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 #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 = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 527                                         t->u.user.revision);
 528         if (IS_ERR(target)) {
 529                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 530                 ret = PTR_ERR(target);
 531                 goto out;
 532         }
 533         t->u.kernel.target = target;
 534
 535         ret = check_target(e, name);
 536         if (ret)
 537                 goto err;
 538         return 0;
 539 err:
 540         module_put(t->u.kernel.target->me);
 541 out:
 542         return ret;
 543 }
 544
 545 static bool check_underflow(const struct arpt_entry *e)
 546 {
 547         const struct arpt_entry_target *t;
 548         unsigned int verdict;
 549
 550         if (!unconditional(&e->arp))
 551                 return false;
 552         t = arpt_get_target_c(e);
 553         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 554                 return false;
 555         verdict = ((struct arpt_standard_target *)t)->verdict;
 556         verdict = -verdict - 1;
 557         return verdict == NF_DROP || verdict == NF_ACCEPT;
 558 }
 559
 560 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 561                                              struct xt_table_info *newinfo,
 562                                              const unsigned char *base,
 563                                              const unsigned char *limit,
 564                                              const unsigned int *hook_entries,
 565                                              const unsigned int *underflows,
 566                                              unsigned int valid_hooks)
 567 {
 568         unsigned int h;
 569
 570         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 571             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 572                 duprintf("Bad offset %p\n", e);
 573                 return -EINVAL;
 574         }
 575
 576         if (e->next_offset
 577             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 578                 duprintf("checking: element %p size %u\n",
 579                          e, e->next_offset);
 580                 return -EINVAL;
 581         }
 582
 583         /* Check hooks & underflows */
 584         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 585                 if (!(valid_hooks & (1 << h)))
 586                         continue;
 587                 if ((unsigned char *)e - base == hook_entries[h])
 588                         newinfo->hook_entry[h] = hook_entries[h];
 589                 if ((unsigned char *)e - base == underflows[h]) {
 590                         if (!check_underflow(e)) {
 591                                 pr_err("Underflows must be unconditional and "
 592                                        "use the STANDARD target with "
 593                                        "ACCEPT/DROP\n");
 594                                 return -EINVAL;
 595                         }
 596                         newinfo->underflow[h] = underflows[h];
 597                 }
 598         }
 599
 600         /* Clear counters and comefrom */
 601         e->counters = ((struct xt_counters) { 0, 0 });
 602         e->comefrom = 0;
 603         return 0;
 604 }
 605
 606 static inline void cleanup_entry(struct arpt_entry *e)
 607 {
 608         struct xt_tgdtor_param par;
 609         struct arpt_entry_target *t;
 610
 611         t = arpt_get_target(e);
 612         par.target   = t->u.kernel.target;
 613         par.targinfo = t->data;
 614         par.family   = NFPROTO_ARP;
 615         if (par.target->destroy != NULL)
 616                 par.target->destroy(&par);
 617         module_put(par.target->me);
 618 }
 619
 620 /* Checks and translates the user-supplied table segment (held in
 621  * newinfo).
 622  */
 623 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 624                            const struct arpt_replace *repl)
 625 {
 626         struct arpt_entry *iter;
 627         unsigned int i;
 628         int ret = 0;
 629
 630         newinfo->size = repl->size;
 631         newinfo->number = repl->num_entries;
 632
 633         /* Init all hooks to impossible value. */
 634         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 635                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 636                 newinfo->underflow[i] = 0xFFFFFFFF;
 637         }
 638
 639         duprintf("translate_table: size %u\n", newinfo->size);
 640         i = 0;
 641
 642         /* Walk through entries, checking offsets. */
 643         xt_entry_foreach(iter, entry0, newinfo->size) {
 644                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 645                                                  entry0 + repl->size,
 646                                                  repl->hook_entry,
 647                                                  repl->underflow,
 648                                                  repl->valid_hooks);
 649                 if (ret != 0)
 650                         break;
 651                 ++i;
 652                 if (strcmp(arpt_get_target(iter)->u.user.name,
 653                     XT_ERROR_TARGET) == 0)
 654                         ++newinfo->stacksize;
 655         }
 656         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 657         if (ret != 0)
 658                 return ret;
 659
 660         if (i != repl->num_entries) {
 661                 duprintf("translate_table: %u not %u entries\n",
 662                          i, repl->num_entries);
 663                 return -EINVAL;
 664         }
 665
 666         /* Check hooks all assigned */
 667         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 668                 /* Only hooks which are valid */
 669                 if (!(repl->valid_hooks & (1 << i)))
 670                         continue;
 671                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 672                         duprintf("Invalid hook entry %u %u\n",
 673                                  i, repl->hook_entry[i]);
 674                         return -EINVAL;
 675                 }
 676                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 677                         duprintf("Invalid underflow %u %u\n",
 678                                  i, repl->underflow[i]);
 679                         return -EINVAL;
 680                 }
 681         }
 682
 683         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 684                 duprintf("Looping hook\n");
 685                 return -ELOOP;
 686         }
 687
 688         /* Finally, each sanity check must pass */
 689         i = 0;
 690         xt_entry_foreach(iter, entry0, newinfo->size) {
 691                 ret = find_check_entry(iter, repl->name, repl->size);
 692                 if (ret != 0)
 693                         break;
 694                 ++i;
 695         }
 696
