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   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  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 #include "../../netfilter/xt_repldata.h"
  31
  32 MODULE_LICENSE("GPL");
  33 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  34 MODULE_DESCRIPTION("arptables core");
  35
  36 /*#define DEBUG_ARP_TABLES*/
  37 /*#define DEBUG_ARP_TABLES_USER*/
  38
  39 #ifdef DEBUG_ARP_TABLES
  40 #define dprintf(format, args...)  printk(format , ## args)
  41 #else
  42 #define dprintf(format, args...)
  43 #endif
  44
  45 #ifdef DEBUG_ARP_TABLES_USER
  46 #define duprintf(format, args...) printk(format , ## args)
  47 #else
  48 #define duprintf(format, args...)
  49 #endif
  50
  51 #ifdef CONFIG_NETFILTER_DEBUG
  52 #define ARP_NF_ASSERT(x)                                        \
  53 do {                                                            \
  54         if (!(x))                                               \
  55                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  56                        __func__, __FILE__, __LINE__);   \
  57 } while(0)
  58 #else
  59 #define ARP_NF_ASSERT(x)
  60 #endif
  61
  62 void *arpt_alloc_initial_table(const struct xt_table *info)
  63 {
  64         return xt_alloc_initial_table(arpt, ARPT);
  65 }
  66 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  67
  68 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  69                                       const char *hdr_addr, int len)
  70 {
  71         int i, ret;
  72
  73         if (len > ARPT_DEV_ADDR_LEN_MAX)
  74                 len = ARPT_DEV_ADDR_LEN_MAX;
  75
  76         ret = 0;
  77         for (i = 0; i < len; i++)
  78                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  79
  80         return (ret != 0);
  81 }
  82
  83 /*
  84  * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  85  * Some arches dont care, unrolling the loop is a win on them.
  86  * For other arches, we only have a 16bit alignement.
  87  */
  88 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  89 {
  90 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  91         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  92 #else
  93         unsigned long ret = 0;
  94         const u16 *a = (const u16 *)_a;
  95         const u16 *b = (const u16 *)_b;
  96         const u16 *mask = (const u16 *)_mask;
  97         int i;
  98
  99         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
 100                 ret |= (a[i] ^ b[i]) & mask[i];
 101 #endif
 102         return ret;
 103 }
 104
 105 /* Returns whether packet matches rule or not. */
 106 static inline int arp_packet_match(const struct arphdr *arphdr,
 107                                    struct net_device *dev,
 108                                    const char *indev,
 109                                    const char *outdev,
 110                                    const struct arpt_arp *arpinfo)
 111 {
 112         const char *arpptr = (char *)(arphdr + 1);
 113         const char *src_devaddr, *tgt_devaddr;
 114         __be32 src_ipaddr, tgt_ipaddr;
 115         long ret;
 116
 117 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 118
 119         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 120                   ARPT_INV_ARPOP)) {
 121                 dprintf("ARP operation field mismatch.\n");
 122                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 123                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 124                 return 0;
 125         }
 126
 127         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 128                   ARPT_INV_ARPHRD)) {
 129                 dprintf("ARP hardware address format mismatch.\n");
 130                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 131                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 132                 return 0;
 133         }
 134
 135         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 136                   ARPT_INV_ARPPRO)) {
 137                 dprintf("ARP protocol address format mismatch.\n");
 138                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 139                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 140                 return 0;
 141         }
 142
 143         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 144                   ARPT_INV_ARPHLN)) {
 145                 dprintf("ARP hardware address length mismatch.\n");
 146                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 147                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 148                 return 0;
 149         }
 150
 151         src_devaddr = arpptr;
 152         arpptr += dev->addr_len;
 153         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 154         arpptr += sizeof(u32);
 155         tgt_devaddr = arpptr;
 156         arpptr += dev->addr_len;
 157         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 158
 159         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 160                   ARPT_INV_SRCDEVADDR) ||
 161             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 162                   ARPT_INV_TGTDEVADDR)) {
 163                 dprintf("Source or target device address mismatch.\n");
 164
 165                 return 0;
 166         }
 167
 168         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 169                   ARPT_INV_SRCIP) ||
 170             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 171                   ARPT_INV_TGTIP)) {
 172                 dprintf("Source or target IP address mismatch.\n");
 173
 174                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 175                         &src_ipaddr,
 176                         &arpinfo->smsk.s_addr,
 177                         &arpinfo->src.s_addr,
 178                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 179                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 180                         &tgt_ipaddr,
 181                         &arpinfo->tmsk.s_addr,
 182                         &arpinfo->tgt.s_addr,
 183                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 184                 return 0;
 185         }
 186
 187         /* Look for ifname matches.  */
 188         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 189
 190         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 191                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 192                         indev, arpinfo->iniface,
 193                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 194                 return 0;
 195         }
 196
 197         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 198
 199         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 200                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 201                         outdev, arpinfo->outiface,
 202                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 203                 return 0;
 204         }
 205
 206         return 1;
 207 #undef FWINV
 208 }
 209
 210 static inline int arp_checkentry(const struct arpt_arp *arp)
 211 {
 212         if (arp->flags & ~ARPT_F_MASK) {
 213                 duprintf("Unknown flag bits set: %08X\n",
 214                          arp->flags & ~ARPT_F_MASK);
 215                 return 0;
 216         }
 217         if (arp->invflags & ~ARPT_INV_MASK) {
 218                 duprintf("Unknown invflag bits set: %08X\n",
 219                          arp->invflags & ~ARPT_INV_MASK);
 220                 return 0;
 221         }
 222
 223         return 1;
 224 }
 225
 226 static unsigned int
 227 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 228 {
 229         if (net_ratelimit())
 230                 printk("arp_tables: error: '%s'\n",
 231                        (const char *)par->targinfo);
 232
 233         return NF_DROP;
 234 }
 235
 236 static inline const struct arpt_entry_target *
 237 arpt_get_target_c(const struct arpt_entry *e)
 238 {
 239         return arpt_get_target((struct arpt_entry *)e);
 240 }
 241
 242 static inline struct arpt_entry *
 243 get_entry(const void *base, unsigned int offset)
 244 {
 245         return (struct arpt_entry *)(base + offset);
 246 }
 247
 248 static inline __pure
 249 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 250 {
 251         return (void *)entry + entry->next_offset;
 252 }
 253
 254 unsigned int arpt_do_table(struct sk_buff *skb,
 255                            unsigned int hook,
 256                            const struct net_device *in,
 257                            const struct net_device *out,
 258                            struct xt_table *table)
 259 {
 260         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 261         unsigned int verdict = NF_DROP;
 262         const struct arphdr *arp;
 263         bool hotdrop = false;
 264         struct arpt_entry *e, *back;
 265         const char *indev, *outdev;
 266         void *table_base;
 267         const struct xt_table_info *private;
 268         struct xt_target_param tgpar;
 269
 270         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 271                 return NF_DROP;
 272
 273         indev = in ? in->name : nulldevname;
 274         outdev = out ? out->name : nulldevname;
 275
 276         xt_info_rdlock_bh();
 277         private = table->private;
 278         table_base = private->entries[smp_processor_id()];
 279
 280         e = get_entry(table_base, private->hook_entry[hook]);
 281         back = get_entry(table_base, private->underflow[hook]);
 282
 283         tgpar.in      = in;
 284         tgpar.out     = out;
 285         tgpar.hooknum = hook;
 286         tgpar.family  = NFPROTO_ARP;
 287
 288         arp = arp_hdr(skb);
 289         do {
 290                 const struct arpt_entry_target *t;
 291                 int hdr_len;
 292
 293                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 294                         e = arpt_next_entry(e);
 295                         continue;
 296                 }
 297
 298                 hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 299                         (2 * skb->dev->addr_len);
 300                 ADD_COUNTER(e->counters, hdr_len, 1);
 301
 302                 t = arpt_get_target_c(e);
 303
 304                 /* Standard target? */
 305                 if (!t->u.kernel.target->target) {
 306                         int v;
 307
 308                         v = ((struct arpt_standard_target *)t)->verdict;
 309                         if (v < 0) {
 310                                 /* Pop from stack? */
 311                                 if (v != ARPT_RETURN) {
 312                                         verdict = (unsigned)(-v) - 1;
 313                                         break;
 314                                 }
 315                                 e = back;
 316                                 back = get_entry(table_base, back->comefrom);
 317                                 continue;
 318                         }
 319                         if (table_base + v
 320                             != arpt_next_entry(e)) {
 321                                 /* Save old back ptr in next entry */
 322                                 struct arpt_entry *next = arpt_next_entry(e);
 323                                 next->comefrom = (void *)back - table_base;
 324
 325                                 /* set back pointer to next entry */
 326                                 back = next;
 327                         }
 328
 329                         e = get_entry(table_base, v);
 330                         continue;
 331                 }
 332
 333                 /* Targets which reenter must return
 334                  * abs. verdicts
 335                  */
 336                 tgpar.target   = t->u.kernel.target;
 337                 tgpar.targinfo = t->data;
 338                 verdict = t->u.kernel.target->target(skb, &tgpar);
 339
 340                 /* Target might have changed stuff. */
 341                 arp = arp_hdr(skb);
 342
 343                 if (verdict == ARPT_CONTINUE)
 344                         e = arpt_next_entry(e);
 345                 else
 346                         /* Verdict */
 347                         break;
 348         } while (!hotdrop);
 349         xt_info_rdunlock_bh();
 350
 351         if (hotdrop)
 352                 return NF_DROP;
 353         else
 354                 return verdict;
 355 }
 356
 357 /* All zeroes == unconditional rule. */
 358 static inline bool unconditional(const struct arpt_arp *arp)
 359 {
 360         static const struct arpt_arp uncond;
 361
 362         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 363 }
 364
 365 /* Figures out from what hook each rule can be called: returns 0 if
 366  * there are loops.  Puts hook bitmask in comefrom.
 367  */
 368 static int mark_source_chains(const struct xt_table_info *newinfo,
 369                               unsigned int valid_hooks, void *entry0)
 370 {
 371         unsigned int hook;
 372
 373         /* No recursion; use packet counter to save back ptrs (reset
 374          * to 0 as we leave), and comefrom to save source hook bitmask.
 375          */
 376         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 377                 unsigned int pos = newinfo->hook_entry[hook];
 378                 struct arpt_entry *e
 379                         = (struct arpt_entry *)(entry0 + pos);
 380
 381                 if (!(valid_hooks & (1 << hook)))
 382                         continue;
 383
 384                 /* Set initial back pointer. */
 385                 e->counters.pcnt = pos;
 386
 387                 for (;;) {
 388                         const struct arpt_standard_target *t
 389                                 = (void *)arpt_get_target_c(e);
 390                         int visited = e->comefrom & (1 << hook);
 391
 392                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 393                                 printk("arptables: loop hook %u pos %u %08X.\n",
 394                                        hook, pos, e->comefrom);
 395                                 return 0;
 396                         }
 397                         e->comefrom
 398                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 399
 400                         /* Unconditional return/END. */
 401                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 402                              (strcmp(t->target.u.user.name,
 403                                      ARPT_STANDARD_TARGET) == 0) &&
 404                              t->verdict < 0 && unconditional(&e->arp)) ||
 405                             visited) {
 406                                 unsigned int oldpos, size;
 407
 408                                 if ((strcmp(t->target.u.user.name,
 409                                             ARPT_STANDARD_TARGET) == 0) &&
 410                                     t->verdict < -NF_MAX_VERDICT - 1) {
 411                                         duprintf("mark_source_chains: bad "
 412                                                 "negative verdict (%i)\n",
 413                                                                 t->verdict);
 414                                         return 0;
 415                                 }
 416
 417                                 /* Return: backtrack through the last
 418                                  * big jump.
 419                                  */
 420                                 do {
 421                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 422                                         oldpos = pos;
 423                                         pos = e->counters.pcnt;
 424                                         e->counters.pcnt = 0;
 425
 426                                         /* We're at the start. */
 427                                         if (pos == oldpos)
 428                                                 goto next;
 429
 430                                         e = (struct arpt_entry *)
 431                                                 (entry0 + pos);
 432                                 } while (oldpos == pos + e->next_offset);
 433
 434                                 /* Move along one */
 435                                 size = e->next_offset;
 436                                 e = (struct arpt_entry *)
 437                                         (entry0 + pos + size);
 438                                 e->counters.pcnt = pos;
 439                                 pos += size;
 440                         } else {
 441                                 int newpos = t->verdict;
 442
 443                                 if (strcmp(t->target.u.user.name,
 444                                            ARPT_STANDARD_TARGET) == 0 &&
 445                                     newpos >= 0) {
 446                                         if (newpos > newinfo->size -
 447                                                 sizeof(struct arpt_entry)) {
 448                                                 duprintf("mark_source_chains: "
 449                                                         "bad verdict (%i)\n",
 450                                                                 newpos);
 451                                                 return 0;
 452                                         }
 453
 454                                         /* This a jump; chase it. */
 455                                         duprintf("Jump rule %u -> %u\n",
 456                                                  pos, newpos);
 457                                 } else {
 458                                         /* ... this is a fallthru */
 459                                         newpos = pos + e->next_offset;
 460                                 }
 461                                 e = (struct arpt_entry *)
 462                                         (entry0 + newpos);
 463                                 e->counters.pcnt = pos;
 464                                 pos = newpos;
 465                         }
 466                 }
 467                 next:
 468                 duprintf("Finished chain %u\n", hook);
 469         }
 470         return 1;
 471 }
 472
 473 static inline int check_entry(const struct arpt_entry *e, const char *name)
 474 {
 475         const struct arpt_entry_target *t;
 476
 477         if (!arp_checkentry(&e->arp)) {
 478                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 479                 return -EINVAL;
 480         }
 481
 482         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 483                 return -EINVAL;
 484
 485         t = arpt_get_target_c(e);
 486         if (e->target_offset + t->u.target_size > e->next_offset)
 487                 return -EINVAL;
 488
 489         return 0;
 490 }
 491
 492 static inline int check_target(struct arpt_entry *e, const char *name)
 493 {
 494         struct arpt_entry_target *t = arpt_get_target(e);
 495         int ret;
 496         struct xt_tgchk_param par = {
 497                 .table     = name,
 498                 .entryinfo = e,
 499                 .target    = t->u.kernel.target,
 500                 .targinfo  = t->data,
 501                 .hook_mask = e->comefrom,
 502                 .family    = NFPROTO_ARP,
 503         };
 504
 505         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 506         if (ret < 0) {
 507                 duprintf("arp_tables: check failed for `%s'.\n",
 508                          t->u.kernel.target->name);
 509                 return ret;
 510         }
 511         return 0;
 512 }
 513
 514 static inline int
 515 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 516 {
 517         struct arpt_entry_target *t;
 518         struct xt_target *target;
 519         int ret;
 520
 521         ret = check_entry(e, name);
 522         if (ret)
 523                 return ret;
 524
 525         t = arpt_get_target(e);
 526         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 527                                                         t->u.user.name,
 528                                                         t->u.user.revision),
 529                                          "arpt_%s", t->u.user.name);
 530         if (IS_ERR(target) || !target) {
 531                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 532                 ret = target ? PTR_ERR(target) : -ENOENT;
 533                 goto out;
 534         }
 535         t->u.kernel.target = target;
 536
 537         ret = check_target(e, name);
 538         if (ret)
 539                 goto err;
 540         return 0;
 541 err:
 542         module_put(t->u.kernel.target->me);
 543 out:
 544         return ret;
 545 }
 546
 547 static bool check_underflow(const struct arpt_entry *e)
 548 {
 549         const struct arpt_entry_target *t;
 550         unsigned int verdict;
 551
 552         if (!unconditional(&e->arp))
 553                 return false;
 554         t = arpt_get_target_c(e);
 555         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 556                 return false;
 557         verdict = ((struct arpt_standard_target *)t)->verdict;
 558         verdict = -verdict - 1;
 559         return verdict == NF_DROP || verdict == NF_ACCEPT;
 560 }
 561
 562 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 563                                              struct xt_table_info *newinfo,
 564                                              const unsigned char *base,
 565                                              const unsigned char *limit,
 566                                              const unsigned int *hook_entries,
 567                                              const unsigned int *underflows,
 568                                              unsigned int valid_hooks)
 569 {
 570         unsigned int h;
 571
 572         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 573             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 574                 duprintf("Bad offset %p\n", e);
 575                 return -EINVAL;
 576         }
 577
 578         if (e->next_offset
 579             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 580                 duprintf("checking: element %p size %u\n",
 581                          e, e->next_offset);
 582                 return -EINVAL;
 583         }
 584
 585         /* Check hooks & underflows */
 586         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 587                 if (!(valid_hooks & (1 << h)))
 588                         continue;
 589                 if ((unsigned char *)e - base == hook_entries[h])
 590                         newinfo->hook_entry[h] = hook_entries[h];
 591                 if ((unsigned char *)e - base == underflows[h]) {
 592                         if (!check_underflow(e)) {
 593                                 pr_err("Underflows must be unconditional and "
 594                                        "use the STANDARD target with "
 595                                        "ACCEPT/DROP\n");
 596                                 return -EINVAL;
 597                         }
 598                         newinfo->underflow[h] = underflows[h];
 599                 }
 600         }
 601
 602         /* Clear counters and comefrom */
 603         e->counters = ((struct xt_counters) { 0, 0 });
 604         e->comefrom = 0;
 605         return 0;
 606 }
 607
 608 static inline void cleanup_entry(struct arpt_entry *e)
 609 {
 610         struct xt_tgdtor_param par;
 611         struct arpt_entry_target *t;
 612
 613         t = arpt_get_target(e);
 614         par.target   = t->u.kernel.target;
 615         par.targinfo = t->data;
 616         par.family   = NFPROTO_ARP;
 617         if (par.target->destroy != NULL)
 618                 par.target->destroy(&par);
 619         module_put(par.target->me);
 620 }
 621
 622 /* Checks and translates the user-supplied table segment (held in
 623  * newinfo).
 624  */
 625 static int translate_table(const char *name,
 626                            unsigned int valid_hooks,
 627                            struct xt_table_info *newinfo,
 628                            void *entry0,
 629                            unsigned int size,
 630                            unsigned int number,
 631                            const unsigned int *hook_entries,
 632                            const unsigned int *underflows)
 633 {
 634         struct arpt_entry *iter;
 635         unsigned int i;
 636         int ret = 0;
 637
 638         newinfo->size = size;
 639         newinfo->number = number;
 640
 641         /* Init all hooks to impossible value. */
 642         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 643                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 644                 newinfo->underflow[i] = 0xFFFFFFFF;
 645         }
 646
 647         duprintf("translate_table: size %u\n", newinfo->size);
 648         i = 0;
 649
 650         /* Walk through entries, checking offsets. */
 651         xt_entry_foreach(iter, entry0, newinfo->size) {
 652                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 653                       entry0 + size, hook_entries, underflows, valid_hooks);
 654                 if (ret != 0)
 655                         break;
 656                 ++i;
 657         }
 658         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 659         if (ret != 0)
 660                 return ret;
 661
 662         if (i != number) {
 663                 duprintf("translate_table: %u not %u entries\n",
 664                          i, number);
 665                 return -EINVAL;
 666         }
 667
 668         /* Check hooks all assigned */
 669         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 670                 /* Only hooks which are valid */
 671                 if (!(valid_hooks & (1 << i)))
 672                         continue;
 673                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 674                         duprintf("Invalid hook entry %u %u\n",
 675                                  i, hook_entries[i]);
 676                         return -EINVAL;
 677                 }
 678                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 679                         duprintf("Invalid underflow %u %u\n",
 680                                  i, underflows[i]);
 681                         return -EINVAL;
 682                 }
 683         }
 684
 685         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 686                 duprintf("Looping hook\n");
 687                 return -ELOOP;
 688         }
 689
 690         /* Finally, each sanity check must pass */
 691         i = 0;
 692         xt_entry_foreach(iter, entry0, newinfo->size) {
 693                 ret = find_check_entry(iter, name, size);
 694                 if (ret != 0)
 695                         break;
 696                 ++i;
 697         }
 698
 699         if (ret != 0) {
 700                 xt_entry_foreach(iter, entry0, newinfo->size) {
 701                         if (i-- == 0)
 702                                 break;
 703                         cleanup_entry(iter);
 704                 }
 705                 return ret;
 706         }
 707
 708         /* And one copy for every other CPU */
 709         for_each_possible_cpu(i) {
 710                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 711                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 712         }
 713
 714         return ret;
 715 }
 716
 717 static void get_counters(const struct xt_table_info *t,
 718                          struct xt_counters counters[])
 719 {
 720         struct arpt_entry *iter;
 721         unsigned int cpu;
 722         unsigned int i;
 723         unsigned int curcpu;
 724
 725         /* Instead of clearing (by a previous call to memset())
 726          * the counters and using adds, we set the counters
 727          * with data used by 'current' CPU
 728          *
 729          * Bottom half has to be disabled to prevent deadlock
 730          * if new softirq were to run and call ipt_do_table
 731          */
 732         local_bh_disable();
 733         curcpu = smp_processor_id();
 734
 735         i = 0;
 736         xt_entry_foreach(iter, t->entries[curcpu], t->size) {
 737                 SET_COUNTER(counters[i], iter->counters.bcnt,
 738                         iter->counters.pcnt);
 739                 ++i;
 740         }
 741
 742         for_each_possible_cpu(cpu) {
 743                 if (cpu == curcpu)
 744                         continue;
 745                 i = 0;
 746                 xt_info_wrlock(cpu);
 747                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 748                         ADD_COUNTER(counters[i], iter->counters.bcnt,
 749                                 iter->counters.pcnt);
 750                         ++i;
 751                 }
 752                 xt_info_wrunlock(cpu);
 753         }
 754         local_bh_enable();
 755 }
 756
 757 static struct xt_counters *alloc_counters(const struct xt_table *table)
 758 {
 759         unsigned int countersize;
 760         struct xt_counters *counters;
 761         const struct xt_table_info *private = table->private;
 762
 763         /* We need atomic snapshot of counters: rest doesn't change
 764          * (other than comefrom, which userspace doesn't care
 765          * about).
