gio/gsocks4aproxy.c

   1  /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2010 Collabora, Ltd.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library 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 GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>
  19  */
  20
  21 #include "config.h"
  22
  23 #include "gsocks4aproxy.h"
  24
  25 #include <string.h>
  26
  27 #include "giomodule.h"
  28 #include "giomodule-priv.h"
  29 #include "giostream.h"
  30 #include "ginetaddress.h"
  31 #include "ginputstream.h"
  32 #include "glibintl.h"
  33 #include "goutputstream.h"
  34 #include "gproxy.h"
  35 #include "gproxyaddress.h"
  36 #include "gtask.h"
  37
  38 #define SOCKS4_VERSION            4
  39
  40 #define SOCKS4_CMD_CONNECT        1
  41 #define SOCKS4_CMD_BIND           2
  42
  43 #define SOCKS4_MAX_LEN            255
  44
  45 #define SOCKS4_REP_VERSION        0
  46 #define SOCKS4_REP_GRANTED        90
  47 #define SOCKS4_REP_REJECTED       91
  48 #define SOCKS4_REP_NO_IDENT       92
  49 #define SOCKS4_REP_BAD_IDENT      93
  50
  51 static void g_socks4a_proxy_iface_init (GProxyInterface *proxy_iface);
  52
  53 #define g_socks4a_proxy_get_type _g_socks4a_proxy_get_type
  54 G_DEFINE_TYPE_WITH_CODE (GSocks4aProxy, g_socks4a_proxy, G_TYPE_OBJECT,
  55                          G_IMPLEMENT_INTERFACE (G_TYPE_PROXY,
  56                                                 g_socks4a_proxy_iface_init)
  57                          _g_io_modules_ensure_extension_points_registered ();
  58                          g_io_extension_point_implement (G_PROXY_EXTENSION_POINT_NAME,
  59                                                          g_define_type_id,
  60                                                          "socks4a",
  61                                                          0))
  62
  63 static void
  64 g_socks4a_proxy_finalize (GObject *object)
  65 {
  66   /* must chain up */
  67   G_OBJECT_CLASS (g_socks4a_proxy_parent_class)->finalize (object);
  68 }
  69
  70 static void
  71 g_socks4a_proxy_init (GSocks4aProxy *proxy)
  72 {
  73   proxy->supports_hostname = TRUE;
  74 }
  75
  76 /*                                                             |-> SOCKSv4a only
  77  * +----+----+----+----+----+----+----+----+----+----+....+----+------+....+------+
  78  * | VN | CD | DSTPORT |      DSTIP        | USERID       |NULL| HOST |    | NULL |
  79  * +----+----+----+----+----+----+----+----+----+----+....+----+------+....+------+
  80  *    1    1      2              4           variable       1    variable
  81  */
  82 #define SOCKS4_CONN_MSG_LEN         (9 + SOCKS4_MAX_LEN * 2)
  83 static gint
  84 set_connect_msg (guint8      *msg,
  85                  const gchar *hostname,
  86                  guint16      port,
  87                  const char  *username,
  88                  GError     **error)
  89 {
  90   GInetAddress *addr;
  91   guint len = 0;
  92   gsize addr_len;
  93   gboolean is_ip;
  94   const gchar *ip;
  95
  96   msg[len++] = SOCKS4_VERSION;
  97   msg[len++] = SOCKS4_CMD_CONNECT;
  98
  99     {
 100       guint16 hp = g_htons (port);
 101       memcpy (msg + len, &hp, 2);
 102       len += 2;
 103     }
 104
 105   is_ip = g_hostname_is_ip_address (hostname);
 106
 107   if (is_ip)
 108     ip = hostname;
 109   else
 110     ip = "0.0.0.1";
 111
 112   addr = g_inet_address_new_from_string (ip);
 113   addr_len = g_inet_address_get_native_size (addr);
 114
 115   if (addr_len != 4)
 116     {
 117       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
 118                   _("SOCKSv4 does not support IPv6 address “%s”"),
 119                   ip);
 120       g_object_unref (addr);
 121       return -1;
 122     }
 123
 124   memcpy (msg + len, g_inet_address_to_bytes (addr), addr_len);
 125   len += addr_len;
 126
 127   g_object_unref (addr);
 128
 129   if (username)
 130     {
 131       gsize user_len = strlen (username);
 132
 133       if (user_len > SOCKS4_MAX_LEN)
 134         {
 135           g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
 136                                _("Username is too long for SOCKSv4 protocol"));
 137           return -1;
 138         }
 139
 140       memcpy (msg + len, username, user_len);
 141       len += user_len;
 142     }
 143
 144   msg[len++] = '\0';
 145
 146   if (!is_ip)
 147     {
 148       gsize host_len = strlen (hostname);
 149
 150       if (host_len > SOCKS4_MAX_LEN)
 151         {
 152           g_set_error (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
 153                        _("Hostname “%s” is too long for SOCKSv4 protocol"),
 154                        hostname);
 155           return -1;
 156         }
 157
 158       memcpy (msg + len, hostname, host_len);
 159       len += host_len;
