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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 nf_hook_state *state,
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, **jumpstack;
258         const char *indev, *outdev;
259         const void *table_base;
260         unsigned int cpu, stackidx = 0;
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 = state->in ? state->in->name : nulldevname;
269         outdev = state->out ? state->out->name : nulldevname;
270 
271         local_bh_disable();
272         addend = xt_write_recseq_begin();
273         private = table->private;
274         cpu     = smp_processor_id();
275         /*
276          * Ensure we load private-> members after we've fetched the base
277          * pointer.
278          */
279         smp_read_barrier_depends();
280         table_base = private->entries;
281         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
282 
283         e = get_entry(table_base, private->hook_entry[hook]);
284 
285         acpar.in      = state->in;
286         acpar.out     = state->out;
287         acpar.hooknum = hook;
288         acpar.family  = NFPROTO_ARP;
289         acpar.hotdrop = false;
290 
291         arp = arp_hdr(skb);
292         do {
293                 const struct xt_entry_target *t;
294                 struct xt_counters *counter;
295 
296                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
297                         e = arpt_next_entry(e);
298                         continue;
299                 }
300 
301                 counter = xt_get_this_cpu_counter(&e->counters);
302                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
303 
304                 t = arpt_get_target_c(e);
305 
306                 /* Standard target? */
307                 if (!t->u.kernel.target->target) {
308                         int v;
309 
310                         v = ((struct xt_standard_target *)t)->verdict;
311                         if (v < 0) {
312                                 /* Pop from stack? */
313                                 if (v != XT_RETURN) {
314                                         verdict = (unsigned int)(-v) - 1;
315                                         break;
316                                 }
317                                 if (stackidx == 0) {
318                                         e = get_entry(table_base,
319                                                       private->underflow[hook]);
320                                 } else {
321                                         e = jumpstack[--stackidx];
322                                         e = arpt_next_entry(e);
323                                 }
324                                 continue;
325                         }
326                         if (table_base + v
327                             != arpt_next_entry(e)) {
328 
329                                 if (stackidx >= private->stacksize) {
330                                         verdict = NF_DROP;
331                                         break;
332                                 }
333                                 jumpstack[stackidx++] = e;
334                         }
335 
336                         e = get_entry(table_base, v);
337                         continue;
338                 }
339 
340                 /* Targets which reenter must return
341                  * abs. verdicts
342                  */
343                 acpar.target   = t->u.kernel.target;
344                 acpar.targinfo = t->data;
345                 verdict = t->u.kernel.target->target(skb, &acpar);
346 
347                 /* Target might have changed stuff. */
348                 arp = arp_hdr(skb);
349 
350                 if (verdict == XT_CONTINUE)
351                         e = arpt_next_entry(e);
352                 else
353                         /* Verdict */
354                         break;
355         } while (!acpar.hotdrop);
356         xt_write_recseq_end(addend);
357         local_bh_enable();
358 
359         if (acpar.hotdrop)
360                 return NF_DROP;
361         else
362                 return verdict;
363 }
364 
365 /* All zeroes == unconditional rule. */
366 static inline bool unconditional(const struct arpt_arp *arp)
367 {
368         static const struct arpt_arp uncond;
369 
370         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
371 }
372 
373 /* Figures out from what hook each rule can be called: returns 0 if
374  * there are loops.  Puts hook bitmask in comefrom.
375  */
376 static int mark_source_chains(const struct xt_table_info *newinfo,
377                               unsigned int valid_hooks, void *entry0)
378 {
379         unsigned int hook;
380 
381         /* No recursion; use packet counter to save back ptrs (reset
382          * to 0 as we leave), and comefrom to save source hook bitmask.
383          */
384         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
385                 unsigned int pos = newinfo->hook_entry[hook];
386                 struct arpt_entry *e
387                         = (struct arpt_entry *)(entry0 + pos);
388 
389                 if (!(valid_hooks & (1 << hook)))
390                         continue;
391 
392                 /* Set initial back pointer. */
393                 e->counters.pcnt = pos;
394 
395                 for (;;) {
396                         const struct xt_standard_target *t
397                                 = (void *)arpt_get_target_c(e);
398                         int visited = e->comefrom & (1 << hook);
399 
400                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
401                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
402                                        hook, pos, e->comefrom);
403                                 return 0;
404                         }
405                         e->comefrom
406                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
407 
408                         /* Unconditional return/END. */
409                         if ((e->target_offset == sizeof(struct arpt_entry) &&
410                              (strcmp(t->target.u.user.name,
411                                      XT_STANDARD_TARGET) == 0) &&
412                              t->verdict < 0 && unconditional(&e->arp)) ||
413                             visited) {
414                                 unsigned int oldpos, size;
415 
416                                 if ((strcmp(t->target.u.user.name,
417                                             XT_STANDARD_TARGET) == 0) &&
418                                     t->verdict < -NF_MAX_VERDICT - 1) {
419                                         duprintf("mark_source_chains: bad "
420                                                 "negative verdict (%i)\n",
421                                                                 t->verdict);
422                                         return 0;
423                                 }
424 
425                                 /* Return: backtrack through the last
426                                  * big jump.
