net/ipv4/netfilter/arp_tables.c

   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  *
  10  */
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/capability.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/kmod.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/mutex.h>
  23 #include <linux/err.h>
  24 #include <net/compat.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter_arp/arp_tables.h>
  30 #include "../../netfilter/xt_repldata.h"
  31
  32 MODULE_LICENSE("GPL");
  33 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  34 MODULE_DESCRIPTION("arptables core");
  35
  36 /*#define DEBUG_ARP_TABLES*/
  37 /*#define DEBUG_ARP_TABLES_USER*/
  38
  39 #ifdef DEBUG_ARP_TABLES
  40 #define dprintf(format, args...)  printk(format , ## args)
  41 #else
  42 #define dprintf(format, args...)
  43 #endif
  44
  45 #ifdef DEBUG_ARP_TABLES_USER
  46 #define duprintf(format, args...) printk(format , ## args)
  47 #else
  48 #define duprintf(format, args...)
  49 #endif
  50
  51 #ifdef CONFIG_NETFILTER_DEBUG
  52 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  53 #else
  54 #define ARP_NF_ASSERT(x)
  55 #endif
  56
  57 void *arpt_alloc_initial_table(const struct xt_table *info)
  58 {
  59         return xt_alloc_initial_table(arpt, ARPT);
  60 }
  61 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  62
  63 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  64                                       const char *hdr_addr, int len)
  65 {
  66         int i, ret;
  67
  68         if (len > ARPT_DEV_ADDR_LEN_MAX)
  69                 len = ARPT_DEV_ADDR_LEN_MAX;
  70
  71         ret = 0;
  72         for (i = 0; i < len; i++)
  73                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  74
  75         return (ret != 0);
  76 }
  77
  78 /*
  79  * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  80  * Some arches dont care, unrolling the loop is a win on them.
  81  * For other arches, we only have a 16bit alignement.
  82  */
  83 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  84 {
  85 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  86         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  87 #else
  88         unsigned long ret = 0;
  89         const u16 *a = (const u16 *)_a;
  90         const u16 *b = (const u16 *)_b;
  91         const u16 *mask = (const u16 *)_mask;
  92         int i;
  93
  94         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  95                 ret |= (a[i] ^ b[i]) & mask[i];
  96 #endif
  97         return ret;
  98 }
  99
 100 /* Returns whether packet matches rule or not. */
 101 static inline int arp_packet_match(const struct arphdr *arphdr,
 102                                    struct net_device *dev,
 103                                    const char *indev,
 104                                    const char *outdev,
 105                                    const struct arpt_arp *arpinfo)
 106 {
 107         const char *arpptr = (char *)(arphdr + 1);
 108         const char *src_devaddr, *tgt_devaddr;
 109         __be32 src_ipaddr, tgt_ipaddr;
 110         long ret;
 111
 112 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 113
 114         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 115                   ARPT_INV_ARPOP)) {
 116                 dprintf("ARP operation field mismatch.\n");
 117                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 118                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 119                 return 0;
 120         }
 121
 122         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 123                   ARPT_INV_ARPHRD)) {
 124                 dprintf("ARP hardware address format mismatch.\n");
 125                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 126                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 127                 return 0;
 128         }
 129
 130         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 131                   ARPT_INV_ARPPRO)) {
 132                 dprintf("ARP protocol address format mismatch.\n");
 133                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 134                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 135                 return 0;
 136         }
 137
 138         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 139                   ARPT_INV_ARPHLN)) {
 140                 dprintf("ARP hardware address length mismatch.\n");
 141                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 142                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 143                 return 0;
 144         }
 145
 146         src_devaddr = arpptr;
 147         arpptr += dev->addr_len;
 148         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 149         arpptr += sizeof(u32);
 150         tgt_devaddr = arpptr;
 151         arpptr += dev->addr_len;
 152         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 153
 154         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 155                   ARPT_INV_SRCDEVADDR) ||
 156             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 157                   ARPT_INV_TGTDEVADDR)) {
 158                 dprintf("Source or target device address mismatch.\n");
 159
 160                 return 0;
 161         }
 162
 163         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 164                   ARPT_INV_SRCIP) ||
 165             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 166                   ARPT_INV_TGTIP)) {
 167                 dprintf("Source or target IP address mismatch.\n");
 168
 169                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 170                         &src_ipaddr,
 171                         &arpinfo->smsk.s_addr,
 172                         &arpinfo->src.s_addr,
 173                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 174                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 175                         &tgt_ipaddr,
 176                         &arpinfo->tmsk.s_addr,
 177                         &arpinfo->tgt.s_addr,
 178                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 179                 return 0;
 180         }
 181
 182         /* Look for ifname matches.  */
 183         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 184
 185         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 186                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 187                         indev, arpinfo->iniface,
 188                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 189                 return 0;
 190         }
 191
 192         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 193
 194         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 195                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 196                         outdev, arpinfo->outiface,
 197                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 198                 return 0;
 199         }
 200
 201         return 1;
 202 #undef FWINV
 203 }
 204
 205 static inline int arp_checkentry(const struct arpt_arp *arp)
 206 {
 207         if (arp->flags & ~ARPT_F_MASK) {
 208                 duprintf("Unknown flag bits set: %08X\n",
 209                          arp->flags & ~ARPT_F_MASK);
 210                 return 0;
 211         }
 212         if (arp->invflags & ~ARPT_INV_MASK) {
 213                 duprintf("Unknown invflag bits set: %08X\n",
 214                          arp->invflags & ~ARPT_INV_MASK);
 215                 return 0;
 216         }
 217
 218         return 1;
 219 }
 220
 221 static unsigned int
 222 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 223 {
 224         if (net_ratelimit())
 225                 pr_err("arp_tables: error: '%s'\n",
 226                        (const char *)par->targinfo);
 227
 228         return NF_DROP;
 229 }
 230
 231 static inline const struct arpt_entry_target *
 232 arpt_get_target_c(const struct arpt_entry *e)
 233 {
 234         return arpt_get_target((struct arpt_entry *)e);
 235 }
 236
 237 static inline struct arpt_entry *
 238 get_entry(const void *base, unsigned int offset)
 239 {
 240         return (struct arpt_entry *)(base + offset);
 241 }
 242
 243 static inline __pure
 244 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 245 {
 246         return (void *)entry + entry->next_offset;
 247 }
 248
 249 unsigned int arpt_do_table(struct sk_buff *skb,
 250                            unsigned int hook,
 251                            const struct net_device *in,
 252                            const struct net_device *out,
 253                            struct xt_table *table)
 254 {
 255         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 256         unsigned int verdict = NF_DROP;
 257         const struct arphdr *arp;
 258         struct arpt_entry *e, *back;
 259         const char *indev, *outdev;
 260         void *table_base;
 261         const struct xt_table_info *private;
 262         struct xt_action_param acpar;
 263
 264         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 265                 return NF_DROP;
 266
 267         indev = in ? in->name : nulldevname;
