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TOMOYO Linux Cross Reference
Linux/net/ipv4/netfilter/arp_tables.c

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  1 /*
  2  * Packet matching code for ARP packets.
  3  *
  4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
  5  *
  6  * Some ARP specific bits are:
  7  *
  8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
  9  * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
 10  *
 11  */
 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 13 #include <linux/kernel.h>
 14 #include <linux/skbuff.h>
 15 #include <linux/netdevice.h>
 16 #include <linux/capability.h>
 17 #include <linux/if_arp.h>
 18 #include <linux/kmod.h>
 19 #include <linux/vmalloc.h>
 20 #include <linux/proc_fs.h>
 21 #include <linux/module.h>
 22 #include <linux/init.h>
 23 #include <linux/mutex.h>
 24 #include <linux/err.h>
 25 #include <net/compat.h>
 26 #include <net/sock.h>
 27 #include <asm/uaccess.h>
 28 
 29 #include <linux/netfilter/x_tables.h>
 30 #include <linux/netfilter_arp/arp_tables.h>
 31 #include "../../netfilter/xt_repldata.h"
 32 
 33 MODULE_LICENSE("GPL");
 34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
 35 MODULE_DESCRIPTION("arptables core");
 36 
 37 /*#define DEBUG_ARP_TABLES*/
 38 /*#define DEBUG_ARP_TABLES_USER*/
 39 
 40 #ifdef DEBUG_ARP_TABLES
 41 #define dprintf(format, args...)  printk(format , ## args)
 42 #else
 43 #define dprintf(format, args...)
 44 #endif
 45 
 46 #ifdef DEBUG_ARP_TABLES_USER
 47 #define duprintf(format, args...) printk(format , ## args)
 48 #else
 49 #define duprintf(format, args...)
 50 #endif
 51 
 52 #ifdef CONFIG_NETFILTER_DEBUG
 53 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
 54 #else
 55 #define ARP_NF_ASSERT(x)
 56 #endif
 57 
 58 void *arpt_alloc_initial_table(const struct xt_table *info)
 59 {
 60         return xt_alloc_initial_table(arpt, ARPT);
 61 }
 62 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
 63 
 64 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
 65                                       const char *hdr_addr, int len)
 66 {
 67         int i, ret;
 68 
 69         if (len > ARPT_DEV_ADDR_LEN_MAX)
 70                 len = ARPT_DEV_ADDR_LEN_MAX;
 71 
 72         ret = 0;
 73         for (i = 0; i < len; i++)
 74                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
 75 
 76         return ret != 0;
 77 }
 78 
 79 /*
 80  * Unfortunately, _b and _mask are not aligned to an int (or long int)
 81  * Some arches dont care, unrolling the loop is a win on them.
 82  * For other arches, we only have a 16bit alignement.
 83  */
 84 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
 85 {
 86 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 87         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
 88 #else
 89         unsigned long ret = 0;
 90         const u16 *a = (const u16 *)_a;
 91         const u16 *b = (const u16 *)_b;
 92         const u16 *mask = (const u16 *)_mask;
 93         int i;
 94 
 95         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
 96                 ret |= (a[i] ^ b[i]) & mask[i];
 97 #endif
 98         return ret;
 99 }
100 
101 /* Returns whether packet matches rule or not. */
102 static inline int arp_packet_match(const struct arphdr *arphdr,
103                                    struct net_device *dev,
104                                    const char *indev,
105                                    const char *outdev,
106                                    const struct arpt_arp *arpinfo)
107 {
108         const char *arpptr = (char *)(arphdr + 1);
109         const char *src_devaddr, *tgt_devaddr;
110         __be32 src_ipaddr, tgt_ipaddr;
111         long ret;
112 
113 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
114 
115         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
116                   ARPT_INV_ARPOP)) {
117                 dprintf("ARP operation field mismatch.\n");
118                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
119                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
120                 return 0;
121         }
122 
123         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
124                   ARPT_INV_ARPHRD)) {
125                 dprintf("ARP hardware address format mismatch.\n");
126                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
127                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
128                 return 0;
129         }
130 
131         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
132                   ARPT_INV_ARPPRO)) {
133                 dprintf("ARP protocol address format mismatch.\n");
134                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
135                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
136                 return 0;
137         }
138 
139         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
140                   ARPT_INV_ARPHLN)) {
141                 dprintf("ARP hardware address length mismatch.\n");
142                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
143                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
144                 return 0;
145         }
146 
147         src_devaddr = arpptr;
148         arpptr += dev->addr_len;
149         memcpy(&src_ipaddr, arpptr, sizeof(u32));
150         arpptr += sizeof(u32);
151         tgt_devaddr = arpptr;
152         arpptr += dev->addr_len;
153         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
154 
155         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
156                   ARPT_INV_SRCDEVADDR) ||
157             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
158                   ARPT_INV_TGTDEVADDR)) {
159                 dprintf("Source or target device address mismatch.\n");
160 
161                 return 0;
162         }
163 
164         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
165                   ARPT_INV_SRCIP) ||
166             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
167                   ARPT_INV_TGTIP)) {
168                 dprintf("Source or target IP address mismatch.\n");
169 
170                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
171                         &src_ipaddr,
172                         &arpinfo->smsk.s_addr,
173                         &arpinfo->src.s_addr,
174                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
175                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
176                         &tgt_ipaddr,
177                         &arpinfo->tmsk.s_addr,
178                         &arpinfo->tgt.s_addr,
179                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
180                 return 0;
181         }
182 
183         /* Look for ifname matches.  */
184         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
185 
186         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
187                 dprintf("VIA in mismatch (%s vs %s).%s\n",
188                         indev, arpinfo->iniface,
189                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
190                 return 0;
191         }
192 
193         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
194 
195         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
196                 dprintf("VIA out mismatch (%s vs %s).%s\n",
197                         outdev, arpinfo->outiface,
198                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
199                 return 0;
200         }
201 
202         return 1;
203 #undef FWINV
204 }
205 
206 static inline int arp_checkentry(const struct arpt_arp *arp)
207 {
208         if (arp->flags & ~ARPT_F_MASK) {
209                 duprintf("Unknown flag bits set: %08X\n",
210                          arp->flags & ~ARPT_F_MASK);
211                 return 0;
212         }
213         if (arp->invflags & ~ARPT_INV_MASK) {
214                 duprintf("Unknown invflag bits set: %08X\n",
215                          arp->invflags & ~ARPT_INV_MASK);
216                 return 0;
217         }
218 
219         return 1;
220 }
221 
222 static unsigned int
223 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
224 {
225         net_err_ratelimited("arp_tables: error: '%s'\n",
226                             (const char *)par->targinfo);
227 
228         return NF_DROP;
229 }
230 
231 static inline const struct xt_entry_target *
232 arpt_get_target_c(const struct arpt_entry *e)
233 {
234         return arpt_get_target((struct arpt_entry *)e);
235 }
236 
237 static inline struct arpt_entry *
238 get_entry(const void *base, unsigned int offset)
239 {
240         return (struct arpt_entry *)(base + offset);
241 }
242 
243 static inline __pure
244 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
245 {
246         return (void *)entry + entry->next_offset;
247 }
248 
249 unsigned int arpt_do_table(struct sk_buff *skb,
250                            unsigned int hook,
251                            const struct net_device *in,
252                            const struct net_device *out,
253                            struct xt_table *table)
254 {
255         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
256         unsigned int verdict = NF_DROP;
257         const struct arphdr *arp;
258         struct arpt_entry *e, *back;
259         const char *indev, *outdev;
260         void *table_base;
261         const struct xt_table_info *private;
262         struct xt_action_param acpar;
263         unsigned int addend;
264 
265         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
266                 return NF_DROP;
