socks.c

   1 /*
   2 Copyright (c) 2003-2006 by Juliusz Chroboczek
   3
   4 Permission is hereby granted, free of charge, to any person obtaining a copy
   5 of this software and associated documentation files (the "Software"), to deal
   6 in the Software without restriction, including without limitation the rights
   7 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8 copies of the Software, and to permit persons to whom the Software is
   9 furnished to do so, subject to the following conditions:
  10
  11 The above copyright notice and this permission notice shall be included in
  12 all copies or substantial portions of the Software.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  17 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20 THE SOFTWARE.
  21 */
  22
  23 #include "polipo.h"
  24
  25 #ifdef NO_SOCKS
  26
  27 AtomPtr socksParentProxy = NULL;
  28
  29 void
  30 preinitSocks()
  31 {
  32     return;
  33 }
  34
  35 void
  36 initSocks()
  37 {
  38     return;
  39 }
  40
  41 int
  42 do_socks_connect(char *name, int port,
  43                  int (*handler)(int, SocksRequestPtr),
  44                  void *data)
  45 {
  46     SocksRequestRec request;
  47     request.name = internAtomLowerN(name, strlen(name));
  48     request.port = port;
  49     request.handler = handler;
  50     request.buf = NULL;
  51     request.data = data;
  52
  53     handler(-ENOSYS, &request);
  54     releaseAtom(request.name);
  55     return 1;
  56 }
  57
  58 #else
  59
  60 AtomPtr socksParentProxy = NULL;
  61 AtomPtr socksProxyHost = NULL;
  62 int socksProxyPort = -1;
  63 AtomPtr socksProxyAddress = NULL;
  64 int socksProxyAddressIndex = -1;
  65 AtomPtr socksUserName = NULL;
  66 AtomPtr socksProxyType = NULL;
  67 AtomPtr aSocks4a, aSocks5;
  68
  69 static int socksParentProxySetter(ConfigVariablePtr, void*);
  70 static int socksProxyTypeSetter(ConfigVariablePtr, void*);
  71 static int do_socks_connect_common(SocksRequestPtr);
  72 static int socksDnsHandler(int, GethostbynameRequestPtr);
  73 static int socksConnectHandler(int, FdEventHandlerPtr, ConnectRequestPtr);
  74 static int socksWriteHandler(int, FdEventHandlerPtr, StreamRequestPtr);
  75 static int socksReadHandler(int, FdEventHandlerPtr, StreamRequestPtr);
  76 static int socks5ReadHandler(int, FdEventHandlerPtr, StreamRequestPtr);
  77 static int socks5WriteHandler(int, FdEventHandlerPtr, StreamRequestPtr);
  78 static int socks5ReadHandler2(int, FdEventHandlerPtr, StreamRequestPtr);
  79
  80 void
  81 preinitSocks()
  82 {
  83     aSocks4a = internAtom("socks4a");
  84     aSocks5 = internAtom("socks5");
  85     socksProxyType = retainAtom(aSocks5);
  86     socksUserName = internAtom("");
  87     CONFIG_VARIABLE_SETTABLE(socksParentProxy, CONFIG_ATOM_LOWER,
  88                              socksParentProxySetter,
  89                              "SOCKS parent proxy (host:port)");
  90     CONFIG_VARIABLE_SETTABLE(socksUserName, CONFIG_ATOM,
  91                              configAtomSetter,
  92                              "SOCKS4a user name");
  93     CONFIG_VARIABLE_SETTABLE(socksProxyType, CONFIG_ATOM_LOWER,
  94                              socksProxyTypeSetter,
  95                              "One of socks4a or socks5");
  96 }
  97
  98 static int
  99 socksParentProxySetter(ConfigVariablePtr var, void *value)
 100 {
 101     configAtomSetter(var, value);
 102     initSocks();
 103     return 1;
 104 }
 105
 106 static int
 107 socksProxyTypeSetter(ConfigVariablePtr var, void *value)
 108 {
 109     if(*var->value.a != aSocks4a && *var->value.a != aSocks5) {