 697         if (ret != 0) {
 698                 xt_entry_foreach(iter, entry0, newinfo->size) {
 699                         if (i-- == 0)
 700                                 break;
 701                         cleanup_entry(iter);
 702                 }
 703                 return ret;
 704         }
 705
 706         /* And one copy for every other CPU */
 707         for_each_possible_cpu(i) {
 708                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 709                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 710         }
 711
 712         return ret;
 713 }
 714
 715 static void get_counters(const struct xt_table_info *t,
 716                          struct xt_counters counters[])
 717 {
 718         struct arpt_entry *iter;
 719         unsigned int cpu;
 720         unsigned int i;
 721         unsigned int curcpu;
 722
 723         /* Instead of clearing (by a previous call to memset())
 724          * the counters and using adds, we set the counters
 725          * with data used by 'current' CPU
 726          *
 727          * Bottom half has to be disabled to prevent deadlock
 728          * if new softirq were to run and call ipt_do_table
 729          */
 730         local_bh_disable();
 731         curcpu = smp_processor_id();
 732
 733         i = 0;
 734         xt_entry_foreach(iter, t->entries[curcpu], t->size) {
 735                 SET_COUNTER(counters[i], iter->counters.bcnt,
 736                             iter->counters.pcnt);
 737                 ++i;
 738         }
 739
 740         for_each_possible_cpu(cpu) {
 741                 if (cpu == curcpu)
 742                         continue;
 743                 i = 0;
 744                 xt_info_wrlock(cpu);
 745                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 746                         ADD_COUNTER(counters[i], iter->counters.bcnt,
 747                                     iter->counters.pcnt);
 748                         ++i;
 749                 }
 750                 xt_info_wrunlock(cpu);
 751         }
 752         local_bh_enable();
 753 }
 754
 755 static struct xt_counters *alloc_counters(const struct xt_table *table)
 756 {
 757         unsigned int countersize;
 758         struct xt_counters *counters;
 759         const struct xt_table_info *private = table->private;
 760
 761         /* We need atomic snapshot of counters: rest doesn't change
 762          * (other than comefrom, which userspace doesn't care
 763          * about).
 764          */
 765         countersize = sizeof(struct xt_counters) * private->number;
 766         counters = vmalloc_node(countersize, numa_node_id());
 767
 768         if (counters == NULL)
 769                 return ERR_PTR(-ENOMEM);
 770
 771         get_counters(private, counters);
 772
 773         return counters;
 774 }
 775
 776 static int copy_entries_to_user(unsigned int total_size,
 777                                 const struct xt_table *table,
 778                                 void __user *userptr)
 779 {
 780         unsigned int off, num;
 781         const struct arpt_entry *e;
 782         struct xt_counters *counters;
 783         struct xt_table_info *private = table->private;
 784         int ret = 0;
 785         void *loc_cpu_entry;
 786
 787         counters = alloc_counters(table);
 788         if (IS_ERR(counters))
 789                 return PTR_ERR(counters);
 790
 791         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 792         /* ... then copy entire thing ... */
 793         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 794                 ret = -EFAULT;
 795                 goto free_counters;
 796         }
 797
 798         /* FIXME: use iterator macros --RR */
 799         /* ... then go back and fix counters and names */
 800         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 801                 const struct arpt_entry_target *t;
 802
 803                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 804                 if (copy_to_user(userptr + off
 805                                  + offsetof(struct arpt_entry, counters),
 806                                  &counters[num],
 807                                  sizeof(counters[num])) != 0) {
 808                         ret = -EFAULT;
 809                         goto free_counters;
 810                 }
 811
 812                 t = arpt_get_target_c(e);
 813                 if (copy_to_user(userptr + off + e->target_offset
 814                                  + offsetof(struct arpt_entry_target,
 815                                             u.user.name),
 816                                  t->u.kernel.target->name,
 817                                  strlen(t->u.kernel.target->name)+1) != 0) {
 818                         ret = -EFAULT;
 819                         goto free_counters;
 820                 }
 821         }
 822
 823  free_counters:
 824         vfree(counters);
 825         return ret;
 826 }
 827
 828 #ifdef CONFIG_COMPAT
 829 static void compat_standard_from_user(void *dst, const void *src)
 830 {
 831         int v = *(compat_int_t *)src;
 832
 833         if (v > 0)
 834                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 835         memcpy(dst, &v, sizeof(v));
 836 }
 837
 838 static int compat_standard_to_user(void __user *dst, const void *src)
 839 {
 840         compat_int_t cv = *(int *)src;
 841
 842         if (cv > 0)
 843                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 844         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 845 }
 846
 847 static int compat_calc_entry(const struct arpt_entry *e,
 848                              const struct xt_table_info *info,
 849                              const void *base, struct xt_table_info *newinfo)
 850 {
 851         const struct arpt_entry_target *t;
 852         unsigned int entry_offset;
 853         int off, i, ret;
 854
 855         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 856         entry_offset = (void *)e - base;
 857
 858         t = arpt_get_target_c(e);
 859         off += xt_compat_target_offset(t->u.kernel.target);
 860         newinfo->size -= off;
 861         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 862         if (ret)
 863                 return ret;
 864
 865         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 866                 if (info->hook_entry[i] &&
 867                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 868                         newinfo->hook_entry[i] -= off;
 869                 if (info->underflow[i] &&
 870                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 871                         newinfo->underflow[i] -= off;
 872         }
 873         return 0;
 874 }
 875
 876 static int compat_table_info(const struct xt_table_info *info,
 877                              struct xt_table_info *newinfo)
 878 {
 879         struct arpt_entry *iter;
 880         void *loc_cpu_entry;
 881         int ret;
 882
 883         if (!newinfo || !info)