267 
268         indev = in ? in->name : nulldevname;
269         outdev = out ? out->name : nulldevname;
270 
271         local_bh_disable();
272         addend = xt_write_recseq_begin();
273         private = table->private;
274         table_base = private->entries[smp_processor_id()];
275 
276         e = get_entry(table_base, private->hook_entry[hook]);
277         back = get_entry(table_base, private->underflow[hook]);
278 
279         acpar.in      = in;
280         acpar.out     = out;
281         acpar.hooknum = hook;
282         acpar.family  = NFPROTO_ARP;
283         acpar.hotdrop = false;
284 
285         arp = arp_hdr(skb);
286         do {
287                 const struct xt_entry_target *t;
288 
289                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
290                         e = arpt_next_entry(e);
291                         continue;
292                 }
293 
294                 ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
295 
296                 t = arpt_get_target_c(e);
297 
298                 /* Standard target? */
299                 if (!t->u.kernel.target->target) {
300                         int v;
301 
302                         v = ((struct xt_standard_target *)t)->verdict;
303                         if (v < 0) {
304                                 /* Pop from stack? */
305                                 if (v != XT_RETURN) {
306                                         verdict = (unsigned int)(-v) - 1;
307                                         break;
308                                 }
309                                 e = back;
310                                 back = get_entry(table_base, back->comefrom);
311                                 continue;
312                         }
313                         if (table_base + v
314                             != arpt_next_entry(e)) {
315                                 /* Save old back ptr in next entry */
316                                 struct arpt_entry *next = arpt_next_entry(e);
317                                 next->comefrom = (void *)back - table_base;
318 
319                                 /* set back pointer to next entry */
320                                 back = next;
321                         }
322 
323                         e = get_entry(table_base, v);
324                         continue;
325                 }
326 
327                 /* Targets which reenter must return
328                  * abs. verdicts
329                  */
330                 acpar.target   = t->u.kernel.target;
331                 acpar.targinfo = t->data;
332                 verdict = t->u.kernel.target->target(skb, &acpar);
333 
334                 /* Target might have changed stuff. */
335                 arp = arp_hdr(skb);
336 
337                 if (verdict == XT_CONTINUE)
338                         e = arpt_next_entry(e);
339                 else
340                         /* Verdict */
341                         break;
342         } while (!acpar.hotdrop);
343         xt_write_recseq_end(addend);
344         local_bh_enable();
345 
346         if (acpar.hotdrop)
347                 return NF_DROP;
348         else
349                 return verdict;
350 }
351 
352 /* All zeroes == unconditional rule. */
353 static inline bool unconditional(const struct arpt_arp *arp)
354 {
355         static const struct arpt_arp uncond;
356 
357         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
358 }
359 
360 /* Figures out from what hook each rule can be called: returns 0 if
361  * there are loops.  Puts hook bitmask in comefrom.
362  */
363 static int mark_source_chains(const struct xt_table_info *newinfo,
364                               unsigned int valid_hooks, void *entry0)
365 {
366         unsigned int hook;
367 
368         /* No recursion; use packet counter to save back ptrs (reset
369          * to 0 as we leave), and comefrom to save source hook bitmask.
370          */
371         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
372                 unsigned int pos = newinfo->hook_entry[hook];
373                 struct arpt_entry *e
374                         = (struct arpt_entry *)(entry0 + pos);
375 
376                 if (!(valid_hooks & (1 << hook)))
377                         continue;
378 
379                 /* Set initial back pointer. */
380                 e->counters.pcnt = pos;
381 
382                 for (;;) {
383                         const struct xt_standard_target *t
384                                 = (void *)arpt_get_target_c(e);
385                         int visited = e->comefrom & (1 << hook);
386 
387                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
388                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
389                                        hook, pos, e->comefrom);
390                                 return 0;
391                         }
392                         e->comefrom
393                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
394 
395                         /* Unconditional return/END. */
396                         if ((e->target_offset == sizeof(struct arpt_entry) &&
397                              (strcmp(t->target.u.user.name,
398                                      XT_STANDARD_TARGET) == 0) &&
399                              t->verdict < 0 && unconditional(&e->arp)) ||
400                             visited) {
401                                 unsigned int oldpos, size;
402 
403                                 if ((strcmp(t->target.u.user.name,
404                                             XT_STANDARD_TARGET) == 0) &&
405                                     t->verdict < -NF_MAX_VERDICT - 1) {
406                                         duprintf("mark_source_chains: bad "
407                                                 "negative verdict (%i)\n",
408                                                                 t->verdict);
409                                         return 0;
410                                 }
411 
412                                 /* Return: backtrack through the last
413                                  * big jump.
414                                  */
415                                 do {
416                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
417                                         oldpos = pos;
418                                         pos = e->counters.pcnt;
419                                         e->counters.pcnt = 0;
420 
421                                         /* We're at the start. */
422                                         if (pos == oldpos)
423                                                 goto next;
424 
425                                         e = (struct arpt_entry *)
426                                                 (entry0 + pos);
427                                 } while (oldpos == pos + e->next_offset);
428 
429                                 /* Move along one */
430                                 size = e->next_offset;
431                                 e = (struct arpt_entry *)
432                                         (entry0 + pos + size);
433                                 e->counters.pcnt = pos;
434                                 pos += size;
435                         } else {
436                                 int newpos = t->verdict;
437 
438                                 if (strcmp(t->target.u.user.name,
439                                            XT_STANDARD_TARGET) == 0 &&
440                                     newpos >= 0) {
441                                         if (newpos > newinfo->size -
442                                                 sizeof(struct arpt_entry)) {
443                                                 duprintf("mark_source_chains: "
444                                                         "bad verdict (%i)\n",
445                                                                 newpos);
446                                                 return 0;
447                                         }
448 
449                                         /* This a jump; chase it. */
450                                         duprintf("Jump rule %u -> %u\n",
451                                                  pos, newpos);
452                                 } else {
453                                         /* ... this is a fallthru */
454                                         newpos = pos + e->next_offset;
455                                 }
456                                 e = (struct arpt_entry *)
457                                         (entry0 + newpos);
458                                 e->counters.pcnt = pos;
459                                 pos = newpos;
460                         }
461                 }
462                 next:
463                 duprintf("Finished chain %u\n", hook);
464         }
465         return 1;
466 }
467 
468 static inline int check_entry(const struct arpt_entry *e, const char *name)
469 {
470         const struct xt_entry_target *t;
471 
472         if (!arp_checkentry(&e->arp)) {
473                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
474                 return -EINVAL;
475         }
476 
477         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
478                 return -EINVAL;
479 
480         t = arpt_get_target_c(e);
481         if (e->target_offset + t->u.target_size > e->next_offset)
482                 return -EINVAL;
483 
484         return 0;
485 }
486 
487 static inline int check_target(struct arpt_entry *e, const char *name)
488 {
489         struct xt_entry_target *t = arpt_get_target(e);
490         int ret;
491         struct xt_tgchk_param par = {
492                 .table     = name,
493                 .entryinfo = e,
494                 .target    = t->u.kernel.target,
495                 .targinfo  = t->data,
496                 .hook_mask = e->comefrom,
497                 .family    = NFPROTO_ARP,
498         };
499 
500         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
501         if (ret < 0) {
502                 duprintf("arp_tables: check failed for `%s'.\n",
503                          t->u.kernel.target->name);
504                 return ret;
505         }
506         return 0;
507 }
508 
509 static inline int
510 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
511 {
512         struct xt_entry_target *t;
513         struct xt_target *target;
514         int ret;
515 
516         ret = check_entry(e, name);
517         if (ret)
518                 return ret;
519 
520         t = arpt_get_target(e);
521         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
522                                         t->u.user.revision);
523         if (IS_ERR(target)) {
524                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
525                 ret = PTR_ERR(target);
526                 goto out;
527         }
528         t->u.kernel.target = target;
529 
530         ret = check_target(e, name);
531         if (ret)
532                 goto err;
533         return 0;
534 err:
535         module_put(t->u.kernel.target->me);
536 out:
537         return ret;
538 }
539 
540 static bool check_underflow(const struct arpt_entry *e)
541 {
542         const struct xt_entry_target *t;
543         unsigned int verdict;
544 
545         if (!unconditional(&e->arp))
546                 return false;
547         t = arpt_get_target_c(e);
548         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
549                 return false;
550         verdict = ((struct xt_standard_target *)t)->verdict;
551         verdict = -verdict - 1;
552         return verdict == NF_DROP || verdict == NF_ACCEPT;
553 }
554 
555 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
556                                              struct xt_table_info *newinfo,
557                                              const unsigned char *base,
558                                              const unsigned char *limit,
559                                              const unsigned int *hook_entries,
560                                              const unsigned int *underflows,
561                                              unsigned int valid_hooks)
562 {
563         unsigned int h;
564 
565         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
566             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
567                 duprintf("Bad offset %p\n", e);
568                 return -EINVAL;
569         }
570 
571         if (e->next_offset
572             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
573                 duprintf("checking: element %p size %u\n",
574                          e, e->next_offset);
575                 return -EINVAL;
576         }
577 
578         /* Check hooks & underflows */
579         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
580                 if (!(valid_hooks & (1 << h)))
581                         continue;
582                 if ((unsigned char *)e - base == hook_entries[h])
583                         newinfo->hook_entry[h] = hook_entries[h];
584                 if ((unsigned char *)e - base == underflows[h]) {
585                         if (!check_underflow(e)) {
586                                 pr_err("Underflows must be unconditional and "
587                                        "use the STANDARD target with "
588                                        "ACCEPT/DROP\n");
589                                 return -EINVAL;
590                         }
591                         newinfo->underflow[h] = underflows[h];
592                 }
593         }
594 
595         /* Clear counters and comefrom */
596         e->counters = ((struct xt_counters) { 0, 0 });
597         e->comefrom = 0;
598         return 0;
599 }
600 
601 static inline void cleanup_entry(struct arpt_entry *e)
602 {
603         struct xt_tgdtor_param par;
604         struct xt_entry_target *t;
605 
606         t = arpt_get_target(e);
607         par.target   = t->u.kernel.target;
608         par.targinfo = t->data;
609         par.family   = NFPROTO_ARP;
610         if (par.target->destroy != NULL)
611                 par.target->destroy(&par);
612         module_put(par.target->me);
613 }
614 
615 /* Checks and translates the user-supplied table segment (held in
616  * newinfo).
617  */
618 static int translate_table(struct xt_table_info *newinfo, void *entry0,
619                            const struct arpt_replace *repl)
620 {
621         struct arpt_entry *iter;
622         unsigned int i;
623         int ret = 0;
624 
625         newinfo->size = repl->size;
626         newinfo->number = repl->num_entries;
627 
628         /* Init all hooks to impossible value. */
629         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
630                 newinfo->hook_entry[i] = 0xFFFFFFFF;
631                 newinfo->underflow[i] = 0xFFFFFFFF;
632         }
633 
634         duprintf("translate_table: size %u\n", newinfo->size);
635         i = 0;
636 
637         /* Walk through entries, checking offsets. */
638         xt_entry_foreach(iter, entry0, newinfo->size) {
639                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
640                                                  entry0 + repl->size,
641                                                  repl->hook_entry,
642                                                  repl->underflow,
643                                                  repl->valid_hooks);
644                 if (ret != 0)
645                         break;
646                 ++i;
647                 if (strcmp(arpt_get_target(iter)->u.user.name,
648                     XT_ERROR_TARGET) == 0)
649                         ++newinfo->stacksize;
650         }
651         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
652         if (ret != 0)
653                 return ret;
654 
655         if (i != repl->num_entries) {
656                 duprintf("translate_table: %u not %u entries\n",
657                          i, repl->num_entries);
658                 return -EINVAL;
659         }
660 
661         /* Check hooks all assigned */
662         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
663                 /* Only hooks which are valid */
664                 if (!(repl->valid_hooks & (1 << i)))
665                         continue;
666                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
667                         duprintf("Invalid hook entry %u %u\n",
668                                  i, repl->hook_entry[i]);
669                         return -EINVAL;
670                 }
671                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
672                         duprintf("Invalid underflow %u %u\n",
673                                  i, repl->underflow[i]);
674                         return -EINVAL;
675                 }
676         }
677 
678         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
679                 duprintf("Looping hook\n");
680                 return -ELOOP;
681         }
682 
683         /* Finally, each sanity check must pass */
684         i = 0;
685         xt_entry_foreach(iter, entry0, newinfo->size) {
686                 ret = find_check_entry(iter, repl->name, repl->size);
687                 if (ret != 0)
688                         break;
689                 ++i;
690         }
691 
692         if (ret != 0) {
693                 xt_entry_foreach(iter, entry0, newinfo->size) {
694                         if (i-- == 0)
695                                 break;
696                         cleanup_entry(iter);
697                 }
698                 return ret;
699         }
700 
701         /* And one copy for every other CPU */
702         for_each_possible_cpu(i) {
703                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
704                         memcpy(newinfo->entries[i], entry0, newinfo->size);
705         }
706 
707         return ret;
708 }
709 
710 static void get_counters(const struct xt_table_info *t,
711                          struct xt_counters counters[])
712 {
713         struct arpt_entry *iter;
714         unsigned int cpu;
715         unsigned int i;
716 
717         for_each_possible_cpu(cpu) {
718                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
719 
720                 i = 0;
721                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
722                         u64 bcnt, pcnt;
723                         unsigned int start;
724 
725                         do {
726                                 start = read_seqcount_begin(s);
727                                 bcnt = iter->counters.bcnt;
728                                 pcnt = iter->counters.pcnt;
729                         } while (read_seqcount_retry(s, start));
730 
731                         ADD_COUNTER(counters[i], bcnt, pcnt);
732                         ++i;
733                 }
734         }
735 }
736 
737 static struct xt_counters *alloc_counters(const struct xt_table *table)
738 {
739         unsigned int countersize;
740         struct xt_counters *counters;
741         const struct xt_table_info *private = table->private;
742 
743         /* We need atomic snapshot of counters: rest doesn't change
744          * (other than comefrom, which userspace doesn't care
745          * about).
746          */
747         countersize = sizeof(struct xt_counters) * private->number;
748         counters = vzalloc(countersize);
749 
750         if (counters == NULL)
751                 return ERR_PTR(-ENOMEM);
752 
753         get_counters(private, counters);
754 
755         return counters;
756 }
757 
758 static int copy_entries_to_user(unsigned int total_size,
759                                 const struct xt_table *table,
760                                 void __user *userptr)
761 {
762         unsigned int off, num;
763         const struct arpt_entry *e;
764         struct xt_counters *counters;
765         struct xt_table_info *private = table->private;
766         int ret = 0;
767         void *loc_cpu_entry;
768 
769         counters = alloc_counters(table);
770         if (IS_ERR(counters))
771                 return PTR_ERR(counters);
772 
773         loc_cpu_entry = private->entries[raw_smp_processor_id()];
774         /* ... then copy entire thing ... */
775         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
776                 ret = -EFAULT;
777                 goto free_counters;
778         }
779 
780         /* FIXME: use iterator macros --RR */
781         /* ... then go back and fix counters and names */
782         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
783                 const struct xt_entry_target *t;
784 
785                 e = (struct arpt_entry *)(loc_cpu_entry + off);
786                 if (copy_to_user(userptr + off
787                                  + offsetof(struct arpt_entry, counters),
788                                  &counters[num],
789                                  sizeof(counters[num])) != 0) {
790                         ret = -EFAULT;
791                         goto free_counters;
792                 }
793 
794                 t = arpt_get_target_c(e);
795                 if (copy_to_user(userptr + off + e->target_offset
796                                  + offsetof(struct xt_entry_target,
797                                             u.user.name),
798                                  t->u.kernel.target->name,
799                                  strlen(t->u.kernel.target->name)+1) != 0) {
800                         ret = -EFAULT;
801                         goto free_counters;
802                 }
803         }
804 
805  free_counters:
806         vfree(counters);
807         return ret;
808 }
809 
810 #ifdef CONFIG_COMPAT
811 static void compat_standard_from_user(void *dst, const void *src)
812 {
813         int v = *(compat_int_t *)src;
814 
815         if (v > 0)
816                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
817         memcpy(dst, &v, sizeof(v));
818 }
819 
820 static int compat_standard_to_user(void __user *dst, const void *src)
821 {
822         compat_int_t cv = *(int *)src;
823 
824         if (cv > 0)
825                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
826         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
827 }
828 
829 static int compat_calc_entry(const struct arpt_entry *e,
830                              const struct xt_table_info *info,
831                              const void *base, struct xt_table_info *newinfo)
832 {
833         const struct xt_entry_target *t;
834         unsigned int entry_offset;
835         int off, i, ret;
836 
837         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
838         entry_offset = (void *)e - base;
839 
840         t = arpt_get_target_c(e);
841         off += xt_compat_target_offset(t->u.kernel.target);
842         newinfo->size -= off;
843         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
844         if (ret)
845                 return ret;
846 
847         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
848                 if (info->hook_entry[i] &&
849                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
850                         newinfo->hook_entry[i] -= off;
851                 if (info->underflow[i] &&
852                     (e < (struct arpt_entry *)(base + info->underflow[i])))
853                         newinfo->underflow[i] -= off;
854         }
855         return 0;
856 }
857 
858 static int compat_table_info(const struct xt_table_info *info,
859                              struct xt_table_info *newinfo)
860 {
861         struct arpt_entry *iter;
862         void *loc_cpu_entry;
863         int ret;
864 
865         if (!newinfo || !info)
866                 return -EINVAL;
867 
868         /* we dont care about newinfo->entries[] */
869         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
870         newinfo->initial_entries = 0;
871         loc_cpu_entry = info->entries[raw_smp_processor_id()];
872         xt_compat_init_offsets(NFPROTO_ARP, info->number);
873         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
874                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
875                 if (ret != 0)
876                         return ret;
877         }
878         return 0;
879 }
880 #endif
881 
882 static int get_info(struct net *net, void __user *user,
883                     const int *len, int compat)
884 {
885         char name[XT_TABLE_MAXNAMELEN];
886         struct xt_table *t;
887         int ret;
888 
889         if (*len != sizeof(struct arpt_getinfo)) {
890                 duprintf("length %u != %Zu\n", *len,
891                          sizeof(struct arpt_getinfo));
892                 return -EINVAL;
893         }
894 
895         if (copy_from_user(name, user, sizeof(name)) != 0)
896                 return -EFAULT;
897 
898         name[XT_TABLE_MAXNAMELEN-1] = '\0';
899 #ifdef CONFIG_COMPAT
900         if (compat)
901                 xt_compat_lock(NFPROTO_ARP);
902 #endif
903         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
904                                     "arptable_%s", name);
905         if (!IS_ERR_OR_NULL(t)) {
906                 struct arpt_getinfo info;
907                 const struct xt_table_info *private = t->private;
908 #ifdef CONFIG_COMPAT
909                 struct xt_table_info tmp;
910 
911                 if (compat) {
912                         ret = compat_table_info(private, &tmp);
913                         xt_compat_flush_offsets(NFPROTO_ARP);
914                         private = &tmp;
915                 }
916 #endif
917                 memset(&info, 0, sizeof(info));
918                 info.valid_hooks = t->valid_hooks;
919                 memcpy(info.hook_entry, private->hook_entry,
920                        sizeof(info.hook_entry));
921                 memcpy(info.underflow, private->underflow,
922                        sizeof(info.underflow));
923                 info.num_entries = private->number;
924                 info.size = private->size;
925                 strcpy(info.name, name);
926 
927                 if (copy_to_user(user, &info, *len) != 0)
928                         ret = -EFAULT;
929                 else
930                         ret = 0;
931                 xt_table_unlock(t);
932                 module_put(t->me);
933         } else
934                 ret = t ? PTR_ERR(t) : -ENOENT;
935 #ifdef CONFIG_COMPAT
936         if (compat)
937                 xt_compat_unlock(NFPROTO_ARP);
938 #endif
939         return ret;
940 }
941 
942 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
943                        const int *len)
944 {
945         int ret;
946         struct arpt_get_entries get;
947         struct xt_table *t;
948 
949         if (*len < sizeof(get)) {
950                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
951                 return -EINVAL;
952         }
953         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
954                 return -EFAULT;
955         if (*len != sizeof(struct arpt_get_entries) + get.size) {
956                 duprintf("get_entries: %u != %Zu\n", *len,
957                          sizeof(struct arpt_get_entries) + get.size);
958                 return -EINVAL;
959         }
960 
961         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
962         if (!IS_ERR_OR_NULL(t)) {
963                 const struct xt_table_info *private = t->private;
964 
965                 duprintf("t->private->number = %u\n",
966                          private->number);
967                 if (get.size == private->size)
968                         ret = copy_entries_to_user(private->size,
969                                                    t, uptr->entrytable);
970                 else {
971                         duprintf("get_entries: I've got %u not %u!\n",
972                                  private->size, get.size);
973                         ret = -EAGAIN;
974                 }
975                 module_put(t->me);
976                 xt_table_unlock(t);
977         } else
978                 ret = t ? PTR_ERR(t) : -ENOENT;
979 
980         return ret;
981 }
982 
983 static int __do_replace(struct net *net, const char *name,
984                         unsigned int valid_hooks,
985                         struct xt_table_info *newinfo,
986                         unsigned int num_counters,
987                         void __user *counters_ptr)
988 {
989         int ret;
990         struct xt_table *t;
991         struct xt_table_info *oldinfo;
992         struct xt_counters *counters;
993         void *loc_cpu_old_entry;
994         struct arpt_entry *iter;
995 
996         ret = 0;
997         counters = vzalloc(num_counters * sizeof(struct xt_counters));
998         if (!counters) {
999                 ret = -ENOMEM;
1000                 goto out;
1001         }
1002 
1003         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1004                                     "arptable_%s", name);
1005         if (IS_ERR_OR_NULL(t)) {
1006                 ret = t ? PTR_ERR(t) : -ENOENT;
1007                 goto free_newinfo_counters_untrans;
1008         }
1009 
1010         /* You lied! */
1011         if (valid_hooks != t->valid_hooks) {
1012                 duprintf("Valid hook crap: %08X vs %08X\n",
1013                          valid_hooks, t->valid_hooks);
1014                 ret = -EINVAL;
1015                 goto put_module;
1016         }
1017 
1018         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1019         if (!oldinfo)
1020                 goto put_module;
1021 
1022         /* Update module usage count based on number of rules */
1023         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1024                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1025         if ((oldinfo->number > oldinfo->initial_entries) ||
1026             (newinfo->number <= oldinfo->initial_entries))
1027                 module_put(t->me);
1028         if ((oldinfo->number > oldinfo->initial_entries) &&
1029             (newinfo->number <= oldinfo->initial_entries))
1030                 module_put(t->me);
1031 
1032         /* Get the old counters, and synchronize with replace */
1033         get_counters(oldinfo, counters);
1034 
1035         /* Decrease module usage counts and free resource */
1036         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1037         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1038                 cleanup_entry(iter);
1039 
1040         xt_free_table_info(oldinfo);
1041         if (copy_to_user(counters_ptr, counters,
1042                          sizeof(struct xt_counters) * num_counters) != 0)
1043                 ret = -EFAULT;
1044         vfree(counters);
1045         xt_table_unlock(t);
1046         return ret;
1047 
1048  put_module:
1049         module_put(t->me);
1050         xt_table_unlock(t);
1051  free_newinfo_counters_untrans:
1052         vfree(counters);
1053  out:
1054         return ret;
1055 }
1056 
1057 static int do_replace(struct net *net, const void __user *user,
1058                       unsigned int len)
1059 {
1060         int ret;
1061         struct arpt_replace tmp;
1062         struct xt_table_info *newinfo;
1063         void *loc_cpu_entry;
1064         struct arpt_entry *iter;
1065 
1066         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1067                 return -EFAULT;
1068 
1069         /* overflow check */
1070         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1071                 return -ENOMEM;
1072         tmp.name[sizeof(tmp.name)-1] = 0;
1073 
1074         newinfo = xt_alloc_table_info(tmp.size);
1075         if (!newinfo)
1076                 return -ENOMEM;
1077 
1078         /* choose the copy that is on our node/cpu */
1079         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1080         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1081                            tmp.size) != 0) {
1082                 ret = -EFAULT;
1083                 goto free_newinfo;
1084         }
1085 
1086         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1087         if (ret != 0)
1088                 goto free_newinfo;
1089 
1090         duprintf("arp_tables: Translated table\n");
1091 
1092         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1093                            tmp.num_counters, tmp.counters);
1094         if (ret)
1095                 goto free_newinfo_untrans;
1096         return 0;
1097 
1098  free_newinfo_untrans:
1099         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1100                 cleanup_entry(iter);
1101  free_newinfo:
1102         xt_free_table_info(newinfo);
1103         return ret;
1104 }
1105 
1106 static int do_add_counters(struct net *net, const void __user *user,
1107                            unsigned int len, int compat)
1108 {
1109         unsigned int i, curcpu;
1110         struct xt_counters_info tmp;
1111         struct xt_counters *paddc;
1112         unsigned int num_counters;
1113         const char *name;
1114         int size;
1115         void *ptmp;
1116         struct xt_table *t;
1117         const struct xt_table_info *private;
1118         int ret = 0;
1119         void *loc_cpu_entry;
1120         struct arpt_entry *iter;
1121         unsigned int addend;
1122 #ifdef CONFIG_COMPAT
1123         struct compat_xt_counters_info compat_tmp;
1124 
1125         if (compat) {
1126                 ptmp = &compat_tmp;
1127                 size = sizeof(struct compat_xt_counters_info);
1128         } else
1129 #endif
1130         {
1131                 ptmp = &tmp;
1132                 size = sizeof(struct xt_counters_info);
1133         }
1134 
1135         if (copy_from_user(ptmp, user, size) != 0)
1136                 return -EFAULT;
1137 
1138 #ifdef CONFIG_COMPAT
1139         if (compat) {
1140                 num_counters = compat_tmp.num_counters;
1141                 name = compat_tmp.name;
1142         } else
1143 #endif
1144         {
1145                 num_counters = tmp.num_counters;
1146                 name = tmp.name;
1147         }
1148 
1149         if (len != size + num_counters * sizeof(struct xt_counters))
1150                 return -EINVAL;
1151 
1152         paddc = vmalloc(len - size);
1153         if (!paddc)
1154                 return -ENOMEM;
1155 
1156         if (copy_from_user(paddc, user + size, len - size) != 0) {
1157                 ret = -EFAULT;
1158                 goto free;
1159         }
1160 
1161         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1162         if (IS_ERR_OR_NULL(t)) {
1163                 ret = t ? PTR_ERR(t) : -ENOENT;
1164                 goto free;
1165         }
1166 
1167         local_bh_disable();
1168         private = t->private;
1169         if (private->number != num_counters) {
1170                 ret = -EINVAL;
1171                 goto unlock_up_free;
1172         }
1173 
1174         i = 0;
1175         /* Choose the copy that is on our node */
1176         curcpu = smp_processor_id();
1177         loc_cpu_entry = private->entries[curcpu];
1178         addend = xt_write_recseq_begin();
1179         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1180                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1181                 ++i;
1182         }
1183         xt_write_recseq_end(addend);
1184  unlock_up_free:
1185         local_bh_enable();
1186         xt_table_unlock(t);
1187         module_put(t->me);
1188  free:
1189         vfree(paddc);
1190 
1191         return ret;
1192 }
1193 
1194 #ifdef CONFIG_COMPAT
1195 static inline void compat_release_entry(struct compat_arpt_entry *e)
1196 {
1197         struct xt_entry_target *t;
1198 
1199         t = compat_arpt_get_target(e);
1200         module_put(t->u.kernel.target->me);
1201 }
1202 
1203 static inline int
1204 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1205                                   struct xt_table_info *newinfo,
1206                                   unsigned int *size,
1207                                   const unsigned char *base,
1208                                   const unsigned char *limit,
1209                                   const unsigned int *hook_entries,
1210                                   const unsigned int *underflows,
1211                                   const char *name)
1212 {
1213         struct xt_entry_target *t;
1214         struct xt_target *target;
1215         unsigned int entry_offset;
1216         int ret, off, h;
1217 
1218         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1219         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1220             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1221                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1222                 return -EINVAL;
1223         }
1224 
1225         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1226                              sizeof(struct compat_xt_entry_target)) {
1227                 duprintf("checking: element %p size %u\n",
1228                          e, e->next_offset);
1229                 return -EINVAL;
1230         }
1231 
1232         /* For purposes of check_entry casting the compat entry is fine */
1233         ret = check_entry((struct arpt_entry *)e, name);
1234         if (ret)
1235                 return ret;
1236 
1237         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1238         entry_offset = (void *)e - (void *)base;
1239 
1240         t = compat_arpt_get_target(e);
1241         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1242                                         t->u.user.revision);
1243         if (IS_ERR(target)) {
1244                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1245                          t->u.user.name);
1246                 ret = PTR_ERR(target);
1247                 goto out;
1248         }
1249         t->u.kernel.target = target;
1250 
1251         off += xt_compat_target_offset(target);
1252         *size += off;
1253         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1254         if (ret)
1255                 goto release_target;
1256 
1257         /* Check hooks & underflows */
1258         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1259                 if ((unsigned char *)e - base == hook_entries[h])
1260                         newinfo->hook_entry[h] = hook_entries[h];
1261                 if ((unsigned char *)e - base == underflows[h])
1262                         newinfo->underflow[h] = underflows[h];
1263         }
1264 
1265         /* Clear counters and comefrom */
1266         memset(&e->counters, 0, sizeof(e->counters));
1267         e->comefrom = 0;
1268         return 0;
1269 
1270 release_target:
1271         module_put(t->u.kernel.target->me);
1272 out:
1273         return ret;
1274 }
1275 
1276 static int
1277 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1278                             unsigned int *size, const char *name,
1279                             struct xt_table_info *newinfo, unsigned char *base)
1280 {
1281         struct xt_entry_target *t;
1282         struct xt_target *target;
1283         struct arpt_entry *de;
1284         unsigned int origsize;
1285         int ret, h;
1286 
1287         ret = 0;
1288         origsize = *size;
1289         de = (struct arpt_entry *)*dstptr;
1290         memcpy(de, e, sizeof(struct arpt_entry));
1291         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1292 
1293         *dstptr += sizeof(struct arpt_entry);
1294         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1295 
1296         de->target_offset = e->target_offset - (origsize - *size);
1297         t = compat_arpt_get_target(e);
1298         target = t->u.kernel.target;
1299         xt_compat_target_from_user(t, dstptr, size);
1300 
1301         de->next_offset = e->next_offset - (origsize - *size);
1302         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1303                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1304                         newinfo->hook_entry[h] -= origsize - *size;
1305                 if ((unsigned char *)de - base < newinfo->underflow[h])
1306                         newinfo->underflow[h] -= origsize - *size;
1307         }
1308         return ret;
1309 }
1310 
1311 static int translate_compat_table(const char *name,
1312                                   unsigned int valid_hooks,
1313                                   struct xt_table_info **pinfo,
1314                                   void **pentry0,
1315                                   unsigned int total_size,
1316                                   unsigned int number,
1317                                   unsigned int *hook_entries,
1318                                   unsigned int *underflows)
1319 {
1320         unsigned int i, j;
1321         struct xt_table_info *newinfo, *info;
1322         void *pos, *entry0, *entry1;
1323         struct compat_arpt_entry *iter0;
1324         struct arpt_entry *iter1;
1325         unsigned int size;
1326         int ret = 0;
1327 
1328         info = *pinfo;
1329         entry0 = *pentry0;
1330         size = total_size;
1331         info->number = number;
1332 
1333         /* Init all hooks to impossible value. */
1334         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1335                 info->hook_entry[i] = 0xFFFFFFFF;
1336                 info->underflow[i] = 0xFFFFFFFF;
1337         }
1338 
1339         duprintf("translate_compat_table: size %u\n", info->size);
1340         j = 0;
1341         xt_compat_lock(NFPROTO_ARP);
1342         xt_compat_init_offsets(NFPROTO_ARP, number);
1343         /* Walk through entries, checking offsets. */
1344         xt_entry_foreach(iter0, entry0, total_size) {
1345                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1346                                                         entry0,
1347                                                         entry0 + total_size,
1348                                                         hook_entries,
1349                                                         underflows,
1350                                                         name);
1351                 if (ret != 0)
1352                         goto out_unlock;
1353                 ++j;
1354         }
1355 
1356         ret = -EINVAL;
1357         if (j != number) {
1358                 duprintf("translate_compat_table: %u not %u entries\n",
1359                          j, number);
1360                 goto out_unlock;
1361         }
1362 
1363         /* Check hooks all assigned */
1364         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1365                 /* Only hooks which are valid */
1366                 if (!(valid_hooks & (1 << i)))
1367                         continue;
1368                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1369                         duprintf("Invalid hook entry %u %u\n",
1370                                  i, hook_entries[i]);
1371                         goto out_unlock;
1372                 }
1373                 if (info->underflow[i] == 0xFFFFFFFF) {
1374                         duprintf("Invalid underflow %u %u\n",
1375                                  i, underflows[i]);
1376                         goto out_unlock;
1377                 }
1378         }
1379 
1380         ret = -ENOMEM;
1381         newinfo = xt_alloc_table_info(size);
1382         if (!newinfo)
1383                 goto out_unlock;
1384 
1385         newinfo->number = number;
1386         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1387                 newinfo->hook_entry[i] = info->hook_entry[i];
1388                 newinfo->underflow[i] = info->underflow[i];
1389         }
1390         entry1 = newinfo->entries[raw_smp_processor_id()];
1391         pos = entry1;
1392         size = total_size;
1393         xt_entry_foreach(iter0, entry0, total_size) {
1394                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1395                                                   name, newinfo, entry1);
1396                 if (ret != 0)
1397                         break;
1398         }
1399         xt_compat_flush_offsets(NFPROTO_ARP);
1400         xt_compat_unlock(NFPROTO_ARP);
1401         if (ret)
1402                 goto free_newinfo;
1403 
1404         ret = -ELOOP;
1405         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1406                 goto free_newinfo;
1407 
1408         i = 0;
1409         xt_entry_foreach(iter1, entry1, newinfo->size) {
1410                 ret = check_target(iter1, name);
1411                 if (ret != 0)
1412                         break;
1413                 ++i;
1414                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1415                     XT_ERROR_TARGET) == 0)
1416                         ++newinfo->stacksize;
1417         }
1418         if (ret) {
1419                 /*
1420                  * The first i matches need cleanup_entry (calls ->destroy)
1421                  * because they had called ->check already. The other j-i
1422                  * entries need only release.
