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 ([email protected])
   9  * Copyright (C) 2006-2009 Patrick McHardy <[email protected]>
  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 <[email protected]>");
  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 = READ_ONCE(table->private); /* Address dependency. */
 206         cpu     = smp_processor_id();
 207         table_base = private->entries;
 208         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 209
 210         /* No TEE support for arptables, so no need to switch to alternate
 211          * stack.  All targets that reenter must return absolute verdicts.
 212          */
 213         e = get_entry(table_base, private->hook_entry[hook]);
 214
 215         acpar.state   = state;
 216         acpar.hotdrop = false;
 217
 218         arp = arp_hdr(skb);
 219         do {
 220                 const struct xt_entry_target *t;
 221                 struct xt_counters *counter;
 222
 223                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 224                         e = arpt_next_entry(e);
 225                         continue;
 226                 }
 227
 228                 counter = xt_get_this_cpu_counter(&e->counters);
 229                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 230
 231                 t = arpt_get_target_c(e);
 232
 233                 /* Standard target? */
 234                 if (!t->u.kernel.target->target) {
 235                         int v;
 236
 237                         v = ((struct xt_standard_target *)t)->verdict;
 238                         if (v < 0) {
 239                                 /* Pop from stack? */
 240                                 if (v != XT_RETURN) {
 241                                         verdict = (unsigned int)(-v) - 1;
 242                                         break;
 243                                 }
 244                                 if (stackidx == 0) {
 245                                         e = get_entry(table_base,
 246                                                       private->underflow[hook]);
 247                                 } else {
 248                                         e = jumpstack[--stackidx];
 249                                         e = arpt_next_entry(e);
 250                                 }
 251                                 continue;
 252                         }
 253                         if (table_base + v
 254                             != arpt_next_entry(e)) {
 255                                 if (unlikely(stackidx >= private->stacksize)) {
 256                                         verdict = NF_DROP;
 257                                         break;
 258                                 }
 259                                 jumpstack[stackidx++] = e;
 260                         }
 261
 262                         e = get_entry(table_base, v);
 263                         continue;
 264                 }
 265
 266                 acpar.target   = t->u.kernel.target;
 267                 acpar.targinfo = t->data;
 268                 verdict = t->u.kernel.target->target(skb, &acpar);
 269
 270                 if (verdict == XT_CONTINUE) {
 271                         /* Target might have changed stuff. */
 272                         arp = arp_hdr(skb);
 273                         e = arpt_next_entry(e);
 274                 } else {
 275                         /* Verdict */
 276                         break;
 277                 }
 278         } while (!acpar.hotdrop);
 279         xt_write_recseq_end(addend);
 280         local_bh_enable();
 281
 282         if (acpar.hotdrop)
 283                 return NF_DROP;
 284         else
 285                 return verdict;
 286 }
 287
 288 /* All zeroes == unconditional rule. */
 289 static inline bool unconditional(const struct arpt_entry *e)
 290 {
 291         static const struct arpt_arp uncond;
 292
 293         return e->target_offset == sizeof(struct arpt_entry) &&
 294                memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
 295 }
 296
 297 /* Figures out from what hook each rule can be called: returns 0 if
 298  * there are loops.  Puts hook bitmask in comefrom.
 299  */
 300 static int mark_source_chains(const struct xt_table_info *newinfo,
 301                               unsigned int valid_hooks, void *entry0,
 302                               unsigned int *offsets)
 303 {
 304         unsigned int hook;
 305
 306         /* No recursion; use packet counter to save back ptrs (reset
 307          * to 0 as we leave), and comefrom to save source hook bitmask.
 308          */
 309         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 310                 unsigned int pos = newinfo->hook_entry[hook];
 311                 struct arpt_entry *e = entry0 + pos;
 312
 313                 if (!(valid_hooks & (1 << hook)))
 314                         continue;
 315
 316                 /* Set initial back pointer. */
 317                 e->counters.pcnt = pos;
 318
 319                 for (;;) {
 320                         const struct xt_standard_target *t
 321                                 = (void *)arpt_get_target_c(e);
 322                         int visited = e->comefrom & (1 << hook);
 323
 324                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
 325                                 return 0;
 326
 327                         e->comefrom
 328                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 329
 330                         /* Unconditional return/END. */
 331                         if ((unconditional(e) &&
 332                              (strcmp(t->target.u.user.name,
 333                                      XT_STANDARD_TARGET) == 0) &&
 334                              t->verdict < 0) || visited) {
 335                                 unsigned int oldpos, size;
 336
 337                                 /* Return: backtrack through the last
 338                                  * big jump.
 339                                  */
 340                                 do {
 341                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 342                                         oldpos = pos;
 343                                         pos = e->counters.pcnt;
 344                                         e->counters.pcnt = 0;
 345
 346                                         /* We're at the start. */
 347                                         if (pos == oldpos)
 348                                                 goto next;
 349
 350                                         e = entry0 + pos;
 351                                 } while (oldpos == pos + e->next_offset);
 352
 353                                 /* Move along one */
 354                                 size = e->next_offset;
 355                                 e = entry0 + pos + size;
 356                                 if (pos + size >= newinfo->size)
 357                                         return 0;
 358                                 e->counters.pcnt = pos;
 359                                 pos += size;
 360                         } else {
 361                                 int newpos = t->verdict;
 362
 363                                 if (strcmp(t->target.u.user.name,
 364                                            XT_STANDARD_TARGET) == 0 &&
 365                                     newpos >= 0) {
 366                                         /* This a jump; chase it. */
 367                                         if (!xt_find_jump_offset(offsets, newpos,
 368                                                                  newinfo->number))
 369                                                 return 0;
 370                                 } else {
 371                                         /* ... this is a fallthru */
 372                                         newpos = pos + e->next_offset;
 373                                         if (newpos >= newinfo->size)
 374                                                 return 0;
 375                                 }
 376                                 e = entry0 + newpos;
 377                                 e->counters.pcnt = pos;
 378                                 pos = newpos;
 379                         }
 380                 }
 381 next:           ;
 382         }
 383         return 1;
 384 }
 385
 386 static inline int check_target(struct arpt_entry *e, const char *name)
 387 {
 388         struct xt_entry_target *t = arpt_get_target(e);
 389         struct xt_tgchk_param par = {
 390                 .table     = name,
 391                 .entryinfo = e,
 392                 .target    = t->u.kernel.target,
 393                 .targinfo  = t->data,
 394                 .hook_mask = e->comefrom,
 395                 .family    = NFPROTO_ARP,
 396         };
 397
 398         return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 399 }
 400
 401 static inline int
 402 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 403                  struct xt_percpu_counter_alloc_state *alloc_state)
 404 {
 405         struct xt_entry_target *t;
 406         struct xt_target *target;
 407         int ret;
 408
 409         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 410                 return -ENOMEM;
 411
 412         t = arpt_get_target(e);
 413         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 414                                         t->u.user.revision);
 415         if (IS_ERR(target)) {
 416                 ret = PTR_ERR(target);
 417                 goto out;
 418         }
 419         t->u.kernel.target = target;
 420
 421         ret = check_target(e, name);
 422         if (ret)
 423                 goto err;
 424         return 0;
 425 err:
 426         module_put(t->u.kernel.target->me);
 427 out:
 428         xt_percpu_counter_free(&e->counters);
 429
 430         return ret;
 431 }
 432
 433 static bool check_underflow(const struct arpt_entry *e)
 434 {
 435         const struct xt_entry_target *t;
 436         unsigned int verdict;
 437
 438         if (!unconditional(e))
 439                 return false;
 440         t = arpt_get_target_c(e);
 441         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 442                 return false;
 443         verdict = ((struct xt_standard_target *)t)->verdict;
 444         verdict = -verdict - 1;
 445         return verdict == NF_DROP || verdict == NF_ACCEPT;
 446 }
 447
 448 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 449                                              struct xt_table_info *newinfo,
 450                                              const unsigned char *base,
 451                                              const unsigned char *limit,
 452                                              const unsigned int *hook_entries,
 453                                              const unsigned int *underflows,
 454                                              unsigned int valid_hooks)
 455 {
 456         unsigned int h;
 457         int err;
 458
 459         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 460             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 461             (unsigned char *)e + e->next_offset > limit)
 462                 return -EINVAL;
 463
 464         if (e->next_offset
 465             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
 466                 return -EINVAL;
 467
 468         if (!arp_checkentry(&e->arp))
 469                 return -EINVAL;
 470
 471         err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 472                                      e->next_offset);
 473         if (err)
 474                 return err;
 475
 476         /* Check hooks & underflows */
 477         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 478                 if (!(valid_hooks & (1 << h)))
 479                         continue;
 480                 if ((unsigned char *)e - base == hook_entries[h])
 481                         newinfo->hook_entry[h] = hook_entries[h];
 482                 if ((unsigned char *)e - base == underflows[h]) {
 483                         if (!check_underflow(e))
 484                                 return -EINVAL;
 485
 486                         newinfo->underflow[h] = underflows[h];
 487                 }
 488         }
 489
 490         /* Clear counters and comefrom */
 491         e->counters = ((struct xt_counters) { 0, 0 });
 492         e->comefrom = 0;
 493         return 0;
 494 }
 495
 496 static inline void cleanup_entry(struct arpt_entry *e)
 497 {
 498         struct xt_tgdtor_param par;
 499         struct xt_entry_target *t;
 500
 501         t = arpt_get_target(e);
 502         par.target   = t->u.kernel.target;
 503         par.targinfo = t->data;
 504         par.family   = NFPROTO_ARP;
 505         if (par.target->destroy != NULL)
 506                 par.target->destroy(&par);
 507         module_put(par.target->me);
 508         xt_percpu_counter_free(&e->counters);
 509 }
 510
 511 /* Checks and translates the user-supplied table segment (held in
 512  * newinfo).
 513  */
 514 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 515                            const struct arpt_replace *repl)
 516 {
 517         struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 518         struct arpt_entry *iter;
 519         unsigned int *offsets;
 520         unsigned int i;
 521         int ret = 0;
 522
 523         newinfo->size = repl->size;
 524         newinfo->number = repl->num_entries;
 525
 526         /* Init all hooks to impossible value. */
 527         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 528                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 529                 newinfo->underflow[i] = 0xFFFFFFFF;
 530         }
 531
 532         offsets = xt_alloc_entry_offsets(newinfo->number);
 533         if (!offsets)
 534                 return -ENOMEM;
 535         i = 0;
 536
 537         /* Walk through entries, checking offsets. */
 538         xt_entry_foreach(iter, entry0, newinfo->size) {
 539                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 540                                                  entry0 + repl->size,
 541                                                  repl->hook_entry,
 542                                                  repl->underflow,
 543                                                  repl->valid_hooks);
 544                 if (ret != 0)
 545                         goto out_free;
 546                 if (i < repl->num_entries)
 547                         offsets[i] = (void *)iter - entry0;
 548                 ++i;
 549                 if (strcmp(arpt_get_target(iter)->u.user.name,
 550                     XT_ERROR_TARGET) == 0)
 551                         ++newinfo->stacksize;
 552         }
 553
 554         ret = -EINVAL;
 555         if (i != repl->num_entries)
 556                 goto out_free;
 557
 558         ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
 559         if (ret)
 560                 goto out_free;
 561
 562         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 563                 ret = -ELOOP;
 564                 goto out_free;
 565         }
 566         kvfree(offsets);
 567
 568         /* Finally, each sanity check must pass */
 569         i = 0;
 570         xt_entry_foreach(iter, entry0, newinfo->size) {
 571                 ret = find_check_entry(iter, repl->name, repl->size,
 572                                        &alloc_state);
 573                 if (ret != 0)
 574                         break;
 575                 ++i;
 576         }
 577
 578         if (ret != 0) {
 579                 xt_entry_foreach(iter, entry0, newinfo->size) {
 580                         if (i-- == 0)
 581                                 break;
 582                         cleanup_entry(iter);
 583                 }
 584                 return ret;
 585         }
 586
 587         return ret;
 588  out_free:
 589         kvfree(offsets);
 590         return ret;
 591 }
 592
 593 static void get_counters(const struct xt_table_info *t,
 594                          struct xt_counters counters[])
 595 {
 596         struct arpt_entry *iter;
 597         unsigned int cpu;
 598         unsigned int i;
 599
 600         for_each_possible_cpu(cpu) {
 601                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 602
 603                 i = 0;
 604                 xt_entry_foreach(iter, t->entries, t->size) {
 605                         struct xt_counters *tmp;
 606                         u64 bcnt, pcnt;
 607                         unsigned int start;
 608
 609                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 610                         do {
 611                                 start = read_seqcount_begin(s);
 612                                 bcnt = tmp->bcnt;
 613                                 pcnt = tmp->pcnt;
 614                         } while (read_seqcount_retry(s, start));
 615
 616                         ADD_COUNTER(counters[i], bcnt, pcnt);
 617                         ++i;
 618                         cond_resched();
 619                 }
 620         }
 621 }
 622
 623 static void get_old_counters(const struct xt_table_info *t,
 624                              struct xt_counters counters[])
 625 {
 626         struct arpt_entry *iter;
 627         unsigned int cpu, i;
 628
 629         for_each_possible_cpu(cpu) {
 630                 i = 0;
 631                 xt_entry_foreach(iter, t->entries, t->size) {
 632                         struct xt_counters *tmp;
 633
 634                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 635                         ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
 636                         ++i;
 637                 }
 638                 cond_resched();
 639         }
 640 }
 641
 642 static struct xt_counters *alloc_counters(const struct xt_table *table)
 643 {
 644         unsigned int countersize;
 645         struct xt_counters *counters;
 646         const struct xt_table_info *private = table->private;
 647
 648         /* We need atomic snapshot of counters: rest doesn't change
 649          * (other than comefrom, which userspace doesn't care
 650          * about).
 651          */
 652         countersize = sizeof(struct xt_counters) * private->number;
 653         counters = vzalloc(countersize);
 654
 655         if (counters == NULL)
 656                 return ERR_PTR(-ENOMEM);
 657
 658         get_counters(private, counters);
 659
 660         return counters;
 661 }
 662
 663 static int copy_entries_to_user(unsigned int total_size,
 664                                 const struct xt_table *table,
 665                                 void __user *userptr)
 666 {
 667         unsigned int off, num;
 668         const struct arpt_entry *e;
 669         struct xt_counters *counters;
 670         struct xt_table_info *private = table->private;
 671         int ret = 0;
 672         void *loc_cpu_entry;
 673
 674         counters = alloc_counters(table);
 675         if (IS_ERR(counters))
 676                 return PTR_ERR(counters);
 677
 678         loc_cpu_entry = private->entries;
 679
 680         /* FIXME: use iterator macros --RR */
 681         /* ... then go back and fix counters and names */
 682         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 683                 const struct xt_entry_target *t;
 684
 685                 e = loc_cpu_entry + off;
 686                 if (copy_to_user(userptr + off, e, sizeof(*e))) {
 687                         ret = -EFAULT;
 688                         goto free_counters;
 689                 }
 690                 if (copy_to_user(userptr + off
 691                                  + offsetof(struct arpt_entry, counters),
 692                                  &counters[num],
 693                                  sizeof(counters[num])) != 0) {
 694                         ret = -EFAULT;
 695                         goto free_counters;
 696                 }
 697
 698                 t = arpt_get_target_c(e);
 699                 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
 700                         ret = -EFAULT;
 701                         goto free_counters;
 702                 }
 703         }
 704
 705  free_counters:
 706         vfree(counters);
 707         return ret;
 708 }
 709
 710 #ifdef CONFIG_COMPAT
 711 static void compat_standard_from_user(void *dst, const void *src)
 712 {
 713         int v = *(compat_int_t *)src;
 714
 715         if (v > 0)
 716                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 717         memcpy(dst, &v, sizeof(v));
 718 }
 719
 720 static int compat_standard_to_user(void __user *dst, const void *src)
 721 {
 722         compat_int_t cv = *(int *)src;
 723
 724         if (cv > 0)
 725                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 726         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 727 }
 728
 729 static int compat_calc_entry(const struct arpt_entry *e,
 730                              const struct xt_table_info *info,
 731                              const void *base, struct xt_table_info *newinfo)
 732 {
 733         const struct xt_entry_target *t;
 734         unsigned int entry_offset;
 735         int off, i, ret;
 736
 737         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 738         entry_offset = (void *)e - base;
 739
 740         t = arpt_get_target_c(e);
 741         off += xt_compat_target_offset(t->u.kernel.target);
 742         newinfo->size -= off;
 743         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 744         if (ret)
 745                 return ret;
 746
 747         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 748                 if (info->hook_entry[i] &&
 749                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 750                         newinfo->hook_entry[i] -= off;
 751                 if (info->underflow[i] &&
 752                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 753                         newinfo->underflow[i] -= off;
 754         }
 755         return 0;
 756 }
 757
 758 static int compat_table_info(const struct xt_table_info *info,
 759                              struct xt_table_info *newinfo)
 760 {
 761         struct arpt_entry *iter;
 762         const void *loc_cpu_entry;
 763         int ret;
 764
 765         if (!newinfo || !info)
 766                 return -EINVAL;
 767
 768         /* we dont care about newinfo->entries */
 769         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 770         newinfo->initial_entries = 0;
 771         loc_cpu_entry = info->entries;
 772         ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
 773         if (ret)
 774                 return ret;
 775         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 776                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 777                 if (ret != 0)
 778                         return ret;
 779         }
 780         return 0;
 781 }
 782 #endif
 783
 784 static int get_info(struct net *net, void __user *user,
 785                     const int *len, int compat)
 786 {
 787         char name[XT_TABLE_MAXNAMELEN];
 788         struct xt_table *t;
 789         int ret;
 790
 791         if (*len != sizeof(struct arpt_getinfo))
 792                 return -EINVAL;
 793
 794         if (copy_from_user(name, user, sizeof(name)) != 0)
 795                 return -EFAULT;
 796
 797         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 798 #ifdef CONFIG_COMPAT
 799         if (compat)
 800                 xt_compat_lock(NFPROTO_ARP);
 801 #endif
 802         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 803         if (!IS_ERR(t)) {
 804                 struct arpt_getinfo info;
 805                 const struct xt_table_info *private = t->private;
 806 #ifdef CONFIG_COMPAT
 807                 struct xt_table_info tmp;
 808
 809                 if (compat) {
 810                         ret = compat_table_info(private, &tmp);
 811                         xt_compat_flush_offsets(NFPROTO_ARP);
 812                         private = &tmp;
 813                 }
 814 #endif
 815                 memset(&info, 0, sizeof(info));
 816                 info.valid_hooks = t->valid_hooks;
 817                 memcpy(info.hook_entry, private->hook_entry,
 818                        sizeof(info.hook_entry));
 819                 memcpy(info.underflow, private->underflow,
 820                        sizeof(info.underflow));
 821                 info.num_entries = private->number;
 822                 info.size = private->size;
 823                 strcpy(info.name, name);
 824
 825                 if (copy_to_user(user, &info, *len) != 0)
 826                         ret = -EFAULT;
 827                 else
 828                         ret = 0;
 829                 xt_table_unlock(t);
 830                 module_put(t->me);
 831         } else
 832                 ret = PTR_ERR(t);
 833 #ifdef CONFIG_COMPAT
 834         if (compat)
 835                 xt_compat_unlock(NFPROTO_ARP);
 836 #endif
 837         return ret;
 838 }
 839
 840 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 841                        const int *len)
 842 {
 843         int ret;
 844         struct arpt_get_entries get;
 845         struct xt_table *t;
 846
 847         if (*len < sizeof(get))
 848                 return -EINVAL;
 849         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 850                 return -EFAULT;
 851         if (*len != sizeof(struct arpt_get_entries) + get.size)
 852                 return -EINVAL;
 853
 854         get.name[sizeof(get.name) - 1] = '\0';
 855
 856         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 857         if (!IS_ERR(t)) {
 858                 const struct xt_table_info *private = t->private;
 859
 860                 if (get.size == private->size)
 861                         ret = copy_entries_to_user(private->size,
 862                                                    t, uptr->entrytable);
 863                 else
 864                         ret = -EAGAIN;
 865
 866                 module_put(t->me);
 867                 xt_table_unlock(t);
 868         } else
 869                 ret = PTR_ERR(t);
 870
 871         return ret;
 872 }
 873
 874 static int __do_replace(struct net *net, const char *name,
 875                         unsigned int valid_hooks,
 876                         struct xt_table_info *newinfo,
 877                         unsigned int num_counters,
 878                         void __user *counters_ptr)
 879 {
 880         int ret;
 881         struct xt_table *t;
 882         struct xt_table_info *oldinfo;
 883         struct xt_counters *counters;
 884         void *loc_cpu_old_entry;