 884                 return -EINVAL;
 885
 886         /* we dont care about newinfo->entries[] */
 887         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 888         newinfo->initial_entries = 0;
 889         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 890         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 891                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 892                 if (ret != 0)
 893                         return ret;
 894         }
 895         return 0;
 896 }
 897 #endif
 898
 899 static int get_info(struct net *net, void __user *user,
 900                     const int *len, int compat)
 901 {
 902         char name[ARPT_TABLE_MAXNAMELEN];
 903         struct xt_table *t;
 904         int ret;
 905
 906         if (*len != sizeof(struct arpt_getinfo)) {
 907                 duprintf("length %u != %Zu\n", *len,
 908                          sizeof(struct arpt_getinfo));
 909                 return -EINVAL;
 910         }
 911
 912         if (copy_from_user(name, user, sizeof(name)) != 0)
 913                 return -EFAULT;
 914
 915         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 916 #ifdef CONFIG_COMPAT
 917         if (compat)
 918                 xt_compat_lock(NFPROTO_ARP);
 919 #endif
 920         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 921                                     "arptable_%s", name);
 922         if (t && !IS_ERR(t)) {
 923                 struct arpt_getinfo info;
 924                 const struct xt_table_info *private = t->private;
 925 #ifdef CONFIG_COMPAT
 926                 struct xt_table_info tmp;
 927
 928                 if (compat) {
 929                         ret = compat_table_info(private, &tmp);
 930                         xt_compat_flush_offsets(NFPROTO_ARP);
 931                         private = &tmp;
 932                 }
 933 #endif
 934                 info.valid_hooks = t->valid_hooks;
 935                 memcpy(info.hook_entry, private->hook_entry,
 936                        sizeof(info.hook_entry));
 937                 memcpy(info.underflow, private->underflow,
 938                        sizeof(info.underflow));
 939                 info.num_entries = private->number;
 940                 info.size = private->size;
 941                 strcpy(info.name, name);
 942
 943                 if (copy_to_user(user, &info, *len) != 0)
 944                         ret = -EFAULT;
 945                 else
 946                         ret = 0;
 947                 xt_table_unlock(t);
 948                 module_put(t->me);
 949         } else
 950                 ret = t ? PTR_ERR(t) : -ENOENT;
 951 #ifdef CONFIG_COMPAT
 952         if (compat)
 953                 xt_compat_unlock(NFPROTO_ARP);
 954 #endif
 955         return ret;
 956 }
 957
 958 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 959                        const int *len)
 960 {
 961         int ret;
 962         struct arpt_get_entries get;
 963         struct xt_table *t;
 964
 965         if (*len < sizeof(get)) {
 966                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 967                 return -EINVAL;
 968         }
 969         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 970                 return -EFAULT;
 971         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 972                 duprintf("get_entries: %u != %Zu\n", *len,
 973                          sizeof(struct arpt_get_entries) + get.size);
 974                 return -EINVAL;
 975         }
 976
 977         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 978         if (t && !IS_ERR(t)) {
 979                 const struct xt_table_info *private = t->private;
 980
 981                 duprintf("t->private->number = %u\n",
 982                          private->number);
 983                 if (get.size == private->size)
 984                         ret = copy_entries_to_user(private->size,
 985                                                    t, uptr->entrytable);
 986                 else {
 987                         duprintf("get_entries: I've got %u not %u!\n",
 988                                  private->size, get.size);
 989                         ret = -EAGAIN;
 990                 }
 991                 module_put(t->me);
 992                 xt_table_unlock(t);
 993         } else
 994                 ret = t ? PTR_ERR(t) : -ENOENT;
 995
 996         return ret;
 997 }
 998
 999 static int __do_replace(struct net *net, const char *name,
1000                         unsigned int valid_hooks,
1001                         struct xt_table_info *newinfo,
1002                         unsigned int num_counters,
1003                         void __user *counters_ptr)
1004 {
1005         int ret;
1006         struct xt_table *t;
1007         struct xt_table_info *oldinfo;
1008         struct xt_counters *counters;
1009         void *loc_cpu_old_entry;
1010         struct arpt_entry *iter;
1011
1012         ret = 0;
1013         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
1014                                 numa_node_id());
1015         if (!counters) {
1016                 ret = -ENOMEM;
1017                 goto out;
1018         }
1019
1020         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1021                                     "arptable_%s", name);
1022         if (!t || IS_ERR(t)) {
1023                 ret = t ? PTR_ERR(t) : -ENOENT;
1024                 goto free_newinfo_counters_untrans;
1025         }
1026
1027         /* You lied! */
1028         if (valid_hooks != t->valid_hooks) {
1029                 duprintf("Valid hook crap: %08X vs %08X\n",
1030                          valid_hooks, t->valid_hooks);
1031                 ret = -EINVAL;
1032                 goto put_module;
1033         }
1034
1035         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1036         if (!oldinfo)
1037                 goto put_module;
1038
1039         /* Update module usage count based on number of rules */
1040         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1041                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1042         if ((oldinfo->number > oldinfo->initial_entries) ||
1043             (newinfo->number <= oldinfo->initial_entries))
1044                 module_put(t->me);
1045         if ((oldinfo->number > oldinfo->initial_entries) &&
1046             (newinfo->number <= oldinfo->initial_entries))
1047                 module_put(t->me);
1048
1049         /* Get the old counters, and synchronize with replace */
1050         get_counters(oldinfo, counters);
1051
1052         /* Decrease module usage counts and free resource */
1053         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1054         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1055                 cleanup_entry(iter);
1056
1057         xt_free_table_info(oldinfo);
1058         if (copy_to_user(counters_ptr, counters,
1059                          sizeof(struct xt_counters) * num_counters) != 0)
1060                 ret = -EFAULT;