1423                  */
1424                 int skip = i;
1425                 j -= i;
1426                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1427                         if (skip-- > 0)
1428                                 continue;
1429                         if (j-- == 0)
1430                                 break;
1431                         compat_release_entry(iter0);
1432                 }
1433                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1434                         if (i-- == 0)
1435                                 break;
1436                         cleanup_entry(iter1);
1437                 }
1438                 xt_free_table_info(newinfo);
1439                 return ret;
1440         }
1441 
1442         /* And one copy for every other CPU */
1443         for_each_possible_cpu(i)
1444                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1445                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1446 
1447         *pinfo = newinfo;
1448         *pentry0 = entry1;
1449         xt_free_table_info(info);
1450         return 0;
1451 
1452 free_newinfo:
1453         xt_free_table_info(newinfo);
1454 out:
1455         xt_entry_foreach(iter0, entry0, total_size) {
1456                 if (j-- == 0)
1457                         break;
1458                 compat_release_entry(iter0);
1459         }
1460         return ret;
1461 out_unlock:
1462         xt_compat_flush_offsets(NFPROTO_ARP);
1463         xt_compat_unlock(NFPROTO_ARP);
1464         goto out;
1465 }
1466 
1467 struct compat_arpt_replace {
1468         char                            name[XT_TABLE_MAXNAMELEN];
1469         u32                             valid_hooks;
1470         u32                             num_entries;
1471         u32                             size;
1472         u32                             hook_entry[NF_ARP_NUMHOOKS];
1473         u32                             underflow[NF_ARP_NUMHOOKS];
1474         u32                             num_counters;
1475         compat_uptr_t                   counters;
1476         struct compat_arpt_entry        entries[0];
1477 };
1478 
1479 static int compat_do_replace(struct net *net, void __user *user,
1480                              unsigned int len)
1481 {
1482         int ret;
1483         struct compat_arpt_replace tmp;
1484         struct xt_table_info *newinfo;
1485         void *loc_cpu_entry;
1486         struct arpt_entry *iter;
1487 
1488         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1489                 return -EFAULT;
1490 
1491         /* overflow check */
1492         if (tmp.size >= INT_MAX / num_possible_cpus())
1493                 return -ENOMEM;
1494         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1495                 return -ENOMEM;
1496         tmp.name[sizeof(tmp.name)-1] = 0;
1497 
1498         newinfo = xt_alloc_table_info(tmp.size);
1499         if (!newinfo)
1500                 return -ENOMEM;
1501 
1502         /* choose the copy that is on our node/cpu */
1503         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1504         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1505                 ret = -EFAULT;
1506                 goto free_newinfo;
1507         }
1508 
1509         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1510                                      &newinfo, &loc_cpu_entry, tmp.size,
1511                                      tmp.num_entries, tmp.hook_entry,
1512                                      tmp.underflow);
1513         if (ret != 0)
1514                 goto free_newinfo;
1515 
1516         duprintf("compat_do_replace: Translated table\n");
1517 
1518         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1519                            tmp.num_counters, compat_ptr(tmp.counters));
1520         if (ret)
1521                 goto free_newinfo_untrans;
1522         return 0;
1523 
1524  free_newinfo_untrans:
1525         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1526                 cleanup_entry(iter);
1527  free_newinfo:
1528         xt_free_table_info(newinfo);
1529         return ret;
1530 }
1531 
1532 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1533                                   unsigned int len)
1534 {
1535         int ret;
1536 
1537         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1538                 return -EPERM;
1539 
1540         switch (cmd) {
1541         case ARPT_SO_SET_REPLACE:
1542                 ret = compat_do_replace(sock_net(sk), user, len);
1543                 break;
1544 
1545         case ARPT_SO_SET_ADD_COUNTERS:
1546                 ret = do_add_counters(sock_net(sk), user, len, 1);
1547                 break;
1548 
1549         default:
1550                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1551                 ret = -EINVAL;
1552         }
1553 
1554         return ret;
1555 }
1556 
1557 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1558                                      compat_uint_t *size,
1559                                      struct xt_counters *counters,
1560                                      unsigned int i)
1561 {
1562         struct xt_entry_target *t;
1563         struct compat_arpt_entry __user *ce;
1564         u_int16_t target_offset, next_offset;
1565         compat_uint_t origsize;
1566         int ret;
1567 
1568         origsize = *size;
1569         ce = (struct compat_arpt_entry __user *)*dstptr;
1570         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1571             copy_to_user(&ce->counters, &counters[i],
1572             sizeof(counters[i])) != 0)
1573                 return -EFAULT;
1574 
1575         *dstptr += sizeof(struct compat_arpt_entry);
1576         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1577 
1578         target_offset = e->target_offset - (origsize - *size);
1579 
1580         t = arpt_get_target(e);
1581         ret = xt_compat_target_to_user(t, dstptr, size);
1582         if (ret)
1583                 return ret;
1584         next_offset = e->next_offset - (origsize - *size);
1585         if (put_user(target_offset, &ce->target_offset) != 0 ||
1586             put_user(next_offset, &ce->next_offset) != 0)
1587                 return -EFAULT;
1588         return 0;
1589 }
1590 
1591 static int compat_copy_entries_to_user(unsigned int total_size,
1592                                        struct xt_table *table,
1593                                        void __user *userptr)
1594 {
1595         struct xt_counters *counters;
1596         const struct xt_table_info *private = table->private;
1597         void __user *pos;
1598         unsigned int size;
1599         int ret = 0;
1600         void *loc_cpu_entry;
1601         unsigned int i = 0;
1602         struct arpt_entry *iter;
1603 
1604         counters = alloc_counters(table);
1605         if (IS_ERR(counters))
1606                 return PTR_ERR(counters);
1607 
1608         /* choose the copy on our node/cpu */
1609         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1610         pos = userptr;
1611         size = total_size;
1612         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1613                 ret = compat_copy_entry_to_user(iter, &pos,
1614                                                 &size, counters, i++);
1615                 if (ret != 0)
1616                         break;
1617         }
1618         vfree(counters);
1619         return ret;
1620 }
1621 
1622 struct compat_arpt_get_entries {
1623         char name[XT_TABLE_MAXNAMELEN];
1624         compat_uint_t size;
1625         struct compat_arpt_entry entrytable[0];
1626 };
1627 
1628 static int compat_get_entries(struct net *net,
1629                               struct compat_arpt_get_entries __user *uptr,
1630                               int *len)
1631 {
1632         int ret;
1633         struct compat_arpt_get_entries get;
1634         struct xt_table *t;
1635 
1636         if (*len < sizeof(get)) {
1637                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1638                 return -EINVAL;
1639         }
1640         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1641                 return -EFAULT;
1642         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1643                 duprintf("compat_get_entries: %u != %zu\n",
1644                          *len, sizeof(get) + get.size);
1645                 return -EINVAL;
1646         }
1647 
1648         xt_compat_lock(NFPROTO_ARP);
1649         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1650         if (!IS_ERR_OR_NULL(t)) {
1651                 const struct xt_table_info *private = t->private;
1652                 struct xt_table_info info;
1653 
1654                 duprintf("t->private->number = %u\n", private->number);
1655                 ret = compat_table_info(private, &info);
