2 * Packet matching code for ARP packets.
4 * Based heavily, if not almost entirely, upon ip_tables.c framework.
6 * Some ARP specific bits are:
8 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
9 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
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>
27 #include <linux/uaccess.h>
29 #include <linux/netfilter/x_tables.h>
30 #include <linux/netfilter_arp/arp_tables.h>
31 #include "../../netfilter/xt_repldata.h"
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
35 MODULE_DESCRIPTION("arptables core");
37 void *arpt_alloc_initial_table(const struct xt_table *info)
39 return xt_alloc_initial_table(arpt, ARPT);
41 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
43 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
44 const char *hdr_addr, int len)
48 if (len > ARPT_DEV_ADDR_LEN_MAX)
49 len = ARPT_DEV_ADDR_LEN_MAX;
52 for (i = 0; i < len; i++)
53 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
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.
63 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
65 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
66 unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
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;
74 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
75 ret |= (a[i] ^ b[i]) & mask[i];
80 /* Returns whether packet matches rule or not. */
81 static inline int arp_packet_match(const struct arphdr *arphdr,
82 struct net_device *dev,
85 const struct arpt_arp *arpinfo)
87 const char *arpptr = (char *)(arphdr + 1);
88 const char *src_devaddr, *tgt_devaddr;
89 __be32 src_ipaddr, tgt_ipaddr;
92 if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
93 (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
96 if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
97 (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
100 if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
101 (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
104 if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
105 (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
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));
116 if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
117 arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
119 NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
120 arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
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))
130 /* Look for ifname matches. */
131 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
133 if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
136 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
138 if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
144 static inline int arp_checkentry(const struct arpt_arp *arp)
146 if (arp->flags & ~ARPT_F_MASK)
148 if (arp->invflags & ~ARPT_INV_MASK)
155 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
157 net_err_ratelimited("arp_tables: error: '%s'\n",
158 (const char *)par->targinfo);
163 static inline const struct xt_entry_target *
164 arpt_get_target_c(const struct arpt_entry *e)
166 return arpt_get_target((struct arpt_entry *)e);
169 static inline struct arpt_entry *
170 get_entry(const void *base, unsigned int offset)
172 return (struct arpt_entry *)(base + offset);
176 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
178 return (void *)entry + entry->next_offset;
181 unsigned int arpt_do_table(struct sk_buff *skb,
182 const struct nf_hook_state *state,
183 struct xt_table *table)
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;
197 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
200 indev = state->in ? state->in->name : nulldevname;
201 outdev = state->out ? state->out->name : nulldevname;
204 addend = xt_write_recseq_begin();
205 private = table->private;
206 cpu = smp_processor_id();
208 * Ensure we load private-> members after we've fetched the base
211 smp_read_barrier_depends();
212 table_base = private->entries;
213 jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
215 /* No TEE support for arptables, so no need to switch to alternate
216 * stack. All targets that reenter must return absolute verdicts.
218 e = get_entry(table_base, private->hook_entry[hook]);
221 acpar.hotdrop = false;
225 const struct xt_entry_target *t;
226 struct xt_counters *counter;
228 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
229 e = arpt_next_entry(e);
233 counter = xt_get_this_cpu_counter(&e->counters);
234 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
236 t = arpt_get_target_c(e);
238 /* Standard target? */
239 if (!t->u.kernel.target->target) {
242 v = ((struct xt_standard_target *)t)->verdict;
244 /* Pop from stack? */
245 if (v != XT_RETURN) {
246 verdict = (unsigned int)(-v) - 1;
250 e = get_entry(table_base,
251 private->underflow[hook]);
253 e = jumpstack[--stackidx];
254 e = arpt_next_entry(e);
259 != arpt_next_entry(e)) {
260 if (unlikely(stackidx >= private->stacksize)) {
264 jumpstack[stackidx++] = e;
267 e = get_entry(table_base, v);
271 acpar.target = t->u.kernel.target;
272 acpar.targinfo = t->data;
273 verdict = t->u.kernel.target->target(skb, &acpar);
275 if (verdict == XT_CONTINUE) {
276 /* Target might have changed stuff. */
278 e = arpt_next_entry(e);
283 } while (!acpar.hotdrop);
284 xt_write_recseq_end(addend);
293 /* All zeroes == unconditional rule. */
294 static inline bool unconditional(const struct arpt_entry *e)
296 static const struct arpt_arp uncond;
298 return e->target_offset == sizeof(struct arpt_entry) &&
299 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
302 /* Figures out from what hook each rule can be called: returns 0 if
303 * there are loops. Puts hook bitmask in comefrom.
305 static int mark_source_chains(const struct xt_table_info *newinfo,
306 unsigned int valid_hooks, void *entry0,
307 unsigned int *offsets)
311 /* No recursion; use packet counter to save back ptrs (reset
312 * to 0 as we leave), and comefrom to save source hook bitmask.
314 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
315 unsigned int pos = newinfo->hook_entry[hook];
316 struct arpt_entry *e = entry0 + pos;
318 if (!(valid_hooks & (1 << hook)))
321 /* Set initial back pointer. */
322 e->counters.pcnt = pos;
325 const struct xt_standard_target *t
326 = (void *)arpt_get_target_c(e);
327 int visited = e->comefrom & (1 << hook);
329 if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
333 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
335 /* Unconditional return/END. */
336 if ((unconditional(e) &&
337 (strcmp(t->target.u.user.name,
338 XT_STANDARD_TARGET) == 0) &&
339 t->verdict < 0) || visited) {
340 unsigned int oldpos, size;
342 if ((strcmp(t->target.u.user.name,
343 XT_STANDARD_TARGET) == 0) &&
344 t->verdict < -NF_MAX_VERDICT - 1)
347 /* Return: backtrack through the last
351 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
353 pos = e->counters.pcnt;
354 e->counters.pcnt = 0;
356 /* We're at the start. */
361 } while (oldpos == pos + e->next_offset);
364 size = e->next_offset;
365 e = entry0 + pos + size;
366 if (pos + size >= newinfo->size)
368 e->counters.pcnt = pos;
371 int newpos = t->verdict;
373 if (strcmp(t->target.u.user.name,
374 XT_STANDARD_TARGET) == 0 &&
376 /* This a jump; chase it. */
377 if (!xt_find_jump_offset(offsets, newpos,
382 /* ... this is a fallthru */
383 newpos = pos + e->next_offset;
384 if (newpos >= newinfo->size)
388 e->counters.pcnt = pos;
397 static int check_target(struct arpt_entry *e, struct net *net, const char *name)
399 struct xt_entry_target *t = arpt_get_target(e);
400 struct xt_tgchk_param par = {
404 .target = t->u.kernel.target,
406 .hook_mask = e->comefrom,
407 .family = NFPROTO_ARP,
410 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
414 find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
416 struct xt_percpu_counter_alloc_state *alloc_state)
418 struct xt_entry_target *t;
419 struct xt_target *target;
422 if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
425 t = arpt_get_target(e);
426 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
428 if (IS_ERR(target)) {
429 ret = PTR_ERR(target);
432 t->u.kernel.target = target;
434 ret = check_target(e, net, name);
439 module_put(t->u.kernel.target->me);
441 xt_percpu_counter_free(&e->counters);
446 static bool check_underflow(const struct arpt_entry *e)
448 const struct xt_entry_target *t;
449 unsigned int verdict;
451 if (!unconditional(e))
453 t = arpt_get_target_c(e);
454 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
456 verdict = ((struct xt_standard_target *)t)->verdict;
457 verdict = -verdict - 1;
458 return verdict == NF_DROP || verdict == NF_ACCEPT;
461 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
462 struct xt_table_info *newinfo,
463 const unsigned char *base,
464 const unsigned char *limit,
465 const unsigned int *hook_entries,
466 const unsigned int *underflows,
467 unsigned int valid_hooks)
472 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
473 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
474 (unsigned char *)e + e->next_offset > limit)
478 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
481 if (!arp_checkentry(&e->arp))
484 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
489 /* Check hooks & underflows */
490 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
491 if (!(valid_hooks & (1 << h)))
493 if ((unsigned char *)e - base == hook_entries[h])
494 newinfo->hook_entry[h] = hook_entries[h];
495 if ((unsigned char *)e - base == underflows[h]) {
496 if (!check_underflow(e))
499 newinfo->underflow[h] = underflows[h];
503 /* Clear counters and comefrom */
504 e->counters = ((struct xt_counters) { 0, 0 });
509 static void cleanup_entry(struct arpt_entry *e, struct net *net)
511 struct xt_tgdtor_param par;
512 struct xt_entry_target *t;
514 t = arpt_get_target(e);
516 par.target = t->u.kernel.target;
517 par.targinfo = t->data;
518 par.family = NFPROTO_ARP;
519 if (par.target->destroy != NULL)
520 par.target->destroy(&par);
521 module_put(par.target->me);
522 xt_percpu_counter_free(&e->counters);
525 /* Checks and translates the user-supplied table segment (held in
528 static int translate_table(struct net *net,
529 struct xt_table_info *newinfo,
531 const struct arpt_replace *repl)
533 struct xt_percpu_counter_alloc_state alloc_state = { 0 };
534 struct arpt_entry *iter;
535 unsigned int *offsets;
539 newinfo->size = repl->size;
540 newinfo->number = repl->num_entries;
542 /* Init all hooks to impossible value. */
543 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
544 newinfo->hook_entry[i] = 0xFFFFFFFF;
545 newinfo->underflow[i] = 0xFFFFFFFF;
548 offsets = xt_alloc_entry_offsets(newinfo->number);
553 /* Walk through entries, checking offsets. */
554 xt_entry_foreach(iter, entry0, newinfo->size) {
555 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
562 if (i < repl->num_entries)
563 offsets[i] = (void *)iter - entry0;
565 if (strcmp(arpt_get_target(iter)->u.user.name,
566 XT_ERROR_TARGET) == 0)
567 ++newinfo->stacksize;
571 if (i != repl->num_entries)
574 /* Check hooks all assigned */
575 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
576 /* Only hooks which are valid */
577 if (!(repl->valid_hooks & (1 << i)))
579 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
581 if (newinfo->underflow[i] == 0xFFFFFFFF)
585 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
591 /* Finally, each sanity check must pass */
593 xt_entry_foreach(iter, entry0, newinfo->size) {
594 ret = find_check_entry(iter, net, repl->name, repl->size,
602 xt_entry_foreach(iter, entry0, newinfo->size) {
605 cleanup_entry(iter, net);
616 static void get_counters(const struct xt_table_info *t,
617 struct xt_counters counters[])
619 struct arpt_entry *iter;
623 for_each_possible_cpu(cpu) {
624 seqcount_t *s = &per_cpu(xt_recseq, cpu);
627 xt_entry_foreach(iter, t->entries, t->size) {
628 struct xt_counters *tmp;
632 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
634 start = read_seqcount_begin(s);
637 } while (read_seqcount_retry(s, start));
639 ADD_COUNTER(counters[i], bcnt, pcnt);
646 static struct xt_counters *alloc_counters(const struct xt_table *table)
648 unsigned int countersize;
649 struct xt_counters *counters;
650 const struct xt_table_info *private = table->private;
652 /* We need atomic snapshot of counters: rest doesn't change
653 * (other than comefrom, which userspace doesn't care
656 countersize = sizeof(struct xt_counters) * private->number;
657 counters = vzalloc(countersize);
659 if (counters == NULL)
660 return ERR_PTR(-ENOMEM);
662 get_counters(private, counters);
667 static int copy_entries_to_user(unsigned int total_size,
668 const struct xt_table *table,
669 void __user *userptr)
671 unsigned int off, num;
672 const struct arpt_entry *e;
673 struct xt_counters *counters;
674 struct xt_table_info *private = table->private;
678 counters = alloc_counters(table);
679 if (IS_ERR(counters))
680 return PTR_ERR(counters);
682 loc_cpu_entry = private->entries;
684 /* FIXME: use iterator macros --RR */
685 /* ... then go back and fix counters and names */
686 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
687 const struct xt_entry_target *t;
689 e = loc_cpu_entry + off;
690 if (copy_to_user(userptr + off, e, sizeof(*e))) {
694 if (copy_to_user(userptr + off
695 + offsetof(struct arpt_entry, counters),
697 sizeof(counters[num])) != 0) {
702 t = arpt_get_target_c(e);
703 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
715 static void compat_standard_from_user(void *dst, const void *src)
717 int v = *(compat_int_t *)src;
720 v += xt_compat_calc_jump(NFPROTO_ARP, v);
721 memcpy(dst, &v, sizeof(v));
724 static int compat_standard_to_user(void __user *dst, const void *src)
726 compat_int_t cv = *(int *)src;
729 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
730 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
733 static int compat_calc_entry(const struct arpt_entry *e,
734 const struct xt_table_info *info,
735 const void *base, struct xt_table_info *newinfo)
737 const struct xt_entry_target *t;
738 unsigned int entry_offset;
741 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
742 entry_offset = (void *)e - base;
744 t = arpt_get_target_c(e);
745 off += xt_compat_target_offset(t->u.kernel.target);
746 newinfo->size -= off;
747 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
751 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
752 if (info->hook_entry[i] &&
753 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
754 newinfo->hook_entry[i] -= off;
755 if (info->underflow[i] &&
756 (e < (struct arpt_entry *)(base + info->underflow[i])))
757 newinfo->underflow[i] -= off;
762 static int compat_table_info(const struct xt_table_info *info,
763 struct xt_table_info *newinfo)
765 struct arpt_entry *iter;
766 const void *loc_cpu_entry;
769 if (!newinfo || !info)
772 /* we dont care about newinfo->entries */
773 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
774 newinfo->initial_entries = 0;
775 loc_cpu_entry = info->entries;
776 ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
779 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
780 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
788 static int get_info(struct net *net, void __user *user,
789 const int *len, int compat)
791 char name[XT_TABLE_MAXNAMELEN];
795 if (*len != sizeof(struct arpt_getinfo))
798 if (copy_from_user(name, user, sizeof(name)) != 0)
801 name[XT_TABLE_MAXNAMELEN-1] = '\0';
804 xt_compat_lock(NFPROTO_ARP);
806 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
807 "arptable_%s", name);
809 struct arpt_getinfo info;
810 const struct xt_table_info *private = t->private;
812 struct xt_table_info tmp;
815 ret = compat_table_info(private, &tmp);
816 xt_compat_flush_offsets(NFPROTO_ARP);
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);
830 if (copy_to_user(user, &info, *len) != 0)
840 xt_compat_unlock(NFPROTO_ARP);
845 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
849 struct arpt_get_entries get;
852 if (*len < sizeof(get))
854 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
856 if (*len != sizeof(struct arpt_get_entries) + get.size)
859 get.name[sizeof(get.name) - 1] = '\0';
861 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
863 const struct xt_table_info *private = t->private;
865 if (get.size == private->size)
866 ret = copy_entries_to_user(private->size,
867 t, uptr->entrytable);
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)
887 struct xt_table_info *oldinfo;
888 struct xt_counters *counters;
889 void *loc_cpu_old_entry;
890 struct arpt_entry *iter;
893 counters = xt_counters_alloc(num_counters);
899 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
900 "arptable_%s", 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))
924 /* Get the old counters, and synchronize with replace */
925 get_counters(oldinfo, counters);
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);
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");
945 free_newinfo_counters_untrans:
951 static int do_replace(struct net *net, const void __user *user,
955 struct arpt_replace tmp;
956 struct xt_table_info *newinfo;
958 struct arpt_entry *iter;
960 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
964 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
966 if (tmp.num_counters == 0)
969 tmp.name[sizeof(tmp.name)-1] = 0;
971 newinfo = xt_alloc_table_info(tmp.size);
975 loc_cpu_entry = newinfo->entries;
976 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
982 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
986 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
987 tmp.num_counters, tmp.counters);
989 goto free_newinfo_untrans;
992 free_newinfo_untrans:
993 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
994 cleanup_entry(iter, net);
996 xt_free_table_info(newinfo);
1000 static int do_add_counters(struct net *net, const void __user *user,
1001 unsigned int len, int compat)
1004 struct xt_counters_info tmp;
1005 struct xt_counters *paddc;
1007 const struct xt_table_info *private;
1009 struct arpt_entry *iter;
1010 unsigned int addend;
1012 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1014 return PTR_ERR(paddc);
1016 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1023 private = t->private;
1024 if (private->number != tmp.num_counters) {
1026 goto unlock_up_free;
1031 addend = xt_write_recseq_begin();
1032 xt_entry_foreach(iter, private->entries, private->size) {
1033 struct xt_counters *tmp;
1035 tmp = xt_get_this_cpu_counter(&iter->counters);
1036 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1039 xt_write_recseq_end(addend);
1050 #ifdef CONFIG_COMPAT
1051 struct compat_arpt_replace {
1052 char name[XT_TABLE_MAXNAMELEN];
1056 u32 hook_entry[NF_ARP_NUMHOOKS];
1057 u32 underflow[NF_ARP_NUMHOOKS];
1059 compat_uptr_t counters;
1060 struct compat_arpt_entry entries[0];
1063 static inline void compat_release_entry(struct compat_arpt_entry *e)
1065 struct xt_entry_target *t;
1067 t = compat_arpt_get_target(e);
1068 module_put(t->u.kernel.target->me);
1072 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1073 struct xt_table_info *newinfo,
1075 const unsigned char *base,
1076 const unsigned char *limit)
1078 struct xt_entry_target *t;
1079 struct xt_target *target;
1080 unsigned int entry_offset;
1083 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1084 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1085 (unsigned char *)e + e->next_offset > limit)
1088 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1089 sizeof(struct compat_xt_entry_target))
1092 if (!arp_checkentry(&e->arp))
1095 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1100 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1101 entry_offset = (void *)e - (void *)base;
1103 t = compat_arpt_get_target(e);
1104 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1105 t->u.user.revision);
1106 if (IS_ERR(target)) {
1107 ret = PTR_ERR(target);
1110 t->u.kernel.target = target;
1112 off += xt_compat_target_offset(target);
1114 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1116 goto release_target;
1121 module_put(t->u.kernel.target->me);
1127 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1129 struct xt_table_info *newinfo, unsigned char *base)
1131 struct xt_entry_target *t;
1132 struct arpt_entry *de;
1133 unsigned int origsize;
1138 memcpy(de, e, sizeof(struct arpt_entry));
1139 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1141 *dstptr += sizeof(struct arpt_entry);
1142 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1144 de->target_offset = e->target_offset - (origsize - *size);
1145 t = compat_arpt_get_target(e);
1146 xt_compat_target_from_user(t, dstptr, size);
1148 de->next_offset = e->next_offset - (origsize - *size);
1149 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1150 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1151 newinfo->hook_entry[h] -= origsize - *size;
1152 if ((unsigned char *)de - base < newinfo->underflow[h])
1153 newinfo->underflow[h] -= origsize - *size;
1157 static int translate_compat_table(struct net *net,
1158 struct xt_table_info **pinfo,
1160 const struct compat_arpt_replace *compatr)
1163 struct xt_table_info *newinfo, *info;
1164 void *pos, *entry0, *entry1;
1165 struct compat_arpt_entry *iter0;
1166 struct arpt_replace repl;
1172 size = compatr->size;
1173 info->number = compatr->num_entries;
1176 xt_compat_lock(NFPROTO_ARP);
1177 ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1180 /* Walk through entries, checking offsets. */
1181 xt_entry_foreach(iter0, entry0, compatr->size) {
1182 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1184 entry0 + compatr->size);
1191 if (j != compatr->num_entries)
1195 newinfo = xt_alloc_table_info(size);
1199 memset(newinfo->entries, 0, size);
1201 newinfo->number = compatr->num_entries;
1202 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1203 newinfo->hook_entry[i] = compatr->hook_entry[i];
1204 newinfo->underflow[i] = compatr->underflow[i];
1206 entry1 = newinfo->entries;
1208 size = compatr->size;
1209 xt_entry_foreach(iter0, entry0, compatr->size)
1210 compat_copy_entry_from_user(iter0, &pos, &size,
1213 /* all module references in entry0 are now gone */
1215 xt_compat_flush_offsets(NFPROTO_ARP);
1216 xt_compat_unlock(NFPROTO_ARP);
1218 memcpy(&repl, compatr, sizeof(*compatr));
1220 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1221 repl.hook_entry[i] = newinfo->hook_entry[i];
1222 repl.underflow[i] = newinfo->underflow[i];
1225 repl.num_counters = 0;
1226 repl.counters = NULL;
1227 repl.size = newinfo->size;
1228 ret = translate_table(net, newinfo, entry1, &repl);
1234 xt_free_table_info(info);
1238 xt_free_table_info(newinfo);
1241 xt_compat_flush_offsets(NFPROTO_ARP);
1242 xt_compat_unlock(NFPROTO_ARP);
1243 xt_entry_foreach(iter0, entry0, compatr->size) {
1246 compat_release_entry(iter0);
1251 static int compat_do_replace(struct net *net, void __user *user,
1255 struct compat_arpt_replace tmp;
1256 struct xt_table_info *newinfo;
1257 void *loc_cpu_entry;
1258 struct arpt_entry *iter;
1260 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1263 /* overflow check */
1264 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1266 if (tmp.num_counters == 0)
1269 tmp.name[sizeof(tmp.name)-1] = 0;
1271 newinfo = xt_alloc_table_info(tmp.size);
1275 loc_cpu_entry = newinfo->entries;
1276 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1281 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1285 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1286 tmp.num_counters, compat_ptr(tmp.counters));
1288 goto free_newinfo_untrans;
1291 free_newinfo_untrans:
1292 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1293 cleanup_entry(iter, net);
1295 xt_free_table_info(newinfo);
1299 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1304 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1308 case ARPT_SO_SET_REPLACE:
1309 ret = compat_do_replace(sock_net(sk), user, len);
1312 case ARPT_SO_SET_ADD_COUNTERS:
1313 ret = do_add_counters(sock_net(sk), user, len, 1);
1323 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1324 compat_uint_t *size,
1325 struct xt_counters *counters,
1328 struct xt_entry_target *t;
1329 struct compat_arpt_entry __user *ce;
1330 u_int16_t target_offset, next_offset;
1331 compat_uint_t origsize;
1336 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1337 copy_to_user(&ce->counters, &counters[i],
1338 sizeof(counters[i])) != 0)
1341 *dstptr += sizeof(struct compat_arpt_entry);
1342 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1344 target_offset = e->target_offset - (origsize - *size);
1346 t = arpt_get_target(e);
1347 ret = xt_compat_target_to_user(t, dstptr, size);
1350 next_offset = e->next_offset - (origsize - *size);
1351 if (put_user(target_offset, &ce->target_offset) != 0 ||
1352 put_user(next_offset, &ce->next_offset) != 0)
1357 static int compat_copy_entries_to_user(unsigned int total_size,
1358 struct xt_table *table,
1359 void __user *userptr)
1361 struct xt_counters *counters;
1362 const struct xt_table_info *private = table->private;
1367 struct arpt_entry *iter;
1369 counters = alloc_counters(table);
1370 if (IS_ERR(counters))
1371 return PTR_ERR(counters);
1375 xt_entry_foreach(iter, private->entries, total_size) {
1376 ret = compat_copy_entry_to_user(iter, &pos,
1377 &size, counters, i++);
1385 struct compat_arpt_get_entries {
1386 char name[XT_TABLE_MAXNAMELEN];
1388 struct compat_arpt_entry entrytable[0];
1391 static int compat_get_entries(struct net *net,
1392 struct compat_arpt_get_entries __user *uptr,
1396 struct compat_arpt_get_entries get;
1399 if (*len < sizeof(get))
1401 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1403 if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1406 get.name[sizeof(get.name) - 1] = '\0';
1408 xt_compat_lock(NFPROTO_ARP);
1409 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1411 const struct xt_table_info *private = t->private;
1412 struct xt_table_info info;
1414 ret = compat_table_info(private, &info);
1415 if (!ret && get.size == info.size) {
1416 ret = compat_copy_entries_to_user(private->size,
1417 t, uptr->entrytable);
1421 xt_compat_flush_offsets(NFPROTO_ARP);
1427 xt_compat_unlock(NFPROTO_ARP);
1431 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1433 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1438 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1442 case ARPT_SO_GET_INFO:
1443 ret = get_info(sock_net(sk), user, len, 1);
1445 case ARPT_SO_GET_ENTRIES:
1446 ret = compat_get_entries(sock_net(sk), user, len);
1449 ret = do_arpt_get_ctl(sk, cmd, user, len);
1455 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1459 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1463 case ARPT_SO_SET_REPLACE:
1464 ret = do_replace(sock_net(sk), user, len);
1467 case ARPT_SO_SET_ADD_COUNTERS:
1468 ret = do_add_counters(sock_net(sk), user, len, 0);
1478 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1482 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1486 case ARPT_SO_GET_INFO:
