1	// SPDX-License-Identifier: GPL-2.0-only
2	/*
3	* Packet matching code for ARP packets.
4	*
5	* Based heavily, if not almost entirely, upon ip_tables.c framework.
6	*
7	* Some ARP specific bits are:
8	*
9	* Copyright (C) 2002 David S. Miller (davem@redhat.com)
10	* Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
11	*
12	*/
13	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14	#include <linux/kernel.h>
15	#include <linux/skbuff.h>
16	#include <linux/netdevice.h>
17	#include <linux/capability.h>
18	#include <linux/if_arp.h>
19	#include <linux/kmod.h>
20	#include <linux/vmalloc.h>
21	#include <linux/proc_fs.h>
22	#include <linux/module.h>
23	#include <linux/init.h>
24	#include <linux/mutex.h>
25	#include <linux/err.h>
26	#include <net/compat.h>
27	#include <net/sock.h>
28	#include <linux/uaccess.h>
29
30	#include <linux/netfilter/x_tables.h>
31	#include <linux/netfilter_arp/arp_tables.h>
32	#include "../../netfilter/xt_repldata.h"
33
34	MODULE_LICENSE("GPL");
35	MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
36	MODULE_DESCRIPTION("arptables core");
37
38	void *arpt_alloc_initial_table(const struct xt_table *info)
39	{
40	return xt_alloc_initial_table(arpt, ARPT);
41	}
42	EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
43
44	static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
45	const char *hdr_addr, int len)
46	{
47	int i, ret;
48
49	if (len > ARPT_DEV_ADDR_LEN_MAX)
50	len = ARPT_DEV_ADDR_LEN_MAX;
51
52	ret = 0;
53	for (i = 0; i < len; i++)
54	ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
55
56	return ret != 0;
57	}
58
59	/*
60	* Unfortunately, _b and _mask are not aligned to an int (or long int)
61	* Some arches dont care, unrolling the loop is a win on them.
62	* For other arches, we only have a 16bit alignement.
63	*/
64	static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
65	{
66	#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
67	unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
68	#else
69	unsigned long ret = 0;
70	const u16 *a = (const u16 *)_a;
71	const u16 *b = (const u16 *)_b;
72	const u16 *mask = (const u16 *)_mask;
73	int i;
74
75	for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
76	ret |= (a[i] ^ b[i]) & mask[i];
77	#endif
78	return ret;
79	}
80
81	/* Returns whether packet matches rule or not. */
82	static inline int arp_packet_match(const struct arphdr *arphdr,
83	struct net_device *dev,
84	const char *indev,
85	const char *outdev,
86	const struct arpt_arp *arpinfo)
87	{
88	const char *arpptr = (char *)(arphdr + 1);
89	const char *src_devaddr, *tgt_devaddr;
90	__be32 src_ipaddr, tgt_ipaddr;
91	long ret;
92
93	if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
94	(arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
95	return 0;
96
97	if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
98	(arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
99	return 0;
100
101	if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
102	(arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
103	return 0;
104
105	if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
106	(arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
107	return 0;
108
109	src_devaddr = arpptr;
110	arpptr += dev->addr_len;
111	memcpy(&src_ipaddr, arpptr, sizeof(u32));
112	arpptr += sizeof(u32);
113	tgt_devaddr = arpptr;
114	arpptr += dev->addr_len;
115	memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
116
117	if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
118	arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
119	dev->addr_len)) ||
120	NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
121	arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
122	dev->addr_len)))
123	return 0;
124
125	if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
126	(src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
127	NF_INVF(arpinfo, ARPT_INV_TGTIP,
128	(tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
129	return 0;
130
131	/* Look for ifname matches. */
132	ret = ifname_compare(a: indev, b: arpinfo->iniface, mask: arpinfo->iniface_mask);
133
134	if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
135	return 0;
136
137	ret = ifname_compare(a: outdev, b: arpinfo->outiface, mask: arpinfo->outiface_mask);
138
139	if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
140	return 0;
141
142	return 1;
143	}
144
145	static inline int arp_checkentry(const struct arpt_arp *arp)
146	{
147	if (arp->flags & ~ARPT_F_MASK)
148	return 0;
149	if (arp->invflags & ~ARPT_INV_MASK)
150	return 0;
151
152	return 1;
153	}
154
155	static unsigned int
156	arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
157	{
158	net_err_ratelimited("arp_tables: error: '%s'\n",
159	(const char *)par->targinfo);
160
161	return NF_DROP;
162	}
163
164	static inline const struct xt_entry_target *
165	arpt_get_target_c(const struct arpt_entry *e)
166	{
167	return arpt_get_target(e: (struct arpt_entry *)e);
168	}
169
170	static inline struct arpt_entry *
171	get_entry(const void *base, unsigned int offset)
172	{
173	return (struct arpt_entry *)(base + offset);
174	}
175
176	static inline
177	struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
178	{
179	return (void *)entry + entry->next_offset;
180	}
181
182	unsigned int arpt_do_table(void *priv,
183	struct sk_buff *skb,
184	const struct nf_hook_state *state)
185	{
186	const struct xt_table *table = priv;
187	unsigned int hook = state->hook;
188	static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
189	unsigned int verdict = NF_DROP;
190	const struct arphdr *arp;
191	struct arpt_entry *e, **jumpstack;
192	const char *indev, *outdev;
193	const void *table_base;
194	unsigned int cpu, stackidx = 0;
195	const struct xt_table_info *private;
196	struct xt_action_param acpar;
197	unsigned int addend;
198
199	if (!pskb_may_pull(skb, len: arp_hdr_len(dev: skb->dev)))
200	return NF_DROP;
201
202	indev = state->in ? state->in->name : nulldevname;
203	outdev = state->out ? state->out->name : nulldevname;
204
205	local_bh_disable();
206	addend = xt_write_recseq_begin();
207	private = READ_ONCE(table->private); /* Address dependency. */
208	cpu = smp_processor_id();
209	table_base = private->entries;
210	jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
211
212	/* No TEE support for arptables, so no need to switch to alternate
213	* stack. All targets that reenter must return absolute verdicts.