 268         outdev = out ? out->name : nulldevname;
 269
 270         xt_info_rdlock_bh();
 271         private = table->private;
 272         table_base = private->entries[smp_processor_id()];
 273
 274         e = get_entry(table_base, private->hook_entry[hook]);
 275         back = get_entry(table_base, private->underflow[hook]);
 276
 277         acpar.in      = in;
 278         acpar.out     = out;
 279         acpar.hooknum = hook;
 280         acpar.family  = NFPROTO_ARP;
 281         acpar.hotdrop = false;
 282
 283         arp = arp_hdr(skb);
 284         do {
 285                 const struct arpt_entry_target *t;
 286
 287                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 288                         e = arpt_next_entry(e);
 289                         continue;
 290                 }
 291
 292                 ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
 293
 294                 t = arpt_get_target_c(e);
 295
 296                 /* Standard target? */
 297                 if (!t->u.kernel.target->target) {
 298                         int v;
 299
 300                         v = ((struct arpt_standard_target *)t)->verdict;
 301                         if (v < 0) {
 302                                 /* Pop from stack? */
 303                                 if (v != ARPT_RETURN) {
 304                                         verdict = (unsigned)(-v) - 1;
 305                                         break;
 306                                 }
 307                                 e = back;
 308                                 back = get_entry(table_base, back->comefrom);
 309                                 continue;
 310                         }
 311                         if (table_base + v
 312                             != arpt_next_entry(e)) {
 313                                 /* Save old back ptr in next entry */
 314                                 struct arpt_entry *next = arpt_next_entry(e);
 315                                 next->comefrom = (void *)back - table_base;
 316
 317                                 /* set back pointer to next entry */
 318                                 back = next;
 319                         }
 320
 321                         e = get_entry(table_base, v);
 322                         continue;
 323                 }
 324
 325                 /* Targets which reenter must return
 326                  * abs. verdicts
 327                  */
 328                 acpar.target   = t->u.kernel.target;
 329                 acpar.targinfo = t->data;
 330                 verdict = t->u.kernel.target->target(skb, &acpar);
 331
 332                 /* Target might have changed stuff. */
 333                 arp = arp_hdr(skb);
 334
 335                 if (verdict == ARPT_CONTINUE)
 336                         e = arpt_next_entry(e);
 337                 else
 338                         /* Verdict */
 339                         break;
 340         } while (!acpar.hotdrop);
 341         xt_info_rdunlock_bh();
 342
 343         if (acpar.hotdrop)
 344                 return NF_DROP;
 345         else
 346                 return verdict;
 347 }
 348
 349 /* All zeroes == unconditional rule. */
 350 static inline bool unconditional(const struct arpt_arp *arp)
 351 {
 352         static const struct arpt_arp uncond;
 353
 354         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 355 }
 356
 357 /* Figures out from what hook each rule can be called: returns 0 if
 358  * there are loops.  Puts hook bitmask in comefrom.
 359  */
 360 static int mark_source_chains(const struct xt_table_info *newinfo,
 361                               unsigned int valid_hooks, void *entry0)
 362 {
 363         unsigned int hook;
 364
 365         /* No recursion; use packet counter to save back ptrs (reset
 366          * to 0 as we leave), and comefrom to save source hook bitmask.
 367          */
 368         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 369                 unsigned int pos = newinfo->hook_entry[hook];
 370                 struct arpt_entry *e
 371                         = (struct arpt_entry *)(entry0 + pos);
 372
 373                 if (!(valid_hooks & (1 << hook)))
 374                         continue;
 375
 376                 /* Set initial back pointer. */
 377                 e->counters.pcnt = pos;
 378
 379                 for (;;) {
 380                         const struct arpt_standard_target *t
 381                                 = (void *)arpt_get_target_c(e);
 382                         int visited = e->comefrom & (1 << hook);
 383
 384                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 385                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 386                                        hook, pos, e->comefrom);
 387                                 return 0;
 388                         }
 389                         e->comefrom
 390                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 391
 392                         /* Unconditional return/END. */
 393                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 394                              (strcmp(t->target.u.user.name,
 395                                      ARPT_STANDARD_TARGET) == 0) &&
 396                              t->verdict < 0 && unconditional(&e->arp)) ||
 397                             visited) {
 398                                 unsigned int oldpos, size;
 399
 400                                 if ((strcmp(t->target.u.user.name,
 401                                             ARPT_STANDARD_TARGET) == 0) &&
 402                                     t->verdict < -NF_MAX_VERDICT - 1) {
 403                                         duprintf("mark_source_chains: bad "
 404                                                 "negative verdict (%i)\n",
 405                                                                 t->verdict);
 406                                         return 0;
 407                                 }
 408
 409                                 /* Return: backtrack through the last
 410                                  * big jump.
 411                                  */
 412                                 do {
 413                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 414                                         oldpos = pos;
 415                                         pos = e->counters.pcnt;
 416                                         e->counters.pcnt = 0;
 417
 418                                         /* We're at the start. */
 419                                         if (pos == oldpos)
 420                                                 goto next;
 421
 422                                         e = (struct arpt_entry *)
 423                                                 (entry0 + pos);
 424                                 } while (oldpos == pos + e->next_offset);
 425
 426                                 /* Move along one */
 427                                 size = e->next_offset;
 428                                 e = (struct arpt_entry *)
 429                                         (entry0 + pos + size);
 430                                 e->counters.pcnt = pos;
 431                                 pos += size;
 432                         } else {
 433                                 int newpos = t->verdict;
 434
 435                                 if (strcmp(t->target.u.user.name,
 436                                            ARPT_STANDARD_TARGET) == 0 &&
 437                                     newpos >= 0) {
 438                                         if (newpos > newinfo->size -
 439                                                 sizeof(struct arpt_entry)) {
 440                                                 duprintf("mark_source_chains: "
 441                                                         "bad verdict (%i)\n",
 442                                                                 newpos);
 443                                                 return 0;
 444                                         }
 445
 446                                         /* This a jump; chase it. */
 447                                         duprintf("Jump rule %u -> %u\n",
 448                                                  pos, newpos);
 449                                 } else {
 450                                         /* ... this is a fallthru */
 451                                         newpos = pos + e->next_offset;
 452                                 }
 453                                 e = (struct arpt_entry *)
 454                                         (entry0 + newpos);
 455                                 e->counters.pcnt = pos;
 456                                 pos = newpos;
 457                         }
 458                 }
 459                 next:
 460                 duprintf("Finished chain %u\n", hook);
 461         }
 462         return 1;
 463 }
 464
 465 static inline int check_entry(const struct arpt_entry *e, const char *name)
 466 {
 467         const struct arpt_entry_target *t;
 468
 469         if (!arp_checkentry(&e->arp)) {
 470                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 471                 return -EINVAL;
 472         }
 473
