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)
20 DEFINE_STACK_OF(ESS_CERT_ID)
21 DEFINE_STACK_OF(ESS_CERT_ID_V2)
22 DEFINE_STACK_OF(ASN1_UTF8STRING)
23 DEFINE_STACK_OF(GENERAL_NAME)
25 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
26 X509 *signer, STACK_OF(X509) **chain);
27 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
28 STACK_OF(X509) *chain);
29 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert);
30 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert);
31 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
32 PKCS7 *token, TS_TST_INFO *tst_info);
33 static int ts_check_status_info(TS_RESP *response);
34 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text);
35 static int ts_check_policy(const ASN1_OBJECT *req_oid,
36 const TS_TST_INFO *tst_info);
37 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
39 unsigned char **imprint, unsigned *imprint_len);
40 static int ts_check_imprints(X509_ALGOR *algor_a,
41 const unsigned char *imprint_a, unsigned len_a,
42 TS_TST_INFO *tst_info);
43 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info);
44 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer);
45 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names,
47 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert);
50 * This must be large enough to hold all values in ts_status_text (with
51 * comma separator) or all text fields in ts_failure_info (also with comma).
53 #define TS_STATUS_BUF_SIZE 256
56 * Local mapping between response codes and descriptions.
58 static const char *ts_status_text[] = {
64 "revocationNotification"
67 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
72 } ts_failure_info[] = {
73 {TS_INFO_BAD_ALG, "badAlg"},
74 {TS_INFO_BAD_REQUEST, "badRequest"},
75 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
76 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
77 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
78 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
79 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
80 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
85 * This function carries out the following tasks:
86 * - Checks if there is one and only one signer.
87 * - Search for the signing certificate in 'certs' and in the response.
88 * - Check the extended key usage and key usage fields of the signer
89 * certificate (done by the path validation).
90 * - Build and validate the certificate path.
91 * - Check if the certificate path meets the requirements of the
92 * SigningCertificate ESS signed attribute.
93 * - Verify the signature value.
94 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
96 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
97 X509_STORE *store, X509 **signer_out)
99 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
100 PKCS7_SIGNER_INFO *si;
101 STACK_OF(X509) *signers = NULL;
103 STACK_OF(X509) *chain = NULL;
105 int i, j = 0, ret = 0;
108 /* Some sanity checks first. */
110 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
113 if (!PKCS7_type_is_signed(token)) {
114 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
117 sinfos = PKCS7_get_signer_info(token);
118 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
119 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
122 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
123 if (PKCS7_get_detached(token)) {
124 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
129 * Get hold of the signer certificate, search only internal certificates
130 * if it was requested.
132 signers = PKCS7_get0_signers(token, certs, 0);
133 if (!signers || sk_X509_num(signers) != 1)
135 signer = sk_X509_value(signers, 0);
137 if (!ts_verify_cert(store, certs, signer, &chain))
139 if (!ts_check_signing_certs(si, chain))
141 p7bio = PKCS7_dataInit(token, NULL);
143 /* We now have to 'read' from p7bio to calculate digests etc. */
144 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
147 j = PKCS7_signatureVerify(p7bio, token, si, signer);
149 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
154 *signer_out = signer;
161 sk_X509_pop_free(chain, X509_free);
162 sk_X509_free(signers);
168 * The certificate chain is returned in chain. Caller is responsible for
169 * freeing the vector.
171 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
172 X509 *signer, STACK_OF(X509) **chain)
174 X509_STORE_CTX *cert_ctx = NULL;
179 cert_ctx = X509_STORE_CTX_new();
180 if (cert_ctx == NULL) {
181 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
184 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
186 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
187 i = X509_verify_cert(cert_ctx);
189 int j = X509_STORE_CTX_get_error(cert_ctx);
190 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
191 ERR_add_error_data(2, "Verify error:",
192 X509_verify_cert_error_string(j));
195 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
203 X509_STORE_CTX_free(cert_ctx);
207 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
208 STACK_OF(X509) *chain)
210 ESS_SIGNING_CERT *ss = ESS_SIGNING_CERT_get(si);
211 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
212 ESS_SIGNING_CERT_V2 *ssv2 = ESS_SIGNING_CERT_V2_get(si);
213 STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
219 cert_ids = ss->cert_ids;
220 cert = sk_X509_value(chain, 0);
221 if (ts_find_cert(cert_ids, cert) != 0)
225 * Check the other certificates of the chain if there are more than one
226 * certificate ids in cert_ids.
