net/ipv4/netfilter/arp_tables.c

   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
  10  *
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13 #include <linux/kernel.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/capability.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/kmod.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/mutex.h>
  24 #include <linux/err.h>
  25 #include <net/compat.h>
  26 #include <net/sock.h>
  27 #include <asm/uaccess.h>
  28
  29 #include <linux/netfilter/x_tables.h>
  30 #include <linux/netfilter_arp/arp_tables.h>
  31 #include "../../netfilter/xt_repldata.h"
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  35 MODULE_DESCRIPTION("arptables core");
  36
  37 /*#define DEBUG_ARP_TABLES*/
  38 /*#define DEBUG_ARP_TABLES_USER*/
  39
  40 #ifdef DEBUG_ARP_TABLES
  41 #define dprintf(format, args...)  printk(format , ## args)
  42 #else
  43 #define dprintf(format, args...)
  44 #endif
  45
  46 #ifdef DEBUG_ARP_TABLES_USER
  47 #define duprintf(format, args...) printk(format , ## args)
  48 #else
  49 #define duprintf(format, args...)
  50 #endif
  51
  52 #ifdef CONFIG_NETFILTER_DEBUG
  53 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  54 #else
  55 #define ARP_NF_ASSERT(x)
  56 #endif
  57
  58 void *arpt_alloc_initial_table(const struct xt_table *info)
  59 {
  60         return xt_alloc_initial_table(arpt, ARPT);
  61 }
  62 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  63
  64 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  65                                       const char *hdr_addr, int len)
  66 {
  67         int i, ret;
  68
  69         if (len > ARPT_DEV_ADDR_LEN_MAX)
  70                 len = ARPT_DEV_ADDR_LEN_MAX;
  71
  72         ret = 0;
  73         for (i = 0; i < len; i++)
  74                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  75
  76         return ret != 0;
  77 }
  78
  79 /*
  80  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  81  * Some arches dont care, unrolling the loop is a win on them.
  82  * For other arches, we only have a 16bit alignement.
  83  */
  84 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  85 {
  86 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  87         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  88 #else
  89         unsigned long ret = 0;
  90         const u16 *a = (const u16 *)_a;
  91         const u16 *b = (const u16 *)_b;
  92         const u16 *mask = (const u16 *)_mask;
  93         int i;
  94
  95         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  96                 ret |= (a[i] ^ b[i]) & mask[i];
  97 #endif
  98         return ret;
  99 }
 100
 101 /* Returns whether packet matches rule or not. */
 102 static inline int arp_packet_match(const struct arphdr *arphdr,
 103                                    struct net_device *dev,
 104                                    const char *indev,
 105                                    const char *outdev,
 106                                    const struct arpt_arp *arpinfo)
 107 {
 108         const char *arpptr = (char *)(arphdr + 1);
 109         const char *src_devaddr, *tgt_devaddr;
 110         __be32 src_ipaddr, tgt_ipaddr;
 111         long ret;
 112
 113 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 114
 115         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 116                   ARPT_INV_ARPOP)) {
 117                 dprintf("ARP operation field mismatch.\n");
 118                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 119                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 120                 return 0;
 121         }
 122
 123         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 124                   ARPT_INV_ARPHRD)) {
 125                 dprintf("ARP hardware address format mismatch.\n");
 126                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 127                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 128                 return 0;
 129         }
 130
 131         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 132                   ARPT_INV_ARPPRO)) {
 133                 dprintf("ARP protocol address format mismatch.\n");
 134                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 135                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 136                 return 0;
 137         }
 138
 139         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 140                   ARPT_INV_ARPHLN)) {
 141                 dprintf("ARP hardware address length mismatch.\n");
 142                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 143                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 144                 return 0;
 145         }
 146
 147         src_devaddr = arpptr;
 148         arpptr += dev->addr_len;
 149         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 150         arpptr += sizeof(u32);
 151         tgt_devaddr = arpptr;
 152         arpptr += dev->addr_len;
 153         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 154
 155         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 156                   ARPT_INV_SRCDEVADDR) ||
 157             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 158                   ARPT_INV_TGTDEVADDR)) {
 159                 dprintf("Source or target device address mismatch.\n");
 160
 161                 return 0;
 162         }
 163
 164         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 165                   ARPT_INV_SRCIP) ||
 166             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 167                   ARPT_INV_TGTIP)) {
 168                 dprintf("Source or target IP address mismatch.\n");
 169
 170                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 171                         &src_ipaddr,
 172                         &arpinfo->smsk.s_addr,
 173                         &arpinfo->src.s_addr,
 174                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 175                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 176                         &tgt_ipaddr,
 177                         &arpinfo->tmsk.s_addr,
 178                         &arpinfo->tgt.s_addr,
 179                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 180                 return 0;
 181         }
 182
 183         /* Look for ifname matches.  */
 184         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 185
 186         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 187                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 188                         indev, arpinfo->iniface,
 189                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 190                 return 0;
 191         }
 192
 193         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 194
 195         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 196                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 197                         outdev, arpinfo->outiface,
 198                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 199                 return 0;
 200         }
 201
 202         return 1;
 203 #undef FWINV
 204 }
 205
 206 static inline int arp_checkentry(const struct arpt_arp *arp)
 207 {
 208         if (arp->flags & ~ARPT_F_MASK) {
 209                 duprintf("Unknown flag bits set: %08X\n",
 210                          arp->flags & ~ARPT_F_MASK);
 211                 return 0;
 212         }
 213         if (arp->invflags & ~ARPT_INV_MASK) {
 214                 duprintf("Unknown invflag bits set: %08X\n",
 215                          arp->invflags & ~ARPT_INV_MASK);
 216                 return 0;
 217         }
 218
 219         return 1;
 220 }
 221
 222 static unsigned int
 223 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 224 {
 225         net_err_ratelimited("arp_tables: error: '%s'\n",
 226                             (const char *)par->targinfo);
 227
 228         return NF_DROP;
 229 }
 230
 231 static inline const struct xt_entry_target *
 232 arpt_get_target_c(const struct arpt_entry *e)
 233 {
 234         return arpt_get_target((struct arpt_entry *)e);
 235 }
 236
 237 static inline struct arpt_entry *
 238 get_entry(const void *base, unsigned int offset)
 239 {
 240         return (struct arpt_entry *)(base + offset);
 241 }
 242
 243 static inline
 244 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 245 {
 246         return (void *)entry + entry->next_offset;
 247 }
 248
 249 unsigned int arpt_do_table(struct sk_buff *skb,
 250                            unsigned int hook,
 251                            const struct nf_hook_state *state,
 252                            struct xt_table *table)
 253 {
 254         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 255         unsigned int verdict = NF_DROP;
 256         const struct arphdr *arp;
 257         struct arpt_entry *e, **jumpstack;
 258         const char *indev, *outdev;
 259         const void *table_base;
 260         unsigned int cpu, stackidx = 0;
 261         const struct xt_table_info *private;
 262         struct xt_action_param acpar;
 263         unsigned int addend;
 264
 265         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 266                 return NF_DROP;
 267
 268         indev = state->in ? state->in->name : nulldevname;
 269         outdev = state->out ? state->out->name : nulldevname;
 270
 271         local_bh_disable();
 272         addend = xt_write_recseq_begin();
 273         private = table->private;
 274         cpu     = smp_processor_id();
 275         /*
 276          * Ensure we load private-> members after we've fetched the base
 277          * pointer.
