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 net_device *in,
 252                            const struct net_device *out,
 253                            struct xt_table *table)
 254 {
 255         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 256         unsigned int verdict = NF_DROP;
 257         const struct arphdr *arp;
 258         struct arpt_entry *e, *back;
 259         const char *indev, *outdev;
 260         void *table_base;
 261         const struct xt_table_info *private;
 262         struct xt_action_param acpar;
 263         unsigned int addend;
 264
 265         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 266                 return NF_DROP;
 267
 268         indev = in ? in->name : nulldevname;
 269         outdev = out ? out->name : nulldevname;
 270
 271         local_bh_disable();
 272         addend = xt_write_recseq_begin();
 273         private = table->private;
 274         /*
 275          * Ensure we load private-> members after we've fetched the base
 276          * pointer.
 277          */
 278         smp_read_barrier_depends();
 279         table_base = private->entries[smp_processor_id()];
 280
 281         e = get_entry(table_base, private->hook_entry[hook]);
 282         back = get_entry(table_base, private->underflow[hook]);
 283
 284         acpar.in      = in;
 285         acpar.out     = out;
 286         acpar.hooknum = hook;
 287         acpar.family  = NFPROTO_ARP;
 288         acpar.hotdrop = false;
 289
 290         arp = arp_hdr(skb);
 291         do {
 292                 const struct xt_entry_target *t;
 293
 294                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 295                         e = arpt_next_entry(e);
 296                         continue;
 297                 }
 298
 299                 ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
 300
 301                 t = arpt_get_target_c(e);
 302
 303                 /* Standard target? */
 304                 if (!t->u.kernel.target->target) {
 305                         int v;
 306
 307                         v = ((struct xt_standard_target *)t)->verdict;
 308                         if (v < 0) {
 309                                 /* Pop from stack? */
 310                                 if (v != XT_RETURN) {
 311                                         verdict = (unsigned int)(-v) - 1;
 312                                         break;
 313                                 }
 314                                 e = back;
 315                                 back = get_entry(table_base, back->comefrom);
 316                                 continue;
 317                         }
 318                         if (table_base + v
 319                             != arpt_next_entry(e)) {
 320                                 /* Save old back ptr in next entry */
 321                                 struct arpt_entry *next = arpt_next_entry(e);
 322                                 next->comefrom = (void *)back - table_base;
 323
 324                                 /* set back pointer to next entry */
 325                                 back = next;
 326                         }
 327
 328                         e = get_entry(table_base, v);
 329                         continue;
 330                 }
 331
 332                 /* Targets which reenter must return
 333                  * abs. verdicts
 334                  */
 335                 acpar.target   = t->u.kernel.target;
 336                 acpar.targinfo = t->data;
 337                 verdict = t->u.kernel.target->target(skb, &acpar);
 338
 339                 /* Target might have changed stuff. */
 340                 arp = arp_hdr(skb);
 341
 342                 if (verdict == XT_CONTINUE)
 343                         e = arpt_next_entry(e);
 344                 else
 345                         /* Verdict */
 346                         break;
 347         } while (!acpar.hotdrop);
 348         xt_write_recseq_end(addend);
 349         local_bh_enable();
 350
 351         if (acpar.hotdrop)
 352                 return NF_DROP;
 353         else
 354                 return verdict;
 355 }
 356
 357 /* All zeroes == unconditional rule. */
 358 static inline bool unconditional(const struct arpt_arp *arp)
 359 {
 360         static const struct arpt_arp uncond;
 361
 362         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 363 }
 364
 365 /* Figures out from what hook each rule can be called: returns 0 if
 366  * there are loops.  Puts hook bitmask in comefrom.
 367  */
 368 static int mark_source_chains(const struct xt_table_info *newinfo,
 369                               unsigned int valid_hooks, void *entry0)
 370 {
 371         unsigned int hook;
 372
 373         /* No recursion; use packet counter to save back ptrs (reset
 374          * to 0 as we leave), and comefrom to save source hook bitmask.
 375          */
 376         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 377                 unsigned int pos = newinfo->hook_entry[hook];
 378                 struct arpt_entry *e
 379                         = (struct arpt_entry *)(entry0 + pos);
 380
 381                 if (!(valid_hooks & (1 << hook)))
 382                         continue;
 383
 384                 /* Set initial back pointer. */
 385                 e->counters.pcnt = pos;
 386
 387                 for (;;) {
 388                         const struct xt_standard_target *t
 389                                 = (void *)arpt_get_target_c(e);
 390                         int visited = e->comefrom & (1 << hook);
 391
 392                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 393                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 394                                        hook, pos, e->comefrom);
 395                                 return 0;
 396                         }
 397                         e->comefrom
 398                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 399
 400                         /* Unconditional return/END. */
 401                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 402                              (strcmp(t->target.u.user.name,
 403                                      XT_STANDARD_TARGET) == 0) &&
 404                              t->verdict < 0 && unconditional(&e->arp)) ||
 405                             visited) {
 406                                 unsigned int oldpos, size;
 407
 408                                 if ((strcmp(t->target.u.user.name,
 409                                             XT_STANDARD_TARGET) == 0) &&
 410                                     t->verdict < -NF_MAX_VERDICT - 1) {
 411                                         duprintf("mark_source_chains: bad "
 412                                                 "negative verdict (%i)\n",
 413                                                                 t->verdict);
 414                                         return 0;
 415                                 }
 416
 417                                 /* Return: backtrack through the last
 418                                  * big jump.
