aboutsummaryrefslogtreecommitdiffstats
path: root/extcap/sshdump.c
blob: e29b5150c83a477724bb450bd8ea2c7448f1743f (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
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
/* sshdump.c
 * sshdump is extcap tool used to capture data using a remote ssh host
 *
 * Copyright 2015, Dario Lombardo
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <extcap/extcap-base.h>
#include <extcap/ssh-base.h>
#include <wsutil/interface.h>
#include <wsutil/file_util.h>
#include <wsutil/strtoi.h>
#include <wsutil/filesystem.h>
#include <wsutil/glib-compat.h>

#include <errno.h>
#include <string.h>
#include <fcntl.h>

#define SSHDUMP_VERSION_MAJOR "1"
#define SSHDUMP_VERSION_MINOR "0"
#define SSHDUMP_VERSION_RELEASE "0"

#define SSH_EXTCAP_INTERFACE "ssh"
#define SSH_READ_BLOCK_SIZE 256

enum {
	EXTCAP_BASE_OPTIONS_ENUM,
	OPT_HELP,
	OPT_VERSION,
	OPT_REMOTE_HOST,
	OPT_REMOTE_PORT,
	OPT_REMOTE_USERNAME,
	OPT_REMOTE_PASSWORD,
	OPT_REMOTE_INTERFACE,
	OPT_REMOTE_CAPTURE_COMMAND,
	OPT_REMOTE_FILTER,
	OPT_SSHKEY,
	OPT_SSHKEY_PASSPHRASE,
	OPT_REMOTE_COUNT,
	OPT_REMOTE_SUDO
};

static struct option longopts[] = {
	EXTCAP_BASE_OPTIONS,
	{ "help", no_argument, NULL, OPT_HELP},
	{ "version", no_argument, NULL, OPT_VERSION},
	SSH_BASE_OPTIONS,
	{ "remote-capture-command", required_argument, NULL, OPT_REMOTE_CAPTURE_COMMAND},
	{ "remote-sudo", required_argument, NULL, OPT_REMOTE_SUDO },
	{ 0, 0, 0, 0}
};

static char* interfaces_list_to_filter(GSList* if_list, const unsigned int remote_port);

static int ssh_loop_read(ssh_channel channel, FILE* fp)
{
	int nbytes;
	int ret = EXIT_SUCCESS;
	char buffer[SSH_READ_BLOCK_SIZE];

	/* read from stdin until data are available */
	while (ssh_channel_is_open(channel) && !ssh_channel_is_eof(channel)) {
		nbytes = ssh_channel_read(channel, buffer, SSH_READ_BLOCK_SIZE, 0);
		if (nbytes < 0) {
			g_warning("Error reading from channel");
			goto end;
		}
		if (nbytes == 0) {
			goto end;
		}
		if (fwrite(buffer, 1, nbytes, fp) != (guint)nbytes) {
			g_warning("Error writing to fifo");
			ret = EXIT_FAILURE;
			goto end;
		}
		fflush(fp);
	}

	/* read loop finished... maybe something wrong happened. Read from stderr */
	while (ssh_channel_is_open(channel) && !ssh_channel_is_eof(channel)) {
		nbytes = ssh_channel_read(channel, buffer, SSH_READ_BLOCK_SIZE, 1);
		if (nbytes < 0) {
			g_warning("Error reading from channel");
			goto end;
		}
		if (fwrite(buffer, 1, nbytes, stderr) != (guint)nbytes) {
			g_warning("Error writing to stderr");
			break;
		}
	}

end:
	if (ssh_channel_send_eof(channel) != SSH_OK) {
		g_warning("Error sending EOF in ssh channel");
		ret = EXIT_FAILURE;
	}
	return ret;
}

static char* local_interfaces_to_filter(const guint16 remote_port)
{
	GSList* interfaces = local_interfaces_to_list();
	char* filter = interfaces_list_to_filter(interfaces, remote_port);
	g_slist_free_full(interfaces, g_free);
	return filter;
}

