2014-01-30 10:56:49 +00:00
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/* $OpenBSD: ssh-ecdsa.c,v 1.8 2014/01/09 23:20:00 djm Exp $ */
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2011-02-17 11:47:40 +00:00
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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* Copyright (c) 2010 Damien Miller. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#ifdef OPENSSL_HAS_ECC
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#include <sys/types.h>
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#include <openssl/bn.h>
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#include <openssl/ec.h>
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#include <openssl/ecdsa.h>
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#include <openssl/evp.h>
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#include <string.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "compat.h"
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#include "log.h"
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#include "key.h"
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2014-01-30 10:56:49 +00:00
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#include "digest.h"
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2011-02-17 11:47:40 +00:00
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int
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ssh_ecdsa_sign(const Key *key, u_char **sigp, u_int *lenp,
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const u_char *data, u_int datalen)
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{
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ECDSA_SIG *sig;
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2014-01-30 10:56:49 +00:00
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int hash_alg;
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u_char digest[SSH_DIGEST_MAX_LENGTH];
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2011-02-17 11:47:40 +00:00
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u_int len, dlen;
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Buffer b, bb;
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2014-01-30 10:56:49 +00:00
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if (key == NULL || key_type_plain(key->type) != KEY_ECDSA ||
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key->ecdsa == NULL) {
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2011-02-17 11:47:40 +00:00
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error("%s: no ECDSA key", __func__);
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return -1;
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}
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2014-01-30 10:56:49 +00:00
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hash_alg = key_ec_nid_to_hash_alg(key->ecdsa_nid);
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if ((dlen = ssh_digest_bytes(hash_alg)) == 0) {
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error("%s: bad hash algorithm %d", __func__, hash_alg);
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return -1;
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}
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if (ssh_digest_memory(hash_alg, data, datalen,
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digest, sizeof(digest)) != 0) {
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error("%s: digest_memory failed", __func__);
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return -1;
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}
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2011-02-17 11:47:40 +00:00
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sig = ECDSA_do_sign(digest, dlen, key->ecdsa);
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memset(digest, 'd', sizeof(digest));
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if (sig == NULL) {
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error("%s: sign failed", __func__);
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return -1;
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}
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buffer_init(&bb);
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buffer_put_bignum2(&bb, sig->r);
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buffer_put_bignum2(&bb, sig->s);
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ECDSA_SIG_free(sig);
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buffer_init(&b);
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buffer_put_cstring(&b, key_ssh_name_plain(key));
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buffer_put_string(&b, buffer_ptr(&bb), buffer_len(&bb));
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buffer_free(&bb);
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len = buffer_len(&b);
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if (lenp != NULL)
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*lenp = len;
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if (sigp != NULL) {
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*sigp = xmalloc(len);
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memcpy(*sigp, buffer_ptr(&b), len);
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}
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buffer_free(&b);
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return 0;
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}
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int
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ssh_ecdsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
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const u_char *data, u_int datalen)
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{
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ECDSA_SIG *sig;
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2014-01-30 10:56:49 +00:00
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int hash_alg;
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u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob;
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2011-02-17 11:47:40 +00:00
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u_int len, dlen;
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int rlen, ret;
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Buffer b, bb;
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char *ktype;
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2014-01-30 10:56:49 +00:00
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if (key == NULL || key_type_plain(key->type) != KEY_ECDSA ||
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key->ecdsa == NULL) {
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2011-02-17 11:47:40 +00:00
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error("%s: no ECDSA key", __func__);
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return -1;
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}
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/* fetch signature */
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buffer_init(&b);
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buffer_append(&b, signature, signaturelen);
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ktype = buffer_get_string(&b, NULL);
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if (strcmp(key_ssh_name_plain(key), ktype) != 0) {
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error("%s: cannot handle type %s", __func__, ktype);
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buffer_free(&b);
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2013-09-18 17:27:38 +00:00
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free(ktype);
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2011-02-17 11:47:40 +00:00
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return -1;
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}
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2013-09-18 17:27:38 +00:00
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free(ktype);
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2011-02-17 11:47:40 +00:00
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sigblob = buffer_get_string(&b, &len);
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rlen = buffer_len(&b);
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buffer_free(&b);
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if (rlen != 0) {
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error("%s: remaining bytes in signature %d", __func__, rlen);
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2013-09-18 17:27:38 +00:00
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free(sigblob);
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2011-02-17 11:47:40 +00:00
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return -1;
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}
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/* parse signature */
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if ((sig = ECDSA_SIG_new()) == NULL)
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fatal("%s: ECDSA_SIG_new failed", __func__);
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if ((sig->r = BN_new()) == NULL ||
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(sig->s = BN_new()) == NULL)
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fatal("%s: BN_new failed", __func__);
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buffer_init(&bb);
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buffer_append(&bb, sigblob, len);
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buffer_get_bignum2(&bb, sig->r);
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buffer_get_bignum2(&bb, sig->s);
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if (buffer_len(&bb) != 0)
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fatal("%s: remaining bytes in inner sigblob", __func__);
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2012-08-29 15:46:01 +00:00
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buffer_free(&bb);
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2011-02-17 11:47:40 +00:00
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/* clean up */
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memset(sigblob, 0, len);
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2013-09-18 17:27:38 +00:00
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free(sigblob);
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2011-02-17 11:47:40 +00:00
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/* hash the data */
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2014-01-30 10:56:49 +00:00
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hash_alg = key_ec_nid_to_hash_alg(key->ecdsa_nid);
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if ((dlen = ssh_digest_bytes(hash_alg)) == 0) {
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error("%s: bad hash algorithm %d", __func__, hash_alg);
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return -1;
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}
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if (ssh_digest_memory(hash_alg, data, datalen,
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digest, sizeof(digest)) != 0) {
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error("%s: digest_memory failed", __func__);
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return -1;
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}
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2011-02-17 11:47:40 +00:00
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ret = ECDSA_do_verify(digest, dlen, sig, key->ecdsa);
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memset(digest, 'd', sizeof(digest));
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ECDSA_SIG_free(sig);
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debug("%s: signature %s", __func__,
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ret == 1 ? "correct" : ret == 0 ? "incorrect" : "error");
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return ret;
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}
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#endif /* OPENSSL_HAS_ECC */
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