git.meshlink.io Git - meshlink/blob - src/protocol_auth.c

   1 /*
   2     protocol_auth.c -- handle the meta-protocol, authentication
   3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
   4
   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.
   9
  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.
  14
  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.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "conf.h"
  23 #include "connection.h"
  24 #include "ecdsa.h"
  25 #include "edge.h"
  26 #include "graph.h"
  27 #include "logger.h"
  28 #include "meshlink_internal.h"
  29 #include "meta.h"
  30 #include "net.h"
  31 #include "netutl.h"
  32 #include "node.h"
  33 #include "prf.h"
  34 #include "protocol.h"
  35 #include "sptps.h"
  36 #include "utils.h"
  37 #include "xalloc.h"
  38 #include "ed25519/sha512.h"
  39
  40 static bool send_proxyrequest(meshlink_handle_t *mesh, connection_t *c) {
  41         switch(mesh->proxytype) {
  42                 case PROXY_HTTP: {
  43                         char *host;
  44                         char *port;
  45
  46                         sockaddr2str(&c->address, &host, &port);
  47                         send_request(mesh, c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
  48                         free(host);
  49                         free(port);
  50                         return true;
  51                 }
  52                 case PROXY_SOCKS4: {
  53                         if(c->address.sa.sa_family != AF_INET) {
  54                                 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
  55                                 return false;
  56                         }
  57                         char s4req[9 + (mesh->proxyuser ? strlen(mesh->proxyuser) : 0)];
  58                         s4req[0] = 4;
  59                         s4req[1] = 1;
  60                         memcpy(s4req + 2, &c->address.in.sin_port, 2);
  61                         memcpy(s4req + 4, &c->address.in.sin_addr, 4);
  62                         if(mesh->proxyuser)
  63                                 memcpy(s4req + 8, mesh->proxyuser, strlen(mesh->proxyuser));
  64                         s4req[sizeof s4req - 1] = 0;
  65                         c->tcplen = 8;
  66                         return send_meta(mesh, c, s4req, sizeof s4req);
  67                 }
  68                 case PROXY_SOCKS5: {
  69                         int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
  70                         c->tcplen = 2;
  71                         if(mesh->proxypass)
  72                                 len += 3 + strlen(mesh->proxyuser) + strlen(mesh->proxypass);
  73                         char s5req[len];
  74                         int i = 0;
  75                         s5req[i++] = 5;
  76                         s5req[i++] = 1;
  77                         if(mesh->proxypass) {
  78                                 s5req[i++] = 2;
  79                                 s5req[i++] = 1;
  80                                 s5req[i++] = strlen(mesh->proxyuser);
  81                                 memcpy(s5req + i, mesh->proxyuser, strlen(mesh->proxyuser));
  82                                 i += strlen(mesh->proxyuser);
  83                                 s5req[i++] = strlen(mesh->proxypass);
  84                                 memcpy(s5req + i, mesh->proxypass, strlen(mesh->proxypass));
  85                                 i += strlen(mesh->proxypass);
  86                                 c->tcplen += 2;
  87                         } else {
  88                                 s5req[i++] = 0;
  89                         }
  90                         s5req[i++] = 5;
  91                         s5req[i++] = 1;
  92                         s5req[i++] = 0;
  93                         if(c->address.sa.sa_family == AF_INET) {
  94                                 s5req[i++] = 1;
  95                                 memcpy(s5req + i, &c->address.in.sin_addr, 4);
  96                                 i += 4;
  97                                 memcpy(s5req + i, &c->address.in.sin_port, 2);
  98                                 i += 2;
  99                                 c->tcplen += 10;
 100                         } else if(c->address.sa.sa_family == AF_INET6) {
 101                                 s5req[i++] = 3;
 102                                 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
 103                                 i += 16;
 104                                 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
 105                                 i += 2;
 106                                 c->tcplen += 22;
 107                         } else {
 108                                 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
 109                                 return false;
 110                         }
 111                         if(i > len)
 112                                 abort();
 113                         return send_meta(mesh, c, s5req, sizeof s5req);
 114                 }
 115                 case PROXY_SOCKS4A:
 116                         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
 117                         return false;
 118                 case PROXY_EXEC:
 119                         return true;
 120                 default:
 121                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
 122                         return false;
 123         }
 124 }
 125
 126 bool send_id(meshlink_handle_t *mesh, connection_t *c) {
 127         gettimeofday(&c->start, NULL);
 128
 129         int minor = mesh->self->connection->protocol_minor;
 130
 131         if(mesh->proxytype && c->outgoing)
 132                 if(!send_proxyrequest(mesh, c))
 133                         return false;
 134
 135         return send_request(mesh, c, "%d %s %d.%d", ID, mesh->self->connection->name, mesh->self->connection->protocol_major, minor);
 136 }
 137
 138 static bool finalize_invitation(meshlink_handle_t *mesh, connection_t *c, const char *data, uint16_t len) {
