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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
  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  */
  80 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  81 {
  82 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  83         const unsigned long *a = (const unsigned long *)_a;
  84         const unsigned long *b = (const unsigned long *)_b;
  85         const unsigned long *mask = (const unsigned long *)_mask;
  86         unsigned long ret;
  87
  88         ret = (a[0] ^ b[0]) & mask[0];
  89         if (IFNAMSIZ > sizeof(unsigned long))
  90                 ret |= (a[1] ^ b[1]) & mask[1];
  91         if (IFNAMSIZ > 2 * sizeof(unsigned long))
  92                 ret |= (a[2] ^ b[2]) & mask[2];
  93         if (IFNAMSIZ > 3 * sizeof(unsigned long))
  94                 ret |= (a[3] ^ b[3]) & mask[3];
  95         BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
  96 #else
  97         unsigned long ret = 0;
  98         int i;
  99
 100         for (i = 0; i < IFNAMSIZ; i++)
 101                 ret |= (_a[i] ^ _b[i]) & _mask[i];
 102 #endif
 103         return ret;
 104 }
 105
 106 /* Returns whether packet matches rule or not. */
 107 static inline int arp_packet_match(const struct arphdr *arphdr,
 108                                    struct net_device *dev,
 109                                    const char *indev,
 110                                    const char *outdev,
 111                                    const struct arpt_arp *arpinfo)
 112 {
 113         const char *arpptr = (char *)(arphdr + 1);
 114         const char *src_devaddr, *tgt_devaddr;
 115         __be32 src_ipaddr, tgt_ipaddr;
 116         long ret;
 117
 118 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 119
 120         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 121                   ARPT_INV_ARPOP)) {
 122                 dprintf("ARP operation field mismatch.\n");
 123                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 124                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 125                 return 0;
 126         }
 127
 128         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 129                   ARPT_INV_ARPHRD)) {
 130                 dprintf("ARP hardware address format mismatch.\n");
 131                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 132                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 133                 return 0;
 134         }
 135
 136         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 137                   ARPT_INV_ARPPRO)) {
 138                 dprintf("ARP protocol address format mismatch.\n");
 139                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 140                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 141                 return 0;
 142         }
 143
 144         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 145                   ARPT_INV_ARPHLN)) {
 146                 dprintf("ARP hardware address length mismatch.\n");
 147                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 148                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 149                 return 0;
 150         }
 151
 152         src_devaddr = arpptr;
 153         arpptr += dev->addr_len;
 154         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 155         arpptr += sizeof(u32);
 156         tgt_devaddr = arpptr;
 157         arpptr += dev->addr_len;
 158         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 159
 160         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 161                   ARPT_INV_SRCDEVADDR) ||
 162             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 163                   ARPT_INV_TGTDEVADDR)) {
 164                 dprintf("Source or target device address mismatch.\n");
 165
 166                 return 0;
 167         }
 168
 169         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 170                   ARPT_INV_SRCIP) ||
 171             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 172                   ARPT_INV_TGTIP)) {
 173                 dprintf("Source or target IP address mismatch.\n");
 174
 175                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 176                         &src_ipaddr,
 177                         &arpinfo->smsk.s_addr,
 178                         &arpinfo->src.s_addr,
 179                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 180                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 181                         &tgt_ipaddr,
 182                         &arpinfo->tmsk.s_addr,
 183                         &arpinfo->tgt.s_addr,
 184                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 185                 return 0;
 186         }
 187
 188         /* Look for ifname matches.  */
 189         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 190
 191         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 192                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 193                         indev, arpinfo->iniface,
 194                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 195                 return 0;
 196         }
 197
 198         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 199
 200         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 201                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 202                         outdev, arpinfo->outiface,
 203                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 204                 return 0;
 205         }
 206
 207         return 1;
 208 #undef FWINV
 209 }
 210
 211 static inline int arp_checkentry(const struct arpt_arp *arp)
 212 {
 213         if (arp->flags & ~ARPT_F_MASK) {
 214                 duprintf("Unknown flag bits set: %08X\n",
 215                          arp->flags & ~ARPT_F_MASK);
 216                 return 0;
 217         }
 218         if (arp->invflags & ~ARPT_INV_MASK) {
 219                 duprintf("Unknown invflag bits set: %08X\n",
 220                          arp->invflags & ~ARPT_INV_MASK);
 221                 return 0;
 222         }
 223
 224         return 1;
 225 }
 226
 227 static unsigned int
 228 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 229 {
 230         if (net_ratelimit())
 231                 printk("arp_tables: error: '%s'\n",
 232                        (const char *)par->targinfo);
 233
 234         return NF_DROP;
 235 }
 236
 237 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 238 {
 239         return (struct arpt_entry *)(base + offset);
 240 }
 241
 242 unsigned int arpt_do_table(struct sk_buff *skb,
 243                            unsigned int hook,
 244                            const struct net_device *in,
 245                            const struct net_device *out,
 246                            struct xt_table *table)
 247 {
 248         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 249         unsigned int verdict = NF_DROP;
 250         const struct arphdr *arp;
 251         bool hotdrop = false;
 252         struct arpt_entry *e, *back;
 253         const char *indev, *outdev;
 254         void *table_base;
 255         const struct xt_table_info *private;
 256         struct xt_target_param tgpar;
 257
 258         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 259                 return NF_DROP;
 260
 261         indev = in ? in->name : nulldevname;
 262         outdev = out ? out->name : nulldevname;
 263
 264         read_lock_bh(&table->lock);
 265         private = table->private;
 266         table_base = (void *)private->entries[smp_processor_id()];
 267         e = get_entry(table_base, private->hook_entry[hook]);
 268         back = get_entry(table_base, private->underflow[hook]);
 269
 270         tgpar.in      = in;
 271         tgpar.out     = out;
 272         tgpar.hooknum = hook;
 273         tgpar.family  = NFPROTO_ARP;
 274
 275         arp = arp_hdr(skb);
 276         do {
 277                 if (arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 278                         struct arpt_entry_target *t;
 279                         int hdr_len;
 280
 281                         hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 282                                 (2 * skb->dev->addr_len);
 283                         ADD_COUNTER(e->counters, hdr_len, 1);
 284
 285                         t = arpt_get_target(e);
 286
 287                         /* Standard target? */
 288                         if (!t->u.kernel.target->target) {
 289                                 int v;
 290
 291                                 v = ((struct arpt_standard_target *)t)->verdict;
 292                                 if (v < 0) {
 293                                         /* Pop from stack? */
 294                                         if (v != ARPT_RETURN) {
 295                                                 verdict = (unsigned)(-v) - 1;
 296                                                 break;
 297                                         }
 298                                         e = back;
 299                                         back = get_entry(table_base,
 300                                                          back->comefrom);
 301                                         continue;
 302                                 }
 303                                 if (table_base + v
 304                                     != (void *)e + e->next_offset) {
 305                                         /* Save old back ptr in next entry */
 306                                         struct arpt_entry *next
 307                                                 = (void *)e + e->next_offset;
 308                                         next->comefrom =
 309                                                 (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                         } else {
 317                                 /* Targets which reenter must return
 318                                  * abs. verdicts
 319                                  */
 320                                 tgpar.target   = t->u.kernel.target;
 321                                 tgpar.targinfo = t->data;
 322                                 verdict = t->u.kernel.target->target(skb,
 323                                                                      &tgpar);
 324
 325                                 /* Target might have changed stuff. */
 326                                 arp = arp_hdr(skb);
 327
 328                                 if (verdict == ARPT_CONTINUE)
 329                                         e = (void *)e + e->next_offset;
 330                                 else
 331                                         /* Verdict */
 332                                         break;
 333                         }
 334                 } else {
 335                         e = (void *)e + e->next_offset;
 336                 }
 337         } while (!hotdrop);
 338         read_unlock_bh(&table->lock);
 339
 340         if (hotdrop)
 341                 return NF_DROP;
 342         else
 343                 return verdict;
 344 }
 345
 346 /* All zeroes == unconditional rule. */
 347 static inline int unconditional(const struct arpt_arp *arp)
 348 {
 349         unsigned int i;
 350
 351         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 352                 if (((__u32 *)arp)[i])
 353                         return 0;
 354
 355         return 1;
 356 }
 357
 358 /* Figures out from what hook each rule can be called: returns 0 if
 359  * there are loops.  Puts hook bitmask in comefrom.
