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 ecdsa_t *invitation_key = NULL;
  44
  45 static bool send_proxyrequest(connection_t *c) {
  46         switch(mesh->proxytype) {
  47                 case PROXY_HTTP: {
  48                         char *host;
  49                         char *port;
  50
  51                         sockaddr2str(&c->address, &host, &port);
  52                         send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
  53                         free(host);
  54                         free(port);
  55                         return true;
  56                 }
  57                 case PROXY_SOCKS4: {
  58                         if(c->address.sa.sa_family != AF_INET) {
  59                                 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
  60                                 return false;
  61                         }
  62                         char s4req[9 + (mesh->proxyuser ? strlen(mesh->proxyuser) : 0)];
  63                         s4req[0] = 4;
  64                         s4req[1] = 1;
  65                         memcpy(s4req + 2, &c->address.in.sin_port, 2);
  66                         memcpy(s4req + 4, &c->address.in.sin_addr, 4);
  67                         if(mesh->proxyuser)
  68                                 memcpy(s4req + 8, mesh->proxyuser, strlen(mesh->proxyuser));
  69                         s4req[sizeof s4req - 1] = 0;
  70                         c->tcplen = 8;
  71                         return send_meta(c, s4req, sizeof s4req);
  72                 }
  73                 case PROXY_SOCKS5: {
  74                         int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
  75                         c->tcplen = 2;
  76                         if(mesh->proxypass)
  77                                 len += 3 + strlen(mesh->proxyuser) + strlen(mesh->proxypass);
  78                         char s5req[len];
  79                         int i = 0;
  80                         s5req[i++] = 5;
  81                         s5req[i++] = 1;
  82                         if(mesh->proxypass) {
  83                                 s5req[i++] = 2;
  84                                 s5req[i++] = 1;
  85                                 s5req[i++] = strlen(mesh->proxyuser);
  86                                 memcpy(s5req + i, mesh->proxyuser, strlen(mesh->proxyuser));
  87                                 i += strlen(mesh->proxyuser);
  88                                 s5req[i++] = strlen(mesh->proxypass);
  89                                 memcpy(s5req + i, mesh->proxypass, strlen(mesh->proxypass));
  90                                 i += strlen(mesh->proxypass);
  91                                 c->tcplen += 2;
  92                         } else {
  93                                 s5req[i++] = 0;
  94                         }
  95                         s5req[i++] = 5;
  96                         s5req[i++] = 1;
  97                         s5req[i++] = 0;
  98                         if(c->address.sa.sa_family == AF_INET) {
  99                                 s5req[i++] = 1;
 100                                 memcpy(s5req + i, &c->address.in.sin_addr, 4);
 101                                 i += 4;
 102                                 memcpy(s5req + i, &c->address.in.sin_port, 2);
 103                                 i += 2;
 104                                 c->tcplen += 10;
 105                         } else if(c->address.sa.sa_family == AF_INET6) {
 106                                 s5req[i++] = 3;
 107                                 memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
 108                                 i += 16;
 109                                 memcpy(s5req + i, &c->address.in6.sin6_port, 2);
 110                                 i += 2;
 111                                 c->tcplen += 22;
 112                         } else {
 113                                 logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
 114                                 return false;
 115                         }
 116                         if(i > len)
 117                                 abort();
 118                         return send_meta(c, s5req, sizeof s5req);
 119                 }
 120                 case PROXY_SOCKS4A:
 121                         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
 122                         return false;
 123                 case PROXY_EXEC:
 124                         return true;
 125                 default:
 126                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
 127                         return false;
 128         }
 129 }
 130
 131 bool send_id(connection_t *c) {
 132         gettimeofday(&c->start, NULL);
 133
 134         int minor = mesh->self->connection->protocol_minor;
 135
 136         if(mesh->proxytype && c->outgoing)
 137                 if(!send_proxyrequest(c))
 138                         return false;
 139
 140         return send_request(c, "%d %s %d.%d", ID, mesh->self->connection->name, mesh->self->connection->protocol_major, minor);
 141 }
 142
 143 static bool finalize_invitation(connection_t *c, const char *data, uint16_t len) {
 144         if(strchr(data, '\n')) {
 145                 logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
 146                 return false;
 147         }
 148
 149         // Create a new host config file
 150         char filename[PATH_MAX];
 151         snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", mesh->confbase, c->name);
 152         if(!access(filename, F_OK)) {
 153                 logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
 154                 return false;
 155         }
 156
 157         FILE *f = fopen(filename, "w");
 158         if(!f) {
