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 <openssl/objects.h>
12 #include <openssl/ts.h>
13 #include <openssl/pkcs7.h>
14 #include "internal/cryptlib.h"
15 #include "internal/sizes.h"
16 #include "crypto/ess.h"
19 static int ts_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted,
20 X509 *signer, STACK_OF(X509) **chain);
21 static int ts_check_signing_certs(const PKCS7_SIGNER_INFO *si,
22 const STACK_OF(X509) *chain);
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,
42 * This must be large enough to hold all values in ts_status_text (with
43 * comma separator) or all text fields in ts_failure_info (also with comma).
45 #define TS_STATUS_BUF_SIZE 256
48 * Local mapping between response codes and descriptions.
50 static const char *ts_status_text[] = {
56 "revocationNotification"
59 #define TS_STATUS_TEXT_SIZE OSSL_NELEM(ts_status_text)
64 } ts_failure_info[] = {
65 {TS_INFO_BAD_ALG, "badAlg"},
66 {TS_INFO_BAD_REQUEST, "badRequest"},
67 {TS_INFO_BAD_DATA_FORMAT, "badDataFormat"},
68 {TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable"},
69 {TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy"},
70 {TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension"},
71 {TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable"},
72 {TS_INFO_SYSTEM_FAILURE, "systemFailure"}
77 * This function carries out the following tasks:
78 * - Checks if there is one and only one signer.
79 * - Search for the signing certificate in 'certs' and in the response.
80 * - Check the extended key usage and key usage fields of the signer
81 * certificate (done by the path validation).
82 * - Build and validate the certificate path.
83 * - Check if the certificate path meets the requirements of the
84 * SigningCertificate ESS signed attribute.
85 * - Verify the signature value.
86 * - Returns the signer certificate in 'signer', if 'signer' is not NULL.
88 int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs,
89 X509_STORE *store, X509 **signer_out)
91 STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL;
92 PKCS7_SIGNER_INFO *si;
93 STACK_OF(X509) *untrusted = NULL;
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 ERR_raise(ERR_LIB_TS, TS_R_INVALID_NULL_POINTER);
106 if (!PKCS7_type_is_signed(token)) {
107 ERR_raise(ERR_LIB_TS, TS_R_WRONG_CONTENT_TYPE);
110 sinfos = PKCS7_get_signer_info(token);
111 if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) {
112 ERR_raise(ERR_LIB_TS, TS_R_THERE_MUST_BE_ONE_SIGNER);
115 si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0);
116 if (PKCS7_get_detached(token)) {
117 ERR_raise(ERR_LIB_TS, 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 untrusted = sk_X509_new_reserve(NULL, sk_X509_num(certs)
131 + sk_X509_num(token->d.sign->cert));
132 if (untrusted == NULL
133 || !X509_add_certs(untrusted, certs, 0)
134 || !X509_add_certs(untrusted, token->d.sign->cert, 0))
136 if (!ts_verify_cert(store, untrusted, signer, &chain))
138 if (!ts_check_signing_certs(si, chain))
140 p7bio = PKCS7_dataInit(token, NULL);
142 /* We now have to 'read' from p7bio to calculate digests etc. */
143 while ((i = BIO_read(p7bio, buf, sizeof(buf))) > 0)
146 j = PKCS7_signatureVerify(p7bio, token, si, signer);
148 ERR_raise(ERR_LIB_TS, TS_R_SIGNATURE_FAILURE);
153 *signer_out = signer;
160 sk_X509_free(untrusted);
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 ERR_raise(ERR_LIB_TS, 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 ERR_raise_data(ERR_LIB_TS, TS_R_CERTIFICATE_VERIFY_ERROR,
191 "Verify error:%s", X509_verify_cert_error_string(j));
194 *chain = X509_STORE_CTX_get1_chain(cert_ctx);
202 X509_STORE_CTX_free(cert_ctx);
206 static ESS_SIGNING_CERT *ossl_ess_get_signing_cert(const PKCS7_SIGNER_INFO *si)
209 const unsigned char *p;
211 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
214 p = attr->value.sequence->data;
215 return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
219 ESS_SIGNING_CERT_V2 *ossl_ess_get_signing_cert_v2(const PKCS7_SIGNER_INFO *si)
222 const unsigned char *p;
224 attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificateV2);
227 p = attr->value.sequence->data;
228 return d2i_ESS_SIGNING_CERT_V2(NULL, &p, attr->value.sequence->length);
231 static int ts_check_signing_certs(const PKCS7_SIGNER_INFO *si,
232 const STACK_OF(X509) *chain)
234 ESS_SIGNING_CERT *ss = ossl_ess_get_signing_cert(si);
235 ESS_SIGNING_CERT_V2 *ssv2 = ossl_ess_get_signing_cert_v2(si);
236 int ret = OSSL_ESS_check_signing_certs(ss, ssv2, chain, 1) > 0;
238 ESS_SIGNING_CERT_free(ss);
239 ESS_SIGNING_CERT_V2_free(ssv2);
244 * Verifies whether 'response' contains a valid response with regards
245 * to the settings of the context:
246 * - Gives an error message if the TS_TST_INFO is not present.
