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 <asm/uaccess.h>
  28
  29 #include <linux/netfilter/x_tables.h>
  30 #include <linux/netfilter_arp/arp_tables.h>
  31 #include "../../netfilter/xt_repldata.h"
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  35 MODULE_DESCRIPTION("arptables core");
  36
  37 /*#define DEBUG_ARP_TABLES*/
  38 /*#define DEBUG_ARP_TABLES_USER*/
  39
  40 #ifdef DEBUG_ARP_TABLES
  41 #define dprintf(format, args...)  pr_debug(format, ## args)
  42 #else
  43 #define dprintf(format, args...)
  44 #endif
  45
  46 #ifdef DEBUG_ARP_TABLES_USER
  47 #define duprintf(format, args...) pr_debug(format, ## args)
  48 #else
  49 #define duprintf(format, args...)
  50 #endif
  51
  52 #ifdef CONFIG_NETFILTER_DEBUG
  53 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  54 #else
  55 #define ARP_NF_ASSERT(x)
  56 #endif
  57
  58 void *arpt_alloc_initial_table(const struct xt_table *info)
  59 {
  60         return xt_alloc_initial_table(arpt, ARPT);
  61 }
  62 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  63
  64 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  65                                       const char *hdr_addr, int len)
  66 {
  67         int i, ret;
  68
  69         if (len > ARPT_DEV_ADDR_LEN_MAX)
  70                 len = ARPT_DEV_ADDR_LEN_MAX;
  71
  72         ret = 0;
  73         for (i = 0; i < len; i++)
  74                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  75
  76         return ret != 0;
  77 }
  78
  79 /*
  80  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  81  * Some arches dont care, unrolling the loop is a win on them.
  82  * For other arches, we only have a 16bit alignement.
  83  */
  84 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  85 {
  86 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  87         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  88 #else
  89         unsigned long ret = 0;
  90         const u16 *a = (const u16 *)_a;
  91         const u16 *b = (const u16 *)_b;
  92         const u16 *mask = (const u16 *)_mask;
  93         int i;
  94
  95         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  96                 ret |= (a[i] ^ b[i]) & mask[i];
  97 #endif
  98         return ret;
  99 }
 100
 101 /* Returns whether packet matches rule or not. */
 102 static inline int arp_packet_match(const struct arphdr *arphdr,
 103                                    struct net_device *dev,
 104                                    const char *indev,
 105                                    const char *outdev,
 106                                    const struct arpt_arp *arpinfo)
 107 {
 108         const char *arpptr = (char *)(arphdr + 1);
 109         const char *src_devaddr, *tgt_devaddr;
 110         __be32 src_ipaddr, tgt_ipaddr;
 111         long ret;
 112
 113 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 114
 115         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 116                   ARPT_INV_ARPOP)) {
 117                 dprintf("ARP operation field mismatch.\n");
 118                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 119                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 120                 return 0;
 121         }
 122
 123         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 124                   ARPT_INV_ARPHRD)) {
 125                 dprintf("ARP hardware address format mismatch.\n");
 126                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 127                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 128                 return 0;
 129         }
 130
 131         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 132                   ARPT_INV_ARPPRO)) {
 133                 dprintf("ARP protocol address format mismatch.\n");
 134                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 135                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 136                 return 0;
 137         }
 138
 139         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 140                   ARPT_INV_ARPHLN)) {
 141                 dprintf("ARP hardware address length mismatch.\n");
 142                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 143                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 144                 return 0;
 145         }
 146
 147         src_devaddr = arpptr;
 148         arpptr += dev->addr_len;
 149         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 150         arpptr += sizeof(u32);
 151         tgt_devaddr = arpptr;
 152         arpptr += dev->addr_len;
 153         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 154
 155         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 156                   ARPT_INV_SRCDEVADDR) ||
 157             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 158                   ARPT_INV_TGTDEVADDR)) {
 159                 dprintf("Source or target device address mismatch.\n");
 160
 161                 return 0;
 162         }
 163
 164         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 165                   ARPT_INV_SRCIP) ||
 166             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 167                   ARPT_INV_TGTIP)) {
 168                 dprintf("Source or target IP address mismatch.\n");
 169
 170                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 171                         &src_ipaddr,
 172                         &arpinfo->smsk.s_addr,
 173                         &arpinfo->src.s_addr,
 174                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 175                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 176                         &tgt_ipaddr,
 177                         &arpinfo->tmsk.s_addr,
 178                         &arpinfo->tgt.s_addr,
 179                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 180                 return 0;
 181         }
 182
 183         /* Look for ifname matches.  */
 184         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 185
 186         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 187                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 188                         indev, arpinfo->iniface,
 189                         arpinfo->invflags & ARPT_INV_VIA_IN ? " (INV)" : "");
 190                 return 0;
 191         }
 192
 193         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 194
 195         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 196                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 197                         outdev, arpinfo->outiface,
 198                         arpinfo->invflags & ARPT_INV_VIA_OUT ? " (INV)" : "");
 199                 return 0;
 200         }
 201
 202         return 1;
 203 #undef FWINV
 204 }
 205
 206 static inline int arp_checkentry(const struct arpt_arp *arp)
 207 {
 208         if (arp->flags & ~ARPT_F_MASK) {
 209                 duprintf("Unknown flag bits set: %08X\n",
 210                          arp->flags & ~ARPT_F_MASK);
 211                 return 0;
 212         }
 213         if (arp->invflags & ~ARPT_INV_MASK) {
 214                 duprintf("Unknown invflag bits set: %08X\n",
 215                          arp->invflags & ~ARPT_INV_MASK);
 216                 return 0;
 217         }
 218
 219         return 1;
 220 }
 221
 222 static unsigned int
 223 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 224 {
 225         net_err_ratelimited("arp_tables: error: '%s'\n",
 226                             (const char *)par->targinfo);
 227
 228         return NF_DROP;
 229 }
 230
 231 static inline const struct xt_entry_target *
 232 arpt_get_target_c(const struct arpt_entry *e)
 233 {
 234         return arpt_get_target((struct arpt_entry *)e);
 235 }
 236
 237 static inline struct arpt_entry *
 238 get_entry(const void *base, unsigned int offset)
 239 {
 240         return (struct arpt_entry *)(base + offset);
 241 }
 242
 243 static inline
 244 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 245 {
 246         return (void *)entry + entry->next_offset;
 247 }
 248
 249 unsigned int arpt_do_table(struct sk_buff *skb,
 250                            const struct nf_hook_state *state,
 251                            struct xt_table *table)
 252 {
 253         unsigned int hook = state->hook;
 254         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 255         unsigned int verdict = NF_DROP;
 256         const struct arphdr *arp;
 257         struct arpt_entry *e, **jumpstack;
 258         const char *indev, *outdev;
 259         const void *table_base;
 260         unsigned int cpu, stackidx = 0;
 261         const struct xt_table_info *private;
 262         struct xt_action_param acpar;
 263         unsigned int addend;
 264
 265         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 266                 return NF_DROP;
 267
 268         indev = state->in ? state->in->name : nulldevname;
 269         outdev = state->out ? state->out->name : nulldevname;
 270
 271         local_bh_disable();
 272         addend = xt_write_recseq_begin();
 273         private = table->private;
 274         cpu     = smp_processor_id();
 275         /*
 276          * Ensure we load private-> members after we've fetched the base
 277          * pointer.
 278          */
 279         smp_read_barrier_depends();
 280         table_base = private->entries;
 281         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 282
 283         /* No TEE support for arptables, so no need to switch to alternate
 284          * stack.  All targets that reenter must return absolute verdicts.
