net/ipv4/netfilter/arp_tables.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Packet matching code for ARP packets.
   4  *
   5  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   6  *
   7  * Some ARP specific bits are:
   8  *
   9  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
  10  * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
  11  *
  12  */
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/kernel.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/capability.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/kmod.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/mutex.h>
  25 #include <linux/err.h>
  26 #include <net/compat.h>
  27 #include <net/sock.h>
  28 #include <linux/uaccess.h>
  29
  30 #include <linux/netfilter/x_tables.h>
  31 #include <linux/netfilter_arp/arp_tables.h>
  32 #include "../../netfilter/xt_repldata.h"
  33
  34 MODULE_LICENSE("GPL");
  35 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  36 MODULE_DESCRIPTION("arptables core");
  37
  38 void *arpt_alloc_initial_table(const struct xt_table *info)
  39 {
  40         return xt_alloc_initial_table(arpt, ARPT);
  41 }
  42 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  43
  44 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  45                                       const char *hdr_addr, int len)
  46 {
  47         int i, ret;
  48
  49         if (len > ARPT_DEV_ADDR_LEN_MAX)
  50                 len = ARPT_DEV_ADDR_LEN_MAX;
  51
  52         ret = 0;
  53         for (i = 0; i < len; i++)
  54                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  55
  56         return ret != 0;
  57 }
  58
  59 /*
  60  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  61  * Some arches dont care, unrolling the loop is a win on them.
  62  * For other arches, we only have a 16bit alignement.
  63  */
  64 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  65 {
  66 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  67         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  68 #else
  69         unsigned long ret = 0;
  70         const u16 *a = (const u16 *)_a;
  71         const u16 *b = (const u16 *)_b;
  72         const u16 *mask = (const u16 *)_mask;
  73         int i;
  74
  75         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  76                 ret |= (a[i] ^ b[i]) & mask[i];
  77 #endif
  78         return ret;
  79 }
  80
  81 /* Returns whether packet matches rule or not. */
  82 static inline int arp_packet_match(const struct arphdr *arphdr,
  83                                    struct net_device *dev,
  84                                    const char *indev,
  85                                    const char *outdev,
  86                                    const struct arpt_arp *arpinfo)
  87 {
  88         const char *arpptr = (char *)(arphdr + 1);
  89         const char *src_devaddr, *tgt_devaddr;
  90         __be32 src_ipaddr, tgt_ipaddr;
  91         long ret;
  92
  93         if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
  94                     (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
  95                 return 0;
  96
  97         if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
  98                     (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
  99                 return 0;
 100
 101         if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
 102                     (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
 103                 return 0;
 104
 105         if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
 106                     (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
 107                 return 0;
 108
 109         src_devaddr = arpptr;
 110         arpptr += dev->addr_len;
 111         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 112         arpptr += sizeof(u32);
 113         tgt_devaddr = arpptr;
 114         arpptr += dev->addr_len;
 115         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 116
 117         if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
 118                     arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
 119                                         dev->addr_len)) ||
 120             NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
 121                     arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
 122                                         dev->addr_len)))
 123                 return 0;
 124
 125         if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
 126                     (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
 127             NF_INVF(arpinfo, ARPT_INV_TGTIP,
 128                     (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
 129                 return 0;
 130
 131         /* Look for ifname matches.  */
 132         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 133
 134         if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
 135                 return 0;
 136
 137         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 138
 139         if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
 140                 return 0;
 141
 142         return 1;
 143 }
 144
 145 static inline int arp_checkentry(const struct arpt_arp *arp)
 146 {
 147         if (arp->flags & ~ARPT_F_MASK)
 148                 return 0;
 149         if (arp->invflags & ~ARPT_INV_MASK)
 150                 return 0;
 151
 152         return 1;
 153 }
 154
 155 static unsigned int
 156 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 157 {
 158         net_err_ratelimited("arp_tables: error: '%s'\n",
 159                             (const char *)par->targinfo);
 160
 161         return NF_DROP;
 162 }
 163
 164 static inline const struct xt_entry_target *
 165 arpt_get_target_c(const struct arpt_entry *e)
 166 {
 167         return arpt_get_target((struct arpt_entry *)e);
 168 }
 169
 170 static inline struct arpt_entry *
 171 get_entry(const void *base, unsigned int offset)
 172 {
 173         return (struct arpt_entry *)(base + offset);
 174 }
 175
 176 static inline
 177 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 178 {
 179         return (void *)entry + entry->next_offset;
 180 }
 181
 182 unsigned int arpt_do_table(void *priv,
 183                            struct sk_buff *skb,
 184                            const struct nf_hook_state *state)
 185 {
 186         const struct xt_table *table = priv;
 187         unsigned int hook = state->hook;
 188         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 189         unsigned int verdict = NF_DROP;
 190         const struct arphdr *arp;
 191         struct arpt_entry *e, **jumpstack;
 192         const char *indev, *outdev;
 193         const void *table_base;
 194         unsigned int cpu, stackidx = 0;
 195         const struct xt_table_info *private;
 196         struct xt_action_param acpar;
 197         unsigned int addend;
 198
 199         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 200                 return NF_DROP;
 201
 202         indev = state->in ? state->in->name : nulldevname;
 203         outdev = state->out ? state->out->name : nulldevname;
 204
 205         local_bh_disable();
 206         addend = xt_write_recseq_begin();
 207         private = READ_ONCE(table->private); /* Address dependency. */
 208         cpu     = smp_processor_id();
 209         table_base = private->entries;
 210         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 211
 212         /* No TEE support for arptables, so no need to switch to alternate
 213          * stack.  All targets that reenter must return absolute verdicts.
