kernel/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  * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
  10  *
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13 #include <linux/kernel.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/capability.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/kmod.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/mutex.h>
  24 #include <linux/err.h>
  25 #include <net/compat.h>
  26 #include <net/sock.h>
  27 #include <asm/uaccess.h>
  28
  29 #include <linux/netfilter/x_tables.h>
  30 #include <linux/netfilter_arp/arp_tables.h>
  31 #include "../../netfilter/xt_repldata.h"
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  35 MODULE_DESCRIPTION("arptables core");
  36
  37 /*#define DEBUG_ARP_TABLES*/
  38 /*#define DEBUG_ARP_TABLES_USER*/
  39
  40 #ifdef DEBUG_ARP_TABLES
  41 #define dprintf(format, args...)  printk(format , ## args)
  42 #else
  43 #define dprintf(format, args...)
  44 #endif
  45
  46 #ifdef DEBUG_ARP_TABLES_USER
  47 #define duprintf(format, args...) printk(format , ## args)
  48 #else
  49 #define duprintf(format, args...)
  50 #endif
  51
  52 #ifdef CONFIG_NETFILTER_DEBUG
  53 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  54 #else
  55 #define ARP_NF_ASSERT(x)
  56 #endif
  57
  58 void *arpt_alloc_initial_table(const struct xt_table *info)
  59 {
  60         return xt_alloc_initial_table(arpt, ARPT);
  61 }
  62 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  63
  64 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  65                                       const char *hdr_addr, int len)
  66 {
  67         int i, ret;
  68
  69         if (len > ARPT_DEV_ADDR_LEN_MAX)
  70                 len = ARPT_DEV_ADDR_LEN_MAX;
  71
  72         ret = 0;
  73         for (i = 0; i < len; i++)
  74                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  75
  76         return ret != 0;
  77 }
  78
  79 /*
  80  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  81  * Some arches dont care, unrolling the loop is a win on them.
  82  * For other arches, we only have a 16bit alignement.
  83  */
  84 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  85 {
  86 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  87         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  88 #else
  89         unsigned long ret = 0;
  90         const u16 *a = (const u16 *)_a;
  91         const u16 *b = (const u16 *)_b;
  92         const u16 *mask = (const u16 *)_mask;
  93         int i;
  94
  95         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  96                 ret |= (a[i] ^ b[i]) & mask[i];
  97 #endif
  98         return ret;
  99 }
 100
 101 /* Returns whether packet matches rule or not. */
 102 static inline int arp_packet_match(const struct arphdr *arphdr,
 103                                    struct net_device *dev,
 104                                    const char *indev,
 105                                    const char *outdev,
 106                                    const struct arpt_arp *arpinfo)
 107 {
 108         const char *arpptr = (char *)(arphdr + 1);
 109         const char *src_devaddr, *tgt_devaddr;
 110         __be32 src_ipaddr, tgt_ipaddr;
 111         long ret;
 112
 113 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 114
 115         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 116                   ARPT_INV_ARPOP)) {
 117                 dprintf("ARP operation field mismatch.\n");
 118                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 119                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 120                 return 0;
 121         }
 122
 123         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 124                   ARPT_INV_ARPHRD)) {
 125                 dprintf("ARP hardware address format mismatch.\n");
 126                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 127                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 128                 return 0;
 129         }
 130
 131         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 132                   ARPT_INV_ARPPRO)) {
 133                 dprintf("ARP protocol address format mismatch.\n");
 134                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 135                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 136                 return 0;
 137         }
 138
 139         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 140                   ARPT_INV_ARPHLN)) {
 141                 dprintf("ARP hardware address length mismatch.\n");
 142                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 143                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 144                 return 0;
 145         }
 146
 147         src_devaddr = arpptr;
 148         arpptr += dev->addr_len;
 149         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 150         arpptr += sizeof(u32);
 151         tgt_devaddr = arpptr;
 152         arpptr += dev->addr_len;
 153         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 154
 155         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 156                   ARPT_INV_SRCDEVADDR) ||
 157             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 158                   ARPT_INV_TGTDEVADDR)) {
 159                 dprintf("Source or target device address mismatch.\n");
 160
 161                 return 0;
 162         }
 163
 164         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 165                   ARPT_INV_SRCIP) ||
 166             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 167                   ARPT_INV_TGTIP)) {
 168                 dprintf("Source or target IP address mismatch.\n");
 169
 170                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 171                         &src_ipaddr,
 172                         &arpinfo->smsk.s_addr,
 173                         &arpinfo->src.s_addr,
 174                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 175                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 176                         &tgt_ipaddr,
 177                         &arpinfo->tmsk.s_addr,
 178                         &arpinfo->tgt.s_addr,
 179                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 180                 return 0;
 181         }
 182
 183         /* Look for ifname matches.  */
 184         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 185
 186         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 187                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 188                         indev, arpinfo->iniface,
 189                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 190                 return 0;
 191         }
 192
 193         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 194
 195         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 196                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 197                         outdev, arpinfo->outiface,
 198                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 199                 return 0;
 200         }
 201
 202         return 1;
 203 #undef FWINV
 204 }
 205
 206 static inline int arp_checkentry(const struct arpt_arp *arp)
 207 {
 208         if (arp->flags & ~ARPT_F_MASK) {
 209                 duprintf("Unknown flag bits set: %08X\n",
 210                          arp->flags & ~ARPT_F_MASK);
 211                 return 0;
 212         }
 213         if (arp->invflags & ~ARPT_INV_MASK) {
 214                 duprintf("Unknown invflag bits set: %08X\n",
 215                          arp->invflags & ~ARPT_INV_MASK);
 216                 return 0;
 217         }
 218
 219         return 1;
 220 }
 221
 222 static unsigned int
 223 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 224 {
 225         net_err_ratelimited("arp_tables: error: '%s'\n",
 226                             (const char *)par->targinfo);
 227
 228         return NF_DROP;
 229 }
 230
 231 static inline const struct xt_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 nf_hook_state *state,
 252                            struct xt_table *table)
 253 {
 254         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 255         unsigned int verdict = NF_DROP;
 256         const struct arphdr *arp;
 257         struct arpt_entry *e, *back;
 258         const char *indev, *outdev;
 259         void *table_base;
 260         const struct xt_table_info *private;
 261         struct xt_action_param acpar;
 262         unsigned int addend;
 263
 264         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 265                 return NF_DROP;
 266
 267         indev = state->in ? state->in->name : nulldevname;
 268         outdev = state->out ? state->out->name : nulldevname;
 269
 270         local_bh_disable();
 271         addend = xt_write_recseq_begin();
 272         private = table->private;
 273         /*
 274          * Ensure we load private-> members after we've fetched the base
 275          * pointer.