 360  */
 361 static int mark_source_chains(struct xt_table_info *newinfo,
 362                               unsigned int valid_hooks, void *entry0)
 363 {
 364         unsigned int hook;
 365
 366         /* No recursion; use packet counter to save back ptrs (reset
 367          * to 0 as we leave), and comefrom to save source hook bitmask.
 368          */
 369         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 370                 unsigned int pos = newinfo->hook_entry[hook];
 371                 struct arpt_entry *e
 372                         = (struct arpt_entry *)(entry0 + pos);
 373
 374                 if (!(valid_hooks & (1 << hook)))
 375                         continue;
 376
 377                 /* Set initial back pointer. */
 378                 e->counters.pcnt = pos;
 379
 380                 for (;;) {
 381                         const struct arpt_standard_target *t
 382                                 = (void *)arpt_get_target(e);
 383                         int visited = e->comefrom & (1 << hook);
 384
 385                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 386                                 printk("arptables: loop hook %u pos %u %08X.\n",
 387                                        hook, pos, e->comefrom);
 388                                 return 0;
 389                         }
 390                         e->comefrom
 391                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 392
 393                         /* Unconditional return/END. */
 394                         if ((e->target_offset == sizeof(struct arpt_entry)
 395                             && (strcmp(t->target.u.user.name,
 396                                        ARPT_STANDARD_TARGET) == 0)
 397                             && t->verdict < 0
 398                             && unconditional(&e->arp)) || visited) {
 399                                 unsigned int oldpos, size;
 400
 401                                 if (t->verdict < -NF_MAX_VERDICT - 1) {
 402                                         duprintf("mark_source_chains: bad "
 403                                                 "negative verdict (%i)\n",
 404                                                                 t->verdict);
 405                                         return 0;
 406                                 }
 407
 408                                 /* Return: backtrack through the last
 409                                  * big jump.
 410                                  */
 411                                 do {
 412                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 413                                         oldpos = pos;
 414                                         pos = e->counters.pcnt;
 415                                         e->counters.pcnt = 0;
 416
 417                                         /* We're at the start. */
 418                                         if (pos == oldpos)
 419                                                 goto next;
 420
 421                                         e = (struct arpt_entry *)
 422                                                 (entry0 + pos);
 423                                 } while (oldpos == pos + e->next_offset);
 424
 425                                 /* Move along one */
 426                                 size = e->next_offset;
 427                                 e = (struct arpt_entry *)
 428                                         (entry0 + pos + size);
 429                                 e->counters.pcnt = pos;
 430                                 pos += size;
 431                         } else {
 432                                 int newpos = t->verdict;
 433
 434                                 if (strcmp(t->target.u.user.name,
 435                                            ARPT_STANDARD_TARGET) == 0
 436                                     && newpos >= 0) {
 437                                         if (newpos > newinfo->size -
 438                                                 sizeof(struct arpt_entry)) {
 439                                                 duprintf("mark_source_chains: "
 440                                                         "bad verdict (%i)\n",
 441                                                                 newpos);
 442                                                 return 0;
 443                                         }
 444
 445                                         /* This a jump; chase it. */
 446                                         duprintf("Jump rule %u -> %u\n",
 447                                                  pos, newpos);
 448                                 } else {
 449                                         /* ... this is a fallthru */
 450                                         newpos = pos + e->next_offset;
 451                                 }
 452                                 e = (struct arpt_entry *)
 453                                         (entry0 + newpos);
 454                                 e->counters.pcnt = pos;
 455                                 pos = newpos;
 456                         }
 457                 }
 458                 next:
 459                 duprintf("Finished chain %u\n", hook);
 460         }
 461         return 1;
 462 }
 463
 464 static inline int check_entry(struct arpt_entry *e, const char *name)
 465 {
 466         const struct arpt_entry_target *t;
 467
 468         if (!arp_checkentry(&e->arp)) {
 469                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 470                 return -EINVAL;
 471         }
 472
 473         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 474                 return -EINVAL;
 475
 476         t = arpt_get_target(e);
 477         if (e->target_offset + t->u.target_size > e->next_offset)
 478                 return -EINVAL;
 479
 480         return 0;
 481 }
 482
 483 static inline int check_target(struct arpt_entry *e, const char *name)
 484 {
 485         struct arpt_entry_target *t = arpt_get_target(e);
 486         int ret;
 487         struct xt_tgchk_param par = {
 488                 .table     = name,
 489                 .entryinfo = e,
 490                 .target    = t->u.kernel.target,
 491                 .targinfo  = t->data,
 492                 .hook_mask = e->comefrom,
 493                 .family    = NFPROTO_ARP,
 494         };
 495
 496         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 497         if (ret < 0) {
 498                 duprintf("arp_tables: check failed for `%s'.\n",
 499                          t->u.kernel.target->name);
 500                 return ret;
 501         }
 502         return 0;
 503 }
 504
 505 static inline int
 506 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 507                  unsigned int *i)
 508 {
 509         struct arpt_entry_target *t;
 510         struct xt_target *target;
 511         int ret;
 512
 513         ret = check_entry(e, name);
 514         if (ret)
 515                 return ret;
 516
 517         t = arpt_get_target(e);
 518         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 519                                                         t->u.user.name,
 520                                                         t->u.user.revision),
 521                                          "arpt_%s", t->u.user.name);
 522         if (IS_ERR(target) || !target) {
 523                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 524                 ret = target ? PTR_ERR(target) : -ENOENT;
 525                 goto out;
 526         }
 527         t->u.kernel.target = target;
 528
 529         ret = check_target(e, name);
 530         if (ret)
 531                 goto err;
 532
 533         (*i)++;
 534         return 0;
 535 err:
 536         module_put(t->u.kernel.target->me);
 537 out:
 538         return ret;
 539 }
 540
 541 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 542                                              struct xt_table_info *newinfo,
 543                                              unsigned char *base,
 544                                              unsigned char *limit,
 545                                              const unsigned int *hook_entries,
 546                                              const unsigned int *underflows,
 547                                              unsigned int *i)
 548 {
 549         unsigned int h;
 550
 551         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 552             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 553                 duprintf("Bad offset %p\n", e);
 554                 return -EINVAL;
 555         }
 556
 557         if (e->next_offset
 558             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 559                 duprintf("checking: element %p size %u\n",
 560                          e, e->next_offset);
 561                 return -EINVAL;
 562         }
 563
 564         /* Check hooks & underflows */
 565         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 566                 if ((unsigned char *)e - base == hook_entries[h])
 567                         newinfo->hook_entry[h] = hook_entries[h];
 568                 if ((unsigned char *)e - base == underflows[h])
 569                         newinfo->underflow[h] = underflows[h];
 570         }
 571
 572         /* FIXME: underflows must be unconditional, standard verdicts
 573            < 0 (not ARPT_RETURN). --RR */
 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, &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          * We dont care about preemption here.
 719          */
 720         curcpu = raw_smp_processor_id();
 721
 722         i = 0;
 723         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 724                            t->size,
 725                            set_entry_to_counter,
 726                            counters,
 727                            &i);
 728
 729         for_each_possible_cpu(cpu) {
 730                 if (cpu == curcpu)
 731                         continue;
 732                 i = 0;
 733                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 734                                    t->size,
 735                                    add_entry_to_counter,
 736                                    counters,
 737                                    &i);
 738         }
 739 }
 740
 741 static inline struct xt_counters *alloc_counters(struct xt_table *table)
 742 {
 743         unsigned int countersize;
 744         struct xt_counters *counters;
 745         const struct xt_table_info *private = table->private;
 746
 747         /* We need atomic snapshot of counters: rest doesn't change
 748          * (other than comefrom, which userspace doesn't care
 749          * about).
 750          */
 751         countersize = sizeof(struct xt_counters) * private->number;
 752         counters = vmalloc_node(countersize, numa_node_id());
 753
 754         if (counters == NULL)
 755                 return ERR_PTR(-ENOMEM);
 756
 757         /* First, sum counters... */
 758         write_lock_bh(&table->lock);
 759         get_counters(private, counters);
 760         write_unlock_bh(&table->lock);
 761
 762         return counters;
 763 }
 764
 765 static int copy_entries_to_user(unsigned int total_size,
 766                                 struct xt_table *table,
 767                                 void __user *userptr)
 768 {
 769         unsigned int off, num;
 770         struct arpt_entry *e;
 771         struct xt_counters *counters;
 772         struct xt_table_info *private = table->private;
 773         int ret = 0;
 774         void *loc_cpu_entry;
 775
 776         counters = alloc_counters(table);
 777         if (IS_ERR(counters))
 778                 return PTR_ERR(counters);
 779
 780         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 781         /* ... then copy entire thing ... */
 782         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 783                 ret = -EFAULT;
 784                 goto free_counters;
 785         }
 786
 787         /* FIXME: use iterator macros --RR */
 788         /* ... then go back and fix counters and names */
 789         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 790                 struct arpt_entry_target *t;
 791
 792                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 793                 if (copy_to_user(userptr + off
 794                                  + offsetof(struct arpt_entry, counters),
 795                                  &counters[num],
 796                                  sizeof(counters[num])) != 0) {
 797                         ret = -EFAULT;
 798                         goto free_counters;
 799                 }
 800
 801                 t = arpt_get_target(e);
 802                 if (copy_to_user(userptr + off + e->target_offset
 803                                  + offsetof(struct arpt_entry_target,
 804                                             u.user.name),
 805                                  t->u.kernel.target->name,
 806                                  strlen(t->u.kernel.target->name)+1) != 0) {
 807                         ret = -EFAULT;
 808                         goto free_counters;
 809                 }
 810         }
 811
 812  free_counters:
 813         vfree(counters);
 814         return ret;
 815 }
 816
 817 #ifdef CONFIG_COMPAT
 818 static void compat_standard_from_user(void *dst, void *src)
 819 {
 820         int v = *(compat_int_t *)src;
 821
 822         if (v > 0)
 823                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 824         memcpy(dst, &v, sizeof(v));
 825 }
 826
 827 static int compat_standard_to_user(void __user *dst, void *src)
 828 {
 829         compat_int_t cv = *(int *)src;
 830
 831         if (cv > 0)
 832                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 833         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 834 }
 835
 836 static int compat_calc_entry(struct arpt_entry *e,
 837                              const struct xt_table_info *info,
 838                              void *base, struct xt_table_info *newinfo)
 839 {
 840         struct arpt_entry_target *t;
 841         unsigned int entry_offset;
 842         int off, i, ret;
 843
 844         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 845         entry_offset = (void *)e - base;
 846
 847         t = arpt_get_target(e);
 848         off += xt_compat_target_offset(t->u.kernel.target);
 849         newinfo->size -= off;
 850         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 851         if (ret)
 852                 return ret;
 853
 854         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 855                 if (info->hook_entry[i] &&
 856                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 857                         newinfo->hook_entry[i] -= off;
 858                 if (info->underflow[i] &&
 859                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 860                         newinfo->underflow[i] -= off;
 861         }
 862         return 0;
 863 }
 864
 865 static int compat_table_info(const struct xt_table_info *info,
 866                              struct xt_table_info *newinfo)
 867 {
 868         void *loc_cpu_entry;
 869
 870         if (!newinfo || !info)
 871                 return -EINVAL;
 872
 873         /* we dont care about newinfo->entries[] */
 874         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 875         newinfo->initial_entries = 0;
 876         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 877         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 878                                   compat_calc_entry, info, loc_cpu_entry,
 879                                   newinfo);
 880 }
 881 #endif
 882
 883 static int get_info(struct net *net, void __user *user, int *len, int compat)
 884 {
 885         char name[ARPT_TABLE_MAXNAMELEN];
 886         struct xt_table *t;
 887         int ret;
 888
 889         if (*len != sizeof(struct arpt_getinfo)) {
 890                 duprintf("length %u != %Zu\n", *len,
 891                          sizeof(struct arpt_getinfo));
 892                 return -EINVAL;
 893         }
 894
 895         if (copy_from_user(name, user, sizeof(name)) != 0)
 896                 return -EFAULT;
 897
 898         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 899 #ifdef CONFIG_COMPAT
 900         if (compat)
 901                 xt_compat_lock(NFPROTO_ARP);
 902 #endif
 903         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 904                                     "arptable_%s", name);
 905         if (t && !IS_ERR(t)) {
 906                 struct arpt_getinfo info;
 907                 const struct xt_table_info *private = t->private;
 908
 909 #ifdef CONFIG_COMPAT
 910                 if (compat) {
 911                         struct xt_table_info tmp;
 912                         ret = compat_table_info(private, &tmp);
 913                         xt_compat_flush_offsets(NFPROTO_ARP);
 914                         private = &tmp;
 915                 }
 916 #endif
 917                 info.valid_hooks = t->valid_hooks;
 918                 memcpy(info.hook_entry, private->hook_entry,
 919                        sizeof(info.hook_entry));
 920                 memcpy(info.underflow, private->underflow,
 921                        sizeof(info.underflow));
 922                 info.num_entries = private->number;
 923                 info.size = private->size;
 924                 strcpy(info.name, name);
 925
 926                 if (copy_to_user(user, &info, *len) != 0)
 927                         ret = -EFAULT;
 928                 else
 929                         ret = 0;
 930                 xt_table_unlock(t);
 931                 module_put(t->me);
 932         } else
 933                 ret = t ? PTR_ERR(t) : -ENOENT;
 934 #ifdef CONFIG_COMPAT
 935         if (compat)
 936                 xt_compat_unlock(NFPROTO_ARP);
 937 #endif
 938         return ret;
 939 }
 940
 941 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 942                        int *len)
 943 {
 944         int ret;
 945         struct arpt_get_entries get;
 946         struct xt_table *t;
 947
 948         if (*len < sizeof(get)) {
 949                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 950                 return -EINVAL;
 951         }
 952         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 953                 return -EFAULT;
 954         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 955                 duprintf("get_entries: %u != %Zu\n", *len,
 956                          sizeof(struct arpt_get_entries) + get.size);
 957                 return -EINVAL;
 958         }
 959
 960         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 961         if (t && !IS_ERR(t)) {
 962                 const struct xt_table_info *private = t->private;
 963
 964                 duprintf("t->private->number = %u\n",
 965                          private->number);
 966                 if (get.size == private->size)
 967                         ret = copy_entries_to_user(private->size,
 968                                                    t, uptr->entrytable);
 969                 else {
 970                         duprintf("get_entries: I've got %u not %u!\n",
 971                                  private->size, get.size);
 972                         ret = -EAGAIN;
 973                 }
 974                 module_put(t->me);
 975                 xt_table_unlock(t);
 976         } else
 977                 ret = t ? PTR_ERR(t) : -ENOENT;
 978
 979         return ret;
 980 }
 981
 982 static int __do_replace(struct net *net, const char *name,
 983                         unsigned int valid_hooks,
 984                         struct xt_table_info *newinfo,
 985                         unsigned int num_counters,
 986                         void __user *counters_ptr)
 987 {
 988         int ret;
 989         struct xt_table *t;
 990         struct xt_table_info *oldinfo;
 991         struct xt_counters *counters;
 992         void *loc_cpu_old_entry;
 993
 994         ret = 0;
 995         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
 996                                 numa_node_id());
 997         if (!counters) {
 998                 ret = -ENOMEM;
 999                 goto out;
1000         }
1001
1002         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1003                                     "arptable_%s", name);
1004         if (!t || IS_ERR(t)) {
1005                 ret = t ? PTR_ERR(t) : -ENOENT;
1006                 goto free_newinfo_counters_untrans;
1007         }
1008
1009         /* You lied! */
1010         if (valid_hooks != t->valid_hooks) {
1011                 duprintf("Valid hook crap: %08X vs %08X\n",
1012                          valid_hooks, t->valid_hooks);
1013                 ret = -EINVAL;
1014                 goto put_module;
1015         }
1016
1017         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1018         if (!oldinfo)
1019                 goto put_module;
1020
1021         /* Update module usage count based on number of rules */
1022         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1023                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1024         if ((oldinfo->number > oldinfo->initial_entries) ||
1025             (newinfo->number <= oldinfo->initial_entries))
1026                 module_put(t->me);
1027         if ((oldinfo->number > oldinfo->initial_entries) &&
1028             (newinfo->number <= oldinfo->initial_entries))
1029                 module_put(t->me);
1030
1031         /* Get the old counters. */
1032         get_counters(oldinfo, counters);
1033         /* Decrease module usage counts and free resource */
1034         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1035         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1036                            NULL);
1037
1038         xt_free_table_info(oldinfo);
1039         if (copy_to_user(counters_ptr, counters,
1040                          sizeof(struct xt_counters) * num_counters) != 0)
1041                 ret = -EFAULT;
1042         vfree(counters);
1043         xt_table_unlock(t);
1044         return ret;
1045
1046  put_module:
1047         module_put(t->me);
1048         xt_table_unlock(t);
1049  free_newinfo_counters_untrans:
1050         vfree(counters);
1051  out:
1052         return ret;
1053 }
1054
1055 static int do_replace(struct net *net, void __user *user, unsigned int len)
1056 {
1057         int ret;
1058         struct arpt_replace tmp;
1059         struct xt_table_info *newinfo;
1060         void *loc_cpu_entry;
1061
1062         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1063                 return -EFAULT;
1064
1065         /* overflow check */
1066         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1067                 return -ENOMEM;
1068
1069         newinfo = xt_alloc_table_info(tmp.size);
1070         if (!newinfo)
1071                 return -ENOMEM;
1072
1073         /* choose the copy that is on our node/cpu */
1074         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1075         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1076                            tmp.size) != 0) {
1077                 ret = -EFAULT;
1078                 goto free_newinfo;
1079         }
1080
1081         ret = translate_table(tmp.name, tmp.valid_hooks,
1082                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1083                               tmp.hook_entry, tmp.underflow);
1084         if (ret != 0)
1085                 goto free_newinfo;
1086
1087         duprintf("arp_tables: Translated table\n");
1088
1089         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1090                            tmp.num_counters, tmp.counters);
1091         if (ret)
1092                 goto free_newinfo_untrans;
1093         return 0;
1094
1095  free_newinfo_untrans:
1096         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1097  free_newinfo:
1098         xt_free_table_info(newinfo);
1099         return ret;
1100 }
1101
1102 /* We're lazy, and add to the first CPU; overflow works its fey magic
1103  * and everything is OK.
