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   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  *
  10  */
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/capability.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/kmod.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/mutex.h>
  23 #include <linux/err.h>
  24 #include <net/compat.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter_arp/arp_tables.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  33 MODULE_DESCRIPTION("arptables core");
  34
  35 /*#define DEBUG_ARP_TABLES*/
  36 /*#define DEBUG_ARP_TABLES_USER*/
  37
  38 #ifdef DEBUG_ARP_TABLES
  39 #define dprintf(format, args...)  printk(format , ## args)
  40 #else
  41 #define dprintf(format, args...)
  42 #endif
  43
  44 #ifdef DEBUG_ARP_TABLES_USER
  45 #define duprintf(format, args...) printk(format , ## args)
  46 #else
  47 #define duprintf(format, args...)
  48 #endif
  49
  50 #ifdef CONFIG_NETFILTER_DEBUG
  51 #define ARP_NF_ASSERT(x)                                        \
  52 do {                                                            \
  53         if (!(x))                                               \
  54                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  55                        __func__, __FILE__, __LINE__);   \
  56 } while(0)
  57 #else
  58 #define ARP_NF_ASSERT(x)
  59 #endif
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       const char *hdr_addr, int len)
  63 {
  64         int i, ret;
  65
  66         if (len > ARPT_DEV_ADDR_LEN_MAX)
  67                 len = ARPT_DEV_ADDR_LEN_MAX;
  68
  69         ret = 0;
  70         for (i = 0; i < len; i++)
  71                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  72
  73         return (ret != 0);
  74 }
  75
  76 /*
  77  * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  78  * Some arches dont care, unrolling the loop is a win on them.
  79  * For other arches, we only have a 16bit alignement.
  80  */
  81 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  82 {
  83 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  84         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  85 #else
  86         unsigned long ret = 0;
  87         const u16 *a = (const u16 *)_a;
  88         const u16 *b = (const u16 *)_b;
  89         const u16 *mask = (const u16 *)_mask;
  90         int i;
  91
  92         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  93                 ret |= (a[i] ^ b[i]) & mask[i];
  94 #endif
  95         return ret;
  96 }
  97
  98 /* Returns whether packet matches rule or not. */
  99 static inline int arp_packet_match(const struct arphdr *arphdr,
 100                                    struct net_device *dev,
 101                                    const char *indev,
 102                                    const char *outdev,
 103                                    const struct arpt_arp *arpinfo)
 104 {
 105         const char *arpptr = (char *)(arphdr + 1);
 106         const char *src_devaddr, *tgt_devaddr;
 107         __be32 src_ipaddr, tgt_ipaddr;
 108         long ret;
 109
 110 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 111
 112         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 113                   ARPT_INV_ARPOP)) {
 114                 dprintf("ARP operation field mismatch.\n");
 115                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 116                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 117                 return 0;
 118         }
 119
 120         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 121                   ARPT_INV_ARPHRD)) {
 122                 dprintf("ARP hardware address format mismatch.\n");
 123                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 124                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 125                 return 0;
 126         }
 127
 128         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 129                   ARPT_INV_ARPPRO)) {
 130                 dprintf("ARP protocol address format mismatch.\n");
 131                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 132                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 133                 return 0;
 134         }
 135
 136         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 137                   ARPT_INV_ARPHLN)) {
 138                 dprintf("ARP hardware address length mismatch.\n");
 139                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 140                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 141                 return 0;
 142         }
 143
 144         src_devaddr = arpptr;
 145         arpptr += dev->addr_len;
 146         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 147         arpptr += sizeof(u32);
 148         tgt_devaddr = arpptr;
 149         arpptr += dev->addr_len;
 150         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 151
 152         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 153                   ARPT_INV_SRCDEVADDR) ||
 154             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 155                   ARPT_INV_TGTDEVADDR)) {
 156                 dprintf("Source or target device address mismatch.\n");
 157
 158                 return 0;
 159         }
 160
 161         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 162                   ARPT_INV_SRCIP) ||
 163             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 164                   ARPT_INV_TGTIP)) {
 165                 dprintf("Source or target IP address mismatch.\n");
 166
 167                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 168                         &src_ipaddr,
 169                         &arpinfo->smsk.s_addr,
 170                         &arpinfo->src.s_addr,
 171                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 172                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 173                         &tgt_ipaddr,
 174                         &arpinfo->tmsk.s_addr,
 175                         &arpinfo->tgt.s_addr,
 176                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 177                 return 0;
 178         }
 179
 180         /* Look for ifname matches.  */
 181         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 182
 183         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 184                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 185                         indev, arpinfo->iniface,
 186                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 187                 return 0;
 188         }
 189
 190         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 191
 192         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 193                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 194                         outdev, arpinfo->outiface,
 195                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 196                 return 0;
 197         }
 198
 199         return 1;
 200 #undef FWINV
 201 }
 202
 203 static inline int arp_checkentry(const struct arpt_arp *arp)
 204 {
 205         if (arp->flags & ~ARPT_F_MASK) {
 206                 duprintf("Unknown flag bits set: %08X\n",
 207                          arp->flags & ~ARPT_F_MASK);
 208                 return 0;
 209         }
 210         if (arp->invflags & ~ARPT_INV_MASK) {
 211                 duprintf("Unknown invflag bits set: %08X\n",
 212                          arp->invflags & ~ARPT_INV_MASK);
 213                 return 0;
 214         }
 215
 216         return 1;
 217 }
 218
 219 static unsigned int
 220 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 221 {
 222         if (net_ratelimit())
 223                 printk("arp_tables: error: '%s'\n",
 224                        (const char *)par->targinfo);
 225
 226         return NF_DROP;
 227 }
 228
 229 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 230 {
 231         return (struct arpt_entry *)(base + offset);
 232 }
 233
 234 static inline __pure
 235 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 236 {
 237         return (void *)entry + entry->next_offset;
 238 }
 239
 240 unsigned int arpt_do_table(struct sk_buff *skb,
 241                            unsigned int hook,
 242                            const struct net_device *in,
 243                            const struct net_device *out,
 244                            struct xt_table *table)
 245 {
 246         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 247         unsigned int verdict = NF_DROP;
 248         const struct arphdr *arp;
 249         bool hotdrop = false;
 250         struct arpt_entry *e, *back;
 251         const char *indev, *outdev;
 252         void *table_base;
 253         const struct xt_table_info *private;
 254         struct xt_target_param tgpar;
 255
 256         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 257                 return NF_DROP;
 258
 259         indev = in ? in->name : nulldevname;
 260         outdev = out ? out->name : nulldevname;
 261
 262         xt_info_rdlock_bh();
 263         private = table->private;
 264         table_base = private->entries[smp_processor_id()];
 265
 266         e = get_entry(table_base, private->hook_entry[hook]);
 267         back = get_entry(table_base, private->underflow[hook]);
 268
 269         tgpar.in      = in;
 270         tgpar.out     = out;
 271         tgpar.hooknum = hook;
 272         tgpar.family  = NFPROTO_ARP;
 273
 274         arp = arp_hdr(skb);
 275         do {
 276                 struct arpt_entry_target *t;
 277                 int hdr_len;
 278
 279                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 280                         e = arpt_next_entry(e);