 276          */
 277         smp_read_barrier_depends();
 278         table_base = private->entries[smp_processor_id()];
 279
 280         e = get_entry(table_base, private->hook_entry[hook]);
 281         back = get_entry(table_base, private->underflow[hook]);
 282
 283         acpar.in      = state->in;
 284         acpar.out     = state->out;
 285         acpar.hooknum = hook;
 286         acpar.family  = NFPROTO_ARP;
 287         acpar.hotdrop = false;
 288
 289         arp = arp_hdr(skb);
 290         do {
 291                 const struct xt_entry_target *t;
 292
 293                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 294                         e = arpt_next_entry(e);
 295                         continue;
 296                 }
 297
 298                 ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
 299
 300                 t = arpt_get_target_c(e);
 301
 302                 /* Standard target? */
 303                 if (!t->u.kernel.target->target) {
 304                         int v;
 305
 306                         v = ((struct xt_standard_target *)t)->verdict;
 307                         if (v < 0) {
 308                                 /* Pop from stack? */
 309                                 if (v != XT_RETURN) {
 310                                         verdict = (unsigned int)(-v) - 1;
 311                                         break;
 312                                 }
 313                                 e = back;
 314                                 back = get_entry(table_base, back->comefrom);
 315                                 continue;
 316                         }
 317                         if (table_base + v
 318                             != arpt_next_entry(e)) {
 319                                 /* Save old back ptr in next entry */
 320                                 struct arpt_entry *next = arpt_next_entry(e);
 321                                 next->comefrom = (void *)back - table_base;
 322
 323                                 /* set back pointer to next entry */
 324                                 back = next;
 325                         }
 326
 327                         e = get_entry(table_base, v);
 328                         continue;
 329                 }
 330
 331                 /* Targets which reenter must return
 332                  * abs. verdicts
 333                  */
 334                 acpar.target   = t->u.kernel.target;
 335                 acpar.targinfo = t->data;
 336                 verdict = t->u.kernel.target->target(skb, &acpar);
 337
 338                 /* Target might have changed stuff. */
 339                 arp = arp_hdr(skb);
 340
 341                 if (verdict == XT_CONTINUE)
 342                         e = arpt_next_entry(e);
 343                 else
 344                         /* Verdict */
 345                         break;
 346         } while (!acpar.hotdrop);
 347         xt_write_recseq_end(addend);
 348         local_bh_enable();
 349
 350         if (acpar.hotdrop)
 351                 return NF_DROP;
 352         else
 353                 return verdict;
 354 }
 355
 356 /* All zeroes == unconditional rule. */
 357 static inline bool unconditional(const struct arpt_arp *arp)
 358 {
 359         static const struct arpt_arp uncond;
 360
 361         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 362 }
 363
 364 /* Figures out from what hook each rule can be called: returns 0 if
 365  * there are loops.  Puts hook bitmask in comefrom.
 366  */
 367 static int mark_source_chains(const struct xt_table_info *newinfo,
 368                               unsigned int valid_hooks, void *entry0)
 369 {
 370         unsigned int hook;
 371
 372         /* No recursion; use packet counter to save back ptrs (reset
 373          * to 0 as we leave), and comefrom to save source hook bitmask.
 374          */
 375         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 376                 unsigned int pos = newinfo->hook_entry[hook];
 377                 struct arpt_entry *e
 378                         = (struct arpt_entry *)(entry0 + pos);
 379
 380                 if (!(valid_hooks & (1 << hook)))
 381                         continue;
 382
 383                 /* Set initial back pointer. */
 384                 e->counters.pcnt = pos;
 385
 386                 for (;;) {
 387                         const struct xt_standard_target *t
 388                                 = (void *)arpt_get_target_c(e);
 389                         int visited = e->comefrom & (1 << hook);
 390
 391                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 392                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 393                                        hook, pos, e->comefrom);
 394                                 return 0;
 395                         }
 396                         e->comefrom
 397                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 398
 399                         /* Unconditional return/END. */
 400                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 401                              (strcmp(t->target.u.user.name,
 402                                      XT_STANDARD_TARGET) == 0) &&
 403                              t->verdict < 0 && unconditional(&e->arp)) ||
 404                             visited) {
 405                                 unsigned int oldpos, size;
 406
 407                                 if ((strcmp(t->target.u.user.name,
 408                                             XT_STANDARD_TARGET) == 0) &&
 409                                     t->verdict < -NF_MAX_VERDICT - 1) {
 410                                         duprintf("mark_source_chains: bad "
 411                                                 "negative verdict (%i)\n",
 412                                                                 t->verdict);
 413                                         return 0;
 414                                 }
 415
 416                                 /* Return: backtrack through the last
 417                                  * big jump.