 885         struct arpt_entry *iter;
 886
 887         ret = 0;
 888         counters = xt_counters_alloc(num_counters);
 889         if (!counters) {
 890                 ret = -ENOMEM;
 891                 goto out;
 892         }
 893
 894         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 895         if (IS_ERR(t)) {
 896                 ret = PTR_ERR(t);
 897                 goto free_newinfo_counters_untrans;
 898         }
 899
 900         /* You lied! */
 901         if (valid_hooks != t->valid_hooks) {
 902                 ret = -EINVAL;
 903                 goto put_module;
 904         }
 905
 906         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
 907         if (!oldinfo)
 908                 goto put_module;
 909
 910         /* Update module usage count based on number of rules */
 911         if ((oldinfo->number > oldinfo->initial_entries) ||
 912             (newinfo->number <= oldinfo->initial_entries))
 913                 module_put(t->me);
 914         if ((oldinfo->number > oldinfo->initial_entries) &&
 915             (newinfo->number <= oldinfo->initial_entries))
 916                 module_put(t->me);
 917
 918         xt_table_unlock(t);
 919
 920         get_old_counters(oldinfo, counters);
 921
 922         /* Decrease module usage counts and free resource */
 923         loc_cpu_old_entry = oldinfo->entries;
 924         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
 925                 cleanup_entry(iter);
 926
 927         xt_free_table_info(oldinfo);
 928         if (copy_to_user(counters_ptr, counters,
 929                          sizeof(struct xt_counters) * num_counters) != 0) {
 930                 /* Silent error, can't fail, new table is already in place */
 931                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
 932         }
 933         vfree(counters);
 934         return ret;
 935
 936  put_module:
 937         module_put(t->me);
 938         xt_table_unlock(t);
 939  free_newinfo_counters_untrans:
 940         vfree(counters);
 941  out:
 942         return ret;
 943 }
 944
 945 static int do_replace(struct net *net, const void __user *user,
 946                       unsigned int len)
 947 {
 948         int ret;
 949         struct arpt_replace tmp;
 950         struct xt_table_info *newinfo;
 951         void *loc_cpu_entry;
 952         struct arpt_entry *iter;
 953
 954         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 955                 return -EFAULT;
 956
 957         /* overflow check */
 958         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 959                 return -ENOMEM;
 960         if (tmp.num_counters == 0)
 961                 return -EINVAL;
 962
 963         tmp.name[sizeof(tmp.name)-1] = 0;
 964
 965         newinfo = xt_alloc_table_info(tmp.size);
 966         if (!newinfo)
 967                 return -ENOMEM;
 968
 969         loc_cpu_entry = newinfo->entries;
 970         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 971                            tmp.size) != 0) {
 972                 ret = -EFAULT;
 973                 goto free_newinfo;
 974         }
 975
 976         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
 977         if (ret != 0)
 978                 goto free_newinfo;
 979
 980         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
 981                            tmp.num_counters, tmp.counters);
 982         if (ret)
 983                 goto free_newinfo_untrans;
 984         return 0;
 985
 986  free_newinfo_untrans:
 987         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
 988                 cleanup_entry(iter);
 989  free_newinfo:
 990         xt_free_table_info(newinfo);
 991         return ret;
 992 }
 993
 994 static int do_add_counters(struct net *net, const void __user *user,
 995                            unsigned int len, int compat)
 996 {
 997         unsigned int i;
 998         struct xt_counters_info tmp;
 999         struct xt_counters *paddc;
1000         struct xt_table *t;
1001         const struct xt_table_info *private;
1002         int ret = 0;
1003         struct arpt_entry *iter;
1004         unsigned int addend;
1005
1006         paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1007         if (IS_ERR(paddc))
1008                 return PTR_ERR(paddc);
1009
1010         t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1011         if (IS_ERR(t)) {
1012                 ret = PTR_ERR(t);
1013                 goto free;
1014         }
1015
1016         local_bh_disable();
1017         private = t->private;
1018         if (private->number != tmp.num_counters) {
1019                 ret = -EINVAL;
1020                 goto unlock_up_free;
1021         }
1022
1023         i = 0;
1024
1025         addend = xt_write_recseq_begin();
1026         xt_entry_foreach(iter,  private->entries, private->size) {
1027                 struct xt_counters *tmp;
1028
1029                 tmp = xt_get_this_cpu_counter(&iter->counters);
1030                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1031                 ++i;
1032         }
1033         xt_write_recseq_end(addend);
1034  unlock_up_free:
1035         local_bh_enable();
1036         xt_table_unlock(t);
1037         module_put(t->me);
1038  free:
1039         vfree(paddc);
1040
1041         return ret;
1042 }
1043
1044 #ifdef CONFIG_COMPAT
1045 struct compat_arpt_replace {
1046         char                            name[XT_TABLE_MAXNAMELEN];
1047         u32                             valid_hooks;
1048         u32                             num_entries;
1049         u32                             size;
1050         u32                             hook_entry[NF_ARP_NUMHOOKS];
1051         u32                             underflow[NF_ARP_NUMHOOKS];
1052         u32                             num_counters;
1053         compat_uptr_t                   counters;
1054         struct compat_arpt_entry        entries[0];
1055 };
1056
1057 static inline void compat_release_entry(struct compat_arpt_entry *e)
1058 {
1059         struct xt_entry_target *t;
1060
1061         t = compat_arpt_get_target(e);
1062         module_put(t->u.kernel.target->me);
1063 }
1064
1065 static int
1066 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1067                                   struct xt_table_info *newinfo,
1068                                   unsigned int *size,
1069                                   const unsigned char *base,
1070                                   const unsigned char *limit)
1071 {
1072         struct xt_entry_target *t;
1073         struct xt_target *target;
1074         unsigned int entry_offset;
1075         int ret, off;
1076
1077         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1078             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1079             (unsigned char *)e + e->next_offset > limit)
