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...)  pr_debug(format, ## args)
  42 #else
  43 #define dprintf(format, args...)
  44 #endif
  45
  46 #ifdef DEBUG_ARP_TABLES_USER
  47 #define duprintf(format, args...) pr_debug(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
 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                            const struct nf_hook_state *state,
 251                            struct xt_table *table)
 252 {
 253         unsigned int hook = state->hook;
 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, **jumpstack;
 258         const char *indev, *outdev;
 259         const void *table_base;
 260         unsigned int cpu, stackidx = 0;
 261         const struct xt_table_info *private;
 262         struct xt_action_param acpar;
 263         unsigned int addend;
 264
 265         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 266                 return NF_DROP;
 267
 268         indev = state->in ? state->in->name : nulldevname;
 269         outdev = state->out ? state->out->name : nulldevname;
 270
 271         local_bh_disable();
 272         addend = xt_write_recseq_begin();
 273         private = table->private;
 274         cpu     = smp_processor_id();
 275         /*
 276          * Ensure we load private-> members after we've fetched the base
 277          * pointer.
 278          */
 279         smp_read_barrier_depends();
 280         table_base = private->entries;
 281         jumpstack  = (struct arpt_entry **)private->jumpstack[cpu];
 282
 283         /* No TEE support for arptables, so no need to switch to alternate
 284          * stack.  All targets that reenter must return absolute verdicts.
 285          */
 286         e = get_entry(table_base, private->hook_entry[hook]);
 287
 288         acpar.net     = state->net;
 289         acpar.in      = state->in;
 290         acpar.out     = state->out;
 291         acpar.hooknum = hook;
 292         acpar.family  = NFPROTO_ARP;
 293         acpar.hotdrop = false;
 294
 295         arp = arp_hdr(skb);
 296         do {
 297                 const struct xt_entry_target *t;
 298                 struct xt_counters *counter;
 299
 300                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 301                         e = arpt_next_entry(e);
 302                         continue;
 303                 }
 304
 305                 counter = xt_get_this_cpu_counter(&e->counters);
 306                 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
 307
 308                 t = arpt_get_target_c(e);
 309
 310                 /* Standard target? */
 311                 if (!t->u.kernel.target->target) {
 312                         int v;
 313
 314                         v = ((struct xt_standard_target *)t)->verdict;
 315                         if (v < 0) {
 316                                 /* Pop from stack? */
 317                                 if (v != XT_RETURN) {
 318                                         verdict = (unsigned int)(-v) - 1;
 319                                         break;
 320                                 }
 321                                 if (stackidx == 0) {
 322                                         e = get_entry(table_base,
 323                                                       private->underflow[hook]);
 324                                 } else {
 325                                         e = jumpstack[--stackidx];
 326                                         e = arpt_next_entry(e);
 327                                 }
 328                                 continue;
 329                         }
 330                         if (table_base + v
 331                             != arpt_next_entry(e)) {
 332                                 jumpstack[stackidx++] = e;
 333                         }
 334
 335                         e = get_entry(table_base, v);
 336                         continue;
 337                 }
 338
 339                 acpar.target   = t->u.kernel.target;
 340                 acpar.targinfo = t->data;
 341                 verdict = t->u.kernel.target->target(skb, &acpar);
 342
 343                 /* Target might have changed stuff. */
 344                 arp = arp_hdr(skb);
 345
 346                 if (verdict == XT_CONTINUE)
 347                         e = arpt_next_entry(e);
 348                 else
 349                         /* Verdict */
 350                         break;
 351         } while (!acpar.hotdrop);
 352         xt_write_recseq_end(addend);
 353         local_bh_enable();
 354
 355         if (acpar.hotdrop)
 356                 return NF_DROP;
 357         else
 358                 return verdict;
 359 }
 360
 361 /* All zeroes == unconditional rule. */
 362 static inline bool unconditional(const struct arpt_entry *e)
 363 {
 364         static const struct arpt_arp uncond;
 365
 366         return e->target_offset == sizeof(struct arpt_entry) &&
 367                memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
 368 }
 369
 370 static bool find_jump_target(const struct xt_table_info *t,
 371                              const struct arpt_entry *target)
 372 {
 373         struct arpt_entry *iter;
 374
 375         xt_entry_foreach(iter, t->entries, t->size) {
 376                  if (iter == target)
 377                         return true;
 378         }
 379         return false;
 380 }
 381
 382 /* Figures out from what hook each rule can be called: returns 0 if
 383  * there are loops.  Puts hook bitmask in comefrom.
 384  */
 385 static int mark_source_chains(const struct xt_table_info *newinfo,
 386                               unsigned int valid_hooks, void *entry0)
 387 {
 388         unsigned int hook;
 389
 390         /* No recursion; use packet counter to save back ptrs (reset
 391          * to 0 as we leave), and comefrom to save source hook bitmask.
 392          */
 393         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 394                 unsigned int pos = newinfo->hook_entry[hook];
 395                 struct arpt_entry *e
 396                         = (struct arpt_entry *)(entry0 + pos);
 397
 398                 if (!(valid_hooks & (1 << hook)))
 399                         continue;
 400
 401                 /* Set initial back pointer. */
 402                 e->counters.pcnt = pos;
 403
 404                 for (;;) {
 405                         const struct xt_standard_target *t
 406                                 = (void *)arpt_get_target_c(e);
 407                         int visited = e->comefrom & (1 << hook);
 408
 409                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 410                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 411                                        hook, pos, e->comefrom);
 412                                 return 0;
 413                         }
 414                         e->comefrom
 415                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 416
 417                         /* Unconditional return/END. */
 418                         if ((unconditional(e) &&
 419                              (strcmp(t->target.u.user.name,
 420                                      XT_STANDARD_TARGET) == 0) &&
 421                              t->verdict < 0) || visited) {
 422                                 unsigned int oldpos, size;
 423
 424                                 if ((strcmp(t->target.u.user.name,
 425                                             XT_STANDARD_TARGET) == 0) &&
 426                                     t->verdict < -NF_MAX_VERDICT - 1) {
 427                                         duprintf("mark_source_chains: bad "
 428                                                 "negative verdict (%i)\n",
 429                                                                 t->verdict);
 430                                         return 0;
 431                                 }
 432
 433                                 /* Return: backtrack through the last
 434                                  * big jump.