 418                                  */
 419                                 do {
 420                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 421                                         oldpos = pos;
 422                                         pos = e->counters.pcnt;
 423                                         e->counters.pcnt = 0;
 424
 425                                         /* We're at the start. */
 426                                         if (pos == oldpos)
 427                                                 goto next;
 428
 429                                         e = (struct arpt_entry *)
 430                                                 (entry0 + pos);
 431                                 } while (oldpos == pos + e->next_offset);
 432
 433                                 /* Move along one */
 434                                 size = e->next_offset;
 435                                 e = (struct arpt_entry *)
 436                                         (entry0 + pos + size);
 437                                 e->counters.pcnt = pos;
 438                                 pos += size;
 439                         } else {
 440                                 int newpos = t->verdict;
 441
 442                                 if (strcmp(t->target.u.user.name,
 443                                            XT_STANDARD_TARGET) == 0 &&
 444                                     newpos >= 0) {
 445                                         if (newpos > newinfo->size -
 446                                                 sizeof(struct arpt_entry)) {
 447                                                 duprintf("mark_source_chains: "
 448                                                         "bad verdict (%i)\n",
 449                                                                 newpos);
 450                                                 return 0;
 451                                         }
 452
 453                                         /* This a jump; chase it. */
 454                                         duprintf("Jump rule %u -> %u\n",
 455                                                  pos, newpos);
 456                                 } else {
 457                                         /* ... this is a fallthru */
 458                                         newpos = pos + e->next_offset;
 459                                 }
 460                                 e = (struct arpt_entry *)
 461                                         (entry0 + newpos);
 462                                 e->counters.pcnt = pos;
 463                                 pos = newpos;
 464                         }
 465                 }
 466                 next:
 467                 duprintf("Finished chain %u\n", hook);
 468         }
 469         return 1;
 470 }
 471
 472 static inline int check_entry(const struct arpt_entry *e, const char *name)
 473 {
 474         const struct xt_entry_target *t;
 475
 476         if (!arp_checkentry(&e->arp)) {
 477                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 478                 return -EINVAL;
 479         }
 480
 481         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
 482                 return -EINVAL;
 483
 484         t = arpt_get_target_c(e);
 485         if (e->target_offset + t->u.target_size > e->next_offset)
 486                 return -EINVAL;
 487
 488         return 0;
 489 }
 490
 491 static inline int check_target(struct arpt_entry *e, const char *name)
 492 {
 493         struct xt_entry_target *t = arpt_get_target(e);
 494         int ret;
 495         struct xt_tgchk_param par = {
 496                 .table     = name,
 497                 .entryinfo = e,
 498                 .target    = t->u.kernel.target,
 499                 .targinfo  = t->data,
 500                 .hook_mask = e->comefrom,
 501                 .family    = NFPROTO_ARP,
 502         };
 503
 504         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 505         if (ret < 0) {
 506                 duprintf("arp_tables: check failed for `%s'.\n",
 507                          t->u.kernel.target->name);
 508                 return ret;
 509         }
 510         return 0;
 511 }
 512
 513 static inline int
 514 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 515 {
 516         struct xt_entry_target *t;
 517         struct xt_target *target;
 518         int ret;
 519
 520         ret = check_entry(e, name);
 521         if (ret)
 522                 return ret;
 523
 524         t = arpt_get_target(e);
 525         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 526                                         t->u.user.revision);
 527         if (IS_ERR(target)) {
 528                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 529                 ret = PTR_ERR(target);
 530                 goto out;
 531         }
 532         t->u.kernel.target = target;
 533
 534         ret = check_target(e, name);
 535         if (ret)
 536                 goto err;
 537         return 0;
 538 err:
 539         module_put(t->u.kernel.target->me);
 540 out:
 541         return ret;
 542 }
 543
 544 static bool check_underflow(const struct arpt_entry *e)
 545 {
 546         const struct xt_entry_target *t;
 547         unsigned int verdict;
 548
 549         if (!unconditional(&e->arp))
 550                 return false;
 551         t = arpt_get_target_c(e);
 552         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 553                 return false;
 554         verdict = ((struct xt_standard_target *)t)->verdict;
 555         verdict = -verdict - 1;
 556         return verdict == NF_DROP || verdict == NF_ACCEPT;
 557 }
 558
 559 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 560                                              struct xt_table_info *newinfo,
 561                                              const unsigned char *base,
 562                                              const unsigned char *limit,
 563                                              const unsigned int *hook_entries,
 564                                              const unsigned int *underflows,
 565                                              unsigned int valid_hooks)
 566 {
 567         unsigned int h;
 568
 569         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 570             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 571                 duprintf("Bad offset %p\n", e);
 572                 return -EINVAL;
 573         }
 574
 575         if (e->next_offset
 576             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 577                 duprintf("checking: element %p size %u\n",
 578                          e, e->next_offset);
 579                 return -EINVAL;
 580         }
 581
 582         /* Check hooks & underflows */
 583         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 584                 if (!(valid_hooks & (1 << h)))
 585                         continue;
 586                 if ((unsigned char *)e - base == hook_entries[h])
 587                         newinfo->hook_entry[h] = hook_entries[h];
 588                 if ((unsigned char *)e - base == underflows[h]) {
 589                         if (!check_underflow(e)) {
 590                                 pr_err("Underflows must be unconditional and "
 591                                        "use the STANDARD target with "
 592                                        "ACCEPT/DROP\n");
 593                                 return -EINVAL;
 594                         }
 595                         newinfo->underflow[h] = underflows[h];
 596                 }
 597         }
 598
 599         /* Clear counters and comefrom */
 600         e->counters = ((struct xt_counters) { 0, 0 });
 601         e->comefrom = 0;
 602         return 0;
 603 }
 604
 605 static inline void cleanup_entry(struct arpt_entry *e)
 606 {
 607         struct xt_tgdtor_param par;
 608         struct xt_entry_target *t;
 609
 610         t = arpt_get_target(e);
 611         par.target   = t->u.kernel.target;
 612         par.targinfo = t->data;
 613         par.family   = NFPROTO_ARP;
 614         if (par.target->destroy != NULL)
 615                 par.target->destroy(&par);
 616         module_put(par.target->me);
 617 }
 618
 619 /* Checks and translates the user-supplied table segment (held in
 620  * newinfo).
 621  */
 622 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 623                            const struct arpt_replace *repl)
 624 {
 625         struct arpt_entry *iter;
 626         unsigned int i;
 627         int ret = 0;
 628
 629         newinfo->size = repl->size;
 630         newinfo->number = repl->num_entries;
 631
 632         /* Init all hooks to impossible value. */
 633         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 634                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 635                 newinfo->underflow[i] = 0xFFFFFFFF;
 636         }
 637
 638         duprintf("translate_table: size %u\n", newinfo->size);
 639         i = 0;
 640
 641         /* Walk through entries, checking offsets. */
 642         xt_entry_foreach(iter, entry0, newinfo->size) {
 643                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 644                                                  entry0 + repl->size,
 645                                                  repl->hook_entry,
 646                                                  repl->underflow,
 647                                                  repl->valid_hooks);
 648                 if (ret != 0)
 649                         break;
 650                 ++i;
 651                 if (strcmp(arpt_get_target(iter)->u.user.name,
 652                     XT_ERROR_TARGET) == 0)
 653                         ++newinfo->stacksize;
 654         }
 655         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 656         if (ret != 0)
 657                 return ret;
 658
 659         if (i != repl->num_entries) {
 660                 duprintf("translate_table: %u not %u entries\n",
 661                          i, repl->num_entries);
 662                 return -EINVAL;
 663         }
 664
 665         /* Check hooks all assigned */
 666         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 667                 /* Only hooks which are valid */
 668                 if (!(repl->valid_hooks & (1 << i)))
 669                         continue;
 670                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 671                         duprintf("Invalid hook entry %u %u\n",
 672                                  i, repl->hook_entry[i]);
 673                         return -EINVAL;
 674                 }
 675                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 676                         duprintf("Invalid underflow %u %u\n",
 677                                  i, repl->underflow[i]);
 678                         return -EINVAL;
 679                 }
 680         }
 681
 682         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 683                 duprintf("Looping hook\n");
 684                 return -ELOOP;
 685         }
 686
 687         /* Finally, each sanity check must pass */
 688         i = 0;
 689         xt_entry_foreach(iter, entry0, newinfo->size) {
 690                 ret = find_check_entry(iter, repl->name, repl->size);
 691                 if (ret != 0)
 692                         break;
 693                 ++i;
 694         }
 695
 696         if (ret != 0) {
 697                 xt_entry_foreach(iter, entry0, newinfo->size) {
 698                         if (i-- == 0)
 699                                 break;
 700                         cleanup_entry(iter);
 701                 }
 702                 return ret;
 703         }
 704
 705         /* And one copy for every other CPU */
 706         for_each_possible_cpu(i) {
 707                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 708                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 709         }
 710
 711         return ret;
 712 }
 713
 714 static void get_counters(const struct xt_table_info *t,
 715                          struct xt_counters counters[])
 716 {
 717         struct arpt_entry *iter;
 718         unsigned int cpu;
 719         unsigned int i;
 720
 721         for_each_possible_cpu(cpu) {
 722                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 723
 724                 i = 0;
 725                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 726                         u64 bcnt, pcnt;
 727                         unsigned int start;
 728
 729                         do {
 730                                 start = read_seqcount_begin(s);
 731                                 bcnt = iter->counters.bcnt;
 732                                 pcnt = iter->counters.pcnt;
 733                         } while (read_seqcount_retry(s, start));
 734
 735                         ADD_COUNTER(counters[i], bcnt, pcnt);
 736                         ++i;
 737                 }
 738         }
 739 }
 740
 741 static struct xt_counters *alloc_counters(const struct xt_table *table)
 742 {
 743         unsigned int countersize;
 744         struct xt_counters *counters;
 745         const struct xt_table_info *private = table->private;
 746
 747         /* We need atomic snapshot of counters: rest doesn't change
 748          * (other than comefrom, which userspace doesn't care
 749          * about).