 285          */
 286         e = get_entry(table_base, private->hook_entry[hook]);
 287
 288         acpar.net     = state->net;
 289         acpar.in      = state->in;
 290         acpar.out     = state->out;
 291         acpar.hooknum = hook;
 292         acpar.family  = NFPROTO_ARP;
 293         acpar.hotdrop = false;
 294
 295         arp = arp_hdr(skb);
 296         do {
 297                 const struct xt_entry_target *t;
 298                 struct xt_counters *counter;
 299
 300                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 301                         e = arpt_next_entry(e);
 302                         continue;
 303                 }
 304
 305                 counter = xt_get_this_cpu_counter(&e->counters);
 306                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 307
 308                 t = arpt_get_target_c(e);
 309
 310                 /* Standard target? */
 311                 if (!t->u.kernel.target->target) {
 312                         int v;
 313
 314                         v = ((struct xt_standard_target *)t)->verdict;
 315                         if (v < 0) {
 316                                 /* Pop from stack? */
 317                                 if (v != XT_RETURN) {
 318                                         verdict = (unsigned int)(-v) - 1;
 319                                         break;
 320                                 }
 321                                 if (stackidx == 0) {
 322                                         e = get_entry(table_base,
 323                                                       private->underflow[hook]);
 324                                 } else {
 325                                         e = jumpstack[--stackidx];
 326                                         e = arpt_next_entry(e);
 327                                 }
 328                                 continue;
 329                         }
 330                         if (table_base + v
 331                             != arpt_next_entry(e)) {
 332                                 jumpstack[stackidx++] = e;
 333                         }
 334
 335                         e = get_entry(table_base, v);
 336                         continue;
 337                 }
 338
 339                 acpar.target   = t->u.kernel.target;
 340                 acpar.targinfo = t->data;
 341                 verdict = t->u.kernel.target->target(skb, &acpar);
 342
 343                 /* Target might have changed stuff. */
 344                 arp = arp_hdr(skb);
 345
 346                 if (verdict == XT_CONTINUE)
 347                         e = arpt_next_entry(e);
 348                 else
 349                         /* Verdict */
 350                         break;
 351         } while (!acpar.hotdrop);
 352         xt_write_recseq_end(addend);
 353         local_bh_enable();
 354
 355         if (acpar.hotdrop)
 356                 return NF_DROP;
 357         else
 358                 return verdict;
 359 }
 360
 361 /* All zeroes == unconditional rule. */
 362 static inline bool unconditional(const struct arpt_entry *e)
 363 {
 364         static const struct arpt_arp uncond;
 365
 366         return e->target_offset == sizeof(struct arpt_entry) &&
 367                memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
 368 }
 369
 370 static bool find_jump_target(const struct xt_table_info *t,
 371                              const struct arpt_entry *target)
 372 {
 373         struct arpt_entry *iter;
 374
 375         xt_entry_foreach(iter, t->entries, t->size) {
 376                  if (iter == target)
 377                         return true;
 378         }
 379         return false;
 380 }
 381
 382 /* Figures out from what hook each rule can be called: returns 0 if
 383  * there are loops.  Puts hook bitmask in comefrom.
 384  */
 385 static int mark_source_chains(const struct xt_table_info *newinfo,
 386                               unsigned int valid_hooks, void *entry0)
 387 {
 388         unsigned int hook;
 389
 390         /* No recursion; use packet counter to save back ptrs (reset
 391          * to 0 as we leave), and comefrom to save source hook bitmask.
 392          */
 393         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 394                 unsigned int pos = newinfo->hook_entry[hook];
 395                 struct arpt_entry *e
 396                         = (struct arpt_entry *)(entry0 + pos);
 397
 398                 if (!(valid_hooks & (1 << hook)))
 399                         continue;
 400
 401                 /* Set initial back pointer. */
 402                 e->counters.pcnt = pos;
 403
 404                 for (;;) {
 405                         const struct xt_standard_target *t
 406                                 = (void *)arpt_get_target_c(e);
 407                         int visited = e->comefrom & (1 << hook);
 408
 409                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 410                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 411                                        hook, pos, e->comefrom);
 412                                 return 0;
 413                         }
 414                         e->comefrom
 415                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 416
 417                         /* Unconditional return/END. */
 418                         if ((unconditional(e) &&
 419                              (strcmp(t->target.u.user.name,
 420                                      XT_STANDARD_TARGET) == 0) &&
 421                              t->verdict < 0) || visited) {
 422                                 unsigned int oldpos, size;
 423
 424                                 if ((strcmp(t->target.u.user.name,
 425                                             XT_STANDARD_TARGET) == 0) &&
 426                                     t->verdict < -NF_MAX_VERDICT - 1) {
 427                                         duprintf("mark_source_chains: bad "
 428                                                 "negative verdict (%i)\n",
 429                                                                 t->verdict);
 430                                         return 0;
 431                                 }
 432
 433                                 /* Return: backtrack through the last
 434                                  * big jump.
 435                                  */
 436                                 do {
 437                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 438                                         oldpos = pos;
 439                                         pos = e->counters.pcnt;
 440                                         e->counters.pcnt = 0;
 441
 442                                         /* We're at the start. */
 443                                         if (pos == oldpos)
 444                                                 goto next;
 445
 446                                         e = (struct arpt_entry *)
 447                                                 (entry0 + pos);
 448                                 } while (oldpos == pos + e->next_offset);
 449
 450                                 /* Move along one */
 451                                 size = e->next_offset;
 452                                 e = (struct arpt_entry *)
 453                                         (entry0 + pos + size);
 454                                 if (pos + size >= newinfo->size)
 455                                         return 0;
 456                                 e->counters.pcnt = pos;
 457                                 pos += size;
 458                         } else {
 459                                 int newpos = t->verdict;
 460
 461                                 if (strcmp(t->target.u.user.name,
 462                                            XT_STANDARD_TARGET) == 0 &&
 463                                     newpos >= 0) {
 464                                         if (newpos > newinfo->size -
 465                                                 sizeof(struct arpt_entry)) {
 466                                                 duprintf("mark_source_chains: "
 467                                                         "bad verdict (%i)\n",
 468                                                                 newpos);
 469                                                 return 0;
 470                                         }
 471
 472                                         /* This a jump; chase it. */
 473                                         duprintf("Jump rule %u -> %u\n",
 474                                                  pos, newpos);
 475                                         e = (struct arpt_entry *)
 476                                                 (entry0 + newpos);
 477                                         if (!find_jump_target(newinfo, e))
 478                                                 return 0;
 479                                 } else {
 480                                         /* ... this is a fallthru */
 481                                         newpos = pos + e->next_offset;
 482                                         if (newpos >= newinfo->size)
 483                                                 return 0;
 484                                 }
 485                                 e = (struct arpt_entry *)
 486                                         (entry0 + newpos);
 487                                 e->counters.pcnt = pos;
 488                                 pos = newpos;
 489                         }
 490                 }
 491 next:
 492                 duprintf("Finished chain %u\n", hook);
 493         }
 494         return 1;
 495 }
 496
 497 static inline int check_entry(const struct arpt_entry *e)
 498 {
 499         if (!arp_checkentry(&e->arp))
 500                 return -EINVAL;
 501
 502         return xt_check_entry_offsets(e, e->target_offset, e->next_offset);
 503 }
 504
 505 static inline int check_target(struct arpt_entry *e, const char *name)
 506 {
