A local copy of OpenSSL from GitHub
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/*
* Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/ocsp.h>
#include "ocsp_lcl.h"
#include <openssl/err.h>
#include <string.h>
static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
STACK_OF(X509) *certs, unsigned long flags);
static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain);
static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp,
OCSP_CERTID **ret);
static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
STACK_OF(OCSP_SINGLERESP) *sresp);
static int ocsp_check_delegated(X509 *x);
static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
X509_NAME *nm, STACK_OF(X509) *certs,
unsigned long flags);
/* Verify a basic response message */
int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
X509_STORE *st, unsigned long flags)
{
X509 *signer, *x;
STACK_OF(X509) *chain = NULL;
STACK_OF(X509) *untrusted = NULL;
X509_STORE_CTX *ctx = NULL;
int i, ret = ocsp_find_signer(&signer, bs, certs, flags);
if (!ret) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
goto end;
}
ctx = X509_STORE_CTX_new();
if (ctx == NULL) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
goto f_err;
}
if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
flags |= OCSP_NOVERIFY;
if (!(flags & OCSP_NOSIGS)) {
EVP_PKEY *skey;
skey = X509_get0_pubkey(signer);
if (skey == NULL) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_NO_SIGNER_KEY);
goto err;
}
ret = OCSP_BASICRESP_verify(bs, skey, 0);
if (ret <= 0) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
goto end;
}
}
if (!(flags & OCSP_NOVERIFY)) {
int init_res;
if (flags & OCSP_NOCHAIN) {
untrusted = NULL;
} else if (bs->certs && certs) {
untrusted = sk_X509_dup(bs->certs);
for (i = 0; i < sk_X509_num(certs); i++) {
if (!sk_X509_push(untrusted, sk_X509_value(certs, i))) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
goto f_err;
}
}
} else {
untrusted = bs->certs;
}
init_res = X509_STORE_CTX_init(ctx, st, signer, untrusted);
if (!init_res) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_X509_LIB);
goto f_err;
}
X509_STORE_CTX_set_purpose(ctx, X509_PURPOSE_OCSP_HELPER);
ret = X509_verify_cert(ctx);
chain = X509_STORE_CTX_get1_chain(ctx);
if (ret <= 0) {
i = X509_STORE_CTX_get_error(ctx);
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
OCSP_R_CERTIFICATE_VERIFY_ERROR);
ERR_add_error_data(2, "Verify error:",
X509_verify_cert_error_string(i));
goto end;
}
if (flags & OCSP_NOCHECKS) {
ret = 1;
goto end;
}
/*
* At this point we have a valid certificate chain need to verify it
* against the OCSP issuer criteria.
*/
ret = ocsp_check_issuer(bs, chain);
/* If fatal error or valid match then finish */
if (ret != 0)
goto end;
/*
* Easy case: explicitly trusted. Get root CA and check for explicit
* trust
*/
if (flags & OCSP_NOEXPLICIT)
goto end;
x = sk_X509_value(chain, sk_X509_num(chain) - 1);
if (X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) {
OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_ROOT_CA_NOT_TRUSTED);
goto err;
}
ret = 1;
}
end:
X509_STORE_CTX_free(ctx);
sk_X509_pop_free(chain, X509_free);
if (bs->certs && certs)
sk_X509_free(untrusted);
return ret;
err:
ret = 0;
goto end;
f_err:
ret = -1;
goto end;
}
static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
STACK_OF(X509) *certs, unsigned long flags)
{
X509 *signer;
OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
if ((signer = ocsp_find_signer_sk(certs, rid))) {
*psigner = signer;
return 2;
}
if (!(flags & OCSP_NOINTERN) &&
(signer = ocsp_find_signer_sk(bs->certs, rid))) {
*psigner = signer;
return 1;
}
/* Maybe lookup from store if by subject name */
*psigner = NULL;
return 0;
}
static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
{
int i;
unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
X509 *x;
/* Easy if lookup by name */
if (id->type == V_OCSP_RESPID_NAME)
return X509_find_by_subject(certs, id->value.byName);
/* Lookup by key hash */
/* If key hash isn't SHA1 length then forget it */
if (id->value.byKey->length != SHA_DIGEST_LENGTH)
return NULL;
keyhash = id->value.byKey->data;
/* Calculate hash of each key and compare */
for (i = 0; i < sk_X509_num(certs); i++) {
x = sk_X509_value(certs, i);
X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
if (!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
return x;
}
return NULL;
}
static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain)
{
STACK_OF(OCSP_SINGLERESP) *sresp;
X509 *signer, *sca;
OCSP_CERTID *caid = NULL;
int i;
sresp = bs->tbsResponseData.responses;
if (sk_X509_num(chain) <= 0) {
OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
return -1;
}
/* See if the issuer IDs match. */
i = ocsp_check_ids(sresp, &caid);
/* If ID mismatch or other error then return */
if (i <= 0)
return i;
signer = sk_X509_value(chain, 0);
/* Check to see if OCSP responder CA matches request CA */
if (sk_X509_num(chain) > 1) {
sca = sk_X509_value(chain, 1);
i = ocsp_match_issuerid(sca, caid, sresp);
if (i < 0)
return i;
if (i) {
/* We have a match, if extensions OK then success */
if (ocsp_check_delegated(signer))
return 1;
return 0;
}
}
/* Otherwise check if OCSP request signed directly by request CA */
return ocsp_match_issuerid(signer, caid, sresp);
}
/*
* Check the issuer certificate IDs for equality. If there is a mismatch with
* the same algorithm then there's no point trying to match any certificates
* against the issuer. If the issuer IDs all match then we just need to check
* equality against one of them.