1061         vfree(counters);
1062         xt_table_unlock(t);
1063         return ret;
1064
1065  put_module:
1066         module_put(t->me);
1067         xt_table_unlock(t);
1068  free_newinfo_counters_untrans:
1069         vfree(counters);
1070  out:
1071         return ret;
1072 }
1073
1074 static int do_replace(struct net *net, const void __user *user,
1075                       unsigned int len)
1076 {
1077         int ret;
1078         struct arpt_replace tmp;
1079         struct xt_table_info *newinfo;
1080         void *loc_cpu_entry;
1081         struct arpt_entry *iter;
1082
1083         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1084                 return -EFAULT;
1085
1086         /* overflow check */
1087         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1088                 return -ENOMEM;
1089
1090         newinfo = xt_alloc_table_info(tmp.size);
1091         if (!newinfo)
1092                 return -ENOMEM;
1093
1094         /* choose the copy that is on our node/cpu */
1095         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1096         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1097                            tmp.size) != 0) {
1098                 ret = -EFAULT;
1099                 goto free_newinfo;
1100         }
1101
1102         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1103         if (ret != 0)
1104                 goto free_newinfo;
1105
1106         duprintf("arp_tables: Translated table\n");
1107
1108         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1109                            tmp.num_counters, tmp.counters);
1110         if (ret)
1111                 goto free_newinfo_untrans;
1112         return 0;
1113
1114  free_newinfo_untrans:
1115         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1116                 cleanup_entry(iter);
1117  free_newinfo:
1118         xt_free_table_info(newinfo);
1119         return ret;
1120 }
1121
1122 static int do_add_counters(struct net *net, const void __user *user,
1123                            unsigned int len, int compat)
1124 {
1125         unsigned int i, curcpu;
1126         struct xt_counters_info tmp;
1127         struct xt_counters *paddc;
1128         unsigned int num_counters;
1129         const char *name;
1130         int size;
1131         void *ptmp;
1132         struct xt_table *t;
1133         const struct xt_table_info *private;
1134         int ret = 0;
1135         void *loc_cpu_entry;
1136         struct arpt_entry *iter;
1137 #ifdef CONFIG_COMPAT
1138         struct compat_xt_counters_info compat_tmp;
1139
1140         if (compat) {
1141                 ptmp = &compat_tmp;
1142                 size = sizeof(struct compat_xt_counters_info);
1143         } else
1144 #endif
1145         {
1146                 ptmp = &tmp;
1147                 size = sizeof(struct xt_counters_info);
1148         }
1149
1150         if (copy_from_user(ptmp, user, size) != 0)
1151                 return -EFAULT;
1152
1153 #ifdef CONFIG_COMPAT
1154         if (compat) {
1155                 num_counters = compat_tmp.num_counters;
1156                 name = compat_tmp.name;
1157         } else
1158 #endif
1159         {
1160                 num_counters = tmp.num_counters;
1161                 name = tmp.name;
1162         }
1163
1164         if (len != size + num_counters * sizeof(struct xt_counters))
1165                 return -EINVAL;
1166
1167         paddc = vmalloc_node(len - size, numa_node_id());
1168         if (!paddc)
1169                 return -ENOMEM;
1170
1171         if (copy_from_user(paddc, user + size, len - size) != 0) {
1172                 ret = -EFAULT;
1173                 goto free;
1174         }
1175
1176         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1177         if (!t || IS_ERR(t)) {
1178                 ret = t ? PTR_ERR(t) : -ENOENT;
1179                 goto free;
1180         }
1181
1182         local_bh_disable();
1183         private = t->private;
1184         if (private->number != num_counters) {
1185                 ret = -EINVAL;
1186                 goto unlock_up_free;
1187         }
1188
1189         i = 0;
1190         /* Choose the copy that is on our node */
1191         curcpu = smp_processor_id();
1192         loc_cpu_entry = private->entries[curcpu];
1193         xt_info_wrlock(curcpu);
1194         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1195                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1196                 ++i;
1197         }
1198         xt_info_wrunlock(curcpu);
1199  unlock_up_free:
1200         local_bh_enable();
1201         xt_table_unlock(t);
1202         module_put(t->me);
1203  free:
1204         vfree(paddc);
1205
1206         return ret;
1207 }
1208
1209 #ifdef CONFIG_COMPAT
1210 static inline void compat_release_entry(struct compat_arpt_entry *e)
1211 {
1212         struct arpt_entry_target *t;
1213
1214         t = compat_arpt_get_target(e);
1215         module_put(t->u.kernel.target->me);
1216 }
1217
1218 static inline int
1219 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1220                                   struct xt_table_info *newinfo,
1221                                   unsigned int *size,
1222                                   const unsigned char *base,
1223                                   const unsigned char *limit,
1224                                   const unsigned int *hook_entries,
1225                                   const unsigned int *underflows,
1226                                   const char *name)
1227 {
1228         struct arpt_entry_target *t;
1229         struct xt_target *target;
1230         unsigned int entry_offset;
1231         int ret, off, h;
1232
1233         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1234         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1235             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1236                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1237                 return -EINVAL;
1238         }
1239
1240         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1241                              sizeof(struct compat_xt_entry_target)) {
1242                 duprintf("checking: element %p size %u\n",
1243                          e, e->next_offset);
1244                 return -EINVAL;
1245         }
1246
1247         /* For purposes of check_entry casting the compat entry is fine */
1248         ret = check_entry((struct arpt_entry *)e, name);
1249         if (ret)
1250                 return ret;
1251
1252         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1253         entry_offset = (void *)e - (void *)base;
1254
1255         t = compat_arpt_get_target(e);
1256         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1257                                         t->u.user.revision);
1258         if (IS_ERR(target)) {
1259                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1260                          t->u.user.name);
1261                 ret = PTR_ERR(target);