 281                         continue;
 282                 }
 283
 284                 hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 285                         (2 * skb->dev->addr_len);
 286                 ADD_COUNTER(e->counters, hdr_len, 1);
 287
 288                 t = arpt_get_target(e);
 289
 290                 /* Standard target? */
 291                 if (!t->u.kernel.target->target) {
 292                         int v;
 293
 294                         v = ((struct arpt_standard_target *)t)->verdict;
 295                         if (v < 0) {
 296                                 /* Pop from stack? */
 297                                 if (v != ARPT_RETURN) {
 298                                         verdict = (unsigned)(-v) - 1;
 299                                         break;
 300                                 }
 301                                 e = back;
 302                                 back = get_entry(table_base, back->comefrom);
 303                                 continue;
 304                         }
 305                         if (table_base + v
 306                             != arpt_next_entry(e)) {
 307                                 /* Save old back ptr in next entry */
 308                                 struct arpt_entry *next = arpt_next_entry(e);
 309                                 next->comefrom = (void *)back - table_base;
 310
 311                                 /* set back pointer to next entry */
 312                                 back = next;
 313                         }
 314
 315                         e = get_entry(table_base, v);
 316                         continue;
 317                 }
 318
 319                 /* Targets which reenter must return
 320                  * abs. verdicts
 321                  */
 322                 tgpar.target   = t->u.kernel.target;
 323                 tgpar.targinfo = t->data;
 324                 verdict = t->u.kernel.target->target(skb, &tgpar);
 325
 326                 /* Target might have changed stuff. */
 327                 arp = arp_hdr(skb);
 328
 329                 if (verdict == ARPT_CONTINUE)
 330                         e = arpt_next_entry(e);
 331                 else
 332                         /* Verdict */
 333                         break;
 334         } while (!hotdrop);
 335         xt_info_rdunlock_bh();
 336
 337         if (hotdrop)
 338                 return NF_DROP;
 339         else
 340                 return verdict;
 341 }
 342
 343 /* All zeroes == unconditional rule. */
 344 static inline bool unconditional(const struct arpt_arp *arp)
 345 {
 346         static const struct arpt_arp uncond;
 347
 348         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 349 }
 350
 351 /* Figures out from what hook each rule can be called: returns 0 if
 352  * there are loops.  Puts hook bitmask in comefrom.
 353  */
 354 static int mark_source_chains(struct xt_table_info *newinfo,
 355                               unsigned int valid_hooks, void *entry0)
 356 {
 357         unsigned int hook;
 358
 359         /* No recursion; use packet counter to save back ptrs (reset
 360          * to 0 as we leave), and comefrom to save source hook bitmask.
 361          */
 362         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 363                 unsigned int pos = newinfo->hook_entry[hook];
 364                 struct arpt_entry *e
 365                         = (struct arpt_entry *)(entry0 + pos);
 366
 367                 if (!(valid_hooks & (1 << hook)))
 368                         continue;
 369
 370                 /* Set initial back pointer. */
 371                 e->counters.pcnt = pos;
 372
 373                 for (;;) {
 374                         const struct arpt_standard_target *t
 375                                 = (void *)arpt_get_target(e);
 376                         int visited = e->comefrom & (1 << hook);
 377
 378                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 379                                 printk("arptables: loop hook %u pos %u %08X.\n",
 380                                        hook, pos, e->comefrom);
 381                                 return 0;
 382                         }
 383                         e->comefrom
 384                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 385
 386                         /* Unconditional return/END. */
 387                         if ((e->target_offset == sizeof(struct arpt_entry)
 388                             && (strcmp(t->target.u.user.name,
 389                                        ARPT_STANDARD_TARGET) == 0)
 390                             && t->verdict < 0
 391                             && unconditional(&e->arp)) || visited) {
 392                                 unsigned int oldpos, size;
 393
 394                                 if ((strcmp(t->target.u.user.name,
 395                                             ARPT_STANDARD_TARGET) == 0) &&
 396                                     t->verdict < -NF_MAX_VERDICT - 1) {
 397                                         duprintf("mark_source_chains: bad "
 398                                                 "negative verdict (%i)\n",
 399                                                                 t->verdict);
 400                                         return 0;
 401                                 }
 402
 403                                 /* Return: backtrack through the last
 404                                  * big jump.
 405                                  */
 406                                 do {
 407                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 408                                         oldpos = pos;
 409                                         pos = e->counters.pcnt;
 410                                         e->counters.pcnt = 0;
 411
 412                                         /* We're at the start. */
 413                                         if (pos == oldpos)
 414                                                 goto next;
 415
 416                                         e = (struct arpt_entry *)
 417                                                 (entry0 + pos);
 418                                 } while (oldpos == pos + e->next_offset);
 419
 420                                 /* Move along one */
 421                                 size = e->next_offset;
 422                                 e = (struct arpt_entry *)
 423                                         (entry0 + pos + size);
 424                                 e->counters.pcnt = pos;
 425                                 pos += size;
 426                         } else {
 427                                 int newpos = t->verdict;
 428
 429                                 if (strcmp(t->target.u.user.name,
 430                                            ARPT_STANDARD_TARGET) == 0
 431                                     && newpos >= 0) {
 432                                         if (newpos > newinfo->size -
 433                                                 sizeof(struct arpt_entry)) {
 434                                                 duprintf("mark_source_chains: "
 435                                                         "bad verdict (%i)\n",
 436                                                                 newpos);
 437                                                 return 0;
 438                                         }
 439
 440                                         /* This a jump; chase it. */
 441                                         duprintf("Jump rule %u -> %u\n",
 442                                                  pos, newpos);
 443                                 } else {
 444                                         /* ... this is a fallthru */
 445                                         newpos = pos + e->next_offset;
 446                                 }
 447                                 e = (struct arpt_entry *)
 448                                         (entry0 + newpos);
 449                                 e->counters.pcnt = pos;
 450                                 pos = newpos;
 451                         }
 452                 }
 453                 next:
 454                 duprintf("Finished chain %u\n", hook);
 455         }
 456         return 1;
 457 }
 458
 459 static inline int check_entry(struct arpt_entry *e, const char *name)
 460 {
 461         const struct arpt_entry_target *t;
 462
 463         if (!arp_checkentry(&e->arp)) {
 464                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 465                 return -EINVAL;
 466         }
 467
 468         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 469                 return -EINVAL;
 470
 471         t = arpt_get_target(e);
 472         if (e->target_offset + t->u.target_size > e->next_offset)
 473                 return -EINVAL;
 474
 475         return 0;
 476 }
 477
 478 static inline int check_target(struct arpt_entry *e, const char *name)
 479 {
 480         struct arpt_entry_target *t = arpt_get_target(e);
 481         int ret;
 482         struct xt_tgchk_param par = {
 483                 .table     = name,
 484                 .entryinfo = e,
 485                 .target    = t->u.kernel.target,
 486                 .targinfo  = t->data,
 487                 .hook_mask = e->comefrom,
 488                 .family    = NFPROTO_ARP,
 489         };
 490
 491         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 492         if (ret < 0) {
 493                 duprintf("arp_tables: check failed for `%s'.\n",
 494                          t->u.kernel.target->name);
 495                 return ret;
 496         }
 497         return 0;
 498 }
 499
 500 static inline int