427                                  */
428                                 do {
429                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
430                                         oldpos = pos;
431                                         pos = e->counters.pcnt;
432                                         e->counters.pcnt = 0;
433 
434                                         /* We're at the start. */
435                                         if (pos == oldpos)
436                                                 goto next;
437 
438                                         e = (struct arpt_entry *)
439                                                 (entry0 + pos);
440                                 } while (oldpos == pos + e->next_offset);
441 
442                                 /* Move along one */
443                                 size = e->next_offset;
444                                 e = (struct arpt_entry *)
445                                         (entry0 + pos + size);
446                                 e->counters.pcnt = pos;
447                                 pos += size;
448                         } else {
449                                 int newpos = t->verdict;
450 
451                                 if (strcmp(t->target.u.user.name,
452                                            XT_STANDARD_TARGET) == 0 &&
453                                     newpos >= 0) {
454                                         if (newpos > newinfo->size -
455                                                 sizeof(struct arpt_entry)) {
456                                                 duprintf("mark_source_chains: "
457                                                         "bad verdict (%i)\n",
458                                                                 newpos);
459                                                 return 0;
460                                         }
461 
462                                         /* This a jump; chase it. */
463                                         duprintf("Jump rule %u -> %u\n",
464                                                  pos, newpos);
465                                 } else {
466                                         /* ... this is a fallthru */
467                                         newpos = pos + e->next_offset;
468                                 }
469                                 e = (struct arpt_entry *)
470                                         (entry0 + newpos);
471                                 e->counters.pcnt = pos;
472                                 pos = newpos;
473                         }
474                 }
475                 next:
476                 duprintf("Finished chain %u\n", hook);
477         }
478         return 1;
479 }
480 
481 static inline int check_entry(const struct arpt_entry *e, const char *name)
482 {
483         const struct xt_entry_target *t;
484 
485         if (!arp_checkentry(&e->arp)) {
486                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
487                 return -EINVAL;
488         }
489 
490         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
491                 return -EINVAL;
492 
493         t = arpt_get_target_c(e);
494         if (e->target_offset + t->u.target_size > e->next_offset)
495                 return -EINVAL;
496 
497         return 0;
498 }
499 
500 static inline int check_target(struct arpt_entry *e, const char *name)
501 {
502         struct xt_entry_target *t = arpt_get_target(e);
503         int ret;
504         struct xt_tgchk_param par = {
505                 .table     = name,
506                 .entryinfo = e,
507                 .target    = t->u.kernel.target,
508                 .targinfo  = t->data,
509                 .hook_mask = e->comefrom,
510                 .family    = NFPROTO_ARP,
511         };
512 
513         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
514         if (ret < 0) {
515                 duprintf("arp_tables: check failed for `%s'.\n",
516                          t->u.kernel.target->name);
517                 return ret;
518         }
519         return 0;
520 }
521 
522 static inline int
523 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
524 {
525         struct xt_entry_target *t;
526         struct xt_target *target;
527         int ret;
528 
529         ret = check_entry(e, name);
530         if (ret)
531                 return ret;
532 
533         e->counters.pcnt = xt_percpu_counter_alloc();
534         if (IS_ERR_VALUE(e->counters.pcnt))
535                 return -ENOMEM;
536 
537         t = arpt_get_target(e);
538         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
539                                         t->u.user.revision);
540         if (IS_ERR(target)) {
541                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
542                 ret = PTR_ERR(target);
543                 goto out;
544         }
545         t->u.kernel.target = target;
546 
547         ret = check_target(e, name);
548         if (ret)
549                 goto err;
550         return 0;
551 err:
552         module_put(t->u.kernel.target->me);
553 out:
554         xt_percpu_counter_free(e->counters.pcnt);
555 
556         return ret;
557 }
558 
559 static bool check_underflow(const struct arpt_entry *e)
560 {
561         const struct xt_entry_target *t;
562         unsigned int verdict;
563 
564         if (!unconditional(&e->arp))
565                 return false;
566         t = arpt_get_target_c(e);
567         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
568                 return false;
569         verdict = ((struct xt_standard_target *)t)->verdict;
570         verdict = -verdict - 1;
571         return verdict == NF_DROP || verdict == NF_ACCEPT;
572 }
573 
574 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
575                                              struct xt_table_info *newinfo,
576                                              const unsigned char *base,
577                                              const unsigned char *limit,
578                                              const unsigned int *hook_entries,
579                                              const unsigned int *underflows,
580                                              unsigned int valid_hooks)
581 {
582         unsigned int h;
583 
584         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
585             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
586                 duprintf("Bad offset %p\n", e);
587                 return -EINVAL;
588         }
589 
590         if (e->next_offset
591             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
592                 duprintf("checking: element %p size %u\n",
593                          e, e->next_offset);
594                 return -EINVAL;
595         }
596 
597         /* Check hooks & underflows */
598         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
599                 if (!(valid_hooks & (1 << h)))
600                         continue;
601                 if ((unsigned char *)e - base == hook_entries[h])
602                         newinfo->hook_entry[h] = hook_entries[h];
603                 if ((unsigned char *)e - base == underflows[h]) {
604                         if (!check_underflow(e)) {
605                                 pr_err("Underflows must be unconditional and "
606                                        "use the STANDARD target with "
607                                        "ACCEPT/DROP\n");
608                                 return -EINVAL;
609                         }
610                         newinfo->underflow[h] = underflows[h];
611                 }
612         }
613 
614         /* Clear counters and comefrom */
615         e->counters = ((struct xt_counters) { 0, 0 });
616         e->comefrom = 0;
617         return 0;
618 }
619 
620 static inline void cleanup_entry(struct arpt_entry *e)
621 {
622         struct xt_tgdtor_param par;
623         struct xt_entry_target *t;
624 
625         t = arpt_get_target(e);
626         par.target   = t->u.kernel.target;
627         par.targinfo = t->data;
628         par.family   = NFPROTO_ARP;
629         if (par.target->destroy != NULL)
630                 par.target->destroy(&par);
631         module_put(par.target->me);
632         xt_percpu_counter_free(e->counters.pcnt);
633 }
634 
635 /* Checks and translates the user-supplied table segment (held in
636  * newinfo).
