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  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/capability.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/kmod.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/mutex.h>
  23 #include <linux/err.h>
  24 #include <net/compat.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter_arp/arp_tables.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  33 MODULE_DESCRIPTION("arptables core");
  34
  35 /*#define DEBUG_ARP_TABLES*/
  36 /*#define DEBUG_ARP_TABLES_USER*/
  37
  38 #ifdef DEBUG_ARP_TABLES
  39 #define dprintf(format, args...)  printk(format , ## args)
  40 #else
  41 #define dprintf(format, args...)
  42 #endif
  43
  44 #ifdef DEBUG_ARP_TABLES_USER
  45 #define duprintf(format, args...) printk(format , ## args)
  46 #else
  47 #define duprintf(format, args...)
  48 #endif
  49
  50 #ifdef CONFIG_NETFILTER_DEBUG
  51 #define ARP_NF_ASSERT(x)                                        \
  52 do {                                                            \
  53         if (!(x))                                               \
  54                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  55                        __func__, __FILE__, __LINE__);   \
  56 } while(0)
  57 #else
  58 #define ARP_NF_ASSERT(x)
  59 #endif
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       const char *hdr_addr, int len)
  63 {
  64         int i, ret;
  65
  66         if (len > ARPT_DEV_ADDR_LEN_MAX)
  67                 len = ARPT_DEV_ADDR_LEN_MAX;
  68
  69         ret = 0;
  70         for (i = 0; i < len; i++)
  71                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  72
  73         return (ret != 0);
  74 }
  75
  76 /* Returns whether packet matches rule or not. */
  77 static inline int arp_packet_match(const struct arphdr *arphdr,
  78                                    struct net_device *dev,
  79                                    const char *indev,
  80                                    const char *outdev,
  81                                    const struct arpt_arp *arpinfo)
  82 {
  83         const char *arpptr = (char *)(arphdr + 1);
  84         const char *src_devaddr, *tgt_devaddr;
  85         __be32 src_ipaddr, tgt_ipaddr;
  86         int i, ret;
  87
  88 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
  89
  90         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
  91                   ARPT_INV_ARPOP)) {
  92                 dprintf("ARP operation field mismatch.\n");
  93                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
  94                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
  95                 return 0;
  96         }
  97
  98         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
  99                   ARPT_INV_ARPHRD)) {
 100                 dprintf("ARP hardware address format mismatch.\n");
 101                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 102                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 103                 return 0;
 104         }
 105
 106         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 107                   ARPT_INV_ARPPRO)) {
 108                 dprintf("ARP protocol address format mismatch.\n");
 109                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 110                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 111                 return 0;
 112         }
 113
 114         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 115                   ARPT_INV_ARPHLN)) {
 116                 dprintf("ARP hardware address length mismatch.\n");
 117                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 118                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 119                 return 0;
 120         }
 121
 122         src_devaddr = arpptr;
 123         arpptr += dev->addr_len;
 124         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 125         arpptr += sizeof(u32);
 126         tgt_devaddr = arpptr;
 127         arpptr += dev->addr_len;
 128         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 129
 130         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 131                   ARPT_INV_SRCDEVADDR) ||
 132             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 133                   ARPT_INV_TGTDEVADDR)) {
 134                 dprintf("Source or target device address mismatch.\n");
 135
 136                 return 0;
 137         }
 138
 139         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 140                   ARPT_INV_SRCIP) ||
 141             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 142                   ARPT_INV_TGTIP)) {
 143                 dprintf("Source or target IP address mismatch.\n");
 144
 145                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 146                         &src_ipaddr,
 147                         &arpinfo->smsk.s_addr,
 148                         &arpinfo->src.s_addr,
 149                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 150                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 151                         &tgt_ipaddr,
 152                         &arpinfo->tmsk.s_addr,
 153                         &arpinfo->tgt.s_addr,
 154                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 155                 return 0;
 156         }
 157
 158         /* Look for ifname matches.  */
 159         for (i = 0, ret = 0; i < IFNAMSIZ; i++) {
 160                 ret |= (indev[i] ^ arpinfo->iniface[i])
 161                         & arpinfo->iniface_mask[i];
 162         }
 163
 164         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 165                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 166                         indev, arpinfo->iniface,
 167                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 168                 return 0;
 169         }
 170
 171         for (i = 0, ret = 0; i < IFNAMSIZ; i++) {
 172                 ret |= (outdev[i] ^ arpinfo->outiface[i])
 173                         & arpinfo->outiface_mask[i];
 174         }
 175
 176         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 177                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 178                         outdev, arpinfo->outiface,
 179                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 180                 return 0;
 181         }
 182
 183         return 1;
 184 #undef FWINV
 185 }
 186
 187 static inline int arp_checkentry(const struct arpt_arp *arp)
 188 {
 189         if (arp->flags & ~ARPT_F_MASK) {
 190                 duprintf("Unknown flag bits set: %08X\n",
 191                          arp->flags & ~ARPT_F_MASK);
 192                 return 0;
 193         }
 194         if (arp->invflags & ~ARPT_INV_MASK) {
 195                 duprintf("Unknown invflag bits set: %08X\n",
 196                          arp->invflags & ~ARPT_INV_MASK);
 197                 return 0;
 198         }
 199
 200         return 1;
 201 }
 202
 203 static unsigned int
 204 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 205 {
 206         if (net_ratelimit())
 207                 printk("arp_tables: error: '%s'\n",
 208                        (const char *)par->targinfo);
 209
 210         return NF_DROP;
 211 }
 212
 213 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 214 {
 215         return (struct arpt_entry *)(base + offset);
 216 }
 217
 218 unsigned int arpt_do_table(struct sk_buff *skb,
 219                            unsigned int hook,
 220                            const struct net_device *in,
 221                            const struct net_device *out,
 222                            struct xt_table *table)
 223 {
 224         static const char nulldevname[IFNAMSIZ];
 225         unsigned int verdict = NF_DROP;
 226         const struct arphdr *arp;
 227         bool hotdrop = false;
 228         struct arpt_entry *e, *back;
 229         const char *indev, *outdev;
 230         void *table_base;
 231         const struct xt_table_info *private;
 232         struct xt_target_param tgpar;
 233
 234         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 235                 return NF_DROP;
 236
 237         indev = in ? in->name : nulldevname;
 238         outdev = out ? out->name : nulldevname;
 239
 240         read_lock_bh(&table->lock);
 241         private = table->private;
 242         table_base = (void *)private->entries[smp_processor_id()];
 243         e = get_entry(table_base, private->hook_entry[hook]);
 244         back = get_entry(table_base, private->underflow[hook]);
 245
 246         tgpar.in      = in;
 247         tgpar.out     = out;
 248         tgpar.hooknum = hook;
 249         tgpar.family  = NFPROTO_ARP;
 250
 251         arp = arp_hdr(skb);
 252         do {
 253                 if (arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 254                         struct arpt_entry_target *t;
 255                         int hdr_len;
 256
 257                         hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 258                                 (2 * skb->dev->addr_len);
 259                         ADD_COUNTER(e->counters, hdr_len, 1);
 260
 261                         t = arpt_get_target(e);
 262
 263                         /* Standard target? */
 264                         if (!t->u.kernel.target->target) {
 265                                 int v;
 266
 267                                 v = ((struct arpt_standard_target *)t)->verdict;
 268                                 if (v < 0) {
 269                                         /* Pop from stack? */
 270                                         if (v != ARPT_RETURN) {
 271                                                 verdict = (unsigned)(-v) - 1;
 272                                                 break;
 273                                         }
 274                                         e = back;
 275                                         back = get_entry(table_base,
 276                                                          back->comefrom);
 277                                         continue;
 278                                 }
 279                                 if (table_base + v
 280                                     != (void *)e + e->next_offset) {
 281                                         /* Save old back ptr in next entry */
 282                                         struct arpt_entry *next
 283                                                 = (void *)e + e->next_offset;
 284                                         next->comefrom =
 285                                                 (void *)back - table_base;
 286
 287                                         /* set back pointer to next entry */
 288                                         back = next;
 289                                 }
 290
 291                                 e = get_entry(table_base, v);
 292                         } else {
 293                                 /* Targets which reenter must return
 294                                  * abs. verdicts
 295                                  */
 296                                 tgpar.target   = t->u.kernel.target;
 297                                 tgpar.targinfo = t->data;
 298                                 verdict = t->u.kernel.target->target(skb,
 299                                                                      &tgpar);
 300
 301                                 /* Target might have changed stuff. */
 302                                 arp = arp_hdr(skb);
 303
 304                                 if (verdict == ARPT_CONTINUE)
 305                                         e = (void *)e + e->next_offset;
 306                                 else
 307                                         /* Verdict */
 308                                         break;
 309                         }
 310                 } else {
 311                         e = (void *)e + e->next_offset;
 312                 }
 313         } while (!hotdrop);
 314         read_unlock_bh(&table->lock);
 315
 316         if (hotdrop)
 317                 return NF_DROP;
 318         else
 319                 return verdict;
 320 }
 321
 322 /* All zeroes == unconditional rule. */
 323 static inline int unconditional(const struct arpt_arp *arp)
 324 {
 325         unsigned int i;
 326
 327         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 328                 if (((__u32 *)arp)[i])
 329                         return 0;
 330
 331         return 1;
 332 }
 333
 334 /* Figures out from what hook each rule can be called: returns 0 if
 335  * there are loops.  Puts hook bitmask in comefrom.
 336  */
 337 static int mark_source_chains(struct xt_table_info *newinfo,
 338                               unsigned int valid_hooks, void *entry0)
 339 {
 340         unsigned int hook;
 341
 342         /* No recursion; use packet counter to save back ptrs (reset
 343          * to 0 as we leave), and comefrom to save source hook bitmask.
 344          */
 345         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 346                 unsigned int pos = newinfo->hook_entry[hook];
 347                 struct arpt_entry *e
 348                         = (struct arpt_entry *)(entry0 + pos);
 349
 350                 if (!(valid_hooks & (1 << hook)))
 351                         continue;
 352
 353                 /* Set initial back pointer. */
 354                 e->counters.pcnt = pos;
 355
 356                 for (;;) {
 357                         const struct arpt_standard_target *t
 358                                 = (void *)arpt_get_target(e);
 359                         int visited = e->comefrom & (1 << hook);
 360
 361                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 362                                 printk("arptables: loop hook %u pos %u %08X.\n",
 363                                        hook, pos, e->comefrom);
 364                                 return 0;
 365                         }
 366                         e->comefrom
 367                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 368
 369                         /* Unconditional return/END. */
 370                         if ((e->target_offset == sizeof(struct arpt_entry)
 371                             && (strcmp(t->target.u.user.name,
 372                                        ARPT_STANDARD_TARGET) == 0)
 373                             && t->verdict < 0
 374                             && unconditional(&e->arp)) || visited) {
 375                                 unsigned int oldpos, size;
 376
 377                                 if (t->verdict < -NF_MAX_VERDICT - 1) {
 378                                         duprintf("mark_source_chains: bad "
 379                                                 "negative verdict (%i)\n",
 380                                                                 t->verdict);
 381                                         return 0;
 382                                 }
 383
 384                                 /* Return: backtrack through the last
 385                                  * big jump.
 386                                  */
 387                                 do {
 388                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 389                                         oldpos = pos;
 390                                         pos = e->counters.pcnt;
 391                                         e->counters.pcnt = 0;
 392
 393                                         /* We're at the start. */
 394                                         if (pos == oldpos)
 395                                                 goto next;
 396
 397                                         e = (struct arpt_entry *)
 398                                                 (entry0 + pos);
 399                                 } while (oldpos == pos + e->next_offset);
 400
 401                                 /* Move along one */
 402                                 size = e->next_offset;
 403                                 e = (struct arpt_entry *)
 404                                         (entry0 + pos + size);
 405                                 e->counters.pcnt = pos;
 406                                 pos += size;
 407                         } else {
 408                                 int newpos = t->verdict;
 409
 410                                 if (strcmp(t->target.u.user.name,
 411                                            ARPT_STANDARD_TARGET) == 0
 412                                     && newpos >= 0) {
 413                                         if (newpos > newinfo->size -
 414                                                 sizeof(struct arpt_entry)) {
 415                                                 duprintf("mark_source_chains: "
 416                                                         "bad verdict (%i)\n",
 417                                                                 newpos);
 418                                                 return 0;
 419                                         }
 420
 421                                         /* This a jump; chase it. */
 422                                         duprintf("Jump rule %u -> %u\n",
 423                                                  pos, newpos);
 424                                 } else {
 425                                         /* ... this is a fallthru */
 426                                         newpos = pos + e->next_offset;
 427                                 }
 428                                 e = (struct arpt_entry *)
 429                                         (entry0 + newpos);
 430                                 e->counters.pcnt = pos;
 431                                 pos = newpos;
 432                         }
 433                 }
 434                 next:
 435                 duprintf("Finished chain %u\n", hook);
 436         }
 437         return 1;
 438 }
 439
 440 static inline int check_entry(struct arpt_entry *e, const char *name)
 441 {
 442         const struct arpt_entry_target *t;
 443
 444         if (!arp_checkentry(&e->arp)) {
 445                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 446                 return -EINVAL;
 447         }
 448
 449         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 450                 return -EINVAL;
 451
 452         t = arpt_get_target(e);
 453         if (e->target_offset + t->u.target_size > e->next_offset)
 454                 return -EINVAL;
 455
 456         return 0;
 457 }
 458
 459 static inline int check_target(struct arpt_entry *e, const char *name)
 460 {
 461         struct arpt_entry_target *t = arpt_get_target(e);
 462         int ret;
 463         struct xt_tgchk_param par = {
 464                 .table     = name,
 465                 .entryinfo = e,
 466                 .target    = t->u.kernel.target,
 467                 .targinfo  = t->data,
 468                 .hook_mask = e->comefrom,
 469                 .family    = NFPROTO_ARP,
 470         };
 471
