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, "%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, 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, "%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_ecdsa_public_key(mesh, to)) {
84 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
85 send_request(mesh, to->nexthop->connection, "%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->self->connection->ecdsa, 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->self->connection->ecdsa);
111 send_request(mesh, from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
117 if(node_read_ecdsa_public_key(mesh, from)) {
118 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
122 char pubkey[MAX_STRING_SIZE];
124 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
125 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
129 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
130 append_config_file(mesh, from->name, "ECDSAPublicKey", pubkey);
135 if(!node_read_ecdsa_public_key(mesh, from)) {
136 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
137 send_request(mesh, from->nexthop->connection, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
141 if(from->sptps.label) {
142 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
144 if(strcmp(mesh->self->name, from->name) < 0) {
145 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
150 char buf[MAX_STRING_SIZE];
153 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
154 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
158 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
159 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
160 sptps_stop(&from->sptps);
161 from->status.validkey = false;
162 from->status.waitingforkey = true;
163 from->last_req_key = mesh->loop.now.tv_sec;
164 sptps_start(&from->sptps, from, false, true, mesh->self->connection->ecdsa, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record);
165 sptps_receive_data(&from->sptps, buf, len);
170 if(!from->status.validkey) {
171 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
175 char buf[MAX_STRING_SIZE];
178 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
179 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
183 sptps_receive_data(&from->sptps, buf, len);
188 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
193 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
194 char from_name[MAX_STRING_SIZE];
195 char to_name[MAX_STRING_SIZE];
199 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
200 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
204 if(!check_id(from_name) || !check_id(to_name)) {
205 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
209 from = lookup_node(mesh, from_name);
212 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
213 "REQ_KEY", c->name, from_name);
217 to = lookup_node(mesh, to_name);
220 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
221 "REQ_KEY", c->name, to_name);
225 /* Check if this key request is for us */
227 if(to == mesh->self) { /* Yes */
228 /* Is this an extended REQ_KEY message? */
230 return req_key_ext_h(mesh, c, request, from, reqno);
233 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
234 return from->connection != c;
236 if(!to->status.reachable) {
237 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
238 "REQ_KEY", c->name, to_name);
242 send_request(mesh, to->nexthop->connection, "%s", request);
248 bool send_ans_key(meshlink_handle_t *mesh, node_t *to) {
254 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
255 char from_name[MAX_STRING_SIZE];
256 char to_name[MAX_STRING_SIZE];
257 char key[MAX_STRING_SIZE];
258 char address[MAX_STRING_SIZE] = "";
259 char port[MAX_STRING_SIZE] = "";
260 int cipher, digest, maclength, compression;
263 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
264 from_name, to_name, key, &cipher, &digest, &maclength,
265 &compression, address, port) < 7) {
266 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
270 if(!check_id(from_name) || !check_id(to_name)) {
271 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
275 from = lookup_node(mesh, from_name);
278 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
279 "ANS_KEY", c->name, from_name);
283 to = lookup_node(mesh, to_name);
286 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
287 "ANS_KEY", c->name, to_name);
291 /* Forward it if necessary */
293 if(to != mesh->self) {
294 if(!to->status.reachable) {
295 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
296 "ANS_KEY", c->name, to_name);
300 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
301 char *address, *port;
302 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
303 sockaddr2str(&from->address, &address, &port);
304 send_request(mesh, to->nexthop->connection, "%s %s %s", request, address, port);
310 return send_request(mesh, to->nexthop->connection, "%s", request);
313 /* Don't use key material until every check has passed. */
314 from->status.validkey = false;
316 /* Compression is not supported. */
317 if(compression != 0) {
318 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
322 from->outcompression = compression;
324 /* SPTPS or old-style key exchange? */
326 char buf[strlen(key)];
327 int len = b64decode(key, buf, strlen(key));
329 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
330 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
333 if(from->status.validkey) {
334 if(*address && *port) {
335 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
336 sockaddr_t sa = str2sockaddr(address, port);
337 update_node_udp(mesh, from, &sa);
340 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY)) {
341 send_mtu_probe(mesh, from);