 474         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 475                 return -EINVAL;
 476
 477         t = arpt_get_target_c(e);
 478         if (e->target_offset + t->u.target_size > e->next_offset)
 479                 return -EINVAL;
 480
 481         return 0;
 482 }
 483
 484 static inline int check_target(struct arpt_entry *e, const char *name)
 485 {
 486         struct arpt_entry_target *t = arpt_get_target(e);
 487         int ret;
 488         struct xt_tgchk_param par = {
 489                 .table     = name,
 490                 .entryinfo = e,
 491                 .target    = t->u.kernel.target,
 492                 .targinfo  = t->data,
 493                 .hook_mask = e->comefrom,
 494                 .family    = NFPROTO_ARP,
 495         };
 496
 497         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 498         if (ret < 0) {
 499                 duprintf("arp_tables: check failed for `%s'.\n",
 500                          t->u.kernel.target->name);
 501                 return ret;
 502         }
 503         return 0;
 504 }
 505
 506 static inline int
 507 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 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 = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 519                                         t->u.user.revision);
 520         if (IS_ERR(target)) {
 521                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 522                 ret = PTR_ERR(target);
 523                 goto out;
 524         }
 525         t->u.kernel.target = target;
 526
 527         ret = check_target(e, name);
 528         if (ret)
 529                 goto err;
 530         return 0;
 531 err:
 532         module_put(t->u.kernel.target->me);
 533 out:
 534         return ret;
 535 }
 536
 537 static bool check_underflow(const struct arpt_entry *e)
 538 {
 539         const struct arpt_entry_target *t;
 540         unsigned int verdict;
 541
 542         if (!unconditional(&e->arp))
 543                 return false;
 544         t = arpt_get_target_c(e);
 545         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 546                 return false;
 547         verdict = ((struct arpt_standard_target *)t)->verdict;
 548         verdict = -verdict - 1;
 549         return verdict == NF_DROP || verdict == NF_ACCEPT;
 550 }
 551
 552 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 553                                              struct xt_table_info *newinfo,
 554                                              const unsigned char *base,
 555                                              const unsigned char *limit,
 556                                              const unsigned int *hook_entries,
 557                                              const unsigned int *underflows,
 558                                              unsigned int valid_hooks)
 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         return 0;
 596 }
 597
 598 static inline void cleanup_entry(struct arpt_entry *e)
 599 {
 600         struct xt_tgdtor_param par;
 601         struct arpt_entry_target *t;
 602
 603         t = arpt_get_target(e);
 604         par.target   = t->u.kernel.target;
 605         par.targinfo = t->data;
 606         par.family   = NFPROTO_ARP;
 607         if (par.target->destroy != NULL)
 608                 par.target->destroy(&par);
 609         module_put(par.target->me);
 610 }
 611
 612 /* Checks and translates the user-supplied table segment (held in
 613  * newinfo).
 614  */
 615 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 616                            const struct arpt_replace *repl)
 617 {
 618         struct arpt_entry *iter;
 619         unsigned int i;
 620         int ret = 0;
 621
 622         newinfo->size = repl->size;
 623         newinfo->number = repl->num_entries;
 624
 625         /* Init all hooks to impossible value. */
 626         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 627                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 628                 newinfo->underflow[i] = 0xFFFFFFFF;
 629         }
 630
 631         duprintf("translate_table: size %u\n", newinfo->size);
 632         i = 0;
 633
 634         /* Walk through entries, checking offsets. */
 635         xt_entry_foreach(iter, entry0, newinfo->size) {
 636                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 637                                                  entry0 + repl->size,
 638                                                  repl->hook_entry,
 639                                                  repl->underflow,
 640                                                  repl->valid_hooks);
 641                 if (ret != 0)
 642                         break;
 643                 ++i;
 644                 if (strcmp(arpt_get_target(iter)->u.user.name,
 645                     XT_ERROR_TARGET) == 0)
 646                         ++newinfo->stacksize;
 647         }
 648         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 649         if (ret != 0)
 650                 return ret;
 651
 652         if (i != repl->num_entries) {
 653                 duprintf("translate_table: %u not %u entries\n",
 654                          i, repl->num_entries);
 655                 return -EINVAL;
 656         }
 657
 658         /* Check hooks all assigned */
 659         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 660                 /* Only hooks which are valid */
 661                 if (!(repl->valid_hooks & (1 << i)))
 662                         continue;
 663                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 664                         duprintf("Invalid hook entry %u %u\n",
 665                                  i, repl->hook_entry[i]);
 666                         return -EINVAL;
 667                 }
 668                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 669                         duprintf("Invalid underflow %u %u\n",
 670                                  i, repl->underflow[i]);
 671                         return -EINVAL;
 672                 }
 673         }
 674
 675         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 676                 duprintf("Looping hook\n");
 677                 return -ELOOP;
 678         }
 679
 680         /* Finally, each sanity check must pass */
 681         i = 0;
 682         xt_entry_foreach(iter, entry0, newinfo->size) {
 683                 ret = find_check_entry(iter, repl->name, repl->size);
 684                 if (ret != 0)
 685                         break;
 686                 ++i;
 687         }
 688
 689         if (ret != 0) {
 690                 xt_entry_foreach(iter, entry0, newinfo->size) {
 691                         if (i-- == 0)
 692                                 break;
 693                         cleanup_entry(iter);
 694                 }
 695                 return ret;
 696         }
 697
 698         /* And one copy for every other CPU */
 699         for_each_possible_cpu(i) {
 700                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 701                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 702         }
 703
 704         return ret;
 705 }
 706
 707 static void get_counters(const struct xt_table_info *t,
 708                          struct xt_counters counters[])
 709 {
 710         struct arpt_entry *iter;
 711         unsigned int cpu;
 712         unsigned int i;
 713         unsigned int curcpu = get_cpu();
 714
 715         /* Instead of clearing (by a previous call to memset())
 716          * the counters and using adds, we set the counters
 717          * with data used by 'current' CPU
 718          *
 719          * Bottom half has to be disabled to prevent deadlock
 720          * if new softirq were to run and call ipt_do_table
 721          */
 722         local_bh_disable();
 723         i = 0;
 724         xt_entry_foreach(iter, t->entries[curcpu], t->size) {
 725                 SET_COUNTER(counters[i], iter->counters.bcnt,
 726                             iter->counters.pcnt);
 727                 ++i;
 728         }
 729         local_bh_enable();
 730         /* Processing counters from other cpus, we can let bottom half enabled,
 731          * (preemption is disabled)
 732          */
 733
 734         for_each_possible_cpu(cpu) {
 735                 if (cpu == curcpu)
 736                         continue;
 737                 i = 0;
 738                 local_bh_disable();
 739                 xt_info_wrlock(cpu);
 740                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 741                         ADD_COUNTER(counters[i], iter->counters.bcnt,
 742                                     iter->counters.pcnt);
 743                         ++i;
 744                 }
 745                 xt_info_wrunlock(cpu);
 746                 local_bh_enable();
 747         }
 748         put_cpu();
 749 }
 750
 751 static struct xt_counters *alloc_counters(const struct xt_table *table)
 752 {
 753         unsigned int countersize;
 754         struct xt_counters *counters;
 755         const struct xt_table_info *private = table->private;
 756
 757         /* We need atomic snapshot of counters: rest doesn't change
 758          * (other than comefrom, which userspace doesn't care
 759          * about).
