1/*
2 * Packet matching code for ARP packets.
3 *
4 * Based heavily, if not almost entirely, upon ip_tables.c framework.
5 *
6 * Some ARP specific bits are:
7 *
8 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
9 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
10 *
11 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13#include <linux/kernel.h>
14#include <linux/skbuff.h>
15#include <linux/netdevice.h>
16#include <linux/capability.h>
17#include <linux/if_arp.h>
18#include <linux/kmod.h>
19#include <linux/vmalloc.h>
20#include <linux/proc_fs.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/mutex.h>
24#include <linux/err.h>
25#include <net/compat.h>
26#include <net/sock.h>
27#include <linux/uaccess.h>
28
29#include <linux/netfilter/x_tables.h>
30#include <linux/netfilter_arp/arp_tables.h>
31#include "../../netfilter/xt_repldata.h"
32
33MODULE_LICENSE("GPL");
34MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
35MODULE_DESCRIPTION("arptables core");
36
37void *arpt_alloc_initial_table(const struct xt_table *info)
38{
39 return xt_alloc_initial_table(arpt, ARPT);
40}
41EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
42
43static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
44 const char *hdr_addr, int len)
45{
46 int i, ret;
47
48 if (len > ARPT_DEV_ADDR_LEN_MAX)
49 len = ARPT_DEV_ADDR_LEN_MAX;
50
51 ret = 0;
52 for (i = 0; i < len; i++)
53 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
54
55 return ret != 0;
56}
57
58/*
59 * Unfortunately, _b and _mask are not aligned to an int (or long int)
60 * Some arches dont care, unrolling the loop is a win on them.
61 * For other arches, we only have a 16bit alignement.
62 */
63static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
64{
65#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
66 unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
67#else
68 unsigned long ret = 0;
69 const u16 *a = (const u16 *)_a;
70 const u16 *b = (const u16 *)_b;
71 const u16 *mask = (const u16 *)_mask;
72 int i;
73
74 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
75 ret |= (a[i] ^ b[i]) & mask[i];
76#endif
77 return ret;
78}
79
80/* Returns whether packet matches rule or not. */
81static inline int arp_packet_match(const struct arphdr *arphdr,
82 struct net_device *dev,
83 const char *indev,
84 const char *outdev,
85 const struct arpt_arp *arpinfo)
86{
87 const char *arpptr = (char *)(arphdr + 1);
88 const char *src_devaddr, *tgt_devaddr;
89 __be32 src_ipaddr, tgt_ipaddr;
90 long ret;
91
92 if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
93 (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
94 return 0;
95
96 if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
97 (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
98 return 0;
99
100 if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
101 (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
102 return 0;
103
104 if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
105 (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
106 return 0;
107
108 src_devaddr = arpptr;
109 arpptr += dev->addr_len;
110 memcpy(&src_ipaddr, arpptr, sizeof(u32));
111 arpptr += sizeof(u32);
112 tgt_devaddr = arpptr;
113 arpptr += dev->addr_len;
114 memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
115
116 if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
117 arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
118 dev->addr_len)) ||
119 NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
120 arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
121 dev->addr_len)))
122 return 0;
123
124 if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
125 (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
126 NF_INVF(arpinfo, ARPT_INV_TGTIP,
127 (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
128 return 0;
129
130 /* Look for ifname matches. */
131 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
132
133 if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
134 return 0;
135
136 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
137
138 if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
139 return 0;
140
141 return 1;
142}
143
144static inline int arp_checkentry(const struct arpt_arp *arp)
145{
146 if (arp->flags & ~ARPT_F_MASK)
147 return 0;
148 if (arp->invflags & ~ARPT_INV_MASK)
149 return 0;
150
151 return 1;
152}
153
154static unsigned int
155arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
156{
157 net_err_ratelimited("arp_tables: error: '%s'\n",
158 (const char *)par->targinfo);
159
160 return NF_DROP;
161}
162
163static inline const struct xt_entry_target *
164arpt_get_target_c(const struct arpt_entry *e)
165{
166 return arpt_get_target((struct arpt_entry *)e);
167}
168
169static inline struct arpt_entry *
170get_entry(const void *base, unsigned int offset)
171{
172 return (struct arpt_entry *)(base + offset);
173}
174
175static inline
176struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
177{
178 return (void *)entry + entry->next_offset;
179}
180
181unsigned int arpt_do_table(struct sk_buff *skb,
182 const struct nf_hook_state *state,
183 struct xt_table *table)
184{
185 unsigned int hook = state->hook;
186 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
187 unsigned int verdict = NF_DROP;
188 const struct arphdr *arp;
189 struct arpt_entry *e, **jumpstack;
190 const char *indev, *outdev;
191 const void *table_base;
192 unsigned int cpu, stackidx = 0;
193 const struct xt_table_info *private;
194 struct xt_action_param acpar;
195 unsigned int addend;
196
197 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
198 return NF_DROP;
199
200 indev = state->in ? state->in->name : nulldevname;
201 outdev = state->out ? state->out->name : nulldevname;
202
203 local_bh_disable();
204 addend = xt_write_recseq_begin();
205 private = READ_ONCE(table->private); /* Address dependency. */
206 cpu = smp_processor_id();
207 table_base = private->entries;
208 jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
209
210 /* No TEE support for arptables, so no need to switch to alternate
211 * stack. All targets that reenter must return absolute verdicts.
