djm@openbsd.org | b1b2ff4 | 2019-01-21 10:07:22 +0000 | [diff] [blame^] | 1 | /* $OpenBSD: kexdhc.c,v 1.29 2019/01/21 10:07:22 djm Exp $ */ |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 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 | #include "includes.h" |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 27 | |
Damien Miller | 72ef7c1 | 2015-01-15 02:21:31 +1100 | [diff] [blame] | 28 | #ifdef WITH_OPENSSL |
| 29 | |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 30 | #include <sys/types.h> |
| 31 | |
Damien Miller | 4499f4c | 2010-11-20 15:15:49 +1100 | [diff] [blame] | 32 | #include <openssl/dh.h> |
| 33 | |
Damien Miller | ded319c | 2006-09-01 15:38:36 +1000 | [diff] [blame] | 34 | #include <stdarg.h> |
Damien Miller | a7a73ee | 2006-08-05 11:37:59 +1000 | [diff] [blame] | 35 | #include <stdio.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 36 | #include <string.h> |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 37 | #include <signal.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 38 | |
Damien Miller | 48f54b9 | 2018-09-13 12:13:50 +1000 | [diff] [blame] | 39 | #include "openbsd-compat/openssl-compat.h" |
| 40 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 41 | #include "sshkey.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 42 | #include "cipher.h" |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 43 | #include "digest.h" |
djm@openbsd.org | e93bd98 | 2019-01-21 10:00:23 +0000 | [diff] [blame] | 44 | #include "dh.h" |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 45 | #include "kex.h" |
| 46 | #include "log.h" |
| 47 | #include "packet.h" |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 48 | #include "ssh2.h" |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 49 | #include "dispatch.h" |
| 50 | #include "compat.h" |
| 51 | #include "ssherr.h" |
| 52 | #include "sshbuf.h" |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 53 | |
markus@openbsd.org | 2ae666a | 2017-05-30 14:23:52 +0000 | [diff] [blame] | 54 | static int input_kex_dh(int, u_int32_t, struct ssh *); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 55 | |
| 56 | int |
| 57 | kexdh_client(struct ssh *ssh) |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 58 | { |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 59 | struct kex *kex = ssh->kex; |
| 60 | int r; |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 61 | const BIGNUM *pub_key; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 62 | |
| 63 | /* generate and send 'e', client DH public key */ |
djm@openbsd.org | e93bd98 | 2019-01-21 10:00:23 +0000 | [diff] [blame] | 64 | if ((r = kex_dh_keygen(kex)) != 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 65 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 66 | debug("sending SSH2_MSG_KEXDH_INIT"); |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 67 | DH_get0_key(kex->dh, &pub_key, NULL); |
| 68 | if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_INIT)) != 0 || |
| 69 | (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 || |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 70 | (r = sshpkt_send(ssh)) != 0) |
| 71 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 72 | #ifdef DEBUG_KEXDH |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 73 | DHparams_print_fp(stderr, kex->dh); |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 74 | fprintf(stderr, "pub= "); |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 75 | BN_print_fp(stderr, pub_key); |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 76 | fprintf(stderr, "\n"); |
| 77 | #endif |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 78 | debug("expecting SSH2_MSG_KEXDH_REPLY"); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 79 | ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_REPLY, &input_kex_dh); |
| 80 | r = 0; |
| 81 | out: |
| 82 | return r; |
| 83 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 84 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 85 | static int |
markus@openbsd.org | 2ae666a | 2017-05-30 14:23:52 +0000 | [diff] [blame] | 86 | input_kex_dh(int type, u_int32_t seq, struct ssh *ssh) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 87 | { |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 88 | struct kex *kex = ssh->kex; |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 89 | BIGNUM *dh_server_pub = NULL; |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 90 | const BIGNUM *pub_key; |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 91 | struct sshkey *server_host_key = NULL; |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 92 | struct sshbuf *shared_secret = NULL; |
| 93 | u_char *server_host_key_blob = NULL, *signature = NULL; |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 94 | u_char hash[SSH_DIGEST_MAX_LENGTH]; |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 95 | size_t slen, sbloblen, hashlen; |
| 96 | int r; |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 97 | |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 98 | /* key, cert */ |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 99 | if ((r = sshpkt_get_string(ssh, &server_host_key_blob, |
| 100 | &sbloblen)) != 0 || |
| 101 | (r = sshkey_from_blob(server_host_key_blob, sbloblen, |
| 102 | &server_host_key)) != 0) |
| 103 | goto out; |
djm@openbsd.org | b1b2ff4 | 2019-01-21 10:07:22 +0000 | [diff] [blame^] | 104 | if ((r = kex_verify_host_key(ssh, server_host_key)) != 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 105 | goto out; |
djm@openbsd.org | 7be8572 | 2019-01-21 09:54:11 +0000 | [diff] [blame] | 106 | /* DH parameter f, server public DH key, signed H */ |
| 107 | if ((r = sshpkt_get_bignum2(ssh, &dh_server_pub)) != 0 || |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 108 | (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 || |
| 109 | (r = sshpkt_get_end(ssh)) != 0) |
| 110 | goto out; |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 111 | if ((shared_secret = sshbuf_new()) == NULL) { |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 112 | r = SSH_ERR_ALLOC_FAIL; |
| 113 | goto out; |
| 114 | } |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 115 | if ((r = kex_dh_compute_key(kex, dh_server_pub, shared_secret)) != 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 116 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 117 | |
| 118 | /* calc and verify H */ |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 119 | DH_get0_key(kex->dh, &pub_key, NULL); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 120 | hashlen = sizeof(hash); |
| 121 | if ((r = kex_dh_hash( |
djm@openbsd.org | 0e8eeec | 2016-05-02 10:26:04 +0000 | [diff] [blame] | 122 | kex->hash_alg, |
djm@openbsd.org | 0a843d9 | 2018-12-27 03:25:24 +0000 | [diff] [blame] | 123 | kex->client_version, |
| 124 | kex->server_version, |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 125 | sshbuf_ptr(kex->my), sshbuf_len(kex->my), |
| 126 | sshbuf_ptr(kex->peer), sshbuf_len(kex->peer), |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 127 | server_host_key_blob, sbloblen, |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 128 | pub_key, |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 129 | dh_server_pub, |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 130 | sshbuf_ptr(shared_secret), sshbuf_len(shared_secret), |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 131 | hash, &hashlen)) != 0) |
| 132 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 133 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 134 | if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen, |
djm@openbsd.org | 04c7e28 | 2017-12-18 02:25:15 +0000 | [diff] [blame] | 135 | kex->hostkey_alg, ssh->compat)) != 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 136 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 137 | |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 138 | if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 139 | r = kex_send_newkeys(ssh); |
| 140 | out: |
| 141 | explicit_bzero(hash, sizeof(hash)); |
| 142 | DH_free(kex->dh); |
| 143 | kex->dh = NULL; |
jsing@openbsd.org | 7cd3163 | 2018-02-07 02:06:50 +0000 | [diff] [blame] | 144 | BN_clear_free(dh_server_pub); |
djm@openbsd.org | dec5e9d | 2019-01-21 10:03:37 +0000 | [diff] [blame] | 145 | sshbuf_free(shared_secret); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 146 | sshkey_free(server_host_key); |
| 147 | free(server_host_key_blob); |
| 148 | free(signature); |
| 149 | return r; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 150 | } |
Damien Miller | 72ef7c1 | 2015-01-15 02:21:31 +1100 | [diff] [blame] | 151 | #endif /* WITH_OPENSSL */ |