 278          */
 279         smp_read_barrier_depends();
 280         table_base = private->entries;
 281         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 282
 283         /* No TEE support for arptables, so no need to switch to alternate
 284          * stack.  All targets that reenter must return absolute verdicts.
 285          */
 286         e = get_entry(table_base, private->hook_entry[hook]);
 287
 288         acpar.in      = state->in;
 289         acpar.out     = state->out;
 290         acpar.hooknum = hook;
 291         acpar.family  = NFPROTO_ARP;
 292         acpar.hotdrop = false;
 293
 294         arp = arp_hdr(skb);
 295         do {
 296                 const struct xt_entry_target *t;
 297                 struct xt_counters *counter;
 298
 299                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 300                         e = arpt_next_entry(e);
 301                         continue;
 302                 }
 303
 304                 counter = xt_get_this_cpu_counter(&e->counters);
 305                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 306
 307                 t = arpt_get_target_c(e);
 308
 309                 /* Standard target? */
 310                 if (!t->u.kernel.target->target) {
 311                         int v;
 312
 313                         v = ((struct xt_standard_target *)t)->verdict;
 314                         if (v < 0) {
 315                                 /* Pop from stack? */
 316                                 if (v != XT_RETURN) {
 317                                         verdict = (unsigned int)(-v) - 1;
 318                                         break;
 319                                 }
 320                                 if (stackidx == 0) {
 321                                         e = get_entry(table_base,
 322                                                       private->underflow[hook]);
 323                                 } else {
 324                                         e = jumpstack[--stackidx];
 325                                         e = arpt_next_entry(e);
 326                                 }
 327                                 continue;
 328                         }
 329                         if (table_base + v
 330                             != arpt_next_entry(e)) {
 331                                 jumpstack[stackidx++] = e;
 332                         }
 333
 334                         e = get_entry(table_base, v);
 335                         continue;
 336                 }
 337
 338                 acpar.target   = t->u.kernel.target;
 339                 acpar.targinfo = t->data;
 340                 verdict = t->u.kernel.target->target(skb, &acpar);
 341
 342                 /* Target might have changed stuff. */
 343                 arp = arp_hdr(skb);
 344
 345                 if (verdict == XT_CONTINUE)
 346                         e = arpt_next_entry(e);
 347                 else
 348                         /* Verdict */
 349                         break;
 350         } while (!acpar.hotdrop);
 351         xt_write_recseq_end(addend);
 352         local_bh_enable();
 353
 354         if (acpar.hotdrop)
 355                 return NF_DROP;
 356         else
 357                 return verdict;
 358 }
 359
 360 /* All zeroes == unconditional rule. */
 361 static inline bool unconditional(const struct arpt_arp *arp)
 362 {
 363         static const struct arpt_arp uncond;
 364
 365         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 366 }
 367
 368 /* Figures out from what hook each rule can be called: returns 0 if
 369  * there are loops.  Puts hook bitmask in comefrom.
 370  */
 371 static int mark_source_chains(const struct xt_table_info *newinfo,
 372                               unsigned int valid_hooks, void *entry0)
 373 {
 374         unsigned int hook;
 375
 376         /* No recursion; use packet counter to save back ptrs (reset
 377          * to 0 as we leave), and comefrom to save source hook bitmask.
 378          */
 379         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 380                 unsigned int pos = newinfo->hook_entry[hook];
 381                 struct arpt_entry *e
 382                         = (struct arpt_entry *)(entry0 + pos);
 383
 384                 if (!(valid_hooks & (1 << hook)))
 385                         continue;
 386
 387                 /* Set initial back pointer. */
 388                 e->counters.pcnt = pos;
 389
 390                 for (;;) {
 391                         const struct xt_standard_target *t
 392                                 = (void *)arpt_get_target_c(e);
 393                         int visited = e->comefrom & (1 << hook);
 394
 395                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 396                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 397                                        hook, pos, e->comefrom);
 398                                 return 0;
 399                         }
 400                         e->comefrom
 401                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 402
 403                         /* Unconditional return/END. */
 404                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 405                              (strcmp(t->target.u.user.name,
 406                                      XT_STANDARD_TARGET) == 0) &&
 407                              t->verdict < 0 && unconditional(&e->arp)) ||
 408                             visited) {
 409                                 unsigned int oldpos, size;
 410
 411                                 if ((strcmp(t->target.u.user.name,
 412                                             XT_STANDARD_TARGET) == 0) &&
 413                                     t->verdict < -NF_MAX_VERDICT - 1) {
 414                                         duprintf("mark_source_chains: bad "
 415                                                 "negative verdict (%i)\n",
 416                                                                 t->verdict);
 417                                         return 0;
 418                                 }
 419
 420                                 /* Return: backtrack through the last
 421                                  * big jump.