 159                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
 160                 return false;
 161         }
 162
 163         fprintf(f, "ECDSAPublicKey = %s\n", data);
 164         fclose(f);
 165
 166         logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
 167
 168         //TODO: callback to application to inform of an accepted invitation
 169
 170         sptps_send_record(&c->sptps, 2, data, 0);
 171         return true;
 172 }
 173
 174 static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
 175         connection_t *c = handle;
 176
 177         if(type == 128)
 178                 return true;
 179
 180         if(type == 1 && c->status.invitation_used)
 181                 return finalize_invitation(c, data, len);
 182
 183         if(type != 0 || len != 18 || c->status.invitation_used)
 184                 return false;
 185
 186         // Recover the filename from the cookie and the key
 187         char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
 188         char hash[64];
 189         char hashbuf[18 + strlen(fingerprint)];
 190         char cookie[25];
 191         memcpy(hashbuf, data, 18);
 192         memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
 193         sha512(hashbuf, sizeof hashbuf, hash);
 194         b64encode_urlsafe(hash, cookie, 18);
 195         free(fingerprint);
 196
 197         char filename[PATH_MAX], usedname[PATH_MAX];
 198         snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookie);
 199         snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, cookie);
 200
 201         // Atomically rename the invitation file
 202         if(rename(filename, usedname)) {
 203                 if(errno == ENOENT)
 204                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
 205                 else
 206                         logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
 207                 return false;
 208         }
 209
 210         // Open the renamed file
 211         FILE *f = fopen(usedname, "r");
 212         if(!f) {
 213                 logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 214                 return false;
 215         }
 216
 217         // Read the new node's Name from the file
 218         char buf[1024];
 219         fgets(buf, sizeof buf, f);
 220         if(*buf)
 221                 buf[strlen(buf) - 1] = 0;
 222
 223         len = strcspn(buf, " \t=");
 224         char *name = buf + len;
 225         name += strspn(name, " \t");
 226         if(*name == '=') {
 227                 name++;
 228                 name += strspn(name, " \t");
 229         }
 230         buf[len] = 0;
 231
 232         if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
 233                 logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
 234                 fclose(f);
 235                 return false;
 236         }
 237
 238         free(c->name);
 239         c->name = xstrdup(name);
 240
 241         // Send the node the contents of the invitation file
 242         rewind(f);
 243         size_t result;
 244         while((result = fread(buf, 1, sizeof buf, f)))
 245                 sptps_send_record(&c->sptps, 0, buf, result);
 246         sptps_send_record(&c->sptps, 1, buf, 0);
 247         fclose(f);
 248         unlink(usedname);
 249
 250         c->status.invitation_used = true;
 251
 252         logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
 253         return true;
 254 }
 255
 256 bool id_h(connection_t *c, const char *request) {
 257         char name[MAX_STRING_SIZE];
 258
 259         if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 260                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 261                            c->hostname);
 262                 return false;
 263         }
 264
 265         /* Check if this is an invitation  */
 266
 267         if(name[0] == '?') {
 268                 if(!invitation_key) {
 269                         logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 270                         return false;
 271                 }
 272
 273                 c->ecdsa = ecdsa_set_base64_public_key(name + 1);
 274                 if(!c->ecdsa) {
 275                         logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 276                         return false;
 277                 }
 278
 279                 c->status.invitation = true;
 280                 char *mykey = ecdsa_get_base64_public_key(invitation_key);
 281                 if(!mykey)
 282                         return false;
 283                 if(!send_request(c, "%d %s", ACK, mykey))
 284                         return false;
 285                 free(mykey);
 286
 287                 c->protocol_minor = 2;
 288
 289                 return sptps_start(&c->sptps, c, false, false, invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 290         }
 291
 292         /* Check if identity is a valid name */
 293
 294         if(!check_id(name)) {
 295                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
 296                            c->hostname, "invalid name");
 297                 return false;
 298         }
 299
 300         /* If this is an outgoing connection, make sure we are connected to the right host */
 301
 302         if(c->outgoing) {
 303                 if(strcmp(c->name, name)) {
 304                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
 305                                    c->name);
 306                         return false;
 307                 }
 308         } else {
 309                 if(c->name)
 310                         free(c->name);
 311                 c->name = xstrdup(name);
 312         }
 313
 314         /* Check if version matches */
 315
 316         if(c->protocol_major != mesh->self->connection->protocol_major) {
