net/ipv4/netfilter/arp_tables.c

   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
  10  *
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13 #include <linux/kernel.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/capability.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/kmod.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/mutex.h>
  24 #include <linux/err.h>
  25 #include <net/compat.h>
  26 #include <net/sock.h>
  27 #include <linux/uaccess.h>
  28
  29 #include <linux/netfilter/x_tables.h>
  30 #include <linux/netfilter_arp/arp_tables.h>
  31 #include "../../netfilter/xt_repldata.h"
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  35 MODULE_DESCRIPTION("arptables core");
  36
  37 void *arpt_alloc_initial_table(const struct xt_table *info)
  38 {
  39         return xt_alloc_initial_table(arpt, ARPT);
  40 }
  41 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  42
  43 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  44                                       const char *hdr_addr, int len)
  45 {
  46         int i, ret;
  47
  48         if (len > ARPT_DEV_ADDR_LEN_MAX)
  49                 len = ARPT_DEV_ADDR_LEN_MAX;
  50
  51         ret = 0;
  52         for (i = 0; i < len; i++)
  53                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  54
  55         return ret != 0;
  56 }
  57
  58 /*
  59  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  60  * Some arches dont care, unrolling the loop is a win on them.
  61  * For other arches, we only have a 16bit alignement.
  62  */
  63 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  64 {
  65 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  66         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  67 #else
  68         unsigned long ret = 0;
  69         const u16 *a = (const u16 *)_a;
  70         const u16 *b = (const u16 *)_b;
  71         const u16 *mask = (const u16 *)_mask;
  72         int i;
  73
  74         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  75                 ret |= (a[i] ^ b[i]) & mask[i];
  76 #endif
  77         return ret;
  78 }
  79
  80 /* Returns whether packet matches rule or not. */
  81 static inline int arp_packet_match(const struct arphdr *arphdr,
  82                                    struct net_device *dev,
  83                                    const char *indev,
  84                                    const char *outdev,
  85                                    const struct arpt_arp *arpinfo)
  86 {
  87         const char *arpptr = (char *)(arphdr + 1);
  88         const char *src_devaddr, *tgt_devaddr;
  89         __be32 src_ipaddr, tgt_ipaddr;
  90         long ret;
  91
  92         if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
  93                     (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
  94                 return 0;
  95
  96         if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
  97                     (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
  98                 return 0;
  99
 100         if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
 101                     (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
 102                 return 0;
 103
 104         if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
 105                     (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
 106                 return 0;
 107
 108         src_devaddr = arpptr;
 109         arpptr += dev->addr_len;
 110         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 111         arpptr += sizeof(u32);
 112         tgt_devaddr = arpptr;
 113         arpptr += dev->addr_len;
 114         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 115
 116         if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
 117                     arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
 118                                         dev->addr_len)) ||
 119             NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
 120                     arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
 121                                         dev->addr_len)))
 122                 return 0;
 123
 124         if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
 125                     (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
 126             NF_INVF(arpinfo, ARPT_INV_TGTIP,
 127                     (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
 128                 return 0;
 129
 130         /* Look for ifname matches.  */
 131         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 132
 133         if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
 134                 return 0;
 135
 136         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 137
 138         if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
 139                 return 0;
 140
 141         return 1;
 142 }
 143
 144 static inline int arp_checkentry(const struct arpt_arp *arp)
 145 {
 146         if (arp->flags & ~ARPT_F_MASK)
 147                 return 0;
 148         if (arp->invflags & ~ARPT_INV_MASK)
 149                 return 0;
 150
 151         return 1;
 152 }
 153
 154 static unsigned int
 155 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 156 {
 157         net_err_ratelimited("arp_tables: error: '%s'\n",
 158                             (const char *)par->targinfo);
 159
 160         return NF_DROP;
 161 }
 162
 163 static inline const struct xt_entry_target *
 164 arpt_get_target_c(const struct arpt_entry *e)
 165 {
 166         return arpt_get_target((struct arpt_entry *)e);
 167 }
 168
 169 static inline struct arpt_entry *
 170 get_entry(const void *base, unsigned int offset)
 171 {
 172         return (struct arpt_entry *)(base + offset);
 173 }
 174
 175 static inline
 176 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 177 {
 178         return (void *)entry + entry->next_offset;
 179 }
 180
 181 unsigned int arpt_do_table(struct sk_buff *skb,
 182                            const struct nf_hook_state *state,
 183                            struct xt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 187         unsigned int verdict = NF_DROP;
 188         const struct arphdr *arp;
 189         struct arpt_entry *e, **jumpstack;
 190         const char *indev, *outdev;
 191         const void *table_base;
 192         unsigned int cpu, stackidx = 0;
 193         const struct xt_table_info *private;
 194         struct xt_action_param acpar;
 195         unsigned int addend;
 196
 197         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 198                 return NF_DROP;
 199
 200         indev = state->in ? state->in->name : nulldevname;
 201         outdev = state->out ? state->out->name : nulldevname;
 202
 203         local_bh_disable();
 204         addend = xt_write_recseq_begin();
 205         private = 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                                 if ((strcmp(t->target.u.user.name,
 338                                             XT_STANDARD_TARGET) == 0) &&
 339                                     t->verdict < -NF_MAX_VERDICT - 1)
 340                                         return 0;
 341
 342                                 /* Return: backtrack through the last
 343                                  * big jump.
