2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include "connection.h"
42 ecdsa_t *invitation_key = NULL;
44 static bool send_proxyrequest(connection_t *c) {
50 sockaddr2str(&c->address, &host, &port);
51 send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
57 if(c->address.sa.sa_family != AF_INET) {
58 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
61 char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
64 memcpy(s4req + 2, &c->address.in.sin_port, 2);
65 memcpy(s4req + 4, &c->address.in.sin_addr, 4);
67 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
68 s4req[sizeof s4req - 1] = 0;
70 return send_meta(c, s4req, sizeof s4req);
73 int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
76 len += 3 + strlen(proxyuser) + strlen(proxypass);
84 s5req[i++] = strlen(proxyuser);
85 memcpy(s5req + i, proxyuser, strlen(proxyuser));
86 i += strlen(proxyuser);
87 s5req[i++] = strlen(proxypass);
88 memcpy(s5req + i, proxypass, strlen(proxypass));
89 i += strlen(proxypass);
97 if(c->address.sa.sa_family == AF_INET) {
99 memcpy(s5req + i, &c->address.in.sin_addr, 4);
101 memcpy(s5req + i, &c->address.in.sin_port, 2);
104 } else if(c->address.sa.sa_family == AF_INET6) {
106 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
108 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
112 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
117 return send_meta(c, s5req, sizeof s5req);
120 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
125 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
130 bool send_id(connection_t *c) {
131 gettimeofday(&c->start, NULL);
136 if(c->outgoing && !read_ecdsa_public_key(c))
139 minor = myself->connection->protocol_minor;
142 if(proxytype && c->outgoing)
143 if(!send_proxyrequest(c))
146 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
149 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
150 if(strchr(data, '\n')) {
151 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
155 // Create a new host config file
156 char filename[PATH_MAX];
157 snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
158 if(!access(filename, F_OK)) {
159 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
163 FILE *f = fopen(filename, "w");
165 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
169 fprintf(f, "ECDSAPublicKey = %s\n", data);
172 logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
174 //TODO: callback to application to inform of an accepted invitation
176 sptps_send_record(&c->sptps, 2, data, 0);
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)
192 // Recover the filename from the cookie and the key
193 digest_t *digest = digest_open_by_name("sha256", 18);
196 char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
197 char hashbuf[18 + strlen(fingerprint)];
199 memcpy(hashbuf, data, 18);
200 memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
201 digest_create(digest, hashbuf, sizeof hashbuf, cookie);
202 b64encode_urlsafe(cookie, cookie, 18);
203 digest_close(digest);
206 char filename[PATH_MAX], usedname[PATH_MAX];
207 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
208 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
210 // Atomically rename the invitation file
211 if(rename(filename, usedname)) {
213 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
215 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
219 // Open the renamed file
220 FILE *f = fopen(usedname, "r");
222 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
226 // Read the new node's Name from the file
228 fgets(buf, sizeof buf, f);
230 buf[strlen(buf) - 1] = 0;
232 len = strcspn(buf, " \t=");
233 char *name = buf + len;
234 name += strspn(name, " \t");
237 name += strspn(name, " \t");
241 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
242 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
248 c->name = xstrdup(name);
250 // Send the node the contents of the invitation file
253 while((result = fread(buf, 1, sizeof buf, f)))
254 sptps_send_record(&c->sptps, 0, buf, result);
255 sptps_send_record(&c->sptps, 1, buf, 0);
259 c->status.invitation_used = true;
261 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
265 bool id_h(connection_t *c, const char *request) {
266 char name[MAX_STRING_SIZE];
268 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
269 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
274 /* Check if this is an invitation */
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);
350 read_ecdsa_public_key(c);
352 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
353 c->protocol_minor = 1;
356 /* Forbid version rollback for nodes whose ECDSA key we know */
358 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
359 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
360 c->name, c->hostname, c->protocol_major, c->protocol_minor);
364 c->allow_request = METAKEY;
366 if(c->protocol_minor >= 2) {
367 c->allow_request = ACK;
368 char label[25 + strlen(myself->name) + strlen(c->name)];
371 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
373 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
375 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
377 return send_metakey(c);
381 bool send_metakey(connection_t *c) {
382 if(!read_rsa_public_key(c))
385 if(!(c->outcipher = cipher_open_blowfish_ofb()))
388 if(!(c->outdigest = digest_open_sha1(-1)))
391 size_t len = rsa_size(c->rsa);
394 char hexkey[2 * len + 1];
396 /* Create a random key */
400 /* The message we send must be smaller than the modulus of the RSA key.
401 By definition, for a key of k bits, the following formula holds:
403 2^(k-1) <= modulus < 2^(k)
405 Where ^ means "to the power of", not "xor".
406 This means that to be sure, we must choose our message < 2^(k-1).
407 This can be done by setting the most significant bit to zero.
412 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
415 if(debug_level >= DEBUG_SCARY_THINGS) {
416 bin2hex(key, hexkey, len);
417 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
420 /* Encrypt the random data
422 We do not use one of the PKCS padding schemes here.
423 This is allowed, because we encrypt a totally random string
424 with a length equal to that of the modulus of the RSA key.