 317                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
 318                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 319                 return false;
 320         }
 321
 322         if(bypass_security) {
 323                 if(!c->config_tree)
 324                         init_configuration(&c->config_tree);
 325                 c->allow_request = ACK;
 326                 return send_ack(c);
 327         }
 328
 329         if(!c->config_tree) {
 330                 init_configuration(&c->config_tree);
 331
 332                 if(!read_host_config(c->config_tree, c->name)) {
 333                         logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
 334                         return false;
 335                 }
 336
 337                 read_ecdsa_public_key(c);
 338         } else {
 339                 if(c->protocol_minor && !ecdsa_active(c->ecdsa))
 340                         c->protocol_minor = 1;
 341         }
 342
 343         /* Forbid version rollback for nodes whose ECDSA key we know */
 344
 345         if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
 346                 logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
 347                         c->name, c->hostname, c->protocol_major, c->protocol_minor);
 348                 return false;
 349         }
 350
 351         c->allow_request = ACK;
 352         char label[25 + strlen(mesh->self->name) + strlen(c->name)];
 353
 354         if(c->outgoing)
 355                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", mesh->self->name, c->name);
 356         else
 357                 snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, mesh->self->name);
 358
 359         return sptps_start(&c->sptps, c, c->outgoing, false, mesh->self->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 360 }
 361
 362 bool send_ack(connection_t *c) {
 363         /* ACK message contains rest of the information the other end needs
 364            to create node_t and edge_t structures. */
 365
 366         struct timeval now;
 367         bool choice;
 368
 369         /* Estimate weight */
 370
 371         gettimeofday(&now, NULL);
 372         c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
 373
 374         /* Check some options */
 375
 376         if(mesh->self->options & OPTION_PMTU_DISCOVERY)
 377                 c->options |= OPTION_PMTU_DISCOVERY;
 378
 379         return send_request(c, "%d %s %d %x", ACK, mesh->myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 380 }
 381
 382 static void send_everything(connection_t *c) {
 383         /* Send all known subnets and edges */
 384
 385         for splay_each(node_t, n, mesh->nodes) {
 386                 for splay_each(edge_t, e, n->edge_tree)
 387                         send_add_edge(c, e);
 388         }
 389 }
 390
 391 bool ack_h(connection_t *c, const char *request) {
 392         char hisport[MAX_STRING_SIZE];
 393         char *hisaddress;
 394         int weight, mtu;
 395         uint32_t options;
 396         node_t *n;
 397         bool choice;
 398
 399         if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
 400                 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 401                            c->hostname);
 402                 return false;
 403         }
 404
 405         /* Check if we already have a node_t for him */
 406
 407         n = lookup_node(c->name);
 408
 409         if(!n) {
 410                 n = new_node();
 411                 n->name = xstrdup(c->name);
 412                 node_add(n);
 413         } else {
 414                 if(n->connection) {
 415                         /* Oh dear, we already have a connection to this node. */
 416                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 417
 418                         if(n->connection->outgoing) {
 419                                 if(c->outgoing)
 420                                         logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
 421                                 else
 422                                         c->outgoing = n->connection->outgoing;
 423
 424                                 n->connection->outgoing = NULL;
 425                         }
 426
 427                         terminate_connection(n->connection, false);
 428                         /* Run graph algorithm to keep things in sync */
 429                         graph();
 430                 }
 431         }
 432
 433         n->connection = c;
 434         c->node = n;
 435         if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
 436                 c->options &= ~OPTION_PMTU_DISCOVERY;
 437                 options &= ~OPTION_PMTU_DISCOVERY;
 438         }
 439         c->options |= options;
 440
 441         /* Activate this connection */
 442
 443         c->allow_request = ALL;
 444         c->status.active = true;
 445
 446         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 447                            c->hostname);
 448
 449         /* Send him everything we know */
 450
 451         send_everything(c);
 452
 453         /* Create an edge_t for this connection */
 454
 455         c->edge = new_edge();
 456         c->edge->from = mesh->self;
 457         c->edge->to = n;
 458         sockaddr2str(&c->address, &hisaddress, NULL);
 459         c->edge->address = str2sockaddr(hisaddress, hisport);
 460         free(hisaddress);
 461         c->edge->weight = (weight + c->estimated_weight) / 2;
 462         c->edge->connection = c;
 463         c->edge->options = c->options;
 464
 465         edge_add(c->edge);
 466
 467         /* Notify everyone of the new edge */
 468
 469         send_add_edge(everyone, c->edge);
 470
 471         /* Run MST and SSSP algorithms */
 472
 473         graph();
 474
 475         return true;
 476 }