 110         do_log(L_ERROR, "Unknown socksProxyType %s\n", (*var->value.a)->string);
 111         return -1;
 112     }
 113
 114     return configAtomSetter(var, value);
 115 }
 116
 117 void
 118 initSocks()
 119 {
 120     int port = -1;
 121     AtomPtr host = NULL, port_atom;
 122     int rc;
 123
 124     if(socksParentProxy) {
 125         rc = atomSplit(socksParentProxy, ':', &host, &port_atom);
 126         if(rc <= 0) {
 127             do_log(L_ERROR, "Couldn't parse socksParentProxy");
 128             exit(1);
 129         }
 130         port = atoi(port_atom->string);
 131         releaseAtom(port_atom);
 132     }
 133
 134     if(socksProxyHost)
 135         releaseAtom(socksProxyHost);
 136     socksProxyHost = host;
 137     socksProxyPort = port;
 138     if(socksProxyAddress)
 139         releaseAtom(socksProxyAddress);
 140     socksProxyAddress = NULL;
 141     socksProxyAddressIndex = -1;
 142
 143     if(socksProxyType != aSocks4a && socksProxyType != aSocks5) {
 144         do_log(L_ERROR, "Unknown socksProxyType %s\n", socksProxyType->string);
 145         exit(1);
 146     }
 147 }
 148
 149 static void
 150 destroySocksRequest(SocksRequestPtr request)
 151 {
 152     releaseAtom(request->name);
 153     if(request->buf)
 154         free(request->buf);
 155     free(request);
 156 }
 157
 158 int
 159 do_socks_connect(char *name, int port,
 160                  int (*handler)(int, SocksRequestPtr),
 161                  void *data)
 162 {
 163     SocksRequestPtr request = malloc(sizeof(SocksRequestRec));
 164     SocksRequestRec request_nomem;
 165     if(request == NULL)
 166         goto nomem;
 167
 168     request->name = internAtomLowerN(name, strlen(name));
 169     if(request->name == NULL) {
 170         free(request);
 171         goto nomem;
 172     }
 173
 174     request->port = port;
 175     request->fd = -1;
 176     request->handler = handler;
 177     request->buf = NULL;
 178     request->data = data;
 179
 180     if(socksProxyAddress == NULL) {
 181         do_gethostbyname(socksProxyHost->string, 0,
 182                          socksDnsHandler,
 183                          request);
 184         return 1;
 185     }
 186
 187     return do_socks_connect_common(request);
 188
 189  nomem:
 190     request_nomem.name = internAtomLowerN(name, strlen(name));
 191     request_nomem.port = port;
 192     request_nomem.handler = handler;
 193     request_nomem.buf = NULL;
 194     request_nomem.data = data;
 195
 196     handler(-ENOMEM, &request_nomem);
 197     releaseAtom(request_nomem.name);
 198     return 1;
 199 }
 200
 201 static int
 202 do_socks_connect_common(SocksRequestPtr request)
 203 {
 204     assert(socksProxyAddressIndex >= 0);
 205
 206     do_connect(retainAtom(socksProxyAddress),
 207                socksProxyAddressIndex,
 208                socksProxyPort,
 209                socksConnectHandler, request);
 210     return 1;
 211 }
 212
 213 static int
 214 socksDnsHandler(int status, GethostbynameRequestPtr grequest)
 215 {
 216     SocksRequestPtr request = grequest->data;
 217     if(status <= 0) {
 218         request->handler(status, request);
 219         destroySocksRequest(request);
 220         return 1;
 221     }
 222
 223     if(grequest->addr->string[0] == DNS_CNAME) {
 224         if(grequest->count > 10) {
 225             do_log(L_ERROR, "DNS CNAME loop.\n");
 226             request->handler(-EDNS_CNAME_LOOP, request);
 227             destroySocksRequest(request);
 228             return 1;
 229         }
 230         do_gethostbyname(grequest->addr->string + 1, grequest->count + 1,
 231                          httpServerConnectionDnsHandler, request);