 750          */
 751         countersize = sizeof(struct xt_counters) * private->number;
 752         counters = vzalloc(countersize);
 753
 754         if (counters == NULL)
 755                 return ERR_PTR(-ENOMEM);
 756
 757         get_counters(private, counters);
 758
 759         return counters;
 760 }
 761
 762 static int copy_entries_to_user(unsigned int total_size,
 763                                 const struct xt_table *table,
 764                                 void __user *userptr)
 765 {
 766         unsigned int off, num;
 767         const struct arpt_entry *e;
 768         struct xt_counters *counters;
 769         struct xt_table_info *private = table->private;
 770         int ret = 0;
 771         void *loc_cpu_entry;
 772
 773         counters = alloc_counters(table);
 774         if (IS_ERR(counters))
 775                 return PTR_ERR(counters);
 776
 777         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 778         /* ... then copy entire thing ... */
 779         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 780                 ret = -EFAULT;
 781                 goto free_counters;
 782         }
 783
 784         /* FIXME: use iterator macros --RR */
 785         /* ... then go back and fix counters and names */
 786         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 787                 const struct xt_entry_target *t;
 788
 789                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 790                 if (copy_to_user(userptr + off
 791                                  + offsetof(struct arpt_entry, counters),
 792                                  &counters[num],
 793                                  sizeof(counters[num])) != 0) {
 794                         ret = -EFAULT;
 795                         goto free_counters;
 796                 }
 797
 798                 t = arpt_get_target_c(e);
 799                 if (copy_to_user(userptr + off + e->target_offset
 800                                  + offsetof(struct xt_entry_target,
 801                                             u.user.name),
 802                                  t->u.kernel.target->name,
 803                                  strlen(t->u.kernel.target->name)+1) != 0) {
 804                         ret = -EFAULT;
 805                         goto free_counters;
 806                 }
 807         }
 808
 809  free_counters:
 810         vfree(counters);
 811         return ret;
 812 }
 813
 814 #ifdef CONFIG_COMPAT
 815 static void compat_standard_from_user(void *dst, const void *src)
 816 {
 817         int v = *(compat_int_t *)src;
 818
 819         if (v > 0)
 820                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 821         memcpy(dst, &v, sizeof(v));
 822 }
 823
 824 static int compat_standard_to_user(void __user *dst, const void *src)
 825 {
 826         compat_int_t cv = *(int *)src;
 827
 828         if (cv > 0)
 829                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 830         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 831 }
 832
 833 static int compat_calc_entry(const struct arpt_entry *e,
 834                              const struct xt_table_info *info,
 835                              const void *base, struct xt_table_info *newinfo)
 836 {
 837         const struct xt_entry_target *t;
 838         unsigned int entry_offset;
 839         int off, i, ret;
 840
 841         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 842         entry_offset = (void *)e - base;
 843
 844         t = arpt_get_target_c(e);
 845         off += xt_compat_target_offset(t->u.kernel.target);
 846         newinfo->size -= off;
 847         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 848         if (ret)
 849                 return ret;
 850
 851         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 852                 if (info->hook_entry[i] &&
 853                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 854                         newinfo->hook_entry[i] -= off;
 855                 if (info->underflow[i] &&
 856                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 857                         newinfo->underflow[i] -= off;
 858         }
 859         return 0;
 860 }
 861
 862 static int compat_table_info(const struct xt_table_info *info,
 863                              struct xt_table_info *newinfo)
 864 {
 865         struct arpt_entry *iter;
 866         void *loc_cpu_entry;
 867         int ret;
 868
 869         if (!newinfo || !info)
 870                 return -EINVAL;
 871
 872         /* we dont care about newinfo->entries[] */
 873         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 874         newinfo->initial_entries = 0;
 875         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 876         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 877         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 878                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 879                 if (ret != 0)
 880                         return ret;
 881         }
 882         return 0;
 883 }
 884 #endif
 885
 886 static int get_info(struct net *net, void __user *user,
 887                     const int *len, int compat)
 888 {
 889         char name[XT_TABLE_MAXNAMELEN];
 890         struct xt_table *t;
 891         int ret;
 892
 893         if (*len != sizeof(struct arpt_getinfo)) {
 894                 duprintf("length %u != %Zu\n", *len,
 895                          sizeof(struct arpt_getinfo));
 896                 return -EINVAL;
 897         }
 898
 899         if (copy_from_user(name, user, sizeof(name)) != 0)
 900                 return -EFAULT;
 901
 902         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 903 #ifdef CONFIG_COMPAT
 904         if (compat)
 905                 xt_compat_lock(NFPROTO_ARP);
 906 #endif
 907         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 908                                     "arptable_%s", name);
 909         if (!IS_ERR_OR_NULL(t)) {
 910                 struct arpt_getinfo info;
 911                 const struct xt_table_info *private = t->private;
 912 #ifdef CONFIG_COMPAT
 913                 struct xt_table_info tmp;
 914
 915                 if (compat) {
 916                         ret = compat_table_info(private, &tmp);
 917                         xt_compat_flush_offsets(NFPROTO_ARP);
 918                         private = &tmp;
 919                 }
 920 #endif
 921                 memset(&info, 0, sizeof(info));
 922                 info.valid_hooks = t->valid_hooks;
 923                 memcpy(info.hook_entry, private->hook_entry,
 924                        sizeof(info.hook_entry));
 925                 memcpy(info.underflow, private->underflow,
 926                        sizeof(info.underflow));
 927                 info.num_entries = private->number;
 928                 info.size = private->size;
 929                 strcpy(info.name, name);
 930
 931                 if (copy_to_user(user, &info, *len) != 0)
 932                         ret = -EFAULT;
 933                 else
 934                         ret = 0;
 935                 xt_table_unlock(t);
 936                 module_put(t->me);
 937         } else
 938                 ret = t ? PTR_ERR(t) : -ENOENT;
 939 #ifdef CONFIG_COMPAT
 940         if (compat)
 941                 xt_compat_unlock(NFPROTO_ARP);
 942 #endif
 943         return ret;
 944 }
 945
 946 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 947                        const int *len)
 948 {