214	*/
215	e = get_entry(base: table_base, offset: private->hook_entry[hook]);
216
217	acpar.state = state;
218	acpar.hotdrop = false;
219
220	arp = arp_hdr(skb);
221	do {
222	const struct xt_entry_target *t;
223	struct xt_counters *counter;
224
225	if (!arp_packet_match(arphdr: arp, dev: skb->dev, indev, outdev, arpinfo: &e->arp)) {
226	e = arpt_next_entry(entry: e);
227	continue;
228	}
229
230	counter = xt_get_this_cpu_counter(cnt: &e->counters);
231	ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
232
233	t = arpt_get_target_c(e);
234
235	/* Standard target? */
236	if (!t->u.kernel.target->target) {
237	int v;
238
239	v = ((struct xt_standard_target *)t)->verdict;
240	if (v < 0) {
241	/* Pop from stack? */
242	if (v != XT_RETURN) {
243	verdict = (unsigned int)(-v) - 1;
244	break;
245	}
246	if (stackidx == 0) {
247	e = get_entry(base: table_base,
248	offset: private->underflow[hook]);
249	} else {
250	e = jumpstack[--stackidx];
251	e = arpt_next_entry(entry: e);
252	}
253	continue;
254	}
255	if (table_base + v
256	!= arpt_next_entry(entry: e)) {
257	if (unlikely(stackidx >= private->stacksize)) {
258	verdict = NF_DROP;
259	break;
260	}
261	jumpstack[stackidx++] = e;
262	}
263
264	e = get_entry(base: table_base, offset: v);
265	continue;
266	}
267
268	acpar.target = t->u.kernel.target;
269	acpar.targinfo = t->data;
270	verdict = t->u.kernel.target->target(skb, &acpar);
271
272	if (verdict == XT_CONTINUE) {
273	/* Target might have changed stuff. */
274	arp = arp_hdr(skb);
275	e = arpt_next_entry(entry: e);
276	} else {
277	/* Verdict */
278	break;
279	}
280	} while (!acpar.hotdrop);
281	xt_write_recseq_end(addend);
282	local_bh_enable();
283
284	if (acpar.hotdrop)
285	return NF_DROP;
286	else
287	return verdict;
288	}
289
290	/* All zeroes == unconditional rule. */
291	static inline bool unconditional(const struct arpt_entry *e)
292	{
293	static const struct arpt_arp uncond;
294
295	return e->target_offset == sizeof(struct arpt_entry) &&
296	memcmp(p: &e->arp, q: &uncond, size: sizeof(uncond)) == 0;
297	}
298
299	/* Figures out from what hook each rule can be called: returns 0 if
300	* there are loops. Puts hook bitmask in comefrom.
301	*/
302	static int mark_source_chains(const struct xt_table_info *newinfo,
303	unsigned int valid_hooks, void *entry0,
304	unsigned int *offsets)
305	{
306	unsigned int hook;
307
308	/* No recursion; use packet counter to save back ptrs (reset
309	* to 0 as we leave), and comefrom to save source hook bitmask.
310	*/
311	for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
312	unsigned int pos = newinfo->hook_entry[hook];
313	struct arpt_entry *e = entry0 + pos;
314
315	if (!(valid_hooks & (1 << hook)))
316	continue;
317
318	/* Set initial back pointer. */
319	e->counters.pcnt = pos;
320
321	for (;;) {
322	const struct xt_standard_target *t
323	= (void *)arpt_get_target_c(e);
324	int visited = e->comefrom & (1 << hook);
325
326	if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
327	return 0;
328
329	e->comefrom
330	|= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
331
332	/* Unconditional return/END. */
333	if ((unconditional(e) &&
334	(strcmp(t->target.u.user.name,
335	XT_STANDARD_TARGET) == 0) &&
336	t->verdict < 0) || visited) {
337	unsigned int oldpos, size;
338
339	/* Return: backtrack through the last
340	* big jump.
341	*/
342	do {
343	e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
344	oldpos = pos;
345	pos = e->counters.pcnt;
346	e->counters.pcnt = 0;
347
348	/* We're at the start. */
349	if (pos == oldpos)
350	goto next;
351
352	e = entry0 + pos;
353	} while (oldpos == pos + e->next_offset);
354
355	/* Move along one */
356	size = e->next_offset;
357	e = entry0 + pos + size;
358	if (pos + size >= newinfo->size)
359	return 0;
360	e->counters.pcnt = pos;
361	pos += size;
362	} else {
363	int newpos = t->verdict;
364
365	if (strcmp(t->target.u.user.name,
366	XT_STANDARD_TARGET) == 0 &&
367	newpos >= 0) {
368	/* This a jump; chase it. */
369	if (!xt_find_jump_offset(offsets, target: newpos,
370	size: newinfo->number))
371	return 0;
372	} else {
373	/* ... this is a fallthru */
374	newpos = pos + e->next_offset;
375	if (newpos >= newinfo->size)
376	return 0;
377	}
378	e = entry0 + newpos;
379	e->counters.pcnt = pos;
380	pos = newpos;
381	}
382	}
383	next: ;
384	}
385	return 1;
386	}
387
388	static int check_target(struct arpt_entry *e, struct net *net, const char *name)
389	{
390	struct xt_entry_target *t = arpt_get_target(e);
391	struct xt_tgchk_param par = {
392	.net = net,
393	.table = name,
394	.entryinfo = e,
395	.target = t->u.kernel.target,
396	.targinfo = t->data,
397	.hook_mask = e->comefrom,
398	.family = NFPROTO_ARP,
399	};
400
401	return xt_check_target(&par, size: t->u.target_size - sizeof(*t), proto: 0, inv_proto: false);
402	}
403
404	static int
405	find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
406	unsigned int size,
407	struct xt_percpu_counter_alloc_state *alloc_state)
408	{
409	struct xt_entry_target *t;
410	struct xt_target *target;
411	int ret;
412
413	if (!xt_percpu_counter_alloc(state: alloc_state, counter: &e->counters))
414	return -ENOMEM;
415
416	t = arpt_get_target(e);
417	target = xt_request_find_target(af: NFPROTO_ARP, name: t->u.user.name,
418	revision: t->u.user.revision);
419	if (IS_ERR(ptr: target)) {
420	ret = PTR_ERR(ptr: target);
421	goto out;
422	}
423	t->u.kernel.target = target;
424
425	ret = check_target(e, net, name);
426	if (ret)
427	goto err;
428	return 0;
429	err:
430	module_put(module: t->u.kernel.target->me);
431	out:
432	xt_percpu_counter_free(cnt: &e->counters);
433
434	return ret;
435	}
436
437	static bool check_underflow(const struct arpt_entry *e)
438	{
439	const struct xt_entry_target *t;
440	unsigned int verdict;
441
442	if (!unconditional(e))
443	return false;
444	t = arpt_get_target_c(e);
445	if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
446	return false;
447	verdict = ((struct xt_standard_target *)t)->verdict;
448	verdict = -verdict - 1;
449	return verdict == NF_DROP || verdict == NF_ACCEPT;
450	}
451
452	static inline int check_entry_size_and_hooks(struct arpt_entry *e,
453	struct xt_table_info *newinfo,
454	const unsigned char *base,
455	const unsigned char *limit,
456	const unsigned int *hook_entries,
457	const unsigned int *underflows,
458	unsigned int valid_hooks)
459	{
460	unsigned int h;
461	int err;
462
463	if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
464	(unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
465	(unsigned char *)e + e->next_offset > limit)
466	return -EINVAL;
467
468	if (e->next_offset
469	< sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
470	return -EINVAL;
471
472	if (!arp_checkentry(arp: &e->arp))
473	return -EINVAL;
474
475	err = xt_check_entry_offsets(base: e, elems: e->elems, target_offset: e->target_offset,
476	next_offset: e->next_offset);
477	if (err)
478	return err;
479
480	/* Check hooks & underflows */
481	for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
482	if (!(valid_hooks & (1 << h)))
483	continue;
484	if ((unsigned char *)e - base == hook_entries[h])
485	newinfo->hook_entry[h] = hook_entries[h];
486	if ((unsigned char *)e - base == underflows[h]) {
487	if (!check_underflow(e))
488	return -EINVAL;
489
490	newinfo->underflow[h] = underflows[h];
491	}
492	}
493
494	/* Clear counters and comefrom */
495	e->counters = ((struct xt_counters) { 0, 0 });
496	e->comefrom = 0;
497	return 0;
498	}
499
500	static void cleanup_entry(struct arpt_entry *e, struct net *net)
501	{
502	struct xt_tgdtor_param par;
503	struct xt_entry_target *t;
504
505	t = arpt_get_target(e);
506	par.net = net;
507	par.target = t->u.kernel.target;
508	par.targinfo = t->data;
509	par.family = NFPROTO_ARP;
510	if (par.target->destroy != NULL)
511	par.target->destroy(&par);
512	module_put(module: par.target->me);
513	xt_percpu_counter_free(cnt: &e->counters);
514	}
515
516	/* Checks and translates the user-supplied table segment (held in
517	* newinfo).
