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"
48 ecdsa_t *invitation_key = NULL;
50 static bool send_proxyrequest(connection_t *c) {
56 sockaddr2str(&c->address, &host, &port);
57 send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
63 if(c->address.sa.sa_family != AF_INET) {
64 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
67 char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
70 memcpy(s4req + 2, &c->address.in.sin_port, 2);
71 memcpy(s4req + 4, &c->address.in.sin_addr, 4);
73 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
74 s4req[sizeof s4req - 1] = 0;
76 return send_meta(c, s4req, sizeof s4req);
79 int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
82 len += 3 + strlen(proxyuser) + strlen(proxypass);
90 s5req[i++] = strlen(proxyuser);
91 memcpy(s5req + i, proxyuser, strlen(proxyuser));
92 i += strlen(proxyuser);
93 s5req[i++] = strlen(proxypass);
94 memcpy(s5req + i, proxypass, strlen(proxypass));
95 i += strlen(proxypass);
103 if(c->address.sa.sa_family == AF_INET) {
105 memcpy(s5req + i, &c->address.in.sin_addr, 4);
107 memcpy(s5req + i, &c->address.in.sin_port, 2);
110 } else if(c->address.sa.sa_family == AF_INET6) {
112 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
114 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
118 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
123 return send_meta(c, s5req, sizeof s5req);
126 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
131 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
136 bool send_id(connection_t *c) {
137 gettimeofday(&c->start, NULL);
142 if(c->outgoing && !read_ecdsa_public_key(c))
145 minor = myself->connection->protocol_minor;
148 if(proxytype && c->outgoing)
149 if(!send_proxyrequest(c))
152 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
155 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
156 if(strchr(data, '\n')) {
157 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
161 // Create a new host config file
162 char filename[PATH_MAX];
163 snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
164 if(!access(filename, F_OK)) {
165 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
169 FILE *f = fopen(filename, "w");
171 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
175 fprintf(f, "ECDSAPublicKey = %s\n", data);
178 logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
180 // Call invitation-accepted script
181 char *envp[7] = {NULL};
182 char *address, *port;
184 xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
185 xasprintf(&envp[1], "DEVICE=%s", device ? : "");
186 xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
187 xasprintf(&envp[3], "NODE=%s", c->name);
188 sockaddr2str(&c->address, &address, &port);
189 xasprintf(&envp[4], "REMOTEADDRESS=%s", address);
190 xasprintf(&envp[5], "NAME=%s", myself->name);
192 execute_script("invitation-accepted", envp);
194 for(int i = 0; envp[i] && i < 7; i++)
197 sptps_send_record(&c->sptps, 2, data, 0);
201 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
202 connection_t *c = handle;
207 if(type == 1 && c->status.invitation_used)
208 return finalize_invitation(c, data, len);
210 if(type != 0 || len != 18 || c->status.invitation_used)
213 // Recover the filename from the cookie and the key
214 digest_t *digest = digest_open_by_name("sha256", 18);
217 char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
218 char hashbuf[18 + strlen(fingerprint)];
220 memcpy(hashbuf, data, 18);
221 memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
222 digest_create(digest, hashbuf, sizeof hashbuf, cookie);
223 b64encode_urlsafe(cookie, cookie, 18);
224 digest_close(digest);
227 char filename[PATH_MAX], usedname[PATH_MAX];
228 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
229 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
231 // Atomically rename the invitation file
232 if(rename(filename, usedname)) {
234 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
236 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
240 // Open the renamed file
241 FILE *f = fopen(usedname, "r");
243 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
247 // Read the new node's Name from the file
249 fgets(buf, sizeof buf, f);
251 buf[strlen(buf) - 1] = 0;
253 len = strcspn(buf, " \t=");
254 char *name = buf + len;
255 name += strspn(name, " \t");
258 name += strspn(name, " \t");
262 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
263 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
269 c->name = xstrdup(name);
271 // Send the node the contents of the invitation file
274 while((result = fread(buf, 1, sizeof buf, f)))
275 sptps_send_record(&c->sptps, 0, buf, result);
276 sptps_send_record(&c->sptps, 1, buf, 0);
280 c->status.invitation_used = true;
282 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
286 bool id_h(connection_t *c, const char *request) {
287 char name[MAX_STRING_SIZE];
289 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
290 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
295 /* Check if this is a control connection */
297 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
298 c->status.control = true;
299 c->allow_request = CONTROL;
300 c->last_ping_time = now.tv_sec + 3600;
303 c->name = xstrdup("<control>");
305 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
309 if(!invitation_key) {
310 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
314 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
316 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
320 c->status.invitation = true;
321 char *mykey = ecdsa_get_base64_public_key(invitation_key);
324 if(!send_request(c, "%d %s", ACK, mykey))
328 c->protocol_minor = 2;
330 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
333 /* Check if identity is a valid name */
335 if(!check_id(name)) {
336 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
337 c->hostname, "invalid name");
341 /* If this is an outgoing connection, make sure we are connected to the right host */
