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,
40 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert);
41 static ESS_SIGNING_CERT_V2 *ess_get_signing_cert_v2(PKCS7_SIGNER_INFO *si);
44 * This must be large enough to hold all values in ts_status_text (with
45 * comma separator) or all text fields in ts_failure_info (also with comma).
47 #define TS_STATUS_BUF_SIZE 256
50 * Local mapping between response codes and descriptions.
52 static const char *ts_status_text[] = {
58 "revocationNotification"
61 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
66 } ts_failure_info[] = {
67 {TS_INFO_BAD_ALG, "badAlg"},
68 {TS_INFO_BAD_REQUEST, "badRequest"},
69 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
70 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
71 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
72 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
73 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
74 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
79 * This function carries out the following tasks:
80 * - Checks if there is one and only one signer.
81 * - Search for the signing certificate in 'certs' and in the response.
82 * - Check the extended key usage and key usage fields of the signer
83 * certificate (done by the path validation).
84 * - Build and validate the certificate path.
85 * - Check if the certificate path meets the requirements of the
86 * SigningCertificate ESS signed attribute.
87 * - Verify the signature value.
88 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
90 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
91 X509_STORE *store, X509 **signer_out)
93 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
94 PKCS7_SIGNER_INFO *si;
95 STACK_OF(X509) *signers = NULL;
97 STACK_OF(X509) *chain = NULL;
99 int i, j = 0, ret = 0;
102 /* Some sanity checks first. */
104 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
107 if (!PKCS7_type_is_signed(token)) {
108 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
111 sinfos = PKCS7_get_signer_info(token);
112 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
113 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
116 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
117 if (PKCS7_get_detached(token)) {
118 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
123 * Get hold of the signer certificate, search only internal certificates
124 * if it was requested.
126 signers = PKCS7_get0_signers(token, certs, 0);
127 if (!signers || sk_X509_num(signers) != 1)
129 signer = sk_X509_value(signers, 0);
131 if (!ts_verify_cert(store, certs, signer, &chain))
133 if (!ts_check_signing_certs(si, chain))
135 p7bio = PKCS7_dataInit(token, NULL);
137 /* We now have to 'read' from p7bio to calculate digests etc. */
138 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
141 j = PKCS7_signatureVerify(p7bio, token, si, signer);
143 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
148 *signer_out = signer;
155 sk_X509_pop_free(chain, X509_free);
156 sk_X509_free(signers);
162 * The certificate chain is returned in chain. Caller is responsible for
163 * freeing the vector.
165 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
166 X509 *signer, STACK_OF(X509) **chain)
168 X509_STORE_CTX *cert_ctx = NULL;
173 cert_ctx = X509_STORE_CTX_new();
174 if (cert_ctx == NULL) {
175 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
178 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
180 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
181 i = X509_verify_cert(cert_ctx);
183 int j = X509_STORE_CTX_get_error(cert_ctx);
184 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
185 ERR_add_error_data(2, "Verify error:",
186 X509_verify_cert_error_string(j));
189 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
197 X509_STORE_CTX_free(cert_ctx);
201 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
202 STACK_OF(X509) *chain)
204 ESS_SIGNING_CERT *ss = ess_get_signing_cert(si);
205 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
206 ESS_SIGNING_CERT_V2 *ssv2 = ess_get_signing_cert_v2(si);
207 STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
213 cert_ids = ss->cert_ids;
214 cert = sk_X509_value(chain, 0);
215 if (ts_find_cert(cert_ids, cert) != 0)
219 * Check the other certificates of the chain if there are more than one
220 * certificate ids in cert_ids.
222 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
223 for (i = 1; i < sk_X509_num(chain); ++i) {
224 cert = sk_X509_value(chain, i);
225 if (ts_find_cert(cert_ids, cert) < 0)
229 } else if (ssv2 != NULL) {
230 cert_ids_v2 = ssv2->cert_ids;
231 cert = sk_X509_value(chain, 0);
232 if (ts_find_cert_v2(cert_ids_v2, cert) != 0)
236 * Check the other certificates of the chain if there are more than one
237 * certificate ids in cert_ids.
