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
g_socks4a_proxy_finalize(GObject * object)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
g_socks4a_proxy_init(GSocks4aProxy * proxy)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
set_connect_msg(guint8 * msg,const gchar * hostname,guint16 port,const char * username,GError ** error)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
parse_connect_reply(const guint8 * data,GError ** error)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 *
g_socks4a_proxy_connect(GProxy * proxy,GIOStream * io_stream,GProxyAddress * proxy_address,GCancellable * cancellable,GError ** error)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
free_connect_data(ConnectAsyncData * data)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
do_read(GAsyncReadyCallback callback,GTask * task,ConnectAsyncData * data)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
do_write(GAsyncReadyCallback callback,GTask * task,ConnectAsyncData * data)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
g_socks4a_proxy_connect_async(GProxy * proxy,GIOStream * io_stream,GProxyAddress * proxy_address,GCancellable * cancellable,GAsyncReadyCallback callback,gpointer user_data)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
connect_msg_write_cb(GObject * source,GAsyncResult * result,gpointer user_data)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
connect_reply_read_cb(GObject * source,GAsyncResult * result,gpointer user_data)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 *
g_socks4a_proxy_connect_finish(GProxy * proxy,GAsyncResult * result,GError ** error)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
g_socks4a_proxy_supports_hostname(GProxy * proxy)437 g_socks4a_proxy_supports_hostname (GProxy *proxy)
438 {
439 return G_SOCKS4A_PROXY (proxy)->supports_hostname;
440 }
441
442 static void
g_socks4a_proxy_class_init(GSocks4aProxyClass * class)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
g_socks4a_proxy_iface_init(GProxyInterface * proxy_iface)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 }
459