1262                 goto out;
1263         }
1264         t->u.kernel.target = target;
1265
1266         off += xt_compat_target_offset(target);
1267         *size += off;
1268         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1269         if (ret)
1270                 goto release_target;
1271
1272         /* Check hooks & underflows */
1273         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1274                 if ((unsigned char *)e - base == hook_entries[h])
1275                         newinfo->hook_entry[h] = hook_entries[h];
1276                 if ((unsigned char *)e - base == underflows[h])
1277                         newinfo->underflow[h] = underflows[h];
1278         }
1279
1280         /* Clear counters and comefrom */
1281         memset(&e->counters, 0, sizeof(e->counters));
1282         e->comefrom = 0;
1283         return 0;
1284
1285 release_target:
1286         module_put(t->u.kernel.target->me);
1287 out:
1288         return ret;
1289 }
1290
1291 static int
1292 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1293                             unsigned int *size, const char *name,
1294                             struct xt_table_info *newinfo, unsigned char *base)
1295 {
1296         struct arpt_entry_target *t;
1297         struct xt_target *target;
1298         struct arpt_entry *de;
1299         unsigned int origsize;
1300         int ret, h;
1301
1302         ret = 0;
1303         origsize = *size;
1304         de = (struct arpt_entry *)*dstptr;
1305         memcpy(de, e, sizeof(struct arpt_entry));
1306         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1307
1308         *dstptr += sizeof(struct arpt_entry);
1309         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1310
1311         de->target_offset = e->target_offset - (origsize - *size);
1312         t = compat_arpt_get_target(e);
1313         target = t->u.kernel.target;
1314         xt_compat_target_from_user(t, dstptr, size);
1315
1316         de->next_offset = e->next_offset - (origsize - *size);
1317         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1318                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1319                         newinfo->hook_entry[h] -= origsize - *size;
1320                 if ((unsigned char *)de - base < newinfo->underflow[h])
1321                         newinfo->underflow[h] -= origsize - *size;
1322         }
1323         return ret;
1324 }
1325
1326 static int translate_compat_table(const char *name,
1327                                   unsigned int valid_hooks,
1328                                   struct xt_table_info **pinfo,
1329                                   void **pentry0,
1330                                   unsigned int total_size,
1331                                   unsigned int number,
1332                                   unsigned int *hook_entries,
1333                                   unsigned int *underflows)
1334 {
1335         unsigned int i, j;
1336         struct xt_table_info *newinfo, *info;
1337         void *pos, *entry0, *entry1;
1338         struct compat_arpt_entry *iter0;
1339         struct arpt_entry *iter1;
1340         unsigned int size;
1341         int ret = 0;
1342
1343         info = *pinfo;
1344         entry0 = *pentry0;
1345         size = total_size;
1346         info->number = number;
1347
1348         /* Init all hooks to impossible value. */
1349         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1350                 info->hook_entry[i] = 0xFFFFFFFF;
1351                 info->underflow[i] = 0xFFFFFFFF;
1352         }
1353
1354         duprintf("translate_compat_table: size %u\n", info->size);
1355         j = 0;
1356         xt_compat_lock(NFPROTO_ARP);
1357         /* Walk through entries, checking offsets. */
1358         xt_entry_foreach(iter0, entry0, total_size) {
1359                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1360                                                         entry0,
1361                                                         entry0 + total_size,
1362                                                         hook_entries,
1363                                                         underflows,
1364                                                         name);
1365                 if (ret != 0)
1366                         goto out_unlock;
1367                 ++j;
1368         }
1369
1370         ret = -EINVAL;
1371         if (j != number) {
1372                 duprintf("translate_compat_table: %u not %u entries\n",
1373                          j, number);
1374                 goto out_unlock;
1375         }
1376
1377         /* Check hooks all assigned */
1378         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1379                 /* Only hooks which are valid */
1380                 if (!(valid_hooks & (1 << i)))
1381                         continue;
1382                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1383                         duprintf("Invalid hook entry %u %u\n",
1384                                  i, hook_entries[i]);
1385                         goto out_unlock;
1386                 }
1387                 if (info->underflow[i] == 0xFFFFFFFF) {
1388                         duprintf("Invalid underflow %u %u\n",
1389                                  i, underflows[i]);
1390                         goto out_unlock;
1391                 }
1392         }
1393
1394         ret = -ENOMEM;
1395         newinfo = xt_alloc_table_info(size);
1396         if (!newinfo)
1397                 goto out_unlock;
1398
1399         newinfo->number = number;
1400         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1401                 newinfo->hook_entry[i] = info->hook_entry[i];
1402                 newinfo->underflow[i] = info->underflow[i];
1403         }
1404         entry1 = newinfo->entries[raw_smp_processor_id()];
1405         pos = entry1;
1406         size = total_size;
1407         xt_entry_foreach(iter0, entry0, total_size) {
1408                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1409                                                   name, newinfo, entry1);
1410                 if (ret != 0)
1411                         break;
1412         }
1413         xt_compat_flush_offsets(NFPROTO_ARP);
1414         xt_compat_unlock(NFPROTO_ARP);
1415         if (ret)
1416                 goto free_newinfo;
1417
1418         ret = -ELOOP;
1419         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1420                 goto free_newinfo;
1421
1422         i = 0;
1423         xt_entry_foreach(iter1, entry1, newinfo->size) {
1424                 ret = check_target(iter1, name);
1425                 if (ret != 0)
1426                         break;
1427                 ++i;
1428         }
1429         if (ret) {
1430                 /*
1431                  * The first i matches need cleanup_entry (calls ->destroy)
1432                  * because they had called ->check already. The other j-i
1433                  * entries need only release.
1434                  */
1435                 int skip = i;
1436                 j -= i;
1437                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1438                         if (skip-- > 0)
1439                                 continue;
1440                         if (j-- == 0)
1441                                 break;
1442                         compat_release_entry(iter0);
1443                 }
1444                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1445                         if (i-- == 0)
1446                                 break;
1447                         cleanup_entry(iter1);
1448                 }
1449                 xt_free_table_info(newinfo);
1450                 return ret;
1451         }
1452
1453         /* And one copy for every other CPU */
1454         for_each_possible_cpu(i)
1455                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1456                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1457
1458         *pinfo = newinfo;
1459         *pentry0 = entry1;
1460         xt_free_table_info(info);
1461         return 0;
1462
1463 free_newinfo:
1464         xt_free_table_info(newinfo);
1465 out:
1466         xt_entry_foreach(iter0, entry0, total_size) {
1467                 if (j-- == 0)
1468                         break;
1469                 compat_release_entry(iter0);
1470         }
1471         return ret;
1472 out_unlock:
1473         xt_compat_flush_offsets(NFPROTO_ARP);
1474         xt_compat_unlock(NFPROTO_ARP);
1475         goto out;
1476 }
1477
1478 struct compat_arpt_replace {
1479         char                            name[ARPT_TABLE_MAXNAMELEN];
1480         u32                             valid_hooks;
1481         u32                             num_entries;
1482         u32                             size;
1483         u32                             hook_entry[NF_ARP_NUMHOOKS];
1484         u32                             underflow[NF_ARP_NUMHOOKS];
1485         u32                             num_counters;
1486         compat_uptr_t                   counters;
1487         struct compat_arpt_entry        entries[0];
1488 };
1489
1490 static int compat_do_replace(struct net *net, void __user *user,
1491                              unsigned int len)
1492 {
1493         int ret;
1494         struct compat_arpt_replace tmp;
1495         struct xt_table_info *newinfo;
1496         void *loc_cpu_entry;
1497         struct arpt_entry *iter;
1498
1499         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1500                 return -EFAULT;
1501
1502         /* overflow check */
1503         if (tmp.size >= INT_MAX / num_possible_cpus())
1504                 return -ENOMEM;
1505         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1506                 return -ENOMEM;
1507
1508         newinfo = xt_alloc_table_info(tmp.size);
1509         if (!newinfo)
1510                 return -ENOMEM;
1511
1512         /* choose the copy that is on our node/cpu */
1513         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1514         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1515                 ret = -EFAULT;
1516                 goto free_newinfo;
1517         }
1518
1519         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1520                                      &newinfo, &loc_cpu_entry, tmp.size,
1521                                      tmp.num_entries, tmp.hook_entry,
1522                                      tmp.underflow);
1523         if (ret != 0)
1524                 goto free_newinfo;
1525
1526         duprintf("compat_do_replace: Translated table\n");
1527
1528         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1529                            tmp.num_counters, compat_ptr(tmp.counters));
1530         if (ret)
1531                 goto free_newinfo_untrans;
1532         return 0;
1533
1534  free_newinfo_untrans:
1535         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1536                 cleanup_entry(iter);
1537  free_newinfo:
1538         xt_free_table_info(newinfo);
1539         return ret;
1540 }
1541
1542 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1543                                   unsigned int len)
1544 {
1545         int ret;
1546
1547         if (!capable(CAP_NET_ADMIN))
1548                 return -EPERM;
1549
1550         switch (cmd) {
1551         case ARPT_SO_SET_REPLACE:
1552                 ret = compat_do_replace(sock_net(sk), user, len);
1553                 break;
1554
1555         case ARPT_SO_SET_ADD_COUNTERS:
1556                 ret = do_add_counters(sock_net(sk), user, len, 1);
1557                 break;
1558
1559         default:
1560                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1561                 ret = -EINVAL;
1562         }
1563
1564         return ret;
1565 }
1566
1567 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1568                                      compat_uint_t *size,
1569                                      struct xt_counters *counters,
1570                                      unsigned int i)
1571 {
1572         struct arpt_entry_target *t;
1573         struct compat_arpt_entry __user *ce;
1574         u_int16_t target_offset, next_offset;
1575         compat_uint_t origsize;
1576         int ret;
1577
1578         origsize = *size;
1579         ce = (struct compat_arpt_entry __user *)*dstptr;
1580         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1581             copy_to_user(&ce->counters, &counters[i],
1582             sizeof(counters[i])) != 0)
1583                 return -EFAULT;
1584
1585         *dstptr += sizeof(struct compat_arpt_entry);
1586         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1587
1588         target_offset = e->target_offset - (origsize - *size);
1589
1590         t = arpt_get_target(e);
1591         ret = xt_compat_target_to_user(t, dstptr, size);