 507         struct xt_entry_target *t = arpt_get_target(e);
 508         int ret;
 509         struct xt_tgchk_param par = {
 510                 .table     = name,
 511                 .entryinfo = e,
 512                 .target    = t->u.kernel.target,
 513                 .targinfo  = t->data,
 514                 .hook_mask = e->comefrom,
 515                 .family    = NFPROTO_ARP,
 516         };
 517
 518         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 519         if (ret < 0) {
 520                 duprintf("arp_tables: check failed for `%s'.\n",
 521                          t->u.kernel.target->name);
 522                 return ret;
 523         }
 524         return 0;
 525 }
 526
 527 static inline int
 528 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 529 {
 530         struct xt_entry_target *t;
 531         struct xt_target *target;
 532         int ret;
 533
 534         e->counters.pcnt = xt_percpu_counter_alloc();
 535         if (IS_ERR_VALUE(e->counters.pcnt))
 536                 return -ENOMEM;
 537
 538         t = arpt_get_target(e);
 539         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 540                                         t->u.user.revision);
 541         if (IS_ERR(target)) {
 542                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 543                 ret = PTR_ERR(target);
 544                 goto out;
 545         }
 546         t->u.kernel.target = target;
 547
 548         ret = check_target(e, name);
 549         if (ret)
 550                 goto err;
 551         return 0;
 552 err:
 553         module_put(t->u.kernel.target->me);
 554 out:
 555         xt_percpu_counter_free(e->counters.pcnt);
 556
 557         return ret;
 558 }
 559
 560 static bool check_underflow(const struct arpt_entry *e)
 561 {
 562         const struct xt_entry_target *t;
 563         unsigned int verdict;
 564
 565         if (!unconditional(e))
 566                 return false;
 567         t = arpt_get_target_c(e);
 568         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 569                 return false;
 570         verdict = ((struct xt_standard_target *)t)->verdict;
 571         verdict = -verdict - 1;
 572         return verdict == NF_DROP || verdict == NF_ACCEPT;
 573 }
 574
 575 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 576                                              struct xt_table_info *newinfo,
 577                                              const unsigned char *base,
 578                                              const unsigned char *limit,
 579                                              const unsigned int *hook_entries,
 580                                              const unsigned int *underflows,
 581                                              unsigned int valid_hooks)
 582 {
 583         unsigned int h;
 584         int err;
 585
 586         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 587             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 588             (unsigned char *)e + e->next_offset > limit) {
 589                 duprintf("Bad offset %p\n", e);
 590                 return -EINVAL;
 591         }
 592
 593         if (e->next_offset
 594             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 595                 duprintf("checking: element %p size %u\n",
 596                          e, e->next_offset);
 597                 return -EINVAL;
 598         }
 599
 600         err = check_entry(e);
 601         if (err)
 602                 return err;
 603
 604         /* Check hooks & underflows */
 605         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 606                 if (!(valid_hooks & (1 << h)))
 607                         continue;
 608                 if ((unsigned char *)e - base == hook_entries[h])
 609                         newinfo->hook_entry[h] = hook_entries[h];
 610                 if ((unsigned char *)e - base == underflows[h]) {
 611                         if (!check_underflow(e)) {
 612                                 pr_debug("Underflows must be unconditional and "
 613                                          "use the STANDARD target with "
 614                                          "ACCEPT/DROP\n");
 615                                 return -EINVAL;
 616                         }
 617                         newinfo->underflow[h] = underflows[h];
 618                 }
 619         }
 620
 621         /* Clear counters and comefrom */
 622         e->counters = ((struct xt_counters) { 0, 0 });
 623         e->comefrom = 0;
 624         return 0;
 625 }
 626
 627 static inline void cleanup_entry(struct arpt_entry *e)
 628 {
 629         struct xt_tgdtor_param par;
 630         struct xt_entry_target *t;
 631
 632         t = arpt_get_target(e);
 633         par.target   = t->u.kernel.target;
 634         par.targinfo = t->data;
 635         par.family   = NFPROTO_ARP;
 636         if (par.target->destroy != NULL)
 637                 par.target->destroy(&par);
 638         module_put(par.target->me);
 639         xt_percpu_counter_free(e->counters.pcnt);
 640 }
 641
 642 /* Checks and translates the user-supplied table segment (held in
 643  * newinfo).
 644  */
 645 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 646                            const struct arpt_replace *repl)
 647 {
 648         struct arpt_entry *iter;
 649         unsigned int i;
 650         int ret = 0;
 651
 652         newinfo->size = repl->size;
 653         newinfo->number = repl->num_entries;
 654
 655         /* Init all hooks to impossible value. */
 656         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 657                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 658                 newinfo->underflow[i] = 0xFFFFFFFF;
 659         }
 660
 661         duprintf("translate_table: size %u\n", newinfo->size);
 662         i = 0;
 663
 664         /* Walk through entries, checking offsets. */
 665         xt_entry_foreach(iter, entry0, newinfo->size) {
 666                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 667                                                  entry0 + repl->size,
 668                                                  repl->hook_entry,
 669                                                  repl->underflow,
 670                                                  repl->valid_hooks);
 671                 if (ret != 0)
 672                         break;
 673                 ++i;
 674                 if (strcmp(arpt_get_target(iter)->u.user.name,
 675                     XT_ERROR_TARGET) == 0)
 676                         ++newinfo->stacksize;
 677         }
 678         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 679         if (ret != 0)
 680                 return ret;
 681
 682         if (i != repl->num_entries) {
 683                 duprintf("translate_table: %u not %u entries\n",
 684                          i, repl->num_entries);
 685                 return -EINVAL;
 686         }
 687
 688         /* Check hooks all assigned */
 689         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 690                 /* Only hooks which are valid */
 691                 if (!(repl->valid_hooks & (1 << i)))
 692                         continue;
 693                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 694                         duprintf("Invalid hook entry %u %u\n",
 695                                  i, repl->hook_entry[i]);
 696                         return -EINVAL;
 697                 }
 698                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 699                         duprintf("Invalid underflow %u %u\n",
 700                                  i, repl->underflow[i]);
 701                         return -EINVAL;
 702                 }
 703         }
 704
 705         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
 706                 return -ELOOP;
 707
 708         /* Finally, each sanity check must pass */
 709         i = 0;
 710         xt_entry_foreach(iter, entry0, newinfo->size) {
 711                 ret = find_check_entry(iter, repl->name, repl->size);
 712                 if (ret != 0)
 713                         break;
 714                 ++i;
 715         }
 716
 717         if (ret != 0) {
 718                 xt_entry_foreach(iter, entry0, newinfo->size) {
 719                         if (i-- == 0)
 720                                 break;
 721                         cleanup_entry(iter);
 722                 }
 723                 return ret;
 724         }
 725
 726         return ret;
 727 }
 728
 729 static void get_counters(const struct xt_table_info *t,
 730                          struct xt_counters counters[])
 731 {
 732         struct arpt_entry *iter;
 733         unsigned int cpu;
 734         unsigned int i;
 735
 736         for_each_possible_cpu(cpu) {
 737                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 738
 739                 i = 0;
 740                 xt_entry_foreach(iter, t->entries, t->size) {
 741                         struct xt_counters *tmp;
 742                         u64 bcnt, pcnt;
 743                         unsigned int start;
 744
 745                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 746                         do {
 747                                 start = read_seqcount_begin(s);
 748                                 bcnt = tmp->bcnt;
 749                                 pcnt = tmp->pcnt;
 750                         } while (read_seqcount_retry(s, start));
 751
 752                         ADD_COUNTER(counters[i], bcnt, pcnt);
 753                         ++i;
 754                 }
 755         }
 756 }
 757
 758 static struct xt_counters *alloc_counters(const struct xt_table *table)
 759 {
 760         unsigned int countersize;
 761         struct xt_counters *counters;
 762         const struct xt_table_info *private = table->private;
 763
 764         /* We need atomic snapshot of counters: rest doesn't change
 765          * (other than comefrom, which userspace doesn't care
 766          * about).