 501 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 502                  unsigned int *i)
 503 {
 504         struct arpt_entry_target *t;
 505         struct xt_target *target;
 506         int ret;
 507
 508         ret = check_entry(e, name);
 509         if (ret)
 510                 return ret;
 511
 512         t = arpt_get_target(e);
 513         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 514                                                         t->u.user.name,
 515                                                         t->u.user.revision),
 516                                          "arpt_%s", t->u.user.name);
 517         if (IS_ERR(target) || !target) {
 518                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 519                 ret = target ? PTR_ERR(target) : -ENOENT;
 520                 goto out;
 521         }
 522         t->u.kernel.target = target;
 523
 524         ret = check_target(e, name);
 525         if (ret)
 526                 goto err;
 527
 528         (*i)++;
 529         return 0;
 530 err:
 531         module_put(t->u.kernel.target->me);
 532 out:
 533         return ret;
 534 }
 535
 536 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 537                                              struct xt_table_info *newinfo,
 538                                              unsigned char *base,
 539                                              unsigned char *limit,
 540                                              const unsigned int *hook_entries,
 541                                              const unsigned int *underflows,
 542                                              unsigned int valid_hooks,
 543                                              unsigned int *i)
 544 {
 545         unsigned int h;
 546
 547         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 548             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 549                 duprintf("Bad offset %p\n", e);
 550                 return -EINVAL;
 551         }
 552
 553         if (e->next_offset
 554             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 555                 duprintf("checking: element %p size %u\n",
 556                          e, e->next_offset);
 557                 return -EINVAL;
 558         }
 559
 560         /* Check hooks & underflows */
 561         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 562                 if (!(valid_hooks & (1 << h)))
 563                         continue;
 564                 if ((unsigned char *)e - base == hook_entries[h])
 565                         newinfo->hook_entry[h] = hook_entries[h];
 566                 if ((unsigned char *)e - base == underflows[h]) {
 567                         if (!unconditional(&e->arp)) {
 568                                 pr_err("Underflows must be unconditional\n");
 569                                 return -EINVAL;
 570                         }
 571                         newinfo->underflow[h] = underflows[h];
 572                 }
 573         }
 574
 575         /* Clear counters and comefrom */
 576         e->counters = ((struct xt_counters) { 0, 0 });
 577         e->comefrom = 0;
 578
 579         (*i)++;
 580         return 0;
 581 }
 582
 583 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 584 {
 585         struct xt_tgdtor_param par;
 586         struct arpt_entry_target *t;
 587
 588         if (i && (*i)-- == 0)
 589                 return 1;
 590
 591         t = arpt_get_target(e);
 592         par.target   = t->u.kernel.target;
 593         par.targinfo = t->data;
 594         par.family   = NFPROTO_ARP;
 595         if (par.target->destroy != NULL)
 596                 par.target->destroy(&par);
 597         module_put(par.target->me);
 598         return 0;
 599 }
 600
 601 /* Checks and translates the user-supplied table segment (held in
 602  * newinfo).
 603  */
 604 static int translate_table(const char *name,
 605                            unsigned int valid_hooks,
 606                            struct xt_table_info *newinfo,
 607                            void *entry0,
 608                            unsigned int size,
 609                            unsigned int number,
 610                            const unsigned int *hook_entries,
 611                            const unsigned int *underflows)
 612 {
 613         unsigned int i;
 614         int ret;
 615
 616         newinfo->size = size;
 617         newinfo->number = number;
 618
 619         /* Init all hooks to impossible value. */
 620         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 621                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 622                 newinfo->underflow[i] = 0xFFFFFFFF;
 623         }
 624
 625         duprintf("translate_table: size %u\n", newinfo->size);
 626         i = 0;
 627
 628         /* Walk through entries, checking offsets. */
 629         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 630                                  check_entry_size_and_hooks,
 631                                  newinfo,
 632                                  entry0,
 633                                  entry0 + size,
 634                                  hook_entries, underflows, valid_hooks, &i);
 635         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 636         if (ret != 0)
 637                 return ret;
 638
 639         if (i != number) {
 640                 duprintf("translate_table: %u not %u entries\n",
 641                          i, number);
 642                 return -EINVAL;
 643         }
 644
 645         /* Check hooks all assigned */
 646         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 647                 /* Only hooks which are valid */
 648                 if (!(valid_hooks & (1 << i)))
 649                         continue;
 650                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 651                         duprintf("Invalid hook entry %u %u\n",
 652                                  i, hook_entries[i]);
 653                         return -EINVAL;
 654                 }
 655                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 656                         duprintf("Invalid underflow %u %u\n",
 657                                  i, underflows[i]);
 658                         return -EINVAL;
 659                 }
 660         }
 661
 662         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 663                 duprintf("Looping hook\n");
 664                 return -ELOOP;
 665         }
 666
 667         /* Finally, each sanity check must pass */
 668         i = 0;
 669         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 670                                  find_check_entry, name, size, &i);
 671
 672         if (ret != 0) {
 673                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 674                                 cleanup_entry, &i);
 675                 return ret;
 676         }
 677
 678         /* And one copy for every other CPU */
 679         for_each_possible_cpu(i) {
 680                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 681                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 682         }
 683
 684         return ret;
 685 }
 686
 687 /* Gets counters. */
 688 static inline int add_entry_to_counter(const struct arpt_entry *e,
 689                                        struct xt_counters total[],
 690                                        unsigned int *i)
 691 {
 692         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 693
 694         (*i)++;
 695         return 0;
 696 }
 697
 698 static inline int set_entry_to_counter(const struct arpt_entry *e,
 699                                        struct xt_counters total[],
 700                                        unsigned int *i)
 701 {
 702         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 703
 704         (*i)++;
 705         return 0;
 706 }
 707
 708 static void get_counters(const struct xt_table_info *t,
 709                          struct xt_counters counters[])
 710 {
 711         unsigned int cpu;
 712         unsigned int i;
 713         unsigned int curcpu;
 714
 715         /* Instead of clearing (by a previous call to memset())
 716          * the counters and using adds, we set the counters
 717          * with data used by 'current' CPU
 718          *
 719          * Bottom half has to be disabled to prevent deadlock
 720          * if new softirq were to run and call ipt_do_table
 721          */
 722         local_bh_disable();
 723         curcpu = smp_processor_id();
 724
 725         i = 0;
 726         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 727                            t->size,
 728                            set_entry_to_counter,
 729                            counters,
 730                            &i);
 731
 732         for_each_possible_cpu(cpu) {
 733                 if (cpu == curcpu)
 734                         continue;
 735                 i = 0;
 736                 xt_info_wrlock(cpu);
 737                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 738                                    t->size,
 739                                    add_entry_to_counter,
 740                                    counters,
 741                                    &i);
 742                 xt_info_wrunlock(cpu);
 743         }
 744         local_bh_enable();
 745 }
 746
 747 static struct xt_counters *alloc_counters(struct xt_table *table)
 748 {
 749         unsigned int countersize;
 750         struct xt_counters *counters;
 751         struct xt_table_info *private = table->private;
 752
 753         /* We need atomic snapshot of counters: rest doesn't change
 754          * (other than comefrom, which userspace doesn't care
 755          * about).
