2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2013 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.
24 #include "connection.h"
26 #include "control_common.h"
46 ecdsa_t *invitation_key = NULL;
48 static bool send_proxyrequest(connection_t *c) {
54 sockaddr2str(&c->address, &host, &port);
55 send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
61 if(c->address.sa.sa_family != AF_INET) {
62 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
65 char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
68 memcpy(s4req + 2, &c->address.in.sin_port, 2);
69 memcpy(s4req + 4, &c->address.in.sin_addr, 4);
71 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
72 s4req[sizeof s4req - 1] = 0;
74 return send_meta(c, s4req, sizeof s4req);
77 int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
80 len += 3 + strlen(proxyuser) + strlen(proxypass);
88 s5req[i++] = strlen(proxyuser);
89 memcpy(s5req + i, proxyuser, strlen(proxyuser));
90 i += strlen(proxyuser);
91 s5req[i++] = strlen(proxypass);
92 memcpy(s5req + i, proxypass, strlen(proxypass));
93 i += strlen(proxypass);
101 if(c->address.sa.sa_family == AF_INET) {
103 memcpy(s5req + i, &c->address.in.sin_addr, 4);
105 memcpy(s5req + i, &c->address.in.sin_port, 2);
108 } else if(c->address.sa.sa_family == AF_INET6) {
110 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
112 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
116 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
121 return send_meta(c, s5req, sizeof s5req);
124 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
129 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
134 bool send_id(connection_t *c) {
135 gettimeofday(&c->start, NULL);
140 if(c->outgoing && !read_ecdsa_public_key(c))
143 minor = myself->connection->protocol_minor;
146 if(proxytype && c->outgoing)
147 if(!send_proxyrequest(c))
150 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
153 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
154 if(strchr(data, '\n')) {
155 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
159 // Create a new host config file
160 char filename[PATH_MAX];
161 snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
162 if(!access(filename, F_OK)) {
163 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
167 FILE *f = fopen(filename, "w");
169 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
173 fprintf(f, "ECDSAPublicKey = %s\n", data);
176 logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
177 sptps_send_record(&c->sptps, 2, data, 0);
181 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
182 connection_t *c = handle;
187 if(type == 1 && c->status.invitation_used)
188 return finalize_invitation(c, data, len);
190 if(type != 0 || len != 18 || c->status.invitation_used)
193 // Recover the filename from the cookie and the key
194 digest_t *digest = digest_open_by_name("sha256", 18);
197 char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
198 char hashbuf[18 + strlen(fingerprint)];
200 memcpy(hashbuf, data, 18);
201 memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
202 digest_create(digest, hashbuf, sizeof hashbuf, cookie);
203 b64encode_urlsafe(cookie, cookie, 18);
204 digest_close(digest);
207 char filename[PATH_MAX], usedname[PATH_MAX];
208 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
209 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
211 // Atomically rename the invitation file
212 if(rename(filename, usedname)) {
214 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
216 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
220 // Open the renamed file
221 FILE *f = fopen(usedname, "r");
223 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
227 // Read the new node's Name from the file
229 fgets(buf, sizeof buf, f);
231 buf[strlen(buf) - 1] = 0;
233 len = strcspn(buf, " \t=");
234 char *name = buf + len;
235 name += strspn(name, " \t");
238 name += strspn(name, " \t");
242 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
243 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
249 c->name = xstrdup(name);
251 // Send the node the contents of the invitation file
254 while((result = fread(buf, 1, sizeof buf, f)))
255 sptps_send_record(&c->sptps, 0, buf, result);
256 sptps_send_record(&c->sptps, 1, buf, 0);
260 c->status.invitation_used = true;
262 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
266 bool id_h(connection_t *c, const char *request) {
267 char name[MAX_STRING_SIZE];
269 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
270 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
275 /* Check if this is a control connection */
277 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
278 c->status.control = true;
279 c->allow_request = CONTROL;
280 c->last_ping_time = now.tv_sec + 3600;
283 c->name = xstrdup("<control>");
285 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
289 if(!invitation_key) {
290 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
294 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
296 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
300 c->status.invitation = true;
301 char *mykey = ecdsa_get_base64_public_key(invitation_key);
304 if(!send_request(c, "%d %s", ACK, mykey))
308 c->protocol_minor = 2;
310 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
313 /* Check if identity is a valid name */
315 if(!check_id(name)) {
316 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
317 c->hostname, "invalid name");
321 /* If this is an outgoing connection, make sure we are connected to the right host */
324 if(strcmp(c->name, name)) {
325 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
332 c->name = xstrdup(name);
335 /* Check if version matches */
337 if(c->protocol_major != myself->connection->protocol_major) {