247 * - Calls _TS_RESP_verify_token to verify the token content.
249 int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response)
251 PKCS7 *token = response->token;
252 TS_TST_INFO *tst_info = response->tst_info;
255 if (!ts_check_status_info(response))
257 if (!int_ts_RESP_verify_token(ctx, token, tst_info))
266 * Tries to extract a TS_TST_INFO structure from the PKCS7 token and
267 * calls the internal int_TS_RESP_verify_token function for verifying it.
269 int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token)
271 TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token);
274 ret = int_ts_RESP_verify_token(ctx, token, tst_info);
275 TS_TST_INFO_free(tst_info);
281 * Verifies whether the 'token' contains a valid time stamp token
282 * with regards to the settings of the context. Only those checks are
283 * carried out that are specified in the context:
284 * - Verifies the signature of the TS_TST_INFO.
285 * - Checks the version number of the response.
286 * - Check if the requested and returned policies math.
287 * - Check if the message imprints are the same.
288 * - Check if the nonces are the same.
289 * - Check if the TSA name matches the signer.
290 * - Check if the TSA name is the expected TSA.
292 static int int_ts_RESP_verify_token(TS_VERIFY_CTX *ctx,
293 PKCS7 *token, TS_TST_INFO *tst_info)
296 GENERAL_NAME *tsa_name = tst_info->tsa;
297 X509_ALGOR *md_alg = NULL;
298 unsigned char *imprint = NULL;
299 unsigned imprint_len = 0;
301 int flags = ctx->flags;
303 /* Some options require us to also check the signature */
304 if (((flags & TS_VFY_SIGNER) && tsa_name != NULL)
305 || (flags & TS_VFY_TSA_NAME)) {
306 flags |= TS_VFY_SIGNATURE;
309 if ((flags & TS_VFY_SIGNATURE)
310 && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer))
312 if ((flags & TS_VFY_VERSION)
313 && TS_TST_INFO_get_version(tst_info) != 1) {
314 ERR_raise(ERR_LIB_TS, TS_R_UNSUPPORTED_VERSION);
317 if ((flags & TS_VFY_POLICY)
318 && !ts_check_policy(ctx->policy, tst_info))
320 if ((flags & TS_VFY_IMPRINT)
321 && !ts_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len,
324 if ((flags & TS_VFY_DATA)
325 && (!ts_compute_imprint(ctx->data, tst_info,
326 &md_alg, &imprint, &imprint_len)
327 || !ts_check_imprints(md_alg, imprint, imprint_len, tst_info)))
329 if ((flags & TS_VFY_NONCE)
330 && !ts_check_nonces(ctx->nonce, tst_info))
332 if ((flags & TS_VFY_SIGNER)
333 && tsa_name && !ts_check_signer_name(tsa_name, signer)) {
334 ERR_raise(ERR_LIB_TS, TS_R_TSA_NAME_MISMATCH);
337 if ((flags & TS_VFY_TSA_NAME)
338 && !ts_check_signer_name(ctx->tsa_name, signer)) {
339 ERR_raise(ERR_LIB_TS, TS_R_TSA_UNTRUSTED);
346 X509_ALGOR_free(md_alg);
347 OPENSSL_free(imprint);
351 static int ts_check_status_info(TS_RESP *response)
353 TS_STATUS_INFO *info = response->status_info;
354 long status = ASN1_INTEGER_get(info->status);
355 const char *status_text = NULL;
356 char *embedded_status_text = NULL;
357 char failure_text[TS_STATUS_BUF_SIZE] = "";
359 if (status == 0 || status == 1)
362 /* There was an error, get the description in status_text. */
363 if (0 <= status && status < (long) OSSL_NELEM(ts_status_text))
364 status_text = ts_status_text[status];
366 status_text = "unknown code";
368 if (sk_ASN1_UTF8STRING_num(info->text) > 0
369 && (embedded_status_text = ts_get_status_text(info->text)) == NULL)
372 /* Fill in failure_text with the failure information. */
373 if (info->failure_info) {
376 for (i = 0; i < (int)OSSL_NELEM(ts_failure_info); ++i) {
377 if (ASN1_BIT_STRING_get_bit(info->failure_info,
378 ts_failure_info[i].code)) {
380 strcat(failure_text, ",");
383 strcat(failure_text, ts_failure_info[i].text);
387 if (failure_text[0] == '\0')
388 strcpy(failure_text, "unspecified");
390 ERR_raise_data(ERR_LIB_TS, TS_R_NO_TIME_STAMP_TOKEN,
391 "status code: %s, status text: %s, failure codes: %s",
