Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 12 | * |
| 13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 23 | */ |
| 24 | |
| 25 | #include "includes.h" |
Ben Lindstrom | 8c96392 | 2001-04-30 23:06:57 +0000 | [diff] [blame] | 26 | RCSID("$OpenBSD: kex.c,v 1.34 2001/04/30 15:50:46 markus Exp $"); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 27 | |
| 28 | #include <openssl/crypto.h> |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 29 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 30 | #include "ssh2.h" |
| 31 | #include "xmalloc.h" |
| 32 | #include "buffer.h" |
| 33 | #include "bufaux.h" |
| 34 | #include "packet.h" |
| 35 | #include "compat.h" |
| 36 | #include "cipher.h" |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 37 | #include "kex.h" |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 38 | #include "key.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 39 | #include "log.h" |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 40 | #include "mac.h" |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 41 | #include "match.h" |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 42 | #include "dispatch.h" |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 43 | |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 44 | #define KEX_COOKIE_LEN 16 |
| 45 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 46 | void kex_kexinit_finish(Kex *kex); |
| 47 | void kex_choose_conf(Kex *k); |
| 48 | |
| 49 | /* put algorithm proposal into buffer */ |
| 50 | void |
| 51 | kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 52 | { |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 53 | u_int32_t rand = 0; |
| 54 | int i; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 55 | |
| 56 | buffer_clear(b); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 57 | for (i = 0; i < KEX_COOKIE_LEN; i++) { |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 58 | if (i % 4 == 0) |
| 59 | rand = arc4random(); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 60 | buffer_put_char(b, rand & 0xff); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 61 | rand >>= 8; |
| 62 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 63 | for (i = 0; i < PROPOSAL_MAX; i++) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 64 | buffer_put_cstring(b, proposal[i]); |
| 65 | buffer_put_char(b, 0); /* first_kex_packet_follows */ |
| 66 | buffer_put_int(b, 0); /* uint32 reserved */ |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 67 | } |
| 68 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 69 | /* parse buffer and return algorithm proposal */ |
| 70 | char ** |
| 71 | kex_buf2prop(Buffer *raw) |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 72 | { |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 73 | Buffer b; |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 74 | int i; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 75 | char **proposal; |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 76 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 77 | proposal = xmalloc(PROPOSAL_MAX * sizeof(char *)); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 78 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 79 | buffer_init(&b); |
| 80 | buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 81 | /* skip cookie */ |
| 82 | for (i = 0; i < KEX_COOKIE_LEN; i++) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 83 | buffer_get_char(&b); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 84 | /* extract kex init proposal strings */ |
| 85 | for (i = 0; i < PROPOSAL_MAX; i++) { |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 86 | proposal[i] = buffer_get_string(&b,NULL); |
| 87 | debug2("kex_parse_kexinit: %s", proposal[i]); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 88 | } |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 89 | /* first kex follows / reserved */ |
| 90 | i = buffer_get_char(&b); |
| 91 | debug2("kex_parse_kexinit: first_kex_follows %d ", i); |
| 92 | i = buffer_get_int(&b); |
| 93 | debug2("kex_parse_kexinit: reserved %d ", i); |
| 94 | buffer_free(&b); |
| 95 | return proposal; |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 96 | } |
| 97 | |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 98 | void |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 99 | kex_prop_free(char **proposal) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 100 | { |
| 101 | int i; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 102 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 103 | for (i = 0; i < PROPOSAL_MAX; i++) |
| 104 | xfree(proposal[i]); |
| 105 | xfree(proposal); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 106 | } |
| 107 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 108 | void |
| 109 | kex_protocol_error(int type, int plen, void *ctxt) |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 110 | { |
Ben Lindstrom | a370005 | 2001-04-05 23:26:32 +0000 | [diff] [blame] | 111 | error("Hm, kex protocol error: type %d plen %d", type, plen); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 112 | } |
| 113 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 114 | void |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 115 | kex_clear_dispatch(void) |
| 116 | { |
| 117 | int i; |
| 118 | |
| 119 | /* Numbers 30-49 are used for kex packets */ |
| 120 | for (i = 30; i <= 49; i++) |
| 121 | dispatch_set(i, &kex_protocol_error); |
| 122 | } |