 472         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 473         if (ret < 0) {
 474                 duprintf("arp_tables: check failed for `%s'.\n",
 475                          t->u.kernel.target->name);
 476                 return ret;
 477         }
 478         return 0;
 479 }
 480
 481 static inline int
 482 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 483                  unsigned int *i)
 484 {
 485         struct arpt_entry_target *t;
 486         struct xt_target *target;
 487         int ret;
 488
 489         ret = check_entry(e, name);
 490         if (ret)
 491                 return ret;
 492
 493         t = arpt_get_target(e);
 494         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 495                                                         t->u.user.name,
 496                                                         t->u.user.revision),
 497                                          "arpt_%s", t->u.user.name);
 498         if (IS_ERR(target) || !target) {
 499                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 500                 ret = target ? PTR_ERR(target) : -ENOENT;
 501                 goto out;
 502         }
 503         t->u.kernel.target = target;
 504
 505         ret = check_target(e, name);
 506         if (ret)
 507                 goto err;
 508
 509         (*i)++;
 510         return 0;
 511 err:
 512         module_put(t->u.kernel.target->me);
 513 out:
 514         return ret;
 515 }
 516
 517 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 518                                              struct xt_table_info *newinfo,
 519                                              unsigned char *base,
 520                                              unsigned char *limit,
 521                                              const unsigned int *hook_entries,
 522                                              const unsigned int *underflows,
 523                                              unsigned int *i)
 524 {
 525         unsigned int h;
 526
 527         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 528             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 529                 duprintf("Bad offset %p\n", e);
 530                 return -EINVAL;
 531         }
 532
 533         if (e->next_offset
 534             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 535                 duprintf("checking: element %p size %u\n",
 536                          e, e->next_offset);
 537                 return -EINVAL;
 538         }
 539
 540         /* Check hooks & underflows */
 541         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 542                 if ((unsigned char *)e - base == hook_entries[h])
 543                         newinfo->hook_entry[h] = hook_entries[h];
 544                 if ((unsigned char *)e - base == underflows[h])
 545                         newinfo->underflow[h] = underflows[h];
 546         }
 547
 548         /* FIXME: underflows must be unconditional, standard verdicts
 549            < 0 (not ARPT_RETURN). --RR */
 550
 551         /* Clear counters and comefrom */
 552         e->counters = ((struct xt_counters) { 0, 0 });
 553         e->comefrom = 0;
 554
 555         (*i)++;
 556         return 0;
 557 }
 558
 559 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 560 {
 561         struct xt_tgdtor_param par;
 562         struct arpt_entry_target *t;
 563
 564         if (i && (*i)-- == 0)
 565                 return 1;
 566
 567         t = arpt_get_target(e);
 568         par.target   = t->u.kernel.target;
 569         par.targinfo = t->data;
 570         par.family   = NFPROTO_ARP;
 571         if (par.target->destroy != NULL)
 572                 par.target->destroy(&par);
 573         module_put(par.target->me);
 574         return 0;
 575 }
 576
 577 /* Checks and translates the user-supplied table segment (held in
 578  * newinfo).
 579  */
 580 static int translate_table(const char *name,
 581                            unsigned int valid_hooks,
 582                            struct xt_table_info *newinfo,
 583                            void *entry0,
 584                            unsigned int size,
 585                            unsigned int number,
 586                            const unsigned int *hook_entries,
 587                            const unsigned int *underflows)
 588 {
 589         unsigned int i;
 590         int ret;
 591
 592         newinfo->size = size;
 593         newinfo->number = number;
 594
 595         /* Init all hooks to impossible value. */
 596         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 597                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 598                 newinfo->underflow[i] = 0xFFFFFFFF;
 599         }
 600
 601         duprintf("translate_table: size %u\n", newinfo->size);
 602         i = 0;
 603
 604         /* Walk through entries, checking offsets. */
 605         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 606                                  check_entry_size_and_hooks,
 607                                  newinfo,
 608                                  entry0,
 609                                  entry0 + size,
 610                                  hook_entries, underflows, &i);
 611         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 612         if (ret != 0)
 613                 return ret;
 614
 615         if (i != number) {
 616                 duprintf("translate_table: %u not %u entries\n",
 617                          i, number);
 618                 return -EINVAL;
 619         }
 620
 621         /* Check hooks all assigned */
 622         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 623                 /* Only hooks which are valid */
 624                 if (!(valid_hooks & (1 << i)))
 625                         continue;
 626                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 627                         duprintf("Invalid hook entry %u %u\n",
 628                                  i, hook_entries[i]);
 629                         return -EINVAL;
 630                 }
 631                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 632                         duprintf("Invalid underflow %u %u\n",
 633                                  i, underflows[i]);
 634                         return -EINVAL;
 635                 }
 636         }
 637
 638         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 639                 duprintf("Looping hook\n");
 640                 return -ELOOP;
 641         }
 642
 643         /* Finally, each sanity check must pass */
 644         i = 0;
 645         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 646                                  find_check_entry, name, size, &i);
 647
 648         if (ret != 0) {
 649                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 650                                 cleanup_entry, &i);
 651                 return ret;
 652         }
 653
 654         /* And one copy for every other CPU */
 655         for_each_possible_cpu(i) {
 656                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 657                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 658         }
 659
 660         return ret;
 661 }
 662
 663 /* Gets counters. */
 664 static inline int add_entry_to_counter(const struct arpt_entry *e,
 665                                        struct xt_counters total[],
 666                                        unsigned int *i)
 667 {
 668         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 669
 670         (*i)++;
 671         return 0;
 672 }
 673
 674 static inline int set_entry_to_counter(const struct arpt_entry *e,
 675                                        struct xt_counters total[],
 676                                        unsigned int *i)
 677 {
 678         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 679
 680         (*i)++;
 681         return 0;
 682 }
 683
 684 static void get_counters(const struct xt_table_info *t,
 685                          struct xt_counters counters[])
 686 {
 687         unsigned int cpu;
 688         unsigned int i;
 689         unsigned int curcpu;
 690
 691         /* Instead of clearing (by a previous call to memset())
 692          * the counters and using adds, we set the counters
 693          * with data used by 'current' CPU
 694          * We dont care about preemption here.
 695          */
 696         curcpu = raw_smp_processor_id();
 697
 698         i = 0;
 699         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 700                            t->size,
 701                            set_entry_to_counter,
 702                            counters,
 703                            &i);
 704
 705         for_each_possible_cpu(cpu) {
 706                 if (cpu == curcpu)
 707                         continue;
 708                 i = 0;
 709                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 710                                    t->size,
 711                                    add_entry_to_counter,
 712                                    counters,
 713                                    &i);
 714         }
 715 }
 716
 717 static inline struct xt_counters *alloc_counters(struct xt_table *table)
 718 {
 719         unsigned int countersize;
 720         struct xt_counters *counters;
 721         const struct xt_table_info *private = table->private;
 722
 723         /* We need atomic snapshot of counters: rest doesn't change
 724          * (other than comefrom, which userspace doesn't care
 725          * about).