 139         if(strchr(data, '\n')) {
 140                 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
 141                 return false;
 142         }
 143
 144         // Create a new host config file
 145         char filename[PATH_MAX];
 146         snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", mesh->confbase, c->name);
 147         if(!access(filename, F_OK)) {
 148                 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
 149                 return false;
 150         }
 151
 152         FILE *f = fopen(filename, "w");
 153         if(!f) {
 154                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
 155                 return false;
 156         }
 157
 158         fprintf(f, "ECDSAPublicKey = %s\n", data);
 159         fclose(f);
 160
 161         logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
 162
 163         //TODO: callback to application to inform of an accepted invitation
 164
 165         sptps_send_record(&c->sptps, 2, data, 0);
 166         return true;
 167 }
 168
 169 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
 170         connection_t *c = handle;
 171         meshlink_handle_t *mesh = c->mesh;
 172
 173         if(type == 128)
 174                 return true;
 175
 176         if(type == 1 && c->status.invitation_used)
 177                 return finalize_invitation(mesh, c, data, len);
 178
 179         if(type != 0 || len != 18 || c->status.invitation_used)
 180                 return false;
 181
 182         // Recover the filename from the cookie and the key
 183         char *fingerprint = ecdsa_get_base64_public_key(mesh->invitation_key);
 184         char hash[64];
 185         char hashbuf[18 + strlen(fingerprint)];
 186         char cookie[25];
 187         memcpy(hashbuf, data, 18);
 188         memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
 189         sha512(hashbuf, sizeof hashbuf, hash);
 190         b64encode_urlsafe(hash, cookie, 18);
 191         free(fingerprint);
 192
 193         char filename[PATH_MAX], usedname[PATH_MAX];
 194         snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookie);
 195         snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, cookie);
 196
 197         // Atomically rename the invitation file
 198         if(rename(filename, usedname)) {
 199                 if(errno == ENOENT)
 200                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
 201                 else
 202                         logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
 203                 return false;
 204         }
 205
 206         // Open the renamed file
 207         FILE *f = fopen(usedname, "r");
 208         if(!f) {
 209                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 210                 return false;
 211         }
 212
 213         // Read the new node's Name from the file
 214         char buf[1024];
 215         fgets(buf, sizeof buf, f);
 216         if(*buf)
 217                 buf[strlen(buf) - 1] = 0;
 218
 219         len = strcspn(buf, " \t=");
 220         char *name = buf + len;
 221         name += strspn(name, " \t");
 222         if(*name == '=') {
 223                 name++;
 224                 name += strspn(name, " \t");
 225         }
 226         buf[len] = 0;
 227
 228         if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
 229                 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
 230                 fclose(f);
 231                 return false;
 232         }
 233
 234         free(c->name);
 235         c->name = xstrdup(name);
 236
 237         // Send the node the contents of the invitation file
 238         rewind(f);
 239         size_t result;
 240         while((result = fread(buf, 1, sizeof buf, f)))
 241                 sptps_send_record(&c->sptps, 0, buf, result);
 242         sptps_send_record(&c->sptps, 1, buf, 0);
 243         fclose(f);
 244         unlink(usedname);
 245
 246         c->status.invitation_used = true;
 247
 248         logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
 249         return true;
 250 }
 251
 252 bool id_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 253         char name[MAX_STRING_SIZE];
 254
 255         if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 256                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 257                            c->hostname);
 258                 return false;
 259         }
 260
 261         /* Check if this is an invitation  */
 262
 263         if(name[0] == '?') {
 264                 if(!mesh->invitation_key) {
 265                         logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 266                         return false;
 267                 }
 268
 269                 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
 270                 if(!c->ecdsa) {
 271                         logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 272                         return false;
 273                 }
 274
 275                 c->status.invitation = true;
 276                 char *mykey = ecdsa_get_base64_public_key(mesh->invitation_key);
 277                 if(!mykey)
 278                         return false;
 279                 if(!send_request(mesh, c, "%d %s", ACK, mykey))
 280                         return false;
 281                 free(mykey);
 282
 283                 c->protocol_minor = 2;
 284
 285                 return sptps_start(&c->sptps, c, false, false, mesh->invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 286         }
 287
 288         /* Check if identity is a valid name */
 289
 290         if(!check_id(name)) {
 291                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
 292                            c->hostname, "invalid name");
 293                 return false;
 294         }
 295
 296         /* If this is an outgoing connection, make sure we are connected to the right host */
 297
 298         if(c->outgoing) {
 299                 if(strcmp(c->name, name)) {
 300                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