 767          */
 768         countersize = sizeof(struct xt_counters) * private->number;
 769         counters = vzalloc(countersize);
 770
 771         if (counters == NULL)
 772                 return ERR_PTR(-ENOMEM);
 773
 774         get_counters(private, counters);
 775
 776         return counters;
 777 }
 778
 779 static int copy_entries_to_user(unsigned int total_size,
 780                                 const struct xt_table *table,
 781                                 void __user *userptr)
 782 {
 783         unsigned int off, num;
 784         const struct arpt_entry *e;
 785         struct xt_counters *counters;
 786         struct xt_table_info *private = table->private;
 787         int ret = 0;
 788         void *loc_cpu_entry;
 789
 790         counters = alloc_counters(table);
 791         if (IS_ERR(counters))
 792                 return PTR_ERR(counters);
 793
 794         loc_cpu_entry = private->entries;
 795         /* ... then copy entire thing ... */
 796         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 797                 ret = -EFAULT;
 798                 goto free_counters;
 799         }
 800
 801         /* FIXME: use iterator macros --RR */
 802         /* ... then go back and fix counters and names */
 803         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 804                 const struct xt_entry_target *t;
 805
 806                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 807                 if (copy_to_user(userptr + off
 808                                  + offsetof(struct arpt_entry, counters),
 809                                  &counters[num],
 810                                  sizeof(counters[num])) != 0) {
 811                         ret = -EFAULT;
 812                         goto free_counters;
 813                 }
 814
 815                 t = arpt_get_target_c(e);
 816                 if (copy_to_user(userptr + off + e->target_offset
 817                                  + offsetof(struct xt_entry_target,
 818                                             u.user.name),
 819                                  t->u.kernel.target->name,
 820                                  strlen(t->u.kernel.target->name)+1) != 0) {
 821                         ret = -EFAULT;
 822                         goto free_counters;
 823                 }
 824         }
 825
 826  free_counters:
 827         vfree(counters);
 828         return ret;
 829 }
 830
 831 #ifdef CONFIG_COMPAT
 832 static void compat_standard_from_user(void *dst, const void *src)
 833 {
 834         int v = *(compat_int_t *)src;
 835
 836         if (v > 0)
 837                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 838         memcpy(dst, &v, sizeof(v));
 839 }
 840
 841 static int compat_standard_to_user(void __user *dst, const void *src)
 842 {
 843         compat_int_t cv = *(int *)src;
 844
 845         if (cv > 0)
 846                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 847         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 848 }
 849
 850 static int compat_calc_entry(const struct arpt_entry *e,
 851                              const struct xt_table_info *info,
 852                              const void *base, struct xt_table_info *newinfo)
 853 {
 854         const struct xt_entry_target *t;
 855         unsigned int entry_offset;
 856         int off, i, ret;
 857
 858         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 859         entry_offset = (void *)e - base;
 860
 861         t = arpt_get_target_c(e);
 862         off += xt_compat_target_offset(t->u.kernel.target);
 863         newinfo->size -= off;
 864         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 865         if (ret)
 866                 return ret;
 867
 868         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 869                 if (info->hook_entry[i] &&
 870                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 871                         newinfo->hook_entry[i] -= off;
 872                 if (info->underflow[i] &&
 873                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 874                         newinfo->underflow[i] -= off;
 875         }
 876         return 0;
 877 }
 878
 879 static int compat_table_info(const struct xt_table_info *info,
 880                              struct xt_table_info *newinfo)
 881 {
 882         struct arpt_entry *iter;
 883         const void *loc_cpu_entry;
 884         int ret;
 885
 886         if (!newinfo || !info)
 887                 return -EINVAL;
 888
 889         /* we dont care about newinfo->entries */
 890         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 891         newinfo->initial_entries = 0;
 892         loc_cpu_entry = info->entries;
 893         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 894         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 895                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 896                 if (ret != 0)
 897                         return ret;
 898         }
 899         return 0;
 900 }
 901 #endif
 902
 903 static int get_info(struct net *net, void __user *user,
 904                     const int *len, int compat)
 905 {
 906         char name[XT_TABLE_MAXNAMELEN];
 907         struct xt_table *t;
 908         int ret;
 909
 910         if (*len != sizeof(struct arpt_getinfo)) {
 911                 duprintf("length %u != %Zu\n", *len,
 912                          sizeof(struct arpt_getinfo));
 913                 return -EINVAL;
 914         }
 915
 916         if (copy_from_user(name, user, sizeof(name)) != 0)
 917                 return -EFAULT;
 918
 919         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 920 #ifdef CONFIG_COMPAT
 921         if (compat)
 922                 xt_compat_lock(NFPROTO_ARP);
 923 #endif
 924         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 925                                     "arptable_%s", name);
 926         if (!IS_ERR_OR_NULL(t)) {
 927                 struct arpt_getinfo info;
 928                 const struct xt_table_info *private = t->private;
 929 #ifdef CONFIG_COMPAT
 930                 struct xt_table_info tmp;
 931
 932                 if (compat) {
 933                         ret = compat_table_info(private, &tmp);
 934                         xt_compat_flush_offsets(NFPROTO_ARP);
 935                         private = &tmp;
 936                 }
 937 #endif
 938                 memset(&info, 0, sizeof(info));
 939                 info.valid_hooks = t->valid_hooks;
 940                 memcpy(info.hook_entry, private->hook_entry,
 941                        sizeof(info.hook_entry));
 942                 memcpy(info.underflow, private->underflow,
 943                        sizeof(info.underflow));
 944                 info.num_entries = private->number;
 945                 info.size = private->size;
 946                 strcpy(info.name, name);
 947
 948                 if (copy_to_user(user, &info, *len) != 0)
 949                         ret = -EFAULT;
 950                 else
 951                         ret = 0;
 952                 xt_table_unlock(t);
 953                 module_put(t->me);
 954         } else
 955                 ret = t ? PTR_ERR(t) : -ENOENT;
 956 #ifdef CONFIG_COMPAT
 957         if (compat)
 958                 xt_compat_unlock(NFPROTO_ARP);
 959 #endif
 960         return ret;
 961 }
 962
 963 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 964                        const int *len)
 965 {
 966         int ret;
 967         struct arpt_get_entries get;
 968         struct xt_table *t;
 969
 970         if (*len < sizeof(get)) {
 971                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 972                 return -EINVAL;
 973         }
 974         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 975                 return -EFAULT;
 976         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 977                 duprintf("get_entries: %u != %Zu\n", *len,
 978                          sizeof(struct arpt_get_entries) + get.size);
 979                 return -EINVAL;
 980         }
 981         get.name[sizeof(get.name) - 1] = '\0';
 982
 983         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 984         if (!IS_ERR_OR_NULL(t)) {
 985                 const struct xt_table_info *private = t->private;
 986
 987                 duprintf("t->private->number = %u\n",
 988                          private->number);
 989                 if (get.size == private->size)
 990                         ret = copy_entries_to_user(private->size,
 991                                                    t, uptr->entrytable);
 992                 else {
 993                         duprintf("get_entries: I've got %u not %u!\n",
 994                                  private->size, get.size);