 766          */
 767         countersize = sizeof(struct xt_counters) * private->number;
 768         counters = vmalloc_node(countersize, numa_node_id());
 769
 770         if (counters == NULL)
 771                 return ERR_PTR(-ENOMEM);
 772
 773         get_counters(private, counters);
 774
 775         return counters;
 776 }
 777
 778 static int copy_entries_to_user(unsigned int total_size,
 779                                 const struct xt_table *table,
 780                                 void __user *userptr)
 781 {
 782         unsigned int off, num;
 783         const struct arpt_entry *e;
 784         struct xt_counters *counters;
 785         struct xt_table_info *private = table->private;
 786         int ret = 0;
 787         void *loc_cpu_entry;
 788
 789         counters = alloc_counters(table);
 790         if (IS_ERR(counters))
 791                 return PTR_ERR(counters);
 792
 793         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 794         /* ... then copy entire thing ... */
 795         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 796                 ret = -EFAULT;
 797                 goto free_counters;
 798         }
 799
 800         /* FIXME: use iterator macros --RR */
 801         /* ... then go back and fix counters and names */
 802         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 803                 const struct arpt_entry_target *t;
 804
 805                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 806                 if (copy_to_user(userptr + off
 807                                  + offsetof(struct arpt_entry, counters),
 808                                  &counters[num],
 809                                  sizeof(counters[num])) != 0) {
 810                         ret = -EFAULT;
 811                         goto free_counters;
 812                 }
 813
 814                 t = arpt_get_target_c(e);
 815                 if (copy_to_user(userptr + off + e->target_offset
 816                                  + offsetof(struct arpt_entry_target,
 817                                             u.user.name),
 818                                  t->u.kernel.target->name,
 819                                  strlen(t->u.kernel.target->name)+1) != 0) {
 820                         ret = -EFAULT;
 821                         goto free_counters;
 822                 }
 823         }
 824
 825  free_counters:
 826         vfree(counters);
 827         return ret;
 828 }
 829
 830 #ifdef CONFIG_COMPAT
 831 static void compat_standard_from_user(void *dst, const void *src)
 832 {
 833         int v = *(compat_int_t *)src;
 834
 835         if (v > 0)
 836                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 837         memcpy(dst, &v, sizeof(v));
 838 }
 839
 840 static int compat_standard_to_user(void __user *dst, const void *src)
 841 {
 842         compat_int_t cv = *(int *)src;
 843
 844         if (cv > 0)
 845                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 846         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 847 }
 848
 849 static int compat_calc_entry(const struct arpt_entry *e,
 850                              const struct xt_table_info *info,
 851                              const void *base, struct xt_table_info *newinfo)
 852 {
 853         const struct arpt_entry_target *t;
 854         unsigned int entry_offset;
 855         int off, i, ret;
 856
 857         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 858         entry_offset = (void *)e - base;
 859
 860         t = arpt_get_target_c(e);
 861         off += xt_compat_target_offset(t->u.kernel.target);
 862         newinfo->size -= off;
 863         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 864         if (ret)
 865                 return ret;
 866
 867         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 868                 if (info->hook_entry[i] &&
 869                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 870                         newinfo->hook_entry[i] -= off;
 871                 if (info->underflow[i] &&
 872                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 873                         newinfo->underflow[i] -= off;
 874         }
 875         return 0;
 876 }
 877
 878 static int compat_table_info(const struct xt_table_info *info,
 879                              struct xt_table_info *newinfo)
 880 {
 881         struct arpt_entry *iter;
 882         void *loc_cpu_entry;
 883         int ret;
 884
 885         if (!newinfo || !info)
 886                 return -EINVAL;
 887
 888         /* we dont care about newinfo->entries[] */
 889         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 890         newinfo->initial_entries = 0;
 891         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 892         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 893                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 894                 if (ret != 0)
 895                         return ret;
 896         }
 897         return 0;
 898 }
 899 #endif
 900
 901 static int get_info(struct net *net, void __user *user,
 902                     const int *len, int compat)
 903 {
 904         char name[ARPT_TABLE_MAXNAMELEN];
 905         struct xt_table *t;
 906         int ret;
 907
 908         if (*len != sizeof(struct arpt_getinfo)) {
 909                 duprintf("length %u != %Zu\n", *len,
 910                          sizeof(struct arpt_getinfo));
 911                 return -EINVAL;
 912         }
 913
 914         if (copy_from_user(name, user, sizeof(name)) != 0)
 915                 return -EFAULT;
 916
 917         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 918 #ifdef CONFIG_COMPAT
 919         if (compat)
 920                 xt_compat_lock(NFPROTO_ARP);
 921 #endif
 922         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 923                                     "arptable_%s", name);
 924         if (t && !IS_ERR(t)) {
 925                 struct arpt_getinfo info;
 926                 const struct xt_table_info *private = t->private;
 927 #ifdef CONFIG_COMPAT
 928                 struct xt_table_info tmp;
 929
 930                 if (compat) {
 931                         ret = compat_table_info(private, &tmp);
 932                         xt_compat_flush_offsets(NFPROTO_ARP);
 933                         private = &tmp;
 934                 }
 935 #endif
 936                 info.valid_hooks = t->valid_hooks;
 937                 memcpy(info.hook_entry, private->hook_entry,
 938                        sizeof(info.hook_entry));
 939                 memcpy(info.underflow, private->underflow,
 940                        sizeof(info.underflow));
 941                 info.num_entries = private->number;
 942                 info.size = private->size;
 943                 strcpy(info.name, name);
 944
 945                 if (copy_to_user(user, &info, *len) != 0)
 946                         ret = -EFAULT;
 947                 else
 948                         ret = 0;
 949                 xt_table_unlock(t);
 950                 module_put(t->me);
 951         } else
 952                 ret = t ? PTR_ERR(t) : -ENOENT;
 953 #ifdef CONFIG_COMPAT
 954         if (compat)
 955                 xt_compat_unlock(NFPROTO_ARP);
 956 #endif
 957         return ret;
 958 }
 959
 960 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 961                        const int *len)
 962 {
 963         int ret;
 964         struct arpt_get_entries get;
 965         struct xt_table *t;
 966
 967         if (*len < sizeof(get)) {
 968                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 969                 return -EINVAL;
 970         }
 971         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 972                 return -EFAULT;
 973         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 974                 duprintf("get_entries: %u != %Zu\n", *len,
 975                          sizeof(struct arpt_get_entries) + get.size);
 976                 return -EINVAL;
 977         }
 978
 979         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 980         if (t && !IS_ERR(t)) {
 981                 const struct xt_table_info *private = t->private;
 982
 983                 duprintf("t->private->number = %u\n",
 984                          private->number);
 985                 if (get.size == private->size)
 986                         ret = copy_entries_to_user(private->size,
 987                                                    t, uptr->entrytable);