212 */
213 e = get_entry(table_base, private->hook_entry[hook]);
214
215 acpar.state = state;
216 acpar.hotdrop = false;
217
218 arp = arp_hdr(skb);
219 do {
220 const struct xt_entry_target *t;
221 struct xt_counters *counter;
222
223 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
224 e = arpt_next_entry(e);
225 continue;
226 }
227
228 counter = xt_get_this_cpu_counter(&e->counters);
229 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
230
231 t = arpt_get_target_c(e);
232
233 /* Standard target? */
234 if (!t->u.kernel.target->target) {
235 int v;
236
237 v = ((struct xt_standard_target *)t)->verdict;
238 if (v < 0) {
239 /* Pop from stack? */
240 if (v != XT_RETURN) {
241 verdict = (unsigned int)(-v) - 1;
242 break;
243 }
244 if (stackidx == 0) {
245 e = get_entry(table_base,
246 private->underflow[hook]);
247 } else {
248 e = jumpstack[--stackidx];
249 e = arpt_next_entry(e);
250 }
251 continue;
252 }
253 if (table_base + v
254 != arpt_next_entry(e)) {
255 if (unlikely(stackidx >= private->stacksize)) {
256 verdict = NF_DROP;
257 break;
258 }
259 jumpstack[stackidx++] = e;
260 }
261
262 e = get_entry(table_base, v);
263 continue;
264 }
265
266 acpar.target = t->u.kernel.target;
267 acpar.targinfo = t->data;
268 verdict = t->u.kernel.target->target(skb, &acpar);
269
270 if (verdict == XT_CONTINUE) {
271 /* Target might have changed stuff. */
272 arp = arp_hdr(skb);
273 e = arpt_next_entry(e);
274 } else {
275 /* Verdict */
276 break;
277 }
278 } while (!acpar.hotdrop);
279 xt_write_recseq_end(addend);
280 local_bh_enable();
281
282 if (acpar.hotdrop)
283 return NF_DROP;
284 else
285 return verdict;
286}
287
288/* All zeroes == unconditional rule. */
289static inline bool unconditional(const struct arpt_entry *e)
290{
291 static const struct arpt_arp uncond;
292
293 return e->target_offset == sizeof(struct arpt_entry) &&
294 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
295}
296
297/* Figures out from what hook each rule can be called: returns 0 if
298 * there are loops. Puts hook bitmask in comefrom.
299 */
300static int mark_source_chains(const struct xt_table_info *newinfo,
301 unsigned int valid_hooks, void *entry0,
302 unsigned int *offsets)
303{
304 unsigned int hook;
305
306 /* No recursion; use packet counter to save back ptrs (reset
307 * to 0 as we leave), and comefrom to save source hook bitmask.
308 */
309 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
310 unsigned int pos = newinfo->hook_entry[hook];
311 struct arpt_entry *e = entry0 + pos;
312
313 if (!(valid_hooks & (1 << hook)))
314 continue;
315
316 /* Set initial back pointer. */
317 e->counters.pcnt = pos;
318
319 for (;;) {
320 const struct xt_standard_target *t
321 = (void *)arpt_get_target_c(e);
322 int visited = e->comefrom & (1 << hook);
323
324 if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
325 return 0;
326
327 e->comefrom
328 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
329
330 /* Unconditional return/END. */
331 if ((unconditional(e) &&
332 (strcmp(t->target.u.user.name,
333 XT_STANDARD_TARGET) == 0) &&
334 t->verdict < 0) || visited) {
335 unsigned int oldpos, size;
336
337 /* Return: backtrack through the last
338 * big jump.
339 */
340 do {
341 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
342 oldpos = pos;
343 pos = e->counters.pcnt;
344 e->counters.pcnt = 0;
345
346 /* We're at the start. */
347 if (pos == oldpos)
348 goto next;
349
350 e = entry0 + pos;
351 } while (oldpos == pos + e->next_offset);
352
353 /* Move along one */
354 size = e->next_offset;
355 e = entry0 + pos + size;
356 if (pos + size >= newinfo->size)
357 return 0;
358 e->counters.pcnt = pos;
359 pos += size;
360 } else {
361 int newpos = t->verdict;
362
363 if (strcmp(t->target.u.user.name,
364 XT_STANDARD_TARGET) == 0 &&
365 newpos >= 0) {
366 /* This a jump; chase it. */
367 if (!xt_find_jump_offset(offsets, newpos,
368 newinfo->number))
369 return 0;
370 } else {
371 /* ... this is a fallthru */
372 newpos = pos + e->next_offset;
373 if (newpos >= newinfo->size)
374 return 0;
375 }
376 e = entry0 + newpos;
377 e->counters.pcnt = pos;
378 pos = newpos;
379 }
380 }
381next: ;
382 }
383 return 1;
384}
385
386static inline int check_target(struct arpt_entry *e, const char *name)
387{
388 struct xt_entry_target *t = arpt_get_target(e);
389 struct xt_tgchk_param par = {
390 .table = name,
391 .entryinfo = e,
392 .target = t->u.kernel.target,
393 .targinfo = t->data,
394 .hook_mask = e->comefrom,
395 .family = NFPROTO_ARP,
396 };
397
398 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
399}
400
401static inline int
402find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
403 struct xt_percpu_counter_alloc_state *alloc_state)
404{
405 struct xt_entry_target *t;
406 struct xt_target *target;
407 int ret;
408
409 if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
410 return -ENOMEM;
411
412 t = arpt_get_target(e);
413 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
414 t->u.user.revision);
415 if (IS_ERR(target)) {
416 ret = PTR_ERR(target);
417 goto out;
418 }
419 t->u.kernel.target = target;
420
421 ret = check_target(e, name);
422 if (ret)
423 goto err;
424 return 0;
425err:
426 module_put(t->u.kernel.target->me);
427out:
428 xt_percpu_counter_free(&e->counters);
429
430 return ret;
431}
432
433static bool check_underflow(const struct arpt_entry *e)
434{
435 const struct xt_entry_target *t;
436 unsigned int verdict;
437
438 if (!unconditional(e))