 435                                  */
 436                                 do {
 437                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 438                                         oldpos = pos;
 439                                         pos = e->counters.pcnt;
 440                                         e->counters.pcnt = 0;
 441
 442                                         /* We're at the start. */
 443                                         if (pos == oldpos)
 444                                                 goto next;
 445
 446                                         e = (struct arpt_entry *)
 447                                                 (entry0 + pos);
 448                                 } while (oldpos == pos + e->next_offset);
 449
 450                                 /* Move along one */
 451                                 size = e->next_offset;
 452                                 e = (struct arpt_entry *)
 453                                         (entry0 + pos + size);
 454                                 if (pos + size >= newinfo->size)
 455                                         return 0;
 456                                 e->counters.pcnt = pos;
 457                                 pos += size;
 458                         } else {
 459                                 int newpos = t->verdict;
 460
 461                                 if (strcmp(t->target.u.user.name,
 462                                            XT_STANDARD_TARGET) == 0 &&
 463                                     newpos >= 0) {
 464                                         if (newpos > newinfo->size -
 465                                                 sizeof(struct arpt_entry)) {
 466                                                 duprintf("mark_source_chains: "
 467                                                         "bad verdict (%i)\n",
 468                                                                 newpos);
 469                                                 return 0;
 470                                         }
 471
 472                                         /* This a jump; chase it. */
 473                                         duprintf("Jump rule %u -> %u\n",
 474                                                  pos, newpos);
 475                                         e = (struct arpt_entry *)
 476                                                 (entry0 + newpos);
 477                                         if (!find_jump_target(newinfo, e))
 478                                                 return 0;
 479                                 } else {
 480                                         /* ... this is a fallthru */
 481                                         newpos = pos + e->next_offset;
 482                                         if (newpos >= newinfo->size)
 483                                                 return 0;
 484                                 }
 485                                 e = (struct arpt_entry *)
 486                                         (entry0 + newpos);
 487                                 e->counters.pcnt = pos;
 488                                 pos = newpos;
 489                         }
 490                 }
 491 next:
 492                 duprintf("Finished chain %u\n", hook);
 493         }
 494         return 1;
 495 }
 496
 497 static inline int check_target(struct arpt_entry *e, const char *name)
 498 {
 499         struct xt_entry_target *t = arpt_get_target(e);
 500         int ret;
 501         struct xt_tgchk_param par = {
 502                 .table     = name,
 503                 .entryinfo = e,
 504                 .target    = t->u.kernel.target,
 505                 .targinfo  = t->data,
 506                 .hook_mask = e->comefrom,
 507                 .family    = NFPROTO_ARP,
 508         };
 509
 510         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 511         if (ret < 0) {
 512                 duprintf("arp_tables: check failed for `%s'.\n",
 513                          t->u.kernel.target->name);
 514                 return ret;
 515         }
 516         return 0;
 517 }
 518
 519 static inline int
 520 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 521 {
 522         struct xt_entry_target *t;
 523         struct xt_target *target;
 524         int ret;
 525
 526         e->counters.pcnt = xt_percpu_counter_alloc();
 527         if (IS_ERR_VALUE(e->counters.pcnt))
 528                 return -ENOMEM;
 529
 530         t = arpt_get_target(e);
 531         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 532                                         t->u.user.revision);
 533         if (IS_ERR(target)) {
 534                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 535                 ret = PTR_ERR(target);
 536                 goto out;
 537         }
 538         t->u.kernel.target = target;
 539
 540         ret = check_target(e, name);
 541         if (ret)
 542                 goto err;
 543         return 0;
 544 err:
 545         module_put(t->u.kernel.target->me);
 546 out:
 547         xt_percpu_counter_free(e->counters.pcnt);
 548
 549         return ret;
 550 }
 551
 552 static bool check_underflow(const struct arpt_entry *e)
 553 {
 554         const struct xt_entry_target *t;
 555         unsigned int verdict;
 556
 557         if (!unconditional(e))
 558                 return false;
 559         t = arpt_get_target_c(e);
 560         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 561                 return false;
 562         verdict = ((struct xt_standard_target *)t)->verdict;
 563         verdict = -verdict - 1;
 564         return verdict == NF_DROP || verdict == NF_ACCEPT;
 565 }
 566
 567 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 568                                              struct xt_table_info *newinfo,
 569                                              const unsigned char *base,
 570                                              const unsigned char *limit,
 571                                              const unsigned int *hook_entries,
 572                                              const unsigned int *underflows,
 573                                              unsigned int valid_hooks)
 574 {
 575         unsigned int h;
 576         int err;
 577
 578         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 579             (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
 580             (unsigned char *)e + e->next_offset > limit) {
 581                 duprintf("Bad offset %p\n", e);
 582                 return -EINVAL;
 583         }
 584
 585         if (e->next_offset
 586             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 587                 duprintf("checking: element %p size %u\n",
 588                          e, e->next_offset);
 589                 return -EINVAL;
 590         }
 591
 592         if (!arp_checkentry(&e->arp))
 593                 return -EINVAL;
 594
 595         err = xt_check_entry_offsets(e, e->target_offset, e->next_offset);
 596         if (err)
 597                 return err;
 598
 599         /* Check hooks & underflows */
 600         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 601                 if (!(valid_hooks & (1 << h)))
 602                         continue;
 603                 if ((unsigned char *)e - base == hook_entries[h])
 604                         newinfo->hook_entry[h] = hook_entries[h];
 605                 if ((unsigned char *)e - base == underflows[h]) {
 606                         if (!check_underflow(e)) {
 607                                 pr_debug("Underflows must be unconditional and "
 608                                          "use the STANDARD target with "
 609                                          "ACCEPT/DROP\n");
 610                                 return -EINVAL;
 611                         }
 612                         newinfo->underflow[h] = underflows[h];
 613                 }
 614         }
 615
 616         /* Clear counters and comefrom */
 617         e->counters = ((struct xt_counters) { 0, 0 });
 618         e->comefrom = 0;
 619         return 0;
 620 }
 621
 622 static inline void cleanup_entry(struct arpt_entry *e)
 623 {
 624         struct xt_tgdtor_param par;
 625         struct xt_entry_target *t;
 626
 627         t = arpt_get_target(e);
 628         par.target   = t->u.kernel.target;
 629         par.targinfo = t->data;
 630         par.family   = NFPROTO_ARP;
 631         if (par.target->destroy != NULL)
 632                 par.target->destroy(&par);
 633         module_put(par.target->me);
 634         xt_percpu_counter_free(e->counters.pcnt);
 635 }
 636
 637 /* Checks and translates the user-supplied table segment (held in
 638  * newinfo).