518	*/
519	static int translate_table(struct net *net,
520	struct xt_table_info *newinfo,
521	void *entry0,
522	const struct arpt_replace *repl)
523	{
524	struct xt_percpu_counter_alloc_state alloc_state = { 0 };
525	struct arpt_entry *iter;
526	unsigned int *offsets;
527	unsigned int i;
528	int ret = 0;
529
530	newinfo->size = repl->size;
531	newinfo->number = repl->num_entries;
532
533	/* Init all hooks to impossible value. */
534	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
535	newinfo->hook_entry[i] = 0xFFFFFFFF;
536	newinfo->underflow[i] = 0xFFFFFFFF;
537	}
538
539	offsets = xt_alloc_entry_offsets(size: newinfo->number);
540	if (!offsets)
541	return -ENOMEM;
542	i = 0;
543
544	/* Walk through entries, checking offsets. */
545	xt_entry_foreach(iter, entry0, newinfo->size) {
546	ret = check_entry_size_and_hooks(e: iter, newinfo, base: entry0,
547	limit: entry0 + repl->size,
548	hook_entries: repl->hook_entry,
549	underflows: repl->underflow,
550	valid_hooks: repl->valid_hooks);
551	if (ret != 0)
552	goto out_free;
553	if (i < repl->num_entries)
554	offsets[i] = (void *)iter - entry0;
555	++i;
556	if (strcmp(arpt_get_target(e: iter)->u.user.name,
557	XT_ERROR_TARGET) == 0)
558	++newinfo->stacksize;
559	}
560
561	ret = -EINVAL;
562	if (i != repl->num_entries)
563	goto out_free;
564
565	ret = xt_check_table_hooks(info: newinfo, valid_hooks: repl->valid_hooks);
566	if (ret)
567	goto out_free;
568
569	if (!mark_source_chains(newinfo, valid_hooks: repl->valid_hooks, entry0, offsets)) {
570	ret = -ELOOP;
571	goto out_free;
572	}
573	kvfree(addr: offsets);
574
575	/* Finally, each sanity check must pass */
576	i = 0;
577	xt_entry_foreach(iter, entry0, newinfo->size) {
578	ret = find_check_entry(e: iter, net, name: repl->name, size: repl->size,
579	alloc_state: &alloc_state);
580	if (ret != 0)
581	break;
582	++i;
583	}
584
585	if (ret != 0) {
586	xt_entry_foreach(iter, entry0, newinfo->size) {
587	if (i-- == 0)
588	break;
589	cleanup_entry(e: iter, net);
590	}
591	return ret;
592	}
593
594	return ret;
595	out_free:
596	kvfree(addr: offsets);
597	return ret;
598	}
599
600	static void get_counters(const struct xt_table_info *t,
601	struct xt_counters counters[])
602	{
603	struct arpt_entry *iter;
604	unsigned int cpu;
605	unsigned int i;
606
607	for_each_possible_cpu(cpu) {
608	seqcount_t *s = &per_cpu(xt_recseq, cpu);
609
610	i = 0;
611	xt_entry_foreach(iter, t->entries, t->size) {
612	struct xt_counters *tmp;
613	u64 bcnt, pcnt;
614	unsigned int start;
615
616	tmp = xt_get_per_cpu_counter(cnt: &iter->counters, cpu);
617	do {
618	start = read_seqcount_begin(s);
619	bcnt = tmp->bcnt;
620	pcnt = tmp->pcnt;
621	} while (read_seqcount_retry(s, start));
622
623	ADD_COUNTER(counters[i], bcnt, pcnt);
624	++i;
625	cond_resched();
626	}
627	}
628	}
629
630	static void get_old_counters(const struct xt_table_info *t,
631	struct xt_counters counters[])
632	{
633	struct arpt_entry *iter;
634	unsigned int cpu, i;
635
636	for_each_possible_cpu(cpu) {
637	i = 0;
638	xt_entry_foreach(iter, t->entries, t->size) {
639	struct xt_counters *tmp;
640
641	tmp = xt_get_per_cpu_counter(cnt: &iter->counters, cpu);
642	ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
643	++i;
644	}
645	cond_resched();
646	}
647	}
648
649	static struct xt_counters *alloc_counters(const struct xt_table *table)
650	{
651	unsigned int countersize;
652	struct xt_counters *counters;
653	const struct xt_table_info *private = table->private;
654
655	/* We need atomic snapshot of counters: rest doesn't change
656	* (other than comefrom, which userspace doesn't care
657	* about).