 422                                  */
 423                                 do {
 424                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 425                                         oldpos = pos;
 426                                         pos = e->counters.pcnt;
 427                                         e->counters.pcnt = 0;
 428
 429                                         /* We're at the start. */
 430                                         if (pos == oldpos)
 431                                                 goto next;
 432
 433                                         e = (struct arpt_entry *)
 434                                                 (entry0 + pos);
 435                                 } while (oldpos == pos + e->next_offset);
 436
 437                                 /* Move along one */
 438                                 size = e->next_offset;
 439                                 e = (struct arpt_entry *)
 440                                         (entry0 + pos + size);
 441                                 e->counters.pcnt = pos;
 442                                 pos += size;
 443                         } else {
 444                                 int newpos = t->verdict;
 445
 446                                 if (strcmp(t->target.u.user.name,
 447                                            XT_STANDARD_TARGET) == 0 &&
 448                                     newpos >= 0) {
 449                                         if (newpos > newinfo->size -
 450                                                 sizeof(struct arpt_entry)) {
 451                                                 duprintf("mark_source_chains: "
 452                                                         "bad verdict (%i)\n",
 453                                                                 newpos);
 454                                                 return 0;
 455                                         }
 456
 457                                         /* This a jump; chase it. */
 458                                         duprintf("Jump rule %u -> %u\n",
 459                                                  pos, newpos);
 460                                 } else {
 461                                         /* ... this is a fallthru */
 462                                         newpos = pos + e->next_offset;
 463                                 }
 464                                 e = (struct arpt_entry *)
 465                                         (entry0 + newpos);
 466                                 e->counters.pcnt = pos;
 467                                 pos = newpos;
 468                         }
 469                 }
 470                 next:
 471                 duprintf("Finished chain %u\n", hook);
 472         }
 473         return 1;
 474 }
 475
 476 static inline int check_entry(const struct arpt_entry *e, const char *name)
 477 {
 478         const struct xt_entry_target *t;
 479
 480         if (!arp_checkentry(&e->arp)) {
 481                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 482                 return -EINVAL;
 483         }
 484
 485         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
 486                 return -EINVAL;
 487
 488         t = arpt_get_target_c(e);
 489         if (e->target_offset + t->u.target_size > e->next_offset)
 490                 return -EINVAL;
 491
 492         return 0;
 493 }
 494
 495 static inline int check_target(struct arpt_entry *e, const char *name)
 496 {
 497         struct xt_entry_target *t = arpt_get_target(e);
 498         int ret;
 499         struct xt_tgchk_param par = {
 500                 .table     = name,
 501                 .entryinfo = e,
 502                 .target    = t->u.kernel.target,
 503                 .targinfo  = t->data,
 504                 .hook_mask = e->comefrom,
 505                 .family    = NFPROTO_ARP,
 506         };
 507
 508         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 509         if (ret < 0) {
 510                 duprintf("arp_tables: check failed for `%s'.\n",
 511                          t->u.kernel.target->name);
 512                 return ret;
 513         }
 514         return 0;
 515 }
 516
 517 static inline int
 518 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 519 {
 520         struct xt_entry_target *t;
 521         struct xt_target *target;
 522         int ret;
 523
 524         ret = check_entry(e, name);
 525         if (ret)
 526                 return ret;
 527
 528         e->counters.pcnt = xt_percpu_counter_alloc();
 529         if (IS_ERR_VALUE(e->counters.pcnt))
 530                 return -ENOMEM;
 531
 532         t = arpt_get_target(e);
 533         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 534                                         t->u.user.revision);
 535         if (IS_ERR(target)) {
 536                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 537                 ret = PTR_ERR(target);
 538                 goto out;
 539         }
 540         t->u.kernel.target = target;
 541
 542         ret = check_target(e, name);
 543         if (ret)
 544                 goto err;
 545         return 0;
 546 err:
 547         module_put(t->u.kernel.target->me);
 548 out:
 549         xt_percpu_counter_free(e->counters.pcnt);
 550
 551         return ret;
 552 }
 553
 554 static bool check_underflow(const struct arpt_entry *e)
 555 {
 556         const struct xt_entry_target *t;
 557         unsigned int verdict;
 558
 559         if (!unconditional(&e->arp))
 560                 return false;
 561         t = arpt_get_target_c(e);
 562         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 563                 return false;
 564         verdict = ((struct xt_standard_target *)t)->verdict;
 565         verdict = -verdict - 1;
 566         return verdict == NF_DROP || verdict == NF_ACCEPT;
 567 }
 568
 569 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 570                                              struct xt_table_info *newinfo,
 571                                              const unsigned char *base,
 572                                              const unsigned char *limit,
 573                                              const unsigned int *hook_entries,
 574                                              const unsigned int *underflows,
 575                                              unsigned int valid_hooks)
 576 {
 577         unsigned int h;
 578
 579         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 580             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 581                 duprintf("Bad offset %p\n", e);
 582                 return -EINVAL;
 583         }
 584
 585         if (e->next_offset
 586             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 587                 duprintf("checking: element %p size %u\n",
 588                          e, e->next_offset);
 589                 return -EINVAL;
 590         }
 591
 592         /* Check hooks & underflows */
 593         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 594                 if (!(valid_hooks & (1 << h)))
 595                         continue;
 596                 if ((unsigned char *)e - base == hook_entries[h])
 597                         newinfo->hook_entry[h] = hook_entries[h];
 598                 if ((unsigned char *)e - base == underflows[h]) {
 599                         if (!check_underflow(e)) {
 600                                 pr_err("Underflows must be unconditional and "
 601                                        "use the STANDARD target with "
 602                                        "ACCEPT/DROP\n");
 603                                 return -EINVAL;
 604                         }
 605                         newinfo->underflow[h] = underflows[h];
 606                 }
 607         }
 608
 609         /* Clear counters and comefrom */
 610         e->counters = ((struct xt_counters) { 0, 0 });
 611         e->comefrom = 0;
 612         return 0;
 613 }
 614
 615 static inline void cleanup_entry(struct arpt_entry *e)
 616 {
 617         struct xt_tgdtor_param par;
 618         struct xt_entry_target *t;
 619
 620         t = arpt_get_target(e);
 621         par.target   = t->u.kernel.target;
 622         par.targinfo = t->data;
 623         par.family   = NFPROTO_ARP;
 624         if (par.target->destroy != NULL)
 625                 par.target->destroy(&par);
 626         module_put(par.target->me);
 627         xt_percpu_counter_free(e->counters.pcnt);
 628 }
 629
 630 /* Checks and translates the user-supplied table segment (held in
 631  * newinfo).
