summaryrefslogtreecommitdiff
path: root/gio/gsocks4aproxy.c
blob: 3dad118eb784f873d56b17c201b057b497068449 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
 /* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright (C) 2010 Collabora, Ltd.
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 * Author: Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>
 */

#include "config.h"

#include "gsocks4aproxy.h"

#include <string.h>

#include "giomodule.h"
#include "giomodule-priv.h"
#include "giostream.h"
#include "ginetaddress.h"
#include "ginputstream.h"
#include "glibintl.h"
#include "goutputstream.h"
#include "gproxy.h"
#include "gproxyaddress.h"
#include "gtask.h"

#define SOCKS4_VERSION		  4

#define SOCKS4_CMD_CONNECT	  1
#define SOCKS4_CMD_BIND		  2

#define SOCKS4_MAX_LEN		  255

#define SOCKS4_REP_VERSION	  0
#define SOCKS4_REP_GRANTED	  90
#define SOCKS4_REP_REJECTED       91
#define SOCKS4_REP_NO_IDENT       92
#define SOCKS4_REP_BAD_IDENT      93

static void g_socks4a_proxy_iface_init (GProxyInterface *proxy_iface);

#define g_socks4a_proxy_get_type _g_socks4a_proxy_get_type
G_DEFINE_TYPE_WITH_CODE (GSocks4aProxy, g_socks4a_proxy, G_TYPE_OBJECT,
			 G_IMPLEMENT_INTERFACE (G_TYPE_PROXY,
						g_socks4a_proxy_iface_init)
			 _g_io_modules_ensure_extension_points_registered ();
			 g_io_extension_point_implement (G_PROXY_EXTENSION_POINT_NAME,
							 g_define_type_id,
							 "socks4a",
							 0))

static void
g_socks4a_proxy_finalize (GObject *object)
{
  /* must chain up */
  G_OBJECT_CLASS (g_socks4a_proxy_parent_class)->finalize (object);
}

static void
g_socks4a_proxy_init (GSocks4aProxy *proxy)
{
  proxy->supports_hostname = TRUE;
}

/*                                                             |-> SOCKSv4a only
 * +----+----+----+----+----+----+----+----+----+----+....+----+------+....+------+
 * | VN | CD | DSTPORT |      DSTIP        | USERID       |NULL| HOST |    | NULL |
 * +----+----+----+----+----+----+----+----+----+----+....+----+------+....+------+
 *    1    1      2              4           variable       1    variable
 */
#define SOCKS4_CONN_MSG_LEN	    (9 + SOCKS4_MAX_LEN * 2)
static gint
set_connect_msg (guint8      *msg,
		 const gchar *hostname,
		 guint16      port,
		 const char  *username,
		 GError     **error)
{
  GInetAddress *addr;
  guint len = 0;
  gsize addr_len;
  gboolean is_ip;
  const gchar *ip;

  msg[len++] = SOCKS4_VERSION;
  msg[len++] = SOCKS4_CMD_CONNECT;

    {
      guint16 hp = g_htons (port);
      memcpy (msg + len, &hp, 2);
      len += 2;
    }

  is_ip = g_hostname_is_ip_address (hostname);

  if (is_ip)
    ip = hostname;
  else
    ip = "0.0.0.1";
    
  addr = g_inet_address_new_from_string (ip);
  addr_len = g_inet_address_get_native_size (addr);

  if (addr_len != 4)
    {
      g_set_error (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
		  _("SOCKSv4 does not support IPv6 address “%s”"),
		  ip);
      g_object_unref (addr);
      return -1;
    }

  memcpy (msg + len, g_inet_address_to_bytes (addr), addr_len);
  len += addr_len;

  g_object_unref (addr);

  if (username)
    {
      gsize user_len = strlen (username);

      if (user_len > SOCKS4_MAX_LEN)
	{
	  g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
			       _("Username is too long for SOCKSv4 protocol"));
	  return -1;
	}

      memcpy (msg + len, username, user_len);
      len += user_len;
    }

  msg[len++] = '\0';

  if (!is_ip)
    {
      gsize host_len = strlen (hostname);

      if (host_len > SOCKS4_MAX_LEN)
	{
	  g_set_error (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
		       _("Hostname “%s” is too long for SOCKSv4 protocol"),
		       hostname);
	  return -1;
	}

      memcpy (msg + len, hostname, host_len);
      len += host_len;
      msg[len++] = '\0';
    }

  return len;
}

/*
 * +----+----+----+----+----+----+----+----+
 * | VN | CD | DSTPORT |      DSTIP        |
 * +----+----+----+----+----+----+----+----+
 *    1    1      2              4
 */
#define SOCKS4_CONN_REP_LEN	  8
static gboolean
parse_connect_reply (const guint8 *data, GError **error)
{
  if (data[0] != SOCKS4_REP_VERSION)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
			   _("The server is not a SOCKSv4 proxy server."));
      return FALSE;
    }

  if (data[1] != SOCKS4_REP_GRANTED)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
			   _("Connection through SOCKSv4 server was rejected"));
      return FALSE;
    }

  return TRUE;
}

static GIOStream *
g_socks4a_proxy_connect (GProxy            *proxy,
			 GIOStream         *io_stream,
			 GProxyAddress     *proxy_address,
			 GCancellable      *cancellable,
			 GError           **error)
{
  GInputStream *in;
  GOutputStream *out;
  const gchar *hostname;
  guint16 port;
  const gchar *username;

  hostname = g_proxy_address_get_destination_hostname (proxy_address);
  port = g_proxy_address_get_destination_port (proxy_address);
  username = g_proxy_address_get_username (proxy_address);

  in = g_io_stream_get_input_stream (io_stream);
  out = g_io_stream_get_output_stream (io_stream);

