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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 && unconditional(&e->arp)) ||
 391                             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 bool check_underflow(struct arpt_entry *e)
 537 {
 538         const struct arpt_entry_target *t;
 539         unsigned int verdict;
 540
 541         if (!unconditional(&e->arp))
 542                 return false;
 543         t = arpt_get_target(e);
 544         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 545                 return false;
 546         verdict = ((struct arpt_standard_target *)t)->verdict;
 547         verdict = -verdict - 1;
 548         return verdict == NF_DROP || verdict == NF_ACCEPT;
 549 }
 550
 551 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 552                                              struct xt_table_info *newinfo,
 553                                              unsigned char *base,
 554                                              unsigned char *limit,
 555                                              const unsigned int *hook_entries,
 556                                              const unsigned int *underflows,
 557                                              unsigned int valid_hooks,
 558                                              unsigned int *i)
 559 {
 560         unsigned int h;
 561
 562         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 563             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 564                 duprintf("Bad offset %p\n", e);
 565                 return -EINVAL;
 566         }
 567
 568         if (e->next_offset
 569             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 570                 duprintf("checking: element %p size %u\n",
 571                          e, e->next_offset);
 572                 return -EINVAL;
 573         }
 574
 575         /* Check hooks & underflows */
 576         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 577                 if (!(valid_hooks & (1 << h)))
 578                         continue;
 579                 if ((unsigned char *)e - base == hook_entries[h])
 580                         newinfo->hook_entry[h] = hook_entries[h];
 581                 if ((unsigned char *)e - base == underflows[h]) {
 582                         if (!check_underflow(e)) {
 583                                 pr_err("Underflows must be unconditional and "
 584                                        "use the STANDARD target with "
 585                                        "ACCEPT/DROP\n");
 586                                 return -EINVAL;
 587                         }
 588                         newinfo->underflow[h] = underflows[h];
 589                 }
 590         }
 591
 592         /* Clear counters and comefrom */
 593         e->counters = ((struct xt_counters) { 0, 0 });
 594         e->comefrom = 0;
 595
 596         (*i)++;
 597         return 0;
 598 }
 599
 600 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 601 {
 602         struct xt_tgdtor_param par;
 603         struct arpt_entry_target *t;
 604
 605         if (i && (*i)-- == 0)
 606                 return 1;
 607
 608         t = arpt_get_target(e);
 609         par.target   = t->u.kernel.target;
 610         par.targinfo = t->data;
 611         par.family   = NFPROTO_ARP;
 612         if (par.target->destroy != NULL)
 613                 par.target->destroy(&par);
 614         module_put(par.target->me);
 615         return 0;
 616 }
 617
 618 /* Checks and translates the user-supplied table segment (held in
 619  * newinfo).
 620  */
 621 static int translate_table(const char *name,
 622                            unsigned int valid_hooks,
 623                            struct xt_table_info *newinfo,
 624                            void *entry0,
 625                            unsigned int size,
 626                            unsigned int number,
 627                            const unsigned int *hook_entries,
 628                            const unsigned int *underflows)
 629 {
 630         unsigned int i;
 631         int ret;
 632
 633         newinfo->size = size;
 634         newinfo->number = number;
 635
 636         /* Init all hooks to impossible value. */
 637         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 638                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 639                 newinfo->underflow[i] = 0xFFFFFFFF;
 640         }
 641
 642         duprintf("translate_table: size %u\n", newinfo->size);
 643         i = 0;
 644
 645         /* Walk through entries, checking offsets. */
 646         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 647                                  check_entry_size_and_hooks,
 648                                  newinfo,
 649                                  entry0,
 650                                  entry0 + size,
 651                                  hook_entries, underflows, valid_hooks, &i);
 652         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 653         if (ret != 0)
 654                 return ret;
 655
 656         if (i != number) {
 657                 duprintf("translate_table: %u not %u entries\n",
 658                          i, number);
 659                 return -EINVAL;
 660         }
 661
 662         /* Check hooks all assigned */
 663         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 664                 /* Only hooks which are valid */
 665                 if (!(valid_hooks & (1 << i)))
 666                         continue;
 667                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 668                         duprintf("Invalid hook entry %u %u\n",
 669                                  i, hook_entries[i]);
 670                         return -EINVAL;
 671                 }
 672                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 673                         duprintf("Invalid underflow %u %u\n",
 674                                  i, underflows[i]);
 675                         return -EINVAL;
 676                 }
 677         }
 678
 679         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 680                 duprintf("Looping hook\n");
 681                 return -ELOOP;
 682         }
 683
 684         /* Finally, each sanity check must pass */
 685         i = 0;
 686         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 687                                  find_check_entry, name, size, &i);
 688
 689         if (ret != 0) {
 690                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 691                                 cleanup_entry, &i);
 692                 return ret;
 693         }
 694
 695         /* And one copy for every other CPU */
 696         for_each_possible_cpu(i) {
 697                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 698                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 699         }
 700
 701         return ret;
 702 }
 703
 704 /* Gets counters. */
 705 static inline int add_entry_to_counter(const struct arpt_entry *e,
 706                                        struct xt_counters total[],
 707                                        unsigned int *i)
 708 {
 709         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 710
 711         (*i)++;
 712         return 0;
 713 }
 714
 715 static inline int set_entry_to_counter(const struct arpt_entry *e,
 716                                        struct xt_counters total[],
 717                                        unsigned int *i)
 718 {
 719         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 720
 721         (*i)++;
 722         return 0;
 723 }
 724
 725 static void get_counters(const struct xt_table_info *t,
 726                          struct xt_counters counters[])
 727 {
 728         unsigned int cpu;
 729         unsigned int i;
 730         unsigned int curcpu;
 731
 732         /* Instead of clearing (by a previous call to memset())
 733          * the counters and using adds, we set the counters
 734          * with data used by 'current' CPU
 735          *
 736          * Bottom half has to be disabled to prevent deadlock
 737          * if new softirq were to run and call ipt_do_table
 738          */
 739         local_bh_disable();
 740         curcpu = smp_processor_id();
 741
 742         i = 0;
 743         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 744                            t->size,
 745                            set_entry_to_counter,
 746                            counters,
 747                            &i);
 748
 749         for_each_possible_cpu(cpu) {
 750                 if (cpu == curcpu)
 751                         continue;
 752                 i = 0;
 753                 xt_info_wrlock(cpu);
 754                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 755                                    t->size,
 756                                    add_entry_to_counter,
 757                                    counters,
 758                                    &i);
 759                 xt_info_wrunlock(cpu);
 760         }
 761         local_bh_enable();
 762 }
 763
 764 static struct xt_counters *alloc_counters(struct xt_table *table)
 765 {
 766         unsigned int countersize;
 767         struct xt_counters *counters;
 768         struct xt_table_info *private = table->private;
 769
 770         /* We need atomic snapshot of counters: rest doesn't change
 771          * (other than comefrom, which userspace doesn't care
 772          * about).