439 return false;
440 t = arpt_get_target_c(e);
441 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
442 return false;
443 verdict = ((struct xt_standard_target *)t)->verdict;
444 verdict = -verdict - 1;
445 return verdict == NF_DROP || verdict == NF_ACCEPT;
446}
447
448static inline int check_entry_size_and_hooks(struct arpt_entry *e,
449 struct xt_table_info *newinfo,
450 const unsigned char *base,
451 const unsigned char *limit,
452 const unsigned int *hook_entries,
453 const unsigned int *underflows,
454 unsigned int valid_hooks)
455{
456 unsigned int h;
457 int err;
458
459 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
460 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
461 (unsigned char *)e + e->next_offset > limit)
462 return -EINVAL;
463
464 if (e->next_offset
465 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
466 return -EINVAL;
467
468 if (!arp_checkentry(&e->arp))
469 return -EINVAL;
470
471 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
472 e->next_offset);
473 if (err)
474 return err;
475
476 /* Check hooks & underflows */
477 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
478 if (!(valid_hooks & (1 << h)))
479 continue;
480 if ((unsigned char *)e - base == hook_entries[h])
481 newinfo->hook_entry[h] = hook_entries[h];
482 if ((unsigned char *)e - base == underflows[h]) {
483 if (!check_underflow(e))
484 return -EINVAL;
485
486 newinfo->underflow[h] = underflows[h];
487 }
488 }
489
490 /* Clear counters and comefrom */
491 e->counters = ((struct xt_counters) { 0, 0 });
492 e->comefrom = 0;
493 return 0;
494}
495
496static inline void cleanup_entry(struct arpt_entry *e)
497{
498 struct xt_tgdtor_param par;
499 struct xt_entry_target *t;
500
501 t = arpt_get_target(e);
502 par.target = t->u.kernel.target;
503 par.targinfo = t->data;
504 par.family = NFPROTO_ARP;
505 if (par.target->destroy != NULL)
506 par.target->destroy(&par);
507 module_put(par.target->me);
508 xt_percpu_counter_free(&e->counters);
509}
510
511/* Checks and translates the user-supplied table segment (held in
512 * newinfo).
513 */
514static int translate_table(struct xt_table_info *newinfo, void *entry0,
515 const struct arpt_replace *repl)
516{
517 struct xt_percpu_counter_alloc_state alloc_state = { 0 };
518 struct arpt_entry *iter;
519 unsigned int *offsets;
520 unsigned int i;
521 int ret = 0;
522
523 newinfo->size = repl->size;
524 newinfo->number = repl->num_entries;
525
526 /* Init all hooks to impossible value. */
527 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
528 newinfo->hook_entry[i] = 0xFFFFFFFF;
529 newinfo->underflow[i] = 0xFFFFFFFF;
530 }
531
532 offsets = xt_alloc_entry_offsets(newinfo->number);
533 if (!offsets)
534 return -ENOMEM;
535 i = 0;
536
537 /* Walk through entries, checking offsets. */
538 xt_entry_foreach(iter, entry0, newinfo->size) {
539 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
540 entry0 + repl->size,
541 repl->hook_entry,
542 repl->underflow,
543 repl->valid_hooks);
544 if (ret != 0)
545 goto out_free;
546 if (i < repl->num_entries)
547 offsets[i] = (void *)iter - entry0;
548 ++i;
549 if (strcmp(arpt_get_target(iter)->u.user.name,
550 XT_ERROR_TARGET) == 0)
551 ++newinfo->stacksize;
552 }
553
554 ret = -EINVAL;
555 if (i != repl->num_entries)
556 goto out_free;
557
558 ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
559 if (ret)
560 goto out_free;
561
562 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
563 ret = -ELOOP;
564 goto out_free;
565 }
566 kvfree(offsets);
567
568 /* Finally, each sanity check must pass */
569 i = 0;
570 xt_entry_foreach(iter, entry0, newinfo->size) {
571 ret = find_check_entry(iter, repl->name, repl->size,
572 &alloc_state);
573 if (ret != 0)
574 break;
575 ++i;
576 }
577
578 if (ret != 0) {
579 xt_entry_foreach(iter, entry0, newinfo->size) {
580 if (i-- == 0)
581 break;
582 cleanup_entry(iter);
583 }
584 return ret;
585 }
586
587 return ret;
588 out_free:
589 kvfree(offsets);
590 return ret;
591}
592
593static void get_counters(const struct xt_table_info *t,
594 struct xt_counters counters[])
595{
596 struct arpt_entry *iter;
597 unsigned int cpu;
598 unsigned int i;
599
600 for_each_possible_cpu(cpu) {
601 seqcount_t *s = &per_cpu(xt_recseq, cpu);
602
603 i = 0;
604 xt_entry_foreach(iter, t->entries, t->size) {
605 struct xt_counters *tmp;
606 u64 bcnt, pcnt;
607 unsigned int start;
608
609 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
610 do {
611 start = read_seqcount_begin(s);
612 bcnt = tmp->bcnt;
613 pcnt = tmp->pcnt;
614 } while (read_seqcount_retry(s, start));
615
616 ADD_COUNTER(counters[i], bcnt, pcnt);
617 ++i;
618 cond_resched();
619 }
620 }
621}
622
623static void get_old_counters(const struct xt_table_info *t,
624 struct xt_counters counters[])
625{
626 struct arpt_entry *iter;
627 unsigned int cpu, i;
628
629 for_each_possible_cpu(cpu) {
630 i = 0;
631 xt_entry_foreach(iter, t->entries, t->size) {
632 struct xt_counters *tmp;
633
634 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
635 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
636 ++i;
637 }
638 cond_resched();
639 }
640}
641
642static struct xt_counters *alloc_counters(const struct xt_table *table)
643{
644 unsigned int countersize;
645 struct xt_counters *counters;
646 const struct xt_table_info *private = table->private;
647
648 /* We need atomic snapshot of counters: rest doesn't change
649 * (other than comefrom, which userspace doesn't care
650 * about).
