/net/sched/act_ipt.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * net/sched/act_ipt.c		iptables target interface
  4 *
  5 *TODO: Add other tables. For now we only support the ipv4 table targets
  6 *
  7 * Copyright:	Jamal Hadi Salim (2002-13)
  8 */
  9
 10#include <linux/types.h>
 11#include <linux/kernel.h>
 12#include <linux/string.h>
 13#include <linux/errno.h>
 14#include <linux/skbuff.h>
 15#include <linux/rtnetlink.h>
 16#include <linux/module.h>
 17#include <linux/init.h>
 18#include <linux/slab.h>
 19#include <net/netlink.h>
 20#include <net/pkt_sched.h>
 21#include <linux/tc_act/tc_ipt.h>
 22#include <net/tc_act/tc_ipt.h>
 23
 24#include <linux/netfilter_ipv4/ip_tables.h>
 25
 26
 27static unsigned int ipt_net_id;
 28static struct tc_action_ops act_ipt_ops;
 29
 30static unsigned int xt_net_id;
 31static struct tc_action_ops act_xt_ops;
 32
 33static int ipt_init_target(struct net *net, struct xt_entry_target *t,
 34			   char *table, unsigned int hook)
 35{
 36	struct xt_tgchk_param par;
 37	struct xt_target *target;
 38	struct ipt_entry e = {};
 39	int ret = 0;
 40
 41	target = xt_request_find_target(AF_INET, t->u.user.name,
 42					t->u.user.revision);
 43	if (IS_ERR(target))
 44		return PTR_ERR(target);
 45
 46	t->u.kernel.target = target;
 47	memset(&par, 0, sizeof(par));
 48	par.net       = net;
 49	par.table     = table;
 50	par.entryinfo = &e;
 51	par.target    = target;
 52	par.targinfo  = t->data;
 53	par.hook_mask = hook;
 54	par.family    = NFPROTO_IPV4;
 55
 56	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 57	if (ret < 0) {
 58		module_put(t->u.kernel.target->me);
 59		return ret;
 60	}
 61	return 0;
 62}
 63
 64static void ipt_destroy_target(struct xt_entry_target *t, struct net *net)
 65{
 66	struct xt_tgdtor_param par = {
 67		.target   = t->u.kernel.target,
 68		.targinfo = t->data,
 69		.family   = NFPROTO_IPV4,
 70		.net      = net,
 71	};
 72	if (par.target->destroy != NULL)
 73		par.target->destroy(&par);
 74	module_put(par.target->me);
 75}
 76
 77static void tcf_ipt_release(struct tc_action *a)
 78{
 79	struct tcf_ipt *ipt = to_ipt(a);
 80
 81	if (ipt->tcfi_t) {
 82		ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
 83		kfree(ipt->tcfi_t);
 84	}
 85	kfree(ipt->tcfi_tname);
 86}
 87
 88static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
 89	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
 90	[TCA_IPT_HOOK]	= { .type = NLA_U32 },
 91	[TCA_IPT_INDEX]	= { .type = NLA_U32 },
 92	[TCA_IPT_TARG]	= { .len = sizeof(struct xt_entry_target) },
 93};
 94
 95static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 96			  struct nlattr *est, struct tc_action **a,
 97			  const struct tc_action_ops *ops, int ovr, int bind,
 98			  struct tcf_proto *tp, u32 flags)
 99{
100	struct tc_action_net *tn = net_generic(net, id);
101	struct nlattr *tb[TCA_IPT_MAX + 1];
102	struct tcf_ipt *ipt;
103	struct xt_entry_target *td, *t;
104	char *tname;
105	bool exists = false;
106	int ret = 0, err;
107	u32 hook = 0;
108	u32 index = 0;
109
110	if (nla == NULL)
111		return -EINVAL;
112
113	err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy,
114					  NULL);
115	if (err < 0)
116		return err;
117
118	if (tb[TCA_IPT_INDEX] != NULL)
119		index = nla_get_u32(tb[TCA_IPT_INDEX]);
120
121	err = tcf_idr_check_alloc(tn, &index, a, bind);
122	if (err < 0)
123		return err;
124	exists = err;
125	if (exists && bind)
126		return 0;
127
128	if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
129		if (exists)
130			tcf_idr_release(*a, bind);
131		else
132			tcf_idr_cleanup(tn, index);
133		return -EINVAL;
134	}
135
136	td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
137	if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) {
138		if (exists)
139			tcf_idr_release(*a, bind);
140		else
141			tcf_idr_cleanup(tn, index);
142		return -EINVAL;
143	}
144
145	if (!exists) {
146		ret = tcf_idr_create(tn, index, est, a, ops, bind,
147				     false, 0);
148		if (ret) {
149			tcf_idr_cleanup(tn, index);
