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 "meshlink_internal.h"
  32 #include "meta.h"
  33 #include "net.h"
  34 #include "netutl.h"
  35 #include "node.h"
  36 #include "prf.h"
  37 #include "protocol.h"
  38 #include "sptps.h"
  39 #include "utils.h"
  40 #include "xalloc.h"
  41 #include "ed25519/sha512.h"
  42
  43 static bool send_proxyrequest(connection_t *c) {
  44         switch(mesh->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 + (mesh->proxyuser ? strlen(mesh->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(mesh->proxyuser)
  66                                 memcpy(s4req + 8, mesh->proxyuser, strlen(mesh->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(mesh->proxypass)
  75                                 len += 3 + strlen(mesh->proxyuser) + strlen(mesh->proxypass);
  76                         char s5req[len];
  77                         int i = 0;
  78                         s5req[i++] = 5;
  79                         s5req[i++] = 1;
  80                         if(mesh->proxypass) {
  81                                 s5req[i++] = 2;
  82                                 s5req[i++] = 1;
  83                                 s5req[i++] = strlen(mesh->proxyuser);
  84                                 memcpy(s5req + i, mesh->proxyuser, strlen(mesh->proxyuser));
  85                                 i += strlen(mesh->proxyuser);
  86                                 s5req[i++] = strlen(mesh->proxypass);
  87                                 memcpy(s5req + i, mesh->proxypass, strlen(mesh->proxypass));
  88                                 i += strlen(mesh->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 = mesh->self->connection->protocol_minor;
 133
 134         if(mesh->proxytype && c->outgoing)
 135                 if(!send_proxyrequest(c))
 136                         return false;
 137
 138         return send_request(c, "%d %s %d.%d", ID, mesh->self->connection->name, mesh->self->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", mesh->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         char *fingerprint = ecdsa_get_base64_public_key(mesh->invitation_key);
 186         char hash[64];
 187         char hashbuf[18 + strlen(fingerprint)];
 188         char cookie[25];
 189         memcpy(hashbuf, data, 18);
 190         memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
 191         sha512(hashbuf, sizeof hashbuf, hash);
 192         b64encode_urlsafe(hash, cookie, 18);
 193         free(fingerprint);
 194
 195         char filename[PATH_MAX], usedname[PATH_MAX];
 196         snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookie);
 197         snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, cookie);
 198
 199         // Atomically rename the invitation file
 200         if(rename(filename, usedname)) {
 201                 if(errno == ENOENT)
 202                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
 203                 else
 204                         logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
 205                 return false;
 206         }
 207
 208         // Open the renamed file
 209         FILE *f = fopen(usedname, "r");
 210         if(!f) {
 211                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 212                 return false;
 213         }
 214
 215         // Read the new node's Name from the file
 216         char buf[1024];
 217         fgets(buf, sizeof buf, f);
 218         if(*buf)
 219                 buf[strlen(buf) - 1] = 0;
 220
 221         len = strcspn(buf, " \t=");
 222         char *name = buf + len;
 223         name += strspn(name, " \t");
 224         if(*name == '=') {
 225                 name++;
 226                 name += strspn(name, " \t");
 227         }
 228         buf[len] = 0;
 229
 230         if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
 231                 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
 232                 fclose(f);
 233                 return false;
 234         }
 235
 236         free(c->name);
 237         c->name = xstrdup(name);
 238
 239         // Send the node the contents of the invitation file
 240         rewind(f);
 241         size_t result;
 242         while((result = fread(buf, 1, sizeof buf, f)))
 243                 sptps_send_record(&c->sptps, 0, buf, result);
 244         sptps_send_record(&c->sptps, 1, buf, 0);
 245         fclose(f);
 246         unlink(usedname);
 247
 248         c->status.invitation_used = true;
 249
 250         logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
 251         return true;
 252 }
 253
 254 bool id_h(connection_t *c, const char *request) {
 255         char name[MAX_STRING_SIZE];
 256
 257         if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 258                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 259                            c->hostname);
 260                 return false;
 261         }
 262
 263         /* Check if this is an invitation  */
 264
 265         if(name[0] == '?') {
 266                 if(!mesh->invitation_key) {
 267                         logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 268                         return false;
 269                 }
 270
 271                 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
 272                 if(!c->ecdsa) {
 273                         logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 274                         return false;
 275                 }
 276
 277                 c->status.invitation = true;
 278                 char *mykey = ecdsa_get_base64_public_key(mesh->invitation_key);
 279                 if(!mykey)
 280                         return false;
 281                 if(!send_request(c, "%d %s", ACK, mykey))
 282                         return false;
 283                 free(mykey);
 284
 285                 c->protocol_minor = 2;
 286
 287                 return sptps_start(&c->sptps, c, false, false, mesh->invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 288         }
 289
 290         /* Check if identity is a valid name */
 291
 292         if(!check_id(name)) {
 293                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
 294                            c->hostname, "invalid name");
 295                 return false;
 296         }
 297
 298         /* If this is an outgoing connection, make sure we are connected to the right host */