 995                         ret = -EAGAIN;
 996                 }
 997                 module_put(t->me);
 998                 xt_table_unlock(t);
 999         } else
1000                 ret = t ? PTR_ERR(t) : -ENOENT;
1001
1002         return ret;
1003 }
1004
1005 static int __do_replace(struct net *net, const char *name,
1006                         unsigned int valid_hooks,
1007                         struct xt_table_info *newinfo,
1008                         unsigned int num_counters,
1009                         void __user *counters_ptr)
1010 {
1011         int ret;
1012         struct xt_table *t;
1013         struct xt_table_info *oldinfo;
1014         struct xt_counters *counters;
1015         void *loc_cpu_old_entry;
1016         struct arpt_entry *iter;
1017
1018         ret = 0;
1019         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1020         if (!counters) {
1021                 ret = -ENOMEM;
1022                 goto out;
1023         }
1024
1025         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1026                                     "arptable_%s", name);
1027         if (IS_ERR_OR_NULL(t)) {
1028                 ret = t ? PTR_ERR(t) : -ENOENT;
1029                 goto free_newinfo_counters_untrans;
1030         }
1031
1032         /* You lied! */
1033         if (valid_hooks != t->valid_hooks) {
1034                 duprintf("Valid hook crap: %08X vs %08X\n",
1035                          valid_hooks, t->valid_hooks);
1036                 ret = -EINVAL;
1037                 goto put_module;
1038         }
1039
1040         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1041         if (!oldinfo)
1042                 goto put_module;
1043
1044         /* Update module usage count based on number of rules */
1045         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1046                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1047         if ((oldinfo->number > oldinfo->initial_entries) ||
1048             (newinfo->number <= oldinfo->initial_entries))
1049                 module_put(t->me);
1050         if ((oldinfo->number > oldinfo->initial_entries) &&
1051             (newinfo->number <= oldinfo->initial_entries))
1052                 module_put(t->me);
1053
1054         /* Get the old counters, and synchronize with replace */
1055         get_counters(oldinfo, counters);
1056
1057         /* Decrease module usage counts and free resource */
1058         loc_cpu_old_entry = oldinfo->entries;
1059         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1060                 cleanup_entry(iter);
1061
1062         xt_free_table_info(oldinfo);
1063         if (copy_to_user(counters_ptr, counters,
1064                          sizeof(struct xt_counters) * num_counters) != 0) {
1065                 /* Silent error, can't fail, new table is already in place */
1066                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1067         }
1068         vfree(counters);
1069         xt_table_unlock(t);
1070         return ret;
1071
1072  put_module:
1073         module_put(t->me);
1074         xt_table_unlock(t);
1075  free_newinfo_counters_untrans:
1076         vfree(counters);
1077  out:
1078         return ret;
1079 }
1080
1081 static int do_replace(struct net *net, const void __user *user,
1082                       unsigned int len)
1083 {
1084         int ret;
1085         struct arpt_replace tmp;
1086         struct xt_table_info *newinfo;
1087         void *loc_cpu_entry;
1088         struct arpt_entry *iter;
1089
1090         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1091                 return -EFAULT;
1092
1093         /* overflow check */
1094         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1095                 return -ENOMEM;
1096         if (tmp.num_counters == 0)
1097                 return -EINVAL;
1098
1099         tmp.name[sizeof(tmp.name)-1] = 0;
1100
1101         newinfo = xt_alloc_table_info(tmp.size);
1102         if (!newinfo)
1103                 return -ENOMEM;
1104
1105         loc_cpu_entry = newinfo->entries;
1106         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1107                            tmp.size) != 0) {
1108                 ret = -EFAULT;
1109                 goto free_newinfo;
1110         }
1111
1112         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1113         if (ret != 0)
1114                 goto free_newinfo;
1115
1116         duprintf("arp_tables: Translated table\n");
1117
1118         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1119                            tmp.num_counters, tmp.counters);
1120         if (ret)
1121                 goto free_newinfo_untrans;
1122         return 0;
1123
1124  free_newinfo_untrans:
1125         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1126                 cleanup_entry(iter);
1127  free_newinfo:
1128         xt_free_table_info(newinfo);
1129         return ret;
1130 }
1131
1132 static int do_add_counters(struct net *net, const void __user *user,
1133                            unsigned int len, int compat)
1134 {
1135         unsigned int i;
1136         struct xt_counters_info tmp;
1137         struct xt_counters *paddc;
1138         unsigned int num_counters;
1139         const char *name;
1140         int size;
1141         void *ptmp;
1142         struct xt_table *t;
1143         const struct xt_table_info *private;
1144         int ret = 0;
1145         struct arpt_entry *iter;
1146         unsigned int addend;
1147 #ifdef CONFIG_COMPAT
1148         struct compat_xt_counters_info compat_tmp;
1149
1150         if (compat) {
1151                 ptmp = &compat_tmp;
1152                 size = sizeof(struct compat_xt_counters_info);
1153         } else
1154 #endif
1155         {
1156                 ptmp = &tmp;
1157                 size = sizeof(struct xt_counters_info);
1158         }
1159
1160         if (copy_from_user(ptmp, user, size) != 0)
1161                 return -EFAULT;
1162
1163 #ifdef CONFIG_COMPAT
1164         if (compat) {
1165                 num_counters = compat_tmp.num_counters;
1166                 name = compat_tmp.name;
1167         } else
1168 #endif
1169         {
1170                 num_counters = tmp.num_counters;
1171                 name = tmp.name;
1172         }
1173
1174         if (len != size + num_counters * sizeof(struct xt_counters))
1175                 return -EINVAL;
1176
1177         paddc = vmalloc(len - size);
1178         if (!paddc)
1179                 return -ENOMEM;
1180
1181         if (copy_from_user(paddc, user + size, len - size) != 0) {
1182                 ret = -EFAULT;
1183                 goto free;
1184         }
1185
1186         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1187         if (IS_ERR_OR_NULL(t)) {
1188                 ret = t ? PTR_ERR(t) : -ENOENT;
1189                 goto free;
1190         }
1191
1192         local_bh_disable();
1193         private = t->private;
1194         if (private->number != num_counters) {
1195                 ret = -EINVAL;
1196                 goto unlock_up_free;
1197         }
1198
1199         i = 0;
1200
1201         addend = xt_write_recseq_begin();
1202         xt_entry_foreach(iter,  private->entries, private->size) {
1203                 struct xt_counters *tmp;
1204
1205                 tmp = xt_get_this_cpu_counter(&iter->counters);
1206                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1207                 ++i;
1208         }
1209         xt_write_recseq_end(addend);
1210  unlock_up_free:
1211         local_bh_enable();
1212         xt_table_unlock(t);
1213         module_put(t->me);
1214  free:
1215         vfree(paddc);
1216
1217         return ret;
1218 }
1219
1220 #ifdef CONFIG_COMPAT
1221 static inline void compat_release_entry(struct compat_arpt_entry *e)
1222 {
1223         struct xt_entry_target *t;
1224
1225         t = compat_arpt_get_target(e);
1226         module_put(t->u.kernel.target->me);
1227 }
1228
1229 static inline int
1230 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1231                                   struct xt_table_info *newinfo,
1232                                   unsigned int *size,
1233                                   const unsigned char *base,
1234                                   const unsigned char *limit,
1235                                   const unsigned int *hook_entries,
1236                                   const unsigned int *underflows,
1237                                   const char *name)
1238 {
1239         struct xt_entry_target *t;
1240         struct xt_target *target;
1241         unsigned int entry_offset;
1242         int ret, off, h;
1243
1244         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1245         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1246             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1247             (unsigned char *)e + e->next_offset > limit) {
