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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/ssh/lib/../kexecdhc.c	Lines:	0	90	0.0 %
Date:	2017-11-13	Branches:	0	62	0.0 %


/* $OpenBSD: kexecdhc.c,v 1.11 2017/05/30 14:23:52 markus Exp $ */
/*
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 * Copyright (c) 2010 Damien Miller.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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.
 */

#include <sys/types.h>

#include <stdio.h>
#include <string.h>
#include <signal.h>

#include <openssl/ecdh.h>

#include "sshkey.h"
#include "cipher.h"
#include "digest.h"
#include "kex.h"
#include "log.h"
#include "packet.h"
#include "dh.h"
#include "ssh2.h"
#include "dispatch.h"
#include "compat.h"
#include "ssherr.h"
#include "sshbuf.h"

static int input_kex_ecdh_reply(int, u_int32_t, struct ssh *);

int
kexecdh_client(struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	EC_KEY *client_key = NULL;
	const EC_GROUP *group;
	const EC_POINT *public_key;
	int r;

	if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if (EC_KEY_generate_key(client_key) != 1) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
	group = EC_KEY_get0_group(client_key);
	public_key = EC_KEY_get0_public_key(client_key);

	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_INIT)) != 0 ||
	    (r = sshpkt_put_ec(ssh, public_key, group)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		goto out;
	debug("sending SSH2_MSG_KEX_ECDH_INIT");

#ifdef DEBUG_KEXECDH
	fputs("client private key:\n", stderr);
	sshkey_dump_ec_key(client_key);
#endif
	kex->ec_client_key = client_key;
	kex->ec_group = group;
	client_key = NULL;	/* owned by the kex */

	debug("expecting SSH2_MSG_KEX_ECDH_REPLY");
	ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_REPLY, &input_kex_ecdh_reply);
	r = 0;
 out:
	if (client_key)
		EC_KEY_free(client_key);
	return r;
}

static int
input_kex_ecdh_reply(int type, u_int32_t seq, struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	const EC_GROUP *group;
	EC_POINT *server_public = NULL;
	EC_KEY *client_key;
	BIGNUM *shared_secret = NULL;
	struct sshkey *server_host_key = NULL;
	u_char *server_host_key_blob = NULL, *signature = NULL;
	u_char *kbuf = NULL;
	u_char hash[SSH_DIGEST_MAX_LENGTH];
	size_t slen, sbloblen;
	size_t klen = 0, hashlen;
	int r;

	if (kex->verify_host_key == NULL) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	group = kex->ec_group;
	client_key = kex->ec_client_key;

	/* hostkey */
	if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
	    &sbloblen)) != 0 ||
	    (r = sshkey_from_blob(server_host_key_blob, sbloblen,
	    &server_host_key)) != 0)
		goto out;
	if (server_host_key->type != kex->hostkey_type ||
	    (kex->hostkey_type == KEY_ECDSA &&
	    server_host_key->ecdsa_nid != kex->hostkey_nid)) {
		r = SSH_ERR_KEY_TYPE_MISMATCH;
		goto out;
	}
	if (kex->verify_host_key(server_host_key, ssh) == -1) {
		r = SSH_ERR_SIGNATURE_INVALID;
		goto out;
	}

	/* Q_S, server public key */
	/* signed H */
	if ((server_public = EC_POINT_new(group)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshpkt_get_ec(ssh, server_public, group)) != 0 ||
	    (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		goto out;

#ifdef DEBUG_KEXECDH
	fputs("server public key:\n", stderr);
	sshkey_dump_ec_point(group, server_public);
#endif
	if (sshkey_ec_validate_public(group, server_public) != 0) {
		sshpkt_disconnect(ssh, "invalid server public key");
		r = SSH_ERR_MESSAGE_INCOMPLETE;
		goto out;
	}

	klen = (EC_GROUP_get_degree(group) + 7) / 8;
	if ((kbuf = malloc(klen)) == NULL ||
	    (shared_secret = BN_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if (ECDH_compute_key(kbuf, klen, server_public,
	    client_key, NULL) != (int)klen ||
	    BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

#ifdef DEBUG_KEXECDH
	dump_digest("shared secret", kbuf, klen);
#endif
	/* calc and verify H */
	hashlen = sizeof(hash);
	if ((r = kex_ecdh_hash(
	    kex->hash_alg,
	    group,
	    kex->client_version_string,
	    kex->server_version_string,
	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
	    server_host_key_blob, sbloblen,
	    EC_KEY_get0_public_key(client_key),
	    server_public,
	    shared_secret,
	    hash, &hashlen)) != 0)
		goto out;

	if ((r = sshkey_verify(server_host_key, signature, slen, hash,
	    hashlen, ssh->compat)) != 0)
		goto out;