 756          */
 757         countersize = sizeof(struct xt_counters) * private->number;
 758         counters = vmalloc_node(countersize, numa_node_id());
 759
 760         if (counters == NULL)
 761                 return ERR_PTR(-ENOMEM);
 762
 763         get_counters(private, counters);
 764
 765         return counters;
 766 }
 767
 768 static int copy_entries_to_user(unsigned int total_size,
 769                                 struct xt_table *table,
 770                                 void __user *userptr)
 771 {
 772         unsigned int off, num;
 773         struct arpt_entry *e;
 774         struct xt_counters *counters;
 775         struct xt_table_info *private = table->private;
 776         int ret = 0;
 777         void *loc_cpu_entry;
 778
 779         counters = alloc_counters(table);
 780         if (IS_ERR(counters))
 781                 return PTR_ERR(counters);
 782
 783         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 784         /* ... then copy entire thing ... */
 785         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 786                 ret = -EFAULT;
 787                 goto free_counters;
 788         }
 789
 790         /* FIXME: use iterator macros --RR */
 791         /* ... then go back and fix counters and names */
 792         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 793                 struct arpt_entry_target *t;
 794
 795                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 796                 if (copy_to_user(userptr + off
 797                                  + offsetof(struct arpt_entry, counters),
 798                                  &counters[num],
 799                                  sizeof(counters[num])) != 0) {
 800                         ret = -EFAULT;
 801                         goto free_counters;
 802                 }
 803
 804                 t = arpt_get_target(e);
 805                 if (copy_to_user(userptr + off + e->target_offset
 806                                  + offsetof(struct arpt_entry_target,
 807                                             u.user.name),
 808                                  t->u.kernel.target->name,
 809                                  strlen(t->u.kernel.target->name)+1) != 0) {
 810                         ret = -EFAULT;
 811                         goto free_counters;
 812                 }
 813         }
 814
 815  free_counters:
 816         vfree(counters);
 817         return ret;
 818 }
 819
 820 #ifdef CONFIG_COMPAT
 821 static void compat_standard_from_user(void *dst, void *src)
 822 {
 823         int v = *(compat_int_t *)src;
 824
 825         if (v > 0)
 826                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 827         memcpy(dst, &v, sizeof(v));
 828 }
 829
 830 static int compat_standard_to_user(void __user *dst, void *src)
 831 {
 832         compat_int_t cv = *(int *)src;
 833
 834         if (cv > 0)
 835                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 836         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 837 }
 838
 839 static int compat_calc_entry(struct arpt_entry *e,
 840                              const struct xt_table_info *info,
 841                              void *base, struct xt_table_info *newinfo)
 842 {
 843         struct arpt_entry_target *t;
 844         unsigned int entry_offset;
 845         int off, i, ret;
 846
 847         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 848         entry_offset = (void *)e - base;
 849
 850         t = arpt_get_target(e);
 851         off += xt_compat_target_offset(t->u.kernel.target);
 852         newinfo->size -= off;
 853         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 854         if (ret)
 855                 return ret;
 856
 857         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 858                 if (info->hook_entry[i] &&
 859                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 860                         newinfo->hook_entry[i] -= off;
 861                 if (info->underflow[i] &&
 862                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 863                         newinfo->underflow[i] -= off;
 864         }
 865         return 0;
 866 }
 867
 868 static int compat_table_info(const struct xt_table_info *info,
 869                              struct xt_table_info *newinfo)
 870 {
 871         void *loc_cpu_entry;
 872
 873         if (!newinfo || !info)
 874                 return -EINVAL;
 875
 876         /* we dont care about newinfo->entries[] */
 877         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 878         newinfo->initial_entries = 0;
 879         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 880         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 881                                   compat_calc_entry, info, loc_cpu_entry,
 882                                   newinfo);
 883 }
 884 #endif
 885
 886 static int get_info(struct net *net, void __user *user, int *len, int compat)
 887 {
 888         char name[ARPT_TABLE_MAXNAMELEN];
 889         struct xt_table *t;
 890         int ret;
 891
 892         if (*len != sizeof(struct arpt_getinfo)) {
 893                 duprintf("length %u != %Zu\n", *len,
 894                          sizeof(struct arpt_getinfo));
 895                 return -EINVAL;
 896         }
 897
 898         if (copy_from_user(name, user, sizeof(name)) != 0)
 899                 return -EFAULT;
 900
 901         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 902 #ifdef CONFIG_COMPAT
 903         if (compat)
 904                 xt_compat_lock(NFPROTO_ARP);
 905 #endif
 906         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 907                                     "arptable_%s", name);
 908         if (t && !IS_ERR(t)) {
 909                 struct arpt_getinfo info;
 910                 const struct xt_table_info *private = t->private;
 911
 912 #ifdef CONFIG_COMPAT
 913                 if (compat) {
 914                         struct xt_table_info tmp;
 915                         ret = compat_table_info(private, &tmp);
 916                         xt_compat_flush_offsets(NFPROTO_ARP);
 917                         private = &tmp;
 918                 }
 919 #endif
 920                 info.valid_hooks = t->valid_hooks;
 921                 memcpy(info.hook_entry, private->hook_entry,
 922                        sizeof(info.hook_entry));
 923                 memcpy(info.underflow, private->underflow,
 924                        sizeof(info.underflow));
 925                 info.num_entries = private->number;
 926                 info.size = private->size;
 927                 strcpy(info.name, name);
 928
 929                 if (copy_to_user(user, &info, *len) != 0)
 930                         ret = -EFAULT;
 931                 else
 932                         ret = 0;
 933                 xt_table_unlock(t);
 934                 module_put(t->me);
 935         } else
 936                 ret = t ? PTR_ERR(t) : -ENOENT;
 937 #ifdef CONFIG_COMPAT
 938         if (compat)
 939                 xt_compat_unlock(NFPROTO_ARP);
 940 #endif
 941         return ret;
 942 }
 943
 944 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 945                        int *len)
 946 {
 947         int ret;
 948         struct arpt_get_entries get;
 949         struct xt_table *t;
 950
 951         if (*len < sizeof(get)) {
 952                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 953                 return -EINVAL;
 954         }
 955         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 956                 return -EFAULT;
 957         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 958                 duprintf("get_entries: %u != %Zu\n", *len,
 959                          sizeof(struct arpt_get_entries) + get.size);
 960                 return -EINVAL;
 961         }
 962
 963         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 964         if (t && !IS_ERR(t)) {
 965                 const struct xt_table_info *private = t->private;
 966
 967                 duprintf("t->private->number = %u\n",
 968                          private->number);
 969                 if (get.size == private->size)
 970                         ret = copy_entries_to_user(private->size,
 971                                                    t, uptr->entrytable);
 972                 else {
 973                         duprintf("get_entries: I've got %u not %u!\n",