427 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
428 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
432 /* Convert the encrypted random data to a hexadecimal formatted string */
434 bin2hex(enckey, hexkey, len);
436 /* Send the meta key */
438 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
439 cipher_get_nid(c->outcipher),
440 digest_get_nid(c->outdigest), c->outmaclength,
441 c->outcompression, hexkey);
443 c->status.encryptout = true;
447 bool metakey_h(connection_t *c, const char *request) {
448 char hexkey[MAX_STRING_SIZE];
449 int cipher, digest, maclength, compression;
450 size_t len = rsa_size(myself->connection->rsa);
454 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
455 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
459 /* Convert the challenge from hexadecimal back to binary */
461 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
463 /* Check if the length of the meta key is all right */
466 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
470 /* Decrypt the meta key */
472 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
473 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
477 if(debug_level >= DEBUG_SCARY_THINGS) {
478 bin2hex(key, hexkey, len);
479 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
482 /* Check and lookup cipher and digest algorithms */
484 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
485 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
489 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
490 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
494 c->status.decryptin = true;
496 c->allow_request = CHALLENGE;
498 return send_challenge(c);
501 bool send_challenge(connection_t *c) {
502 size_t len = rsa_size(c->rsa);
503 char buffer[len * 2 + 1];
506 c->hischallenge = xrealloc(c->hischallenge, len);
508 /* Copy random data to the buffer */
510 randomize(c->hischallenge, len);
514 bin2hex(c->hischallenge, buffer, len);
516 /* Send the challenge */
518 return send_request(c, "%d %s", CHALLENGE, buffer);
521 bool challenge_h(connection_t *c, const char *request) {
522 char buffer[MAX_STRING_SIZE];
523 size_t len = rsa_size(myself->connection->rsa);
524 size_t digestlen = digest_length(c->indigest);
525 char digest[digestlen];
527 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
528 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
532 /* Convert the challenge from hexadecimal back to binary */
534 int inlen = hex2bin(buffer, buffer, sizeof buffer);
536 /* Check if the length of the challenge is all right */
539 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
543 /* Calculate the hash from the challenge we received */
545 if(!digest_create(c->indigest, buffer, len, digest))
548 /* Convert the hash to a hexadecimal formatted string */
550 bin2hex(digest, buffer, digestlen);
554 c->allow_request = CHAL_REPLY;
556 return send_request(c, "%d %s", CHAL_REPLY, buffer);
559 bool chal_reply_h(connection_t *c, const char *request) {
560 char hishash[MAX_STRING_SIZE];
562 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
563 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
568 /* Convert the hash to binary format */
570 int inlen = hex2bin(hishash, hishash, sizeof hishash);
572 /* Check if the length of the hash is all right */
574 if(inlen != digest_length(c->outdigest)) {
575 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
580 /* Verify the hash */
582 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
583 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
587 /* Identity has now been positively verified.
588 Send an acknowledgement with the rest of the information needed.
591 free(c->hischallenge);
592 c->hischallenge = NULL;
593 c->allow_request = ACK;
598 static bool send_upgrade(connection_t *c) {
599 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
600 * but doesn't know our key yet. So send it now. */
602 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
607 bool result = send_request(c, "%d %s", ACK, pubkey);
612 bool send_ack(connection_t *c) {
613 if(c->protocol_minor == 1)
614 return send_upgrade(c);
616 /* ACK message contains rest of the information the other end needs
617 to create node_t and edge_t structures. */
622 /* Estimate weight */
624 gettimeofday(&now, NULL);
625 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
627 /* Check some options */
629 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
630 c->options |= OPTION_INDIRECT;
632 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
633 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
635 if(myself->options & OPTION_PMTU_DISCOVERY)
636 c->options |= OPTION_PMTU_DISCOVERY;
638 choice = myself->options & OPTION_CLAMP_MSS;
639 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
641 c->options |= OPTION_CLAMP_MSS;
643 if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
644 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
646 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
649 static void send_everything(connection_t *c) {
650 /* Send all known subnets and edges */
653 if(disablebuggypeers) {
656 char pad[MAXBUFSIZE - MAXSIZE];
659 memset(&zeropkt, 0, sizeof zeropkt);
660 zeropkt.pkt.len = MAXBUFSIZE;
661 send_tcppacket(c, &zeropkt.pkt);
664 for splay_each(node_t, n, node_tree) {
665 for splay_each(edge_t, e, n->edge_tree)
670 static bool upgrade_h(connection_t *c, const char *request) {
671 char pubkey[MAX_STRING_SIZE];
673 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
674 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
678 if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
679 logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
683 logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
684 append_config_file(c->name, "ECDSAPublicKey", pubkey);
685 c->allow_request = TERMREQ;
686 return send_termreq(c);
689 bool ack_h(connection_t *c, const char *request) {
690 if(c->protocol_minor == 1)
691 return upgrade_h(c, request);
693 char hisport[MAX_STRING_SIZE];
700 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
701 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
706 /* Check if we already have a node_t for him */
708 n = lookup_node(c->name);
712 n->name = xstrdup(c->name);
716 /* Oh dear, we already have a connection to this node. */
717 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
719 if(n->connection->outgoing) {
721 logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
723 c->outgoing = n->connection->outgoing;
725 n->connection->outgoing = NULL;
728 terminate_connection(n->connection, false);
729 /* Run graph algorithm to keep things in sync */
736 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
737 c->options &= ~OPTION_PMTU_DISCOVERY;
738 options &= ~OPTION_PMTU_DISCOVERY;
740 c->options |= options;
742 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
745 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
748 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
750 c->options |= OPTION_CLAMP_MSS;
752 c->options &= ~OPTION_CLAMP_MSS;
755 /* Activate this connection */
757 c->allow_request = ALL;
758 c->status.active = true;
760 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
763 /* Send him everything we know */
767 /* Create an edge_t for this connection */
769 c->edge = new_edge();
770 c->edge->from = myself;
772 sockaddr2str(&c->address, &hisaddress, NULL);
773 c->edge->address = str2sockaddr(hisaddress, hisport);
775 c->edge->weight = (weight + c->estimated_weight) / 2;
776 c->edge->connection = c;
777 c->edge->options = c->options;
781 /* Notify everyone of the new edge */
783 send_add_edge(everyone, c->edge);
785 /* Run MST and SSSP algorithms */