2 * Copyright 2006-2019 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 "internal/ess_int.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);
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);
43 * This must be large enough to hold all values in ts_status_text (with
44 * comma separator) or all text fields in ts_failure_info (also with comma).
46 #define TS_STATUS_BUF_SIZE 256
49 * Local mapping between response codes and descriptions.
51 static const char *ts_status_text[] = {
57 "revocationNotification"
60 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
65 } ts_failure_info[] = {
66 {TS_INFO_BAD_ALG, "badAlg"},
67 {TS_INFO_BAD_REQUEST, "badRequest"},
68 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
69 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
70 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
71 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
72 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
73 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
78 * This function carries out the following tasks:
79 * - Checks if there is one and only one signer.
80 * - Search for the signing certificate in 'certs' and in the response.
81 * - Check the extended key usage and key usage fields of the signer
82 * certificate (done by the path validation).
83 * - Build and validate the certificate path.
84 * - Check if the certificate path meets the requirements of the
85 * SigningCertificate ESS signed attribute.
86 * - Verify the signature value.
87 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
89 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
90 X509_STORE *store, X509 **signer_out)
92 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
93 PKCS7_SIGNER_INFO *si;
94 STACK_OF(X509) *signers = NULL;
96 STACK_OF(X509) *chain = NULL;
98 int i, j = 0, ret = 0;
101 /* Some sanity checks first. */
103 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER);
106 if (!PKCS7_type_is_signed(token)) {
107 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE);
110 sinfos = PKCS7_get_signer_info(token);
111 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
112 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER);
115 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
116 if (PKCS7_get_detached(token)) {
117 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT);
122 * Get hold of the signer certificate, search only internal certificates
123 * if it was requested.
125 signers = PKCS7_get0_signers(token, certs, 0);
126 if (!signers || sk_X509_num(signers) != 1)
128 signer = sk_X509_value(signers, 0);
130 if (!ts_verify_cert(store, certs, signer, &chain))
132 if (!ts_check_signing_certs(si, chain))
134 p7bio = PKCS7_dataInit(token, NULL);
136 /* We now have to 'read' from p7bio to calculate digests etc. */
137 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
140 j = PKCS7_signatureVerify(p7bio, token, si, signer);
142 TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE);
147 *signer_out = signer;
154 sk_X509_pop_free(chain, X509_free);
155 sk_X509_free(signers);
161 * The certificate chain is returned in chain. Caller is responsible for
162 * freeing the vector.
164 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
165 X509 *signer, STACK_OF(X509) **chain)
167 X509_STORE_CTX *cert_ctx = NULL;
172 cert_ctx = X509_STORE_CTX_new();
173 if (cert_ctx == NULL) {
174 TSerr(TS_F_TS_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
177 if (!X509_STORE_CTX_init(cert_ctx, store, signer, untrusted))
179 X509_STORE_CTX_set_purpose(cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN);
180 i = X509_verify_cert(cert_ctx);
182 int j = X509_STORE_CTX_get_error(cert_ctx);
183 TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR);
184 ERR_add_error_data(2, "Verify error:",
185 X509_verify_cert_error_string(j));
188 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
196 X509_STORE_CTX_free(cert_ctx);
200 static int ts_check_signing_certs(PKCS7_SIGNER_INFO *si,
201 STACK_OF(X509) *chain)
203 ESS_SIGNING_CERT *ss = ESS_SIGNING_CERT_get(si);
204 STACK_OF(ESS_CERT_ID) *cert_ids = NULL;
205 ESS_SIGNING_CERT_V2 *ssv2 = ESS_SIGNING_CERT_V2_get(si);
206 STACK_OF(ESS_CERT_ID_V2) *cert_ids_v2 = NULL;
212 cert_ids = ss->cert_ids;
213 cert = sk_X509_value(chain, 0);
214 if (ts_find_cert(cert_ids, cert) != 0)
218 * Check the other certificates of the chain if there are more than one
219 * certificate ids in cert_ids.
221 if (sk_ESS_CERT_ID_num(cert_ids) > 1) {
222 for (i = 1; i < sk_X509_num(chain); ++i) {
223 cert = sk_X509_value(chain, i);
224 if (ts_find_cert(cert_ids, cert) < 0)
228 } else if (ssv2 != NULL) {
229 cert_ids_v2 = ssv2->cert_ids;
230 cert = sk_X509_value(chain, 0);
231 if (ts_find_cert_v2(cert_ids_v2, cert) != 0)
235 * Check the other certificates of the chain if there are more than one
236 * certificate ids in cert_ids.