 639  */
 640 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 641                            const struct arpt_replace *repl)
 642 {
 643         struct arpt_entry *iter;
 644         unsigned int i;
 645         int ret = 0;
 646
 647         newinfo->size = repl->size;
 648         newinfo->number = repl->num_entries;
 649
 650         /* Init all hooks to impossible value. */
 651         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 652                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 653                 newinfo->underflow[i] = 0xFFFFFFFF;
 654         }
 655
 656         duprintf("translate_table: size %u\n", newinfo->size);
 657         i = 0;
 658
 659         /* Walk through entries, checking offsets. */
 660         xt_entry_foreach(iter, entry0, newinfo->size) {
 661                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 662                                                  entry0 + repl->size,
 663                                                  repl->hook_entry,
 664                                                  repl->underflow,
 665                                                  repl->valid_hooks);
 666                 if (ret != 0)
 667                         break;
 668                 ++i;
 669                 if (strcmp(arpt_get_target(iter)->u.user.name,
 670                     XT_ERROR_TARGET) == 0)
 671                         ++newinfo->stacksize;
 672         }
 673         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 674         if (ret != 0)
 675                 return ret;
 676
 677         if (i != repl->num_entries) {
 678                 duprintf("translate_table: %u not %u entries\n",
 679                          i, repl->num_entries);
 680                 return -EINVAL;
 681         }
 682
 683         /* Check hooks all assigned */
 684         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 685                 /* Only hooks which are valid */
 686                 if (!(repl->valid_hooks & (1 << i)))
 687                         continue;
 688                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 689                         duprintf("Invalid hook entry %u %u\n",
 690                                  i, repl->hook_entry[i]);
 691                         return -EINVAL;
 692                 }
 693                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 694                         duprintf("Invalid underflow %u %u\n",
 695                                  i, repl->underflow[i]);
 696                         return -EINVAL;
 697                 }
 698         }
 699
 700         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
 701                 return -ELOOP;
 702
 703         /* Finally, each sanity check must pass */
 704         i = 0;
 705         xt_entry_foreach(iter, entry0, newinfo->size) {
 706                 ret = find_check_entry(iter, repl->name, repl->size);
 707                 if (ret != 0)
 708                         break;
 709                 ++i;
 710         }
 711
 712         if (ret != 0) {
 713                 xt_entry_foreach(iter, entry0, newinfo->size) {
 714                         if (i-- == 0)
 715                                 break;
 716                         cleanup_entry(iter);
 717                 }
 718                 return ret;
 719         }
 720
 721         return ret;
 722 }
 723
 724 static void get_counters(const struct xt_table_info *t,
 725                          struct xt_counters counters[])
 726 {
 727         struct arpt_entry *iter;
 728         unsigned int cpu;
 729         unsigned int i;
 730
 731         for_each_possible_cpu(cpu) {
 732                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 733
 734                 i = 0;
 735                 xt_entry_foreach(iter, t->entries, t->size) {
 736                         struct xt_counters *tmp;
 737                         u64 bcnt, pcnt;
 738                         unsigned int start;
 739
 740                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 741                         do {
 742                                 start = read_seqcount_begin(s);
 743                                 bcnt = tmp->bcnt;
 744                                 pcnt = tmp->pcnt;
 745                         } while (read_seqcount_retry(s, start));
 746
 747                         ADD_COUNTER(counters[i], bcnt, pcnt);
 748                         ++i;
 749                 }
 750         }
 751 }
 752
 753 static struct xt_counters *alloc_counters(const struct xt_table *table)
 754 {
 755         unsigned int countersize;
 756         struct xt_counters *counters;
 757         const struct xt_table_info *private = table->private;
 758
 759         /* We need atomic snapshot of counters: rest doesn't change
 760          * (other than comefrom, which userspace doesn't care
 761          * about).
 762          */
 763         countersize = sizeof(struct xt_counters) * private->number;
 764         counters = vzalloc(countersize);
 765
 766         if (counters == NULL)
 767                 return ERR_PTR(-ENOMEM);
 768
 769         get_counters(private, counters);
 770
 771         return counters;
 772 }
 773
 774 static int copy_entries_to_user(unsigned int total_size,
 775                                 const struct xt_table *table,
 776                                 void __user *userptr)
 777 {
 778         unsigned int off, num;
 779         const struct arpt_entry *e;
 780         struct xt_counters *counters;
 781         struct xt_table_info *private = table->private;
 782         int ret = 0;
 783         void *loc_cpu_entry;
 784
 785         counters = alloc_counters(table);
 786         if (IS_ERR(counters))
 787                 return PTR_ERR(counters);
 788
 789         loc_cpu_entry = private->entries;
 790         /* ... then copy entire thing ... */
 791         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 792                 ret = -EFAULT;
 793                 goto free_counters;
 794         }
 795
 796         /* FIXME: use iterator macros --RR */
 797         /* ... then go back and fix counters and names */
 798         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 799                 const struct xt_entry_target *t;
 800
 801                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 802                 if (copy_to_user(userptr + off
 803                                  + offsetof(struct arpt_entry, counters),
 804                                  &counters[num],
 805                                  sizeof(counters[num])) != 0) {
 806                         ret = -EFAULT;
 807                         goto free_counters;
 808                 }
 809
 810                 t = arpt_get_target_c(e);
 811                 if (copy_to_user(userptr + off + e->target_offset
 812                                  + offsetof(struct xt_entry_target,
 813                                             u.user.name),
 814                                  t->u.kernel.target->name,
 815                                  strlen(t->u.kernel.target->name)+1) != 0) {
 816                         ret = -EFAULT;
 817                         goto free_counters;
 818                 }
 819         }
 820
 821  free_counters:
 822         vfree(counters);
 823         return ret;
 824 }
 825
 826 #ifdef CONFIG_COMPAT
 827 static void compat_standard_from_user(void *dst, const void *src)
 828 {
 829         int v = *(compat_int_t *)src;
 830
 831         if (v > 0)
 832                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 833         memcpy(dst, &v, sizeof(v));
 834 }
 835
 836 static int compat_standard_to_user(void __user *dst, const void *src)
 837 {
 838         compat_int_t cv = *(int *)src;
 839
 840         if (cv > 0)
 841                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 842         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 843 }
 844
 845 static int compat_calc_entry(const struct arpt_entry *e,
 846                              const struct xt_table_info *info,
 847                              const void *base, struct xt_table_info *newinfo)
 848 {
 849         const struct xt_entry_target *t;