 299
 300         if(c->outgoing) {
 301                 if(strcmp(c->name, name)) {
 302                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
 303                                    c->name);
 304                         return false;
 305                 }
 306         } else {
 307                 if(c->name)
 308                         free(c->name);
 309                 c->name = xstrdup(name);
 310         }
 311
 312         /* Check if version matches */
 313
 314         if(c->protocol_major != mesh->self->connection->protocol_major) {
 315                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
 316                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 317                 return false;
 318         }
 319
 320         if(bypass_security) {
 321                 if(!c->config_tree)
 322                         init_configuration(&c->config_tree);
 323                 c->allow_request = ACK;
 324                 return send_ack(c);
 325         }
 326
 327         if(!c->config_tree) {
 328                 init_configuration(&c->config_tree);
 329
 330                 if(!read_host_config(c->config_tree, c->name)) {
 331                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
 332                         return false;
 333                 }
 334
 335                 read_ecdsa_public_key(c);
 336         } else {
 337                 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
 338                         c->protocol_minor = 1;
 339         }
 340
 341         /* Forbid version rollback for nodes whose ECDSA key we know */
 342
 343         if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
 344                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
 345                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 346                 return false;
 347         }
 348
 349         c->allow_request = ACK;
 350         char label[25 + strlen(mesh->self->name) + strlen(c->name)];
 351
 352         if(c->outgoing)
 353                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", mesh->self->name, c->name);
 354         else
 355                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, mesh->self->name);
 356
 357         return sptps_start(&c->sptps, c, c->outgoing, false, mesh->self->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 358 }
 359
 360 bool send_ack(connection_t *c) {
 361         /* ACK message contains rest of the information the other end needs
 362            to create node_t and edge_t structures. */
 363
 364         struct timeval now;
 365         bool choice;
 366
 367         /* Estimate weight */
 368
 369         gettimeofday(&now, NULL);
 370         c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
 371
 372         /* Check some options */
 373
 374         if(mesh->self->options & OPTION_PMTU_DISCOVERY)
 375                 c->options |= OPTION_PMTU_DISCOVERY;
 376
 377         return send_request(c, "%d %s %d %x", ACK, mesh->myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 378 }
 379
 380 static void send_everything(connection_t *c) {
 381         /* Send all known subnets and edges */
 382
 383         for splay_each(node_t, n, mesh->nodes) {
 384                 for splay_each(edge_t, e, n->edge_tree)
 385                         send_add_edge(c, e);
 386         }
 387 }
 388
 389 bool ack_h(connection_t *c, const char *request) {
 390         char hisport[MAX_STRING_SIZE];
 391         char *hisaddress;
 392         int weight, mtu;
 393         uint32_t options;
 394         node_t *n;
 395         bool choice;
 396
 397         if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
 398                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 399                            c->hostname);
 400                 return false;
 401         }
 402
 403         /* Check if we already have a node_t for him */
 404
 405         n = lookup_node(c->name);
 406
 407         if(!n) {
 408                 n = new_node();
 409                 n->name = xstrdup(c->name);
 410                 node_add(n);
 411         } else {
 412                 if(n->connection) {
 413                         /* Oh dear, we already have a connection to this node. */
 414                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 415
 416                         if(n->connection->outgoing) {
 417                                 if(c->outgoing)
 418                                         logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
 419                                 else
 420                                         c->outgoing = n->connection->outgoing;
 421
 422                                 n->connection->outgoing = NULL;
 423                         }
 424
 425                         terminate_connection(n->connection, false);
 426                         /* Run graph algorithm to keep things in sync */
 427                         graph();
 428                 }
 429         }
 430
 431         n->connection = c;
 432         c->node = n;
 433         if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
 434                 c->options &= ~OPTION_PMTU_DISCOVERY;
 435                 options &= ~OPTION_PMTU_DISCOVERY;
 436         }
 437         c->options |= options;
 438
 439         /* Activate this connection */
 440
 441         c->allow_request = ALL;
 442         c->status.active = true;
 443
 444         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 445                            c->hostname);
 446
 447         /* Send him everything we know */
 448
 449         send_everything(c);
 450
 451         /* Create an edge_t for this connection */
 452
 453         c->edge = new_edge();
 454         c->edge->from = mesh->self;
 455         c->edge->to = n;
 456         sockaddr2str(&c->address, &hisaddress, NULL);
 457         c->edge->address = str2sockaddr(hisaddress, hisport);
 458         free(hisaddress);
 459         c->edge->weight = (weight + c->estimated_weight) / 2;
 460         c->edge->connection = c;
 461         c->edge->options = c->options;
 462
 463         edge_add(c->edge);
 464
 465         /* Notify everyone of the new edge */
 466
 467         send_add_edge(mesh->everyone, c->edge);
 468
 469         /* Run MST and SSSP algorithms */
 470
 471         graph();
 472
 473         return true;
 474 }