 632  */
 633 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 634                            const struct arpt_replace *repl)
 635 {
 636         struct arpt_entry *iter;
 637         unsigned int i;
 638         int ret = 0;
 639
 640         newinfo->size = repl->size;
 641         newinfo->number = repl->num_entries;
 642
 643         /* Init all hooks to impossible value. */
 644         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 645                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 646                 newinfo->underflow[i] = 0xFFFFFFFF;
 647         }
 648
 649         duprintf("translate_table: size %u\n", newinfo->size);
 650         i = 0;
 651
 652         /* Walk through entries, checking offsets. */
 653         xt_entry_foreach(iter, entry0, newinfo->size) {
 654                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 655                                                  entry0 + repl->size,
 656                                                  repl->hook_entry,
 657                                                  repl->underflow,
 658                                                  repl->valid_hooks);
 659                 if (ret != 0)
 660                         break;
 661                 ++i;
 662                 if (strcmp(arpt_get_target(iter)->u.user.name,
 663                     XT_ERROR_TARGET) == 0)
 664                         ++newinfo->stacksize;
 665         }
 666         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 667         if (ret != 0)
 668                 return ret;
 669
 670         if (i != repl->num_entries) {
 671                 duprintf("translate_table: %u not %u entries\n",
 672                          i, repl->num_entries);
 673                 return -EINVAL;
 674         }
 675
 676         /* Check hooks all assigned */
 677         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 678                 /* Only hooks which are valid */
 679                 if (!(repl->valid_hooks & (1 << i)))
 680                         continue;
 681                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 682                         duprintf("Invalid hook entry %u %u\n",
 683                                  i, repl->hook_entry[i]);
 684                         return -EINVAL;
 685                 }
 686                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 687                         duprintf("Invalid underflow %u %u\n",
 688                                  i, repl->underflow[i]);
 689                         return -EINVAL;
 690                 }
 691         }
 692
 693         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 694                 duprintf("Looping hook\n");
 695                 return -ELOOP;
 696         }
 697
 698         /* Finally, each sanity check must pass */
 699         i = 0;
 700         xt_entry_foreach(iter, entry0, newinfo->size) {
 701                 ret = find_check_entry(iter, repl->name, repl->size);
 702                 if (ret != 0)
 703                         break;
 704                 ++i;
 705         }
 706
 707         if (ret != 0) {
 708                 xt_entry_foreach(iter, entry0, newinfo->size) {
 709                         if (i-- == 0)
 710                                 break;
 711                         cleanup_entry(iter);
 712                 }
 713                 return ret;
 714         }
 715
 716         return ret;
 717 }
 718
 719 static void get_counters(const struct xt_table_info *t,
 720                          struct xt_counters counters[])
 721 {
 722         struct arpt_entry *iter;
 723         unsigned int cpu;
 724         unsigned int i;
 725
 726         for_each_possible_cpu(cpu) {
 727                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 728
 729                 i = 0;
 730                 xt_entry_foreach(iter, t->entries, t->size) {
 731                         struct xt_counters *tmp;
 732                         u64 bcnt, pcnt;
 733                         unsigned int start;
 734
 735                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 736                         do {
 737                                 start = read_seqcount_begin(s);
 738                                 bcnt = tmp->bcnt;
 739                                 pcnt = tmp->pcnt;
 740                         } while (read_seqcount_retry(s, start));
 741
 742                         ADD_COUNTER(counters[i], bcnt, pcnt);
 743                         ++i;
 744                 }
 745         }
 746 }
 747
 748 static struct xt_counters *alloc_counters(const struct xt_table *table)
 749 {
 750         unsigned int countersize;
 751         struct xt_counters *counters;
 752         const struct xt_table_info *private = table->private;
 753
 754         /* We need atomic snapshot of counters: rest doesn't change
 755          * (other than comefrom, which userspace doesn't care
 756          * about).
 757          */
 758         countersize = sizeof(struct xt_counters) * private->number;
 759         counters = vzalloc(countersize);
 760
 761         if (counters == NULL)
 762                 return ERR_PTR(-ENOMEM);
 763
 764         get_counters(private, counters);
 765
 766         return counters;
 767 }
 768
 769 static int copy_entries_to_user(unsigned int total_size,
 770                                 const struct xt_table *table,
 771                                 void __user *userptr)
 772 {
 773         unsigned int off, num;
 774         const struct arpt_entry *e;
 775         struct xt_counters *counters;
 776         struct xt_table_info *private = table->private;
 777         int ret = 0;
 778         void *loc_cpu_entry;
 779
 780         counters = alloc_counters(table);
 781         if (IS_ERR(counters))
 782                 return PTR_ERR(counters);
 783
 784         loc_cpu_entry = private->entries;
 785         /* ... then copy entire thing ... */
 786         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 787                 ret = -EFAULT;
 788                 goto free_counters;
 789         }
 790
 791         /* FIXME: use iterator macros --RR */
 792         /* ... then go back and fix counters and names */
 793         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 794                 const struct xt_entry_target *t;
 795
 796                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 797                 if (copy_to_user(userptr + off
 798                                  + offsetof(struct arpt_entry, counters),
 799                                  &counters[num],
 800                                  sizeof(counters[num])) != 0) {
 801                         ret = -EFAULT;
 802                         goto free_counters;
 803                 }
 804
 805                 t = arpt_get_target_c(e);
 806                 if (copy_to_user(userptr + off + e->target_offset
 807                                  + offsetof(struct xt_entry_target,
 808                                             u.user.name),
 809                                  t->u.kernel.target->name,
 810                                  strlen(t->u.kernel.target->name)+1) != 0) {
 811                         ret = -EFAULT;
 812                         goto free_counters;
 813                 }
 814         }
 815
 816  free_counters:
 817         vfree(counters);
 818         return ret;
 819 }
 820
 821 #ifdef CONFIG_COMPAT
 822 static void compat_standard_from_user(void *dst, const void *src)
 823 {
 824         int v = *(compat_int_t *)src;
 825
 826         if (v > 0)
 827                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 828         memcpy(dst, &v, sizeof(v));
 829 }
 830
 831 static int compat_standard_to_user(void __user *dst, const void *src)
 832 {
 833         compat_int_t cv = *(int *)src;
 834
 835         if (cv > 0)
 836                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 837         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 838 }
 839
 840 static int compat_calc_entry(const struct arpt_entry *e,
 841                              const struct xt_table_info *info,
 842                              const void *base, struct xt_table_info *newinfo)
 843 {
 844         const struct xt_entry_target *t;
 845         unsigned int entry_offset;
 846         int off, i, ret;
 847
 848         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 849         entry_offset = (void *)e - base;
