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