 773          */
 774         countersize = sizeof(struct xt_counters) * private->number;
 775         counters = vmalloc_node(countersize, numa_node_id());
 776
 777         if (counters == NULL)
 778                 return ERR_PTR(-ENOMEM);
 779
 780         get_counters(private, counters);
 781
 782         return counters;
 783 }
 784
 785 static int copy_entries_to_user(unsigned int total_size,
 786                                 struct xt_table *table,
 787                                 void __user *userptr)
 788 {
 789         unsigned int off, num;
 790         struct arpt_entry *e;
 791         struct xt_counters *counters;
 792         struct xt_table_info *private = table->private;
 793         int ret = 0;
 794         void *loc_cpu_entry;
 795
 796         counters = alloc_counters(table);
 797         if (IS_ERR(counters))
 798                 return PTR_ERR(counters);
 799
 800         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 801         /* ... then copy entire thing ... */
 802         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 803                 ret = -EFAULT;
 804                 goto free_counters;
 805         }
 806
 807         /* FIXME: use iterator macros --RR */
 808         /* ... then go back and fix counters and names */
 809         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 810                 struct arpt_entry_target *t;
 811
 812                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 813                 if (copy_to_user(userptr + off
 814                                  + offsetof(struct arpt_entry, counters),
 815                                  &counters[num],
 816                                  sizeof(counters[num])) != 0) {
 817                         ret = -EFAULT;
 818                         goto free_counters;
 819                 }
 820
 821                 t = arpt_get_target(e);
 822                 if (copy_to_user(userptr + off + e->target_offset
 823                                  + offsetof(struct arpt_entry_target,
 824                                             u.user.name),
 825                                  t->u.kernel.target->name,
 826                                  strlen(t->u.kernel.target->name)+1) != 0) {
 827                         ret = -EFAULT;
 828                         goto free_counters;
 829                 }
 830         }
 831
 832  free_counters:
 833         vfree(counters);
 834         return ret;
 835 }
 836
 837 #ifdef CONFIG_COMPAT
 838 static void compat_standard_from_user(void *dst, void *src)
 839 {
 840         int v = *(compat_int_t *)src;
 841
 842         if (v > 0)
 843                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 844         memcpy(dst, &v, sizeof(v));
 845 }
 846
 847 static int compat_standard_to_user(void __user *dst, void *src)
 848 {
 849         compat_int_t cv = *(int *)src;
 850
 851         if (cv > 0)
 852                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 853         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 854 }
 855
 856 static int compat_calc_entry(struct arpt_entry *e,
 857                              const struct xt_table_info *info,
 858                              void *base, struct xt_table_info *newinfo)
 859 {
 860         struct arpt_entry_target *t;
 861         unsigned int entry_offset;
 862         int off, i, ret;
 863
 864         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 865         entry_offset = (void *)e - base;
 866
 867         t = arpt_get_target(e);
 868         off += xt_compat_target_offset(t->u.kernel.target);
 869         newinfo->size -= off;
 870         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 871         if (ret)
 872                 return ret;
 873
 874         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 875                 if (info->hook_entry[i] &&
 876                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 877                         newinfo->hook_entry[i] -= off;
 878                 if (info->underflow[i] &&
 879                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 880                         newinfo->underflow[i] -= off;
 881         }
 882         return 0;
 883 }
 884
 885 static int compat_table_info(const struct xt_table_info *info,
 886                              struct xt_table_info *newinfo)
 887 {
 888         void *loc_cpu_entry;
 889
 890         if (!newinfo || !info)
 891                 return -EINVAL;
 892
 893         /* we dont care about newinfo->entries[] */
 894         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 895         newinfo->initial_entries = 0;
 896         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 897         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 898                                   compat_calc_entry, info, loc_cpu_entry,
 899                                   newinfo);
 900 }
 901 #endif
 902
 903 static int get_info(struct net *net, void __user *user, int *len, int compat)
 904 {
 905         char name[ARPT_TABLE_MAXNAMELEN];
 906         struct xt_table *t;
 907         int ret;
 908
 909         if (*len != sizeof(struct arpt_getinfo)) {
 910                 duprintf("length %u != %Zu\n", *len,
 911                          sizeof(struct arpt_getinfo));
 912                 return -EINVAL;
 913         }
 914
 915         if (copy_from_user(name, user, sizeof(name)) != 0)
 916                 return -EFAULT;
 917
 918         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 919 #ifdef CONFIG_COMPAT
 920         if (compat)
 921                 xt_compat_lock(NFPROTO_ARP);
 922 #endif
 923         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 924                                     "arptable_%s", name);
 925         if (t && !IS_ERR(t)) {
 926                 struct arpt_getinfo info;
 927                 const struct xt_table_info *private = t->private;
 928 #ifdef CONFIG_COMPAT
 929                 struct xt_table_info tmp;
 930
 931                 if (compat) {
 932                         ret = compat_table_info(private, &tmp);
 933                         xt_compat_flush_offsets(NFPROTO_ARP);