 344                                  */
 345                                 do {
 346                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 347                                         oldpos = pos;
 348                                         pos = e->counters.pcnt;
 349                                         e->counters.pcnt = 0;
 350
 351                                         /* We're at the start. */
 352                                         if (pos == oldpos)
 353                                                 goto next;
 354
 355                                         e = entry0 + pos;
 356                                 } while (oldpos == pos + e->next_offset);
 357
 358                                 /* Move along one */
 359                                 size = e->next_offset;
 360                                 e = entry0 + pos + size;
 361                                 if (pos + size >= newinfo->size)
 362                                         return 0;
 363                                 e->counters.pcnt = pos;
 364                                 pos += size;
 365                         } else {
 366                                 int newpos = t->verdict;
 367
 368                                 if (strcmp(t->target.u.user.name,
 369                                            XT_STANDARD_TARGET) == 0 &&
 370                                     newpos >= 0) {
 371                                         /* This a jump; chase it. */
 372                                         if (!xt_find_jump_offset(offsets, newpos,
 373                                                                  newinfo->number))
 374                                                 return 0;
 375                                 } else {
 376                                         /* ... this is a fallthru */
 377                                         newpos = pos + e->next_offset;
 378                                         if (newpos >= newinfo->size)
 379                                                 return 0;
 380                                 }
 381                                 e = entry0 + newpos;
 382                                 e->counters.pcnt = pos;
 383                                 pos = newpos;
 384                         }
 385                 }
 386 next:           ;
 387         }
 388         return 1;
 389 }
 390
 391 static inline int check_target(struct arpt_entry *e, const char *name)
 392 {
 393         struct xt_entry_target *t = arpt_get_target(e);
 394         struct xt_tgchk_param par = {
 395                 .table     = name,
 396                 .entryinfo = e,
 397                 .target    = t->u.kernel.target,
 398                 .targinfo  = t->data,
 399                 .hook_mask = e->comefrom,
 400                 .family    = NFPROTO_ARP,
 401         };
 402
 403         return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 404 }
 405
 406 static inline int
 407 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 408                  struct xt_percpu_counter_alloc_state *alloc_state)
 409 {
 410         struct xt_entry_target *t;
 411         struct xt_target *target;
 412         int ret;
 413
 414         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 415                 return -ENOMEM;
 416
 417         t = arpt_get_target(e);
 418         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 419                                         t->u.user.revision);
 420         if (IS_ERR(target)) {
 421                 ret = PTR_ERR(target);
 422                 goto out;
 423         }
 424         t->u.kernel.target = target;
 425
 426         ret = check_target(e, name);
 427         if (ret)
 428                 goto err;
 429         return 0;
 430 err:
 431         module_put(t->u.kernel.target->me);
 432 out:
 433         xt_percpu_counter_free(&e->counters);
 434
 435         return ret;
 436 }
 437
 438 static bool check_underflow(const struct arpt_entry *e)
 439 {
 440         const struct xt_entry_target *t;
 441         unsigned int verdict;
 442
 443         if (!unconditional(e))
 444                 return false;
 445         t = arpt_get_target_c(e);
 446         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 447                 return false;
 448         verdict = ((struct xt_standard_target *)t)->verdict;
 449         verdict = -verdict - 1;
 450         return verdict == NF_DROP || verdict == NF_ACCEPT;
 451 }
 452
 453 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 454                                              struct xt_table_info *newinfo,
 455                                              const unsigned char *base,
 456                                              const unsigned char *limit,
 457                                              const unsigned int *hook_entries,
 458                                              const unsigned int *underflows,
 459                                              unsigned int valid_hooks)
 460 {
 461         unsigned int h;
 462         int err;
 463
 464         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 465             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 466             (unsigned char *)e + e->next_offset > limit)
 467                 return -EINVAL;
 468
 469         if (e->next_offset
 470             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
 471                 return -EINVAL;
 472
 473         if (!arp_checkentry(&e->arp))
 474                 return -EINVAL;
 475
 476         err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 477                                      e->next_offset);
 478         if (err)
 479                 return err;
 480
 481         /* Check hooks & underflows */
 482         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 483                 if (!(valid_hooks & (1 << h)))
 484                         continue;
 485                 if ((unsigned char *)e - base == hook_entries[h])
 486                         newinfo->hook_entry[h] = hook_entries[h];
 487                 if ((unsigned char *)e - base == underflows[h]) {
 488                         if (!check_underflow(e))
 489                                 return -EINVAL;
 490
 491                         newinfo->underflow[h] = underflows[h];
 492                 }
 493         }
 494
 495         /* Clear counters and comefrom */
 496         e->counters = ((struct xt_counters) { 0, 0 });
 497         e->comefrom = 0;
 498         return 0;
 499 }
 500
 501 static inline void cleanup_entry(struct arpt_entry *e)
 502 {