1104  */
1105 static inline int add_counter_to_entry(struct arpt_entry *e,
1106                                        const struct xt_counters addme[],
1107                                        unsigned int *i)
1108 {
1109
1110         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1111
1112         (*i)++;
1113         return 0;
1114 }
1115
1116 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1117                            int compat)
1118 {
1119         unsigned int i;
1120         struct xt_counters_info tmp;
1121         struct xt_counters *paddc;
1122         unsigned int num_counters;
1123         const char *name;
1124         int size;
1125         void *ptmp;
1126         struct xt_table *t;
1127         const struct xt_table_info *private;
1128         int ret = 0;
1129         void *loc_cpu_entry;
1130 #ifdef CONFIG_COMPAT
1131         struct compat_xt_counters_info compat_tmp;
1132
1133         if (compat) {
1134                 ptmp = &compat_tmp;
1135                 size = sizeof(struct compat_xt_counters_info);
1136         } else
1137 #endif
1138         {
1139                 ptmp = &tmp;
1140                 size = sizeof(struct xt_counters_info);
1141         }
1142
1143         if (copy_from_user(ptmp, user, size) != 0)
1144                 return -EFAULT;
1145
1146 #ifdef CONFIG_COMPAT
1147         if (compat) {
1148                 num_counters = compat_tmp.num_counters;
1149                 name = compat_tmp.name;
1150         } else
1151 #endif
1152         {
1153                 num_counters = tmp.num_counters;
1154                 name = tmp.name;
1155         }
1156
1157         if (len != size + num_counters * sizeof(struct xt_counters))
1158                 return -EINVAL;
1159
1160         paddc = vmalloc_node(len - size, numa_node_id());
1161         if (!paddc)
1162                 return -ENOMEM;
1163
1164         if (copy_from_user(paddc, user + size, len - size) != 0) {
1165                 ret = -EFAULT;
1166                 goto free;
1167         }
1168
1169         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1170         if (!t || IS_ERR(t)) {
1171                 ret = t ? PTR_ERR(t) : -ENOENT;
1172                 goto free;
1173         }
1174
1175         write_lock_bh(&t->lock);
1176         private = t->private;
1177         if (private->number != num_counters) {
1178                 ret = -EINVAL;
1179                 goto unlock_up_free;
1180         }
1181
1182         i = 0;
1183         /* Choose the copy that is on our node */
1184         loc_cpu_entry = private->entries[smp_processor_id()];
1185         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1186                            private->size,
1187                            add_counter_to_entry,
1188                            paddc,
1189                            &i);
1190  unlock_up_free:
1191         write_unlock_bh(&t->lock);
1192         xt_table_unlock(t);
1193         module_put(t->me);
1194  free:
1195         vfree(paddc);
1196
1197         return ret;
1198 }
1199
1200 #ifdef CONFIG_COMPAT
1201 static inline int
1202 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1203 {
1204         struct arpt_entry_target *t;
1205
1206         if (i && (*i)-- == 0)
1207                 return 1;
1208
1209         t = compat_arpt_get_target(e);
1210         module_put(t->u.kernel.target->me);
1211         return 0;
1212 }
1213
1214 static inline int
1215 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1216                                   struct xt_table_info *newinfo,
1217                                   unsigned int *size,
1218                                   unsigned char *base,
1219                                   unsigned char *limit,
1220                                   unsigned int *hook_entries,
1221                                   unsigned int *underflows,
1222                                   unsigned int *i,
1223                                   const char *name)
1224 {
1225         struct arpt_entry_target *t;
1226         struct xt_target *target;
1227         unsigned int entry_offset;
1228         int ret, off, h;
1229
1230         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1231         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1232             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1233                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1234                 return -EINVAL;
1235         }
1236
1237         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1238                              sizeof(struct compat_xt_entry_target)) {
1239                 duprintf("checking: element %p size %u\n",
1240                          e, e->next_offset);
1241                 return -EINVAL;
1242         }
1243
1244         /* For purposes of check_entry casting the compat entry is fine */
1245         ret = check_entry((struct arpt_entry *)e, name);
1246         if (ret)
1247                 return ret;
1248
1249         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1250         entry_offset = (void *)e - (void *)base;
1251
1252         t = compat_arpt_get_target(e);
1253         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1254                                                         t->u.user.name,
1255                                                         t->u.user.revision),
1256                                          "arpt_%s", t->u.user.name);
1257         if (IS_ERR(target) || !target) {
1258                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1259                          t->u.user.name);
1260                 ret = target ? PTR_ERR(target) : -ENOENT;
1261                 goto out;
1262         }
1263         t->u.kernel.target = target;
1264
1265         off += xt_compat_target_offset(target);
1266         *size += off;
1267         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1268         if (ret)
1269                 goto release_target;
1270
1271         /* Check hooks & underflows */
1272         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1273                 if ((unsigned char *)e - base == hook_entries[h])
1274                         newinfo->hook_entry[h] = hook_entries[h];
1275                 if ((unsigned char *)e - base == underflows[h])
1276                         newinfo->underflow[h] = underflows[h];
1277         }
1278
1279         /* Clear counters and comefrom */
1280         memset(&e->counters, 0, sizeof(e->counters));
1281         e->comefrom = 0;
1282
1283         (*i)++;
1284         return 0;
1285
1286 release_target:
1287         module_put(t->u.kernel.target->me);
1288 out:
1289         return ret;
1290 }
1291
1292 static int
1293 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1294                             unsigned int *size, const char *name,
1295                             struct xt_table_info *newinfo, unsigned char *base)
1296 {
1297         struct arpt_entry_target *t;
1298         struct xt_target *target;
1299         struct arpt_entry *de;
1300         unsigned int origsize;
1301         int ret, h;
1302
1303         ret = 0;
1304         origsize = *size;
1305         de = (struct arpt_entry *)*dstptr;
1306         memcpy(de, e, sizeof(struct arpt_entry));
1307         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1308
1309         *dstptr += sizeof(struct arpt_entry);
