/* crypto/ts/ts_resp_verify.c */ /* Written by Zoltan Glozik (zglozik@stones.com) for the OpenSSL * project 2002. */ /* ==================================================================== * Copyright (c) 2006 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * licensing@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include #include "cryptlib.h" #include #include #include /* Private function declarations. */ static int TS_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted, X509 *signer, STACK_OF(X509) **chain); static int TS_check_signing_certs(PKCS7_SIGNER_INFO *si, STACK_OF(X509) *chain); static ESS_SIGNING_CERT *ESS_get_signing_cert(PKCS7_SIGNER_INFO *si); static int TS_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert); static int TS_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509_CINF *cinfo); static int int_TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token, TS_TST_INFO *tst_info); static int TS_check_status_info(TS_RESP *response); static char *TS_get_status_text(STACK_OF(ASN1_UTF8STRING) *text); static int TS_check_policy(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info); static int TS_compute_imprint(BIO *data, TS_TST_INFO *tst_info, X509_ALGOR **md_alg, unsigned char **imprint, unsigned *imprint_len); static int TS_check_imprints(X509_ALGOR *algor_a, unsigned char *imprint_a, unsigned len_a, TS_TST_INFO *tst_info); static int TS_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info); static int TS_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer); static int TS_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name); /* * Local mapping between response codes and descriptions. * Don't forget to change TS_STATUS_BUF_SIZE when modifying * the elements of this array. */ static const char *TS_status_text[] = { "granted", "grantedWithMods", "rejection", "waiting", "revocationWarning", "revocationNotification" }; #define TS_STATUS_TEXT_SIZE (sizeof(TS_status_text)/sizeof(*TS_status_text)) /* * This must be greater or equal to the sum of the strings in TS_status_text * plus the number of its elements. */ #define TS_STATUS_BUF_SIZE 256 static struct { int code; const char *text; } TS_failure_info[] = { { TS_INFO_BAD_ALG, "badAlg" }, { TS_INFO_BAD_REQUEST, "badRequest" }, { TS_INFO_BAD_DATA_FORMAT, "badDataFormat" }, { TS_INFO_TIME_NOT_AVAILABLE, "timeNotAvailable" }, { TS_INFO_UNACCEPTED_POLICY, "unacceptedPolicy" }, { TS_INFO_UNACCEPTED_EXTENSION, "unacceptedExtension" }, { TS_INFO_ADD_INFO_NOT_AVAILABLE, "addInfoNotAvailable" }, { TS_INFO_SYSTEM_FAILURE, "systemFailure" } }; #define TS_FAILURE_INFO_SIZE (sizeof(TS_failure_info) / \ sizeof(*TS_failure_info)) /* Functions for verifying a signed TS_TST_INFO structure. */ /* * This function carries out the following tasks: * - Checks if there is one and only one signer. * - Search for the signing certificate in 'certs' and in the response. * - Check the extended key usage and key usage fields of the signer * certificate (done by the path validation). * - Build and validate the certificate path. * - Check if the certificate path meets the requirements of the * SigningCertificate ESS signed attribute. * - Verify the signature value. * - Returns the signer certificate in 'signer', if 'signer' is not NULL. */ int TS_RESP_verify_signature(PKCS7 *token, STACK_OF(X509) *certs, X509_STORE *store, X509 **signer_out) { STACK_OF(PKCS7_SIGNER_INFO) *sinfos = NULL; PKCS7_SIGNER_INFO *si; STACK_OF(X509) *signers = NULL; X509 *signer; STACK_OF(X509) *chain = NULL; char buf[4096]; int i, j = 0, ret = 0; BIO *p7bio = NULL; /* Some sanity checks first. */ if (!token) { TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_INVALID_NULL_POINTER); goto err; } /* Check for the correct content type */ if(!PKCS7_type_is_signed(token)) { TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_WRONG_CONTENT_TYPE); goto err; } /* Check if there is one and only one signer. */ sinfos = PKCS7_get_signer_info(token); if (!sinfos || sk_PKCS7_SIGNER_INFO_num(sinfos) != 1) { TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_THERE_MUST_BE_ONE_SIGNER); goto err; } si = sk_PKCS7_SIGNER_INFO_value(sinfos, 0); /* Check for no content: no data to verify signature. */ if (PKCS7_get_detached(token)) { TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_NO_CONTENT); goto err; } /* Get hold of the signer certificate, search only internal certificates if it was requested. */ signers = PKCS7_get0_signers(token, certs, 0); if (!signers || sk_X509_num(signers) != 1) goto err; signer = sk_X509_value(signers, 0); /* Now verify the certificate. */ if (!TS_verify_cert(store, certs, signer, &chain)) goto err; /* Check if the signer certificate is consistent with the ESS extension. */ if (!TS_check_signing_certs(si, chain)) goto err; /* Creating the message digest. */ p7bio = PKCS7_dataInit(token, NULL); /* We now have to 'read' from p7bio to calculate digests etc. */ while ((i = BIO_read(p7bio,buf,sizeof(buf))) > 0); /* Verifying the signature. */ j = PKCS7_signatureVerify(p7bio, token, si, signer); if (j <= 0) { TSerr(TS_F_TS_RESP_VERIFY_SIGNATURE, TS_R_SIGNATURE_FAILURE); goto err; } /* Return the signer certificate if needed. */ if (signer_out) { *signer_out = signer; CRYPTO_add(&signer->references, 1, CRYPTO_LOCK_X509); } ret = 1; err: BIO_free_all(p7bio); sk_X509_pop_free(chain, X509_free); sk_X509_free(signers); return ret; } /* * The certificate chain is returned in chain. Caller is responsible for * freeing the vector. */ static int TS_verify_cert(X509_STORE *store, STACK_OF(X509) *untrusted, X509 *signer, STACK_OF(X509) **chain) { X509_STORE_CTX cert_ctx; int i; int ret = 1; /* chain is an out argument. */ *chain = NULL; X509_STORE_CTX_init(&cert_ctx, store, signer, untrusted); X509_STORE_CTX_set_purpose(&cert_ctx, X509_PURPOSE_TIMESTAMP_SIGN); i = X509_verify_cert(&cert_ctx); if (i <= 0) { int j = X509_STORE_CTX_get_error(&cert_ctx); TSerr(TS_F_TS_VERIFY_CERT, TS_R_CERTIFICATE_VERIFY_ERROR); ERR_add_error_data(2, "Verify error:", X509_verify_cert_error_string(j)); ret = 0; } else { /* Get a copy of the certificate chain. */ *chain = X509_STORE_CTX_get1_chain(&cert_ctx); } X509_STORE_CTX_cleanup(&cert_ctx); return ret; } static int TS_check_signing_certs(PKCS7_SIGNER_INFO *si, STACK_OF(X509) *chain) { ESS_SIGNING_CERT *ss = ESS_get_signing_cert(si); STACK_OF(ESS_CERT_ID) *cert_ids = NULL; X509 *cert; int i = 0; int ret = 0; if (!ss) goto err; cert_ids = ss->cert_ids; /* The signer certificate must be the first in cert_ids. */ cert = sk_X509_value(chain, 0); if (TS_find_cert(cert_ids, cert) != 0) goto err; /* Check the other certificates of the chain if there are more than one certificate ids in cert_ids. */ if (sk_ESS_CERT_ID_num(cert_ids) > 1) { /* All the certificates of the chain must be in cert_ids. */ for (i = 1; i < sk_X509_num(chain); ++i) { cert = sk_X509_value(chain, i); if (TS_find_cert(cert_ids, cert) < 0) goto err; } } ret = 1; err: if (!ret) TSerr(TS_F_TS_CHECK_SIGNING_CERTS, TS_R_ESS_SIGNING_CERTIFICATE_ERROR); ESS_SIGNING_CERT_free(ss); return ret; } static ESS_SIGNING_CERT *ESS_get_signing_cert(PKCS7_SIGNER_INFO *si) { ASN1_TYPE *attr; const unsigned char *p; attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate); if (!attr) return NULL; p = attr->value.sequence->data; return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length); } /* Returns < 0 if certificate is not found, certificate index otherwise. */ static int TS_find_cert(STACK_OF(ESS_CERT_ID) *cert_ids, X509 *cert) { int i; if (!cert_ids || !cert) return -1; /* Recompute SHA1 hash of certificate if necessary (side effect). */ X509_check_purpose(cert, -1, 0); /* Look for cert in the cert_ids vector. */ for (i = 0; i < sk_ESS_CERT_ID_num(cert_ids); ++i) { ESS_CERT_ID *cid = sk_ESS_CERT_ID_value(cert_ids, i); /* Check the SHA-1 hash first. */ if (cid->hash->length == sizeof(cert->sha1_hash) && !memcmp(cid->hash->data, cert->sha1_hash, sizeof(cert->sha1_hash))) { /* Check the issuer/serial as well if specified. */ ESS_ISSUER_SERIAL *is = cid->issuer_serial; if (!is || !TS_issuer_serial_cmp(is, cert->cert_info)) return i; } } return -1; } static int TS_issuer_serial_cmp(ESS_ISSUER_SERIAL *is, X509_CINF *cinfo) { GENERAL_NAME *issuer; if (!is || !cinfo || sk_GENERAL_NAME_num(is->issuer) != 1) return -1; /* Check the issuer first. It must be a directory name. */ issuer = sk_GENERAL_NAME_value(is->issuer, 0); if (issuer->type != GEN_DIRNAME || X509_NAME_cmp(issuer->d.dirn, cinfo->issuer)) return -1; /* Check the serial number, too. */ if (ASN1_INTEGER_cmp(is->serial, cinfo->serialNumber)) return -1; return 0; } /* * Verifies whether 'response' contains a valid response with regards * to the settings of the context: * - Gives an error message if the TS_TST_INFO is not present. * - Calls _TS_RESP_verify_token to verify the token content. */ int TS_RESP_verify_response(TS_VERIFY_CTX *ctx, TS_RESP *response) { PKCS7 *token = TS_RESP_get_token(response); TS_TST_INFO *tst_info = TS_RESP_get_tst_info(response); int ret = 0; /* Check if we have a successful TS_TST_INFO object in place. */ if (!TS_check_status_info(response)) goto err; /* Check the contents of the time stamp token. */ if (!int_TS_RESP_verify_token(ctx, token, tst_info)) goto err; ret = 1; err: return ret; } /* * Tries to extract a TS_TST_INFO structure from the PKCS7 token and * calls the internal int_TS_RESP_verify_token function for verifying it. */ int TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token) { TS_TST_INFO *tst_info = PKCS7_to_TS_TST_INFO(token); int ret = 0; if (tst_info) { ret = int_TS_RESP_verify_token(ctx, token, tst_info); TS_TST_INFO_free(tst_info); } return ret; } /* * Verifies whether the 'token' contains a valid time stamp token * with regards to the settings of the context. Only those checks are * carried out that are specified in the context: * - Verifies the signature of the TS_TST_INFO. * - Checks the version number of the response. * - Check if the requested and returned policies math. * - Check if the message imprints are the same. * - Check if the nonces are the same. * - Check if the TSA name matches the signer. * - Check if the TSA name is the expected TSA. */ static int int_TS_RESP_verify_token(TS_VERIFY_CTX *ctx, PKCS7 *token, TS_TST_INFO *tst_info) { X509 *signer = NULL; GENERAL_NAME *tsa_name = TS_TST_INFO_get_tsa(tst_info); X509_ALGOR *md_alg = NULL; unsigned char *imprint = NULL; unsigned imprint_len = 0; int ret = 0; /* Verify the signature. */ if ((ctx->flags & TS_VFY_SIGNATURE) && !TS_RESP_verify_signature(token, ctx->certs, ctx->store, &signer)) goto err; /* Check version number of response. */ if ((ctx->flags & TS_VFY_VERSION) && TS_TST_INFO_get_version(tst_info) != 1) { TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_UNSUPPORTED_VERSION); goto err; } /* Check policies. */ if ((ctx->flags & TS_VFY_POLICY) && !TS_check_policy(ctx->policy, tst_info)) goto err; /* Check message imprints. */ if ((ctx->flags & TS_VFY_IMPRINT) && !TS_check_imprints(ctx->md_alg, ctx->imprint, ctx->imprint_len, tst_info)) goto err; /* Compute and check message imprints. */ if ((ctx->flags & TS_VFY_DATA) && (!TS_compute_imprint(ctx->data, tst_info, &md_alg, &imprint, &imprint_len) || !TS_check_imprints(md_alg, imprint, imprint_len, tst_info))) goto err; /* Check nonces. */ if ((ctx->flags & TS_VFY_NONCE) && !TS_check_nonces(ctx->nonce, tst_info)) goto err; /* Check whether TSA name and signer certificate match. */ if ((ctx->flags & TS_VFY_SIGNER) && tsa_name && !TS_check_signer_name(tsa_name, signer)) { TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_NAME_MISMATCH); goto err; } /* Check whether the TSA is the expected one. */ if ((ctx->flags & TS_VFY_TSA_NAME) && !TS_check_signer_name(ctx->tsa_name, signer)) { TSerr(TS_F_INT_TS_RESP_VERIFY_TOKEN, TS_R_TSA_UNTRUSTED); goto err; } ret = 1; err: X509_free(signer); X509_ALGOR_free(md_alg); free(imprint); return ret; } static int TS_check_status_info(TS_RESP *response) { TS_STATUS_INFO *info = TS_RESP_get_status_info(response); long status = ASN1_INTEGER_get(info->status); const char *status_text = NULL; char *embedded_status_text = NULL; char failure_text[TS_STATUS_BUF_SIZE] = ""; /* Check if everything went fine. */ if (status == 0 || status == 1) return 1; /* There was an error, get the description in status_text. */ if (0 <= status && status < (long)TS_STATUS_TEXT_SIZE) status_text = TS_status_text[status]; else status_text = "unknown code"; /* Set the embedded_status_text to the returned description. */ if (sk_ASN1_UTF8STRING_num(info->text) > 0 && !(embedded_status_text = TS_get_status_text(info->text))) return 0; /* Filling in failure_text with the failure information. */ if (info->failure_info) { int i; int first = 1; for (i = 0; i < (int)TS_FAILURE_INFO_SIZE; ++i) { if (ASN1_BIT_STRING_get_bit(info->failure_info, TS_failure_info[i].code)) { if (!first) strlcat(failure_text, ",", TS_STATUS_BUF_SIZE); else first = 0; strlcat(failure_text, TS_failure_info[i].text, TS_STATUS_BUF_SIZE); } } } if (failure_text[0] == '\0') strlcpy(failure_text, "unspecified", TS_STATUS_BUF_SIZE); /* Making up the error string. */ TSerr(TS_F_TS_CHECK_STATUS_INFO, TS_R_NO_TIME_STAMP_TOKEN); ERR_add_error_data(6, "status code: ", status_text, ", status text: ", embedded_status_text ? embedded_status_text : "unspecified", ", failure codes: ", failure_text); free(embedded_status_text); return 0; } static char *TS_get_status_text(STACK_OF(ASN1_UTF8STRING) *text) { int i; unsigned int length = 0; char *result = NULL; /* Determine length first. */ for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) { ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i); length += ASN1_STRING_length(current); length += 1; /* separator character */ } /* Allocate memory (closing '\0' included). */ if (!(result = malloc(length))) { TSerr(TS_F_TS_GET_STATUS_TEXT, ERR_R_MALLOC_FAILURE); return NULL; } /* Concatenate the descriptions. */ result[0] = '\0'; for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) { ASN1_UTF8STRING *current = sk_ASN1_UTF8STRING_value(text, i); if (i > 0) strlcat(result, "/", length); strlcat(result, ASN1_STRING_data(current), length); } return result; } static int TS_check_policy(ASN1_OBJECT *req_oid, TS_TST_INFO *tst_info) { ASN1_OBJECT *resp_oid = TS_TST_INFO_get_policy_id(tst_info); if (OBJ_cmp(req_oid, resp_oid) != 0) { TSerr(TS_F_TS_CHECK_POLICY, TS_R_POLICY_MISMATCH); return 0; } return 1; } static int TS_compute_imprint(BIO *data, TS_TST_INFO *tst_info, X509_ALGOR **md_alg, unsigned char **imprint, unsigned *imprint_len) { TS_MSG_IMPRINT *msg_imprint = TS_TST_INFO_get_msg_imprint(tst_info); X509_ALGOR *md_alg_resp = TS_MSG_IMPRINT_get_algo(msg_imprint); const EVP_MD *md; EVP_MD_CTX md_ctx; unsigned char buffer[4096]; int length; *md_alg = NULL; *imprint = NULL; /* Return the MD algorithm of the response. */ if (!