 850         unsigned int entry_offset;
 851         int off, i, ret;
 852
 853         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 854         entry_offset = (void *)e - base;
 855
 856         t = arpt_get_target_c(e);
 857         off += xt_compat_target_offset(t->u.kernel.target);
 858         newinfo->size -= off;
 859         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 860         if (ret)
 861                 return ret;
 862
 863         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 864                 if (info->hook_entry[i] &&
 865                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 866                         newinfo->hook_entry[i] -= off;
 867                 if (info->underflow[i] &&
 868                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 869                         newinfo->underflow[i] -= off;
 870         }
 871         return 0;
 872 }
 873
 874 static int compat_table_info(const struct xt_table_info *info,
 875                              struct xt_table_info *newinfo)
 876 {
 877         struct arpt_entry *iter;
 878         const void *loc_cpu_entry;
 879         int ret;
 880
 881         if (!newinfo || !info)
 882                 return -EINVAL;
 883
 884         /* we dont care about newinfo->entries */
 885         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 886         newinfo->initial_entries = 0;
 887         loc_cpu_entry = info->entries;
 888         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 889         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 890                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 891                 if (ret != 0)
 892                         return ret;
 893         }
 894         return 0;
 895 }
 896 #endif
 897
 898 static int get_info(struct net *net, void __user *user,
 899                     const int *len, int compat)
 900 {
 901         char name[XT_TABLE_MAXNAMELEN];
 902         struct xt_table *t;
 903         int ret;
 904
 905         if (*len != sizeof(struct arpt_getinfo)) {
 906                 duprintf("length %u != %Zu\n", *len,
 907                          sizeof(struct arpt_getinfo));
 908                 return -EINVAL;
 909         }
 910
 911         if (copy_from_user(name, user, sizeof(name)) != 0)
 912                 return -EFAULT;
 913
 914         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 915 #ifdef CONFIG_COMPAT
 916         if (compat)
 917                 xt_compat_lock(NFPROTO_ARP);
 918 #endif
 919         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 920                                     "arptable_%s", name);
 921         if (!IS_ERR_OR_NULL(t)) {
 922                 struct arpt_getinfo info;
 923                 const struct xt_table_info *private = t->private;
 924 #ifdef CONFIG_COMPAT
 925                 struct xt_table_info tmp;
 926
 927                 if (compat) {
 928                         ret = compat_table_info(private, &tmp);
 929                         xt_compat_flush_offsets(NFPROTO_ARP);
 930                         private = &tmp;
 931                 }
 932 #endif
 933                 memset(&info, 0, sizeof(info));
 934                 info.valid_hooks = t->valid_hooks;
 935                 memcpy(info.hook_entry, private->hook_entry,
 936                        sizeof(info.hook_entry));
 937                 memcpy(info.underflow, private->underflow,
 938                        sizeof(info.underflow));
 939                 info.num_entries = private->number;
 940                 info.size = private->size;
 941                 strcpy(info.name, name);
 942
 943                 if (copy_to_user(user, &info, *len) != 0)
 944                         ret = -EFAULT;
 945                 else
 946                         ret = 0;
 947                 xt_table_unlock(t);
 948                 module_put(t->me);
 949         } else
 950                 ret = t ? PTR_ERR(t) : -ENOENT;
 951 #ifdef CONFIG_COMPAT
 952         if (compat)
 953                 xt_compat_unlock(NFPROTO_ARP);
 954 #endif
 955         return ret;
 956 }
 957
 958 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 959                        const int *len)
 960 {
 961         int ret;
 962         struct arpt_get_entries get;
 963         struct xt_table *t;
 964
 965         if (*len < sizeof(get)) {
 966                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 967                 return -EINVAL;
 968         }
 969         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 970                 return -EFAULT;
 971         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 972                 duprintf("get_entries: %u != %Zu\n", *len,
 973                          sizeof(struct arpt_get_entries) + get.size);
 974                 return -EINVAL;
 975         }
 976         get.name[sizeof(get.name) - 1] = '\0';
 977
 978         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 979         if (!IS_ERR_OR_NULL(t)) {
 980                 const struct xt_table_info *private = t->private;
 981
 982                 duprintf("t->private->number = %u\n",
 983                          private->number);
 984                 if (get.size == private->size)
 985                         ret = copy_entries_to_user(private->size,
 986                                                    t, uptr->entrytable);
 987                 else {
 988                         duprintf("get_entries: I've got %u not %u!\n",
 989                                  private->size, get.size);
 990                         ret = -EAGAIN;
 991                 }
 992                 module_put(t->me);
 993                 xt_table_unlock(t);
 994         } else
 995                 ret = t ? PTR_ERR(t) : -ENOENT;
 996
 997         return ret;
 998 }
 999
1000 static int __do_replace(struct net *net, const char *name,
1001                         unsigned int valid_hooks,
1002                         struct xt_table_info *newinfo,
1003                         unsigned int num_counters,
1004                         void __user *counters_ptr)
1005 {
1006         int ret;
1007         struct xt_table *t;
1008         struct xt_table_info *oldinfo;
1009         struct xt_counters *counters;
1010         void *loc_cpu_old_entry;
1011         struct arpt_entry *iter;
1012
1013         ret = 0;
1014         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1015         if (!counters) {
1016                 ret = -ENOMEM;
1017                 goto out;
1018         }
1019
1020         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1021                                     "arptable_%s", name);
1022         if (IS_ERR_OR_NULL(t)) {
1023                 ret = t ? PTR_ERR(t) : -ENOENT;
1024                 goto free_newinfo_counters_untrans;
1025         }
1026
1027         /* You lied! */
1028         if (valid_hooks != t->valid_hooks) {
1029                 duprintf("Valid hook crap: %08X vs %08X\n",
1030                          valid_hooks, t->valid_hooks);
1031                 ret = -EINVAL;
1032                 goto put_module;
1033         }
1034
1035         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1036         if (!oldinfo)
1037                 goto put_module;
1038
1039         /* Update module usage count based on number of rules */
1040         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1041                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1042         if ((oldinfo->number > oldinfo->initial_entries) ||
1043             (newinfo->number <= oldinfo->initial_entries))
1044                 module_put(t->me);
1045         if ((oldinfo->number > oldinfo->initial_entries) &&
1046             (newinfo->number <= oldinfo->initial_entries))
1047                 module_put(t->me);
1048
1049         /* Get the old counters, and synchronize with replace */
1050         get_counters(oldinfo, counters);
1051
1052         /* Decrease module usage counts and free resource */
1053         loc_cpu_old_entry = oldinfo->entries;
1054         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1055                 cleanup_entry(iter);
1056
1057         xt_free_table_info(oldinfo);
1058         if (copy_to_user(counters_ptr, counters,
1059                          sizeof(struct xt_counters) * num_counters) != 0) {
1060                 /* Silent error, can't fail, new table is already in place */
1061                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1062         }
1063         vfree(counters);
1064         xt_table_unlock(t);
1065         return ret;
1066
1067  put_module:
1068         module_put(t->me);
1069         xt_table_unlock(t);
1070  free_newinfo_counters_untrans:
1071         vfree(counters);
1072  out:
1073         return ret;
1074 }
1075
1076 static int do_replace(struct net *net, const void __user *user,
1077                       unsigned int len)
1078 {
1079         int ret;
1080         struct arpt_replace tmp;
1081         struct xt_table_info *newinfo;
1082         void *loc_cpu_entry;
1083         struct arpt_entry *iter;
1084
1085         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1086                 return -EFAULT;
1087
1088         /* overflow check */
1089         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1090                 return -ENOMEM;
1091         if (tmp.num_counters == 0)
1092                 return -EINVAL;
1093
1094         tmp.name[sizeof(tmp.name)-1] = 0;
1095
1096         newinfo = xt_alloc_table_info(tmp.size);
1097         if (!newinfo)
1098                 return -ENOMEM;
1099
1100         loc_cpu_entry = newinfo->entries;
1101         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1102                            tmp.size) != 0) {
1103                 ret = -EFAULT;
1104                 goto free_newinfo;
1105         }
1106
1107         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1108         if (ret != 0)
1109                 goto free_newinfo;
1110
1111         duprintf("arp_tables: Translated table\n");
1112
1113         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1114                            tmp.num_counters, tmp.counters);
1115         if (ret)
1116                 goto free_newinfo_untrans;
1117         return 0;
1118
1119  free_newinfo_untrans:
1120         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1121                 cleanup_entry(iter);
1122  free_newinfo:
1123         xt_free_table_info(newinfo);
1124         return ret;
1125 }
1126
1127 static int do_add_counters(struct net *net, const void __user *user,
1128                            unsigned int len, int compat)
1129 {
1130         unsigned int i;
1131         struct xt_counters_info tmp;
1132         struct xt_counters *paddc;
1133         unsigned int num_counters;
1134         const char *name;
1135         int size;
1136         void *ptmp;
1137         struct xt_table *t;
1138         const struct xt_table_info *private;
1139         int ret = 0;
1140         struct arpt_entry *iter;
1141         unsigned int addend;
1142 #ifdef CONFIG_COMPAT
1143         struct compat_xt_counters_info compat_tmp;
1144
1145         if (compat) {
1146                 ptmp = &compat_tmp;
1147                 size = sizeof(struct compat_xt_counters_info);
1148         } else
1149 #endif
1150         {
1151                 ptmp = &tmp;
1152                 size = sizeof(struct xt_counters_info);
1153         }
1154
1155         if (copy_from_user(ptmp, user, size) != 0)
1156                 return -EFAULT;
1157
1158 #ifdef CONFIG_COMPAT
1159         if (compat) {
1160                 num_counters = compat_tmp.num_counters;
1161                 name = compat_tmp.name;
1162         } else
1163 #endif
1164         {
1165                 num_counters = tmp.num_counters;
1166                 name = tmp.name;
1167         }
1168
1169         if (len != size + num_counters * sizeof(struct xt_counters))
1170                 return -EINVAL;
1171
1172         paddc = vmalloc(len - size);
1173         if (!paddc)
1174                 return -ENOMEM;
1175
1176         if (copy_from_user(paddc, user + size, len - size) != 0) {
1177                 ret = -EFAULT;
1178                 goto free;
1179         }
1180
1181         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1182         if (IS_ERR_OR_NULL(t)) {
1183                 ret = t ? PTR_ERR(t) : -ENOENT;
1184                 goto free;
1185         }
1186
1187         local_bh_disable();
1188         private = t->private;
1189         if (private->number != num_counters) {
1190                 ret = -EINVAL;
1191                 goto unlock_up_free;
1192         }
1193
1194         i = 0;
1195
1196         addend = xt_write_recseq_begin();
1197         xt_entry_foreach(iter,  private->entries, private->size) {
1198                 struct xt_counters *tmp;
1199
1200                 tmp = xt_get_this_cpu_counter(&iter->counters);
1201                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1202                 ++i;
1203         }
1204         xt_write_recseq_end(addend);
1205  unlock_up_free:
1206         local_bh_enable();
1207         xt_table_unlock(t);
1208         module_put(t->me);
1209  free:
1210         vfree(paddc);
1211
1212         return ret;
1213 }
1214
1215 #ifdef CONFIG_COMPAT
1216 static inline void compat_release_entry(struct compat_arpt_entry *e)
1217 {
1218         struct xt_entry_target *t;
1219
1220         t = compat_arpt_get_target(e);
1221         module_put(t->u.kernel.target->me);
1222 }
1223
1224 static inline int
1225 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1226                                   struct xt_table_info *newinfo,
1227                                   unsigned int *size,
1228                                   const unsigned char *base,
1229                                   const unsigned char *limit,
1230                                   const unsigned int *hook_entries,
1231                                   const unsigned int *underflows,
1232                                   const char *name)
1233 {
1234         struct xt_entry_target *t;
1235         struct xt_target *target;
1236         unsigned int entry_offset;
1237         int ret, off, h;
1238
1239         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1240         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1241             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1242             (unsigned char *)e + e->next_offset > limit) {
1243                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1244                 return -EINVAL;
1245         }
1246
1247         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1248                              sizeof(struct compat_xt_entry_target)) {
1249                 duprintf("checking: element %p size %u\n",
1250                          e, e->next_offset);
1251                 return -EINVAL;
1252         }
1253
1254         if (!arp_checkentry(&e->arp))
1255                 return -EINVAL;
1256
1257         ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);
1258         if (ret)
1259                 return ret;
1260
1261         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1262         entry_offset = (void *)e - (void *)base;
1263
1264         t = compat_arpt_get_target(e);
1265         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1266                                         t->u.user.revision);
1267         if (IS_ERR(target)) {
1268                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1269                          t->u.user.name);
1270                 ret = PTR_ERR(target);
1271                 goto out;
1272         }
1273         t->u.kernel.target = target;
1274
1275         off += xt_compat_target_offset(target);
1276         *size += off;
1277         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1278         if (ret)
1279                 goto release_target;
1280
1281         /* Check hooks & underflows */
1282         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1283                 if ((unsigned char *)e - base == hook_entries[h])
1284                         newinfo->hook_entry[h] = hook_entries[h];
1285                 if ((unsigned char *)e - base == underflows[h])
1286                         newinfo->underflow[h] = underflows[h];
1287         }
1288
1289         /* Clear counters and comefrom */
1290         memset(&e->counters, 0, sizeof(e->counters));