1310         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1311
1312         de->target_offset = e->target_offset - (origsize - *size);
1313         t = compat_arpt_get_target(e);
1314         target = t->u.kernel.target;
1315         xt_compat_target_from_user(t, dstptr, size);
1316
1317         de->next_offset = e->next_offset - (origsize - *size);
1318         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1319                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1320                         newinfo->hook_entry[h] -= origsize - *size;
1321                 if ((unsigned char *)de - base < newinfo->underflow[h])
1322                         newinfo->underflow[h] -= origsize - *size;
1323         }
1324         return ret;
1325 }
1326
1327 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1328                                      unsigned int *i)
1329 {
1330         int ret;
1331
1332         ret = check_target(e, name);
1333         if (ret)
1334                 return ret;
1335
1336         (*i)++;
1337         return 0;
1338 }
1339
1340 static int translate_compat_table(const char *name,
1341                                   unsigned int valid_hooks,
1342                                   struct xt_table_info **pinfo,
1343                                   void **pentry0,
1344                                   unsigned int total_size,
1345                                   unsigned int number,
1346                                   unsigned int *hook_entries,
1347                                   unsigned int *underflows)
1348 {
1349         unsigned int i, j;
1350         struct xt_table_info *newinfo, *info;
1351         void *pos, *entry0, *entry1;
1352         unsigned int size;
1353         int ret;
1354
1355         info = *pinfo;
1356         entry0 = *pentry0;
1357         size = total_size;
1358         info->number = number;
1359
1360         /* Init all hooks to impossible value. */
1361         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1362                 info->hook_entry[i] = 0xFFFFFFFF;
1363                 info->underflow[i] = 0xFFFFFFFF;
1364         }
1365
1366         duprintf("translate_compat_table: size %u\n", info->size);
1367         j = 0;
1368         xt_compat_lock(NFPROTO_ARP);
1369         /* Walk through entries, checking offsets. */
1370         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1371                                         check_compat_entry_size_and_hooks,
1372                                         info, &size, entry0,
1373                                         entry0 + total_size,
1374                                         hook_entries, underflows, &j, name);
1375         if (ret != 0)
1376                 goto out_unlock;
1377
1378         ret = -EINVAL;
1379         if (j != number) {
1380                 duprintf("translate_compat_table: %u not %u entries\n",
1381                          j, number);
1382                 goto out_unlock;
1383         }
1384
1385         /* Check hooks all assigned */
1386         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1387                 /* Only hooks which are valid */
1388                 if (!(valid_hooks & (1 << i)))
1389                         continue;
1390                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1391                         duprintf("Invalid hook entry %u %u\n",
1392                                  i, hook_entries[i]);
1393                         goto out_unlock;
1394                 }
1395                 if (info->underflow[i] == 0xFFFFFFFF) {
1396                         duprintf("Invalid underflow %u %u\n",
1397                                  i, underflows[i]);
1398                         goto out_unlock;
1399                 }
1400         }
1401
1402         ret = -ENOMEM;
1403         newinfo = xt_alloc_table_info(size);
1404         if (!newinfo)
1405                 goto out_unlock;
1406
1407         newinfo->number = number;
1408         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1409                 newinfo->hook_entry[i] = info->hook_entry[i];
1410                 newinfo->underflow[i] = info->underflow[i];
1411         }
1412         entry1 = newinfo->entries[raw_smp_processor_id()];
1413         pos = entry1;
1414         size = total_size;
1415         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1416                                         compat_copy_entry_from_user,
1417                                         &pos, &size, name, newinfo, entry1);
1418         xt_compat_flush_offsets(NFPROTO_ARP);
1419         xt_compat_unlock(NFPROTO_ARP);
1420         if (ret)
1421                 goto free_newinfo;
1422
1423         ret = -ELOOP;
1424         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1425                 goto free_newinfo;
1426
1427         i = 0;
1428         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1429                                  name, &i);
1430         if (ret) {
1431                 j -= i;
1432                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1433                                                    compat_release_entry, &j);
1434                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1435                 xt_free_table_info(newinfo);
1436                 return ret;
1437         }
1438
1439         /* And one copy for every other CPU */
1440         for_each_possible_cpu(i)
1441                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1442                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1443
1444         *pinfo = newinfo;
1445         *pentry0 = entry1;
1446         xt_free_table_info(info);
1447         return 0;
1448
1449 free_newinfo:
1450         xt_free_table_info(newinfo);
1451 out:
1452         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1453         return ret;
1454 out_unlock:
1455         xt_compat_flush_offsets(NFPROTO_ARP);
1456         xt_compat_unlock(NFPROTO_ARP);
1457         goto out;
1458 }
1459
1460 struct compat_arpt_replace {
1461         char                            name[ARPT_TABLE_MAXNAMELEN];
1462         u32                             valid_hooks;
1463         u32                             num_entries;
1464         u32                             size;
1465         u32                             hook_entry[NF_ARP_NUMHOOKS];
1466         u32                             underflow[NF_ARP_NUMHOOKS];
1467         u32                             num_counters;
1468         compat_uptr_t                   counters;
1469         struct compat_arpt_entry        entries[0];
1470 };
1471
1472 static int compat_do_replace(struct net *net, void __user *user,
1473                              unsigned int len)
1474 {
1475         int ret;
1476         struct compat_arpt_replace tmp;
1477         struct xt_table_info *newinfo;
1478         void *loc_cpu_entry;
1479
1480         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1481                 return -EFAULT;
1482
1483         /* overflow check */
1484         if (tmp.size >= INT_MAX / num_possible_cpus())
1485                 return -ENOMEM;
1486         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1487                 return -ENOMEM;
1488
1489         newinfo = xt_alloc_table_info(tmp.size);
1490         if (!newinfo)
1491                 return -ENOMEM;
1492
1493         /* choose the copy that is on our node/cpu */