 503         struct xt_tgdtor_param par;
 504         struct xt_entry_target *t;
 505
 506         t = arpt_get_target(e);
 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 xt_table_info *newinfo, void *entry0,
 520                            const struct arpt_replace *repl)
 521 {
 522         struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 523         struct arpt_entry *iter;
 524         unsigned int *offsets;
 525         unsigned int i;
 526         int ret = 0;
 527
 528         newinfo->size = repl->size;
 529         newinfo->number = repl->num_entries;
 530
 531         /* Init all hooks to impossible value. */
 532         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 533                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 534                 newinfo->underflow[i] = 0xFFFFFFFF;
 535         }
 536
 537         offsets = xt_alloc_entry_offsets(newinfo->number);
 538         if (!offsets)
 539                 return -ENOMEM;
 540         i = 0;
 541
 542         /* Walk through entries, checking offsets. */
 543         xt_entry_foreach(iter, entry0, newinfo->size) {
 544                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 545                                                  entry0 + repl->size,
 546                                                  repl->hook_entry,
 547                                                  repl->underflow,
 548                                                  repl->valid_hooks);
 549                 if (ret != 0)
 550                         goto out_free;
 551                 if (i < repl->num_entries)
 552                         offsets[i] = (void *)iter - entry0;
 553                 ++i;
 554                 if (strcmp(arpt_get_target(iter)->u.user.name,
 555                     XT_ERROR_TARGET) == 0)
 556                         ++newinfo->stacksize;
 557         }
 558
 559         ret = -EINVAL;
 560         if (i != repl->num_entries)
 561                 goto out_free;
 562
 563         /* Check hooks all assigned */
 564         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 565                 /* Only hooks which are valid */
 566                 if (!(repl->valid_hooks & (1 << i)))
 567                         continue;
 568                 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
 569                         goto out_free;
 570                 if (newinfo->underflow[i] == 0xFFFFFFFF)
 571                         goto out_free;
 572         }
 573
 574         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 575                 ret = -ELOOP;
 576                 goto out_free;
 577         }
 578         kvfree(offsets);
 579
 580         /* Finally, each sanity check must pass */
 581         i = 0;
 582         xt_entry_foreach(iter, entry0, newinfo->size) {
 583                 ret = find_check_entry(iter, repl->name, repl->size,
 584                                        &alloc_state);
 585                 if (ret != 0)
 586                         break;
 587                 ++i;
 588         }
 589
 590         if (ret != 0) {
 591                 xt_entry_foreach(iter, entry0, newinfo->size) {
 592                         if (i-- == 0)
 593                                 break;
 594                         cleanup_entry(iter);
 595                 }
 596                 return ret;
 597         }
 598
 599         return ret;
 600  out_free:
 601         kvfree(offsets);
 602         return ret;
 603 }
 604
 605 static void get_counters(const struct xt_table_info *t,
 606                          struct xt_counters counters[])
 607 {
 608         struct arpt_entry *iter;
 609         unsigned int cpu;
 610         unsigned int i;
 611
 612         for_each_possible_cpu(cpu) {
 613                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 614
 615                 i = 0;
 616                 xt_entry_foreach(iter, t->entries, t->size) {
 617                         struct xt_counters *tmp;
 618                         u64 bcnt, pcnt;
 619                         unsigned int start;
 620
 621                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 622                         do {
 623                                 start = read_seqcount_begin(s);
 624                                 bcnt = tmp->bcnt;
 625                                 pcnt = tmp->pcnt;
 626                         } while (read_seqcount_retry(s, start));
 627
 628                         ADD_COUNTER(counters[i], bcnt, pcnt);
 629                         ++i;
 630                         cond_resched();
 631                 }
 632         }
 633 }
 634
 635 static void get_old_counters(const struct xt_table_info *t,
 636                              struct xt_counters counters[])
 637 {
 638         struct arpt_entry *iter;
 639         unsigned int cpu, i;
 640
 641         for_each_possible_cpu(cpu) {
 642                 i = 0;
 643                 xt_entry_foreach(iter, t->entries, t->size) {
 644                         struct xt_counters *tmp;
 645
 646                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 647                         ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
 648                         ++i;
 649                 }
 650                 cond_resched();
 651         }
 652 }
 653
 654 static struct xt_counters *alloc_counters(const struct xt_table *table)
 655 {
 656         unsigned int countersize;
 657         struct xt_counters *counters;
 658         const struct xt_table_info *private = table->private;
 659
 660         /* We need atomic snapshot of counters: rest doesn't change
 661          * (other than comefrom, which userspace doesn't care
 662          * about).
 663          */
 664         countersize = sizeof(struct xt_counters) * private->number;
 665         counters = vzalloc(countersize);
 666
 667         if (counters == NULL)
 668                 return ERR_PTR(-ENOMEM);
 669
 670         get_counters(private, counters);
 671
 672         return counters;
 673 }
 674
 675 static int copy_entries_to_user(unsigned int total_size,
 676                                 const struct xt_table *table,
 677                                 void __user *userptr)
 678 {
 679         unsigned int off, num;
 680         const struct arpt_entry *e;
 681         struct xt_counters *counters;
 682         struct xt_table_info *private = table->private;
 683         int ret = 0;
 684         void *loc_cpu_entry;
 685
 686         counters = alloc_counters(table);
 687         if (IS_ERR(counters))
 688                 return PTR_ERR(counters);
 689
