summaryrefslogtreecommitdiff
path: root/src/firewall.c
blob: 90c3d3c1262e2169b90e21ccf30cf30355d21c43 (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
/*
 *
 *  Connection Manager
 *
 *  Copyright (C) 2013  BMW Car IT GmbH.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  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 St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <errno.h>

#include <xtables.h>
#include <linux/netfilter_ipv4/ip_tables.h>

#include "connman.h"

#define CHAIN_PREFIX "connman-"

static const char *builtin_chains[] = {
	[NF_IP_PRE_ROUTING]	= "PREROUTING",
	[NF_IP_LOCAL_IN]	= "INPUT",
	[NF_IP_FORWARD]		= "FORWARD",
	[NF_IP_LOCAL_OUT]	= "OUTPUT",
	[NF_IP_POST_ROUTING]	= "POSTROUTING",
};

struct connman_managed_table {
	char *name;
	unsigned int chains[NF_INET_NUMHOOKS];
};

struct fw_rule {
	char *table;
	char *chain;
	char *rule_spec;
};

struct firewall_context {
	GList *rules;
};

static GSList *managed_tables;

static bool firewall_is_up;

static int chain_to_index(const char *chain_name)
{
	if (!g_strcmp0(builtin_chains[NF_IP_PRE_ROUTING], chain_name))
		return NF_IP_PRE_ROUTING;
	if (!g_strcmp0(builtin_chains[NF_IP_LOCAL_IN], chain_name))
		return NF_IP_LOCAL_IN;
	if (!g_strcmp0(builtin_chains[NF_IP_FORWARD], chain_name))
		return NF_IP_FORWARD;
	if (!g_strcmp0(builtin_chains[NF_IP_LOCAL_OUT], chain_name))
		return NF_IP_LOCAL_OUT;
	if (!g_strcmp0(builtin_chains[NF_IP_POST_ROUTING], chain_name))
		return NF_IP_POST_ROUTING;

	return -1;
}

static int managed_chain_to_index(const char *chain_name)
{
	if (!g_str_has_prefix(chain_name, CHAIN_PREFIX))
		return -1;

	return chain_to_index(chain_name + strlen(CHAIN_PREFIX));
}

static int insert_managed_chain(const char *table_name, int id)
{
	char *rule, *managed_chain;
	int err;

	managed_chain = g_strdup_printf("%s%s", CHAIN_PREFIX,
					builtin_chains[id]);

	err = __connman_iptables_new_chain(table_name, managed_chain);
	if (err < 0)
		goto out;

	rule = g_strdup_printf("-j %s", managed_chain);
	err = __connman_iptables_insert(table_name, builtin_chains[id], rule);
	g_free(rule);
	if (err < 0) {
		__connman_iptables_delete_chain(table_name, managed_chain);
		goto out;
	}

out:
	g_free(managed_chain);

	return err;
}

static int delete_managed_chain(const char *table_name, int id)
{
	char *rule, *managed_chain;
	int err;

	managed_chain = g_strdup_printf("%s%s", CHAIN_PREFIX,
					builtin_chains[id]);

	rule = g_strdup_printf("-j %s", managed_chain);
	err = __connman_iptables_delete(table_name, builtin_chains[id], rule);
	g_free(rule);

	if (err < 0)
		goto out;

	err =  __connman_iptables_delete_chain(table_name, managed_chain);

out:
	g_free(managed_chain);

	return err;
}

static int insert_managed_rule(const char *table_name,
				const char *chain_name,
				const char *rule_spec)
{
	struct connman_managed_table *mtable = NULL;
	GSList *list;
	char *chain;
	int id, err;

	id = chain_to_index(chain_name);
	if (id < 0) {
		/* This chain is not managed */
		chain = g_strdup(chain_name);
		goto out;
	}

	for (list = managed_tables; list; list = list->next) {
		mtable = list->data;

		if (g_strcmp0(mtable->name, table_name) == 0)
			break;

		mtable = NULL;
	}

	if (!mtable) {
		mtable = g_new0(struct connman_managed_table, 1);
		mtable->name = g_strdup(table_name);

		managed_tables = g_slist_prepend(managed_tables, mtable);
	}

	if (mtable->chains[id] == 0) {
		DBG("table %s add managed chain for %s",
			table_name, chain_name);

		err = insert_managed_chain(table_name, id);
		if (err < 0)
			return err;
	}

	mtable->chains[id]++;
	chain = g_strdup_printf("%s%s", CHAIN_PREFIX, chain_name);

out:
	err = __connman_iptables_append(table_name, chain, rule_spec);

	g_free(chain);

	return err;
 }

static int delete_managed_rule(const char *table_name,
				const char *chain_name,
				const char *rule_spec)
 {
	struct connman_managed_table *mtable = NULL;
	GSList *list;
	int id, err;
	char *managed_chain;

	id = chain_to_index(chain_name);
	if (id < 0) {
		/* This chain is not managed */
		return __connman_iptables_delete(table_name, chain_name,
							rule_spec);
	}

	managed_chain = g_strdup_printf("%s%s", CHAIN_PREFIX, chain_name);

	err = __connman_iptables_delete(table_name, managed_chain,
					rule_spec);

	for (list = managed_tables; list; list = list->next) {
		mtable = list->data;

		if (g_strcmp0(mtable->name, table_name) == 0)
			break;

		mtable = NULL;
	}

	if (!mtable) {
		err = -ENOENT;
		goto out;
	}

	mtable->chains[id]--;
	if (mtable->chains[id] > 0)
		goto out;