| 123 | |
| 124 | void |
Ben Lindstrom | 238abf6 | 2001-04-04 17:52:53 +0000 | [diff] [blame] | 125 | kex_finish(Kex *kex) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 126 | { |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 127 | int plen; |
| 128 | |
| 129 | kex_clear_dispatch(); |
Ben Lindstrom | 238abf6 | 2001-04-04 17:52:53 +0000 | [diff] [blame] | 130 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 131 | packet_start(SSH2_MSG_NEWKEYS); |
| 132 | packet_send(); |
| 133 | /* packet_write_wait(); */ |
| 134 | debug("SSH2_MSG_NEWKEYS sent"); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 135 | |
Ben Lindstrom | a370005 | 2001-04-05 23:26:32 +0000 | [diff] [blame] | 136 | debug("waiting for SSH2_MSG_NEWKEYS"); |
| 137 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 138 | debug("SSH2_MSG_NEWKEYS received"); |
Ben Lindstrom | 5ba23b3 | 2001-04-05 02:05:21 +0000 | [diff] [blame] | 139 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 140 | kex->done = 1; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 141 | buffer_clear(&kex->peer); |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 142 | /* buffer_clear(&kex->my); */ |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 143 | kex->flags &= ~KEX_INIT_SENT; |
Ben Lindstrom | 5ba23b3 | 2001-04-05 02:05:21 +0000 | [diff] [blame] | 144 | xfree(kex->name); |
| 145 | kex->name = NULL; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 146 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 147 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 148 | void |
| 149 | kex_send_kexinit(Kex *kex) |
| 150 | { |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 151 | if (kex == NULL) { |
| 152 | error("kex_send_kexinit: no kex, cannot rekey"); |
| 153 | return; |
| 154 | } |
Ben Lindstrom | 238abf6 | 2001-04-04 17:52:53 +0000 | [diff] [blame] | 155 | if (kex->flags & KEX_INIT_SENT) { |
| 156 | debug("KEX_INIT_SENT"); |
| 157 | return; |
| 158 | } |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 159 | kex->done = 0; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 160 | packet_start(SSH2_MSG_KEXINIT); |
| 161 | packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); |
| 162 | packet_send(); |
| 163 | debug("SSH2_MSG_KEXINIT sent"); |
| 164 | kex->flags |= KEX_INIT_SENT; |
| 165 | } |
| 166 | |
| 167 | void |
| 168 | kex_input_kexinit(int type, int plen, void *ctxt) |
| 169 | { |
| 170 | char *ptr; |
| 171 | int dlen; |
Ben Lindstrom | 8e312f3 | 2001-04-04 23:50:21 +0000 | [diff] [blame] | 172 | int i; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 173 | Kex *kex = (Kex *)ctxt; |
| 174 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 175 | debug("SSH2_MSG_KEXINIT received"); |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 176 | if (kex == NULL) |
| 177 | fatal("kex_input_kexinit: no kex, cannot rekey"); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 178 | |
| 179 | ptr = packet_get_raw(&dlen); |
| 180 | buffer_append(&kex->peer, ptr, dlen); |
| 181 | |
Ben Lindstrom | 8e312f3 | 2001-04-04 23:50:21 +0000 | [diff] [blame] | 182 | /* discard packet */ |
| 183 | for (i = 0; i < KEX_COOKIE_LEN; i++) |
| 184 | packet_get_char(); |
| 185 | for (i = 0; i < PROPOSAL_MAX; i++) |
| 186 | xfree(packet_get_string(NULL)); |
| 187 | packet_get_char(); |
| 188 | packet_get_int(); |
| 189 | packet_done(); |
| 190 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 191 | kex_kexinit_finish(kex); |
| 192 | } |
| 193 | |
| 194 | Kex * |
Ben Lindstrom | 238abf6 | 2001-04-04 17:52:53 +0000 | [diff] [blame] | 195 | kex_setup(char *proposal[PROPOSAL_MAX]) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 196 | { |
| 197 | Kex *kex; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 198 | |
| 199 | kex = xmalloc(sizeof(*kex)); |
| 200 | memset(kex, 0, sizeof(*kex)); |
| 201 | buffer_init(&kex->peer); |
| 202 | buffer_init(&kex->my); |
| 203 | kex_prop2buf(&kex->my, proposal); |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 204 | kex->done = 0; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 205 | |
| 206 | kex_send_kexinit(kex); /* we start */ |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 207 | kex_clear_dispatch(); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 208 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 209 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 210 | return kex; |
| 211 | } |
| 212 | |
| 213 | void |
| 214 | kex_kexinit_finish(Kex *kex) |
| 215 | { |
| 216 | if (!(kex->flags & KEX_INIT_SENT)) |
| 217 | kex_send_kexinit(kex); |
| 218 | |
| 219 | kex_choose_conf(kex); |
| 220 | |
| 221 | switch(kex->kex_type) { |
| 222 | case DH_GRP1_SHA1: |
| 223 | kexdh(kex); |
| 224 | break; |
| 225 | case DH_GEX_SHA1: |
| 226 | kexgex(kex); |
| 227 | break; |
| 228 | default: |
| 229 | fatal("Unsupported key exchange %d", kex->kex_type); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 230 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 231 | } |
| 232 | |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 233 | void |
| 234 | choose_enc(Enc *enc, char *client, char *server) |
| 235 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 236 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 237 | if (name == NULL) |
| 238 | fatal("no matching cipher found: client %s server %s", client, server); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 239 | enc->cipher = cipher_by_name(name); |
| 240 | if (enc->cipher == NULL) |