1291         e->comefrom = 0;
1292         return 0;
1293
1294 release_target:
1295         module_put(t->u.kernel.target->me);
1296 out:
1297         return ret;
1298 }
1299
1300 static int
1301 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1302                             unsigned int *size, const char *name,
1303                             struct xt_table_info *newinfo, unsigned char *base)
1304 {
1305         struct xt_entry_target *t;
1306         struct xt_target *target;
1307         struct arpt_entry *de;
1308         unsigned int origsize;
1309         int ret, h;
1310
1311         ret = 0;
1312         origsize = *size;
1313         de = (struct arpt_entry *)*dstptr;
1314         memcpy(de, e, sizeof(struct arpt_entry));
1315         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1316
1317         *dstptr += sizeof(struct arpt_entry);
1318         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1319
1320         de->target_offset = e->target_offset - (origsize - *size);
1321         t = compat_arpt_get_target(e);
1322         target = t->u.kernel.target;
1323         xt_compat_target_from_user(t, dstptr, size);
1324
1325         de->next_offset = e->next_offset - (origsize - *size);
1326         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1327                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1328                         newinfo->hook_entry[h] -= origsize - *size;
1329                 if ((unsigned char *)de - base < newinfo->underflow[h])
1330                         newinfo->underflow[h] -= origsize - *size;
1331         }
1332         return ret;
1333 }
1334
1335 static int translate_compat_table(const char *name,
1336                                   unsigned int valid_hooks,
1337                                   struct xt_table_info **pinfo,
1338                                   void **pentry0,
1339                                   unsigned int total_size,
1340                                   unsigned int number,
1341                                   unsigned int *hook_entries,
1342                                   unsigned int *underflows)
1343 {
1344         unsigned int i, j;
1345         struct xt_table_info *newinfo, *info;
1346         void *pos, *entry0, *entry1;
1347         struct compat_arpt_entry *iter0;
1348         struct arpt_entry *iter1;
1349         unsigned int size;
1350         int ret = 0;
1351
1352         info = *pinfo;
1353         entry0 = *pentry0;
1354         size = total_size;
1355         info->number = number;
1356
1357         /* Init all hooks to impossible value. */
1358         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1359                 info->hook_entry[i] = 0xFFFFFFFF;
1360                 info->underflow[i] = 0xFFFFFFFF;
1361         }
1362
1363         duprintf("translate_compat_table: size %u\n", info->size);
1364         j = 0;
1365         xt_compat_lock(NFPROTO_ARP);
1366         xt_compat_init_offsets(NFPROTO_ARP, number);
1367         /* Walk through entries, checking offsets. */
1368         xt_entry_foreach(iter0, entry0, total_size) {
1369                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1370                                                         entry0,
1371                                                         entry0 + total_size,
1372                                                         hook_entries,
1373                                                         underflows,
1374                                                         name);
1375                 if (ret != 0)
1376                         goto out_unlock;
1377                 ++j;
1378         }
1379
1380         ret = -EINVAL;
1381         if (j != number) {
1382                 duprintf("translate_compat_table: %u not %u entries\n",
1383                          j, number);
1384                 goto out_unlock;
1385         }
1386
1387         /* Check hooks all assigned */
1388         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1389                 /* Only hooks which are valid */
1390                 if (!(valid_hooks & (1 << i)))
1391                         continue;
1392                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1393                         duprintf("Invalid hook entry %u %u\n",
1394                                  i, hook_entries[i]);
1395                         goto out_unlock;
1396                 }
1397                 if (info->underflow[i] == 0xFFFFFFFF) {
1398                         duprintf("Invalid underflow %u %u\n",
1399                                  i, underflows[i]);
1400                         goto out_unlock;
1401                 }
1402         }
1403
1404         ret = -ENOMEM;
1405         newinfo = xt_alloc_table_info(size);
1406         if (!newinfo)
1407                 goto out_unlock;
1408
1409         newinfo->number = number;
1410         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1411                 newinfo->hook_entry[i] = info->hook_entry[i];
1412                 newinfo->underflow[i] = info->underflow[i];
1413         }
1414         entry1 = newinfo->entries;
1415         pos = entry1;
1416         size = total_size;
1417         xt_entry_foreach(iter0, entry0, total_size) {
1418                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1419                                                   name, newinfo, entry1);
1420                 if (ret != 0)
1421                         break;
1422         }
1423         xt_compat_flush_offsets(NFPROTO_ARP);
1424         xt_compat_unlock(NFPROTO_ARP);
1425         if (ret)
1426                 goto free_newinfo;
1427
1428         ret = -ELOOP;
1429         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1430                 goto free_newinfo;
1431
1432         i = 0;
1433         xt_entry_foreach(iter1, entry1, newinfo->size) {
1434                 iter1->counters.pcnt = xt_percpu_counter_alloc();
1435                 if (IS_ERR_VALUE(iter1->counters.pcnt)) {
1436                         ret = -ENOMEM;
1437                         break;
1438                 }
1439
1440                 ret = check_target(iter1, name);
1441                 if (ret != 0) {
1442                         xt_percpu_counter_free(iter1->counters.pcnt);
1443                         break;
1444                 }
1445                 ++i;
1446                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1447                     XT_ERROR_TARGET) == 0)
1448                         ++newinfo->stacksize;
1449         }
1450         if (ret) {
1451                 /*
1452                  * The first i matches need cleanup_entry (calls ->destroy)
1453                  * because they had called ->check already. The other j-i
1454                  * entries need only release.
1455                  */
1456                 int skip = i;
1457                 j -= i;
1458                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1459                         if (skip-- > 0)
1460                                 continue;
1461                         if (j-- == 0)
1462                                 break;
1463                         compat_release_entry(iter0);
1464                 }
1465                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1466                         if (i-- == 0)
1467                                 break;
1468                         cleanup_entry(iter1);
1469                 }
1470                 xt_free_table_info(newinfo);
1471                 return ret;
1472         }
1473
1474         *pinfo = newinfo;
1475         *pentry0 = entry1;
1476         xt_free_table_info(info);
1477         return 0;
1478
1479 free_newinfo:
1480         xt_free_table_info(newinfo);
1481 out:
1482         xt_entry_foreach(iter0, entry0, total_size) {
1483                 if (j-- == 0)
1484                         break;
1485                 compat_release_entry(iter0);
1486         }
1487         return ret;
1488 out_unlock:
1489         xt_compat_flush_offsets(NFPROTO_ARP);
1490         xt_compat_unlock(NFPROTO_ARP);
1491         goto out;
1492 }
1493
1494 struct compat_arpt_replace {
1495         char                            name[XT_TABLE_MAXNAMELEN];
1496         u32                             valid_hooks;
1497         u32                             num_entries;
1498         u32                             size;
1499         u32                             hook_entry[NF_ARP_NUMHOOKS];
1500         u32                             underflow[NF_ARP_NUMHOOKS];
1501         u32                             num_counters;
1502         compat_uptr_t                   counters;
1503         struct compat_arpt_entry        entries[0];
1504 };
1505
1506 static int compat_do_replace(struct net *net, void __user *user,
1507                              unsigned int len)
1508 {
1509         int ret;
1510         struct compat_arpt_replace tmp;
1511         struct xt_table_info *newinfo;
1512         void *loc_cpu_entry;
1513         struct arpt_entry *iter;
1514
1515         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1516                 return -EFAULT;
1517
1518         /* overflow check */
1519         if (tmp.size >= INT_MAX / num_possible_cpus())
1520                 return -ENOMEM;
1521         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1522                 return -ENOMEM;
1523         if (tmp.num_counters == 0)
1524                 return -EINVAL;
1525
1526         tmp.name[sizeof(tmp.name)-1] = 0;
1527
1528         newinfo = xt_alloc_table_info(tmp.size);
1529         if (!newinfo)
1530                 return -ENOMEM;
1531
1532         loc_cpu_entry = newinfo->entries;
1533         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1534                 ret = -EFAULT;
1535                 goto free_newinfo;
1536         }
1537
1538         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1539                                      &newinfo, &loc_cpu_entry, tmp.size,
1540                                      tmp.num_entries, tmp.hook_entry,
1541                                      tmp.underflow);
1542         if (ret != 0)
1543                 goto free_newinfo;
1544
1545         duprintf("compat_do_replace: Translated table\n");
1546
1547         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1548                            tmp.num_counters, compat_ptr(tmp.counters));
1549         if (ret)
1550                 goto free_newinfo_untrans;
1551         return 0;
1552
1553  free_newinfo_untrans:
1554         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1555                 cleanup_entry(iter);
1556  free_newinfo:
1557         xt_free_table_info(newinfo);
1558         return ret;
1559 }
1560
1561 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1562                                   unsigned int len)
1563 {
1564         int ret;
1565
1566         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1567                 return -EPERM;
1568
1569         switch (cmd) {
1570         case ARPT_SO_SET_REPLACE:
1571                 ret = compat_do_replace(sock_net(sk), user, len);
1572                 break;
1573
1574         case ARPT_SO_SET_ADD_COUNTERS:
1575                 ret = do_add_counters(sock_net(sk), user, len, 1);
1576                 break;
1577
1578         default:
1579                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1580                 ret = -EINVAL;
1581         }
1582
1583         return ret;
1584 }
1585
1586 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1587                                      compat_uint_t *size,
1588                                      struct xt_counters *counters,
1589                                      unsigned int i)
1590 {
1591         struct xt_entry_target *t;
1592         struct compat_arpt_entry __user *ce;
1593         u_int16_t target_offset, next_offset;
1594         compat_uint_t origsize;
1595         int ret;
1596
1597         origsize = *size;
1598         ce = (struct compat_arpt_entry __user *)*dstptr;
1599         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1600             copy_to_user(&ce->counters, &counters[i],
1601             sizeof(counters[i])) != 0)
1602                 return -EFAULT;
1603
1604         *dstptr += sizeof(struct compat_arpt_entry);
1605         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1606
1607         target_offset = e->target_offset - (origsize - *size);
1608
1609         t = arpt_get_target(e);
1610         ret = xt_compat_target_to_user(t, dstptr, size);
1611         if (ret)
1612                 return ret;
1613         next_offset = e->next_offset - (origsize - *size);
1614         if (put_user(target_offset, &ce->target_offset) != 0 ||
1615             put_user(next_offset, &ce->next_offset) != 0)
1616                 return -EFAULT;
1617         return 0;
1618 }
1619
1620 static int compat_copy_entries_to_user(unsigned int total_size,
1621                                        struct xt_table *table,
1622                                        void __user *userptr)
1623 {
1624         struct xt_counters *counters;
1625         const struct xt_table_info *private = table->private;
1626         void __user *pos;
1627         unsigned int size;
1628         int ret = 0;
1629         unsigned int i = 0;
1630         struct arpt_entry *iter;
1631
1632         counters = alloc_counters(table);
1633         if (IS_ERR(counters))
1634                 return PTR_ERR(counters);
1635
1636         pos = userptr;
1637         size = total_size;
1638         xt_entry_foreach(iter, private->entries, total_size) {
1639                 ret = compat_copy_entry_to_user(iter, &pos,
1640                                                 &size, counters, i++);
1641                 if (ret != 0)
1642                         break;
1643         }
1644         vfree(counters);
1645         return ret;
1646 }
1647
1648 struct compat_arpt_get_entries {
1649         char name[XT_TABLE_MAXNAMELEN];
1650         compat_uint_t size;
1651         struct compat_arpt_entry entrytable[0];
1652 };
1653
1654 static int compat_get_entries(struct net *net,
1655                               struct compat_arpt_get_entries __user *uptr,
1656                               int *len)
1657 {
1658         int ret;
1659         struct compat_arpt_get_entries get;
1660         struct xt_table *t;
1661
1662         if (*len < sizeof(get)) {
1663                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1664                 return -EINVAL;
1665         }
1666         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1667                 return -EFAULT;
1668         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1669                 duprintf("compat_get_entries: %u != %zu\n",
1670                          *len, sizeof(get) + get.size);
1671                 return -EINVAL;
1672         }
1673         get.name[sizeof(get.name) - 1] = '\0';
1674
1675         xt_compat_lock(NFPROTO_ARP);
1676         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1677         if (!IS_ERR_OR_NULL(t)) {
1678                 const struct xt_table_info *private = t->private;
1679                 struct xt_table_info info;
1680
1681                 duprintf("t->private->number = %u\n", private->number);
1682                 ret = compat_table_info(private, &info);
1683                 if (!ret && get.size == info.size) {
1684                         ret = compat_copy_entries_to_user(private->size,
1685                                                           t, uptr->entrytable);
1686                 } else if (!ret) {
1687                         duprintf("compat_get_entries: I've got %u not %u!\n",
1688                                  private->size, get.size);
1689                         ret = -EAGAIN;
1690                 }
1691                 xt_compat_flush_offsets(NFPROTO_ARP);
1692                 module_put(t->me);
1693                 xt_table_unlock(t);
1694         } else
1695                 ret = t ? PTR_ERR(t) : -ENOENT;
1696
1697         xt_compat_unlock(NFPROTO_ARP);
1698         return ret;
1699 }
1700
1701 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1702
1703 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1704                                   int *len)
1705 {
1706         int ret;
1707
1708         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1709                 return -EPERM;
1710
1711         switch (cmd) {
1712         case ARPT_SO_GET_INFO:
1713                 ret = get_info(sock_net(sk), user, len, 1);
1714                 break;
1715         case ARPT_SO_GET_ENTRIES:
1716                 ret = compat_get_entries(sock_net(sk), user, len);
1717                 break;
1718         default:
1719                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1720         }
1721         return ret;
1722 }
1723 #endif
1724
1725 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1726 {
1727         int ret;
1728
1729         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1730                 return -EPERM;
1731
1732         switch (cmd) {
1733         case ARPT_SO_SET_REPLACE:
1734                 ret = do_replace(sock_net(sk), user, len);
1735                 break;
1736
1737         case ARPT_SO_SET_ADD_COUNTERS:
1738                 ret = do_add_counters(sock_net(sk), user, len, 0);
1739                 break;
1740
1741         default:
1742                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1743                 ret = -EINVAL;
1744         }
1745
1746         return ret;
1747 }
1748
1749 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1750 {
1751         int ret;
1752
1753         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1754                 return -EPERM;
1755
1756         switch (cmd) {
1757         case ARPT_SO_GET_INFO:
1758                 ret = get_info(sock_net(sk), user, len, 0);
1759                 break;
1760
1761         case ARPT_SO_GET_ENTRIES:
1762                 ret = get_entries(sock_net(sk), user, len);
1763                 break;
1764
1765         case ARPT_SO_GET_REVISION_TARGET: {
1766                 struct xt_get_revision rev;
1767
1768                 if (*len != sizeof(rev)) {
1769                         ret = -EINVAL;
1770                         break;
1771                 }
1772                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1773                         ret = -EFAULT;
1774                         break;
1775                 }
1776                 rev.name[sizeof(rev.name)-1] = 0;
1777
1778                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1779                                                          rev.revision, 1, &ret),
1780                                         "arpt_%s", rev.name);
1781                 break;
1782         }
1783
1784         default:
1785                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1786                 ret = -EINVAL;
1787         }
1788
1789         return ret;
1790 }
1791
1792 static void __arpt_unregister_table(struct xt_table *table)
1793 {
1794         struct xt_table_info *private;
1795         void *loc_cpu_entry;
1796         struct module *table_owner = table->me;
1797         struct arpt_entry *iter;
1798
1799         private = xt_unregister_table(table);
1800
1801         /* Decrease module usage counts and free resources */
1802         loc_cpu_entry = private->entries;
1803         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1804                 cleanup_entry(iter);
1805         if (private->number > private->initial_entries)
1806                 module_put(table_owner);
1807         xt_free_table_info(private);
1808 }
1809
1810 int arpt_register_table(struct net *net,
1811                         const struct xt_table *table,
1812                         const struct arpt_replace *repl,
1813                         const struct nf_hook_ops *ops,
1814                         struct xt_table **res)
1815 {
1816         int ret;
1817         struct xt_table_info *newinfo;
1818         struct xt_table_info bootstrap = {0};
1819         void *loc_cpu_entry;
1820         struct xt_table *new_table;
1821
1822         newinfo = xt_alloc_table_info(repl->size);
1823         if (!newinfo)
1824                 return -ENOMEM;
1825
1826         loc_cpu_entry = newinfo->entries;
1827         memcpy(loc_cpu_entry, repl->entries, repl->size);
1828
1829         ret = translate_table(newinfo, loc_cpu_entry, repl);
1830         duprintf("arpt_register_table: translate table gives %d\n", ret);
1831         if (ret != 0)
1832                 goto out_free;
1833
1834         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1835         if (IS_ERR(new_table)) {
1836                 ret = PTR_ERR(new_table);
1837                 goto out_free;
1838         }
1839
1840         /* set res now, will see skbs right after nf_register_net_hooks */
1841         WRITE_ONCE(*res, new_table);
1842
1843         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1844         if (ret != 0) {
1845                 __arpt_unregister_table(new_table);
1846                 *res = NULL;
1847         }
1848
1849         return ret;
1850
1851 out_free:
1852         xt_free_table_info(newinfo);
1853         return ret;
1854 }
1855
1856 void arpt_unregister_table(struct net *net, struct xt_table *table,
1857                            const struct nf_hook_ops *ops)
1858 {
1859         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1860         __arpt_unregister_table(table);
1861 }
1862
1863 /* The built-in targets: standard (NULL) and error. */
1864 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1865         {
1866                 .name             = XT_STANDARD_TARGET,
1867                 .targetsize       = sizeof(int),
1868                 .family           = NFPROTO_ARP,
1869 #ifdef CONFIG_COMPAT
1870                 .compatsize       = sizeof(compat_int_t),
1871                 .compat_from_user = compat_standard_from_user,
1872                 .compat_to_user   = compat_standard_to_user,
1873 #endif
1874         },
1875         {
1876                 .name             = XT_ERROR_TARGET,
1877                 .target           = arpt_error,
1878                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1879                 .family           = NFPROTO_ARP,
1880         },
1881 };
1882
1883 static struct nf_sockopt_ops arpt_sockopts = {
1884         .pf             = PF_INET,
1885         .set_optmin     = ARPT_BASE_CTL,
1886         .set_optmax     = ARPT_SO_SET_MAX+1,
1887         .set            = do_arpt_set_ctl,
1888 #ifdef CONFIG_COMPAT
1889         .compat_set     = compat_do_arpt_set_ctl,
1890 #endif
1891         .get_optmin     = ARPT_BASE_CTL,
1892         .get_optmax     = ARPT_SO_GET_MAX+1,
1893         .get            = do_arpt_get_ctl,
1894 #ifdef CONFIG_COMPAT
1895         .compat_get     = compat_do_arpt_get_ctl,
1896 #endif
1897         .owner          = THIS_MODULE,
1898 };
1899
1900 static int __net_init arp_tables_net_init(struct net *net)
1901 {
1902         return xt_proto_init(net, NFPROTO_ARP);
1903 }
1904
1905 static void __net_exit arp_tables_net_exit(struct net *net)
1906 {
1907         xt_proto_fini(net, NFPROTO_ARP);
1908 }
1909
1910 static struct pernet_operations arp_tables_net_ops = {
1911         .init = arp_tables_net_init,
1912         .exit = arp_tables_net_exit,
1913 };
1914
1915 static int __init arp_tables_init(void)
1916 {
1917         int ret;
1918
1919         ret = register_pernet_subsys(&arp_tables_net_ops);
1920         if (ret < 0)
1921                 goto err1;
1922
1923         /* No one else will be downing sem now, so we won't sleep */
1924         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1925         if (ret < 0)
1926                 goto err2;
1927
1928         /* Register setsockopt */
1929         ret = nf_register_sockopt(&arpt_sockopts);
1930         if (ret < 0)
1931                 goto err4;
1932
1933         pr_info("arp_tables: (C) 2002 David S. Miller\n");
1934         return 0;
1935
1936 err4:
1937         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1938 err2:
1939         unregister_pernet_subsys(&arp_tables_net_ops);
1940 err1:
1941         return ret;
1942 }
1943
1944 static void __exit arp_tables_fini(void)
1945 {
1946         nf_unregister_sockopt(&arpt_sockopts);
1947         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1948         unregister_pernet_subsys(&arp_tables_net_ops);
1949 }
1950
1951 EXPORT_SYMBOL(arpt_register_table);
1952 EXPORT_SYMBOL(arpt_unregister_table);
1953 EXPORT_SYMBOL(arpt_do_table);
1954
1955 module_init(arp_tables_init);
1956 module_exit(arp_tables_fini);