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(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(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(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(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(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(c))
 133                         return false;
 134
 135         return send_request(c, "%d %s %d.%d", ID, mesh->self->connection->name, mesh->self->connection->protocol_major, minor);
 136 }
 137
 138 static bool finalize_invitation(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
 172         if(type == 128)
 173                 return true;
 174
 175         if(type == 1 && c->status.invitation_used)
 176                 return finalize_invitation(c, data, len);
 177
 178         if(type != 0 || len != 18 || c->status.invitation_used)
 179                 return false;
 180
 181         // Recover the filename from the cookie and the key
 182         char *fingerprint = ecdsa_get_base64_public_key(mesh->invitation_key);
 183         char hash[64];
 184         char hashbuf[18 + strlen(fingerprint)];
 185         char cookie[25];
 186         memcpy(hashbuf, data, 18);
 187         memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
 188         sha512(hashbuf, sizeof hashbuf, hash);
 189         b64encode_urlsafe(hash, cookie, 18);
 190         free(fingerprint);
 191
 192         char filename[PATH_MAX], usedname[PATH_MAX];
 193         snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookie);
 194         snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, cookie);
 195
 196         // Atomically rename the invitation file
 197         if(rename(filename, usedname)) {
 198                 if(errno == ENOENT)
 199                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
 200                 else
 201                         logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
 202                 return false;
 203         }
 204
 205         // Open the renamed file
 206         FILE *f = fopen(usedname, "r");
 207         if(!f) {
 208                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 209                 return false;
 210         }
 211
 212         // Read the new node's Name from the file
 213         char buf[1024];
 214         fgets(buf, sizeof buf, f);
 215         if(*buf)
 216                 buf[strlen(buf) - 1] = 0;
 217
 218         len = strcspn(buf, " \t=");
 219         char *name = buf + len;
 220         name += strspn(name, " \t");
 221         if(*name == '=') {
 222                 name++;
 223                 name += strspn(name, " \t");
 224         }
 225         buf[len] = 0;
 226
 227         if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
 228                 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
 229                 fclose(f);
 230                 return false;
 231         }
 232
 233         free(c->name);
 234         c->name = xstrdup(name);
 235
 236         // Send the node the contents of the invitation file
 237         rewind(f);
 238         size_t result;
 239         while((result = fread(buf, 1, sizeof buf, f)))
 240                 sptps_send_record(&c->sptps, 0, buf, result);
 241         sptps_send_record(&c->sptps, 1, buf, 0);
 242         fclose(f);
 243         unlink(usedname);
 244
 245         c->status.invitation_used = true;
 246
 247         logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
 248         return true;
 249 }
 250
 251 bool id_h(connection_t *c, const char *request) {
 252         char name[MAX_STRING_SIZE];
 253
 254         if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 255                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 256                            c->hostname);
 257                 return false;
 258         }
 259
 260         /* Check if this is an invitation  */
 261
 262         if(name[0] == '?') {
 263                 if(!mesh->invitation_key) {
 264                         logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 265                         return false;
 266                 }
 267
 268                 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
 269                 if(!c->ecdsa) {
 270                         logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 271                         return false;
 272                 }
 273
 274                 c->status.invitation = true;
 275                 char *mykey = ecdsa_get_base64_public_key(mesh->invitation_key);
 276                 if(!mykey)
 277                         return false;
 278                 if(!send_request(c, "%d %s", ACK, mykey))
 279                         return false;
 280                 free(mykey);
 281
 282                 c->protocol_minor = 2;
 283
 284                 return sptps_start(&c->sptps, c, false, false, mesh->invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 285         }
 286
 287         /* Check if identity is a valid name */
 288
 289         if(!check_id(name)) {
 290                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
 291                            c->hostname, "invalid name");
 292                 return false;
 293         }
 294
 295         /* If this is an outgoing connection, make sure we are connected to the right host */
 296
 297         if(c->outgoing) {
 298                 if(strcmp(c->name, name)) {
 299                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
 300                                    c->name);
 301                         return false;
 302                 }
 303         } else {
 304                 if(c->name)
 305                         free(c->name);
 306                 c->name = xstrdup(name);
 307         }
 308
 309         /* Check if version matches */
 310
