Annotation of src/usr.bin/ssh/kexdhs.c, Revision 1.20
1.20 ! markus 1: /* $OpenBSD: kexdhs.c,v 1.19 2015/01/19 19:52:16 markus 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:
1.6 stevesk 26:
1.7 deraadt 27: #include <sys/types.h>
1.6 stevesk 28: #include <string.h>
1.7 deraadt 29: #include <signal.h>
1.12 djm 30:
31: #include <openssl/dh.h>
1.1 markus 32:
1.20 ! markus 33: #include "sshkey.h"
1.7 deraadt 34: #include "cipher.h"
1.20 ! markus 35: #include "digest.h"
1.1 markus 36: #include "kex.h"
37: #include "log.h"
38: #include "packet.h"
39: #include "dh.h"
40: #include "ssh2.h"
41:
1.20 ! markus 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, void *);
! 48:
! 49: int
! 50: kexdh_server(struct ssh *ssh)
1.1 markus 51: {
1.20 ! markus 52: struct kex *kex = ssh->kex;
! 53: int r;
1.1 markus 54:
55: /* generate server DH public key */
1.2 djm 56: switch (kex->kex_type) {
57: case KEX_DH_GRP1_SHA1:
1.20 ! markus 58: kex->dh = dh_new_group1();
1.2 djm 59: break;
60: case KEX_DH_GRP14_SHA1:
1.20 ! markus 61: kex->dh = dh_new_group14();
1.2 djm 62: break;
63: default:
1.20 ! markus 64: r = SSH_ERR_INVALID_ARGUMENT;
! 65: goto out;
1.2 djm 66: }
1.20 ! markus 67: if (kex->dh == NULL) {
! 68: r = SSH_ERR_ALLOC_FAIL;
! 69: goto out;
! 70: }
! 71: if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
! 72: goto out;
1.1 markus 73:
74: debug("expecting SSH2_MSG_KEXDH_INIT");
1.20 ! markus 75: ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init);
! 76: r = 0;
! 77: out:
! 78: return r;
! 79: }
! 80:
! 81: int
! 82: input_kex_dh_init(int type, u_int32_t seq, void *ctxt)
! 83: {
! 84: struct ssh *ssh = ctxt;
! 85: struct kex *kex = ssh->kex;
! 86: BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
! 87: struct sshkey *server_host_public, *server_host_private;
! 88: u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
! 89: u_char hash[SSH_DIGEST_MAX_LENGTH];
! 90: size_t sbloblen, slen;
! 91: size_t klen = 0, hashlen;
! 92: int kout, r;
1.1 markus 93:
1.11 djm 94: if (kex->load_host_public_key == NULL ||
1.20 ! markus 95: kex->load_host_private_key == NULL) {
! 96: r = SSH_ERR_INVALID_ARGUMENT;
! 97: goto out;
! 98: }
! 99: if ((server_host_public = kex->load_host_public_key(kex->hostkey_type,
! 100: ssh)) == NULL ||
! 101: (server_host_private = kex->load_host_private_key(kex->hostkey_type,
! 102: ssh)) == NULL) {
! 103: r = SSH_ERR_NO_HOSTKEY_LOADED;
! 104: goto out;
! 105: }
1.1 markus 106:
107: /* key, cert */
1.20 ! markus 108: if ((dh_client_pub = BN_new()) == NULL) {
! 109: r = SSH_ERR_ALLOC_FAIL;
! 110: goto out;
! 111: }
! 112: if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
! 113: (r = sshpkt_get_end(ssh)) != 0)
! 114: goto out;
1.1 markus 115:
116: #ifdef DEBUG_KEXDH
117: fprintf(stderr, "dh_client_pub= ");
118: BN_print_fp(stderr, dh_client_pub);
119: fprintf(stderr, "\n");
120: debug("bits %d", BN_num_bits(dh_client_pub));
121: #endif
122:
123: #ifdef DEBUG_KEXDH
1.20 ! markus 124: DHparams_print_fp(stderr, kex->dh);
1.1 markus 125: fprintf(stderr, "pub= ");
1.20 ! markus 126: BN_print_fp(stderr, kex->dh->pub_key);
1.1 markus 127: fprintf(stderr, "\n");
128: #endif
1.20 ! markus 129: if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
! 130: sshpkt_disconnect(ssh, "bad client public DH value");
! 131: r = SSH_ERR_MESSAGE_INCOMPLETE;
! 132: goto out;
! 133: }
1.1 markus 134:
1.20 ! markus 135: klen = DH_size(kex->dh);
! 136: if ((kbuf = malloc(klen)) == NULL ||
! 137: (shared_secret = BN_new()) == NULL) {
! 138: r = SSH_ERR_ALLOC_FAIL;
! 139: goto out;
! 140: }
! 141: if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
! 142: BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
! 143: r = SSH_ERR_LIBCRYPTO_ERROR;
! 144: goto out;
! 145: }
1.1 markus 146: #ifdef DEBUG_KEXDH
147: dump_digest("shared secret", kbuf, kout);
148: #endif
1.20 ! markus 149: if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
! 150: &sbloblen)) != 0)
! 151: goto out;
1.1 markus 152: /* calc H */
1.20 ! markus 153: hashlen = sizeof(hash);
! 154: if ((r = kex_dh_hash(
1.1 markus 155: kex->client_version_string,
156: kex->server_version_string,
1.20 ! markus 157: sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
! 158: sshbuf_ptr(kex->my), sshbuf_len(kex->my),
1.1 markus 159: server_host_key_blob, sbloblen,
160: dh_client_pub,
1.20 ! markus 161: kex->dh->pub_key,
1.3 djm 162: shared_secret,
1.20 ! markus 163: hash, &hashlen)) != 0)
! 164: goto out;
1.1 markus 165:
166: /* save session id := H */
167: if (kex->session_id == NULL) {
1.3 djm 168: kex->session_id_len = hashlen;
1.20 ! markus 169: kex->session_id = malloc(kex->session_id_len);
! 170: if (kex->session_id == NULL) {
! 171: r = SSH_ERR_ALLOC_FAIL;
! 172: goto out;
! 173: }
1.1 markus 174: memcpy(kex->session_id, hash, kex->session_id_len);
175: }
176:
177: /* sign H */
1.20 ! markus 178: if ((r = kex->sign(server_host_private, server_host_public,
! 179: &signature, &slen, hash, hashlen, ssh->compat)) < 0)
! 180: goto out;
1.1 markus 181:
182: /* destroy_sensitive_data(); */
183:
184: /* send server hostkey, DH pubkey 'f' and singed H */
1.20 ! markus 185: if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 ||
! 186: (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
! 187: (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */
! 188: (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
! 189: (r = sshpkt_send(ssh)) != 0)
! 190: goto out;
! 191:
! 192: if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
! 193: r = kex_send_newkeys(ssh);
! 194: out:
! 195: explicit_bzero(hash, sizeof(hash));
! 196: DH_free(kex->dh);
! 197: kex->dh = NULL;
! 198: if (dh_client_pub)
! 199: BN_clear_free(dh_client_pub);
! 200: if (kbuf) {
! 201: explicit_bzero(kbuf, klen);
! 202: free(kbuf);
! 203: }
! 204: if (shared_secret)
! 205: BN_clear_free(shared_secret);
! 206: free(server_host_key_blob);
1.13 djm 207: free(signature);
1.20 ! markus 208: return r;
1.1 markus 209: }
![[BACK]](/icons/back.gif){kind=icon}
Return to kexdhs.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh