net/ipv4/netfilter/arp_tables.c

   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 <linux/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 void *arpt_alloc_initial_table(const struct xt_table *info)
  38 {
  39         return xt_alloc_initial_table(arpt, ARPT);
  40 }
  41 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  42
  43 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  44                                       const char *hdr_addr, int len)
  45 {
  46         int i, ret;
  47
  48         if (len > ARPT_DEV_ADDR_LEN_MAX)
  49                 len = ARPT_DEV_ADDR_LEN_MAX;
  50
  51         ret = 0;
  52         for (i = 0; i < len; i++)
  53                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  54
  55         return ret != 0;
  56 }
  57
  58 /*
  59  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  60  * Some arches dont care, unrolling the loop is a win on them.
  61  * For other arches, we only have a 16bit alignement.
  62  */
  63 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  64 {
  65 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  66         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  67 #else
  68         unsigned long ret = 0;
  69         const u16 *a = (const u16 *)_a;
  70         const u16 *b = (const u16 *)_b;
  71         const u16 *mask = (const u16 *)_mask;
  72         int i;
  73
  74         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  75                 ret |= (a[i] ^ b[i]) & mask[i];
  76 #endif
  77         return ret;
  78 }
  79
  80 /* Returns whether packet matches rule or not. */
  81 static inline int arp_packet_match(const struct arphdr *arphdr,
  82                                    struct net_device *dev,
  83                                    const char *indev,
  84                                    const char *outdev,
  85                                    const struct arpt_arp *arpinfo)
  86 {
  87         const char *arpptr = (char *)(arphdr + 1);
  88         const char *src_devaddr, *tgt_devaddr;
  89         __be32 src_ipaddr, tgt_ipaddr;
  90         long ret;
  91
  92         if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
  93                     (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
  94                 return 0;
  95
  96         if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
  97                     (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
  98                 return 0;
  99
 100         if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
 101                     (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
 102                 return 0;
 103
 104         if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
 105                     (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
 106                 return 0;
 107
 108         src_devaddr = arpptr;
 109         arpptr += dev->addr_len;
 110         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 111         arpptr += sizeof(u32);
 112         tgt_devaddr = arpptr;
 113         arpptr += dev->addr_len;
 114         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 115
 116         if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
 117                     arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
 118                                         dev->addr_len)) ||
 119             NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
 120                     arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
 121                                         dev->addr_len)))
 122                 return 0;
 123
 124         if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
 125                     (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
 126             NF_INVF(arpinfo, ARPT_INV_TGTIP,
 127                     (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
 128                 return 0;
 129
 130         /* Look for ifname matches.  */
 131         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 132
 133         if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
 134                 return 0;
 135
 136         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 137
 138         if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
 139                 return 0;
 140
 141         return 1;
 142 }
 143
 144 static inline int arp_checkentry(const struct arpt_arp *arp)
 145 {
 146         if (arp->flags & ~ARPT_F_MASK)
 147                 return 0;
 148         if (arp->invflags & ~ARPT_INV_MASK)
 149                 return 0;
 150
 151         return 1;
 152 }
 153
 154 static unsigned int
 155 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 156 {
 157         net_err_ratelimited("arp_tables: error: '%s'\n",
 158                             (const char *)par->targinfo);
 159
 160         return NF_DROP;
 161 }
 162
 163 static inline const struct xt_entry_target *
 164 arpt_get_target_c(const struct arpt_entry *e)
 165 {
 166         return arpt_get_target((struct arpt_entry *)e);
 167 }
 168
 169 static inline struct arpt_entry *
 170 get_entry(const void *base, unsigned int offset)
 171 {
 172         return (struct arpt_entry *)(base + offset);
 173 }
 174
 175 static inline
 176 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 177 {
 178         return (void *)entry + entry->next_offset;
 179 }
 180
 181 unsigned int arpt_do_table(struct sk_buff *skb,
 182                            const struct nf_hook_state *state,
 183                            struct xt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 187         unsigned int verdict = NF_DROP;
 188         const struct arphdr *arp;
 189         struct arpt_entry *e, **jumpstack;
 190         const char *indev, *outdev;
 191         const void *table_base;
 192         unsigned int cpu, stackidx = 0;
 193         const struct xt_table_info *private;
 194         struct xt_action_param acpar;
 195         unsigned int addend;
 196
 197         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 198                 return NF_DROP;
 199
 200         indev = state->in ? state->in->name : nulldevname;
 201         outdev = state->out ? state->out->name : nulldevname;
 202
 203         local_bh_disable();
 204         addend = xt_write_recseq_begin();
 205         private = table->private;
 206         cpu     = smp_processor_id();
 207         /*
 208          * Ensure we load private-> members after we've fetched the base
 209          * pointer.
 210          */
 211         smp_read_barrier_depends();
 212         table_base = private->entries;
 213         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 214
 215         /* No TEE support for arptables, so no need to switch to alternate
 216          * stack.  All targets that reenter must return absolute verdicts.
 217          */
 218         e = get_entry(table_base, private->hook_entry[hook]);
 219
 220         acpar.state   = state;
 221         acpar.hotdrop = false;
 222
 223         arp = arp_hdr(skb);
 224         do {
 225                 const struct xt_entry_target *t;
 226                 struct xt_counters *counter;
 227
 228                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 229                         e = arpt_next_entry(e);
 230                         continue;
 231                 }
 232
 233                 counter = xt_get_this_cpu_counter(&e->counters);
 234                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 235
 236                 t = arpt_get_target_c(e);
 237
 238                 /* Standard target? */
 239                 if (!t->u.kernel.target->target) {
 240                         int v;
 241
 242                         v = ((struct xt_standard_target *)t)->verdict;
 243                         if (v < 0) {
 244                                 /* Pop from stack? */
 245                                 if (v != XT_RETURN) {
 246                                         verdict = (unsigned int)(-v) - 1;
 247                                         break;
 248                                 }
 249                                 if (stackidx == 0) {
 250                                         e = get_entry(table_base,
 251                                                       private->underflow[hook]);
 252                                 } else {
 253                                         e = jumpstack[--stackidx];
 254                                         e = arpt_next_entry(e);
 255                                 }
 256                                 continue;
 257                         }
 258                         if (table_base + v
 259                             != arpt_next_entry(e)) {
 260                                 jumpstack[stackidx++] = e;
 261                         }
 262
 263                         e = get_entry(table_base, v);
 264                         continue;
 265                 }
 266
 267                 acpar.target   = t->u.kernel.target;
 268                 acpar.targinfo = t->data;
 269                 verdict = t->u.kernel.target->target(skb, &acpar);
 270
 271                 /* Target might have changed stuff. */
 272                 arp = arp_hdr(skb);
 273
 274                 if (verdict == XT_CONTINUE)
 275                         e = arpt_next_entry(e);
 276                 else
 277                         /* Verdict */
 278                         break;
 279         } while (!acpar.hotdrop);
 280         xt_write_recseq_end(addend);
 281         local_bh_enable();
 282
 283         if (acpar.hotdrop)
 284                 return NF_DROP;
 285         else
 286                 return verdict;
 287 }
 288
 289 /* All zeroes == unconditional rule. */
 290 static inline bool unconditional(const struct arpt_entry *e)
 291 {
 292         static const struct arpt_arp uncond;
 293
 294         return e->target_offset == sizeof(struct arpt_entry) &&
 295                memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
 296 }
 297
 298 /* Figures out from what hook each rule can be called: returns 0 if
 299  * there are loops.  Puts hook bitmask in comefrom.
 300  */
 301 static int mark_source_chains(const struct xt_table_info *newinfo,
 302                               unsigned int valid_hooks, void *entry0,
 303                               unsigned int *offsets)
 304 {
 305         unsigned int hook;
 306
 307         /* No recursion; use packet counter to save back ptrs (reset
 308          * to 0 as we leave), and comefrom to save source hook bitmask.
 309          */
 310         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 311                 unsigned int pos = newinfo->hook_entry[hook];
 312                 struct arpt_entry *e
 313                         = (struct arpt_entry *)(entry0 + pos);
 314
 315                 if (!(valid_hooks & (1 << hook)))
 316                         continue;
 317
 318                 /* Set initial back pointer. */
 319                 e->counters.pcnt = pos;
 320
 321                 for (;;) {
 322                         const struct xt_standard_target *t
 323                                 = (void *)arpt_get_target_c(e);
 324                         int visited = e->comefrom & (1 << hook);
 325
 326                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
 327                                 return 0;
 328
 329                         e->comefrom
 330                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 331
 332                         /* Unconditional return/END. */
 333                         if ((unconditional(e) &&
 334                              (strcmp(t->target.u.user.name,
 335                                      XT_STANDARD_TARGET) == 0) &&
 336                              t->verdict < 0) || visited) {
 337                                 unsigned int oldpos, size;
 338
 339                                 if ((strcmp(t->target.u.user.name,
 340                                             XT_STANDARD_TARGET) == 0) &&
 341                                     t->verdict < -NF_MAX_VERDICT - 1)
 342                                         return 0;
 343
 344                                 /* Return: backtrack through the last
 345                                  * big jump.
 346                                  */
 347                                 do {
 348                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 349                                         oldpos = pos;
 350                                         pos = e->counters.pcnt;
 351                                         e->counters.pcnt = 0;
 352
 353                                         /* We're at the start. */
 354                                         if (pos == oldpos)
 355                                                 goto next;
 356
 357                                         e = (struct arpt_entry *)
 358                                                 (entry0 + pos);
 359                                 } while (oldpos == pos + e->next_offset);
 360
 361                                 /* Move along one */
 362                                 size = e->next_offset;
 363                                 e = (struct arpt_entry *)
 364                                         (entry0 + pos + size);
 365                                 if (pos + size >= newinfo->size)
 366                                         return 0;
 367                                 e->counters.pcnt = pos;
 368                                 pos += size;
 369                         } else {
 370                                 int newpos = t->verdict;
 371
 372                                 if (strcmp(t->target.u.user.name,
 373                                            XT_STANDARD_TARGET) == 0 &&
 374                                     newpos >= 0) {
 375                                         /* This a jump; chase it. */
 376                                         if (!xt_find_jump_offset(offsets, newpos,
 377                                                                  newinfo->number))
 378                                                 return 0;
 379                                         e = (struct arpt_entry *)
 380                                                 (entry0 + newpos);
 381                                 } else {
 382                                         /* ... this is a fallthru */
 383                                         newpos = pos + e->next_offset;
 384                                         if (newpos >= newinfo->size)
 385                                                 return 0;
 386                                 }
 387                                 e = (struct arpt_entry *)
 388                                         (entry0 + newpos);
 389                                 e->counters.pcnt = pos;
 390                                 pos = newpos;
 391                         }
 392                 }
 393 next:           ;
 394         }
 395         return 1;
 396 }
 397
 398 static inline int check_target(struct arpt_entry *e, const char *name)
 399 {
 400         struct xt_entry_target *t = arpt_get_target(e);
 401         struct xt_tgchk_param par = {
 402                 .table     = name,
 403                 .entryinfo = e,
 404                 .target    = t->u.kernel.target,
 405                 .targinfo  = t->data,
 406                 .hook_mask = e->comefrom,
 407                 .family    = NFPROTO_ARP,
 408         };
 409
 410         return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 411 }
 412
 413 static inline int
 414 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 415                  struct xt_percpu_counter_alloc_state *alloc_state)
 416 {
 417         struct xt_entry_target *t;
 418         struct xt_target *target;
 419         int ret;
 420
 421         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 422                 return -ENOMEM;
 423
 424         t = arpt_get_target(e);
 425         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 426                                         t->u.user.revision);
 427         if (IS_ERR(target)) {
 428                 ret = PTR_ERR(target);
 429                 goto out;
 430         }
 431         t->u.kernel.target = target;
 432
 433         ret = check_target(e, name);
 434         if (ret)
 435                 goto err;
 436         return 0;
 437 err:
 438         module_put(t->u.kernel.target->me);
 439 out:
 440         xt_percpu_counter_free(&e->counters);
 441
 442         return ret;
 443 }
 444
 445 static bool check_underflow(const struct arpt_entry *e)
 446 {
 447         const struct xt_entry_target *t;
 448         unsigned int verdict;
 449
 450         if (!unconditional(e))
 451                 return false;
 452         t = arpt_get_target_c(e);
 453         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 454                 return false;
 455         verdict = ((struct xt_standard_target *)t)->verdict;
 456         verdict = -verdict - 1;
 457         return verdict == NF_DROP || verdict == NF_ACCEPT;
 458 }
 459
 460 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 461                                              struct xt_table_info *newinfo,
 462                                              const unsigned char *base,
 463                                              const unsigned char *limit,
 464                                              const unsigned int *hook_entries,
 465                                              const unsigned int *underflows,
 466                                              unsigned int valid_hooks)
 467 {
 468         unsigned int h;
 469         int err;
 470
 471         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 472             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 473             (unsigned char *)e + e->next_offset > limit)
 474                 return -EINVAL;
 475
 476         if (e->next_offset
 477             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
 478                 return -EINVAL;
 479
 480         if (!arp_checkentry(&e->arp))
 481                 return -EINVAL;
 482
 483         err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 484                                      e->next_offset);
 485         if (err)
 486                 return err;
 487
 488         /* Check hooks & underflows */
 489         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 490                 if (!(valid_hooks & (1 << h)))
 491                         continue;
 492                 if ((unsigned char *)e - base == hook_entries[h])
 493                         newinfo->hook_entry[h] = hook_entries[h];
 494                 if ((unsigned char *)e - base == underflows[h]) {
 495                         if (!check_underflow(e))
 496                                 return -EINVAL;
 497
 498                         newinfo->underflow[h] = underflows[h];
 499                 }
 500         }
 501
 502         /* Clear counters and comefrom */
 503         e->counters = ((struct xt_counters) { 0, 0 });
 504         e->comefrom = 0;
 505         return 0;
 506 }
 507
 508 static inline void cleanup_entry(struct arpt_entry *e)
 509 {
 510         struct xt_tgdtor_param par;
 511         struct xt_entry_target *t;
 512
 513         t = arpt_get_target(e);
 514         par.target   = t->u.kernel.target;
 515         par.targinfo = t->data;
 516         par.family   = NFPROTO_ARP;
 517         if (par.target->destroy != NULL)
 518                 par.target->destroy(&par);
 519         module_put(par.target->me);
 520         xt_percpu_counter_free(&e->counters);
 521 }
 522
 523 /* Checks and translates the user-supplied table segment (held in
 524  * newinfo).
 525  */
 526 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 527                            const struct arpt_replace *repl)
 528 {
 529         struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 530         struct arpt_entry *iter;
 531         unsigned int *offsets;
 532         unsigned int i;
 533         int ret = 0;
 534
 535         newinfo->size = repl->size;
 536         newinfo->number = repl->num_entries;
 537
 538         /* Init all hooks to impossible value. */
 539         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 540                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 541                 newinfo->underflow[i] = 0xFFFFFFFF;
 542         }
 543
 544         offsets = xt_alloc_entry_offsets(newinfo->number);
 545         if (!offsets)
 546                 return -ENOMEM;
 547         i = 0;
 548
 549         /* Walk through entries, checking offsets. */
 550         xt_entry_foreach(iter, entry0, newinfo->size) {
 551                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 552                                                  entry0 + repl->size,
 553                                                  repl->hook_entry,
 554                                                  repl->underflow,
 555                                                  repl->valid_hooks);
 556                 if (ret != 0)
 557                         goto out_free;
 558                 if (i < repl->num_entries)
 559                         offsets[i] = (void *)iter - entry0;
 560                 ++i;
 561                 if (strcmp(arpt_get_target(iter)->u.user.name,
 562                     XT_ERROR_TARGET) == 0)
 563                         ++newinfo->stacksize;
 564         }
 565         if (ret != 0)
 566                 goto out_free;
 567
 568         ret = -EINVAL;
 569         if (i != repl->num_entries)
 570                 goto out_free;
 571
 572         /* Check hooks all assigned */
 573         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 574                 /* Only hooks which are valid */
 575                 if (!(repl->valid_hooks & (1 << i)))
 576                         continue;
 577                 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
 578                         goto out_free;
 579                 if (newinfo->underflow[i] == 0xFFFFFFFF)
 580                         goto out_free;
 581         }
 582
 583         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 584                 ret = -ELOOP;
 585                 goto out_free;
 586         }
 587         kvfree(offsets);
 588
 589         /* Finally, each sanity check must pass */
 590         i = 0;
 591         xt_entry_foreach(iter, entry0, newinfo->size) {
 592                 ret = find_check_entry(iter, repl->name, repl->size,
 593                                        &alloc_state);
 594                 if (ret != 0)
 595                         break;
 596                 ++i;
 597         }
 598
 599         if (ret != 0) {
 600                 xt_entry_foreach(iter, entry0, newinfo->size) {
 601                         if (i-- == 0)
 602                                 break;
 603                         cleanup_entry(iter);
 604                 }
 605                 return ret;
 606         }
 607
 608         return ret;
 609  out_free:
 610         kvfree(offsets);
 611         return ret;
 612 }
 613
 614 static void get_counters(const struct xt_table_info *t,
 615                          struct xt_counters counters[])
 616 {
 617         struct arpt_entry *iter;
 618         unsigned int cpu;
 619         unsigned int i;
 620
 621         for_each_possible_cpu(cpu) {
 622                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 623
 624                 i = 0;
 625                 xt_entry_foreach(iter, t->entries, t->size) {
 626                         struct xt_counters *tmp;
 627                         u64 bcnt, pcnt;
 628                         unsigned int start;
 629
 630                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 631                         do {
 632                                 start = read_seqcount_begin(s);
 633                                 bcnt = tmp->bcnt;
 634                                 pcnt = tmp->pcnt;
 635                         } while (read_seqcount_retry(s, start));
 636
 637                         ADD_COUNTER(counters[i], bcnt, pcnt);
 638                         ++i;
 639                 }
 640         }
 641 }
 642
 643 static struct xt_counters *alloc_counters(const struct xt_table *table)
 644 {
 645         unsigned int countersize;
 646         struct xt_counters *counters;
 647         const struct xt_table_info *private = table->private;
 648
 649         /* We need atomic snapshot of counters: rest doesn't change
 650          * (other than comefrom, which userspace doesn't care
 651          * about).
 652          */
 653         countersize = sizeof(struct xt_counters) * private->number;
 654         counters = vzalloc(countersize);
 655
 656         if (counters == NULL)
 657                 return ERR_PTR(-ENOMEM);
 658
 659         get_counters(private, counters);
 660
 661         return counters;
 662 }
 663
 664 static int copy_entries_to_user(unsigned int total_size,
 665                                 const struct xt_table *table,
 666                                 void __user *userptr)
 667 {
 668         unsigned int off, num;
 669         const struct arpt_entry *e;
 670         struct xt_counters *counters;
 671         struct xt_table_info *private = table->private;
 672         int ret = 0;
 673         void *loc_cpu_entry;
 674
 675         counters = alloc_counters(table);
 676         if (IS_ERR(counters))
 677                 return PTR_ERR(counters);
 678
 679         loc_cpu_entry = private->entries;
 680         /* ... then copy entire thing ... */
 681         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 682                 ret = -EFAULT;
 683                 goto free_counters;
 684         }
 685
 686         /* FIXME: use iterator macros --RR */
 687         /* ... then go back and fix counters and names */
 688         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 689                 const struct xt_entry_target *t;
 690
 691                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 692                 if (copy_to_user(userptr + off
 693                                  + offsetof(struct arpt_entry, counters),
 694                                  &counters[num],
 695                                  sizeof(counters[num])) != 0) {
 696                         ret = -EFAULT;
 697                         goto free_counters;
 698                 }
 699
 700                 t = arpt_get_target_c(e);
 701                 if (copy_to_user(userptr + off + e->target_offset
 702                                  + offsetof(struct xt_entry_target,
 703                                             u.user.name),
 704                                  t->u.kernel.target->name,
 705                                  strlen(t->u.kernel.target->name)+1) != 0) {
 706                         ret = -EFAULT;
 707                         goto free_counters;
 708                 }
 709         }
 710
 711  free_counters:
 712         vfree(counters);
 713         return ret;
 714 }
 715
 716 #ifdef CONFIG_COMPAT
 717 static void compat_standard_from_user(void *dst, const void *src)
 718 {
 719         int v = *(compat_int_t *)src;
 720
 721         if (v > 0)
 722                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 723         memcpy(dst, &v, sizeof(v));
 724 }
 725
 726 static int compat_standard_to_user(void __user *dst, const void *src)
 727 {
 728         compat_int_t cv = *(int *)src;
 729
 730         if (cv > 0)
 731                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 732         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 733 }
 734
 735 static int compat_calc_entry(const struct arpt_entry *e,
 736                              const struct xt_table_info *info,
 737                              const void *base, struct xt_table_info *newinfo)
 738 {
 739         const struct xt_entry_target *t;
 740         unsigned int entry_offset;
 741         int off, i, ret;
 742
 743         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 744         entry_offset = (void *)e - base;
 745
 746         t = arpt_get_target_c(e);
 747         off += xt_compat_target_offset(t->u.kernel.target);
 748         newinfo->size -= off;
 749         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 750         if (ret)
 751                 return ret;
 752
 753         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 754                 if (info->hook_entry[i] &&
 755                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 756                         newinfo->hook_entry[i] -= off;
 757                 if (info->underflow[i] &&
 758                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 759                         newinfo->underflow[i] -= off;
 760         }
 761         return 0;
 762 }
 763
 764 static int compat_table_info(const struct xt_table_info *info,
 765                              struct xt_table_info *newinfo)
 766 {
 767         struct arpt_entry *iter;
 768         const void *loc_cpu_entry;
 769         int ret;
 770
 771         if (!newinfo || !info)
 772                 return -EINVAL;
 773
 774         /* we dont care about newinfo->entries */
 775         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 776         newinfo->initial_entries = 0;
 777         loc_cpu_entry = info->entries;
 778         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 779         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 780                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 781                 if (ret != 0)
 782                         return ret;
 783         }
 784         return 0;
 785 }
 786 #endif
 787
 788 static int get_info(struct net *net, void __user *user,
 789                     const int *len, int compat)
 790 {
 791         char name[XT_TABLE_MAXNAMELEN];
 792         struct xt_table *t;
 793         int ret;
 794
 795         if (*len != sizeof(struct arpt_getinfo))
 796                 return -EINVAL;
 797
 798         if (copy_from_user(name, user, sizeof(name)) != 0)
 799                 return -EFAULT;
 800
 801         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 802 #ifdef CONFIG_COMPAT
 803         if (compat)
 804                 xt_compat_lock(NFPROTO_ARP);
 805 #endif
 806         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 807                                     "arptable_%s", name);
 808         if (t) {
 809                 struct arpt_getinfo info;
 810                 const struct xt_table_info *private = t->private;
 811 #ifdef CONFIG_COMPAT
 812                 struct xt_table_info tmp;
 813
 814                 if (compat) {
 815                         ret = compat_table_info(private, &tmp);
 816                         xt_compat_flush_offsets(NFPROTO_ARP);
 817                         private = &tmp;
 818                 }
 819 #endif
 820                 memset(&info, 0, sizeof(info));
 821                 info.valid_hooks = t->valid_hooks;
 822                 memcpy(info.hook_entry, private->hook_entry,
 823                        sizeof(info.hook_entry));
 824                 memcpy(info.underflow, private->underflow,
 825                        sizeof(info.underflow));
 826                 info.num_entries = private->number;
 827                 info.size = private->size;
 828                 strcpy(info.name, name);
 829
 830                 if (copy_to_user(user, &info, *len) != 0)
 831                         ret = -EFAULT;
 832                 else
 833                         ret = 0;
 834                 xt_table_unlock(t);
 835                 module_put(t->me);
 836         } else
 837                 ret = -ENOENT;
 838 #ifdef CONFIG_COMPAT
 839         if (compat)
 840                 xt_compat_unlock(NFPROTO_ARP);
 841 #endif
 842         return ret;
 843 }
 844
 845 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 846                        const int *len)
 847 {
 848         int ret;
 849         struct arpt_get_entries get;
 850         struct xt_table *t;
 851
 852         if (*len < sizeof(get))
 853                 return -EINVAL;
 854         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 855                 return -EFAULT;
 856         if (*len != sizeof(struct arpt_get_entries) + get.size)
 857                 return -EINVAL;
 858
 859         get.name[sizeof(get.name) - 1] = '\0';
 860
 861         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 862         if (t) {
 863                 const struct xt_table_info *private = t->private;
 864
 865                 if (get.size == private->size)
 866                         ret = copy_entries_to_user(private->size,
 867                                                    t, uptr->entrytable);
 868                 else
 869                         ret = -EAGAIN;
 870
 871                 module_put(t->me);
 872                 xt_table_unlock(t);
 873         } else
 874                 ret = -ENOENT;
 875
 876         return ret;
 877 }
 878
 879 static int __do_replace(struct net *net, const char *name,
 880                         unsigned int valid_hooks,
 881                         struct xt_table_info *newinfo,
 882                         unsigned int num_counters,
 883                         void __user *counters_ptr)
 884 {
 885         int ret;
 886         struct xt_table *t;
 887         struct xt_table_info *oldinfo;
 888         struct xt_counters *counters;
 889         void *loc_cpu_old_entry;
 890         struct arpt_entry *iter;
 891
 892         ret = 0;
 893         counters = vzalloc(num_counters * sizeof(struct xt_counters));
 894         if (!counters) {
 895                 ret = -ENOMEM;
 896                 goto out;
 897         }
 898
 899         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 900                                     "arptable_%s", name);
 901         if (!t) {
 902                 ret = -ENOENT;
 903                 goto free_newinfo_counters_untrans;
 904         }
 905
 906         /* You lied! */
 907         if (valid_hooks != t->valid_hooks) {
 908                 ret = -EINVAL;
 909                 goto put_module;
 910         }
 911
 912         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
 913         if (!oldinfo)
 914                 goto put_module;
 915
 916         /* Update module usage count based on number of rules */
 917         if ((oldinfo->number > oldinfo->initial_entries) ||
 918             (newinfo->number <= oldinfo->initial_entries))
 919                 module_put(t->me);
 920         if ((oldinfo->number > oldinfo->initial_entries) &&
 921             (newinfo->number <= oldinfo->initial_entries))
 922                 module_put(t->me);
 923
 924         /* Get the old counters, and synchronize with replace */
 925         get_counters(oldinfo, counters);
 926
 927         /* Decrease module usage counts and free resource */
 928         loc_cpu_old_entry = oldinfo->entries;
 929         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
 930                 cleanup_entry(iter);
 931
 932         xt_free_table_info(oldinfo);
 933         if (copy_to_user(counters_ptr, counters,
 934                          sizeof(struct xt_counters) * num_counters) != 0) {
 935                 /* Silent error, can't fail, new table is already in place */
 936                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
 937         }
 938         vfree(counters);
 939         xt_table_unlock(t);
 940         return ret;
 941
 942  put_module:
 943         module_put(t->me);
 944         xt_table_unlock(t);
 945  free_newinfo_counters_untrans:
 946         vfree(counters);
 947  out:
 948         return ret;
 949 }
 950
 951 static int do_replace(struct net *net, const void __user *user,
 952                       unsigned int len)
 953 {
 954         int ret;
 955         struct arpt_replace tmp;
 956         struct xt_table_info *newinfo;
 957         void *loc_cpu_entry;
 958         struct arpt_entry *iter;
 959
 960         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 961                 return -EFAULT;
 962
 963         /* overflow check */
 964         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 965                 return -ENOMEM;
 966         if (tmp.num_counters == 0)
 967                 return -EINVAL;
 968
 969         tmp.name[sizeof(tmp.name)-1] = 0;
 970
 971         newinfo = xt_alloc_table_info(tmp.size);
 972         if (!newinfo)
 973                 return -ENOMEM;
 974
 975         loc_cpu_entry = newinfo->entries;
 976         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 977                            tmp.size) != 0) {
 978                 ret = -EFAULT;
 979                 goto free_newinfo;
 980         }
 981
 982         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
 983         if (ret != 0)
 984                 goto free_newinfo;
 985
 986         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
 987                            tmp.num_counters, tmp.counters);
 988         if (ret)
 989                 goto free_newinfo_untrans;
 990         return 0;
 991
 992  free_newinfo_untrans:
 993         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
 994                 cleanup_entry(iter);
 995  free_newinfo:
 996         xt_free_table_info(newinfo);
 997         return ret;
 998 }
 999
1000 static int do_add_counters(struct net *net, const void __user *user,
1001                            unsigned int len, int compat)
1002 {
1003         unsigned int i;
1004         struct xt_counters_info tmp;
1005         struct xt_counters *paddc;
1006         struct xt_table *t;
1007         const struct xt_table_info *private;
1008         int ret = 0;
1009         struct arpt_entry *iter;
1010         unsigned int addend;
1011
1012         paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1013         if (IS_ERR(paddc))
1014                 return PTR_ERR(paddc);
1015
1016         t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1017         if (!t) {
1018                 ret = -ENOENT;
1019                 goto free;
1020         }
1021
1022         local_bh_disable();
1023         private = t->private;
1024         if (private->number != tmp.num_counters) {
1025                 ret = -EINVAL;
1026                 goto unlock_up_free;
1027         }
1028
1029         i = 0;
1030
1031         addend = xt_write_recseq_begin();
1032         xt_entry_foreach(iter,  private->entries, private->size) {
1033                 struct xt_counters *tmp;
1034
1035                 tmp = xt_get_this_cpu_counter(&iter->counters);
1036                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1037                 ++i;
1038         }
1039         xt_write_recseq_end(addend);
1040  unlock_up_free:
1041         local_bh_enable();
1042         xt_table_unlock(t);
1043         module_put(t->me);
1044  free:
1045         vfree(paddc);
1046
1047         return ret;
1048 }
1049
1050 #ifdef CONFIG_COMPAT
1051 struct compat_arpt_replace {
1052         char                            name[XT_TABLE_MAXNAMELEN];
1053         u32                             valid_hooks;
1054         u32                             num_entries;
1055         u32                             size;
1056         u32                             hook_entry[NF_ARP_NUMHOOKS];
1057         u32                             underflow[NF_ARP_NUMHOOKS];
1058         u32                             num_counters;
1059         compat_uptr_t                   counters;
1060         struct compat_arpt_entry        entries[0];
1061 };
1062
1063 static inline void compat_release_entry(struct compat_arpt_entry *e)
1064 {
1065         struct xt_entry_target *t;
1066
1067         t = compat_arpt_get_target(e);
1068         module_put(t->u.kernel.target->me);
1069 }
1070
1071 static int
1072 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1073                                   struct xt_table_info *newinfo,
1074                                   unsigned int *size,
1075                                   const unsigned char *base,
1076                                   const unsigned char *limit)
1077 {
1078         struct xt_entry_target *t;
1079         struct xt_target *target;
1080         unsigned int entry_offset;
1081         int ret, off;
1082
1083         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1084             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1085             (unsigned char *)e + e->next_offset > limit)
1086                 return -EINVAL;
1087
1088         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1089                              sizeof(struct compat_xt_entry_target))
1090                 return -EINVAL;
1091
1092         if (!arp_checkentry(&e->arp))
1093                 return -EINVAL;
1094
1095         ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1096                                             e->next_offset);
1097         if (ret)
1098                 return ret;
1099
1100         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1101         entry_offset = (void *)e - (void *)base;
1102
1103         t = compat_arpt_get_target(e);
1104         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1105                                         t->u.user.revision);
1106         if (IS_ERR(target)) {
1107                 ret = PTR_ERR(target);
1108                 goto out;
1109         }
1110         t->u.kernel.target = target;
1111
1112         off += xt_compat_target_offset(target);
1113         *size += off;
1114         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1115         if (ret)
1116                 goto release_target;
1117
1118         return 0;
1119
1120 release_target:
1121         module_put(t->u.kernel.target->me);
1122 out:
1123         return ret;
1124 }
1125
1126 static void
1127 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1128                             unsigned int *size,
1129                             struct xt_table_info *newinfo, unsigned char *base)
1130 {
1131         struct xt_entry_target *t;
1132         struct xt_target *target;
1133         struct arpt_entry *de;
1134         unsigned int origsize;
1135         int h;
1136
1137         origsize = *size;
1138         de = (struct arpt_entry *)*dstptr;
1139         memcpy(de, e, sizeof(struct arpt_entry));
1140         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1141
1142         *dstptr += sizeof(struct arpt_entry);
1143         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1144
1145         de->target_offset = e->target_offset - (origsize - *size);
1146         t = compat_arpt_get_target(e);
1147         target = t->u.kernel.target;
1148         xt_compat_target_from_user(t, dstptr, size);
1149
1150         de->next_offset = e->next_offset - (origsize - *size);
1151         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1152                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1153                         newinfo->hook_entry[h] -= origsize - *size;
1154                 if ((unsigned char *)de - base < newinfo->underflow[h])
1155                         newinfo->underflow[h] -= origsize - *size;
1156         }
1157 }
1158
1159 static int translate_compat_table(struct xt_table_info **pinfo,
1160                                   void **pentry0,
1161                                   const struct compat_arpt_replace *compatr)
1162 {
1163         unsigned int i, j;
1164         struct xt_table_info *newinfo, *info;
1165         void *pos, *entry0, *entry1;
1166         struct compat_arpt_entry *iter0;
1167         struct arpt_replace repl;
1168         unsigned int size;
1169         int ret = 0;
1170
1171         info = *pinfo;
1172         entry0 = *pentry0;
1173         size = compatr->size;
1174         info->number = compatr->num_entries;
1175
1176         j = 0;
1177         xt_compat_lock(NFPROTO_ARP);
1178         xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1179         /* Walk through entries, checking offsets. */
1180         xt_entry_foreach(iter0, entry0, compatr->size) {
1181                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1182                                                         entry0,
1183                                                         entry0 + compatr->size);
1184                 if (ret != 0)
1185                         goto out_unlock;
1186                 ++j;
1187         }
1188
1189         ret = -EINVAL;
1190         if (j != compatr->num_entries)
1191                 goto out_unlock;
1192
1193         ret = -ENOMEM;
1194         newinfo = xt_alloc_table_info(size);
1195         if (!newinfo)
1196                 goto out_unlock;
1197
1198         newinfo->number = compatr->num_entries;
1199         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1200                 newinfo->hook_entry[i] = compatr->hook_entry[i];
1201                 newinfo->underflow[i] = compatr->underflow[i];
1202         }
1203         entry1 = newinfo->entries;
1204         pos = entry1;
1205         size = compatr->size;
1206         xt_entry_foreach(iter0, entry0, compatr->size)
1207                 compat_copy_entry_from_user(iter0, &pos, &size,
1208                                             newinfo, entry1);
1209
1210         /* all module references in entry0 are now gone */
1211
1212         xt_compat_flush_offsets(NFPROTO_ARP);
1213         xt_compat_unlock(NFPROTO_ARP);
1214
1215         memcpy(&repl, compatr, sizeof(*compatr));
1216
1217         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1218                 repl.hook_entry[i] = newinfo->hook_entry[i];
1219                 repl.underflow[i] = newinfo->underflow[i];
1220         }
1221
1222         repl.num_counters = 0;
1223         repl.counters = NULL;
1224         repl.size = newinfo->size;
1225         ret = translate_table(newinfo, entry1, &repl);
1226         if (ret)
1227                 goto free_newinfo;
1228
1229         *pinfo = newinfo;
1230         *pentry0 = entry1;
1231         xt_free_table_info(info);
1232         return 0;
1233
1234 free_newinfo:
1235         xt_free_table_info(newinfo);
1236         return ret;
1237 out_unlock:
1238         xt_compat_flush_offsets(NFPROTO_ARP);
1239         xt_compat_unlock(NFPROTO_ARP);
1240         xt_entry_foreach(iter0, entry0, compatr->size) {
1241                 if (j-- == 0)
1242                         break;
1243                 compat_release_entry(iter0);
1244         }
1245         return ret;
1246 }
1247
1248 static int compat_do_replace(struct net *net, void __user *user,
1249                              unsigned int len)
1250 {
1251         int ret;
1252         struct compat_arpt_replace tmp;
1253         struct xt_table_info *newinfo;
1254         void *loc_cpu_entry;
1255         struct arpt_entry *iter;
1256
1257         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1258                 return -EFAULT;
1259
1260         /* overflow check */
1261         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1262                 return -ENOMEM;
1263         if (tmp.num_counters == 0)
1264                 return -EINVAL;
1265
1266         tmp.name[sizeof(tmp.name)-1] = 0;
1267
1268         newinfo = xt_alloc_table_info(tmp.size);
1269         if (!newinfo)
1270                 return -ENOMEM;
1271
1272         loc_cpu_entry = newinfo->entries;
1273         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1274                 ret = -EFAULT;
1275                 goto free_newinfo;
1276         }
1277
1278         ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1279         if (ret != 0)
1280                 goto free_newinfo;
1281
1282         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1283                            tmp.num_counters, compat_ptr(tmp.counters));
1284         if (ret)
1285                 goto free_newinfo_untrans;
1286         return 0;
1287
1288  free_newinfo_untrans:
1289         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1290                 cleanup_entry(iter);
1291  free_newinfo:
1292         xt_free_table_info(newinfo);
1293         return ret;
1294 }
1295
1296 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1297                                   unsigned int len)
1298 {
1299         int ret;
1300
1301         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1302                 return -EPERM;
1303
1304         switch (cmd) {
1305         case ARPT_SO_SET_REPLACE:
1306                 ret = compat_do_replace(sock_net(sk), user, len);
1307                 break;
1308
1309         case ARPT_SO_SET_ADD_COUNTERS:
1310                 ret = do_add_counters(sock_net(sk), user, len, 1);
1311                 break;
1312
1313         default:
1314                 ret = -EINVAL;
1315         }
1316
1317         return ret;
1318 }
1319
1320 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1321                                      compat_uint_t *size,
1322                                      struct xt_counters *counters,
1323                                      unsigned int i)
1324 {
1325         struct xt_entry_target *t;
1326         struct compat_arpt_entry __user *ce;
1327         u_int16_t target_offset, next_offset;
1328         compat_uint_t origsize;
1329         int ret;
1330
1331         origsize = *size;
1332         ce = (struct compat_arpt_entry __user *)*dstptr;
1333         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1334             copy_to_user(&ce->counters, &counters[i],
1335             sizeof(counters[i])) != 0)
1336                 return -EFAULT;
1337
1338         *dstptr += sizeof(struct compat_arpt_entry);
1339         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1340
1341         target_offset = e->target_offset - (origsize - *size);
1342
1343         t = arpt_get_target(e);
1344         ret = xt_compat_target_to_user(t, dstptr, size);
1345         if (ret)
1346                 return ret;
1347         next_offset = e->next_offset - (origsize - *size);
1348         if (put_user(target_offset, &ce->target_offset) != 0 ||
1349             put_user(next_offset, &ce->next_offset) != 0)
1350                 return -EFAULT;
1351         return 0;
1352 }
1353
1354 static int compat_copy_entries_to_user(unsigned int total_size,
1355                                        struct xt_table *table,
1356                                        void __user *userptr)
1357 {
1358         struct xt_counters *counters;
1359         const struct xt_table_info *private = table->private;
1360         void __user *pos;
1361         unsigned int size;
1362         int ret = 0;
1363         unsigned int i = 0;
1364         struct arpt_entry *iter;
1365
1366         counters = alloc_counters(table);
1367         if (IS_ERR(counters))
1368                 return PTR_ERR(counters);
1369
1370         pos = userptr;
1371         size = total_size;
1372         xt_entry_foreach(iter, private->entries, total_size) {
1373                 ret = compat_copy_entry_to_user(iter, &pos,
1374                                                 &size, counters, i++);
1375                 if (ret != 0)
1376                         break;
1377         }
1378         vfree(counters);
1379         return ret;
1380 }
1381
1382 struct compat_arpt_get_entries {
1383         char name[XT_TABLE_MAXNAMELEN];
1384         compat_uint_t size;
1385         struct compat_arpt_entry entrytable[0];
1386 };
1387
1388 static int compat_get_entries(struct net *net,
1389                               struct compat_arpt_get_entries __user *uptr,
1390                               int *len)
1391 {
1392         int ret;
1393         struct compat_arpt_get_entries get;
1394         struct xt_table *t;
1395
1396         if (*len < sizeof(get))
1397                 return -EINVAL;
1398         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1399                 return -EFAULT;
1400         if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1401                 return -EINVAL;
1402
1403         get.name[sizeof(get.name) - 1] = '\0';
1404
1405         xt_compat_lock(NFPROTO_ARP);
1406         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1407         if (t) {
1408                 const struct xt_table_info *private = t->private;
1409                 struct xt_table_info info;
1410
1411                 ret = compat_table_info(private, &info);
1412                 if (!ret && get.size == info.size) {
1413                         ret = compat_copy_entries_to_user(private->size,
1414                                                           t, uptr->entrytable);
1415                 } else if (!ret)
1416                         ret = -EAGAIN;
1417
1418                 xt_compat_flush_offsets(NFPROTO_ARP);
1419                 module_put(t->me);
1420                 xt_table_unlock(t);
1421         } else
1422                 ret = -ENOENT;
1423
1424         xt_compat_unlock(NFPROTO_ARP);
1425         return ret;
1426 }
1427
1428 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1429
1430 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1431                                   int *len)
1432 {
1433         int ret;
1434
1435         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1436                 return -EPERM;
1437
1438         switch (cmd) {
1439         case ARPT_SO_GET_INFO:
1440                 ret = get_info(sock_net(sk), user, len, 1);
1441                 break;
1442         case ARPT_SO_GET_ENTRIES:
1443                 ret = compat_get_entries(sock_net(sk), user, len);
1444                 break;
1445         default:
1446                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1447         }
1448         return ret;
1449 }
1450 #endif
1451
1452 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1453 {
1454         int ret;
1455
1456         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1457                 return -EPERM;
1458
1459         switch (cmd) {
1460         case ARPT_SO_SET_REPLACE:
1461                 ret = do_replace(sock_net(sk), user, len);
1462                 break;
1463
1464         case ARPT_SO_SET_ADD_COUNTERS:
1465                 ret = do_add_counters(sock_net(sk), user, len, 0);
1466                 break;
1467
1468         default:
1469                 ret = -EINVAL;
1470         }
1471
1472         return ret;
1473 }
1474
1475 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1476 {
1477         int ret;
1478
1479         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1480                 return -EPERM;
1481
1482         switch (cmd) {
1483         case ARPT_SO_GET_INFO:
1484                 ret = get_info(sock_net(sk), user, len, 0);
1485                 break;
1486
1487         case ARPT_SO_GET_ENTRIES:
1488                 ret = get_entries(sock_net(sk), user, len);
1489                 break;
1490
1491         case ARPT_SO_GET_REVISION_TARGET: {
1492                 struct xt_get_revision rev;
1493
1494                 if (*len != sizeof(rev)) {
1495                         ret = -EINVAL;
1496                         break;
1497                 }
1498                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1499                         ret = -EFAULT;
1500                         break;
1501                 }
1502                 rev.name[sizeof(rev.name)-1] = 0;
1503
1504                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1505                                                          rev.revision, 1, &ret),
1506                                         "arpt_%s", rev.name);
1507                 break;
1508         }
1509
1510         default:
1511                 ret = -EINVAL;
1512         }
1513
1514         return ret;
1515 }
1516
1517 static void __arpt_unregister_table(struct xt_table *table)
1518 {
1519         struct xt_table_info *private;
1520         void *loc_cpu_entry;
1521         struct module *table_owner = table->me;
1522         struct arpt_entry *iter;
1523
1524         private = xt_unregister_table(table);
1525
1526         /* Decrease module usage counts and free resources */
1527         loc_cpu_entry = private->entries;
1528         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1529                 cleanup_entry(iter);
1530         if (private->number > private->initial_entries)
1531                 module_put(table_owner);
1532         xt_free_table_info(private);
1533 }
1534
1535 int arpt_register_table(struct net *net,
1536                         const struct xt_table *table,
1537                         const struct arpt_replace *repl,
1538                         const struct nf_hook_ops *ops,
1539                         struct xt_table **res)
1540 {
1541         int ret;
1542         struct xt_table_info *newinfo;
1543         struct xt_table_info bootstrap = {0};
1544         void *loc_cpu_entry;
1545         struct xt_table *new_table;
1546
1547         newinfo = xt_alloc_table_info(repl->size);
1548         if (!newinfo)
1549                 return -ENOMEM;
1550
1551         loc_cpu_entry = newinfo->entries;
1552         memcpy(loc_cpu_entry, repl->entries, repl->size);
1553
1554         ret = translate_table(newinfo, loc_cpu_entry, repl);
1555         if (ret != 0)
1556                 goto out_free;
1557
1558         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1559         if (IS_ERR(new_table)) {
1560                 ret = PTR_ERR(new_table);
1561                 goto out_free;
1562         }
1563
1564         /* set res now, will see skbs right after nf_register_net_hooks */
1565         WRITE_ONCE(*res, new_table);
1566
1567         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1568         if (ret != 0) {
1569                 __arpt_unregister_table(new_table);
1570                 *res = NULL;
1571         }
1572
1573         return ret;
1574
1575 out_free:
1576         xt_free_table_info(newinfo);
1577         return ret;
1578 }
1579
1580 void arpt_unregister_table(struct net *net, struct xt_table *table,
1581                            const struct nf_hook_ops *ops)
1582 {
1583         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1584         __arpt_unregister_table(table);
1585 }
1586
1587 /* The built-in targets: standard (NULL) and error. */
1588 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1589         {
1590                 .name             = XT_STANDARD_TARGET,
1591                 .targetsize       = sizeof(int),
1592                 .family           = NFPROTO_ARP,
1593 #ifdef CONFIG_COMPAT
1594                 .compatsize       = sizeof(compat_int_t),
1595                 .compat_from_user = compat_standard_from_user,
1596                 .compat_to_user   = compat_standard_to_user,
1597 #endif
1598         },
1599         {
1600                 .name             = XT_ERROR_TARGET,
1601                 .target           = arpt_error,
1602                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1603                 .family           = NFPROTO_ARP,
1604         },
1605 };
1606
1607 static struct nf_sockopt_ops arpt_sockopts = {
1608         .pf             = PF_INET,
1609         .set_optmin     = ARPT_BASE_CTL,
1610         .set_optmax     = ARPT_SO_SET_MAX+1,
1611         .set            = do_arpt_set_ctl,
1612 #ifdef CONFIG_COMPAT
1613         .compat_set     = compat_do_arpt_set_ctl,
1614 #endif
1615         .get_optmin     = ARPT_BASE_CTL,
1616         .get_optmax     = ARPT_SO_GET_MAX+1,
1617         .get            = do_arpt_get_ctl,
1618 #ifdef CONFIG_COMPAT
1619         .compat_get     = compat_do_arpt_get_ctl,
1620 #endif
1621         .owner          = THIS_MODULE,
1622 };
1623
1624 static int __net_init arp_tables_net_init(struct net *net)
1625 {
1626         return xt_proto_init(net, NFPROTO_ARP);
1627 }
1628
1629 static void __net_exit arp_tables_net_exit(struct net *net)
1630 {
1631         xt_proto_fini(net, NFPROTO_ARP);
1632 }
1633
1634 static struct pernet_operations arp_tables_net_ops = {
1635         .init = arp_tables_net_init,
1636         .exit = arp_tables_net_exit,
1637 };
1638
1639 static int __init arp_tables_init(void)
1640 {
1641         int ret;
1642
1643         ret = register_pernet_subsys(&arp_tables_net_ops);
1644         if (ret < 0)
1645                 goto err1;
1646
1647         /* No one else will be downing sem now, so we won't sleep */
1648         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1649         if (ret < 0)
1650                 goto err2;
1651
1652         /* Register setsockopt */
1653         ret = nf_register_sockopt(&arpt_sockopts);
1654         if (ret < 0)
1655                 goto err4;
1656
1657         pr_info("arp_tables: (C) 2002 David S. Miller\n");
1658         return 0;
1659
1660 err4:
1661         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1662 err2:
1663         unregister_pernet_subsys(&arp_tables_net_ops);
1664 err1:
1665         return ret;
1666 }
1667
1668 static void __exit arp_tables_fini(void)
1669 {
1670         nf_unregister_sockopt(&arpt_sockopts);
1671         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1672         unregister_pernet_subsys(&arp_tables_net_ops);
1673 }
1674
1675 EXPORT_SYMBOL(arpt_register_table);
1676 EXPORT_SYMBOL(arpt_unregister_table);
1677 EXPORT_SYMBOL(arpt_do_table);
1678
1679 module_init(arp_tables_init);
1680 module_exit(arp_tables_fini);