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 | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 26 | RCSID("$OpenBSD: kex.c,v 1.27 2001/04/03 23:32:11 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 | 20d7c7b | 2001-04-04 01:56:17 +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 |
| 115 | kex_send_newkeys(void) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 116 | { |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 117 | packet_start(SSH2_MSG_NEWKEYS); |
| 118 | packet_send(); |
| 119 | /* packet_write_wait(); */ |
| 120 | debug("SSH2_MSG_NEWKEYS sent"); |
| 121 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 122 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 123 | void |
| 124 | kex_input_newkeys(int type, int plen, void *ctxt) |
| 125 | { |
| 126 | Kex *kex = ctxt; |
| 127 | int i; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 128 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 129 | debug("SSH2_MSG_NEWKEYS received"); |
| 130 | kex->newkeys = 1; |
| 131 | for (i = 30; i <= 49; i++) |
| 132 | dispatch_set(i, &kex_protocol_error); |
| 133 | buffer_clear(&kex->peer); |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 134 | /* buffer_clear(&kex->my); */ |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 135 | kex->flags &= ~KEX_INIT_SENT; |
| 136 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 137 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 138 | void |
| 139 | kex_send_kexinit(Kex *kex) |
| 140 | { |
| 141 | packet_start(SSH2_MSG_KEXINIT); |
| 142 | packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); |
| 143 | packet_send(); |
| 144 | debug("SSH2_MSG_KEXINIT sent"); |
| 145 | kex->flags |= KEX_INIT_SENT; |
| 146 | } |
| 147 | |
| 148 | void |
| 149 | kex_input_kexinit(int type, int plen, void *ctxt) |
| 150 | { |
| 151 | char *ptr; |
| 152 | int dlen; |
| 153 | Kex *kex = (Kex *)ctxt; |
| 154 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 155 | debug("SSH2_MSG_KEXINIT received"); |
| 156 | |
| 157 | ptr = packet_get_raw(&dlen); |
| 158 | buffer_append(&kex->peer, ptr, dlen); |
| 159 | |
| 160 | kex_kexinit_finish(kex); |
| 161 | } |
| 162 | |
| 163 | Kex * |
| 164 | kex_start(char *proposal[PROPOSAL_MAX]) |
| 165 | { |
| 166 | Kex *kex; |
| 167 | int i; |
| 168 | |
| 169 | kex = xmalloc(sizeof(*kex)); |
| 170 | memset(kex, 0, sizeof(*kex)); |
| 171 | buffer_init(&kex->peer); |
| 172 | buffer_init(&kex->my); |
| 173 | kex_prop2buf(&kex->my, proposal); |
| 174 | kex->newkeys = 0; |
| 175 | |
| 176 | kex_send_kexinit(kex); /* we start */ |
| 177 | /* Numbers 30-49 are used for kex packets */ |
| 178 | for (i = 30; i <= 49; i++) |
| 179 | dispatch_set(i, kex_protocol_error); |
| 180 | |
| 181 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
| 182 | dispatch_set(SSH2_MSG_NEWKEYS, &kex_input_newkeys); |
| 183 | return kex; |
| 184 | } |
| 185 | |
| 186 | void |
| 187 | kex_kexinit_finish(Kex *kex) |
| 188 | { |
| 189 | if (!(kex->flags & KEX_INIT_SENT)) |
| 190 | kex_send_kexinit(kex); |
| 191 | |
| 192 | kex_choose_conf(kex); |
| 193 | |
| 194 | switch(kex->kex_type) { |
| 195 | case DH_GRP1_SHA1: |
| 196 | kexdh(kex); |
| 197 | break; |
| 198 | case DH_GEX_SHA1: |
| 199 | kexgex(kex); |
| 200 | break; |
| 201 | default: |
| 202 | fatal("Unsupported key exchange %d", kex->kex_type); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 203 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 204 | } |
| 205 | |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 206 | void |
| 207 | choose_enc(Enc *enc, char *client, char *server) |
| 208 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 209 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 210 | if (name == NULL) |
| 211 | fatal("no matching cipher found: client %s server %s", client, server); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 212 | enc->cipher = cipher_by_name(name); |
| 213 | if (enc->cipher == NULL) |
| 214 | fatal("matching cipher is not supported: %s", name); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 215 | enc->name = name; |
| 216 | enc->enabled = 0; |
| 217 | enc->iv = NULL; |
| 218 | enc->key = NULL; |
| 219 | } |
| 220 | void |
| 221 | choose_mac(Mac *mac, char *client, char *server) |
| 222 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 223 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 224 | if (name == NULL) |
| 225 | fatal("no matching mac found: client %s server %s", client, server); |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 226 | if (mac_init(mac, name) < 0) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 227 | fatal("unsupported mac %s", name); |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 228 | /* truncate the key */ |