 214          */
 215         e = get_entry(table_base, private->hook_entry[hook]);
 216
 217         acpar.state   = state;
 218         acpar.hotdrop = false;
 219
 220         arp = arp_hdr(skb);
 221         do {
 222                 const struct xt_entry_target *t;
 223                 struct xt_counters *counter;
 224
 225                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 226                         e = arpt_next_entry(e);
 227                         continue;
 228                 }
 229
 230                 counter = xt_get_this_cpu_counter(&e->counters);
 231                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 232
 233                 t = arpt_get_target_c(e);
 234
 235                 /* Standard target? */
 236                 if (!t->u.kernel.target->target) {
 237                         int v;
 238
 239                         v = ((struct xt_standard_target *)t)->verdict;
 240                         if (v < 0) {
 241                                 /* Pop from stack? */
 242                                 if (v != XT_RETURN) {
 243                                         verdict = (unsigned int)(-v) - 1;
 244                                         break;
 245                                 }
 246                                 if (stackidx == 0) {
 247                                         e = get_entry(table_base,
 248                                                       private->underflow[hook]);
 249                                 } else {
 250                                         e = jumpstack[--stackidx];
 251                                         e = arpt_next_entry(e);
 252                                 }
 253                                 continue;
 254                         }
 255                         if (table_base + v
 256                             != arpt_next_entry(e)) {
 257                                 if (unlikely(stackidx >= private->stacksize)) {
 258                                         verdict = NF_DROP;
 259                                         break;
 260                                 }
 261                                 jumpstack[stackidx++] = e;
 262                         }
 263
 264                         e = get_entry(table_base, v);
 265                         continue;
 266                 }
 267
 268                 acpar.target   = t->u.kernel.target;
 269                 acpar.targinfo = t->data;
 270                 verdict = t->u.kernel.target->target(skb, &acpar);
 271
 272                 if (verdict == XT_CONTINUE) {
 273                         /* Target might have changed stuff. */
 274                         arp = arp_hdr(skb);
 275                         e = arpt_next_entry(e);
 276                 } else {
 277                         /* Verdict */
 278                         break;
 279                 }
 280         } while (!acpar.hotdrop);
 281         xt_write_recseq_end(addend);
 282         local_bh_enable();
 283
 284         if (acpar.hotdrop)
 285                 return NF_DROP;
 286         else
 287                 return verdict;
 288 }
 289
 290 /* All zeroes == unconditional rule. */
 291 static inline bool unconditional(const struct arpt_entry *e)
 292 {
 293         static const struct arpt_arp uncond;
 294
 295         return e->target_offset == sizeof(struct arpt_entry) &&
 296                memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
 297 }
 298
 299 /* Figures out from what hook each rule can be called: returns 0 if
 300  * there are loops.  Puts hook bitmask in comefrom.
 301  */
 302 static int mark_source_chains(const struct xt_table_info *newinfo,
 303                               unsigned int valid_hooks, void *entry0,
 304                               unsigned int *offsets)
 305 {
 306         unsigned int hook;
 307
 308         /* No recursion; use packet counter to save back ptrs (reset
 309          * to 0 as we leave), and comefrom to save source hook bitmask.
 310          */
 311         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 312                 unsigned int pos = newinfo->hook_entry[hook];
 313                 struct arpt_entry *e = 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                                 /* Return: backtrack through the last
 340                                  * big jump.
 341                                  */
 342                                 do {
 343                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 344                                         oldpos = pos;
 345                                         pos = e->counters.pcnt;
 346                                         e->counters.pcnt = 0;
 347
 348                                         /* We're at the start. */
 349                                         if (pos == oldpos)
 350                                                 goto next;
 351
 352                                         e = entry0 + pos;
 353                                 } while (oldpos == pos + e->next_offset);
 354
 355                                 /* Move along one */
 356                                 size = e->next_offset;
 357                                 e = entry0 + pos + size;
 358                                 if (pos + size >= newinfo->size)
 359                                         return 0;
 360                                 e->counters.pcnt = pos;
 361                                 pos += size;
 362                         } else {
 363                                 int newpos = t->verdict;
 364
 365                                 if (strcmp(t->target.u.user.name,
 366                                            XT_STANDARD_TARGET) == 0 &&
 367                                     newpos >= 0) {
 368                                         /* This a jump; chase it. */
 369                                         if (!xt_find_jump_offset(offsets, newpos,
 370                                                                  newinfo->number))
 371                                                 return 0;
 372                                 } else {
 373                                         /* ... this is a fallthru */
 374                                         newpos = pos + e->next_offset;
 375                                         if (newpos >= newinfo->size)
 376                                                 return 0;
 377                                 }
 378                                 e = entry0 + newpos;
 379                                 e->counters.pcnt = pos;
 380                                 pos = newpos;
 381                         }
 382                 }
 383 next:           ;
 384         }
 385         return 1;
 386 }
 387
 388 static int check_target(struct arpt_entry *e, struct net *net, const char *name)
 389 {
 390         struct xt_entry_target *t = arpt_get_target(e);
 391         struct xt_tgchk_param par = {
 392                 .net       = net,
 393                 .table     = name,
 394                 .entryinfo = e,
 395                 .target    = t->u.kernel.target,
 396                 .targinfo  = t->data,
 397                 .hook_mask = e->comefrom,
 398                 .family    = NFPROTO_ARP,
 399         };
 400
 401         return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 402 }
 403
 404 static int
 405 find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
 406                  unsigned int size,
 407                  struct xt_percpu_counter_alloc_state *alloc_state)
 408 {
 409         struct xt_entry_target *t;
 410         struct xt_target *target;
 411         int ret;
 412
 413         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 414                 return -ENOMEM;
 415
 416         t = arpt_get_target(e);
 417         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 418                                         t->u.user.revision);
 419         if (IS_ERR(target)) {
 420                 ret = PTR_ERR(target);
 421                 goto out;
 422         }
 423         t->u.kernel.target = target;
 424
 425         ret = check_target(e, net, name);
 426         if (ret)
 427                 goto err;
 428         return 0;
 429 err:
 430         module_put(t->u.kernel.target->me);
 431 out:
 432         xt_percpu_counter_free(&e->counters);
 433
 434         return ret;
 435 }
 436
 437 static bool check_underflow(const struct arpt_entry *e)
 438 {