static ssh_channel run_ssh_command(ssh_session sshs, const char* capture_command, const gboolean use_sudo, const char* iface,
		const char* cfilter, const guint32 count)
{
	gchar* cmdline;
	ssh_channel channel;
	char* quoted_iface = NULL;
	char* quoted_filter = NULL;
	char* count_str = NULL;
	unsigned int remote_port = 22;

	if (!iface)
		iface = "eth0";

	channel = ssh_channel_new(sshs);
	if (!channel) {
		g_warning("Can't create channel");
		return NULL;
	}

	if (ssh_channel_open_session(channel) != SSH_OK) {
		g_warning("Can't open session");
		ssh_channel_free(channel);
		return NULL;
	}

	ssh_options_get_port(sshs, &remote_port);

	/* escape parameters to go save with the shell */
	if (capture_command && *capture_command) {
		cmdline = g_strdup(capture_command);
		g_debug("Remote capture command has disabled other options");
	} else {
		quoted_iface = g_shell_quote(iface);
		quoted_filter = g_shell_quote(cfilter ? cfilter : "");
		if (count > 0)
			count_str = g_strdup_printf("-c %u", count);

		cmdline = g_strdup_printf("%s tcpdump -U -i %s -w - %s %s", use_sudo ? "sudo" : "", quoted_iface,
			count_str ? count_str : "", quoted_filter);
	}

	g_debug("Running: %s", cmdline);
	if (ssh_channel_request_exec(channel, cmdline) != SSH_OK) {
		g_warning("Can't request exec");
		ssh_channel_close(channel);
		ssh_channel_free(channel);
		channel = NULL;
	}

	g_free(quoted_iface);
	g_free(quoted_filter);
	g_free(cmdline);
	g_free(count_str);

	return channel;
}

static int ssh_open_remote_connection(const char* hostname, const unsigned int port, const char* username, const char* password,
	const char* sshkey, const char* sshkey_passphrase, const char* iface, const char* cfilter, const char* capture_command,
	const gboolean use_sudo, const guint32 count, const char* fifo)
{
	ssh_session sshs = NULL;
	ssh_channel channel = NULL;
	FILE* fp = stdout;
	int ret = EXIT_FAILURE;
	char* err_info = NULL;

	if (g_strcmp0(fifo, "-")) {
		/* Open or create the output file */
		fp = fopen(fifo, "wb");
		if (fp == NULL) {
			g_warning("Error creating output file: %s (%s)", fifo, g_strerror(errno));
			return EXIT_FAILURE;
		}
	}

	sshs = create_ssh_connection(hostname, port, username, password, sshkey, sshkey_passphrase, &err_info);

	if (!sshs) {
		g_warning("Error creating connection: %s", err_info);
		goto cleanup;
	}

	channel = run_ssh_command(sshs, capture_command, use_sudo, iface, cfilter, count);

	if (!channel) {
		g_warning("Can't run ssh command");
		goto cleanup;
	}

	/* read from channel and write into fp */
	if (ssh_loop_read(channel, fp) != EXIT_SUCCESS) {
		g_warning("Error in read loop");
		ret = EXIT_FAILURE;
		goto cleanup;
	}

	ret = EXIT_SUCCESS;
cleanup:
	if (err_info)
		g_warning("%s", err_info);
	g_free(err_info);