 850
 851         t = arpt_get_target_c(e);
 852         off += xt_compat_target_offset(t->u.kernel.target);
 853         newinfo->size -= off;
 854         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 855         if (ret)
 856                 return ret;
 857
 858         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 859                 if (info->hook_entry[i] &&
 860                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 861                         newinfo->hook_entry[i] -= off;
 862                 if (info->underflow[i] &&
 863                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 864                         newinfo->underflow[i] -= off;
 865         }
 866         return 0;
 867 }
 868
 869 static int compat_table_info(const struct xt_table_info *info,
 870                              struct xt_table_info *newinfo)
 871 {
 872         struct arpt_entry *iter;
 873         const void *loc_cpu_entry;
 874         int ret;
 875
 876         if (!newinfo || !info)
 877                 return -EINVAL;
 878
 879         /* we dont care about newinfo->entries */
 880         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 881         newinfo->initial_entries = 0;
 882         loc_cpu_entry = info->entries;
 883         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 884         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 885                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 886                 if (ret != 0)
 887                         return ret;
 888         }
 889         return 0;
 890 }
 891 #endif
 892
 893 static int get_info(struct net *net, void __user *user,
 894                     const int *len, int compat)
 895 {
 896         char name[XT_TABLE_MAXNAMELEN];
 897         struct xt_table *t;
 898         int ret;
 899
 900         if (*len != sizeof(struct arpt_getinfo)) {
 901                 duprintf("length %u != %Zu\n", *len,
 902                          sizeof(struct arpt_getinfo));
 903                 return -EINVAL;
 904         }
 905
 906         if (copy_from_user(name, user, sizeof(name)) != 0)
 907                 return -EFAULT;
 908
 909         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 910 #ifdef CONFIG_COMPAT
 911         if (compat)
 912                 xt_compat_lock(NFPROTO_ARP);
 913 #endif
 914         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 915                                     "arptable_%s", name);
 916         if (!IS_ERR_OR_NULL(t)) {
 917                 struct arpt_getinfo info;
 918                 const struct xt_table_info *private = t->private;
 919 #ifdef CONFIG_COMPAT
 920                 struct xt_table_info tmp;
 921
 922                 if (compat) {
 923                         ret = compat_table_info(private, &tmp);
 924                         xt_compat_flush_offsets(NFPROTO_ARP);
 925                         private = &tmp;
 926                 }
 927 #endif
 928                 memset(&info, 0, sizeof(info));
 929                 info.valid_hooks = t->valid_hooks;
 930                 memcpy(info.hook_entry, private->hook_entry,
 931                        sizeof(info.hook_entry));
 932                 memcpy(info.underflow, private->underflow,
 933                        sizeof(info.underflow));
 934                 info.num_entries = private->number;
 935                 info.size = private->size;
 936                 strcpy(info.name, name);
 937
 938                 if (copy_to_user(user, &info, *len) != 0)
 939                         ret = -EFAULT;
 940                 else
 941                         ret = 0;
 942                 xt_table_unlock(t);
 943                 module_put(t->me);
 944         } else
 945                 ret = t ? PTR_ERR(t) : -ENOENT;
 946 #ifdef CONFIG_COMPAT
 947         if (compat)
 948                 xt_compat_unlock(NFPROTO_ARP);
 949 #endif
 950         return ret;
 951 }
 952
 953 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 954                        const int *len)
 955 {
 956         int ret;
 957         struct arpt_get_entries get;
 958         struct xt_table *t;
 959
 960         if (*len < sizeof(get)) {
 961                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 962                 return -EINVAL;
 963         }
 964         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 965                 return -EFAULT;
 966         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 967                 duprintf("get_entries: %u != %Zu\n", *len,
 968                          sizeof(struct arpt_get_entries) + get.size);
 969                 return -EINVAL;
 970         }
 971
 972         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 973         if (!IS_ERR_OR_NULL(t)) {
 974                 const struct xt_table_info *private = t->private;
 975
 976                 duprintf("t->private->number = %u\n",
 977                          private->number);
 978                 if (get.size == private->size)
 979                         ret = copy_entries_to_user(private->size,
 980                                                    t, uptr->entrytable);
 981                 else {
 982                         duprintf("get_entries: I've got %u not %u!\n",
 983                                  private->size, get.size);
 984                         ret = -EAGAIN;
 985                 }
 986                 module_put(t->me);
 987                 xt_table_unlock(t);
 988         } else
 989                 ret = t ? PTR_ERR(t) : -ENOENT;
 990
 991         return ret;
 992 }
 993
 994 static int __do_replace(struct net *net, const char *name,
 995                         unsigned int valid_hooks,
 996                         struct xt_table_info *newinfo,
 997                         unsigned int num_counters,
 998                         void __user *counters_ptr)
 999 {
1000         int ret;
1001         struct xt_table *t;
1002         struct xt_table_info *oldinfo;
1003         struct xt_counters *counters;
1004         void *loc_cpu_old_entry;
1005         struct arpt_entry *iter;
1006
1007         ret = 0;
1008         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1009         if (!counters) {
1010                 ret = -ENOMEM;
1011                 goto out;
1012         }
1013
1014         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1015                                     "arptable_%s", name);
1016         if (IS_ERR_OR_NULL(t)) {
1017                 ret = t ? PTR_ERR(t) : -ENOENT;
1018                 goto free_newinfo_counters_untrans;
1019         }
1020
1021         /* You lied! */
1022         if (valid_hooks != t->valid_hooks) {
1023                 duprintf("Valid hook crap: %08X vs %08X\n",
1024                          valid_hooks, t->valid_hooks);
1025                 ret = -EINVAL;
1026                 goto put_module;
1027         }
1028
1029         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1030         if (!oldinfo)
1031                 goto put_module;
1032
1033         /* Update module usage count based on number of rules */
1034         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1035                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1036         if ((oldinfo->number > oldinfo->initial_entries) ||
1037             (newinfo->number <= oldinfo->initial_entries))
1038                 module_put(t->me);
1039         if ((oldinfo->number > oldinfo->initial_entries) &&
1040             (newinfo->number <= oldinfo->initial_entries))
1041                 module_put(t->me);
1042
1043         /* Get the old counters, and synchronize with replace */
1044         get_counters(oldinfo, counters);
1045
1046         /* Decrease module usage counts and free resource */
1047         loc_cpu_old_entry = oldinfo->entries;
1048         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1049                 cleanup_entry(iter);
1050
1051         xt_free_table_info(oldinfo);
1052         if (copy_to_user(counters_ptr, counters,
1053                          sizeof(struct xt_counters) * num_counters) != 0) {
1054                 /* Silent error, can't fail, new table is already in place */
1055                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1056         }
1057         vfree(counters);
1058         xt_table_unlock(t);
1059         return ret;
1060
1061  put_module:
1062         module_put(t->me);
1063         xt_table_unlock(t);
1064  free_newinfo_counters_untrans:
1065         vfree(counters);
1066  out:
1067         return ret;
1068 }
1069
1070 static int do_replace(struct net *net, const void __user *user,
1071                       unsigned int len)
1072 {
1073         int ret;
1074         struct arpt_replace tmp;
1075         struct xt_table_info *newinfo;
1076         void *loc_cpu_entry;
1077         struct arpt_entry *iter;
1078
1079         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1080                 return -EFAULT;
1081
1082         /* overflow check */
1083         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1084                 return -ENOMEM;
1085         if (tmp.num_counters == 0)
1086                 return -EINVAL;
1087
1088         tmp.name[sizeof(tmp.name)-1] = 0;
1089
1090         newinfo = xt_alloc_table_info(tmp.size);
1091         if (!newinfo)
1092                 return -ENOMEM;
1093
1094         loc_cpu_entry = newinfo->entries;
1095         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1096                            tmp.size) != 0) {
1097                 ret = -EFAULT;
1098                 goto free_newinfo;
1099         }
1100
1101         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1102         if (ret != 0)
1103                 goto free_newinfo;
1104
1105         duprintf("arp_tables: Translated table\n");
1106
1107         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1108                            tmp.num_counters, tmp.counters);
1109         if (ret)
1110                 goto free_newinfo_untrans;
1111         return 0;
1112
1113  free_newinfo_untrans:
1114         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1115                 cleanup_entry(iter);
1116  free_newinfo:
1117         xt_free_table_info(newinfo);
1118         return ret;
1119 }
1120
1121 static int do_add_counters(struct net *net, const void __user *user,
1122                            unsigned int len, int compat)
1123 {
1124         unsigned int i;
1125         struct xt_counters_info tmp;
1126         struct xt_counters *paddc;
1127         unsigned int num_counters;
1128         const char *name;
1129         int size;
1130         void *ptmp;
1131         struct xt_table *t;
1132         const struct xt_table_info *private;
1133         int ret = 0;
1134         struct arpt_entry *iter;
1135         unsigned int addend;
1136 #ifdef CONFIG_COMPAT
1137         struct compat_xt_counters_info compat_tmp;
1138
1139         if (compat) {
1140                 ptmp = &compat_tmp;
1141                 size = sizeof(struct compat_xt_counters_info);
1142         } else
1143 #endif
1144         {
1145                 ptmp = &tmp;
1146                 size = sizeof(struct xt_counters_info);
1147         }
1148
1149         if (copy_from_user(ptmp, user, size) != 0)
1150                 return -EFAULT;
1151
1152 #ifdef CONFIG_COMPAT
1153         if (compat) {
1154                 num_counters = compat_tmp.num_counters;
1155                 name = compat_tmp.name;
1156         } else
1157 #endif
1158         {
1159                 num_counters = tmp.num_counters;
1160                 name = tmp.name;
1161         }
1162
1163         if (len != size + num_counters * sizeof(struct xt_counters))
1164                 return -EINVAL;
1165
1166         paddc = vmalloc(len - size);
1167         if (!paddc)
1168                 return -ENOMEM;
1169
1170         if (copy_from_user(paddc, user + size, len - size) != 0) {
1171                 ret = -EFAULT;
1172                 goto free;
1173         }
1174
1175         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1176         if (IS_ERR_OR_NULL(t)) {
1177                 ret = t ? PTR_ERR(t) : -ENOENT;
1178                 goto free;
1179         }
1180
1181         local_bh_disable();
1182         private = t->private;
1183         if (private->number != num_counters) {
1184                 ret = -EINVAL;
1185                 goto unlock_up_free;
1186         }
1187
1188         i = 0;
1189
1190         addend = xt_write_recseq_begin();
1191         xt_entry_foreach(iter,  private->entries, private->size) {
1192                 struct xt_counters *tmp;
1193
1194                 tmp = xt_get_this_cpu_counter(&iter->counters);
1195                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1196                 ++i;
1197         }
1198         xt_write_recseq_end(addend);
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 xt_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 xt_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 xt_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         xt_compat_init_offsets(NFPROTO_ARP, number);
1358         /* Walk through entries, checking offsets. */
1359         xt_entry_foreach(iter0, entry0, total_size) {
1360                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1361                                                         entry0,
1362                                                         entry0 + total_size,
1363                                                         hook_entries,
1364                                                         underflows,
1365                                                         name);
1366                 if (ret != 0)
1367                         goto out_unlock;
1368                 ++j;
1369         }
1370
1371         ret = -EINVAL;
1372         if (j != number) {
1373                 duprintf("translate_compat_table: %u not %u entries\n",
1374                          j, number);
1375                 goto out_unlock;
1376         }
1377
1378         /* Check hooks all assigned */
1379         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1380                 /* Only hooks which are valid */
1381                 if (!(valid_hooks & (1 << i)))
1382                         continue;
1383                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1384                         duprintf("Invalid hook entry %u %u\n",
1385                                  i, hook_entries[i]);
1386                         goto out_unlock;
1387                 }
1388                 if (info->underflow[i] == 0xFFFFFFFF) {
1389                         duprintf("Invalid underflow %u %u\n",
1390                                  i, underflows[i]);
1391                         goto out_unlock;
1392                 }
1393         }
1394
1395         ret = -ENOMEM;
1396         newinfo = xt_alloc_table_info(size);
1397         if (!newinfo)
1398                 goto out_unlock;
1399
1400         newinfo->number = number;
1401         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1402                 newinfo->hook_entry[i] = info->hook_entry[i];
1403                 newinfo->underflow[i] = info->underflow[i];
1404         }
1405         entry1 = newinfo->entries;
1406         pos = entry1;
1407         size = total_size;
1408         xt_entry_foreach(iter0, entry0, total_size) {
1409                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1410                                                   name, newinfo, entry1);
1411                 if (ret != 0)
1412                         break;
1413         }
1414         xt_compat_flush_offsets(NFPROTO_ARP);
1415         xt_compat_unlock(NFPROTO_ARP);
1416         if (ret)
1417                 goto free_newinfo;
1418
1419         ret = -ELOOP;
1420         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1421                 goto free_newinfo;
1422
1423         i = 0;
1424         xt_entry_foreach(iter1, entry1, newinfo->size) {
1425                 iter1->counters.pcnt = xt_percpu_counter_alloc();
1426                 if (IS_ERR_VALUE(iter1->counters.pcnt)) {
1427                         ret = -ENOMEM;
1428                         break;
1429                 }
1430
1431                 ret = check_target(iter1, name);
1432                 if (ret != 0) {
1433                         xt_percpu_counter_free(iter1->counters.pcnt);
1434                         break;
1435                 }
1436                 ++i;
1437                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1438                     XT_ERROR_TARGET) == 0)
1439                         ++newinfo->stacksize;
1440         }
1441         if (ret) {
1442                 /*
1443                  * The first i matches need cleanup_entry (calls ->destroy)
1444                  * because they had called ->check already. The other j-i
1445                  * entries need only release.