 439         const struct xt_entry_target *t;
 440         unsigned int verdict;
 441
 442         if (!unconditional(e))
 443                 return false;
 444         t = arpt_get_target_c(e);
 445         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 446                 return false;
 447         verdict = ((struct xt_standard_target *)t)->verdict;
 448         verdict = -verdict - 1;
 449         return verdict == NF_DROP || verdict == NF_ACCEPT;
 450 }
 451
 452 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 453                                              struct xt_table_info *newinfo,
 454                                              const unsigned char *base,
 455                                              const unsigned char *limit,
 456                                              const unsigned int *hook_entries,
 457                                              const unsigned int *underflows,
 458                                              unsigned int valid_hooks)
 459 {
 460         unsigned int h;
 461         int err;
 462
 463         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 464             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 465             (unsigned char *)e + e->next_offset > limit)
 466                 return -EINVAL;
 467
 468         if (e->next_offset
 469             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
 470                 return -EINVAL;
 471
 472         if (!arp_checkentry(&e->arp))
 473                 return -EINVAL;
 474
 475         err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 476                                      e->next_offset);
 477         if (err)
 478                 return err;
 479
 480         /* Check hooks & underflows */
 481         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 482                 if (!(valid_hooks & (1 << h)))
 483                         continue;
 484                 if ((unsigned char *)e - base == hook_entries[h])
 485                         newinfo->hook_entry[h] = hook_entries[h];
 486                 if ((unsigned char *)e - base == underflows[h]) {
 487                         if (!check_underflow(e))
 488                                 return -EINVAL;
 489
 490                         newinfo->underflow[h] = underflows[h];
 491                 }
 492         }
 493
 494         /* Clear counters and comefrom */
 495         e->counters = ((struct xt_counters) { 0, 0 });
 496         e->comefrom = 0;
 497         return 0;
 498 }
 499
 500 static void cleanup_entry(struct arpt_entry *e, struct net *net)
 501 {
 502         struct xt_tgdtor_param par;
 503         struct xt_entry_target *t;
 504
 505         t = arpt_get_target(e);
 506         par.net      = net;
 507         par.target   = t->u.kernel.target;
 508         par.targinfo = t->data;
 509         par.family   = NFPROTO_ARP;
 510         if (par.target->destroy != NULL)
 511                 par.target->destroy(&par);
 512         module_put(par.target->me);
 513         xt_percpu_counter_free(&e->counters);
 514 }
 515
 516 /* Checks and translates the user-supplied table segment (held in
 517  * newinfo).
 518  */
 519 static int translate_table(struct net *net,
 520                            struct xt_table_info *newinfo,
 521                            void *entry0,
 522                            const struct arpt_replace *repl)
 523 {
 524         struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 525         struct arpt_entry *iter;
 526         unsigned int *offsets;
 527         unsigned int i;
 528         int ret = 0;
 529
 530         newinfo->size = repl->size;
 531         newinfo->number = repl->num_entries;
 532
 533         /* Init all hooks to impossible value. */
 534         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 535                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 536                 newinfo->underflow[i] = 0xFFFFFFFF;
 537         }
 538
 539         offsets = xt_alloc_entry_offsets(newinfo->number);
 540         if (!offsets)
 541                 return -ENOMEM;
 542         i = 0;
 543
 544         /* Walk through entries, checking offsets. */
 545         xt_entry_foreach(iter, entry0, newinfo->size) {
 546                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 547                                                  entry0 + repl->size,
 548                                                  repl->hook_entry,
 549                                                  repl->underflow,
 550                                                  repl->valid_hooks);
 551                 if (ret != 0)
 552                         goto out_free;
 553                 if (i < repl->num_entries)
 554                         offsets[i] = (void *)iter - entry0;
 555                 ++i;
 556                 if (strcmp(arpt_get_target(iter)->u.user.name,
 557                     XT_ERROR_TARGET) == 0)
 558                         ++newinfo->stacksize;
 559         }
 560
 561         ret = -EINVAL;
 562         if (i != repl->num_entries)
 563                 goto out_free;
 564
 565         ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
 566         if (ret)
 567                 goto out_free;
 568
 569         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 570                 ret = -ELOOP;
 571                 goto out_free;
 572         }
 573         kvfree(offsets);
 574
 575         /* Finally, each sanity check must pass */
 576         i = 0;
 577         xt_entry_foreach(iter, entry0, newinfo->size) {
 578                 ret = find_check_entry(iter, net, repl->name, repl->size,
 579                                        &alloc_state);
 580                 if (ret != 0)
 581                         break;
 582                 ++i;
 583         }
 584
 585         if (ret != 0) {
 586                 xt_entry_foreach(iter, entry0, newinfo->size) {
 587                         if (i-- == 0)
 588                                 break;
 589                         cleanup_entry(iter, net);
 590                 }
 591                 return ret;
 592         }
 593
 594         return ret;
 595  out_free:
 596         kvfree(offsets);
 597         return ret;
 598 }
 599
 600 static void get_counters(const struct xt_table_info *t,
 601                          struct xt_counters counters[])
 602 {
 603         struct arpt_entry *iter;
 604         unsigned int cpu;
 605         unsigned int i;
 606
 607         for_each_possible_cpu(cpu) {
 608                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 609
 610                 i = 0;
 611                 xt_entry_foreach(iter, t->entries, t->size) {
 612                         struct xt_counters *tmp;
 613                         u64 bcnt, pcnt;
 614                         unsigned int start;
 615
 616                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 617                         do {
 618                                 start = read_seqcount_begin(s);
 619                                 bcnt = tmp->bcnt;
 620                                 pcnt = tmp->pcnt;
 621                         } while (read_seqcount_retry(s, start));
 622
 623                         ADD_COUNTER(counters[i], bcnt, pcnt);
 624                         ++i;
 625                         cond_resched();
 626                 }
 627         }
 628 }
 629
 630 static void get_old_counters(const struct xt_table_info *t,
 631                              struct xt_counters counters[])
 632 {
 633         struct arpt_entry *iter;
 634         unsigned int cpu, i;
 635
 636         for_each_possible_cpu(cpu) {
 637                 i = 0;
 638                 xt_entry_foreach(iter, t->entries, t->size) {
 639                         struct xt_counters *tmp;
 640
 641                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 642                         ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
 643                         ++i;
 644                 }
 645                 cond_resched();
 646         }
 647 }
 648
 649 static struct xt_counters *alloc_counters(const struct xt_table *table)
 650 {
 651         unsigned int countersize;
 652         struct xt_counters *counters;
 653         const struct xt_table_info *private = table->private;
 654
 655         /* We need atomic snapshot of counters: rest doesn't change
 656          * (other than comefrom, which userspace doesn't care
 657          * about).