 690         loc_cpu_entry = private->entries;
 691
 692         /* FIXME: use iterator macros --RR */
 693         /* ... then go back and fix counters and names */
 694         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 695                 const struct xt_entry_target *t;
 696
 697                 e = loc_cpu_entry + off;
 698                 if (copy_to_user(userptr + off, e, sizeof(*e))) {
 699                         ret = -EFAULT;
 700                         goto free_counters;
 701                 }
 702                 if (copy_to_user(userptr + off
 703                                  + offsetof(struct arpt_entry, counters),
 704                                  &counters[num],
 705                                  sizeof(counters[num])) != 0) {
 706                         ret = -EFAULT;
 707                         goto free_counters;
 708                 }
 709
 710                 t = arpt_get_target_c(e);
 711                 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
 712                         ret = -EFAULT;
 713                         goto free_counters;
 714                 }
 715         }
 716
 717  free_counters:
 718         vfree(counters);
 719         return ret;
 720 }
 721
 722 #ifdef CONFIG_COMPAT
 723 static void compat_standard_from_user(void *dst, const void *src)
 724 {
 725         int v = *(compat_int_t *)src;
 726
 727         if (v > 0)
 728                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 729         memcpy(dst, &v, sizeof(v));
 730 }
 731
 732 static int compat_standard_to_user(void __user *dst, const void *src)
 733 {
 734         compat_int_t cv = *(int *)src;
 735
 736         if (cv > 0)
 737                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 738         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 739 }
 740
 741 static int compat_calc_entry(const struct arpt_entry *e,
 742                              const struct xt_table_info *info,
 743                              const void *base, struct xt_table_info *newinfo)
 744 {
 745         const struct xt_entry_target *t;
 746         unsigned int entry_offset;
 747         int off, i, ret;
 748
 749         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 750         entry_offset = (void *)e - base;
 751
 752         t = arpt_get_target_c(e);
 753         off += xt_compat_target_offset(t->u.kernel.target);
 754         newinfo->size -= off;
 755         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 756         if (ret)
 757                 return ret;
 758
 759         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 760                 if (info->hook_entry[i] &&
 761                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 762                         newinfo->hook_entry[i] -= off;
 763                 if (info->underflow[i] &&
 764                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 765                         newinfo->underflow[i] -= off;
 766         }
 767         return 0;
 768 }
 769
 770 static int compat_table_info(const struct xt_table_info *info,
 771                              struct xt_table_info *newinfo)
 772 {
 773         struct arpt_entry *iter;
 774         const void *loc_cpu_entry;
 775         int ret;
 776
 777         if (!newinfo || !info)
 778                 return -EINVAL;
 779
 780         /* we dont care about newinfo->entries */
 781         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 782         newinfo->initial_entries = 0;
 783         loc_cpu_entry = info->entries;
 784         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 785         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 786                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 787                 if (ret != 0)
 788                         return ret;
 789         }
 790         return 0;
 791 }
 792 #endif
 793
 794 static int get_info(struct net *net, void __user *user,
 795                     const int *len, int compat)
 796 {
 797         char name[XT_TABLE_MAXNAMELEN];
 798         struct xt_table *t;
 799         int ret;
 800
 801         if (*len != sizeof(struct arpt_getinfo))
 802                 return -EINVAL;
 803
 804         if (copy_from_user(name, user, sizeof(name)) != 0)
 805                 return -EFAULT;
 806
 807         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 808 #ifdef CONFIG_COMPAT
 809         if (compat)
 810                 xt_compat_lock(NFPROTO_ARP);
 811 #endif
 812         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 813         if (!IS_ERR(t)) {
 814                 struct arpt_getinfo info;
 815                 const struct xt_table_info *private = t->private;
 816 #ifdef CONFIG_COMPAT
 817                 struct xt_table_info tmp;
 818
 819                 if (compat) {
 820                         ret = compat_table_info(private, &tmp);
 821                         xt_compat_flush_offsets(NFPROTO_ARP);
 822                         private = &tmp;
 823                 }
 824 #endif
 825                 memset(&info, 0, sizeof(info));
 826                 info.valid_hooks = t->valid_hooks;
 827                 memcpy(info.hook_entry, private->hook_entry,
 828                        sizeof(info.hook_entry));
 829                 memcpy(info.underflow, private->underflow,
 830                        sizeof(info.underflow));
 831                 info.num_entries = private->number;
 832                 info.size = private->size;
 833                 strcpy(info.name, name);
 834
 835                 if (copy_to_user(user, &info, *len) != 0)
 836                         ret = -EFAULT;
 837                 else
 838                         ret = 0;
 839                 xt_table_unlock(t);
 840                 module_put(t->me);
 841         } else
 842                 ret = PTR_ERR(t);
 843 #ifdef CONFIG_COMPAT
 844         if (compat)
 845                 xt_compat_unlock(NFPROTO_ARP);
 846 #endif
 847         return ret;
 848 }
 849
 850 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 851                        const int *len)
 852 {
 853         int ret;
 854         struct arpt_get_entries get;
 855         struct xt_table *t;
 856
 857         if (*len < sizeof(get))
 858                 return -EINVAL;
 859         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 860                 return -EFAULT;
 861         if (*len != sizeof(struct arpt_get_entries) + get.size)
 862                 return -EINVAL;
 863
 864         get.name[sizeof(get.name) - 1] = '\0';
 865
 866         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 867         if (!IS_ERR(t)) {
