tinc-vpn.org Git - tinc/blob - src/meta.c

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2000-2018 Guus Sliepen <guus@tinc-vpn.org>,
   4                   2000-2005 Ivo Timmermans
   5                   2006      Scott Lamb <slamb@slamb.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "cipher.h"
  25 #include "connection.h"
  26 #include "logger.h"
  27 #include "meta.h"
  28 #include "net.h"
  29 #include "protocol.h"
  30 #include "utils.h"
  31 #include "xalloc.h"
  32
  33 #ifndef MIN
  34 static ssize_t MIN(ssize_t x, ssize_t y) {
  35         return x < y ? x : y;
  36 }
  37 #endif
  38
  39 bool send_meta_sptps(void *handle, uint8_t type, const void *buffer, size_t length) {
  40         (void)type;
  41         connection_t *c = handle;
  42
  43         if(!c) {
  44                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  45                 abort();
  46         }
  47
  48         buffer_add(&c->outbuf, buffer, length);
  49         io_set(&c->io, IO_READ | IO_WRITE);
  50
  51         return true;
  52 }
  53
  54 bool send_meta(connection_t *c, const char *buffer, size_t length) {
  55         if(!c) {
  56                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  57                 abort();
  58         }
  59
  60         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of metadata to %s (%s)", (unsigned long)length,
  61                c->name, c->hostname);
  62
  63         if(c->protocol_minor >= 2) {
  64                 return sptps_send_record(&c->sptps, 0, buffer, length);
  65         }
  66
  67         /* Add our data to buffer */
  68         if(c->status.encryptout) {
  69 #ifdef DISABLE_LEGACY
  70                 return false;
  71 #else
  72
  73                 if(length > c->outbudget) {
  74                         logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname);
  75                         return false;
  76                 } else {
  77                         c->outbudget -= length;
  78                 }
  79
  80                 size_t outlen = length;
  81
  82                 if(!cipher_encrypt(c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  83                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  84                                c->name, c->hostname);
  85                         return false;
  86                 }
  87
  88 #endif
  89         } else {
  90                 buffer_add(&c->outbuf, buffer, length);
  91         }
  92
  93         io_set(&c->io, IO_READ | IO_WRITE);
  94
  95         return true;
  96 }
  97
  98 void send_meta_raw(connection_t *c, const char *buffer, size_t length) {
  99         if(!c) {
 100                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
 101                 abort();
 102         }
 103
 104         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of raw metadata to %s (%s)", (unsigned long)length,
 105                c->name, c->hostname);
 106
 107         buffer_add(&c->outbuf, buffer, length);
 108
 109         io_set(&c->io, IO_READ | IO_WRITE);
 110 }
 111
 112 void broadcast_meta(connection_t *from, const char *buffer, size_t length) {
 113         for list_each(connection_t, c, connection_list)
 114                 if(c != from && c->edge) {
 115                         send_meta(c, buffer, length);
 116                 }
 117 }
 118
 119 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
 120         const char *data = vdata;
 121         connection_t *c = handle;
 122
 123         if(!c) {
 124                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
 125                 abort();
 126         }
 127
 128         if(type == SPTPS_HANDSHAKE) {
 129                 if(c->allow_request == ACK) {
 130                         return send_ack(c);
 131                 } else {
 132                         return true;
 133                 }
 134         }
 135
 136         if(!data) {
 137                 return true;
 138         }
 139
 140         /* Are we receiving a TCPpacket? */
 141
 142         if(c->tcplen) {
 143                 if(length != c->tcplen) {
 144                         return false;
 145                 }
 146
 147                 receive_tcppacket(c, data, length);
 148                 c->tcplen = 0;
 149                 return true;
 150         }
 151
 152         /* Change newline to null byte, just like non-SPTPS requests */
 153
 154         if(data[length - 1] == '\n') {
 155                 ((char *)data)[length - 1] = 0;
 156         }
 157
 158         /* Otherwise we are waiting for a request */
 159
 160         return receive_request(c, data);
 161 }
 162
 163 bool receive_meta(connection_t *c) {
 164         ssize_t inlen;
 165         char inbuf[MAXBUFSIZE];
 166         char *bufp = inbuf, *endp;
 167
 168         /* Strategy:
 169            - Read as much as possible from the TCP socket in one go.
 170            - Decrypt it.
 171            - Check if a full request is in the input buffer.
 172            - If yes, process request and remove it from the buffer,
 173            then check again.
 174            - If not, keep stuff in buffer and exit.