1446                  */
1447                 int skip = i;
1448                 j -= i;
1449                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1450                         if (skip-- > 0)
1451                                 continue;
1452                         if (j-- == 0)
1453                                 break;
1454                         compat_release_entry(iter0);
1455                 }
1456                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1457                         if (i-- == 0)
1458                                 break;
1459                         cleanup_entry(iter1);
1460                 }
1461                 xt_free_table_info(newinfo);
1462                 return ret;
1463         }
1464
1465         *pinfo = newinfo;
1466         *pentry0 = entry1;
1467         xt_free_table_info(info);
1468         return 0;
1469
1470 free_newinfo:
1471         xt_free_table_info(newinfo);
1472 out:
1473         xt_entry_foreach(iter0, entry0, total_size) {
1474                 if (j-- == 0)
1475                         break;
1476                 compat_release_entry(iter0);
1477         }
1478         return ret;
1479 out_unlock:
1480         xt_compat_flush_offsets(NFPROTO_ARP);
1481         xt_compat_unlock(NFPROTO_ARP);
1482         goto out;
1483 }
1484
1485 struct compat_arpt_replace {
1486         char                            name[XT_TABLE_MAXNAMELEN];
1487         u32                             valid_hooks;
1488         u32                             num_entries;
1489         u32                             size;
1490         u32                             hook_entry[NF_ARP_NUMHOOKS];
1491         u32                             underflow[NF_ARP_NUMHOOKS];
1492         u32                             num_counters;
1493         compat_uptr_t                   counters;
1494         struct compat_arpt_entry        entries[0];
1495 };
1496
1497 static int compat_do_replace(struct net *net, void __user *user,
1498                              unsigned int len)
1499 {
1500         int ret;
1501         struct compat_arpt_replace tmp;
1502         struct xt_table_info *newinfo;
1503         void *loc_cpu_entry;
1504         struct arpt_entry *iter;
1505
1506         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1507                 return -EFAULT;
1508
1509         /* overflow check */
1510         if (tmp.size >= INT_MAX / num_possible_cpus())
1511                 return -ENOMEM;
1512         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1513                 return -ENOMEM;
1514         if (tmp.num_counters == 0)
1515                 return -EINVAL;
1516
1517         tmp.name[sizeof(tmp.name)-1] = 0;
1518
1519         newinfo = xt_alloc_table_info(tmp.size);
1520         if (!newinfo)
1521                 return -ENOMEM;
1522
1523         loc_cpu_entry = newinfo->entries;
1524         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1525                 ret = -EFAULT;
1526                 goto free_newinfo;
1527         }
1528
1529         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1530                                      &newinfo, &loc_cpu_entry, tmp.size,
1531                                      tmp.num_entries, tmp.hook_entry,
1532                                      tmp.underflow);
1533         if (ret != 0)
1534                 goto free_newinfo;
1535
1536         duprintf("compat_do_replace: Translated table\n");
1537
1538         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1539                            tmp.num_counters, compat_ptr(tmp.counters));
1540         if (ret)
1541                 goto free_newinfo_untrans;
1542         return 0;
1543
1544  free_newinfo_untrans:
1545         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1546                 cleanup_entry(iter);
1547  free_newinfo:
1548         xt_free_table_info(newinfo);
1549         return ret;
1550 }
1551
1552 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1553                                   unsigned int len)
1554 {
1555         int ret;
1556
1557         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1558                 return -EPERM;
1559
1560         switch (cmd) {
1561         case ARPT_SO_SET_REPLACE:
1562                 ret = compat_do_replace(sock_net(sk), user, len);
1563                 break;
1564
1565         case ARPT_SO_SET_ADD_COUNTERS:
1566                 ret = do_add_counters(sock_net(sk), user, len, 1);
1567                 break;
1568
1569         default:
1570                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1571                 ret = -EINVAL;
1572         }
1573
1574         return ret;
1575 }
1576
1577 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1578                                      compat_uint_t *size,
1579                                      struct xt_counters *counters,
1580                                      unsigned int i)
1581 {
1582         struct xt_entry_target *t;
1583         struct compat_arpt_entry __user *ce;
1584         u_int16_t target_offset, next_offset;
1585         compat_uint_t origsize;
1586         int ret;
1587
1588         origsize = *size;
1589         ce = (struct compat_arpt_entry __user *)*dstptr;
1590         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1591             copy_to_user(&ce->counters, &counters[i],
1592             sizeof(counters[i])) != 0)
1593                 return -EFAULT;
1594
1595         *dstptr += sizeof(struct compat_arpt_entry);
1596         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1597
1598         target_offset = e->target_offset - (origsize - *size);
1599
1600         t = arpt_get_target(e);
1601         ret = xt_compat_target_to_user(t, dstptr, size);
1602         if (ret)
1603                 return ret;
1604         next_offset = e->next_offset - (origsize - *size);
1605         if (put_user(target_offset, &ce->target_offset) != 0 ||
1606             put_user(next_offset, &ce->next_offset) != 0)
1607                 return -EFAULT;
1608         return 0;
1609 }
1610
1611 static int compat_copy_entries_to_user(unsigned int total_size,
1612                                        struct xt_table *table,
1613                                        void __user *userptr)
1614 {
1615         struct xt_counters *counters;
1616         const struct xt_table_info *private = table->private;
1617         void __user *pos;
1618         unsigned int size;
1619         int ret = 0;
1620         unsigned int i = 0;
1621         struct arpt_entry *iter;
1622
1623         counters = alloc_counters(table);
1624         if (IS_ERR(counters))
1625                 return PTR_ERR(counters);
1626
1627         pos = userptr;
1628         size = total_size;
1629         xt_entry_foreach(iter, private->entries, total_size) {
1630                 ret = compat_copy_entry_to_user(iter, &pos,
1631                                                 &size, counters, i++);
1632                 if (ret != 0)
1633                         break;
1634         }
1635         vfree(counters);
1636         return ret;
1637 }
1638
1639 struct compat_arpt_get_entries {
1640         char name[XT_TABLE_MAXNAMELEN];
1641         compat_uint_t size;
1642         struct compat_arpt_entry entrytable[0];
1643 };
1644
1645 static int compat_get_entries(struct net *net,
1646                               struct compat_arpt_get_entries __user *uptr,
1647                               int *len)
1648 {
1649         int ret;
1650         struct compat_arpt_get_entries get;
1651         struct xt_table *t;
1652
1653         if (*len < sizeof(get)) {
1654                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1655                 return -EINVAL;
1656         }
1657         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1658                 return -EFAULT;
1659         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1660                 duprintf("compat_get_entries: %u != %zu\n",
1661                          *len, sizeof(get) + get.size);
1662                 return -EINVAL;
1663         }
1664
1665         xt_compat_lock(NFPROTO_ARP);
1666         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1667         if (!IS_ERR_OR_NULL(t)) {
1668                 const struct xt_table_info *private = t->private;
1669                 struct xt_table_info info;
1670
1671                 duprintf("t->private->number = %u\n", private->number);
1672                 ret = compat_table_info(private, &info);
1673                 if (!ret && get.size == info.size) {
1674                         ret = compat_copy_entries_to_user(private->size,