	/* clean up and exit */
	ssh_cleanup(&sshs, &channel);

	if (g_strcmp0(fifo, "-"))
		fclose(fp);
	return ret;
}

static char* interfaces_list_to_filter(GSList* interfaces, const unsigned int remote_port)
{
	GString* filter = g_string_new(NULL);
	GSList* cur;

	if (!interfaces) {
		g_string_append_printf(filter, "not port %u", remote_port);
	} else {
		g_string_append_printf(filter, "not ((host %s", (char*)interfaces->data);
		cur = g_slist_next(interfaces);
		while (cur) {
			g_string_append_printf(filter, " or host %s", (char*)cur->data);
			cur = g_slist_next(cur);
		}
		g_string_append_printf(filter, ") and port %u)", remote_port);
	}
	return g_string_free(filter, FALSE);
}

static int list_config(char *interface, unsigned int remote_port)
{
	unsigned inc = 0;
	char* ipfilter;

	if (!interface) {
		g_warning("ERROR: No interface specified.");
		return EXIT_FAILURE;
	}

	if (g_strcmp0(interface, SSH_EXTCAP_INTERFACE)) {
		g_warning("ERROR: interface must be %s", SSH_EXTCAP_INTERFACE);
		return EXIT_FAILURE;
	}

	ipfilter = local_interfaces_to_filter(remote_port);

	printf("arg {number=%u}{call=--remote-host}{display=Remote SSH server address}"
		"{type=string}{tooltip=The remote SSH host. It can be both "
		"an IP address or a hostname}{required=true}\n", inc++);
	printf("arg {number=%u}{call=--remote-port}{display=Remote SSH server port}"
		"{type=unsigned}{default=22}{tooltip=The remote SSH host port (1-65535)}"
		"{range=1,65535}\n", inc++);
	printf("arg {number=%u}{call=--remote-username}{display=Remote SSH server username}"
		"{type=string}{default=%s}{tooltip=The remote SSH username. If not provided, "
		"the current user will be used}\n", inc++, g_get_user_name());
	printf("arg {number=%u}{call=--remote-password}{display=Remote SSH server password}"
		"{type=password}{tooltip=The SSH password, used when other methods (SSH agent "
		"or key files) are unavailable.}\n", inc++);
	printf("arg {number=%u}{call=--sshkey}{display=Path to SSH private key}"
		"{type=fileselect}{tooltip=The path on the local filesystem of the private ssh key}\n",
		inc++);
	printf("arg {number=%u}{call=--sshkey-passphrase}{display=SSH key passphrase}"
		"{type=password}{tooltip=Passphrase to unlock the SSH private key}\n",
		inc++);
	printf("arg {number=%u}{call=--remote-interface}{display=Remote interface}"
		"{type=string}{default=eth0}{tooltip=The remote network interface used for capture"
		"}\n", inc++);
	printf("arg {number=%u}{call=--remote-capture-command}{display=Remote capture command}"
		"{type=string}{tooltip=The remote command used to capture}\n", inc++);
	printf("arg {number=%u}{call=--remote-sudo}{display=Use sudo on the remote machine}"
		"{type=boolean}{tooltip=Prepend the capture command with sudo on the remote machine}\n", inc++);
	printf("arg {number=%u}{call=--remote-filter}{display=Remote capture filter}"
		"{type=string}{tooltip=The remote capture filter}", inc++);
	if (ipfilter)
		printf("{default=%s}", ipfilter);
	printf("\n");
	printf("arg {number=%u}{call=--remote-count}{display=Packets to capture}"
		"{type=unsigned}{default=0}{tooltip=The number of remote packets to capture. (Default: inf)}\n",
		inc++);

	extcap_config_debug(&inc);

	g_free(ipfilter);

	return EXIT_SUCCESS;
}

static char* concat_filters(const char* extcap_filter, const char* remote_filter)
{
	if (!extcap_filter && remote_filter)
		return g_strdup(remote_filter);

	if (!remote_filter && extcap_filter)
		return g_strdup(extcap_filter);

	if (!remote_filter && !extcap_filter)
		return NULL;

	return g_strdup_printf("(%s) and (%s)", extcap_filter, remote_filter);
}

int main(int argc, char **argv)
{
	int result;
	int option_idx = 0;
	char* remote_host = NULL;
	guint16 remote_port = 22;
	char* remote_username = NULL;
	char* remote_password = NULL;
	char* remote_interface = NULL;
	char* remote_capture_command = NULL;
	char* sshkey = NULL;
	char* sshkey_passphrase = NULL;
	char* remote_filter = NULL;
	guint32 count = 0;
	int ret = EXIT_FAILURE;
	extcap_parameters * extcap_conf = g_new0(extcap_parameters, 1);
	char* help_url;
	char* help_header = NULL;
	gboolean use_sudo = FALSE;