 726          */
 727         countersize = sizeof(struct xt_counters) * private->number;
 728         counters = vmalloc_node(countersize, numa_node_id());
 729
 730         if (counters == NULL)
 731                 return ERR_PTR(-ENOMEM);
 732
 733         /* First, sum counters... */
 734         write_lock_bh(&table->lock);
 735         get_counters(private, counters);
 736         write_unlock_bh(&table->lock);
 737
 738         return counters;
 739 }
 740
 741 static int copy_entries_to_user(unsigned int total_size,
 742                                 struct xt_table *table,
 743                                 void __user *userptr)
 744 {
 745         unsigned int off, num;
 746         struct arpt_entry *e;
 747         struct xt_counters *counters;
 748         struct xt_table_info *private = table->private;
 749         int ret = 0;
 750         void *loc_cpu_entry;
 751
 752         counters = alloc_counters(table);
 753         if (IS_ERR(counters))
 754                 return PTR_ERR(counters);
 755
 756         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 757         /* ... then copy entire thing ... */
 758         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 759                 ret = -EFAULT;
 760                 goto free_counters;
 761         }
 762
 763         /* FIXME: use iterator macros --RR */
 764         /* ... then go back and fix counters and names */
 765         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 766                 struct arpt_entry_target *t;
 767
 768                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 769                 if (copy_to_user(userptr + off
 770                                  + offsetof(struct arpt_entry, counters),
 771                                  &counters[num],
 772                                  sizeof(counters[num])) != 0) {
 773                         ret = -EFAULT;
 774                         goto free_counters;
 775                 }
 776
 777                 t = arpt_get_target(e);
 778                 if (copy_to_user(userptr + off + e->target_offset
 779                                  + offsetof(struct arpt_entry_target,
 780                                             u.user.name),
 781                                  t->u.kernel.target->name,
 782                                  strlen(t->u.kernel.target->name)+1) != 0) {
 783                         ret = -EFAULT;
 784                         goto free_counters;
 785                 }
 786         }
 787
 788  free_counters:
 789         vfree(counters);
 790         return ret;
 791 }
 792
 793 #ifdef CONFIG_COMPAT
 794 static void compat_standard_from_user(void *dst, void *src)
 795 {
 796         int v = *(compat_int_t *)src;
 797
 798         if (v > 0)
 799                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 800         memcpy(dst, &v, sizeof(v));
 801 }
 802
 803 static int compat_standard_to_user(void __user *dst, void *src)
 804 {
 805         compat_int_t cv = *(int *)src;
 806
 807         if (cv > 0)
 808                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 809         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 810 }
 811
 812 static int compat_calc_entry(struct arpt_entry *e,
 813                              const struct xt_table_info *info,
 814                              void *base, struct xt_table_info *newinfo)
 815 {
 816         struct arpt_entry_target *t;
 817         unsigned int entry_offset;
 818         int off, i, ret;
 819
 820         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 821         entry_offset = (void *)e - base;
 822
 823         t = arpt_get_target(e);
 824         off += xt_compat_target_offset(t->u.kernel.target);
 825         newinfo->size -= off;
 826         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 827         if (ret)
 828                 return ret;
 829
 830         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 831                 if (info->hook_entry[i] &&
 832                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 833                         newinfo->hook_entry[i] -= off;
 834                 if (info->underflow[i] &&
 835                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 836                         newinfo->underflow[i] -= off;
 837         }
 838         return 0;
 839 }
 840
 841 static int compat_table_info(const struct xt_table_info *info,
 842                              struct xt_table_info *newinfo)
 843 {
 844         void *loc_cpu_entry;
 845
 846         if (!newinfo || !info)
 847                 return -EINVAL;
 848
 849         /* we dont care about newinfo->entries[] */
 850         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 851         newinfo->initial_entries = 0;
 852         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 853         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 854                                   compat_calc_entry, info, loc_cpu_entry,
 855                                   newinfo);
 856 }
 857 #endif
 858
 859 static int get_info(struct net *net, void __user *user, int *len, int compat)
 860 {
 861         char name[ARPT_TABLE_MAXNAMELEN];
 862         struct xt_table *t;
 863         int ret;
 864
 865         if (*len != sizeof(struct arpt_getinfo)) {
 866                 duprintf("length %u != %Zu\n", *len,
 867                          sizeof(struct arpt_getinfo));
 868                 return -EINVAL;
 869         }
 870
 871         if (copy_from_user(name, user, sizeof(name)) != 0)
 872                 return -EFAULT;
 873
 874         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 875 #ifdef CONFIG_COMPAT
 876         if (compat)
 877                 xt_compat_lock(NFPROTO_ARP);
 878 #endif
 879         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 880                                     "arptable_%s", name);
 881         if (t && !IS_ERR(t)) {
 882                 struct arpt_getinfo info;
 883                 const struct xt_table_info *private = t->private;
 884
 885 #ifdef CONFIG_COMPAT
 886                 if (compat) {
 887                         struct xt_table_info tmp;
 888                         ret = compat_table_info(private, &tmp);
 889                         xt_compat_flush_offsets(NFPROTO_ARP);
 890                         private = &tmp;
 891                 }
 892 #endif
 893                 info.valid_hooks = t->valid_hooks;
 894                 memcpy(info.hook_entry, private->hook_entry,
 895                        sizeof(info.hook_entry));
 896                 memcpy(info.underflow, private->underflow,
 897                        sizeof(info.underflow));
 898                 info.num_entries = private->number;
 899                 info.size = private->size;
 900                 strcpy(info.name, name);
 901
 902                 if (copy_to_user(user, &info, *len) != 0)
 903                         ret = -EFAULT;
 904                 else
 905                         ret = 0;
 906                 xt_table_unlock(t);
 907                 module_put(t->me);
 908         } else
 909                 ret = t ? PTR_ERR(t) : -ENOENT;
 910 #ifdef CONFIG_COMPAT
 911         if (compat)
 912                 xt_compat_unlock(NFPROTO_ARP);
 913 #endif
 914         return ret;
 915 }
 916
 917 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 918                        int *len)
 919 {
 920         int ret;
 921         struct arpt_get_entries get;
 922         struct xt_table *t;
 923
 924         if (*len < sizeof(get)) {
 925                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 926                 return -EINVAL;
 927         }
 928         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 929                 return -EFAULT;
 930         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 931                 duprintf("get_entries: %u != %Zu\n", *len,
 932                          sizeof(struct arpt_get_entries) + get.size);
 933                 return -EINVAL;
 934         }
 935
 936         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 937         if (t && !IS_ERR(t)) {
 938                 const struct xt_table_info *private = t->private;
 939
 940                 duprintf("t->private->number = %u\n",
 941                          private->number);
 942                 if (get.size == private->size)
 943                         ret = copy_entries_to_user(private->size,
 944                                                    t, uptr->entrytable);
 945                 else {
 946                         duprintf("get_entries: I've got %u not %u!\n",
 947                                  private->size, get.size);
 948                         ret = -EAGAIN;
 949                 }
 950                 module_put(t->me);
 951                 xt_table_unlock(t);
 952         } else
 953                 ret = t ? PTR_ERR(t) : -ENOENT;
 954
 955         return ret;
 956 }
 957
 958 static int __do_replace(struct net *net, const char *name,
 959                         unsigned int valid_hooks,
 960                         struct xt_table_info *newinfo,
 961                         unsigned int num_counters,
 962                         void __user *counters_ptr)
 963 {
 964         int ret;
 965         struct xt_table *t;
 966         struct xt_table_info *oldinfo;
 967         struct xt_counters *counters;
 968         void *loc_cpu_old_entry;
 969
 970         ret = 0;
 971         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
 972                                 numa_node_id());
 973         if (!counters) {
 974                 ret = -ENOMEM;
 975                 goto out;
 976         }
 977
 978         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 979                                     "arptable_%s", name);
 980         if (!t || IS_ERR(t)) {
 981                 ret = t ? PTR_ERR(t) : -ENOENT;
 982                 goto free_newinfo_counters_untrans;
 983         }
 984
 985         /* You lied! */
 986         if (valid_hooks != t->valid_hooks) {
 987                 duprintf("Valid hook crap: %08X vs %08X\n",
 988                          valid_hooks, t->valid_hooks);
 989                 ret = -EINVAL;
 990                 goto put_module;
 991         }
 992
 993         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
 994         if (!oldinfo)
 995                 goto put_module;
 996
 997         /* Update module usage count based on number of rules */
 998         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
 999                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1000         if ((oldinfo->number > oldinfo->initial_entries) ||
1001             (newinfo->number <= oldinfo->initial_entries))
1002                 module_put(t->me);
1003         if ((oldinfo->number > oldinfo->initial_entries) &&
1004             (newinfo->number <= oldinfo->initial_entries))
1005                 module_put(t->me);
1006
1007         /* Get the old counters. */
1008         get_counters(oldinfo, counters);
1009         /* Decrease module usage counts and free resource */
1010         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1011         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1012                            NULL);
1013
1014         xt_free_table_info(oldinfo);
1015         if (copy_to_user(counters_ptr, counters,
1016                          sizeof(struct xt_counters) * num_counters) != 0)
1017                 ret = -EFAULT;
1018         vfree(counters);
1019         xt_table_unlock(t);
1020         return ret;
1021
1022  put_module:
1023         module_put(t->me);
1024         xt_table_unlock(t);
1025  free_newinfo_counters_untrans:
1026         vfree(counters);
1027  out:
1028         return ret;
1029 }
1030
1031 static int do_replace(struct net *net, void __user *user, unsigned int len)
1032 {
1033         int ret;
1034         struct arpt_replace tmp;
1035         struct xt_table_info *newinfo;
1036         void *loc_cpu_entry;
1037
1038         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1039                 return -EFAULT;
1040
1041         /* overflow check */
1042         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1043                 return -ENOMEM;
1044
1045         newinfo = xt_alloc_table_info(tmp.size);
1046         if (!newinfo)
1047                 return -ENOMEM;
1048
1049         /* choose the copy that is on our node/cpu */
1050         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1051         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1052                            tmp.size) != 0) {
1053                 ret = -EFAULT;
1054                 goto free_newinfo;
1055         }
1056
1057         ret = translate_table(tmp.name, tmp.valid_hooks,
1058                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1059                               tmp.hook_entry, tmp.underflow);
1060         if (ret != 0)
1061                 goto free_newinfo;
1062
1063         duprintf("arp_tables: Translated table\n");
1064
1065         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1066                            tmp.num_counters, tmp.counters);
1067         if (ret)
1068                 goto free_newinfo_untrans;
1069         return 0;
1070
1071  free_newinfo_untrans:
1072         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1073  free_newinfo:
1074         xt_free_table_info(newinfo);
1075         return ret;
1076 }
1077
1078 /* We're lazy, and add to the first CPU; overflow works its fey magic
1079  * and everything is OK.
1080  */
1081 static inline int add_counter_to_entry(struct arpt_entry *e,
1082                                        const struct xt_counters addme[],
1083                                        unsigned int *i)
1084 {
1085
1086         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1087
1088         (*i)++;
1089         return 0;
1090 }
1091
1092 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1093                            int compat)
1094 {
1095         unsigned int i;
1096         struct xt_counters_info tmp;
1097         struct xt_counters *paddc;
1098         unsigned int num_counters;
1099         const char *name;
1100         int size;
1101         void *ptmp;
1102         struct xt_table *t;
1103         const struct xt_table_info *private;
1104         int ret = 0;
1105         void *loc_cpu_entry;
1106 #ifdef CONFIG_COMPAT
1107         struct compat_xt_counters_info compat_tmp;
1108
1109         if (compat) {
1110                 ptmp = &compat_tmp;
1111                 size = sizeof(struct compat_xt_counters_info);
1112         } else
1113 #endif
1114         {
1115                 ptmp = &tmp;
1116                 size = sizeof(struct xt_counters_info);
1117         }
1118
1119         if (copy_from_user(ptmp, user, size) != 0)
1120                 return -EFAULT;
1121
1122 #ifdef CONFIG_COMPAT
1123         if (compat) {
1124                 num_counters = compat_tmp.num_counters;
1125                 name = compat_tmp.name;
1126         } else
1127 #endif
1128         {
1129                 num_counters = tmp.num_counters;
1130                 name = tmp.name;
1131         }
1132
1133         if (len != size + num_counters * sizeof(struct xt_counters))
1134                 return -EINVAL;
1135
1136         paddc = vmalloc_node(len - size, numa_node_id());
1137         if (!paddc)
1138                 return -ENOMEM;
1139
1140         if (copy_from_user(paddc, user + size, len - size) != 0) {
1141                 ret = -EFAULT;
1142                 goto free;
1143         }
1144
1145         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1146         if (!t || IS_ERR(t)) {
1147                 ret = t ? PTR_ERR(t) : -ENOENT;
1148                 goto free;
1149         }
1150
1151         write_lock_bh(&t->lock);
1152         private = t->private;
1153         if (private->number != num_counters) {
1154                 ret = -EINVAL;
1155                 goto unlock_up_free;
1156         }
1157
1158         i = 0;
1159         /* Choose the copy that is on our node */
1160         loc_cpu_entry = private->entries[smp_processor_id()];
1161         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1162                            private->size,
1163                            add_counter_to_entry,
1164                            paddc,
1165                            &i);
1166  unlock_up_free:
1167         write_unlock_bh(&t->lock);
1168         xt_table_unlock(t);
1169         module_put(t->me);
1170  free:
1171         vfree(paddc);
1172
1173         return ret;
1174 }
1175
1176 #ifdef CONFIG_COMPAT
1177 static inline int
1178 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1179 {
1180         struct arpt_entry_target *t;
1181
1182         if (i && (*i)-- == 0)
1183                 return 1;
1184
1185         t = compat_arpt_get_target(e);
1186         module_put(t->u.kernel.target->me);
1187         return 0;
1188 }
1189
1190 static inline int
1191 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1192                                   struct xt_table_info *newinfo,
1193                                   unsigned int *size,
1194                                   unsigned char *base,
1195                                   unsigned char *limit,
1196                                   unsigned int *hook_entries,
1197                                   unsigned int *underflows,
1198                                   unsigned int *i,
1199                                   const char *name)
1200 {
1201         struct arpt_entry_target *t;
1202         struct xt_target *target;
1203         unsigned int entry_offset;
1204         int ret, off, h;
1205
1206         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1207         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1208             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1209                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1210                 return -EINVAL;
1211         }
1212
1213         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1214                              sizeof(struct compat_xt_entry_target)) {
1215                 duprintf("checking: element %p size %u\n",
1216                          e, e->next_offset);
1217                 return -EINVAL;
1218         }
1219
1220         /* For purposes of check_entry casting the compat entry is fine */
1221         ret = check_entry((struct arpt_entry *)e, name);
1222         if (ret)
1223                 return ret;
1224
1225         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1226         entry_offset = (void *)e - (void *)base;
1227
1228         t = compat_arpt_get_target(e);
1229         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1230                                                         t->u.user.name,
1231                                                         t->u.user.revision),
1232                                          "arpt_%s", t->u.user.name);
1233         if (IS_ERR(target) || !target) {
1234                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1235                          t->u.user.name);
1236                 ret = target ? PTR_ERR(target) : -ENOENT;
1237                 goto out;
1238         }
1239         t->u.kernel.target = target;
1240
1241         off += xt_compat_target_offset(target);
1242         *size += off;
1243         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1244         if (ret)
1245                 goto release_target;
1246
1247         /* Check hooks & underflows */
1248         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1249                 if ((unsigned char *)e - base == hook_entries[h])
1250                         newinfo->hook_entry[h] = hook_entries[h];
1251                 if ((unsigned char *)e - base == underflows[h])
1252                         newinfo->underflow[h] = underflows[h];
1253         }
1254
1255         /* Clear counters and comefrom */
1256         memset(&e->counters, 0, sizeof(e->counters));
1257         e->comefrom = 0;
1258
1259         (*i)++;
1260         return 0;
1261
1262 release_target:
1263         module_put(t->u.kernel.target->me);
1264 out:
1265         return ret;
1266 }
1267
1268 static int
1269 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1270                             unsigned int *size, const char *name,
1271                             struct xt_table_info *newinfo, unsigned char *base)
1272 {
1273         struct arpt_entry_target *t;
1274         struct xt_target *target;
1275         struct arpt_entry *de;
1276         unsigned int origsize;
1277         int ret, h;
1278
1279         ret = 0;
1280         origsize = *size;
1281         de = (struct arpt_entry *)*dstptr;
1282         memcpy(de, e, sizeof(struct arpt_entry));
1283         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1284
1285         *dstptr += sizeof(struct arpt_entry);
1286         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1287
1288         de->target_offset = e->target_offset - (origsize - *size);
1289         t = compat_arpt_get_target(e);
1290         target = t->u.kernel.target;
1291         xt_compat_target_from_user(t, dstptr, size);
1292
1293         de->next_offset = e->next_offset - (origsize - *size);
1294         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1295                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1296                         newinfo->hook_entry[h] -= origsize - *size;
1297                 if ((unsigned char *)de - base < newinfo->underflow[h])
1298                         newinfo->underflow[h] -= origsize - *size;
1299         }
1300         return ret;
1301 }
1302
1303 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1304                                      unsigned int *i)
1305 {
1306         int ret;
1307
1308         ret = check_target(e, name);
1309         if (ret)
1310                 return ret;
1311
1312         (*i)++;
1313         return 0;
1314 }
1315
1316 static int translate_compat_table(const char *name,
1317                                   unsigned int valid_hooks,
1318                                   struct xt_table_info **pinfo,
1319                                   void **pentry0,
1320                                   unsigned int total_size,
1321                                   unsigned int number,
1322                                   unsigned int *hook_entries,
1323                                   unsigned int *underflows)
1324 {
1325         unsigned int i, j;
1326         struct xt_table_info *newinfo, *info;
1327         void *pos, *entry0, *entry1;
1328         unsigned int size;
1329         int ret;
1330
1331         info = *pinfo;
1332         entry0 = *pentry0;
1333         size = total_size;
1334         info->number = number;
1335
1336         /* Init all hooks to impossible value. */
1337         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1338                 info->hook_entry[i] = 0xFFFFFFFF;
1339                 info->underflow[i] = 0xFFFFFFFF;
1340         }
1341
1342         duprintf("translate_compat_table: size %u\n", info->size);
1343         j = 0;
1344         xt_compat_lock(NFPROTO_ARP);
1345         /* Walk through entries, checking offsets. */
1346         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1347                                         check_compat_entry_size_and_hooks,
1348                                         info, &size, entry0,
1349                                         entry0 + total_size,
1350                                         hook_entries, underflows, &j, name);
1351         if (ret != 0)
1352                 goto out_unlock;
1353
1354         ret = -EINVAL;
1355         if (j != number) {
1356                 duprintf("translate_compat_table: %u not %u entries\n",
1357                          j, number);
1358                 goto out_unlock;
1359         }
1360
1361         /* Check hooks all assigned */
1362         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1363                 /* Only hooks which are valid */
1364                 if (!(valid_hooks & (1 << i)))
1365                         continue;
1366                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1367                         duprintf("Invalid hook entry %u %u\n",
1368                                  i, hook_entries[i]);
1369                         goto out_unlock;
1370                 }
1371                 if (info->underflow[i] == 0xFFFFFFFF) {
1372                         duprintf("Invalid underflow %u %u\n",
1373                                  i, underflows[i]);
1374                         goto out_unlock;
1375                 }
1376         }
1377
1378         ret = -ENOMEM;
1379         newinfo = xt_alloc_table_info(size);
1380         if (!newinfo)
1381                 goto out_unlock;
1382
1383         newinfo->number = number;
1384         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1385                 newinfo->hook_entry[i] = info->hook_entry[i];
1386                 newinfo->underflow[i] = info->underflow[i];
1387         }
1388         entry1 = newinfo->entries[raw_smp_processor_id()];
1389         pos = entry1;
1390         size = total_size;
1391         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1392                                         compat_copy_entry_from_user,
1393                                         &pos, &size, name, newinfo, entry1);
1394         xt_compat_flush_offsets(NFPROTO_ARP);
1395         xt_compat_unlock(NFPROTO_ARP);
1396         if (ret)
1397                 goto free_newinfo;
1398
1399         ret = -ELOOP;
1400         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1401                 goto free_newinfo;
1402
1403         i = 0;
1404         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1405                                  name, &i);
1406         if (ret) {
1407                 j -= i;
1408                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1409                                                    compat_release_entry, &j);
1410                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1411                 xt_free_table_info(newinfo);
1412                 return ret;
1413         }
1414
1415         /* And one copy for every other CPU */
1416         for_each_possible_cpu(i)
1417                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1418                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1419
1420         *pinfo = newinfo;
1421         *pentry0 = entry1;
1422         xt_free_table_info(info);
1423         return 0;
1424
1425 free_newinfo:
1426         xt_free_table_info(newinfo);
1427 out:
1428         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1429         return ret;
1430 out_unlock:
1431         xt_compat_flush_offsets(NFPROTO_ARP);
1432         xt_compat_unlock(NFPROTO_ARP);
1433         goto out;
1434 }
1435
1436 struct compat_arpt_replace {
1437         char                            name[ARPT_TABLE_MAXNAMELEN];
1438         u32                             valid_hooks;
1439         u32                             num_entries;
1440         u32                             size;
1441         u32                             hook_entry[NF_ARP_NUMHOOKS];
1442         u32                             underflow[NF_ARP_NUMHOOKS];
1443         u32                             num_counters;
1444         compat_uptr_t                   counters;
1445         struct compat_arpt_entry        entries[0];
1446 };
1447
1448 static int compat_do_replace(struct net *net, void __user *user,
1449                              unsigned int len)
1450 {
1451         int ret;
1452         struct compat_arpt_replace tmp;
1453         struct xt_table_info *newinfo;
1454         void *loc_cpu_entry;
1455
1456         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1457                 return -EFAULT;
1458
1459         /* overflow check */
1460         if (tmp.size >= INT_MAX / num_possible_cpus())
1461                 return -ENOMEM;
1462         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1463                 return -ENOMEM;
1464
1465         newinfo = xt_alloc_table_info(tmp.size);
1466         if (!newinfo)
1467                 return -ENOMEM;
1468
1469         /* choose the copy that is on our node/cpu */
1470         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1471         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1472                 ret = -EFAULT;
1473                 goto free_newinfo;
1474         }
1475
1476         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1477                                      &newinfo, &loc_cpu_entry, tmp.size,
1478                                      tmp.num_entries, tmp.hook_entry,
1479                                      tmp.underflow);
1480         if (ret != 0)
1481                 goto free_newinfo;
1482
1483         duprintf("compat_do_replace: Translated table\n");
1484
1485         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1486                            tmp.num_counters, compat_ptr(tmp.counters));
1487         if (ret)
1488                 goto free_newinfo_untrans;
1489         return 0;
1490
1491  free_newinfo_untrans:
1492         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1493  free_newinfo:
1494         xt_free_table_info(newinfo);
1495         return ret;
1496 }
1497
1498 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1499                                   unsigned int len)
1500 {
1501         int ret;
1502
1503         if (!capable(CAP_NET_ADMIN))
1504                 return -EPERM;
1505
1506         switch (cmd) {
1507         case ARPT_SO_SET_REPLACE:
1508                 ret = compat_do_replace(sock_net(sk), user, len);
1509                 break;
1510
1511         case ARPT_SO_SET_ADD_COUNTERS:
1512                 ret = do_add_counters(sock_net(sk), user, len, 1);
1513                 break;
1514
1515         default:
1516                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1517                 ret = -EINVAL;
1518         }
1519
1520         return ret;
1521 }
1522
1523 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1524                                      compat_uint_t *size,
1525                                      struct xt_counters *counters,
1526                                      unsigned int *i)
1527 {
1528         struct arpt_entry_target *t;
1529         struct compat_arpt_entry __user *ce;
1530         u_int16_t target_offset, next_offset;
1531         compat_uint_t origsize;
1532         int ret;
1533
1534         ret = -EFAULT;
1535         origsize = *size;
1536         ce = (struct compat_arpt_entry __user *)*dstptr;
1537         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1538                 goto out;
1539
1540         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1541                 goto out;
1542
1543         *dstptr += sizeof(struct compat_arpt_entry);
1544         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1545
1546         target_offset = e->target_offset - (origsize - *size);
1547
1548         t = arpt_get_target(e);
1549         ret = xt_compat_target_to_user(t, dstptr, size);
1550         if (ret)
1551                 goto out;
1552         ret = -EFAULT;
1553         next_offset = e->next_offset - (origsize - *size);
1554         if (put_user(target_offset, &ce->target_offset))
1555                 goto out;
1556         if (put_user(next_offset, &ce->next_offset))
1557                 goto out;
1558
1559         (*i)++;
1560         return 0;
1561 out:
1562         return ret;
1563 }
1564
1565 static int compat_copy_entries_to_user(unsigned int total_size,
1566                                        struct xt_table *table,
1567                                        void __user *userptr)
1568 {
1569         struct xt_counters *counters;
1570         const struct xt_table_info *private = table->private;
1571         void __user *pos;
1572         unsigned int size;
1573         int ret = 0;
1574         void *loc_cpu_entry;
1575         unsigned int i = 0;
1576
1577         counters = alloc_counters(table);
1578         if (IS_ERR(counters))
1579                 return PTR_ERR(counters);
1580
1581         /* choose the copy on our node/cpu */
1582         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1583         pos = userptr;
1584         size = total_size;
1585         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1586                                  compat_copy_entry_to_user,
1587                                  &pos, &size, counters, &i);
1588         vfree(counters);
1589         return ret;
1590 }
1591
1592 struct compat_arpt_get_entries {
1593         char name[ARPT_TABLE_MAXNAMELEN];
1594         compat_uint_t size;
1595         struct compat_arpt_entry entrytable[0];
1596 };
1597
1598 static int compat_get_entries(struct net *net,
1599                               struct compat_arpt_get_entries __user *uptr,
1600                               int *len)
1601 {
1602         int ret;
1603         struct compat_arpt_get_entries get;
1604         struct xt_table *t;
1605
1606         if (*len < sizeof(get)) {
1607                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1608                 return -EINVAL;
1609         }
1610         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1611                 return -EFAULT;
1612         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1613                 duprintf("compat_get_entries: %u != %zu\n",
1614                          *len, sizeof(get) + get.size);
1615                 return -EINVAL;
1616         }
1617
1618         xt_compat_lock(NFPROTO_ARP);
1619         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1620         if (t && !IS_ERR(t)) {
1621                 const struct xt_table_info *private = t->private;
1622                 struct xt_table_info info;
1623
1624                 duprintf("t->private->number = %u\n", private->number);
1625                 ret = compat_table_info(private, &info);
1626                 if (!ret && get.size == info.size) {
1627                         ret = compat_copy_entries_to_user(private->size,
1628                                                           t, uptr->entrytable);
1629                 } else if (!ret) {
1630                         duprintf("compat_get_entries: I've got %u not %u!\n",
1631                                  private->size, get.size);