239 if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
240 for (i = 1; i < sk_X509_num(chain); ++i) {
241 cert = sk_X509_value(chain, i);
242 if (ts_find_cert_v2(cert_ids_v2, cert) < 0)
253 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
254 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
255 ESS_SIGNING_CERT_free(ss);
256 ESS_SIGNING_CERT_V2_free(ssv2);
260 static ESS_SIGNING_CERT *ess_get_signing_cert(PKCS7_SIGNER_INFO *si)
263 const unsigned char *p;
264 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
267 p = attr->value.sequence->data;
268 return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
271 static ESS_SIGNING_CERT_V2 *ess_get_signing_cert_v2(PKCS7_SIGNER_INFO *si)
274 const unsigned char *p;
276 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificateV2);
279 p = attr->value.sequence->data;
280 return d2i_ESS_SIGNING_CERT_V2(NULL, &p, attr->value.sequence->length);
283 /* Returns < 0 if certificate is not found, certificate index otherwise. */
284 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
287 unsigned char cert_sha1[SHA_DIGEST_LENGTH];
289 if (!cert_ids || !cert)
292 X509_digest(cert, EVP_sha1(), cert_sha1, NULL);
294 /* Recompute SHA1 hash of certificate if necessary (side effect). */
295 X509_check_purpose(cert, -1, 0);
297 /* Look for cert in the cert_ids vector. */
298 for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
299 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
301 if (cid->hash->length == SHA_DIGEST_LENGTH
302 && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
303 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
304 if (!is || !ts_issuer_serial_cmp(is, cert))
312 /* Returns < 0 if certificate is not found, certificate index otherwise. */
313 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert)
316 unsigned char cert_digest[EVP_MAX_MD_SIZE];
319 /* Look for cert in the cert_ids vector. */
320 for (i = 0; i < sk_ESS_CERT_ID_V2_num(cert_ids); ++i) {
321 ESS_CERT_ID_V2 *cid = sk_ESS_CERT_ID_V2_value(cert_ids, i);
324 if (cid->hash_alg != NULL)
325 md = EVP_get_digestbyobj(cid->hash_alg->algorithm);
329 X509_digest(cert, md, cert_digest, &len);
330 if (cid->hash->length != (int)len)
333 if (memcmp(cid->hash->data, cert_digest, cid->hash->length) == 0) {
334 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
336 if (is == NULL || !ts_issuer_serial_cmp(is, cert))
344 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
346 GENERAL_NAME *issuer;
348 if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
351 issuer = sk_GENERAL_NAME_value(is->issuer, 0);
352 if (issuer->type != GEN_DIRNAME
353 || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
356 if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
363 * Verifies whether 'response' contains a valid response with regards
364 * to the settings of the context:
365 * - Gives an error message if the TS_TST_INFO is not present.
366 * - Calls _TS_RESP_verify_token to verify the token content.
368 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
370 PKCS7 *token = response->token;
371 TS_TST_INFO *tst_info = response->tst_info;
374 if (!ts_check_status_info(response))
376 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
385 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
386 * calls the internal int_TS_RESP_verify_token function for verifying it.
388 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
390 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
393 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
394 TS_TST_INFO_free(tst_info);
400 * Verifies whether the 'token' contains a valid time stamp token
401 * with regards to the settings of the context. Only those checks are
402 * carried out that are specified in the context:
403 * - Verifies the signature of the TS_TST_INFO.
404 * - Checks the version number of the response.
405 * - Check if the requested and returned policies math.
406 * - Check if the message imprints are the same.
407 * - Check if the nonces are the same.
408 * - Check if the TSA name matches the signer.
409 * - Check if the TSA name is the expected TSA.