 949         int ret;
 950         struct arpt_get_entries get;
 951         struct xt_table *t;
 952
 953         if (*len < sizeof(get)) {
 954                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 955                 return -EINVAL;
 956         }
 957         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 958                 return -EFAULT;
 959         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 960                 duprintf("get_entries: %u != %Zu\n", *len,
 961                          sizeof(struct arpt_get_entries) + get.size);
 962                 return -EINVAL;
 963         }
 964
 965         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 966         if (!IS_ERR_OR_NULL(t)) {
 967                 const struct xt_table_info *private = t->private;
 968
 969                 duprintf("t->private->number = %u\n",
 970                          private->number);
 971                 if (get.size == private->size)
 972                         ret = copy_entries_to_user(private->size,
 973                                                    t, uptr->entrytable);
 974                 else {
 975                         duprintf("get_entries: I've got %u not %u!\n",
 976                                  private->size, get.size);
 977                         ret = -EAGAIN;
 978                 }
 979                 module_put(t->me);
 980                 xt_table_unlock(t);
 981         } else
 982                 ret = t ? PTR_ERR(t) : -ENOENT;
 983
 984         return ret;
 985 }
 986
 987 static int __do_replace(struct net *net, const char *name,
 988                         unsigned int valid_hooks,
 989                         struct xt_table_info *newinfo,
 990                         unsigned int num_counters,
 991                         void __user *counters_ptr)
 992 {
 993         int ret;
 994         struct xt_table *t;
 995         struct xt_table_info *oldinfo;
 996         struct xt_counters *counters;
 997         void *loc_cpu_old_entry;
 998         struct arpt_entry *iter;
 999
1000         ret = 0;
1001         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1002         if (!counters) {
1003                 ret = -ENOMEM;
1004                 goto out;
1005         }
1006
1007         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1008                                     "arptable_%s", name);
1009         if (IS_ERR_OR_NULL(t)) {
1010                 ret = t ? PTR_ERR(t) : -ENOENT;
1011                 goto free_newinfo_counters_untrans;
1012         }
1013
1014         /* You lied! */
1015         if (valid_hooks != t->valid_hooks) {
1016                 duprintf("Valid hook crap: %08X vs %08X\n",
1017                          valid_hooks, t->valid_hooks);
1018                 ret = -EINVAL;
1019                 goto put_module;
1020         }
1021
1022         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1023         if (!oldinfo)
1024                 goto put_module;
1025
1026         /* Update module usage count based on number of rules */
1027         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1028                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1029         if ((oldinfo->number > oldinfo->initial_entries) ||
1030             (newinfo->number <= oldinfo->initial_entries))
1031                 module_put(t->me);
1032         if ((oldinfo->number > oldinfo->initial_entries) &&
1033             (newinfo->number <= oldinfo->initial_entries))
1034                 module_put(t->me);
1035
1036         /* Get the old counters, and synchronize with replace */
1037         get_counters(oldinfo, counters);
1038
1039         /* Decrease module usage counts and free resource */
1040         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1041         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1042                 cleanup_entry(iter);
1043
1044         xt_free_table_info(oldinfo);
1045         if (copy_to_user(counters_ptr, counters,
1046                          sizeof(struct xt_counters) * num_counters) != 0) {
1047                 /* Silent error, can't fail, new table is already in place */
1048                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1049         }
1050         vfree(counters);
1051         xt_table_unlock(t);
1052         return ret;
1053
1054  put_module:
1055         module_put(t->me);
1056         xt_table_unlock(t);
1057  free_newinfo_counters_untrans:
1058         vfree(counters);
1059  out:
1060         return ret;
1061 }
1062
1063 static int do_replace(struct net *net, const void __user *user,
1064                       unsigned int len)
1065 {
1066         int ret;
1067         struct arpt_replace tmp;
1068         struct xt_table_info *newinfo;
1069         void *loc_cpu_entry;
1070         struct arpt_entry *iter;
1071
1072         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1073                 return -EFAULT;
1074
1075         /* overflow check */
1076         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1077                 return -ENOMEM;
1078         if (tmp.num_counters == 0)
1079                 return -EINVAL;
1080
1081         tmp.name[sizeof(tmp.name)-1] = 0;
1082
1083         newinfo = xt_alloc_table_info(tmp.size);
1084         if (!newinfo)
1085                 return -ENOMEM;
1086
1087         /* choose the copy that is on our node/cpu */
1088         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1089         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1090                            tmp.size) != 0) {
1091                 ret = -EFAULT;
1092                 goto free_newinfo;
1093         }
1094
1095         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1096         if (ret != 0)
1097                 goto free_newinfo;
1098
1099         duprintf("arp_tables: Translated table\n");
1100
1101         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1102                            tmp.num_counters, tmp.counters);
1103         if (ret)
1104                 goto free_newinfo_untrans;
1105         return 0;
1106
1107  free_newinfo_untrans:
1108         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1109                 cleanup_entry(iter);
1110  free_newinfo:
1111         xt_free_table_info(newinfo);
1112         return ret;
1113 }
1114
1115 static int do_add_counters(struct net *net, const void __user *user,
1116                            unsigned int len, int compat)
1117 {
1118         unsigned int i, curcpu;
1119         struct xt_counters_info tmp;
1120         struct xt_counters *paddc;
1121         unsigned int num_counters;
1122         const char *name;
1123         int size;
1124         void *ptmp;
1125         struct xt_table *t;
1126         const struct xt_table_info *private;
1127         int ret = 0;
1128         void *loc_cpu_entry;
1129         struct arpt_entry *iter;
1130         unsigned int addend;
1131 #ifdef CONFIG_COMPAT
1132         struct compat_xt_counters_info compat_tmp;
1133
1134         if (compat) {
1135                 ptmp = &compat_tmp;
1136                 size = sizeof(struct compat_xt_counters_info);
1137         } else
1138 #endif
1139         {
1140                 ptmp = &tmp;
1141                 size = sizeof(struct xt_counters_info);
1142         }
1143
1144         if (copy_from_user(ptmp, user, size) != 0)
1145                 return -EFAULT;
1146
1147 #ifdef CONFIG_COMPAT
1148         if (compat) {
1149                 num_counters = compat_tmp.num_counters;
1150                 name = compat_tmp.name;
1151         } else
1152 #endif
