2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2014 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);
178 //TODO: callback to application to inform of an accepted invitation
180 sptps_send_record(&c->sptps, 2, data, 0);
184 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
185 connection_t *c = handle;
190 if(type == 1 && c->status.invitation_used)
191 return finalize_invitation(c, data, len);
193 if(type != 0 || len != 18 || c->status.invitation_used)
196 // Recover the filename from the cookie and the key
197 digest_t *digest = digest_open_by_name("sha256", 18);
200 char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
201 char hashbuf[18 + strlen(fingerprint)];
203 memcpy(hashbuf, data, 18);
204 memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
205 digest_create(digest, hashbuf, sizeof hashbuf, cookie);
206 b64encode_urlsafe(cookie, cookie, 18);
207 digest_close(digest);
210 char filename[PATH_MAX], usedname[PATH_MAX];
211 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
212 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
214 // Atomically rename the invitation file
215 if(rename(filename, usedname)) {
217 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
219 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
223 // Open the renamed file
224 FILE *f = fopen(usedname, "r");
226 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
230 // Read the new node's Name from the file
232 fgets(buf, sizeof buf, f);
234 buf[strlen(buf) - 1] = 0;
236 len = strcspn(buf, " \t=");
237 char *name = buf + len;
238 name += strspn(name, " \t");
241 name += strspn(name, " \t");
245 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
246 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
252 c->name = xstrdup(name);
254 // Send the node the contents of the invitation file
257 while((result = fread(buf, 1, sizeof buf, f)))
258 sptps_send_record(&c->sptps, 0, buf, result);
259 sptps_send_record(&c->sptps, 1, buf, 0);
263 c->status.invitation_used = true;
265 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
269 bool id_h(connection_t *c, const char *request) {
270 char name[MAX_STRING_SIZE];
272 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
273 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
278 /* Check if this is a control connection */
280 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
281 c->status.control = true;
282 c->allow_request = CONTROL;
283 c->last_ping_time = now.tv_sec + 3600;
286 c->name = xstrdup("<control>");
288 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
292 if(!invitation_key) {
293 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
297 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
299 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
303 c->status.invitation = true;
304 char *mykey = ecdsa_get_base64_public_key(invitation_key);
307 if(!send_request(c, "%d %s", ACK, mykey))
311 c->protocol_minor = 2;
313 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
316 /* Check if identity is a valid name */
318 if(!check_id(name)) {
319 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
320 c->hostname, "invalid name");
324 /* If this is an outgoing connection, make sure we are connected to the right host */
327 if(strcmp(c->name, name)) {
328 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
335 c->name = xstrdup(name);
338 /* Check if version matches */
340 if(c->protocol_major != myself->connection->protocol_major) {
341 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
342 c->name, c->hostname, c->protocol_major, c->protocol_minor);
346 if(bypass_security) {
348 init_configuration(&c->config_tree);
349 c->allow_request = ACK;
354 c->protocol_minor = 0;
356 if(!c->config_tree) {
357 init_configuration(&c->config_tree);
359 if(!read_host_config(c->config_tree, c->name)) {
360 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
365 read_ecdsa_public_key(c);
367 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
368 c->protocol_minor = 1;
371 /* Forbid version rollback for nodes whose ECDSA key we know */
373 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
374 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
375 c->name, c->hostname, c->protocol_major, c->protocol_minor);
379 c->allow_request = METAKEY;
381 if(c->protocol_minor >= 2) {
382 c->allow_request = ACK;
383 char label[25 + strlen(myself->name) + strlen(c->name)];
386 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
388 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
390 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
392 return send_metakey(c);
396 bool send_metakey(connection_t *c) {
397 if(!read_rsa_public_key(c))
400 if(!(c->outcipher = cipher_open_blowfish_ofb()))
403 if(!(c->outdigest = digest_open_sha1(-1)))
406 size_t len = rsa_size(c->rsa);
409 char hexkey[2 * len + 1];
411 /* Create a random key */
415 /* The message we send must be smaller than the modulus of the RSA key.
416 By definition, for a key of k bits, the following formula holds:
418 2^(k-1) <= modulus < 2^(k)
420 Where ^ means "to the power of", not "xor".
421 This means that to be sure, we must choose our message < 2^(k-1).
422 This can be done by setting the most significant bit to zero.
427 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
430 if(debug_level >= DEBUG_SCARY_THINGS) {
431 bin2hex(key, hexkey, len);
432 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
435 /* Encrypt the random data
437 We do not use one of the PKCS padding schemes here.
438 This is allowed, because we encrypt a totally random string
439 with a length equal to that of the modulus of the RSA key.