1494         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1495         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1496                 ret = -EFAULT;
1497                 goto free_newinfo;
1498         }
1499
1500         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1501                                      &newinfo, &loc_cpu_entry, tmp.size,
1502                                      tmp.num_entries, tmp.hook_entry,
1503                                      tmp.underflow);
1504         if (ret != 0)
1505                 goto free_newinfo;
1506
1507         duprintf("compat_do_replace: Translated table\n");
1508
1509         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1510                            tmp.num_counters, compat_ptr(tmp.counters));
1511         if (ret)
1512                 goto free_newinfo_untrans;
1513         return 0;
1514
1515  free_newinfo_untrans:
1516         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1517  free_newinfo:
1518         xt_free_table_info(newinfo);
1519         return ret;
1520 }
1521
1522 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1523                                   unsigned int len)
1524 {
1525         int ret;
1526
1527         if (!capable(CAP_NET_ADMIN))
1528                 return -EPERM;
1529
1530         switch (cmd) {
1531         case ARPT_SO_SET_REPLACE:
1532                 ret = compat_do_replace(sock_net(sk), user, len);
1533                 break;
1534
1535         case ARPT_SO_SET_ADD_COUNTERS:
1536                 ret = do_add_counters(sock_net(sk), user, len, 1);
1537                 break;
1538
1539         default:
1540                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1541                 ret = -EINVAL;
1542         }
1543
1544         return ret;
1545 }
1546
1547 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1548                                      compat_uint_t *size,
1549                                      struct xt_counters *counters,
1550                                      unsigned int *i)
1551 {
1552         struct arpt_entry_target *t;
1553         struct compat_arpt_entry __user *ce;
1554         u_int16_t target_offset, next_offset;
1555         compat_uint_t origsize;
1556         int ret;
1557
1558         ret = -EFAULT;
1559         origsize = *size;
1560         ce = (struct compat_arpt_entry __user *)*dstptr;
1561         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1562                 goto out;
1563
1564         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1565                 goto out;
1566
1567         *dstptr += sizeof(struct compat_arpt_entry);
1568         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1569
1570         target_offset = e->target_offset - (origsize - *size);
1571
1572         t = arpt_get_target(e);
1573         ret = xt_compat_target_to_user(t, dstptr, size);
1574         if (ret)
1575                 goto out;
1576         ret = -EFAULT;
1577         next_offset = e->next_offset - (origsize - *size);
1578         if (put_user(target_offset, &ce->target_offset))
1579                 goto out;
1580         if (put_user(next_offset, &ce->next_offset))
1581                 goto out;
1582
1583         (*i)++;
1584         return 0;
1585 out:
1586         return ret;
1587 }
1588
1589 static int compat_copy_entries_to_user(unsigned int total_size,
1590                                        struct xt_table *table,
1591                                        void __user *userptr)
1592 {
1593         struct xt_counters *counters;
1594         const struct xt_table_info *private = table->private;
1595         void __user *pos;
1596         unsigned int size;
1597         int ret = 0;
1598         void *loc_cpu_entry;
1599         unsigned int i = 0;
1600
1601         counters = alloc_counters(table);
1602         if (IS_ERR(counters))
1603                 return PTR_ERR(counters);
1604
1605         /* choose the copy on our node/cpu */
1606         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1607         pos = userptr;
1608         size = total_size;
1609         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1610                                  compat_copy_entry_to_user,
1611                                  &pos, &size, counters, &i);
1612         vfree(counters);
1613         return ret;
1614 }
1615
1616 struct compat_arpt_get_entries {
1617         char name[ARPT_TABLE_MAXNAMELEN];
1618         compat_uint_t size;
1619         struct compat_arpt_entry entrytable[0];
1620 };
1621
1622 static int compat_get_entries(struct net *net,
1623                               struct compat_arpt_get_entries __user *uptr,
1624                               int *len)
1625 {
1626         int ret;
1627         struct compat_arpt_get_entries get;
1628         struct xt_table *t;
1629
1630         if (*len < sizeof(get)) {
1631                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1632                 return -EINVAL;
1633         }
1634         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1635                 return -EFAULT;
1636         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1637                 duprintf("compat_get_entries: %u != %zu\n",
1638                          *len, sizeof(get) + get.size);
1639                 return -EINVAL;
1640         }
1641
1642         xt_compat_lock(NFPROTO_ARP);
1643         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1644         if (t && !IS_ERR(t)) {
1645                 const struct xt_table_info *private = t->private;
1646                 struct xt_table_info info;
1647
1648                 duprintf("t->private->number = %u\n", private->number);
1649                 ret = compat_table_info(private, &info);
1650                 if (!ret && get.size == info.size) {
1651                         ret = compat_copy_entries_to_user(private->size,
1652                                                           t, uptr->entrytable);
1653                 } else if (!ret) {
1654                         duprintf("compat_get_entries: I've got %u not %u!\n",
1655                                  private->size, get.size);
1656                         ret = -EAGAIN;
1657                 }
1658                 xt_compat_flush_offsets(NFPROTO_ARP);
1659                 module_put(t->me);
1660                 xt_table_unlock(t);
1661         } else
1662                 ret = t ? PTR_ERR(t) : -ENOENT;
1663
1664         xt_compat_unlock(NFPROTO_ARP);
1665         return ret;
1666 }
1667
1668 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1669
1670 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1671                                   int *len)
1672 {
1673         int ret;
1674
1675         if (!capable(CAP_NET_ADMIN))
1676                 return -EPERM;
1677
1678         switch (cmd) {
1679         case ARPT_SO_GET_INFO:
1680                 ret = get_info(sock_net(sk), user, len, 1);
1681                 break;
1682         case ARPT_SO_GET_ENTRIES:
1683                 ret = compat_get_entries(sock_net(sk), user, len);
1684                 break;
1685         default:
1686                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1687         }
1688         return ret;
1689 }
1690 #endif
1691
1692 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1693 {
1694         int ret;
1695
1696         if (!capable(CAP_NET_ADMIN))