1632                         ret = -EAGAIN;
1633                 }
1634                 xt_compat_flush_offsets(NFPROTO_ARP);
1635                 module_put(t->me);
1636                 xt_table_unlock(t);
1637         } else
1638                 ret = t ? PTR_ERR(t) : -ENOENT;
1639
1640         xt_compat_unlock(NFPROTO_ARP);
1641         return ret;
1642 }
1643
1644 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1645
1646 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1647                                   int *len)
1648 {
1649         int ret;
1650
1651         if (!capable(CAP_NET_ADMIN))
1652                 return -EPERM;
1653
1654         switch (cmd) {
1655         case ARPT_SO_GET_INFO:
1656                 ret = get_info(sock_net(sk), user, len, 1);
1657                 break;
1658         case ARPT_SO_GET_ENTRIES:
1659                 ret = compat_get_entries(sock_net(sk), user, len);
1660                 break;
1661         default:
1662                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1663         }
1664         return ret;
1665 }
1666 #endif
1667
1668 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1669 {
1670         int ret;
1671
1672         if (!capable(CAP_NET_ADMIN))
1673                 return -EPERM;
1674
1675         switch (cmd) {
1676         case ARPT_SO_SET_REPLACE:
1677                 ret = do_replace(sock_net(sk), user, len);
1678                 break;
1679
1680         case ARPT_SO_SET_ADD_COUNTERS:
1681                 ret = do_add_counters(sock_net(sk), user, len, 0);
1682                 break;
1683
1684         default:
1685                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1686                 ret = -EINVAL;
1687         }
1688
1689         return ret;
1690 }
1691
1692 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1693 {
1694         int ret;
1695
1696         if (!capable(CAP_NET_ADMIN))
1697                 return -EPERM;
1698
1699         switch (cmd) {
1700         case ARPT_SO_GET_INFO:
1701                 ret = get_info(sock_net(sk), user, len, 0);
1702                 break;
1703
1704         case ARPT_SO_GET_ENTRIES:
1705                 ret = get_entries(sock_net(sk), user, len);
1706                 break;
1707
1708         case ARPT_SO_GET_REVISION_TARGET: {
1709                 struct xt_get_revision rev;
1710
1711                 if (*len != sizeof(rev)) {
1712                         ret = -EINVAL;
1713                         break;
1714                 }
1715                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1716                         ret = -EFAULT;
1717                         break;
1718                 }
1719
1720                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1721                                                          rev.revision, 1, &ret),
1722                                         "arpt_%s", rev.name);
1723                 break;
1724         }
1725
1726         default:
1727                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1728                 ret = -EINVAL;
1729         }
1730
1731         return ret;
1732 }
1733
1734 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1735                                      const struct arpt_replace *repl)
1736 {
1737         int ret;
1738         struct xt_table_info *newinfo;
1739         struct xt_table_info bootstrap
1740                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1741         void *loc_cpu_entry;
1742         struct xt_table *new_table;
1743
1744         newinfo = xt_alloc_table_info(repl->size);
1745         if (!newinfo) {
1746                 ret = -ENOMEM;
1747                 goto out;
1748         }
1749
1750         /* choose the copy on our node/cpu */
1751         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1752         memcpy(loc_cpu_entry, repl->entries, repl->size);
1753
1754         ret = translate_table(table->name, table->valid_hooks,
1755                               newinfo, loc_cpu_entry, repl->size,
1756                               repl->num_entries,
1757                               repl->hook_entry,
1758                               repl->underflow);
1759
1760         duprintf("arpt_register_table: translate table gives %d\n", ret);
1761         if (ret != 0)
1762                 goto out_free;
1763
1764         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1765         if (IS_ERR(new_table)) {
1766                 ret = PTR_ERR(new_table);
1767                 goto out_free;
1768         }
1769         return new_table;
1770
1771 out_free:
1772         xt_free_table_info(newinfo);
1773 out:
1774         return ERR_PTR(ret);
1775 }
1776
1777 void arpt_unregister_table(struct xt_table *table)
1778 {
1779         struct xt_table_info *private;
1780         void *loc_cpu_entry;
1781         struct module *table_owner = table->me;
1782
1783         private = xt_unregister_table(table);
1784
1785         /* Decrease module usage counts and free resources */
1786         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1787         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1788                            cleanup_entry, NULL);
1789         if (private->number > private->initial_entries)
1790                 module_put(table_owner);
1791         xt_free_table_info(private);
1792 }
1793
1794 /* The built-in targets: standard (NULL) and error. */
1795 static struct xt_target arpt_standard_target __read_mostly = {
1796         .name           = ARPT_STANDARD_TARGET,
1797         .targetsize     = sizeof(int),
1798         .family         = NFPROTO_ARP,
1799 #ifdef CONFIG_COMPAT
1800         .compatsize     = sizeof(compat_int_t),
1801         .compat_from_user = compat_standard_from_user,
1802         .compat_to_user = compat_standard_to_user,
1803 #endif
1804 };
1805
1806 static struct xt_target arpt_error_target __read_mostly = {
1807         .name           = ARPT_ERROR_TARGET,
1808         .target         = arpt_error,
1809         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1810         .family         = NFPROTO_ARP,
1811 };
1812
1813 static struct nf_sockopt_ops arpt_sockopts = {
1814         .pf             = PF_INET,
1815         .set_optmin     = ARPT_BASE_CTL,
1816         .set_optmax     = ARPT_SO_SET_MAX+1,
1817         .set            = do_arpt_set_ctl,
1818 #ifdef CONFIG_COMPAT
1819         .compat_set     = compat_do_arpt_set_ctl,
1820 #endif
1821         .get_optmin     = ARPT_BASE_CTL,
1822         .get_optmax     = ARPT_SO_GET_MAX+1,
1823         .get            = do_arpt_get_ctl,
1824 #ifdef CONFIG_COMPAT
1825         .compat_get     = compat_do_arpt_get_ctl,
1826 #endif
1827         .owner          = THIS_MODULE,
1828 };
1829
1830 static int __net_init arp_tables_net_init(struct net *net)
1831 {
1832         return xt_proto_init(net, NFPROTO_ARP);
1833 }
1834
1835 static void __net_exit arp_tables_net_exit(struct net *net)
1836 {
1837         xt_proto_fini(net, NFPROTO_ARP);
1838 }
1839
1840 static struct pernet_operations arp_tables_net_ops = {
1841         .init = arp_tables_net_init,
1842         .exit = arp_tables_net_exit,
1843 };
1844
1845 static int __init arp_tables_init(void)
1846 {
1847         int ret;
1848
1849         ret = register_pernet_subsys(&arp_tables_net_ops);
1850         if (ret < 0)
1851                 goto err1;
1852
1853         /* Noone else will be downing sem now, so we won't sleep */
1854         ret = xt_register_target(&arpt_standard_target);
1855         if (ret < 0)
1856                 goto err2;
1857         ret = xt_register_target(&arpt_error_target);
1858         if (ret < 0)
1859                 goto err3;
1860
1861         /* Register setsockopt */
1862         ret = nf_register_sockopt(&arpt_sockopts);
1863         if (ret < 0)
1864                 goto err4;
1865
1866         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1867         return 0;
1868
1869 err4:
1870         xt_unregister_target(&arpt_error_target);
1871 err3:
1872         xt_unregister_target(&arpt_standard_target);
1873 err2:
1874         unregister_pernet_subsys(&arp_tables_net_ops);
1875 err1:
1876         return ret;
1877 }
1878
1879 static void __exit arp_tables_fini(void)
1880 {
1881         nf_unregister_sockopt(&arpt_sockopts);
1882         xt_unregister_target(&arpt_error_target);
1883         xt_unregister_target(&arpt_standard_target);
1884         unregister_pernet_subsys(&arp_tables_net_ops);
1885 }
1886
1887 EXPORT_SYMBOL(arpt_register_table);
1888 EXPORT_SYMBOL(arpt_unregister_table);
1889 EXPORT_SYMBOL(arpt_do_table);
1890
1891 module_init(arp_tables_init);
1892 module_exit(arp_tables_fini);