651 */
652 countersize = sizeof(struct xt_counters) * private->number;
653 counters = vzalloc(countersize);
654
655 if (counters == NULL)
656 return ERR_PTR(-ENOMEM);
657
658 get_counters(private, counters);
659
660 return counters;
661}
662
663static int copy_entries_to_user(unsigned int total_size,
664 const struct xt_table *table,
665 void __user *userptr)
666{
667 unsigned int off, num;
668 const struct arpt_entry *e;
669 struct xt_counters *counters;
670 struct xt_table_info *private = table->private;
671 int ret = 0;
672 void *loc_cpu_entry;
673
674 counters = alloc_counters(table);
675 if (IS_ERR(counters))
676 return PTR_ERR(counters);
677
678 loc_cpu_entry = private->entries;
679
680 /* FIXME: use iterator macros --RR */
681 /* ... then go back and fix counters and names */
682 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
683 const struct xt_entry_target *t;
684
685 e = loc_cpu_entry + off;
686 if (copy_to_user(userptr + off, e, sizeof(*e))) {
687 ret = -EFAULT;
688 goto free_counters;
689 }
690 if (copy_to_user(userptr + off
691 + offsetof(struct arpt_entry, counters),
692 &counters[num],
693 sizeof(counters[num])) != 0) {
694 ret = -EFAULT;
695 goto free_counters;
696 }
697
698 t = arpt_get_target_c(e);
699 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
700 ret = -EFAULT;
701 goto free_counters;
702 }
703 }
704
705 free_counters:
706 vfree(counters);
707 return ret;
708}
709
710#ifdef CONFIG_COMPAT
711static void compat_standard_from_user(void *dst, const void *src)
712{
713 int v = *(compat_int_t *)src;
714
715 if (v > 0)
716 v += xt_compat_calc_jump(NFPROTO_ARP, v);
717 memcpy(dst, &v, sizeof(v));
718}
719
720static int compat_standard_to_user(void __user *dst, const void *src)
721{
722 compat_int_t cv = *(int *)src;
723
724 if (cv > 0)
725 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
726 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
727}
728
729static int compat_calc_entry(const struct arpt_entry *e,
730 const struct xt_table_info *info,
731 const void *base, struct xt_table_info *newinfo)
732{
733 const struct xt_entry_target *t;
734 unsigned int entry_offset;
735 int off, i, ret;
736
737 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
738 entry_offset = (void *)e - base;
739
740 t = arpt_get_target_c(e);
741 off += xt_compat_target_offset(t->u.kernel.target);
742 newinfo->size -= off;
743 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
744 if (ret)
745 return ret;
746
747 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
748 if (info->hook_entry[i] &&
749 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
750 newinfo->hook_entry[i] -= off;
751 if (info->underflow[i] &&
752 (e < (struct arpt_entry *)(base + info->underflow[i])))
753 newinfo->underflow[i] -= off;
754 }
755 return 0;
756}
757
758static int compat_table_info(const struct xt_table_info *info,
759 struct xt_table_info *newinfo)
760{
761 struct arpt_entry *iter;
762 const void *loc_cpu_entry;
763 int ret;
764
765 if (!newinfo || !info)
766 return -EINVAL;
767
768 /* we dont care about newinfo->entries */
769 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
770 newinfo->initial_entries = 0;
771 loc_cpu_entry = info->entries;
772 ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
773 if (ret)
774 return ret;
775 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
776 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
777 if (ret != 0)
778 return ret;
779 }
780 return 0;
781}
782#endif
783
784static int get_info(struct net *net, void __user *user,
785 const int *len, int compat)
786{
787 char name[XT_TABLE_MAXNAMELEN];
788 struct xt_table *t;
789 int ret;
790
791 if (*len != sizeof(struct arpt_getinfo))
792 return -EINVAL;
793
794 if (copy_from_user(name, user, sizeof(name)) != 0)
795 return -EFAULT;
796
797 name[XT_TABLE_MAXNAMELEN-1] = '\0';
798#ifdef CONFIG_COMPAT
799 if (compat)
800 xt_compat_lock(NFPROTO_ARP);
801#endif
802 t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
803 if (!IS_ERR(t)) {
804 struct arpt_getinfo info;
805 const struct xt_table_info *private = t->private;
806#ifdef CONFIG_COMPAT
807 struct xt_table_info tmp;
808
809 if (compat) {
810 ret = compat_table_info(private, &tmp);
811 xt_compat_flush_offsets(NFPROTO_ARP);
812 private = &tmp;
813 }
814#endif
815 memset(&info, 0, sizeof(info));
816 info.valid_hooks = t->valid_hooks;
817 memcpy(info.hook_entry, private->hook_entry,
818 sizeof(info.hook_entry));
819 memcpy(info.underflow, private->underflow,
820 sizeof(info.underflow));
821 info.num_entries = private->number;
822 info.size = private->size;
823 strcpy(info.name, name);
824
825 if (copy_to_user(user, &info, *len) != 0)
826 ret = -EFAULT;
827 else
828 ret = 0;
829 xt_table_unlock(t);
830 module_put(t->me);
831 } else
832 ret = PTR_ERR(t);
833#ifdef CONFIG_COMPAT
834 if (compat)
835 xt_compat_unlock(NFPROTO_ARP);
836#endif
837 return ret;
838}
839
840static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
841 const int *len)
842{
843 int ret;
844 struct arpt_get_entries get;
845 struct xt_table *t;
846
847 if (*len < sizeof(get))
848 return -EINVAL;
849 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
850 return -EFAULT;