1487 ret = get_info(sock_net(sk), user, len, 0);
1490 case ARPT_SO_GET_ENTRIES:
1491 ret = get_entries(sock_net(sk), user, len);
1494 case ARPT_SO_GET_REVISION_TARGET: {
1495 struct xt_get_revision rev;
1497 if (*len != sizeof(rev)) {
1501 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1505 rev.name[sizeof(rev.name)-1] = 0;
1507 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1508 rev.revision, 1, &ret),
1509 "arpt_%s", rev.name);
1520 static void __arpt_unregister_table(struct net *net, struct xt_table *table)
1522 struct xt_table_info *private;
1523 void *loc_cpu_entry;
1524 struct module *table_owner = table->me;
1525 struct arpt_entry *iter;
1527 private = xt_unregister_table(table);
1529 /* Decrease module usage counts and free resources */
1530 loc_cpu_entry = private->entries;
1531 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1532 cleanup_entry(iter, net);
1533 if (private->number > private->initial_entries)
1534 module_put(table_owner);
1535 xt_free_table_info(private);
1538 int arpt_register_table(struct net *net,
1539 const struct xt_table *table,
1540 const struct arpt_replace *repl,
1541 const struct nf_hook_ops *ops,
1542 struct xt_table **res)
1545 struct xt_table_info *newinfo;
1546 struct xt_table_info bootstrap = {0};
1547 void *loc_cpu_entry;
1548 struct xt_table *new_table;
1550 newinfo = xt_alloc_table_info(repl->size);
1554 loc_cpu_entry = newinfo->entries;
1555 memcpy(loc_cpu_entry, repl->entries, repl->size);
1557 ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1561 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1562 if (IS_ERR(new_table)) {
1563 ret = PTR_ERR(new_table);
1567 /* set res now, will see skbs right after nf_register_net_hooks */
1568 WRITE_ONCE(*res, new_table);
1570 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1572 __arpt_unregister_table(net, new_table);
1579 xt_free_table_info(newinfo);
1583 void arpt_unregister_table(struct net *net, struct xt_table *table,
1584 const struct nf_hook_ops *ops)
1586 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1587 __arpt_unregister_table(net, table);
1590 /* The built-in targets: standard (NULL) and error. */
1591 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1593 .name = XT_STANDARD_TARGET,
1594 .targetsize = sizeof(int),
1595 .family = NFPROTO_ARP,
1596 #ifdef CONFIG_COMPAT
1597 .compatsize = sizeof(compat_int_t),
1598 .compat_from_user = compat_standard_from_user,
1599 .compat_to_user = compat_standard_to_user,
1603 .name = XT_ERROR_TARGET,
1604 .target = arpt_error,
1605 .targetsize = XT_FUNCTION_MAXNAMELEN,
1606 .family = NFPROTO_ARP,
1610 static struct nf_sockopt_ops arpt_sockopts = {
1612 .set_optmin = ARPT_BASE_CTL,
1613 .set_optmax = ARPT_SO_SET_MAX+1,
1614 .set = do_arpt_set_ctl,
1615 #ifdef CONFIG_COMPAT
1616 .compat_set = compat_do_arpt_set_ctl,
1618 .get_optmin = ARPT_BASE_CTL,
1619 .get_optmax = ARPT_SO_GET_MAX+1,
1620 .get = do_arpt_get_ctl,
1621 #ifdef CONFIG_COMPAT
1622 .compat_get = compat_do_arpt_get_ctl,
1624 .owner = THIS_MODULE,
1627 static int __net_init arp_tables_net_init(struct net *net)
1629 return xt_proto_init(net, NFPROTO_ARP);
1632 static void __net_exit arp_tables_net_exit(struct net *net)
1634 xt_proto_fini(net, NFPROTO_ARP);
1637 static struct pernet_operations arp_tables_net_ops = {
1638 .init = arp_tables_net_init,
1639 .exit = arp_tables_net_exit,
1642 static int __init arp_tables_init(void)
1646 ret = register_pernet_subsys(&arp_tables_net_ops);
1650 /* No one else will be downing sem now, so we won't sleep */
1651 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1655 /* Register setsockopt */
1656 ret = nf_register_sockopt(&arpt_sockopts);
1660 pr_info("arp_tables: (C) 2002 David S. Miller\n");
1664 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1666 unregister_pernet_subsys(&arp_tables_net_ops);
1671 static void __exit arp_tables_fini(void)
1673 nf_unregister_sockopt(&arpt_sockopts);
1674 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1675 unregister_pernet_subsys(&arp_tables_net_ops);
1678 EXPORT_SYMBOL(arpt_register_table);
1679 EXPORT_SYMBOL(arpt_unregister_table);
1680 EXPORT_SYMBOL(arpt_do_table);
1682 module_init(arp_tables_init);
1683 module_exit(arp_tables_fini);