*/
static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
{
OCSP_CERTID *tmpid, *cid;
int i, idcount;
idcount = sk_OCSP_SINGLERESP_num(sresp);
if (idcount <= 0) {
OCSPerr(OCSP_F_OCSP_CHECK_IDS,
OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
return -1;
}
cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
*ret = NULL;
for (i = 1; i < idcount; i++) {
tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
/* Check to see if IDs match */
if (OCSP_id_issuer_cmp(cid, tmpid)) {
/* If algorithm mismatch let caller deal with it */
if (OBJ_cmp(tmpid->hashAlgorithm.algorithm,
cid->hashAlgorithm.algorithm))
return 2;
/* Else mismatch */
return 0;
}
}
/* All IDs match: only need to check one ID */
*ret = cid;
return 1;
}
static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
STACK_OF(OCSP_SINGLERESP) *sresp)
{
/* If only one ID to match then do it */
if (cid) {
const EVP_MD *dgst;
X509_NAME *iname;
int mdlen;
unsigned char md[EVP_MAX_MD_SIZE];
if ((dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm))
== NULL) {
OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID,
OCSP_R_UNKNOWN_MESSAGE_DIGEST);
return -1;
}
mdlen = EVP_MD_size(dgst);
if (mdlen < 0)
return -1;
if ((cid->issuerNameHash.length != mdlen) ||
(cid->issuerKeyHash.length != mdlen))
return 0;
iname = X509_get_subject_name(cert);
if (!X509_NAME_digest(iname, dgst, md, NULL))
return -1;
if (memcmp(md, cid->issuerNameHash.data, mdlen))
return 0;
X509_pubkey_digest(cert, dgst, md, NULL);
if (memcmp(md, cid->issuerKeyHash.data, mdlen))
return 0;
return 1;
} else {
/* We have to match the whole lot */
int i, ret;
OCSP_CERTID *tmpid;
for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) {
tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
ret = ocsp_match_issuerid(cert, tmpid, NULL);
if (ret <= 0)
return ret;
}
return 1;
}
}
static int ocsp_check_delegated(X509 *x)
{
if ((X509_get_extension_flags(x) & EXFLAG_XKUSAGE)
&& (X509_get_extended_key_usage(x) & XKU_OCSP_SIGN))
return 1;
OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
return 0;
}
/*
* Verify an OCSP request. This is fortunately much easier than OCSP response
* verify. Just find the signers certificate and verify it against a given
* trust value.
*/
int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
X509_STORE *store, unsigned long flags)
{
X509 *signer;
X509_NAME *nm;
GENERAL_NAME *gen;
int ret = 0;
X509_STORE_CTX *ctx = X509_STORE_CTX_new();
if (ctx == NULL) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!req->optionalSignature) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
goto err;
}
gen = req->tbsRequest.requestorName;
if (!gen || gen->type != GEN_DIRNAME) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
goto err;
}
nm = gen->d.directoryName;
ret = ocsp_req_find_signer(&signer, req, nm, certs, flags);
if (ret <= 0) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
goto err;
}
if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
flags |= OCSP_NOVERIFY;
if (!(flags & OCSP_NOSIGS)) {
EVP_PKEY *skey;
skey = X509_get0_pubkey(signer);
ret = OCSP_REQUEST_verify(req, skey);
if (ret <= 0) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
goto err;
}
}
if (!(flags & OCSP_NOVERIFY)) {
int init_res;
if (flags & OCSP_NOCHAIN)
init_res = X509_STORE_CTX_init(ctx, store, signer, NULL);
else
init_res = X509_STORE_CTX_init(ctx, store, signer,
req->optionalSignature->certs);
if (!init_res) {
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, ERR_R_X509_LIB);
goto err;
}
X509_STORE_CTX_set_purpose(ctx, X509_PURPOSE_OCSP_HELPER);
X509_STORE_CTX_set_trust(ctx, X509_TRUST_OCSP_REQUEST);
ret = X509_verify_cert(ctx);
if (ret <= 0) {
ret = X509_STORE_CTX_get_error(ctx);
OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
OCSP_R_CERTIFICATE_VERIFY_ERROR);
ERR_add_error_data(2, "Verify error:",
X509_verify_cert_error_string(ret));
goto err;
}
}
ret = 1;
goto end;
err:
ret = 0;
end:
X509_STORE_CTX_free(ctx);
return ret;
}
static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
X509_NAME *nm, STACK_OF(X509) *certs,
unsigned long flags)
{
X509 *signer;
if (!(flags & OCSP_NOINTERN)) {
signer = X509_find_by_subject(req->optionalSignature->certs, nm);
if (signer) {
*psigner = signer;
return 1;
}
}
signer = X509_find_by_subject(certs, nm);
if (signer) {
*psigner = signer;
return 2;
}
return 0;
}