 760          */
 761         countersize = sizeof(struct xt_counters) * private->number;
 762         counters = vmalloc(countersize);
 763
 764         if (counters == NULL)
 765                 return ERR_PTR(-ENOMEM);
 766
 767         get_counters(private, counters);
 768
 769         return counters;
 770 }
 771
 772 static int copy_entries_to_user(unsigned int total_size,
 773                                 const struct xt_table *table,
 774                                 void __user *userptr)
 775 {
 776         unsigned int off, num;
 777         const struct arpt_entry *e;
 778         struct xt_counters *counters;
 779         struct xt_table_info *private = table->private;
 780         int ret = 0;
 781         void *loc_cpu_entry;
 782
 783         counters = alloc_counters(table);
 784         if (IS_ERR(counters))
 785                 return PTR_ERR(counters);
 786
 787         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 788         /* ... then copy entire thing ... */
 789         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 790                 ret = -EFAULT;
 791                 goto free_counters;
 792         }
 793
 794         /* FIXME: use iterator macros --RR */
 795         /* ... then go back and fix counters and names */
 796         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 797                 const struct arpt_entry_target *t;
 798
 799                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 800                 if (copy_to_user(userptr + off
 801                                  + offsetof(struct arpt_entry, counters),
 802                                  &counters[num],
 803                                  sizeof(counters[num])) != 0) {
 804                         ret = -EFAULT;
 805                         goto free_counters;
 806                 }
 807
 808                 t = arpt_get_target_c(e);
 809                 if (copy_to_user(userptr + off + e->target_offset
 810                                  + offsetof(struct arpt_entry_target,
 811                                             u.user.name),
 812                                  t->u.kernel.target->name,
 813                                  strlen(t->u.kernel.target->name)+1) != 0) {
 814                         ret = -EFAULT;
 815                         goto free_counters;
 816                 }
 817         }
 818
 819  free_counters:
 820         vfree(counters);
 821         return ret;
 822 }
 823
 824 #ifdef CONFIG_COMPAT
 825 static void compat_standard_from_user(void *dst, const void *src)
 826 {
 827         int v = *(compat_int_t *)src;
 828
 829         if (v > 0)
 830                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 831         memcpy(dst, &v, sizeof(v));
 832 }
 833
 834 static int compat_standard_to_user(void __user *dst, const void *src)
 835 {
 836         compat_int_t cv = *(int *)src;
 837
 838         if (cv > 0)
 839                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 840         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 841 }
 842
 843 static int compat_calc_entry(const struct arpt_entry *e,
 844                              const struct xt_table_info *info,
 845                              const void *base, struct xt_table_info *newinfo)
 846 {
 847         const struct arpt_entry_target *t;
 848         unsigned int entry_offset;
 849         int off, i, ret;
 850
 851         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 852         entry_offset = (void *)e - base;
 853
 854         t = arpt_get_target_c(e);
 855         off += xt_compat_target_offset(t->u.kernel.target);
 856         newinfo->size -= off;
 857         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 858         if (ret)
 859                 return ret;
 860
 861         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 862                 if (info->hook_entry[i] &&
 863                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 864                         newinfo->hook_entry[i] -= off;
 865                 if (info->underflow[i] &&
 866                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 867                         newinfo->underflow[i] -= off;
 868         }
 869         return 0;
 870 }
 871
 872 static int compat_table_info(const struct xt_table_info *info,
 873                              struct xt_table_info *newinfo)
 874 {
 875         struct arpt_entry *iter;
 876         void *loc_cpu_entry;
 877         int ret;
 878
 879         if (!newinfo || !info)
 880                 return -EINVAL;
 881
 882         /* we dont care about newinfo->entries[] */
 883         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 884         newinfo->initial_entries = 0;
 885         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 886         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 887                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 888                 if (ret != 0)
 889                         return ret;
 890         }
 891         return 0;
 892 }
 893 #endif
 894
 895 static int get_info(struct net *net, void __user *user,
 896                     const int *len, int compat)
 897 {
 898         char name[ARPT_TABLE_MAXNAMELEN];
 899         struct xt_table *t;
 900         int ret;
 901
 902         if (*len != sizeof(struct arpt_getinfo)) {
 903                 duprintf("length %u != %Zu\n", *len,
 904                          sizeof(struct arpt_getinfo));
 905                 return -EINVAL;
 906         }
 907
 908         if (copy_from_user(name, user, sizeof(name)) != 0)
 909                 return -EFAULT;
 910
 911         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 912 #ifdef CONFIG_COMPAT
 913         if (compat)
 914                 xt_compat_lock(NFPROTO_ARP);
 915 #endif
 916         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 917                                     "arptable_%s", name);
 918         if (t && !IS_ERR(t)) {
 919                 struct arpt_getinfo info;
 920                 const struct xt_table_info *private = t->private;
 921 #ifdef CONFIG_COMPAT
 922                 struct xt_table_info tmp;
 923
 924                 if (compat) {
 925                         ret = compat_table_info(private, &tmp);
 926                         xt_compat_flush_offsets(NFPROTO_ARP);
 927                         private = &tmp;
 928                 }
 929 #endif
 930                 info.valid_hooks = t->valid_hooks;
 931                 memcpy(info.hook_entry, private->hook_entry,
 932                        sizeof(info.hook_entry));
 933                 memcpy(info.underflow, private->underflow,
 934                        sizeof(info.underflow));
 935                 info.num_entries = private->number;
 936                 info.size = private->size;
 937                 strcpy(info.name, name);
 938
 939                 if (copy_to_user(user, &info, *len) != 0)
 940                         ret = -EFAULT;
 941                 else
 942                         ret = 0;
 943                 xt_table_unlock(t);
 944                 module_put(t->me);
 945         } else
 946                 ret = t ? PTR_ERR(t) : -ENOENT;
 947 #ifdef CONFIG_COMPAT
 948         if (compat)
 949                 xt_compat_unlock(NFPROTO_ARP);
 950 #endif
 951         return ret;
 952 }
 953
 954 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 955                        const int *len)
 956 {
 957         int ret;
 958         struct arpt_get_entries get;
 959         struct xt_table *t;
 960
 961         if (*len < sizeof(get)) {
 962                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 963                 return -EINVAL;
 964         }
 965         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 966                 return -EFAULT;
 967         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 968                 duprintf("get_entries: %u != %Zu\n", *len,
 969                          sizeof(struct arpt_get_entries) + get.size);
 970                 return -EINVAL;
 971         }
 972
 973         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 974         if (t && !IS_ERR(t)) {
 975                 const struct xt_table_info *private = t->private;
 976
 977                 duprintf("t->private->number = %u\n",
 978                          private->number);
 979                 if (get.size == private->size)
 980                         ret = copy_entries_to_user(private->size,
 981                                                    t, uptr->entrytable);
 982                 else {