637  */
638 static int translate_table(struct xt_table_info *newinfo, void *entry0,
639                            const struct arpt_replace *repl)
640 {
641         struct arpt_entry *iter;
642         unsigned int i;
643         int ret = 0;
644 
645         newinfo->size = repl->size;
646         newinfo->number = repl->num_entries;
647 
648         /* Init all hooks to impossible value. */
649         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
650                 newinfo->hook_entry[i] = 0xFFFFFFFF;
651                 newinfo->underflow[i] = 0xFFFFFFFF;
652         }
653 
654         duprintf("translate_table: size %u\n", newinfo->size);
655         i = 0;
656 
657         /* Walk through entries, checking offsets. */
658         xt_entry_foreach(iter, entry0, newinfo->size) {
659                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
660                                                  entry0 + repl->size,
661                                                  repl->hook_entry,
662                                                  repl->underflow,
663                                                  repl->valid_hooks);
664                 if (ret != 0)
665                         break;
666                 ++i;
667                 if (strcmp(arpt_get_target(iter)->u.user.name,
668                     XT_ERROR_TARGET) == 0)
669                         ++newinfo->stacksize;
670         }
671         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
672         if (ret != 0)
673                 return ret;
674 
675         if (i != repl->num_entries) {
676                 duprintf("translate_table: %u not %u entries\n",
677                          i, repl->num_entries);
678                 return -EINVAL;
679         }
680 
681         /* Check hooks all assigned */
682         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
683                 /* Only hooks which are valid */
684                 if (!(repl->valid_hooks & (1 << i)))
685                         continue;
686                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
687                         duprintf("Invalid hook entry %u %u\n",
688                                  i, repl->hook_entry[i]);
689                         return -EINVAL;
690                 }
691                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
692                         duprintf("Invalid underflow %u %u\n",
693                                  i, repl->underflow[i]);
694                         return -EINVAL;
695                 }
696         }
697 
698         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
699                 duprintf("Looping hook\n");
700                 return -ELOOP;
701         }
702 
703         /* Finally, each sanity check must pass */
704         i = 0;
705         xt_entry_foreach(iter, entry0, newinfo->size) {
706                 ret = find_check_entry(iter, repl->name, repl->size);
707                 if (ret != 0)
708                         break;
709                 ++i;
710         }
711 
712         if (ret != 0) {
713                 xt_entry_foreach(iter, entry0, newinfo->size) {
714                         if (i-- == 0)
715                                 break;
716                         cleanup_entry(iter);
717                 }
718                 return ret;
719         }
720 
721         return ret;
722 }
723 
724 static void get_counters(const struct xt_table_info *t,
725                          struct xt_counters counters[])
726 {
727         struct arpt_entry *iter;
728         unsigned int cpu;
729         unsigned int i;
730 
731         for_each_possible_cpu(cpu) {
732                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
733 
734                 i = 0;
735                 xt_entry_foreach(iter, t->entries, t->size) {
736                         struct xt_counters *tmp;
737                         u64 bcnt, pcnt;
738                         unsigned int start;
739 
740                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
741                         do {
742                                 start = read_seqcount_begin(s);
743                                 bcnt = tmp->bcnt;
744                                 pcnt = tmp->pcnt;
745                         } while (read_seqcount_retry(s, start));
746 
747                         ADD_COUNTER(counters[i], bcnt, pcnt);
748                         ++i;
749                 }
750         }
751 }
752 
753 static struct xt_counters *alloc_counters(const struct xt_table *table)
754 {
755         unsigned int countersize;
756         struct xt_counters *counters;
757         const struct xt_table_info *private = table->private;
758 
759         /* We need atomic snapshot of counters: rest doesn't change
760          * (other than comefrom, which userspace doesn't care
761          * about).
762          */
763         countersize = sizeof(struct xt_counters) * private->number;
764         counters = vzalloc(countersize);
765 
766         if (counters == NULL)
767                 return ERR_PTR(-ENOMEM);
768 
769         get_counters(private, counters);
770 
771         return counters;
772 }
773 
774 static int copy_entries_to_user(unsigned int total_size,
775                                 const struct xt_table *table,
776                                 void __user *userptr)
777 {
778         unsigned int off, num;
779         const struct arpt_entry *e;
780         struct xt_counters *counters;
781         struct xt_table_info *private = table->private;
782         int ret = 0;
783         void *loc_cpu_entry;
784 
785         counters = alloc_counters(table);
786         if (IS_ERR(counters))
787                 return PTR_ERR(counters);
788 
789         loc_cpu_entry = private->entries;
790         /* ... then copy entire thing ... */
791         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
792                 ret = -EFAULT;
793                 goto free_counters;
794         }
795 
796         /* FIXME: use iterator macros --RR */
797         /* ... then go back and fix counters and names */
798         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
799                 const struct xt_entry_target *t;
800 
801                 e = (struct arpt_entry *)(loc_cpu_entry + off);
802                 if (copy_to_user(userptr + off
803                                  + offsetof(struct arpt_entry, counters),
804                                  &counters[num],
805                                  sizeof(counters[num])) != 0) {
806                         ret = -EFAULT;
807                         goto free_counters;
808                 }
809 
810                 t = arpt_get_target_c(e);
811                 if (copy_to_user(userptr + off + e->target_offset
812                                  + offsetof(struct xt_entry_target,
813                                             u.user.name),
814                                  t->u.kernel.target->name,
815                                  strlen(t->u.kernel.target->name)+1) != 0) {
816                         ret = -EFAULT;
817                         goto free_counters;
818                 }
819         }
820 
821  free_counters:
822         vfree(counters);
823         return ret;
824 }
825 
826 #ifdef CONFIG_COMPAT
827 static void compat_standard_from_user(void *dst, const void *src)
828 {
829         int v = *(compat_int_t *)src;
830 
831         if (v > 0)
832                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
833         memcpy(dst, &v, sizeof(v));
834 }
835 
836 static int compat_standard_to_user(void __user *dst, const void *src)
837 {
838         compat_int_t cv = *(int *)src;
839 
840         if (cv > 0)
841                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
842         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
843 }
844 
845 static int compat_calc_entry(const struct arpt_entry *e,
846                              const struct xt_table_info *info,
847                              const void *base, struct xt_table_info *newinfo)
848 {