 988                 else {
 989                         duprintf("get_entries: I've got %u not %u!\n",
 990                                  private->size, get.size);
 991                         ret = -EAGAIN;
 992                 }
 993                 module_put(t->me);
 994                 xt_table_unlock(t);
 995         } else
 996                 ret = t ? PTR_ERR(t) : -ENOENT;
 997
 998         return ret;
 999 }
1000
1001 static int __do_replace(struct net *net, const char *name,
1002                         unsigned int valid_hooks,
1003                         struct xt_table_info *newinfo,
1004                         unsigned int num_counters,
1005                         void __user *counters_ptr)
1006 {
1007         int ret;
1008         struct xt_table *t;
1009         struct xt_table_info *oldinfo;
1010         struct xt_counters *counters;
1011         void *loc_cpu_old_entry;
1012         struct arpt_entry *iter;
1013
1014         ret = 0;
1015         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
1016                                 numa_node_id());
1017         if (!counters) {
1018                 ret = -ENOMEM;
1019                 goto out;
1020         }
1021
1022         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1023                                     "arptable_%s", name);
1024         if (!t || IS_ERR(t)) {
1025                 ret = t ? PTR_ERR(t) : -ENOENT;
1026                 goto free_newinfo_counters_untrans;
1027         }
1028
1029         /* You lied! */
1030         if (valid_hooks != t->valid_hooks) {
1031                 duprintf("Valid hook crap: %08X vs %08X\n",
1032                          valid_hooks, t->valid_hooks);
1033                 ret = -EINVAL;
1034                 goto put_module;
1035         }
1036
1037         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1038         if (!oldinfo)
1039                 goto put_module;
1040
1041         /* Update module usage count based on number of rules */
1042         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1043                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1044         if ((oldinfo->number > oldinfo->initial_entries) ||
1045             (newinfo->number <= oldinfo->initial_entries))
1046                 module_put(t->me);
1047         if ((oldinfo->number > oldinfo->initial_entries) &&
1048             (newinfo->number <= oldinfo->initial_entries))
1049                 module_put(t->me);
1050
1051         /* Get the old counters, and synchronize with replace */
1052         get_counters(oldinfo, counters);
1053
1054         /* Decrease module usage counts and free resource */
1055         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1056         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1057                 cleanup_entry(iter);
1058
1059         xt_free_table_info(oldinfo);
1060         if (copy_to_user(counters_ptr, counters,
1061                          sizeof(struct xt_counters) * num_counters) != 0)
1062                 ret = -EFAULT;
1063         vfree(counters);
1064         xt_table_unlock(t);
1065         return ret;
1066
1067  put_module:
1068         module_put(t->me);
1069         xt_table_unlock(t);
1070  free_newinfo_counters_untrans:
1071         vfree(counters);
1072  out:
1073         return ret;
1074 }
1075
1076 static int do_replace(struct net *net, const void __user *user,
1077                       unsigned int len)
1078 {
1079         int ret;
1080         struct arpt_replace tmp;
1081         struct xt_table_info *newinfo;
1082         void *loc_cpu_entry;
1083         struct arpt_entry *iter;
1084
1085         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1086                 return -EFAULT;
1087
1088         /* overflow check */
1089         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1090                 return -ENOMEM;
1091
1092         newinfo = xt_alloc_table_info(tmp.size);
1093         if (!newinfo)
1094                 return -ENOMEM;
1095
1096         /* choose the copy that is on our node/cpu */
1097         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1098         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1099                            tmp.size) != 0) {
1100                 ret = -EFAULT;
1101                 goto free_newinfo;
1102         }
1103
1104         ret = translate_table(tmp.name, tmp.valid_hooks,
1105                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1106                               tmp.hook_entry, tmp.underflow);
1107         if (ret != 0)
1108                 goto free_newinfo;
1109
1110         duprintf("arp_tables: Translated table\n");
1111
1112         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1113                            tmp.num_counters, tmp.counters);
1114         if (ret)
1115                 goto free_newinfo_untrans;
1116         return 0;
1117
1118  free_newinfo_untrans:
1119         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1120                 cleanup_entry(iter);
1121  free_newinfo:
1122         xt_free_table_info(newinfo);
1123         return ret;
1124 }
1125
1126 static int do_add_counters(struct net *net, const void __user *user,
1127                            unsigned int len, int compat)
1128 {
1129         unsigned int i, curcpu;
1130         struct xt_counters_info tmp;
1131         struct xt_counters *paddc;
1132         unsigned int num_counters;
1133         const char *name;
1134         int size;
1135         void *ptmp;
1136         struct xt_table *t;
1137         const struct xt_table_info *private;
1138         int ret = 0;
1139         void *loc_cpu_entry;
1140         struct arpt_entry *iter;
1141 #ifdef CONFIG_COMPAT
1142         struct compat_xt_counters_info compat_tmp;
1143
1144         if (compat) {
1145                 ptmp = &compat_tmp;
1146                 size = sizeof(struct compat_xt_counters_info);
1147         } else
1148 #endif
1149         {
1150                 ptmp = &tmp;
1151                 size = sizeof(struct xt_counters_info);
1152         }
1153
1154         if (copy_from_user(ptmp, user, size) != 0)
1155                 return -EFAULT;
1156
1157 #ifdef CONFIG_COMPAT
1158         if (compat) {
1159                 num_counters = compat_tmp.num_counters;
1160                 name = compat_tmp.name;
1161         } else
1162 #endif
1163         {
1164                 num_counters = tmp.num_counters;
1165                 name = tmp.name;
1166         }
1167
1168         if (len != size + num_counters * sizeof(struct xt_counters))
1169                 return -EINVAL;
1170
1171         paddc = vmalloc_node(len - size, numa_node_id());
1172         if (!paddc)
1173                 return -ENOMEM;
1174
1175         if (copy_from_user(paddc, user + size, len - size) != 0) {
1176                 ret = -EFAULT;
1177                 goto free;
1178         }
1179
1180         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1181         if (!t || IS_ERR(t)) {
1182                 ret = t ? PTR_ERR(t) : -ENOENT;
1183                 goto free;
1184         }
1185
1186         local_bh_disable();
1187         private = t->private;
1188         if (private->number != num_counters) {
1189                 ret = -EINVAL;
1190                 goto unlock_up_free;
1191         }
1192
1193         i = 0;
1194         /* Choose the copy that is on our node */
1195         curcpu = smp_processor_id();
1196         loc_cpu_entry = private->entries[curcpu];
1197         xt_info_wrlock(curcpu);
1198         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1199                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1200                 ++i;
1201         }
1202         xt_info_wrunlock(curcpu);
1203  unlock_up_free:
1204         local_bh_enable();
1205         xt_table_unlock(t);
1206         module_put(t->me);
1207  free:
1208         vfree(paddc);
1209
1210         return ret;
1211 }
1212
1213 #ifdef CONFIG_COMPAT
1214 static inline void compat_release_entry(struct compat_arpt_entry *e)
1215 {
1216         struct arpt_entry_target *t;
1217
1218         t = compat_arpt_get_target(e);
1219         module_put(t->u.kernel.target->me);
1220 }
1221
1222 static inline int
1223 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1224                                   struct xt_table_info *newinfo,
1225                                   unsigned int *size,
1226                                   const unsigned char *base,
1227                                   const unsigned char *limit,
1228                                   const unsigned int *hook_entries,