 232         return 1;
 233     }
 234
 235
 236     socksProxyAddress = retainAtom(grequest->addr);
 237     socksProxyAddressIndex = 0;
 238
 239     do_socks_connect_common(request);
 240     return 1;
 241 }
 242
 243 static int
 244 socksConnectHandler(int status,
 245                     FdEventHandlerPtr event,
 246                     ConnectRequestPtr crequest)
 247 {
 248     SocksRequestPtr request = crequest->data;
 249     int rc;
 250
 251     if(status < 0) {
 252         request->handler(status, request);
 253         destroySocksRequest(request);
 254         return 1;
 255     }
 256
 257     assert(request->fd < 0);
 258     request->fd = crequest->fd;
 259     socksProxyAddressIndex = crequest->index;
 260
 261     rc = setNodelay(request->fd, 1);
 262     if(rc < 0)
 263         do_log_error(L_WARN, errno, "Couldn't disable Nagle's algorithm");
 264
 265     if(socksProxyType == aSocks4a) {
 266         request->buf = malloc(8 +
 267                               socksUserName->length + 1 +
 268                               request->name->length + 1);
 269         if(request->buf == NULL) {
 270             close(request->fd);
 271             request->fd = -1;
 272             request->handler(-ENOMEM, request);
 273             destroySocksRequest(request);
 274             return 1;
 275         }
 276
 277         request->buf[0] = 4;        /* VN */
 278         request->buf[1] = 1;        /* CD = REQUEST */
 279         request->buf[2] = (request->port >> 8) & 0xFF;
 280         request->buf[3] = request->port & 0xFF;
 281         request->buf[4] = request->buf[5] = request->buf[6] = 0;
 282         request->buf[7] = 3;
 283
 284         memcpy(request->buf + 8, socksUserName->string, socksUserName->length);
 285         request->buf[8 + socksUserName->length] = '\0';
 286
 287         memcpy(request->buf + 8 + socksUserName->length + 1,
 288                request->name->string, request->name->length);
 289         request->buf[8 + socksUserName->length + 1 + request->name->length] =
 290             '\0';
 291
 292         do_stream(IO_WRITE, request->fd, 0, request->buf,
 293                   8 + socksUserName->length + 1 + request->name->length + 1,
 294                   socksWriteHandler, request);
 295     } else if(socksProxyType == aSocks5) {
 296         request->buf = malloc(8); /* 8 needed for the subsequent read */
 297         if(request->buf == NULL) {
 298             close(request->fd);
 299             request->fd = -1;
 300             request->handler(-ENOMEM, request);
 301             destroySocksRequest(request);
 302             return 1;
 303         }
 304
 305         request->buf[0] = 5;             /* ver */
 306         request->buf[1] = 1;             /* nmethods */
 307         request->buf[2] = 0;             /* no authentication required */
 308         do_stream(IO_WRITE, request->fd, 0, request->buf, 3,
 309                   socksWriteHandler, request);
 310     } else {
 311         request->handler(-EUNKNOWN, request);
 312     }
 313     return 1;
 314 }
 315
 316 static int
 317 socksWriteHandler(int status,
 318                   FdEventHandlerPtr event,
 319                   StreamRequestPtr srequest)
 320 {
 321     SocksRequestPtr request = srequest->data;
 322
 323     if(status < 0)
 324         goto error;
 325
 326     if(!streamRequestDone(srequest)) {
 327         if(status) {
 328             status = -ESOCKS_PROTOCOL;
 329             goto error;
 330         }
 331         return 0;
 332     }
 333
 334     do_stream(IO_READ | IO_NOTNOW, request->fd, 0, request->buf, 8,
 335               socksProxyType == aSocks5 ?