344 if(strcmp(c->name, name)) {
345 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
352 c->name = xstrdup(name);
355 /* Check if version matches */
357 if(c->protocol_major != myself->connection->protocol_major) {
358 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
359 c->name, c->hostname, c->protocol_major, c->protocol_minor);
363 if(bypass_security) {
365 init_configuration(&c->config_tree);
366 c->allow_request = ACK;
371 c->protocol_minor = 0;
373 if(!c->config_tree) {
374 init_configuration(&c->config_tree);
376 if(!read_host_config(c->config_tree, c->name)) {
377 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
382 if(!read_ecdsa_public_key(c))
385 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
386 c->protocol_minor = 1;
389 /* Forbid version rollback for nodes whose ECDSA key we know */
391 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
392 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
393 c->name, c->hostname, c->protocol_major, c->protocol_minor);
397 c->allow_request = METAKEY;
399 if(c->protocol_minor >= 2) {
400 c->allow_request = ACK;
401 char label[25 + strlen(myself->name) + strlen(c->name)];
404 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
406 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
408 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
410 return send_metakey(c);
414 bool send_metakey(connection_t *c) {
415 if(!read_rsa_public_key(c))
418 if(!(c->outcipher = cipher_open_blowfish_ofb()))
421 if(!(c->outdigest = digest_open_sha1(-1)))
424 size_t len = rsa_size(c->rsa);
427 char hexkey[2 * len + 1];
429 /* Create a random key */
433 /* The message we send must be smaller than the modulus of the RSA key.
434 By definition, for a key of k bits, the following formula holds:
436 2^(k-1) <= modulus < 2^(k)
438 Where ^ means "to the power of", not "xor".
439 This means that to be sure, we must choose our message < 2^(k-1).
440 This can be done by setting the most significant bit to zero.
445 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
448 if(debug_level >= DEBUG_SCARY_THINGS) {
449 bin2hex(key, hexkey, len);
450 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
453 /* Encrypt the random data
455 We do not use one of the PKCS padding schemes here.
456 This is allowed, because we encrypt a totally random string
457 with a length equal to that of the modulus of the RSA key.
460 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
461 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
465 /* Convert the encrypted random data to a hexadecimal formatted string */
467 bin2hex(enckey, hexkey, len);
469 /* Send the meta key */
471 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
472 cipher_get_nid(c->outcipher),
473 digest_get_nid(c->outdigest), c->outmaclength,
474 c->outcompression, hexkey);
476 c->status.encryptout = true;
480 bool metakey_h(connection_t *c, const char *request) {
481 char hexkey[MAX_STRING_SIZE];
482 int cipher, digest, maclength, compression;
483 size_t len = rsa_size(myself->connection->rsa);
487 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
488 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
492 /* Convert the challenge from hexadecimal back to binary */
494 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
496 /* Check if the length of the meta key is all right */
499 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
503 /* Decrypt the meta key */
505 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
506 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
510 if(debug_level >= DEBUG_SCARY_THINGS) {
511 bin2hex(key, hexkey, len);
512 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
515 /* Check and lookup cipher and digest algorithms */
517 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
518 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
522 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
523 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
527 c->status.decryptin = true;
529 c->allow_request = CHALLENGE;
531 return send_challenge(c);
534 bool send_challenge(connection_t *c) {
535 size_t len = rsa_size(c->rsa);
536 char buffer[len * 2 + 1];
539 c->hischallenge = xrealloc(c->hischallenge, len);
541 /* Copy random data to the buffer */
543 randomize(c->hischallenge, len);
547 bin2hex(c->hischallenge, buffer, len);
549 /* Send the challenge */
551 return send_request(c, "%d %s", CHALLENGE, buffer);
554 bool challenge_h(connection_t *c, const char *request) {
555 char buffer[MAX_STRING_SIZE];
556 size_t len = rsa_size(myself->connection->rsa);
557 size_t digestlen = digest_length(c->indigest);
558 char digest[digestlen];
560 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
561 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
565 /* Convert the challenge from hexadecimal back to binary */
567 int inlen = hex2bin(buffer, buffer, sizeof buffer);
569 /* Check if the length of the challenge is all right */
572 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
576 /* Calculate the hash from the challenge we received */
578 if(!digest_create(c->indigest, buffer, len, digest))
581 /* Convert the hash to a hexadecimal formatted string */
583 bin2hex(digest, buffer, digestlen);
587 c->allow_request = CHAL_REPLY;
589 return send_request(c, "%d %s", CHAL_REPLY, buffer);
592 bool chal_reply_h(connection_t *c, const char *request) {
593 char hishash[MAX_STRING_SIZE];
595 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
596 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
601 /* Convert the hash to binary format */
603 int inlen = hex2bin(hishash, hishash, sizeof hishash);
605 /* Check if the length of the hash is all right */
607 if(inlen != digest_length(c->outdigest)) {
608 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
613 /* Verify the hash */
615 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
616 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
620 /* Identity has now been positively verified.