	/* save session id */
	if (kex->session_id == NULL) {
		kex->session_id_len = hashlen;
		kex->session_id = malloc(kex->session_id_len);
		if (kex->session_id == NULL) {
			r = SSH_ERR_ALLOC_FAIL;
			goto out;
		}
		memcpy(kex->session_id, hash, kex->session_id_len);
	}

	if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
		r = kex_send_newkeys(ssh);
 out:
	explicit_bzero(hash, sizeof(hash));
	if (kex->ec_client_key) {
		EC_KEY_free(kex->ec_client_key);
		kex->ec_client_key = NULL;
	}
	if (server_public)
		EC_POINT_clear_free(server_public);
	if (kbuf) {
		explicit_bzero(kbuf, klen);
		free(kbuf);
	}
	if (shared_secret)
		BN_clear_free(shared_secret);
	sshkey_free(server_host_key);
	free(server_host_key_blob);
	free(signature);
	return r;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: kexecdhc.c,v 1.11 2017/05/30 14:23:52 markus Exp $ */
2			/*
3			* Copyright (c) 2001 Markus Friedl. All rights reserved.
4			* Copyright (c) 2010 Damien Miller. All rights reserved.
5			*
6			* Redistribution and use in source and binary forms, with or without
7			* modification, are permitted provided that the following conditions
8			* are met:
9			* 1. Redistributions of source code must retain the above copyright
10			* notice, this list of conditions and the following disclaimer.
11			* 2. Redistributions in binary form must reproduce the above copyright
12			* notice, this list of conditions and the following disclaimer in the
13			* documentation and/or other materials provided with the distribution.
14			*
15			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25			*/
26
27			#include <sys/types.h>
28
29			#include <stdio.h>
30			#include <string.h>
31			#include <signal.h>
32
33			#include <openssl/ecdh.h>
34
35			#include "sshkey.h"
36			#include "cipher.h"
37			#include "digest.h"
38			#include "kex.h"
39			#include "log.h"
40			#include "packet.h"
41			#include "dh.h"
42			#include "ssh2.h"
43			#include "dispatch.h"
44			#include "compat.h"
45			#include "ssherr.h"
46			#include "sshbuf.h"
47
48			static int input_kex_ecdh_reply(int, u_int32_t, struct ssh *);
49
50			int
51			kexecdh_client(struct ssh *ssh)
52			{
53			struct kex *kex = ssh->kex;
54			EC_KEY *client_key = NULL;
55			const EC_GROUP *group;
56			const EC_POINT *public_key;
57			int r;
58
59			if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
60			r = SSH_ERR_ALLOC_FAIL;
61			goto out;
62			}
63			if (EC_KEY_generate_key(client_key) != 1) {
64			r = SSH_ERR_LIBCRYPTO_ERROR;
65			goto out;
66			}
67			group = EC_KEY_get0_group(client_key);
68			public_key = EC_KEY_get0_public_key(client_key);
69
70			if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_INIT)) != 0 \|\|
71			(r = sshpkt_put_ec(ssh, public_key, group)) != 0 \|\|
72			(r = sshpkt_send(ssh)) != 0)
73			goto out;
74			debug("sending SSH2_MSG_KEX_ECDH_INIT");
75
76			#ifdef DEBUG_KEXECDH
77			fputs("client private key:\n", stderr);
78			sshkey_dump_ec_key(client_key);
79			#endif
80			kex->ec_client_key = client_key;
81			kex->ec_group = group;
82			client_key = NULL; /* owned by the kex */
83
84			debug("expecting SSH2_MSG_KEX_ECDH_REPLY");
85			ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_REPLY, &input_kex_ecdh_reply);
86			r = 0;
87			out:
88			if (client_key)
89			EC_KEY_free(client_key);
90			return r;
91			}
92
93			static int
94			input_kex_ecdh_reply(int type, u_int32_t seq, struct ssh *ssh)
95			{
96			struct kex *kex = ssh->kex;
97			const EC_GROUP *group;
98			EC_POINT *server_public = NULL;
99			EC_KEY *client_key;
100			BIGNUM *shared_secret = NULL;
101			struct sshkey *server_host_key = NULL;