1248                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1249                 return -EINVAL;
1250         }
1251
1252         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1253                              sizeof(struct compat_xt_entry_target)) {
1254                 duprintf("checking: element %p size %u\n",
1255                          e, e->next_offset);
1256                 return -EINVAL;
1257         }
1258
1259         /* For purposes of check_entry casting the compat entry is fine */
1260         ret = check_entry((struct arpt_entry *)e);
1261         if (ret)
1262                 return ret;
1263
1264         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1265         entry_offset = (void *)e - (void *)base;
1266
1267         t = compat_arpt_get_target(e);
1268         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1269                                         t->u.user.revision);
1270         if (IS_ERR(target)) {
1271                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1272                          t->u.user.name);
1273                 ret = PTR_ERR(target);
1274                 goto out;
1275         }
1276         t->u.kernel.target = target;
1277
1278         off += xt_compat_target_offset(target);
1279         *size += off;
1280         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1281         if (ret)
1282                 goto release_target;
1283
1284         /* Check hooks & underflows */
1285         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1286                 if ((unsigned char *)e - base == hook_entries[h])
1287                         newinfo->hook_entry[h] = hook_entries[h];
1288                 if ((unsigned char *)e - base == underflows[h])
1289                         newinfo->underflow[h] = underflows[h];
1290         }
1291
1292         /* Clear counters and comefrom */
1293         memset(&e->counters, 0, sizeof(e->counters));
1294         e->comefrom = 0;
1295         return 0;
1296
1297 release_target:
1298         module_put(t->u.kernel.target->me);
1299 out:
1300         return ret;
1301 }
1302
1303 static int
1304 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1305                             unsigned int *size, const char *name,
1306                             struct xt_table_info *newinfo, unsigned char *base)
1307 {
1308         struct xt_entry_target *t;
1309         struct xt_target *target;
1310         struct arpt_entry *de;
1311         unsigned int origsize;
1312         int ret, h;
1313
1314         ret = 0;
1315         origsize = *size;
1316         de = (struct arpt_entry *)*dstptr;
1317         memcpy(de, e, sizeof(struct arpt_entry));
1318         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1319
1320         *dstptr += sizeof(struct arpt_entry);
1321         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1322
1323         de->target_offset = e->target_offset - (origsize - *size);
1324         t = compat_arpt_get_target(e);
1325         target = t->u.kernel.target;
1326         xt_compat_target_from_user(t, dstptr, size);
1327
1328         de->next_offset = e->next_offset - (origsize - *size);
1329         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1330                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1331                         newinfo->hook_entry[h] -= origsize - *size;
1332                 if ((unsigned char *)de - base < newinfo->underflow[h])
1333                         newinfo->underflow[h] -= origsize - *size;
1334         }
1335         return ret;
1336 }
1337
1338 static int translate_compat_table(const char *name,
1339                                   unsigned int valid_hooks,
1340                                   struct xt_table_info **pinfo,
1341                                   void **pentry0,
1342                                   unsigned int total_size,
1343                                   unsigned int number,
1344                                   unsigned int *hook_entries,
1345                                   unsigned int *underflows)
1346 {
1347         unsigned int i, j;
1348         struct xt_table_info *newinfo, *info;
1349         void *pos, *entry0, *entry1;
1350         struct compat_arpt_entry *iter0;
1351         struct arpt_entry *iter1;
1352         unsigned int size;
1353         int ret = 0;
1354
1355         info = *pinfo;
1356         entry0 = *pentry0;
1357         size = total_size;
1358         info->number = number;
1359
1360         /* Init all hooks to impossible value. */
1361         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1362                 info->hook_entry[i] = 0xFFFFFFFF;
1363                 info->underflow[i] = 0xFFFFFFFF;
1364         }
1365
1366         duprintf("translate_compat_table: size %u\n", info->size);
1367         j = 0;
1368         xt_compat_lock(NFPROTO_ARP);
1369         xt_compat_init_offsets(NFPROTO_ARP, number);
1370         /* Walk through entries, checking offsets. */
1371         xt_entry_foreach(iter0, entry0, total_size) {
1372                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1373                                                         entry0,
1374                                                         entry0 + total_size,
1375                                                         hook_entries,
1376                                                         underflows,
1377                                                         name);
1378                 if (ret != 0)
1379                         goto out_unlock;
1380                 ++j;
1381         }
1382
1383         ret = -EINVAL;
1384         if (j != number) {
1385                 duprintf("translate_compat_table: %u not %u entries\n",
1386                          j, number);
1387                 goto out_unlock;
1388         }
1389
1390         /* Check hooks all assigned */
1391         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1392                 /* Only hooks which are valid */
1393                 if (!(valid_hooks & (1 << i)))
1394                         continue;
1395                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1396                         duprintf("Invalid hook entry %u %u\n",
1397                                  i, hook_entries[i]);
1398                         goto out_unlock;
1399                 }
1400                 if (info->underflow[i] == 0xFFFFFFFF) {
1401                         duprintf("Invalid underflow %u %u\n",
1402                                  i, underflows[i]);
1403                         goto out_unlock;
1404                 }
1405         }
1406
1407         ret = -ENOMEM;
1408         newinfo = xt_alloc_table_info(size);
1409         if (!newinfo)
1410                 goto out_unlock;
1411
1412         newinfo->number = number;
1413         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1414                 newinfo->hook_entry[i] = info->hook_entry[i];
1415                 newinfo->underflow[i] = info->underflow[i];
1416         }
1417         entry1 = newinfo->entries;
1418         pos = entry1;
1419         size = total_size;
1420         xt_entry_foreach(iter0, entry0, total_size) {
1421                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1422                                                   name, newinfo, entry1);
1423                 if (ret != 0)
1424                         break;
1425         }
1426         xt_compat_flush_offsets(NFPROTO_ARP);
1427         xt_compat_unlock(NFPROTO_ARP);
1428         if (ret)
1429                 goto free_newinfo;
1430
1431         ret = -ELOOP;
1432         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1433                 goto free_newinfo;
1434
1435         i = 0;
1436         xt_entry_foreach(iter1, entry1, newinfo->size) {
1437                 iter1->counters.pcnt = xt_percpu_counter_alloc();
1438                 if (IS_ERR_VALUE(iter1->counters.pcnt)) {
1439                         ret = -ENOMEM;
1440                         break;
1441                 }
1442
1443                 ret = check_target(iter1, name);
1444                 if (ret != 0) {
1445                         xt_percpu_counter_free(iter1->counters.pcnt);
1446                         break;
1447                 }
1448                 ++i;
1449                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1450                     XT_ERROR_TARGET) == 0)
1451                         ++newinfo->stacksize;
1452         }
1453         if (ret) {
1454                 /*
1455                  * The first i matches need cleanup_entry (calls ->destroy)
1456                  * because they had called ->check already. The other j-i
1457                  * entries need only release.