1080                 return -EINVAL;
1081
1082         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1083                              sizeof(struct compat_xt_entry_target))
1084                 return -EINVAL;
1085
1086         if (!arp_checkentry(&e->arp))
1087                 return -EINVAL;
1088
1089         ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1090                                             e->next_offset);
1091         if (ret)
1092                 return ret;
1093
1094         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1095         entry_offset = (void *)e - (void *)base;
1096
1097         t = compat_arpt_get_target(e);
1098         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1099                                         t->u.user.revision);
1100         if (IS_ERR(target)) {
1101                 ret = PTR_ERR(target);
1102                 goto out;
1103         }
1104         t->u.kernel.target = target;
1105
1106         off += xt_compat_target_offset(target);
1107         *size += off;
1108         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1109         if (ret)
1110                 goto release_target;
1111
1112         return 0;
1113
1114 release_target:
1115         module_put(t->u.kernel.target->me);
1116 out:
1117         return ret;
1118 }
1119
1120 static void
1121 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1122                             unsigned int *size,
1123                             struct xt_table_info *newinfo, unsigned char *base)
1124 {
1125         struct xt_entry_target *t;
1126         struct arpt_entry *de;
1127         unsigned int origsize;
1128         int h;
1129
1130         origsize = *size;
1131         de = *dstptr;
1132         memcpy(de, e, sizeof(struct arpt_entry));
1133         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1134
1135         *dstptr += sizeof(struct arpt_entry);
1136         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1137
1138         de->target_offset = e->target_offset - (origsize - *size);
1139         t = compat_arpt_get_target(e);
1140         xt_compat_target_from_user(t, dstptr, size);
1141
1142         de->next_offset = e->next_offset - (origsize - *size);
1143         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1144                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1145                         newinfo->hook_entry[h] -= origsize - *size;
1146                 if ((unsigned char *)de - base < newinfo->underflow[h])
1147                         newinfo->underflow[h] -= origsize - *size;
1148         }
1149 }
1150
1151 static int translate_compat_table(struct xt_table_info **pinfo,
1152                                   void **pentry0,
1153                                   const struct compat_arpt_replace *compatr)
1154 {
1155         unsigned int i, j;
1156         struct xt_table_info *newinfo, *info;
1157         void *pos, *entry0, *entry1;
1158         struct compat_arpt_entry *iter0;
1159         struct arpt_replace repl;
1160         unsigned int size;
1161         int ret;
1162
1163         info = *pinfo;
1164         entry0 = *pentry0;
1165         size = compatr->size;
1166         info->number = compatr->num_entries;
1167
1168         j = 0;
1169         xt_compat_lock(NFPROTO_ARP);
1170         ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1171         if (ret)
1172                 goto out_unlock;
1173         /* Walk through entries, checking offsets. */
1174         xt_entry_foreach(iter0, entry0, compatr->size) {
1175                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1176                                                         entry0,
1177                                                         entry0 + compatr->size);
1178                 if (ret != 0)
1179                         goto out_unlock;
1180                 ++j;
1181         }
1182
1183         ret = -EINVAL;
1184         if (j != compatr->num_entries)
1185                 goto out_unlock;
1186
1187         ret = -ENOMEM;
1188         newinfo = xt_alloc_table_info(size);
1189         if (!newinfo)
1190                 goto out_unlock;
1191
1192         newinfo->number = compatr->num_entries;
1193         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1194                 newinfo->hook_entry[i] = compatr->hook_entry[i];
1195                 newinfo->underflow[i] = compatr->underflow[i];
1196         }
1197         entry1 = newinfo->entries;
1198         pos = entry1;
1199         size = compatr->size;
1200         xt_entry_foreach(iter0, entry0, compatr->size)
1201                 compat_copy_entry_from_user(iter0, &pos, &size,
1202                                             newinfo, entry1);
1203
1204         /* all module references in entry0 are now gone */
1205
1206         xt_compat_flush_offsets(NFPROTO_ARP);
1207         xt_compat_unlock(NFPROTO_ARP);
1208
1209         memcpy(&repl, compatr, sizeof(*compatr));
1210
1211         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1212                 repl.hook_entry[i] = newinfo->hook_entry[i];
1213                 repl.underflow[i] = newinfo->underflow[i];
1214         }
1215
1216         repl.num_counters = 0;
1217         repl.counters = NULL;
1218         repl.size = newinfo->size;
1219         ret = translate_table(newinfo, entry1, &repl);
1220         if (ret)
1221                 goto free_newinfo;
1222
1223         *pinfo = newinfo;
1224         *pentry0 = entry1;
1225         xt_free_table_info(info);
1226         return 0;
1227
1228 free_newinfo:
1229         xt_free_table_info(newinfo);
1230         return ret;
1231 out_unlock:
1232         xt_compat_flush_offsets(NFPROTO_ARP);
1233         xt_compat_unlock(NFPROTO_ARP);
1234         xt_entry_foreach(iter0, entry0, compatr->size) {
1235                 if (j-- == 0)
1236                         break;
1237                 compat_release_entry(iter0);
1238         }
1239         return ret;
1240 }
1241
1242 static int compat_do_replace(struct net *net, void __user *user,
1243                              unsigned int len)
1244 {
1245         int ret;
1246         struct compat_arpt_replace tmp;
1247         struct xt_table_info *newinfo;
1248         void *loc_cpu_entry;
1249         struct arpt_entry *iter;
1250
1251         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1252                 return -EFAULT;
1253
1254         /* overflow check */
1255         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1256                 return -ENOMEM;
1257         if (tmp.num_counters == 0)
1258                 return -EINVAL;
1259
1260         tmp.name[sizeof(tmp.name)-1] = 0;
1261
1262         newinfo = xt_alloc_table_info(tmp.size);
1263         if (!newinfo)
1264                 return -ENOMEM;
1265
1266         loc_cpu_entry = newinfo->entries;
1267         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1268                 ret = -EFAULT;