 160       msg[len++] = '\0';
 161     }
 162
 163   return len;
 164 }
 165
 166 /*
 167  * +----+----+----+----+----+----+----+----+
 168  * | VN | CD | DSTPORT |      DSTIP        |
 169  * +----+----+----+----+----+----+----+----+
 170  *    1    1      2              4
 171  */
 172 #define SOCKS4_CONN_REP_LEN       8
 173 static gboolean
 174 parse_connect_reply (const guint8 *data, GError **error)
 175 {
 176   if (data[0] != SOCKS4_REP_VERSION)
 177     {
 178       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
 179                            _("The server is not a SOCKSv4 proxy server."));
 180       return FALSE;
 181     }
 182
 183   if (data[1] != SOCKS4_REP_GRANTED)
 184     {
 185       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
 186                            _("Connection through SOCKSv4 server was rejected"));
 187       return FALSE;
 188     }
 189
 190   return TRUE;
 191 }
 192
 193 static GIOStream *
 194 g_socks4a_proxy_connect (GProxy            *proxy,
 195                          GIOStream         *io_stream,
 196                          GProxyAddress     *proxy_address,
 197                          GCancellable      *cancellable,
 198                          GError           **error)
 199 {
 200   GInputStream *in;
 201   GOutputStream *out;
 202   const gchar *hostname;
 203   guint16 port;
 204   const gchar *username;
 205
 206   hostname = g_proxy_address_get_destination_hostname (proxy_address);
 207   port = g_proxy_address_get_destination_port (proxy_address);
 208   username = g_proxy_address_get_username (proxy_address);
 209
 210   in = g_io_stream_get_input_stream (io_stream);
 211   out = g_io_stream_get_output_stream (io_stream);
 212
 213   /* Send SOCKS4 connection request */
 214     {
 215       guint8 msg[SOCKS4_CONN_MSG_LEN];
 216       gint len;
 217
 218       len = set_connect_msg (msg, hostname, port, username, error);
 219
 220       if (len < 0)
 221         goto error;
 222
 223       if (!g_output_stream_write_all (out, msg, len, NULL,
 224                                       cancellable, error))
 225         goto error;
 226     }
 227
 228   /* Read SOCKS4 response */
 229     {
 230       guint8 data[SOCKS4_CONN_REP_LEN];
 231
 232       if (!g_input_stream_read_all (in, data, SOCKS4_CONN_REP_LEN, NULL,
 233                                     cancellable, error))
 234         goto error;
 235
 236       if (!parse_connect_reply (data, error))
 237         goto error;
 238     }
 239
 240   return g_object_ref (io_stream);
 241
 242 error:
 243   return NULL;
 244 }
 245
 246
 247 typedef struct
 248 {
 249   GIOStream *io_stream;
 250
 251   /* For connecting */
 252   guint8 *buffer;
 253   gssize length;
 254   gssize offset;
 255
 256 } ConnectAsyncData;
 257
 258 static void connect_msg_write_cb      (GObject          *source,
 259                                        GAsyncResult     *result,
 260                                        gpointer          user_data);
 261 static void connect_reply_read_cb     (GObject          *source,
 262                                        GAsyncResult     *result,
 263                                        gpointer          user_data);
 264
 265 static void
 266 free_connect_data (ConnectAsyncData *data)
 267 {
 268   g_object_unref (data->io_stream);
 269   g_slice_free (ConnectAsyncData, data);
 270 }
 271
 272 static void
 273 do_read (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
 274 {
 275    GInputStream *in;
 276    in = g_io_stream_get_input_stream (data->io_stream);
 277    g_input_stream_read_async (in,
 278                               data->buffer + data->offset,
 279                               data->length - data->offset,
 280                               g_task_get_priority (task),
 281                               g_task_get_cancellable (task),
 282                               callback, task);
 283 }
 284
 285 static void
 286 do_write (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
 287 {
 288   GOutputStream *out;
 289   out = g_io_stream_get_output_stream (data->io_stream);
 290   g_output_stream_write_async (out,
 291                                data->buffer + data->offset,
 292                                data->length - data->offset,
 293                                g_task_get_priority (task),
 294                                g_task_get_cancellable (task),
 295                                callback, task);
 296 }
 297
 298
 299
 300 static void
 301 g_socks4a_proxy_connect_async (GProxy               *proxy,
 302                                GIOStream            *io_stream,
 303                                GProxyAddress        *proxy_address,
 304                                GCancellable         *cancellable,