 311         if(c->protocol_major != mesh->self->connection->protocol_major) {
 312                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
 313                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 314                 return false;
 315         }
 316
 317         if(mesh->bypass_security) {
 318                 if(!c->config_tree)
 319                         init_configuration(&c->config_tree);
 320                 c->allow_request = ACK;
 321                 return send_ack(c);
 322         }
 323
 324         if(!c->config_tree) {
 325                 init_configuration(&c->config_tree);
 326
 327                 if(!read_host_config(c->config_tree, c->name)) {
 328                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
 329                         return false;
 330                 }
 331
 332                 read_ecdsa_public_key(c);
 333         } else {
 334                 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
 335                         c->protocol_minor = 1;
 336         }
 337
 338         /* Forbid version rollback for nodes whose ECDSA key we know */
 339
 340         if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
 341                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
 342                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 343                 return false;
 344         }
 345
 346         c->allow_request = ACK;
 347         char label[25 + strlen(mesh->self->name) + strlen(c->name)];
 348
 349         if(c->outgoing)
 350                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", mesh->self->name, c->name);
 351         else
 352                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, mesh->self->name);
 353
 354         return sptps_start(&c->sptps, c, c->outgoing, false, mesh->self->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 355 }
 356
 357 bool send_ack(connection_t *c) {
 358         /* ACK message contains rest of the information the other end needs
 359            to create node_t and edge_t structures. */
 360
 361         struct timeval now;
 362         bool choice;
 363
 364         /* Estimate weight */
 365
 366         gettimeofday(&now, NULL);
 367         c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
 368
 369         /* Check some options */
 370
 371         if(mesh->self->options & OPTION_PMTU_DISCOVERY)
 372                 c->options |= OPTION_PMTU_DISCOVERY;
 373
 374         return send_request(c, "%d %s %d %x", ACK, mesh->myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 375 }
 376
 377 static void send_everything(connection_t *c) {
 378         /* Send all known subnets and edges */
 379
 380         for splay_each(node_t, n, mesh->nodes) {
 381                 for splay_each(edge_t, e, n->edge_tree)
 382                         send_add_edge(c, e);
 383         }
 384 }
 385
 386 bool ack_h(connection_t *c, const char *request) {
 387         char hisport[MAX_STRING_SIZE];
 388         char *hisaddress;
 389         int weight, mtu;
 390         uint32_t options;
 391         node_t *n;
 392         bool choice;
 393
 394         if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
 395                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 396                            c->hostname);
 397                 return false;
 398         }
 399
 400         /* Check if we already have a node_t for him */
 401
 402         n = lookup_node(c->name);
 403
 404         if(!n) {
 405                 n = new_node();
 406                 n->name = xstrdup(c->name);
 407                 node_add(n);
 408         } else {
 409                 if(n->connection) {
 410                         /* Oh dear, we already have a connection to this node. */
 411                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 412
 413                         if(n->connection->outgoing) {
 414                                 if(c->outgoing)
 415                                         logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
 416                                 else
 417                                         c->outgoing = n->connection->outgoing;
 418
 419                                 n->connection->outgoing = NULL;
 420                         }
 421
 422                         terminate_connection(n->connection, false);
 423                         /* Run graph algorithm to keep things in sync */
 424                         graph();
 425                 }
 426         }
 427
 428         n->connection = c;
 429         c->node = n;
 430         if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
 431                 c->options &= ~OPTION_PMTU_DISCOVERY;
 432                 options &= ~OPTION_PMTU_DISCOVERY;
 433         }
 434         c->options |= options;
 435
 436         /* Activate this connection */
 437
 438         c->allow_request = ALL;
 439         c->status.active = true;
 440
 441         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 442                            c->hostname);
 443
 444         /* Send him everything we know */
 445
 446         send_everything(c);
 447
 448         /* Create an edge_t for this connection */
 449
 450         c->edge = new_edge();
 451         c->edge->from = mesh->self;
 452         c->edge->to = n;
 453         sockaddr2str(&c->address, &hisaddress, NULL);
 454         c->edge->address = str2sockaddr(hisaddress, hisport);
 455         free(hisaddress);
 456         c->edge->weight = (weight + c->estimated_weight) / 2;
 457         c->edge->connection = c;
 458         c->edge->options = c->options;
 459
 460         edge_add(c->edge);
 461
 462         /* Notify everyone of the new edge */
 463
 464         send_add_edge(mesh->everyone, c->edge);
 465
 466         /* Run MST and SSSP algorithms */
 467
 468         graph();
 469
 470         return true;
 471 }