1592         if (ret)
1593                 return ret;
1594         next_offset = e->next_offset - (origsize - *size);
1595         if (put_user(target_offset, &ce->target_offset) != 0 ||
1596             put_user(next_offset, &ce->next_offset) != 0)
1597                 return -EFAULT;
1598         return 0;
1599 }
1600
1601 static int compat_copy_entries_to_user(unsigned int total_size,
1602                                        struct xt_table *table,
1603                                        void __user *userptr)
1604 {
1605         struct xt_counters *counters;
1606         const struct xt_table_info *private = table->private;
1607         void __user *pos;
1608         unsigned int size;
1609         int ret = 0;
1610         void *loc_cpu_entry;
1611         unsigned int i = 0;
1612         struct arpt_entry *iter;
1613
1614         counters = alloc_counters(table);
1615         if (IS_ERR(counters))
1616                 return PTR_ERR(counters);
1617
1618         /* choose the copy on our node/cpu */
1619         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1620         pos = userptr;
1621         size = total_size;
1622         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1623                 ret = compat_copy_entry_to_user(iter, &pos,
1624                                                 &size, counters, i++);
1625                 if (ret != 0)
1626                         break;
1627         }
1628         vfree(counters);
1629         return ret;
1630 }
1631
1632 struct compat_arpt_get_entries {
1633         char name[ARPT_TABLE_MAXNAMELEN];
1634         compat_uint_t size;
1635         struct compat_arpt_entry entrytable[0];
1636 };
1637
1638 static int compat_get_entries(struct net *net,
1639                               struct compat_arpt_get_entries __user *uptr,
1640                               int *len)
1641 {
1642         int ret;
1643         struct compat_arpt_get_entries get;
1644         struct xt_table *t;
1645
1646         if (*len < sizeof(get)) {
1647                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1648                 return -EINVAL;
1649         }
1650         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1651                 return -EFAULT;
1652         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1653                 duprintf("compat_get_entries: %u != %zu\n",
1654                          *len, sizeof(get) + get.size);
1655                 return -EINVAL;
1656         }
1657
1658         xt_compat_lock(NFPROTO_ARP);
1659         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1660         if (t && !IS_ERR(t)) {
1661                 const struct xt_table_info *private = t->private;
1662                 struct xt_table_info info;
1663
1664                 duprintf("t->private->number = %u\n", private->number);
1665                 ret = compat_table_info(private, &info);
1666                 if (!ret && get.size == info.size) {
1667                         ret = compat_copy_entries_to_user(private->size,
1668                                                           t, uptr->entrytable);
1669                 } else if (!ret) {
1670                         duprintf("compat_get_entries: I've got %u not %u!\n",
1671                                  private->size, get.size);
1672                         ret = -EAGAIN;
1673                 }
1674                 xt_compat_flush_offsets(NFPROTO_ARP);
1675                 module_put(t->me);
1676                 xt_table_unlock(t);
1677         } else
1678                 ret = t ? PTR_ERR(t) : -ENOENT;
1679
1680         xt_compat_unlock(NFPROTO_ARP);
1681         return ret;
1682 }
1683
1684 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1685
1686 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1687                                   int *len)
1688 {
1689         int ret;
1690
1691         if (!capable(CAP_NET_ADMIN))
1692                 return -EPERM;
1693
1694         switch (cmd) {
1695         case ARPT_SO_GET_INFO:
1696                 ret = get_info(sock_net(sk), user, len, 1);
1697                 break;
1698         case ARPT_SO_GET_ENTRIES:
1699                 ret = compat_get_entries(sock_net(sk), user, len);
1700                 break;
1701         default:
1702                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1703         }
1704         return ret;
1705 }
1706 #endif
1707
1708 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1709 {
1710         int ret;
1711
1712         if (!capable(CAP_NET_ADMIN))
1713                 return -EPERM;
1714
1715         switch (cmd) {
1716         case ARPT_SO_SET_REPLACE:
1717                 ret = do_replace(sock_net(sk), user, len);
1718                 break;
1719
1720         case ARPT_SO_SET_ADD_COUNTERS:
1721                 ret = do_add_counters(sock_net(sk), user, len, 0);
1722                 break;
1723
1724         default:
1725                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1726                 ret = -EINVAL;
1727         }
1728
1729         return ret;
1730 }
1731
1732 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1733 {
1734         int ret;
1735
1736         if (!capable(CAP_NET_ADMIN))
1737                 return -EPERM;
1738
1739         switch (cmd) {
1740         case ARPT_SO_GET_INFO:
1741                 ret = get_info(sock_net(sk), user, len, 0);
1742                 break;
1743
1744         case ARPT_SO_GET_ENTRIES:
1745                 ret = get_entries(sock_net(sk), user, len);
1746                 break;
1747
1748         case ARPT_SO_GET_REVISION_TARGET: {
1749                 struct xt_get_revision rev;
1750
1751                 if (*len != sizeof(rev)) {
1752                         ret = -EINVAL;
1753                         break;
1754                 }
1755                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1756                         ret = -EFAULT;