 305                                GAsyncReadyCallback   callback,
 306                                gpointer              user_data)
 307 {
 308   GError *error = NULL;
 309   GTask *task;
 310   ConnectAsyncData *data;
 311   const gchar *hostname;
 312   guint16 port;
 313   const gchar *username;
 314
 315   data = g_slice_new0 (ConnectAsyncData);
 316   data->io_stream = g_object_ref (io_stream);
 317
 318   task = g_task_new (proxy, cancellable, callback, user_data);
 319   g_task_set_source_tag (task, g_socks4a_proxy_connect_async);
 320   g_task_set_task_data (task, data, (GDestroyNotify) free_connect_data);
 321
 322   hostname = g_proxy_address_get_destination_hostname (proxy_address);
 323   port = g_proxy_address_get_destination_port (proxy_address);
 324   username = g_proxy_address_get_username (proxy_address);
 325
 326   data->buffer = g_malloc0 (SOCKS4_CONN_MSG_LEN);
 327   data->length = set_connect_msg (data->buffer,
 328                                   hostname, port, username,
 329                                   &error);
 330   data->offset = 0;
 331
 332   if (data->length < 0)
 333     {
 334       g_task_return_error (task, error);
 335       g_object_unref (task);
 336     }
 337   else
 338     {
 339       do_write (connect_msg_write_cb, task, data);
 340     }
 341 }
 342
 343 static void
 344 connect_msg_write_cb (GObject      *source,
 345                       GAsyncResult *result,
 346                       gpointer      user_data)
 347 {
 348   GTask *task = user_data;
 349   ConnectAsyncData *data = g_task_get_task_data (task);
 350   GError *error = NULL;
 351   gssize written;
 352
 353   written = g_output_stream_write_finish (G_OUTPUT_STREAM (source),
 354                                           result, &error);
 355
 356   if (written < 0)
 357     {
 358       g_task_return_error (task, error);
 359       g_object_unref (task);
 360       return;
 361     }
 362
 363   data->offset += written;
 364
 365   if (data->offset == data->length)
 366     {
 367       g_free (data->buffer);
 368
 369       data->buffer = g_malloc0 (SOCKS4_CONN_REP_LEN);
 370       data->length = SOCKS4_CONN_REP_LEN;
 371       data->offset = 0;
 372
 373       do_read (connect_reply_read_cb, task, data);
 374     }
 375   else
 376     {
 377       do_write (connect_msg_write_cb, task, data);
 378     }
 379 }
 380
 381 static void
 382 connect_reply_read_cb (GObject       *source,
 383                        GAsyncResult  *result,
 384                        gpointer       user_data)
 385 {
 386   GTask *task = user_data;
 387   ConnectAsyncData *data = g_task_get_task_data (task);
 388   GError *error = NULL;
 389   gssize read;
 390
 391   read = g_input_stream_read_finish (G_INPUT_STREAM (source),
 392                                      result, &error);
 393
 394   if (read < 0)
 395     {
 396       g_task_return_error (task, error);
 397       g_object_unref (task);
 398       return;
 399     }
 400
 401   data->offset += read;
 402
 403   if (data->offset == data->length)
 404     {
 405       if (!parse_connect_reply (data->buffer, &error))
 406         {
 407           g_task_return_error (task, error);
 408           g_object_unref (task);
 409           return;
 410         }
 411       else
 412         {
 413           g_task_return_pointer (task, g_object_ref (data->io_stream), g_object_unref);
 414           g_object_unref (task);
 415           return;
 416         }
 417     }
 418   else
 419     {
 420       do_read (connect_reply_read_cb, task, data);
 421     }
 422 }
 423
 424 static GIOStream *g_socks4a_proxy_connect_finish (GProxy       *proxy,
 425                                                   GAsyncResult *result,
 426                                                   GError      **error);
 427
 428 static GIOStream *
 429 g_socks4a_proxy_connect_finish (GProxy       *proxy,
 430                                 GAsyncResult *result,
 431                                 GError      **error)
 432 {
 433   return g_task_propagate_pointer (G_TASK (result), error);
 434 }
 435
 436 static gboolean
 437 g_socks4a_proxy_supports_hostname (GProxy *proxy)
 438 {
 439   return G_SOCKS4A_PROXY (proxy)->supports_hostname;
 440 }
 441
 442 static void
 443 g_socks4a_proxy_class_init (GSocks4aProxyClass *class)
 444 {
 445   GObjectClass *object_class;
 446
 447   object_class = (GObjectClass *) class;
 448   object_class->finalize = g_socks4a_proxy_finalize;
 449 }
 450
 451 static void
 452 g_socks4a_proxy_iface_init (GProxyInterface *proxy_iface)
 453 {
 454   proxy_iface->connect  = g_socks4a_proxy_connect;
 455   proxy_iface->connect_async = g_socks4a_proxy_connect_async;
 456   proxy_iface->connect_finish = g_socks4a_proxy_connect_finish;
 457   proxy_iface->supports_hostname = g_socks4a_proxy_supports_hostname;
 458 }