 658          */
 659         countersize = sizeof(struct xt_counters) * private->number;
 660         counters = vzalloc(countersize);
 661
 662         if (counters == NULL)
 663                 return ERR_PTR(-ENOMEM);
 664
 665         get_counters(private, counters);
 666
 667         return counters;
 668 }
 669
 670 static int copy_entries_to_user(unsigned int total_size,
 671                                 const struct xt_table *table,
 672                                 void __user *userptr)
 673 {
 674         unsigned int off, num;
 675         const struct arpt_entry *e;
 676         struct xt_counters *counters;
 677         struct xt_table_info *private = table->private;
 678         int ret = 0;
 679         void *loc_cpu_entry;
 680
 681         counters = alloc_counters(table);
 682         if (IS_ERR(counters))
 683                 return PTR_ERR(counters);
 684
 685         loc_cpu_entry = private->entries;
 686
 687         /* FIXME: use iterator macros --RR */
 688         /* ... then go back and fix counters and names */
 689         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 690                 const struct xt_entry_target *t;
 691
 692                 e = loc_cpu_entry + off;
 693                 if (copy_to_user(userptr + off, e, sizeof(*e))) {
 694                         ret = -EFAULT;
 695                         goto free_counters;
 696                 }
 697                 if (copy_to_user(userptr + off
 698                                  + offsetof(struct arpt_entry, counters),
 699                                  &counters[num],
 700                                  sizeof(counters[num])) != 0) {
 701                         ret = -EFAULT;
 702                         goto free_counters;
 703                 }
 704
 705                 t = arpt_get_target_c(e);
 706                 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
 707                         ret = -EFAULT;
 708                         goto free_counters;
 709                 }
 710         }
 711
 712  free_counters:
 713         vfree(counters);
 714         return ret;
 715 }
 716
 717 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 718 static void compat_standard_from_user(void *dst, const void *src)
 719 {
 720         int v = *(compat_int_t *)src;
 721
 722         if (v > 0)
 723                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 724         memcpy(dst, &v, sizeof(v));
 725 }
 726
 727 static int compat_standard_to_user(void __user *dst, const void *src)
 728 {
 729         compat_int_t cv = *(int *)src;
 730
 731         if (cv > 0)
 732                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 733         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 734 }
 735
 736 static int compat_calc_entry(const struct arpt_entry *e,
 737                              const struct xt_table_info *info,
 738                              const void *base, struct xt_table_info *newinfo)
 739 {
 740         const struct xt_entry_target *t;
 741         unsigned int entry_offset;
 742         int off, i, ret;
 743
 744         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 745         entry_offset = (void *)e - base;
 746
 747         t = arpt_get_target_c(e);
 748         off += xt_compat_target_offset(t->u.kernel.target);
 749         newinfo->size -= off;
 750         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 751         if (ret)
 752                 return ret;
 753
 754         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 755                 if (info->hook_entry[i] &&
 756                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 757                         newinfo->hook_entry[i] -= off;
 758                 if (info->underflow[i] &&
 759                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 760                         newinfo->underflow[i] -= off;
 761         }
 762         return 0;
 763 }
 764
 765 static int compat_table_info(const struct xt_table_info *info,
 766                              struct xt_table_info *newinfo)
 767 {
 768         struct arpt_entry *iter;
 769         const void *loc_cpu_entry;
 770         int ret;
 771
 772         if (!newinfo || !info)
 773                 return -EINVAL;
 774
 775         /* we dont care about newinfo->entries */
 776         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 777         newinfo->initial_entries = 0;
 778         loc_cpu_entry = info->entries;
 779         ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
 780         if (ret)
 781                 return ret;
 782         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 783                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 784                 if (ret != 0)
 785                         return ret;
 786         }
 787         return 0;
 788 }
 789 #endif
 790
 791 static int get_info(struct net *net, void __user *user, const int *len)
 792 {
 793         char name[XT_TABLE_MAXNAMELEN];
 794         struct xt_table *t;
 795         int ret;
 796
 797         if (*len != sizeof(struct arpt_getinfo))
 798                 return -EINVAL;
 799
 800         if (copy_from_user(name, user, sizeof(name)) != 0)
 801                 return -EFAULT;
 802
 803         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 804 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 805         if (in_compat_syscall())
 806                 xt_compat_lock(NFPROTO_ARP);
 807 #endif
 808         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 809         if (!IS_ERR(t)) {
 810                 struct arpt_getinfo info;
 811                 const struct xt_table_info *private = t->private;
 812 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 813                 struct xt_table_info tmp;
 814
 815                 if (in_compat_syscall()) {
 816                         ret = compat_table_info(private, &tmp);
 817                         xt_compat_flush_offsets(NFPROTO_ARP);
 818                         private = &tmp;
 819                 }
 820 #endif
 821                 memset(&info, 0, sizeof(info));
 822                 info.valid_hooks = t->valid_hooks;
 823                 memcpy(info.hook_entry, private->hook_entry,
 824                        sizeof(info.hook_entry));
 825                 memcpy(info.underflow, private->underflow,
 826                        sizeof(info.underflow));
 827                 info.num_entries = private->number;
 828                 info.size = private->size;
 829                 strcpy(info.name, name);
 830
 831                 if (copy_to_user(user, &info, *len) != 0)
 832                         ret = -EFAULT;
 833                 else
 834                         ret = 0;
 835                 xt_table_unlock(t);
 836                 module_put(t->me);
 837         } else
 838                 ret = PTR_ERR(t);