1153         {
1154                 num_counters = tmp.num_counters;
1155                 name = tmp.name;
1156         }
1157
1158         if (len != size + num_counters * sizeof(struct xt_counters))
1159                 return -EINVAL;
1160
1161         paddc = vmalloc(len - size);
1162         if (!paddc)
1163                 return -ENOMEM;
1164
1165         if (copy_from_user(paddc, user + size, len - size) != 0) {
1166                 ret = -EFAULT;
1167                 goto free;
1168         }
1169
1170         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1171         if (IS_ERR_OR_NULL(t)) {
1172                 ret = t ? PTR_ERR(t) : -ENOENT;
1173                 goto free;
1174         }
1175
1176         local_bh_disable();
1177         private = t->private;
1178         if (private->number != num_counters) {
1179                 ret = -EINVAL;
1180                 goto unlock_up_free;
1181         }
1182
1183         i = 0;
1184         /* Choose the copy that is on our node */
1185         curcpu = smp_processor_id();
1186         loc_cpu_entry = private->entries[curcpu];
1187         addend = xt_write_recseq_begin();
1188         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1189                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1190                 ++i;
1191         }
1192         xt_write_recseq_end(addend);
1193  unlock_up_free:
1194         local_bh_enable();
1195         xt_table_unlock(t);
1196         module_put(t->me);
1197  free:
1198         vfree(paddc);
1199
1200         return ret;
1201 }
1202
1203 #ifdef CONFIG_COMPAT
1204 static inline void compat_release_entry(struct compat_arpt_entry *e)
1205 {
1206         struct xt_entry_target *t;
1207
1208         t = compat_arpt_get_target(e);
1209         module_put(t->u.kernel.target->me);
1210 }
1211
1212 static inline int
1213 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1214                                   struct xt_table_info *newinfo,
1215                                   unsigned int *size,
1216                                   const unsigned char *base,
1217                                   const unsigned char *limit,
1218                                   const unsigned int *hook_entries,
1219                                   const unsigned int *underflows,
1220                                   const char *name)
1221 {
1222         struct xt_entry_target *t;
1223         struct xt_target *target;
1224         unsigned int entry_offset;
1225         int ret, off, h;
1226
1227         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1228         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1229             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1230                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1231                 return -EINVAL;
1232         }
1233
1234         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1235                              sizeof(struct compat_xt_entry_target)) {
1236                 duprintf("checking: element %p size %u\n",
1237                          e, e->next_offset);
1238                 return -EINVAL;
1239         }
1240
1241         /* For purposes of check_entry casting the compat entry is fine */
1242         ret = check_entry((struct arpt_entry *)e, name);
1243         if (ret)
1244                 return ret;
1245
1246         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1247         entry_offset = (void *)e - (void *)base;
1248
1249         t = compat_arpt_get_target(e);
1250         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1251                                         t->u.user.revision);
1252         if (IS_ERR(target)) {
1253                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1254                          t->u.user.name);
1255                 ret = PTR_ERR(target);
1256                 goto out;
1257         }
1258         t->u.kernel.target = target;
1259
1260         off += xt_compat_target_offset(target);
1261         *size += off;
1262         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1263         if (ret)
1264                 goto release_target;
1265
1266         /* Check hooks & underflows */
1267         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1268                 if ((unsigned char *)e - base == hook_entries[h])
1269                         newinfo->hook_entry[h] = hook_entries[h];
1270                 if ((unsigned char *)e - base == underflows[h])
1271                         newinfo->underflow[h] = underflows[h];
1272         }
1273
1274         /* Clear counters and comefrom */
1275         memset(&e->counters, 0, sizeof(e->counters));
1276         e->comefrom = 0;
1277         return 0;
1278
1279 release_target:
1280         module_put(t->u.kernel.target->me);
1281 out:
1282         return ret;
1283 }
1284
1285 static int
1286 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1287                             unsigned int *size, const char *name,
1288                             struct xt_table_info *newinfo, unsigned char *base)
1289 {
1290         struct xt_entry_target *t;
1291         struct xt_target *target;
1292         struct arpt_entry *de;
1293         unsigned int origsize;
1294         int ret, h;
1295
1296         ret = 0;
1297         origsize = *size;
1298         de = (struct arpt_entry *)*dstptr;
1299         memcpy(de, e, sizeof(struct arpt_entry));
1300         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1301
1302         *dstptr += sizeof(struct arpt_entry);
1303         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1304
1305         de->target_offset = e->target_offset - (origsize - *size);
1306         t = compat_arpt_get_target(e);
1307         target = t->u.kernel.target;
1308         xt_compat_target_from_user(t, dstptr, size);
1309
1310         de->next_offset = e->next_offset - (origsize - *size);
1311         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1312                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1313                         newinfo->hook_entry[h] -= origsize - *size;
1314                 if ((unsigned char *)de - base < newinfo->underflow[h])
1315                         newinfo->underflow[h] -= origsize - *size;
1316         }
1317         return ret;
1318 }
1319
1320 static int translate_compat_table(const char *name,
1321                                   unsigned int valid_hooks,
1322                                   struct xt_table_info **pinfo,
1323                                   void **pentry0,
1324                                   unsigned int total_size,
1325                                   unsigned int number,
1326                                   unsigned int *hook_entries,
1327                                   unsigned int *underflows)
1328 {
1329         unsigned int i, j;
1330         struct xt_table_info *newinfo, *info;
1331         void *pos, *entry0, *entry1;
1332         struct compat_arpt_entry *iter0;
1333         struct arpt_entry *iter1;
1334         unsigned int size;
1335         int ret = 0;
1336
1337         info = *pinfo;
1338         entry0 = *pentry0;
1339         size = total_size;
1340         info->number = number;
1341
1342         /* Init all hooks to impossible value. */
1343         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1344                 info->hook_entry[i] = 0xFFFFFFFF;
1345                 info->underflow[i] = 0xFFFFFFFF;
1346         }
1347
1348         duprintf("translate_compat_table: size %u\n", info->size);
1349         j = 0;