1229                                   const unsigned int *underflows,
1230                                   const char *name)
1231 {
1232         struct arpt_entry_target *t;
1233         struct xt_target *target;
1234         unsigned int entry_offset;
1235         int ret, off, h;
1236
1237         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1238         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1239             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1240                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1241                 return -EINVAL;
1242         }
1243
1244         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1245                              sizeof(struct compat_xt_entry_target)) {
1246                 duprintf("checking: element %p size %u\n",
1247                          e, e->next_offset);
1248                 return -EINVAL;
1249         }
1250
1251         /* For purposes of check_entry casting the compat entry is fine */
1252         ret = check_entry((struct arpt_entry *)e, name);
1253         if (ret)
1254                 return ret;
1255
1256         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1257         entry_offset = (void *)e - (void *)base;
1258
1259         t = compat_arpt_get_target(e);
1260         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1261                                                         t->u.user.name,
1262                                                         t->u.user.revision),
1263                                          "arpt_%s", t->u.user.name);
1264         if (IS_ERR(target) || !target) {
1265                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1266                          t->u.user.name);
1267                 ret = target ? PTR_ERR(target) : -ENOENT;
1268                 goto out;
1269         }
1270         t->u.kernel.target = target;
1271
1272         off += xt_compat_target_offset(target);
1273         *size += off;
1274         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1275         if (ret)
1276                 goto release_target;
1277
1278         /* Check hooks & underflows */
1279         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1280                 if ((unsigned char *)e - base == hook_entries[h])
1281                         newinfo->hook_entry[h] = hook_entries[h];
1282                 if ((unsigned char *)e - base == underflows[h])
1283                         newinfo->underflow[h] = underflows[h];
1284         }
1285
1286         /* Clear counters and comefrom */
1287         memset(&e->counters, 0, sizeof(e->counters));
1288         e->comefrom = 0;
1289         return 0;
1290
1291 release_target:
1292         module_put(t->u.kernel.target->me);
1293 out:
1294         return ret;
1295 }
1296
1297 static int
1298 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1299                             unsigned int *size, const char *name,
1300                             struct xt_table_info *newinfo, unsigned char *base)
1301 {
1302         struct arpt_entry_target *t;
1303         struct xt_target *target;
1304         struct arpt_entry *de;
1305         unsigned int origsize;
1306         int ret, h;
1307
1308         ret = 0;
1309         origsize = *size;
1310         de = (struct arpt_entry *)*dstptr;
1311         memcpy(de, e, sizeof(struct arpt_entry));
1312         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1313
1314         *dstptr += sizeof(struct arpt_entry);
1315         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1316
1317         de->target_offset = e->target_offset - (origsize - *size);
1318         t = compat_arpt_get_target(e);
1319         target = t->u.kernel.target;
1320         xt_compat_target_from_user(t, dstptr, size);
1321
1322         de->next_offset = e->next_offset - (origsize - *size);
1323         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1324                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1325                         newinfo->hook_entry[h] -= origsize - *size;
1326                 if ((unsigned char *)de - base < newinfo->underflow[h])
1327                         newinfo->underflow[h] -= origsize - *size;
1328         }
1329         return ret;
1330 }
1331
1332 static int translate_compat_table(const char *name,
1333                                   unsigned int valid_hooks,
1334                                   struct xt_table_info **pinfo,
1335                                   void **pentry0,
1336                                   unsigned int total_size,
1337                                   unsigned int number,
1338                                   unsigned int *hook_entries,
1339                                   unsigned int *underflows)
1340 {
1341         unsigned int i, j;
1342         struct xt_table_info *newinfo, *info;
1343         void *pos, *entry0, *entry1;
1344         struct compat_arpt_entry *iter0;
1345         struct arpt_entry *iter1;
1346         unsigned int size;
1347         int ret = 0;
1348
1349         info = *pinfo;
1350         entry0 = *pentry0;
1351         size = total_size;
1352         info->number = number;
1353
1354         /* Init all hooks to impossible value. */
1355         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1356                 info->hook_entry[i] = 0xFFFFFFFF;
1357                 info->underflow[i] = 0xFFFFFFFF;
1358         }
1359
1360         duprintf("translate_compat_table: size %u\n", info->size);
1361         j = 0;
1362         xt_compat_lock(NFPROTO_ARP);
1363         /* Walk through entries, checking offsets. */
1364         xt_entry_foreach(iter0, entry0, total_size) {
1365                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1366                       entry0, entry0 + total_size, hook_entries, underflows,
1367                       name);
1368                 if (ret != 0)
1369                         goto out_unlock;
1370                 ++j;
1371         }
1372
1373         ret = -EINVAL;
1374         if (j != number) {
1375                 duprintf("translate_compat_table: %u not %u entries\n",
1376                          j, number);
1377                 goto out_unlock;
1378         }
1379
1380         /* Check hooks all assigned */
1381         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1382                 /* Only hooks which are valid */
1383                 if (!(valid_hooks & (1 << i)))
1384                         continue;
1385                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1386                         duprintf("Invalid hook entry %u %u\n",
1387                                  i, hook_entries[i]);
1388                         goto out_unlock;
1389                 }
1390                 if (info->underflow[i] == 0xFFFFFFFF) {
1391                         duprintf("Invalid underflow %u %u\n",
1392                                  i, underflows[i]);
1393                         goto out_unlock;
1394                 }
1395         }
1396
1397         ret = -ENOMEM;
1398         newinfo = xt_alloc_table_info(size);
1399         if (!newinfo)
1400                 goto out_unlock;
1401
1402         newinfo->number = number;
1403         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1404                 newinfo->hook_entry[i] = info->hook_entry[i];
1405                 newinfo->underflow[i] = info->underflow[i];
1406         }
1407         entry1 = newinfo->entries[raw_smp_processor_id()];
1408         pos = entry1;
1409         size = total_size;
1410         xt_entry_foreach(iter0, entry0, total_size) {
1411                 ret = compat_copy_entry_from_user(iter0, &pos,
1412                       &size, name, newinfo, entry1);
1413                 if (ret != 0)
1414                         break;
1415         }
1416         xt_compat_flush_offsets(NFPROTO_ARP);
1417         xt_compat_unlock(NFPROTO_ARP);
1418         if (ret)
1419                 goto free_newinfo;
1420
1421         ret = -ELOOP;
1422         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1423                 goto free_newinfo;
1424
1425         i = 0;
1426         xt_entry_foreach(iter1, entry1, newinfo->size) {
1427                 ret = check_target(iter1, name);
1428                 if (ret != 0)
1429                         break;
1430                 ++i;
1431         }
1432         if (ret) {
1433                 /*
1434                  * The first i matches need cleanup_entry (calls ->destroy)
1435                  * because they had called ->check already. The other j-i
1436                  * entries need only release.
