Annotation of src/usr.bin/ssh/kexdhc.c, Revision 1.19
1.19 ! djm 1: /* $OpenBSD: kexdhc.c,v 1.18 2015/01/26 06:10:03 djm Exp $ */
1.1 markus 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:
1.9 deraadt 26: #include <sys/types.h>
1.12 djm 27:
28: #include <openssl/dh.h>
1.7 stevesk 29:
1.8 stevesk 30: #include <stdio.h>
1.7 stevesk 31: #include <string.h>
1.9 deraadt 32: #include <signal.h>
1.1 markus 33:
1.17 markus 34: #include "sshkey.h"
1.9 deraadt 35: #include "cipher.h"
1.17 markus 36: #include "digest.h"
1.1 markus 37: #include "kex.h"
38: #include "log.h"
39: #include "packet.h"
40: #include "dh.h"
41: #include "ssh2.h"
1.17 markus 42: #include "dispatch.h"
43: #include "compat.h"
44: #include "ssherr.h"
45: #include "sshbuf.h"
1.1 markus 46:
1.17 markus 47: static int input_kex_dh(int, u_int32_t, void *);
48:
49: int
50: kexdh_client(struct ssh *ssh)
1.1 markus 51: {
1.17 markus 52: struct kex *kex = ssh->kex;
53: int r;
1.1 markus 54:
55: /* generate and send 'e', client DH public key */
1.2 djm 56: switch (kex->kex_type) {
57: case KEX_DH_GRP1_SHA1:
1.17 markus 58: kex->dh = dh_new_group1();
1.2 djm 59: break;
60: case KEX_DH_GRP14_SHA1:
1.19 ! djm 61: case KEX_DH_GRP14_SHA256:
1.17 markus 62: kex->dh = dh_new_group14();
1.2 djm 63: break;
1.19 ! djm 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;
1.2 djm 70: default:
1.17 markus 71: r = SSH_ERR_INVALID_ARGUMENT;
72: goto out;
73: }
74: if (kex->dh == NULL) {
75: r = SSH_ERR_ALLOC_FAIL;
76: goto out;
1.2 djm 77: }
1.1 markus 78: debug("sending SSH2_MSG_KEXDH_INIT");
1.17 markus 79: if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0 ||
80: (r = sshpkt_start(ssh, SSH2_MSG_KEXDH_INIT)) != 0 ||
81: (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 ||
82: (r = sshpkt_send(ssh)) != 0)
83: goto out;
1.1 markus 84: #ifdef DEBUG_KEXDH
1.17 markus 85: DHparams_print_fp(stderr, kex->dh);
1.1 markus 86: fprintf(stderr, "pub= ");
1.17 markus 87: BN_print_fp(stderr, kex->dh->pub_key);
1.1 markus 88: fprintf(stderr, "\n");
89: #endif
90: debug("expecting SSH2_MSG_KEXDH_REPLY");
1.17 markus 91: ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_REPLY, &input_kex_dh);
92: r = 0;
93: out:
94: return r;
95: }
1.1 markus 96:
1.17 markus 97: static int
98: input_kex_dh(int type, u_int32_t seq, void *ctxt)
99: {
100: struct ssh *ssh = ctxt;
101: struct kex *kex = ssh->kex;
102: BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
103: struct sshkey *server_host_key = NULL;
104: u_char *kbuf = NULL, *server_host_key_blob = NULL, *signature = NULL;
105: u_char hash[SSH_DIGEST_MAX_LENGTH];
106: size_t klen = 0, slen, sbloblen, hashlen;
107: int kout, r;
108:
109: if (kex->verify_host_key == NULL) {
110: r = SSH_ERR_INVALID_ARGUMENT;
111: goto out;
112: }
1.1 markus 113: /* key, cert */
1.17 markus 114: if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
115: &sbloblen)) != 0 ||
116: (r = sshkey_from_blob(server_host_key_blob, sbloblen,
117: &server_host_key)) != 0)
118: goto out;
1.18 djm 119: if (server_host_key->type != kex->hostkey_type ||
120: (kex->hostkey_type == KEY_ECDSA &&
121: server_host_key->ecdsa_nid != kex->hostkey_nid)) {
1.17 markus 122: r = SSH_ERR_KEY_TYPE_MISMATCH;
123: goto out;
124: }
125: if (kex->verify_host_key(server_host_key, ssh) == -1) {
126: r = SSH_ERR_SIGNATURE_INVALID;
127: goto out;
128: }
1.6 miod 129: /* DH parameter f, server public DH key */
1.17 markus 130: if ((dh_server_pub = BN_new()) == NULL) {
131: r = SSH_ERR_ALLOC_FAIL;
132: goto out;
133: }
134: /* signed H */
135: if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 ||
136: (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
137: (r = sshpkt_get_end(ssh)) != 0)
138: goto out;
1.1 markus 139: #ifdef DEBUG_KEXDH
140: fprintf(stderr, "dh_server_pub= ");
141: BN_print_fp(stderr, dh_server_pub);
142: fprintf(stderr, "\n");
143: debug("bits %d", BN_num_bits(dh_server_pub));
144: #endif
1.17 markus 145: if (!dh_pub_is_valid(kex->dh, dh_server_pub)) {
146: sshpkt_disconnect(ssh, "bad server public DH value");
147: r = SSH_ERR_MESSAGE_INCOMPLETE;
148: goto out;
149: }
1.1 markus 150:
1.17 markus 151: klen = DH_size(kex->dh);
152: if ((kbuf = malloc(klen)) == NULL ||
153: (shared_secret = BN_new()) == NULL) {
154: r = SSH_ERR_ALLOC_FAIL;
155: goto out;
156: }
157: if ((kout = DH_compute_key(kbuf, dh_server_pub, kex->dh)) < 0 ||
158: BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
159: r = SSH_ERR_LIBCRYPTO_ERROR;
160: goto out;
161: }
1.1 markus 162: #ifdef DEBUG_KEXDH
163: dump_digest("shared secret", kbuf, kout);
164: #endif
165:
166: /* calc and verify H */
1.17 markus 167: hashlen = sizeof(hash);
168: if ((r = kex_dh_hash(
1.19 ! djm 169: kex->hash_alg,
1.1 markus 170: kex->client_version_string,
171: kex->server_version_string,
1.17 markus 172: sshbuf_ptr(kex->my), sshbuf_len(kex->my),
173: sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
1.1 markus 174: server_host_key_blob, sbloblen,
1.17 markus 175: kex->dh->pub_key,
1.1 markus 176: dh_server_pub,
1.3 djm 177: shared_secret,
1.17 markus 178: hash, &hashlen)) != 0)
179: goto out;
1.1 markus 180:
1.17 markus 181: if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen,
182: ssh->compat)) != 0)
183: goto out;
1.1 markus 184:
185: /* save session id */
186: if (kex->session_id == NULL) {
1.3 djm 187: kex->session_id_len = hashlen;
1.17 markus 188: kex->session_id = malloc(kex->session_id_len);
189: if (kex->session_id == NULL) {
190: r = SSH_ERR_ALLOC_FAIL;
191: goto out;
192: }
1.1 markus 193: memcpy(kex->session_id, hash, kex->session_id_len);
194: }
195:
1.17 markus 196: if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
197: r = kex_send_newkeys(ssh);
198: out:
199: explicit_bzero(hash, sizeof(hash));
200: DH_free(kex->dh);
201: kex->dh = NULL;
202: if (dh_server_pub)
203: BN_clear_free(dh_server_pub);
204: if (kbuf) {
205: explicit_bzero(kbuf, klen);
206: free(kbuf);
207: }
208: if (shared_secret)
209: BN_clear_free(shared_secret);
210: sshkey_free(server_host_key);
211: free(server_host_key_blob);
212: free(signature);
213: return r;
1.1 markus 214: }
![[BACK]](/icons/back.gif){kind=icon}
Return to kexdhc.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh