1 // SPDX-License-Identifier: GPL-2.0-only
3 * Packet matching code for ARP packets.
5 * Based heavily, if not almost entirely, upon ip_tables.c framework.
7 * Some ARP specific bits are:
9 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
10 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
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>
28 #include <linux/uaccess.h>
30 #include <linux/netfilter/x_tables.h>
31 #include <linux/netfilter_arp/arp_tables.h>
32 #include "../../netfilter/xt_repldata.h"
34 MODULE_LICENSE("GPL");
35 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
36 MODULE_DESCRIPTION("arptables core");
38 void *arpt_alloc_initial_table(const struct xt_table *info)
40 return xt_alloc_initial_table(arpt, ARPT);
42 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
44 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
45 const char *hdr_addr, int len)
49 if (len > ARPT_DEV_ADDR_LEN_MAX)
50 len = ARPT_DEV_ADDR_LEN_MAX;
53 for (i = 0; i < len; i++)
54 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
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.
64 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
66 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
67 unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
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;
75 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
76 ret |= (a[i] ^ b[i]) & mask[i];
81 /* Returns whether packet matches rule or not. */
82 static inline int arp_packet_match(const struct arphdr *arphdr,
83 struct net_device *dev,
86 const struct arpt_arp *arpinfo)
88 const char *arpptr = (char *)(arphdr + 1);
89 const char *src_devaddr, *tgt_devaddr;
90 __be32 src_ipaddr, tgt_ipaddr;
93 if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
94 (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
97 if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
98 (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
101 if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
102 (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
105 if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
106 (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
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));
117 if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
118 arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
120 NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
121 arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
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))
131 /* Look for ifname matches. */
132 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
134 if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
137 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
139 if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
145 static inline int arp_checkentry(const struct arpt_arp *arp)
147 if (arp->flags & ~ARPT_F_MASK)
149 if (arp->invflags & ~ARPT_INV_MASK)
156 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
158 net_err_ratelimited("arp_tables: error: '%s'\n",
159 (const char *)par->targinfo);
164 static inline const struct xt_entry_target *
165 arpt_get_target_c(const struct arpt_entry *e)
167 return arpt_get_target((struct arpt_entry *)e);
170 static inline struct arpt_entry *
171 get_entry(const void *base, unsigned int offset)
173 return (struct arpt_entry *)(base + offset);
177 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
179 return (void *)entry + entry->next_offset;
182 unsigned int arpt_do_table(void *priv,
184 const struct nf_hook_state *state)
186 const struct xt_table *table = priv;
187 unsigned int hook = state->hook;
188 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
189 unsigned int verdict = NF_DROP;
190 const struct arphdr *arp;
191 struct arpt_entry *e, **jumpstack;
192 const char *indev, *outdev;
193 const void *table_base;
194 unsigned int cpu, stackidx = 0;
195 const struct xt_table_info *private;
196 struct xt_action_param acpar;
199 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
202 indev = state->in ? state->in->name : nulldevname;
203 outdev = state->out ? state->out->name : nulldevname;
206 addend = xt_write_recseq_begin();
207 private = READ_ONCE(table->private); /* Address dependency. */
208 cpu = smp_processor_id();
209 table_base = private->entries;
210 jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
212 /* No TEE support for arptables, so no need to switch to alternate
213 * stack. All targets that reenter must return absolute verdicts.
215 e = get_entry(table_base, private->hook_entry[hook]);
218 acpar.hotdrop = false;
222 const struct xt_entry_target *t;
223 struct xt_counters *counter;
225 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
226 e = arpt_next_entry(e);
230 counter = xt_get_this_cpu_counter(&e->counters);
231 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
233 t = arpt_get_target_c(e);
235 /* Standard target? */
236 if (!t->u.kernel.target->target) {
239 v = ((struct xt_standard_target *)t)->verdict;
241 /* Pop from stack? */
242 if (v != XT_RETURN) {
243 verdict = (unsigned int)(-v) - 1;
247 e = get_entry(table_base,
248 private->underflow[hook]);
250 e = jumpstack[--stackidx];
251 e = arpt_next_entry(e);
256 != arpt_next_entry(e)) {
257 if (unlikely(stackidx >= private->stacksize)) {
261 jumpstack[stackidx++] = e;
264 e = get_entry(table_base, v);
268 acpar.target = t->u.kernel.target;
269 acpar.targinfo = t->data;
270 verdict = t->u.kernel.target->target(skb, &acpar);
272 if (verdict == XT_CONTINUE) {
273 /* Target might have changed stuff. */
275 e = arpt_next_entry(e);
280 } while (!acpar.hotdrop);
281 xt_write_recseq_end(addend);
290 /* All zeroes == unconditional rule. */
291 static inline bool unconditional(const struct arpt_entry *e)
293 static const struct arpt_arp uncond;
295 return e->target_offset == sizeof(struct arpt_entry) &&
296 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
299 /* Figures out from what hook each rule can be called: returns 0 if
300 * there are loops. Puts hook bitmask in comefrom.
302 static int mark_source_chains(const struct xt_table_info *newinfo,
303 unsigned int valid_hooks, void *entry0,
304 unsigned int *offsets)
308 /* No recursion; use packet counter to save back ptrs (reset
309 * to 0 as we leave), and comefrom to save source hook bitmask.
311 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
312 unsigned int pos = newinfo->hook_entry[hook];
313 struct arpt_entry *e = entry0 + pos;
315 if (!(valid_hooks & (1 << hook)))
318 /* Set initial back pointer. */
319 e->counters.pcnt = pos;
322 const struct xt_standard_target *t
323 = (void *)arpt_get_target_c(e);
324 int visited = e->comefrom & (1 << hook);
326 if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
330 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
332 /* Unconditional return/END. */
333 if ((unconditional(e) &&
334 (strcmp(t->target.u.user.name,
335 XT_STANDARD_TARGET) == 0) &&
336 t->verdict < 0) || visited) {
337 unsigned int oldpos, size;
339 /* Return: backtrack through the last
343 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
345 pos = e->counters.pcnt;
346 e->counters.pcnt = 0;
348 /* We're at the start. */
353 } while (oldpos == pos + e->next_offset);
356 size = e->next_offset;
357 e = entry0 + pos + size;
358 if (pos + size >= newinfo->size)
360 e->counters.pcnt = pos;
363 int newpos = t->verdict;
365 if (strcmp(t->target.u.user.name,
366 XT_STANDARD_TARGET) == 0 &&
368 /* This a jump; chase it. */
369 if (!xt_find_jump_offset(offsets, newpos,
373 /* ... this is a fallthru */
374 newpos = pos + e->next_offset;
375 if (newpos >= newinfo->size)
379 e->counters.pcnt = pos;
388 static int check_target(struct arpt_entry *e, struct net *net, const char *name)
390 struct xt_entry_target *t = arpt_get_target(e);
391 struct xt_tgchk_param par = {
395 .target = t->u.kernel.target,
397 .hook_mask = e->comefrom,
398 .family = NFPROTO_ARP,
401 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
405 find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
407 struct xt_percpu_counter_alloc_state *alloc_state)
409 struct xt_entry_target *t;
410 struct xt_target *target;
413 if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
416 t = arpt_get_target(e);
417 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
419 if (IS_ERR(target)) {
420 ret = PTR_ERR(target);
423 t->u.kernel.target = target;
425 ret = check_target(e, net, name);
430 module_put(t->u.kernel.target->me);
432 xt_percpu_counter_free(&e->counters);
437 static bool check_underflow(const struct arpt_entry *e)
439 const struct xt_entry_target *t;
440 unsigned int verdict;
442 if (!unconditional(e))
444 t = arpt_get_target_c(e);
445 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
447 verdict = ((struct xt_standard_target *)t)->verdict;
448 verdict = -verdict - 1;
449 return verdict == NF_DROP || verdict == NF_ACCEPT;
452 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
453 struct xt_table_info *newinfo,
454 const unsigned char *base,
455 const unsigned char *limit,
456 const unsigned int *hook_entries,
457 const unsigned int *underflows,
458 unsigned int valid_hooks)
463 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
464 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
465 (unsigned char *)e + e->next_offset > limit)
469 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
472 if (!arp_checkentry(&e->arp))
475 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
480 /* Check hooks & underflows */
481 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
482 if (!(valid_hooks & (1 << h)))
484 if ((unsigned char *)e - base == hook_entries[h])
485 newinfo->hook_entry[h] = hook_entries[h];
486 if ((unsigned char *)e - base == underflows[h]) {
487 if (!check_underflow(e))
490 newinfo->underflow[h] = underflows[h];
494 /* Clear counters and comefrom */
495 e->counters = ((struct xt_counters) { 0, 0 });
500 static void cleanup_entry(struct arpt_entry *e, struct net *net)
502 struct xt_tgdtor_param par;
503 struct xt_entry_target *t;
505 t = arpt_get_target(e);
507 par.target = t->u.kernel.target;
508 par.targinfo = t->data;
509 par.family = NFPROTO_ARP;
510 if (par.target->destroy != NULL)
511 par.target->destroy(&par);
512 module_put(par.target->me);
513 xt_percpu_counter_free(&e->counters);
516 /* Checks and translates the user-supplied table segment (held in
519 static int translate_table(struct net *net,
520 struct xt_table_info *newinfo,
522 const struct arpt_replace *repl)
524 struct xt_percpu_counter_alloc_state alloc_state = { 0 };
525 struct arpt_entry *iter;
526 unsigned int *offsets;
530 newinfo->size = repl->size;
531 newinfo->number = repl->num_entries;
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;
539 offsets = xt_alloc_entry_offsets(newinfo->number);
544 /* Walk through entries, checking offsets. */
545 xt_entry_foreach(iter, entry0, newinfo->size) {
546 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
553 if (i < repl->num_entries)
554 offsets[i] = (void *)iter - entry0;
556 if (strcmp(arpt_get_target(iter)->u.user.name,
557 XT_ERROR_TARGET) == 0)
558 ++newinfo->stacksize;
562 if (i != repl->num_entries)
565 ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
569 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
575 /* Finally, each sanity check must pass */
577 xt_entry_foreach(iter, entry0, newinfo->size) {
578 ret = find_check_entry(iter, net, repl->name, repl->size,
586 xt_entry_foreach(iter, entry0, newinfo->size) {
589 cleanup_entry(iter, net);
600 static void get_counters(const struct xt_table_info *t,
601 struct xt_counters counters[])
603 struct arpt_entry *iter;
607 for_each_possible_cpu(cpu) {
608 seqcount_t *s = &per_cpu(xt_recseq, cpu);
611 xt_entry_foreach(iter, t->entries, t->size) {
612 struct xt_counters *tmp;
616 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
618 start = read_seqcount_begin(s);
621 } while (read_seqcount_retry(s, start));
623 ADD_COUNTER(counters[i], bcnt, pcnt);
630 static void get_old_counters(const struct xt_table_info *t,
631 struct xt_counters counters[])
633 struct arpt_entry *iter;
636 for_each_possible_cpu(cpu) {
638 xt_entry_foreach(iter, t->entries, t->size) {
639 struct xt_counters *tmp;
641 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
642 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
649 static struct xt_counters *alloc_counters(const struct xt_table *table)
651 unsigned int countersize;
652 struct xt_counters *counters;
653 const struct xt_table_info *private = table->private;
655 /* We need atomic snapshot of counters: rest doesn't change
656 * (other than comefrom, which userspace doesn't care
659 countersize = sizeof(struct xt_counters) * private->number;
660 counters = vzalloc(countersize);
662 if (counters == NULL)
663 return ERR_PTR(-ENOMEM);
665 get_counters(private, counters);
670 static int copy_entries_to_user(unsigned int total_size,
671 const struct xt_table *table,
672 void __user *userptr)
674 unsigned int off, num;
675 const struct arpt_entry *e;
676 struct xt_counters *counters;
677 struct xt_table_info *private = table->private;
681 counters = alloc_counters(table);
682 if (IS_ERR(counters))
683 return PTR_ERR(counters);
685 loc_cpu_entry = private->entries;
687 /* FIXME: use iterator macros --RR */
688 /* ... then go back and fix counters and names */
689 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
690 const struct xt_entry_target *t;
692 e = loc_cpu_entry + off;
693 if (copy_to_user(userptr + off, e, sizeof(*e))) {
697 if (copy_to_user(userptr + off
698 + offsetof(struct arpt_entry, counters),
700 sizeof(counters[num])) != 0) {
705 t = arpt_get_target_c(e);
706 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
717 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
718 static void compat_standard_from_user(void *dst, const void *src)
720 int v = *(compat_int_t *)src;
723 v += xt_compat_calc_jump(NFPROTO_ARP, v);
724 memcpy(dst, &v, sizeof(v));
727 static int compat_standard_to_user(void __user *dst, const void *src)
729 compat_int_t cv = *(int *)src;
732 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
733 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
736 static int compat_calc_entry(const struct arpt_entry *e,
737 const struct xt_table_info *info,
738 const void *base, struct xt_table_info *newinfo)
740 const struct xt_entry_target *t;
741 unsigned int entry_offset;
744 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
745 entry_offset = (void *)e - base;
747 t = arpt_get_target_c(e);
748 off += xt_compat_target_offset(t->u.kernel.target);
749 newinfo->size -= off;
750 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
754 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
755 if (info->hook_entry[i] &&
756 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
757 newinfo->hook_entry[i] -= off;
758 if (info->underflow[i] &&
759 (e < (struct arpt_entry *)(base + info->underflow[i])))
760 newinfo->underflow[i] -= off;
765 static int compat_table_info(const struct xt_table_info *info,
766 struct xt_table_info *newinfo)
768 struct arpt_entry *iter;
769 const void *loc_cpu_entry;
772 if (!newinfo || !info)
775 /* we dont care about newinfo->entries */
776 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
777 newinfo->initial_entries = 0;
778 loc_cpu_entry = info->entries;
779 ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
782 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
783 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
791 static int get_info(struct net *net, void __user *user, const int *len)
793 char name[XT_TABLE_MAXNAMELEN];
797 if (*len != sizeof(struct arpt_getinfo))
800 if (copy_from_user(name, user, sizeof(name)) != 0)
803 name[XT_TABLE_MAXNAMELEN-1] = '\0';
804 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
805 if (in_compat_syscall())
806 xt_compat_lock(NFPROTO_ARP);
808 t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
810 struct arpt_getinfo info;
811 const struct xt_table_info *private = t->private;
812 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
813 struct xt_table_info tmp;
815 if (in_compat_syscall()) {
816 ret = compat_table_info(private, &tmp);
817 xt_compat_flush_offsets(NFPROTO_ARP);
821 memset(&info, 0, sizeof(info));
822 info.valid_hooks = t->valid_hooks;
823 memcpy(info.hook_entry, private->hook_entry,
824 sizeof(info.hook_entry));
825 memcpy(info.underflow, private->underflow,
826 sizeof(info.underflow));
827 info.num_entries = private->number;
828 info.size = private->size;
829 strscpy(info.name, name);
831 if (copy_to_user(user, &info, *len) != 0)
839 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
840 if (in_compat_syscall())
841 xt_compat_unlock(NFPROTO_ARP);
846 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
850 struct arpt_get_entries get;
853 if (*len < sizeof(get))
855 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
857 if (*len != sizeof(struct arpt_get_entries) + get.size)
860 get.name[sizeof(get.name) - 1] = '\0';
862 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
864 const struct xt_table_info *private = t->private;
866 if (get.size == private->size)
867 ret = copy_entries_to_user(private->size,
868 t, uptr->entrytable);
880 static int __do_replace(struct net *net, const char *name,
881 unsigned int valid_hooks,
882 struct xt_table_info *newinfo,
883 unsigned int num_counters,
884 void __user *counters_ptr)
888 struct xt_table_info *oldinfo;
889 struct xt_counters *counters;
890 void *loc_cpu_old_entry;
891 struct arpt_entry *iter;
894 counters = xt_counters_alloc(num_counters);
900 t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
903 goto free_newinfo_counters_untrans;
907 if (valid_hooks != t->valid_hooks) {
912 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
916 /* Update module usage count based on number of rules */
917 if ((oldinfo->number > oldinfo->initial_entries) ||
918 (newinfo->number <= oldinfo->initial_entries))
920 if ((oldinfo->number > oldinfo->initial_entries) &&
921 (newinfo->number <= oldinfo->initial_entries))
926 get_old_counters(oldinfo, counters);
928 /* Decrease module usage counts and free resource */
929 loc_cpu_old_entry = oldinfo->entries;
930 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
931 cleanup_entry(iter, net);
933 xt_free_table_info(oldinfo);
934 if (copy_to_user(counters_ptr, counters,
935 sizeof(struct xt_counters) * num_counters) != 0) {
936 /* Silent error, can't fail, new table is already in place */
937 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
945 free_newinfo_counters_untrans:
951 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
954 struct arpt_replace tmp;
955 struct xt_table_info *newinfo;
957 struct arpt_entry *iter;
959 if (len < sizeof(tmp))
961 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
965 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
967 if (tmp.num_counters == 0)
969 if ((u64)len < (u64)tmp.size + sizeof(tmp))
972 tmp.name[sizeof(tmp.name)-1] = 0;
974 newinfo = xt_alloc_table_info(tmp.size);
978 loc_cpu_entry = newinfo->entries;
979 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
985 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
989 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
990 tmp.num_counters, tmp.counters);
992 goto free_newinfo_untrans;
995 free_newinfo_untrans:
996 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
997 cleanup_entry(iter, net);
999 xt_free_table_info(newinfo);
1003 static int do_add_counters(struct net *net, sockptr_t arg, unsigned int len)
1006 struct xt_counters_info tmp;
1007 struct xt_counters *paddc;
1009 const struct xt_table_info *private;
1011 struct arpt_entry *iter;
1012 unsigned int addend;
1014 paddc = xt_copy_counters(arg, len, &tmp);
1016 return PTR_ERR(paddc);
1018 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1025 private = t->private;
1026 if (private->number != tmp.num_counters) {
1028 goto unlock_up_free;
1033 addend = xt_write_recseq_begin();
1034 xt_entry_foreach(iter, private->entries, private->size) {
1035 struct xt_counters *tmp;
1037 tmp = xt_get_this_cpu_counter(&iter->counters);
1038 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1041 xt_write_recseq_end(addend);
1052 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1053 struct compat_arpt_replace {
1054 char name[XT_TABLE_MAXNAMELEN];
1058 u32 hook_entry[NF_ARP_NUMHOOKS];
1059 u32 underflow[NF_ARP_NUMHOOKS];
1061 compat_uptr_t counters;
1062 struct compat_arpt_entry entries[];
1065 static inline void compat_release_entry(struct compat_arpt_entry *e)
1067 struct xt_entry_target *t;
1069 t = compat_arpt_get_target(e);
1070 module_put(t->u.kernel.target->me);
1074 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1075 struct xt_table_info *newinfo,
1077 const unsigned char *base,
1078 const unsigned char *limit)
1080 struct xt_entry_target *t;
1081 struct xt_target *target;
1082 unsigned int entry_offset;
1085 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1086 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1087 (unsigned char *)e + e->next_offset > limit)
1090 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1091 sizeof(struct compat_xt_entry_target))
1094 if (!arp_checkentry(&e->arp))
1097 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1102 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1103 entry_offset = (void *)e - (void *)base;
1105 t = compat_arpt_get_target(e);
1106 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1107 t->u.user.revision);
1108 if (IS_ERR(target)) {
1109 ret = PTR_ERR(target);
1112 t->u.kernel.target = target;
1114 off += xt_compat_target_offset(target);
1116 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1118 goto release_target;
1123 module_put(t->u.kernel.target->me);
1129 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1131 struct xt_table_info *newinfo, unsigned char *base)
1133 struct xt_entry_target *t;
1134 struct arpt_entry *de;
1135 unsigned int origsize;
1140 memcpy(de, e, sizeof(struct arpt_entry));
1141 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1143 *dstptr += sizeof(struct arpt_entry);
1144 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1146 de->target_offset = e->target_offset - (origsize - *size);
1147 t = compat_arpt_get_target(e);
1148 xt_compat_target_from_user(t, dstptr, size);
1150 de->next_offset = e->next_offset - (origsize - *size);
1151 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1152 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1153 newinfo->hook_entry[h] -= origsize - *size;
1154 if ((unsigned char *)de - base < newinfo->underflow[h])
1155 newinfo->underflow[h] -= origsize - *size;
1159 static int translate_compat_table(struct net *net,
1160 struct xt_table_info **pinfo,
1162 const struct compat_arpt_replace *compatr)
1165 struct xt_table_info *newinfo, *info;
1166 void *pos, *entry0, *entry1;
1167 struct compat_arpt_entry *iter0;
1168 struct arpt_replace repl;
1174 size = compatr->size;
1175 info->number = compatr->num_entries;
1178 xt_compat_lock(NFPROTO_ARP);
1179 ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1182 /* Walk through entries, checking offsets. */
1183 xt_entry_foreach(iter0, entry0, compatr->size) {
1184 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1186 entry0 + compatr->size);
1193 if (j != compatr->num_entries)
1197 newinfo = xt_alloc_table_info(size);
1201 memset(newinfo->entries, 0, size);
1203 newinfo->number = compatr->num_entries;
1204 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1205 newinfo->hook_entry[i] = compatr->hook_entry[i];
1206 newinfo->underflow[i] = compatr->underflow[i];
1208 entry1 = newinfo->entries;
1210 size = compatr->size;
1211 xt_entry_foreach(iter0, entry0, compatr->size)
1212 compat_copy_entry_from_user(iter0, &pos, &size,
1215 /* all module references in entry0 are now gone */
1217 xt_compat_flush_offsets(NFPROTO_ARP);
1218 xt_compat_unlock(NFPROTO_ARP);
1220 memcpy(&repl, compatr, sizeof(*compatr));
1222 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1223 repl.hook_entry[i] = newinfo->hook_entry[i];
1224 repl.underflow[i] = newinfo->underflow[i];
1227 repl.num_counters = 0;
1228 repl.counters = NULL;
1229 repl.size = newinfo->size;
1230 ret = translate_table(net, newinfo, entry1, &repl);
1236 xt_free_table_info(info);
1240 xt_free_table_info(newinfo);
1243 xt_compat_flush_offsets(NFPROTO_ARP);
1244 xt_compat_unlock(NFPROTO_ARP);
1245 xt_entry_foreach(iter0, entry0, compatr->size) {
1248 compat_release_entry(iter0);
1253 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
1256 struct compat_arpt_replace tmp;
1257 struct xt_table_info *newinfo;
1258 void *loc_cpu_entry;
1259 struct arpt_entry *iter;
1261 if (len < sizeof(tmp))
1263 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1266 /* overflow check */
1267 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1269 if (tmp.num_counters == 0)
1271 if ((u64)len < (u64)tmp.size + sizeof(tmp))
1274 tmp.name[sizeof(tmp.name)-1] = 0;
1276 newinfo = xt_alloc_table_info(tmp.size);
1280 loc_cpu_entry = newinfo->entries;
1281 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
1287 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1291 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1292 tmp.num_counters, compat_ptr(tmp.counters));
1294 goto free_newinfo_untrans;
1297 free_newinfo_untrans:
1298 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1299 cleanup_entry(iter, net);
1301 xt_free_table_info(newinfo);
1305 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1306 compat_uint_t *size,
1307 struct xt_counters *counters,
1310 struct xt_entry_target *t;
1311 struct compat_arpt_entry __user *ce;
1312 u_int16_t target_offset, next_offset;
1313 compat_uint_t origsize;
1318 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1319 copy_to_user(&ce->counters, &counters[i],
1320 sizeof(counters[i])) != 0)
1323 *dstptr += sizeof(struct compat_arpt_entry);
1324 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1326 target_offset = e->target_offset - (origsize - *size);
1328 t = arpt_get_target(e);
1329 ret = xt_compat_target_to_user(t, dstptr, size);
1332 next_offset = e->next_offset - (origsize - *size);
1333 if (put_user(target_offset, &ce->target_offset) != 0 ||
1334 put_user(next_offset, &ce->next_offset) != 0)
1339 static int compat_copy_entries_to_user(unsigned int total_size,
1340 struct xt_table *table,
1341 void __user *userptr)
1343 struct xt_counters *counters;
1344 const struct xt_table_info *private = table->private;
1349 struct arpt_entry *iter;
1351 counters = alloc_counters(table);
1352 if (IS_ERR(counters))
1353 return PTR_ERR(counters);
1357 xt_entry_foreach(iter, private->entries, total_size) {
1358 ret = compat_copy_entry_to_user(iter, &pos,
1359 &size, counters, i++);
1367 struct compat_arpt_get_entries {
1368 char name[XT_TABLE_MAXNAMELEN];
1370 struct compat_arpt_entry entrytable[];
1373 static int compat_get_entries(struct net *net,
1374 struct compat_arpt_get_entries __user *uptr,
1378 struct compat_arpt_get_entries get;
1381 if (*len < sizeof(get))
1383 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1385 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1388 get.name[sizeof(get.name) - 1] = '\0';
1390 xt_compat_lock(NFPROTO_ARP);
1391 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1393 const struct xt_table_info *private = t->private;
1394 struct xt_table_info info;
1396 ret = compat_table_info(private, &info);
1397 if (!ret && get.size == info.size) {
1398 ret = compat_copy_entries_to_user(private->size,
1399 t, uptr->entrytable);
1403 xt_compat_flush_offsets(NFPROTO_ARP);
1409 xt_compat_unlock(NFPROTO_ARP);
1414 static int do_arpt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
1419 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1423 case ARPT_SO_SET_REPLACE:
1424 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1425 if (in_compat_syscall())
1426 ret = compat_do_replace(sock_net(sk), arg, len);
1429 ret = do_replace(sock_net(sk), arg, len);
1432 case ARPT_SO_SET_ADD_COUNTERS:
1433 ret = do_add_counters(sock_net(sk), arg, len);
1443 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1447 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1451 case ARPT_SO_GET_INFO:
1452 ret = get_info(sock_net(sk), user, len);
1455 case ARPT_SO_GET_ENTRIES:
1456 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1457 if (in_compat_syscall())
1458 ret = compat_get_entries(sock_net(sk), user, len);
1461 ret = get_entries(sock_net(sk), user, len);
1464 case ARPT_SO_GET_REVISION_TARGET: {
1465 struct xt_get_revision rev;
1467 if (*len != sizeof(rev)) {
1471 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1475 rev.name[sizeof(rev.name)-1] = 0;
1477 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1478 rev.revision, 1, &ret),
1479 "arpt_%s", rev.name);
1490 static void __arpt_unregister_table(struct net *net, struct xt_table *table)