 868                 const struct xt_table_info *private = t->private;
 869
 870                 if (get.size == private->size)
 871                         ret = copy_entries_to_user(private->size,
 872                                                    t, uptr->entrytable);
 873                 else
 874                         ret = -EAGAIN;
 875
 876                 module_put(t->me);
 877                 xt_table_unlock(t);
 878         } else
 879                 ret = PTR_ERR(t);
 880
 881         return ret;
 882 }
 883
 884 static int __do_replace(struct net *net, const char *name,
 885                         unsigned int valid_hooks,
 886                         struct xt_table_info *newinfo,
 887                         unsigned int num_counters,
 888                         void __user *counters_ptr)
 889 {
 890         int ret;
 891         struct xt_table *t;
 892         struct xt_table_info *oldinfo;
 893         struct xt_counters *counters;
 894         void *loc_cpu_old_entry;
 895         struct arpt_entry *iter;
 896
 897         ret = 0;
 898         counters = vzalloc(num_counters * sizeof(struct xt_counters));
 899         if (!counters) {
 900                 ret = -ENOMEM;
 901                 goto out;
 902         }
 903
 904         t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
 905         if (IS_ERR(t)) {
 906                 ret = PTR_ERR(t);
 907                 goto free_newinfo_counters_untrans;
 908         }
 909
 910         /* You lied! */
 911         if (valid_hooks != t->valid_hooks) {
 912                 ret = -EINVAL;
 913                 goto put_module;
 914         }
 915
 916         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
 917         if (!oldinfo)
 918                 goto put_module;
 919
 920         /* Update module usage count based on number of rules */
 921         if ((oldinfo->number > oldinfo->initial_entries) ||
 922             (newinfo->number <= oldinfo->initial_entries))
 923                 module_put(t->me);
 924         if ((oldinfo->number > oldinfo->initial_entries) &&
 925             (newinfo->number <= oldinfo->initial_entries))
 926                 module_put(t->me);
 927
 928         get_old_counters(oldinfo, counters);
 929
 930         /* Decrease module usage counts and free resource */
 931         loc_cpu_old_entry = oldinfo->entries;
 932         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
 933                 cleanup_entry(iter);
 934
 935         xt_free_table_info(oldinfo);
 936         if (copy_to_user(counters_ptr, counters,
 937                          sizeof(struct xt_counters) * num_counters) != 0) {
 938                 /* Silent error, can't fail, new table is already in place */
 939                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
 940         }
 941         vfree(counters);
 942         xt_table_unlock(t);
 943         return ret;
 944
 945  put_module:
 946         module_put(t->me);
 947         xt_table_unlock(t);
 948  free_newinfo_counters_untrans:
 949         vfree(counters);
 950  out:
 951         return ret;
 952 }
 953
 954 static int do_replace(struct net *net, const void __user *user,
 955                       unsigned int len)
 956 {
 957         int ret;
 958         struct arpt_replace tmp;
 959         struct xt_table_info *newinfo;
 960         void *loc_cpu_entry;
 961         struct arpt_entry *iter;
 962
 963         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 964                 return -EFAULT;
 965
 966         /* overflow check */
 967         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 968                 return -ENOMEM;
 969         if (tmp.num_counters == 0)
 970                 return -EINVAL;
 971
 972         tmp.name[sizeof(tmp.name)-1] = 0;
 973
 974         newinfo = xt_alloc_table_info(tmp.size);
 975         if (!newinfo)
 976                 return -ENOMEM;
 977
 978         loc_cpu_entry = newinfo->entries;
 979         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 980                            tmp.size) != 0) {
 981                 ret = -EFAULT;
 982                 goto free_newinfo;
 983         }
 984
 985         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
 986         if (ret != 0)
 987                 goto free_newinfo;
 988
 989         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
 990                            tmp.num_counters, tmp.counters);
 991         if (ret)
 992                 goto free_newinfo_untrans;
 993         return 0;
 994
 995  free_newinfo_untrans:
 996         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
 997                 cleanup_entry(iter);
 998  free_newinfo:
 999         xt_free_table_info(newinfo);
1000         return ret;
1001 }
1002
1003 static int do_add_counters(struct net *net, const void __user *user,
1004                            unsigned int len, int compat)
1005 {
1006         unsigned int i;
1007         struct xt_counters_info tmp;
1008         struct xt_counters *paddc;
1009         struct xt_table *t;
1010         const struct xt_table_info *private;
1011         int ret = 0;
1012         struct arpt_entry *iter;
1013         unsigned int addend;
1014
1015         paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1016         if (IS_ERR(paddc))
1017                 return PTR_ERR(paddc);
1018
1019         t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1020         if (IS_ERR(t)) {
1021                 ret = PTR_ERR(t);
1022                 goto free;
1023         }
1024
1025         local_bh_disable();
1026         private = t->private;
1027         if (private->number != tmp.num_counters) {
1028                 ret = -EINVAL;
1029                 goto unlock_up_free;
1030         }
1031
1032         i = 0;
1033
1034         addend = xt_write_recseq_begin();
1035         xt_entry_foreach(iter,  private->entries, private->size) {
1036                 struct xt_counters *tmp;
1037
1038                 tmp = xt_get_this_cpu_counter(&iter->counters);
1039                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1040                 ++i;
1041         }
1042         xt_write_recseq_end(addend);
1043  unlock_up_free:
1044         local_bh_enable();
1045         xt_table_unlock(t);
1046         module_put(t->me);
1047  free:
1048         vfree(paddc);
1049
1050         return ret;
1051 }
1052
1053 #ifdef CONFIG_COMPAT
1054 struct compat_arpt_replace {
1055         char                            name[XT_TABLE_MAXNAMELEN];
1056         u32                             valid_hooks;