338 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
339 c->name, c->hostname, c->protocol_major, c->protocol_minor);
343 if(bypass_security) {
345 init_configuration(&c->config_tree);
346 c->allow_request = ACK;
351 c->protocol_minor = 0;
353 if(!c->config_tree) {
354 init_configuration(&c->config_tree);
356 if(!read_host_config(c->config_tree, c->name)) {
357 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
362 read_ecdsa_public_key(c);
364 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
365 c->protocol_minor = 1;
368 /* Forbid version rollback for nodes whose ECDSA key we know */
370 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
371 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
372 c->name, c->hostname, c->protocol_major, c->protocol_minor);
376 c->allow_request = METAKEY;
378 if(c->protocol_minor >= 2) {
379 c->allow_request = ACK;
380 char label[25 + strlen(myself->name) + strlen(c->name)];
383 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
385 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
387 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
389 return send_metakey(c);
393 bool send_metakey(connection_t *c) {
394 if(!read_rsa_public_key(c))
397 if(!(c->outcipher = cipher_open_blowfish_ofb()))
400 if(!(c->outdigest = digest_open_sha1(-1)))
403 size_t len = rsa_size(c->rsa);
406 char hexkey[2 * len + 1];
408 /* Create a random key */
412 /* The message we send must be smaller than the modulus of the RSA key.
413 By definition, for a key of k bits, the following formula holds:
415 2^(k-1) <= modulus < 2^(k)
417 Where ^ means "to the power of", not "xor".
418 This means that to be sure, we must choose our message < 2^(k-1).
419 This can be done by setting the most significant bit to zero.
424 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
427 if(debug_level >= DEBUG_SCARY_THINGS) {
428 bin2hex(key, hexkey, len);
429 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
432 /* Encrypt the random data
434 We do not use one of the PKCS padding schemes here.
435 This is allowed, because we encrypt a totally random string
436 with a length equal to that of the modulus of the RSA key.
439 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
440 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
444 /* Convert the encrypted random data to a hexadecimal formatted string */
446 bin2hex(enckey, hexkey, len);
448 /* Send the meta key */
450 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
451 cipher_get_nid(c->outcipher),
452 digest_get_nid(c->outdigest), c->outmaclength,
453 c->outcompression, hexkey);
455 c->status.encryptout = true;
459 bool metakey_h(connection_t *c, const char *request) {
460 char hexkey[MAX_STRING_SIZE];
461 int cipher, digest, maclength, compression;
462 size_t len = rsa_size(myself->connection->rsa);
466 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
467 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
471 /* Convert the challenge from hexadecimal back to binary */
473 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
475 /* Check if the length of the meta key is all right */
478 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
482 /* Decrypt the meta key */
484 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
485 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
489 if(debug_level >= DEBUG_SCARY_THINGS) {
490 bin2hex(key, hexkey, len);
491 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
494 /* Check and lookup cipher and digest algorithms */
496 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
497 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
501 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
502 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
506 c->status.decryptin = true;
508 c->allow_request = CHALLENGE;
510 return send_challenge(c);
513 bool send_challenge(connection_t *c) {
514 size_t len = rsa_size(c->rsa);
515 char buffer[len * 2 + 1];
518 c->hischallenge = xrealloc(c->hischallenge, len);
520 /* Copy random data to the buffer */
522 randomize(c->hischallenge, len);
526 bin2hex(c->hischallenge, buffer, len);
528 /* Send the challenge */
530 return send_request(c, "%d %s", CHALLENGE, buffer);
533 bool challenge_h(connection_t *c, const char *request) {
534 char buffer[MAX_STRING_SIZE];
535 size_t len = rsa_size(myself->connection->rsa);
536 size_t digestlen = digest_length(c->indigest);
537 char digest[digestlen];
539 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
540 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
544 /* Convert the challenge from hexadecimal back to binary */
546 int inlen = hex2bin(buffer, buffer, sizeof buffer);
548 /* Check if the length of the challenge is all right */
551 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
555 /* Calculate the hash from the challenge we received */
557 if(!digest_create(c->indigest, buffer, len, digest))
560 /* Convert the hash to a hexadecimal formatted string */
562 bin2hex(digest, buffer, digestlen);
566 c->allow_request = CHAL_REPLY;
568 return send_request(c, "%d %s", CHAL_REPLY, buffer);
571 bool chal_reply_h(connection_t *c, const char *request) {
572 char hishash[MAX_STRING_SIZE];
574 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
575 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
580 /* Convert the hash to binary format */
582 int inlen = hex2bin(hishash, hishash, sizeof hishash);
584 /* Check if the length of the hash is all right */
586 if(inlen != digest_length(c->outdigest)) {
587 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
592 /* Verify the hash */
594 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
595 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
599 /* Identity has now been positively verified.