| 241 | fatal("matching cipher is not supported: %s", name); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 242 | enc->name = name; |
| 243 | enc->enabled = 0; |
| 244 | enc->iv = NULL; |
| 245 | enc->key = NULL; |
| 246 | } |
| 247 | void |
| 248 | choose_mac(Mac *mac, char *client, char *server) |
| 249 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 250 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 251 | if (name == NULL) |
| 252 | fatal("no matching mac found: client %s server %s", client, server); |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 253 | if (mac_init(mac, name) < 0) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 254 | fatal("unsupported mac %s", name); |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 255 | /* truncate the key */ |
| 256 | if (datafellows & SSH_BUG_HMAC) |
| 257 | mac->key_len = 16; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 258 | mac->name = name; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 259 | mac->key = NULL; |
| 260 | mac->enabled = 0; |
| 261 | } |
| 262 | void |
| 263 | choose_comp(Comp *comp, char *client, char *server) |
| 264 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 265 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 266 | if (name == NULL) |
| 267 | fatal("no matching comp found: client %s server %s", client, server); |
| 268 | if (strcmp(name, "zlib") == 0) { |
| 269 | comp->type = 1; |
| 270 | } else if (strcmp(name, "none") == 0) { |
| 271 | comp->type = 0; |
| 272 | } else { |
| 273 | fatal("unsupported comp %s", name); |
| 274 | } |
| 275 | comp->name = name; |
| 276 | } |
| 277 | void |
| 278 | choose_kex(Kex *k, char *client, char *server) |
| 279 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 280 | k->name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 281 | if (k->name == NULL) |
| 282 | fatal("no kex alg"); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 283 | if (strcmp(k->name, KEX_DH1) == 0) { |
| 284 | k->kex_type = DH_GRP1_SHA1; |
| 285 | } else if (strcmp(k->name, KEX_DHGEX) == 0) { |
| 286 | k->kex_type = DH_GEX_SHA1; |
| 287 | } else |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 288 | fatal("bad kex alg %s", k->name); |
| 289 | } |
| 290 | void |
| 291 | choose_hostkeyalg(Kex *k, char *client, char *server) |
| 292 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 293 | char *hostkeyalg = match_list(client, server, NULL); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 294 | if (hostkeyalg == NULL) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 295 | fatal("no hostkey alg"); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 296 | k->hostkey_type = key_type_from_name(hostkeyalg); |
| 297 | if (k->hostkey_type == KEY_UNSPEC) |
| 298 | fatal("bad hostkey alg '%s'", hostkeyalg); |
Ben Lindstrom | 48bd7c1 | 2001-01-09 00:35:42 +0000 | [diff] [blame] | 299 | xfree(hostkeyalg); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 300 | } |
| 301 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 302 | void |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 303 | kex_choose_conf(Kex *kex) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 304 | { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 305 | Newkeys *newkeys; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 306 | char **my, **peer; |
| 307 | char **cprop, **sprop; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 308 | int nenc, nmac, ncomp; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 309 | int mode; |
| 310 | int ctos; /* direction: if true client-to-server */ |
| 311 | int need; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 312 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 313 | my = kex_buf2prop(&kex->my); |
| 314 | peer = kex_buf2prop(&kex->peer); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 315 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 316 | if (kex->server) { |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 317 | cprop=peer; |
| 318 | sprop=my; |
| 319 | } else { |
| 320 | cprop=my; |
| 321 | sprop=peer; |
| 322 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 323 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 324 | /* Algorithm Negotiation */ |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 325 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 326 | newkeys = xmalloc(sizeof(*newkeys)); |
| 327 | memset(newkeys, 0, sizeof(*newkeys)); |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 328 | kex->newkeys[mode] = newkeys; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 329 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 330 | nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; |
| 331 | nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; |
| 332 | ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 333 | choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); |
| 334 | choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); |
| 335 | choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 336 | debug("kex: %s %s %s %s", |
| 337 | ctos ? "client->server" : "server->client", |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 338 | newkeys->enc.name, |
| 339 | newkeys->mac.name, |
| 340 | newkeys->comp.name); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 341 | } |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 342 | choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
