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[mirror_ubuntu-artful-kernel.git] / net / ipv4 / netfilter / arp_tables.c
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 <asm/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
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
35 MODULE_DESCRIPTION("arptables core");
36
37 void *arpt_alloc_initial_table(const struct xt_table *info)
38 {
39 return xt_alloc_initial_table(arpt, ARPT);
40 }
41 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
42
43 static 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 */
63 static 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. */
81 static 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
144 static 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
154 static unsigned int
155 arpt_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
163 static inline const struct xt_entry_target *
164 arpt_get_target_c(const struct arpt_entry *e)
165 {
166 return arpt_get_target((struct arpt_entry *)e);
167 }
168
169 static inline struct arpt_entry *
170 get_entry(const void *base, unsigned int offset)
171 {
172 return (struct arpt_entry *)(base + offset);
173 }
174
175 static inline
176 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
177 {
178 return (void *)entry + entry->next_offset;
179 }
180
181 unsigned 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 = table->private;
206 cpu = smp_processor_id();
207 /*
208 * Ensure we load private-> members after we've fetched the base
209 * pointer.
210 */
211 smp_read_barrier_depends();
212 table_base = private->entries;
213 jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
214
215 /* No TEE support for arptables, so no need to switch to alternate
216 * stack. All targets that reenter must return absolute verdicts.
217 */
218 e = get_entry(table_base, private->hook_entry[hook]);
219
220 acpar.state = state;
221 acpar.hotdrop = false;
222
223 arp = arp_hdr(skb);
224 do {
225 const struct xt_entry_target *t;
226 struct xt_counters *counter;
227
228 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
229 e = arpt_next_entry(e);
230 continue;
231 }
232
233 counter = xt_get_this_cpu_counter(&e->counters);
234 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
235
236 t = arpt_get_target_c(e);
237
238 /* Standard target? */
239 if (!t->u.kernel.target->target) {
240 int v;
241
242 v = ((struct xt_standard_target *)t)->verdict;
243 if (v < 0) {
244 /* Pop from stack? */
245 if (v != XT_RETURN) {
246 verdict = (unsigned int)(-v) - 1;
247 break;
248 }
249 if (stackidx == 0) {
250 e = get_entry(table_base,
251 private->underflow[hook]);
252 } else {
253 e = jumpstack[--stackidx];
254 e = arpt_next_entry(e);
255 }
256 continue;
257 }
258 if (table_base + v
259 != arpt_next_entry(e)) {
260 jumpstack[stackidx++] = e;
261 }
262
263 e = get_entry(table_base, v);
264 continue;
265 }
266
267 acpar.target = t->u.kernel.target;
268 acpar.targinfo = t->data;
269 verdict = t->u.kernel.target->target(skb, &acpar);
270
271 /* Target might have changed stuff. */
272 arp = arp_hdr(skb);
273
274 if (verdict == XT_CONTINUE)
275 e = arpt_next_entry(e);
276 else
277 /* Verdict */
278 break;
279 } while (!acpar.hotdrop);
280 xt_write_recseq_end(addend);
281 local_bh_enable();
282
283 if (acpar.hotdrop)
284 return NF_DROP;
285 else
286 return verdict;
287 }
288
289 /* All zeroes == unconditional rule. */
290 static inline bool unconditional(const struct arpt_entry *e)
291 {
292 static const struct arpt_arp uncond;
293
294 return e->target_offset == sizeof(struct arpt_entry) &&
295 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
296 }
297
298 /* Figures out from what hook each rule can be called: returns 0 if
299 * there are loops. Puts hook bitmask in comefrom.
300 */
301 static int mark_source_chains(const struct xt_table_info *newinfo,
302 unsigned int valid_hooks, void *entry0,
303 unsigned int *offsets)
304 {
305 unsigned int hook;
306
307 /* No recursion; use packet counter to save back ptrs (reset
308 * to 0 as we leave), and comefrom to save source hook bitmask.
309 */
310 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
311 unsigned int pos = newinfo->hook_entry[hook];
312 struct arpt_entry *e
313 = (struct arpt_entry *)(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 if ((strcmp(t->target.u.user.name,
340 XT_STANDARD_TARGET) == 0) &&
341 t->verdict < -NF_MAX_VERDICT - 1)
342 return 0;
343
344 /* Return: backtrack through the last
345 * big jump.