1057         u32                             num_entries;
1058         u32                             size;
1059         u32                             hook_entry[NF_ARP_NUMHOOKS];
1060         u32                             underflow[NF_ARP_NUMHOOKS];
1061         u32                             num_counters;
1062         compat_uptr_t                   counters;
1063         struct compat_arpt_entry        entries[0];
1064 };
1065
1066 static inline void compat_release_entry(struct compat_arpt_entry *e)
1067 {
1068         struct xt_entry_target *t;
1069
1070         t = compat_arpt_get_target(e);
1071         module_put(t->u.kernel.target->me);
1072 }
1073
1074 static int
1075 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1076                                   struct xt_table_info *newinfo,
1077                                   unsigned int *size,
1078                                   const unsigned char *base,
1079                                   const unsigned char *limit)
1080 {
1081         struct xt_entry_target *t;
1082         struct xt_target *target;
1083         unsigned int entry_offset;
1084         int ret, off;
1085
1086         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1087             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1088             (unsigned char *)e + e->next_offset > limit)
1089                 return -EINVAL;
1090
1091         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1092                              sizeof(struct compat_xt_entry_target))
1093                 return -EINVAL;
1094
1095         if (!arp_checkentry(&e->arp))
1096                 return -EINVAL;
1097
1098         ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1099                                             e->next_offset);
1100         if (ret)
1101                 return ret;
1102
1103         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1104         entry_offset = (void *)e - (void *)base;
1105
1106         t = compat_arpt_get_target(e);
1107         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1108                                         t->u.user.revision);
1109         if (IS_ERR(target)) {
1110                 ret = PTR_ERR(target);
1111                 goto out;
1112         }
1113         t->u.kernel.target = target;
1114
1115         off += xt_compat_target_offset(target);
1116         *size += off;
1117         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1118         if (ret)
1119                 goto release_target;
1120
1121         return 0;
1122
1123 release_target:
1124         module_put(t->u.kernel.target->me);
1125 out:
1126         return ret;
1127 }
1128
1129 static void
1130 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1131                             unsigned int *size,
1132                             struct xt_table_info *newinfo, unsigned char *base)
1133 {
1134         struct xt_entry_target *t;
1135         struct arpt_entry *de;
1136         unsigned int origsize;
1137         int h;
1138
1139         origsize = *size;
1140         de = *dstptr;
1141         memcpy(de, e, sizeof(struct arpt_entry));
1142         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1143
1144         *dstptr += sizeof(struct arpt_entry);
1145         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1146
1147         de->target_offset = e->target_offset - (origsize - *size);
1148         t = compat_arpt_get_target(e);
1149         xt_compat_target_from_user(t, dstptr, size);
1150
1151         de->next_offset = e->next_offset - (origsize - *size);
1152         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1153                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1154                         newinfo->hook_entry[h] -= origsize - *size;
1155                 if ((unsigned char *)de - base < newinfo->underflow[h])
1156                         newinfo->underflow[h] -= origsize - *size;
1157         }
1158 }
1159
1160 static int translate_compat_table(struct xt_table_info **pinfo,
1161                                   void **pentry0,
1162                                   const struct compat_arpt_replace *compatr)
1163 {
1164         unsigned int i, j;
1165         struct xt_table_info *newinfo, *info;
1166         void *pos, *entry0, *entry1;
1167         struct compat_arpt_entry *iter0;
1168         struct arpt_replace repl;
1169         unsigned int size;
1170         int ret = 0;
1171
1172         info = *pinfo;
1173         entry0 = *pentry0;
1174         size = compatr->size;
1175         info->number = compatr->num_entries;
1176
1177         j = 0;
1178         xt_compat_lock(NFPROTO_ARP);
1179         xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1180         /* Walk through entries, checking offsets. */
1181         xt_entry_foreach(iter0, entry0, compatr->size) {
1182                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1183                                                         entry0,
1184                                                         entry0 + compatr->size);
1185                 if (ret != 0)
1186                         goto out_unlock;
1187                 ++j;
1188         }
1189
1190         ret = -EINVAL;
1191         if (j != compatr->num_entries)
1192                 goto out_unlock;
1193
1194         ret = -ENOMEM;
1195         newinfo = xt_alloc_table_info(size);
1196         if (!newinfo)
1197                 goto out_unlock;
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(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, void __user *user,
1250                              unsigned int len)
1251 {
1252         int ret;
1253         struct compat_arpt_replace tmp;
1254         struct xt_table_info *newinfo;
1255         void *loc_cpu_entry;
1256         struct arpt_entry *iter;
1257
1258         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1259                 return -EFAULT;
1260
1261         /* overflow check */
1262         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1263                 return -ENOMEM;
1264         if (tmp.num_counters == 0)
1265                 return -EINVAL;
1266
1267         tmp.name[sizeof(tmp.name)-1] = 0;
1268
1269         newinfo = xt_alloc_table_info(tmp.size);
1270         if (!newinfo)
1271                 return -ENOMEM;
1272
1273         loc_cpu_entry = newinfo->entries;
1274         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1275                 ret = -EFAULT;
1276                 goto free_newinfo;
1277         }
1278
1279         ret = translate_compat_table(&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);
