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"
44 ecdsa_t *invitation_key = NULL;
46 static bool send_proxyrequest(connection_t *c) {
52 sockaddr2str(&c->address, &host, &port);
53 send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
59 if(c->address.sa.sa_family != AF_INET) {
60 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
63 char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
66 memcpy(s4req + 2, &c->address.in.sin_port, 2);
67 memcpy(s4req + 4, &c->address.in.sin_addr, 4);
69 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
70 s4req[sizeof s4req - 1] = 0;
72 return send_meta(c, s4req, sizeof s4req);
75 int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
78 len += 3 + strlen(proxyuser) + strlen(proxypass);
86 s5req[i++] = strlen(proxyuser);
87 memcpy(s5req + i, proxyuser, strlen(proxyuser));
88 i += strlen(proxyuser);
89 s5req[i++] = strlen(proxypass);
90 memcpy(s5req + i, proxypass, strlen(proxypass));
91 i += strlen(proxypass);
99 if(c->address.sa.sa_family == AF_INET) {
101 memcpy(s5req + i, &c->address.in.sin_addr, 4);
103 memcpy(s5req + i, &c->address.in.sin_port, 2);
106 } else if(c->address.sa.sa_family == AF_INET6) {
108 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
110 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
114 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
119 return send_meta(c, s5req, sizeof s5req);
122 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
127 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
132 bool send_id(connection_t *c) {
133 gettimeofday(&c->start, NULL);
138 if(c->outgoing && !read_ecdsa_public_key(c))
141 minor = myself->connection->protocol_minor;
144 if(proxytype && c->outgoing)
145 if(!send_proxyrequest(c))
148 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
151 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
152 if(strchr(data, '\n')) {
153 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
157 // Create a new host config file
158 char filename[PATH_MAX];
159 snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
160 if(!access(filename, F_OK)) {
161 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
165 FILE *f = fopen(filename, "w");
167 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
171 fprintf(f, "ECDSAPublicKey = %s\n", data);
174 logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
176 //TODO: callback to application to inform of an accepted invitation
178 sptps_send_record(&c->sptps, 2, data, 0);
182 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
183 connection_t *c = handle;
188 if(type == 1 && c->status.invitation_used)
189 return finalize_invitation(c, data, len);
191 if(type != 0 || len != 18 || c->status.invitation_used)
194 // Recover the filename from the cookie and the key
195 digest_t *digest = digest_open_by_name("sha256", 18);
198 char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
199 char hashbuf[18 + strlen(fingerprint)];
201 memcpy(hashbuf, data, 18);
202 memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
203 digest_create(digest, hashbuf, sizeof hashbuf, cookie);
204 b64encode_urlsafe(cookie, cookie, 18);
205 digest_close(digest);
208 char filename[PATH_MAX], usedname[PATH_MAX];
209 snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
210 snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
212 // Atomically rename the invitation file
213 if(rename(filename, usedname)) {
215 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
217 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
221 // Open the renamed file
222 FILE *f = fopen(usedname, "r");
224 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
228 // Read the new node's Name from the file
230 fgets(buf, sizeof buf, f);
232 buf[strlen(buf) - 1] = 0;
234 len = strcspn(buf, " \t=");
235 char *name = buf + len;
236 name += strspn(name, " \t");
239 name += strspn(name, " \t");
243 if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
244 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
250 c->name = xstrdup(name);
252 // Send the node the contents of the invitation file
255 while((result = fread(buf, 1, sizeof buf, f)))
256 sptps_send_record(&c->sptps, 0, buf, result);
257 sptps_send_record(&c->sptps, 1, buf, 0);
261 c->status.invitation_used = true;
263 logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
267 bool id_h(connection_t *c, const char *request) {
268 char name[MAX_STRING_SIZE];
270 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
271 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
276 /* Check if this is an invitation */
279 if(!invitation_key) {
280 logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
284 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
286 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
290 c->status.invitation = true;
291 char *mykey = ecdsa_get_base64_public_key(invitation_key);
294 if(!send_request(c, "%d %s", ACK, mykey))
298 c->protocol_minor = 2;
300 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
303 /* Check if identity is a valid name */
305 if(!check_id(name)) {
306 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
307 c->hostname, "invalid name");
311 /* If this is an outgoing connection, make sure we are connected to the right host */
314 if(strcmp(c->name, name)) {
315 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
322 c->name = xstrdup(name);
325 /* Check if version matches */
327 if(c->protocol_major != myself->connection->protocol_major) {
328 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
329 c->name, c->hostname, c->protocol_major, c->protocol_minor);
333 if(bypass_security) {
335 init_configuration(&c->config_tree);
336 c->allow_request = ACK;
341 c->protocol_minor = 0;
343 if(!c->config_tree) {
344 init_configuration(&c->config_tree);
346 if(!read_host_config(c->config_tree, c->name)) {
347 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
352 read_ecdsa_public_key(c);
354 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
355 c->protocol_minor = 1;
358 /* Forbid version rollback for nodes whose ECDSA key we know */
360 if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
361 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
362 c->name, c->hostname, c->protocol_major, c->protocol_minor);
366 c->allow_request = METAKEY;
368 if(c->protocol_minor >= 2) {
369 c->allow_request = ACK;
370 char label[25 + strlen(myself->name) + strlen(c->name)];
373 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
375 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
377 return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
379 return send_metakey(c);
383 bool send_metakey(connection_t *c) {
384 if(!read_rsa_public_key(c))
387 if(!(c->outcipher = cipher_open_blowfish_ofb()))
390 if(!(c->outdigest = digest_open_sha1(-1)))
393 size_t len = rsa_size(c->rsa);
396 char hexkey[2 * len + 1];
398 /* Create a random key */
402 /* The message we send must be smaller than the modulus of the RSA key.
