2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2010 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 "splay_tree.h"
25 #include "connection.h"
27 #include "control_common.h"
43 bool send_id(connection_t *c) {
44 gettimeofday(&c->start, NULL);
46 return send_request(c, "%d %s %d.%d", ID, myself->connection->name,
47 myself->connection->protocol_major, myself->connection->protocol_minor);
50 bool id_h(connection_t *c, char *request) {
51 char name[MAX_STRING_SIZE];
53 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
54 logger(LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
59 /* Check if this is a control connection */
61 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
62 c->status.control = true;
63 c->allow_request = CONTROL;
64 c->last_ping_time = time(NULL) + 3600;
65 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
68 /* Check if identity is a valid name */
71 logger(LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
72 c->hostname, "invalid name");
76 /* If this is an outgoing connection, make sure we are connected to the right host */
79 if(strcmp(c->name, name)) {
80 logger(LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
87 c->name = xstrdup(name);
90 /* Check if version matches */
92 if(c->protocol_major != myself->connection->protocol_major) {
93 logger(LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
94 c->name, c->hostname, c->protocol_major, c->protocol_minor);
100 init_configuration(&c->config_tree);
101 c->allow_request = ACK;
105 if(!c->config_tree) {
106 init_configuration(&c->config_tree);
108 if(!read_connection_config(c)) {
109 logger(LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname,
115 c->allow_request = METAKEY;
117 if(c->protocol_minor >= 2)
118 return send_metakey_ec(c);
120 return send_metakey(c);
123 bool send_metakey_ec(connection_t *c) {
124 if(!read_ecdsa_public_key(c))
127 logger(LOG_DEBUG, "Sending ECDH metakey to %s", c->name);
129 size_t siglen = ecdsa_size(&myself->connection->ecdsa);
134 // TODO: include nonce? Use relevant parts of SSH or TLS protocol
136 if(!ecdh_generate_public(&c->ecdh, key))
139 if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, sig))
142 char out[MAX_STRING_SIZE];
144 bin2hex(key, out, ECDH_SIZE);
145 bin2hex(sig, out + ECDH_SIZE * 2, siglen);
146 out[(ECDH_SIZE + siglen) * 2] = 0;
148 bool result = send_request(c, "%d %s", METAKEY, out);
151 bool send_metakey(connection_t *c) {
152 size_t len = rsa_size(&c->rsa);
155 char hexkey[2 * len + 1];
157 if(!read_rsa_public_key(c))
160 if(!cipher_open_blowfish_ofb(&c->outcipher))
163 if(!digest_open_sha1(&c->outdigest, -1))
166 /* Create a random key */
170 /* The message we send must be smaller than the modulus of the RSA key.
171 By definition, for a key of k bits, the following formula holds:
173 2^(k-1) <= modulus < 2^(k)
175 Where ^ means "to the power of", not "xor".
176 This means that to be sure, we must choose our message < 2^(k-1).
177 This can be done by setting the most significant bit to zero.
182 cipher_set_key_from_rsa(&c->outcipher, key, len, true);
184 ifdebug(SCARY_THINGS) {
185 bin2hex(key, hexkey, len);
186 hexkey[len * 2] = '\0';
187 logger(LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
190 /* Encrypt the random data
192 We do not use one of the PKCS padding schemes here.
193 This is allowed, because we encrypt a totally random string
194 with a length equal to that of the modulus of the RSA key.