1656                 if (!ret && get.size == info.size) {
1657                         ret = compat_copy_entries_to_user(private->size,
1658                                                           t, uptr->entrytable);
1659                 } else if (!ret) {
1660                         duprintf("compat_get_entries: I've got %u not %u!\n",
1661                                  private->size, get.size);
1662                         ret = -EAGAIN;
1663                 }
1664                 xt_compat_flush_offsets(NFPROTO_ARP);
1665                 module_put(t->me);
1666                 xt_table_unlock(t);
1667         } else
1668                 ret = t ? PTR_ERR(t) : -ENOENT;
1669 
1670         xt_compat_unlock(NFPROTO_ARP);
1671         return ret;
1672 }
1673 
1674 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1675 
1676 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1677                                   int *len)
1678 {
1679         int ret;
1680 
1681         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1682                 return -EPERM;
1683 
1684         switch (cmd) {
1685         case ARPT_SO_GET_INFO:
1686                 ret = get_info(sock_net(sk), user, len, 1);
1687                 break;
1688         case ARPT_SO_GET_ENTRIES:
1689                 ret = compat_get_entries(sock_net(sk), user, len);
1690                 break;
1691         default:
1692                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1693         }
1694         return ret;
1695 }
1696 #endif
1697 
1698 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1699 {
1700         int ret;
1701 
1702         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1703                 return -EPERM;
1704 
1705         switch (cmd) {
1706         case ARPT_SO_SET_REPLACE:
1707                 ret = do_replace(sock_net(sk), user, len);
1708                 break;
1709 
1710         case ARPT_SO_SET_ADD_COUNTERS:
1711                 ret = do_add_counters(sock_net(sk), user, len, 0);
1712                 break;
1713 
1714         default:
1715                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1716                 ret = -EINVAL;
1717         }
1718 
1719         return ret;
1720 }
1721 
1722 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1723 {
1724         int ret;
1725 
1726         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1727                 return -EPERM;
1728 
1729         switch (cmd) {
1730         case ARPT_SO_GET_INFO:
1731                 ret = get_info(sock_net(sk), user, len, 0);
1732                 break;
1733 
1734         case ARPT_SO_GET_ENTRIES:
1735                 ret = get_entries(sock_net(sk), user, len);
1736                 break;
1737 
1738         case ARPT_SO_GET_REVISION_TARGET: {
1739                 struct xt_get_revision rev;
1740 
1741                 if (*len != sizeof(rev)) {
1742                         ret = -EINVAL;
1743                         break;
1744                 }
1745                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1746                         ret = -EFAULT;
1747                         break;
1748                 }
1749                 rev.name[sizeof(rev.name)-1] = 0;
1750 
1751                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1752                                                          rev.revision, 1, &ret),
1753                                         "arpt_%s", rev.name);
1754                 break;
1755         }
1756 
1757         default:
1758                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1759                 ret = -EINVAL;
1760         }
1761 
1762         return ret;
1763 }
1764 
1765 struct xt_table *arpt_register_table(struct net *net,
1766                                      const struct xt_table *table,
1767                                      const struct arpt_replace *repl)
1768 {
1769         int ret;
1770         struct xt_table_info *newinfo;
1771         struct xt_table_info bootstrap = {0};
1772         void *loc_cpu_entry;
1773         struct xt_table *new_table;
1774 
1775         newinfo = xt_alloc_table_info(repl->size);
1776         if (!newinfo) {
1777                 ret = -ENOMEM;
1778                 goto out;
1779         }
1780 
1781         /* choose the copy on our node/cpu */
1782         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1783         memcpy(loc_cpu_entry, repl->entries, repl->size);
1784 
1785         ret = translate_table(newinfo, loc_cpu_entry, repl);
1786         duprintf("arpt_register_table: translate table gives %d\n", ret);
1787         if (ret != 0)
1788                 goto out_free;
1789 
1790         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1791         if (IS_ERR(new_table)) {
1792                 ret = PTR_ERR(new_table);
1793                 goto out_free;
1794         }
1795         return new_table;
1796 
1797 out_free:
1798         xt_free_table_info(newinfo);
1799 out:
1800         return ERR_PTR(ret);
1801 }
1802 
1803 void arpt_unregister_table(struct xt_table *table)
1804 {
1805         struct xt_table_info *private;
1806         void *loc_cpu_entry;
1807         struct module *table_owner = table->me;
1808         struct arpt_entry *iter;
1809 
1810         private = xt_unregister_table(table);
1811 
1812         /* Decrease module usage counts and free resources */
1813         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1814         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1815                 cleanup_entry(iter);
1816         if (private->number > private->initial_entries)
1817                 module_put(table_owner);
1818         xt_free_table_info(private);
1819 }
1820 
1821 /* The built-in targets: standard (NULL) and error. */
1822 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1823         {
1824                 .name             = XT_STANDARD_TARGET,
1825                 .targetsize       = sizeof(int),
1826                 .family           = NFPROTO_ARP,
1827 #ifdef CONFIG_COMPAT
1828                 .compatsize       = sizeof(compat_int_t),
1829                 .compat_from_user = compat_standard_from_user,
1830                 .compat_to_user   = compat_standard_to_user,
1831 #endif
1832         },
1833         {
1834                 .name             = XT_ERROR_TARGET,
1835                 .target           = arpt_error,
1836                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1837                 .family           = NFPROTO_ARP,
1838         },
1839 };
1840 
1841 static struct nf_sockopt_ops arpt_sockopts = {
1842         .pf             = PF_INET,
1843         .set_optmin     = ARPT_BASE_CTL,
1844         .set_optmax     = ARPT_SO_SET_MAX+1,
1845         .set            = do_arpt_set_ctl,
1846 #ifdef CONFIG_COMPAT
1847         .compat_set     = compat_do_arpt_set_ctl,
1848 #endif
1849         .get_optmin     = ARPT_BASE_CTL,
1850         .get_optmax     = ARPT_SO_GET_MAX+1,
1851         .get            = do_arpt_get_ctl,
1852 #ifdef CONFIG_COMPAT
1853         .compat_get     = compat_do_arpt_get_ctl,
1854 #endif
1855         .owner          = THIS_MODULE,
1856 };
1857 
1858 static int __net_init arp_tables_net_init(struct net *net)
1859 {
1860         return xt_proto_init(net, NFPROTO_ARP);
1861 }
1862 
1863 static void __net_exit arp_tables_net_exit(struct net *net)
1864 {
1865         xt_proto_fini(net, NFPROTO_ARP);
1866 }
1867 
1868 static struct pernet_operations arp_tables_net_ops = {
1869         .init = arp_tables_net_init,
1870         .exit = arp_tables_net_exit,
1871 };
1872 
1873 static int __init arp_tables_init(void)
1874 {
1875         int ret;
1876 
1877         ret = register_pernet_subsys(&arp_tables_net_ops);
1878         if (ret < 0)
1879                 goto err1;
1880 
1881         /* No one else will be downing sem now, so we won't sleep */
1882         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1883         if (ret < 0)
1884                 goto err2;
1885 
1886         /* Register setsockopt */
1887         ret = nf_register_sockopt(&arpt_sockopts);
1888         if (ret < 0)
1889                 goto err4;
1890 
1891         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1892         return 0;
1893 
1894 err4:
1895         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1896 err2:
1897         unregister_pernet_subsys(&arp_tables_net_ops);
1898 err1:
1899         return ret;
1900 }
1901 
1902 static void __exit arp_tables_fini(void)
1903 {
1904         nf_unregister_sockopt(&arpt_sockopts);
1905         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1906         unregister_pernet_subsys(&arp_tables_net_ops);
1907 }
1908 
1909 EXPORT_SYMBOL(arpt_register_table);
1910 EXPORT_SYMBOL(arpt_unregister_table);
1911 EXPORT_SYMBOL(arpt_do_table);
1912 
1913 module_init(arp_tables_init);
1914 module_exit(arp_tables_fini);
1915 

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