 934                         private = &tmp;
 935                 }
 936 #endif
 937                 info.valid_hooks = t->valid_hooks;
 938                 memcpy(info.hook_entry, private->hook_entry,
 939                        sizeof(info.hook_entry));
 940                 memcpy(info.underflow, private->underflow,
 941                        sizeof(info.underflow));
 942                 info.num_entries = private->number;
 943                 info.size = private->size;
 944                 strcpy(info.name, name);
 945
 946                 if (copy_to_user(user, &info, *len) != 0)
 947                         ret = -EFAULT;
 948                 else
 949                         ret = 0;
 950                 xt_table_unlock(t);
 951                 module_put(t->me);
 952         } else
 953                 ret = t ? PTR_ERR(t) : -ENOENT;
 954 #ifdef CONFIG_COMPAT
 955         if (compat)
 956                 xt_compat_unlock(NFPROTO_ARP);
 957 #endif
 958         return ret;
 959 }
 960
 961 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 962                        int *len)
 963 {
 964         int ret;
 965         struct arpt_get_entries get;
 966         struct xt_table *t;
 967
 968         if (*len < sizeof(get)) {
 969                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 970                 return -EINVAL;
 971         }
 972         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 973                 return -EFAULT;
 974         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 975                 duprintf("get_entries: %u != %Zu\n", *len,
 976                          sizeof(struct arpt_get_entries) + get.size);
 977                 return -EINVAL;
 978         }
 979
 980         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 981         if (t && !IS_ERR(t)) {
 982                 const struct xt_table_info *private = t->private;
 983
 984                 duprintf("t->private->number = %u\n",
 985                          private->number);
 986                 if (get.size == private->size)
 987                         ret = copy_entries_to_user(private->size,
 988                                                    t, uptr->entrytable);
 989                 else {
 990                         duprintf("get_entries: I've got %u not %u!\n",
 991                                  private->size, get.size);
 992                         ret = -EAGAIN;
 993                 }
 994                 module_put(t->me);
 995                 xt_table_unlock(t);
 996         } else
 997                 ret = t ? PTR_ERR(t) : -ENOENT;
 998
 999         return ret;
1000 }
1001
1002 static int __do_replace(struct net *net, const char *name,
1003                         unsigned int valid_hooks,
1004                         struct xt_table_info *newinfo,
1005                         unsigned int num_counters,
1006                         void __user *counters_ptr)
1007 {
1008         int ret;
1009         struct xt_table *t;
1010         struct xt_table_info *oldinfo;
1011         struct xt_counters *counters;
1012         void *loc_cpu_old_entry;
1013
1014         ret = 0;
1015         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
1016                                 numa_node_id());
1017         if (!counters) {
1018                 ret = -ENOMEM;
1019                 goto out;
1020         }
1021
1022         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1023                                     "arptable_%s", name);
1024         if (!t || IS_ERR(t)) {
1025                 ret = t ? PTR_ERR(t) : -ENOENT;
1026                 goto free_newinfo_counters_untrans;
1027         }
1028
1029         /* You lied! */
1030         if (valid_hooks != t->valid_hooks) {
1031                 duprintf("Valid hook crap: %08X vs %08X\n",
1032                          valid_hooks, t->valid_hooks);
1033                 ret = -EINVAL;
1034                 goto put_module;
1035         }
1036
1037         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1038         if (!oldinfo)
1039                 goto put_module;
1040
1041         /* Update module usage count based on number of rules */
1042         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1043                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1044         if ((oldinfo->number > oldinfo->initial_entries) ||
1045             (newinfo->number <= oldinfo->initial_entries))
1046                 module_put(t->me);
1047         if ((oldinfo->number > oldinfo->initial_entries) &&
1048             (newinfo->number <= oldinfo->initial_entries))
1049                 module_put(t->me);
1050
1051         /* Get the old counters, and synchronize with replace */
1052         get_counters(oldinfo, counters);
1053
1054         /* Decrease module usage counts and free resource */
1055         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1056         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1057                            NULL);
1058
1059         xt_free_table_info(oldinfo);
1060         if (copy_to_user(counters_ptr, counters,
1061                          sizeof(struct xt_counters) * num_counters) != 0)
1062                 ret = -EFAULT;
1063         vfree(counters);
1064         xt_table_unlock(t);
1065         return ret;
1066
1067  put_module:
1068         module_put(t->me);
1069         xt_table_unlock(t);
1070  free_newinfo_counters_untrans:
1071         vfree(counters);
1072  out:
1073         return ret;
1074 }
1075
1076 static int do_replace(struct net *net, void __user *user, unsigned int len)
1077 {
1078         int ret;
1079         struct arpt_replace tmp;
1080         struct xt_table_info *newinfo;
1081         void *loc_cpu_entry;
1082
1083         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1084                 return -EFAULT;
1085
1086         /* overflow check */
1087         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1088                 return -ENOMEM;
1089
1090         newinfo = xt_alloc_table_info(tmp.size);
1091         if (!newinfo)
1092                 return -ENOMEM;
1093
1094         /* choose the copy that is on our node/cpu */