442 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
443 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
447 /* Convert the encrypted random data to a hexadecimal formatted string */
449 bin2hex(enckey, hexkey, len);
451 /* Send the meta key */
453 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
454 cipher_get_nid(c->outcipher),
455 digest_get_nid(c->outdigest), c->outmaclength,
456 c->outcompression, hexkey);
458 c->status.encryptout = true;
462 bool metakey_h(connection_t *c, const char *request) {
463 char hexkey[MAX_STRING_SIZE];
464 int cipher, digest, maclength, compression;
465 size_t len = rsa_size(myself->connection->rsa);
469 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
470 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
474 /* Convert the challenge from hexadecimal back to binary */
476 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
478 /* Check if the length of the meta key is all right */
481 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
485 /* Decrypt the meta key */
487 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
488 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
492 if(debug_level >= DEBUG_SCARY_THINGS) {
493 bin2hex(key, hexkey, len);
494 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
497 /* Check and lookup cipher and digest algorithms */
499 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
500 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
504 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
505 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
509 c->status.decryptin = true;
511 c->allow_request = CHALLENGE;
513 return send_challenge(c);
516 bool send_challenge(connection_t *c) {
517 size_t len = rsa_size(c->rsa);
518 char buffer[len * 2 + 1];
521 c->hischallenge = xrealloc(c->hischallenge, len);
523 /* Copy random data to the buffer */
525 randomize(c->hischallenge, len);
529 bin2hex(c->hischallenge, buffer, len);
531 /* Send the challenge */
533 return send_request(c, "%d %s", CHALLENGE, buffer);
536 bool challenge_h(connection_t *c, const char *request) {
537 char buffer[MAX_STRING_SIZE];
538 size_t len = rsa_size(myself->connection->rsa);
539 size_t digestlen = digest_length(c->indigest);
540 char digest[digestlen];
542 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
543 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
547 /* Convert the challenge from hexadecimal back to binary */
549 int inlen = hex2bin(buffer, buffer, sizeof buffer);
551 /* Check if the length of the challenge is all right */
554 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
558 /* Calculate the hash from the challenge we received */
560 if(!digest_create(c->indigest, buffer, len, digest))
563 /* Convert the hash to a hexadecimal formatted string */
565 bin2hex(digest, buffer, digestlen);
569 c->allow_request = CHAL_REPLY;
571 return send_request(c, "%d %s", CHAL_REPLY, buffer);
574 bool chal_reply_h(connection_t *c, const char *request) {
575 char hishash[MAX_STRING_SIZE];
577 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
578 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
583 /* Convert the hash to binary format */
585 int inlen = hex2bin(hishash, hishash, sizeof hishash);
587 /* Check if the length of the hash is all right */
589 if(inlen != digest_length(c->outdigest)) {
590 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
595 /* Verify the hash */
597 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
598 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
602 /* Identity has now been positively verified.
603 Send an acknowledgement with the rest of the information needed.
606 free(c->hischallenge);
607 c->hischallenge = NULL;
608 c->allow_request = ACK;
613 static bool send_upgrade(connection_t *c) {
614 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
615 * but doesn't know our key yet. So send it now. */
617 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
622 bool result = send_request(c, "%d %s", ACK, pubkey);
627 bool send_ack(connection_t *c) {
628 if(c->protocol_minor == 1)
629 return send_upgrade(c);
631 /* ACK message contains rest of the information the other end needs
632 to create node_t and edge_t structures. */
637 /* Estimate weight */
639 gettimeofday(&now, NULL);
640 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
642 /* Check some options */
644 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
645 c->options |= OPTION_INDIRECT;
647 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
648 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
650 if(myself->options & OPTION_PMTU_DISCOVERY)
651 c->options |= OPTION_PMTU_DISCOVERY;
653 choice = myself->options & OPTION_CLAMP_MSS;
654 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
656 c->options |= OPTION_CLAMP_MSS;
658 if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
659 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
661 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
664 static void send_everything(connection_t *c) {
665 /* Send all known subnets and edges */
668 if(disablebuggypeers) {
671 char pad[MAXBUFSIZE - MAXSIZE];
674 memset(&zeropkt, 0, sizeof zeropkt);
675 zeropkt.pkt.len = MAXBUFSIZE;
676 send_tcppacket(c, &zeropkt.pkt);
679 for splay_each(node_t, n, node_tree) {
680 for splay_each(edge_t, e, n->edge_tree)
685 static bool upgrade_h(connection_t *c, const char *request) {
686 char pubkey[MAX_STRING_SIZE];
688 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
689 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
693 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
694 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
698 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
699 append_config_file(c->name, "ECDSAPublicKey", pubkey);
700 c->allow_request = TERMREQ;
701 return send_termreq(c);
704 bool ack_h(connection_t *c, const char *request) {
705 if(c->protocol_minor == 1)
706 return upgrade_h(c, request);
708 char hisport[MAX_STRING_SIZE];
715 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
716 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
721 /* Check if we already have a node_t for him */
723 n = lookup_node(c->name);
727 n->name = xstrdup(c->name);
731 /* Oh dear, we already have a connection to this node. */
732 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
734 if(n->connection->outgoing) {
736 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
738 c->outgoing = n->connection->outgoing;
740 n->connection->outgoing = NULL;
743 terminate_connection(n->connection, false);
744 /* Run graph algorithm to keep things in sync */
751 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
752 c->options &= ~OPTION_PMTU_DISCOVERY;
753 options &= ~OPTION_PMTU_DISCOVERY;
755 c->options |= options;
757 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
760 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
763 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
765 c->options |= OPTION_CLAMP_MSS;
767 c->options &= ~OPTION_CLAMP_MSS;
770 /* Activate this connection */
772 c->allow_request = ALL;
773 c->status.active = true;
775 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
778 /* Send him everything we know */
782 /* Create an edge_t for this connection */
784 c->edge = new_edge();
785 c->edge->from = myself;
787 sockaddr2str(&c->address, &hisaddress, NULL);
788 c->edge->address = str2sockaddr(hisaddress, hisport);
790 c->edge->weight = (weight + c->estimated_weight) / 2;
791 c->edge->connection = c;
792 c->edge->options = c->options;
796 /* Notify everyone of the new edge */
799 send_add_edge(c, c->edge);
801 send_add_edge(everyone, c->edge);
803 /* Run MST and SSSP algorithms */