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