summaryrefslogtreecommitdiff
path: root/source3/utils/smbfilter.c
blob: f455f2df91c8c8775a24231ca025cc62a0863ef1 (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
/* 
   Unix SMB/CIFS implementation.
   SMB filter/socket plugin
   Copyright (C) Andrew Tridgell 1999

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "system/select.h"
#include "../lib/util/select.h"

#define SECURITY_MASK 0
#define SECURITY_SET  0

/* this forces non-unicode */
#define CAPABILITY_MASK 0
#define CAPABILITY_SET  0

/* and non-unicode for the client too */
#define CLI_CAPABILITY_MASK 0
#define CLI_CAPABILITY_SET  0

static char *netbiosname;
static char packet[BUFFER_SIZE];

static void save_file(const char *fname, void *ppacket, size_t length)
{
	int fd;
	fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644);
	if (fd == -1) {
		perror(fname);
		return;
	}
	if (write(fd, ppacket, length) != length) {
		fprintf(stderr,"Failed to write %s\n", fname);
		close(fd);
		return;
	}
	close(fd);
	printf("Wrote %ld bytes to %s\n", (unsigned long)length, fname);
}

static void filter_reply(char *buf)
{
	int msg_type = CVAL(buf,0);
	int type = CVAL(buf,smb_com);
	unsigned x;

	if (msg_type) return;

	switch (type) {

	case SMBnegprot:
		/* force the security bits */
		x = CVAL(buf, smb_vwv1);
		x = (x | SECURITY_SET) & ~SECURITY_MASK;
		SCVAL(buf, smb_vwv1, x);

		/* force the capabilities */
		x = IVAL(buf,smb_vwv9+1);
		x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
		SIVAL(buf, smb_vwv9+1, x);
		break;

	}
}

static void filter_request(char *buf, size_t buf_len)
{
	int msg_type = CVAL(buf,0);
	int type = CVAL(buf,smb_com);
	unsigned x;
	fstring name1,name2;
	int name_len1, name_len2;
	int name_type1, name_type2;

	if (msg_type) {
		/* it's a netbios special */
		switch (msg_type)
		case 0x81:
			/* session request */
			/* inbuf_size is guaranteed to be at least 4. */
			name_len1 = name_len((unsigned char *)(buf+4),
					buf_len - 4);
			if (name_len1 <= 0 || name_len1 > buf_len - 4) {
				DEBUG(0,("Invalid name length in session request\n"));
				return;
			}
			name_len2 = name_len((unsigned char *)(buf+4+name_len1),
					buf_len - 4 - name_len1);
			if (name_len2 <= 0 || name_len2 > buf_len - 4 - name_len1) {
				DEBUG(0,("Invalid name length in session request\n"));
				return;
			}

			name_type1 = name_extract((unsigned char *)buf,
					buf_len,(unsigned int)4,name1);
			name_type2 = name_extract((unsigned char *)buf,
					buf_len,(unsigned int)(4 + name_len1),name2);

			if (name_type1 == -1 || name_type2 == -1) {
				DEBUG(0,("Invalid name type in session request\n"));
				return;
			}

			d_printf("sesion_request: %s -> %s\n",
				 name1, name2);
			if (netbiosname) {
				char *mangled = name_mangle(
					talloc_tos(), netbiosname, 0x20);
				if (mangled != NULL) {
					/* replace the destination netbios
					 * name */
					memcpy(buf+4, mangled,
					       name_len((unsigned char *)mangled,
							talloc_get_size(mangled)));
					TALLOC_FREE(mangled);
				}
			}
		return;
	}

	/* it's an ordinary SMB request */
	switch (type) {
	case SMBsesssetupX:
		/* force the client capabilities */
		x = IVAL(buf,smb_vwv11);
		d_printf("SMBsesssetupX cap=0x%08x\n", x);
		d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
		system("mv sessionsetup.dat sessionsetup1.dat");
		save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
		x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
		SIVAL(buf, smb_vwv11, x);
		break;
	}
}

/****************************************************************************
 Send an smb to a fd.
****************************************************************************/

static bool send_smb(int fd, char *buffer)
{
	size_t len;
	size_t nwritten=0;
	ssize_t ret;

        len = smb_len(buffer) + 4;

	while (nwritten < len) {
		ret = write_data(fd,buffer+nwritten,len - nwritten);
		if (ret <= 0) {
			DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
				(int)len,(int)ret, strerror(errno) ));
			return false;
		}
		nwritten += ret;
	}

	return true;
}

static void filter_child(int c, struct sockaddr_storage *dest_ss)
{
	NTSTATUS status;
	int s = -1;