 983                         duprintf("get_entries: I've got %u not %u!\n",
 984                                  private->size, get.size);
 985                         ret = -EAGAIN;
 986                 }
 987                 module_put(t->me);
 988                 xt_table_unlock(t);
 989         } else
 990                 ret = t ? PTR_ERR(t) : -ENOENT;
 991
 992         return ret;
 993 }
 994
 995 static int __do_replace(struct net *net, const char *name,
 996                         unsigned int valid_hooks,
 997                         struct xt_table_info *newinfo,
 998                         unsigned int num_counters,
 999                         void __user *counters_ptr)
1000 {
1001         int ret;
1002         struct xt_table *t;
1003         struct xt_table_info *oldinfo;
1004         struct xt_counters *counters;
1005         void *loc_cpu_old_entry;
1006         struct arpt_entry *iter;
1007
1008         ret = 0;
1009         counters = vmalloc(num_counters * sizeof(struct xt_counters));
1010         if (!counters) {
1011                 ret = -ENOMEM;
1012                 goto out;
1013         }
1014
1015         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1016                                     "arptable_%s", name);
1017         if (!t || IS_ERR(t)) {
1018                 ret = t ? PTR_ERR(t) : -ENOENT;
1019                 goto free_newinfo_counters_untrans;
1020         }
1021
1022         /* You lied! */
1023         if (valid_hooks != t->valid_hooks) {
1024                 duprintf("Valid hook crap: %08X vs %08X\n",
1025                          valid_hooks, t->valid_hooks);
1026                 ret = -EINVAL;
1027                 goto put_module;
1028         }
1029
1030         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1031         if (!oldinfo)
1032                 goto put_module;
1033
1034         /* Update module usage count based on number of rules */
1035         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1036                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1037         if ((oldinfo->number > oldinfo->initial_entries) ||
1038             (newinfo->number <= oldinfo->initial_entries))
1039                 module_put(t->me);
1040         if ((oldinfo->number > oldinfo->initial_entries) &&
1041             (newinfo->number <= oldinfo->initial_entries))
1042                 module_put(t->me);
1043
1044         /* Get the old counters, and synchronize with replace */
1045         get_counters(oldinfo, counters);
1046
1047         /* Decrease module usage counts and free resource */
1048         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1049         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1050                 cleanup_entry(iter);
1051
1052         xt_free_table_info(oldinfo);
1053         if (copy_to_user(counters_ptr, counters,
1054                          sizeof(struct xt_counters) * num_counters) != 0)
1055                 ret = -EFAULT;
1056         vfree(counters);
1057         xt_table_unlock(t);
1058         return ret;
1059
1060  put_module:
1061         module_put(t->me);
1062         xt_table_unlock(t);
1063  free_newinfo_counters_untrans:
1064         vfree(counters);
1065  out:
1066         return ret;
1067 }
1068
1069 static int do_replace(struct net *net, const void __user *user,
1070                       unsigned int len)
1071 {
1072         int ret;
1073         struct arpt_replace tmp;
1074         struct xt_table_info *newinfo;
1075         void *loc_cpu_entry;
1076         struct arpt_entry *iter;
1077
1078         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1079                 return -EFAULT;
1080
1081         /* overflow check */
1082         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1083                 return -ENOMEM;
1084
1085         newinfo = xt_alloc_table_info(tmp.size);
1086         if (!newinfo)
1087                 return -ENOMEM;
1088
1089         /* choose the copy that is on our node/cpu */
1090         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1091         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1092                            tmp.size) != 0) {
1093                 ret = -EFAULT;
1094                 goto free_newinfo;
1095         }
1096
1097         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1098         if (ret != 0)
1099                 goto free_newinfo;
1100
1101         duprintf("arp_tables: Translated table\n");
1102
1103         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1104                            tmp.num_counters, tmp.counters);
1105         if (ret)
1106                 goto free_newinfo_untrans;
1107         return 0;
1108
1109  free_newinfo_untrans:
1110         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1111                 cleanup_entry(iter);
1112  free_newinfo:
1113         xt_free_table_info(newinfo);
1114         return ret;
1115 }
1116
1117 static int do_add_counters(struct net *net, const void __user *user,
1118                            unsigned int len, int compat)
1119 {
1120         unsigned int i, curcpu;
1121         struct xt_counters_info tmp;
1122         struct xt_counters *paddc;
1123         unsigned int num_counters;
1124         const char *name;
1125         int size;
1126         void *ptmp;
1127         struct xt_table *t;
1128         const struct xt_table_info *private;
1129         int ret = 0;
1130         void *loc_cpu_entry;
1131         struct arpt_entry *iter;
1132 #ifdef CONFIG_COMPAT
1133         struct compat_xt_counters_info compat_tmp;
1134
1135         if (compat) {
1136                 ptmp = &compat_tmp;
1137                 size = sizeof(struct compat_xt_counters_info);
1138         } else
1139 #endif
1140         {
1141                 ptmp = &tmp;
1142                 size = sizeof(struct xt_counters_info);
1143         }
1144
1145         if (copy_from_user(ptmp, user, size) != 0)
1146                 return -EFAULT;
1147
1148 #ifdef CONFIG_COMPAT
1149         if (compat) {
1150                 num_counters = compat_tmp.num_counters;
1151                 name = compat_tmp.name;
1152         } else
1153 #endif
1154         {
1155                 num_counters = tmp.num_counters;
1156                 name = tmp.name;
1157         }
1158
1159         if (len != size + num_counters * sizeof(struct xt_counters))
1160                 return -EINVAL;
1161
1162         paddc = vmalloc(len - size);
1163         if (!paddc)
1164                 return -ENOMEM;
1165
1166         if (copy_from_user(paddc, user + size, len - size) != 0) {
1167                 ret = -EFAULT;
1168                 goto free;
1169         }
1170
1171         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1172         if (!t || IS_ERR(t)) {
1173                 ret = t ? PTR_ERR(t) : -ENOENT;
1174                 goto free;
1175         }
1176
1177         local_bh_disable();
1178         private = t->private;
1179         if (private->number != num_counters) {
1180                 ret = -EINVAL;
1181                 goto unlock_up_free;
1182         }
1183
1184         i = 0;
1185         /* Choose the copy that is on our node */
1186         curcpu = smp_processor_id();
1187         loc_cpu_entry = private->entries[curcpu];
1188         xt_info_wrlock(curcpu);
1189         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1190                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1191                 ++i;
1192         }
1193         xt_info_wrunlock(curcpu);
1194  unlock_up_free:
1195         local_bh_enable();
1196         xt_table_unlock(t);
1197         module_put(t->me);
1198  free:
1199         vfree(paddc);
1200
1201         return ret;
1202 }
1203
1204 #ifdef CONFIG_COMPAT
1205 static inline void compat_release_entry(struct compat_arpt_entry *e)
1206 {
1207         struct arpt_entry_target *t;
1208
1209         t = compat_arpt_get_target(e);
1210         module_put(t->u.kernel.target->me);
1211 }
1212
1213 static inline int
1214 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1215                                   struct xt_table_info *newinfo,
1216                                   unsigned int *size,
1217                                   const unsigned char *base,
1218                                   const unsigned char *limit,
1219                                   const unsigned int *hook_entries,
1220                                   const unsigned int *underflows,
1221                                   const char *name)
1222 {
1223         struct arpt_entry_target *t;
1224         struct xt_target *target;
1225         unsigned int entry_offset;
