2018-05-06 12:27:04 +00:00
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/* $OpenBSD: ssh-ecdsa.c,v 1.14 2018/02/07 02:06:51 jsing 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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2015-07-02 13:15:34 +00:00
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#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
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2011-02-17 11:47:40 +00:00
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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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2015-01-05 16:09:55 +00:00
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#include "sshbuf.h"
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#include "ssherr.h"
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2014-01-30 10:56:49 +00:00
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#include "digest.h"
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2015-01-05 16:09:55 +00:00
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#define SSHKEY_INTERNAL
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#include "sshkey.h"
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2011-02-17 11:47:40 +00:00
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2015-01-05 16:09:55 +00:00
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/* ARGSUSED */
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2011-02-17 11:47:40 +00:00
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int
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2015-01-05 16:09:55 +00:00
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ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
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const u_char *data, size_t datalen, u_int compat)
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2011-02-17 11:47:40 +00:00
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{
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2015-01-05 16:09:55 +00:00
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ECDSA_SIG *sig = NULL;
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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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2015-01-05 16:09:55 +00:00
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size_t len, dlen;
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struct sshbuf *b = NULL, *bb = NULL;
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int ret = SSH_ERR_INTERNAL_ERROR;
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2011-02-17 11:47:40 +00:00
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2015-01-05 16:09:55 +00:00
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if (lenp != NULL)
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*lenp = 0;
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if (sigp != NULL)
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*sigp = NULL;
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if (key == NULL || key->ecdsa == NULL ||
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sshkey_type_plain(key->type) != KEY_ECDSA)
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return SSH_ERR_INVALID_ARGUMENT;
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if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
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(dlen = ssh_digest_bytes(hash_alg)) == 0)
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return SSH_ERR_INTERNAL_ERROR;
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if ((ret = ssh_digest_memory(hash_alg, data, datalen,
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digest, sizeof(digest))) != 0)
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goto out;
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if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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2011-02-17 11:47:40 +00:00
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}
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2014-01-30 10:56:49 +00:00
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2015-01-05 16:09:55 +00:00
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if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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2014-01-30 10:56:49 +00:00
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}
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2015-01-05 16:09:55 +00:00
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if ((ret = sshbuf_put_bignum2(bb, sig->r)) != 0 ||
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(ret = sshbuf_put_bignum2(bb, sig->s)) != 0)
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goto out;
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if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 ||
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(ret = sshbuf_put_stringb(b, bb)) != 0)
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goto out;
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len = sshbuf_len(b);
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if (sigp != NULL) {
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if ((*sigp = malloc(len)) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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memcpy(*sigp, sshbuf_ptr(b), len);
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2011-02-17 11:47:40 +00:00
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}
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if (lenp != NULL)
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*lenp = len;
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2015-01-05 16:09:55 +00:00
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ret = 0;
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out:
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explicit_bzero(digest, sizeof(digest));
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2016-03-10 20:10:25 +00:00
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sshbuf_free(b);
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sshbuf_free(bb);
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2018-05-06 12:27:04 +00:00
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ECDSA_SIG_free(sig);
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2015-01-05 16:09:55 +00:00
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return ret;
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2011-02-17 11:47:40 +00:00
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}
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2015-01-05 16:09:55 +00:00
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/* ARGSUSED */
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2011-02-17 11:47:40 +00:00
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int
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2015-01-05 16:09:55 +00:00
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ssh_ecdsa_verify(const struct sshkey *key,
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const u_char *signature, size_t signaturelen,
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const u_char *data, size_t datalen, u_int compat)
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2011-02-17 11:47:40 +00:00
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{
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2015-01-05 16:09:55 +00:00
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ECDSA_SIG *sig = NULL;
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2014-01-30 10:56:49 +00:00
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int hash_alg;
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2015-01-05 16:09:55 +00:00
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u_char digest[SSH_DIGEST_MAX_LENGTH];
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size_t dlen;
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int ret = SSH_ERR_INTERNAL_ERROR;
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struct sshbuf *b = NULL, *sigbuf = NULL;
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char *ktype = NULL;
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if (key == NULL || key->ecdsa == NULL ||
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2017-01-31 12:29:48 +00:00
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sshkey_type_plain(key->type) != KEY_ECDSA ||
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signature == NULL || signaturelen == 0)
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2015-01-05 16:09:55 +00:00
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return SSH_ERR_INVALID_ARGUMENT;
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if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
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(dlen = ssh_digest_bytes(hash_alg)) == 0)
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return SSH_ERR_INTERNAL_ERROR;
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2011-02-17 11:47:40 +00:00
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/* fetch signature */
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2015-01-05 16:09:55 +00:00
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if ((b = sshbuf_from(signature, signaturelen)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
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sshbuf_froms(b, &sigbuf) != 0) {
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ret = SSH_ERR_INVALID_FORMAT;
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goto out;
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2011-02-17 11:47:40 +00:00
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}
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2015-01-05 16:09:55 +00:00
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if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
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ret = SSH_ERR_KEY_TYPE_MISMATCH;
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goto out;
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}
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if (sshbuf_len(b) != 0) {
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ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
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goto out;
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2011-02-17 11:47:40 +00:00
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}
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/* parse signature */
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2015-01-05 16:09:55 +00:00
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if ((sig = ECDSA_SIG_new()) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if (sshbuf_get_bignum2(sigbuf, sig->r) != 0 ||
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sshbuf_get_bignum2(sigbuf, sig->s) != 0) {
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ret = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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if (sshbuf_len(sigbuf) != 0) {
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ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
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goto out;
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2014-01-30 10:56:49 +00:00
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}
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2015-01-05 16:09:55 +00:00
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if ((ret = ssh_digest_memory(hash_alg, data, datalen,
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digest, sizeof(digest))) != 0)
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goto out;
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switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) {
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case 1:
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ret = 0;
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break;
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case 0:
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ret = SSH_ERR_SIGNATURE_INVALID;
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goto out;
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default:
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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2014-01-30 10:56:49 +00:00
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}
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2011-02-17 11:47:40 +00:00
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2015-01-05 16:09:55 +00:00
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out:
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2014-03-22 15:23:38 +00:00
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explicit_bzero(digest, sizeof(digest));
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2016-03-10 20:10:25 +00:00
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sshbuf_free(sigbuf);
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sshbuf_free(b);
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2018-05-06 12:27:04 +00:00
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ECDSA_SIG_free(sig);
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2015-01-05 16:09:55 +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 ret;
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}
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2015-07-02 13:15:34 +00:00
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#endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */
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