1269                 goto free_newinfo;
1270         }
1271
1272         ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1273         if (ret != 0)
1274                 goto free_newinfo;
1275
1276         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1277                            tmp.num_counters, compat_ptr(tmp.counters));
1278         if (ret)
1279                 goto free_newinfo_untrans;
1280         return 0;
1281
1282  free_newinfo_untrans:
1283         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1284                 cleanup_entry(iter);
1285  free_newinfo:
1286         xt_free_table_info(newinfo);
1287         return ret;
1288 }
1289
1290 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1291                                   unsigned int len)
1292 {
1293         int ret;
1294
1295         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1296                 return -EPERM;
1297
1298         switch (cmd) {
1299         case ARPT_SO_SET_REPLACE:
1300                 ret = compat_do_replace(sock_net(sk), user, len);
1301                 break;
1302
1303         case ARPT_SO_SET_ADD_COUNTERS:
1304                 ret = do_add_counters(sock_net(sk), user, len, 1);
1305                 break;
1306
1307         default:
1308                 ret = -EINVAL;
1309         }
1310
1311         return ret;
1312 }
1313
1314 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1315                                      compat_uint_t *size,
1316                                      struct xt_counters *counters,
1317                                      unsigned int i)
1318 {
1319         struct xt_entry_target *t;
1320         struct compat_arpt_entry __user *ce;
1321         u_int16_t target_offset, next_offset;
1322         compat_uint_t origsize;
1323         int ret;
1324
1325         origsize = *size;
1326         ce = *dstptr;
1327         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1328             copy_to_user(&ce->counters, &counters[i],
1329             sizeof(counters[i])) != 0)
1330                 return -EFAULT;
1331
1332         *dstptr += sizeof(struct compat_arpt_entry);
1333         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1334
1335         target_offset = e->target_offset - (origsize - *size);
1336
1337         t = arpt_get_target(e);
1338         ret = xt_compat_target_to_user(t, dstptr, size);
1339         if (ret)
1340                 return ret;
1341         next_offset = e->next_offset - (origsize - *size);
1342         if (put_user(target_offset, &ce->target_offset) != 0 ||
1343             put_user(next_offset, &ce->next_offset) != 0)
1344                 return -EFAULT;
1345         return 0;
1346 }
1347
1348 static int compat_copy_entries_to_user(unsigned int total_size,
1349                                        struct xt_table *table,
1350                                        void __user *userptr)
1351 {
1352         struct xt_counters *counters;
1353         const struct xt_table_info *private = table->private;
1354         void __user *pos;
1355         unsigned int size;
1356         int ret = 0;
1357         unsigned int i = 0;
1358         struct arpt_entry *iter;
1359
1360         counters = alloc_counters(table);
1361         if (IS_ERR(counters))
1362                 return PTR_ERR(counters);
1363
1364         pos = userptr;
1365         size = total_size;
1366         xt_entry_foreach(iter, private->entries, total_size) {
1367                 ret = compat_copy_entry_to_user(iter, &pos,
1368                                                 &size, counters, i++);
1369                 if (ret != 0)
1370                         break;
1371         }
1372         vfree(counters);
1373         return ret;
1374 }
1375
1376 struct compat_arpt_get_entries {
1377         char name[XT_TABLE_MAXNAMELEN];
1378         compat_uint_t size;
1379         struct compat_arpt_entry entrytable[0];
1380 };
1381
1382 static int compat_get_entries(struct net *net,
1383                               struct compat_arpt_get_entries __user *uptr,
1384                               int *len)
1385 {
1386         int ret;
1387         struct compat_arpt_get_entries get;
1388         struct xt_table *t;
1389
1390         if (*len < sizeof(get))
1391                 return -EINVAL;
1392         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1393                 return -EFAULT;
1394         if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1395                 return -EINVAL;
1396
1397         get.name[sizeof(get.name) - 1] = '\0';
1398
1399         xt_compat_lock(NFPROTO_ARP);
1400         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1401         if (!IS_ERR(t)) {
1402                 const struct xt_table_info *private = t->private;
1403                 struct xt_table_info info;
1404
1405                 ret = compat_table_info(private, &info);
1406                 if (!ret && get.size == info.size) {
1407                         ret = compat_copy_entries_to_user(private->size,
1408                                                           t, uptr->entrytable);
1409                 } else if (!ret)
1410                         ret = -EAGAIN;
1411
1412                 xt_compat_flush_offsets(NFPROTO_ARP);
1413                 module_put(t->me);
1414                 xt_table_unlock(t);
1415         } else
1416                 ret = PTR_ERR(t);
1417
1418         xt_compat_unlock(NFPROTO_ARP);
1419         return ret;
1420 }
1421
1422 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1423
1424 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1425                                   int *len)
1426 {
1427         int ret;
1428
1429         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1430                 return -EPERM;
1431
1432         switch (cmd) {
1433         case ARPT_SO_GET_INFO:
1434                 ret = get_info(sock_net(sk), user, len, 1);
1435                 break;
1436         case ARPT_SO_GET_ENTRIES:
1437                 ret = compat_get_entries(sock_net(sk), user, len);
1438                 break;
1439         default:
1440                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1441         }
1442         return ret;
1443 }
1444 #endif
1445
1446 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1447 {
1448         int ret;
1449
1450         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1451                 return -EPERM;
1452
1453         switch (cmd) {
1454         case ARPT_SO_SET_REPLACE:
1455                 ret = do_replace(sock_net(sk), user, len);
1456                 break;
1457
1458         case ARPT_SO_SET_ADD_COUNTERS:
1459                 ret = do_add_counters(sock_net(sk), user, len, 0);
1460                 break;
1461
1462         default:
1463                 ret = -EINVAL;
1464         }
1465
1466         return ret;
1467 }
1468
