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);
180 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
181 connection_t *c = handle;
186 if(type == 1 && c->status.invitation_used)
187 return finalize_invitation(c, data, len);
189 if(type != 0 || len != 18 || c->status.invitation_used)
193 b64encode_urlsafe(data, cookie, 18);
195 char filename[PATH_MAX], usedname[PATH_MAX];
196 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
197 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
199 // Atomically rename the invitation file
200 if(rename(filename, usedname)) {
202 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
204 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
208 // Open the renamed file
209 FILE *f = fopen(usedname, "r");
211 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
215 // Read the new node's Name from the file
217 fgets(buf, sizeof buf, f);
219 buf[strlen(buf) - 1] = 0;
221 len = strcspn(buf, " \t=");
222 char *name = buf + len;
223 name += strspn(name, " \t");
226 name += strspn(name, " \t");
230 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
231 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
237 c->name = xstrdup(name);
239 // Send the node the contents of the invitation file
242 while((result = fread(buf, 1, sizeof buf, f)))
243 sptps_send_record(&c->sptps, 0, buf, result);
244 sptps_send_record(&c->sptps, 1, buf, 0);
248 c->status.invitation_used = true;
250 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
254 bool id_h(connection_t *c, const char *request) {
255 char name[MAX_STRING_SIZE];
257 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
258 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
263 /* Check if this is a control connection */
265 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
266 c->status.control = true;
267 c->allow_request = CONTROL;
268 c->last_ping_time = now.tv_sec + 3600;
271 c->name = xstrdup("<control>");
273 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
277 if(!invitation_key) {
278 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
282 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
284 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
288 c->status.invitation = true;
289 char *mykey = ecdsa_get_base64_public_key(invitation_key);
292 if(!send_request(c, "%d %s", ACK, mykey))
296 c->protocol_minor = 2;
298 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
301 /* Check if identity is a valid name */
303 if(!check_id(name)) {
304 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
305 c->hostname, "invalid name");
309 /* If this is an outgoing connection, make sure we are connected to the right host */
312 if(strcmp(c->name, name)) {
313 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
320 c->name = xstrdup(name);
323 /* Check if version matches */
325 if(c->protocol_major != myself->connection->protocol_major) {
326 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
327 c->name, c->hostname, c->protocol_major, c->protocol_minor);
331 if(bypass_security) {
333 init_configuration(&c->config_tree);
334 c->allow_request = ACK;
339 c->protocol_minor = 0;
341 if(!c->config_tree) {
342 init_configuration(&c->config_tree);
344 if(!read_host_config(c->config_tree, c->name)) {
345 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
349 if(experimental && c->protocol_minor >= 2) {
350 if(!read_ecdsa_public_key(c))
354 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
355 c->protocol_minor = 1;
358 c->allow_request = METAKEY;
360 if(c->protocol_minor >= 2) {
361 c->allow_request = ACK;
362 char label[25 + strlen(myself->name) + strlen(c->name)];
365 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
367 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
369 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
371 return send_metakey(c);
375 bool send_metakey(connection_t *c) {
376 if(!read_rsa_public_key(c))
379 if(!(c->outcipher = cipher_open_blowfish_ofb()))
382 if(!(c->outdigest = digest_open_sha1(-1)))
385 size_t len = rsa_size(c->rsa);
388 char hexkey[2 * len + 1];
390 /* Create a random key */
394 /* The message we send must be smaller than the modulus of the RSA key.
395 By definition, for a key of k bits, the following formula holds:
397 2^(k-1) <= modulus < 2^(k)
399 Where ^ means "to the power of", not "xor".
400 This means that to be sure, we must choose our message < 2^(k-1).
401 This can be done by setting the most significant bit to zero.
406 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
409 if(debug_level >= DEBUG_SCARY_THINGS) {
410 bin2hex(key, hexkey, len);
411 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
414 /* Encrypt the random data
416 We do not use one of the PKCS padding schemes here.
417 This is allowed, because we encrypt a totally random string
418 with a length equal to that of the modulus of the RSA key.