658	*/
659	countersize = sizeof(struct xt_counters) * private->number;
660	counters = vzalloc(size: countersize);
661
662	if (counters == NULL)
663	return ERR_PTR(error: -ENOMEM);
664
665	get_counters(t: private, counters);
666
667	return counters;
668	}
669
670	static int copy_entries_to_user(unsigned int total_size,
671	const struct xt_table *table,
672	void __user *userptr)
673	{
674	unsigned int off, num;
675	const struct arpt_entry *e;
676	struct xt_counters *counters;
677	struct xt_table_info *private = table->private;
678	int ret = 0;
679	void *loc_cpu_entry;
680
681	counters = alloc_counters(table);
682	if (IS_ERR(ptr: counters))
683	return PTR_ERR(ptr: counters);
684
685	loc_cpu_entry = private->entries;
686
687	/* FIXME: use iterator macros --RR */
688	/* ... then go back and fix counters and names */
689	for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
690	const struct xt_entry_target *t;
691
692	e = loc_cpu_entry + off;
693	if (copy_to_user(to: userptr + off, from: e, n: sizeof(*e))) {
694	ret = -EFAULT;
695	goto free_counters;
696	}
697	if (copy_to_user(to: userptr + off
698	+ offsetof(struct arpt_entry, counters),
699	from: &counters[num],
700	n: sizeof(counters[num])) != 0) {
701	ret = -EFAULT;
702	goto free_counters;
703	}
704
705	t = arpt_get_target_c(e);
706	if (xt_target_to_user(t, u: userptr + off + e->target_offset)) {
707	ret = -EFAULT;
708	goto free_counters;
709	}
710	}
711
712	free_counters:
713	vfree(addr: counters);
714	return ret;
715	}
716
717	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
718	static void compat_standard_from_user(void *dst, const void *src)
719	{
720	int v = *(compat_int_t *)src;
721
722	if (v > 0)
723	v += xt_compat_calc_jump(af: NFPROTO_ARP, offset: v);
724	memcpy(dst, &v, sizeof(v));
725	}
726
727	static int compat_standard_to_user(void __user *dst, const void *src)
728	{
729	compat_int_t cv = *(int *)src;
730
731	if (cv > 0)
732	cv -= xt_compat_calc_jump(af: NFPROTO_ARP, offset: cv);
733	return copy_to_user(to: dst, from: &cv, n: sizeof(cv)) ? -EFAULT : 0;
734	}
735
736	static int compat_calc_entry(const struct arpt_entry *e,
737	const struct xt_table_info *info,
738	const void *base, struct xt_table_info *newinfo)
739	{
740	const struct xt_entry_target *t;
741	unsigned int entry_offset;
742	int off, i, ret;
743
744	off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
745	entry_offset = (void *)e - base;
746
747	t = arpt_get_target_c(e);
748	off += xt_compat_target_offset(target: t->u.kernel.target);
749	newinfo->size -= off;
750	ret = xt_compat_add_offset(af: NFPROTO_ARP, offset: entry_offset, delta: off);
751	if (ret)
752	return ret;
753
754	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
755	if (info->hook_entry[i] &&
756	(e < (struct arpt_entry *)(base + info->hook_entry[i])))
757	newinfo->hook_entry[i] -= off;
758	if (info->underflow[i] &&
759	(e < (struct arpt_entry *)(base + info->underflow[i])))
760	newinfo->underflow[i] -= off;
761	}
762	return 0;
763	}
764
765	static int compat_table_info(const struct xt_table_info *info,
766	struct xt_table_info *newinfo)
767	{
768	struct arpt_entry *iter;
769	const void *loc_cpu_entry;
770	int ret;
771
772	if (!newinfo || !info)
773	return -EINVAL;
774
775	/* we dont care about newinfo->entries */
776	memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
777	newinfo->initial_entries = 0;
778	loc_cpu_entry = info->entries;
779	ret = xt_compat_init_offsets(af: NFPROTO_ARP, number: info->number);
780	if (ret)
781	return ret;
782	xt_entry_foreach(iter, loc_cpu_entry, info->size) {
783	ret = compat_calc_entry(e: iter, info, base: loc_cpu_entry, newinfo);
784	if (ret != 0)
785	return ret;
786	}
787	return 0;
788	}
789	#endif
790
791	static int get_info(struct net *net, void __user *user, const int *len)
792	{
793	char name[XT_TABLE_MAXNAMELEN];
794	struct xt_table *t;
795	int ret;
796
797	if (*len != sizeof(struct arpt_getinfo))
798	return -EINVAL;
799
800	if (copy_from_user(to: name, from: user, n: sizeof(name)) != 0)
801	return -EFAULT;
802
803	name[XT_TABLE_MAXNAMELEN-1] = '\0';
804	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
805	if (in_compat_syscall())
806	xt_compat_lock(af: NFPROTO_ARP);
807	#endif
808	t = xt_request_find_table_lock(net, af: NFPROTO_ARP, name);
809	if (!IS_ERR(ptr: t)) {
810	struct arpt_getinfo info;
811	const struct xt_table_info *private = t->private;
812	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
813	struct xt_table_info tmp;
814
815	if (in_compat_syscall()) {
816	ret = compat_table_info(info: private, newinfo: &tmp);
817	xt_compat_flush_offsets(af: NFPROTO_ARP);
818	private = &tmp;
819	}
820	#endif
821	memset(&info, 0, sizeof(info));
822	info.valid_hooks = t->valid_hooks;
823	memcpy(info.hook_entry, private->hook_entry,
824	sizeof(info.hook_entry));
825	memcpy(info.underflow, private->underflow,
826	sizeof(info.underflow));
827	info.num_entries = private->number;
828	info.size = private->size;
829	strcpy(p: info.name, q: name);
830
831	if (copy_to_user(to: user, from: &info, n: *len) != 0)
832	ret = -EFAULT;
833	else
834	ret = 0;
835	xt_table_unlock(t);
836	module_put(module: t->me);
837	} else
838	ret = PTR_ERR(ptr: t);
839	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
840	if (in_compat_syscall())
841	xt_compat_unlock(af: NFPROTO_ARP);
842	#endif
843	return ret;
844	}
845
846	static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
847	const int *len)
848	{
849	int ret;
850	struct arpt_get_entries get;
851	struct xt_table *t;
852
853	if (*len < sizeof(get))
854	return -EINVAL;
855	if (copy_from_user(to: &get, from: uptr, n: sizeof(get)) != 0)
856	return -EFAULT;
857	if (*len != sizeof(struct arpt_get_entries) + get.size)