102			u_char server_host_key_blob = NULL, signature = NULL;
103			u_char *kbuf = NULL;
104			u_char hash[SSH_DIGEST_MAX_LENGTH];
105			size_t slen, sbloblen;
106			size_t klen = 0, hashlen;
107			int r;
108
109			if (kex->verify_host_key == NULL) {
110			r = SSH_ERR_INVALID_ARGUMENT;
111			goto out;
112			}
113			group = kex->ec_group;
114			client_key = kex->ec_client_key;
115
116			/* hostkey */
117			if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
118			&sbloblen)) != 0 \|\|
119			(r = sshkey_from_blob(server_host_key_blob, sbloblen,
120			&server_host_key)) != 0)
121			goto out;
122			if (server_host_key->type != kex->hostkey_type \|\|
123			(kex->hostkey_type == KEY_ECDSA &&
124			server_host_key->ecdsa_nid != kex->hostkey_nid)) {
125			r = SSH_ERR_KEY_TYPE_MISMATCH;
126			goto out;
127			}
128			if (kex->verify_host_key(server_host_key, ssh) == -1) {
129			r = SSH_ERR_SIGNATURE_INVALID;
130			goto out;
131			}
132
133			/* Q_S, server public key */
134			/* signed H */
135			if ((server_public = EC_POINT_new(group)) == NULL) {
136			r = SSH_ERR_ALLOC_FAIL;
137			goto out;
138			}
139			if ((r = sshpkt_get_ec(ssh, server_public, group)) != 0 \|\|
140			(r = sshpkt_get_string(ssh, &signature, &slen)) != 0 \|\|
141			(r = sshpkt_get_end(ssh)) != 0)
142			goto out;
143
144			#ifdef DEBUG_KEXECDH
145			fputs("server public key:\n", stderr);
146			sshkey_dump_ec_point(group, server_public);
147			#endif
148			if (sshkey_ec_validate_public(group, server_public) != 0) {
149			sshpkt_disconnect(ssh, "invalid server public key");
150			r = SSH_ERR_MESSAGE_INCOMPLETE;
151			goto out;
152			}
153
154			klen = (EC_GROUP_get_degree(group) + 7) / 8;
155			if ((kbuf = malloc(klen)) == NULL \|\|
156			(shared_secret = BN_new()) == NULL) {
157			r = SSH_ERR_ALLOC_FAIL;
158			goto out;
159			}
160			if (ECDH_compute_key(kbuf, klen, server_public,
161			client_key, NULL) != (int)klen \|\|
162			BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
163			r = SSH_ERR_LIBCRYPTO_ERROR;
164			goto out;
165			}
166
167			#ifdef DEBUG_KEXECDH
168			dump_digest("shared secret", kbuf, klen);
169			#endif
170			/* calc and verify H */
171			hashlen = sizeof(hash);
172			if ((r = kex_ecdh_hash(
173			kex->hash_alg,
174			group,
175			kex->client_version_string,
176			kex->server_version_string,
177			sshbuf_ptr(kex->my), sshbuf_len(kex->my),
178			sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
179			server_host_key_blob, sbloblen,
180			EC_KEY_get0_public_key(client_key),
181			server_public,
182			shared_secret,
183			hash, &hashlen)) != 0)
184			goto out;
185
186			if ((r = sshkey_verify(server_host_key, signature, slen, hash,
187			hashlen, ssh->compat)) != 0)
188			goto out;
189
190			/* save session id */
191			if (kex->session_id == NULL) {
192			kex->session_id_len = hashlen;
193			kex->session_id = malloc(kex->session_id_len);
194			if (kex->session_id == NULL) {
195			r = SSH_ERR_ALLOC_FAIL;
196			goto out;
197			}
198			memcpy(kex->session_id, hash, kex->session_id_len);
199			}
200
201			if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
202			r = kex_send_newkeys(ssh);
203			out:
204			explicit_bzero(hash, sizeof(hash));
205			if (kex->ec_client_key) {
206			EC_KEY_free(kex->ec_client_key);
207			kex->ec_client_key = NULL;
208			}
209			if (server_public)
210			EC_POINT_clear_free(server_public);
211			if (kbuf) {
212			explicit_bzero(kbuf, klen);
213			free(kbuf);
214			}
215			if (shared_secret)
216			BN_clear_free(shared_secret);
217			sshkey_free(server_host_key);
218			free(server_host_key_blob);
219			free(signature);
220			return r;
221			}