 419                                  */
 420                                 do {
 421                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 422                                         oldpos = pos;
 423                                         pos = e->counters.pcnt;
 424                                         e->counters.pcnt = 0;
 425
 426                                         /* We're at the start. */
 427                                         if (pos == oldpos)
 428                                                 goto next;
 429
 430                                         e = (struct arpt_entry *)
 431                                                 (entry0 + pos);
 432                                 } while (oldpos == pos + e->next_offset);
 433
 434                                 /* Move along one */
 435                                 size = e->next_offset;
 436                                 e = (struct arpt_entry *)
 437                                         (entry0 + pos + size);
 438                                 e->counters.pcnt = pos;
 439                                 pos += size;
 440                         } else {
 441                                 int newpos = t->verdict;
 442
 443                                 if (strcmp(t->target.u.user.name,
 444                                            XT_STANDARD_TARGET) == 0 &&
 445                                     newpos >= 0) {
 446                                         if (newpos > newinfo->size -
 447                                                 sizeof(struct arpt_entry)) {
 448                                                 duprintf("mark_source_chains: "
 449                                                         "bad verdict (%i)\n",
 450                                                                 newpos);
 451                                                 return 0;
 452                                         }
 453
 454                                         /* This a jump; chase it. */
 455                                         duprintf("Jump rule %u -> %u\n",
 456                                                  pos, newpos);
 457                                 } else {
 458                                         /* ... this is a fallthru */
 459                                         newpos = pos + e->next_offset;
 460                                 }
 461                                 e = (struct arpt_entry *)
 462                                         (entry0 + newpos);
 463                                 e->counters.pcnt = pos;
 464                                 pos = newpos;
 465                         }
 466                 }
 467                 next:
 468                 duprintf("Finished chain %u\n", hook);
 469         }
 470         return 1;
 471 }
 472
 473 static inline int check_entry(const struct arpt_entry *e, const char *name)
 474 {
 475         const struct xt_entry_target *t;
 476
 477         if (!arp_checkentry(&e->arp)) {
 478                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 479                 return -EINVAL;
 480         }
 481
 482         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
 483                 return -EINVAL;
 484
 485         t = arpt_get_target_c(e);
 486         if (e->target_offset + t->u.target_size > e->next_offset)
 487                 return -EINVAL;
 488
 489         return 0;
 490 }
 491
 492 static inline int check_target(struct arpt_entry *e, const char *name)
 493 {
 494         struct xt_entry_target *t = arpt_get_target(e);
 495         int ret;
 496         struct xt_tgchk_param par = {
 497                 .table     = name,
 498                 .entryinfo = e,
 499                 .target    = t->u.kernel.target,
 500                 .targinfo  = t->data,
 501                 .hook_mask = e->comefrom,
 502                 .family    = NFPROTO_ARP,
 503         };
 504
 505         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 506         if (ret < 0) {
 507                 duprintf("arp_tables: check failed for `%s'.\n",
 508                          t->u.kernel.target->name);
 509                 return ret;
 510         }
 511         return 0;
 512 }
 513
 514 static inline int
 515 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 516 {
 517         struct xt_entry_target *t;
 518         struct xt_target *target;
 519         int ret;
 520
 521         ret = check_entry(e, name);
 522         if (ret)
 523                 return ret;
 524
 525         t = arpt_get_target(e);
 526         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 527                                         t->u.user.revision);
 528         if (IS_ERR(target)) {
 529                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 530                 ret = PTR_ERR(target);
 531                 goto out;
 532         }
 533         t->u.kernel.target = target;
 534
 535         ret = check_target(e, name);
 536         if (ret)
 537                 goto err;
 538         return 0;
 539 err:
 540         module_put(t->u.kernel.target->me);
 541 out:
 542         return ret;
 543 }
 544
 545 static bool check_underflow(const struct arpt_entry *e)
 546 {
 547         const struct xt_entry_target *t;
 548         unsigned int verdict;
 549
 550         if (!unconditional(&e->arp))
 551                 return false;
 552         t = arpt_get_target_c(e);
 553         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 554                 return false;
 555         verdict = ((struct xt_standard_target *)t)->verdict;
 556         verdict = -verdict - 1;
 557         return verdict == NF_DROP || verdict == NF_ACCEPT;
 558 }
 559
 560 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 561                                              struct xt_table_info *newinfo,
 562                                              const unsigned char *base,
 563                                              const unsigned char *limit,
 564                                              const unsigned int *hook_entries,
 565                                              const unsigned int *underflows,
 566                                              unsigned int valid_hooks)
 567 {
 568         unsigned int h;
 569
 570         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 571             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 572                 duprintf("Bad offset %p\n", e);
 573                 return -EINVAL;
 574         }