858	return -EINVAL;
859
860	get.name[sizeof(get.name) - 1] = '\0';
861
862	t = xt_find_table_lock(net, af: NFPROTO_ARP, name: get.name);
863	if (!IS_ERR(ptr: t)) {
864	const struct xt_table_info *private = t->private;
865
866	if (get.size == private->size)
867	ret = copy_entries_to_user(total_size: private->size,
868	table: t, userptr: uptr->entrytable);
869	else
870	ret = -EAGAIN;
871
872	module_put(module: t->me);
873	xt_table_unlock(t);
874	} else
875	ret = PTR_ERR(ptr: t);
876
877	return ret;
878	}
879
880	static int __do_replace(struct net *net, const char *name,
881	unsigned int valid_hooks,
882	struct xt_table_info *newinfo,
883	unsigned int num_counters,
884	void __user *counters_ptr)
885	{
886	int ret;
887	struct xt_table *t;
888	struct xt_table_info *oldinfo;
889	struct xt_counters *counters;
890	void *loc_cpu_old_entry;
891	struct arpt_entry *iter;
892
893	ret = 0;
894	counters = xt_counters_alloc(counters: num_counters);
895	if (!counters) {
896	ret = -ENOMEM;
897	goto out;
898	}
899
900	t = xt_request_find_table_lock(net, af: NFPROTO_ARP, name);
901	if (IS_ERR(ptr: t)) {
902	ret = PTR_ERR(ptr: t);
903	goto free_newinfo_counters_untrans;
904	}
905
906	/* You lied! */
907	if (valid_hooks != t->valid_hooks) {
908	ret = -EINVAL;
909	goto put_module;
910	}
911
912	oldinfo = xt_replace_table(table: t, num_counters, newinfo, error: &ret);
913	if (!oldinfo)
914	goto put_module;
915
916	/* Update module usage count based on number of rules */
917	if ((oldinfo->number > oldinfo->initial_entries) ||
918	(newinfo->number <= oldinfo->initial_entries))
919	module_put(module: t->me);
920	if ((oldinfo->number > oldinfo->initial_entries) &&
921	(newinfo->number <= oldinfo->initial_entries))
922	module_put(module: t->me);
923
924	xt_table_unlock(t);
925
926	get_old_counters(t: oldinfo, counters);
927
928	/* Decrease module usage counts and free resource */
929	loc_cpu_old_entry = oldinfo->entries;
930	xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
931	cleanup_entry(e: iter, net);
932
933	xt_free_table_info(info: oldinfo);
934	if (copy_to_user(to: counters_ptr, from: counters,
935	n: sizeof(struct xt_counters) * num_counters) != 0) {
936	/* Silent error, can't fail, new table is already in place */
937	net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
938	}
939	vfree(addr: counters);
940	return ret;
941
942	put_module:
943	module_put(module: t->me);
944	xt_table_unlock(t);
945	free_newinfo_counters_untrans:
946	vfree(addr: counters);
947	out:
948	return ret;
949	}
950
951	static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
952	{
953	int ret;
954	struct arpt_replace tmp;
955	struct xt_table_info *newinfo;
956	void *loc_cpu_entry;
957	struct arpt_entry *iter;
958
959	if (copy_from_sockptr(dst: &tmp, src: arg, size: sizeof(tmp)) != 0)
960	return -EFAULT;
961
962	/* overflow check */
963	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
964	return -ENOMEM;
965	if (tmp.num_counters == 0)
966	return -EINVAL;
967
968	tmp.name[sizeof(tmp.name)-1] = 0;
969
970	newinfo = xt_alloc_table_info(size: tmp.size);
971	if (!newinfo)
972	return -ENOMEM;
973
974	loc_cpu_entry = newinfo->entries;
975	if (copy_from_sockptr_offset(dst: loc_cpu_entry, src: arg, offset: sizeof(tmp),
976	size: tmp.size) != 0) {
977	ret = -EFAULT;
978	goto free_newinfo;
979	}
980
981	ret = translate_table(net, newinfo, entry0: loc_cpu_entry, repl: &tmp);
982	if (ret != 0)
983	goto free_newinfo;
984
985	ret = __do_replace(net, name: tmp.name, valid_hooks: tmp.valid_hooks, newinfo,
986	num_counters: tmp.num_counters, counters_ptr: tmp.counters);
987	if (ret)
988	goto free_newinfo_untrans;
989	return 0;
990
991	free_newinfo_untrans:
992	xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
993	cleanup_entry(e: iter, net);
994	free_newinfo:
995	xt_free_table_info(info: newinfo);
996	return ret;
997	}
998
999	static int do_add_counters(struct net *net, sockptr_t arg, unsigned int len)
1000	{
1001	unsigned int i;
1002	struct xt_counters_info tmp;
1003	struct xt_counters *paddc;
1004	struct xt_table *t;
1005	const struct xt_table_info *private;
1006	int ret = 0;
1007	struct arpt_entry *iter;
1008	unsigned int addend;
1009
1010	paddc = xt_copy_counters(arg, len, info: &tmp);
1011	if (IS_ERR(ptr: paddc))
1012	return PTR_ERR(ptr: paddc);
1013
1014	t = xt_find_table_lock(net, af: NFPROTO_ARP, name: tmp.name);
1015	if (IS_ERR(ptr: t)) {
1016	ret = PTR_ERR(ptr: t);
1017	goto free;
1018	}
1019
1020	local_bh_disable();
1021	private = t->private;
1022	if (private->number != tmp.num_counters) {
1023	ret = -EINVAL;
1024	goto unlock_up_free;
1025	}
1026
1027	i = 0;
1028
1029	addend = xt_write_recseq_begin();
1030	xt_entry_foreach(iter, private->entries, private->size) {
1031	struct xt_counters *tmp;
1032
1033	tmp = xt_get_this_cpu_counter(cnt: &iter->counters);
1034	ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1035	++i;
1036	}
1037	xt_write_recseq_end(addend);
1038	unlock_up_free:
1039	local_bh_enable();
1040	xt_table_unlock(t);
1041	module_put(module: t->me);
1042	free:
1043	vfree(addr: paddc);
1044
1045	return ret;
1046	}
1047
1048	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1049	struct compat_arpt_replace {
1050	char name[XT_TABLE_MAXNAMELEN];
1051	u32 valid_hooks;
1052	u32 num_entries;
1053	u32 size;
1054	u32 hook_entry[NF_ARP_NUMHOOKS];
1055	u32 underflow[NF_ARP_NUMHOOKS];
1056	u32 num_counters;
1057	compat_uptr_t counters;
1058	struct compat_arpt_entry entries[];
1059	};
1060
1061	static inline void compat_release_entry(struct compat_arpt_entry *e)
1062	{
1063	struct xt_entry_target *t;
1064
1065	t = compat_arpt_get_target(e);
1066	module_put(module: t->u.kernel.target->me);
