Annotation of src/usr.bin/ssh/kexdhs.c, Revision 1.35
1.35 ! djm 1: /* $OpenBSD: kexdhs.c,v 1.34 2019/01/21 10:03:37 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:
1.6 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"
1.33 djm 36: #include "dh.h"
1.1 markus 37: #include "kex.h"
38: #include "log.h"
39: #include "packet.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:
1.25 markus 47: static int input_kex_dh_init(int, u_int32_t, struct ssh *);
1.20 markus 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 */
1.33 djm 56: if ((r = kex_dh_keygen(kex)) != 0)
57: return r;
1.1 markus 58: debug("expecting SSH2_MSG_KEXDH_INIT");
1.20 markus 59: ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init);
1.33 djm 60: return 0;
1.20 markus 61: }
62:
63: int
1.25 markus 64: input_kex_dh_init(int type, u_int32_t seq, struct ssh *ssh)
1.20 markus 65: {
66: struct kex *kex = ssh->kex;
1.34 djm 67: BIGNUM *dh_client_pub = NULL;
1.28 djm 68: const BIGNUM *pub_key;
1.20 markus 69: struct sshkey *server_host_public, *server_host_private;
1.34 djm 70: struct sshbuf *shared_secret = NULL;
71: u_char *signature = NULL, *server_host_key_blob = NULL;
1.20 markus 72: u_char hash[SSH_DIGEST_MAX_LENGTH];
73: size_t sbloblen, slen;
1.34 djm 74: size_t hashlen;
75: int r;
1.1 markus 76:
1.35 ! djm 77: if ((r = kex_load_hostkey(ssh, &server_host_private,
! 78: &server_host_public)) != 0)
1.20 markus 79: goto out;
1.1 markus 80:
81: /* key, cert */
1.31 djm 82: if ((r = sshpkt_get_bignum2(ssh, &dh_client_pub)) != 0 ||
83: (r = sshpkt_get_end(ssh)) != 0)
1.20 markus 84: goto out;
1.34 djm 85: if ((shared_secret = sshbuf_new()) == NULL) {
1.20 markus 86: r = SSH_ERR_ALLOC_FAIL;
87: goto out;
88: }
1.34 djm 89: if ((r = kex_dh_compute_key(kex, dh_client_pub, shared_secret)) != 0)
1.20 markus 90: goto out;
91: if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
92: &sbloblen)) != 0)
93: goto out;
1.1 markus 94: /* calc H */
1.34 djm 95: DH_get0_key(kex->dh, &pub_key, NULL);
1.20 markus 96: hashlen = sizeof(hash);
97: if ((r = kex_dh_hash(
1.24 djm 98: kex->hash_alg,
1.29 djm 99: kex->client_version,
100: kex->server_version,
1.20 markus 101: sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
102: sshbuf_ptr(kex->my), sshbuf_len(kex->my),
1.1 markus 103: server_host_key_blob, sbloblen,
104: dh_client_pub,
1.28 djm 105: pub_key,
1.34 djm 106: sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
1.20 markus 107: hash, &hashlen)) != 0)
108: goto out;
1.1 markus 109:
110: /* sign H */
1.30 djm 111: if ((r = kex->sign(ssh, server_host_private, server_host_public,
112: &signature, &slen, hash, hashlen, kex->hostkey_alg)) < 0)
1.20 markus 113: goto out;
1.1 markus 114:
1.27 djm 115: /* send server hostkey, DH pubkey 'f' and signed H */
1.20 markus 116: if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 ||
117: (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
1.28 djm 118: (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 || /* f */
1.20 markus 119: (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
120: (r = sshpkt_send(ssh)) != 0)
121: goto out;
122:
1.34 djm 123: if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
1.20 markus 124: r = kex_send_newkeys(ssh);
125: out:
126: explicit_bzero(hash, sizeof(hash));
127: DH_free(kex->dh);
128: kex->dh = NULL;
1.26 jsing 129: BN_clear_free(dh_client_pub);
1.34 djm 130: sshbuf_free(shared_secret);
1.20 markus 131: free(server_host_key_blob);
1.13 djm 132: free(signature);
1.20 markus 133: return r;
1.1 markus 134: }
![[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