403 By definition, for a key of k bits, the following formula holds:
405 2^(k-1) <= modulus < 2^(k)
407 Where ^ means "to the power of", not "xor".
408 This means that to be sure, we must choose our message < 2^(k-1).
409 This can be done by setting the most significant bit to zero.
414 if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
417 if(debug_level >= DEBUG_SCARY_THINGS) {
418 bin2hex(key, hexkey, len);
419 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
422 /* Encrypt the random data
424 We do not use one of the PKCS padding schemes here.
425 This is allowed, because we encrypt a totally random string
426 with a length equal to that of the modulus of the RSA key.
429 if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
430 logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
434 /* Convert the encrypted random data to a hexadecimal formatted string */
436 bin2hex(enckey, hexkey, len);
438 /* Send the meta key */
440 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
441 cipher_get_nid(c->outcipher),
442 digest_get_nid(c->outdigest), c->outmaclength,
443 c->outcompression, hexkey);
445 c->status.encryptout = true;
449 bool metakey_h(connection_t *c, const char *request) {
450 char hexkey[MAX_STRING_SIZE];
451 int cipher, digest, maclength, compression;
452 size_t len = rsa_size(myself->connection->rsa);
456 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
457 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
461 /* Convert the challenge from hexadecimal back to binary */
463 int inlen = hex2bin(hexkey, enckey, sizeof enckey);
465 /* Check if the length of the meta key is all right */
468 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
472 /* Decrypt the meta key */
474 if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
475 logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
479 if(debug_level >= DEBUG_SCARY_THINGS) {
480 bin2hex(key, hexkey, len);
481 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
484 /* Check and lookup cipher and digest algorithms */
486 if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
487 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
491 if(!(c->indigest = digest_open_by_nid(digest, -1))) {
492 logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
496 c->status.decryptin = true;
498 c->allow_request = CHALLENGE;
500 return send_challenge(c);
503 bool send_challenge(connection_t *c) {
504 size_t len = rsa_size(c->rsa);
505 char buffer[len * 2 + 1];
508 c->hischallenge = xrealloc(c->hischallenge, len);
510 /* Copy random data to the buffer */
512 randomize(c->hischallenge, len);
516 bin2hex(c->hischallenge, buffer, len);
518 /* Send the challenge */
520 return send_request(c, "%d %s", CHALLENGE, buffer);
523 bool challenge_h(connection_t *c, const char *request) {
524 char buffer[MAX_STRING_SIZE];
525 size_t len = rsa_size(myself->connection->rsa);
526 size_t digestlen = digest_length(c->indigest);
527 char digest[digestlen];
529 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
530 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
534 /* Convert the challenge from hexadecimal back to binary */
536 int inlen = hex2bin(buffer, buffer, sizeof buffer);
538 /* Check if the length of the challenge is all right */
541 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
545 /* Calculate the hash from the challenge we received */
547 if(!digest_create(c->indigest, buffer, len, digest))
550 /* Convert the hash to a hexadecimal formatted string */
552 bin2hex(digest, buffer, digestlen);
556 c->allow_request = CHAL_REPLY;
558 return send_request(c, "%d %s", CHAL_REPLY, buffer);
561 bool chal_reply_h(connection_t *c, const char *request) {
562 char hishash[MAX_STRING_SIZE];
564 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
565 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
570 /* Convert the hash to binary format */
572 int inlen = hex2bin(hishash, hishash, sizeof hishash);
574 /* Check if the length of the hash is all right */
576 if(inlen != digest_length(c->outdigest)) {
577 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
582 /* Verify the hash */
584 if(!digest_verify(c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
585 logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
589 /* Identity has now been positively verified.
590 Send an acknowledgement with the rest of the information needed.
593 free(c->hischallenge);
594 c->hischallenge = NULL;
595 c->allow_request = ACK;
600 static bool send_upgrade(connection_t *c) {
601 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
602 * but doesn't know our key yet. So send it now. */
604 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
609 bool result = send_request(c, "%d %s", ACK, pubkey);
614 bool send_ack(connection_t *c) {
615 if(c->protocol_minor == 1)
616 return send_upgrade(c);
618 /* ACK message contains rest of the information the other end needs
619 to create node_t and edge_t structures. */
624 /* Estimate weight */
626 gettimeofday(&now, NULL);
627 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
629 /* Check some options */
631 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
632 c->options |= OPTION_INDIRECT;
634 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
635 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
637 if(myself->options & OPTION_PMTU_DISCOVERY)
638 c->options |= OPTION_PMTU_DISCOVERY;
640 choice = myself->options & OPTION_CLAMP_MSS;
641 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
643 c->options |= OPTION_CLAMP_MSS;
645 if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
646 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
648 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
651 static void send_everything(connection_t *c) {
652 /* Send all known subnets and edges */
655 if(disablebuggypeers) {
658 char pad[MAXBUFSIZE - MAXSIZE];
661 memset(&zeropkt, 0, sizeof zeropkt);
662 zeropkt.pkt.len = MAXBUFSIZE;
663 send_tcppacket(c, &zeropkt.pkt);
666 for splay_each(node_t, n, node_tree) {
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 keep things in sync */
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 */