1350         xt_compat_lock(NFPROTO_ARP);
1351         xt_compat_init_offsets(NFPROTO_ARP, number);
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[XT_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         if (tmp.num_counters == 0)
1506                 return -EINVAL;
1507
1508         tmp.name[sizeof(tmp.name)-1] = 0;
1509
1510         newinfo = xt_alloc_table_info(tmp.size);
1511         if (!newinfo)
1512                 return -ENOMEM;
1513
1514         /* choose the copy that is on our node/cpu */
1515         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1516         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1517                 ret = -EFAULT;
1518                 goto free_newinfo;
1519         }
1520
1521         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1522                                      &newinfo, &loc_cpu_entry, tmp.size,
1523                                      tmp.num_entries, tmp.hook_entry,
1524                                      tmp.underflow);
1525         if (ret != 0)
1526                 goto free_newinfo;
1527
1528         duprintf("compat_do_replace: Translated table\n");
1529
1530         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1531                            tmp.num_counters, compat_ptr(tmp.counters));
1532         if (ret)
1533                 goto free_newinfo_untrans;
1534         return 0;
1535
1536  free_newinfo_untrans:
1537         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1538                 cleanup_entry(iter);
1539  free_newinfo:
1540         xt_free_table_info(newinfo);
1541         return ret;
1542 }
1543
1544 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1545                                   unsigned int len)
1546 {
1547         int ret;
1548
1549         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1550                 return -EPERM;
1551
1552         switch (cmd) {
1553         case ARPT_SO_SET_REPLACE:
1554                 ret = compat_do_replace(sock_net(sk), user, len);
1555                 break;
1556
1557         case ARPT_SO_SET_ADD_COUNTERS:
1558                 ret = do_add_counters(sock_net(sk), user, len, 1);
1559                 break;
1560
1561         default:
1562                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1563                 ret = -EINVAL;
1564         }
1565
1566         return ret;
1567 }
1568
1569 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1570                                      compat_uint_t *size,
1571                                      struct xt_counters *counters,
1572                                      unsigned int i)
1573 {
1574         struct xt_entry_target *t;
1575         struct compat_arpt_entry __user *ce;
1576         u_int16_t target_offset, next_offset;
1577         compat_uint_t origsize;
1578         int ret;
1579
1580         origsize = *size;
1581         ce = (struct compat_arpt_entry __user *)*dstptr;
1582         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1583             copy_to_user(&ce->counters, &counters[i],
1584             sizeof(counters[i])) != 0)
1585                 return -EFAULT;
1586
1587         *dstptr += sizeof(struct compat_arpt_entry);
1588         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1589
1590         target_offset = e->target_offset - (origsize - *size);
1591
1592         t = arpt_get_target(e);
1593         ret = xt_compat_target_to_user(t, dstptr, size);
1594         if (ret)
1595                 return ret;
1596         next_offset = e->next_offset - (origsize - *size);
1597         if (put_user(target_offset, &ce->target_offset) != 0 ||
1598             put_user(next_offset, &ce->next_offset) != 0)
1599                 return -EFAULT;
1600         return 0;
1601 }
1602
1603 static int compat_copy_entries_to_user(unsigned int total_size,
1604                                        struct xt_table *table,
1605                                        void __user *userptr)
1606 {
1607         struct xt_counters *counters;
1608         const struct xt_table_info *private = table->private;
1609         void __user *pos;
1610         unsigned int size;
1611         int ret = 0;
1612         void *loc_cpu_entry;
1613         unsigned int i = 0;
1614         struct arpt_entry *iter;
1615
1616         counters = alloc_counters(table);
1617         if (IS_ERR(counters))
1618                 return PTR_ERR(counters);
1619
1620         /* choose the copy on our node/cpu */
1621         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1622         pos = userptr;
1623         size = total_size;
1624         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1625                 ret = compat_copy_entry_to_user(iter, &pos,
1626                                                 &size, counters, i++);
1627                 if (ret != 0)
1628                         break;
1629         }
1630         vfree(counters);
1631         return ret;
1632 }
1633
1634 struct compat_arpt_get_entries {
1635         char name[XT_TABLE_MAXNAMELEN];
1636         compat_uint_t size;
1637         struct compat_arpt_entry entrytable[0];
1638 };
1639
1640 static int compat_get_entries(struct net *net,
1641                               struct compat_arpt_get_entries __user *uptr,
1642                               int *len)
1643 {
1644         int ret;
1645         struct compat_arpt_get_entries get;
1646         struct xt_table *t;
1647
1648         if (*len < sizeof(get)) {
1649                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1650                 return -EINVAL;
1651         }
1652         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1653                 return -EFAULT;
1654         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1655                 duprintf("compat_get_entries: %u != %zu\n",
1656                          *len, sizeof(get) + get.size);
1657                 return -EINVAL;
1658         }
1659
1660         xt_compat_lock(NFPROTO_ARP);
1661         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1662         if (!IS_ERR_OR_NULL(t)) {
1663                 const struct xt_table_info *private = t->private;
1664                 struct xt_table_info info;
1665
1666                 duprintf("t->private->number = %u\n", private->number);
1667                 ret = compat_table_info(private, &info);
1668                 if (!ret && get.size == info.size) {
1669                         ret = compat_copy_entries_to_user(private->size,
1670                                                           t, uptr->entrytable);
1671                 } else if (!ret) {
1672                         duprintf("compat_get_entries: I've got %u not %u!\n",
1673                                  private->size, get.size);
1674                         ret = -EAGAIN;
1675                 }
1676                 xt_compat_flush_offsets(NFPROTO_ARP);
1677                 module_put(t->me);
1678                 xt_table_unlock(t);
1679         } else
1680                 ret = t ? PTR_ERR(t) : -ENOENT;
1681
1682         xt_compat_unlock(NFPROTO_ARP);
1683         return ret;
1684 }
1685
1686 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1687
1688 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1689                                   int *len)
1690 {
1691         int ret;
1692
1693         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1694                 return -EPERM;
1695
1696         switch (cmd) {
1697         case ARPT_SO_GET_INFO:
1698                 ret = get_info(sock_net(sk), user, len, 1);
1699                 break;
