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