1757                         break;
1758                 }
1759
1760                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1761                                                          rev.revision, 1, &ret),
1762                                         "arpt_%s", rev.name);
1763                 break;
1764         }
1765
1766         default:
1767                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1768                 ret = -EINVAL;
1769         }
1770
1771         return ret;
1772 }
1773
1774 struct xt_table *arpt_register_table(struct net *net,
1775                                      const struct xt_table *table,
1776                                      const struct arpt_replace *repl)
1777 {
1778         int ret;
1779         struct xt_table_info *newinfo;
1780         struct xt_table_info bootstrap = {0};
1781         void *loc_cpu_entry;
1782         struct xt_table *new_table;
1783
1784         newinfo = xt_alloc_table_info(repl->size);
1785         if (!newinfo) {
1786                 ret = -ENOMEM;
1787                 goto out;
1788         }
1789
1790         /* choose the copy on our node/cpu */
1791         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1792         memcpy(loc_cpu_entry, repl->entries, repl->size);
1793
1794         ret = translate_table(newinfo, loc_cpu_entry, repl);
1795         duprintf("arpt_register_table: translate table gives %d\n", ret);
1796         if (ret != 0)
1797                 goto out_free;
1798
1799         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1800         if (IS_ERR(new_table)) {
1801                 ret = PTR_ERR(new_table);
1802                 goto out_free;
1803         }
1804         return new_table;
1805
1806 out_free:
1807         xt_free_table_info(newinfo);
1808 out:
1809         return ERR_PTR(ret);
1810 }
1811
1812 void arpt_unregister_table(struct xt_table *table)
1813 {
1814         struct xt_table_info *private;
1815         void *loc_cpu_entry;
1816         struct module *table_owner = table->me;
1817         struct arpt_entry *iter;
1818
1819         private = xt_unregister_table(table);
1820
1821         /* Decrease module usage counts and free resources */
1822         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1823         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1824                 cleanup_entry(iter);
1825         if (private->number > private->initial_entries)
1826                 module_put(table_owner);
1827         xt_free_table_info(private);
1828 }
1829
1830 /* The built-in targets: standard (NULL) and error. */
1831 static struct xt_target arpt_standard_target __read_mostly = {
1832         .name           = ARPT_STANDARD_TARGET,
1833         .targetsize     = sizeof(int),
1834         .family         = NFPROTO_ARP,
1835 #ifdef CONFIG_COMPAT
1836         .compatsize     = sizeof(compat_int_t),
1837         .compat_from_user = compat_standard_from_user,
1838         .compat_to_user = compat_standard_to_user,
1839 #endif
1840 };
1841
1842 static struct xt_target arpt_error_target __read_mostly = {
1843         .name           = ARPT_ERROR_TARGET,
1844         .target         = arpt_error,
1845         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1846         .family         = NFPROTO_ARP,
1847 };
1848
1849 static struct nf_sockopt_ops arpt_sockopts = {
1850         .pf             = PF_INET,
1851         .set_optmin     = ARPT_BASE_CTL,
1852         .set_optmax     = ARPT_SO_SET_MAX+1,
1853         .set            = do_arpt_set_ctl,
1854 #ifdef CONFIG_COMPAT
1855         .compat_set     = compat_do_arpt_set_ctl,
1856 #endif
1857         .get_optmin     = ARPT_BASE_CTL,
1858         .get_optmax     = ARPT_SO_GET_MAX+1,
1859         .get            = do_arpt_get_ctl,
1860 #ifdef CONFIG_COMPAT
1861         .compat_get     = compat_do_arpt_get_ctl,
1862 #endif
1863         .owner          = THIS_MODULE,
1864 };
1865
1866 static int __net_init arp_tables_net_init(struct net *net)
1867 {
1868         return xt_proto_init(net, NFPROTO_ARP);
1869 }
1870
1871 static void __net_exit arp_tables_net_exit(struct net *net)
1872 {
1873         xt_proto_fini(net, NFPROTO_ARP);
1874 }
1875
1876 static struct pernet_operations arp_tables_net_ops = {
1877         .init = arp_tables_net_init,
1878         .exit = arp_tables_net_exit,
1879 };
1880
1881 static int __init arp_tables_init(void)
1882 {
1883         int ret;
1884
1885         ret = register_pernet_subsys(&arp_tables_net_ops);
1886         if (ret < 0)
1887                 goto err1;
1888
1889         /* Noone else will be downing sem now, so we won't sleep */
1890         ret = xt_register_target(&arpt_standard_target);
1891         if (ret < 0)
1892                 goto err2;
1893         ret = xt_register_target(&arpt_error_target);
1894         if (ret < 0)
1895                 goto err3;
1896
1897         /* Register setsockopt */
1898         ret = nf_register_sockopt(&arpt_sockopts);
1899         if (ret < 0)
1900                 goto err4;
1901
1902         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1903         return 0;
1904
1905 err4:
1906         xt_unregister_target(&arpt_error_target);
1907 err3:
1908         xt_unregister_target(&arpt_standard_target);
1909 err2:
1910         unregister_pernet_subsys(&arp_tables_net_ops);
1911 err1:
1912         return ret;
1913 }
1914
1915 static void __exit arp_tables_fini(void)
1916 {
1917         nf_unregister_sockopt(&arpt_sockopts);
1918         xt_unregister_target(&arpt_error_target);
1919         xt_unregister_target(&arpt_standard_target);
1920         unregister_pernet_subsys(&arp_tables_net_ops);
1921 }
1922
1923 EXPORT_SYMBOL(arpt_register_table);
1924 EXPORT_SYMBOL(arpt_unregister_table);
1925 EXPORT_SYMBOL(arpt_do_table);
1926
1927 module_init(arp_tables_init);
1928 module_exit(arp_tables_fini);