1469 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1470 {
1471         int ret;
1472
1473         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1474                 return -EPERM;
1475
1476         switch (cmd) {
1477         case ARPT_SO_GET_INFO:
1478                 ret = get_info(sock_net(sk), user, len, 0);
1479                 break;
1480
1481         case ARPT_SO_GET_ENTRIES:
1482                 ret = get_entries(sock_net(sk), user, len);
1483                 break;
1484
1485         case ARPT_SO_GET_REVISION_TARGET: {
1486                 struct xt_get_revision rev;
1487
1488                 if (*len != sizeof(rev)) {
1489                         ret = -EINVAL;
1490                         break;
1491                 }
1492                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1493                         ret = -EFAULT;
1494                         break;
1495                 }
1496                 rev.name[sizeof(rev.name)-1] = 0;
1497
1498                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1499                                                          rev.revision, 1, &ret),
1500                                         "arpt_%s", rev.name);
1501                 break;
1502         }
1503
1504         default:
1505                 ret = -EINVAL;
1506         }
1507
1508         return ret;
1509 }
1510
1511 static void __arpt_unregister_table(struct xt_table *table)
1512 {
1513         struct xt_table_info *private;
1514         void *loc_cpu_entry;
1515         struct module *table_owner = table->me;
1516         struct arpt_entry *iter;
1517
1518         private = xt_unregister_table(table);
1519
1520         /* Decrease module usage counts and free resources */
1521         loc_cpu_entry = private->entries;
1522         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1523                 cleanup_entry(iter);
1524         if (private->number > private->initial_entries)
1525                 module_put(table_owner);
1526         xt_free_table_info(private);
1527 }
1528
1529 int arpt_register_table(struct net *net,
1530                         const struct xt_table *table,
1531                         const struct arpt_replace *repl,
1532                         const struct nf_hook_ops *ops,
1533                         struct xt_table **res)
1534 {
1535         int ret;
1536         struct xt_table_info *newinfo;
1537         struct xt_table_info bootstrap = {0};
1538         void *loc_cpu_entry;
1539         struct xt_table *new_table;
1540
1541         newinfo = xt_alloc_table_info(repl->size);
1542         if (!newinfo)
1543                 return -ENOMEM;
1544
1545         loc_cpu_entry = newinfo->entries;
1546         memcpy(loc_cpu_entry, repl->entries, repl->size);
1547
1548         ret = translate_table(newinfo, loc_cpu_entry, repl);
1549         if (ret != 0)
1550                 goto out_free;
1551
1552         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1553         if (IS_ERR(new_table)) {
1554                 ret = PTR_ERR(new_table);
1555                 goto out_free;
1556         }
1557
1558         /* set res now, will see skbs right after nf_register_net_hooks */
1559         WRITE_ONCE(*res, new_table);
1560
1561         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1562         if (ret != 0) {
1563                 __arpt_unregister_table(new_table);
1564                 *res = NULL;
1565         }
1566
1567         return ret;
1568
1569 out_free:
1570         xt_free_table_info(newinfo);
1571         return ret;
1572 }
1573
1574 void arpt_unregister_table(struct net *net, struct xt_table *table,
1575                            const struct nf_hook_ops *ops)
1576 {
1577         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1578         __arpt_unregister_table(table);
1579 }
1580
1581 /* The built-in targets: standard (NULL) and error. */
1582 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1583         {
1584                 .name             = XT_STANDARD_TARGET,
1585                 .targetsize       = sizeof(int),
1586                 .family           = NFPROTO_ARP,
1587 #ifdef CONFIG_COMPAT
1588                 .compatsize       = sizeof(compat_int_t),
1589                 .compat_from_user = compat_standard_from_user,
1590                 .compat_to_user   = compat_standard_to_user,
1591 #endif
1592         },
1593         {
1594                 .name             = XT_ERROR_TARGET,
1595                 .target           = arpt_error,
1596                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1597                 .family           = NFPROTO_ARP,
1598         },
1599 };
1600
1601 static struct nf_sockopt_ops arpt_sockopts = {
1602         .pf             = PF_INET,
1603         .set_optmin     = ARPT_BASE_CTL,
1604         .set_optmax     = ARPT_SO_SET_MAX+1,
1605         .set            = do_arpt_set_ctl,
1606 #ifdef CONFIG_COMPAT
1607         .compat_set     = compat_do_arpt_set_ctl,
1608 #endif
1609         .get_optmin     = ARPT_BASE_CTL,
1610         .get_optmax     = ARPT_SO_GET_MAX+1,
1611         .get            = do_arpt_get_ctl,
1612 #ifdef CONFIG_COMPAT
1613         .compat_get     = compat_do_arpt_get_ctl,
1614 #endif
1615         .owner          = THIS_MODULE,
1616 };
1617
1618 static int __net_init arp_tables_net_init(struct net *net)
1619 {
1620         return xt_proto_init(net, NFPROTO_ARP);
1621 }
1622
1623 static void __net_exit arp_tables_net_exit(struct net *net)
1624 {
1625         xt_proto_fini(net, NFPROTO_ARP);
1626 }
1627
1628 static struct pernet_operations arp_tables_net_ops = {
1629         .init = arp_tables_net_init,
1630         .exit = arp_tables_net_exit,
1631 };
1632
1633 static int __init arp_tables_init(void)
1634 {
1635         int ret;
1636
1637         ret = register_pernet_subsys(&arp_tables_net_ops);
1638         if (ret < 0)
1639                 goto err1;
1640
1641         /* No one else will be downing sem now, so we won't sleep */
1642         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1643         if (ret < 0)
1644                 goto err2;
1645
1646         /* Register setsockopt */
1647         ret = nf_register_sockopt(&arpt_sockopts);
1648         if (ret < 0)
1649                 goto err4;
1650
1651         return 0;
1652
1653 err4:
1654         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1655 err2:
1656         unregister_pernet_subsys(&arp_tables_net_ops);
1657 err1:
1658         return ret;
1659 }
1660
1661 static void __exit arp_tables_fini(void)
1662 {
1663         nf_unregister_sockopt(&arpt_sockopts);
1664         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1665         unregister_pernet_subsys(&arp_tables_net_ops);
1666 }
1667
1668 EXPORT_SYMBOL(arpt_register_table);
1669 EXPORT_SYMBOL(arpt_unregister_table);
1670 EXPORT_SYMBOL(arpt_do_table);
1671
1672 module_init(arp_tables_init);
1673 module_exit(arp_tables_fini);