1067	}
1068
1069	static int
1070	check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1071	struct xt_table_info *newinfo,
1072	unsigned int *size,
1073	const unsigned char *base,
1074	const unsigned char *limit)
1075	{
1076	struct xt_entry_target *t;
1077	struct xt_target *target;
1078	unsigned int entry_offset;
1079	int ret, off;
1080
1081	if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1082	(unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1083	(unsigned char *)e + e->next_offset > limit)
1084	return -EINVAL;
1085
1086	if (e->next_offset < sizeof(struct compat_arpt_entry) +
1087	sizeof(struct compat_xt_entry_target))
1088	return -EINVAL;
1089
1090	if (!arp_checkentry(arp: &e->arp))
1091	return -EINVAL;
1092
1093	ret = xt_compat_check_entry_offsets(base: e, elems: e->elems, target_offset: e->target_offset,
1094	next_offset: e->next_offset);
1095	if (ret)
1096	return ret;
1097
1098	off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1099	entry_offset = (void *)e - (void *)base;
1100
1101	t = compat_arpt_get_target(e);
1102	target = xt_request_find_target(af: NFPROTO_ARP, name: t->u.user.name,
1103	revision: t->u.user.revision);
1104	if (IS_ERR(ptr: target)) {
1105	ret = PTR_ERR(ptr: target);
1106	goto out;
1107	}
1108	t->u.kernel.target = target;
1109
1110	off += xt_compat_target_offset(target);
1111	*size += off;
1112	ret = xt_compat_add_offset(af: NFPROTO_ARP, offset: entry_offset, delta: off);
1113	if (ret)
1114	goto release_target;
1115
1116	return 0;
1117
1118	release_target:
1119	module_put(module: t->u.kernel.target->me);
1120	out:
1121	return ret;
1122	}
1123
1124	static void
1125	compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1126	unsigned int *size,
1127	struct xt_table_info *newinfo, unsigned char *base)
1128	{
1129	struct xt_entry_target *t;
1130	struct arpt_entry *de;
1131	unsigned int origsize;
1132	int h;
1133
1134	origsize = *size;
1135	de = *dstptr;
1136	memcpy(de, e, sizeof(struct arpt_entry));
1137	memcpy(&de->counters, &e->counters, sizeof(e->counters));
1138
1139	*dstptr += sizeof(struct arpt_entry);
1140	*size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1141
1142	de->target_offset = e->target_offset - (origsize - *size);
1143	t = compat_arpt_get_target(e);
1144	xt_compat_target_from_user(t, dstptr, size);
1145
1146	de->next_offset = e->next_offset - (origsize - *size);
1147	for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1148	if ((unsigned char *)de - base < newinfo->hook_entry[h])
1149	newinfo->hook_entry[h] -= origsize - *size;
1150	if ((unsigned char *)de - base < newinfo->underflow[h])
1151	newinfo->underflow[h] -= origsize - *size;
1152	}
1153	}
1154
1155	static int translate_compat_table(struct net *net,
1156	struct xt_table_info **pinfo,
1157	void **pentry0,
1158	const struct compat_arpt_replace *compatr)
1159	{
1160	unsigned int i, j;
1161	struct xt_table_info *newinfo, *info;
1162	void *pos, *entry0, *entry1;
1163	struct compat_arpt_entry *iter0;
1164	struct arpt_replace repl;
1165	unsigned int size;
1166	int ret;
1167
1168	info = *pinfo;
1169	entry0 = *pentry0;
1170	size = compatr->size;
1171	info->number = compatr->num_entries;
1172
1173	j = 0;
1174	xt_compat_lock(af: NFPROTO_ARP);
1175	ret = xt_compat_init_offsets(af: NFPROTO_ARP, number: compatr->num_entries);
1176	if (ret)
1177	goto out_unlock;
1178	/* Walk through entries, checking offsets. */
1179	xt_entry_foreach(iter0, entry0, compatr->size) {
1180	ret = check_compat_entry_size_and_hooks(e: iter0, newinfo: info, size: &size,
1181	base: entry0,
1182	limit: entry0 + compatr->size);
1183	if (ret != 0)
1184	goto out_unlock;
1185	++j;
1186	}
1187
1188	ret = -EINVAL;
1189	if (j != compatr->num_entries)
1190	goto out_unlock;
1191
1192	ret = -ENOMEM;
1193	newinfo = xt_alloc_table_info(size);
1194	if (!newinfo)
1195	goto out_unlock;
1196
1197	memset(newinfo->entries, 0, size);
1198
1199	newinfo->number = compatr->num_entries;
1200	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1201	newinfo->hook_entry[i] = compatr->hook_entry[i];
1202	newinfo->underflow[i] = compatr->underflow[i];
1203	}
1204	entry1 = newinfo->entries;
1205	pos = entry1;
1206	size = compatr->size;
1207	xt_entry_foreach(iter0, entry0, compatr->size)
1208	compat_copy_entry_from_user(e: iter0, dstptr: &pos, size: &size,
1209	newinfo, base: entry1);
1210
1211	/* all module references in entry0 are now gone */
1212
1213	xt_compat_flush_offsets(af: NFPROTO_ARP);
1214	xt_compat_unlock(af: NFPROTO_ARP);
1215
1216	memcpy(&repl, compatr, sizeof(*compatr));
1217
1218	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1219	repl.hook_entry[i] = newinfo->hook_entry[i];
1220	repl.underflow[i] = newinfo->underflow[i];
1221	}
1222
1223	repl.num_counters = 0;
1224	repl.counters = NULL;
1225	repl.size = newinfo->size;
1226	ret = translate_table(net, newinfo, entry0: entry1, repl: &repl);
1227	if (ret)
1228	goto free_newinfo;
1229
1230	*pinfo = newinfo;
1231	*pentry0 = entry1;
1232	xt_free_table_info(info);
1233	return 0;
1234
1235	free_newinfo:
1236	xt_free_table_info(info: newinfo);
1237	return ret;
1238	out_unlock:
1239	xt_compat_flush_offsets(af: NFPROTO_ARP);
1240	xt_compat_unlock(af: NFPROTO_ARP);
1241	xt_entry_foreach(iter0, entry0, compatr->size) {
1242	if (j-- == 0)
1243	break;
1244	compat_release_entry(e: iter0);
1245	}
1246	return ret;
1247	}
1248
1249	static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
1250	{
1251	int ret;
1252	struct compat_arpt_replace tmp;
1253	struct xt_table_info *newinfo;
1254	void *loc_cpu_entry;
1255	struct arpt_entry *iter;
1256
1257	if (copy_from_sockptr(dst: &tmp, src: arg, size: sizeof(tmp)) != 0)
1258	return -EFAULT;
1259
1260	/* overflow check */
