2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 2014-2017 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.
22 #include "connection.h"
24 #include "meshlink_internal.h"
34 static const int req_key_timeout = 2;
36 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
40 char name[MAX_STRING_SIZE];
43 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
44 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
48 n = lookup_node(mesh, name);
51 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
58 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
65 meshlink_handle_t *mesh = to->mesh;
67 if(!to->nexthop || !to->nexthop->connection) {
68 logger(mesh, MESHLINK_WARNING, "Cannot send SPTPS data to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
72 to->sptps.send_data = send_sptps_data;
73 char buf[len * 4 / 3 + 5];
74 b64encode(data, buf, len);
75 return send_request(mesh, to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
78 bool send_canonical_address(meshlink_handle_t *mesh, node_t *to) {
79 if(!mesh->self->canonical_address) {
83 return send_request(mesh, to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_CANONICAL, mesh->self->canonical_address);
86 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
87 if(!node_read_public_key(mesh, to)) {
88 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
90 if(!to->nexthop || !to->nexthop->connection) {
91 logger(mesh, MESHLINK_WARNING, "Cannot send REQ_PUBKEY to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
95 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
96 send_request(mesh, to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY, pubkey);
101 if(to->sptps.label) {
102 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
105 /* Send our canonical address to help with UDP hole punching */
106 send_canonical_address(mesh, to);
108 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
109 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
110 sptps_stop(&to->sptps);
111 to->status.validkey = false;
112 to->status.waitingforkey = true;
113 to->last_req_key = mesh->loop.now.tv_sec;
114 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
117 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
119 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
122 if(!from->nexthop || !from->nexthop->connection) {
123 logger(mesh, MESHLINK_WARNING, "Cannot answer REQ_KEY from %s via %s", from->name, from->nexthop ? from->nexthop->name : from->name);
129 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
131 if(!node_read_public_key(mesh, from)) {
132 char hiskey[MAX_STRING_SIZE];
134 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, hiskey) == 1) {
135 from->ecdsa = ecdsa_set_base64_public_key(hiskey);
138 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_PUBKEY", from->name, "invalid pubkey");
142 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
143 from->status.dirty = true;
145 if(!node_write_config(mesh, from, true)) {
151 send_request(mesh, from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
157 if(node_read_public_key(mesh, from)) {
158 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
162 char pubkey[MAX_STRING_SIZE];
164 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
165 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
169 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
170 from->status.dirty = true;
172 if(!node_write_config(mesh, from, true)) {
176 /* If we are trying to form an outgoing connection to this node, retry immediately */
178 if(mesh->outgoing->node == from && mesh->outgoing->ev.cb) {
179 mesh->outgoing->timeout = 0;
180 timeout_set(&mesh->loop, &mesh->outgoing->ev, &(struct timespec) {
186 /* Also reset any UTCP timers */
187 utcp_reset_timers(from->utcp);
193 if(!node_read_public_key(mesh, from)) {
194 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
195 send_request(mesh, from->nexthop->connection, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
199 if(from->sptps.label) {
200 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
202 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
203 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
208 char buf[MAX_STRING_SIZE];
211 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
212 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
216 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
217 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
218 sptps_stop(&from->sptps);
219 from->status.validkey = false;
220 from->status.waitingforkey = true;
221 from->last_req_key = mesh->loop.now.tv_sec;
223 /* Send our canonical address to help with UDP hole punching */
224 send_canonical_address(mesh, from);
226 if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
227 logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
231 if(!sptps_receive_data(&from->sptps, buf, len)) {
232 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
240 if(!from->status.validkey) {
241 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
245 char buf[MAX_STRING_SIZE];
248 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
249 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
253 if(!sptps_receive_data(&from->sptps, buf, len)) {
254 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
261 case REQ_CANONICAL: {
262 char host[MAX_STRING_SIZE];
263 char port[MAX_STRING_SIZE];
265 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING " " MAX_STRING, host, port) != 2) {
266 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_CANONICAL", from->name, "invalid canonical address");
270 char *canonical_address;
271 xasprintf(&canonical_address, "%s %s", host, port);
273 if(mesh->log_level <= MESHLINK_DEBUG && (!from->canonical_address || strcmp(from->canonical_address, canonical_address))) {
274 logger(mesh, MESHLINK_DEBUG, "Updating canonical address of %s to %s", from->name, canonical_address);
277 free(from->canonical_address);
278 from->canonical_address = canonical_address;
283 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
288 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
292 char from_name[MAX_STRING_SIZE];
293 char to_name[MAX_STRING_SIZE];
297 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
298 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
302 if(!check_id(from_name) || !check_id(to_name)) {
303 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
307 from = lookup_node(mesh, from_name);
310 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
311 "REQ_KEY", c->name, from_name);
315 to = lookup_node(mesh, to_name);
318 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
319 "REQ_KEY", c->name, to_name);
323 /* Check if this key request is for us */
325 if(to == mesh->self) { /* Yes */
326 /* Is this an extended REQ_KEY message? */
328 return req_key_ext_h(mesh, c, request, from, reqno);
331 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
332 return from->connection != c;
334 if(!to->status.reachable || !to->nexthop || !to->nexthop->connection) {
335 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
336 "REQ_KEY", c->name, to_name);
340 send_request(mesh, to->nexthop->connection, "%s", request);
346 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
350 char from_name[MAX_STRING_SIZE];
351 char to_name[MAX_STRING_SIZE];
352 char key[MAX_STRING_SIZE];
353 char address[MAX_STRING_SIZE] = "";
354 char port[MAX_STRING_SIZE] = "";
355 int cipher, digest, maclength, compression;
358 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
359 from_name, to_name, key, &cipher, &digest, &maclength,
360 &compression, address, port) < 7) {
361 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
365 if(!check_id(from_name) || !check_id(to_name)) {
366 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
370 from = lookup_node(mesh, from_name);
373 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
374 "ANS_KEY", c->name, from_name);
378 to = lookup_node(mesh, to_name);
381 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
382 "ANS_KEY", c->name, to_name);
386 /* Forward it if necessary */
388 if(to != mesh->self) {
389 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not for us",
390 "ANS_KEY", c->name, to_name);
394 /* Is this an ANS_KEY informing us of our own reflexive UDP address? */
396 if(from == mesh->self) {
397 if(*key == '.' && *address && *port) {
398 /* Ignore reflexive UDP address */
400 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
401 "ANS_KEY", c->name, from_name, to_name);
407 /* Process SPTPS data if present */
410 /* Don't use key material until every check has passed. */
411 from->status.validkey = false;
413 /* Compression is not supported. */
414 if(compression != 0) {
415 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
419 char buf[strlen(key)];
420 int len = b64decode(key, buf, strlen(key));
422 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
423 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
427 if(from->status.validkey) {
428 if(*address && *port) {
429 /* Ignore reflexive UDP address */