 175          */
 176
 177         buffer_compact(&c->inbuf, MAXBUFSIZE);
 178
 179         if(sizeof(inbuf) <= c->inbuf.len) {
 180                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 181                 return false;
 182         }
 183
 184         inlen = recv(c->socket, inbuf, sizeof(inbuf) - c->inbuf.len, 0);
 185
 186         if(inlen <= 0) {
 187                 if(!inlen || !sockerrno) {
 188                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 189                                c->name, c->hostname);
 190                 } else if(sockwouldblock(sockerrno)) {
 191                         return true;
 192                 } else
 193                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 194                                c->name, c->hostname, sockstrerror(sockerrno));
 195
 196                 return false;
 197         }
 198
 199         do {
 200                 /* Are we receiving a SPTPS packet? */
 201
 202                 if(c->sptpslen) {
 203                         ssize_t len = MIN(inlen, c->sptpslen - c->inbuf.len);
 204                         buffer_add(&c->inbuf, bufp, len);
 205
 206                         char *sptpspacket = buffer_read(&c->inbuf, c->sptpslen);
 207
 208                         if(!sptpspacket) {
 209                                 return true;
 210                         }
 211
 212                         if(!receive_tcppacket_sptps(c, sptpspacket, c->sptpslen)) {
 213                                 return false;
 214                         }
 215
 216                         c->sptpslen = 0;
 217
 218                         bufp += len;
 219                         inlen -= len;
 220                         continue;
 221                 }
 222
 223                 if(c->protocol_minor >= 2) {
 224                         size_t len = sptps_receive_data(&c->sptps, bufp, inlen);
 225
 226                         if(!len) {
 227                                 return false;
 228                         }
 229
 230                         bufp += len;
 231                         inlen -= len;
 232                         continue;
 233                 }
 234
 235                 if(!c->status.decryptin) {
 236                         endp = memchr(bufp, '\n', inlen);
 237
 238                         if(endp) {
 239                                 endp++;
 240                         } else {
 241                                 endp = bufp + inlen;
 242                         }
 243
 244                         buffer_add(&c->inbuf, bufp, endp - bufp);
 245
 246                         inlen -= endp - bufp;
 247                         bufp = endp;
 248                 } else {
 249 #ifdef DISABLE_LEGACY
 250                         return false;
 251 #else
 252
 253                         if((size_t)inlen > c->inbudget) {
 254                                 logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for decryption from %s (%s)", c->name, c->hostname);
 255                                 return false;
 256                         } else {
 257                                 c->inbudget -= inlen;
 258                         }
 259
 260                         size_t outlen = inlen;
 261
 262                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || (size_t)inlen != outlen) {
 263                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 264                                        c->name, c->hostname);
 265                                 return false;
 266                         }
 267
 268                         inlen = 0;
 269 #endif
 270                 }
 271
 272                 while(c->inbuf.len) {
 273                         /* Are we receiving a TCPpacket? */
 274
 275                         if(c->tcplen) {
 276                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 277
 278                                 if(!tcpbuffer) {
 279                                         break;
 280                                 }
 281
 282                                 if(!c->node) {
 283                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 284                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 285                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 286                                                 } else {
 287                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 288                                                         return false;
 289                                                 }
 290                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 291                                                 if(tcpbuffer[0] != 5) {
 292                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 293                                                         return false;
 294                                                 }
 295
 296                                                 if(tcpbuffer[1] == (char)0xff) {
 297                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 298                                                         return false;
 299                                                 }
 300
 301                                                 if(tcpbuffer[2] != 5) {
 302                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 303                                                         return false;
 304                                                 }
 305
 306                                                 if(tcpbuffer[3] == 0) {
 307                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 308                                                 } else {
 309                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 310                                                         return false;
 311                                                 }
 312                                         } else {
 313                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 314                                                 abort();
 315                                         }
 316                                 } else {
 317                                         if(c->allow_request == ALL) {
 318                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 319                                         } else {
 320                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 321                                                 return false;
 322                                         }
 323                                 }
 324
 325                                 c->tcplen = 0;
 326                         }
 327
 328                         /* Otherwise we are waiting for a request */
 329
 330                         char *request = buffer_readline(&c->inbuf);
 331
 332                         if(request) {
 333                                 bool result = receive_request(c, request);
 334
 335                                 if(!result) {
 336                                         return false;
 337                                 }
 338
 339                                 continue;
 340                         } else {
 341                                 break;
 342                         }
 343                 }
 344         } while(inlen);
 345
 346         return true;
 347 }