346 */
347 do {
348 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
349 oldpos = pos;
350 pos = e->counters.pcnt;
351 e->counters.pcnt = 0;
352
353 /* We're at the start. */
354 if (pos == oldpos)
355 goto next;
356
357 e = (struct arpt_entry *)
358 (entry0 + pos);
359 } while (oldpos == pos + e->next_offset);
360
361 /* Move along one */
362 size = e->next_offset;
363 e = (struct arpt_entry *)
364 (entry0 + pos + size);
365 if (pos + size >= newinfo->size)
366 return 0;
367 e->counters.pcnt = pos;
368 pos += size;
369 } else {
370 int newpos = t->verdict;
371
372 if (strcmp(t->target.u.user.name,
373 XT_STANDARD_TARGET) == 0 &&
374 newpos >= 0) {
375 /* This a jump; chase it. */
376 if (!xt_find_jump_offset(offsets, newpos,
377 newinfo->number))
378 return 0;
379 e = (struct arpt_entry *)
380 (entry0 + newpos);
381 } else {
382 /* ... this is a fallthru */
383 newpos = pos + e->next_offset;
384 if (newpos >= newinfo->size)
385 return 0;
386 }
387 e = (struct arpt_entry *)
388 (entry0 + newpos);
389 e->counters.pcnt = pos;
390 pos = newpos;
391 }
392 }
393 next: ;
394 }
395 return 1;
396 }
397
398 static inline int check_target(struct arpt_entry *e, const char *name)
399 {
400 struct xt_entry_target *t = arpt_get_target(e);
401 struct xt_tgchk_param par = {
402 .table = name,
403 .entryinfo = e,
404 .target = t->u.kernel.target,
405 .targinfo = t->data,
406 .hook_mask = e->comefrom,
407 .family = NFPROTO_ARP,
408 };
409
410 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
411 }
412
413 static inline int
414 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
415 {
416 struct xt_entry_target *t;
417 struct xt_target *target;
418 unsigned long pcnt;
419 int ret;
420
421 pcnt = xt_percpu_counter_alloc();
422 if (IS_ERR_VALUE(pcnt))
423 return -ENOMEM;
424 e->counters.pcnt = pcnt;
425
426 t = arpt_get_target(e);
427 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
428 t->u.user.revision);
429 if (IS_ERR(target)) {
430 ret = PTR_ERR(target);
431 goto out;
432 }
433 t->u.kernel.target = target;
434
435 ret = check_target(e, name);
436 if (ret)
437 goto err;
438 return 0;
439 err:
440 module_put(t->u.kernel.target->me);
441 out:
442 xt_percpu_counter_free(&e->counters);
443
444 return ret;
445 }
446
447 static bool check_underflow(const struct arpt_entry *e)
448 {
449 const struct xt_entry_target *t;
450 unsigned int verdict;
451
452 if (!unconditional(e))
453 return false;
454 t = arpt_get_target_c(e);
455 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
456 return false;
457 verdict = ((struct xt_standard_target *)t)->verdict;
458 verdict = -verdict - 1;
459 return verdict == NF_DROP || verdict == NF_ACCEPT;
460 }
461
462 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
463 struct xt_table_info *newinfo,
464 const unsigned char *base,
465 const unsigned char *limit,
466 const unsigned int *hook_entries,
467 const unsigned int *underflows,
468 unsigned int valid_hooks)
469 {
470 unsigned int h;
471 int err;
472
473 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
474 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
475 (unsigned char *)e + e->next_offset > limit)
476 return -EINVAL;
477
478 if (e->next_offset
479 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
480 return -EINVAL;
481
482 if (!arp_checkentry(&e->arp))
483 return -EINVAL;
484
485 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
486 e->next_offset);
487 if (err)
488 return err;
489
490 /* Check hooks & underflows */
491 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
492 if (!(valid_hooks & (1 << h)))
493 continue;
494 if ((unsigned char *)e - base == hook_entries[h])
495 newinfo->hook_entry[h] = hook_entries[h];
496 if ((unsigned char *)e - base == underflows[h]) {
497 if (!check_underflow(e))
498 return -EINVAL;
499
500 newinfo->underflow[h] = underflows[h];
501 }
502 }
503
504 /* Clear counters and comefrom */
505 e->counters = ((struct xt_counters) { 0, 0 });
506 e->comefrom = 0;
507 return 0;
508 }
509
510 static inline void cleanup_entry(struct arpt_entry *e)
511 {
512 struct xt_tgdtor_param par;
513 struct xt_entry_target *t;
514
515 t = arpt_get_target(e);
516 par.target = t->u.kernel.target;
517 par.targinfo = t->data;
518 par.family = NFPROTO_ARP;
519 if (par.target->destroy != NULL)
520 par.target->destroy(&par);
521 module_put(par.target->me);
522 xt_percpu_counter_free(&e->counters);
523 }
524
525 /* Checks and translates the user-supplied table segment (held in
526 * newinfo).
