))
339 if ((flags & TS_VFY_IMPRINT)
340 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
343 if ((flags & TS_VFY_DATA)
344 && (!ts_compute_imprint(ctx->data, tst_info,
345 &md_alg, &imprint, &imprint_len)
346 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
348 if ((flags & TS_VFY_NONCE)
349 && !ts_check_nonces(ctx->nonce, tst_info))
351 if ((flags & TS_VFY_SIGNER)
352 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
353 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
356 if ((flags & TS_VFY_TSA_NAME)
357 && !ts_check_signer_name(ctx->tsa_name, signer)) {
358 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
365 X509_ALGOR_free(md_alg);
366 OPENSSL_free(imprint);
370 static int ts_check_status_info(TS_RESP *response)
372 TS_STATUS_INFO *info = response->status_info;
373 long status = ASN1_INTEGER_get(info->status);
374 const char *status_text = NULL;
375 char *embedded_status_text = NULL;
376 char failure_text[TS_STATUS_BUF_SIZE] = "";
378 if (status == 0 || status == 1)
381 /* There was an error, get the description in status_text. */
382 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
383 status_text = ts_status_text[status];
385 status_text = "unknown code";
387 if (sk_ASN1_UTF8STRING_num(info->text) > 0
388 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
391 /* Fill in failure_text with the failure information. */
392 if (info->failure_info) {
395 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
396 if (ASN1_BIT_STRING_get_bit(info->failure_info,
397 ts_failure_info[i].code)) {
399 strcat(failure_text, ",");
402 strcat(failure_text, ts_failure_info[i].text);
406 if (failure_text[0] == '\0')
407 strcpy(failure_text, "unspecified");
409 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
410 ERR_add_error_data(6,
411 "status code: ", status_text,
412 ", status text: ", embedded_status_text ?
413 embedded_status_text : "unspecified",
414 ", failure codes: ", failure_text);
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 TSerr(TS_F_TS_CHECK_POLICY, 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 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
458 length = EVP_MD_size(md);
461 *imprint_len = length;
462 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
463 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
467 md_ctx = EVP_MD_CTX_new();
468 if (md_ctx == NULL) {
469 TSerr(TS_F_TS_COMPUTE_IMPRINT, 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 TSerr(TS_F_TS_CHECK_IMPRINTS, 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 TSerr(TS_F_TS_CHECK_NONCES, 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 TSerr(TS_F_TS_CHECK_NONCES, 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;