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