1095         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1096         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1097                            tmp.size) != 0) {
1098                 ret = -EFAULT;
1099                 goto free_newinfo;
1100         }
1101
1102         ret = translate_table(tmp.name, tmp.valid_hooks,
1103                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1104                               tmp.hook_entry, tmp.underflow);
1105         if (ret != 0)
1106                 goto free_newinfo;
1107
1108         duprintf("arp_tables: Translated table\n");
1109
1110         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1111                            tmp.num_counters, tmp.counters);
1112         if (ret)
1113                 goto free_newinfo_untrans;
1114         return 0;
1115
1116  free_newinfo_untrans:
1117         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1118  free_newinfo:
1119         xt_free_table_info(newinfo);
1120         return ret;
1121 }
1122
1123 /* We're lazy, and add to the first CPU; overflow works its fey magic
1124  * and everything is OK. */
1125 static int
1126 add_counter_to_entry(struct arpt_entry *e,
1127                      const struct xt_counters addme[],
1128                      unsigned int *i)
1129 {
1130         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1131
1132         (*i)++;
1133         return 0;
1134 }
1135
1136 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1137                            int compat)
1138 {
1139         unsigned int i, curcpu;
1140         struct xt_counters_info tmp;
1141         struct xt_counters *paddc;
1142         unsigned int num_counters;
1143         const char *name;
1144         int size;
1145         void *ptmp;
1146         struct xt_table *t;
1147         const struct xt_table_info *private;
1148         int ret = 0;
1149         void *loc_cpu_entry;
1150 #ifdef CONFIG_COMPAT
1151         struct compat_xt_counters_info compat_tmp;
1152
1153         if (compat) {
1154                 ptmp = &compat_tmp;
1155                 size = sizeof(struct compat_xt_counters_info);
1156         } else
1157 #endif
1158         {
1159                 ptmp = &tmp;
1160                 size = sizeof(struct xt_counters_info);
1161         }
1162
1163         if (copy_from_user(ptmp, user, size) != 0)
1164                 return -EFAULT;
1165
1166 #ifdef CONFIG_COMPAT
1167         if (compat) {
1168                 num_counters = compat_tmp.num_counters;
1169                 name = compat_tmp.name;
1170         } else
1171 #endif
1172         {
1173                 num_counters = tmp.num_counters;
1174                 name = tmp.name;
1175         }
1176
1177         if (len != size + num_counters * sizeof(struct xt_counters))
1178                 return -EINVAL;
1179
1180         paddc = vmalloc_node(len - size, numa_node_id());
1181         if (!paddc)
1182                 return -ENOMEM;
1183
1184         if (copy_from_user(paddc, user + size, len - size) != 0) {
1185                 ret = -EFAULT;
1186                 goto free;
1187         }
1188
1189         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1190         if (!t || IS_ERR(t)) {
1191                 ret = t ? PTR_ERR(t) : -ENOENT;
1192                 goto free;
1193         }
1194
1195         local_bh_disable();
1196         private = t->private;
1197         if (private->number != num_counters) {
1198                 ret = -EINVAL;
1199                 goto unlock_up_free;
1200         }
1201
1202         i = 0;
1203         /* Choose the copy that is on our node */
1204         curcpu = smp_processor_id();
1205         loc_cpu_entry = private->entries[curcpu];
1206         xt_info_wrlock(curcpu);
1207         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1208                            private->size,
1209                            add_counter_to_entry,
1210                            paddc,
1211                            &i);
1212         xt_info_wrunlock(curcpu);
1213  unlock_up_free:
1214         local_bh_enable();
1215         xt_table_unlock(t);
1216         module_put(t->me);
1217  free:
1218         vfree(paddc);
1219
1220         return ret;
1221 }
1222
1223 #ifdef CONFIG_COMPAT
1224 static inline int
1225 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1226 {
1227         struct arpt_entry_target *t;
1228
1229         if (i && (*i)-- == 0)
1230                 return 1;
1231
1232         t = compat_arpt_get_target(e);
1233         module_put(t->u.kernel.target->me);
1234         return 0;
1235 }
1236
1237 static inline int
1238 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1239                                   struct xt_table_info *newinfo,
1240                                   unsigned int *size,
1241                                   unsigned char *base,
1242                                   unsigned char *limit,
1243                                   unsigned int *hook_entries,
1244                                   unsigned int *underflows,
1245                                   unsigned int *i,
1246                                   const char *name)
1247 {
1248         struct arpt_entry_target *t;
1249         struct xt_target *target;
1250         unsigned int entry_offset;
1251         int ret, off, h;
1252
1253         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1254         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1255             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1256                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1257                 return -EINVAL;
1258         }
1259
1260         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1261                              sizeof(struct compat_xt_entry_target)) {
1262                 duprintf("checking: element %p size %u\n",
1263                          e, e->next_offset);
1264                 return -EINVAL;
1265         }
1266
1267         /* For purposes of check_entry casting the compat entry is fine */
1268         ret = check_entry((struct arpt_entry *)e, name);
1269         if (ret)
1270                 return ret;
1271