 839 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 840         if (in_compat_syscall())
 841                 xt_compat_unlock(NFPROTO_ARP);
 842 #endif
 843         return ret;
 844 }
 845
 846 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 847                        const int *len)
 848 {
 849         int ret;
 850         struct arpt_get_entries get;
 851         struct xt_table *t;
 852
 853         if (*len < sizeof(get))
 854                 return -EINVAL;
 855         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 856                 return -EFAULT;
 857         if (*len != sizeof(struct arpt_get_entries) + get.size)
 858                 return -EINVAL;
 859
 860         get.name[sizeof(get.name) - 1] = '\0';
 861
 862         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 863         if (!IS_ERR(t)) {
 864                 const struct xt_table_info *private = t->private;
 865
 866                 if (get.size == private->size)
 867                         ret = copy_entries_to_user(private->size,
 868                                                    t, uptr->entrytable);
 869                 else
 870                         ret = -EAGAIN;
 871
 872                 module_put(t->me);
 873                 xt_table_unlock(t);
 874         } else
 875                 ret = PTR_ERR(t);
 876
 877         return ret;
 878 }
 879
 880 static int __do_replace(struct net *net, const char *name,
 881                         unsigned int valid_hooks,
 882                         struct xt_table_info *newinfo,
 883                         unsigned int num_counters,
 884                         void __user *counters_ptr)
 885 {
 886         int ret;
 887         struct xt_table *t;
 888         struct xt_table_info *oldinfo;
 889         struct xt_counters *counters;
 890         void *loc_cpu_old_entry;
 891         struct arpt_entry *iter;
 892
 893         ret = 0;
 894         counters = xt_counters_alloc(num_counters);
 895         if (!counters) {
 896                 ret = -ENOMEM;
 897                 goto out;
 898         }
 899
 900         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 901         if (IS_ERR(t)) {
 902                 ret = PTR_ERR(t);
 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         xt_table_unlock(t);
 925
 926         get_old_counters(oldinfo, counters);
 927
 928         /* Decrease module usage counts and free resource */
 929         loc_cpu_old_entry = oldinfo->entries;
 930         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
 931                 cleanup_entry(iter, net);
 932
 933         xt_free_table_info(oldinfo);
 934         if (copy_to_user(counters_ptr, counters,
 935                          sizeof(struct xt_counters) * num_counters) != 0) {
 936                 /* Silent error, can't fail, new table is already in place */
 937                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
 938         }
 939         vfree(counters);
 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, sockptr_t arg, unsigned int len)
 952 {
 953         int ret;
 954         struct arpt_replace tmp;
 955         struct xt_table_info *newinfo;
 956         void *loc_cpu_entry;
 957         struct arpt_entry *iter;
 958
 959         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
 960                 return -EFAULT;
 961
 962         /* overflow check */
 963         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 964                 return -ENOMEM;
 965         if (tmp.num_counters == 0)
 966                 return -EINVAL;
 967
 968         tmp.name[sizeof(tmp.name)-1] = 0;
 969
 970         newinfo = xt_alloc_table_info(tmp.size);
 971         if (!newinfo)
 972                 return -ENOMEM;
 973
 974         loc_cpu_entry = newinfo->entries;
 975         if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
 976                         tmp.size) != 0) {
 977                 ret = -EFAULT;
 978                 goto free_newinfo;
 979         }
 980
 981         ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
 982         if (ret != 0)
 983                 goto free_newinfo;
 984
 985         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
 986                            tmp.num_counters, tmp.counters);
 987         if (ret)
 988                 goto free_newinfo_untrans;
 989         return 0;
 990
 991  free_newinfo_untrans:
 992         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
 993                 cleanup_entry(iter, net);
 994  free_newinfo:
 995         xt_free_table_info(newinfo);
 996         return ret;
 997 }
 998
 999 static int do_add_counters(struct net *net, sockptr_t arg, unsigned int len)
1000 {
1001         unsigned int i;
1002         struct xt_counters_info tmp;
1003         struct xt_counters *paddc;
1004         struct xt_table *t;
1005         const struct xt_table_info *private;
1006         int ret = 0;
1007         struct arpt_entry *iter;
1008         unsigned int addend;
1009
1010         paddc = xt_copy_counters(arg, len, &tmp);
1011         if (IS_ERR(paddc))
1012                 return PTR_ERR(paddc);
1013
1014         t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1015         if (IS_ERR(t)) {
1016                 ret = PTR_ERR(t);
1017                 goto free;
1018         }
1019
1020         local_bh_disable();
1021         private = t->private;
1022         if (private->number != tmp.num_counters) {
1023                 ret = -EINVAL;
1024                 goto unlock_up_free;
1025         }
1026
1027         i = 0;
1028
1029         addend = xt_write_recseq_begin();
1030         xt_entry_foreach(iter,  private->entries, private->size) {
1031                 struct xt_counters *tmp;
1032
1033                 tmp = xt_get_this_cpu_counter(&iter->counters);
1034                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1035                 ++i;
1036         }
1037         xt_write_recseq_end(addend);
1038  unlock_up_free:
1039         local_bh_enable();
1040         xt_table_unlock(t);
1041         module_put(t->me);
1042  free:
1043         vfree(paddc);
1044
1045         return ret;
1046 }
1047
1048 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1049 struct compat_arpt_replace {
1050         char                            name[XT_TABLE_MAXNAMELEN];
1051         u32                             valid_hooks;
1052         u32                             num_entries;
1053         u32                             size;
1054         u32                             hook_entry[NF_ARP_NUMHOOKS];
1055         u32                             underflow[NF_ARP_NUMHOOKS];
1056         u32                             num_counters;
1057         compat_uptr_t                   counters;
1058         struct compat_arpt_entry        entries[];
1059 };
1060
1061 static inline void compat_release_entry(struct compat_arpt_entry *e)
1062 {
1063         struct xt_entry_target *t;
1064
1065         t = compat_arpt_get_target(e);
1066         module_put(t->u.kernel.target->me);
1067 }
1068
1069 static int
1070 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1071                                   struct xt_table_info *newinfo,
1072                                   unsigned int *size,
1073                                   const unsigned char *base,
1074                                   const unsigned char *limit)
1075 {
1076         struct xt_entry_target *t;
1077         struct xt_target *target;
1078         unsigned int entry_offset;
1079         int ret, off;
1080
1081         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1082             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1083             (unsigned char *)e + e->next_offset > limit)
1084                 return -EINVAL;
1085
1086         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1087                              sizeof(struct compat_xt_entry_target))
1088                 return -EINVAL;
1089
1090         if (!arp_checkentry(&e->arp))
1091                 return -EINVAL;
1092
1093         ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1094                                             e->next_offset);
1095         if (ret)
1096                 return ret;
1097
1098         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1099         entry_offset = (void *)e - (void *)base;
1100
1101         t = compat_arpt_get_target(e);
1102         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1103                                         t->u.user.revision);
1104         if (IS_ERR(target)) {
1105                 ret = PTR_ERR(target);
1106                 goto out;
1107         }
1108         t->u.kernel.target = target;
1109
1110         off += xt_compat_target_offset(target);
1111         *size += off;
1112         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1113         if (ret)
1114                 goto release_target;
1115
1116         return 0;
1117
1118 release_target:
1119         module_put(t->u.kernel.target->me);
1120 out:
1121         return ret;
1122 }
1123
1124 static void
1125 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1126                             unsigned int *size,
1127                             struct xt_table_info *newinfo, unsigned char *base)
1128 {
1129         struct xt_entry_target *t;
1130         struct arpt_entry *de;
1131         unsigned int origsize;
1132         int h;
1133
1134         origsize = *size;
1135         de = *dstptr;
1136         memcpy(de, e, sizeof(struct arpt_entry));
1137         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1138
1139         *dstptr += sizeof(struct arpt_entry);
1140         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1141
1142         de->target_offset = e->target_offset - (origsize - *size);
1143         t = compat_arpt_get_target(e);
1144         xt_compat_target_from_user(t, dstptr, size);
1145
1146         de->next_offset = e->next_offset - (origsize - *size);
1147         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1148                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1149                         newinfo->hook_entry[h] -= origsize - *size;
1150                 if ((unsigned char *)de - base < newinfo->underflow[h])
1151                         newinfo->underflow[h] -= origsize - *size;
1152         }
1153 }
1154
1155 static int translate_compat_table(struct net *net,
1156                                   struct xt_table_info **pinfo,
1157                                   void **pentry0,
1158                                   const struct compat_arpt_replace *compatr)
1159 {
1160         unsigned int i, j;
1161         struct xt_table_info *newinfo, *info;
1162         void *pos, *entry0, *entry1;
1163         struct compat_arpt_entry *iter0;
1164         struct arpt_replace repl;
1165         unsigned int size;
1166         int ret;
1167
1168         info = *pinfo;
1169         entry0 = *pentry0;
1170         size = compatr->size;
1171         info->number = compatr->num_entries;
1172
1173         j = 0;
1174         xt_compat_lock(NFPROTO_ARP);
1175         ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1176         if (ret)
1177                 goto out_unlock;
1178         /* Walk through entries, checking offsets. */
1179         xt_entry_foreach(iter0, entry0, compatr->size) {
1180                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1181                                                         entry0,
1182                                                         entry0 + compatr->size);
1183                 if (ret != 0)
1184                         goto out_unlock;
1185                 ++j;
1186         }
1187
1188         ret = -EINVAL;
1189         if (j != compatr->num_entries)
1190                 goto out_unlock;
1191
1192         ret = -ENOMEM;
1193         newinfo = xt_alloc_table_info(size);
1194         if (!newinfo)
1195                 goto out_unlock;
1196
1197         memset(newinfo->entries, 0, size);
1198
1199         newinfo->number = compatr->num_entries;
1200         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1201                 newinfo->hook_entry[i] = compatr->hook_entry[i];
1202                 newinfo->underflow[i] = compatr->underflow[i];
1203         }
1204         entry1 = newinfo->entries;
1205         pos = entry1;
1206         size = compatr->size;
1207         xt_entry_foreach(iter0, entry0, compatr->size)
1208                 compat_copy_entry_from_user(iter0, &pos, &size,
1209                                             newinfo, entry1);
1210
1211         /* all module references in entry0 are now gone */
1212
1213         xt_compat_flush_offsets(NFPROTO_ARP);
1214         xt_compat_unlock(NFPROTO_ARP);
1215
1216         memcpy(&repl, compatr, sizeof(*compatr));
1217
1218         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1219                 repl.hook_entry[i] = newinfo->hook_entry[i];
1220                 repl.underflow[i] = newinfo->underflow[i];
1221         }
1222
1223         repl.num_counters = 0;
1224         repl.counters = NULL;
1225         repl.size = newinfo->size;
1226         ret = translate_table(net, newinfo, entry1, &repl);
1227         if (ret)
1228                 goto free_newinfo;
1229
1230         *pinfo = newinfo;
1231         *pentry0 = entry1;
1232         xt_free_table_info(info);
1233         return 0;
1234
1235 free_newinfo:
1236         xt_free_table_info(newinfo);
1237         return ret;
1238 out_unlock:
1239         xt_compat_flush_offsets(NFPROTO_ARP);
1240         xt_compat_unlock(NFPROTO_ARP);
1241         xt_entry_foreach(iter0, entry0, compatr->size) {
1242                 if (j-- == 0)
1243                         break;
1244                 compat_release_entry(iter0);
1245         }