1492 struct xt_table_info *private;
1493 void *loc_cpu_entry;
1494 struct module *table_owner = table->me;
1495 struct arpt_entry *iter;
1497 private = xt_unregister_table(table);
1499 /* Decrease module usage counts and free resources */
1500 loc_cpu_entry = private->entries;
1501 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1502 cleanup_entry(iter, net);
1503 if (private->number > private->initial_entries)
1504 module_put(table_owner);
1505 xt_free_table_info(private);
1508 int arpt_register_table(struct net *net,
1509 const struct xt_table *table,
1510 const struct arpt_replace *repl,
1511 const struct nf_hook_ops *template_ops)
1513 struct nf_hook_ops *ops;
1514 unsigned int num_ops;
1516 struct xt_table_info *newinfo;
1517 struct xt_table_info bootstrap = {0};
1518 void *loc_cpu_entry;
1519 struct xt_table *new_table;
1521 newinfo = xt_alloc_table_info(repl->size);
1525 loc_cpu_entry = newinfo->entries;
1526 memcpy(loc_cpu_entry, repl->entries, repl->size);
1528 ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1530 xt_free_table_info(newinfo);
1534 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1535 if (IS_ERR(new_table)) {
1536 struct arpt_entry *iter;
1538 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1539 cleanup_entry(iter, net);
1540 xt_free_table_info(newinfo);
1541 return PTR_ERR(new_table);
1544 num_ops = hweight32(table->valid_hooks);
1550 ops = kmemdup_array(template_ops, num_ops, sizeof(*ops), GFP_KERNEL);
1556 for (i = 0; i < num_ops; i++)
1557 ops[i].priv = new_table;
1559 new_table->ops = ops;
1561 ret = nf_register_net_hooks(net, ops, num_ops);
1568 __arpt_unregister_table(net, new_table);
1572 void arpt_unregister_table_pre_exit(struct net *net, const char *name)
1574 struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name);
1577 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1579 EXPORT_SYMBOL(arpt_unregister_table_pre_exit);
1581 void arpt_unregister_table(struct net *net, const char *name)
1583 struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name);
1586 __arpt_unregister_table(net, table);
1589 /* The built-in targets: standard (NULL) and error. */
1590 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1592 .name = XT_STANDARD_TARGET,
1593 .targetsize = sizeof(int),
1594 .family = NFPROTO_ARP,
1595 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1596 .compatsize = sizeof(compat_int_t),
1597 .compat_from_user = compat_standard_from_user,
1598 .compat_to_user = compat_standard_to_user,
1602 .name = XT_ERROR_TARGET,
1603 .target = arpt_error,
1604 .targetsize = XT_FUNCTION_MAXNAMELEN,
1605 .family = NFPROTO_ARP,
1609 static struct nf_sockopt_ops arpt_sockopts = {
1611 .set_optmin = ARPT_BASE_CTL,
1612 .set_optmax = ARPT_SO_SET_MAX+1,
1613 .set = do_arpt_set_ctl,
1614 .get_optmin = ARPT_BASE_CTL,
1615 .get_optmax = ARPT_SO_GET_MAX+1,
1616 .get = do_arpt_get_ctl,
1617 .owner = THIS_MODULE,
1620 static int __net_init arp_tables_net_init(struct net *net)
1622 return xt_proto_init(net, NFPROTO_ARP);
1625 static void __net_exit arp_tables_net_exit(struct net *net)
1627 xt_proto_fini(net, NFPROTO_ARP);
1630 static struct pernet_operations arp_tables_net_ops = {
1631 .init = arp_tables_net_init,
1632 .exit = arp_tables_net_exit,
1635 static int __init arp_tables_init(void)
1639 ret = register_pernet_subsys(&arp_tables_net_ops);
1643 /* No one else will be downing sem now, so we won't sleep */
1644 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1648 /* Register setsockopt */
1649 ret = nf_register_sockopt(&arpt_sockopts);
1656 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1658 unregister_pernet_subsys(&arp_tables_net_ops);
1663 static void __exit arp_tables_fini(void)
1665 nf_unregister_sockopt(&arpt_sockopts);
1666 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1667 unregister_pernet_subsys(&arp_tables_net_ops);
1670 EXPORT_SYMBOL(arpt_register_table);
1671 EXPORT_SYMBOL(arpt_unregister_table);
1672 EXPORT_SYMBOL(arpt_do_table);
1674 module_init(arp_tables_init);
1675 module_exit(arp_tables_fini);