849         const struct xt_entry_target *t;
850         unsigned int entry_offset;
851         int off, i, ret;
852 
853         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
854         entry_offset = (void *)e - base;
855 
856         t = arpt_get_target_c(e);
857         off += xt_compat_target_offset(t->u.kernel.target);
858         newinfo->size -= off;
859         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
860         if (ret)
861                 return ret;
862 
863         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
864                 if (info->hook_entry[i] &&
865                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
866                         newinfo->hook_entry[i] -= off;
867                 if (info->underflow[i] &&
868                     (e < (struct arpt_entry *)(base + info->underflow[i])))
869                         newinfo->underflow[i] -= off;
870         }
871         return 0;
872 }
873 
874 static int compat_table_info(const struct xt_table_info *info,
875                              struct xt_table_info *newinfo)
876 {
877         struct arpt_entry *iter;
878         const void *loc_cpu_entry;
879         int ret;
880 
881         if (!newinfo || !info)
882                 return -EINVAL;
883 
884         /* we dont care about newinfo->entries */
885         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
886         newinfo->initial_entries = 0;
887         loc_cpu_entry = info->entries;
888         xt_compat_init_offsets(NFPROTO_ARP, info->number);
889         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
890                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
891                 if (ret != 0)
892                         return ret;
893         }
894         return 0;
895 }
896 #endif
897 
898 static int get_info(struct net *net, void __user *user,
899                     const int *len, int compat)
900 {
901         char name[XT_TABLE_MAXNAMELEN];
902         struct xt_table *t;
903         int ret;
904 
905         if (*len != sizeof(struct arpt_getinfo)) {
906                 duprintf("length %u != %Zu\n", *len,
907                          sizeof(struct arpt_getinfo));
908                 return -EINVAL;
909         }
910 
911         if (copy_from_user(name, user, sizeof(name)) != 0)
912                 return -EFAULT;
913 
914         name[XT_TABLE_MAXNAMELEN-1] = '\0';
915 #ifdef CONFIG_COMPAT
916         if (compat)
917                 xt_compat_lock(NFPROTO_ARP);
918 #endif
919         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
920                                     "arptable_%s", name);
921         if (!IS_ERR_OR_NULL(t)) {
922                 struct arpt_getinfo info;
923                 const struct xt_table_info *private = t->private;
924 #ifdef CONFIG_COMPAT
925                 struct xt_table_info tmp;
926 
927                 if (compat) {
928                         ret = compat_table_info(private, &tmp);
929                         xt_compat_flush_offsets(NFPROTO_ARP);
930                         private = &tmp;
931                 }
932 #endif
933                 memset(&info, 0, sizeof(info));
934                 info.valid_hooks = t->valid_hooks;
935                 memcpy(info.hook_entry, private->hook_entry,
936                        sizeof(info.hook_entry));
937                 memcpy(info.underflow, private->underflow,
938                        sizeof(info.underflow));
939                 info.num_entries = private->number;
940                 info.size = private->size;
941                 strcpy(info.name, name);
942 
943                 if (copy_to_user(user, &info, *len) != 0)
944                         ret = -EFAULT;
945                 else
946                         ret = 0;
947                 xt_table_unlock(t);
948                 module_put(t->me);
949         } else
950                 ret = t ? PTR_ERR(t) : -ENOENT;
951 #ifdef CONFIG_COMPAT
952         if (compat)
953                 xt_compat_unlock(NFPROTO_ARP);
954 #endif
955         return ret;
956 }
957 
958 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
959                        const int *len)
960 {
961         int ret;
962         struct arpt_get_entries get;
963         struct xt_table *t;
964 
965         if (*len < sizeof(get)) {
966                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
967                 return -EINVAL;
968         }
969         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
970                 return -EFAULT;
971         if (*len != sizeof(struct arpt_get_entries) + get.size) {
972                 duprintf("get_entries: %u != %Zu\n", *len,
973                          sizeof(struct arpt_get_entries) + get.size);
974                 return -EINVAL;
975         }
976 
977         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
978         if (!IS_ERR_OR_NULL(t)) {
979                 const struct xt_table_info *private = t->private;
980 
981                 duprintf("t->private->number = %u\n",
982                          private->number);
983                 if (get.size == private->size)
984                         ret = copy_entries_to_user(private->size,
985                                                    t, uptr->entrytable);
986                 else {
987                         duprintf("get_entries: I've got %u not %u!\n",
988                                  private->size, get.size);
989                         ret = -EAGAIN;
990                 }
991                 module_put(t->me);
992                 xt_table_unlock(t);
993         } else
994                 ret = t ? PTR_ERR(t) : -ENOENT;
995 
996         return ret;
997 }
998 
999 static int __do_replace(struct net *net, const char *name,
1000                         unsigned int valid_hooks,
1001                         struct xt_table_info *newinfo,
1002                         unsigned int num_counters,
1003                         void __user *counters_ptr)
1004 {
1005         int ret;
1006         struct xt_table *t;
1007         struct xt_table_info *oldinfo;
1008         struct xt_counters *counters;
1009         void *loc_cpu_old_entry;
1010         struct arpt_entry *iter;
1011 
1012         ret = 0;
1013         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1014         if (!counters) {
1015                 ret = -ENOMEM;
1016                 goto out;
1017         }
1018 
1019         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1020                                     "arptable_%s", name);
1021         if (IS_ERR_OR_NULL(t)) {
1022                 ret = t ? PTR_ERR(t) : -ENOENT;
1023                 goto free_newinfo_counters_untrans;
1024         }
1025 
1026         /* You lied! */
1027         if (valid_hooks != t->valid_hooks) {
1028                 duprintf("Valid hook crap: %08X vs %08X\n",
1029                          valid_hooks, t->valid_hooks);
1030                 ret = -EINVAL;
1031                 goto put_module;
1032         }
1033 
1034         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1035         if (!oldinfo)
1036                 goto put_module;
1037 
1038         /* Update module usage count based on number of rules */
1039         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1040                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1041         if ((oldinfo->number > oldinfo->initial_entries) ||
1042             (newinfo->number <= oldinfo->initial_entries))
1043                 module_put(t->me);
1044         if ((oldinfo->number > oldinfo->initial_entries) &&
1045             (newinfo->number <= oldinfo->initial_entries))
1046                 module_put(t->me);
1047 
1048         /* Get the old counters, and synchronize with replace */
1049         get_counters(oldinfo, counters);
1050 
1051         /* Decrease module usage counts and free resource */
1052         loc_cpu_old_entry = oldinfo->entries;
1053         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1054                 cleanup_entry(iter);
1055 
1056         xt_free_table_info(oldinfo);
1057         if (copy_to_user(counters_ptr, counters,
