2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2009 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <openssl/evp.h>
26 #include <openssl/err.h>
27 #include <openssl/rand.h>
30 #include "connection.h"
39 bool mykeyused = false;
41 bool send_key_changed()
45 /* Only send this message if some other daemon requested our key previously.
46 This reduces unnecessary key_changed broadcasts.
52 return send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name);
55 bool key_changed_h(connection_t *c)
57 char name[MAX_STRING_SIZE];
62 if(sscanf(c->buffer, "%*d %*x " MAX_STRING, name) != 1) {
63 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "KEY_CHANGED",
64 c->name, c->hostname);
68 if(seen_request(c->buffer))
71 n = lookup_node(name);
74 logger(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist"),
75 "KEY_CHANGED", c->name, c->hostname, name);
79 n->status.validkey = false;
80 n->status.waitingforkey = false;
90 bool send_req_key(node_t *to)
94 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
97 bool req_key_h(connection_t *c)
99 char from_name[MAX_STRING_SIZE];
100 char to_name[MAX_STRING_SIZE];
105 if(sscanf(c->buffer, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
106 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "REQ_KEY", c->name,
111 from = lookup_node(from_name);
114 logger(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist in our connection list"),
115 "REQ_KEY", c->name, c->hostname, from_name);
119 to = lookup_node(to_name);
122 logger(LOG_ERR, _("Got %s from %s (%s) destination %s which does not exist in our connection list"),
123 "REQ_KEY", c->name, c->hostname, to_name);
127 /* Check if this key request is for us */
129 if(to == myself) { /* Yes, send our own key back */
135 if(!to->status.reachable) {
136 logger(LOG_WARNING, _("Got %s from %s (%s) destination %s which is not reachable"),
137 "REQ_KEY", c->name, c->hostname, to_name);
141 send_request(to->nexthop->connection, "%s", c->buffer);
147 bool send_ans_key(node_t *to)
153 // Set key parameters
154 to->incipher = myself->incipher;
155 to->inkeylength = myself->inkeylength;
156 to->indigest = myself->indigest;
157 to->inmaclength = myself->inmaclength;
158 to->incompression = myself->incompression;
160 // Allocate memory for key
161 to->inkey = xrealloc(to->inkey, to->inkeylength);
164 RAND_pseudo_bytes((unsigned char *)to->inkey, to->inkeylength);
166 EVP_DecryptInit_ex(&to->inctx, to->incipher, NULL, (unsigned char *)to->inkey, (unsigned char *)to->inkey + to->incipher->key_len);
168 // Reset sequence number and late packet window
170 to->received_seqno = 0;
171 memset(to->late, 0, sizeof(to->late));
173 // Convert to hexadecimal and send
174 key = alloca(2 * to->inkeylength + 1);
175 bin2hex(to->inkey, key, to->inkeylength);
176 key[to->inkeylength * 2] = '\0';
178 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
179 myself->name, to->name, key,
180 to->incipher ? to->incipher->nid : 0,
181 to->indigest ? to->indigest->type : 0, to->inmaclength,
185 bool ans_key_h(connection_t *c)
187 char from_name[MAX_STRING_SIZE];
188 char to_name[MAX_STRING_SIZE];
189 char key[MAX_STRING_SIZE];
190 int cipher, digest, maclength, compression;
195 if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d",
196 from_name, to_name, key, &cipher, &digest, &maclength,
197 &compression) != 7) {
198 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "ANS_KEY", c->name,
203 from = lookup_node(from_name);
206 logger(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist in our connection list"),
207 "ANS_KEY", c->name, c->hostname, from_name);
211 to = lookup_node(to_name);
214 logger(LOG_ERR, _("Got %s from %s (%s) destination %s which does not exist in our connection list"),
215 "ANS_KEY", c->name, c->hostname, to_name);
219 /* Forward it if necessary */
225 if(!to->status.reachable) {
226 logger(LOG_WARNING, _("Got %s from %s (%s) destination %s which is not reachable"),
227 "ANS_KEY", c->name, c->hostname, to_name);
231 return send_request(to->nexthop->connection, "%s", c->buffer);
234 /* Update our copy of the origin's packet key */
235 from->outkey = xrealloc(from->outkey, strlen(key) / 2);
237 from->outkey = xstrdup(key);
238 from->outkeylength = strlen(key) / 2;
239 hex2bin(key, from->outkey, from->outkeylength);
241 from->status.waitingforkey = false;
242 /* Check and lookup cipher and digest algorithms */
245 from->outcipher = EVP_get_cipherbynid(cipher);
247 if(!from->outcipher) {
248 logger(LOG_ERR, _("Node %s (%s) uses unknown cipher!"), from->name,
253 if(from->outkeylength != from->outcipher->key_len + from->outcipher->iv_len) {
254 logger(LOG_ERR, _("Node %s (%s) uses wrong keylength!"), from->name,
259 from->outcipher = NULL;
262 from->outmaclength = maclength;
265 from->outdigest = EVP_get_digestbynid(digest);
267 if(!from->outdigest) {
268 logger(LOG_ERR, _("Node %s (%s) uses unknown digest!"), from->name,
273 if(from->outmaclength > from->outdigest->md_size || from->outmaclength < 0) {
274 logger(LOG_ERR, _("Node %s (%s) uses bogus MAC length!"),
275 from->name, from->hostname);
279 from->outdigest = NULL;
282 if(compression < 0 || compression > 11) {
283 logger(LOG_ERR, _("Node %s (%s) uses bogus compression level!"), from->name, from->hostname);
287 from->outcompression = compression;
290 if(!EVP_EncryptInit_ex(&from->outctx, from->outcipher, NULL, (unsigned char *)from->outkey, (unsigned char *)from->outkey + from->outcipher->key_len)) {
291 logger(LOG_ERR, _("Error during initialisation of key from %s (%s): %s"),
292 from->name, from->hostname, ERR_error_string(ERR_get_error(), NULL));
296 from->status.validkey = true;
297 from->sent_seqno = 0;
299 if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuprobes)
300 send_mtu_probe(from);