851 if (*len != sizeof(struct arpt_get_entries) + get.size)
852 return -EINVAL;
853
854 get.name[sizeof(get.name) - 1] = '\0';
855
856 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
857 if (!IS_ERR(t)) {
858 const struct xt_table_info *private = t->private;
859
860 if (get.size == private->size)
861 ret = copy_entries_to_user(private->size,
862 t, uptr->entrytable);
863 else
864 ret = -EAGAIN;
865
866 module_put(t->me);
867 xt_table_unlock(t);
868 } else
869 ret = PTR_ERR(t);
870
871 return ret;
872}
873
874static int __do_replace(struct net *net, const char *name,
875 unsigned int valid_hooks,
876 struct xt_table_info *newinfo,
877 unsigned int num_counters,
878 void __user *counters_ptr)
879{
880 int ret;
881 struct xt_table *t;
882 struct xt_table_info *oldinfo;
883 struct xt_counters *counters;
884 void *loc_cpu_old_entry;
885 struct arpt_entry *iter;
886
887 ret = 0;
888 counters = xt_counters_alloc(num_counters);
889 if (!counters) {
890 ret = -ENOMEM;
891 goto out;
892 }
893
894 t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
895 if (IS_ERR(t)) {
896 ret = PTR_ERR(t);
897 goto free_newinfo_counters_untrans;
898 }
899
900 /* You lied! */
901 if (valid_hooks != t->valid_hooks) {
902 ret = -EINVAL;
903 goto put_module;
904 }
905
906 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
907 if (!oldinfo)
908 goto put_module;
909
910 /* Update module usage count based on number of rules */
911 if ((oldinfo->number > oldinfo->initial_entries) ||
912 (newinfo->number <= oldinfo->initial_entries))
913 module_put(t->me);
914 if ((oldinfo->number > oldinfo->initial_entries) &&
915 (newinfo->number <= oldinfo->initial_entries))
916 module_put(t->me);
917
918 xt_table_unlock(t);
919
920 get_old_counters(oldinfo, counters);
921
922 /* Decrease module usage counts and free resource */
923 loc_cpu_old_entry = oldinfo->entries;
924 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
925 cleanup_entry(iter);
926
927 xt_free_table_info(oldinfo);
928 if (copy_to_user(counters_ptr, counters,
929 sizeof(struct xt_counters) * num_counters) != 0) {
930 /* Silent error, can't fail, new table is already in place */
931 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
932 }
933 vfree(counters);
934 return ret;
935
936 put_module:
937 module_put(t->me);
938 xt_table_unlock(t);
939 free_newinfo_counters_untrans:
940 vfree(counters);
941 out:
942 return ret;
943}
944
945static int do_replace(struct net *net, const void __user *user,
946 unsigned int len)
947{
948 int ret;
949 struct arpt_replace tmp;
950 struct xt_table_info *newinfo;
951 void *loc_cpu_entry;
952 struct arpt_entry *iter;
953
954 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
955 return -EFAULT;
956
957 /* overflow check */
958 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
959 return -ENOMEM;
960 if (tmp.num_counters == 0)
961 return -EINVAL;
962
963 tmp.name[sizeof(tmp.name)-1] = 0;
964
965 newinfo = xt_alloc_table_info(tmp.size);
966 if (!newinfo)
967 return -ENOMEM;
968
969 loc_cpu_entry = newinfo->entries;
970 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
971 tmp.size) != 0) {
972 ret = -EFAULT;
973 goto free_newinfo;
974 }
975
976 ret = translate_table(newinfo, loc_cpu_entry, &tmp);
977 if (ret != 0)
978 goto free_newinfo;
979
980 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
981 tmp.num_counters, tmp.counters);
982 if (ret)
983 goto free_newinfo_untrans;
984 return 0;
985
986 free_newinfo_untrans:
987 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
988 cleanup_entry(iter);
989 free_newinfo:
990 xt_free_table_info(newinfo);
991 return ret;
992}
993
994static int do_add_counters(struct net *net, const void __user *user,
995 unsigned int len, int compat)
996{
997 unsigned int i;
998 struct xt_counters_info tmp;
999 struct xt_counters *paddc;
1000 struct xt_table *t;
1001 const struct xt_table_info *private;
1002 int ret = 0;
1003 struct arpt_entry *iter;
1004 unsigned int addend;
1005
1006 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1007 if (IS_ERR(paddc))
1008 return PTR_ERR(paddc);
1009
1010 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1011 if (IS_ERR(t)) {
1012 ret = PTR_ERR(t);
1013 goto free;
1014 }
1015
1016 local_bh_disable();
1017 private = t->private;
1018 if (private->number != tmp.num_counters) {
1019 ret = -EINVAL;
1020 goto unlock_up_free;
1021 }
1022
1023 i = 0;
1024
1025 addend = xt_write_recseq_begin();
1026 xt_entry_foreach(iter, private->entries, private->size) {
1027 struct xt_counters *tmp;
1028
1029 tmp = xt_get_this_cpu_counter(&iter->counters);
1030 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1031 ++i;
1032 }
1033 xt_write_recseq_end(addend);
1034 unlock_up_free:
1035 local_bh_enable();
1036 xt_table_unlock(t);
1037 module_put(t->me);
1038 free:
1039 vfree(paddc);
1040
1041 return ret;
1042}
1043
1044#ifdef CONFIG_COMPAT
1045struct compat_arpt_replace {
1046 char name[XT_TABLE_MAXNAMELEN];
1047 u32 valid_hooks;
1048 u32 num_entries;
1049 u32 size;
1050 u32 hook_entry[NF_ARP_NUMHOOKS];
1051 u32 underflow[NF_ARP_NUMHOOKS];
1052 u32 num_counters;
1053 compat_uptr_t counters;
1054 struct compat_arpt_entry entries[0];
1055};
1056
1057static inline void compat_release_entry(struct compat_arpt_entry *e)