1675                                                           t, uptr->entrytable);
1676                 } else if (!ret) {
1677                         duprintf("compat_get_entries: I've got %u not %u!\n",
1678                                  private->size, get.size);
1679                         ret = -EAGAIN;
1680                 }
1681                 xt_compat_flush_offsets(NFPROTO_ARP);
1682                 module_put(t->me);
1683                 xt_table_unlock(t);
1684         } else
1685                 ret = t ? PTR_ERR(t) : -ENOENT;
1686
1687         xt_compat_unlock(NFPROTO_ARP);
1688         return ret;
1689 }
1690
1691 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1692
1693 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1694                                   int *len)
1695 {
1696         int ret;
1697
1698         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1699                 return -EPERM;
1700
1701         switch (cmd) {
1702         case ARPT_SO_GET_INFO:
1703                 ret = get_info(sock_net(sk), user, len, 1);
1704                 break;
1705         case ARPT_SO_GET_ENTRIES:
1706                 ret = compat_get_entries(sock_net(sk), user, len);
1707                 break;
1708         default:
1709                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1710         }
1711         return ret;
1712 }
1713 #endif
1714
1715 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1716 {
1717         int ret;
1718
1719         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1720                 return -EPERM;
1721
1722         switch (cmd) {
1723         case ARPT_SO_SET_REPLACE:
1724                 ret = do_replace(sock_net(sk), user, len);
1725                 break;
1726
1727         case ARPT_SO_SET_ADD_COUNTERS:
1728                 ret = do_add_counters(sock_net(sk), user, len, 0);
1729                 break;
1730
1731         default:
1732                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1733                 ret = -EINVAL;
1734         }
1735
1736         return ret;
1737 }
1738
1739 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1740 {
1741         int ret;
1742
1743         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1744                 return -EPERM;
1745
1746         switch (cmd) {
1747         case ARPT_SO_GET_INFO:
1748                 ret = get_info(sock_net(sk), user, len, 0);
1749                 break;
1750
1751         case ARPT_SO_GET_ENTRIES:
1752                 ret = get_entries(sock_net(sk), user, len);
1753                 break;
1754
1755         case ARPT_SO_GET_REVISION_TARGET: {
1756                 struct xt_get_revision rev;
1757
1758                 if (*len != sizeof(rev)) {
1759                         ret = -EINVAL;
1760                         break;
1761                 }
1762                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1763                         ret = -EFAULT;
1764                         break;
1765                 }
1766                 rev.name[sizeof(rev.name)-1] = 0;
1767
1768                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1769                                                          rev.revision, 1, &ret),
1770                                         "arpt_%s", rev.name);
1771                 break;
1772         }
1773
1774         default:
1775                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1776                 ret = -EINVAL;
1777         }
1778
1779         return ret;
1780 }
1781
1782 struct xt_table *arpt_register_table(struct net *net,
1783                                      const struct xt_table *table,
1784                                      const struct arpt_replace *repl)
1785 {
1786         int ret;
1787         struct xt_table_info *newinfo;
1788         struct xt_table_info bootstrap = {0};
1789         void *loc_cpu_entry;
1790         struct xt_table *new_table;
1791
1792         newinfo = xt_alloc_table_info(repl->size);
1793         if (!newinfo) {
1794                 ret = -ENOMEM;
1795                 goto out;
1796         }
1797
1798         loc_cpu_entry = newinfo->entries;
1799         memcpy(loc_cpu_entry, repl->entries, repl->size);
1800
1801         ret = translate_table(newinfo, loc_cpu_entry, repl);
1802         duprintf("arpt_register_table: translate table gives %d\n", ret);
1803         if (ret != 0)
1804                 goto out_free;
1805
1806         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1807         if (IS_ERR(new_table)) {
1808                 ret = PTR_ERR(new_table);
1809                 goto out_free;
1810         }
1811         return new_table;
1812
1813 out_free:
1814         xt_free_table_info(newinfo);
1815 out:
1816         return ERR_PTR(ret);
1817 }
1818
1819 void arpt_unregister_table(struct xt_table *table)
1820 {
1821         struct xt_table_info *private;
1822         void *loc_cpu_entry;
1823         struct module *table_owner = table->me;
1824         struct arpt_entry *iter;
1825
1826         private = xt_unregister_table(table);
1827
1828         /* Decrease module usage counts and free resources */
1829         loc_cpu_entry = private->entries;
1830         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1831                 cleanup_entry(iter);
1832         if (private->number > private->initial_entries)
1833                 module_put(table_owner);
1834         xt_free_table_info(private);
1835 }
1836
1837 /* The built-in targets: standard (NULL) and error. */
1838 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1839         {
1840                 .name             = XT_STANDARD_TARGET,
1841                 .targetsize       = sizeof(int),
1842                 .family           = NFPROTO_ARP,
1843 #ifdef CONFIG_COMPAT
1844                 .compatsize       = sizeof(compat_int_t),
1845                 .compat_from_user = compat_standard_from_user,
1846                 .compat_to_user   = compat_standard_to_user,
1847 #endif
1848         },
1849         {
1850                 .name             = XT_ERROR_TARGET,
1851                 .target           = arpt_error,
1852                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1853                 .family           = NFPROTO_ARP,
1854         },
1855 };
1856
1857 static struct nf_sockopt_ops arpt_sockopts = {
1858         .pf             = PF_INET,
1859         .set_optmin     = ARPT_BASE_CTL,
1860         .set_optmax     = ARPT_SO_SET_MAX+1,
1861         .set            = do_arpt_set_ctl,
1862 #ifdef CONFIG_COMPAT
1863         .compat_set     = compat_do_arpt_set_ctl,
1864 #endif
1865         .get_optmin     = ARPT_BASE_CTL,
1866         .get_optmax     = ARPT_SO_GET_MAX+1,
1867         .get            = do_arpt_get_ctl,
1868 #ifdef CONFIG_COMPAT
1869         .compat_get     = compat_do_arpt_get_ctl,
1870 #endif
1871         .owner          = THIS_MODULE,
1872 };
1873
1874 static int __net_init arp_tables_net_init(struct net *net)
1875 {
1876         return xt_proto_init(net, NFPROTO_ARP);
1877 }
1878
1879 static void __net_exit arp_tables_net_exit(struct net *net)
1880 {
1881         xt_proto_fini(net, NFPROTO_ARP);
1882 }
1883
1884 static struct pernet_operations arp_tables_net_ops = {
1885         .init = arp_tables_net_init,
1886         .exit = arp_tables_net_exit,
1887 };
1888
1889 static int __init arp_tables_init(void)
1890 {
1891         int ret;
1892
1893         ret = register_pernet_subsys(&arp_tables_net_ops);
1894         if (ret < 0)
1895                 goto err1;
1896
1897         /* No one else will be downing sem now, so we won't sleep */
1898         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1899         if (ret < 0)
1900                 goto err2;
1901
1902         /* Register setsockopt */
1903         ret = nf_register_sockopt(&arpt_sockopts);
1904         if (ret < 0)
1905                 goto err4;
1906
1907         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1908         return 0;
1909
1910 err4:
1911         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1912 err2:
1913         unregister_pernet_subsys(&arp_tables_net_ops);
1914 err1:
1915         return ret;
1916 }
1917
1918 static void __exit arp_tables_fini(void)
1919 {
1920         nf_unregister_sockopt(&arpt_sockopts);
1921         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1922         unregister_pernet_subsys(&arp_tables_net_ops);
1923 }
1924
1925 EXPORT_SYMBOL(arpt_register_table);
1926 EXPORT_SYMBOL(arpt_unregister_table);
1927 EXPORT_SYMBOL(arpt_do_table);
1928
1929 module_init(arp_tables_init);
1930 module_exit(arp_tables_fini);