197 if(!rsa_public_encrypt(&c->rsa, key, len, enckey)) {
198 logger(LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
202 /* Convert the encrypted random data to a hexadecimal formatted string */
204 bin2hex(enckey, hexkey, len);
205 hexkey[len * 2] = '\0';
207 /* Send the meta key */
209 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
210 cipher_get_nid(&c->outcipher),
211 digest_get_nid(&c->outdigest), c->outmaclength,
212 c->outcompression, hexkey);
214 c->status.encryptout = true;
218 static bool metakey_ec_h(connection_t *c, const char *request) {
219 size_t siglen = ecdsa_size(&c->ecdsa);
220 char in[MAX_STRING_SIZE];
221 char key[MAX_STRING_SIZE];
224 logger(LOG_DEBUG, "Got ECDH metakey from %s", c->name);
226 if(sscanf(request, "%*d " MAX_STRING, in) != 1) {
227 logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
231 if(strlen(in) != (ECDH_SIZE + siglen) * 2) {
232 logger(LOG_ERR, "Possible intruder %s (%s): %s %d != %d", c->name, c->hostname, "wrong keylength", strlen(in) / 2, (ECDH_SIZE + siglen));
236 hex2bin(in, key, ECDH_SIZE);
237 hex2bin(in + ECDH_SIZE * 2, sig, siglen);
239 if(!ecdsa_verify(&c->ecdsa, key, ECDH_SIZE, sig)) {
240 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "invalid ECDSA signature");
244 char shared[ECDH_SHARED_SIZE * 2 + 1];
246 if(!ecdh_compute_shared(&c->ecdh, key, shared))
249 /* Update our crypto end */
251 if(!cipher_open_by_name(&c->incipher, "aes-256-ofb"))
253 if(!digest_open_by_name(&c->indigest, "sha512", -1))
255 if(!cipher_open_by_name(&c->outcipher, "aes-256-ofb"))
257 if(!digest_open_by_name(&c->outdigest, "sha512", -1))
260 size_t mykeylen = cipher_keylength(&c->incipher);
261 size_t hiskeylen = cipher_keylength(&c->outcipher);
267 if(strcmp(myself->name, c->name) < 0) {
269 hiskey = key + mykeylen * 2;
270 xasprintf(&seed, "tinc TCP key expansion %s %s", myself->name, c->name);
272 mykey = key + hiskeylen * 2;
274 xasprintf(&seed, "tinc TCP key expansion %s %s", c->name, myself->name);
277 if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
282 bin2hex(shared, shared, ECDH_SHARED_SIZE);
283 shared[ECDH_SHARED_SIZE * 2] = 0;
284 logger(LOG_DEBUG, "Shared secret is %s", shared);
286 cipher_set_key(&c->incipher, mykey, true);
287 digest_set_key(&c->indigest, mykey + mykeylen, mykeylen);
289 cipher_set_key(&c->outcipher, hiskey, false);
290 digest_set_key(&c->outdigest, hiskey + hiskeylen, hiskeylen);
292 c->status.decryptin = true;
293 c->status.encryptout = true;
294 c->allow_request = CHALLENGE;
296 return send_challenge(c);
299 bool metakey_h(connection_t *c, char *request) {
300 if(c->protocol_minor >= 2)
301 return metakey_ec_h(c, request);
303 char hexkey[MAX_STRING_SIZE];
304 int cipher, digest, maclength, compression;
305 size_t len = rsa_size(&myself->connection->rsa);
309 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
310 logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
314 /* Check if the length of the meta key is all right */
316 if(strlen(hexkey) != len * 2) {
317 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
321 /* Convert the challenge from hexadecimal back to binary */
323 hex2bin(hexkey, enckey, len);
325 /* Decrypt the meta key */
327 if(!rsa_private_decrypt(&myself->connection->rsa, enckey, len, key)) {
328 logger(LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
332 ifdebug(SCARY_THINGS) {
333 bin2hex(key, hexkey, len);
334 hexkey[len * 2] = '\0';
335 logger(LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
338 /* Check and lookup cipher and digest algorithms */
340 if(!cipher_open_by_nid(&c->incipher, cipher) || !cipher_set_key_from_rsa(&c->incipher, key, len, false)) {
341 logger(LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
345 if(!digest_open_by_nid(&c->indigest, digest, -1)) {
346 logger(LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
350 c->status.decryptin = true;
352 c->allow_request = CHALLENGE;
354 return send_challenge(c);
357 bool send_challenge(connection_t *c) {
358 size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa);
359 char buffer[len * 2 + 1];
362 c->hischallenge = xrealloc(c->hischallenge, len);
364 /* Copy random data to the buffer */
366 randomize(c->hischallenge, len);
370 bin2hex(c->hischallenge, buffer, len);
371 buffer[len * 2] = '\0';
373 /* Send the challenge */
375 return send_request(c, "%d %s", CHALLENGE, buffer);
378 bool challenge_h(connection_t *c, char *request) {
379 char buffer[MAX_STRING_SIZE];
380 size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&myself->connection->rsa);
381 size_t digestlen = digest_length(&c->indigest);
382 char digest[digestlen];
384 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
385 logger(LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
389 /* Check if the length of the challenge is all right */
391 if(strlen(buffer) != len * 2) {
392 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
396 /* Convert the challenge from hexadecimal back to binary */
398 hex2bin(buffer, buffer, len);
400 c->allow_request = CHAL_REPLY;
402 /* Calculate the hash from the challenge we received */
404 digest_create(&c->indigest, buffer, len, digest);
406 /* Convert the hash to a hexadecimal formatted string */
408 bin2hex(digest, buffer, digestlen);
409 buffer[digestlen * 2] = '\0';
413 return send_request(c, "%d %s", CHAL_REPLY, buffer);
416 bool chal_reply_h(connection_t *c, char *request) {
417 char hishash[MAX_STRING_SIZE];
419 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
420 logger(LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
425 /* Check if the length of the hash is all right */
427 if(strlen(hishash) != digest_length(&c->outdigest) * 2) {
428 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
432 /* Convert the hash to binary format */
434 hex2bin(hishash, hishash, digest_length(&c->outdigest));
436 /* Verify the hash */
438 if(!digest_verify(&c->outdigest, c->hischallenge, c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa), hishash)) {
439 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
443 /* Identity has now been positively verified.