 974                                  private->size, get.size);
 975                         ret = -EAGAIN;
 976                 }
 977                 module_put(t->me);
 978                 xt_table_unlock(t);
 979         } else
 980                 ret = t ? PTR_ERR(t) : -ENOENT;
 981
 982         return ret;
 983 }
 984
 985 static int __do_replace(struct net *net, const char *name,
 986                         unsigned int valid_hooks,
 987                         struct xt_table_info *newinfo,
 988                         unsigned int num_counters,
 989                         void __user *counters_ptr)
 990 {
 991         int ret;
 992         struct xt_table *t;
 993         struct xt_table_info *oldinfo;
 994         struct xt_counters *counters;
 995         void *loc_cpu_old_entry;
 996
 997         ret = 0;
 998         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
 999                                 numa_node_id());
1000         if (!counters) {
1001                 ret = -ENOMEM;
1002                 goto out;
1003         }
1004
1005         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1006                                     "arptable_%s", name);
1007         if (!t || IS_ERR(t)) {
1008                 ret = t ? PTR_ERR(t) : -ENOENT;
1009                 goto free_newinfo_counters_untrans;
1010         }
1011
1012         /* You lied! */
1013         if (valid_hooks != t->valid_hooks) {
1014                 duprintf("Valid hook crap: %08X vs %08X\n",
1015                          valid_hooks, t->valid_hooks);
1016                 ret = -EINVAL;
1017                 goto put_module;
1018         }
1019
1020         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1021         if (!oldinfo)
1022                 goto put_module;
1023
1024         /* Update module usage count based on number of rules */
1025         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1026                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1027         if ((oldinfo->number > oldinfo->initial_entries) ||
1028             (newinfo->number <= oldinfo->initial_entries))
1029                 module_put(t->me);
1030         if ((oldinfo->number > oldinfo->initial_entries) &&
1031             (newinfo->number <= oldinfo->initial_entries))
1032                 module_put(t->me);
1033
1034         /* Get the old counters, and synchronize with replace */
1035         get_counters(oldinfo, counters);
1036
1037         /* Decrease module usage counts and free resource */
1038         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1039         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1040                            NULL);
1041
1042         xt_free_table_info(oldinfo);
1043         if (copy_to_user(counters_ptr, counters,
1044                          sizeof(struct xt_counters) * num_counters) != 0)
1045                 ret = -EFAULT;
1046         vfree(counters);
1047         xt_table_unlock(t);
1048         return ret;
1049
1050  put_module:
1051         module_put(t->me);
1052         xt_table_unlock(t);
1053  free_newinfo_counters_untrans:
1054         vfree(counters);
1055  out:
1056         return ret;
1057 }
1058
1059 static int do_replace(struct net *net, void __user *user, unsigned int len)
1060 {
1061         int ret;
1062         struct arpt_replace tmp;
1063         struct xt_table_info *newinfo;
1064         void *loc_cpu_entry;
1065
1066         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1067                 return -EFAULT;
1068
1069         /* overflow check */
1070         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1071                 return -ENOMEM;
1072
1073         newinfo = xt_alloc_table_info(tmp.size);
1074         if (!newinfo)
1075                 return -ENOMEM;
1076
1077         /* choose the copy that is on our node/cpu */
1078         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1079         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1080                            tmp.size) != 0) {
1081                 ret = -EFAULT;
1082                 goto free_newinfo;
1083         }
1084
1085         ret = translate_table(tmp.name, tmp.valid_hooks,
1086                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1087                               tmp.hook_entry, tmp.underflow);
1088         if (ret != 0)
1089                 goto free_newinfo;
1090
1091         duprintf("arp_tables: Translated table\n");
1092
1093         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1094                            tmp.num_counters, tmp.counters);
1095         if (ret)
1096                 goto free_newinfo_untrans;
1097         return 0;
1098
1099  free_newinfo_untrans:
1100         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1101  free_newinfo:
1102         xt_free_table_info(newinfo);
1103         return ret;
1104 }
1105
1106 /* We're lazy, and add to the first CPU; overflow works its fey magic
1107  * and everything is OK. */
1108 static int
1109 add_counter_to_entry(struct arpt_entry *e,
1110                      const struct xt_counters addme[],
1111                      unsigned int *i)
1112 {
1113         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1114
1115         (*i)++;
1116         return 0;
1117 }
1118
1119 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1120                            int compat)
1121 {
1122         unsigned int i, curcpu;
1123         struct xt_counters_info tmp;
1124         struct xt_counters *paddc;
1125         unsigned int num_counters;
1126         const char *name;
1127         int size;
1128         void *ptmp;
1129         struct xt_table *t;
1130         const struct xt_table_info *private;
1131         int ret = 0;
1132         void *loc_cpu_entry;
1133 #ifdef CONFIG_COMPAT
1134         struct compat_xt_counters_info compat_tmp;
1135
1136         if (compat) {
1137                 ptmp = &compat_tmp;
1138                 size = sizeof(struct compat_xt_counters_info);
1139         } else
1140 #endif
1141         {
1142                 ptmp = &tmp;
1143                 size = sizeof(struct xt_counters_info);
1144         }
1145
1146         if (copy_from_user(ptmp, user, size) != 0)
1147                 return -EFAULT;
1148
1149 #ifdef CONFIG_COMPAT
1150         if (compat) {
1151                 num_counters = compat_tmp.num_counters;
1152                 name = compat_tmp.name;
1153         } else
1154 #endif
1155         {
1156                 num_counters = tmp.num_counters;
1157                 name = tmp.name;
1158         }
1159
1160         if (len != size + num_counters * sizeof(struct xt_counters))
1161                 return -EINVAL;
1162
1163         paddc = vmalloc_node(len - size, numa_node_id());
1164         if (!paddc)
1165                 return -ENOMEM;
1166
1167         if (copy_from_user(paddc, user + size, len - size) != 0) {
1168                 ret = -EFAULT;
1169                 goto free;
1170         }
1171
1172         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1173         if (!t || IS_ERR(t)) {
1174                 ret = t ? PTR_ERR(t) : -ENOENT;
1175                 goto free;
1176         }
1177
1178         local_bh_disable();
1179         private = t->private;
1180         if (private->number != num_counters) {
1181                 ret = -EINVAL;
1182                 goto unlock_up_free;
1183         }
1184
1185         i = 0;
1186         /* Choose the copy that is on our node */
1187         curcpu = smp_processor_id();
1188         loc_cpu_entry = private->entries[curcpu];
1189         xt_info_wrlock(curcpu);
1190         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1191                            private->size,
1192                            add_counter_to_entry,
1193                            paddc,
1194                            &i);
1195         xt_info_wrunlock(curcpu);
1196  unlock_up_free:
1197         local_bh_enable();
1198         xt_table_unlock(t);
1199         module_put(t->me);
1200  free:
1201         vfree(paddc);
1202
1203         return ret;
1204 }
1205
1206 #ifdef CONFIG_COMPAT
1207 static inline int
1208 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1209 {
1210         struct arpt_entry_target *t;
1211
1212         if (i && (*i)-- == 0)
1213                 return 1;
1214
1215         t = compat_arpt_get_target(e);
1216         module_put(t->u.kernel.target->me);
1217         return 0;
1218 }
1219
1220 static inline int
