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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/ssh/lib/../kexdhs.c	Lines:	0	86	0.0 %
Date:	2017-11-13	Branches:	0	60	0.0 %


/* $OpenBSD: kexdhs.c,v 1.25 2017/05/30 14:23:52 markus Exp $ */
/*
 * Copyright (c) 2001 Markus Friedl.  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 <string.h>
#include <signal.h>

#include <openssl/dh.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_dh_init(int, u_int32_t, struct ssh *);

int
kexdh_server(struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	int r;

	/* generate server DH public key */
	switch (kex->kex_type) {
	case KEX_DH_GRP1_SHA1:
		kex->dh = dh_new_group1();
		break;
	case KEX_DH_GRP14_SHA1:
	case KEX_DH_GRP14_SHA256:
		kex->dh = dh_new_group14();
		break;
	case KEX_DH_GRP16_SHA512:
		kex->dh = dh_new_group16();
		break;
	case KEX_DH_GRP18_SHA512:
		kex->dh = dh_new_group18();
		break;
	default:
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	if (kex->dh == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
		goto out;

	debug("expecting SSH2_MSG_KEXDH_INIT");
	ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init);
	r = 0;
 out:
	return r;
}

int
input_kex_dh_init(int type, u_int32_t seq, struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
	struct sshkey *server_host_public, *server_host_private;
	u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
	u_char hash[SSH_DIGEST_MAX_LENGTH];
	size_t sbloblen, slen;
	size_t klen = 0, hashlen;
	int kout, r;

	if (kex->load_host_public_key == NULL ||
	    kex->load_host_private_key == NULL) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	server_host_public = kex->load_host_public_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	server_host_private = kex->load_host_private_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	if (server_host_public == NULL) {
		r = SSH_ERR_NO_HOSTKEY_LOADED;
		goto out;
	}

	/* key, cert */
	if ((dh_client_pub = BN_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		goto out;

#ifdef DEBUG_KEXDH
	fprintf(stderr, "dh_client_pub= ");
	BN_print_fp(stderr, dh_client_pub);
	fprintf(stderr, "\n");
	debug("bits %d", BN_num_bits(dh_client_pub));
#endif

#ifdef DEBUG_KEXDH
	DHparams_print_fp(stderr, kex->dh);
	fprintf(stderr, "pub= ");
	BN_print_fp(stderr, kex->dh->pub_key);
	fprintf(stderr, "\n");
#endif
	if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
		sshpkt_disconnect(ssh, "bad client public DH value");
		r = SSH_ERR_MESSAGE_INCOMPLETE;
		goto out;
	}

	klen = DH_size(kex->dh);
	if ((kbuf = malloc(klen)) == NULL ||
	    (shared_secret = BN_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
	    BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
#ifdef DEBUG_KEXDH
	dump_digest("shared secret", kbuf, kout);
#endif
	if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
	    &sbloblen)) != 0)
		goto out;
	/* calc H */
	hashlen = sizeof(hash);
	if ((r = kex_dh_hash(
	    kex->hash_alg,
	    kex->client_version_string,
	    kex->server_version_string,
	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
	    server_host_key_blob, sbloblen,
	    dh_client_pub,
	    kex->dh->pub_key,
	    shared_secret,
	    hash, &hashlen)) != 0)
		goto out;

	/* save session id := H */
	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);
	}

	/* sign H */
	if ((r = kex->sign(server_host_private, server_host_public, &signature,
	     &slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
		goto out;

	/* destroy_sensitive_data(); */

	/* send server hostkey, DH pubkey 'f' and singed H */
	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 ||
	    (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
	    (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 ||	/* f */
	    (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		goto out;