1226         int ret, off, h;
1227
1228         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1229         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1230             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1231                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1232                 return -EINVAL;
1233         }
1234
1235         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1236                              sizeof(struct compat_xt_entry_target)) {
1237                 duprintf("checking: element %p size %u\n",
1238                          e, e->next_offset);
1239                 return -EINVAL;
1240         }
1241
1242         /* For purposes of check_entry casting the compat entry is fine */
1243         ret = check_entry((struct arpt_entry *)e, name);
1244         if (ret)
1245                 return ret;
1246
1247         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1248         entry_offset = (void *)e - (void *)base;
1249
1250         t = compat_arpt_get_target(e);
1251         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1252                                         t->u.user.revision);
1253         if (IS_ERR(target)) {
1254                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1255                          t->u.user.name);
1256                 ret = PTR_ERR(target);
1257                 goto out;
1258         }
1259         t->u.kernel.target = target;
1260
1261         off += xt_compat_target_offset(target);
1262         *size += off;
1263         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1264         if (ret)
1265                 goto release_target;
1266
1267         /* Check hooks & underflows */
1268         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1269                 if ((unsigned char *)e - base == hook_entries[h])
1270                         newinfo->hook_entry[h] = hook_entries[h];
1271                 if ((unsigned char *)e - base == underflows[h])
1272                         newinfo->underflow[h] = underflows[h];
1273         }
1274
1275         /* Clear counters and comefrom */
1276         memset(&e->counters, 0, sizeof(e->counters));
1277         e->comefrom = 0;
1278         return 0;
1279
1280 release_target:
1281         module_put(t->u.kernel.target->me);
1282 out:
1283         return ret;
1284 }
1285
1286 static int
1287 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1288                             unsigned int *size, const char *name,
1289                             struct xt_table_info *newinfo, unsigned char *base)
1290 {
1291         struct arpt_entry_target *t;
1292         struct xt_target *target;
1293         struct arpt_entry *de;
1294         unsigned int origsize;
1295         int ret, h;
1296
1297         ret = 0;
1298         origsize = *size;
1299         de = (struct arpt_entry *)*dstptr;
1300         memcpy(de, e, sizeof(struct arpt_entry));
1301         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1302
1303         *dstptr += sizeof(struct arpt_entry);
1304         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1305
1306         de->target_offset = e->target_offset - (origsize - *size);
1307         t = compat_arpt_get_target(e);
1308         target = t->u.kernel.target;
1309         xt_compat_target_from_user(t, dstptr, size);
1310
1311         de->next_offset = e->next_offset - (origsize - *size);
1312         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1313                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1314                         newinfo->hook_entry[h] -= origsize - *size;
1315                 if ((unsigned char *)de - base < newinfo->underflow[h])
1316                         newinfo->underflow[h] -= origsize - *size;
1317         }
1318         return ret;
1319 }
1320
1321 static int translate_compat_table(const char *name,
1322                                   unsigned int valid_hooks,
1323                                   struct xt_table_info **pinfo,
1324                                   void **pentry0,
1325                                   unsigned int total_size,
1326                                   unsigned int number,
1327                                   unsigned int *hook_entries,
1328                                   unsigned int *underflows)
1329 {
1330         unsigned int i, j;
1331         struct xt_table_info *newinfo, *info;
1332         void *pos, *entry0, *entry1;
1333         struct compat_arpt_entry *iter0;
1334         struct arpt_entry *iter1;
1335         unsigned int size;
1336         int ret = 0;
1337
1338         info = *pinfo;
1339         entry0 = *pentry0;
1340         size = total_size;
1341         info->number = number;
1342
1343         /* Init all hooks to impossible value. */
1344         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1345                 info->hook_entry[i] = 0xFFFFFFFF;
1346                 info->underflow[i] = 0xFFFFFFFF;
1347         }
1348
1349         duprintf("translate_compat_table: size %u\n", info->size);
1350         j = 0;
1351         xt_compat_lock(NFPROTO_ARP);
1352         /* Walk through entries, checking offsets. */
1353         xt_entry_foreach(iter0, entry0, total_size) {
1354                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1355                                                         entry0,
1356                                                         entry0 + total_size,
1357                                                         hook_entries,
1358                                                         underflows,
1359                                                         name);
1360                 if (ret != 0)
1361                         goto out_unlock;
1362                 ++j;
1363         }
1364
1365         ret = -EINVAL;
1366         if (j != number) {
1367                 duprintf("translate_compat_table: %u not %u entries\n",
1368                          j, number);
1369                 goto out_unlock;
1370         }
1371
1372         /* Check hooks all assigned */
1373         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1374                 /* Only hooks which are valid */
1375                 if (!(valid_hooks & (1 << i)))
1376                         continue;
1377                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1378                         duprintf("Invalid hook entry %u %u\n",
1379                                  i, hook_entries[i]);
1380                         goto out_unlock;
1381                 }
1382                 if (info->underflow[i] == 0xFFFFFFFF) {
1383                         duprintf("Invalid underflow %u %u\n",
1384                                  i, underflows[i]);
1385                         goto out_unlock;
1386                 }
1387         }
1388
1389         ret = -ENOMEM;
1390         newinfo = xt_alloc_table_info(size);
1391         if (!newinfo)
1392                 goto out_unlock;
1393
1394         newinfo->number = number;
1395         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1396                 newinfo->hook_entry[i] = info->hook_entry[i];
1397                 newinfo->underflow[i] = info->underflow[i];
1398         }
1399         entry1 = newinfo->entries[raw_smp_processor_id()];
1400         pos = entry1;
1401         size = total_size;
1402         xt_entry_foreach(iter0, entry0, total_size) {
1403                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1404                                                   name, newinfo, entry1);
1405                 if (ret != 0)
1406                         break;
1407         }
1408         xt_compat_flush_offsets(NFPROTO_ARP);
1409         xt_compat_unlock(NFPROTO_ARP);
1410         if (ret)
1411                 goto free_newinfo;
1412
1413         ret = -ELOOP;
1414         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1415                 goto free_newinfo;
1416
1417         i = 0;
1418         xt_entry_foreach(iter1, entry1, newinfo->size) {
1419                 ret = check_target(iter1, name);
1420                 if (ret != 0)
1421                         break;
1422                 ++i;
1423                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1424                     XT_ERROR_TARGET) == 0)
1425                         ++newinfo->stacksize;
1426         }
1427         if (ret) {
1428                 /*
1429                  * The first i matches need cleanup_entry (calls ->destroy)
1430                  * because they had called ->check already. The other j-i
1431                  * entries need only release.
