jsing@openbsd.org | 7cd3163 | 2018-02-07 02:06:50 +0000 | [diff] [blame] | 1 | /* $OpenBSD: kexdhc.c,v 1.22 2018/02/07 02:06:51 jsing 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" |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 44 | #include "kex.h" |
| 45 | #include "log.h" |
| 46 | #include "packet.h" |
| 47 | #include "dh.h" |
| 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 */ |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 64 | switch (kex->kex_type) { |
| 65 | case KEX_DH_GRP1_SHA1: |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 66 | kex->dh = dh_new_group1(); |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 67 | break; |
| 68 | case KEX_DH_GRP14_SHA1: |
djm@openbsd.org | 0e8eeec | 2016-05-02 10:26:04 +0000 | [diff] [blame] | 69 | case KEX_DH_GRP14_SHA256: |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 70 | kex->dh = dh_new_group14(); |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 71 | break; |
djm@openbsd.org | 0e8eeec | 2016-05-02 10:26:04 +0000 | [diff] [blame] | 72 | case KEX_DH_GRP16_SHA512: |
| 73 | kex->dh = dh_new_group16(); |
| 74 | break; |
| 75 | case KEX_DH_GRP18_SHA512: |
| 76 | kex->dh = dh_new_group18(); |
| 77 | break; |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 78 | default: |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 79 | r = SSH_ERR_INVALID_ARGUMENT; |
| 80 | goto out; |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 81 | } |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 82 | if (kex->dh == NULL) { |
| 83 | r = SSH_ERR_ALLOC_FAIL; |
| 84 | goto out; |
| 85 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 86 | debug("sending SSH2_MSG_KEXDH_INIT"); |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 87 | if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0) |
| 88 | goto out; |
| 89 | DH_get0_key(kex->dh, &pub_key, NULL); |
| 90 | if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_INIT)) != 0 || |
| 91 | (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 || |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 92 | (r = sshpkt_send(ssh)) != 0) |
| 93 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 94 | #ifdef DEBUG_KEXDH |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 95 | DHparams_print_fp(stderr, kex->dh); |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 96 | fprintf(stderr, "pub= "); |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 97 | BN_print_fp(stderr, pub_key); |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 98 | fprintf(stderr, "\n"); |
| 99 | #endif |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 100 | debug("expecting SSH2_MSG_KEXDH_REPLY"); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 101 | ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_REPLY, &input_kex_dh); |
| 102 | r = 0; |
| 103 | out: |
| 104 | return r; |
| 105 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 106 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 107 | static int |
markus@openbsd.org | 2ae666a | 2017-05-30 14:23:52 +0000 | [diff] [blame] | 108 | 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] | 109 | { |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 110 | struct kex *kex = ssh->kex; |
| 111 | BIGNUM *dh_server_pub = NULL, *shared_secret = NULL; |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 112 | const BIGNUM *pub_key; |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 113 | struct sshkey *server_host_key = NULL; |
| 114 | u_char *kbuf = NULL, *server_host_key_blob = NULL, *signature = NULL; |
| 115 | u_char hash[SSH_DIGEST_MAX_LENGTH]; |
| 116 | size_t klen = 0, slen, sbloblen, hashlen; |
| 117 | int kout, r; |
| 118 | |
| 119 | if (kex->verify_host_key == NULL) { |
| 120 | r = SSH_ERR_INVALID_ARGUMENT; |
| 121 | goto out; |
| 122 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 123 | /* key, cert */ |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 124 | if ((r = sshpkt_get_string(ssh, &server_host_key_blob, |
| 125 | &sbloblen)) != 0 || |
| 126 | (r = sshkey_from_blob(server_host_key_blob, sbloblen, |
| 127 | &server_host_key)) != 0) |
| 128 | goto out; |
djm@openbsd.org | 5104db7 | 2015-01-26 06:10:03 +0000 | [diff] [blame] | 129 | if (server_host_key->type != kex->hostkey_type || |
| 130 | (kex->hostkey_type == KEY_ECDSA && |
| 131 | server_host_key->ecdsa_nid != kex->hostkey_nid)) { |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 132 | r = SSH_ERR_KEY_TYPE_MISMATCH; |
| 133 | goto out; |
| 134 | } |
| 135 | if (kex->verify_host_key(server_host_key, ssh) == -1) { |
| 136 | r = SSH_ERR_SIGNATURE_INVALID; |
| 137 | goto out; |
| 138 | } |
Damien Miller | ad6b14d | 2006-06-13 13:00:41 +1000 | [diff] [blame] | 139 | /* DH parameter f, server public DH key */ |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 140 | if ((dh_server_pub = BN_new()) == NULL) { |
| 141 | r = SSH_ERR_ALLOC_FAIL; |
| 142 | goto out; |
| 143 | } |
| 144 | /* signed H */ |
| 145 | if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 || |
| 146 | (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 || |
| 147 | (r = sshpkt_get_end(ssh)) != 0) |
| 148 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 149 | #ifdef DEBUG_KEXDH |
| 150 | fprintf(stderr, "dh_server_pub= "); |
| 151 | BN_print_fp(stderr, dh_server_pub); |
| 152 | fprintf(stderr, "\n"); |
| 153 | debug("bits %d", BN_num_bits(dh_server_pub)); |
| 154 | #endif |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 155 | if (!dh_pub_is_valid(kex->dh, dh_server_pub)) { |
| 156 | sshpkt_disconnect(ssh, "bad server public DH value"); |
| 157 | r = SSH_ERR_MESSAGE_INCOMPLETE; |
| 158 | goto out; |
| 159 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 160 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 161 | klen = DH_size(kex->dh); |
| 162 | if ((kbuf = malloc(klen)) == NULL || |
| 163 | (shared_secret = BN_new()) == NULL) { |
| 164 | r = SSH_ERR_ALLOC_FAIL; |
| 165 | goto out; |
| 166 | } |
| 167 | if ((kout = DH_compute_key(kbuf, dh_server_pub, kex->dh)) < 0 || |
| 168 | BN_bin2bn(kbuf, kout, shared_secret) == NULL) { |
| 169 | r = SSH_ERR_LIBCRYPTO_ERROR; |
| 170 | goto out; |
| 171 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 172 | #ifdef DEBUG_KEXDH |
| 173 | dump_digest("shared secret", kbuf, kout); |
| 174 | #endif |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 175 | |
| 176 | /* calc and verify H */ |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 177 | DH_get0_key(kex->dh, &pub_key, NULL); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 178 | hashlen = sizeof(hash); |
| 179 | if ((r = kex_dh_hash( |
djm@openbsd.org | 0e8eeec | 2016-05-02 10:26:04 +0000 | [diff] [blame] | 180 | kex->hash_alg, |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 181 | kex->client_version_string, |
| 182 | kex->server_version_string, |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 183 | sshbuf_ptr(kex->my), sshbuf_len(kex->my), |
| 184 | sshbuf_ptr(kex->peer), sshbuf_len(kex->peer), |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 185 | server_host_key_blob, sbloblen, |
djm@openbsd.org | 482d23b | 2018-09-13 02:08:33 +0000 | [diff] [blame] | 186 | pub_key, |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 187 | dh_server_pub, |
Damien Miller | 19bb3a5 | 2005-11-05 15:19:35 +1100 | [diff] [blame] | 188 | shared_secret, |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 189 | hash, &hashlen)) != 0) |
| 190 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 191 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 192 | if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen, |
djm@openbsd.org | 04c7e28 | 2017-12-18 02:25:15 +0000 | [diff] [blame] | 193 | kex->hostkey_alg, ssh->compat)) != 0) |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 194 | goto out; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 195 | |
| 196 | /* save session id */ |
| 197 | if (kex->session_id == NULL) { |
Damien Miller | 19bb3a5 | 2005-11-05 15:19:35 +1100 | [diff] [blame] | 198 | kex->session_id_len = hashlen; |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 199 | kex->session_id = malloc(kex->session_id_len); |
| 200 | if (kex->session_id == NULL) { |
| 201 | r = SSH_ERR_ALLOC_FAIL; |
| 202 | goto out; |
| 203 | } |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 204 | memcpy(kex->session_id, hash, kex->session_id_len); |
| 205 | } |
| 206 | |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 207 | if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0) |
| 208 | r = kex_send_newkeys(ssh); |
| 209 | out: |
| 210 | explicit_bzero(hash, sizeof(hash)); |
| 211 | DH_free(kex->dh); |
| 212 | kex->dh = NULL; |
jsing@openbsd.org | 7cd3163 | 2018-02-07 02:06:50 +0000 | [diff] [blame] | 213 | BN_clear_free(dh_server_pub); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 214 | if (kbuf) { |
| 215 | explicit_bzero(kbuf, klen); |
| 216 | free(kbuf); |
| 217 | } |
jsing@openbsd.org | 7cd3163 | 2018-02-07 02:06:50 +0000 | [diff] [blame] | 218 | BN_clear_free(shared_secret); |
markus@openbsd.org | 57d10cb | 2015-01-19 20:16:15 +0000 | [diff] [blame] | 219 | sshkey_free(server_host_key); |
| 220 | free(server_host_key_blob); |
| 221 | free(signature); |
| 222 | return r; |
Damien Miller | 8e7fb33 | 2003-02-24 12:03:03 +1100 | [diff] [blame] | 223 | } |
Damien Miller | 72ef7c1 | 2015-01-15 02:21:31 +1100 | [diff] [blame] | 224 | #endif /* WITH_OPENSSL */ |