GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/ssh/lib/../kexc25519s.c Lines: 0 63 0.0 %
Date: 2017-11-13 Branches: 0 38 0.0 %

Line Branch Exec Source
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/* $OpenBSD: kexc25519s.c,v 1.11 2017/05/31 04:19:28 djm Exp $ */
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/*
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 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
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 * Copyright (c) 2010 Damien Miller.  All rights reserved.
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 * Copyright (c) 2013 Aris Adamantiadis.  All rights reserved.
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 *
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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 <sys/types.h>
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#include <stdio.h>
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#include <string.h>
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#include <signal.h>
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#include "sshkey.h"
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#include "cipher.h"
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#include "digest.h"
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#include "kex.h"
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#include "log.h"
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#include "packet.h"
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#include "ssh2.h"
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#include "sshbuf.h"
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#include "ssherr.h"
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static int input_kex_c25519_init(int, u_int32_t, struct ssh *);
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int
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kexc25519_server(struct ssh *ssh)
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{
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	debug("expecting SSH2_MSG_KEX_ECDH_INIT");
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	ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_INIT, &input_kex_c25519_init);
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	return 0;
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}
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static int
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input_kex_c25519_init(int type, u_int32_t seq, struct ssh *ssh)
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{
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	struct kex *kex = ssh->kex;
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	struct sshkey *server_host_private, *server_host_public;
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	struct sshbuf *shared_secret = NULL;
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	u_char *server_host_key_blob = NULL, *signature = NULL;
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	u_char server_key[CURVE25519_SIZE];
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	u_char *client_pubkey = NULL;
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	u_char server_pubkey[CURVE25519_SIZE];
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	u_char hash[SSH_DIGEST_MAX_LENGTH];
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	size_t slen, pklen, sbloblen, hashlen;
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	int r;
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	/* generate private key */
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	kexc25519_keygen(server_key, server_pubkey);
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#ifdef DEBUG_KEXECDH
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	dump_digest("server private key:", server_key, sizeof(server_key));
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#endif
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	if (kex->load_host_public_key == NULL ||
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	    kex->load_host_private_key == NULL) {
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		r = SSH_ERR_INVALID_ARGUMENT;
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		goto out;
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	}
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	server_host_public = kex->load_host_public_key(kex->hostkey_type,
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	    kex->hostkey_nid, ssh);
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	server_host_private = kex->load_host_private_key(kex->hostkey_type,
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	    kex->hostkey_nid, ssh);
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	if (server_host_public == NULL) {
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		r = SSH_ERR_NO_HOSTKEY_LOADED;
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		goto out;
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	}
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	if ((r = sshpkt_get_string(ssh, &client_pubkey, &pklen)) != 0 ||
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	    (r = sshpkt_get_end(ssh)) != 0)
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		goto out;
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	if (pklen != CURVE25519_SIZE) {
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		r = SSH_ERR_SIGNATURE_INVALID;
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		goto out;
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	}
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#ifdef DEBUG_KEXECDH
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	dump_digest("client public key:", client_pubkey, CURVE25519_SIZE);
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#endif
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	if ((shared_secret = sshbuf_new()) == NULL) {
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		r = SSH_ERR_ALLOC_FAIL;
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		goto out;
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	}
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	if ((r = kexc25519_shared_key(server_key, client_pubkey,
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	    shared_secret)) < 0)
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		goto out;
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	/* calc H */
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	if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
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	    &sbloblen)) != 0)
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		goto out;
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	hashlen = sizeof(hash);
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	if ((r = kex_c25519_hash(
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	    kex->hash_alg,
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	    kex->client_version_string,
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	    kex->server_version_string,
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	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
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	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
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	    server_host_key_blob, sbloblen,
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	    client_pubkey,
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	    server_pubkey,
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	    sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
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	    hash, &hashlen)) < 0)
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		goto out;
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	/* save session id := H */
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	if (kex->session_id == NULL) {
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		kex->session_id_len = hashlen;
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		kex->session_id = malloc(kex->session_id_len);
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		if (kex->session_id == NULL) {
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			r = SSH_ERR_ALLOC_FAIL;
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			goto out;
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		}
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		memcpy(kex->session_id, hash, kex->session_id_len);
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	}
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	/* sign H */
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	if ((r = kex->sign(server_host_private, server_host_public, &signature,
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	     &slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
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		goto out;
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	/* send server hostkey, ECDH pubkey 'Q_S' and signed H */
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	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_REPLY)) != 0 ||
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	    (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
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	    (r = sshpkt_put_string(ssh, server_pubkey, sizeof(server_pubkey))) != 0 ||
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	    (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
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	    (r = sshpkt_send(ssh)) != 0)
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		goto out;
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	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
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		r = kex_send_newkeys(ssh);
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out:
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	explicit_bzero(hash, sizeof(hash));
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	explicit_bzero(server_key, sizeof(server_key));
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	free(server_host_key_blob);
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	free(signature);
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	free(client_pubkey);
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	sshbuf_free(shared_secret);
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	return r;
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}