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

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