 301                                    c->name);
 302                         return false;
 303                 }
 304         } else {
 305                 if(c->name)
 306                         free(c->name);
 307                 c->name = xstrdup(name);
 308         }
 309
 310         /* Check if version matches */
 311
 312         if(c->protocol_major != mesh->self->connection->protocol_major) {
 313                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
 314                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 315                 return false;
 316         }
 317
 318         if(!c->config_tree) {
 319                 init_configuration(&c->config_tree);
 320
 321                 if(!read_host_config(mesh, c->config_tree, c->name)) {
 322                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
 323                         return false;
 324                 }
 325
 326                 read_ecdsa_public_key(mesh, c);
 327         } else {
 328                 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
 329                         c->protocol_minor = 1;
 330         }
 331
 332         /* Forbid version rollback for nodes whose ECDSA key we know */
 333
 334         if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
 335                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
 336                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 337                 return false;
 338         }
 339
 340         c->allow_request = ACK;
 341         char label[25 + strlen(mesh->self->name) + strlen(c->name)];
 342
 343         if(c->outgoing)
 344                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", mesh->self->name, c->name);
 345         else
 346                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, mesh->self->name);
 347
 348         return sptps_start(&c->sptps, c, c->outgoing, false, mesh->self->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 349 }
 350
 351 bool send_ack(meshlink_handle_t *mesh, connection_t *c) {
 352         /* ACK message contains rest of the information the other end needs
 353            to create node_t and edge_t structures. */
 354
 355         struct timeval now;
 356         bool choice;
 357
 358         /* Estimate weight */
 359
 360         gettimeofday(&now, NULL);
 361         c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
 362
 363         /* Check some options */
 364
 365         if(mesh->self->options & OPTION_PMTU_DISCOVERY)
 366                 c->options |= OPTION_PMTU_DISCOVERY;
 367
 368         return send_request(mesh, c, "%d %s %d %x", ACK, mesh->myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 369 }
 370
 371 static void send_everything(meshlink_handle_t *mesh, connection_t *c) {
 372         /* Send all known subnets and edges */
 373
 374         for splay_each(node_t, n, mesh->nodes) {
 375                 for splay_each(edge_t, e, n->edge_tree)
 376                         send_add_edge(mesh, c, e);
 377         }
 378 }
 379
 380 bool ack_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 381         char hisport[MAX_STRING_SIZE];
 382         char *hisaddress;
 383         int weight, mtu;
 384         uint32_t options;
 385         node_t *n;
 386         bool choice;
 387
 388         if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
 389                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 390                            c->hostname);
 391                 return false;
 392         }
 393
 394         /* Check if we already have a node_t for him */
 395
 396         n = lookup_node(mesh, c->name);
 397
 398         if(!n) {
 399                 n = new_node();
 400                 n->name = xstrdup(c->name);
 401                 node_add(mesh, n);
 402         } else {
 403                 if(n->connection) {
 404                         /* Oh dear, we already have a connection to this node. */
 405                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 406
 407                         if(n->connection->outgoing) {
 408                                 if(c->outgoing)
 409                                         logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
 410                                 else
 411                                         c->outgoing = n->connection->outgoing;
 412
 413                                 n->connection->outgoing = NULL;
 414                         }
 415
 416                         terminate_connection(mesh, n->connection, false);
 417                         /* Run graph algorithm to keep things in sync */
 418                         graph(mesh);
 419                 }
 420         }
 421
 422         n->connection = c;
 423         c->node = n;
 424         if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
 425                 c->options &= ~OPTION_PMTU_DISCOVERY;
 426                 options &= ~OPTION_PMTU_DISCOVERY;
 427         }
 428         c->options |= options;
 429
 430         /* Activate this connection */
 431
 432         c->allow_request = ALL;
 433         c->status.active = true;
 434
 435         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 436                            c->hostname);
 437
 438         /* Send him everything we know */
 439
 440         send_everything(mesh, c);
 441
 442         /* Create an edge_t for this connection */
 443
 444         c->edge = new_edge();
 445         c->edge->from = mesh->self;
 446         c->edge->to = n;
 447         sockaddr2str(&c->address, &hisaddress, NULL);
 448         c->edge->address = str2sockaddr(hisaddress, hisport);
 449         free(hisaddress);
 450         c->edge->weight = (weight + c->estimated_weight) / 2;
 451         c->edge->connection = c;
 452         c->edge->options = c->options;
 453
 454         edge_add(mesh, c->edge);
 455
 456         /* Notify everyone of the new edge */
 457
 458         send_add_edge(mesh, mesh->everyone, c->edge);
 459
 460         /* Run MST and SSSP algorithms */
 461
 462         graph(mesh);
 463
 464         return true;
 465 }