1058                          sizeof(struct xt_counters) * num_counters) != 0) {
1059                 /* Silent error, can't fail, new table is already in place */
1060                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1061         }
1062         vfree(counters);
1063         xt_table_unlock(t);
1064         return ret;
1065 
1066  put_module:
1067         module_put(t->me);
1068         xt_table_unlock(t);
1069  free_newinfo_counters_untrans:
1070         vfree(counters);
1071  out:
1072         return ret;
1073 }
1074 
1075 static int do_replace(struct net *net, const void __user *user,
1076                       unsigned int len)
1077 {
1078         int ret;
1079         struct arpt_replace tmp;
1080         struct xt_table_info *newinfo;
1081         void *loc_cpu_entry;
1082         struct arpt_entry *iter;
1083 
1084         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1085                 return -EFAULT;
1086 
1087         /* overflow check */
1088         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1089                 return -ENOMEM;
1090         if (tmp.num_counters == 0)
1091                 return -EINVAL;
1092 
1093         tmp.name[sizeof(tmp.name)-1] = 0;
1094 
1095         newinfo = xt_alloc_table_info(tmp.size);
1096         if (!newinfo)
1097                 return -ENOMEM;
1098 
1099         loc_cpu_entry = newinfo->entries;
1100         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1101                            tmp.size) != 0) {
1102                 ret = -EFAULT;
1103                 goto free_newinfo;
1104         }
1105 
1106         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1107         if (ret != 0)
1108                 goto free_newinfo;
1109 
1110         duprintf("arp_tables: Translated table\n");
1111 
1112         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1113                            tmp.num_counters, tmp.counters);
1114         if (ret)
1115                 goto free_newinfo_untrans;
1116         return 0;
1117 
1118  free_newinfo_untrans:
1119         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1120                 cleanup_entry(iter);
1121  free_newinfo:
1122         xt_free_table_info(newinfo);
1123         return ret;
1124 }
1125 
1126 static int do_add_counters(struct net *net, const void __user *user,
1127                            unsigned int len, int compat)
1128 {
1129         unsigned int i;
1130         struct xt_counters_info tmp;
1131         struct xt_counters *paddc;
1132         unsigned int num_counters;
1133         const char *name;
1134         int size;
1135         void *ptmp;
1136         struct xt_table *t;
1137         const struct xt_table_info *private;
1138         int ret = 0;
1139         struct arpt_entry *iter;
1140         unsigned int addend;
1141 #ifdef CONFIG_COMPAT
1142         struct compat_xt_counters_info compat_tmp;
1143 
1144         if (compat) {
1145                 ptmp = &compat_tmp;
1146                 size = sizeof(struct compat_xt_counters_info);
1147         } else
1148 #endif
1149         {
1150                 ptmp = &tmp;
1151                 size = sizeof(struct xt_counters_info);
1152         }
1153 
1154         if (copy_from_user(ptmp, user, size) != 0)
1155                 return -EFAULT;
1156 
1157 #ifdef CONFIG_COMPAT
1158         if (compat) {
1159                 num_counters = compat_tmp.num_counters;
1160                 name = compat_tmp.name;
1161         } else
1162 #endif
1163         {
1164                 num_counters = tmp.num_counters;
1165                 name = tmp.name;
1166         }
1167 
1168         if (len != size + num_counters * sizeof(struct xt_counters))
1169                 return -EINVAL;
1170 
1171         paddc = vmalloc(len - size);
1172         if (!paddc)
1173                 return -ENOMEM;
1174 
1175         if (copy_from_user(paddc, user + size, len - size) != 0) {
1176                 ret = -EFAULT;
1177                 goto free;
1178         }
1179 
1180         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1181         if (IS_ERR_OR_NULL(t)) {
1182                 ret = t ? PTR_ERR(t) : -ENOENT;
1183                 goto free;
1184         }
1185 
1186         local_bh_disable();
1187         private = t->private;
1188         if (private->number != num_counters) {
1189                 ret = -EINVAL;
1190                 goto unlock_up_free;
1191         }
1192 
1193         i = 0;
1194 
1195         addend = xt_write_recseq_begin();
1196         xt_entry_foreach(iter,  private->entries, private->size) {
1197                 struct xt_counters *tmp;
1198 
1199                 tmp = xt_get_this_cpu_counter(&iter->counters);
1200                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1201                 ++i;
1202         }
1203         xt_write_recseq_end(addend);
1204  unlock_up_free:
1205         local_bh_enable();
1206         xt_table_unlock(t);
1207         module_put(t->me);
1208  free:
1209         vfree(paddc);
1210 
1211         return ret;
1212 }
1213 
1214 #ifdef CONFIG_COMPAT
1215 static inline void compat_release_entry(struct compat_arpt_entry *e)
1216 {
1217         struct xt_entry_target *t;
1218 
1219         t = compat_arpt_get_target(e);
1220         module_put(t->u.kernel.target->me);
1221 }
1222 
1223 static inline int
1224 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1225                                   struct xt_table_info *newinfo,
1226                                   unsigned int *size,
1227                                   const unsigned char *base,
1228                                   const unsigned char *limit,
1229                                   const unsigned int *hook_entries,
1230                                   const unsigned int *underflows,
1231                                   const char *name)
1232 {
1233         struct xt_entry_target *t;
1234         struct xt_target *target;
1235         unsigned int entry_offset;
1236         int ret, off, h;
1237 
1238         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1239         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1240             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1241                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1242                 return -EINVAL;
1243         }
1244 
1245         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1246                              sizeof(struct compat_xt_entry_target)) {
1247                 duprintf("checking: element %p size %u\n",
1248                          e, e->next_offset);
1249                 return -EINVAL;
1250         }
1251 
1252         /* For purposes of check_entry casting the compat entry is fine */
1253         ret = check_entry((struct arpt_entry *)e, name);
1254         if (ret)
1255                 return ret;
1256 
1257         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1258         entry_offset = (void *)e - (void *)base;
1259 
1260         t = compat_arpt_get_target(e);
1261         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1262                                         t->u.user.revision);
1263         if (IS_ERR(target)) {
1264                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1265                          t->u.user.name);
1266                 ret = PTR_ERR(target);
1267                 goto out;
1268         }
1269         t->u.kernel.target = target;
1270 
1271         off += xt_compat_target_offset(target);
1272         *size += off;
1273         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1274         if (ret)
1275                 goto release_target;
1276 
1277         /* Check hooks & underflows */
1278         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1279                 if ((unsigned char *)e - base == hook_entries[h])
1280                         newinfo->hook_entry[h] = hook_entries[h];
1281                 if ((unsigned char *)e - base == underflows[h])
1282                         newinfo->underflow[h] = underflows[h];
1283         }
1284 