1221 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1222                                   struct xt_table_info *newinfo,
1223                                   unsigned int *size,
1224                                   unsigned char *base,
1225                                   unsigned char *limit,
1226                                   unsigned int *hook_entries,
1227                                   unsigned int *underflows,
1228                                   unsigned int *i,
1229                                   const char *name)
1230 {
1231         struct arpt_entry_target *t;
1232         struct xt_target *target;
1233         unsigned int entry_offset;
1234         int ret, off, h;
1235
1236         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1237         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1238             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1239                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1240                 return -EINVAL;
1241         }
1242
1243         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1244                              sizeof(struct compat_xt_entry_target)) {
1245                 duprintf("checking: element %p size %u\n",
1246                          e, e->next_offset);
1247                 return -EINVAL;
1248         }
1249
1250         /* For purposes of check_entry casting the compat entry is fine */
1251         ret = check_entry((struct arpt_entry *)e, name);
1252         if (ret)
1253                 return ret;
1254
1255         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1256         entry_offset = (void *)e - (void *)base;
1257
1258         t = compat_arpt_get_target(e);
1259         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1260                                                         t->u.user.name,
1261                                                         t->u.user.revision),
1262                                          "arpt_%s", t->u.user.name);
1263         if (IS_ERR(target) || !target) {
1264                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1265                          t->u.user.name);
1266                 ret = target ? PTR_ERR(target) : -ENOENT;
1267                 goto out;
1268         }
1269         t->u.kernel.target = target;
1270
1271         off += xt_compat_target_offset(target);
1272         *size += off;
1273         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1274         if (ret)
1275                 goto release_target;
1276
1277         /* Check hooks & underflows */
1278         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1279                 if ((unsigned char *)e - base == hook_entries[h])
1280                         newinfo->hook_entry[h] = hook_entries[h];
1281                 if ((unsigned char *)e - base == underflows[h])
1282                         newinfo->underflow[h] = underflows[h];
1283         }
1284
1285         /* Clear counters and comefrom */
1286         memset(&e->counters, 0, sizeof(e->counters));
1287         e->comefrom = 0;
1288
1289         (*i)++;
1290         return 0;
1291
1292 release_target:
1293         module_put(t->u.kernel.target->me);
1294 out:
1295         return ret;
1296 }
1297
1298 static int
1299 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1300                             unsigned int *size, const char *name,
1301                             struct xt_table_info *newinfo, unsigned char *base)
1302 {
1303         struct arpt_entry_target *t;
1304         struct xt_target *target;
1305         struct arpt_entry *de;
1306         unsigned int origsize;
1307         int ret, h;
1308
1309         ret = 0;
1310         origsize = *size;
1311         de = (struct arpt_entry *)*dstptr;
1312         memcpy(de, e, sizeof(struct arpt_entry));
1313         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1314
1315         *dstptr += sizeof(struct arpt_entry);
1316         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1317
1318         de->target_offset = e->target_offset - (origsize - *size);
1319         t = compat_arpt_get_target(e);
1320         target = t->u.kernel.target;
1321         xt_compat_target_from_user(t, dstptr, size);
1322
1323         de->next_offset = e->next_offset - (origsize - *size);
1324         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1325                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1326                         newinfo->hook_entry[h] -= origsize - *size;
1327                 if ((unsigned char *)de - base < newinfo->underflow[h])
1328                         newinfo->underflow[h] -= origsize - *size;
1329         }
1330         return ret;
1331 }
1332
1333 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1334                                      unsigned int *i)
1335 {
1336         int ret;
1337
1338         ret = check_target(e, name);
1339         if (ret)
1340                 return ret;
1341
1342         (*i)++;
1343         return 0;
1344 }
1345
1346 static int translate_compat_table(const char *name,
1347                                   unsigned int valid_hooks,
1348                                   struct xt_table_info **pinfo,
1349                                   void **pentry0,
1350                                   unsigned int total_size,
1351                                   unsigned int number,
1352                                   unsigned int *hook_entries,
1353                                   unsigned int *underflows)
1354 {
1355         unsigned int i, j;
1356         struct xt_table_info *newinfo, *info;
1357         void *pos, *entry0, *entry1;
1358         unsigned int size;
1359         int ret;
1360
1361         info = *pinfo;
1362         entry0 = *pentry0;
1363         size = total_size;
1364         info->number = number;
1365
1366         /* Init all hooks to impossible value. */
1367         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1368                 info->hook_entry[i] = 0xFFFFFFFF;
1369                 info->underflow[i] = 0xFFFFFFFF;
1370         }
1371
1372         duprintf("translate_compat_table: size %u\n", info->size);
1373         j = 0;
1374         xt_compat_lock(NFPROTO_ARP);
1375         /* Walk through entries, checking offsets. */
1376         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1377                                         check_compat_entry_size_and_hooks,
1378                                         info, &size, entry0,
1379                                         entry0 + total_size,
1380                                         hook_entries, underflows, &j, name);
1381         if (ret != 0)
1382                 goto out_unlock;
1383
1384         ret = -EINVAL;
1385         if (j != number) {
1386                 duprintf("translate_compat_table: %u not %u entries\n",
1387                          j, number);
1388                 goto out_unlock;
1389         }
1390
1391         /* Check hooks all assigned */
1392         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1393                 /* Only hooks which are valid */
1394                 if (!(valid_hooks & (1 << i)))
1395                         continue;
1396                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1397                         duprintf("Invalid hook entry %u %u\n",
1398                                  i, hook_entries[i]);
1399                         goto out_unlock;
1400                 }
1401                 if (info->underflow[i] == 0xFFFFFFFF) {
1402                         duprintf("Invalid underflow %u %u\n",
1403                                  i, underflows[i]);
1404                         goto out_unlock;
1405                 }
1406         }
1407
1408         ret = -ENOMEM;
1409         newinfo = xt_alloc_table_info(size);
1410         if (!newinfo)
1411                 goto out_unlock;
1412
1413         newinfo->number = number;
1414         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1415                 newinfo->hook_entry[i] = info->hook_entry[i];
1416                 newinfo->underflow[i] = info->underflow[i];
1417         }
1418         entry1 = newinfo->entries[raw_smp_processor_id()];
1419         pos = entry1;
1420         size = total_size;
1421         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1422                                         compat_copy_entry_from_user,
1423                                         &pos, &size, name, newinfo, entry1);
1424         xt_compat_flush_offsets(NFPROTO_ARP);
