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"
43 ecdsa_t *invitation_key = NULL;
45 static bool send_proxyrequest(connection_t *c) {
51 sockaddr2str(&c->address, &host, &port);
52 send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
58 if(c->address.sa.sa_family != AF_INET) {
59 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
62 char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
65 memcpy(s4req + 2, &c->address.in.sin_port, 2);
66 memcpy(s4req + 4, &c->address.in.sin_addr, 4);
68 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
69 s4req[sizeof s4req - 1] = 0;
71 return send_meta(c, s4req, sizeof s4req);
74 int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
77 len += 3 + strlen(proxyuser) + strlen(proxypass);
85 s5req[i++] = strlen(proxyuser);
86 memcpy(s5req + i, proxyuser, strlen(proxyuser));
87 i += strlen(proxyuser);
88 s5req[i++] = strlen(proxypass);
89 memcpy(s5req + i, proxypass, strlen(proxypass));
90 i += strlen(proxypass);
98 if(c->address.sa.sa_family == AF_INET) {
100 memcpy(s5req + i, &c->address.in.sin_addr, 4);
102 memcpy(s5req + i, &c->address.in.sin_port, 2);
105 } else if(c->address.sa.sa_family == AF_INET6) {
107 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
109 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
113 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
118 return send_meta(c, s5req, sizeof s5req);
121 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
126 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
131 bool send_id(connection_t *c) {
132 gettimeofday(&c->start, NULL);
137 if(c->outgoing && !read_ecdsa_public_key(c))
140 minor = myself->connection->protocol_minor;
143 if(proxytype && c->outgoing)
144 if(!send_proxyrequest(c))
147 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
150 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
151 if(strchr(data, '\n')) {
152 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
156 // Create a new host config file
157 char filename[PATH_MAX];
158 snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
159 if(!access(filename, F_OK)) {
160 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
164 FILE *f = fopen(filename, "w");
166 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
170 fprintf(f, "ECDSAPublicKey = %s\n", data);
173 logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
175 //TODO: callback to application to inform of an accepted invitation
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 an invitation */
278 if(!invitation_key) {
279 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
283 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
285 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
289 c->status.invitation = true;
290 char *mykey = ecdsa_get_base64_public_key(invitation_key);
293 if(!send_request(c, "%d %s", ACK, mykey))
297 c->protocol_minor = 2;
299 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
302 /* Check if identity is a valid name */
304 if(!check_id(name)) {
305 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
306 c->hostname, "invalid name");
310 /* If this is an outgoing connection, make sure we are connected to the right host */
313 if(strcmp(c->name, name)) {
314 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
321 c->name = xstrdup(name);
324 /* Check if version matches */
326 if(c->protocol_major != myself->connection->protocol_major) {
327 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
328 c->name, c->hostname, c->protocol_major, c->protocol_minor);
332 if(bypass_security) {
334 init_configuration(&c->config_tree);
335 c->allow_request = ACK;
340 c->protocol_minor = 0;
342 if(!c->config_tree) {
343 init_configuration(&c->config_tree);
345 if(!read_host_config(c->config_tree, c->name)) {
346 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
351 read_ecdsa_public_key(c);
353 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
354 c->protocol_minor = 1;
357 /* Forbid version rollback for nodes whose ECDSA key we know */
359 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
360 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
361 c->name, c->hostname, c->protocol_major, c->protocol_minor);
365 c->allow_request = METAKEY;
367 if(c->protocol_minor >= 2) {
368 c->allow_request = ACK;
369 char label[25 + strlen(myself->name) + strlen(c->name)];
372 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
374 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
376 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
378 return send_metakey(c);
382 bool send_metakey(connection_t *c) {
383 if(!read_rsa_public_key(c))
386 if(!(c->outcipher = cipher_open_blowfish_ofb()))
389 if(!(c->outdigest = digest_open_sha1(-1)))
392 size_t len = rsa_size(c->rsa);
395 char hexkey[2 * len + 1];
397 /* Create a random key */
401 /* The message we send must be smaller than the modulus of the RSA key.
402 By definition, for a key of k bits, the following formula holds:
404 2^(k-1) <= modulus < 2^(k)
406 Where ^ means "to the power of", not "xor".
407 This means that to be sure, we must choose our message < 2^(k-1).
408 This can be done by setting the most significant bit to zero.
413 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
416 if(debug_level >= DEBUG_SCARY_THINGS) {
417 bin2hex(key, hexkey, len);
418 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
421 /* Encrypt the random data
423 We do not use one of the PKCS padding schemes here.
424 This is allowed, because we encrypt a totally random string
425 with a length equal to that of the modulus of the RSA key.