1285         /* Clear counters and comefrom */
1286         memset(&e->counters, 0, sizeof(e->counters));
1287         e->comefrom = 0;
1288         return 0;
1289 
1290 release_target:
1291         module_put(t->u.kernel.target->me);
1292 out:
1293         return ret;
1294 }
1295 
1296 static int
1297 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1298                             unsigned int *size, const char *name,
1299                             struct xt_table_info *newinfo, unsigned char *base)
1300 {
1301         struct xt_entry_target *t;
1302         struct xt_target *target;
1303         struct arpt_entry *de;
1304         unsigned int origsize;
1305         int ret, h;
1306 
1307         ret = 0;
1308         origsize = *size;
1309         de = (struct arpt_entry *)*dstptr;
1310         memcpy(de, e, sizeof(struct arpt_entry));
1311         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1312 
1313         *dstptr += sizeof(struct arpt_entry);
1314         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1315 
1316         de->target_offset = e->target_offset - (origsize - *size);
1317         t = compat_arpt_get_target(e);
1318         target = t->u.kernel.target;
1319         xt_compat_target_from_user(t, dstptr, size);
1320 
1321         de->next_offset = e->next_offset - (origsize - *size);
1322         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1323                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1324                         newinfo->hook_entry[h] -= origsize - *size;
1325                 if ((unsigned char *)de - base < newinfo->underflow[h])
1326                         newinfo->underflow[h] -= origsize - *size;
1327         }
1328         return ret;
1329 }
1330 
1331 static int translate_compat_table(const char *name,
1332                                   unsigned int valid_hooks,
1333                                   struct xt_table_info **pinfo,
1334                                   void **pentry0,
1335                                   unsigned int total_size,
1336                                   unsigned int number,
1337                                   unsigned int *hook_entries,
1338                                   unsigned int *underflows)
1339 {
1340         unsigned int i, j;
1341         struct xt_table_info *newinfo, *info;
1342         void *pos, *entry0, *entry1;
1343         struct compat_arpt_entry *iter0;
1344         struct arpt_entry *iter1;
1345         unsigned int size;
1346         int ret = 0;
1347 
1348         info = *pinfo;
1349         entry0 = *pentry0;
1350         size = total_size;
1351         info->number = number;
1352 
1353         /* Init all hooks to impossible value. */
1354         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1355                 info->hook_entry[i] = 0xFFFFFFFF;
1356                 info->underflow[i] = 0xFFFFFFFF;
1357         }
1358 
1359         duprintf("translate_compat_table: size %u\n", info->size);
1360         j = 0;
1361         xt_compat_lock(NFPROTO_ARP);
1362         xt_compat_init_offsets(NFPROTO_ARP, number);
1363         /* Walk through entries, checking offsets. */
1364         xt_entry_foreach(iter0, entry0, total_size) {
1365                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1366                                                         entry0,
1367                                                         entry0 + total_size,
1368                                                         hook_entries,
1369                                                         underflows,
1370                                                         name);
1371                 if (ret != 0)
1372                         goto out_unlock;
1373                 ++j;
1374         }
1375 
1376         ret = -EINVAL;
1377         if (j != number) {
1378                 duprintf("translate_compat_table: %u not %u entries\n",
1379                          j, number);
1380                 goto out_unlock;
1381         }
1382 
1383         /* Check hooks all assigned */
1384         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1385                 /* Only hooks which are valid */
1386                 if (!(valid_hooks & (1 << i)))
1387                         continue;
1388                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1389                         duprintf("Invalid hook entry %u %u\n",
1390                                  i, hook_entries[i]);
1391                         goto out_unlock;
1392                 }
1393                 if (info->underflow[i] == 0xFFFFFFFF) {
1394                         duprintf("Invalid underflow %u %u\n",
1395                                  i, underflows[i]);
1396                         goto out_unlock;
1397                 }
1398         }
1399 
1400         ret = -ENOMEM;
1401         newinfo = xt_alloc_table_info(size);
1402         if (!newinfo)
1403                 goto out_unlock;
1404 
1405         newinfo->number = number;
1406         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1407                 newinfo->hook_entry[i] = info->hook_entry[i];
1408                 newinfo->underflow[i] = info->underflow[i];
1409         }
1410         entry1 = newinfo->entries;
1411         pos = entry1;
1412         size = total_size;
1413         xt_entry_foreach(iter0, entry0, total_size) {
1414                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1415                                                   name, newinfo, entry1);
1416                 if (ret != 0)
1417                         break;
1418         }
1419         xt_compat_flush_offsets(NFPROTO_ARP);
1420         xt_compat_unlock(NFPROTO_ARP);
1421         if (ret)
1422                 goto free_newinfo;
1423 
1424         ret = -ELOOP;
1425         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1426                 goto free_newinfo;
1427 
1428         i = 0;
1429         xt_entry_foreach(iter1, entry1, newinfo->size) {
1430                 iter1->counters.pcnt = xt_percpu_counter_alloc();
1431                 if (IS_ERR_VALUE(iter1->counters.pcnt)) {
1432                         ret = -ENOMEM;
1433                         break;
1434                 }
1435 
1436                 ret = check_target(iter1, name);
1437                 if (ret != 0) {
1438                         xt_percpu_counter_free(iter1->counters.pcnt);
1439                         break;
1440                 }
1441                 ++i;
1442                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1443                     XT_ERROR_TARGET) == 0)
1444                         ++newinfo->stacksize;
1445         }
1446         if (ret) {
1447                 /*
1448                  * The first i matches need cleanup_entry (calls ->destroy)
1449                  * because they had called ->check already. The other j-i
1450                  * entries need only release.
1451                  */
1452                 int skip = i;
1453                 j -= i;
1454                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1455                         if (skip-- > 0)
1456                                 continue;
1457                         if (j-- == 0)
1458                                 break;
1459                         compat_release_entry(iter0);
1460                 }
1461                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1462                         if (i-- == 0)
1463                                 break;
1464                         cleanup_entry(iter1);
1465                 }
1466                 xt_free_table_info(newinfo);
1467                 return ret;
1468         }
1469 
1470         *pinfo = newinfo;
1471         *pentry0 = entry1;
1472         xt_free_table_info(info);
1473         return 0;
1474 
1475 free_newinfo:
1476         xt_free_table_info(newinfo);
1477 out:
1478         xt_entry_foreach(iter0, entry0, total_size) {
1479                 if (j-- == 0)
1480                         break;
1481                 compat_release_entry(iter0);
1482         }
1483         return ret;
1484 out_unlock:
1485         xt_compat_flush_offsets(NFPROTO_ARP);
1486         xt_compat_unlock(NFPROTO_ARP);
1487         goto out;
1488 }
1489 
1490 struct compat_arpt_replace {
1491         char                            name[XT_TABLE_MAXNAMELEN];
1492         u32                             valid_hooks;
1493         u32                             num_entries;
1494         u32                             size;
1495         u32                             hook_entry[NF_ARP_NUMHOOKS];
1496         u32                             underflow[NF_ARP_NUMHOOKS];
1497         u32                             num_counters;
1498         compat_uptr_t                   counters;
1499         struct compat_arpt_entry        entries[0];
1500 };
1501 
1502 static int compat_do_replace(struct net *net, void __user *user,
1503                              unsigned int len)
1504 {
1505         int ret;
1506         struct compat_arpt_replace tmp;
1507         struct xt_table_info *newinfo;
1508         void *loc_cpu_entry;
1509         struct arpt_entry *iter;
1510 
1511         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1512                 return -EFAULT;
1513 
1514         /* overflow check */
1515         if (tmp.size >= INT_MAX / num_possible_cpus())
1516                 return -ENOMEM;
1517         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1518                 return -ENOMEM;
1519         if (tmp.num_counters == 0)
1520                 return -EINVAL;
1521 
1522         tmp.name[sizeof(tmp.name)-1] = 0;
1523 
1524         newinfo = xt_alloc_table_info(tmp.size);
1525         if (!newinfo)
1526                 return -ENOMEM;
1527 
1528         loc_cpu_entry = newinfo->entries;
1529         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1530                 ret = -EFAULT;
1531                 goto free_newinfo;
1532         }
1533 
1534         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1535                                      &newinfo, &loc_cpu_entry, tmp.size,
1536                                      tmp.num_entries, tmp.hook_entry,
1537                                      tmp.underflow);
1538         if (ret != 0)
1539                 goto free_newinfo;
1540 
1541         duprintf("compat_do_replace: Translated table\n");
1542 
1543         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1544                            tmp.num_counters, compat_ptr(tmp.counters));
1545         if (ret)
1546                 goto free_newinfo_untrans;
1547         return 0;
1548 
1549  free_newinfo_untrans:
1550         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1551                 cleanup_entry(iter);
1552  free_newinfo:
1553         xt_free_table_info(newinfo);
1554         return ret;
1555 }
1556 
1557 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1558                                   unsigned int len)
1559 {
1560         int ret;
1561 
1562         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1563                 return -EPERM;
1564 
1565         switch (cmd) {
1566         case ARPT_SO_SET_REPLACE:
1567                 ret = compat_do_replace(sock_net(sk), user, len);
1568                 break;
1569 
1570         case ARPT_SO_SET_ADD_COUNTERS:
1571                 ret = do_add_counters(sock_net(sk), user, len, 1);
1572                 break;
1573 
1574         default:
1575                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1576                 ret = -EINVAL;
1577         }
1578 
1579         return ret;
1580 }
1581 
1582 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1583                                      compat_uint_t *size,
1584                                      struct xt_counters *counters,
1585                                      unsigned int i)
1586 {
1587         struct xt_entry_target *t;
1588         struct compat_arpt_entry __user *ce;
1589         u_int16_t target_offset, next_offset;
1590         compat_uint_t origsize;
1591         int ret;
1592 
1593         origsize = *size;
1594         ce = (struct compat_arpt_entry __user *)*dstptr;
1595         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1596             copy_to_user(&ce->counters, &counters[i],
1597             sizeof(counters[i])) != 0)
1598                 return -EFAULT;
1599 
1600         *dstptr += sizeof(struct compat_arpt_entry);
1601         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1602 
1603         target_offset = e->target_offset - (origsize - *size);
1604 
1605         t = arpt_get_target(e);
1606         ret = xt_compat_target_to_user(t, dstptr, size);
1607         if (ret)
1608                 return ret;
1609         next_offset = e->next_offset - (origsize - *size);
1610         if (put_user(target_offset, &ce->target_offset) != 0 ||
1611             put_user(next_offset, &ce->next_offset) != 0)
1612                 return -EFAULT;
1613         return 0;
1614 }
1615 
1616 static int compat_copy_entries_to_user(unsigned int total_size,
1617                                        struct xt_table *table,
1618                                        void __user *userptr)
1619 {
1620         struct xt_counters *counters;
1621         const struct xt_table_info *private = table->private;
1622         void __user *pos;
1623         unsigned int size;
1624         int ret = 0;
1625         unsigned int i = 0;
1626         struct arpt_entry *iter;
1627 
1628         counters = alloc_counters(table);
1629         if (IS_ERR(counters))
1630                 return PTR_ERR(counters);
1631 
1632         pos = userptr;
1633         size = total_size;
1634         xt_entry_foreach(iter, private->entries, total_size) {
1635                 ret = compat_copy_entry_to_user(iter, &pos,
1636                                                 &size, counters, i++);
1637                 if (ret != 0)
1638                         break;
1639         }
1640         vfree(counters);
1641         return ret;
1642 }
1643 
1644 struct compat_arpt_get_entries {
1645         char name[XT_TABLE_MAXNAMELEN];
1646         compat_uint_t size;
1647         struct compat_arpt_entry entrytable[0];
1648 };
1649 
1650 static int compat_get_entries(struct net *net,
1651                               struct compat_arpt_get_entries __user *uptr,
1652                               int *len)
1653 {
1654         int ret;
1655         struct compat_arpt_get_entries get;
1656         struct xt_table *t;
1657 
1658         if (*len < sizeof(get)) {
1659                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1660                 return -EINVAL;
1661         }
1662         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1663                 return -EFAULT;
1664         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1665                 duprintf("compat_get_entries: %u != %zu\n",
1666                          *len, sizeof(get) + get.size);
1667                 return -EINVAL;
1668         }
1669 
1670         xt_compat_lock(NFPROTO_ARP);
1671         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1672         if (!IS_ERR_OR_NULL(t)) {
1673                 const struct xt_table_info *private = t->private;
1674                 struct xt_table_info info;
1675 
1676                 duprintf("t->private->number = %u\n", private->number);
1677                 ret = compat_table_info(private, &info);
1678                 if (!ret && get.size == info.size) {
1679                         ret = compat_copy_entries_to_user(private->size,
1680                                                           t, uptr->entrytable);
1681                 } else if (!ret) {
1682                         duprintf("compat_get_entries: I've got %u not %u!\n",
1683                                  private->size, get.size);
1684                         ret = -EAGAIN;
1685                 }
1686                 xt_compat_flush_offsets(NFPROTO_ARP);
1687                 module_put(t->me);
1688                 xt_table_unlock(t);
1689         } else
1690                 ret = t ? PTR_ERR(t) : -ENOENT;
1691 
1692         xt_compat_unlock(NFPROTO_ARP);
1693         return ret;