1261	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1262	return -ENOMEM;
1263	if (tmp.num_counters == 0)
1264	return -EINVAL;
1265
1266	tmp.name[sizeof(tmp.name)-1] = 0;
1267
1268	newinfo = xt_alloc_table_info(size: tmp.size);
1269	if (!newinfo)
1270	return -ENOMEM;
1271
1272	loc_cpu_entry = newinfo->entries;
1273	if (copy_from_sockptr_offset(dst: loc_cpu_entry, src: arg, offset: sizeof(tmp),
1274	size: tmp.size) != 0) {
1275	ret = -EFAULT;
1276	goto free_newinfo;
1277	}
1278
1279	ret = translate_compat_table(net, pinfo: &newinfo, pentry0: &loc_cpu_entry, compatr: &tmp);
1280	if (ret != 0)
1281	goto free_newinfo;
1282
1283	ret = __do_replace(net, name: tmp.name, valid_hooks: tmp.valid_hooks, newinfo,
1284	num_counters: tmp.num_counters, counters_ptr: compat_ptr(uptr: tmp.counters));
1285	if (ret)
1286	goto free_newinfo_untrans;
1287	return 0;
1288
1289	free_newinfo_untrans:
1290	xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1291	cleanup_entry(e: iter, net);
1292	free_newinfo:
1293	xt_free_table_info(info: newinfo);
1294	return ret;
1295	}
1296
1297	static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1298	compat_uint_t *size,
1299	struct xt_counters *counters,
1300	unsigned int i)
1301	{
1302	struct xt_entry_target *t;
1303	struct compat_arpt_entry __user *ce;
1304	u_int16_t target_offset, next_offset;
1305	compat_uint_t origsize;
1306	int ret;
1307
1308	origsize = *size;
1309	ce = *dstptr;
1310	if (copy_to_user(to: ce, from: e, n: sizeof(struct arpt_entry)) != 0 ||
1311	copy_to_user(to: &ce->counters, from: &counters[i],
1312	n: sizeof(counters[i])) != 0)
1313	return -EFAULT;
1314
1315	*dstptr += sizeof(struct compat_arpt_entry);
1316	*size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1317
1318	target_offset = e->target_offset - (origsize - *size);
1319
1320	t = arpt_get_target(e);
1321	ret = xt_compat_target_to_user(t, dstptr, size);
1322	if (ret)
1323	return ret;
1324	next_offset = e->next_offset - (origsize - *size);
1325	if (put_user(target_offset, &ce->target_offset) != 0 ||
1326	put_user(next_offset, &ce->next_offset) != 0)
1327	return -EFAULT;
1328	return 0;
1329	}
1330
1331	static int compat_copy_entries_to_user(unsigned int total_size,
1332	struct xt_table *table,
1333	void __user *userptr)
1334	{
1335	struct xt_counters *counters;
1336	const struct xt_table_info *private = table->private;
1337	void __user *pos;
1338	unsigned int size;
1339	int ret = 0;
1340	unsigned int i = 0;
1341	struct arpt_entry *iter;
1342
1343	counters = alloc_counters(table);
1344	if (IS_ERR(ptr: counters))
1345	return PTR_ERR(ptr: counters);
1346
1347	pos = userptr;
1348	size = total_size;
1349	xt_entry_foreach(iter, private->entries, total_size) {
1350	ret = compat_copy_entry_to_user(e: iter, dstptr: &pos,
1351	size: &size, counters, i: i++);
1352	if (ret != 0)
1353	break;
1354	}
1355	vfree(addr: counters);
1356	return ret;
1357	}
1358
1359	struct compat_arpt_get_entries {
1360	char name[XT_TABLE_MAXNAMELEN];
1361	compat_uint_t size;
1362	struct compat_arpt_entry entrytable[];
1363	};
1364
1365	static int compat_get_entries(struct net *net,
1366	struct compat_arpt_get_entries __user *uptr,
1367	int *len)
1368	{
1369	int ret;
1370	struct compat_arpt_get_entries get;
1371	struct xt_table *t;
1372
1373	if (*len < sizeof(get))
1374	return -EINVAL;
1375	if (copy_from_user(to: &get, from: uptr, n: sizeof(get)) != 0)
1376	return -EFAULT;
1377	if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1378	return -EINVAL;
1379
1380	get.name[sizeof(get.name) - 1] = '\0';
1381
1382	xt_compat_lock(af: NFPROTO_ARP);
1383	t = xt_find_table_lock(net, af: NFPROTO_ARP, name: get.name);
1384	if (!IS_ERR(ptr: t)) {
1385	const struct xt_table_info *private = t->private;
1386	struct xt_table_info info;
1387
1388	ret = compat_table_info(info: private, newinfo: &info);
1389	if (!ret && get.size == info.size) {
1390	ret = compat_copy_entries_to_user(total_size: private->size,
1391	table: t, userptr: uptr->entrytable);
1392	} else if (!ret)
1393	ret = -EAGAIN;
1394
1395	xt_compat_flush_offsets(af: NFPROTO_ARP);
1396	module_put(module: t->me);
1397	xt_table_unlock(t);
1398	} else
1399	ret = PTR_ERR(ptr: t);
1400
1401	xt_compat_unlock(af: NFPROTO_ARP);
1402	return ret;
1403	}
1404	#endif
1405
1406	static int do_arpt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
1407	unsigned int len)
1408	{
1409	int ret;
1410
1411	if (!ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_ADMIN))
1412	return -EPERM;
1413
1414	switch (cmd) {
1415	case ARPT_SO_SET_REPLACE:
1416	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1417	if (in_compat_syscall())
1418	ret = compat_do_replace(net: sock_net(sk), arg, len);
1419	else
1420	#endif
1421	ret = do_replace(net: sock_net(sk), arg, len);
1422	break;
1423
1424	case ARPT_SO_SET_ADD_COUNTERS:
1425	ret = do_add_counters(net: sock_net(sk), arg, len);
1426	break;
1427
1428	default:
1429	ret = -EINVAL;
1430	}
1431
1432	return ret;
1433	}
1434
1435	static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1436	{
1437	int ret;
1438
1439	if (!ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_ADMIN))
1440	return -EPERM;
1441
1442	switch (cmd) {
1443	case ARPT_SO_GET_INFO:
1444	ret = get_info(net: sock_net(sk), user, len);
1445	break;
1446
1447	case ARPT_SO_GET_ENTRIES:
1448	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1449	if (in_compat_syscall())
1450	ret = compat_get_entries(net: sock_net(sk), uptr: user, len);
1451	else
1452	#endif
1453	ret = get_entries(net: sock_net(sk), uptr: user, len);
1454	break;
1455
1456	case ARPT_SO_GET_REVISION_TARGET: {
1457	struct xt_get_revision rev;
1458
1459	if (*len != sizeof(rev)) {
1460	ret = -EINVAL;
1461	break;
1462	}