1425         xt_compat_unlock(NFPROTO_ARP);
1426         if (ret)
1427                 goto free_newinfo;
1428
1429         ret = -ELOOP;
1430         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1431                 goto free_newinfo;
1432
1433         i = 0;
1434         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1435                                  name, &i);
1436         if (ret) {
1437                 j -= i;
1438                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1439                                                    compat_release_entry, &j);
1440                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1441                 xt_free_table_info(newinfo);
1442                 return ret;
1443         }
1444
1445         /* And one copy for every other CPU */
1446         for_each_possible_cpu(i)
1447                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1448                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1449
1450         *pinfo = newinfo;
1451         *pentry0 = entry1;
1452         xt_free_table_info(info);
1453         return 0;
1454
1455 free_newinfo:
1456         xt_free_table_info(newinfo);
1457 out:
1458         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1459         return ret;
1460 out_unlock:
1461         xt_compat_flush_offsets(NFPROTO_ARP);
1462         xt_compat_unlock(NFPROTO_ARP);
1463         goto out;
1464 }
1465
1466 struct compat_arpt_replace {
1467         char                            name[ARPT_TABLE_MAXNAMELEN];
1468         u32                             valid_hooks;
1469         u32                             num_entries;
1470         u32                             size;
1471         u32                             hook_entry[NF_ARP_NUMHOOKS];
1472         u32                             underflow[NF_ARP_NUMHOOKS];
1473         u32                             num_counters;
1474         compat_uptr_t                   counters;
1475         struct compat_arpt_entry        entries[0];
1476 };
1477
1478 static int compat_do_replace(struct net *net, void __user *user,
1479                              unsigned int len)
1480 {
1481         int ret;
1482         struct compat_arpt_replace tmp;
1483         struct xt_table_info *newinfo;
1484         void *loc_cpu_entry;
1485
1486         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1487                 return -EFAULT;
1488
1489         /* overflow check */
1490         if (tmp.size >= INT_MAX / num_possible_cpus())
1491                 return -ENOMEM;
1492         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1493                 return -ENOMEM;
1494
1495         newinfo = xt_alloc_table_info(tmp.size);
1496         if (!newinfo)
1497                 return -ENOMEM;
1498
1499         /* choose the copy that is on our node/cpu */
1500         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1501         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1502                 ret = -EFAULT;
1503                 goto free_newinfo;
1504         }
1505
1506         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1507                                      &newinfo, &loc_cpu_entry, tmp.size,
1508                                      tmp.num_entries, tmp.hook_entry,
1509                                      tmp.underflow);
1510         if (ret != 0)
1511                 goto free_newinfo;
1512
1513         duprintf("compat_do_replace: Translated table\n");
1514
1515         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1516                            tmp.num_counters, compat_ptr(tmp.counters));
1517         if (ret)
1518                 goto free_newinfo_untrans;
1519         return 0;
1520
1521  free_newinfo_untrans:
1522         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1523  free_newinfo:
1524         xt_free_table_info(newinfo);
1525         return ret;
1526 }
1527
1528 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1529                                   unsigned int len)
1530 {
1531         int ret;
1532
1533         if (!capable(CAP_NET_ADMIN))
1534                 return -EPERM;
1535
1536         switch (cmd) {
1537         case ARPT_SO_SET_REPLACE:
1538                 ret = compat_do_replace(sock_net(sk), user, len);
1539                 break;
1540
1541         case ARPT_SO_SET_ADD_COUNTERS:
1542                 ret = do_add_counters(sock_net(sk), user, len, 1);
1543                 break;
1544
1545         default:
1546                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1547                 ret = -EINVAL;
1548         }
1549
1550         return ret;
1551 }
1552
1553 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1554                                      compat_uint_t *size,
1555                                      struct xt_counters *counters,
1556                                      unsigned int *i)
1557 {
1558         struct arpt_entry_target *t;
1559         struct compat_arpt_entry __user *ce;
1560         u_int16_t target_offset, next_offset;
1561         compat_uint_t origsize;
1562         int ret;
1563
1564         ret = -EFAULT;
1565         origsize = *size;
1566         ce = (struct compat_arpt_entry __user *)*dstptr;
1567         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1568                 goto out;
1569
1570         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1571                 goto out;
1572
1573         *dstptr += sizeof(struct compat_arpt_entry);
1574         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1575
1576         target_offset = e->target_offset - (origsize - *size);
1577
1578         t = arpt_get_target(e);
1579         ret = xt_compat_target_to_user(t, dstptr, size);
1580         if (ret)
1581                 goto out;
1582         ret = -EFAULT;
1583         next_offset = e->next_offset - (origsize - *size);
1584         if (put_user(target_offset, &ce->target_offset))
1585                 goto out;
1586         if (put_user(next_offset, &ce->next_offset))
1587                 goto out;
1588
1589         (*i)++;
1590         return 0;
1591 out:
1592         return ret;
1593 }
1594
1595 static int compat_copy_entries_to_user(unsigned int total_size,
1596                                        struct xt_table *table,
1597                                        void __user *userptr)
1598 {
1599         struct xt_counters *counters;
1600         const struct xt_table_info *private = table->private;
1601         void __user *pos;
1602         unsigned int size;
1603         int ret = 0;
1604         void *loc_cpu_entry;
1605         unsigned int i = 0;
1606
1607         counters = alloc_counters(table);
1608         if (IS_ERR(counters))
1609                 return PTR_ERR(counters);
1610
1611         /* choose the copy on our node/cpu */
1612         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1613         pos = userptr;
1614         size = total_size;
1615         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1616                                  compat_copy_entry_to_user,
1617                                  &pos, &size, counters, &i);
1618         vfree(counters);
1619         return ret;
1620 }
1621
1622 struct compat_arpt_get_entries {
1623         char name[ARPT_TABLE_MAXNAMELEN];
1624         compat_uint_t size;
1625         struct compat_arpt_entry entrytable[0];
1626 };
1627
1628 static int compat_get_entries(struct net *net,
1629                               struct compat_arpt_get_entries __user *uptr,
1630                               int *len)
1631 {
1632         int ret;
1633         struct compat_arpt_get_entries get;
1634         struct xt_table *t;
1635
1636         if (*len < sizeof(get)) {
1637                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1638                 return -EINVAL;
1639         }
1640         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1641                 return -EFAULT;
1642         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1643                 duprintf("compat_get_entries: %u != %zu\n",
1644                          *len, sizeof(get) + get.size);
1645                 return -EINVAL;
1646         }
1647
1648         xt_compat_lock(NFPROTO_ARP);
1649         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1650         if (t && !IS_ERR(t)) {
1651                 const struct xt_table_info *private = t->private;
1652                 struct xt_table_info info;
1653
1654                 duprintf("t->private->number = %u\n", private->number);
