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netfilter: arp_tables: fix invoking 32bit "iptable -P INPUT ACCEPT" failed in 64bit...
[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.net = state->net;
221 acpar.in = state->in;
222 acpar.out = state->out;
223 acpar.hooknum = hook;
224 acpar.family = NFPROTO_ARP;
225 acpar.hotdrop = false;
226
227 arp = arp_hdr(skb);
228 do {
229 const struct xt_entry_target *t;
230 struct xt_counters *counter;
231
232 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
233 e = arpt_next_entry(e);
234 continue;
235 }
236
237 counter = xt_get_this_cpu_counter(&e->counters);
238 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
239
240 t = arpt_get_target_c(e);
241
242 /* Standard target? */
243 if (!t->u.kernel.target->target) {
244 int v;
245
246 v = ((struct xt_standard_target *)t)->verdict;
247 if (v < 0) {
248 /* Pop from stack? */
249 if (v != XT_RETURN) {
250 verdict = (unsigned int)(-v) - 1;
251 break;
252 }
253 if (stackidx == 0) {
254 e = get_entry(table_base,
255 private->underflow[hook]);
256 } else {
257 e = jumpstack[--stackidx];
258 e = arpt_next_entry(e);
259 }
260 continue;
261 }
262 if (table_base + v
263 != arpt_next_entry(e)) {
264 jumpstack[stackidx++] = e;
265 }
266
267 e = get_entry(table_base, v);
268 continue;
269 }
270
271 acpar.target = t->u.kernel.target;
272 acpar.targinfo = t->data;
273 verdict = t->u.kernel.target->target(skb, &acpar);
274
275 /* Target might have changed stuff. */
276 arp = arp_hdr(skb);
277
278 if (verdict == XT_CONTINUE)
279 e = arpt_next_entry(e);
280 else
281 /* Verdict */
282 break;
283 } while (!acpar.hotdrop);
284 xt_write_recseq_end(addend);
285 local_bh_enable();
286
287 if (acpar.hotdrop)
288 return NF_DROP;
289 else
290 return verdict;
291 }
292
293 /* All zeroes == unconditional rule. */
294 static inline bool unconditional(const struct arpt_entry *e)
295 {
296 static const struct arpt_arp uncond;
297
298 return e->target_offset == sizeof(struct arpt_entry) &&
299 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
300 }
301
302 /* Figures out from what hook each rule can be called: returns 0 if
303 * there are loops. Puts hook bitmask in comefrom.
304 */
305 static int mark_source_chains(const struct xt_table_info *newinfo,
306 unsigned int valid_hooks, void *entry0,
307 unsigned int *offsets)
308 {
309 unsigned int hook;
310
311 /* No recursion; use packet counter to save back ptrs (reset
312 * to 0 as we leave), and comefrom to save source hook bitmask.
313 */
314 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
315 unsigned int pos = newinfo->hook_entry[hook];
316 struct arpt_entry *e
317 = (struct arpt_entry *)(entry0 + pos);
318
319 if (!(valid_hooks & (1 << hook)))
320 continue;
321
322 /* Set initial back pointer. */
323 e->counters.pcnt = pos;
324
325 for (;;) {
326 const struct xt_standard_target *t
327 = (void *)arpt_get_target_c(e);
328 int visited = e->comefrom & (1 << hook);
329
330 if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
331 return 0;
332
333 e->comefrom
334 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
335
336 /* Unconditional return/END. */
337 if ((unconditional(e) &&
338 (strcmp(t->target.u.user.name,
339 XT_STANDARD_TARGET) == 0) &&
340 t->verdict < 0) || visited) {
341 unsigned int oldpos, size;
342
343 if ((strcmp(t->target.u.user.name,
344 XT_STANDARD_TARGET) == 0) &&
345 t->verdict < -NF_MAX_VERDICT - 1)
346 return 0;
347
348 /* Return: backtrack through the last
349 * big jump.
350 */
351 do {
352 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
353 oldpos = pos;
354 pos = e->counters.pcnt;
355 e->counters.pcnt = 0;
356
357 /* We're at the start. */
358 if (pos == oldpos)
359 goto next;
360
361 e = (struct arpt_entry *)
362 (entry0 + pos);
363 } while (oldpos == pos + e->next_offset);
364
365 /* Move along one */
366 size = e->next_offset;
367 e = (struct arpt_entry *)
368 (entry0 + pos + size);
369 if (pos + size >= newinfo->size)
370 return 0;
371 e->counters.pcnt = pos;
372 pos += size;
373 } else {
374 int newpos = t->verdict;
375
376 if (strcmp(t->target.u.user.name,
377 XT_STANDARD_TARGET) == 0 &&
378 newpos >= 0) {
379 /* This a jump; chase it. */
380 if (!xt_find_jump_offset(offsets, newpos,
381 newinfo->number))
382 return 0;
383 e = (struct arpt_entry *)
384 (entry0 + newpos);
385 } else {
386 /* ... this is a fallthru */
387 newpos = pos + e->next_offset;
388 if (newpos >= newinfo->size)
389 return 0;
390 }
391 e = (struct arpt_entry *)
392 (entry0 + newpos);
393 e->counters.pcnt = pos;
394 pos = newpos;
395 }
396 }
397 next: ;
398 }
399 return 1;
400 }
401
402 static inline int check_target(struct arpt_entry *e, const char *name)
403 {
404 struct xt_entry_target *t = arpt_get_target(e);
405 struct xt_tgchk_param par = {
406 .table = name,
407 .entryinfo = e,
408 .target = t->u.kernel.target,
409 .targinfo = t->data,
410 .hook_mask = e->comefrom,
411 .family = NFPROTO_ARP,
412 };
413
414 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
415 }
416
417 static inline int
418 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
419 {
420 struct xt_entry_target *t;
421 struct xt_target *target;
422 unsigned long pcnt;
423 int ret;
424
425 pcnt = xt_percpu_counter_alloc();
426 if (IS_ERR_VALUE(pcnt))
427 return -ENOMEM;
428 e->counters.pcnt = pcnt;
429
430 t = arpt_get_target(e);
431 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
432 t->u.user.revision);
433 if (IS_ERR(target)) {
434 ret = PTR_ERR(target);
435 goto out;
436 }
437 t->u.kernel.target = target;
438
439 ret = check_target(e, name);
440 if (ret)
441 goto err;
442 return 0;
443 err:
444 module_put(t->u.kernel.target->me);
445 out:
446 xt_percpu_counter_free(e->counters.pcnt);
447
448 return ret;
449 }
450
451 static bool check_underflow(const struct arpt_entry *e)
452 {
453 const struct xt_entry_target *t;
454 unsigned int verdict;
455
456 if (!unconditional(e))
457 return false;
458 t = arpt_get_target_c(e);
459 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
460 return false;
461 verdict = ((struct xt_standard_target *)t)->verdict;
462 verdict = -verdict - 1;
463 return verdict == NF_DROP || verdict == NF_ACCEPT;
464 }
465
466 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
467 struct xt_table_info *newinfo,
468 const unsigned char *base,
469 const unsigned char *limit,
470 const unsigned int *hook_entries,
471 const unsigned int *underflows,
472 unsigned int valid_hooks)
473 {
474 unsigned int h;
475 int err;
476
477 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
478 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
479 (unsigned char *)e + e->next_offset > limit)
480 return -EINVAL;
481
482 if (e->next_offset
483 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
484 return -EINVAL;
485
486 if (!arp_checkentry(&e->arp))
487 return -EINVAL;
488
489 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
490 e->next_offset);
491 if (err)
492 return err;
493
494 /* Check hooks & underflows */
495 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
496 if (!(valid_hooks & (1 << h)))
497 continue;
498 if ((unsigned char *)e - base == hook_entries[h])
499 newinfo->hook_entry[h] = hook_entries[h];
500 if ((unsigned char *)e - base == underflows[h]) {
501 if (!check_underflow(e))
502 return -EINVAL;
503
504 newinfo->underflow[h] = underflows[h];
505 }
506 }
507
508 /* Clear counters and comefrom */
509 e->counters = ((struct xt_counters) { 0, 0 });
510 e->comefrom = 0;
511 return 0;
512 }
513
514 static inline void cleanup_entry(struct arpt_entry *e)
515 {
516 struct xt_tgdtor_param par;
517 struct xt_entry_target *t;
518
519 t = arpt_get_target(e);
520 par.target = t->u.kernel.target;
521 par.targinfo = t->data;
522 par.family = NFPROTO_ARP;
523 if (par.target->destroy != NULL)
524 par.target->destroy(&par);
525 module_put(par.target->me);
526 xt_percpu_counter_free(e->counters.pcnt);
527 }
528
529 /* Checks and translates the user-supplied table segment (held in
530 * newinfo).
531 */
532 static int translate_table(struct xt_table_info *newinfo, void *entry0,
533 const struct arpt_replace *repl)
534 {
535 struct arpt_entry *iter;
536 unsigned int *offsets;
537 unsigned int i;
538 int ret = 0;
539
540 newinfo->size = repl->size;
541 newinfo->number = repl->num_entries;
542
543 /* Init all hooks to impossible value. */
544 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
545 newinfo->hook_entry[i] = 0xFFFFFFFF;
546 newinfo->underflow[i] = 0xFFFFFFFF;
547 }
548
549 offsets = xt_alloc_entry_offsets(newinfo->number);
550 if (!offsets)
551 return -ENOMEM;
552 i = 0;
553
554 /* Walk through entries, checking offsets. */
555 xt_entry_foreach(iter, entry0, newinfo->size) {
556 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
557 entry0 + repl->size,
558 repl->hook_entry,
559 repl->underflow,
560 repl->valid_hooks);
561 if (ret != 0)
562 goto out_free;
563 if (i < repl->num_entries)
564 offsets[i] = (void *)iter - entry0;
565 ++i;
566 if (strcmp(arpt_get_target(iter)->u.user.name,
567 XT_ERROR_TARGET) == 0)
568 ++newinfo->stacksize;
569 }
570 if (ret != 0)
571 goto out_free;
572
573 ret = -EINVAL;
574 if (i != repl->num_entries)
575 goto out_free;
576
577 /* Check hooks all assigned */
578 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
579 /* Only hooks which are valid */
580 if (!(repl->valid_hooks & (1 << i)))
581 continue;
582 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
583 goto out_free;
584 if (newinfo->underflow[i] == 0xFFFFFFFF)
585 goto out_free;
586 }
587
588 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
589 ret = -ELOOP;
590 goto out_free;
591 }
592 kvfree(offsets);
593
594 /* Finally, each sanity check must pass */
595 i = 0;
596 xt_entry_foreach(iter, entry0, newinfo->size) {
597 ret = find_check_entry(iter, repl->name, repl->size);
598 if (ret != 0)
599 break;
600 ++i;
601 }
602
603 if (ret != 0) {
604 xt_entry_foreach(iter, entry0, newinfo->size) {
605 if (i-- == 0)
606 break;
607 cleanup_entry(iter);
608 }
609 return ret;
610 }
611
612 return ret;
613 out_free:
614 kvfree(offsets);
615 return ret;
616 }
617
618 static void get_counters(const struct xt_table_info *t,
619 struct xt_counters counters[])
620 {
621 struct arpt_entry *iter;
622 unsigned int cpu;
623 unsigned int i;
624
625 for_each_possible_cpu(cpu) {
626 seqcount_t *s = &per_cpu(xt_recseq, cpu);
627
628 i = 0;
629 xt_entry_foreach(iter, t->entries, t->size) {
630 struct xt_counters *tmp;
631 u64 bcnt, pcnt;
632 unsigned int start;
633
634 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
635 do {
636 start = read_seqcount_begin(s);
637 bcnt = tmp->bcnt;
638 pcnt = tmp->pcnt;
639 } while (read_seqcount_retry(s, start));
640
641 ADD_COUNTER(counters[i], bcnt, pcnt);
642 ++i;
643 }
644 }
645 }
646
647 static struct xt_counters *alloc_counters(const struct xt_table *table)
648 {
649 unsigned int countersize;
650 struct xt_counters *counters;
651 const struct xt_table_info *private = table->private;
652
653 /* We need atomic snapshot of counters: rest doesn't change
654 * (other than comefrom, which userspace doesn't care
655 * about).
656 */
657 countersize = sizeof(struct xt_counters) * private->number;
658 counters = vzalloc(countersize);
659
660 if (counters == NULL)
661 return ERR_PTR(-ENOMEM);
662
663 get_counters(private, counters);
664
665 return counters;
666 }
667
668 static int copy_entries_to_user(unsigned int total_size,
669 const struct xt_table *table,
670 void __user *userptr)
671 {
672 unsigned int off, num;
673 const struct arpt_entry *e;
674 struct xt_counters *counters;
675 struct xt_table_info *private = table->private;
676 int ret = 0;
677 void *loc_cpu_entry;
678
679 counters = alloc_counters(table);
680 if (IS_ERR(counters))
681 return PTR_ERR(counters);
682
683 loc_cpu_entry = private->entries;
684 /* ... then copy entire thing ... */
685 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
686 ret = -EFAULT;
687 goto free_counters;
688 }
689
690 /* FIXME: use iterator macros --RR */
691 /* ... then go back and fix counters and names */
692 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
693 const struct xt_entry_target *t;
694
695 e = (struct arpt_entry *)(loc_cpu_entry + off);
696 if (copy_to_user(userptr + off
697 + offsetof(struct arpt_entry, counters),
698 &counters[num],
699 sizeof(counters[num])) != 0) {
700 ret = -EFAULT;
701 goto free_counters;
702 }
703
704 t = arpt_get_target_c(e);
705 if (copy_to_user(userptr + off + e->target_offset
706 + offsetof(struct xt_entry_target,
707 u.user.name),
708 t->u.kernel.target->name,
709 strlen(t->u.kernel.target->name)+1) != 0) {
710 ret = -EFAULT;
711 goto free_counters;
712 }
713 }
714
715 free_counters:
716 vfree(counters);
717 return ret;
718 }
719
720 #ifdef CONFIG_COMPAT
721 static void compat_standard_from_user(void *dst, const void *src)
722 {
723 int v = *(compat_int_t *)src;
724
725 if (v > 0)
726 v += xt_compat_calc_jump(NFPROTO_ARP, v);
727 memcpy(dst, &v, sizeof(v));
728 }
729
730 static int compat_standard_to_user(void __user *dst, const void *src)
731 {
732 compat_int_t cv = *(int *)src;
733
734 if (cv > 0)
735 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
736 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
737 }
738
739 static int compat_calc_entry(const struct arpt_entry *e,
740 const struct xt_table_info *info,
741 const void *base, struct xt_table_info *newinfo)
742 {
743 const struct xt_entry_target *t;
744 unsigned int entry_offset;
745 int off, i, ret;
746
747 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
748 entry_offset = (void *)e - base;
749
750 t = arpt_get_target_c(e);
751 off += xt_compat_target_offset(t->u.kernel.target);
752 newinfo->size -= off;
753 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
754 if (ret)
755 return ret;
756
757 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
758 if (info->hook_entry[i] &&
759 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
760 newinfo->hook_entry[i] -= off;
761 if (info->underflow[i] &&
762 (e < (struct arpt_entry *)(base + info->underflow[i])))
763 newinfo->underflow[i] -= off;
764 }
765 return 0;
766 }
767
768 static int compat_table_info(const struct xt_table_info *info,
769 struct xt_table_info *newinfo)
770 {
771 struct arpt_entry *iter;
772 const void *loc_cpu_entry;
773 int ret;
774
775 if (!newinfo || !info)
776 return -EINVAL;
777
778 /* we dont care about newinfo->entries */
779 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
780 newinfo->initial_entries = 0;
781 loc_cpu_entry = info->entries;
782 xt_compat_init_offsets(NFPROTO_ARP, info->number);
783 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
784 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
785 if (ret != 0)
786 return ret;
787 }
788 return 0;
789 }
790 #endif
791
792 static int get_info(struct net *net, void __user *user,
793 const int *len, int compat)
794 {
795 char name[XT_TABLE_MAXNAMELEN];
796 struct xt_table *t;
797 int ret;
798
799 if (*len != sizeof(struct arpt_getinfo))
800 return -EINVAL;
801
802 if (copy_from_user(name, user, sizeof(name)) != 0)
803 return -EFAULT;
804
805 name[XT_TABLE_MAXNAMELEN-1] = '\0';
806 #ifdef CONFIG_COMPAT
807 if (compat)
808 xt_compat_lock(NFPROTO_ARP);
809 #endif
810 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
811 "arptable_%s", name);
812 if (!IS_ERR_OR_NULL(t)) {
813 struct arpt_getinfo info;
814 const struct xt_table_info *private = t->private;
815 #ifdef CONFIG_COMPAT
816 struct xt_table_info tmp;
817
818 if (compat) {
819 ret = compat_table_info(private, &tmp);
820 xt_compat_flush_offsets(NFPROTO_ARP);
821 private = &tmp;
822 }
823 #endif
824 memset(&info, 0, sizeof(info));
825 info.valid_hooks = t->valid_hooks;
826 memcpy(info.hook_entry, private->hook_entry,
827 sizeof(info.hook_entry));
828 memcpy(info.underflow, private->underflow,
829 sizeof(info.underflow));
830 info.num_entries = private->number;
831 info.size = private->size;
832 strcpy(info.name, name);
833
834 if (copy_to_user(user, &info, *len) != 0)
835 ret = -EFAULT;
836 else
837 ret = 0;
838 xt_table_unlock(t);
839 module_put(t->me);
840 } else
841 ret = t ? PTR_ERR(t) : -ENOENT;
842 #ifdef CONFIG_COMPAT
843 if (compat)
844 xt_compat_unlock(NFPROTO_ARP);
845 #endif
846 return ret;
847 }
848
849 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
850 const int *len)
851 {
852 int ret;
853 struct arpt_get_entries get;
854 struct xt_table *t;
855
856 if (*len < sizeof(get))
857 return -EINVAL;
858 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
859 return -EFAULT;
860 if (*len != sizeof(struct arpt_get_entries) + get.size)
861 return -EINVAL;
862
863 get.name[sizeof(get.name) - 1] = '\0';
864
865 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
866 if (!IS_ERR_OR_NULL(t)) {
867 const struct xt_table_info *private = t->private;
868
869 if (get.size == private->size)
870 ret = copy_entries_to_user(private->size,
871 t, uptr->entrytable);
872 else
873 ret = -EAGAIN;
874
875 module_put(t->me);
876 xt_table_unlock(t);
877 } else
878 ret = t ? PTR_ERR(t) : -ENOENT;
879
880 return ret;
881 }
882
883 static int __do_replace(struct net *net, const char *name,
884 unsigned int valid_hooks,
885 struct xt_table_info *newinfo,
886 unsigned int num_counters,
887 void __user *counters_ptr)
888 {
889 int ret;
890 struct xt_table *t;
891 struct xt_table_info *oldinfo;
892 struct xt_counters *counters;
893 void *loc_cpu_old_entry;
894 struct arpt_entry *iter;
895
896 ret = 0;
897 counters = vzalloc(num_counters * sizeof(struct xt_counters));
898 if (!counters) {
899 ret = -ENOMEM;
900 goto out;
901 }
902
903 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
904 "arptable_%s", name);
905 if (IS_ERR_OR_NULL(t)) {
906 ret = t ? PTR_ERR(t) : -ENOENT;
907 goto free_newinfo_counters_untrans;
908 }
909
910 /* You lied! */
911 if (valid_hooks != t->valid_hooks) {
912 ret = -EINVAL;
913 goto put_module;
914 }
915
916 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
917 if (!oldinfo)
918 goto put_module;
919
920 /* Update module usage count based on number of rules */
921 if ((oldinfo->number > oldinfo->initial_entries) ||
922 (newinfo->number <= oldinfo->initial_entries))
923 module_put(t->me);
924 if ((oldinfo->number > oldinfo->initial_entries) &&
925 (newinfo->number <= oldinfo->initial_entries))
926 module_put(t->me);
927
928 /* Get the old counters, and synchronize with replace */
929 get_counters(oldinfo, counters);
930
931 /* Decrease module usage counts and free resource */
932 loc_cpu_old_entry = oldinfo->entries;
933 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
934 cleanup_entry(iter);
935
936 xt_free_table_info(oldinfo);
937 if (copy_to_user(counters_ptr, counters,
938 sizeof(struct xt_counters) * num_counters) != 0) {
939 /* Silent error, can't fail, new table is already in place */
940 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
941 }
942 vfree(counters);
943 xt_table_unlock(t);
944 return ret;
945
946 put_module:
947 module_put(t->me);
948 xt_table_unlock(t);
949 free_newinfo_counters_untrans:
950 vfree(counters);
951 out:
952 return ret;
953 }
954
955 static int do_replace(struct net *net, const void __user *user,
956 unsigned int len)
957 {
958 int ret;
959 struct arpt_replace tmp;
960 struct xt_table_info *newinfo;
961 void *loc_cpu_entry;
962 struct arpt_entry *iter;
963
964 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
965 return -EFAULT;
966
967 /* overflow check */
968 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
969 return -ENOMEM;
970 if (tmp.num_counters == 0)
971 return -EINVAL;
972
973 tmp.name[sizeof(tmp.name)-1] = 0;
974
975 newinfo = xt_alloc_table_info(tmp.size);
976 if (!newinfo)
977 return -ENOMEM;
978
979 loc_cpu_entry = newinfo->entries;
980 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
981 tmp.size) != 0) {
982 ret = -EFAULT;
983 goto free_newinfo;
984 }
985
986 ret = translate_table(newinfo, loc_cpu_entry, &tmp);
987 if (ret != 0)
988 goto free_newinfo;
989
990 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
991 tmp.num_counters, tmp.counters);
992 if (ret)
993 goto free_newinfo_untrans;
994 return 0;
995
996 free_newinfo_untrans:
997 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
998 cleanup_entry(iter);
999 free_newinfo:
1000 xt_free_table_info(newinfo);
1001 return ret;
1002 }
1003
1004 static int do_add_counters(struct net *net, const void __user *user,
1005 unsigned int len, int compat)
1006 {
1007 unsigned int i;
1008 struct xt_counters_info tmp;
1009 struct xt_counters *paddc;
1010 struct xt_table *t;
1011 const struct xt_table_info *private;
1012 int ret = 0;
1013 struct arpt_entry *iter;
1014 unsigned int addend;
1015
1016 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1017 if (IS_ERR(paddc))
1018 return PTR_ERR(paddc);
1019
1020 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1021 if (IS_ERR_OR_NULL(t)) {
1022 ret = t ? PTR_ERR(t) : -ENOENT;
1023 goto free;
1024 }
1025
1026 local_bh_disable();
1027 private = t->private;
1028 if (private->number != tmp.num_counters) {
1029 ret = -EINVAL;
1030 goto unlock_up_free;
1031 }
1032
1033 i = 0;
1034
1035 addend = xt_write_recseq_begin();
1036 xt_entry_foreach(iter, private->entries, private->size) {
1037 struct xt_counters *tmp;
1038
1039 tmp = xt_get_this_cpu_counter(&iter->counters);
1040 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1041 ++i;
1042 }
1043 xt_write_recseq_end(addend);
1044 unlock_up_free:
1045 local_bh_enable();
1046 xt_table_unlock(t);
1047 module_put(t->me);
1048 free:
1049 vfree(paddc);
1050
1051 return ret;
1052 }
1053
1054 #ifdef CONFIG_COMPAT
1055 struct compat_arpt_replace {
1056 char name[XT_TABLE_MAXNAMELEN];
1057 u32 valid_hooks;
1058 u32 num_entries;
1059 u32 size;
1060 u32 hook_entry[NF_ARP_NUMHOOKS];
1061 u32 underflow[NF_ARP_NUMHOOKS];
1062 u32 num_counters;
1063 compat_uptr_t counters;
1064 struct compat_arpt_entry entries[0];
1065 };
1066
1067 static inline void compat_release_entry(struct compat_arpt_entry *e)
1068 {
1069 struct xt_entry_target *t;
1070
1071 t = compat_arpt_get_target(e);
1072 module_put(t->u.kernel.target->me);
1073 }
1074
1075 static int
1076 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1077 struct xt_table_info *newinfo,
1078 unsigned int *size,
1079 const unsigned char *base,
1080 const unsigned char *limit)
1081 {
1082 struct xt_entry_target *t;
1083 struct xt_target *target;
1084 unsigned int entry_offset;
1085 int ret, off;
1086
1087 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1088 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1089 (unsigned char *)e + e->next_offset > limit)
1090 return -EINVAL;
1091
1092 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1093 sizeof(struct compat_xt_entry_target))
1094 return -EINVAL;
1095
1096 if (!arp_checkentry(&e->arp))
1097 return -EINVAL;
1098
1099 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1100 e->next_offset);
1101 if (ret)
1102 return ret;
1103
1104 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1105 entry_offset = (void *)e - (void *)base;
1106
1107 t = compat_arpt_get_target(e);
1108 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1109 t->u.user.revision);
1110 if (IS_ERR(target)) {
1111 ret = PTR_ERR(target);
1112 goto out;
1113 }
1114 t->u.kernel.target = target;
1115
1116 off += xt_compat_target_offset(target);
1117 *size += off;
1118 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1119 if (ret)
1120 goto release_target;
1121
1122 return 0;
1123
1124 release_target:
1125 module_put(t->u.kernel.target->me);
1126 out:
1127 return ret;
1128 }
1129
1130 static void
1131 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1132 unsigned int *size,
1133 struct xt_table_info *newinfo, unsigned char *base)
1134 {
1135 struct xt_entry_target *t;
1136 struct xt_target *target;
1137 struct arpt_entry *de;
1138 unsigned int origsize;
1139 int h;
1140
1141 origsize = *size;
1142 de = (struct arpt_entry *)*dstptr;
1143 memcpy(de, e, sizeof(struct arpt_entry));
1144 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1145
1146 *dstptr += sizeof(struct arpt_entry);
1147 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1148
1149 de->target_offset = e->target_offset - (origsize - *size);
1150 t = compat_arpt_get_target(e);
1151 target = t->u.kernel.target;
1152 xt_compat_target_from_user(t, dstptr, size);
1153
1154 de->next_offset = e->next_offset - (origsize - *size);
1155 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1156 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1157 newinfo->hook_entry[h] -= origsize - *size;
1158 if ((unsigned char *)de - base < newinfo->underflow[h])
1159 newinfo->underflow[h] -= origsize - *size;
1160 }
1161 }
1162
1163 static int translate_compat_table(struct xt_table_info **pinfo,
1164 void **pentry0,
1165 const struct compat_arpt_replace *compatr)
1166 {
1167 unsigned int i, j;
1168 struct xt_table_info *newinfo, *info;
1169 void *pos, *entry0, *entry1;
1170 struct compat_arpt_entry *iter0;
1171 struct arpt_replace repl;
1172 unsigned int size;
1173 int ret = 0;
1174
1175 info = *pinfo;
1176 entry0 = *pentry0;
1177 size = compatr->size;
1178 info->number = compatr->num_entries;
1179
1180 j = 0;
1181 xt_compat_lock(NFPROTO_ARP);
1182 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1183 /* Walk through entries, checking offsets. */
1184 xt_entry_foreach(iter0, entry0, compatr->size) {
1185 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1186 entry0,
1187 entry0 + compatr->size);
1188 if (ret != 0)
1189 goto out_unlock;
1190 ++j;
1191 }
1192
1193 ret = -EINVAL;
1194 if (j != compatr->num_entries)
1195 goto out_unlock;
1196
1197 ret = -ENOMEM;
1198 newinfo = xt_alloc_table_info(size);
1199 if (!newinfo)
1200 goto out_unlock;
1201
1202 newinfo->number = compatr->num_entries;
1203 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1204 newinfo->hook_entry[i] = compatr->hook_entry[i];
1205 newinfo->underflow[i] = compatr->underflow[i];
1206 }
1207 entry1 = newinfo->entries;
1208 pos = entry1;
1209 size = compatr->size;
1210 xt_entry_foreach(iter0, entry0, compatr->size)
1211 compat_copy_entry_from_user(iter0, &pos, &size,
1212 newinfo, entry1);
1213
1214 /* all module references in entry0 are now gone */
1215
1216 xt_compat_flush_offsets(NFPROTO_ARP);
1217 xt_compat_unlock(NFPROTO_ARP);
1218
1219 memcpy(&repl, compatr, sizeof(*compatr));
1220
1221 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1222 repl.hook_entry[i] = newinfo->hook_entry[i];
1223 repl.underflow[i] = newinfo->underflow[i];
1224 }
1225
1226 repl.num_counters = 0;
1227 repl.counters = NULL;
1228 repl.size = newinfo->size;
1229 ret = translate_table(newinfo, entry1, &repl);
1230 if (ret)
1231 goto free_newinfo;
1232
1233 *pinfo = newinfo;
1234 *pentry0 = entry1;
1235 xt_free_table_info(info);
1236 return 0;
1237
1238 free_newinfo:
1239 xt_free_table_info(newinfo);
1240 return ret;
1241 out_unlock:
1242 xt_compat_flush_offsets(NFPROTO_ARP);
1243 xt_compat_unlock(NFPROTO_ARP);
1244 xt_entry_foreach(iter0, entry0, compatr->size) {
1245 if (j-- == 0)
1246 break;
1247 compat_release_entry(iter0);
1248 }
1249 return ret;
1250 }
1251
1252 static int compat_do_replace(struct net *net, void __user *user,
1253 unsigned int len)
1254 {
1255 int ret;
1256 struct compat_arpt_replace tmp;
1257 struct xt_table_info *newinfo;
1258 void *loc_cpu_entry;
1259 struct arpt_entry *iter;
1260
1261 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1262 return -EFAULT;
1263
1264 /* overflow check */
1265 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1266 return -ENOMEM;
1267 if (tmp.num_counters == 0)
1268 return -EINVAL;
1269
1270 tmp.name[sizeof(tmp.name)-1] = 0;
1271
1272 newinfo = xt_alloc_table_info(tmp.size);
1273 if (!newinfo)
1274 return -ENOMEM;
1275
1276 loc_cpu_entry = newinfo->entries;
1277 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1278 ret = -EFAULT;
1279 goto free_newinfo;
1280 }
1281
1282 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1283 if (ret != 0)
1284 goto free_newinfo;
1285
1286 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1287 tmp.num_counters, compat_ptr(tmp.counters));
1288 if (ret)
1289 goto free_newinfo_untrans;
1290 return 0;
1291
1292 free_newinfo_untrans:
1293 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1294 cleanup_entry(iter);
1295 free_newinfo:
1296 xt_free_table_info(newinfo);
1297 return ret;
1298 }
1299
1300 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1301 unsigned int len)
1302 {
1303 int ret;
1304
1305 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1306 return -EPERM;
1307
1308 switch (cmd) {
1309 case ARPT_SO_SET_REPLACE:
1310 ret = compat_do_replace(sock_net(sk), user, len);
1311 break;
1312
1313 case ARPT_SO_SET_ADD_COUNTERS:
1314 ret = do_add_counters(sock_net(sk), user, len, 1);
1315 break;
1316
1317 default:
1318 ret = -EINVAL;
1319 }
1320
1321 return ret;
1322 }
1323
1324 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1325 compat_uint_t *size,
1326 struct xt_counters *counters,
1327 unsigned int i)
1328 {
1329 struct xt_entry_target *t;
1330 struct compat_arpt_entry __user *ce;
1331 u_int16_t target_offset, next_offset;
1332 compat_uint_t origsize;
1333 int ret;
1334
1335 origsize = *size;
1336 ce = (struct compat_arpt_entry __user *)*dstptr;
1337 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1338 copy_to_user(&ce->counters, &counters[i],
1339 sizeof(counters[i])) != 0)
1340 return -EFAULT;
1341
1342 *dstptr += sizeof(struct compat_arpt_entry);
1343 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1344
1345 target_offset = e->target_offset - (origsize - *size);
1346
1347 t = arpt_get_target(e);
1348 ret = xt_compat_target_to_user(t, dstptr, size);
1349 if (ret)
1350 return ret;
1351 next_offset = e->next_offset - (origsize - *size);
1352 if (put_user(target_offset, &ce->target_offset) != 0 ||
1353 put_user(next_offset, &ce->next_offset) != 0)
1354 return -EFAULT;
1355 return 0;
1356 }
1357
1358 static int compat_copy_entries_to_user(unsigned int total_size,
1359 struct xt_table *table,
1360 void __user *userptr)
1361 {
1362 struct xt_counters *counters;
1363 const struct xt_table_info *private = table->private;
1364 void __user *pos;
1365 unsigned int size;
1366 int ret = 0;
1367 unsigned int i = 0;
1368 struct arpt_entry *iter;
1369
1370 counters = alloc_counters(table);
1371 if (IS_ERR(counters))
1372 return PTR_ERR(counters);
1373
1374 pos = userptr;
1375 size = total_size;
1376 xt_entry_foreach(iter, private->entries, total_size) {
1377 ret = compat_copy_entry_to_user(iter, &pos,
1378 &size, counters, i++);
1379 if (ret != 0)
1380 break;
1381 }
1382 vfree(counters);
1383 return ret;
1384 }
1385
1386 struct compat_arpt_get_entries {
1387 char name[XT_TABLE_MAXNAMELEN];
1388 compat_uint_t size;
1389 struct compat_arpt_entry entrytable[0];
1390 };
1391
1392 static int compat_get_entries(struct net *net,
1393 struct compat_arpt_get_entries __user *uptr,
1394 int *len)
1395 {
1396 int ret;
1397 struct compat_arpt_get_entries get;
1398 struct xt_table *t;
1399
1400 if (*len < sizeof(get))
1401 return -EINVAL;
1402 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1403 return -EFAULT;
1404 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1405 return -EINVAL;
1406
1407 get.name[sizeof(get.name) - 1] = '\0';
1408
1409 xt_compat_lock(NFPROTO_ARP);
1410 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1411 if (!IS_ERR_OR_NULL(t)) {
1412 const struct xt_table_info *private = t->private;
1413 struct xt_table_info info;
1414
1415 ret = compat_table_info(private, &info);
1416 if (!ret && get.size == info.size) {
1417 ret = compat_copy_entries_to_user(private->size,
1418 t, uptr->entrytable);
1419 } else if (!ret)
1420 ret = -EAGAIN;
1421
1422 xt_compat_flush_offsets(NFPROTO_ARP);
1423 module_put(t->me);
1424 xt_table_unlock(t);
1425 } else
1426 ret = t ? PTR_ERR(t) : -ENOENT;
1427
1428 xt_compat_unlock(NFPROTO_ARP);
1429 return ret;
1430 }
1431
1432 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1433
1434 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1435 int *len)
1436 {
1437 int ret;
1438
1439 if (!ns_capable(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(sock_net(sk), user, len, 1);
1445 break;
1446 case ARPT_SO_GET_ENTRIES:
1447 ret = compat_get_entries(sock_net(sk), user, len);
1448 break;
1449 default:
1450 ret = do_arpt_get_ctl(sk, cmd, user, len);
1451 }
1452 return ret;
1453 }
1454 #endif
1455
1456 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1457 {
1458 int ret;
1459
1460 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1461 return -EPERM;
1462
1463 switch (cmd) {
1464 case ARPT_SO_SET_REPLACE:
1465 ret = do_replace(sock_net(sk), user, len);
1466 break;
1467
1468 case ARPT_SO_SET_ADD_COUNTERS:
1469 ret = do_add_counters(sock_net(sk), user, len, 0);
1470 break;
1471
1472 default:
1473 ret = -EINVAL;
1474 }
1475
1476 return ret;
1477 }
1478
1479 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1480 {
1481 int ret;
1482
1483 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1484 return -EPERM;
1485
1486 switch (cmd) {
1487 case ARPT_SO_GET_INFO:
1488 ret = get_info(sock_net(sk), user, len, 0);
1489 break;
1490
1491 case ARPT_SO_GET_ENTRIES:
1492 ret = get_entries(sock_net(sk), user, len);
1493 break;
1494
1495 case ARPT_SO_GET_REVISION_TARGET: {
1496 struct xt_get_revision rev;