238 if (sk_ESS_CERT_ID_V2_num(cert_ids_v2) > 1) {
239 for (i = 1; i < sk_X509_num(chain); ++i) {
240 cert = sk_X509_value(chain, i);
241 if (ts_find_cert_v2(cert_ids_v2, cert) < 0)
252 TSerr(TS_F_TS_CHECK_SIGNING_CERTS,
253 TS_R_ESS_SIGNING_CERTIFICATE_ERROR);
254 ESS_SIGNING_CERT_free(ss);
255 ESS_SIGNING_CERT_V2_free(ssv2);
259 /* Returns < 0 if certificate is not found, certificate index otherwise. */
260 static int ts_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert)
263 unsigned char cert_sha1[SHA_DIGEST_LENGTH];
265 if (!cert_ids || !cert)
268 X509_digest(cert, EVP_sha1(), cert_sha1, NULL);
270 /* Recompute SHA1 hash of certificate if necessary (side effect). */
271 X509_check_purpose(cert, -1, 0);
273 /* Look for cert in the cert_ids vector. */
274 for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) {
275 ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i);
277 if (cid->hash->length == SHA_DIGEST_LENGTH
278 && memcmp(cid->hash->data, cert_sha1, SHA_DIGEST_LENGTH) == 0) {
279 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
280 if (!is || !ts_issuer_serial_cmp(is, cert))
288 /* Returns < 0 if certificate is not found, certificate index otherwise. */
289 static int ts_find_cert_v2(STACK_OF(ESS_CERT_ID_V2) *cert_ids, X509 *cert)
292 unsigned char cert_digest[EVP_MAX_MD_SIZE];
295 /* Look for cert in the cert_ids vector. */
296 for (i = 0; i < sk_ESS_CERT_ID_V2_num(cert_ids); ++i) {
297 ESS_CERT_ID_V2 *cid = sk_ESS_CERT_ID_V2_value(cert_ids, i);
300 if (cid->hash_alg != NULL)
301 md = EVP_get_digestbyobj(cid->hash_alg->algorithm);
305 X509_digest(cert, md, cert_digest, &len);
306 if (cid->hash->length != (int)len)
309 if (memcmp(cid->hash->data, cert_digest, cid->hash->length) == 0) {
310 ESS_ISSUER_SERIAL *is = cid->issuer_serial;
312 if (is == NULL || !ts_issuer_serial_cmp(is, cert))
320 static int ts_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509 *cert)
322 GENERAL_NAME *issuer;
324 if (!is || !cert || sk_GENERAL_NAME_num(is->issuer) != 1)
327 issuer = sk_GENERAL_NAME_value(is->issuer, 0);
328 if (issuer->type != GEN_DIRNAME
329 || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)))
332 if (ASN1_INTEGER_cmp(is->serial, X509_get_serialNumber(cert)))
339 * Verifies whether 'response' contains a valid response with regards
340 * to the settings of the context:
341 * - Gives an error message if the TS_TST_INFO is not present.
342 * - Calls _TS_RESP_verify_token to verify the token content.
344 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
346 PKCS7 *token = response->token;
347 TS_TST_INFO *tst_info = response->tst_info;
350 if (!ts_check_status_info(response))
352 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
361 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
362 * calls the internal int_TS_RESP_verify_token function for verifying it.
364 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
366 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
369 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
370 TS_TST_INFO_free(tst_info);
376 * Verifies whether the 'token' contains a valid time stamp token
377 * with regards to the settings of the context. Only those checks are
378 * carried out that are specified in the context:
379 * - Verifies the signature of the TS_TST_INFO.
380 * - Checks the version number of the response.
381 * - Check if the requested and returned policies math.
382 * - Check if the message imprints are the same.
383 * - Check if the nonces are the same.
384 * - Check if the TSA name matches the signer.
385 * - Check if the TSA name is the expected TSA.