444 Send an acknowledgement with the rest of the information needed.
447 free(c->hischallenge);
448 c->hischallenge = NULL;
449 c->allow_request = ACK;
454 bool send_ack(connection_t *c) {
455 /* ACK message contains rest of the information the other end needs
456 to create node_t and edge_t structures. */
461 /* Estimate weight */
463 gettimeofday(&now, NULL);
464 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
466 /* Check some options */
468 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
469 c->options |= OPTION_INDIRECT;
471 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
472 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
474 if(myself->options & OPTION_PMTU_DISCOVERY)
475 c->options |= OPTION_PMTU_DISCOVERY;
477 choice = myself->options & OPTION_CLAMP_MSS;
478 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
480 c->options |= OPTION_CLAMP_MSS;
482 get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
484 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, c->options);
487 static void send_everything(connection_t *c) {
488 splay_node_t *node, *node2;
493 /* Send all known subnets and edges */
496 for(node = myself->subnet_tree->head; node; node = node->next) {
498 send_add_subnet(c, s);
504 for(node = node_tree->head; node; node = node->next) {
507 for(node2 = n->subnet_tree->head; node2; node2 = node2->next) {
509 send_add_subnet(c, s);
512 for(node2 = n->edge_tree->head; node2; node2 = node2->next) {
519 bool ack_h(connection_t *c, char *request) {
520 char hisport[MAX_STRING_SIZE];
527 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
528 logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
533 /* Check if we already have a node_t for him */
535 n = lookup_node(c->name);
539 n->name = xstrdup(c->name);
543 /* Oh dear, we already have a connection to this node. */
544 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
546 if(n->connection->outgoing) {
548 logger(LOG_WARNING, "Two outgoing connections to the same node!");
550 c->outgoing = n->connection->outgoing;
552 n->connection->outgoing = NULL;
555 terminate_connection(n->connection, false);
556 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
563 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
564 c->options &= ~OPTION_PMTU_DISCOVERY;
565 options &= ~OPTION_PMTU_DISCOVERY;
567 c->options |= options;
569 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
572 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
575 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
577 c->options |= OPTION_CLAMP_MSS;
579 c->options &= ~OPTION_CLAMP_MSS;
582 if(c->protocol_minor > 0)
583 c->node->status.ecdh = true;
585 /* Activate this connection */
587 c->allow_request = ALL;
588 c->status.active = true;
590 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection with %s (%s) activated", c->name,
593 /* Send him everything we know */
597 /* Create an edge_t for this connection */
599 c->edge = new_edge();
600 c->edge->from = myself;
602 sockaddr2str(&c->address, &hisaddress, NULL);
603 c->edge->address = str2sockaddr(hisaddress, hisport);
605 c->edge->weight = (weight + c->estimated_weight) / 2;
606 c->edge->connection = c;
607 c->edge->options = c->options;
611 /* Notify everyone of the new edge */
614 send_add_edge(c, c->edge);
616 send_add_edge(broadcast, c->edge);
618 /* Run MST and SSSP algorithms */