1058{
1059 struct xt_entry_target *t;
1060
1061 t = compat_arpt_get_target(e);
1062 module_put(t->u.kernel.target->me);
1063}
1064
1065static int
1066check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1067 struct xt_table_info *newinfo,
1068 unsigned int *size,
1069 const unsigned char *base,
1070 const unsigned char *limit)
1071{
1072 struct xt_entry_target *t;
1073 struct xt_target *target;
1074 unsigned int entry_offset;
1075 int ret, off;
1076
1077 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1078 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1079 (unsigned char *)e + e->next_offset > limit)
1080 return -EINVAL;
1081
1082 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1083 sizeof(struct compat_xt_entry_target))
1084 return -EINVAL;
1085
1086 if (!arp_checkentry(&e->arp))
1087 return -EINVAL;
1088
1089 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1090 e->next_offset);
1091 if (ret)
1092 return ret;
1093
1094 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1095 entry_offset = (void *)e - (void *)base;
1096
1097 t = compat_arpt_get_target(e);
1098 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1099 t->u.user.revision);
1100 if (IS_ERR(target)) {
1101 ret = PTR_ERR(target);
1102 goto out;
1103 }
1104 t->u.kernel.target = target;
1105
1106 off += xt_compat_target_offset(target);
1107 *size += off;
1108 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1109 if (ret)
1110 goto release_target;
1111
1112 return 0;
1113
1114release_target:
1115 module_put(t->u.kernel.target->me);
1116out:
1117 return ret;
1118}
1119
1120static void
1121compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1122 unsigned int *size,
1123 struct xt_table_info *newinfo, unsigned char *base)
1124{
1125 struct xt_entry_target *t;
1126 struct arpt_entry *de;
1127 unsigned int origsize;
1128 int h;
1129
1130 origsize = *size;
1131 de = *dstptr;
1132 memcpy(de, e, sizeof(struct arpt_entry));
1133 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1134
1135 *dstptr += sizeof(struct arpt_entry);
1136 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1137
1138 de->target_offset = e->target_offset - (origsize - *size);
1139 t = compat_arpt_get_target(e);
1140 xt_compat_target_from_user(t, dstptr, size);
1141
1142 de->next_offset = e->next_offset - (origsize - *size);
1143 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1144 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1145 newinfo->hook_entry[h] -= origsize - *size;
1146 if ((unsigned char *)de - base < newinfo->underflow[h])
1147 newinfo->underflow[h] -= origsize - *size;
1148 }
1149}
1150
1151static int translate_compat_table(struct xt_table_info **pinfo,
1152 void **pentry0,
1153 const struct compat_arpt_replace *compatr)
1154{
1155 unsigned int i, j;
1156 struct xt_table_info *newinfo, *info;
1157 void *pos, *entry0, *entry1;
1158 struct compat_arpt_entry *iter0;
1159 struct arpt_replace repl;
1160 unsigned int size;
1161 int ret;
1162
1163 info = *pinfo;
1164 entry0 = *pentry0;
1165 size = compatr->size;
1166 info->number = compatr->num_entries;
1167
1168 j = 0;
1169 xt_compat_lock(NFPROTO_ARP);
1170 ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1171 if (ret)
1172 goto out_unlock;
1173 /* Walk through entries, checking offsets. */
1174 xt_entry_foreach(iter0, entry0, compatr->size) {
1175 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1176 entry0,
1177 entry0 + compatr->size);
1178 if (ret != 0)
1179 goto out_unlock;
1180 ++j;
1181 }
1182
1183 ret = -EINVAL;
1184 if (j != compatr->num_entries)
1185 goto out_unlock;
1186
1187 ret = -ENOMEM;
1188 newinfo = xt_alloc_table_info(size);
1189 if (!newinfo)
1190 goto out_unlock;
1191
1192 newinfo->number = compatr->num_entries;
1193 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1194 newinfo->hook_entry[i] = compatr->hook_entry[i];
1195 newinfo->underflow[i] = compatr->underflow[i];
1196 }
1197 entry1 = newinfo->entries;
1198 pos = entry1;
1199 size = compatr->size;
1200 xt_entry_foreach(iter0, entry0, compatr->size)
1201 compat_copy_entry_from_user(iter0, &pos, &size,
1202 newinfo, entry1);
1203
1204 /* all module references in entry0 are now gone */
1205
1206 xt_compat_flush_offsets(NFPROTO_ARP);
1207 xt_compat_unlock(NFPROTO_ARP);
1208
1209 memcpy(&repl, compatr, sizeof(*compatr));
1210
1211 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1212 repl.hook_entry[i] = newinfo->hook_entry[i];
1213 repl.underflow[i] = newinfo->underflow[i];
1214 }
1215
1216 repl.num_counters = 0;
1217 repl.counters = NULL;
1218 repl.size = newinfo->size;
1219 ret = translate_table(newinfo, entry1, &repl);
1220 if (ret)
1221 goto free_newinfo;
1222
1223 *pinfo = newinfo;
1224 *pentry0 = entry1;
1225 xt_free_table_info(info);
1226 return 0;
1227
1228free_newinfo:
1229 xt_free_table_info(newinfo);
1230 return ret;
1231out_unlock:
1232 xt_compat_flush_offsets(NFPROTO_ARP);
1233 xt_compat_unlock(NFPROTO_ARP);
1234 xt_entry_foreach(iter0, entry0, compatr->size) {
1235 if (j-- == 0)
1236 break;
1237 compat_release_entry(iter0);
1238 }
1239 return ret;
1240}
1241
1242static int compat_do_replace(struct net *net, void __user *user,
1243 unsigned int len)
1244{
1245 int ret;
1246 struct compat_arpt_replace tmp;