 336               socks5ReadHandler : socksReadHandler,
 337               request);
 338     return 1;
 339
 340  error:
 341     close(request->fd);
 342     request->fd = -1;
 343     request->handler(status, request);
 344     destroySocksRequest(request);
 345     return 1;
 346 }
 347
 348 static int
 349 socksReadHandler(int status,
 350                  FdEventHandlerPtr event,
 351                  StreamRequestPtr srequest)
 352 {
 353     SocksRequestPtr request = srequest->data;
 354
 355     if(status < 0)
 356         goto error;
 357
 358     if(srequest->offset < 8) {
 359         if(status) {
 360             status = -ESOCKS_PROTOCOL;
 361             goto error;
 362         }
 363         return 0;
 364     }
 365
 366     if(request->buf[0] != 0 || request->buf[1] != 90) {
 367         if(request->buf[1] >= 91 && request->buf[1] <= 93)
 368             status = -(ESOCKS_PROTOCOL + request->buf[1] - 90);
 369         else
 370             status = -ESOCKS_PROTOCOL;
 371         goto error;
 372     }
 373
 374     request->handler(1, request);
 375     destroySocksRequest(request);
 376     return 1;
 377
 378  error:
 379     close(request->fd);
 380     request->fd = -1;
 381     request->handler(status, request);
 382     destroySocksRequest(request);
 383     return 1;
 384 }
 385
 386 static int
 387 socks5ReadHandler(int status,
 388                   FdEventHandlerPtr event,
 389                   StreamRequestPtr srequest)
 390 {
 391     SocksRequestPtr request = srequest->data;
 392
 393     if(status < 0)
 394         goto error;
 395
 396     if(srequest->offset < 2) {
 397         if(status) {
 398             status = -ESOCKS_PROTOCOL;
 399             goto error;
 400         }
 401         return 0;
 402     }
 403
 404     if(request->buf[0] != 5 || request->buf[1] != 0) {
 405         status = -ESOCKS_PROTOCOL;
 406         goto error;
 407     }
 408
 409     free(request->buf);
 410     request->buf = malloc(5 + request->name->length + 2);
 411     if(request->buf == NULL) {
 412         status = -ENOMEM;
 413         goto error;
 414     }
 415
 416     request->buf[0] = 5;        /* ver */
 417     request->buf[1] = 1;        /* cmd */
 418     request->buf[2] = 0;        /* rsv */
 419     request->buf[3] = 3;        /* atyp */
 420     request->buf[4] = request->name->length;
 421     memcpy(request->buf + 5, request->name->string, request->name->length);
 422     request->buf[5 + request->name->length] = (request->port >> 8) & 0xFF;
 423     request->buf[5 + request->name->length + 1] = request->port & 0xFF;
 424
 425     do_stream(IO_WRITE, request->fd, 0,
 426               request->buf, 5 + request->name->length + 2,
 427               socks5WriteHandler, request);
 428     return 1;
 429
 430  error:
 431     close(request->fd);
 432     request->fd = -1;
 433     request->handler(status, request);
 434     destroySocksRequest(request);
 435     return 1;
 436 }
 437
 438 static int
 439 socks5WriteHandler(int status,
 440                    FdEventHandlerPtr event,
 441                    StreamRequestPtr srequest)
 442 {
 443     SocksRequestPtr request = srequest->data;
 444
 445     if(status < 0)
 446         goto error;
 447
 448     if(!streamRequestDone(srequest)) {
 449         if(status) {
 450             status = -ESOCKS_PROTOCOL;
 451             goto error;
 452         }
 453         return 0;
 454     }
 455
 456     do_stream(IO_READ | IO_NOTNOW, request->fd, 0, request->buf, 10,
 457               socks5ReadHandler2, request);
 458     return 1;
 459
 460  error:
 461     request->handler(status, request);
 462     destroySocksRequest(request);
 463     return 1;
 464 }
 465
 466 static int
 467 socks5ReadHandler2(int status,
 468                    FdEventHandlerPtr event,
 469                    StreamRequestPtr srequest)
 470 {
 471     SocksRequestPtr request = srequest->data;
 472
 473     if(status < 0)
 474         goto error;
 475
 476     if(srequest->offset < 4) {
 477         if(status) {
 478             status = -ESOCKS_PROTOCOL;
 479             goto error;
 480         }
 481         return 0;
 482     }
 483
 484     if(request->buf[0] != 5) {
 485         status = -ESOCKS_PROTOCOL;
 486         goto error;
 487     }
 488
 489     if(request->buf[1] != 0) {
 490         status = -(ESOCKS5_BASE + request->buf[1]);
 491         goto error;
 492     }
 493
 494     if(request->buf[3] != 1) {
 495         status = -ESOCKS_PROTOCOL;
 496         goto error;
 497     }
 498
 499     if(srequest->offset < 10)
 500         return 0;
 501
 502     request->handler(1, request);
 503     destroySocksRequest(request);
 504     return 1;
 505
 506  error:
 507     close(request->fd);
 508     request->fd = -1;
 509     request->handler(status, request);
 510     destroySocksRequest(request);
 511     return 1;
 512 }
 513
 514 #endif