1432                  */
1433                 int skip = i;
1434                 j -= i;
1435                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1436                         if (skip-- > 0)
1437                                 continue;
1438                         if (j-- == 0)
1439                                 break;
1440                         compat_release_entry(iter0);
1441                 }
1442                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1443                         if (i-- == 0)
1444                                 break;
1445                         cleanup_entry(iter1);
1446                 }
1447                 xt_free_table_info(newinfo);
1448                 return ret;
1449         }
1450
1451         /* And one copy for every other CPU */
1452         for_each_possible_cpu(i)
1453                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1454                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1455
1456         *pinfo = newinfo;
1457         *pentry0 = entry1;
1458         xt_free_table_info(info);
1459         return 0;
1460
1461 free_newinfo:
1462         xt_free_table_info(newinfo);
1463 out:
1464         xt_entry_foreach(iter0, entry0, total_size) {
1465                 if (j-- == 0)
1466                         break;
1467                 compat_release_entry(iter0);
1468         }
1469         return ret;
1470 out_unlock:
1471         xt_compat_flush_offsets(NFPROTO_ARP);
1472         xt_compat_unlock(NFPROTO_ARP);
1473         goto out;
1474 }
1475
1476 struct compat_arpt_replace {
1477         char                            name[ARPT_TABLE_MAXNAMELEN];
1478         u32                             valid_hooks;
1479         u32                             num_entries;
1480         u32                             size;
1481         u32                             hook_entry[NF_ARP_NUMHOOKS];
1482         u32                             underflow[NF_ARP_NUMHOOKS];
1483         u32                             num_counters;
1484         compat_uptr_t                   counters;
1485         struct compat_arpt_entry        entries[0];
1486 };
1487
1488 static int compat_do_replace(struct net *net, void __user *user,
1489                              unsigned int len)
1490 {
1491         int ret;
1492         struct compat_arpt_replace tmp;
1493         struct xt_table_info *newinfo;
1494         void *loc_cpu_entry;
1495         struct arpt_entry *iter;
1496
1497         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1498                 return -EFAULT;
1499
1500         /* overflow check */
1501         if (tmp.size >= INT_MAX / num_possible_cpus())
1502                 return -ENOMEM;
1503         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1504                 return -ENOMEM;
1505
1506         newinfo = xt_alloc_table_info(tmp.size);
1507         if (!newinfo)
1508                 return -ENOMEM;
1509
1510         /* choose the copy that is on our node/cpu */
1511         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1512         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1513                 ret = -EFAULT;
1514                 goto free_newinfo;
1515         }
1516
1517         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1518                                      &newinfo, &loc_cpu_entry, tmp.size,
1519                                      tmp.num_entries, tmp.hook_entry,
1520                                      tmp.underflow);
1521         if (ret != 0)
1522                 goto free_newinfo;
1523
1524         duprintf("compat_do_replace: Translated table\n");
1525
1526         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1527                            tmp.num_counters, compat_ptr(tmp.counters));
1528         if (ret)
1529                 goto free_newinfo_untrans;
1530         return 0;
1531
1532  free_newinfo_untrans:
1533         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1534                 cleanup_entry(iter);
1535  free_newinfo:
1536         xt_free_table_info(newinfo);
1537         return ret;
1538 }
1539
1540 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1541                                   unsigned int len)
1542 {
1543         int ret;
1544
1545         if (!capable(CAP_NET_ADMIN))
1546                 return -EPERM;
1547
1548         switch (cmd) {
1549         case ARPT_SO_SET_REPLACE:
1550                 ret = compat_do_replace(sock_net(sk), user, len);
1551                 break;
1552
1553         case ARPT_SO_SET_ADD_COUNTERS:
1554                 ret = do_add_counters(sock_net(sk), user, len, 1);
1555                 break;
1556
1557         default:
1558                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1559                 ret = -EINVAL;
1560         }
1561
1562         return ret;
1563 }
1564
1565 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1566                                      compat_uint_t *size,
1567                                      struct xt_counters *counters,
1568                                      unsigned int i)
1569 {
1570         struct arpt_entry_target *t;
1571         struct compat_arpt_entry __user *ce;
1572         u_int16_t target_offset, next_offset;
1573         compat_uint_t origsize;
1574         int ret;
1575
1576         origsize = *size;
1577         ce = (struct compat_arpt_entry __user *)*dstptr;
1578         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1579             copy_to_user(&ce->counters, &counters[i],
1580             sizeof(counters[i])) != 0)
1581                 return -EFAULT;
1582
1583         *dstptr += sizeof(struct compat_arpt_entry);
1584         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1585
1586         target_offset = e->target_offset - (origsize - *size);
1587
1588         t = arpt_get_target(e);
1589         ret = xt_compat_target_to_user(t, dstptr, size);
1590         if (ret)
1591                 return ret;
1592         next_offset = e->next_offset - (origsize - *size);
1593         if (put_user(target_offset, &ce->target_offset) != 0 ||
1594             put_user(next_offset, &ce->next_offset) != 0)
1595                 return -EFAULT;
1596         return 0;
1597 }
1598
1599 static int compat_copy_entries_to_user(unsigned int total_size,
1600                                        struct xt_table *table,
1601                                        void __user *userptr)
1602 {
1603         struct xt_counters *counters;
1604         const struct xt_table_info *private = table->private;
1605         void __user *pos;
1606         unsigned int size;
1607         int ret = 0;
1608         void *loc_cpu_entry;
1609         unsigned int i = 0;
1610         struct arpt_entry *iter;
1611
1612         counters = alloc_counters(table);
1613         if (IS_ERR(counters))
1614                 return PTR_ERR(counters);
1615
1616         /* choose the copy on our node/cpu */
1617         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1618         pos = userptr;
1619         size = total_size;
1620         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1621                 ret = compat_copy_entry_to_user(iter, &pos,
1622                                                 &size, counters, i++);
1623                 if (ret != 0)
1624                         break;
1625         }
1626         vfree(counters);
1627         return ret;
1628 }
1629
1630 struct compat_arpt_get_entries {
1631         char name[ARPT_TABLE_MAXNAMELEN];
1632         compat_uint_t size;
1633         struct compat_arpt_entry entrytable[0];
1634 };
1635
1636 static int compat_get_entries(struct net *net,
1637                               struct compat_arpt_get_entries __user *uptr,
1638                               int *len)
1639 {
1640         int ret;
1641         struct compat_arpt_get_entries get;
1642         struct xt_table *t;
1643
1644         if (*len < sizeof(get)) {
1645                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1646                 return -EINVAL;
1647         }
1648         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1649                 return -EFAULT;
1650         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1651                 duprintf("compat_get_entries: %u != %zu\n",
1652                          *len, sizeof(get) + get.size);
1653                 return -EINVAL;
1654         }
1655
1656         xt_compat_lock(NFPROTO_ARP);
1657         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1658         if (t && !IS_ERR(t)) {
1659                 const struct xt_table_info *private = t->private;
1660                 struct xt_table_info info;
1661
1662                 duprintf("t->private->number = %u\n", private->number);
