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 void send_key_changed(meshlink_handle_t *mesh) {
35 send_request(mesh, mesh->everyone, NULL, "%d %x %s", KEY_CHANGED, rand(), mesh->self->name);
37 /* Force key exchange for connections using SPTPS */
39 for splay_each(node_t, n, mesh->nodes)
40 if(n->status.reachable && n->status.validkey) {
41 sptps_force_kex(&n->sptps);
45 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
46 char name[MAX_STRING_SIZE];
49 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
50 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
54 if(seen_request(mesh, request)) {
58 n = lookup_node(mesh, name);
61 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
67 forward_request(mesh, c, NULL, request);
72 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
75 meshlink_handle_t *mesh = to->mesh;
76 to->sptps.send_data = send_sptps_data;
77 char buf[len * 4 / 3 + 5];
78 b64encode(data, buf, len);
79 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
82 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
83 if(!node_read_public_key(mesh, to)) {
84 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
85 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
90 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
93 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
94 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
95 sptps_stop(&to->sptps);
96 to->status.validkey = false;
97 to->status.waitingforkey = true;
98 to->last_req_key = mesh->loop.now.tv_sec;
99 to->incompression = mesh->self->incompression;
100 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
103 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
105 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
110 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
112 if(!from->nexthop || !from->nexthop->connection) {
116 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
122 if(node_read_public_key(mesh, from)) {
123 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
127 char pubkey[MAX_STRING_SIZE];
129 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
130 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
134 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
135 from->status.dirty = true;
140 if(!node_read_public_key(mesh, from)) {
141 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
142 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
146 if(from->sptps.label) {
147 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
149 if(strcmp(mesh->self->name, from->name) < 0) {
150 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
155 char buf[MAX_STRING_SIZE];
158 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
159 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
163 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
164 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
165 sptps_stop(&from->sptps);
166 from->status.validkey = false;
167 from->status.waitingforkey = true;
168 from->last_req_key = mesh->loop.now.tv_sec;
169 sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record);
170 sptps_receive_data(&from->sptps, buf, len);
175 if(!from->status.validkey) {
176 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
180 char buf[MAX_STRING_SIZE];
183 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
184 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
188 sptps_receive_data(&from->sptps, buf, len);
193 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
198 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
199 char from_name[MAX_STRING_SIZE];
200 char to_name[MAX_STRING_SIZE];
204 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
205 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
209 if(!check_id(from_name) || !check_id(to_name)) {
210 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
214 from = lookup_node(mesh, from_name);
217 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
218 "REQ_KEY", c->name, from_name);
222 to = lookup_node(mesh, to_name);
225 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
226 "REQ_KEY", c->name, to_name);
230 /* Check if this key request is for us */
232 if(to == mesh->self) { /* Yes */
233 /* Is this an extended REQ_KEY message? */
235 return req_key_ext_h(mesh, c, request, from, reqno);
238 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
239 return from->connection != c;
241 if(!to->status.reachable) {
242 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
243 "REQ_KEY", c->name, to_name);
247 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
253 bool send_ans_key(meshlink_handle_t *mesh, node_t *to) {
259 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
260 char from_name[MAX_STRING_SIZE];
261 char to_name[MAX_STRING_SIZE];
262 char key[MAX_STRING_SIZE];
263 char address[MAX_STRING_SIZE] = "";
264 char port[MAX_STRING_SIZE] = "";
265 int cipher, digest, maclength, compression;
268 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
269 from_name, to_name, key, &cipher, &digest, &maclength,
270 &compression, address, port) < 7) {
271 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
275 if(!check_id(from_name) || !check_id(to_name)) {
276 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
280 from = lookup_node(mesh, from_name);
283 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
284 "ANS_KEY", c->name, from_name);
288 to = lookup_node(mesh, to_name);
291 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
292 "ANS_KEY", c->name, to_name);
296 /* Forward it if necessary */
298 if(to != mesh->self) {
299 if(!to->status.reachable) {
300 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
301 "ANS_KEY", c->name, to_name);
305 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
306 char *address, *port;
307 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
308 sockaddr2str(&from->address, &address, &port);
309 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, address, port);
315 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
318 /* Don't use key material until every check has passed. */
319 from->status.validkey = false;
321 /* Compression is not supported. */
322 if(compression != 0) {
323 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
327 from->outcompression = compression;
329 /* SPTPS or old-style key exchange? */
331 char buf[strlen(key)];
332 int len = b64decode(key, buf, strlen(key));
334 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
335 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
338 if(from->status.validkey) {
339 if(*address && *port) {
340 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
341 sockaddr_t sa = str2sockaddr(address, port);
342 update_node_udp(mesh, from, &sa);
345 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY)) {
346 send_mtu_probe(mesh, from);