411 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
412 PKCS7 *token, TS_TST_INFO *tst_info)
415 GENERAL_NAME *tsa_name = tst_info->tsa;
416 X509_ALGOR *md_alg = NULL;
417 unsigned char *imprint = NULL;
418 unsigned imprint_len = 0;
420 int flags = ctx->flags;
422 /* Some options require us to also check the signature */
423 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
424 || (flags & TS_VFY_TSA_NAME)) {
425 flags |= TS_VFY_SIGNATURE;
428 if ((flags & TS_VFY_SIGNATURE)
429 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
431 if ((flags & TS_VFY_VERSION)
432 && TS_TST_INFO_get_version(tst_info) != 1) {
433 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
436 if ((flags & TS_VFY_POLICY)
437 && !ts_check_policy(ctx->policy, tst_info))
439 if ((flags & TS_VFY_IMPRINT)
440 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
443 if ((flags & TS_VFY_DATA)
444 && (!ts_compute_imprint(ctx->data, tst_info,
445 &md_alg, &imprint, &imprint_len)
446 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
448 if ((flags & TS_VFY_NONCE)
449 && !ts_check_nonces(ctx->nonce, tst_info))
451 if ((flags & TS_VFY_SIGNER)
452 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
453 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
456 if ((flags & TS_VFY_TSA_NAME)
457 && !ts_check_signer_name(ctx->tsa_name, signer)) {
458 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
465 X509_ALGOR_free(md_alg);
466 OPENSSL_free(imprint);
470 static int ts_check_status_info(TS_RESP *response)
472 TS_STATUS_INFO *info = response->status_info;
473 long status = ASN1_INTEGER_get(info->status);
474 const char *status_text = NULL;
475 char *embedded_status_text = NULL;
476 char failure_text[TS_STATUS_BUF_SIZE] = "";
478 if (status == 0 || status == 1)
481 /* There was an error, get the description in status_text. */
482 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
483 status_text = ts_status_text[status];
485 status_text = "unknown code";
487 if (sk_ASN1_UTF8STRING_num(info->text) > 0
488 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
491 /* Fill in failure_text with the failure information. */
492 if (info->failure_info) {
495 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
496 if (ASN1_BIT_STRING_get_bit(info->failure_info,
497 ts_failure_info[i].code)) {
499 strcat(failure_text, ",");
502 strcat(failure_text, ts_failure_info[i].text);
506 if (failure_text[0] == '\0')
507 strcpy(failure_text, "unspecified");
509 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
510 ERR_add_error_data(6,
511 "status code: ", status_text,
512 ", status text: ", embedded_status_text ?
513 embedded_status_text : "unspecified",
514 ", failure codes: ", failure_text);
515 OPENSSL_free(embedded_status_text);
520 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
527 for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) {
528 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
529 if (ASN1_STRING_length(current) > TS_MAX_STATUS_LENGTH - length - 1)
531 length += ASN1_STRING_length(current);
532 length += 1; /* separator character */
534 if ((result = OPENSSL_malloc(length)) == NULL) {
535 TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE);
539 for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i) {
540 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
541 length = ASN1_STRING_length(current);
544 strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
552 static int ts_check_policy(const ASN1_OBJECT *req_oid,
553 const TS_TST_INFO *tst_info)
555 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
557 if (OBJ_cmp(req_oid, resp_oid) != 0) {
558 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
565 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
567 unsigned char **imprint, unsigned *imprint_len)
569 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
570 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
572 EVP_MD_CTX *md_ctx = NULL;
573 unsigned char buffer[4096];
579 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
581 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
582 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
585 length = EVP_MD_size(md);
588 *imprint_len = length;
589 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
590 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
594 md_ctx = EVP_MD_CTX_new();
595 if (md_ctx == NULL) {
596 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
599 if (!EVP_DigestInit(md_ctx, md))
601 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
602 if (!EVP_DigestUpdate(md_ctx, buffer, length))
605 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
607 EVP_MD_CTX_free(md_ctx);
611 EVP_MD_CTX_free(md_ctx);
612 X509_ALGOR_free(*md_alg);
613 OPENSSL_free(*imprint);
619 static int ts_check_imprints(X509_ALGOR *algor_a,
620 const unsigned char *imprint_a, unsigned len_a,
621 TS_TST_INFO *tst_info)
623 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
624 X509_ALGOR *algor_b = b->hash_algo;
628 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
631 /* The parameter must be NULL in both. */
632 if ((algor_a->parameter
633 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
634 || (algor_b->parameter
635 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
639 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
640 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
643 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
647 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
649 const ASN1_INTEGER *b = tst_info->nonce;
652 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
656 /* No error if a nonce is returned without being requested. */
657 if (ASN1_INTEGER_cmp(a, b) != 0) {
658 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
666 * Check if the specified TSA name matches either the subject or one of the
667 * subject alternative names of the TSA certificate.
669 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
671 STACK_OF(GENERAL_NAME) *gen_names = NULL;
675 if (tsa_name->type == GEN_DIRNAME
676 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
678 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
679 while (gen_names != NULL) {
680 found = ts_find_name(gen_names, tsa_name) >= 0;
684 * Get the next subject alternative name, although there should be no
687 GENERAL_NAMES_free(gen_names);
688 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
690 GENERAL_NAMES_free(gen_names);
695 /* Returns 1 if name is in gen_names, 0 otherwise. */
696 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
699 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
700 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
701 found = GENERAL_NAME_cmp(current, name) == 0;
703 return found ? i - 1 : -1;