	/* we have a connection from a new client, now connect to the server */
	status = open_socket_out(dest_ss, 445, LONG_CONNECT_TIMEOUT, &s);

	if (s == -1) {
		char addr[INET6_ADDRSTRLEN];
		if (dest_ss) {
			print_sockaddr(addr, sizeof(addr), dest_ss);
		}

		d_printf("Unable to connect to %s (%s)\n",
			 dest_ss?addr:"NULL",strerror(errno));
		exit(1);
	}

	while (c != -1 || s != -1) {
		struct pollfd fds[2];
		int num_fds, ret;

		memset(fds, 0, sizeof(struct pollfd) * 2);
		fds[0].fd = -1;
		fds[1].fd = -1;
		num_fds = 0;

		if (s != -1) {
			fds[num_fds].fd = s;
			fds[num_fds].events = POLLIN|POLLHUP;
			num_fds += 1;
		}
		if (c != -1) {
			fds[num_fds].fd = c;
			fds[num_fds].events = POLLIN|POLLHUP;
			num_fds += 1;
		}

		ret = sys_poll_intr(fds, num_fds, -1);
		if (ret <= 0) {
			continue;
		}

		/*
		 * find c in fds and see if it's readable
		 */
		if ((c != -1) &&
		    (((fds[0].fd == c)
		      && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
		     ((fds[1].fd == c)
		      && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
			size_t len;
			if (!NT_STATUS_IS_OK(receive_smb_raw(
							c, packet, sizeof(packet),
							0, 0, &len))) {
				d_printf("client closed connection\n");
				exit(0);
			}
			filter_request(packet, len);
			if (!send_smb(s, packet)) {
				d_printf("server is dead\n");
				exit(1);
			}			
		}

		/*
		 * find s in fds and see if it's readable
		 */
		if ((s != -1) &&
		    (((fds[0].fd == s)
		      && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
		     ((fds[1].fd == s)
		      && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
			size_t len;
			if (!NT_STATUS_IS_OK(receive_smb_raw(
							s, packet, sizeof(packet),
							0, 0, &len))) {
				d_printf("server closed connection\n");
				exit(0);
			}
			filter_reply(packet);
			if (!send_smb(c, packet)) {
				d_printf("client is dead\n");
				exit(1);
			}			
		}
	}
	d_printf("Connection closed\n");
	exit(0);
}


static void start_filter(char *desthost)
{
	int s, c;
	struct sockaddr_storage dest_ss;
	struct sockaddr_storage my_ss;

	CatchChild();

	/* start listening on port 445 locally */

	zero_sockaddr(&my_ss);
	s = open_socket_in(SOCK_STREAM, 445, 0, &my_ss, True);

	if (s == -1) {
		d_printf("bind failed\n");
		exit(1);
	}

	if (listen(s, 5) == -1) {
		d_printf("listen failed\n");
	}

	if (!resolve_name(desthost, &dest_ss, 0x20, false)) {
		d_printf("Unable to resolve host %s\n", desthost);
		exit(1);
	}

	while (1) {
		int num, revents;
		struct sockaddr_storage ss;
		socklen_t in_addrlen = sizeof(ss);

		num = poll_intr_one_fd(s, POLLIN|POLLHUP, -1, &revents);
		if ((num > 0) && (revents & (POLLIN|POLLHUP|POLLERR))) {
			c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
			if (c != -1) {
				if (fork() == 0) {
					close(s);
					filter_child(c, &dest_ss);
					exit(0);
				} else {
					close(c);
				}
			}
		}
	}
}


int main(int argc, char *argv[])
{
	char *desthost;
	const char *configfile;
	TALLOC_CTX *frame = talloc_stackframe();

	load_case_tables();

	setup_logging(argv[0], DEBUG_STDOUT);

	configfile = get_dyn_CONFIGFILE();

	if (argc < 2) {
		fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
		exit(1);
	}

	desthost = argv[1];
	if (argc > 2) {
		netbiosname = argv[2];
	}

	if (!lp_load(configfile,True,False,False,True)) {
		d_printf("Unable to load config file\n");
	}

	start_filter(desthost);
	TALLOC_FREE(frame);
	return 0;
}