393 embedded_status_text ? embedded_status_text : "unspecified",
395 OPENSSL_free(embedded_status_text);
400 static char *ts_get_status_text(STACK_OF(ASN1_UTF8STRING) *text)
402 return ossl_sk_ASN1_UTF8STRING2text(text, "/", TS_MAX_STATUS_LENGTH);
405 static int ts_check_policy(const ASN1_OBJECT *req_oid,
406 const TS_TST_INFO *tst_info)
408 const ASN1_OBJECT *resp_oid = tst_info->policy_id;
410 if (OBJ_cmp(req_oid, resp_oid) != 0) {
411 ERR_raise(ERR_LIB_TS, TS_R_POLICY_MISMATCH);
418 static int ts_compute_imprint(BIO *data, TS_TST_INFO *tst_info,
420 unsigned char **imprint, unsigned *imprint_len)
422 TS_MSG_IMPRINT *msg_imprint = tst_info->msg_imprint;
423 X509_ALGOR *md_alg_resp = msg_imprint->hash_algo;
425 EVP_MD_CTX *md_ctx = NULL;
426 unsigned char buffer[4096];
427 char name[OSSL_MAX_NAME_SIZE];
433 if ((*md_alg = X509_ALGOR_dup(md_alg_resp)) == NULL)
436 OBJ_obj2txt(name, sizeof(name), md_alg_resp->algorithm, 0);
438 (void)ERR_set_mark();
439 md = EVP_MD_fetch(NULL, name, NULL);
442 md = (EVP_MD *)EVP_get_digestbyname(name);
445 (void)ERR_clear_last_mark();
448 (void)ERR_pop_to_mark();
450 length = EVP_MD_get_size(md);
453 *imprint_len = length;
454 if ((*imprint = OPENSSL_malloc(*imprint_len)) == NULL) {
455 ERR_raise(ERR_LIB_TS, ERR_R_MALLOC_FAILURE);
459 md_ctx = EVP_MD_CTX_new();
460 if (md_ctx == NULL) {
461 ERR_raise(ERR_LIB_TS, ERR_R_MALLOC_FAILURE);
464 if (!EVP_DigestInit(md_ctx, md))
468 while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) {
469 if (!EVP_DigestUpdate(md_ctx, buffer, length))
472 if (!EVP_DigestFinal(md_ctx, *imprint, NULL))
474 EVP_MD_CTX_free(md_ctx);
478 EVP_MD_CTX_free(md_ctx);
480 X509_ALGOR_free(*md_alg);
482 OPENSSL_free(*imprint);
488 static int ts_check_imprints(X509_ALGOR *algor_a,
489 const unsigned char *imprint_a, unsigned len_a,
490 TS_TST_INFO *tst_info)
492 TS_MSG_IMPRINT *b = tst_info->msg_imprint;
493 X509_ALGOR *algor_b = b->hash_algo;
497 if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm))
500 /* The parameter must be NULL in both. */
501 if ((algor_a->parameter
502 && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL)
503 || (algor_b->parameter
504 && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL))
508 ret = len_a == (unsigned)ASN1_STRING_length(b->hashed_msg) &&
509 memcmp(imprint_a, ASN1_STRING_get0_data(b->hashed_msg), len_a) == 0;
512 ERR_raise(ERR_LIB_TS, TS_R_MESSAGE_IMPRINT_MISMATCH);
516 static int ts_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info)
518 const ASN1_INTEGER *b = tst_info->nonce;
521 ERR_raise(ERR_LIB_TS, TS_R_NONCE_NOT_RETURNED);
525 /* No error if a nonce is returned without being requested. */
526 if (ASN1_INTEGER_cmp(a, b) != 0) {
527 ERR_raise(ERR_LIB_TS, TS_R_NONCE_MISMATCH);
535 * Check if the specified TSA name matches either the subject or one of the
536 * subject alternative names of the TSA certificate.
538 static int ts_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer)
540 STACK_OF(GENERAL_NAME) *gen_names = NULL;
544 if (tsa_name->type == GEN_DIRNAME
545 && X509_name_cmp(tsa_name->d.dirn, X509_get_subject_name(signer)) == 0)
547 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
548 while (gen_names != NULL) {
549 found = ts_find_name(gen_names, tsa_name) >= 0;
553 * Get the next subject alternative name, although there should be no
556 GENERAL_NAMES_free(gen_names);
557 gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx);
559 GENERAL_NAMES_free(gen_names);
564 /* Returns 1 if name is in gen_names, 0 otherwise. */
565 static int ts_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name)
568 for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) {
569 GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i);
570 found = GENERAL_NAME_cmp(current, name) == 0;
572 return found ? i - 1 : -1;