1247 struct xt_table_info *newinfo;
1248 void *loc_cpu_entry;
1249 struct arpt_entry *iter;
1250
1251 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1252 return -EFAULT;
1253
1254 /* overflow check */
1255 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1256 return -ENOMEM;
1257 if (tmp.num_counters == 0)
1258 return -EINVAL;
1259
1260 tmp.name[sizeof(tmp.name)-1] = 0;
1261
1262 newinfo = xt_alloc_table_info(tmp.size);
1263 if (!newinfo)
1264 return -ENOMEM;
1265
1266 loc_cpu_entry = newinfo->entries;
1267 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1268 ret = -EFAULT;
1269 goto free_newinfo;
1270 }
1271
1272 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1273 if (ret != 0)
1274 goto free_newinfo;
1275
1276 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1277 tmp.num_counters, compat_ptr(tmp.counters));
1278 if (ret)
1279 goto free_newinfo_untrans;
1280 return 0;
1281
1282 free_newinfo_untrans:
1283 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1284 cleanup_entry(iter);
1285 free_newinfo:
1286 xt_free_table_info(newinfo);
1287 return ret;
1288}
1289
1290static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1291 unsigned int len)
1292{
1293 int ret;
1294
1295 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1296 return -EPERM;
1297
1298 switch (cmd) {
1299 case ARPT_SO_SET_REPLACE:
1300 ret = compat_do_replace(sock_net(sk), user, len);
1301 break;
1302
1303 case ARPT_SO_SET_ADD_COUNTERS:
1304 ret = do_add_counters(sock_net(sk), user, len, 1);
1305 break;
1306
1307 default:
1308 ret = -EINVAL;
1309 }
1310
1311 return ret;
1312}
1313
1314static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1315 compat_uint_t *size,
1316 struct xt_counters *counters,
1317 unsigned int i)
1318{
1319 struct xt_entry_target *t;
1320 struct compat_arpt_entry __user *ce;
1321 u_int16_t target_offset, next_offset;
1322 compat_uint_t origsize;
1323 int ret;
1324
1325 origsize = *size;
1326 ce = *dstptr;
1327 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1328 copy_to_user(&ce->counters, &counters[i],
1329 sizeof(counters[i])) != 0)
1330 return -EFAULT;
1331
1332 *dstptr += sizeof(struct compat_arpt_entry);
1333 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1334
1335 target_offset = e->target_offset - (origsize - *size);
1336
1337 t = arpt_get_target(e);
1338 ret = xt_compat_target_to_user(t, dstptr, size);
1339 if (ret)
1340 return ret;
1341 next_offset = e->next_offset - (origsize - *size);
1342 if (put_user(target_offset, &ce->target_offset) != 0 ||
1343 put_user(next_offset, &ce->next_offset) != 0)
1344 return -EFAULT;
1345 return 0;
1346}
1347
1348static int compat_copy_entries_to_user(unsigned int total_size,
1349 struct xt_table *table,
1350 void __user *userptr)
1351{
1352 struct xt_counters *counters;
1353 const struct xt_table_info *private = table->private;
1354 void __user *pos;
1355 unsigned int size;
1356 int ret = 0;
1357 unsigned int i = 0;
1358 struct arpt_entry *iter;
1359
1360 counters = alloc_counters(table);
1361 if (IS_ERR(counters))
1362 return PTR_ERR(counters);
1363
1364 pos = userptr;
1365 size = total_size;
1366 xt_entry_foreach(iter, private->entries, total_size) {
1367 ret = compat_copy_entry_to_user(iter, &pos,
1368 &size, counters, i++);
1369 if (ret != 0)
1370 break;
1371 }
1372 vfree(counters);
1373 return ret;
1374}
1375
1376struct compat_arpt_get_entries {
1377 char name[XT_TABLE_MAXNAMELEN];
1378 compat_uint_t size;
1379 struct compat_arpt_entry entrytable[0];
1380};
1381
1382static int compat_get_entries(struct net *net,
1383 struct compat_arpt_get_entries __user *uptr,
1384 int *len)
1385{
1386 int ret;
1387 struct compat_arpt_get_entries get;
1388 struct xt_table *t;
1389
1390 if (*len < sizeof(get))
1391 return -EINVAL;
1392 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1393 return -EFAULT;
1394 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1395 return -EINVAL;
1396
1397 get.name[sizeof(get.name) - 1] = '\0';
1398
1399 xt_compat_lock(NFPROTO_ARP);
1400 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1401 if (!IS_ERR(t)) {
1402 const struct xt_table_info *private = t->private;
1403 struct xt_table_info info;
1404
1405 ret = compat_table_info(private, &info);
1406 if (!ret && get.size == info.size) {
1407 ret = compat_copy_entries_to_user(private->size,
1408 t, uptr->entrytable);
1409 } else if (!ret)
1410 ret = -EAGAIN;
1411
1412 xt_compat_flush_offsets(NFPROTO_ARP);
1413 module_put(t->me);
1414 xt_table_unlock(t);
1415 } else
1416 ret = PTR_ERR(t);
1417
1418 xt_compat_unlock(NFPROTO_ARP);
1419 return ret;
1420}
1421
1422static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1423
1424static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1425 int *len)
1426{
1427 int ret;
1428
1429 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1430 return -EPERM;
1431
1432 switch (cmd) {
1433 case ARPT_SO_GET_INFO:
1434 ret = get_info(sock_net(sk), user, len, 1);
1435 break;
1436 case ARPT_SO_GET_ENTRIES:
1437 ret = compat_get_entries(sock_net(sk), user, len);
1438 break;
1439 default:
1440 ret = do_arpt_get_ctl(sk, cmd, user, len);
1441 }
1442 return ret;
1443}
1444#endif
1445
1446static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1447{