1292  free_newinfo:
1293         xt_free_table_info(newinfo);
1294         return ret;
1295 }
1296
1297 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1298                                   unsigned int len)
1299 {
1300         int ret;
1301
1302         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1303                 return -EPERM;
1304
1305         switch (cmd) {
1306         case ARPT_SO_SET_REPLACE:
1307                 ret = compat_do_replace(sock_net(sk), user, len);
1308                 break;
1309
1310         case ARPT_SO_SET_ADD_COUNTERS:
1311                 ret = do_add_counters(sock_net(sk), user, len, 1);
1312                 break;
1313
1314         default:
1315                 ret = -EINVAL;
1316         }
1317
1318         return ret;
1319 }
1320
1321 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1322                                      compat_uint_t *size,
1323                                      struct xt_counters *counters,
1324                                      unsigned int i)
1325 {
1326         struct xt_entry_target *t;
1327         struct compat_arpt_entry __user *ce;
1328         u_int16_t target_offset, next_offset;
1329         compat_uint_t origsize;
1330         int ret;
1331
1332         origsize = *size;
1333         ce = *dstptr;
1334         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1335             copy_to_user(&ce->counters, &counters[i],
1336             sizeof(counters[i])) != 0)
1337                 return -EFAULT;
1338
1339         *dstptr += sizeof(struct compat_arpt_entry);
1340         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1341
1342         target_offset = e->target_offset - (origsize - *size);
1343
1344         t = arpt_get_target(e);
1345         ret = xt_compat_target_to_user(t, dstptr, size);
1346         if (ret)
1347                 return ret;
1348         next_offset = e->next_offset - (origsize - *size);
1349         if (put_user(target_offset, &ce->target_offset) != 0 ||
1350             put_user(next_offset, &ce->next_offset) != 0)
1351                 return -EFAULT;
1352         return 0;
1353 }
1354
1355 static int compat_copy_entries_to_user(unsigned int total_size,
1356                                        struct xt_table *table,
1357                                        void __user *userptr)
1358 {
1359         struct xt_counters *counters;
1360         const struct xt_table_info *private = table->private;
1361         void __user *pos;
1362         unsigned int size;
1363         int ret = 0;
1364         unsigned int i = 0;
1365         struct arpt_entry *iter;
1366
1367         counters = alloc_counters(table);
1368         if (IS_ERR(counters))
1369                 return PTR_ERR(counters);
1370
1371         pos = userptr;
1372         size = total_size;
1373         xt_entry_foreach(iter, private->entries, total_size) {
1374                 ret = compat_copy_entry_to_user(iter, &pos,
1375                                                 &size, counters, i++);
1376                 if (ret != 0)
1377                         break;
1378         }
1379         vfree(counters);
1380         return ret;
1381 }
1382
1383 struct compat_arpt_get_entries {
1384         char name[XT_TABLE_MAXNAMELEN];
1385         compat_uint_t size;
1386         struct compat_arpt_entry entrytable[0];
1387 };
1388
1389 static int compat_get_entries(struct net *net,
1390                               struct compat_arpt_get_entries __user *uptr,
1391                               int *len)
1392 {
1393         int ret;
1394         struct compat_arpt_get_entries get;
1395         struct xt_table *t;
1396
1397         if (*len < sizeof(get))
1398                 return -EINVAL;
1399         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1400                 return -EFAULT;
1401         if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
1402                 return -EINVAL;
1403
1404         get.name[sizeof(get.name) - 1] = '\0';
1405
1406         xt_compat_lock(NFPROTO_ARP);
1407         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1408         if (!IS_ERR(t)) {
1409                 const struct xt_table_info *private = t->private;
1410                 struct xt_table_info info;
1411
1412                 ret = compat_table_info(private, &info);
1413                 if (!ret && get.size == info.size) {
1414                         ret = compat_copy_entries_to_user(private->size,
1415                                                           t, uptr->entrytable);
1416                 } else if (!ret)
1417                         ret = -EAGAIN;
1418
1419                 xt_compat_flush_offsets(NFPROTO_ARP);
1420                 module_put(t->me);
1421                 xt_table_unlock(t);
1422         } else
1423                 ret = PTR_ERR(t);
1424
1425         xt_compat_unlock(NFPROTO_ARP);
1426         return ret;
1427 }
1428
1429 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1430
1431 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1432                                   int *len)
1433 {
1434         int ret;
1435
1436         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1437                 return -EPERM;
1438
1439         switch (cmd) {
1440         case ARPT_SO_GET_INFO:
1441                 ret = get_info(sock_net(sk), user, len, 1);
1442                 break;
1443         case ARPT_SO_GET_ENTRIES:
1444                 ret = compat_get_entries(sock_net(sk), user, len);
1445                 break;
1446         default:
1447                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1448         }
1449         return ret;
1450 }
1451 #endif
1452
1453 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1454 {
1455         int ret;
1456
1457         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1458                 return -EPERM;
1459
1460         switch (cmd) {
1461         case ARPT_SO_SET_REPLACE:
1462                 ret = do_replace(sock_net(sk), user, len);
1463                 break;
1464
1465         case ARPT_SO_SET_ADD_COUNTERS:
1466                 ret = do_add_counters(sock_net(sk), user, len, 0);
1467                 break;
1468
1469         default:
1470                 ret = -EINVAL;
1471         }
1472
1473         return ret;
1474 }
1475
1476 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1477 {
1478         int ret;
1479
1480         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1481                 return -EPERM;
1482
1483         switch (cmd) {
1484         case ARPT_SO_GET_INFO:
1485                 ret = get_info(sock_net(sk), user, len, 0);