	if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
		r = kex_send_newkeys(ssh);
 out:
	explicit_bzero(hash, sizeof(hash));
	DH_free(kex->dh);
	kex->dh = NULL;
	if (dh_client_pub)
		BN_clear_free(dh_client_pub);
	if (kbuf) {
		explicit_bzero(kbuf, klen);
		free(kbuf);
	}
	if (shared_secret)
		BN_clear_free(shared_secret);
	free(server_host_key_blob);
	free(signature);
	return r;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: kexdhs.c,v 1.25 2017/05/30 14:23:52 markus Exp $ */
2			/*
3			* Copyright (c) 2001 Markus Friedl. All rights reserved.
4			*
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions
7			* are met:
8			* 1. Redistributions of source code must retain the above copyright
9			* notice, this list of conditions and the following disclaimer.
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13			*
14			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24			*/
25
26
27			#include <sys/types.h>
28			#include <string.h>
29			#include <signal.h>
30
31			#include <openssl/dh.h>
32
33			#include "sshkey.h"
34			#include "cipher.h"
35			#include "digest.h"
36			#include "kex.h"
37			#include "log.h"
38			#include "packet.h"
39			#include "dh.h"
40			#include "ssh2.h"
41
42			#include "dispatch.h"
43			#include "compat.h"
44			#include "ssherr.h"
45			#include "sshbuf.h"
46
47			static int input_kex_dh_init(int, u_int32_t, struct ssh *);
48
49			int
50			kexdh_server(struct ssh *ssh)
51			{
52			struct kex *kex = ssh->kex;
53			int r;
54
55			/* generate server DH public key */
56			switch (kex->kex_type) {
57			case KEX_DH_GRP1_SHA1:
58			kex->dh = dh_new_group1();
59			break;
60			case KEX_DH_GRP14_SHA1:
61			case KEX_DH_GRP14_SHA256:
62			kex->dh = dh_new_group14();
63			break;
64			case KEX_DH_GRP16_SHA512:
65			kex->dh = dh_new_group16();
66			break;
67			case KEX_DH_GRP18_SHA512:
68			kex->dh = dh_new_group18();
69			break;
70			default:
71			r = SSH_ERR_INVALID_ARGUMENT;
72			goto out;
73			}
74			if (kex->dh == NULL) {
75			r = SSH_ERR_ALLOC_FAIL;
76			goto out;
77			}
78			if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
79			goto out;
80
81			debug("expecting SSH2_MSG_KEXDH_INIT");
82			ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init);
83			r = 0;
84			out:
85			return r;
86			}
87
88			int
89			input_kex_dh_init(int type, u_int32_t seq, struct ssh *ssh)
90			{
91			struct kex *kex = ssh->kex;
92			BIGNUM shared_secret = NULL, dh_client_pub = NULL;
93			struct sshkey server_host_public, server_host_private;
94			u_char kbuf = NULL, signature = NULL, *server_host_key_blob = NULL;
95			u_char hash[SSH_DIGEST_MAX_LENGTH];
96			size_t sbloblen, slen;
97			size_t klen = 0, hashlen;
98			int kout, r;
99
100			if (kex->load_host_public_key == NULL \|\|
101			kex->load_host_private_key == NULL) {
102			r = SSH_ERR_INVALID_ARGUMENT;
103			goto out;
104			}
105			server_host_public = kex->load_host_public_key(kex->hostkey_type,
106			kex->hostkey_nid, ssh);
107			server_host_private = kex->load_host_private_key(kex->hostkey_type,
108			kex->hostkey_nid, ssh);
109			if (server_host_public == NULL) {
110			r = SSH_ERR_NO_HOSTKEY_LOADED;
111			goto out;
112			}
113
114			/* key, cert */
115			if ((dh_client_pub = BN_new()) == NULL) {
116			r = SSH_ERR_ALLOC_FAIL;
117			goto out;
118			}
119			if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 \|\|
120			(r = sshpkt_get_end(ssh)) != 0)
121			goto out;
122
123			#ifdef DEBUG_KEXDH
124			fprintf(stderr, "dh_client_pub= ");
125			BN_print_fp(stderr, dh_client_pub);
126			fprintf(stderr, "\n");
127			debug("bits %d", BN_num_bits(dh_client_pub));
128			#endif
129
130			#ifdef DEBUG_KEXDH
131			DHparams_print_fp(stderr, kex->dh);
132			fprintf(stderr, "pub= ");
133			BN_print_fp(stderr, kex->dh->pub_key);
134			fprintf(stderr, "\n");
135			#endif
136			if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
137			sshpkt_disconnect(ssh, "bad client public DH value");
138			r = SSH_ERR_MESSAGE_INCOMPLETE;
139			goto out;
140			}
141
142			klen = DH_size(kex->dh);
143			if ((kbuf = malloc(klen)) == NULL \|\|
144			(shared_secret = BN_new()) == NULL) {
145			r = SSH_ERR_ALLOC_FAIL;
146			goto out;
147			}
148			if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 \|\|
149			BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
150			r = SSH_ERR_LIBCRYPTO_ERROR;
151			goto out;
152			}
153			#ifdef DEBUG_KEXDH
154			dump_digest("shared secret", kbuf, kout);
155			#endif
156			if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
157			&sbloblen)) != 0)
158			goto out;
159			/* calc H */
160			hashlen = sizeof(hash);
161			if ((r = kex_dh_hash(
162			kex->hash_alg,
163			kex->client_version_string,
164			kex->server_version_string,
165			sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
166			sshbuf_ptr(kex->my), sshbuf_len(kex->my),
167			server_host_key_blob, sbloblen,
168			dh_client_pub,
169			kex->dh->pub_key,
170			shared_secret,
171			hash, &hashlen)) != 0)
172			goto out;
173
174			/* save session id := H */
175			if (kex->session_id == NULL) {
176			kex->session_id_len = hashlen;
177			kex->session_id = malloc(kex->session_id_len);
178			if (kex->session_id == NULL) {
179			r = SSH_ERR_ALLOC_FAIL;
180			goto out;
181			}
182			memcpy(kex->session_id, hash, kex->session_id_len);
183			}
184
185			/* sign H */
186			if ((r = kex->sign(server_host_private, server_host_public, &signature,
187			&slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
188			goto out;
189
190			/* destroy_sensitive_data(); */
191
192			/* send server hostkey, DH pubkey 'f' and singed H */
193			if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 \|\|
194			(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 \|\|
195			(r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 \|\| /* f */
196			(r = sshpkt_put_string(ssh, signature, slen)) != 0 \|\|
197			(r = sshpkt_send(ssh)) != 0)
198			goto out;
199
200			if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
201			r = kex_send_newkeys(ssh);
202			out:
203			explicit_bzero(hash, sizeof(hash));
204			DH_free(kex->dh);
205			kex->dh = NULL;
206			if (dh_client_pub)
207			BN_clear_free(dh_client_pub);
208			if (kbuf) {
209			explicit_bzero(kbuf, klen);
210			free(kbuf);
211			}
212			if (shared_secret)
213			BN_clear_free(shared_secret);
214			free(server_host_key_blob);
215			free(signature);
216			return r;
217			}