1694 }
1695 
1696 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1697 
1698 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1699                                   int *len)
1700 {
1701         int ret;
1702 
1703         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1704                 return -EPERM;
1705 
1706         switch (cmd) {
1707         case ARPT_SO_GET_INFO:
1708                 ret = get_info(sock_net(sk), user, len, 1);
1709                 break;
1710         case ARPT_SO_GET_ENTRIES:
1711                 ret = compat_get_entries(sock_net(sk), user, len);
1712                 break;
1713         default:
1714                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1715         }
1716         return ret;
1717 }
1718 #endif
1719 
1720 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1721 {
1722         int ret;
1723 
1724         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1725                 return -EPERM;
1726 
1727         switch (cmd) {
1728         case ARPT_SO_SET_REPLACE:
1729                 ret = do_replace(sock_net(sk), user, len);
1730                 break;
1731 
1732         case ARPT_SO_SET_ADD_COUNTERS:
1733                 ret = do_add_counters(sock_net(sk), user, len, 0);
1734                 break;
1735 
1736         default:
1737                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1738                 ret = -EINVAL;
1739         }
1740 
1741         return ret;
1742 }
1743 
1744 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1745 {
1746         int ret;
1747 
1748         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1749                 return -EPERM;
1750 
1751         switch (cmd) {
1752         case ARPT_SO_GET_INFO:
1753                 ret = get_info(sock_net(sk), user, len, 0);
1754                 break;
1755 
1756         case ARPT_SO_GET_ENTRIES:
1757                 ret = get_entries(sock_net(sk), user, len);
1758                 break;
1759 
1760         case ARPT_SO_GET_REVISION_TARGET: {
1761                 struct xt_get_revision rev;
1762 
1763                 if (*len != sizeof(rev)) {
1764                         ret = -EINVAL;
1765                         break;
1766                 }
1767                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1768                         ret = -EFAULT;
1769                         break;
1770                 }
1771                 rev.name[sizeof(rev.name)-1] = 0;
1772 
1773                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1774                                                          rev.revision, 1, &ret),
1775                                         "arpt_%s", rev.name);
1776                 break;
1777         }
1778 
1779         default:
1780                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1781                 ret = -EINVAL;
1782         }
1783 
1784         return ret;
1785 }
1786 
1787 struct xt_table *arpt_register_table(struct net *net,
1788                                      const struct xt_table *table,
1789                                      const struct arpt_replace *repl)
1790 {
1791         int ret;
1792         struct xt_table_info *newinfo;
1793         struct xt_table_info bootstrap = {0};
1794         void *loc_cpu_entry;
1795         struct xt_table *new_table;
1796 
1797         newinfo = xt_alloc_table_info(repl->size);
1798         if (!newinfo) {
1799                 ret = -ENOMEM;
1800                 goto out;
1801         }
1802 
1803         loc_cpu_entry = newinfo->entries;
1804         memcpy(loc_cpu_entry, repl->entries, repl->size);
1805 
1806         ret = translate_table(newinfo, loc_cpu_entry, repl);
1807         duprintf("arpt_register_table: translate table gives %d\n", ret);
1808         if (ret != 0)
1809                 goto out_free;
1810 
1811         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1812         if (IS_ERR(new_table)) {
1813                 ret = PTR_ERR(new_table);
1814                 goto out_free;
1815         }
1816         return new_table;
1817 
1818 out_free:
1819         xt_free_table_info(newinfo);
1820 out:
1821         return ERR_PTR(ret);
1822 }
1823 
1824 void arpt_unregister_table(struct xt_table *table)
1825 {
1826         struct xt_table_info *private;
1827         void *loc_cpu_entry;
1828         struct module *table_owner = table->me;
1829         struct arpt_entry *iter;
1830 
1831         private = xt_unregister_table(table);
1832 
1833         /* Decrease module usage counts and free resources */
1834         loc_cpu_entry = private->entries;
1835         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1836                 cleanup_entry(iter);
1837         if (private->number > private->initial_entries)
1838                 module_put(table_owner);
1839         xt_free_table_info(private);
1840 }
1841 
1842 /* The built-in targets: standard (NULL) and error. */
1843 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1844         {
1845                 .name             = XT_STANDARD_TARGET,
1846                 .targetsize       = sizeof(int),
1847                 .family           = NFPROTO_ARP,
1848 #ifdef CONFIG_COMPAT
1849                 .compatsize       = sizeof(compat_int_t),
1850                 .compat_from_user = compat_standard_from_user,
1851                 .compat_to_user   = compat_standard_to_user,
1852 #endif
1853         },
1854         {
1855                 .name             = XT_ERROR_TARGET,
1856                 .target           = arpt_error,
1857                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1858                 .family           = NFPROTO_ARP,
1859         },
1860 };
1861 
1862 static struct nf_sockopt_ops arpt_sockopts = {
1863         .pf             = PF_INET,
1864         .set_optmin     = ARPT_BASE_CTL,
1865         .set_optmax     = ARPT_SO_SET_MAX+1,
1866         .set            = do_arpt_set_ctl,
1867 #ifdef CONFIG_COMPAT
1868         .compat_set     = compat_do_arpt_set_ctl,
1869 #endif
1870         .get_optmin     = ARPT_BASE_CTL,
1871         .get_optmax     = ARPT_SO_GET_MAX+1,
1872         .get            = do_arpt_get_ctl,
1873 #ifdef CONFIG_COMPAT
1874         .compat_get     = compat_do_arpt_get_ctl,
1875 #endif
1876         .owner          = THIS_MODULE,
1877 };
1878 
1879 static int __net_init arp_tables_net_init(struct net *net)
1880 {
1881         return xt_proto_init(net, NFPROTO_ARP);
1882 }
1883 
1884 static void __net_exit arp_tables_net_exit(struct net *net)
1885 {
1886         xt_proto_fini(net, NFPROTO_ARP);
1887 }
1888 
1889 static struct pernet_operations arp_tables_net_ops = {
1890         .init = arp_tables_net_init,
1891         .exit = arp_tables_net_exit,
1892 };
1893 
1894 static int __init arp_tables_init(void)
1895 {
1896         int ret;
1897 
1898         ret = register_pernet_subsys(&arp_tables_net_ops);
1899         if (ret < 0)
1900                 goto err1;
1901 
1902         /* No one else will be downing sem now, so we won't sleep */
1903         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1904         if (ret < 0)
1905                 goto err2;
1906 
1907         /* Register setsockopt */
1908         ret = nf_register_sockopt(&arpt_sockopts);
1909         if (ret < 0)
1910                 goto err4;
1911 
1912         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1913         return 0;
1914 
1915 err4:
1916         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1917 err2:
1918         unregister_pernet_subsys(&arp_tables_net_ops);
1919 err1:
1920         return ret;
1921 }
1922 
1923 static void __exit arp_tables_fini(void)
1924 {
1925         nf_unregister_sockopt(&arpt_sockopts);
1926         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1927         unregister_pernet_subsys(&arp_tables_net_ops);
1928 }
1929 
1930 EXPORT_SYMBOL(arpt_register_table);
1931 EXPORT_SYMBOL(arpt_unregister_table);
1932 EXPORT_SYMBOL(arpt_do_table);
1933 
1934 module_init(arp_tables_init);
1935 module_exit(arp_tables_fini);
1936 

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