1486                 break;
1487
1488         case ARPT_SO_GET_ENTRIES:
1489                 ret = get_entries(sock_net(sk), user, len);
1490                 break;
1491
1492         case ARPT_SO_GET_REVISION_TARGET: {
1493                 struct xt_get_revision rev;
1494
1495                 if (*len != sizeof(rev)) {
1496                         ret = -EINVAL;
1497                         break;
1498                 }
1499                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1500                         ret = -EFAULT;
1501                         break;
1502                 }
1503                 rev.name[sizeof(rev.name)-1] = 0;
1504
1505                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1506                                                          rev.revision, 1, &ret),
1507                                         "arpt_%s", rev.name);
1508                 break;
1509         }
1510
1511         default:
1512                 ret = -EINVAL;
1513         }
1514
1515         return ret;
1516 }
1517
1518 static void __arpt_unregister_table(struct xt_table *table)
1519 {
1520         struct xt_table_info *private;
1521         void *loc_cpu_entry;
1522         struct module *table_owner = table->me;
1523         struct arpt_entry *iter;
1524
1525         private = xt_unregister_table(table);
1526
1527         /* Decrease module usage counts and free resources */
1528         loc_cpu_entry = private->entries;
1529         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1530                 cleanup_entry(iter);
1531         if (private->number > private->initial_entries)
1532                 module_put(table_owner);
1533         xt_free_table_info(private);
1534 }
1535
1536 int arpt_register_table(struct net *net,
1537                         const struct xt_table *table,
1538                         const struct arpt_replace *repl,
1539                         const struct nf_hook_ops *ops,
1540                         struct xt_table **res)
1541 {
1542         int ret;
1543         struct xt_table_info *newinfo;
1544         struct xt_table_info bootstrap = {0};
1545         void *loc_cpu_entry;
1546         struct xt_table *new_table;
1547
1548         newinfo = xt_alloc_table_info(repl->size);
1549         if (!newinfo)
1550                 return -ENOMEM;
1551
1552         loc_cpu_entry = newinfo->entries;
1553         memcpy(loc_cpu_entry, repl->entries, repl->size);
1554
1555         ret = translate_table(newinfo, loc_cpu_entry, repl);
1556         if (ret != 0)
1557                 goto out_free;
1558
1559         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1560         if (IS_ERR(new_table)) {
1561                 ret = PTR_ERR(new_table);
1562                 goto out_free;
1563         }
1564
1565         /* set res now, will see skbs right after nf_register_net_hooks */
1566         WRITE_ONCE(*res, new_table);
1567
1568         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1569         if (ret != 0) {
1570                 __arpt_unregister_table(new_table);
1571                 *res = NULL;
1572         }
1573
1574         return ret;
1575
1576 out_free:
1577         xt_free_table_info(newinfo);
1578         return ret;
1579 }
1580
1581 void arpt_unregister_table(struct net *net, struct xt_table *table,
1582                            const struct nf_hook_ops *ops)
1583 {
1584         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1585         __arpt_unregister_table(table);
1586 }
1587
1588 /* The built-in targets: standard (NULL) and error. */
1589 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1590         {
1591                 .name             = XT_STANDARD_TARGET,
1592                 .targetsize       = sizeof(int),
1593                 .family           = NFPROTO_ARP,
1594 #ifdef CONFIG_COMPAT
1595                 .compatsize       = sizeof(compat_int_t),
1596                 .compat_from_user = compat_standard_from_user,
1597                 .compat_to_user   = compat_standard_to_user,
1598 #endif
1599         },
1600         {
1601                 .name             = XT_ERROR_TARGET,
1602                 .target           = arpt_error,
1603                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1604                 .family           = NFPROTO_ARP,
1605         },
1606 };
1607
1608 static struct nf_sockopt_ops arpt_sockopts = {
1609         .pf             = PF_INET,
1610         .set_optmin     = ARPT_BASE_CTL,
1611         .set_optmax     = ARPT_SO_SET_MAX+1,
1612         .set            = do_arpt_set_ctl,
1613 #ifdef CONFIG_COMPAT
1614         .compat_set     = compat_do_arpt_set_ctl,
1615 #endif
1616         .get_optmin     = ARPT_BASE_CTL,
1617         .get_optmax     = ARPT_SO_GET_MAX+1,
1618         .get            = do_arpt_get_ctl,
1619 #ifdef CONFIG_COMPAT
1620         .compat_get     = compat_do_arpt_get_ctl,
1621 #endif
1622         .owner          = THIS_MODULE,
1623 };
1624
1625 static int __net_init arp_tables_net_init(struct net *net)
1626 {
1627         return xt_proto_init(net, NFPROTO_ARP);
1628 }
1629
1630 static void __net_exit arp_tables_net_exit(struct net *net)
1631 {
1632         xt_proto_fini(net, NFPROTO_ARP);
1633 }
1634
1635 static struct pernet_operations arp_tables_net_ops = {
1636         .init = arp_tables_net_init,
1637         .exit = arp_tables_net_exit,
1638 };
1639
1640 static int __init arp_tables_init(void)
1641 {
1642         int ret;
1643
1644         ret = register_pernet_subsys(&arp_tables_net_ops);
1645         if (ret < 0)
1646                 goto err1;
1647
1648         /* No one else will be downing sem now, so we won't sleep */
1649         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1650         if (ret < 0)
1651                 goto err2;
1652
1653         /* Register setsockopt */
1654         ret = nf_register_sockopt(&arpt_sockopts);
1655         if (ret < 0)
1656                 goto err4;
1657
1658         return 0;
1659
1660 err4:
1661         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1662 err2:
1663         unregister_pernet_subsys(&arp_tables_net_ops);
1664 err1:
1665         return ret;
1666 }
1667
1668 static void __exit arp_tables_fini(void)
1669 {
1670         nf_unregister_sockopt(&arpt_sockopts);
1671         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1672         unregister_pernet_subsys(&arp_tables_net_ops);
1673 }
1674
1675 EXPORT_SYMBOL(arpt_register_table);
1676 EXPORT_SYMBOL(arpt_unregister_table);
1677 EXPORT_SYMBOL(arpt_do_table);
1678
1679 module_init(arp_tables_init);
1680 module_exit(arp_tables_fini);