1448 int ret;
1449
1450 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1451 return -EPERM;
1452
1453 switch (cmd) {
1454 case ARPT_SO_SET_REPLACE:
1455 ret = do_replace(sock_net(sk), user, len);
1456 break;
1457
1458 case ARPT_SO_SET_ADD_COUNTERS:
1459 ret = do_add_counters(sock_net(sk), user, len, 0);
1460 break;
1461
1462 default:
1463 ret = -EINVAL;
1464 }
1465
1466 return ret;
1467}
1468
1469static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1470{
1471 int ret;
1472
1473 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1474 return -EPERM;
1475
1476 switch (cmd) {
1477 case ARPT_SO_GET_INFO:
1478 ret = get_info(sock_net(sk), user, len, 0);
1479 break;
1480
1481 case ARPT_SO_GET_ENTRIES:
1482 ret = get_entries(sock_net(sk), user, len);
1483 break;
1484
1485 case ARPT_SO_GET_REVISION_TARGET: {
1486 struct xt_get_revision rev;
1487
1488 if (*len != sizeof(rev)) {
1489 ret = -EINVAL;
1490 break;
1491 }
1492 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1493 ret = -EFAULT;
1494 break;
1495 }
1496 rev.name[sizeof(rev.name)-1] = 0;
1497
1498 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1499 rev.revision, 1, &ret),
1500 "arpt_%s", rev.name);
1501 break;
1502 }
1503
1504 default:
1505 ret = -EINVAL;
1506 }
1507
1508 return ret;
1509}
1510
1511static void __arpt_unregister_table(struct xt_table *table)
1512{
1513 struct xt_table_info *private;
1514 void *loc_cpu_entry;
1515 struct module *table_owner = table->me;
1516 struct arpt_entry *iter;
1517
1518 private = xt_unregister_table(table);
1519
1520 /* Decrease module usage counts and free resources */
1521 loc_cpu_entry = private->entries;
1522 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1523 cleanup_entry(iter);
1524 if (private->number > private->initial_entries)
1525 module_put(table_owner);
1526 xt_free_table_info(private);
1527}
1528
1529int arpt_register_table(struct net *net,
1530 const struct xt_table *table,
1531 const struct arpt_replace *repl,
1532 const struct nf_hook_ops *ops,
1533 struct xt_table **res)
1534{
1535 int ret;
1536 struct xt_table_info *newinfo;
1537 struct xt_table_info bootstrap = {0};
1538 void *loc_cpu_entry;
1539 struct xt_table *new_table;
1540
1541 newinfo = xt_alloc_table_info(repl->size);
1542 if (!newinfo)
1543 return -ENOMEM;
1544
1545 loc_cpu_entry = newinfo->entries;
1546 memcpy(loc_cpu_entry, repl->entries, repl->size);
1547
1548 ret = translate_table(newinfo, loc_cpu_entry, repl);
1549 if (ret != 0)
1550 goto out_free;
1551
1552 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1553 if (IS_ERR(new_table)) {
1554 ret = PTR_ERR(new_table);
1555 goto out_free;
1556 }
1557
1558 /* set res now, will see skbs right after nf_register_net_hooks */
1559 WRITE_ONCE(*res, new_table);
1560
1561 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1562 if (ret != 0) {
1563 __arpt_unregister_table(new_table);
1564 *res = NULL;
1565 }
1566
1567 return ret;
1568
1569out_free:
1570 xt_free_table_info(newinfo);
1571 return ret;
1572}
1573
1574void arpt_unregister_table(struct net *net, struct xt_table *table,
1575 const struct nf_hook_ops *ops)
1576{
1577 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1578 __arpt_unregister_table(table);
1579}
1580
1581/* The built-in targets: standard (NULL) and error. */
1582static 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_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
1601static 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#ifdef CONFIG_COMPAT
1607 .compat_set = compat_do_arpt_set_ctl,
1608#endif
1609 .get_optmin = ARPT_BASE_CTL,
1610 .get_optmax = ARPT_SO_GET_MAX+1,
1611 .get = do_arpt_get_ctl,
1612#ifdef CONFIG_COMPAT
1613 .compat_get = compat_do_arpt_get_ctl,
1614#endif
1615 .owner = THIS_MODULE,
1616};
1617
1618static int __net_init arp_tables_net_init(struct net *net)
1619{
1620 return xt_proto_init(net, NFPROTO_ARP);
1621}
1622
1623static void __net_exit arp_tables_net_exit(struct net *net)
1624{
1625 xt_proto_fini(net, NFPROTO_ARP);
1626}
1627
1628static struct pernet_operations arp_tables_net_ops = {
1629 .init = arp_tables_net_init,
1630 .exit = arp_tables_net_exit,
1631};
1632
1633static int __init arp_tables_init(void)
1634{
1635 int ret;
1636
1637 ret = register_pernet_subsys(&arp_tables_net_ops);
1638 if (ret < 0)
1639 goto err1;
1640
1641 /* No one else will be downing sem now, so we won't sleep */
1642 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1643 if (ret < 0)
1644 goto err2;
1645
1646 /* Register setsockopt */
1647 ret = nf_register_sockopt(&arpt_sockopts);
1648 if (ret < 0)
1649 goto err4;
1650
1651 return 0;
1652
1653err4:
1654 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1655err2:
1656 unregister_pernet_subsys(&arp_tables_net_ops);
1657err1:
1658 return ret;
1659}
1660
1661static void __exit arp_tables_fini(void)
1662{
1663 nf_unregister_sockopt(&arpt_sockopts);
1664 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1665 unregister_pernet_subsys(&arp_tables_net_ops);
1666}
1667
1668EXPORT_SYMBOL(arpt_register_table);
1669EXPORT_SYMBOL(arpt_unregister_table);
1670EXPORT_SYMBOL(arpt_do_table);
1671
1672module_init(arp_tables_init);
1673module_exit(arp_tables_fini);
1674