228 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
229 for (i = 1; i < sk_X509_num(chain); ++i) {
230 cert = sk_X509_value(chain, i);
231 if (ts_find_cert(cert_ids, cert) < 0)
235 } else if (ssv2 != NULL) {
236 cert_ids_v2 = ssv2->cert_ids;
237 cert = sk_X509_value(chain, 0);
238 if (ts_find_cert_v2(cert_ids_v2, cert) != 0)
242 * Check the other certificates of the chain if there are more than one
243 * certificate ids in cert_ids.
245 if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
246 for (i = 1; i < sk_X509_num(chain); ++i) {
247 cert = sk_X509_value(chain, i);
248 if (ts_find_cert_v2(cert_ids_v2, cert) < 0)
259 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
260 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
261 ESS_SIGNING_CERT_free(ss);
262 ESS_SIGNING_CERT_V2_free(ssv2);
266 /* Returns < 0 if certificate is not found, certificate index otherwise. */
267 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
270 unsigned char cert_sha1[SHA_DIGEST_LENGTH];
272 if (!cert_ids || !cert)
275 /* Recompute SHA1 hash of certificate if necessary (side effect). */
276 X509_check_purpose(cert, -1, 0);
278 if (!X509_digest(cert, EVP_sha1(), cert_sha1, NULL))
281 /* Look for cert in the cert_ids vector. */
282 for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
283 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
285 if (cid->hash->length == SHA_DIGEST_LENGTH
286 && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
287 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
288 if (!is || !ts_issuer_serial_cmp(is, cert))
296 /* Returns < 0 if certificate is not found, certificate index otherwise. */
297 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert)
300 unsigned char cert_digest[EVP_MAX_MD_SIZE];
303 /* Look for cert in the cert_ids vector. */
304 for (i = 0; i < sk_ESS_CERT_ID_V2_num(cert_ids); ++i) {
305 ESS_CERT_ID_V2 *cid = sk_ESS_CERT_ID_V2_value(cert_ids, i);
308 if (cid->hash_alg != NULL)
309 md = EVP_get_digestbyobj(cid->hash_alg->algorithm);
313 if (!X509_digest(cert, md, cert_digest, &len))
315 if (cid->hash->length != (int)len)
318 if (memcmp(cid->hash->data, cert_digest, cid->hash->length) == 0) {
319 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
321 if (is == NULL || !ts_issuer_serial_cmp(is, cert))
329 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
331 GENERAL_NAME *issuer;
333 if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
336 issuer = sk_GENERAL_NAME_value(is->issuer, 0);
337 if (issuer->type != GEN_DIRNAME
338 || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
341 if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
348 * Verifies whether 'response' contains a valid response with regards
349 * to the settings of the context:
350 * - Gives an error message if the TS_TST_INFO is not present.
351 * - Calls _TS_RESP_verify_token to verify the token content.
353 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
355 PKCS7 *token = response->token;
356 TS_TST_INFO *tst_info = response->tst_info;
359 if (!ts_check_status_info(response))
361 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
370 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
371 * calls the internal int_TS_RESP_verify_token function for verifying it.
373 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
375 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
378 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
379 TS_TST_INFO_free(tst_info);
385 * Verifies whether the 'token' contains a valid time stamp token
386 * with regards to the settings of the context. Only those checks are
387 * carried out that are specified in the context:
388 * - Verifies the signature of the TS_TST_INFO.
389 * - Checks the version number of the response.
390 * - Check if the requested and returned policies math.
391 * - Check if the message imprints are the same.
392 * - Check if the nonces are the same.
393 * - Check if the TSA name matches the signer.
394 * - Check if the TSA name is the expected TSA.