  /* Send SOCKS4 connection request */
    {
      guint8 msg[SOCKS4_CONN_MSG_LEN];
      gint len;
      
      len = set_connect_msg (msg, hostname, port, username, error);

      if (len < 0)
	goto error;

      if (!g_output_stream_write_all (out, msg, len, NULL,
				      cancellable, error))
	goto error;
    }

  /* Read SOCKS4 response */
    {
      guint8 data[SOCKS4_CONN_REP_LEN];

      if (!g_input_stream_read_all (in, data, SOCKS4_CONN_REP_LEN, NULL,
				    cancellable, error))
	goto error;

      if (!parse_connect_reply (data, error))
	goto error;
    }

  return g_object_ref (io_stream);

error:
  return NULL;
}


typedef struct
{
  GIOStream *io_stream;

  /* For connecting */
  guint8 *buffer;
  gssize length;
  gssize offset;

} ConnectAsyncData;

static void connect_msg_write_cb      (GObject          *source,
				       GAsyncResult     *result,
				       gpointer          user_data);
static void connect_reply_read_cb     (GObject          *source,
				       GAsyncResult     *result,
				       gpointer          user_data);

static void
free_connect_data (ConnectAsyncData *data)
{
  g_object_unref (data->io_stream);
  g_slice_free (ConnectAsyncData, data);
}

static void
do_read (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
{
   GInputStream *in;
   in = g_io_stream_get_input_stream (data->io_stream);
   g_input_stream_read_async (in,
			      data->buffer + data->offset,
			      data->length - data->offset,
			      g_task_get_priority (task),
			      g_task_get_cancellable (task),
			      callback, task);
}

static void
do_write (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
{
  GOutputStream *out;
  out = g_io_stream_get_output_stream (data->io_stream);
  g_output_stream_write_async (out,
			       data->buffer + data->offset,
			       data->length - data->offset,
			       g_task_get_priority (task),
			       g_task_get_cancellable (task),
			       callback, task);
}



static void
g_socks4a_proxy_connect_async (GProxy               *proxy,
			       GIOStream            *io_stream,
			       GProxyAddress        *proxy_address,
			       GCancellable         *cancellable,
			       GAsyncReadyCallback   callback,
			       gpointer              user_data)
{
  GError *error = NULL;
  GTask *task;
  ConnectAsyncData *data;
  const gchar *hostname;
  guint16 port;
  const gchar *username;

  data = g_slice_new0 (ConnectAsyncData);
  data->io_stream = g_object_ref (io_stream);

  task = g_task_new (proxy, cancellable, callback, user_data);
  g_task_set_source_tag (task, g_socks4a_proxy_connect_async);
  g_task_set_task_data (task, data, (GDestroyNotify) free_connect_data);

  hostname = g_proxy_address_get_destination_hostname (proxy_address);
  port = g_proxy_address_get_destination_port (proxy_address);
  username = g_proxy_address_get_username (proxy_address); 

  data->buffer = g_malloc0 (SOCKS4_CONN_MSG_LEN);
  data->length = set_connect_msg (data->buffer,
				  hostname, port, username,
				  &error);
  data->offset = 0;

  if (data->length < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
    }
  else
    {
      do_write (connect_msg_write_cb, task, data);
    }
}

static void
connect_msg_write_cb (GObject      *source,
		      GAsyncResult *result,
		      gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize written;

  written = g_output_stream_write_finish (G_OUTPUT_STREAM (source),
					  result, &error);
  
  if (written < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += written;

  if (data->offset == data->length)
    {
      g_free (data->buffer);

      data->buffer = g_malloc0 (SOCKS4_CONN_REP_LEN);
      data->length = SOCKS4_CONN_REP_LEN;
      data->offset = 0;

      do_read (connect_reply_read_cb, task, data);
    }
  else
    {
      do_write (connect_msg_write_cb, task, data);
    }
}

static void
connect_reply_read_cb (GObject       *source,
		       GAsyncResult  *result,
		       gpointer       user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
				     result, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += read;

  if (data->offset == data->length)
    {
      if (!parse_connect_reply (data->buffer, &error))
	{
	  g_task_return_error (task, error);
	  g_object_unref (task);
	  return;
	}
      else
	{
	  g_task_return_pointer (task, g_object_ref (data->io_stream), g_object_unref);
	  g_object_unref (task);
	  return;
	}
    }
  else
    {
      do_read (connect_reply_read_cb, task, data);
    }
}

static GIOStream *g_socks4a_proxy_connect_finish (GProxy       *proxy,
						  GAsyncResult *result,
						  GError      **error);

static GIOStream *
g_socks4a_proxy_connect_finish (GProxy       *proxy,
			        GAsyncResult *result,
			        GError      **error)
{
  return g_task_propagate_pointer (G_TASK (result), error);
}

static gboolean
g_socks4a_proxy_supports_hostname (GProxy *proxy)
{
  return G_SOCKS4A_PROXY (proxy)->supports_hostname;
}

static void
g_socks4a_proxy_class_init (GSocks4aProxyClass *class)
{
  GObjectClass *object_class;

  object_class = (GObjectClass *) class;
  object_class->finalize = g_socks4a_proxy_finalize;
}

static void
g_socks4a_proxy_iface_init (GProxyInterface *proxy_iface)
{
  proxy_iface->connect  = g_socks4a_proxy_connect;
  proxy_iface->connect_async = g_socks4a_proxy_connect_async;
  proxy_iface->connect_finish = g_socks4a_proxy_connect_finish;
  proxy_iface->supports_hostname = g_socks4a_proxy_supports_hostname;
}