1463	if (copy_from_user(to: &rev, from: user, n: sizeof(rev)) != 0) {
1464	ret = -EFAULT;
1465	break;
1466	}
1467	rev.name[sizeof(rev.name)-1] = 0;
1468
1469	try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1470	rev.revision, 1, &ret),
1471	"arpt_%s", rev.name);
1472	break;
1473	}
1474
1475	default:
1476	ret = -EINVAL;
1477	}
1478
1479	return ret;
1480	}
1481
1482	static void __arpt_unregister_table(struct net *net, struct xt_table *table)
1483	{
1484	struct xt_table_info *private;
1485	void *loc_cpu_entry;
1486	struct module *table_owner = table->me;
1487	struct arpt_entry *iter;
1488
1489	private = xt_unregister_table(table);
1490
1491	/* Decrease module usage counts and free resources */
1492	loc_cpu_entry = private->entries;
1493	xt_entry_foreach(iter, loc_cpu_entry, private->size)
1494	cleanup_entry(e: iter, net);
1495	if (private->number > private->initial_entries)
1496	module_put(module: table_owner);
1497	xt_free_table_info(info: private);
1498	}
1499
1500	int arpt_register_table(struct net *net,
1501	const struct xt_table *table,
1502	const struct arpt_replace *repl,
1503	const struct nf_hook_ops *template_ops)
1504	{
1505	struct nf_hook_ops *ops;
1506	unsigned int num_ops;
1507	int ret, i;
1508	struct xt_table_info *newinfo;
1509	struct xt_table_info bootstrap = {0};
1510	void *loc_cpu_entry;
1511	struct xt_table *new_table;
1512
1513	newinfo = xt_alloc_table_info(size: repl->size);
1514	if (!newinfo)
1515	return -ENOMEM;
1516
1517	loc_cpu_entry = newinfo->entries;
1518	memcpy(loc_cpu_entry, repl->entries, repl->size);
1519
1520	ret = translate_table(net, newinfo, entry0: loc_cpu_entry, repl);
1521	if (ret != 0) {
1522	xt_free_table_info(info: newinfo);
1523	return ret;
1524	}
1525
1526	new_table = xt_register_table(net, table, bootstrap: &bootstrap, newinfo);
1527	if (IS_ERR(ptr: new_table)) {
1528	struct arpt_entry *iter;
1529
1530	xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1531	cleanup_entry(e: iter, net);
1532	xt_free_table_info(info: newinfo);
1533	return PTR_ERR(ptr: new_table);
1534	}
1535
1536	num_ops = hweight32(table->valid_hooks);
1537	if (num_ops == 0) {
1538	ret = -EINVAL;
1539	goto out_free;
1540	}
1541
1542	ops = kmemdup(p: template_ops, size: sizeof(*ops) * num_ops, GFP_KERNEL);
1543	if (!ops) {
1544	ret = -ENOMEM;
1545	goto out_free;
1546	}
1547
1548	for (i = 0; i < num_ops; i++)
1549	ops[i].priv = new_table;
1550
1551	new_table->ops = ops;
1552
1553	ret = nf_register_net_hooks(net, reg: ops, n: num_ops);
1554	if (ret != 0)
1555	goto out_free;
1556
1557	return ret;
1558
1559	out_free:
1560	__arpt_unregister_table(net, table: new_table);
1561	return ret;
1562	}
1563
1564	void arpt_unregister_table_pre_exit(struct net *net, const char *name)
1565	{
1566	struct xt_table *table = xt_find_table(net, af: NFPROTO_ARP, name);
1567
1568	if (table)
1569	nf_unregister_net_hooks(net, reg: table->ops, hweight32(table->valid_hooks));
1570	}
1571	EXPORT_SYMBOL(arpt_unregister_table_pre_exit);
1572
1573	void arpt_unregister_table(struct net *net, const char *name)
1574	{
1575	struct xt_table *table = xt_find_table(net, af: NFPROTO_ARP, name);
1576
1577	if (table)
1578	__arpt_unregister_table(net, table);
1579	}
1580
1581	/* The built-in targets: standard (NULL) and error. */
1582	static struct xt_target arpt_builtin_tg[] __read_mostly = {
1583	{
1584	.name = XT_STANDARD_TARGET,
1585	.targetsize = sizeof(int),
1586	.family = NFPROTO_ARP,
1587	#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1588	.compatsize = sizeof(compat_int_t),
1589	.compat_from_user = compat_standard_from_user,
1590	.compat_to_user = compat_standard_to_user,
1591	#endif
1592	},
1593	{
1594	.name = XT_ERROR_TARGET,
1595	.target = arpt_error,
1596	.targetsize = XT_FUNCTION_MAXNAMELEN,
1597	.family = NFPROTO_ARP,
1598	},
1599	};
1600
1601	static struct nf_sockopt_ops arpt_sockopts = {
1602	.pf = PF_INET,
1603	.set_optmin = ARPT_BASE_CTL,
1604	.set_optmax = ARPT_SO_SET_MAX+1,
1605	.set = do_arpt_set_ctl,
1606	.get_optmin = ARPT_BASE_CTL,
1607	.get_optmax = ARPT_SO_GET_MAX+1,
1608	.get = do_arpt_get_ctl,
1609	.owner = THIS_MODULE,
1610	};
1611
1612	static int __net_init arp_tables_net_init(struct net *net)
1613	{
1614	return xt_proto_init(net, af: NFPROTO_ARP);
1615	}
1616
1617	static void __net_exit arp_tables_net_exit(struct net *net)
1618	{
1619	xt_proto_fini(net, af: NFPROTO_ARP);
1620	}
1621
1622	static struct pernet_operations arp_tables_net_ops = {
1623	.init = arp_tables_net_init,
1624	.exit = arp_tables_net_exit,
1625	};
1626
1627	static int __init arp_tables_init(void)
1628	{
1629	int ret;
1630
1631	ret = register_pernet_subsys(&arp_tables_net_ops);
1632	if (ret < 0)
1633	goto err1;
1634
1635	/* No one else will be downing sem now, so we won't sleep */
1636	ret = xt_register_targets(target: arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1637	if (ret < 0)
1638	goto err2;
1639
1640	/* Register setsockopt */
1641	ret = nf_register_sockopt(reg: &arpt_sockopts);
1642	if (ret < 0)
1643	goto err4;
1644
1645	return 0;
1646
1647	err4:
1648	xt_unregister_targets(target: arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1649	err2:
1650	unregister_pernet_subsys(&arp_tables_net_ops);
1651	err1:
1652	return ret;
1653	}
1654
1655	static void __exit arp_tables_fini(void)
1656	{
1657	nf_unregister_sockopt(reg: &arpt_sockopts);
1658	xt_unregister_targets(target: arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1659	unregister_pernet_subsys(&arp_tables_net_ops);
1660	}
1661
1662	EXPORT_SYMBOL(arpt_register_table);
1663	EXPORT_SYMBOL(arpt_unregister_table);
1664	EXPORT_SYMBOL(arpt_do_table);
1665
1666	module_init(arp_tables_init);
1667	module_exit(arp_tables_fini);
1668