1272         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1273         entry_offset = (void *)e - (void *)base;
1274
1275         t = compat_arpt_get_target(e);
1276         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1277                                                         t->u.user.name,
1278                                                         t->u.user.revision),
1279                                          "arpt_%s", t->u.user.name);
1280         if (IS_ERR(target) || !target) {
1281                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1282                          t->u.user.name);
1283                 ret = target ? PTR_ERR(target) : -ENOENT;
1284                 goto out;
1285         }
1286         t->u.kernel.target = target;
1287
1288         off += xt_compat_target_offset(target);
1289         *size += off;
1290         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1291         if (ret)
1292                 goto release_target;
1293
1294         /* Check hooks & underflows */
1295         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1296                 if ((unsigned char *)e - base == hook_entries[h])
1297                         newinfo->hook_entry[h] = hook_entries[h];
1298                 if ((unsigned char *)e - base == underflows[h])
1299                         newinfo->underflow[h] = underflows[h];
1300         }
1301
1302         /* Clear counters and comefrom */
1303         memset(&e->counters, 0, sizeof(e->counters));
1304         e->comefrom = 0;
1305
1306         (*i)++;
1307         return 0;
1308
1309 release_target:
1310         module_put(t->u.kernel.target->me);
1311 out:
1312         return ret;
1313 }
1314
1315 static int
1316 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1317                             unsigned int *size, const char *name,
1318                             struct xt_table_info *newinfo, unsigned char *base)
1319 {
1320         struct arpt_entry_target *t;
1321         struct xt_target *target;
1322         struct arpt_entry *de;
1323         unsigned int origsize;
1324         int ret, h;
1325
1326         ret = 0;
1327         origsize = *size;
1328         de = (struct arpt_entry *)*dstptr;
1329         memcpy(de, e, sizeof(struct arpt_entry));
1330         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1331
1332         *dstptr += sizeof(struct arpt_entry);
1333         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1334
1335         de->target_offset = e->target_offset - (origsize - *size);
1336         t = compat_arpt_get_target(e);
1337         target = t->u.kernel.target;
1338         xt_compat_target_from_user(t, dstptr, size);
1339
1340         de->next_offset = e->next_offset - (origsize - *size);
1341         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1342                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1343                         newinfo->hook_entry[h] -= origsize - *size;
1344                 if ((unsigned char *)de - base < newinfo->underflow[h])
1345                         newinfo->underflow[h] -= origsize - *size;
1346         }
1347         return ret;
1348 }
1349
1350 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1351                                      unsigned int *i)
1352 {
1353         int ret;
1354
1355         ret = check_target(e, name);
1356         if (ret)
1357                 return ret;
1358
1359         (*i)++;
1360         return 0;
1361 }
1362
1363 static int translate_compat_table(const char *name,
1364                                   unsigned int valid_hooks,
1365                                   struct xt_table_info **pinfo,
1366                                   void **pentry0,
1367                                   unsigned int total_size,
1368                                   unsigned int number,
1369                                   unsigned int *hook_entries,
1370                                   unsigned int *underflows)
1371 {
1372         unsigned int i, j;
1373         struct xt_table_info *newinfo, *info;
1374         void *pos, *entry0, *entry1;
1375         unsigned int size;
1376         int ret;
1377
1378         info = *pinfo;
1379         entry0 = *pentry0;
1380         size = total_size;
1381         info->number = number;
1382
1383         /* Init all hooks to impossible value. */
1384         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1385                 info->hook_entry[i] = 0xFFFFFFFF;
1386                 info->underflow[i] = 0xFFFFFFFF;
1387         }
1388
1389         duprintf("translate_compat_table: size %u\n", info->size);
1390         j = 0;
1391         xt_compat_lock(NFPROTO_ARP);
1392         /* Walk through entries, checking offsets. */
1393         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1394                                         check_compat_entry_size_and_hooks,
1395                                         info, &size, entry0,
1396                                         entry0 + total_size,
1397                                         hook_entries, underflows, &j, name);
1398         if (ret != 0)
1399                 goto out_unlock;
1400
1401         ret = -EINVAL;
1402         if (j != number) {
1403                 duprintf("translate_compat_table: %u not %u entries\n",
1404                          j, number);
1405                 goto out_unlock;
1406         }
1407
1408         /* Check hooks all assigned */
1409         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1410                 /* Only hooks which are valid */
1411                 if (!(valid_hooks & (1 << i)))
1412                         continue;
1413                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1414                         duprintf("Invalid hook entry %u %u\n",
1415                                  i, hook_entries[i]);
1416                         goto out_unlock;
1417                 }
1418                 if (info->underflow[i] == 0xFFFFFFFF) {
1419                         duprintf("Invalid underflow %u %u\n",
1420                                  i, underflows[i]);
1421                         goto out_unlock;
1422                 }
1423         }
1424
1425         ret = -ENOMEM;
1426         newinfo = xt_alloc_table_info(size);
1427         if (!newinfo)
1428                 goto out_unlock;
1429
1430         newinfo->number = number;
1431         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1432                 newinfo->hook_entry[i] = info->hook_entry[i];
1433                 newinfo->underflow[i] = info->underflow[i];
1434         }
1435         entry1 = newinfo->entries[raw_smp_processor_id()];
1436         pos = entry1;
1437         size = total_size;
1438         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1439                                         compat_copy_entry_from_user,
1440                                         &pos, &size, name, newinfo, entry1);
1441         xt_compat_flush_offsets(NFPROTO_ARP);
1442         xt_compat_unlock(NFPROTO_ARP);
1443         if (ret)
1444                 goto free_newinfo;
1445
1446         ret = -ELOOP;
1447         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1448                 goto free_newinfo;
1449
1450         i = 0;
1451         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1452                                  name, &i);
1453         if (ret) {
1454                 j -= i;
1455                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1456                                                    compat_release_entry, &j);
1457                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1458                 xt_free_table_info(newinfo);
1459                 return ret;
1460         }
1461
1462         /* And one copy for every other CPU */
1463         for_each_possible_cpu(i)
1464                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1465                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1466
1467         *pinfo = newinfo;
1468         *pentry0 = entry1;
1469         xt_free_table_info(info);
1470         return 0;
1471
1472 free_newinfo:
1473         xt_free_table_info(newinfo);
1474 out:
1475         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1476         return ret;
1477 out_unlock:
1478         xt_compat_flush_offsets(NFPROTO_ARP);
1479         xt_compat_unlock(NFPROTO_ARP);
1480         goto out;
1481 }
1482
1483 struct compat_arpt_replace {
1484         char                            name[ARPT_TABLE_MAXNAMELEN];
1485         u32                             valid_hooks;
1486         u32                             num_entries;
1487         u32                             size;
1488         u32                             hook_entry[NF_ARP_NUMHOOKS];
1489         u32                             underflow[NF_ARP_NUMHOOKS];
1490         u32                             num_counters;
1491         compat_uptr_t                   counters;
1492         struct compat_arpt_entry        entries[0];
1493 };
1494
1495 static int compat_do_replace(struct net *net, void __user *user,
1496                              unsigned int len)
1497 {
1498         int ret;
1499         struct compat_arpt_replace tmp;
1500         struct xt_table_info *newinfo;
1501         void *loc_cpu_entry;
1502
1503         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1504                 return -EFAULT;
1505
1506         /* overflow check */
1507         if (tmp.size >= INT_MAX / num_possible_cpus())
1508                 return -ENOMEM;
1509         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1510                 return -ENOMEM;
1511
1512         newinfo = xt_alloc_table_info(tmp.size);
1513         if (!newinfo)
1514                 return -ENOMEM;
1515
1516         /* choose the copy that is on our node/cpu */
1517         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1518         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1519                 ret = -EFAULT;
1520                 goto free_newinfo;
1521         }
1522
1523         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1524                                      &newinfo, &loc_cpu_entry, tmp.size,
1525                                      tmp.num_entries, tmp.hook_entry,
1526                                      tmp.underflow);
1527         if (ret != 0)
1528                 goto free_newinfo;
1529
1530         duprintf("compat_do_replace: Translated table\n");
1531
1532         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1533                            tmp.num_counters, compat_ptr(tmp.counters));
1534         if (ret)
1535                 goto free_newinfo_untrans;
1536         return 0;
1537
1538  free_newinfo_untrans:
1539         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1540  free_newinfo:
1541         xt_free_table_info(newinfo);
1542         return ret;
1543 }
1544
1545 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1546                                   unsigned int len)
1547 {
1548         int ret;
1549
1550         if (!capable(CAP_NET_ADMIN))
1551                 return -EPERM;
1552
1553         switch (cmd) {
1554         case ARPT_SO_SET_REPLACE:
1555                 ret = compat_do_replace(sock_net(sk), user, len);
1556                 break;
1557
1558         case ARPT_SO_SET_ADD_COUNTERS:
1559                 ret = do_add_counters(sock_net(sk), user, len, 1);
1560                 break;
1561
1562         default:
1563                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1564                 ret = -EINVAL;
1565         }
1566
1567         return ret;
1568 }
1569
1570 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1571                                      compat_uint_t *size,
1572                                      struct xt_counters *counters,
1573                                      unsigned int *i)
1574 {
1575         struct arpt_entry_target *t;
1576         struct compat_arpt_entry __user *ce;
1577         u_int16_t target_offset, next_offset;
1578         compat_uint_t origsize;
1579         int ret;
1580
1581         ret = -EFAULT;
1582         origsize = *size;
1583         ce = (struct compat_arpt_entry __user *)*dstptr;
1584         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1585                 goto out;
1586