527 */
528 static int translate_table(struct xt_table_info *newinfo, void *entry0,
529 const struct arpt_replace *repl)
530 {
531 struct arpt_entry *iter;
532 unsigned int *offsets;
533 unsigned int i;
534 int ret = 0;
535
536 newinfo->size = repl->size;
537 newinfo->number = repl->num_entries;
538
539 /* Init all hooks to impossible value. */
540 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
541 newinfo->hook_entry[i] = 0xFFFFFFFF;
542 newinfo->underflow[i] = 0xFFFFFFFF;
543 }
544
545 offsets = xt_alloc_entry_offsets(newinfo->number);
546 if (!offsets)
547 return -ENOMEM;
548 i = 0;
549
550 /* Walk through entries, checking offsets. */
551 xt_entry_foreach(iter, entry0, newinfo->size) {
552 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
553 entry0 + repl->size,
554 repl->hook_entry,
555 repl->underflow,
556 repl->valid_hooks);
557 if (ret != 0)
558 goto out_free;
559 if (i < repl->num_entries)
560 offsets[i] = (void *)iter - entry0;
561 ++i;
562 if (strcmp(arpt_get_target(iter)->u.user.name,
563 XT_ERROR_TARGET) == 0)
564 ++newinfo->stacksize;
565 }
566 if (ret != 0)
567 goto out_free;
568
569 ret = -EINVAL;
570 if (i != repl->num_entries)
571 goto out_free;
572
573 /* Check hooks all assigned */
574 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
575 /* Only hooks which are valid */
576 if (!(repl->valid_hooks & (1 << i)))
577 continue;
578 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
579 goto out_free;
580 if (newinfo->underflow[i] == 0xFFFFFFFF)
581 goto out_free;
582 }
583
584 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
585 ret = -ELOOP;
586 goto out_free;
587 }
588 kvfree(offsets);
589
590 /* Finally, each sanity check must pass */
591 i = 0;
592 xt_entry_foreach(iter, entry0, newinfo->size) {
593 ret = find_check_entry(iter, repl->name, repl->size);
594 if (ret != 0)
595 break;
596 ++i;
597 }
598
599 if (ret != 0) {
600 xt_entry_foreach(iter, entry0, newinfo->size) {
601 if (i-- == 0)
602 break;
603 cleanup_entry(iter);
604 }
605 return ret;
606 }
607
608 return ret;
609 out_free:
610 kvfree(offsets);
611 return ret;
612 }
613
614 static void get_counters(const struct xt_table_info *t,
615 struct xt_counters counters[])
616 {
617 struct arpt_entry *iter;
618 unsigned int cpu;
619 unsigned int i;
620
621 for_each_possible_cpu(cpu) {
622 seqcount_t *s = &per_cpu(xt_recseq, cpu);
623
624 i = 0;
625 xt_entry_foreach(iter, t->entries, t->size) {
626 struct xt_counters *tmp;
627 u64 bcnt, pcnt;
628 unsigned int start;
629
630 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
631 do {
632 start = read_seqcount_begin(s);
633 bcnt = tmp->bcnt;
634 pcnt = tmp->pcnt;
635 } while (read_seqcount_retry(s, start));
636
637 ADD_COUNTER(counters[i], bcnt, pcnt);
638 ++i;
639 }
640 }
641 }
642
643 static struct xt_counters *alloc_counters(const struct xt_table *table)
644 {
645 unsigned int countersize;
646 struct xt_counters *counters;
647 const struct xt_table_info *private = table->private;
648
649 /* We need atomic snapshot of counters: rest doesn't change
650 * (other than comefrom, which userspace doesn't care
651 * about).
652 */
653 countersize = sizeof(struct xt_counters) * private->number;
654 counters = vzalloc(countersize);
655
656 if (counters == NULL)
657 return ERR_PTR(-ENOMEM);
658
659 get_counters(private, counters);
660
661 return counters;
662 }
663
664 static int copy_entries_to_user(unsigned int total_size,
665 const struct xt_table *table,
666 void __user *userptr)
667 {
668 unsigned int off, num;
669 const struct arpt_entry *e;
670 struct xt_counters *counters;
671 struct xt_table_info *private = table->private;
672 int ret = 0;
673 void *loc_cpu_entry;
674
675 counters = alloc_counters(table);
676 if (IS_ERR(counters))
677 return PTR_ERR(counters);
678
679 loc_cpu_entry = private->entries;
680 /* ... then copy entire thing ... */
681 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
682 ret = -EFAULT;
683 goto free_counters;
684 }
685
686 /* FIXME: use iterator macros --RR */
687 /* ... then go back and fix counters and names */
688 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
689 const struct xt_entry_target *t;
690
691 e = (struct arpt_entry *)(loc_cpu_entry + off);
692 if (copy_to_user(userptr + off
693 + offsetof(struct arpt_entry, counters),
694 &counters[num],
695 sizeof(counters[num])) != 0) {
696 ret = -EFAULT;
697 goto free_counters;
698 }
699
700 t = arpt_get_target_c(e);
701 if (copy_to_user(userptr + off + e->target_offset
702 + offsetof(struct xt_entry_target,
703 u.user.name),
704 t->u.kernel.target->name,
705 strlen(t->u.kernel.target->name)+1) != 0) {
706 ret = -EFAULT;
707 goto free_counters;
708 }
709 }
710
711 free_counters:
712 vfree(counters);
713 return ret;
714 }
715
716 #ifdef CONFIG_COMPAT
717 static void compat_standard_from_user(void *dst, const void *src)
718 {
719 int v = *(compat_int_t *)src;
720
721 if (v > 0)