396 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
397 PKCS7 *token, TS_TST_INFO *tst_info)
400 GENERAL_NAME *tsa_name = tst_info->tsa;
401 X509_ALGOR *md_alg = NULL;
402 unsigned char *imprint = NULL;
403 unsigned imprint_len = 0;
405 int flags = ctx->flags;
407 /* Some options require us to also check the signature */
408 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
409 || (flags & TS_VFY_TSA_NAME)) {
410 flags |= TS_VFY_SIGNATURE;
413 if ((flags & TS_VFY_SIGNATURE)
414 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
416 if ((flags & TS_VFY_VERSION)
417 && TS_TST_INFO_get_version(tst_info) != 1) {
418 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
421 if ((flags & TS_VFY_POLICY)
422 && !ts_check_policy(ctx->policy, tst_info))
424 if ((flags & TS_VFY_IMPRINT)
425 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
428 if ((flags & TS_VFY_DATA)
429 && (!ts_compute_imprint(ctx->data, tst_info,
430 &md_alg, &imprint, &imprint_len)
431 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
433 if ((flags & TS_VFY_NONCE)
434 && !ts_check_nonces(ctx->nonce, tst_info))
436 if ((flags & TS_VFY_SIGNER)
437 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
438 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
441 if ((flags & TS_VFY_TSA_NAME)
442 && !ts_check_signer_name(ctx->tsa_name, signer)) {
443 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
450 X509_ALGOR_free(md_alg);
451 OPENSSL_free(imprint);
455 static int ts_check_status_info(TS_RESP *response)
457 TS_STATUS_INFO *info = response->status_info;
458 long status = ASN1_INTEGER_get(info->status);
459 const char *status_text = NULL;
460 char *embedded_status_text = NULL;
461 char failure_text[TS_STATUS_BUF_SIZE] = "";
463 if (status == 0 || status == 1)
466 /* There was an error, get the description in status_text. */
467 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
468 status_text = ts_status_text[status];
470 status_text = "unknown code";
472 if (sk_ASN1_UTF8STRING_num(info->text) > 0
473 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
476 /* Fill in failure_text with the failure information. */
477 if (info->failure_info) {
480 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
481 if (ASN1_BIT_STRING_get_bit(info->failure_info,
482 ts_failure_info[i].code)) {
484 strcat(failure_text, ",");
487 strcat(failure_text, ts_failure_info[i].text);
491 if (failure_text[0] == '\0')
492 strcpy(failure_text, "unspecified");
494 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
495 ERR_add_error_data(6,
496 "status code: ", status_text,
497 ", status text: ", embedded_status_text ?
498 embedded_status_text : "unspecified",
499 ", failure codes: ", failure_text);
500 OPENSSL_free(embedded_status_text);
505 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
507 return sk_ASN1_UTF8STRING2text(text, "/", TS_MAX_STATUS_LENGTH);
510 static int ts_check_policy(const ASN1_OBJECT *req_oid,
511 const TS_TST_INFO *tst_info)
513 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
515 if (OBJ_cmp(req_oid, resp_oid) != 0) {
516 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
523 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
525 unsigned char **imprint, unsigned *imprint_len)
527 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
528 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
530 EVP_MD_CTX *md_ctx = NULL;
531 unsigned char buffer[4096];
537 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
539 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
540 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
543 length = EVP_MD_size(md);
546 *imprint_len = length;
547 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
548 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
552 md_ctx = EVP_MD_CTX_new();
553 if (md_ctx == NULL) {
554 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
557 if (!EVP_DigestInit(md_ctx, md))
559 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
560 if (!EVP_DigestUpdate(md_ctx, buffer, length))
563 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
565 EVP_MD_CTX_free(md_ctx);
569 EVP_MD_CTX_free(md_ctx);
570 X509_ALGOR_free(*md_alg);
571 OPENSSL_free(*imprint);
577 static int ts_check_imprints(X509_ALGOR *algor_a,
578 const unsigned char *imprint_a, unsigned len_a,
579 TS_TST_INFO *tst_info)
581 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
582 X509_ALGOR *algor_b = b->hash_algo;
586 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
589 /* The parameter must be NULL in both. */
590 if ((algor_a->parameter
591 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
592 || (algor_b->parameter
593 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
597 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
598 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
601 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
605 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
607 const ASN1_INTEGER *b = tst_info->nonce;
610 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
614 /* No error if a nonce is returned without being requested. */
615 if (ASN1_INTEGER_cmp(a, b) != 0) {
616 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
624 * Check if the specified TSA name matches either the subject or one of the
625 * subject alternative names of the TSA certificate.
627 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
629 STACK_OF(GENERAL_NAME) *gen_names = NULL;
633 if (tsa_name->type == GEN_DIRNAME
634 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
636 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
637 while (gen_names != NULL) {
638 found = ts_find_name(gen_names, tsa_name) >= 0;
642 * Get the next subject alternative name, although there should be no
645 GENERAL_NAMES_free(gen_names);
646 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
648 GENERAL_NAMES_free(gen_names);
653 /* Returns 1 if name is in gen_names, 0 otherwise. */
654 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
657 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
658 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
659 found = GENERAL_NAME_cmp(current, name) == 0;
661 return found ? i - 1 : -1;