1246         return ret;
1247 }
1248
1249 static int compat_do_replace(struct net *net, sockptr_t arg, 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_sockptr(&tmp, arg, 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_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
1274                         tmp.size) != 0) {
1275                 ret = -EFAULT;
1276                 goto free_newinfo;
1277         }
1278
1279         ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1280         if (ret != 0)
1281                 goto free_newinfo;
1282
1283         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1284                            tmp.num_counters, compat_ptr(tmp.counters));
1285         if (ret)
1286                 goto free_newinfo_untrans;
1287         return 0;
1288
1289  free_newinfo_untrans:
1290         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1291                 cleanup_entry(iter, net);
1292  free_newinfo:
1293         xt_free_table_info(newinfo);
1294         return ret;
1295 }
1296
1297 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1298                                      compat_uint_t *size,
1299                                      struct xt_counters *counters,
1300                                      unsigned int i)
1301 {
1302         struct xt_entry_target *t;
1303         struct compat_arpt_entry __user *ce;
1304         u_int16_t target_offset, next_offset;
1305         compat_uint_t origsize;
1306         int ret;
1307
1308         origsize = *size;
1309         ce = *dstptr;
1310         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1311             copy_to_user(&ce->counters, &counters[i],
1312             sizeof(counters[i])) != 0)
1313                 return -EFAULT;
1314
1315         *dstptr += sizeof(struct compat_arpt_entry);
1316         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1317
1318         target_offset = e->target_offset - (origsize - *size);
1319
1320         t = arpt_get_target(e);
1321         ret = xt_compat_target_to_user(t, dstptr, size);
1322         if (ret)
1323                 return ret;
1324         next_offset = e->next_offset - (origsize - *size);
1325         if (put_user(target_offset, &ce->target_offset) != 0 ||
1326             put_user(next_offset, &ce->next_offset) != 0)
1327                 return -EFAULT;
1328         return 0;
1329 }
1330
1331 static int compat_copy_entries_to_user(unsigned int total_size,
1332                                        struct xt_table *table,
1333                                        void __user *userptr)
1334 {
1335         struct xt_counters *counters;
1336         const struct xt_table_info *private = table->private;
1337         void __user *pos;
1338         unsigned int size;
1339         int ret = 0;
1340         unsigned int i = 0;
1341         struct arpt_entry *iter;
1342
1343         counters = alloc_counters(table);
1344         if (IS_ERR(counters))
1345                 return PTR_ERR(counters);
1346
1347         pos = userptr;
1348         size = total_size;
1349         xt_entry_foreach(iter, private->entries, total_size) {
1350                 ret = compat_copy_entry_to_user(iter, &pos,
1351                                                 &size, counters, i++);
1352                 if (ret != 0)
1353                         break;
1354         }
1355         vfree(counters);
1356         return ret;
1357 }
1358
1359 struct compat_arpt_get_entries {
1360         char name[XT_TABLE_MAXNAMELEN];
1361         compat_uint_t size;
1362         struct compat_arpt_entry entrytable[];
1363 };
1364
1365 static int compat_get_entries(struct net *net,
1366                               struct compat_arpt_get_entries __user *uptr,
1367                               int *len)
1368 {
1369         int ret;
1370         struct compat_arpt_get_entries get;
1371         struct xt_table *t;
1372
1373         if (*len < sizeof(get))
1374                 return -EINVAL;
1375         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1376                 return -EFAULT;
1377         if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1378                 return -EINVAL;
1379
1380         get.name[sizeof(get.name) - 1] = '\0';
1381
1382         xt_compat_lock(NFPROTO_ARP);
1383         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1384         if (!IS_ERR(t)) {
1385                 const struct xt_table_info *private = t->private;
1386                 struct xt_table_info info;
1387
1388                 ret = compat_table_info(private, &info);
1389                 if (!ret && get.size == info.size) {
1390                         ret = compat_copy_entries_to_user(private->size,
1391                                                           t, uptr->entrytable);
1392                 } else if (!ret)
1393                         ret = -EAGAIN;
1394
1395                 xt_compat_flush_offsets(NFPROTO_ARP);
1396                 module_put(t->me);
1397                 xt_table_unlock(t);
1398         } else
1399                 ret = PTR_ERR(t);
1400
1401         xt_compat_unlock(NFPROTO_ARP);
1402         return ret;
1403 }
1404 #endif
1405
1406 static int do_arpt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
1407                 unsigned int len)
1408 {
1409         int ret;
1410
1411         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1412                 return -EPERM;
1413
1414         switch (cmd) {
1415         case ARPT_SO_SET_REPLACE:
1416 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1417                 if (in_compat_syscall())
1418                         ret = compat_do_replace(sock_net(sk), arg, len);
1419                 else
1420 #endif
1421                         ret = do_replace(sock_net(sk), arg, len);
1422                 break;
1423
1424         case ARPT_SO_SET_ADD_COUNTERS:
1425                 ret = do_add_counters(sock_net(sk), arg, len);
1426                 break;
1427
1428         default:
1429                 ret = -EINVAL;
1430         }
1431
1432         return ret;
1433 }
1434
1435 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1436 {
1437         int ret;
1438
1439         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1440                 return -EPERM;
1441
1442         switch (cmd) {
1443         case ARPT_SO_GET_INFO:
1444                 ret = get_info(sock_net(sk), user, len);
1445                 break;
1446
1447         case ARPT_SO_GET_ENTRIES:
1448 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1449                 if (in_compat_syscall())
1450                         ret = compat_get_entries(sock_net(sk), user, len);
1451                 else
1452 #endif
1453                         ret = get_entries(sock_net(sk), user, len);
1454                 break;
1455
1456         case ARPT_SO_GET_REVISION_TARGET: {
1457                 struct xt_get_revision rev;
1458
1459                 if (*len != sizeof(rev)) {
1460                         ret = -EINVAL;
1461                         break;
1462                 }
1463                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1464                         ret = -EFAULT;
1465                         break;
1466                 }
1467                 rev.name[sizeof(rev.name)-1] = 0;
1468
1469                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1470                                                          rev.revision, 1, &ret),
1471                                         "arpt_%s", rev.name);
1472                 break;
1473         }
1474
1475         default:
1476                 ret = -EINVAL;
1477         }
1478
1479         return ret;
1480 }
1481
1482 static void __arpt_unregister_table(struct net *net, struct xt_table *table)
1483 {
1484         struct xt_table_info *private;
1485         void *loc_cpu_entry;
1486         struct module *table_owner = table->me;
1487         struct arpt_entry *iter;
1488
1489         private = xt_unregister_table(table);
1490
1491         /* Decrease module usage counts and free resources */
1492         loc_cpu_entry = private->entries;
1493         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1494                 cleanup_entry(iter, net);
1495         if (private->number > private->initial_entries)
1496                 module_put(table_owner);
1497         xt_free_table_info(private);
1498 }
1499
1500 int arpt_register_table(struct net *net,
1501                         const struct xt_table *table,
1502                         const struct arpt_replace *repl,
1503                         const struct nf_hook_ops *template_ops)
1504 {
1505         struct nf_hook_ops *ops;
1506         unsigned int num_ops;
1507         int ret, i;
1508         struct xt_table_info *newinfo;
1509         struct xt_table_info bootstrap = {0};
1510         void *loc_cpu_entry;
1511         struct xt_table *new_table;
1512
1513         newinfo = xt_alloc_table_info(repl->size);
1514         if (!newinfo)
1515                 return -ENOMEM;
1516
1517         loc_cpu_entry = newinfo->entries;
1518         memcpy(loc_cpu_entry, repl->entries, repl->size);
1519
1520         ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1521         if (ret != 0) {
1522                 xt_free_table_info(newinfo);
1523                 return ret;
1524         }
1525
1526         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1527         if (IS_ERR(new_table)) {
1528                 xt_free_table_info(newinfo);
1529                 return PTR_ERR(new_table);
1530         }
1531
1532         num_ops = hweight32(table->valid_hooks);
1533         if (num_ops == 0) {
1534                 ret = -EINVAL;
1535                 goto out_free;
1536         }
1537
1538         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1539         if (!ops) {
1540                 ret = -ENOMEM;
1541                 goto out_free;
1542         }
1543
1544         for (i = 0; i < num_ops; i++)
1545                 ops[i].priv = new_table;
1546
1547         new_table->ops = ops;
1548
1549         ret = nf_register_net_hooks(net, ops, num_ops);
1550         if (ret != 0)
1551                 goto out_free;
1552
1553         return ret;
1554
1555 out_free:
1556         __arpt_unregister_table(net, new_table);
1557         return ret;
1558 }
1559
1560 void arpt_unregister_table_pre_exit(struct net *net, const char *name)
1561 {
1562         struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name);
1563
1564         if (table)
1565                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1566 }
1567 EXPORT_SYMBOL(arpt_unregister_table_pre_exit);
1568
1569 void arpt_unregister_table(struct net *net, const char *name)
1570 {
1571         struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name);
1572
1573         if (table)
1574                 __arpt_unregister_table(net, table);
1575 }
1576
1577 /* The built-in targets: standard (NULL) and error. */
1578 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1579         {
1580                 .name             = XT_STANDARD_TARGET,
1581                 .targetsize       = sizeof(int),
1582                 .family           = NFPROTO_ARP,
1583 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1584                 .compatsize       = sizeof(compat_int_t),
1585                 .compat_from_user = compat_standard_from_user,
1586                 .compat_to_user   = compat_standard_to_user,
1587 #endif
1588         },
1589         {
1590                 .name             = XT_ERROR_TARGET,
1591                 .target           = arpt_error,
1592                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1593                 .family           = NFPROTO_ARP,
1594         },
1595 };
1596
1597 static struct nf_sockopt_ops arpt_sockopts = {
1598         .pf             = PF_INET,
1599         .set_optmin     = ARPT_BASE_CTL,
1600         .set_optmax     = ARPT_SO_SET_MAX+1,
1601         .set            = do_arpt_set_ctl,
1602         .get_optmin     = ARPT_BASE_CTL,
1603         .get_optmax     = ARPT_SO_GET_MAX+1,
1604         .get            = do_arpt_get_ctl,
1605         .owner          = THIS_MODULE,
1606 };
1607
1608 static int __net_init arp_tables_net_init(struct net *net)
1609 {
1610         return xt_proto_init(net, NFPROTO_ARP);
1611 }
1612
1613 static void __net_exit arp_tables_net_exit(struct net *net)
1614 {
1615         xt_proto_fini(net, NFPROTO_ARP);
1616 }
1617
1618 static struct pernet_operations arp_tables_net_ops = {
1619         .init = arp_tables_net_init,
1620         .exit = arp_tables_net_exit,
1621 };
1622
1623 static int __init arp_tables_init(void)
1624 {
1625         int ret;
1626
1627         ret = register_pernet_subsys(&arp_tables_net_ops);
1628         if (ret < 0)
1629                 goto err1;
1630
1631         /* No one else will be downing sem now, so we won't sleep */
1632         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1633         if (ret < 0)
1634                 goto err2;
1635
1636         /* Register setsockopt */
1637         ret = nf_register_sockopt(&arpt_sockopts);
1638         if (ret < 0)
1639                 goto err4;
1640
1641         return 0;
1642
1643 err4:
1644         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1645 err2:
1646         unregister_pernet_subsys(&arp_tables_net_ops);
1647 err1:
1648         return ret;
1649 }
1650
1651 static void __exit arp_tables_fini(void)
1652 {
1653         nf_unregister_sockopt(&arpt_sockopts);
1654         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1655         unregister_pernet_subsys(&arp_tables_net_ops);
1656 }
1657
1658 EXPORT_SYMBOL(arpt_register_table);
1659 EXPORT_SYMBOL(arpt_unregister_table);
1660 EXPORT_SYMBOL(arpt_do_table);
1661
1662 module_init(arp_tables_init);
1663 module_exit(arp_tables_fini);