600 Send an acknowledgement with the rest of the information needed.
603 free(c->hischallenge);
604 c->hischallenge = NULL;
605 c->allow_request = ACK;
610 static bool send_upgrade(connection_t *c) {
611 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
612 * but doesn't know our key yet. So send it now. */
614 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
619 bool result = send_request(c, "%d %s", ACK, pubkey);
624 bool send_ack(connection_t *c) {
625 if(c->protocol_minor == 1)
626 return send_upgrade(c);
628 /* ACK message contains rest of the information the other end needs
629 to create node_t and edge_t structures. */
634 /* Estimate weight */
636 gettimeofday(&now, NULL);
637 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
639 /* Check some options */
641 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
642 c->options |= OPTION_INDIRECT;
644 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
645 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
647 if(myself->options & OPTION_PMTU_DISCOVERY)
648 c->options |= OPTION_PMTU_DISCOVERY;
650 choice = myself->options & OPTION_CLAMP_MSS;
651 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
653 c->options |= OPTION_CLAMP_MSS;
655 get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
657 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
660 static void send_everything(connection_t *c) {
661 /* Send all known subnets and edges */
663 if(disablebuggypeers) {
666 char pad[MAXBUFSIZE - MAXSIZE];
669 memset(&zeropkt, 0, sizeof zeropkt);
670 zeropkt.pkt.len = MAXBUFSIZE;
671 send_tcppacket(c, &zeropkt.pkt);
675 for splay_each(subnet_t, s, myself->subnet_tree)
676 send_add_subnet(c, s);
681 for splay_each(node_t, n, node_tree) {
682 for splay_each(subnet_t, s, n->subnet_tree)
683 send_add_subnet(c, s);
685 for splay_each(edge_t, e, n->edge_tree)
690 static bool upgrade_h(connection_t *c, const char *request) {
691 char pubkey[MAX_STRING_SIZE];
693 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
694 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
698 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
699 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
703 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
704 append_config_file(c->name, "ECDSAPublicKey", pubkey);
705 c->allow_request = TERMREQ;
706 return send_termreq(c);
709 bool ack_h(connection_t *c, const char *request) {
710 if(c->protocol_minor == 1)
711 return upgrade_h(c, request);
713 char hisport[MAX_STRING_SIZE];
720 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
721 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
726 /* Check if we already have a node_t for him */
728 n = lookup_node(c->name);
732 n->name = xstrdup(c->name);
736 /* Oh dear, we already have a connection to this node. */
737 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
739 if(n->connection->outgoing) {
741 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
743 c->outgoing = n->connection->outgoing;
745 n->connection->outgoing = NULL;
748 terminate_connection(n->connection, false);
749 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
756 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
757 c->options &= ~OPTION_PMTU_DISCOVERY;
758 options &= ~OPTION_PMTU_DISCOVERY;
760 c->options |= options;
762 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
765 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
768 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
770 c->options |= OPTION_CLAMP_MSS;
772 c->options &= ~OPTION_CLAMP_MSS;
775 /* Activate this connection */
777 c->allow_request = ALL;
778 c->status.active = true;
780 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
783 /* Send him everything we know */
787 /* Create an edge_t for this connection */
789 c->edge = new_edge();
790 c->edge->from = myself;
792 sockaddr2str(&c->address, &hisaddress, NULL);
793 c->edge->address = str2sockaddr(hisaddress, hisport);
795 c->edge->weight = (weight + c->estimated_weight) / 2;
796 c->edge->connection = c;
797 c->edge->options = c->options;
801 /* Notify everyone of the new edge */
804 send_add_edge(c, c->edge);
806 send_add_edge(everyone, c->edge);
808 /* Run MST and SSSP algorithms */