1458                  */
1459                 int skip = i;
1460                 j -= i;
1461                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1462                         if (skip-- > 0)
1463                                 continue;
1464                         if (j-- == 0)
1465                                 break;
1466                         compat_release_entry(iter0);
1467                 }
1468                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1469                         if (i-- == 0)
1470                                 break;
1471                         cleanup_entry(iter1);
1472                 }
1473                 xt_free_table_info(newinfo);
1474                 return ret;
1475         }
1476
1477         *pinfo = newinfo;
1478         *pentry0 = entry1;
1479         xt_free_table_info(info);
1480         return 0;
1481
1482 free_newinfo:
1483         xt_free_table_info(newinfo);
1484 out:
1485         xt_entry_foreach(iter0, entry0, total_size) {
1486                 if (j-- == 0)
1487                         break;
1488                 compat_release_entry(iter0);
1489         }
1490         return ret;
1491 out_unlock:
1492         xt_compat_flush_offsets(NFPROTO_ARP);
1493         xt_compat_unlock(NFPROTO_ARP);
1494         goto out;
1495 }
1496
1497 struct compat_arpt_replace {
1498         char                            name[XT_TABLE_MAXNAMELEN];
1499         u32                             valid_hooks;
1500         u32                             num_entries;
1501         u32                             size;
1502         u32                             hook_entry[NF_ARP_NUMHOOKS];
1503         u32                             underflow[NF_ARP_NUMHOOKS];
1504         u32                             num_counters;
1505         compat_uptr_t                   counters;
1506         struct compat_arpt_entry        entries[0];
1507 };
1508
1509 static int compat_do_replace(struct net *net, void __user *user,
1510                              unsigned int len)
1511 {
1512         int ret;
1513         struct compat_arpt_replace tmp;
1514         struct xt_table_info *newinfo;
1515         void *loc_cpu_entry;
1516         struct arpt_entry *iter;
1517
1518         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1519                 return -EFAULT;
1520
1521         /* overflow check */
1522         if (tmp.size >= INT_MAX / num_possible_cpus())
1523                 return -ENOMEM;
1524         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1525                 return -ENOMEM;
1526         if (tmp.num_counters == 0)
1527                 return -EINVAL;
1528
1529         tmp.name[sizeof(tmp.name)-1] = 0;
1530
1531         newinfo = xt_alloc_table_info(tmp.size);
1532         if (!newinfo)
1533                 return -ENOMEM;
1534
1535         loc_cpu_entry = newinfo->entries;
1536         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1537                 ret = -EFAULT;
1538                 goto free_newinfo;
1539         }
1540
1541         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1542                                      &newinfo, &loc_cpu_entry, tmp.size,
1543                                      tmp.num_entries, tmp.hook_entry,
1544                                      tmp.underflow);
1545         if (ret != 0)
1546                 goto free_newinfo;
1547
1548         duprintf("compat_do_replace: Translated table\n");
1549
1550         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1551                            tmp.num_counters, compat_ptr(tmp.counters));
1552         if (ret)
1553                 goto free_newinfo_untrans;
1554         return 0;
1555
1556  free_newinfo_untrans:
1557         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1558                 cleanup_entry(iter);
1559  free_newinfo:
1560         xt_free_table_info(newinfo);
1561         return ret;
1562 }
1563
1564 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1565                                   unsigned int len)
1566 {
1567         int ret;
1568
1569         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1570                 return -EPERM;
1571
1572         switch (cmd) {
1573         case ARPT_SO_SET_REPLACE:
1574                 ret = compat_do_replace(sock_net(sk), user, len);
1575                 break;
1576
1577         case ARPT_SO_SET_ADD_COUNTERS:
1578                 ret = do_add_counters(sock_net(sk), user, len, 1);
1579                 break;
1580
1581         default:
1582                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1583                 ret = -EINVAL;
1584         }
1585
1586         return ret;
1587 }
1588
1589 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1590                                      compat_uint_t *size,
1591                                      struct xt_counters *counters,
1592                                      unsigned int i)
1593 {
1594         struct xt_entry_target *t;
1595         struct compat_arpt_entry __user *ce;
1596         u_int16_t target_offset, next_offset;
1597         compat_uint_t origsize;
1598         int ret;
1599
1600         origsize = *size;
1601         ce = (struct compat_arpt_entry __user *)*dstptr;
1602         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1603             copy_to_user(&ce->counters, &counters[i],
1604             sizeof(counters[i])) != 0)
1605                 return -EFAULT;
1606
1607         *dstptr += sizeof(struct compat_arpt_entry);
1608         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1609
1610         target_offset = e->target_offset - (origsize - *size);
1611
1612         t = arpt_get_target(e);
1613         ret = xt_compat_target_to_user(t, dstptr, size);
1614         if (ret)
1615                 return ret;
1616         next_offset = e->next_offset - (origsize - *size);
1617         if (put_user(target_offset, &ce->target_offset) != 0 ||
1618             put_user(next_offset, &ce->next_offset) != 0)
1619                 return -EFAULT;
1620         return 0;
1621 }
1622
1623 static int compat_copy_entries_to_user(unsigned int total_size,
1624                                        struct xt_table *table,
1625                                        void __user *userptr)
1626 {
1627         struct xt_counters *counters;
1628         const struct xt_table_info *private = table->private;
1629         void __user *pos;
1630         unsigned int size;
1631         int ret = 0;
1632         unsigned int i = 0;
1633         struct arpt_entry *iter;
1634
1635         counters = alloc_counters(table);
1636         if (IS_ERR(counters))
1637                 return PTR_ERR(counters);
1638
1639         pos = userptr;
1640         size = total_size;
1641         xt_entry_foreach(iter, private->entries, total_size) {
1642                 ret = compat_copy_entry_to_user(iter, &pos,
1643                                                 &size, counters, i++);
1644                 if (ret != 0)
1645                         break;
1646         }
1647         vfree(counters);
1648         return ret;
1649 }
1650
1651 struct compat_arpt_get_entries {
1652         char name[XT_TABLE_MAXNAMELEN];
1653         compat_uint_t size;
1654         struct compat_arpt_entry entrytable[0];
1655 };
1656
1657 static int compat_get_entries(struct net *net,
1658                               struct compat_arpt_get_entries __user *uptr,
1659                               int *len)
1660 {
1661         int ret;
1662         struct compat_arpt_get_entries get;
1663         struct xt_table *t;
1664
1665         if (*len < sizeof(get)) {
1666                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1667                 return -EINVAL;
1668         }
1669         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1670                 return -EFAULT;
1671         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1672                 duprintf("compat_get_entries: %u != %zu\n",
1673                          *len, sizeof(get) + get.size);
1674                 return -EINVAL;
1675         }
1676         get.name[sizeof(get.name) - 1] = '\0';
1677
1678         xt_compat_lock(NFPROTO_ARP);
1679         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1680         if (!IS_ERR_OR_NULL(t)) {
1681                 const struct xt_table_info *private = t->private;
1682                 struct xt_table_info info;
1683
1684                 duprintf("t->private->number = %u\n", private->number);
1685                 ret = compat_table_info(private, &info);
1686                 if (!ret && get.size == info.size) {
1687                         ret = compat_copy_entries_to_user(private->size,
1688                                                           t, uptr->entrytable);
1689                 } else if (!ret) {
1690                         duprintf("compat_get_entries: I've got %u not %u!\n",
1691                                  private->size, get.size);