387 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
388 PKCS7 *token, TS_TST_INFO *tst_info)
391 GENERAL_NAME *tsa_name = tst_info->tsa;
392 X509_ALGOR *md_alg = NULL;
393 unsigned char *imprint = NULL;
394 unsigned imprint_len = 0;
396 int flags = ctx->flags;
398 /* Some options require us to also check the signature */
399 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
400 || (flags & TS_VFY_TSA_NAME)) {
401 flags |= TS_VFY_SIGNATURE;
404 if ((flags & TS_VFY_SIGNATURE)
405 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
407 if ((flags & TS_VFY_VERSION)
408 && TS_TST_INFO_get_version(tst_info) != 1) {
409 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION);
412 if ((flags & TS_VFY_POLICY)
413 && !ts_check_policy(ctx->policy, tst_info))
415 if ((flags & TS_VFY_IMPRINT)
416 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
419 if ((flags & TS_VFY_DATA)
420 && (!ts_compute_imprint(ctx->data, tst_info,
421 &md_alg, &imprint, &imprint_len)
422 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
424 if ((flags & TS_VFY_NONCE)
425 && !ts_check_nonces(ctx->nonce, tst_info))
427 if ((flags & TS_VFY_SIGNER)
428 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
429 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH);
432 if ((flags & TS_VFY_TSA_NAME)
433 && !ts_check_signer_name(ctx->tsa_name, signer)) {
434 TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED);
441 X509_ALGOR_free(md_alg);
442 OPENSSL_free(imprint);
446 static int ts_check_status_info(TS_RESP *response)
448 TS_STATUS_INFO *info = response->status_info;
449 long status = ASN1_INTEGER_get(info->status);
450 const char *status_text = NULL;
451 char *embedded_status_text = NULL;
452 char failure_text[TS_STATUS_BUF_SIZE] = "";
454 if (status == 0 || status == 1)
457 /* There was an error, get the description in status_text. */
458 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
459 status_text = ts_status_text[status];
461 status_text = "unknown code";
463 if (sk_ASN1_UTF8STRING_num(info->text) > 0
464 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
467 /* Fill in failure_text with the failure information. */
468 if (info->failure_info) {
471 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
472 if (ASN1_BIT_STRING_get_bit(info->failure_info,
473 ts_failure_info[i].code)) {
475 strcat(failure_text, ",");
478 strcat(failure_text, ts_failure_info[i].text);
482 if (failure_text[0] == '\0')
483 strcpy(failure_text, "unspecified");
485 TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN);
486 ERR_add_error_data(6,
487 "status code: ", status_text,
488 ", status text: ", embedded_status_text ?
489 embedded_status_text : "unspecified",
490 ", failure codes: ", failure_text);
491 OPENSSL_free(embedded_status_text);
496 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
503 for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) {
504 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
505 if (ASN1_STRING_length(current) > TS_MAX_STATUS_LENGTH - length - 1)
507 length += ASN1_STRING_length(current);
508 length += 1; /* separator character */
510 if ((result = OPENSSL_malloc(length)) == NULL) {
511 TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE);
515 for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i) {
516 ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i);
517 length = ASN1_STRING_length(current);
520 strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
528 static int ts_check_policy(const ASN1_OBJECT *req_oid,
529 const TS_TST_INFO *tst_info)
531 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
533 if (OBJ_cmp(req_oid, resp_oid) != 0) {
534 TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH);
541 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
543 unsigned char **imprint, unsigned *imprint_len)
545 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
546 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
548 EVP_MD_CTX *md_ctx = NULL;
549 unsigned char buffer[4096];
555 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
557 if ((md = EVP_get_digestbyobj((*md_alg)->algorithm)) == NULL) {
558 TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM);
561 length = EVP_MD_size(md);
564 *imprint_len = length;
565 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
566 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
570 md_ctx = EVP_MD_CTX_new();
571 if (md_ctx == NULL) {
572 TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE);
575 if (!EVP_DigestInit(md_ctx, md))
577 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
578 if (!EVP_DigestUpdate(md_ctx, buffer, length))
581 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
583 EVP_MD_CTX_free(md_ctx);
587 EVP_MD_CTX_free(md_ctx);
588 X509_ALGOR_free(*md_alg);
589 OPENSSL_free(*imprint);
595 static int ts_check_imprints(X509_ALGOR *algor_a,
596 const unsigned char *imprint_a, unsigned len_a,
597 TS_TST_INFO *tst_info)
599 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
600 X509_ALGOR *algor_b = b->hash_algo;
604 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
607 /* The parameter must be NULL in both. */
608 if ((algor_a->parameter
609 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
610 || (algor_b->parameter
611 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
615 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
616 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
619 TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH);
623 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
625 const ASN1_INTEGER *b = tst_info->nonce;
628 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED);
632 /* No error if a nonce is returned without being requested. */
633 if (ASN1_INTEGER_cmp(a, b) != 0) {
634 TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH);
642 * Check if the specified TSA name matches either the subject or one of the
643 * subject alternative names of the TSA certificate.
645 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
647 STACK_OF(GENERAL_NAME) *gen_names = NULL;
651 if (tsa_name->type == GEN_DIRNAME
652 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
654 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
655 while (gen_names != NULL) {
656 found = ts_find_name(gen_names, tsa_name) >= 0;
660 * Get the next subject alternative name, although there should be no
663 GENERAL_NAMES_free(gen_names);
664 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
666 GENERAL_NAMES_free(gen_names);
671 /* Returns 1 if name is in gen_names, 0 otherwise. */
672 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
675 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
676 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
677 found = GENERAL_NAME_cmp(current, name) == 0;
679 return found ? i - 1 : -1;