421 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
422 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
426 /* Convert the encrypted random data to a hexadecimal formatted string */
428 bin2hex(enckey, hexkey, len);
430 /* Send the meta key */
432 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
433 cipher_get_nid(c->outcipher),
434 digest_get_nid(c->outdigest), c->outmaclength,
435 c->outcompression, hexkey);
437 c->status.encryptout = true;
441 bool metakey_h(connection_t *c, const char *request) {
442 char hexkey[MAX_STRING_SIZE];
443 int cipher, digest, maclength, compression;
444 size_t len = rsa_size(myself->connection->rsa);
448 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
449 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
453 /* Convert the challenge from hexadecimal back to binary */
455 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
457 /* Check if the length of the meta key is all right */
460 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
464 /* Decrypt the meta key */
466 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
467 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
471 if(debug_level >= DEBUG_SCARY_THINGS) {
472 bin2hex(key, hexkey, len);
473 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
476 /* Check and lookup cipher and digest algorithms */
478 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
479 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
483 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
484 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
488 c->status.decryptin = true;
490 c->allow_request = CHALLENGE;
492 return send_challenge(c);
495 bool send_challenge(connection_t *c) {
496 size_t len = rsa_size(c->rsa);
497 char buffer[len * 2 + 1];
500 c->hischallenge = xrealloc(c->hischallenge, len);
502 /* Copy random data to the buffer */
504 randomize(c->hischallenge, len);
508 bin2hex(c->hischallenge, buffer, len);
510 /* Send the challenge */
512 return send_request(c, "%d %s", CHALLENGE, buffer);
515 bool challenge_h(connection_t *c, const char *request) {
516 char buffer[MAX_STRING_SIZE];
517 size_t len = rsa_size(myself->connection->rsa);
518 size_t digestlen = digest_length(c->indigest);
519 char digest[digestlen];
521 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
522 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
526 /* Convert the challenge from hexadecimal back to binary */
528 int inlen = hex2bin(buffer, buffer, sizeof buffer);
530 /* Check if the length of the challenge is all right */
533 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
537 /* Calculate the hash from the challenge we received */
539 if(!digest_create(c->indigest, buffer, len, digest))
542 /* Convert the hash to a hexadecimal formatted string */
544 bin2hex(digest, buffer, digestlen);
548 c->allow_request = CHAL_REPLY;
550 return send_request(c, "%d %s", CHAL_REPLY, buffer);
553 bool chal_reply_h(connection_t *c, const char *request) {
554 char hishash[MAX_STRING_SIZE];
556 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
557 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
562 /* Convert the hash to binary format */
564 int inlen = hex2bin(hishash, hishash, sizeof hishash);
566 /* Check if the length of the hash is all right */
568 if(inlen != digest_length(c->outdigest)) {
569 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
574 /* Verify the hash */
576 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
577 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
581 /* Identity has now been positively verified.
582 Send an acknowledgement with the rest of the information needed.
585 free(c->hischallenge);
586 c->hischallenge = NULL;
587 c->allow_request = ACK;
592 static bool send_upgrade(connection_t *c) {
593 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
594 * but doesn't know our key yet. So send it now. */
596 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
601 bool result = send_request(c, "%d %s", ACK, pubkey);
606 bool send_ack(connection_t *c) {
607 if(c->protocol_minor == 1)
608 return send_upgrade(c);
610 /* ACK message contains rest of the information the other end needs
611 to create node_t and edge_t structures. */
616 /* Estimate weight */
618 gettimeofday(&now, NULL);
619 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
621 /* Check some options */
623 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
624 c->options |= OPTION_INDIRECT;
626 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
627 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
629 if(myself->options & OPTION_PMTU_DISCOVERY)
630 c->options |= OPTION_PMTU_DISCOVERY;
632 choice = myself->options & OPTION_CLAMP_MSS;
633 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
635 c->options |= OPTION_CLAMP_MSS;
637 get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
639 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
642 static void send_everything(connection_t *c) {
643 /* Send all known subnets and edges */
645 if(disablebuggypeers) {
648 char pad[MAXBUFSIZE - MAXSIZE];
651 memset(&zeropkt, 0, sizeof zeropkt);
652 zeropkt.pkt.len = MAXBUFSIZE;
653 send_tcppacket(c, &zeropkt.pkt);
657 for splay_each(subnet_t, s, myself->subnet_tree)
658 send_add_subnet(c, s);
663 for splay_each(node_t, n, node_tree) {
664 for splay_each(subnet_t, s, n->subnet_tree)
665 send_add_subnet(c, s);
667 for splay_each(edge_t, e, n->edge_tree)
672 static bool upgrade_h(connection_t *c, const char *request) {
673 char pubkey[MAX_STRING_SIZE];
675 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
676 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
680 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
681 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
685 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
686 append_config_file(c->name, "ECDSAPublicKey", pubkey);
687 c->allow_request = TERMREQ;
688 return send_termreq(c);
691 bool ack_h(connection_t *c, const char *request) {
692 if(c->protocol_minor == 1)
693 return upgrade_h(c, request);
695 char hisport[MAX_STRING_SIZE];
702 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
703 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
708 /* Check if we already have a node_t for him */
710 n = lookup_node(c->name);
714 n->name = xstrdup(c->name);
718 /* Oh dear, we already have a connection to this node. */
719 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
721 if(n->connection->outgoing) {
723 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
725 c->outgoing = n->connection->outgoing;
727 n->connection->outgoing = NULL;
730 terminate_connection(n->connection, false);
731 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
738 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
739 c->options &= ~OPTION_PMTU_DISCOVERY;
740 options &= ~OPTION_PMTU_DISCOVERY;
742 c->options |= options;
744 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
747 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
750 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
752 c->options |= OPTION_CLAMP_MSS;
754 c->options &= ~OPTION_CLAMP_MSS;
757 /* Activate this connection */
759 c->allow_request = ALL;
760 c->status.active = true;
762 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
765 /* Send him everything we know */
769 /* Create an edge_t for this connection */
771 c->edge = new_edge();
772 c->edge->from = myself;
774 sockaddr2str(&c->address, &hisaddress, NULL);
775 c->edge->address = str2sockaddr(hisaddress, hisport);
777 c->edge->weight = (weight + c->estimated_weight) / 2;
778 c->edge->connection = c;
779 c->edge->options = c->options;
783 /* Notify everyone of the new edge */
786 send_add_edge(c, c->edge);
788 send_add_edge(everyone, c->edge);
790 /* Run MST and SSSP algorithms */