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 along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include <openssl/evp.h>
24 #include <openssl/err.h>
25 #include <openssl/rand.h>
28 #include "connection.h"
37 bool mykeyused = false;
39 bool send_key_changed() {
40 /* Only send this message if some other daemon requested our key previously.
41 This reduces unnecessary key_changed broadcasts.
47 return send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name);
50 bool key_changed_h(connection_t *c) {
51 char name[MAX_STRING_SIZE];
54 if(sscanf(c->buffer, "%*d %*x " MAX_STRING, name) != 1) {
55 logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
56 c->name, c->hostname);
61 logger(LOG_ERR, "Got bad %s from %s (%s): %s", "KEY_CHANGED", c->name, c->hostname, "invalid name");
65 if(seen_request(c->buffer))
68 n = lookup_node(name);
71 logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
72 "KEY_CHANGED", c->name, c->hostname, name);
76 n->status.validkey = false;
87 bool send_req_key(node_t *to) {
88 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
91 bool req_key_h(connection_t *c) {
92 char from_name[MAX_STRING_SIZE];
93 char to_name[MAX_STRING_SIZE];
96 if(sscanf(c->buffer, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
97 logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
102 if(!check_id(from_name) || !check_id(to_name)) {
103 logger(LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
107 from = lookup_node(from_name);
110 logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
111 "REQ_KEY", c->name, c->hostname, from_name);
115 to = lookup_node(to_name);
118 logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
119 "REQ_KEY", c->name, c->hostname, to_name);
123 /* Check if this key request is for us */
125 if(to == myself) { /* Yes, send our own key back */
131 if(!to->status.reachable) {
132 logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
133 "REQ_KEY", c->name, c->hostname, to_name);
137 send_request(to->nexthop->connection, "%s", c->buffer);
143 bool send_ans_key(node_t *to) {
146 // Set key parameters
147 to->incipher = myself->incipher;
148 to->inkeylength = myself->inkeylength;
149 to->indigest = myself->indigest;
150 to->inmaclength = myself->inmaclength;
151 to->incompression = myself->incompression;
153 // Allocate memory for key
154 to->inkey = xrealloc(to->inkey, to->inkeylength);
157 RAND_pseudo_bytes((unsigned char *)to->inkey, to->inkeylength);
159 EVP_DecryptInit_ex(&to->inctx, to->incipher, NULL, (unsigned char *)to->inkey, (unsigned char *)to->inkey + to->incipher->key_len);
161 // Reset sequence number and late packet window
163 to->received_seqno = 0;
164 memset(to->late, 0, sizeof(to->late));
166 // Convert to hexadecimal and send
167 key = alloca(2 * to->inkeylength + 1);
168 bin2hex(to->inkey, key, to->inkeylength);
169 key[to->inkeylength * 2] = '\0';
171 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
172 myself->name, to->name, key,
173 to->incipher ? to->incipher->nid : 0,
174 to->indigest ? to->indigest->type : 0, to->inmaclength,
178 bool ans_key_h(connection_t *c) {
179 char from_name[MAX_STRING_SIZE];
180 char to_name[MAX_STRING_SIZE];
181 char key[MAX_STRING_SIZE];
182 char address[MAX_STRING_SIZE] = "";
183 char port[MAX_STRING_SIZE] = "";
184 int cipher, digest, maclength, compression;
187 if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
188 from_name, to_name, key, &cipher, &digest, &maclength,
189 &compression, address, port) < 7) {
190 logger(LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
195 if(!check_id(from_name) || !check_id(to_name)) {
196 logger(LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
200 from = lookup_node(from_name);
203 logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
204 "ANS_KEY", c->name, c->hostname, from_name);
208 to = lookup_node(to_name);
211 logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
212 "ANS_KEY", c->name, c->hostname, to_name);
216 /* Forward it if necessary */
222 if(!to->status.reachable) {
223 logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
224 "ANS_KEY", c->name, c->hostname, to_name);
229 char *address, *port;
230 ifdebug(PROTOCOL) logger(LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
231 sockaddr2str(&from->address, &address, &port);
232 send_request(to->nexthop->connection, "%s %s %s", c->buffer, address, port);
238 return send_request(to->nexthop->connection, "%s", c->buffer);
241 /* Update our copy of the origin's packet key */
242 from->outkey = xrealloc(from->outkey, strlen(key) / 2);
244 from->outkey = xstrdup(key);
245 from->outkeylength = strlen(key) / 2;
246 hex2bin(key, from->outkey, from->outkeylength);
248 /* Check and lookup cipher and digest algorithms */
251 from->outcipher = EVP_get_cipherbynid(cipher);
253 if(!from->outcipher) {
254 logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name,
259 if(from->outkeylength != from->outcipher->key_len + from->outcipher->iv_len) {
260 logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name,
265 from->outcipher = NULL;
268 from->outmaclength = maclength;
271 from->outdigest = EVP_get_digestbynid(digest);
273 if(!from->outdigest) {
274 logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name,
279 if(from->outmaclength > from->outdigest->md_size || from->outmaclength < 0) {
280 logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!",
281 from->name, from->hostname);
285 from->outdigest = NULL;
288 if(compression < 0 || compression > 11) {
289 logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
293 from->outcompression = compression;
296 if(!EVP_EncryptInit_ex(&from->outctx, from->outcipher, NULL, (unsigned char *)from->outkey, (unsigned char *)from->outkey + from->outcipher->key_len)) {
297 logger(LOG_ERR, "Error during initialisation of key from %s (%s): %s",
298 from->name, from->hostname, ERR_error_string(ERR_get_error(), NULL));
302 from->status.validkey = true;
303 from->sent_seqno = 0;
305 if(*address && *port) {
306 ifdebug(PROTOCOL) logger(LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
307 sockaddr_t sa = str2sockaddr(address, port);
308 update_node_udp(from, &sa);
311 if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuprobes)
312 send_mtu_probe(from);