150			return ret;
151		}
152		ret = ACT_P_CREATED;
153	} else {
154		if (bind)/* dont override defaults */
155			return 0;
156
157		if (!ovr) {
158			tcf_idr_release(*a, bind);
159			return -EEXIST;
160		}
161	}
162	hook = nla_get_u32(tb[TCA_IPT_HOOK]);
163
164	err = -ENOMEM;
165	tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
166	if (unlikely(!tname))
167		goto err1;
168	if (tb[TCA_IPT_TABLE] == NULL ||
169	    nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
170		strcpy(tname, "mangle");
171
172	t = kmemdup(td, td->u.target_size, GFP_KERNEL);
173	if (unlikely(!t))
174		goto err2;
175
176	err = ipt_init_target(net, t, tname, hook);
177	if (err < 0)
178		goto err3;
179
180	ipt = to_ipt(*a);
181
182	spin_lock_bh(&ipt->tcf_lock);
183	if (ret != ACT_P_CREATED) {
184		ipt_destroy_target(ipt->tcfi_t, net);
185		kfree(ipt->tcfi_tname);
186		kfree(ipt->tcfi_t);
187	}
188	ipt->tcfi_tname = tname;
189	ipt->tcfi_t     = t;
190	ipt->tcfi_hook  = hook;
191	spin_unlock_bh(&ipt->tcf_lock);
192	if (ret == ACT_P_CREATED)
193		tcf_idr_insert(tn, *a);
194	return ret;
195
196err3:
197	kfree(t);
198err2:
199	kfree(tname);
200err1:
201	tcf_idr_release(*a, bind);
202	return err;
203}
204
205static int tcf_ipt_init(struct net *net, struct nlattr *nla,
206			struct nlattr *est, struct tc_action **a, int ovr,
207			int bind, bool rtnl_held, struct tcf_proto *tp,
208			u32 flags, struct netlink_ext_ack *extack)
209{
210	return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
211			      bind, tp, flags);
212}
213
214static int tcf_xt_init(struct net *net, struct nlattr *nla,
215		       struct nlattr *est, struct tc_action **a, int ovr,
216		       int bind, bool unlocked, struct tcf_proto *tp,
217		       u32 flags, struct netlink_ext_ack *extack)
218{
219	return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
220			      bind, tp, flags);
221}
222
223static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a,
224		       struct tcf_result *res)
225{
226	int ret = 0, result = 0;
227	struct tcf_ipt *ipt = to_ipt(a);
228	struct xt_action_param par;
229	struct nf_hook_state state = {
230		.net	= dev_net(skb->dev),
231		.in	= skb->dev,
232		.hook	= ipt->tcfi_hook,
233		.pf	= NFPROTO_IPV4,
234	};
235
236	if (skb_unclone(skb, GFP_ATOMIC))
237		return TC_ACT_UNSPEC;
238
239	spin_lock(&ipt->tcf_lock);
240
241	tcf_lastuse_update(&ipt->tcf_tm);
242	bstats_update(&ipt->tcf_bstats, skb);
243
244	/* yes, we have to worry about both in and out dev
245	 * worry later - danger - this API seems to have changed
246	 * from earlier kernels
247	 */
248	par.state    = &state;
249	par.target   = ipt->tcfi_t->u.kernel.target;
250	par.targinfo = ipt->tcfi_t->data;
251	ret = par.target->target(skb, &par);
252
253	switch (ret) {
254	case NF_ACCEPT:
255		result = TC_ACT_OK;
256		break;
257	case NF_DROP:
258		result = TC_ACT_SHOT;
259		ipt->tcf_qstats.drops++;
260		break;
261	case XT_CONTINUE:
262		result = TC_ACT_PIPE;
263		break;
264	default:
265		net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
266				       ret);
267		result = TC_ACT_OK;
268		break;
269	}
270	spin_unlock(&ipt->tcf_lock);
271	return result;
272
273}
274
275static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
276			int ref)
277{
278	unsigned char *b = skb_tail_pointer(skb);
279	struct tcf_ipt *ipt = to_ipt(a);
280	struct xt_entry_target *t;
281	struct tcf_t tm;
282	struct tc_cnt c;
283
284	/* for simple targets kernel size == user size
285	 * user name = target name
286	 * for foolproof you need to not assume this
287	 */
288
289	spin_lock_bh(&ipt->tcf_lock);
290	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
291	if (unlikely(!t))
292		goto nla_put_failure;
293
294	c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
295	c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
296	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
297
298	if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
299	    nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