#ifdef _WIN32
	WSADATA wsaData;

	attach_parent_console();
#endif  /* _WIN32 */

	help_url = data_file_url("sshdump.html");
	extcap_base_set_util_info(extcap_conf, argv[0], SSHDUMP_VERSION_MAJOR, SSHDUMP_VERSION_MINOR,
		SSHDUMP_VERSION_RELEASE, help_url);
	g_free(help_url);
	extcap_base_register_interface(extcap_conf, SSH_EXTCAP_INTERFACE, "SSH remote capture", 147, "Remote capture dependent DLT");

	help_header = g_strdup_printf(
		" %s --extcap-interfaces\n"
		" %s --extcap-interface=%s --extcap-dlts\n"
		" %s --extcap-interface=%s --extcap-config\n"
		" %s --extcap-interface=%s --remote-host myhost --remote-port 22222 "
		"--remote-username myuser --remote-interface eth2 --remote-capture-command 'tcpdump -U -i eth0 -w -' "
		"--fifo=FILENAME --capture\n", argv[0], argv[0], SSH_EXTCAP_INTERFACE, argv[0],
		SSH_EXTCAP_INTERFACE, argv[0], SSH_EXTCAP_INTERFACE);
	extcap_help_add_header(extcap_conf, help_header);
	g_free(help_header);
	extcap_help_add_option(extcap_conf, "--help", "print this help");
	extcap_help_add_option(extcap_conf, "--version", "print the version");
	extcap_help_add_option(extcap_conf, "--remote-host <host>", "the remote SSH host");
	extcap_help_add_option(extcap_conf, "--remote-port <port>", "the remote SSH port (default: 22)");
	extcap_help_add_option(extcap_conf, "--remote-username <username>", "the remote SSH username (default: the current user)");
	extcap_help_add_option(extcap_conf, "--remote-password <password>", "the remote SSH password. If not specified, ssh-agent and ssh-key are used");
	extcap_help_add_option(extcap_conf, "--sshkey <public key path>", "the path of the ssh key");
	extcap_help_add_option(extcap_conf, "--sshkey-passphrase <public key passphrase>", "the passphrase to unlock public ssh");
	extcap_help_add_option(extcap_conf, "--remote-interface <iface>", "the remote capture interface (default: eth0)");
	extcap_help_add_option(extcap_conf, "--remote-capture-command <capture command>", "the remote capture command");
	extcap_help_add_option(extcap_conf, "--remote-sudo yes", "use sudo on the remote machine to capture");
	extcap_help_add_option(extcap_conf, "--remote-filter <filter>", "a filter for remote capture (default: don't "
		"listen on local interfaces IPs)");
	extcap_help_add_option(extcap_conf, "--remote-count <count>", "the number of packets to capture");

	opterr = 0;
	optind = 0;

	if (argc == 1) {
		extcap_help_print(extcap_conf);
		goto end;
	}

	while ((result = getopt_long(argc, argv, ":", longopts, &option_idx)) != -1) {

		switch (result) {

		case OPT_HELP:
			extcap_help_print(extcap_conf);
			ret = EXIT_SUCCESS;
			goto end;

		case OPT_VERSION:
			printf("%s\n", extcap_conf->version);
			ret = EXIT_SUCCESS;
			goto end;

		case OPT_REMOTE_HOST:
			g_free(remote_host);
			remote_host = g_strdup(optarg);
			break;