1497
1498 if (*len != sizeof(rev)) {
1499 ret = -EINVAL;
1500 break;
1501 }
1502 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1503 ret = -EFAULT;
1504 break;
1505 }
1506 rev.name[sizeof(rev.name)-1] = 0;
1507
1508 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1509 rev.revision, 1, &ret),
1510 "arpt_%s", rev.name);
1511 break;
1512 }
1513
1514 default:
1515 ret = -EINVAL;
1516 }
1517
1518 return ret;
1519 }
1520
1521 static void __arpt_unregister_table(struct xt_table *table)
1522 {
1523 struct xt_table_info *private;
1524 void *loc_cpu_entry;
1525 struct module *table_owner = table->me;
1526 struct arpt_entry *iter;
1527
1528 private = xt_unregister_table(table);
1529
1530 /* Decrease module usage counts and free resources */
1531 loc_cpu_entry = private->entries;
1532 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1533 cleanup_entry(iter);
1534 if (private->number > private->initial_entries)
1535 module_put(table_owner);
1536 xt_free_table_info(private);
1537 }
1538
1539 int arpt_register_table(struct net *net,
1540 const struct xt_table *table,
1541 const struct arpt_replace *repl,
1542 const struct nf_hook_ops *ops,
1543 struct xt_table **res)
1544 {
1545 int ret;
1546 struct xt_table_info *newinfo;
1547 struct xt_table_info bootstrap = {0};
1548 void *loc_cpu_entry;
1549 struct xt_table *new_table;
1550
1551 newinfo = xt_alloc_table_info(repl->size);
1552 if (!newinfo)
1553 return -ENOMEM;
1554
1555 loc_cpu_entry = newinfo->entries;
1556 memcpy(loc_cpu_entry, repl->entries, repl->size);
1557
1558 ret = translate_table(newinfo, loc_cpu_entry, repl);
1559 if (ret != 0)
1560 goto out_free;
1561
1562 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1563 if (IS_ERR(new_table)) {
1564 ret = PTR_ERR(new_table);
1565 goto out_free;
1566 }
1567
1568 /* set res now, will see skbs right after nf_register_net_hooks */
1569 WRITE_ONCE(*res, new_table);
1570
1571 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1572 if (ret != 0) {
1573 __arpt_unregister_table(new_table);
1574 *res = NULL;
1575 }
1576
1577 return ret;
1578
1579 out_free:
1580 xt_free_table_info(newinfo);
1581 return ret;
1582 }
1583
1584 void arpt_unregister_table(struct net *net, struct xt_table *table,
1585 const struct nf_hook_ops *ops)
1586 {
1587 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1588 __arpt_unregister_table(table);
1589 }
1590
1591 /* The built-in targets: standard (NULL) and error. */
1592 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1593 {
1594 .name = XT_STANDARD_TARGET,
1595 .targetsize = sizeof(int),
1596 .family = NFPROTO_ARP,
1597 #ifdef CONFIG_COMPAT
1598 .compatsize = sizeof(compat_int_t),
1599 .compat_from_user = compat_standard_from_user,
1600 .compat_to_user = compat_standard_to_user,
1601 #endif
1602 },
1603 {
1604 .name = XT_ERROR_TARGET,
1605 .target = arpt_error,
1606 .targetsize = XT_FUNCTION_MAXNAMELEN,
1607 .family = NFPROTO_ARP,
1608 },
1609 };
1610
1611 static struct nf_sockopt_ops arpt_sockopts = {
1612 .pf = PF_INET,
1613 .set_optmin = ARPT_BASE_CTL,
1614 .set_optmax = ARPT_SO_SET_MAX+1,
1615 .set = do_arpt_set_ctl,
1616 #ifdef CONFIG_COMPAT
1617 .compat_set = compat_do_arpt_set_ctl,
1618 #endif
1619 .get_optmin = ARPT_BASE_CTL,
1620 .get_optmax = ARPT_SO_GET_MAX+1,
1621 .get = do_arpt_get_ctl,
1622 #ifdef CONFIG_COMPAT
1623 .compat_get = compat_do_arpt_get_ctl,
1624 #endif
1625 .owner = THIS_MODULE,
1626 };
1627
1628 static int __net_init arp_tables_net_init(struct net *net)
1629 {
1630 return xt_proto_init(net, NFPROTO_ARP);
1631 }
1632
1633 static void __net_exit arp_tables_net_exit(struct net *net)
1634 {
1635 xt_proto_fini(net, NFPROTO_ARP);
1636 }
1637
1638 static struct pernet_operations arp_tables_net_ops = {
1639 .init = arp_tables_net_init,
1640 .exit = arp_tables_net_exit,
1641 };
1642
1643 static int __init arp_tables_init(void)
1644 {
1645 int ret;
1646
1647 ret = register_pernet_subsys(&arp_tables_net_ops);
1648 if (ret < 0)
1649 goto err1;
1650
1651 /* No one else will be downing sem now, so we won't sleep */
1652 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1653 if (ret < 0)
1654 goto err2;
1655
1656 /* Register setsockopt */
1657 ret = nf_register_sockopt(&arpt_sockopts);
1658 if (ret < 0)
1659 goto err4;
1660
1661 pr_info("arp_tables: (C) 2002 David S. Miller\n");
1662 return 0;
1663
1664 err4:
1665 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1666 err2:
1667 unregister_pernet_subsys(&arp_tables_net_ops);
1668 err1:
1669 return ret;
1670 }
1671
1672 static void __exit arp_tables_fini(void)
1673 {
1674 nf_unregister_sockopt(&arpt_sockopts);
1675 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1676 unregister_pernet_subsys(&arp_tables_net_ops);
1677 }
1678
1679 EXPORT_SYMBOL(arpt_register_table);
1680 EXPORT_SYMBOL(arpt_unregister_table);
1681 EXPORT_SYMBOL(arpt_do_table);
1682
1683 module_init(arp_tables_init);
1684 module_exit(arp_tables_fini);
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