722 v += xt_compat_calc_jump(NFPROTO_ARP, v);
723 memcpy(dst, &v, sizeof(v));
724 }
725
726 static int compat_standard_to_user(void __user *dst, const void *src)
727 {
728 compat_int_t cv = *(int *)src;
729
730 if (cv > 0)
731 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
732 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
733 }
734
735 static int compat_calc_entry(const struct arpt_entry *e,
736 const struct xt_table_info *info,
737 const void *base, struct xt_table_info *newinfo)
738 {
739 const struct xt_entry_target *t;
740 unsigned int entry_offset;
741 int off, i, ret;
742
743 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
744 entry_offset = (void *)e - base;
745
746 t = arpt_get_target_c(e);
747 off += xt_compat_target_offset(t->u.kernel.target);
748 newinfo->size -= off;
749 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
750 if (ret)
751 return ret;
752
753 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
754 if (info->hook_entry[i] &&
755 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
756 newinfo->hook_entry[i] -= off;
757 if (info->underflow[i] &&
758 (e < (struct arpt_entry *)(base + info->underflow[i])))
759 newinfo->underflow[i] -= off;
760 }
761 return 0;
762 }
763
764 static int compat_table_info(const struct xt_table_info *info,
765 struct xt_table_info *newinfo)
766 {
767 struct arpt_entry *iter;
768 const void *loc_cpu_entry;
769 int ret;
770
771 if (!newinfo || !info)
772 return -EINVAL;
773
774 /* we dont care about newinfo->entries */
775 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
776 newinfo->initial_entries = 0;
777 loc_cpu_entry = info->entries;
778 xt_compat_init_offsets(NFPROTO_ARP, info->number);
779 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
780 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
781 if (ret != 0)
782 return ret;
783 }
784 return 0;
785 }
786 #endif
787
788 static int get_info(struct net *net, void __user *user,
789 const int *len, int compat)
790 {
791 char name[XT_TABLE_MAXNAMELEN];
792 struct xt_table *t;
793 int ret;
794
795 if (*len != sizeof(struct arpt_getinfo))
796 return -EINVAL;
797
798 if (copy_from_user(name, user, sizeof(name)) != 0)
799 return -EFAULT;
800
801 name[XT_TABLE_MAXNAMELEN-1] = '\0';
802 #ifdef CONFIG_COMPAT
803 if (compat)
804 xt_compat_lock(NFPROTO_ARP);
805 #endif
806 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
807 "arptable_%s", name);
808 if (t) {
809 struct arpt_getinfo info;
810 const struct xt_table_info *private = t->private;
811 #ifdef CONFIG_COMPAT
812 struct xt_table_info tmp;
813
814 if (compat) {
815 ret = compat_table_info(private, &tmp);
816 xt_compat_flush_offsets(NFPROTO_ARP);
817 private = &tmp;
818 }
819 #endif
820 memset(&info, 0, sizeof(info));
821 info.valid_hooks = t->valid_hooks;
822 memcpy(info.hook_entry, private->hook_entry,
823 sizeof(info.hook_entry));
824 memcpy(info.underflow, private->underflow,
825 sizeof(info.underflow));
826 info.num_entries = private->number;
827 info.size = private->size;
828 strcpy(info.name, name);
829
830 if (copy_to_user(user, &info, *len) != 0)
831 ret = -EFAULT;
832 else
833 ret = 0;
834 xt_table_unlock(t);
835 module_put(t->me);
836 } else
837 ret = -ENOENT;
838 #ifdef CONFIG_COMPAT
839 if (compat)
840 xt_compat_unlock(NFPROTO_ARP);
841 #endif
842 return ret;
843 }
844
845 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
846 const int *len)
847 {
848 int ret;
849 struct arpt_get_entries get;
850 struct xt_table *t;
851
852 if (*len < sizeof(get))
853 return -EINVAL;
854 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
855 return -EFAULT;
856 if (*len != sizeof(struct arpt_get_entries) + get.size)
857 return -EINVAL;
858
859 get.name[sizeof(get.name) - 1] = '\0';
860
861 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
862 if (t) {
863 const struct xt_table_info *private = t->private;
864
865 if (get.size == private->size)
866 ret = copy_entries_to_user(private->size,
867 t, uptr->entrytable);
868 else
869 ret = -EAGAIN;
870
871 module_put(t->me);
872 xt_table_unlock(t);
873 } else
874 ret = -ENOENT;
875
876 return ret;
877 }
878
879 static int __do_replace(struct net *net, const char *name,
880 unsigned int valid_hooks,
881 struct xt_table_info *newinfo,
882 unsigned int num_counters,
883 void __user *counters_ptr)
884 {
885 int ret;
886 struct xt_table *t;
887 struct xt_table_info *oldinfo;
888 struct xt_counters *counters;
889 void *loc_cpu_old_entry;
890 struct arpt_entry *iter;
891
892 ret = 0;
893 counters = vzalloc(num_counters * sizeof(struct xt_counters));
894 if (!counters) {
895 ret = -ENOMEM;
896 goto out;
897 }
898
899 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
900 "arptable_%s", name);
901 if (!t) {
902 ret = -ENOENT;
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(t, num_counters, newinfo, &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(t->me);
920 if ((oldinfo->number > oldinfo->initial_entries) &&
921 (newinfo->number <= oldinfo->initial_entries))
922 module_put(t->me);
923
924 /* Get the old counters, and synchronize with replace */
925 get_counters(oldinfo, counters);
926
927 /* Decrease module usage counts and free resource */
928 loc_cpu_old_entry = oldinfo->entries;
929 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
930 cleanup_entry(iter);
931
932 xt_free_table_info(oldinfo);
933 if (copy_to_user(counters_ptr, counters,
934 sizeof(struct xt_counters) * num_counters) != 0) {
935 /* Silent error, can't fail, new table is already in place */
936 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
937 }
938 vfree(counters);
939 xt_table_unlock(t);
940 return ret;
941
942 put_module:
943 module_put(t->me);
944 xt_table_unlock(t);
945 free_newinfo_counters_untrans:
946 vfree(counters);
947 out:
948 return ret;
949 }
950
951 static int do_replace(struct net *net, const void __user *user,
952 unsigned int len)
953 {
954 int ret;
955 struct arpt_replace tmp;
956 struct xt_table_info *newinfo;
957 void *loc_cpu_entry;
958 struct arpt_entry *iter;
959
960 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
961 return -EFAULT;
962
963 /* overflow check */
964 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
965 return -ENOMEM;
966 if (tmp.num_counters == 0)
967 return -EINVAL;
968
969 tmp.name[sizeof(tmp.name)-1] = 0;
970
971 newinfo = xt_alloc_table_info(tmp.size);
972 if (!newinfo)
973 return -ENOMEM;
974
975 loc_cpu_entry = newinfo->entries;
976 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
977 tmp.size) != 0) {
978 ret = -EFAULT;
979 goto free_newinfo;
980 }
981
982 ret = translate_table(newinfo, loc_cpu_entry, &tmp);
983 if (ret != 0)
984 goto free_newinfo;
985
986 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
987 tmp.num_counters, tmp.counters);
988 if (ret)
989 goto free_newinfo_untrans;
990 return 0;
991
992 free_newinfo_untrans:
993 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
994 cleanup_entry(iter);
995 free_newinfo:
996 xt_free_table_info(newinfo);
997 return ret;
998 }
999
1000 static int do_add_counters(struct net *net, const void __user *user,
1001 unsigned int len, int compat)
1002 {
1003 unsigned int i;
1004 struct xt_counters_info tmp;
1005 struct xt_counters *paddc;
1006 struct xt_table *t;
1007 const struct xt_table_info *private;
1008 int ret = 0;
1009 struct arpt_entry *iter;
1010 unsigned int addend;
1011
1012 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1013 if (IS_ERR(paddc))
1014 return PTR_ERR(paddc);
1015
1016 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1017 if (!t) {
1018 ret = -ENOENT;
1019 goto free;
1020 }
1021
1022 local_bh_disable();
1023 private = t->private;
1024 if (private->number != tmp.num_counters) {
1025 ret = -EINVAL;
1026 goto unlock_up_free;
1027 }
1028
1029 i = 0;
1030
1031 addend = xt_write_recseq_begin();
1032 xt_entry_foreach(iter, private->entries, private->size) {
1033 struct xt_counters *tmp;
1034
1035 tmp = xt_get_this_cpu_counter(&iter->counters);
1036 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1037 ++i;
1038 }
1039 xt_write_recseq_end(addend);
1040 unlock_up_free:
1041 local_bh_enable();
1042 xt_table_unlock(t);
1043 module_put(t->me);
1044 free:
1045 vfree(paddc);
1046
1047 return ret;
1048 }
1049
1050 #ifdef CONFIG_COMPAT
1051 struct compat_arpt_replace {
1052 char name[XT_TABLE_MAXNAMELEN];
1053 u32 valid_hooks;
1054 u32 num_entries;
1055 u32 size;
1056 u32 hook_entry[NF_ARP_NUMHOOKS];
1057 u32 underflow[NF_ARP_NUMHOOKS];
1058 u32 num_counters;
1059 compat_uptr_t counters;
1060 struct compat_arpt_entry entries[0];
1061 };
1062
1063 static inline void compat_release_entry(struct compat_arpt_entry *e)
1064 {
1065 struct xt_entry_target *t;
1066
1067 t = compat_arpt_get_target(e);
1068 module_put(t->u.kernel.target->me);
1069 }
1070
1071 static int
1072 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1073 struct xt_table_info *newinfo,
1074 unsigned int *size,
1075 const unsigned char *base,
1076 const unsigned char *limit)
1077 {
1078 struct xt_entry_target *t;
1079 struct xt_target *target;
1080 unsigned int entry_offset;
1081 int ret, off;
1082
1083 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1084 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1085 (unsigned char *)e + e->next_offset > limit)
1086 return -EINVAL;
1087
1088 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1089 sizeof(struct compat_xt_entry_target))
1090 return -EINVAL;
1091
1092 if (!arp_checkentry(&e->arp))
1093 return -EINVAL;
1094
1095 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1096 e->next_offset);
1097 if (ret)
1098 return ret;
1099
1100 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1101 entry_offset = (void *)e - (void *)base;
1102
1103 t = compat_arpt_get_target(e);
1104 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1105 t->u.user.revision);
1106 if (IS_ERR(target)) {
1107 ret = PTR_ERR(target);
1108 goto out;
1109 }
1110 t->u.kernel.target = target;
1111
1112 off += xt_compat_target_offset(target);
1113 *size += off;
1114 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1115 if (ret)
1116 goto release_target;
1117
1118 return 0;
1119
1120 release_target:
1121 module_put(t->u.kernel.target->me);
1122 out:
1123 return ret;
1124 }
1125
1126 static void
1127 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1128 unsigned int *size,
1129 struct xt_table_info *newinfo, unsigned char *base)
1130 {
1131 struct xt_entry_target *t;
1132 struct xt_target *target;
1133 struct arpt_entry *de;
1134 unsigned int origsize;
1135 int h;
1136
1137 origsize = *size;
1138 de = (struct arpt_entry *)*dstptr;
1139 memcpy(de, e, sizeof(struct arpt_entry));
1140 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1141
1142 *dstptr += sizeof(struct arpt_entry);
1143 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1144
1145 de->target_offset = e->target_offset - (origsize - *size);
1146 t = compat_arpt_get_target(e);
1147 target = t->u.kernel.target;
1148 xt_compat_target_from_user(t, dstptr, size);
1149
1150 de->next_offset = e->next_offset - (origsize - *size);
1151 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1152 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1153 newinfo->hook_entry[h] -= origsize - *size;
1154 if ((unsigned char *)de - base < newinfo->underflow[h])
1155 newinfo->underflow[h] -= origsize - *size;
1156 }
1157 }
1158
1159 static int translate_compat_table(struct xt_table_info **pinfo,
1160 void **pentry0,
1161 const struct compat_arpt_replace *compatr)
1162 {
1163 unsigned int i, j;
1164 struct xt_table_info *newinfo, *info;
1165 void *pos, *entry0, *entry1;
1166 struct compat_arpt_entry *iter0;
1167 struct arpt_replace repl;
1168 unsigned int size;
1169 int ret = 0;
1170
1171 info = *pinfo;
1172 entry0 = *pentry0;
1173 size = compatr->size;
1174 info->number = compatr->num_entries;
1175
1176 j = 0;
1177 xt_compat_lock(NFPROTO_ARP);
1178 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1179 /* Walk through entries, checking offsets. */
1180 xt_entry_foreach(iter0, entry0, compatr->size) {
1181 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1182 entry0,
1183 entry0 + compatr->size);
1184 if (ret != 0)
1185 goto out_unlock;
1186 ++j;
1187 }
1188
1189 ret = -EINVAL;
1190 if (j != compatr->num_entries)
1191 goto out_unlock;
1192
1193 ret = -ENOMEM;
1194 newinfo = xt_alloc_table_info(size);
1195 if (!newinfo)
1196 goto out_unlock;
1197
1198 newinfo->number = compatr->num_entries;
1199 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1200 newinfo->hook_entry[i] = compatr->hook_entry[i];
1201 newinfo->underflow[i] = compatr->underflow[i];
1202 }
1203 entry1 = newinfo->entries;
1204 pos = entry1;
1205 size = compatr->size;
1206 xt_entry_foreach(iter0, entry0, compatr->size)
1207 compat_copy_entry_from_user(iter0, &pos, &size,
1208 newinfo, entry1);
1209
1210 /* all module references in entry0 are now gone */
1211
1212 xt_compat_flush_offsets(NFPROTO_ARP);
1213 xt_compat_unlock(NFPROTO_ARP);
1214
1215 memcpy(&repl, compatr, sizeof(*compatr));
1216
1217 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1218 repl.hook_entry[i] = newinfo->hook_entry[i];
1219 repl.underflow[i] = newinfo->underflow[i];
1220 }
1221
1222 repl.num_counters = 0;
1223 repl.counters = NULL;
1224 repl.size = newinfo->size;
1225 ret = translate_table(newinfo, entry1, &repl);
1226 if (ret)
1227 goto free_newinfo;
1228
1229 *pinfo = newinfo;
1230 *pentry0 = entry1;
1231 xt_free_table_info(info);
1232 return 0;
1233
1234 free_newinfo:
1235 xt_free_table_info(newinfo);
1236 return ret;
1237 out_unlock:
1238 xt_compat_flush_offsets(NFPROTO_ARP);
1239 xt_compat_unlock(NFPROTO_ARP);
1240 xt_entry_foreach(iter0, entry0, compatr->size) {
1241 if (j-- == 0)
1242 break;
1243 compat_release_entry(iter0);
1244 }
1245 return ret;
1246 }
1247
1248 static int compat_do_replace(struct net *net, void __user *user,
1249 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_user(&tmp, user, 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(tmp.size);
1269 if (!newinfo)
1270 return -ENOMEM;
1271
1272 loc_cpu_entry = newinfo->entries;
1273 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1274 ret = -EFAULT;
1275 goto free_newinfo;
1276 }
1277
1278 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1279 if (ret != 0)
1280 goto free_newinfo;
1281
1282 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1283 tmp.num_counters, compat_ptr(tmp.counters));
1284 if (ret)
1285 goto free_newinfo_untrans;
1286 return 0;
1287
1288 free_newinfo_untrans:
1289 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1290 cleanup_entry(iter);
1291 free_newinfo:
1292 xt_free_table_info(newinfo);
1293 return ret;
1294 }
1295
1296 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1297 unsigned int len)
1298 {
1299 int ret;
1300
1301 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1302 return -EPERM;
1303
1304 switch (cmd) {
1305 case ARPT_SO_SET_REPLACE:
1306 ret = compat_do_replace(sock_net(sk), user, len);
1307 break;
1308
1309 case ARPT_SO_SET_ADD_COUNTERS:
1310 ret = do_add_counters(sock_net(sk), user, len, 1);
1311 break;
1312
1313 default:
1314 ret = -EINVAL;
1315 }
1316
1317 return ret;
1318 }
1319
1320 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1321 compat_uint_t *size,
1322 struct xt_counters *counters,
1323 unsigned int i)
1324 {
1325 struct xt_entry_target *t;
1326 struct compat_arpt_entry __user *ce;
1327 u_int16_t target_offset, next_offset;
1328 compat_uint_t origsize;
1329 int ret;
1330
1331 origsize = *size;
1332 ce = (struct compat_arpt_entry __user *)*dstptr;
1333 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1334 copy_to_user(&ce->counters, &counters[i],
1335 sizeof(counters[i])) != 0)
1336 return -EFAULT;
1337
1338 *dstptr += sizeof(struct compat_arpt_entry);
1339 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1340
1341 target_offset = e->target_offset - (origsize - *size);
1342
1343 t = arpt_get_target(e);
1344 ret = xt_compat_target_to_user(t, dstptr, size);
1345 if (ret)
1346 return ret;
1347 next_offset = e->next_offset - (origsize - *size);
1348 if (put_user(target_offset, &ce->target_offset) != 0 ||
1349 put_user(next_offset, &ce->next_offset) != 0)
1350 return -EFAULT;
1351 return 0;
1352 }
1353
1354 static int compat_copy_entries_to_user(unsigned int total_size,
1355 struct xt_table *table,
1356 void __user *userptr)
1357 {
1358 struct xt_counters *counters;
1359 const struct xt_table_info *private = table->private;
1360 void __user *pos;
1361 unsigned int size;
1362 int ret = 0;
1363 unsigned int i = 0;
1364 struct arpt_entry *iter;
1365
1366 counters = alloc_counters(table);
1367 if (IS_ERR(counters))
1368 return PTR_ERR(counters);
1369
1370 pos = userptr;
1371 size = total_size;
1372 xt_entry_foreach(iter, private->entries, total_size) {
1373 ret = compat_copy_entry_to_user(iter, &pos,
1374 &size, counters, i++);
1375 if (ret != 0)
1376 break;
1377 }
1378 vfree(counters);
1379 return ret;
1380 }
1381
1382 struct compat_arpt_get_entries {
1383 char name[XT_TABLE_MAXNAMELEN];
1384 compat_uint_t size;
1385 struct compat_arpt_entry entrytable[0];
1386 };
1387
1388 static int compat_get_entries(struct net *net,
1389 struct compat_arpt_get_entries __user *uptr,
1390 int *len)
1391 {
1392 int ret;
1393 struct compat_arpt_get_entries get;
1394 struct xt_table *t;
1395
1396 if (*len < sizeof(get))
1397 return -EINVAL;
1398 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1399 return -EFAULT;
1400 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1401 return -EINVAL;
1402
1403 get.name[sizeof(get.name) - 1] = '\0';
1404
1405 xt_compat_lock(NFPROTO_ARP);
1406 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1407 if (t) {
1408 const struct xt_table_info *private = t->private;
1409 struct xt_table_info info;
1410
1411 ret = compat_table_info(private, &info);
1412 if (!ret && get.size == info.size) {
1413 ret = compat_copy_entries_to_user(private->size,
1414 t, uptr->entrytable);
1415 } else if (!ret)
1416 ret = -EAGAIN;
1417
1418 xt_compat_flush_offsets(NFPROTO_ARP);
1419 module_put(t->me);
1420 xt_table_unlock(t);
1421 } else
1422 ret = -ENOENT;
1423
1424 xt_compat_unlock(NFPROTO_ARP);
1425 return ret;
1426 }
1427
1428 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1429
1430 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1431 int *len)
1432 {
1433 int ret;
1434
1435 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1436 return -EPERM;
1437
1438 switch (cmd) {
1439 case ARPT_SO_GET_INFO:
1440 ret = get_info(sock_net(sk), user, len, 1);
1441 break;
1442 case ARPT_SO_GET_ENTRIES:
1443 ret = compat_get_entries(sock_net(sk), user, len);
1444 break;
1445 default:
1446 ret = do_arpt_get_ctl(sk, cmd, user, len);
1447 }
1448 return ret;
1449 }
1450 #endif
1451
1452 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1453 {
1454 int ret;
1455
1456 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1457 return -EPERM;
1458
1459 switch (cmd) {
1460 case ARPT_SO_SET_REPLACE:
1461 ret = do_replace(sock_net(sk), user, len);
1462 break;
1463
1464 case ARPT_SO_SET_ADD_COUNTERS:
1465 ret = do_add_counters(sock_net(sk), user, len, 0);
1466 break;
1467
1468 default:
1469 ret = -EINVAL;
1470 }
1471
1472 return ret;
1473 }
1474
1475 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1476 {
1477 int ret;
1478
1479 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1480 return -EPERM;
1481
1482 switch (cmd) {
1483 case ARPT_SO_GET_INFO:
1484 ret = get_info(sock_net(sk), user, len, 0);
1485 break;
1486
1487 case ARPT_SO_GET_ENTRIES:
1488 ret = get_entries(sock_net(sk), user, len);
1489 break;
1490
1491 case ARPT_SO_GET_REVISION_TARGET: {
1492 struct xt_get_revision rev;
1493
1494 if (*len != sizeof(rev)) {
1495 ret = -EINVAL;
1496 break;
1497 }
1498 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1499 ret = -EFAULT;
1500 break;
1501 }
1502 rev.name[sizeof(rev.name)-1] = 0;
1503
1504 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1505 rev.revision, 1, &ret),
1506 "arpt_%s", rev.name);
1507 break;
1508 }
1509
1510 default:
1511 ret = -EINVAL;
1512 }
1513
1514 return ret;
1515 }
1516
1517 static void __arpt_unregister_table(struct xt_table *table)
1518 {
1519 struct xt_table_info *private;
1520 void *loc_cpu_entry;
1521 struct module *table_owner = table->me;
1522 struct arpt_entry *iter;
1523
1524 private = xt_unregister_table(table);
1525
1526 /* Decrease module usage counts and free resources */
1527 loc_cpu_entry = private->entries;
1528 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1529 cleanup_entry(iter);
1530 if (private->number > private->initial_entries)
1531 module_put(table_owner);
1532 xt_free_table_info(private);
1533 }
1534
1535 int arpt_register_table(struct net *net,
1536 const struct xt_table *table,
1537 const struct arpt_replace *repl,
1538 const struct nf_hook_ops *ops,
1539 struct xt_table **res)
1540 {
1541 int ret;
1542 struct xt_table_info *newinfo;
1543 struct xt_table_info bootstrap = {0};
1544 void *loc_cpu_entry;
1545 struct xt_table *new_table;
1546
1547 newinfo = xt_alloc_table_info(repl->size);
1548 if (!newinfo)
1549 return -ENOMEM;
1550
1551 loc_cpu_entry = newinfo->entries;
1552 memcpy(loc_cpu_entry, repl->entries, repl->size);
1553
1554 ret = translate_table(newinfo, loc_cpu_entry, repl);
1555 if (ret != 0)
1556 goto out_free;
1557
1558 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1559 if (IS_ERR(new_table)) {
1560 ret = PTR_ERR(new_table);
1561 goto out_free;
1562 }
1563
1564 /* set res now, will see skbs right after nf_register_net_hooks */
1565 WRITE_ONCE(*res, new_table);
1566
1567 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1568 if (ret != 0) {
1569 __arpt_unregister_table(new_table);
1570 *res = NULL;
1571 }
1572
1573 return ret;
1574
1575 out_free:
1576 xt_free_table_info(newinfo);
1577 return ret;
1578 }
1579
1580 void arpt_unregister_table(struct net *net, struct xt_table *table,
1581 const struct nf_hook_ops *ops)
1582 {
1583 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1584 __arpt_unregister_table(table);
1585 }
1586
1587 /* The built-in targets: standard (NULL) and error. */
1588 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1589 {
1590 .name = XT_STANDARD_TARGET,
1591 .targetsize = sizeof(int),
1592 .family = NFPROTO_ARP,
1593 #ifdef CONFIG_COMPAT
1594 .compatsize = sizeof(compat_int_t),
1595 .compat_from_user = compat_standard_from_user,
1596 .compat_to_user = compat_standard_to_user,
1597 #endif
1598 },
1599 {
1600 .name = XT_ERROR_TARGET,
1601 .target = arpt_error,
1602 .targetsize = XT_FUNCTION_MAXNAMELEN,
1603 .family = NFPROTO_ARP,
1604 },
1605 };
1606
1607 static struct nf_sockopt_ops arpt_sockopts = {
1608 .pf = PF_INET,
1609 .set_optmin = ARPT_BASE_CTL,
1610 .set_optmax = ARPT_SO_SET_MAX+1,
1611 .set = do_arpt_set_ctl,
1612 #ifdef CONFIG_COMPAT
1613 .compat_set = compat_do_arpt_set_ctl,
1614 #endif
1615 .get_optmin = ARPT_BASE_CTL,
1616 .get_optmax = ARPT_SO_GET_MAX+1,
1617 .get = do_arpt_get_ctl,
1618 #ifdef CONFIG_COMPAT
1619 .compat_get = compat_do_arpt_get_ctl,
1620 #endif
1621 .owner = THIS_MODULE,
1622 };
1623
1624 static int __net_init arp_tables_net_init(struct net *net)
1625 {
1626 return xt_proto_init(net, NFPROTO_ARP);
1627 }
1628
1629 static void __net_exit arp_tables_net_exit(struct net *net)
1630 {
1631 xt_proto_fini(net, NFPROTO_ARP);
1632 }
1633
1634 static struct pernet_operations arp_tables_net_ops = {
1635 .init = arp_tables_net_init,
1636 .exit = arp_tables_net_exit,
1637 };
1638
1639 static int __init arp_tables_init(void)
1640 {
1641 int ret;
1642
1643 ret = register_pernet_subsys(&arp_tables_net_ops);
1644 if (ret < 0)
1645 goto err1;
1646
1647 /* No one else will be downing sem now, so we won't sleep */
1648 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1649 if (ret < 0)
1650 goto err2;
1651
1652 /* Register setsockopt */
1653 ret = nf_register_sockopt(&arpt_sockopts);
1654 if (ret < 0)
1655 goto err4;
1656
1657 pr_info("arp_tables: (C) 2002 David S. Miller\n");
1658 return 0;
1659
1660 err4:
1661 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1662 err2:
1663 unregister_pernet_subsys(&arp_tables_net_ops);
1664 err1:
1665 return ret;
1666 }
1667
1668 static void __exit arp_tables_fini(void)
1669 {
1670 nf_unregister_sockopt(&arpt_sockopts);
1671 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1672 unregister_pernet_subsys(&arp_tables_net_ops);
1673 }
1674
1675 EXPORT_SYMBOL(arpt_register_table);
1676 EXPORT_SYMBOL(arpt_unregister_table);
1677 EXPORT_SYMBOL(arpt_do_table);
1678
1679 module_init(arp_tables_init);
1680 module_exit(arp_tables_fini);
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