		case OPT_REMOTE_PORT:
			if (!ws_strtou16(optarg, NULL, &remote_port) || remote_port == 0) {
				g_warning("Invalid port: %s", optarg);
				goto end;
			}
			break;

		case OPT_REMOTE_USERNAME:
			g_free(remote_username);
			remote_username = g_strdup(optarg);
			break;

		case OPT_REMOTE_PASSWORD:
			g_free(remote_password);
			remote_password = g_strdup(optarg);
			memset(optarg, 'X', strlen(optarg));
			break;

		case OPT_SSHKEY:
			g_free(sshkey);
			sshkey = g_strdup(optarg);
			break;

		case OPT_SSHKEY_PASSPHRASE:
			g_free(sshkey_passphrase);
			sshkey_passphrase = g_strdup(optarg);
			memset(optarg, 'X', strlen(optarg));
			break;

		case OPT_REMOTE_INTERFACE:
			g_free(remote_interface);
			remote_interface = g_strdup(optarg);
			break;

		case OPT_REMOTE_CAPTURE_COMMAND:
			g_free(remote_capture_command);
			remote_capture_command = g_strdup(optarg);
			break;

		case OPT_REMOTE_SUDO:
			use_sudo = TRUE;
			break;

		case OPT_REMOTE_FILTER:
			g_free(remote_filter);
			remote_filter = g_strdup(optarg);
			break;

		case OPT_REMOTE_COUNT:
			if (!ws_strtou32(optarg, NULL, &count)) {
				g_warning("Invalid value for count: %s", optarg);
				goto end;
			}
			break;

		case ':':
			/* missing option argument */
			g_warning("Option '%s' requires an argument", argv[optind - 1]);
			break;

		default:
			if (!extcap_base_parse_options(extcap_conf, result - EXTCAP_OPT_LIST_INTERFACES, optarg)) {
				g_warning("Invalid option: %s", argv[optind - 1]);
				goto end;
			}
		}
	}

	extcap_cmdline_debug(argv, argc);

	if (optind != argc) {
		g_warning("Unexpected extra option: %s", argv[optind]);
		goto end;
	}

	if (extcap_base_handle_interface(extcap_conf)) {
		ret = EXIT_SUCCESS;
		goto end;
	}

	if (extcap_conf->show_config) {
		ret = list_config(extcap_conf->interface, remote_port);
		goto end;
	}

#ifdef _WIN32
	result = WSAStartup(MAKEWORD(1,1), &wsaData);
	if (result != 0) {
		g_warning("ERROR: WSAStartup failed with error: %d", result);
		goto end;
	}
#endif  /* _WIN32 */

	if (extcap_conf->capture) {
		char* filter;

		if (!remote_host) {
			g_warning("Missing parameter: --remote-host");
			goto end;
		}
		filter = concat_filters(extcap_conf->capture_filter, remote_filter);
		ret = ssh_open_remote_connection(remote_host, remote_port, remote_username,
			remote_password, sshkey, sshkey_passphrase, remote_interface,
			filter, remote_capture_command, use_sudo, count, extcap_conf->fifo);
		g_free(filter);
	} else {
		g_debug("You should not come here... maybe some parameter missing?");
		ret = EXIT_FAILURE;
	}

end:
	/* clean up stuff */
	g_free(remote_host);
	g_free(remote_username);
	g_free(remote_password);
	g_free(remote_interface);
	g_free(remote_capture_command);
	g_free(sshkey);
	g_free(sshkey_passphrase);
	g_free(remote_filter);
	extcap_base_cleanup(&extcap_conf);
	return ret;
}

#ifdef _WIN32
int _stdcall
WinMain (struct HINSTANCE__ *hInstance,
        struct HINSTANCE__ *hPrevInstance,
        char               *lpszCmdLine,
        int                 nCmdShow)
{
	return main(__argc, __argv);
}
#endif

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */