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netfilter: Remove unnecessary cast on void pointer
[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 <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
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 = entry0 + pos;
313
314 if (!(valid_hooks & (1 << hook)))
315 continue;
316
317 /* Set initial back pointer. */
318 e->counters.pcnt = pos;
319
320 for (;;) {
321 const struct xt_standard_target *t
322 = (void *)arpt_get_target_c(e);
323 int visited = e->comefrom & (1 << hook);
324
325 if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
326 return 0;
327
328 e->comefrom
329 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
330
331 /* Unconditional return/END. */
332 if ((unconditional(e) &&
333 (strcmp(t->target.u.user.name,
334 XT_STANDARD_TARGET) == 0) &&
335 t->verdict < 0) || visited) {
336 unsigned int oldpos, size;
337
338 if ((strcmp(t->target.u.user.name,
339 XT_STANDARD_TARGET) == 0) &&
340 t->verdict < -NF_MAX_VERDICT - 1)
341 return 0;
342
343 /* Return: backtrack through the last
344 * big jump.
345 */
346 do {
347 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
348 oldpos = pos;
349 pos = e->counters.pcnt;
350 e->counters.pcnt = 0;
351
352 /* We're at the start. */
353 if (pos == oldpos)
354 goto next;
355
356 e = entry0 + pos;
357 } while (oldpos == pos + e->next_offset);
358
359 /* Move along one */
360 size = e->next_offset;
361 e = entry0 + pos + size;
362 if (pos + size >= newinfo->size)
363 return 0;
364 e->counters.pcnt = pos;
365 pos += size;
366 } else {
367 int newpos = t->verdict;
368
369 if (strcmp(t->target.u.user.name,
370 XT_STANDARD_TARGET) == 0 &&
371 newpos >= 0) {
372 /* This a jump; chase it. */
373 if (!xt_find_jump_offset(offsets, newpos,
374 newinfo->number))
375 return 0;
376 e = entry0 + newpos;
377 } else {
378 /* ... this is a fallthru */
379 newpos = pos + e->next_offset;
380 if (newpos >= newinfo->size)
381 return 0;
382 }
383 e = entry0 + newpos;
384 e->counters.pcnt = pos;
385 pos = newpos;
386 }
387 }
388 next: ;
389 }
390 return 1;
391 }
392
393 static inline int check_target(struct arpt_entry *e, const char *name)
394 {
395 struct xt_entry_target *t = arpt_get_target(e);
396 struct xt_tgchk_param par = {
397 .table = name,
398 .entryinfo = e,
399 .target = t->u.kernel.target,
400 .targinfo = t->data,
401 .hook_mask = e->comefrom,
402 .family = NFPROTO_ARP,
403 };
404
405 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
406 }
407
408 static inline int
409 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
410 struct xt_percpu_counter_alloc_state *alloc_state)
411 {
412 struct xt_entry_target *t;
413 struct xt_target *target;
414 int ret;
415
416 if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
417 return -ENOMEM;
418
419 t = arpt_get_target(e);
420 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
421 t->u.user.revision);
422 if (IS_ERR(target)) {
423 ret = PTR_ERR(target);
424 goto out;
425 }
426 t->u.kernel.target = target;
427
428 ret = check_target(e, name);
429 if (ret)
430 goto err;
431 return 0;
432 err:
433 module_put(t->u.kernel.target->me);
434 out:
435 xt_percpu_counter_free(&e->counters);
436
437 return ret;
438 }
439
440 static bool check_underflow(const struct arpt_entry *e)
441 {
442 const struct xt_entry_target *t;
443 unsigned int verdict;
444
445 if (!unconditional(e))
446 return false;
447 t = arpt_get_target_c(e);
448 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
449 return false;
450 verdict = ((struct xt_standard_target *)t)->verdict;
451 verdict = -verdict - 1;
452 return verdict == NF_DROP || verdict == NF_ACCEPT;
453 }
454
455 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
456 struct xt_table_info *newinfo,
457 const unsigned char *base,
458 const unsigned char *limit,
459 const unsigned int *hook_entries,
460 const unsigned int *underflows,
461 unsigned int valid_hooks)
462 {
463 unsigned int h;
464 int err;
465
466 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
467 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
468 (unsigned char *)e + e->next_offset > limit)
469 return -EINVAL;
470
471 if (e->next_offset
472 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
473 return -EINVAL;
474
475 if (!arp_checkentry(&e->arp))
476 return -EINVAL;
477
478 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
479 e->next_offset);
480 if (err)
481 return err;
482
483 /* Check hooks & underflows */
484 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
485 if (!(valid_hooks & (1 << h)))
486 continue;
487 if ((unsigned char *)e - base == hook_entries[h])
488 newinfo->hook_entry[h] = hook_entries[h];
489 if ((unsigned char *)e - base == underflows[h]) {
490 if (!check_underflow(e))
491 return -EINVAL;
492
493 newinfo->underflow[h] = underflows[h];
494 }
495 }
496
497 /* Clear counters and comefrom */
498 e->counters = ((struct xt_counters) { 0, 0 });
499 e->comefrom = 0;
500 return 0;
501 }
502
503 static inline void cleanup_entry(struct arpt_entry *e)
504 {
505 struct xt_tgdtor_param par;
506 struct xt_entry_target *t;
507
508 t = arpt_get_target(e);
509 par.target = t->u.kernel.target;
510 par.targinfo = t->data;
511 par.family = NFPROTO_ARP;
512 if (par.target->destroy != NULL)
513 par.target->destroy(&par);
514 module_put(par.target->me);
515 xt_percpu_counter_free(&e->counters);
516 }
517
518 /* Checks and translates the user-supplied table segment (held in
519 * newinfo).
520 */
521 static int translate_table(struct xt_table_info *newinfo, void *entry0,
522 const struct arpt_replace *repl)
523 {
524 struct xt_percpu_counter_alloc_state alloc_state = { 0 };
525 struct arpt_entry *iter;
526 unsigned int *offsets;
527 unsigned int i;
528 int ret = 0;
529
530 newinfo->size = repl->size;
531 newinfo->number = repl->num_entries;
532
533 /* Init all hooks to impossible value. */
534 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
535 newinfo->hook_entry[i] = 0xFFFFFFFF;
536 newinfo->underflow[i] = 0xFFFFFFFF;
537 }
538
539 offsets = xt_alloc_entry_offsets(newinfo->number);
540 if (!offsets)
541 return -ENOMEM;
542 i = 0;
543
544 /* Walk through entries, checking offsets. */
545 xt_entry_foreach(iter, entry0, newinfo->size) {
546 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
547 entry0 + repl->size,
548 repl->hook_entry,
549 repl->underflow,
550 repl->valid_hooks);
551 if (ret != 0)
552 goto out_free;
553 if (i < repl->num_entries)
554 offsets[i] = (void *)iter - entry0;
555 ++i;
556 if (strcmp(arpt_get_target(iter)->u.user.name,
557 XT_ERROR_TARGET) == 0)
558 ++newinfo->stacksize;
559 }
560
561 ret = -EINVAL;
562 if (i != repl->num_entries)
563 goto out_free;
564
565 /* Check hooks all assigned */
566 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
567 /* Only hooks which are valid */
568 if (!(repl->valid_hooks & (1 << i)))
569 continue;
570 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
571 goto out_free;
572 if (newinfo->underflow[i] == 0xFFFFFFFF)
573 goto out_free;
574 }
575
576 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
577 ret = -ELOOP;
578 goto out_free;
579 }
580 kvfree(offsets);
581
582 /* Finally, each sanity check must pass */
583 i = 0;
584 xt_entry_foreach(iter, entry0, newinfo->size) {
585 ret = find_check_entry(iter, repl->name, repl->size,
586 &alloc_state);
587 if (ret != 0)
588 break;
589 ++i;
590 }
591
592 if (ret != 0) {
593 xt_entry_foreach(iter, entry0, newinfo->size) {
594 if (i-- == 0)
595 break;
596 cleanup_entry(iter);
597 }
598 return ret;
599 }
600
601 return ret;
602 out_free:
603 kvfree(offsets);
604 return ret;
605 }
606
607 static void get_counters(const struct xt_table_info *t,
608 struct xt_counters counters[])
609 {
610 struct arpt_entry *iter;
611 unsigned int cpu;
612 unsigned int i;
613
614 for_each_possible_cpu(cpu) {
615 seqcount_t *s = &per_cpu(xt_recseq, cpu);
616
617 i = 0;
618 xt_entry_foreach(iter, t->entries, t->size) {
619 struct xt_counters *tmp;
620 u64 bcnt, pcnt;
621 unsigned int start;
622
623 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
624 do {
625 start = read_seqcount_begin(s);
626 bcnt = tmp->bcnt;
627 pcnt = tmp->pcnt;
628 } while (read_seqcount_retry(s, start));
629
630 ADD_COUNTER(counters[i], bcnt, pcnt);
631 ++i;
632 }
633 }
634 }
635
636 static struct xt_counters *alloc_counters(const struct xt_table *table)
637 {
638 unsigned int countersize;
639 struct xt_counters *counters;
640 const struct xt_table_info *private = table->private;
641
642 /* We need atomic snapshot of counters: rest doesn't change
643 * (other than comefrom, which userspace doesn't care
644 * about).
645 */
646 countersize = sizeof(struct xt_counters) * private->number;
647 counters = vzalloc(countersize);
648
649 if (counters == NULL)
650 return ERR_PTR(-ENOMEM);
651
652 get_counters(private, counters);
653
654 return counters;
655 }
656
657 static int copy_entries_to_user(unsigned int total_size,
658 const struct xt_table *table,
659 void __user *userptr)
660 {
661 unsigned int off, num;
662 const struct arpt_entry *e;
663 struct xt_counters *counters;
664 struct xt_table_info *private = table->private;
665 int ret = 0;
666 void *loc_cpu_entry;
667
668 counters = alloc_counters(table);
669 if (IS_ERR(counters))
670 return PTR_ERR(counters);
671
672 loc_cpu_entry = private->entries;
673
674 /* FIXME: use iterator macros --RR */
675 /* ... then go back and fix counters and names */
676 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
677 const struct xt_entry_target *t;
678
679 e = loc_cpu_entry + off;
680 if (copy_to_user(userptr + off, e, sizeof(*e))) {
681 ret = -EFAULT;
682 goto free_counters;
683 }
684 if (copy_to_user(userptr + off
685 + offsetof(struct arpt_entry, counters),
686 &counters[num],
687 sizeof(counters[num])) != 0) {
688 ret = -EFAULT;
689 goto free_counters;
690 }
691
692 t = arpt_get_target_c(e);
693 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
694 ret = -EFAULT;
695 goto free_counters;
696 }
697 }
698
699 free_counters:
700 vfree(counters);
701 return ret;
702 }
703
704 #ifdef CONFIG_COMPAT
705 static void compat_standard_from_user(void *dst, const void *src)
706 {
707 int v = *(compat_int_t *)src;
708
709 if (v > 0)
710 v += xt_compat_calc_jump(NFPROTO_ARP, v);
711 memcpy(dst, &v, sizeof(v));
712 }
713
714 static int compat_standard_to_user(void __user *dst, const void *src)
715 {
716 compat_int_t cv = *(int *)src;
717
718 if (cv > 0)
719 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
720 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
721 }
722
723 static int compat_calc_entry(const struct arpt_entry *e,
724 const struct xt_table_info *info,
725 const void *base, struct xt_table_info *newinfo)
726 {
727 const struct xt_entry_target *t;
728 unsigned int entry_offset;
729 int off, i, ret;
730
731 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
732 entry_offset = (void *)e - base;
733
734 t = arpt_get_target_c(e);
735 off += xt_compat_target_offset(t->u.kernel.target);
736 newinfo->size -= off;
737 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
738 if (ret)
739 return ret;
740
741 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
742 if (info->hook_entry[i] &&
743 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
744 newinfo->hook_entry[i] -= off;
745 if (info->underflow[i] &&
746 (e < (struct arpt_entry *)(base + info->underflow[i])))
747 newinfo->underflow[i] -= off;
748 }
749 return 0;
750 }
751
752 static int compat_table_info(const struct xt_table_info *info,
753 struct xt_table_info *newinfo)
754 {
755 struct arpt_entry *iter;
756 const void *loc_cpu_entry;
757 int ret;
758
759 if (!newinfo || !info)
760 return -EINVAL;
761
762 /* we dont care about newinfo->entries */
763 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
764 newinfo->initial_entries = 0;
765 loc_cpu_entry = info->entries;
766 xt_compat_init_offsets(NFPROTO_ARP, info->number);
767 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
768 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
769 if (ret != 0)
770 return ret;
771 }
772 return 0;
773 }
774 #endif
775
776 static int get_info(struct net *net, void __user *user,
777 const int *len, int compat)
778 {
779 char name[XT_TABLE_MAXNAMELEN];
780 struct xt_table *t;
781 int ret;
782
783 if (*len != sizeof(struct arpt_getinfo))
784 return -EINVAL;
785
786 if (copy_from_user(name, user, sizeof(name)) != 0)
787 return -EFAULT;
788
789 name[XT_TABLE_MAXNAMELEN-1] = '\0';
790 #ifdef CONFIG_COMPAT
791 if (compat)
792 xt_compat_lock(NFPROTO_ARP);
793 #endif
794 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
795 "arptable_%s", name);
796 if (t) {
797 struct arpt_getinfo info;
798 const struct xt_table_info *private = t->private;
799 #ifdef CONFIG_COMPAT
800 struct xt_table_info tmp;
801
802 if (compat) {
803 ret = compat_table_info(private, &tmp);
804 xt_compat_flush_offsets(NFPROTO_ARP);
805 private = &tmp;
806 }
807 #endif
808 memset(&info, 0, sizeof(info));
809 info.valid_hooks = t->valid_hooks;
810 memcpy(info.hook_entry, private->hook_entry,
811 sizeof(info.hook_entry));
812 memcpy(info.underflow, private->underflow,
813 sizeof(info.underflow));
814 info.num_entries = private->number;
815 info.size = private->size;
816 strcpy(info.name, name);
817
818 if (copy_to_user(user, &info, *len) != 0)
819 ret = -EFAULT;
820 else
821 ret = 0;
822 xt_table_unlock(t);
823 module_put(t->me);
824 } else
825 ret = -ENOENT;
826 #ifdef CONFIG_COMPAT
827 if (compat)
828 xt_compat_unlock(NFPROTO_ARP);
829 #endif
830 return ret;
831 }
832
833 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
834 const int *len)
835 {
836 int ret;
837 struct arpt_get_entries get;
838 struct xt_table *t;
839
840 if (*len < sizeof(get))
841 return -EINVAL;
842 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
843 return -EFAULT;
844 if (*len != sizeof(struct arpt_get_entries) + get.size)
845 return -EINVAL;
846
847 get.name[sizeof(get.name) - 1] = '\0';
848
849 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
850 if (t) {
851 const struct xt_table_info *private = t->private;
852
853 if (get.size == private->size)
854 ret = copy_entries_to_user(private->size,
855 t, uptr->entrytable);
856 else
857 ret = -EAGAIN;
858
859 module_put(t->me);
860 xt_table_unlock(t);
861 } else
862 ret = -ENOENT;
863
864 return ret;
865 }
866
867 static int __do_replace(struct net *net, const char *name,
868 unsigned int valid_hooks,
869 struct xt_table_info *newinfo,
870 unsigned int num_counters,
871 void __user *counters_ptr)
872 {
873 int ret;
874 struct xt_table *t;
875 struct xt_table_info *oldinfo;
876 struct xt_counters *counters;
877 void *loc_cpu_old_entry;
878 struct arpt_entry *iter;
879
880 ret = 0;
881 counters = vzalloc(num_counters * sizeof(struct xt_counters));
882 if (!counters) {
883 ret = -ENOMEM;
884 goto out;
885 }
886
887 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
888 "arptable_%s", name);
889 if (!t) {
890 ret = -ENOENT;
891 goto free_newinfo_counters_untrans;
892 }
893
894 /* You lied! */
895 if (valid_hooks != t->valid_hooks) {
896 ret = -EINVAL;
897 goto put_module;
898 }
899
900 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
901 if (!oldinfo)
902 goto put_module;
903
904 /* Update module usage count based on number of rules */
905 if ((oldinfo->number > oldinfo->initial_entries) ||
906 (newinfo->number <= oldinfo->initial_entries))
907 module_put(t->me);
908 if ((oldinfo->number > oldinfo->initial_entries) &&
909 (newinfo->number <= oldinfo->initial_entries))
910 module_put(t->me);
911
912 /* Get the old counters, and synchronize with replace */
913 get_counters(oldinfo, counters);
914
915 /* Decrease module usage counts and free resource */
916 loc_cpu_old_entry = oldinfo->entries;
917 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
918 cleanup_entry(iter);
919
920 xt_free_table_info(oldinfo);
921 if (copy_to_user(counters_ptr, counters,
922 sizeof(struct xt_counters) * num_counters) != 0) {
923 /* Silent error, can't fail, new table is already in place */
924 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
925 }
926 vfree(counters);
927 xt_table_unlock(t);
928 return ret;
929
930 put_module:
931 module_put(t->me);
932 xt_table_unlock(t);
933 free_newinfo_counters_untrans:
934 vfree(counters);
935 out:
936 return ret;
937 }
938
939 static int do_replace(struct net *net, const void __user *user,
940 unsigned int len)
941 {
942 int ret;
943 struct arpt_replace tmp;
944 struct xt_table_info *newinfo;
945 void *loc_cpu_entry;
946 struct arpt_entry *iter;
947
948 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
949 return -EFAULT;
950
951 /* overflow check */
952 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
953 return -ENOMEM;
954 if (tmp.num_counters == 0)
955 return -EINVAL;
956
957 tmp.name[sizeof(tmp.name)-1] = 0;
958
959 newinfo = xt_alloc_table_info(tmp.size);
960 if (!newinfo)
961 return -ENOMEM;
962
963 loc_cpu_entry = newinfo->entries;
964 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
965 tmp.size) != 0) {
966 ret = -EFAULT;
967 goto free_newinfo;
968 }
969
970 ret = translate_table(newinfo, loc_cpu_entry, &tmp);
971 if (ret != 0)
972 goto free_newinfo;
973
974 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
975 tmp.num_counters, tmp.counters);
976 if (ret)
977 goto free_newinfo_untrans;
978 return 0;
979
980 free_newinfo_untrans:
981 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
982 cleanup_entry(iter);
983 free_newinfo:
984 xt_free_table_info(newinfo);
985 return ret;
986 }
987
988 static int do_add_counters(struct net *net, const void __user *user,
989 unsigned int len, int compat)
990 {
991 unsigned int i;
992 struct xt_counters_info tmp;
993 struct xt_counters *paddc;
994 struct xt_table *t;
995 const struct xt_table_info *private;
996 int ret = 0;
997 struct arpt_entry *iter;
998 unsigned int addend;
999
1000 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1001 if (IS_ERR(paddc))
1002 return PTR_ERR(paddc);
1003
1004 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1005 if (!t) {
1006 ret = -ENOENT;
1007 goto free;
1008 }
1009
1010 local_bh_disable();
1011 private = t->private;
1012 if (private->number != tmp.num_counters) {
1013 ret = -EINVAL;
1014 goto unlock_up_free;
1015 }
1016
1017 i = 0;
1018
1019 addend = xt_write_recseq_begin();
1020 xt_entry_foreach(iter, private->entries, private->size) {
1021 struct xt_counters *tmp;
1022
1023 tmp = xt_get_this_cpu_counter(&iter->counters);
1024 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1025 ++i;
1026 }
1027 xt_write_recseq_end(addend);
1028 unlock_up_free:
1029 local_bh_enable();
1030 xt_table_unlock(t);
1031 module_put(t->me);
1032 free:
1033 vfree(paddc);
1034
1035 return ret;
1036 }
1037
1038 #ifdef CONFIG_COMPAT
1039 struct compat_arpt_replace {
1040 char name[XT_TABLE_MAXNAMELEN];
1041 u32 valid_hooks;
1042 u32 num_entries;
1043 u32 size;
1044 u32 hook_entry[NF_ARP_NUMHOOKS];
1045 u32 underflow[NF_ARP_NUMHOOKS];
1046 u32 num_counters;
1047 compat_uptr_t counters;
1048 struct compat_arpt_entry entries[0];
1049 };
1050
1051 static inline void compat_release_entry(struct compat_arpt_entry *e)
1052 {
1053 struct xt_entry_target *t;
1054
1055 t = compat_arpt_get_target(e);
1056 module_put(t->u.kernel.target->me);
1057 }
1058
1059 static int
1060 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1061 struct xt_table_info *newinfo,
1062 unsigned int *size,
1063 const unsigned char *base,
1064 const unsigned char *limit)
1065 {
1066 struct xt_entry_target *t;
1067 struct xt_target *target;
1068 unsigned int entry_offset;
1069 int ret, off;
1070
1071 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1072 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1073 (unsigned char *)e + e->next_offset > limit)
1074 return -EINVAL;
1075
1076 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1077 sizeof(struct compat_xt_entry_target))
1078 return -EINVAL;
1079
1080 if (!arp_checkentry(&e->arp))
1081 return -EINVAL;
1082
1083 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1084 e->next_offset);
1085 if (ret)
1086 return ret;
1087
1088 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1089 entry_offset = (void *)e - (void *)base;
1090
1091 t = compat_arpt_get_target(e);
1092 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1093 t->u.user.revision);
1094 if (IS_ERR(target)) {
1095 ret = PTR_ERR(target);
1096 goto out;
1097 }
1098 t->u.kernel.target = target;
1099
1100 off += xt_compat_target_offset(target);
1101 *size += off;
1102 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1103 if (ret)
1104 goto release_target;
1105
1106 return 0;
1107
1108 release_target:
1109 module_put(t->u.kernel.target->me);
1110 out:
1111 return ret;
1112 }
1113
1114 static void
1115 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1116 unsigned int *size,
1117 struct xt_table_info *newinfo, unsigned char *base)
1118 {
1119 struct xt_entry_target *t;
1120 struct xt_target *target;
1121 struct arpt_entry *de;
1122 unsigned int origsize;
1123 int h;
1124
1125 origsize = *size;
1126 de = *dstptr;
1127 memcpy(de, e, sizeof(struct arpt_entry));
1128 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1129
1130 *dstptr += sizeof(struct arpt_entry);
1131 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1132
1133 de->target_offset = e->target_offset - (origsize - *size);
1134 t = compat_arpt_get_target(e);
1135 target = t->u.kernel.target;
1136 xt_compat_target_from_user(t, dstptr, size);
1137
1138 de->next_offset = e->next_offset - (origsize - *size);
1139 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1140 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1141 newinfo->hook_entry[h] -= origsize - *size;
1142 if ((unsigned char *)de - base < newinfo->underflow[h])
1143 newinfo->underflow[h] -= origsize - *size;
1144 }
1145 }
1146
1147 static int translate_compat_table(struct xt_table_info **pinfo,
1148 void **pentry0,
1149 const struct compat_arpt_replace *compatr)
1150 {
1151 unsigned int i, j;
1152 struct xt_table_info *newinfo, *info;
1153 void *pos, *entry0, *entry1;
1154 struct compat_arpt_entry *iter0;
1155 struct arpt_replace repl;
1156 unsigned int size;
1157 int ret = 0;
1158
1159 info = *pinfo;
1160 entry0 = *pentry0;
1161 size = compatr->size;
1162 info->number = compatr->num_entries;
1163
1164 j = 0;
1165 xt_compat_lock(NFPROTO_ARP);
1166 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1167 /* Walk through entries, checking offsets. */
1168 xt_entry_foreach(iter0, entry0, compatr->size) {
1169 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1170 entry0,
1171 entry0 + compatr->size);
1172 if (ret != 0)
1173 goto out_unlock;
1174 ++j;
1175 }
1176
1177 ret = -EINVAL;
1178 if (j != compatr->num_entries)
1179 goto out_unlock;
1180
1181 ret = -ENOMEM;
1182 newinfo = xt_alloc_table_info(size);
1183 if (!newinfo)
1184 goto out_unlock;
1185
1186 newinfo->number = compatr->num_entries;
1187 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1188 newinfo->hook_entry[i] = compatr->hook_entry[i];
1189 newinfo->underflow[i] = compatr->underflow[i];
1190 }
1191 entry1 = newinfo->entries;
1192 pos = entry1;
1193 size = compatr->size;
1194 xt_entry_foreach(iter0, entry0, compatr->size)
1195 compat_copy_entry_from_user(iter0, &pos, &size,
1196 newinfo, entry1);
1197
1198 /* all module references in entry0 are now gone */
1199
1200 xt_compat_flush_offsets(NFPROTO_ARP);
1201 xt_compat_unlock(NFPROTO_ARP);
1202
1203 memcpy(&repl, compatr, sizeof(*compatr));
1204
1205 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1206 repl.hook_entry[i] = newinfo->hook_entry[i];
1207 repl.underflow[i] = newinfo->underflow[i];
1208 }
1209
1210 repl.num_counters = 0;
1211 repl.counters = NULL;
1212 repl.size = newinfo->size;
1213 ret = translate_table(newinfo, entry1, &repl);
1214 if (ret)
1215 goto free_newinfo;
1216
1217 *pinfo = newinfo;
1218 *pentry0 = entry1;
1219 xt_free_table_info(info);
1220 return 0;
1221
1222 free_newinfo:
1223 xt_free_table_info(newinfo);
1224 return ret;
1225 out_unlock:
1226 xt_compat_flush_offsets(NFPROTO_ARP);
1227 xt_compat_unlock(NFPROTO_ARP);
1228 xt_entry_foreach(iter0, entry0, compatr->size) {
1229 if (j-- == 0)
1230 break;
1231 compat_release_entry(iter0);
1232 }
1233 return ret;
1234 }
1235
1236 static int compat_do_replace(struct net *net, void __user *user,
1237 unsigned int len)
1238 {
1239 int ret;
1240 struct compat_arpt_replace tmp;
1241 struct xt_table_info *newinfo;
1242 void *loc_cpu_entry;
1243 struct arpt_entry *iter;
1244
1245 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1246 return -EFAULT;
1247
1248 /* overflow check */
1249 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1250 return -ENOMEM;
1251 if (tmp.num_counters == 0)
1252 return -EINVAL;
1253
1254 tmp.name[sizeof(tmp.name)-1] = 0;
1255
1256 newinfo = xt_alloc_table_info(tmp.size);
1257 if (!newinfo)
1258 return -ENOMEM;
1259
1260 loc_cpu_entry = newinfo->entries;
1261 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1262 ret = -EFAULT;
1263 goto free_newinfo;
1264 }
1265
1266 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1267 if (ret != 0)
1268 goto free_newinfo;
1269
1270 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1271 tmp.num_counters, compat_ptr(tmp.counters));
1272 if (ret)
1273 goto free_newinfo_untrans;
1274 return 0;
1275
1276 free_newinfo_untrans:
1277 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1278 cleanup_entry(iter);
1279 free_newinfo:
1280 xt_free_table_info(newinfo);
1281 return ret;
1282 }
1283
1284 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1285 unsigned int len)
1286 {
1287 int ret;
1288
1289 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1290 return -EPERM;
1291
1292 switch (cmd) {
1293 case ARPT_SO_SET_REPLACE:
1294 ret = compat_do_replace(sock_net(sk), user, len);
1295 break;
1296
1297 case ARPT_SO_SET_ADD_COUNTERS:
1298 ret = do_add_counters(sock_net(sk), user, len, 1);
1299 break;
1300
1301 default:
1302 ret = -EINVAL;
1303 }
1304
1305 return ret;
1306 }
1307
1308 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1309 compat_uint_t *size,
1310 struct xt_counters *counters,
1311 unsigned int i)
1312 {
1313 struct xt_entry_target *t;
1314 struct compat_arpt_entry __user *ce;
1315 u_int16_t target_offset, next_offset;
1316 compat_uint_t origsize;
1317 int ret;
1318
1319 origsize = *size;
1320 ce = *dstptr;
1321 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1322 copy_to_user(&ce->counters, &counters[i],
1323 sizeof(counters[i])) != 0)
1324 return -EFAULT;
1325
1326 *dstptr += sizeof(struct compat_arpt_entry);
1327 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1328
1329 target_offset = e->target_offset - (origsize - *size);
1330
1331 t = arpt_get_target(e);
1332 ret = xt_compat_target_to_user(t, dstptr, size);
1333 if (ret)
1334 return ret;
1335 next_offset = e->next_offset - (origsize - *size);
1336 if (put_user(target_offset, &ce->target_offset) != 0 ||
1337 put_user(next_offset, &ce->next_offset) != 0)
1338 return -EFAULT;
1339 return 0;
1340 }
1341
1342 static int compat_copy_entries_to_user(unsigned int total_size,
1343 struct xt_table *table,
1344 void __user *userptr)
1345 {
1346 struct xt_counters *counters;
1347 const struct xt_table_info *private = table->private;
1348 void __user *pos;
1349 unsigned int size;
1350 int ret = 0;
1351 unsigned int i = 0;
1352 struct arpt_entry *iter;
1353
1354 counters = alloc_counters(table);
1355 if (IS_ERR(counters))
1356 return PTR_ERR(counters);
1357
1358 pos = userptr;
1359 size = total_size;
1360 xt_entry_foreach(iter, private->entries, total_size) {
1361 ret = compat_copy_entry_to_user(iter, &pos,
1362 &size, counters, i++);
1363 if (ret != 0)
1364 break;
1365 }
1366 vfree(counters);
1367 return ret;
1368 }
1369
1370 struct compat_arpt_get_entries {
1371 char name[XT_TABLE_MAXNAMELEN];
1372 compat_uint_t size;
1373 struct compat_arpt_entry entrytable[0];
1374 };
1375
1376 static int compat_get_entries(struct net *net,
1377 struct compat_arpt_get_entries __user *uptr,
1378 int *len)
1379 {
1380 int ret;
1381 struct compat_arpt_get_entries get;
1382 struct xt_table *t;
1383
1384 if (*len < sizeof(get))
1385 return -EINVAL;
1386 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1387 return -EFAULT;
1388 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1389 return -EINVAL;
1390
1391 get.name[sizeof(get.name) - 1] = '\0';
1392
1393 xt_compat_lock(NFPROTO_ARP);
1394 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1395 if (t) {
1396 const struct xt_table_info *private = t->private;
1397 struct xt_table_info info;
1398
1399 ret = compat_table_info(private, &info);
1400 if (!ret && get.size == info.size) {
1401 ret = compat_copy_entries_to_user(private->size,
1402 t, uptr->entrytable);
1403 } else if (!ret)
1404 ret = -EAGAIN;
1405
1406 xt_compat_flush_offsets(NFPROTO_ARP);
1407 module_put(t->me);
1408 xt_table_unlock(t);
1409 } else
1410 ret = -ENOENT;
1411
1412 xt_compat_unlock(NFPROTO_ARP);
1413 return ret;
1414 }
1415
1416 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1417
1418 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1419 int *len)
1420 {
1421 int ret;
1422
1423 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1424 return -EPERM;
1425
1426 switch (cmd) {
1427 case ARPT_SO_GET_INFO:
1428 ret = get_info(sock_net(sk), user, len, 1);
1429 break;
1430 case ARPT_SO_GET_ENTRIES:
1431 ret = compat_get_entries(sock_net(sk), user, len);
1432 break;
1433 default:
1434 ret = do_arpt_get_ctl(sk, cmd, user, len);
1435 }
1436 return ret;
1437 }
1438 #endif
1439
1440 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1441 {
1442 int ret;
1443
1444 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1445 return -EPERM;
1446
1447 switch (cmd) {
1448 case ARPT_SO_SET_REPLACE:
1449 ret = do_replace(sock_net(sk), user, len);
1450 break;
1451
1452 case ARPT_SO_SET_ADD_COUNTERS:
1453 ret = do_add_counters(sock_net(sk), user, len, 0);
1454 break;
1455
1456 default:
1457 ret = -EINVAL;
1458 }
1459
1460 return ret;
1461 }
1462
1463 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1464 {
1465 int ret;
1466
1467 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1468 return -EPERM;
1469
1470 switch (cmd) {
1471 case ARPT_SO_GET_INFO:
1472 ret = get_info(sock_net(sk), user, len, 0);
1473 break;
1474
1475 case ARPT_SO_GET_ENTRIES:
1476 ret = get_entries(sock_net(sk), user, len);
1477 break;
1478
1479 case ARPT_SO_GET_REVISION_TARGET: {
1480 struct xt_get_revision rev;
1481
1482 if (*len != sizeof(rev)) {
1483 ret = -EINVAL;
1484 break;
1485 }
1486 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1487 ret = -EFAULT;
1488 break;
1489 }
1490 rev.name[sizeof(rev.name)-1] = 0;
1491
1492 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1493 rev.revision, 1, &ret),
1494 "arpt_%s", rev.name);
1495 break;
1496 }
1497
1498 default:
1499 ret = -EINVAL;
1500 }
1501
1502 return ret;
1503 }
1504
1505 static void __arpt_unregister_table(struct xt_table *table)
1506 {
1507 struct xt_table_info *private;
1508 void *loc_cpu_entry;
1509 struct module *table_owner = table->me;
1510 struct arpt_entry *iter;
1511
1512 private = xt_unregister_table(table);
1513
1514 /* Decrease module usage counts and free resources */
1515 loc_cpu_entry = private->entries;
1516 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1517 cleanup_entry(iter);
1518 if (private->number > private->initial_entries)
1519 module_put(table_owner);
1520 xt_free_table_info(private);
1521 }
1522
1523 int arpt_register_table(struct net *net,
1524 const struct xt_table *table,
1525 const struct arpt_replace *repl,
1526 const struct nf_hook_ops *ops,
1527 struct xt_table **res)
1528 {
1529 int ret;
1530 struct xt_table_info *newinfo;
1531 struct xt_table_info bootstrap = {0};
1532 void *loc_cpu_entry;
1533 struct xt_table *new_table;
1534
1535 newinfo = xt_alloc_table_info(repl->size);
1536 if (!newinfo)
1537 return -ENOMEM;
1538
1539 loc_cpu_entry = newinfo->entries;
1540 memcpy(loc_cpu_entry, repl->entries, repl->size);
1541
1542 ret = translate_table(newinfo, loc_cpu_entry, repl);
1543 if (ret != 0)
1544 goto out_free;
1545
1546 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1547 if (IS_ERR(new_table)) {
1548 ret = PTR_ERR(new_table);
1549 goto out_free;
1550 }
1551
1552 /* set res now, will see skbs right after nf_register_net_hooks */
1553 WRITE_ONCE(*res, new_table);
1554
1555 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1556 if (ret != 0) {
1557 __arpt_unregister_table(new_table);
1558 *res = NULL;
1559 }
1560
1561 return ret;
1562
1563 out_free:
1564 xt_free_table_info(newinfo);
1565 return ret;
1566 }
1567
1568 void arpt_unregister_table(struct net *net, struct xt_table *table,
1569 const struct nf_hook_ops *ops)
1570 {
1571 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1572 __arpt_unregister_table(table);
1573 }
1574
1575 /* The built-in targets: standard (NULL) and error. */
1576 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1577 {
1578 .name = XT_STANDARD_TARGET,
1579 .targetsize = sizeof(int),
1580 .family = NFPROTO_ARP,
1581 #ifdef CONFIG_COMPAT
1582 .compatsize = sizeof(compat_int_t),
1583 .compat_from_user = compat_standard_from_user,
1584 .compat_to_user = compat_standard_to_user,
1585 #endif
1586 },
1587 {
1588 .name = XT_ERROR_TARGET,
1589 .target = arpt_error,
1590 .targetsize = XT_FUNCTION_MAXNAMELEN,
1591 .family = NFPROTO_ARP,
1592 },
1593 };
1594
1595 static struct nf_sockopt_ops arpt_sockopts = {
1596 .pf = PF_INET,
1597 .set_optmin = ARPT_BASE_CTL,
1598 .set_optmax = ARPT_SO_SET_MAX+1,
1599 .set = do_arpt_set_ctl,
1600 #ifdef CONFIG_COMPAT
1601 .compat_set = compat_do_arpt_set_ctl,
1602 #endif
1603 .get_optmin = ARPT_BASE_CTL,
1604 .get_optmax = ARPT_SO_GET_MAX+1,
1605 .get = do_arpt_get_ctl,
1606 #ifdef CONFIG_COMPAT
1607 .compat_get = compat_do_arpt_get_ctl,
1608 #endif
1609 .owner = THIS_MODULE,
1610 };
1611
1612 static int __net_init arp_tables_net_init(struct net *net)
1613 {
1614 return xt_proto_init(net, NFPROTO_ARP);
1615 }
1616
1617 static void __net_exit arp_tables_net_exit(struct net *net)
1618 {
1619 xt_proto_fini(net, NFPROTO_ARP);
1620 }
1621
1622 static struct pernet_operations arp_tables_net_ops = {
1623 .init = arp_tables_net_init,
1624 .exit = arp_tables_net_exit,
1625 };
1626
1627 static int __init arp_tables_init(void)
1628 {
1629 int ret;
1630
1631 ret = register_pernet_subsys(&arp_tables_net_ops);
1632 if (ret < 0)
1633 goto err1;
1634
1635 /* No one else will be downing sem now, so we won't sleep */
1636 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1637 if (ret < 0)
1638 goto err2;
1639
1640 /* Register setsockopt */
1641 ret = nf_register_sockopt(&arpt_sockopts);
1642 if (ret < 0)
1643 goto err4;
1644
1645 pr_info("arp_tables: (C) 2002 David S. Miller\n");
1646 return 0;
1647
1648 err4:
1649 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1650 err2:
1651 unregister_pernet_subsys(&arp_tables_net_ops);
1652 err1:
1653 return ret;
1654 }
1655
1656 static void __exit arp_tables_fini(void)
1657 {
1658 nf_unregister_sockopt(&arpt_sockopts);
1659 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1660 unregister_pernet_subsys(&arp_tables_net_ops);
1661 }
1662
1663 EXPORT_SYMBOL(arpt_register_table);
1664 EXPORT_SYMBOL(arpt_unregister_table);
1665 EXPORT_SYMBOL(arpt_do_table);
1666
1667 module_init(arp_tables_init);
1668 module_exit(arp_tables_fini);
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