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 "cipher.h"
  25 #include "crypto.h"
  26 #include "digest.h"
  27 #include "ecdsa.h"
  28 #include "edge.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "node.h"
  35 #include "prf.h"
  36 #include "protocol.h"
  37 #include "sptps.h"
  38 #include "utils.h"
  39 #include "xalloc.h"
  40
  41 ecdsa_t *invitation_key = NULL;
  42
  43 static bool send_proxyrequest(connection_t *c) {
  44         switch(proxytype) {
  45                 case PROXY_HTTP: {
  46                         char *host;
  47                         char *port;
  48
  49                         sockaddr2str(&c->address, &host, &port);
  50                         send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
  51                         free(host);
  52                         free(port);
  53                         return true;
  54                 }
  55                 case PROXY_SOCKS4: {
  56                         if(c->address.sa.sa_family != AF_INET) {
  57                                 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
  58                                 return false;
  59                         }
  60                         char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
  61                         s4req[0] = 4;
  62                         s4req[1] = 1;
  63                         memcpy(s4req + 2, &c->address.in.sin_port, 2);
  64                         memcpy(s4req + 4, &c->address.in.sin_addr, 4);
  65                         if(proxyuser)
  66                                 memcpy(s4req + 8, proxyuser, strlen(proxyuser));
  67                         s4req[sizeof s4req - 1] = 0;
  68                         c->tcplen = 8;
  69                         return send_meta(c, s4req, sizeof s4req);
  70                 }
  71                 case PROXY_SOCKS5: {
  72                         int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
  73                         c->tcplen = 2;
  74                         if(proxypass)
  75                                 len += 3 + strlen(proxyuser) + strlen(proxypass);
  76                         char s5req[len];
  77                         int i = 0;
  78                         s5req[i++] = 5;
  79                         s5req[i++] = 1;
  80                         if(proxypass) {
  81                                 s5req[i++] = 2;
  82                                 s5req[i++] = 1;
  83                                 s5req[i++] = strlen(proxyuser);
  84                                 memcpy(s5req + i, proxyuser, strlen(proxyuser));
  85                                 i += strlen(proxyuser);
  86                                 s5req[i++] = strlen(proxypass);
  87                                 memcpy(s5req + i, proxypass, strlen(proxypass));
  88                                 i += strlen(proxypass);
  89                                 c->tcplen += 2;
  90                         } else {
  91                                 s5req[i++] = 0;
  92                         }
  93                         s5req[i++] = 5;
  94                         s5req[i++] = 1;
  95                         s5req[i++] = 0;
  96                         if(c->address.sa.sa_family == AF_INET) {
  97                                 s5req[i++] = 1;
  98                                 memcpy(s5req + i, &c->address.in.sin_addr, 4);
  99                                 i += 4;
 100                                 memcpy(s5req + i, &c->address.in.sin_port, 2);
 101                                 i += 2;
 102                                 c->tcplen += 10;
 103                         } else if(c->address.sa.sa_family == AF_INET6) {
 104                                 s5req[i++] = 3;
 105                                 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
 106                                 i += 16;
 107                                 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
 108                                 i += 2;
 109                                 c->tcplen += 22;
 110                         } else {
 111                                 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
 112                                 return false;
 113                         }
 114                         if(i > len)
 115                                 abort();
 116                         return send_meta(c, s5req, sizeof s5req);
 117                 }
 118                 case PROXY_SOCKS4A:
 119                         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
 120                         return false;
 121                 case PROXY_EXEC:
 122                         return true;
 123                 default:
 124                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
 125                         return false;
 126         }
 127 }
 128
 129 bool send_id(connection_t *c) {
 130         gettimeofday(&c->start, NULL);
 131
 132         int minor = myself->connection->protocol_minor;
 133
 134         if(proxytype && c->outgoing)
 135                 if(!send_proxyrequest(c))
 136                         return false;
 137
 138         return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
 139 }
 140
 141 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
 142         if(strchr(data, '\n')) {
 143                 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
 144                 return false;
 145         }
 146
 147         // Create a new host config file
 148         char filename[PATH_MAX];
 149         snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 150         if(!access(filename, F_OK)) {
 151                 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
 152                 return false;
 153         }
 154
 155         FILE *f = fopen(filename, "w");
 156         if(!f) {
 157                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
 158                 return false;
 159         }
 160
 161         fprintf(f, "ECDSAPublicKey = %s\n", data);
 162         fclose(f);
 163
 164         logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
 165
 166         //TODO: callback to application to inform of an accepted invitation
 167
 168         sptps_send_record(&c->sptps, 2, data, 0);
 169         return true;
 170 }