428 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
429 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
433 /* Convert the encrypted random data to a hexadecimal formatted string */
435 bin2hex(enckey, hexkey, len);
437 /* Send the meta key */
439 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
440 cipher_get_nid(c->outcipher),
441 digest_get_nid(c->outdigest), c->outmaclength,
442 c->outcompression, hexkey);
444 c->status.encryptout = true;
448 bool metakey_h(connection_t *c, const char *request) {
449 char hexkey[MAX_STRING_SIZE];
450 int cipher, digest, maclength, compression;
451 size_t len = rsa_size(myself->connection->rsa);
455 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
456 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
460 /* Convert the challenge from hexadecimal back to binary */
462 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
464 /* Check if the length of the meta key is all right */
467 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
471 /* Decrypt the meta key */
473 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
474 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
478 if(debug_level >= DEBUG_SCARY_THINGS) {
479 bin2hex(key, hexkey, len);
480 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
483 /* Check and lookup cipher and digest algorithms */
485 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
486 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
490 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
491 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
495 c->status.decryptin = true;
497 c->allow_request = CHALLENGE;
499 return send_challenge(c);
502 bool send_challenge(connection_t *c) {
503 size_t len = rsa_size(c->rsa);
504 char buffer[len * 2 + 1];
507 c->hischallenge = xrealloc(c->hischallenge, len);
509 /* Copy random data to the buffer */
511 randomize(c->hischallenge, len);
515 bin2hex(c->hischallenge, buffer, len);
517 /* Send the challenge */
519 return send_request(c, "%d %s", CHALLENGE, buffer);
522 bool challenge_h(connection_t *c, const char *request) {
523 char buffer[MAX_STRING_SIZE];
524 size_t len = rsa_size(myself->connection->rsa);
525 size_t digestlen = digest_length(c->indigest);
526 char digest[digestlen];
528 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
529 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
533 /* Convert the challenge from hexadecimal back to binary */
535 int inlen = hex2bin(buffer, buffer, sizeof buffer);
537 /* Check if the length of the challenge is all right */
540 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
544 /* Calculate the hash from the challenge we received */
546 if(!digest_create(c->indigest, buffer, len, digest))
549 /* Convert the hash to a hexadecimal formatted string */
551 bin2hex(digest, buffer, digestlen);
555 c->allow_request = CHAL_REPLY;
557 return send_request(c, "%d %s", CHAL_REPLY, buffer);
560 bool chal_reply_h(connection_t *c, const char *request) {
561 char hishash[MAX_STRING_SIZE];
563 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
564 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
569 /* Convert the hash to binary format */
571 int inlen = hex2bin(hishash, hishash, sizeof hishash);
573 /* Check if the length of the hash is all right */
575 if(inlen != digest_length(c->outdigest)) {
576 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
581 /* Verify the hash */
583 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
584 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
588 /* Identity has now been positively verified.
589 Send an acknowledgement with the rest of the information needed.
592 free(c->hischallenge);
593 c->hischallenge = NULL;
594 c->allow_request = ACK;
599 static bool send_upgrade(connection_t *c) {
600 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
601 * but doesn't know our key yet. So send it now. */
603 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
608 bool result = send_request(c, "%d %s", ACK, pubkey);
613 bool send_ack(connection_t *c) {
614 if(c->protocol_minor == 1)
615 return send_upgrade(c);
617 /* ACK message contains rest of the information the other end needs
618 to create node_t and edge_t structures. */
623 /* Estimate weight */
625 gettimeofday(&now, NULL);
626 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
628 /* Check some options */
630 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
631 c->options |= OPTION_INDIRECT;
633 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
634 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
636 if(myself->options & OPTION_PMTU_DISCOVERY)
637 c->options |= OPTION_PMTU_DISCOVERY;
639 choice = myself->options & OPTION_CLAMP_MSS;
640 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
642 c->options |= OPTION_CLAMP_MSS;
644 if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
645 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
647 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
650 static void send_everything(connection_t *c) {
651 /* Send all known subnets and edges */
654 if(disablebuggypeers) {
657 char pad[MAXBUFSIZE - MAXSIZE];
660 memset(&zeropkt, 0, sizeof zeropkt);
661 zeropkt.pkt.len = MAXBUFSIZE;
662 send_tcppacket(c, &zeropkt.pkt);
665 for splay_each(node_t, n, node_tree) {
666 for splay_each(edge_t, e, n->edge_tree)
671 static bool upgrade_h(connection_t *c, const char *request) {
672 char pubkey[MAX_STRING_SIZE];
674 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
675 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
679 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
680 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
684 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
685 append_config_file(c->name, "ECDSAPublicKey", pubkey);
686 c->allow_request = TERMREQ;
687 return send_termreq(c);
690 bool ack_h(connection_t *c, const char *request) {
691 if(c->protocol_minor == 1)
692 return upgrade_h(c, request);
694 char hisport[MAX_STRING_SIZE];
701 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
702 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
707 /* Check if we already have a node_t for him */
709 n = lookup_node(c->name);
713 n->name = xstrdup(c->name);
717 /* Oh dear, we already have a connection to this node. */
718 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
720 if(n->connection->outgoing) {
722 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
724 c->outgoing = n->connection->outgoing;
726 n->connection->outgoing = NULL;
729 terminate_connection(n->connection, false);
730 /* Run graph algorithm to keep things in sync */
737 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
738 c->options &= ~OPTION_PMTU_DISCOVERY;
739 options &= ~OPTION_PMTU_DISCOVERY;
741 c->options |= options;
743 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
746 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
749 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
751 c->options |= OPTION_CLAMP_MSS;
753 c->options &= ~OPTION_CLAMP_MSS;
756 /* Activate this connection */
758 c->allow_request = ALL;
759 c->status.active = true;
761 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
764 /* Send him everything we know */
768 /* Create an edge_t for this connection */
770 c->edge = new_edge();
771 c->edge->from = myself;
773 sockaddr2str(&c->address, &hisaddress, NULL);
774 c->edge->address = str2sockaddr(hisaddress, hisport);
776 c->edge->weight = (weight + c->estimated_weight) / 2;
777 c->edge->connection = c;
778 c->edge->options = c->options;
782 /* Notify everyone of the new edge */
785 send_add_edge(c, c->edge);
787 send_add_edge(everyone, c->edge);
789 /* Run MST and SSSP algorithms */