1692                         ret = -EAGAIN;
1693                 }
1694                 xt_compat_flush_offsets(NFPROTO_ARP);
1695                 module_put(t->me);
1696                 xt_table_unlock(t);
1697         } else
1698                 ret = t ? PTR_ERR(t) : -ENOENT;
1699
1700         xt_compat_unlock(NFPROTO_ARP);
1701         return ret;
1702 }
1703
1704 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1705
1706 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1707                                   int *len)
1708 {
1709         int ret;
1710
1711         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1712                 return -EPERM;
1713
1714         switch (cmd) {
1715         case ARPT_SO_GET_INFO:
1716                 ret = get_info(sock_net(sk), user, len, 1);
1717                 break;
1718         case ARPT_SO_GET_ENTRIES:
1719                 ret = compat_get_entries(sock_net(sk), user, len);
1720                 break;
1721         default:
1722                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1723         }
1724         return ret;
1725 }
1726 #endif
1727
1728 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1729 {
1730         int ret;
1731
1732         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1733                 return -EPERM;
1734
1735         switch (cmd) {
1736         case ARPT_SO_SET_REPLACE:
1737                 ret = do_replace(sock_net(sk), user, len);
1738                 break;
1739
1740         case ARPT_SO_SET_ADD_COUNTERS:
1741                 ret = do_add_counters(sock_net(sk), user, len, 0);
1742                 break;
1743
1744         default:
1745                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1746                 ret = -EINVAL;
1747         }
1748
1749         return ret;
1750 }
1751
1752 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1753 {
1754         int ret;
1755
1756         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1757                 return -EPERM;
1758
1759         switch (cmd) {
1760         case ARPT_SO_GET_INFO:
1761                 ret = get_info(sock_net(sk), user, len, 0);
1762                 break;
1763
1764         case ARPT_SO_GET_ENTRIES:
1765                 ret = get_entries(sock_net(sk), user, len);
1766                 break;
1767
1768         case ARPT_SO_GET_REVISION_TARGET: {
1769                 struct xt_get_revision rev;
1770
1771                 if (*len != sizeof(rev)) {
1772                         ret = -EINVAL;
1773                         break;
1774                 }
1775                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1776                         ret = -EFAULT;
1777                         break;
1778                 }
1779                 rev.name[sizeof(rev.name)-1] = 0;
1780
1781                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1782                                                          rev.revision, 1, &ret),
1783                                         "arpt_%s", rev.name);
1784                 break;
1785         }
1786
1787         default:
1788                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1789                 ret = -EINVAL;
1790         }
1791
1792         return ret;
1793 }
1794
1795 static void __arpt_unregister_table(struct xt_table *table)
1796 {
1797         struct xt_table_info *private;
1798         void *loc_cpu_entry;
1799         struct module *table_owner = table->me;
1800         struct arpt_entry *iter;
1801
1802         private = xt_unregister_table(table);
1803
1804         /* Decrease module usage counts and free resources */
1805         loc_cpu_entry = private->entries;
1806         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1807                 cleanup_entry(iter);
1808         if (private->number > private->initial_entries)
1809                 module_put(table_owner);
1810         xt_free_table_info(private);
1811 }
1812
1813 int arpt_register_table(struct net *net,
1814                         const struct xt_table *table,
1815                         const struct arpt_replace *repl,
1816                         const struct nf_hook_ops *ops,
1817                         struct xt_table **res)
1818 {
1819         int ret;
1820         struct xt_table_info *newinfo;
1821         struct xt_table_info bootstrap = {0};
1822         void *loc_cpu_entry;
1823         struct xt_table *new_table;
1824
1825         newinfo = xt_alloc_table_info(repl->size);
1826         if (!newinfo)
1827                 return -ENOMEM;
1828
1829         loc_cpu_entry = newinfo->entries;
1830         memcpy(loc_cpu_entry, repl->entries, repl->size);
1831
1832         ret = translate_table(newinfo, loc_cpu_entry, repl);
1833         duprintf("arpt_register_table: translate table gives %d\n", ret);
1834         if (ret != 0)
1835                 goto out_free;
1836
1837         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1838         if (IS_ERR(new_table)) {
1839                 ret = PTR_ERR(new_table);
1840                 goto out_free;
1841         }
1842
1843         /* set res now, will see skbs right after nf_register_net_hooks */
1844         WRITE_ONCE(*res, new_table);
1845
1846         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1847         if (ret != 0) {
1848                 __arpt_unregister_table(new_table);
1849                 *res = NULL;
1850         }
1851
1852         return ret;
1853
1854 out_free:
1855         xt_free_table_info(newinfo);
1856         return ret;
1857 }
1858
1859 void arpt_unregister_table(struct net *net, struct xt_table *table,
1860                            const struct nf_hook_ops *ops)
1861 {
1862         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1863         __arpt_unregister_table(table);
1864 }
1865
1866 /* The built-in targets: standard (NULL) and error. */
1867 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1868         {
1869                 .name             = XT_STANDARD_TARGET,
1870                 .targetsize       = sizeof(int),
1871                 .family           = NFPROTO_ARP,
1872 #ifdef CONFIG_COMPAT
1873                 .compatsize       = sizeof(compat_int_t),
1874                 .compat_from_user = compat_standard_from_user,
1875                 .compat_to_user   = compat_standard_to_user,
1876 #endif
1877         },
1878         {
1879                 .name             = XT_ERROR_TARGET,
1880                 .target           = arpt_error,
1881                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1882                 .family           = NFPROTO_ARP,
1883         },
1884 };
1885
1886 static struct nf_sockopt_ops arpt_sockopts = {
1887         .pf             = PF_INET,
1888         .set_optmin     = ARPT_BASE_CTL,
1889         .set_optmax     = ARPT_SO_SET_MAX+1,
1890         .set            = do_arpt_set_ctl,
1891 #ifdef CONFIG_COMPAT
1892         .compat_set     = compat_do_arpt_set_ctl,
1893 #endif
1894         .get_optmin     = ARPT_BASE_CTL,
1895         .get_optmax     = ARPT_SO_GET_MAX+1,
1896         .get            = do_arpt_get_ctl,
1897 #ifdef CONFIG_COMPAT
1898         .compat_get     = compat_do_arpt_get_ctl,
1899 #endif
1900         .owner          = THIS_MODULE,
1901 };
1902
1903 static int __net_init arp_tables_net_init(struct net *net)
1904 {
1905         return xt_proto_init(net, NFPROTO_ARP);
1906 }
1907
1908 static void __net_exit arp_tables_net_exit(struct net *net)
1909 {
1910         xt_proto_fini(net, NFPROTO_ARP);
1911 }
1912
1913 static struct pernet_operations arp_tables_net_ops = {
1914         .init = arp_tables_net_init,
1915         .exit = arp_tables_net_exit,
1916 };
1917
1918 static int __init arp_tables_init(void)
1919 {
1920         int ret;
1921
1922         ret = register_pernet_subsys(&arp_tables_net_ops);
1923         if (ret < 0)
1924                 goto err1;
1925
1926         /* No one else will be downing sem now, so we won't sleep */
1927         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1928         if (ret < 0)
1929                 goto err2;
1930
1931         /* Register setsockopt */
1932         ret = nf_register_sockopt(&arpt_sockopts);
1933         if (ret < 0)
1934                 goto err4;
1935
1936         pr_info("arp_tables: (C) 2002 David S. Miller\n");
1937         return 0;
1938
1939 err4:
1940         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1941 err2:
1942         unregister_pernet_subsys(&arp_tables_net_ops);
1943 err1:
1944         return ret;
1945 }
1946
1947 static void __exit arp_tables_fini(void)
1948 {
1949         nf_unregister_sockopt(&arpt_sockopts);
1950         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1951         unregister_pernet_subsys(&arp_tables_net_ops);
1952 }
1953
1954 EXPORT_SYMBOL(arpt_register_table);
1955 EXPORT_SYMBOL(arpt_unregister_table);
1956 EXPORT_SYMBOL(arpt_do_table);
1957
1958 module_init(arp_tables_init);
1959 module_exit(arp_tables_fini);