(*md_alg = X509_ALGOR_dup(md_alg_resp))) goto err; /* Getting the MD object. */ if (!(md = EVP_get_digestbyobj((*md_alg)->algorithm))) { TSerr(TS_F_TS_COMPUTE_IMPRINT, TS_R_UNSUPPORTED_MD_ALGORITHM); goto err; } /* Compute message digest. */ length = EVP_MD_size(md); if (length < 0) goto err; *imprint_len = length; if (!(*imprint = malloc(*imprint_len))) { TSerr(TS_F_TS_COMPUTE_IMPRINT, ERR_R_MALLOC_FAILURE); goto err; } if (!EVP_DigestInit(&md_ctx, md)) goto err; while ((length = BIO_read(data, buffer, sizeof(buffer))) > 0) { if (!EVP_DigestUpdate(&md_ctx, buffer, length)) goto err; } if (!EVP_DigestFinal(&md_ctx, *imprint, NULL)) goto err; return 1; err: X509_ALGOR_free(*md_alg); free(*imprint); *imprint_len = 0; return 0; } static int TS_check_imprints(X509_ALGOR *algor_a, unsigned char *imprint_a, unsigned len_a, TS_TST_INFO *tst_info) { TS_MSG_IMPRINT *b = TS_TST_INFO_get_msg_imprint(tst_info); X509_ALGOR *algor_b = TS_MSG_IMPRINT_get_algo(b); int ret = 0; /* algor_a is optional. */ if (algor_a) { /* Compare algorithm OIDs. */ if (OBJ_cmp(algor_a->algorithm, algor_b->algorithm)) goto err; /* The parameter must be NULL in both. */ if ((algor_a->parameter && ASN1_TYPE_get(algor_a->parameter) != V_ASN1_NULL) || (algor_b->parameter && ASN1_TYPE_get(algor_b->parameter) != V_ASN1_NULL)) goto err; } /* Compare octet strings. */ ret = len_a == (unsigned) ASN1_STRING_length(b->hashed_msg) && memcmp(imprint_a, ASN1_STRING_data(b->hashed_msg), len_a) == 0; err: if (!ret) TSerr(TS_F_TS_CHECK_IMPRINTS, TS_R_MESSAGE_IMPRINT_MISMATCH); return ret; } static int TS_check_nonces(const ASN1_INTEGER *a, TS_TST_INFO *tst_info) { const ASN1_INTEGER *b = TS_TST_INFO_get_nonce(tst_info); /* Error if nonce is missing. */ if (!b) { TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_NOT_RETURNED); return 0; } /* No error if a nonce is returned without being requested. */ if (ASN1_INTEGER_cmp(a, b) != 0) { TSerr(TS_F_TS_CHECK_NONCES, TS_R_NONCE_MISMATCH); return 0; } return 1; } /* Check if the specified TSA name matches either the subject or one of the subject alternative names of the TSA certificate. */ static int TS_check_signer_name(GENERAL_NAME *tsa_name, X509 *signer) { STACK_OF(GENERAL_NAME) *gen_names = NULL; int idx = -1; int found = 0; /* Check the subject name first. */ if (tsa_name->type == GEN_DIRNAME && X509_name_cmp(tsa_name->d.dirn, signer->cert_info->subject) == 0) return 1; /* Check all the alternative names. */ gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx); while (gen_names != NULL && !(found = TS_find_name(gen_names, tsa_name) >= 0)) { /* Get the next subject alternative name, although there should be no more than one. */ GENERAL_NAMES_free(gen_names); gen_names = X509_get_ext_d2i(signer, NID_subject_alt_name, NULL, &idx); } if (gen_names) GENERAL_NAMES_free(gen_names); return found; } /* Returns 1 if name is in gen_names, 0 otherwise. */ static int TS_find_name(STACK_OF(GENERAL_NAME) *gen_names, GENERAL_NAME *name) { int i, found; for (i = 0, found = 0; !found && i < sk_GENERAL_NAME_num(gen_names); ++i) { GENERAL_NAME *current = sk_GENERAL_NAME_value(gen_names, i); found = GENERAL_NAME_cmp(current, name) == 0; } return found ? i - 1 : -1; }