1437                  */
1438                 int skip = i;
1439                 j -= i;
1440                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1441                         if (skip-- > 0)
1442                                 continue;
1443                         if (j-- == 0)
1444                                 break;
1445                         compat_release_entry(iter0);
1446                 }
1447                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1448                         if (i-- == 0)
1449                                 break;
1450                         cleanup_entry(iter1);
1451                 }
1452                 xt_free_table_info(newinfo);
1453                 return ret;
1454         }
1455
1456         /* And one copy for every other CPU */
1457         for_each_possible_cpu(i)
1458                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1459                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1460
1461         *pinfo = newinfo;
1462         *pentry0 = entry1;
1463         xt_free_table_info(info);
1464         return 0;
1465
1466 free_newinfo:
1467         xt_free_table_info(newinfo);
1468 out:
1469         xt_entry_foreach(iter0, entry0, total_size) {
1470                 if (j-- == 0)
1471                         break;
1472                 compat_release_entry(iter0);
1473         }
1474         return ret;
1475 out_unlock:
1476         xt_compat_flush_offsets(NFPROTO_ARP);
1477         xt_compat_unlock(NFPROTO_ARP);
1478         goto out;
1479 }
1480
1481 struct compat_arpt_replace {
1482         char                            name[ARPT_TABLE_MAXNAMELEN];
1483         u32                             valid_hooks;
1484         u32                             num_entries;
1485         u32                             size;
1486         u32                             hook_entry[NF_ARP_NUMHOOKS];
1487         u32                             underflow[NF_ARP_NUMHOOKS];
1488         u32                             num_counters;
1489         compat_uptr_t                   counters;
1490         struct compat_arpt_entry        entries[0];
1491 };
1492
1493 static int compat_do_replace(struct net *net, void __user *user,
1494                              unsigned int len)
1495 {
1496         int ret;
1497         struct compat_arpt_replace tmp;
1498         struct xt_table_info *newinfo;
1499         void *loc_cpu_entry;
1500         struct arpt_entry *iter;
1501
1502         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1503                 return -EFAULT;
1504
1505         /* overflow check */
1506         if (tmp.size >= INT_MAX / num_possible_cpus())
1507                 return -ENOMEM;
1508         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1509                 return -ENOMEM;
1510
1511         newinfo = xt_alloc_table_info(tmp.size);
1512         if (!newinfo)
1513                 return -ENOMEM;
1514
1515         /* choose the copy that is on our node/cpu */
1516         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1517         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1518                 ret = -EFAULT;
1519                 goto free_newinfo;
1520         }
1521
1522         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1523                                      &newinfo, &loc_cpu_entry, tmp.size,
1524                                      tmp.num_entries, tmp.hook_entry,
1525                                      tmp.underflow);
1526         if (ret != 0)
1527                 goto free_newinfo;
1528
1529         duprintf("compat_do_replace: Translated table\n");
1530
1531         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1532                            tmp.num_counters, compat_ptr(tmp.counters));
1533         if (ret)
1534                 goto free_newinfo_untrans;
1535         return 0;
1536
1537  free_newinfo_untrans:
1538         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1539                 cleanup_entry(iter);
1540  free_newinfo:
1541         xt_free_table_info(newinfo);
1542         return ret;
1543 }
1544
1545 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1546                                   unsigned int len)
1547 {
1548         int ret;
1549
1550         if (!capable(CAP_NET_ADMIN))
1551                 return -EPERM;
1552
1553         switch (cmd) {
1554         case ARPT_SO_SET_REPLACE:
1555                 ret = compat_do_replace(sock_net(sk), user, len);
1556                 break;
1557
1558         case ARPT_SO_SET_ADD_COUNTERS:
1559                 ret = do_add_counters(sock_net(sk), user, len, 1);
1560                 break;
1561
1562         default:
1563                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1564                 ret = -EINVAL;
1565         }
1566
1567         return ret;
1568 }
1569
1570 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1571                                      compat_uint_t *size,
1572                                      struct xt_counters *counters,
1573                                      unsigned int i)
1574 {
1575         struct arpt_entry_target *t;
1576         struct compat_arpt_entry __user *ce;
1577         u_int16_t target_offset, next_offset;
1578         compat_uint_t origsize;
1579         int ret;
1580
1581         origsize = *size;
1582         ce = (struct compat_arpt_entry __user *)*dstptr;
1583         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1584             copy_to_user(&ce->counters, &counters[i],
1585             sizeof(counters[i])) != 0)
1586                 return -EFAULT;
1587
1588         *dstptr += sizeof(struct compat_arpt_entry);
1589         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1590
1591         target_offset = e->target_offset - (origsize - *size);
1592
1593         t = arpt_get_target(e);
1594         ret = xt_compat_target_to_user(t, dstptr, size);
1595         if (ret)
1596                 return ret;
1597         next_offset = e->next_offset - (origsize - *size);
1598         if (put_user(target_offset, &ce->target_offset) != 0 ||
1599             put_user(next_offset, &ce->next_offset) != 0)
1600                 return -EFAULT;
1601         return 0;
1602 }
1603
1604 static int compat_copy_entries_to_user(unsigned int total_size,
1605                                        struct xt_table *table,
1606                                        void __user *userptr)
1607 {
1608         struct xt_counters *counters;
1609         const struct xt_table_info *private = table->private;
1610         void __user *pos;
1611         unsigned int size;
1612         int ret = 0;
1613         void *loc_cpu_entry;
1614         unsigned int i = 0;
1615         struct arpt_entry *iter;
1616
1617         counters = alloc_counters(table);
1618         if (IS_ERR(counters))
1619                 return PTR_ERR(counters);
1620
1621         /* choose the copy on our node/cpu */
1622         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1623         pos = userptr;
1624         size = total_size;
1625         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1626                 ret = compat_copy_entry_to_user(iter, &pos,
1627                       &size, counters, i++);
1628                 if (ret != 0)
1629                         break;
1630         }
1631         vfree(counters);
1632         return ret;
1633 }
1634
1635 struct compat_arpt_get_entries {
1636         char name[ARPT_TABLE_MAXNAMELEN];
1637         compat_uint_t size;
1638         struct compat_arpt_entry entrytable[0];
1639 };
1640
1641 static int compat_get_entries(struct net *net,
1642                               struct compat_arpt_get_entries __user *uptr,
1643                               int *len)
1644 {
1645         int ret;
1646         struct compat_arpt_get_entries get;
1647         struct xt_table *t;
1648
1649         if (*len < sizeof(get)) {
1650                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1651                 return -EINVAL;
1652         }
1653         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1654                 return -EFAULT;
1655         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1656                 duprintf("compat_get_entries: %u != %zu\n",
1657                          *len, sizeof(get) + get.size);
1658                 return -EINVAL;
1659         }
1660
1661         xt_compat_lock(NFPROTO_ARP);
1662         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1663         if (t && !IS_ERR(t)) {
1664                 const struct xt_table_info *private = t->private;
1665                 struct xt_table_info info;
1666
1667                 duprintf("t->private->number = %u\n", private->number);
1668                 ret = compat_table_info(private, &info);
1669                 if (!ret && get.size == info.size) {
1670                         ret = compat_copy_entries_to_user(private->size,
1671                                                           t, uptr->entrytable);