 171
 172 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
 173         connection_t *c = handle;
 174
 175         if(type == 128)
 176                 return true;
 177
 178         if(type == 1 && c->status.invitation_used)
 179                 return finalize_invitation(c, data, len);
 180
 181         if(type != 0 || len != 18 || c->status.invitation_used)
 182                 return false;
 183
 184         // Recover the filename from the cookie and the key
 185         digest_t *digest = digest_open_by_name("sha256", 18);
 186         if(!digest)
 187                 abort();
 188         char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
 189         char hashbuf[18 + strlen(fingerprint)];
 190         char cookie[25];
 191         memcpy(hashbuf, data, 18);
 192         memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
 193         digest_create(digest, hashbuf, sizeof hashbuf, cookie);
 194         b64encode_urlsafe(cookie, cookie, 18);
 195         digest_close(digest);
 196         free(fingerprint);
 197
 198         char filename[PATH_MAX], usedname[PATH_MAX];
 199         snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
 200         snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
 201
 202         // Atomically rename the invitation file
 203         if(rename(filename, usedname)) {
 204                 if(errno == ENOENT)
 205                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
 206                 else
 207                         logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
 208                 return false;
 209         }
 210
 211         // Open the renamed file
 212         FILE *f = fopen(usedname, "r");
 213         if(!f) {
 214                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 215                 return false;
 216         }
 217
 218         // Read the new node's Name from the file
 219         char buf[1024];
 220         fgets(buf, sizeof buf, f);
 221         if(*buf)
 222                 buf[strlen(buf) - 1] = 0;
 223
 224         len = strcspn(buf, " \t=");
 225         char *name = buf + len;
 226         name += strspn(name, " \t");
 227         if(*name == '=') {
 228                 name++;
 229                 name += strspn(name, " \t");
 230         }
 231         buf[len] = 0;
 232
 233         if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
 234                 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
 235                 fclose(f);
 236                 return false;
 237         }
 238
 239         free(c->name);
 240         c->name = xstrdup(name);
 241
 242         // Send the node the contents of the invitation file
 243         rewind(f);
 244         size_t result;
 245         while((result = fread(buf, 1, sizeof buf, f)))
 246                 sptps_send_record(&c->sptps, 0, buf, result);
 247         sptps_send_record(&c->sptps, 1, buf, 0);
 248         fclose(f);
 249         unlink(usedname);
 250
 251         c->status.invitation_used = true;
 252
 253         logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
 254         return true;
 255 }
 256
 257 bool id_h(connection_t *c, const char *request) {
 258         char name[MAX_STRING_SIZE];
 259
 260         if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 261                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 262                            c->hostname);
 263                 return false;
 264         }
 265
 266         /* Check if this is an invitation  */
 267
 268         if(name[0] == '?') {
 269                 if(!invitation_key) {
 270                         logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 271                         return false;
 272                 }
 273
 274                 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
 275                 if(!c->ecdsa) {
 276                         logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 277                         return false;
 278                 }
 279
 280                 c->status.invitation = true;
 281                 char *mykey = ecdsa_get_base64_public_key(invitation_key);
 282                 if(!mykey)
 283                         return false;
 284                 if(!send_request(c, "%d %s", ACK, mykey))
 285                         return false;
 286                 free(mykey);
 287
 288                 c->protocol_minor = 2;
 289
 290                 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 291         }
 292
 293         /* Check if identity is a valid name */
 294
 295         if(!check_id(name)) {
 296                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
 297                            c->hostname, "invalid name");
 298                 return false;
 299         }
 300
 301         /* If this is an outgoing connection, make sure we are connected to the right host */
 302
 303         if(c->outgoing) {
 304                 if(strcmp(c->name, name)) {
 305                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
 306                                    c->name);
 307                         return false;
 308                 }
 309         } else {
 310                 if(c->name)
 311                         free(c->name);
 312                 c->name = xstrdup(name);
 313         }
 314
 315         /* Check if version matches */
 316
 317         if(c->protocol_major != myself->connection->protocol_major) {
 318                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
 319                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 320                 return false;
 321         }
 322
 323         if(bypass_security) {
 324                 if(!c->config_tree)
 325                         init_configuration(&c->config_tree);
 326                 c->allow_request = ACK;
 327                 return send_ack(c);
 328         }
 329
 330         if(!c->config_tree) {
 331                 init_configuration(&c->config_tree);
 332
 333                 if(!read_host_config(c->config_tree, c->name)) {
 334                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
 335                         return false;
 336                 }
 337
 338                 read_ecdsa_public_key(c);
 339         } else {
 340                 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