1697                 return -EPERM;
1698
1699         switch (cmd) {
1700         case ARPT_SO_SET_REPLACE:
1701                 ret = do_replace(sock_net(sk), user, len);
1702                 break;
1703
1704         case ARPT_SO_SET_ADD_COUNTERS:
1705                 ret = do_add_counters(sock_net(sk), user, len, 0);
1706                 break;
1707
1708         default:
1709                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1710                 ret = -EINVAL;
1711         }
1712
1713         return ret;
1714 }
1715
1716 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1717 {
1718         int ret;
1719
1720         if (!capable(CAP_NET_ADMIN))
1721                 return -EPERM;
1722
1723         switch (cmd) {
1724         case ARPT_SO_GET_INFO:
1725                 ret = get_info(sock_net(sk), user, len, 0);
1726                 break;
1727
1728         case ARPT_SO_GET_ENTRIES:
1729                 ret = get_entries(sock_net(sk), user, len);
1730                 break;
1731
1732         case ARPT_SO_GET_REVISION_TARGET: {
1733                 struct xt_get_revision rev;
1734
1735                 if (*len != sizeof(rev)) {
1736                         ret = -EINVAL;
1737                         break;
1738                 }
1739                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1740                         ret = -EFAULT;
1741                         break;
1742                 }
1743
1744                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1745                                                          rev.revision, 1, &ret),
1746                                         "arpt_%s", rev.name);
1747                 break;
1748         }
1749
1750         default:
1751                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1752                 ret = -EINVAL;
1753         }
1754
1755         return ret;
1756 }
1757
1758 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1759                                      const struct arpt_replace *repl)
1760 {
1761         int ret;
1762         struct xt_table_info *newinfo;
1763         struct xt_table_info bootstrap
1764                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1765         void *loc_cpu_entry;
1766         struct xt_table *new_table;
1767
1768         newinfo = xt_alloc_table_info(repl->size);
1769         if (!newinfo) {
1770                 ret = -ENOMEM;
1771                 goto out;
1772         }
1773
1774         /* choose the copy on our node/cpu */
1775         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1776         memcpy(loc_cpu_entry, repl->entries, repl->size);
1777
1778         ret = translate_table(table->name, table->valid_hooks,
1779                               newinfo, loc_cpu_entry, repl->size,
1780                               repl->num_entries,
1781                               repl->hook_entry,
1782                               repl->underflow);
1783
1784         duprintf("arpt_register_table: translate table gives %d\n", ret);
1785         if (ret != 0)
1786                 goto out_free;
1787
1788         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1789         if (IS_ERR(new_table)) {
1790                 ret = PTR_ERR(new_table);
1791                 goto out_free;
1792         }
1793         return new_table;
1794
1795 out_free:
1796         xt_free_table_info(newinfo);
1797 out:
1798         return ERR_PTR(ret);
1799 }
1800
1801 void arpt_unregister_table(struct xt_table *table)
1802 {
1803         struct xt_table_info *private;
1804         void *loc_cpu_entry;
1805         struct module *table_owner = table->me;
1806
1807         private = xt_unregister_table(table);
1808
1809         /* Decrease module usage counts and free resources */
1810         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1811         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1812                            cleanup_entry, NULL);
1813         if (private->number > private->initial_entries)
1814                 module_put(table_owner);
1815         xt_free_table_info(private);
1816 }
1817
1818 /* The built-in targets: standard (NULL) and error. */
1819 static struct xt_target arpt_standard_target __read_mostly = {
1820         .name           = ARPT_STANDARD_TARGET,
1821         .targetsize     = sizeof(int),
1822         .family         = NFPROTO_ARP,
1823 #ifdef CONFIG_COMPAT
1824         .compatsize     = sizeof(compat_int_t),
1825         .compat_from_user = compat_standard_from_user,
1826         .compat_to_user = compat_standard_to_user,
1827 #endif
1828 };
1829
1830 static struct xt_target arpt_error_target __read_mostly = {
1831         .name           = ARPT_ERROR_TARGET,
1832         .target         = arpt_error,
1833         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1834         .family         = NFPROTO_ARP,
1835 };
1836
1837 static struct nf_sockopt_ops arpt_sockopts = {
1838         .pf             = PF_INET,
1839         .set_optmin     = ARPT_BASE_CTL,
1840         .set_optmax     = ARPT_SO_SET_MAX+1,
1841         .set            = do_arpt_set_ctl,
1842 #ifdef CONFIG_COMPAT
1843         .compat_set     = compat_do_arpt_set_ctl,
1844 #endif
1845         .get_optmin     = ARPT_BASE_CTL,
1846         .get_optmax     = ARPT_SO_GET_MAX+1,
1847         .get            = do_arpt_get_ctl,
1848 #ifdef CONFIG_COMPAT
1849         .compat_get     = compat_do_arpt_get_ctl,
1850 #endif
1851         .owner          = THIS_MODULE,
1852 };
1853
1854 static int __net_init arp_tables_net_init(struct net *net)
1855 {
1856         return xt_proto_init(net, NFPROTO_ARP);
1857 }
1858
1859 static void __net_exit arp_tables_net_exit(struct net *net)
1860 {
1861         xt_proto_fini(net, NFPROTO_ARP);
1862 }
1863
1864 static struct pernet_operations arp_tables_net_ops = {
1865         .init = arp_tables_net_init,
1866         .exit = arp_tables_net_exit,
1867 };
1868
1869 static int __init arp_tables_init(void)
1870 {
1871         int ret;
1872
1873         ret = register_pernet_subsys(&arp_tables_net_ops);
1874         if (ret < 0)
1875                 goto err1;
1876
1877         /* Noone else will be downing sem now, so we won't sleep */
1878         ret = xt_register_target(&arpt_standard_target);
1879         if (ret < 0)
1880                 goto err2;
1881         ret = xt_register_target(&arpt_error_target);
1882         if (ret < 0)
1883                 goto err3;
1884
1885         /* Register setsockopt */
1886         ret = nf_register_sockopt(&arpt_sockopts);
1887         if (ret < 0)
1888                 goto err4;
1889
1890         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1891         return 0;
1892
1893 err4:
1894         xt_unregister_target(&arpt_error_target);
1895 err3:
1896         xt_unregister_target(&arpt_standard_target);
1897 err2:
1898         unregister_pernet_subsys(&arp_tables_net_ops);
1899 err1:
1900         return ret;
1901 }
1902
1903 static void __exit arp_tables_fini(void)
1904 {
1905         nf_unregister_sockopt(&arpt_sockopts);
1906         xt_unregister_target(&arpt_error_target);
1907         xt_unregister_target(&arpt_standard_target);
1908         unregister_pernet_subsys(&arp_tables_net_ops);
1909 }
1910
1911 EXPORT_SYMBOL(arpt_register_table);
1912 EXPORT_SYMBOL(arpt_unregister_table);
1913 EXPORT_SYMBOL(arpt_do_table);
1914
1915 module_init(arp_tables_init);
1916 module_exit(arp_tables_fini);