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 void send_key_changed(meshlink_handle_t *mesh) {
37 send_request(mesh, mesh->everyone, NULL, "%d %x %s", KEY_CHANGED, prng(mesh, UINT_MAX), mesh->self->name);
39 /* Force key exchange for connections using SPTPS */
41 for splay_each(node_t, n, mesh->nodes)
42 if(n->status.reachable && n->status.validkey) {
43 sptps_force_kex(&n->sptps);
47 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
51 char name[MAX_STRING_SIZE];
54 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
55 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
59 if(seen_request(mesh, request)) {
63 n = lookup_node(mesh, name);
66 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
72 forward_request(mesh, c, NULL, request);
77 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
84 meshlink_handle_t *mesh = to->mesh;
85 to->sptps.send_data = send_sptps_data;
86 char buf[len * 4 / 3 + 5];
87 b64encode(data, buf, len);
88 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
91 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
92 if(!node_read_public_key(mesh, to)) {
93 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
94 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
99 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
102 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
103 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
104 sptps_stop(&to->sptps);
105 to->status.validkey = false;
106 to->status.waitingforkey = true;
107 to->last_req_key = mesh->loop.now.tv_sec;
108 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
111 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
113 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
118 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
120 if(!from->nexthop || !from->nexthop->connection) {
124 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
130 if(node_read_public_key(mesh, from)) {
131 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
135 char pubkey[MAX_STRING_SIZE];
137 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
138 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_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 we are trying to form an outgoing connection to this node, retry immediately */
146 for list_each(outgoing_t, outgoing, mesh->outgoings) {
147 if(outgoing->node == from && outgoing->ev.cb) {
148 outgoing->timeout = 0;
149 timeout_set(&mesh->loop, &outgoing->ev, &(struct timeval) {
155 /* Also reset any UTCP timers */
156 utcp_reset_timers(from->utcp);
162 if(!node_read_public_key(mesh, from)) {
163 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
164 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
168 if(from->sptps.label) {
169 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
171 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
172 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
177 char buf[MAX_STRING_SIZE];
180 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
181 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
185 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
186 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
187 sptps_stop(&from->sptps);
188 from->status.validkey = false;
189 from->status.waitingforkey = true;
190 from->last_req_key = mesh->loop.now.tv_sec;
191 sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record);
192 sptps_receive_data(&from->sptps, buf, len);
197 if(!from->status.validkey) {
198 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
202 char buf[MAX_STRING_SIZE];
205 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
206 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
210 sptps_receive_data(&from->sptps, buf, len);
215 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
220 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
224 char from_name[MAX_STRING_SIZE];
225 char to_name[MAX_STRING_SIZE];
229 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
230 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
234 if(!check_id(from_name) || !check_id(to_name)) {
235 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
239 from = lookup_node(mesh, from_name);
242 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
243 "REQ_KEY", c->name, from_name);
247 to = lookup_node(mesh, to_name);
250 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
251 "REQ_KEY", c->name, to_name);
255 /* Check if this key request is for us */
257 if(to == mesh->self) { /* Yes */
258 /* Is this an extended REQ_KEY message? */
260 return req_key_ext_h(mesh, c, request, from, reqno);
263 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
264 return from->connection != c;
266 if(!to->status.reachable) {
267 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
268 "REQ_KEY", c->name, to_name);
272 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
278 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
282 char from_name[MAX_STRING_SIZE];
283 char to_name[MAX_STRING_SIZE];
284 char key[MAX_STRING_SIZE];
285 char address[MAX_STRING_SIZE] = "";
286 char port[MAX_STRING_SIZE] = "";
287 int cipher, digest, maclength, compression;
290 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
291 from_name, to_name, key, &cipher, &digest, &maclength,
292 &compression, address, port) < 7) {
293 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
297 if(!check_id(from_name) || !check_id(to_name)) {
298 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
302 from = lookup_node(mesh, from_name);
305 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
306 "ANS_KEY", c->name, from_name);
310 to = lookup_node(mesh, to_name);
313 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
314 "ANS_KEY", c->name, to_name);
318 /* Forward it if necessary */
320 if(to != mesh->self) {
321 if(!to->status.reachable) {
322 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
323 "ANS_KEY", c->name, to_name);
327 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
328 char *address, *port;
329 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
330 sockaddr2str(&from->address, &address, &port);
331 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, address, port);
337 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
340 /* Don't use key material until every check has passed. */
341 from->status.validkey = false;
343 /* Compression is not supported. */
344 if(compression != 0) {
345 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
349 /* SPTPS or old-style key exchange? */
351 char buf[strlen(key)];
352 int len = b64decode(key, buf, strlen(key));
354 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
355 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
358 if(from->status.validkey) {
359 if(*address && *port) {
360 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
361 sockaddr_t sa = str2sockaddr(address, port);
362 update_node_udp(mesh, from, &sa);
365 send_mtu_probe(mesh, from);