 341                         c->protocol_minor = 1;
 342         }
 343
 344         /* Forbid version rollback for nodes whose ECDSA key we know */
 345
 346         if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
 347                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
 348                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 349                 return false;
 350         }
 351
 352         c->allow_request = ACK;
 353         char label[25 + strlen(myself->name) + strlen(c->name)];
 354
 355         if(c->outgoing)
 356                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
 357         else
 358                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
 359
 360         return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 361 }
 362
 363 bool send_ack(connection_t *c) {
 364         /* ACK message contains rest of the information the other end needs
 365            to create node_t and edge_t structures. */
 366
 367         struct timeval now;
 368         bool choice;
 369
 370         /* Estimate weight */
 371
 372         gettimeofday(&now, NULL);
 373         c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
 374
 375         /* Check some options */
 376
 377         if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
 378                 c->options |= OPTION_INDIRECT;
 379
 380         if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
 381                 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
 382
 383         if(myself->options & OPTION_PMTU_DISCOVERY)
 384                 c->options |= OPTION_PMTU_DISCOVERY;
 385
 386         choice = myself->options & OPTION_CLAMP_MSS;
 387         get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
 388         if(choice)
 389                 c->options |= OPTION_CLAMP_MSS;
 390
 391         if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
 392                 get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
 393
 394         return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 395 }
 396
 397 static void send_everything(connection_t *c) {
 398         /* Send all known subnets and edges */
 399
 400         // TODO: remove this
 401         if(disablebuggypeers) {
 402                 static struct {
 403                         vpn_packet_t pkt;
 404                         char pad[MAXBUFSIZE - MAXSIZE];
 405                 } zeropkt;
 406
 407                 memset(&zeropkt, 0, sizeof zeropkt);
 408                 zeropkt.pkt.len = MAXBUFSIZE;
 409                 send_tcppacket(c, &zeropkt.pkt);
 410         }
 411
 412         for splay_each(node_t, n, node_tree) {
 413                 for splay_each(edge_t, e, n->edge_tree)
 414                         send_add_edge(c, e);
 415         }
 416 }
 417
 418 bool ack_h(connection_t *c, const char *request) {
 419         char hisport[MAX_STRING_SIZE];
 420         char *hisaddress;
 421         int weight, mtu;
 422         uint32_t options;
 423         node_t *n;
 424         bool choice;
 425
 426         if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
 427                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 428                            c->hostname);
 429                 return false;
 430         }
 431
 432         /* Check if we already have a node_t for him */
 433
 434         n = lookup_node(c->name);
 435
 436         if(!n) {
 437                 n = new_node();
 438                 n->name = xstrdup(c->name);
 439                 node_add(n);
 440         } else {
 441                 if(n->connection) {
 442                         /* Oh dear, we already have a connection to this node. */
 443                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 444
 445                         if(n->connection->outgoing) {
 446                                 if(c->outgoing)
 447                                         logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
 448                                 else
 449                                         c->outgoing = n->connection->outgoing;
 450
 451                                 n->connection->outgoing = NULL;
 452                         }
 453
 454                         terminate_connection(n->connection, false);
 455                         /* Run graph algorithm to keep things in sync */
 456                         graph();
 457                 }
 458         }
 459
 460         n->connection = c;
 461         c->node = n;
 462         if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
 463                 c->options &= ~OPTION_PMTU_DISCOVERY;
 464                 options &= ~OPTION_PMTU_DISCOVERY;
 465         }
 466         c->options |= options;
 467
 468         if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
 469                 n->mtu = mtu;
 470
 471         if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
 472                 n->mtu = mtu;
 473
 474         if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
 475                 if(choice)
 476                         c->options |= OPTION_CLAMP_MSS;
 477                 else
 478                         c->options &= ~OPTION_CLAMP_MSS;
 479         }
 480
 481         /* Activate this connection */
 482
 483         c->allow_request = ALL;
 484         c->status.active = true;
 485
 486         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 487                            c->hostname);
 488
 489         /* Send him everything we know */
 490
 491         send_everything(c);
 492
 493         /* Create an edge_t for this connection */
 494
 495         c->edge = new_edge();
 496         c->edge->from = myself;
 497         c->edge->to = n;
 498         sockaddr2str(&c->address, &hisaddress, NULL);
 499         c->edge->address = str2sockaddr(hisaddress, hisport);
 500         free(hisaddress);
 501         c->edge->weight = (weight + c->estimated_weight) / 2;
 502         c->edge->connection = c;
 503         c->edge->options = c->options;
 504
 505         edge_add(c->edge);
 506
 507         /* Notify everyone of the new edge */
 508
 509         send_add_edge(everyone, c->edge);
 510
 511         /* Run MST and SSSP algorithms */
 512
 513         graph();
 514
 515         return true;
 516 }