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