1663                 ret = compat_table_info(private, &info);
1664                 if (!ret && get.size == info.size) {
1665                         ret = compat_copy_entries_to_user(private->size,
1666                                                           t, uptr->entrytable);
1667                 } else if (!ret) {
1668                         duprintf("compat_get_entries: I've got %u not %u!\n",
1669                                  private->size, get.size);
1670                         ret = -EAGAIN;
1671                 }
1672                 xt_compat_flush_offsets(NFPROTO_ARP);
1673                 module_put(t->me);
1674                 xt_table_unlock(t);
1675         } else
1676                 ret = t ? PTR_ERR(t) : -ENOENT;
1677
1678         xt_compat_unlock(NFPROTO_ARP);
1679         return ret;
1680 }
1681
1682 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1683
1684 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1685                                   int *len)
1686 {
1687         int ret;
1688
1689         if (!capable(CAP_NET_ADMIN))
1690                 return -EPERM;
1691
1692         switch (cmd) {
1693         case ARPT_SO_GET_INFO:
1694                 ret = get_info(sock_net(sk), user, len, 1);
1695                 break;
1696         case ARPT_SO_GET_ENTRIES:
1697                 ret = compat_get_entries(sock_net(sk), user, len);
1698                 break;
1699         default:
1700                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1701         }
1702         return ret;
1703 }
1704 #endif
1705
1706 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1707 {
1708         int ret;
1709
1710         if (!capable(CAP_NET_ADMIN))
1711                 return -EPERM;
1712
1713         switch (cmd) {
1714         case ARPT_SO_SET_REPLACE:
1715                 ret = do_replace(sock_net(sk), user, len);
1716                 break;
1717
1718         case ARPT_SO_SET_ADD_COUNTERS:
1719                 ret = do_add_counters(sock_net(sk), user, len, 0);
1720                 break;
1721
1722         default:
1723                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1724                 ret = -EINVAL;
1725         }
1726
1727         return ret;
1728 }
1729
1730 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1731 {
1732         int ret;
1733
1734         if (!capable(CAP_NET_ADMIN))
1735                 return -EPERM;
1736
1737         switch (cmd) {
1738         case ARPT_SO_GET_INFO:
1739                 ret = get_info(sock_net(sk), user, len, 0);
1740                 break;
1741
1742         case ARPT_SO_GET_ENTRIES:
1743                 ret = get_entries(sock_net(sk), user, len);
1744                 break;
1745
1746         case ARPT_SO_GET_REVISION_TARGET: {
1747                 struct xt_get_revision rev;
1748
1749                 if (*len != sizeof(rev)) {
1750                         ret = -EINVAL;
1751                         break;
1752                 }
1753                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1754                         ret = -EFAULT;
1755                         break;
1756                 }
1757
1758                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1759                                                          rev.revision, 1, &ret),
1760                                         "arpt_%s", rev.name);
1761                 break;
1762         }
1763
1764         default:
1765                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1766                 ret = -EINVAL;
1767         }
1768
1769         return ret;
1770 }
1771
1772 struct xt_table *arpt_register_table(struct net *net,
1773                                      const struct xt_table *table,
1774                                      const struct arpt_replace *repl)
1775 {
1776         int ret;
1777         struct xt_table_info *newinfo;
1778         struct xt_table_info bootstrap = {0};
1779         void *loc_cpu_entry;
1780         struct xt_table *new_table;
1781
1782         newinfo = xt_alloc_table_info(repl->size);
1783         if (!newinfo) {
1784                 ret = -ENOMEM;
1785                 goto out;
1786         }
1787
1788         /* choose the copy on our node/cpu */
1789         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1790         memcpy(loc_cpu_entry, repl->entries, repl->size);
1791
1792         ret = translate_table(newinfo, loc_cpu_entry, repl);
1793         duprintf("arpt_register_table: translate table gives %d\n", ret);
1794         if (ret != 0)
1795                 goto out_free;
1796
1797         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1798         if (IS_ERR(new_table)) {
1799                 ret = PTR_ERR(new_table);
1800                 goto out_free;
1801         }
1802         return new_table;
1803
1804 out_free:
1805         xt_free_table_info(newinfo);
1806 out:
1807         return ERR_PTR(ret);
1808 }
1809
1810 void arpt_unregister_table(struct xt_table *table)
1811 {
1812         struct xt_table_info *private;
1813         void *loc_cpu_entry;
1814         struct module *table_owner = table->me;
1815         struct arpt_entry *iter;
1816
1817         private = xt_unregister_table(table);
1818
1819         /* Decrease module usage counts and free resources */
1820         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1821         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1822                 cleanup_entry(iter);
1823         if (private->number > private->initial_entries)
1824                 module_put(table_owner);
1825         xt_free_table_info(private);
1826 }
1827
1828 /* The built-in targets: standard (NULL) and error. */
1829 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1830         {
1831                 .name             = ARPT_STANDARD_TARGET,
1832                 .targetsize       = sizeof(int),
1833                 .family           = NFPROTO_ARP,
1834 #ifdef CONFIG_COMPAT
1835                 .compatsize       = sizeof(compat_int_t),
1836                 .compat_from_user = compat_standard_from_user,
1837                 .compat_to_user   = compat_standard_to_user,
1838 #endif
1839         },
1840         {
1841                 .name             = ARPT_ERROR_TARGET,
1842                 .target           = arpt_error,
1843                 .targetsize       = ARPT_FUNCTION_MAXNAMELEN,
1844                 .family           = NFPROTO_ARP,
1845         },
1846 };
1847
1848 static struct nf_sockopt_ops arpt_sockopts = {
1849         .pf             = PF_INET,
1850         .set_optmin     = ARPT_BASE_CTL,
1851         .set_optmax     = ARPT_SO_SET_MAX+1,
1852         .set            = do_arpt_set_ctl,
1853 #ifdef CONFIG_COMPAT
1854         .compat_set     = compat_do_arpt_set_ctl,
1855 #endif
1856         .get_optmin     = ARPT_BASE_CTL,
1857         .get_optmax     = ARPT_SO_GET_MAX+1,
1858         .get            = do_arpt_get_ctl,
1859 #ifdef CONFIG_COMPAT
1860         .compat_get     = compat_do_arpt_get_ctl,
1861 #endif
1862         .owner          = THIS_MODULE,
1863 };
1864
1865 static int __net_init arp_tables_net_init(struct net *net)
1866 {
1867         return xt_proto_init(net, NFPROTO_ARP);
1868 }
1869
1870 static void __net_exit arp_tables_net_exit(struct net *net)
1871 {
1872         xt_proto_fini(net, NFPROTO_ARP);
1873 }
1874
1875 static struct pernet_operations arp_tables_net_ops = {
1876         .init = arp_tables_net_init,
1877         .exit = arp_tables_net_exit,
1878 };
1879
1880 static int __init arp_tables_init(void)
1881 {
1882         int ret;
1883
1884         ret = register_pernet_subsys(&arp_tables_net_ops);
1885         if (ret < 0)
1886                 goto err1;
1887
1888         /* Noone else will be downing sem now, so we won't sleep */
1889         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1890         if (ret < 0)
1891                 goto err2;
1892
1893         /* Register setsockopt */
1894         ret = nf_register_sockopt(&arpt_sockopts);
1895         if (ret < 0)
1896                 goto err4;
1897
1898         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1899         return 0;
1900
1901 err4:
1902         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1903 err2:
1904         unregister_pernet_subsys(&arp_tables_net_ops);
1905 err1:
1906         return ret;
1907 }
1908
1909 static void __exit arp_tables_fini(void)
1910 {
1911         nf_unregister_sockopt(&arpt_sockopts);
1912         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1913         unregister_pernet_subsys(&arp_tables_net_ops);
1914 }
1915
1916 EXPORT_SYMBOL(arpt_register_table);
1917 EXPORT_SYMBOL(arpt_unregister_table);
1918 EXPORT_SYMBOL(arpt_do_table);
1919
1920 module_init(arp_tables_init);
1921 module_exit(arp_tables_fini);