| 343 | choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 344 | sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 345 | need = 0; |
| 346 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 347 | newkeys = kex->newkeys[mode]; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 348 | if (need < newkeys->enc.cipher->key_len) |
| 349 | need = newkeys->enc.cipher->key_len; |
| 350 | if (need < newkeys->enc.cipher->block_size) |
| 351 | need = newkeys->enc.cipher->block_size; |
| 352 | if (need < newkeys->mac.key_len) |
| 353 | need = newkeys->mac.key_len; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 354 | } |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 355 | /* XXX need runden? */ |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 356 | kex->we_need = need; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 357 | |
| 358 | kex_prop_free(my); |
| 359 | kex_prop_free(peer); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 360 | } |
| 361 | |
| 362 | u_char * |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 363 | derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 364 | { |
| 365 | Buffer b; |
| 366 | EVP_MD *evp_md = EVP_sha1(); |
| 367 | EVP_MD_CTX md; |
| 368 | char c = id; |
| 369 | int have; |
| 370 | int mdsz = evp_md->md_size; |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 371 | u_char *digest = xmalloc(roundup(need, mdsz)); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 372 | |
| 373 | buffer_init(&b); |
| 374 | buffer_put_bignum2(&b, shared_secret); |
| 375 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 376 | /* K1 = HASH(K || H || "A" || session_id) */ |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 377 | EVP_DigestInit(&md, evp_md); |
Ben Lindstrom | 8c96392 | 2001-04-30 23:06:57 +0000 | [diff] [blame] | 378 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
| 379 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 380 | EVP_DigestUpdate(&md, hash, mdsz); |
| 381 | EVP_DigestUpdate(&md, &c, 1); |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 382 | EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 383 | EVP_DigestFinal(&md, digest, NULL); |
| 384 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 385 | /* |
| 386 | * expand key: |
| 387 | * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) |
| 388 | * Key = K1 || K2 || ... || Kn |
| 389 | */ |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 390 | for (have = mdsz; need > have; have += mdsz) { |
| 391 | EVP_DigestInit(&md, evp_md); |
Ben Lindstrom | 8c96392 | 2001-04-30 23:06:57 +0000 | [diff] [blame] | 392 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
| 393 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 394 | EVP_DigestUpdate(&md, hash, mdsz); |
| 395 | EVP_DigestUpdate(&md, digest, have); |
| 396 | EVP_DigestFinal(&md, digest + have, NULL); |
| 397 | } |
| 398 | buffer_free(&b); |
| 399 | #ifdef DEBUG_KEX |
| 400 | fprintf(stderr, "key '%c'== ", c); |
| 401 | dump_digest("key", digest, need); |
| 402 | #endif |
| 403 | return digest; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 404 | } |
| 405 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 406 | Newkeys *current_keys[MODE_MAX]; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 407 | |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 408 | #define NKEYS 6 |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 409 | void |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 410 | kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 411 | { |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 412 | u_char *keys[NKEYS]; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 413 | int i, mode, ctos; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 414 | |
| 415 | for (i = 0; i < NKEYS; i++) |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 416 | keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 417 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 418 | debug("kex_derive_keys"); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 419 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 420 | current_keys[mode] = kex->newkeys[mode]; |
| 421 | kex->newkeys[mode] = NULL; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 422 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 423 | current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; |
| 424 | current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; |
| 425 | current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 426 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 427 | } |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 428 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 429 | Newkeys * |
| 430 | kex_get_newkeys(int mode) |
| 431 | { |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 432 | Newkeys *ret; |
| 433 | |
| 434 | ret = current_keys[mode]; |
| 435 | current_keys[mode] = NULL; |
| 436 | return ret; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 437 | } |
| 438 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 439 | #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) |
| 440 | void |
| 441 | dump_digest(char *msg, u_char *digest, int len) |
| 442 | { |
| 443 | int i; |
| 444 | |
| 445 | fprintf(stderr, "%s\n", msg); |
| 446 | for (i = 0; i< len; i++){ |
| 447 | fprintf(stderr, "%02x", digest[i]); |
| 448 | if (i%32 == 31) |
| 449 | fprintf(stderr, "\n"); |
| 450 | else if (i%8 == 7) |
| 451 | fprintf(stderr, " "); |
| 452 | } |
| 453 | fprintf(stderr, "\n"); |
| 454 | } |
| 455 | #endif |