1672                 } else if (!ret) {
1673                         duprintf("compat_get_entries: I've got %u not %u!\n",
1674                                  private->size, get.size);
1675                         ret = -EAGAIN;
1676                 }
1677                 xt_compat_flush_offsets(NFPROTO_ARP);
1678                 module_put(t->me);
1679                 xt_table_unlock(t);
1680         } else
1681                 ret = t ? PTR_ERR(t) : -ENOENT;
1682
1683         xt_compat_unlock(NFPROTO_ARP);
1684         return ret;
1685 }
1686
1687 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1688
1689 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1690                                   int *len)
1691 {
1692         int ret;
1693
1694         if (!capable(CAP_NET_ADMIN))
1695                 return -EPERM;
1696
1697         switch (cmd) {
1698         case ARPT_SO_GET_INFO:
1699                 ret = get_info(sock_net(sk), user, len, 1);
1700                 break;
1701         case ARPT_SO_GET_ENTRIES:
1702                 ret = compat_get_entries(sock_net(sk), user, len);
1703                 break;
1704         default:
1705                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1706         }
1707         return ret;
1708 }
1709 #endif
1710
1711 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1712 {
1713         int ret;
1714
1715         if (!capable(CAP_NET_ADMIN))
1716                 return -EPERM;
1717
1718         switch (cmd) {
1719         case ARPT_SO_SET_REPLACE:
1720                 ret = do_replace(sock_net(sk), user, len);
1721                 break;
1722
1723         case ARPT_SO_SET_ADD_COUNTERS:
1724                 ret = do_add_counters(sock_net(sk), user, len, 0);
1725                 break;
1726
1727         default:
1728                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1729                 ret = -EINVAL;
1730         }
1731
1732         return ret;
1733 }
1734
1735 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1736 {
1737         int ret;
1738
1739         if (!capable(CAP_NET_ADMIN))
1740                 return -EPERM;
1741
1742         switch (cmd) {
1743         case ARPT_SO_GET_INFO:
1744                 ret = get_info(sock_net(sk), user, len, 0);
1745                 break;
1746
1747         case ARPT_SO_GET_ENTRIES:
1748                 ret = get_entries(sock_net(sk), user, len);
1749                 break;
1750
1751         case ARPT_SO_GET_REVISION_TARGET: {
1752                 struct xt_get_revision rev;
1753
1754                 if (*len != sizeof(rev)) {
1755                         ret = -EINVAL;
1756                         break;
1757                 }
1758                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1759                         ret = -EFAULT;
1760                         break;
1761                 }
1762
1763                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1764                                                          rev.revision, 1, &ret),
1765                                         "arpt_%s", rev.name);
1766                 break;
1767         }
1768
1769         default:
1770                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1771                 ret = -EINVAL;
1772         }
1773
1774         return ret;
1775 }
1776
1777 struct xt_table *arpt_register_table(struct net *net,
1778                                      const struct xt_table *table,
1779                                      const struct arpt_replace *repl)
1780 {
1781         int ret;
1782         struct xt_table_info *newinfo;
1783         struct xt_table_info bootstrap
1784                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1785         void *loc_cpu_entry;
1786         struct xt_table *new_table;
1787
1788         newinfo = xt_alloc_table_info(repl->size);
1789         if (!newinfo) {
1790                 ret = -ENOMEM;
1791                 goto out;
1792         }
1793
1794         /* choose the copy on our node/cpu */
1795         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1796         memcpy(loc_cpu_entry, repl->entries, repl->size);
1797
1798         ret = translate_table(table->name, table->valid_hooks,
1799                               newinfo, loc_cpu_entry, repl->size,
1800                               repl->num_entries,
1801                               repl->hook_entry,
1802                               repl->underflow);
1803
1804         duprintf("arpt_register_table: translate table gives %d\n", ret);
1805         if (ret != 0)
1806                 goto out_free;
1807
1808         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1809         if (IS_ERR(new_table)) {
1810                 ret = PTR_ERR(new_table);
1811                 goto out_free;
1812         }
1813         return new_table;
1814
1815 out_free:
1816         xt_free_table_info(newinfo);
1817 out:
1818         return ERR_PTR(ret);
1819 }
1820
1821 void arpt_unregister_table(struct xt_table *table)
1822 {
1823         struct xt_table_info *private;
1824         void *loc_cpu_entry;
1825         struct module *table_owner = table->me;
1826         struct arpt_entry *iter;
1827
1828         private = xt_unregister_table(table);
1829
1830         /* Decrease module usage counts and free resources */
1831         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1832         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1833                 cleanup_entry(iter);
1834         if (private->number > private->initial_entries)
1835                 module_put(table_owner);
1836         xt_free_table_info(private);
1837 }
1838
1839 /* The built-in targets: standard (NULL) and error. */
1840 static struct xt_target arpt_standard_target __read_mostly = {
1841         .name           = ARPT_STANDARD_TARGET,
1842         .targetsize     = sizeof(int),
1843         .family         = NFPROTO_ARP,
1844 #ifdef CONFIG_COMPAT
1845         .compatsize     = sizeof(compat_int_t),
1846         .compat_from_user = compat_standard_from_user,
1847         .compat_to_user = compat_standard_to_user,
1848 #endif
1849 };
1850
1851 static struct xt_target arpt_error_target __read_mostly = {
1852         .name           = ARPT_ERROR_TARGET,
1853         .target         = arpt_error,
1854         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1855         .family         = NFPROTO_ARP,
1856 };
1857
1858 static struct nf_sockopt_ops arpt_sockopts = {
1859         .pf             = PF_INET,
1860         .set_optmin     = ARPT_BASE_CTL,
1861         .set_optmax     = ARPT_SO_SET_MAX+1,
1862         .set            = do_arpt_set_ctl,
1863 #ifdef CONFIG_COMPAT
1864         .compat_set     = compat_do_arpt_set_ctl,
1865 #endif
1866         .get_optmin     = ARPT_BASE_CTL,
1867         .get_optmax     = ARPT_SO_GET_MAX+1,
1868         .get            = do_arpt_get_ctl,
1869 #ifdef CONFIG_COMPAT
1870         .compat_get     = compat_do_arpt_get_ctl,
1871 #endif
1872         .owner          = THIS_MODULE,
1873 };
1874
1875 static int __net_init arp_tables_net_init(struct net *net)
1876 {
1877         return xt_proto_init(net, NFPROTO_ARP);
1878 }
1879
1880 static void __net_exit arp_tables_net_exit(struct net *net)
1881 {
1882         xt_proto_fini(net, NFPROTO_ARP);
1883 }
1884
1885 static struct pernet_operations arp_tables_net_ops = {
1886         .init = arp_tables_net_init,
1887         .exit = arp_tables_net_exit,
1888 };
1889
1890 static int __init arp_tables_init(void)
1891 {
1892         int ret;
1893
1894         ret = register_pernet_subsys(&arp_tables_net_ops);
1895         if (ret < 0)
1896                 goto err1;
1897
1898         /* Noone else will be downing sem now, so we won't sleep */
1899         ret = xt_register_target(&arpt_standard_target);
1900         if (ret < 0)
1901                 goto err2;
1902         ret = xt_register_target(&arpt_error_target);
1903         if (ret < 0)
1904                 goto err3;
1905
1906         /* Register setsockopt */
1907         ret = nf_register_sockopt(&arpt_sockopts);
1908         if (ret < 0)
1909                 goto err4;
1910
1911         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1912         return 0;
1913
1914 err4:
1915         xt_unregister_target(&arpt_error_target);
1916 err3:
1917         xt_unregister_target(&arpt_standard_target);
1918 err2:
1919         unregister_pernet_subsys(&arp_tables_net_ops);
1920 err1:
1921         return ret;
1922 }
1923
1924 static void __exit arp_tables_fini(void)
1925 {
1926         nf_unregister_sockopt(&arpt_sockopts);
1927         xt_unregister_target(&arpt_error_target);
1928         xt_unregister_target(&arpt_standard_target);
1929         unregister_pernet_subsys(&arp_tables_net_ops);
1930 }
1931
1932 EXPORT_SYMBOL(arpt_register_table);
1933 EXPORT_SYMBOL(arpt_unregister_table);
1934 EXPORT_SYMBOL(arpt_do_table);
1935
1936 module_init(arp_tables_init);
1937 module_exit(arp_tables_fini);