| 229 | if (datafellows & SSH_BUG_HMAC) |
| 230 | mac->key_len = 16; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 231 | mac->name = name; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 232 | mac->key = NULL; |
| 233 | mac->enabled = 0; |
| 234 | } |
| 235 | void |
| 236 | choose_comp(Comp *comp, char *client, char *server) |
| 237 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 238 | char *name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 239 | if (name == NULL) |
| 240 | fatal("no matching comp found: client %s server %s", client, server); |
| 241 | if (strcmp(name, "zlib") == 0) { |
| 242 | comp->type = 1; |
| 243 | } else if (strcmp(name, "none") == 0) { |
| 244 | comp->type = 0; |
| 245 | } else { |
| 246 | fatal("unsupported comp %s", name); |
| 247 | } |
| 248 | comp->name = name; |
| 249 | } |
| 250 | void |
| 251 | choose_kex(Kex *k, char *client, char *server) |
| 252 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 253 | k->name = match_list(client, server, NULL); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 254 | if (k->name == NULL) |
| 255 | fatal("no kex alg"); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 256 | if (strcmp(k->name, KEX_DH1) == 0) { |
| 257 | k->kex_type = DH_GRP1_SHA1; |
| 258 | } else if (strcmp(k->name, KEX_DHGEX) == 0) { |
| 259 | k->kex_type = DH_GEX_SHA1; |
| 260 | } else |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 261 | fatal("bad kex alg %s", k->name); |
| 262 | } |
| 263 | void |
| 264 | choose_hostkeyalg(Kex *k, char *client, char *server) |
| 265 | { |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 266 | char *hostkeyalg = match_list(client, server, NULL); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 267 | if (hostkeyalg == NULL) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 268 | fatal("no hostkey alg"); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 269 | k->hostkey_type = key_type_from_name(hostkeyalg); |
| 270 | if (k->hostkey_type == KEY_UNSPEC) |
| 271 | fatal("bad hostkey alg '%s'", hostkeyalg); |
Ben Lindstrom | 48bd7c1 | 2001-01-09 00:35:42 +0000 | [diff] [blame] | 272 | xfree(hostkeyalg); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 273 | } |
| 274 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 275 | void |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 276 | kex_choose_conf(Kex *kex) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 277 | { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 278 | Newkeys *newkeys; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 279 | char **my, **peer; |
| 280 | char **cprop, **sprop; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 281 | int nenc, nmac, ncomp; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 282 | int mode; |
| 283 | int ctos; /* direction: if true client-to-server */ |
| 284 | int need; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 285 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 286 | my = kex_buf2prop(&kex->my); |
| 287 | peer = kex_buf2prop(&kex->peer); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 288 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 289 | if (kex->server) { |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 290 | cprop=peer; |
| 291 | sprop=my; |
| 292 | } else { |
| 293 | cprop=my; |
| 294 | sprop=peer; |
| 295 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 296 | |
| 297 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 298 | newkeys = xmalloc(sizeof(*newkeys)); |
| 299 | memset(newkeys, 0, sizeof(*newkeys)); |
| 300 | kex->keys[mode] = newkeys; |
| 301 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 302 | nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; |
| 303 | nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; |
| 304 | ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 305 | choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); |
| 306 | choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); |
| 307 | choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 308 | debug("kex: %s %s %s %s", |
| 309 | ctos ? "client->server" : "server->client", |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 310 | newkeys->enc.name, |
| 311 | newkeys->mac.name, |
| 312 | newkeys->comp.name); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 313 | } |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 314 | choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