300	    nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
301	    nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
302	    nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
303		goto nla_put_failure;
304
305	tcf_tm_dump(&tm, &ipt->tcf_tm);
306	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
307		goto nla_put_failure;
308
309	spin_unlock_bh(&ipt->tcf_lock);
310	kfree(t);
311	return skb->len;
312
313nla_put_failure:
314	spin_unlock_bh(&ipt->tcf_lock);
315	nlmsg_trim(skb, b);
316	kfree(t);
317	return -1;
318}
319
320static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
321			  struct netlink_callback *cb, int type,
322			  const struct tc_action_ops *ops,
323			  struct netlink_ext_ack *extack)
324{
325	struct tc_action_net *tn = net_generic(net, ipt_net_id);
326
327	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
328}
329
330static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
331{
332	struct tc_action_net *tn = net_generic(net, ipt_net_id);
333
334	return tcf_idr_search(tn, a, index);
335}
336
337static struct tc_action_ops act_ipt_ops = {
338	.kind		=	"ipt",
339	.id		=	TCA_ID_IPT,
340	.owner		=	THIS_MODULE,
341	.act		=	tcf_ipt_act,
342	.dump		=	tcf_ipt_dump,
343	.cleanup	=	tcf_ipt_release,
344	.init		=	tcf_ipt_init,
345	.walk		=	tcf_ipt_walker,
346	.lookup		=	tcf_ipt_search,
347	.size		=	sizeof(struct tcf_ipt),
348};
349
350static __net_init int ipt_init_net(struct net *net)
351{
352	struct tc_action_net *tn = net_generic(net, ipt_net_id);
353
354	return tc_action_net_init(net, tn, &act_ipt_ops);
355}
356
357static void __net_exit ipt_exit_net(struct list_head *net_list)
358{
359	tc_action_net_exit(net_list, ipt_net_id);
360}
361
362static struct pernet_operations ipt_net_ops = {
363	.init = ipt_init_net,
364	.exit_batch = ipt_exit_net,
365	.id   = &ipt_net_id,
366	.size = sizeof(struct tc_action_net),
367};
368
369static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
370			 struct netlink_callback *cb, int type,
371			 const struct tc_action_ops *ops,
372			 struct netlink_ext_ack *extack)
373{
374	struct tc_action_net *tn = net_generic(net, xt_net_id);
375
376	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
377}
378
379static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
380{
381	struct tc_action_net *tn = net_generic(net, xt_net_id);
382
383	return tcf_idr_search(tn, a, index);
384}
385
386static struct tc_action_ops act_xt_ops = {
387	.kind		=	"xt",
388	.id		=	TCA_ID_XT,
389	.owner		=	THIS_MODULE,
390	.act		=	tcf_ipt_act,
391	.dump		=	tcf_ipt_dump,
392	.cleanup	=	tcf_ipt_release,
393	.init		=	tcf_xt_init,
394	.walk		=	tcf_xt_walker,
395	.lookup		=	tcf_xt_search,
396	.size		=	sizeof(struct tcf_ipt),
397};
398
399static __net_init int xt_init_net(struct net *net)
400{
401	struct tc_action_net *tn = net_generic(net, xt_net_id);
402
403	return tc_action_net_init(net, tn, &act_xt_ops);
404}
405
406static void __net_exit xt_exit_net(struct list_head *net_list)
407{
408	tc_action_net_exit(net_list, xt_net_id);
409}
410
411static struct pernet_operations xt_net_ops = {
412	.init = xt_init_net,
413	.exit_batch = xt_exit_net,
414	.id   = &xt_net_id,
415	.size = sizeof(struct tc_action_net),
416};
417
418MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
419MODULE_DESCRIPTION("Iptables target actions");
420MODULE_LICENSE("GPL");
421MODULE_ALIAS("act_xt");
422
423static int __init ipt_init_module(void)
424{
425	int ret1, ret2;
426
427	ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
428	if (ret1 < 0)
429		pr_err("Failed to load xt action\n");
430
431	ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
432	if (ret2 < 0)
433		pr_err("Failed to load ipt action\n");
434
435	if (ret1 < 0 && ret2 < 0) {
436		return ret1;
437	} else
438		return 0;
439}
440
441static void __exit ipt_cleanup_module(void)
442{
443	tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
444	tcf_unregister_action(&act_xt_ops, &xt_net_ops);
445}
446
447module_init(ipt_init_module);
448module_exit(ipt_cleanup_module);