	DBG("table %s remove managed chain for %s",
			table_name, chain_name);

	err = delete_managed_chain(table_name, id);

 out:
	g_free(managed_chain);

	return err;
}

static void cleanup_managed_table(gpointer user_data)
{
	struct connman_managed_table *table = user_data;

	g_free(table->name);
	g_free(table);
}

static void cleanup_fw_rule(gpointer user_data)
{
	struct fw_rule *rule = user_data;

	g_free(rule->rule_spec);
	g_free(rule->chain);
	g_free(rule->table);
	g_free(rule);
}

struct firewall_context *__connman_firewall_create(void)
{
	struct firewall_context *ctx;

	ctx = g_new0(struct firewall_context, 1);

	return ctx;
}

void __connman_firewall_destroy(struct firewall_context *ctx)
{
	g_list_free_full(ctx->rules, cleanup_fw_rule);
	g_free(ctx);
}

int __connman_firewall_add_rule(struct firewall_context *ctx,
				const char *table,
				const char *chain,
				const char *rule_fmt, ...)
{
	va_list args;
	char *rule_spec;
	struct fw_rule *rule;

	va_start(args, rule_fmt);

	rule_spec = g_strdup_vprintf(rule_fmt, args);

	va_end(args);

	rule = g_new0(struct fw_rule, 1);

	rule->table = g_strdup(table);
	rule->chain = g_strdup(chain);
	rule->rule_spec = rule_spec;

	ctx->rules = g_list_append(ctx->rules, rule);

	return 0;
}

static int firewall_disable(GList *rules)
{
	struct fw_rule *rule;
	GList *list;
	int err;

	for (list = rules; list; list = g_list_previous(list)) {
		rule = list->data;

		err = delete_managed_rule(rule->table,
						rule->chain, rule->rule_spec);
		if (err < 0) {
			connman_error("Cannot remove previously installed "
				"iptables rules: %s", strerror(-err));
			return err;
		}

		err = __connman_iptables_commit(rule->table);
		if (err < 0) {
			connman_error("Cannot remove previously installed "
				"iptables rules: %s", strerror(-err));
			return err;
		}
	}

	return 0;
}

int __connman_firewall_enable(struct firewall_context *ctx)
{
	struct fw_rule *rule;
	GList *list;
	int err;

	for (list = g_list_first(ctx->rules); list;
			list = g_list_next(list)) {
		rule = list->data;

		DBG("%s %s %s", rule->table, rule->chain, rule->rule_spec);

		err = insert_managed_rule(rule->table,
						rule->chain, rule->rule_spec);
		if (err < 0)
			goto err;

		err = __connman_iptables_commit(rule->table);
		if (err < 0)
			goto err;
	}

	firewall_is_up = true;

	return 0;

err:
	connman_warn("Failed to install iptables rules: %s", strerror(-err));

	firewall_disable(g_list_previous(list));

	return err;
}

int __connman_firewall_disable(struct firewall_context *ctx)
{
	return firewall_disable(g_list_last(ctx->rules));
}

bool __connman_firewall_is_up(void)
{
	return firewall_is_up;
}

static void iterate_chains_cb(const char *chain_name, void *user_data)
{
	GSList **chains = user_data;
	int id;

	id = managed_chain_to_index(chain_name);
	if (id < 0)
		return;

	*chains = g_slist_prepend(*chains, GINT_TO_POINTER(id));
}

static void flush_table(const char *table_name)
{
	GSList *chains = NULL, *list;
	char *rule, *managed_chain;
	int id, err;

	__connman_iptables_iterate_chains(table_name, iterate_chains_cb,
						&chains);

	for (list = chains; list; list = list->next) {
		id = GPOINTER_TO_INT(list->data);

		managed_chain = g_strdup_printf("%s%s", CHAIN_PREFIX,
						builtin_chains[id]);

		rule = g_strdup_printf("-j %s", managed_chain);
		err = __connman_iptables_delete(table_name,
						builtin_chains[id], rule);
		if (err < 0) {
			connman_warn("Failed to delete jump rule '%s': %s",
				rule, strerror(-err));
		}
		g_free(rule);

		err = __connman_iptables_flush_chain(table_name, managed_chain);
		if (err < 0) {
			connman_warn("Failed to flush chain '%s': %s",
				managed_chain, strerror(-err));
		}
		err = __connman_iptables_delete_chain(table_name, managed_chain);
		if (err < 0) {
			connman_warn("Failed to delete chain '%s': %s",
				managed_chain, strerror(-err));
		}

		g_free(managed_chain);
	}

	err = __connman_iptables_commit(table_name);
	if (err < 0) {
		connman_warn("Failed to flush table '%s': %s",
			table_name, strerror(-err));
	}

	g_slist_free(chains);
}

static void flush_all_tables(void)
{
	/* Flush the tables ConnMan might have modified
	 * But do so if only ConnMan has done something with
	 * iptables */

	if (!g_file_test("/proc/net/ip_tables_names",
			G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR)) {
		firewall_is_up = false;
		return;
	}

	firewall_is_up = true;

	flush_table("filter");
	flush_table("mangle");
	flush_table("nat");
}

int __connman_firewall_init(void)
{
	DBG("");

	flush_all_tables();

	return 0;
}

void __connman_firewall_cleanup(void)
{
	DBG("");

	g_slist_free_full(managed_tables, cleanup_managed_table);
}