| 315 | choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 316 | sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 317 | need = 0; |
| 318 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 319 | newkeys = kex->keys[mode]; |
| 320 | if (need < newkeys->enc.cipher->key_len) |
| 321 | need = newkeys->enc.cipher->key_len; |
| 322 | if (need < newkeys->enc.cipher->block_size) |
| 323 | need = newkeys->enc.cipher->block_size; |
| 324 | if (need < newkeys->mac.key_len) |
| 325 | need = newkeys->mac.key_len; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 326 | } |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 327 | /* XXX need runden? */ |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 328 | kex->we_need = need; |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 329 | |
| 330 | kex_prop_free(my); |
| 331 | kex_prop_free(peer); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 332 | } |
| 333 | |
| 334 | u_char * |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 335 | 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] | 336 | { |
| 337 | Buffer b; |
| 338 | EVP_MD *evp_md = EVP_sha1(); |
| 339 | EVP_MD_CTX md; |
| 340 | char c = id; |
| 341 | int have; |
| 342 | int mdsz = evp_md->md_size; |
| 343 | u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz); |
| 344 | |
| 345 | buffer_init(&b); |
| 346 | buffer_put_bignum2(&b, shared_secret); |
| 347 | |
| 348 | EVP_DigestInit(&md, evp_md); |
| 349 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); /* shared_secret K */ |
| 350 | EVP_DigestUpdate(&md, hash, mdsz); /* transport-06 */ |
| 351 | EVP_DigestUpdate(&md, &c, 1); /* key id */ |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 352 | EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 353 | EVP_DigestFinal(&md, digest, NULL); |
| 354 | |
| 355 | /* expand */ |
| 356 | for (have = mdsz; need > have; have += mdsz) { |
| 357 | EVP_DigestInit(&md, evp_md); |
| 358 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
| 359 | EVP_DigestUpdate(&md, hash, mdsz); |
| 360 | EVP_DigestUpdate(&md, digest, have); |
| 361 | EVP_DigestFinal(&md, digest + have, NULL); |
| 362 | } |
| 363 | buffer_free(&b); |
| 364 | #ifdef DEBUG_KEX |
| 365 | fprintf(stderr, "key '%c'== ", c); |
| 366 | dump_digest("key", digest, need); |
| 367 | #endif |
| 368 | return digest; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 369 | } |
| 370 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 371 | Newkeys *x_newkeys[MODE_MAX]; |
| 372 | |
Ben Lindstrom | b9be60a | 2001-03-11 01:49:19 +0000 | [diff] [blame] | 373 | #define NKEYS 6 |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 374 | void |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 375 | kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 376 | { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 377 | Newkeys *newkeys; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 378 | u_char *keys[NKEYS]; |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 379 | int i, mode, ctos; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 380 | |
| 381 | for (i = 0; i < NKEYS; i++) |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 382 | 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] | 383 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 384 | debug("kex_derive_keys"); |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 385 | for (mode = 0; mode < MODE_MAX; mode++) { |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 386 | newkeys = kex->keys[mode]; |
| 387 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
| 388 | newkeys->enc.iv = keys[ctos ? 0 : 1]; |
| 389 | newkeys->enc.key = keys[ctos ? 2 : 3]; |
| 390 | newkeys->mac.key = keys[ctos ? 4 : 5]; |
| 391 | x_newkeys[mode] = newkeys; |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 392 | } |
Damien Miller | a664e87 | 2000-04-16 11:52:47 +1000 | [diff] [blame] | 393 | } |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 394 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame^] | 395 | Newkeys * |
| 396 | kex_get_newkeys(int mode) |
| 397 | { |
| 398 | return x_newkeys[mode]; |
| 399 | } |
| 400 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 401 | #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) |
| 402 | void |
| 403 | dump_digest(char *msg, u_char *digest, int len) |
| 404 | { |
| 405 | int i; |
| 406 | |
| 407 | fprintf(stderr, "%s\n", msg); |
| 408 | for (i = 0; i< len; i++){ |
| 409 | fprintf(stderr, "%02x", digest[i]); |
| 410 | if (i%32 == 31) |
| 411 | fprintf(stderr, "\n"); |
| 412 | else if (i%8 == 7) |
| 413 | fprintf(stderr, " "); |
| 414 | } |
| 415 | fprintf(stderr, "\n"); |
| 416 | } |
| 417 | #endif |