621 Send an acknowledgement with the rest of the information needed.
624 free(c->hischallenge);
625 c->hischallenge = NULL;
626 c->allow_request = ACK;
631 static bool send_upgrade(connection_t *c) {
632 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
633 * but doesn't know our key yet. So send it now. */
635 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
640 bool result = send_request(c, "%d %s", ACK, pubkey);
645 bool send_ack(connection_t *c) {
646 if(c->protocol_minor == 1)
647 return send_upgrade(c);
649 /* ACK message contains rest of the information the other end needs
650 to create node_t and edge_t structures. */
655 /* Estimate weight */
657 gettimeofday(&now, NULL);
658 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
660 /* Check some options */
662 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
663 c->options |= OPTION_INDIRECT;
665 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
666 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
668 if(myself->options & OPTION_PMTU_DISCOVERY)
669 c->options |= OPTION_PMTU_DISCOVERY;
671 choice = myself->options & OPTION_CLAMP_MSS;
672 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
674 c->options |= OPTION_CLAMP_MSS;
676 if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
677 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
679 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
682 static void send_everything(connection_t *c) {
683 /* Send all known subnets and edges */
685 if(disablebuggypeers) {
688 char pad[MAXBUFSIZE - MAXSIZE];
691 memset(&zeropkt, 0, sizeof zeropkt);
692 zeropkt.pkt.len = MAXBUFSIZE;
693 send_tcppacket(c, &zeropkt.pkt);
697 for splay_each(subnet_t, s, myself->subnet_tree)
698 send_add_subnet(c, s);
703 for splay_each(node_t, n, node_tree) {
704 for splay_each(subnet_t, s, n->subnet_tree)
705 send_add_subnet(c, s);
707 for splay_each(edge_t, e, n->edge_tree)
712 static bool upgrade_h(connection_t *c, const char *request) {
713 char pubkey[MAX_STRING_SIZE];
715 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
716 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
720 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
721 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
725 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
726 append_config_file(c->name, "ECDSAPublicKey", pubkey);
727 c->allow_request = TERMREQ;
728 return send_termreq(c);
731 bool ack_h(connection_t *c, const char *request) {
732 if(c->protocol_minor == 1)
733 return upgrade_h(c, request);
735 char hisport[MAX_STRING_SIZE];
742 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
743 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
748 /* Check if we already have a node_t for him */
750 n = lookup_node(c->name);
754 n->name = xstrdup(c->name);
758 /* Oh dear, we already have a connection to this node. */
759 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
761 if(n->connection->outgoing) {
763 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
765 c->outgoing = n->connection->outgoing;
767 n->connection->outgoing = NULL;
770 terminate_connection(n->connection, false);
771 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
778 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
779 c->options &= ~OPTION_PMTU_DISCOVERY;
780 options &= ~OPTION_PMTU_DISCOVERY;
782 c->options |= options;
784 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
787 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
790 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
792 c->options |= OPTION_CLAMP_MSS;
794 c->options &= ~OPTION_CLAMP_MSS;
797 /* Activate this connection */
799 c->allow_request = ALL;
800 c->status.active = true;
802 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
805 /* Send him everything we know */
809 /* Create an edge_t for this connection */
811 c->edge = new_edge();
812 c->edge->from = myself;
814 sockaddr2str(&c->address, &hisaddress, NULL);
815 c->edge->address = str2sockaddr(hisaddress, hisport);
817 c->edge->weight = (weight + c->estimated_weight) / 2;
818 c->edge->connection = c;
819 c->edge->options = c->options;
823 /* Notify everyone of the new edge */
826 send_add_edge(c, c->edge);
828 send_add_edge(everyone, c->edge);
830 /* Run MST and SSSP algorithms */