1587         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1588                 goto out;
1589
1590         *dstptr += sizeof(struct compat_arpt_entry);
1591         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1592
1593         target_offset = e->target_offset - (origsize - *size);
1594
1595         t = arpt_get_target(e);
1596         ret = xt_compat_target_to_user(t, dstptr, size);
1597         if (ret)
1598                 goto out;
1599         ret = -EFAULT;
1600         next_offset = e->next_offset - (origsize - *size);
1601         if (put_user(target_offset, &ce->target_offset))
1602                 goto out;
1603         if (put_user(next_offset, &ce->next_offset))
1604                 goto out;
1605
1606         (*i)++;
1607         return 0;
1608 out:
1609         return ret;
1610 }
1611
1612 static int compat_copy_entries_to_user(unsigned int total_size,
1613                                        struct xt_table *table,
1614                                        void __user *userptr)
1615 {
1616         struct xt_counters *counters;
1617         const struct xt_table_info *private = table->private;
1618         void __user *pos;
1619         unsigned int size;
1620         int ret = 0;
1621         void *loc_cpu_entry;
1622         unsigned int i = 0;
1623
1624         counters = alloc_counters(table);
1625         if (IS_ERR(counters))
1626                 return PTR_ERR(counters);
1627
1628         /* choose the copy on our node/cpu */
1629         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1630         pos = userptr;
1631         size = total_size;
1632         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1633                                  compat_copy_entry_to_user,
1634                                  &pos, &size, counters, &i);
1635         vfree(counters);
1636         return ret;
1637 }
1638
1639 struct compat_arpt_get_entries {
1640         char name[ARPT_TABLE_MAXNAMELEN];
1641         compat_uint_t size;
1642         struct compat_arpt_entry entrytable[0];
1643 };
1644
1645 static int compat_get_entries(struct net *net,
1646                               struct compat_arpt_get_entries __user *uptr,
1647                               int *len)
1648 {
1649         int ret;
1650         struct compat_arpt_get_entries get;
1651         struct xt_table *t;
1652
1653         if (*len < sizeof(get)) {
1654                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1655                 return -EINVAL;
1656         }
1657         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1658                 return -EFAULT;
1659         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1660                 duprintf("compat_get_entries: %u != %zu\n",
1661                          *len, sizeof(get) + get.size);
1662                 return -EINVAL;
1663         }
1664
1665         xt_compat_lock(NFPROTO_ARP);
1666         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1667         if (t && !IS_ERR(t)) {
1668                 const struct xt_table_info *private = t->private;
1669                 struct xt_table_info info;
1670
1671                 duprintf("t->private->number = %u\n", private->number);
1672                 ret = compat_table_info(private, &info);
1673                 if (!ret && get.size == info.size) {
1674                         ret = compat_copy_entries_to_user(private->size,
1675                                                           t, uptr->entrytable);
1676                 } else if (!ret) {
1677                         duprintf("compat_get_entries: I've got %u not %u!\n",
1678                                  private->size, get.size);
1679                         ret = -EAGAIN;
1680                 }
1681                 xt_compat_flush_offsets(NFPROTO_ARP);
1682                 module_put(t->me);
1683                 xt_table_unlock(t);
1684         } else
1685                 ret = t ? PTR_ERR(t) : -ENOENT;
1686
1687         xt_compat_unlock(NFPROTO_ARP);
1688         return ret;
1689 }
1690
1691 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1692
1693 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1694                                   int *len)
1695 {
1696         int ret;
1697
1698         if (!capable(CAP_NET_ADMIN))
1699                 return -EPERM;
1700
1701         switch (cmd) {
1702         case ARPT_SO_GET_INFO:
1703                 ret = get_info(sock_net(sk), user, len, 1);
1704                 break;
1705         case ARPT_SO_GET_ENTRIES:
1706                 ret = compat_get_entries(sock_net(sk), user, len);
1707                 break;
1708         default:
1709                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1710         }
1711         return ret;
1712 }
1713 #endif
1714
1715 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1716 {
1717         int ret;
1718
1719         if (!capable(CAP_NET_ADMIN))
1720                 return -EPERM;
1721
1722         switch (cmd) {
1723         case ARPT_SO_SET_REPLACE:
1724                 ret = do_replace(sock_net(sk), user, len);
1725                 break;
1726
1727         case ARPT_SO_SET_ADD_COUNTERS:
1728                 ret = do_add_counters(sock_net(sk), user, len, 0);
1729                 break;
1730
1731         default:
1732                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1733                 ret = -EINVAL;
1734         }
1735
1736         return ret;
1737 }
1738
1739 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1740 {
1741         int ret;
1742
1743         if (!capable(CAP_NET_ADMIN))
1744                 return -EPERM;
1745
1746         switch (cmd) {
1747         case ARPT_SO_GET_INFO:
1748                 ret = get_info(sock_net(sk), user, len, 0);
1749                 break;
1750
1751         case ARPT_SO_GET_ENTRIES:
1752                 ret = get_entries(sock_net(sk), user, len);
1753                 break;
1754
1755         case ARPT_SO_GET_REVISION_TARGET: {
1756                 struct xt_get_revision rev;
1757
1758                 if (*len != sizeof(rev)) {
1759                         ret = -EINVAL;
1760                         break;
1761                 }
1762                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1763                         ret = -EFAULT;
1764                         break;
1765                 }
1766
1767                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1768                                                          rev.revision, 1, &ret),
1769                                         "arpt_%s", rev.name);
1770                 break;
1771         }
1772
1773         default:
1774                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1775                 ret = -EINVAL;
1776         }
1777
1778         return ret;
1779 }
1780
1781 struct xt_table *arpt_register_table(struct net *net,
1782                                      const struct xt_table *table,
1783                                      const struct arpt_replace *repl)
1784 {
1785         int ret;
1786         struct xt_table_info *newinfo;
1787         struct xt_table_info bootstrap
1788                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1789         void *loc_cpu_entry;
1790         struct xt_table *new_table;
1791
1792         newinfo = xt_alloc_table_info(repl->size);
1793         if (!newinfo) {
1794                 ret = -ENOMEM;
1795                 goto out;
1796         }
1797
1798         /* choose the copy on our node/cpu */
1799         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1800         memcpy(loc_cpu_entry, repl->entries, repl->size);
1801
1802         ret = translate_table(table->name, table->valid_hooks,
1803                               newinfo, loc_cpu_entry, repl->size,
1804                               repl->num_entries,
1805                               repl->hook_entry,
1806                               repl->underflow);
1807
1808         duprintf("arpt_register_table: translate table gives %d\n", ret);
1809         if (ret != 0)
1810                 goto out_free;
1811
1812         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1813         if (IS_ERR(new_table)) {
1814                 ret = PTR_ERR(new_table);
1815                 goto out_free;
1816         }
1817         return new_table;
1818
1819 out_free:
1820         xt_free_table_info(newinfo);
1821 out:
1822         return ERR_PTR(ret);
1823 }
1824
1825 void arpt_unregister_table(struct xt_table *table)
1826 {
1827         struct xt_table_info *private;
1828         void *loc_cpu_entry;
1829         struct module *table_owner = table->me;
1830
1831         private = xt_unregister_table(table);
1832
1833         /* Decrease module usage counts and free resources */
1834         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1835         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1836                            cleanup_entry, NULL);
1837         if (private->number > private->initial_entries)
1838                 module_put(table_owner);
1839         xt_free_table_info(private);
1840 }
1841
1842 /* The built-in targets: standard (NULL) and error. */
1843 static struct xt_target arpt_standard_target __read_mostly = {
1844         .name           = ARPT_STANDARD_TARGET,
1845         .targetsize     = sizeof(int),
1846         .family         = NFPROTO_ARP,
1847 #ifdef CONFIG_COMPAT
1848         .compatsize     = sizeof(compat_int_t),
1849         .compat_from_user = compat_standard_from_user,
1850         .compat_to_user = compat_standard_to_user,
1851 #endif
1852 };
1853
1854 static struct xt_target arpt_error_target __read_mostly = {
1855         .name           = ARPT_ERROR_TARGET,
1856         .target         = arpt_error,
1857         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1858         .family         = NFPROTO_ARP,
1859 };
1860
1861 static struct nf_sockopt_ops arpt_sockopts = {
1862         .pf             = PF_INET,
1863         .set_optmin     = ARPT_BASE_CTL,
1864         .set_optmax     = ARPT_SO_SET_MAX+1,
1865         .set            = do_arpt_set_ctl,
1866 #ifdef CONFIG_COMPAT
1867         .compat_set     = compat_do_arpt_set_ctl,
1868 #endif
1869         .get_optmin     = ARPT_BASE_CTL,
1870         .get_optmax     = ARPT_SO_GET_MAX+1,
1871         .get            = do_arpt_get_ctl,
1872 #ifdef CONFIG_COMPAT
1873         .compat_get     = compat_do_arpt_get_ctl,
1874 #endif
1875         .owner          = THIS_MODULE,
1876 };
1877
1878 static int __net_init arp_tables_net_init(struct net *net)
1879 {
1880         return xt_proto_init(net, NFPROTO_ARP);
1881 }
1882
1883 static void __net_exit arp_tables_net_exit(struct net *net)
1884 {
1885         xt_proto_fini(net, NFPROTO_ARP);
1886 }
1887
1888 static struct pernet_operations arp_tables_net_ops = {
1889         .init = arp_tables_net_init,
1890         .exit = arp_tables_net_exit,
1891 };
1892
1893 static int __init arp_tables_init(void)
1894 {
1895         int ret;
1896
1897         ret = register_pernet_subsys(&arp_tables_net_ops);
1898         if (ret < 0)
1899                 goto err1;
1900
1901         /* Noone else will be downing sem now, so we won't sleep */
1902         ret = xt_register_target(&arpt_standard_target);
1903         if (ret < 0)
1904                 goto err2;
1905         ret = xt_register_target(&arpt_error_target);
1906         if (ret < 0)
1907                 goto err3;
1908
1909         /* Register setsockopt */
1910         ret = nf_register_sockopt(&arpt_sockopts);
1911         if (ret < 0)
1912                 goto err4;
1913
1914         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1915         return 0;
1916
1917 err4:
1918         xt_unregister_target(&arpt_error_target);
1919 err3:
1920         xt_unregister_target(&arpt_standard_target);
1921 err2:
1922         unregister_pernet_subsys(&arp_tables_net_ops);
1923 err1:
1924         return ret;
1925 }
1926
1927 static void __exit arp_tables_fini(void)
1928 {
1929         nf_unregister_sockopt(&arpt_sockopts);
1930         xt_unregister_target(&arpt_error_target);
1931         xt_unregister_target(&arpt_standard_target);
1932         unregister_pernet_subsys(&arp_tables_net_ops);
1933 }
1934
1935 EXPORT_SYMBOL(arpt_register_table);
1936 EXPORT_SYMBOL(arpt_unregister_table);
1937 EXPORT_SYMBOL(arpt_do_table);
1938
1939 module_init(arp_tables_init);
1940 module_exit(arp_tables_fini);