1700         case ARPT_SO_GET_ENTRIES:
1701                 ret = compat_get_entries(sock_net(sk), user, len);
1702                 break;
1703         default:
1704                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1705         }
1706         return ret;
1707 }
1708 #endif
1709
1710 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1711 {
1712         int ret;
1713
1714         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1715                 return -EPERM;
1716
1717         switch (cmd) {
1718         case ARPT_SO_SET_REPLACE:
1719                 ret = do_replace(sock_net(sk), user, len);
1720                 break;
1721
1722         case ARPT_SO_SET_ADD_COUNTERS:
1723                 ret = do_add_counters(sock_net(sk), user, len, 0);
1724                 break;
1725
1726         default:
1727                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1728                 ret = -EINVAL;
1729         }
1730
1731         return ret;
1732 }
1733
1734 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1735 {
1736         int ret;
1737
1738         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1739                 return -EPERM;
1740
1741         switch (cmd) {
1742         case ARPT_SO_GET_INFO:
1743                 ret = get_info(sock_net(sk), user, len, 0);
1744                 break;
1745
1746         case ARPT_SO_GET_ENTRIES:
1747                 ret = get_entries(sock_net(sk), user, len);
1748                 break;
1749
1750         case ARPT_SO_GET_REVISION_TARGET: {
1751                 struct xt_get_revision rev;
1752
1753                 if (*len != sizeof(rev)) {
1754                         ret = -EINVAL;
1755                         break;
1756                 }
1757                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1758                         ret = -EFAULT;
1759                         break;
1760                 }
1761                 rev.name[sizeof(rev.name)-1] = 0;
1762
1763                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1764                                                          rev.revision, 1, &ret),
1765                                         "arpt_%s", rev.name);
1766                 break;
1767         }
1768
1769         default:
1770                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1771                 ret = -EINVAL;
1772         }
1773
1774         return ret;
1775 }
1776
1777 struct xt_table *arpt_register_table(struct net *net,
1778                                      const struct xt_table *table,
1779                                      const struct arpt_replace *repl)
1780 {
1781         int ret;
1782         struct xt_table_info *newinfo;
1783         struct xt_table_info bootstrap = {0};
1784         void *loc_cpu_entry;
1785         struct xt_table *new_table;
1786
1787         newinfo = xt_alloc_table_info(repl->size);
1788         if (!newinfo) {
1789                 ret = -ENOMEM;
1790                 goto out;
1791         }
1792
1793         /* choose the copy on our node/cpu */
1794         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1795         memcpy(loc_cpu_entry, repl->entries, repl->size);
1796
1797         ret = translate_table(newinfo, loc_cpu_entry, repl);
1798         duprintf("arpt_register_table: translate table gives %d\n", ret);
1799         if (ret != 0)
1800                 goto out_free;
1801
1802         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1803         if (IS_ERR(new_table)) {
1804                 ret = PTR_ERR(new_table);
1805                 goto out_free;
1806         }
1807         return new_table;
1808
1809 out_free:
1810         xt_free_table_info(newinfo);
1811 out:
1812         return ERR_PTR(ret);
1813 }
1814
1815 void arpt_unregister_table(struct xt_table *table)
1816 {
1817         struct xt_table_info *private;
1818         void *loc_cpu_entry;
1819         struct module *table_owner = table->me;
1820         struct arpt_entry *iter;
1821
1822         private = xt_unregister_table(table);
1823
1824         /* Decrease module usage counts and free resources */
1825         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1826         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1827                 cleanup_entry(iter);
1828         if (private->number > private->initial_entries)
1829                 module_put(table_owner);
1830         xt_free_table_info(private);
1831 }
1832
1833 /* The built-in targets: standard (NULL) and error. */
1834 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1835         {
1836                 .name             = XT_STANDARD_TARGET,
1837                 .targetsize       = sizeof(int),
1838                 .family           = NFPROTO_ARP,
1839 #ifdef CONFIG_COMPAT
1840                 .compatsize       = sizeof(compat_int_t),
1841                 .compat_from_user = compat_standard_from_user,
1842                 .compat_to_user   = compat_standard_to_user,
1843 #endif
1844         },
1845         {
1846                 .name             = XT_ERROR_TARGET,
1847                 .target           = arpt_error,
1848                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1849                 .family           = NFPROTO_ARP,
1850         },
1851 };
1852
1853 static struct nf_sockopt_ops arpt_sockopts = {
1854         .pf             = PF_INET,
1855         .set_optmin     = ARPT_BASE_CTL,
1856         .set_optmax     = ARPT_SO_SET_MAX+1,
1857         .set            = do_arpt_set_ctl,
1858 #ifdef CONFIG_COMPAT
1859         .compat_set     = compat_do_arpt_set_ctl,
1860 #endif
1861         .get_optmin     = ARPT_BASE_CTL,
1862         .get_optmax     = ARPT_SO_GET_MAX+1,
1863         .get            = do_arpt_get_ctl,
1864 #ifdef CONFIG_COMPAT
1865         .compat_get     = compat_do_arpt_get_ctl,
1866 #endif
1867         .owner          = THIS_MODULE,
1868 };
1869
1870 static int __net_init arp_tables_net_init(struct net *net)
1871 {
1872         return xt_proto_init(net, NFPROTO_ARP);
1873 }
1874
1875 static void __net_exit arp_tables_net_exit(struct net *net)
1876 {
1877         xt_proto_fini(net, NFPROTO_ARP);
1878 }
1879
1880 static struct pernet_operations arp_tables_net_ops = {
1881         .init = arp_tables_net_init,
1882         .exit = arp_tables_net_exit,
1883 };
1884
1885 static int __init arp_tables_init(void)
1886 {
1887         int ret;
1888
1889         ret = register_pernet_subsys(&arp_tables_net_ops);
1890         if (ret < 0)
1891                 goto err1;
1892
1893         /* No one else will be downing sem now, so we won't sleep */
1894         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1895         if (ret < 0)
1896                 goto err2;
1897
1898         /* Register setsockopt */
1899         ret = nf_register_sockopt(&arpt_sockopts);
1900         if (ret < 0)
1901                 goto err4;
1902
1903         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1904         return 0;
1905
1906 err4:
1907         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1908 err2:
1909         unregister_pernet_subsys(&arp_tables_net_ops);
1910 err1:
1911         return ret;
1912 }
1913
1914 static void __exit arp_tables_fini(void)
1915 {
1916         nf_unregister_sockopt(&arpt_sockopts);
1917         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1918         unregister_pernet_subsys(&arp_tables_net_ops);
1919 }
1920
1921 EXPORT_SYMBOL(arpt_register_table);
1922 EXPORT_SYMBOL(arpt_unregister_table);
1923 EXPORT_SYMBOL(arpt_do_table);
1924
1925 module_init(arp_tables_init);
1926 module_exit(arp_tables_fini);