1655                 ret = compat_table_info(private, &info);
1656                 if (!ret && get.size == info.size) {
1657                         ret = compat_copy_entries_to_user(private->size,
1658                                                           t, uptr->entrytable);
1659                 } else if (!ret) {
1660                         duprintf("compat_get_entries: I've got %u not %u!\n",
1661                                  private->size, get.size);
1662                         ret = -EAGAIN;
1663                 }
1664                 xt_compat_flush_offsets(NFPROTO_ARP);
1665                 module_put(t->me);
1666                 xt_table_unlock(t);
1667         } else
1668                 ret = t ? PTR_ERR(t) : -ENOENT;
1669
1670         xt_compat_unlock(NFPROTO_ARP);
1671         return ret;
1672 }
1673
1674 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1675
1676 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1677                                   int *len)
1678 {
1679         int ret;
1680
1681         if (!capable(CAP_NET_ADMIN))
1682                 return -EPERM;
1683
1684         switch (cmd) {
1685         case ARPT_SO_GET_INFO:
1686                 ret = get_info(sock_net(sk), user, len, 1);
1687                 break;
1688         case ARPT_SO_GET_ENTRIES:
1689                 ret = compat_get_entries(sock_net(sk), user, len);
1690                 break;
1691         default:
1692                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1693         }
1694         return ret;
1695 }
1696 #endif
1697
1698 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1699 {
1700         int ret;
1701
1702         if (!capable(CAP_NET_ADMIN))
1703                 return -EPERM;
1704
1705         switch (cmd) {
1706         case ARPT_SO_SET_REPLACE:
1707                 ret = do_replace(sock_net(sk), user, len);
1708                 break;
1709
1710         case ARPT_SO_SET_ADD_COUNTERS:
1711                 ret = do_add_counters(sock_net(sk), user, len, 0);
1712                 break;
1713
1714         default:
1715                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1716                 ret = -EINVAL;
1717         }
1718
1719         return ret;
1720 }
1721
1722 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1723 {
1724         int ret;
1725
1726         if (!capable(CAP_NET_ADMIN))
1727                 return -EPERM;
1728
1729         switch (cmd) {
1730         case ARPT_SO_GET_INFO:
1731                 ret = get_info(sock_net(sk), user, len, 0);
1732                 break;
1733
1734         case ARPT_SO_GET_ENTRIES:
1735                 ret = get_entries(sock_net(sk), user, len);
1736                 break;
1737
1738         case ARPT_SO_GET_REVISION_TARGET: {
1739                 struct xt_get_revision rev;
1740
1741                 if (*len != sizeof(rev)) {
1742                         ret = -EINVAL;
1743                         break;
1744                 }
1745                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1746                         ret = -EFAULT;
1747                         break;
1748                 }
1749
1750                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1751                                                          rev.revision, 1, &ret),
1752                                         "arpt_%s", rev.name);
1753                 break;
1754         }
1755
1756         default:
1757                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1758                 ret = -EINVAL;
1759         }
1760
1761         return ret;
1762 }
1763
1764 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1765                                      const struct arpt_replace *repl)
1766 {
1767         int ret;
1768         struct xt_table_info *newinfo;
1769         struct xt_table_info bootstrap
1770                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1771         void *loc_cpu_entry;
1772         struct xt_table *new_table;
1773
1774         newinfo = xt_alloc_table_info(repl->size);
1775         if (!newinfo) {
1776                 ret = -ENOMEM;
1777                 goto out;
1778         }
1779
1780         /* choose the copy on our node/cpu */
1781         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1782         memcpy(loc_cpu_entry, repl->entries, repl->size);
1783
1784         ret = translate_table(table->name, table->valid_hooks,
1785                               newinfo, loc_cpu_entry, repl->size,
1786                               repl->num_entries,
1787                               repl->hook_entry,
1788                               repl->underflow);
1789
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
1813         private = xt_unregister_table(table);
1814
1815         /* Decrease module usage counts and free resources */
1816         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1817         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1818                            cleanup_entry, NULL);
1819         if (private->number > private->initial_entries)
1820                 module_put(table_owner);
1821         xt_free_table_info(private);
1822 }
1823
1824 /* The built-in targets: standard (NULL) and error. */
1825 static struct xt_target arpt_standard_target __read_mostly = {
1826         .name           = ARPT_STANDARD_TARGET,
1827         .targetsize     = sizeof(int),
1828         .family         = NFPROTO_ARP,
1829 #ifdef CONFIG_COMPAT
1830         .compatsize     = sizeof(compat_int_t),
1831         .compat_from_user = compat_standard_from_user,
1832         .compat_to_user = compat_standard_to_user,
1833 #endif
1834 };
1835
1836 static struct xt_target arpt_error_target __read_mostly = {
1837         .name           = ARPT_ERROR_TARGET,
1838         .target         = arpt_error,
1839         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1840         .family         = NFPROTO_ARP,
1841 };
1842
1843 static struct nf_sockopt_ops arpt_sockopts = {
1844         .pf             = PF_INET,
1845         .set_optmin     = ARPT_BASE_CTL,
1846         .set_optmax     = ARPT_SO_SET_MAX+1,
1847         .set            = do_arpt_set_ctl,
1848 #ifdef CONFIG_COMPAT
1849         .compat_set     = compat_do_arpt_set_ctl,
1850 #endif
1851         .get_optmin     = ARPT_BASE_CTL,
1852         .get_optmax     = ARPT_SO_GET_MAX+1,
1853         .get            = do_arpt_get_ctl,
1854 #ifdef CONFIG_COMPAT
1855         .compat_get     = compat_do_arpt_get_ctl,
1856 #endif
1857         .owner          = THIS_MODULE,
1858 };
1859
1860 static int __net_init arp_tables_net_init(struct net *net)
1861 {
1862         return xt_proto_init(net, NFPROTO_ARP);
1863 }
1864
1865 static void __net_exit arp_tables_net_exit(struct net *net)
1866 {
1867         xt_proto_fini(net, NFPROTO_ARP);
1868 }
1869
1870 static struct pernet_operations arp_tables_net_ops = {
1871         .init = arp_tables_net_init,
1872         .exit = arp_tables_net_exit,
1873 };
1874
1875 static int __init arp_tables_init(void)
1876 {
1877         int ret;
1878
1879         ret = register_pernet_subsys(&arp_tables_net_ops);
1880         if (ret < 0)
1881                 goto err1;
1882
1883         /* Noone else will be downing sem now, so we won't sleep */
1884         ret = xt_register_target(&arpt_standard_target);
1885         if (ret < 0)
1886                 goto err2;
1887         ret = xt_register_target(&arpt_error_target);
1888         if (ret < 0)
1889                 goto err3;
1890
1891         /* Register setsockopt */
1892         ret = nf_register_sockopt(&arpt_sockopts);
1893         if (ret < 0)
1894                 goto err4;
1895
1896         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1897         return 0;
1898
1899 err4:
1900         xt_unregister_target(&arpt_error_target);
1901 err3:
1902         xt_unregister_target(&arpt_standard_target);
1903 err2:
1904         unregister_pernet_subsys(&arp_tables_net_ops);
1905 err1:
1906         return ret;
1907 }
1908
1909 static void __exit arp_tables_fini(void)
1910 {
1911         nf_unregister_sockopt(&arpt_sockopts);
1912         xt_unregister_target(&arpt_error_target);
1913         xt_unregister_target(&arpt_standard_target);
1914         unregister_pernet_subsys(&arp_tables_net_ops);
1915 }
1916
1917 EXPORT_SYMBOL(arpt_register_table);
1918 EXPORT_SYMBOL(arpt_unregister_table);
1919 EXPORT_SYMBOL(arpt_do_table);
1920
1921 module_init(arp_tables_init);
1922 module_exit(arp_tables_fini);