 575
 576         if (e->next_offset
 577             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 578                 duprintf("checking: element %p size %u\n",
 579                          e, e->next_offset);
 580                 return -EINVAL;
 581         }
 582
 583         /* Check hooks & underflows */
 584         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 585                 if (!(valid_hooks & (1 << h)))
 586                         continue;
 587                 if ((unsigned char *)e - base == hook_entries[h])
 588                         newinfo->hook_entry[h] = hook_entries[h];
 589                 if ((unsigned char *)e - base == underflows[h]) {
 590                         if (!check_underflow(e)) {
 591                                 pr_err("Underflows must be unconditional and "
 592                                        "use the STANDARD target with "
 593                                        "ACCEPT/DROP\n");
 594                                 return -EINVAL;
 595                         }
 596                         newinfo->underflow[h] = underflows[h];
 597                 }
 598         }
 599
 600         /* Clear counters and comefrom */
 601         e->counters = ((struct xt_counters) { 0, 0 });
 602         e->comefrom = 0;
 603         return 0;
 604 }
 605
 606 static inline void cleanup_entry(struct arpt_entry *e)
 607 {
 608         struct xt_tgdtor_param par;
 609         struct xt_entry_target *t;
 610
 611         t = arpt_get_target(e);
 612         par.target   = t->u.kernel.target;
 613         par.targinfo = t->data;
 614         par.family   = NFPROTO_ARP;
 615         if (par.target->destroy != NULL)
 616                 par.target->destroy(&par);
 617         module_put(par.target->me);
 618 }
 619
 620 /* Checks and translates the user-supplied table segment (held in
 621  * newinfo).
 622  */
 623 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 624                            const struct arpt_replace *repl)
 625 {
 626         struct arpt_entry *iter;
 627         unsigned int i;
 628         int ret = 0;
 629
 630         newinfo->size = repl->size;
 631         newinfo->number = repl->num_entries;
 632
 633         /* Init all hooks to impossible value. */
 634         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 635                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 636                 newinfo->underflow[i] = 0xFFFFFFFF;
 637         }
 638
 639         duprintf("translate_table: size %u\n", newinfo->size);
 640         i = 0;
 641
 642         /* Walk through entries, checking offsets. */
 643         xt_entry_foreach(iter, entry0, newinfo->size) {
 644                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 645                                                  entry0 + repl->size,
 646                                                  repl->hook_entry,
 647                                                  repl->underflow,
 648                                                  repl->valid_hooks);
 649                 if (ret != 0)
 650                         break;
 651                 ++i;
 652                 if (strcmp(arpt_get_target(iter)->u.user.name,
 653                     XT_ERROR_TARGET) == 0)
 654                         ++newinfo->stacksize;
 655         }
 656         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 657         if (ret != 0)
 658                 return ret;
 659
 660         if (i != repl->num_entries) {
 661                 duprintf("translate_table: %u not %u entries\n",
 662                          i, repl->num_entries);
 663                 return -EINVAL;
 664         }
 665
 666         /* Check hooks all assigned */
 667         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 668                 /* Only hooks which are valid */
 669                 if (!(repl->valid_hooks & (1 << i)))
 670                         continue;
 671                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 672                         duprintf("Invalid hook entry %u %u\n",
 673                                  i, repl->hook_entry[i]);
 674                         return -EINVAL;
 675                 }
 676                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 677                         duprintf("Invalid underflow %u %u\n",
 678                                  i, repl->underflow[i]);
 679                         return -EINVAL;
 680                 }
 681         }
 682
 683         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 684                 duprintf("Looping hook\n");
 685                 return -ELOOP;
 686         }
 687
 688         /* Finally, each sanity check must pass */
 689         i = 0;
 690         xt_entry_foreach(iter, entry0, newinfo->size) {
 691                 ret = find_check_entry(iter, repl->name, repl->size);
 692                 if (ret != 0)
 693                         break;
 694                 ++i;
 695         }
 696
 697         if (ret != 0) {
 698                 xt_entry_foreach(iter, entry0, newinfo->size) {
 699                         if (i-- == 0)
 700                                 break;
 701                         cleanup_entry(iter);
 702                 }
 703                 return ret;
 704         }
 705
 706         /* And one copy for every other CPU */
 707         for_each_possible_cpu(i) {
 708                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 709                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 710         }
 711
 712         return ret;
 713 }
 714
 715 static void get_counters(const struct xt_table_info *t,
 716                          struct xt_counters counters[])
 717 {
 718         struct arpt_entry *iter;
 719         unsigned int cpu;
 720         unsigned int i;
 721
 722         for_each_possible_cpu(cpu) {
 723                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 724
 725                 i = 0;
 726                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 727                         u64 bcnt, pcnt;
 728                         unsigned int start;
 729
 730                         do {
 731                                 start = read_seqcount_begin(s);
 732                                 bcnt = iter->counters.bcnt;
 733                                 pcnt = iter->counters.pcnt;
 734                         } while (read_seqcount_retry(s, start));
 735
 736                         ADD_COUNTER(counters[i], bcnt, pcnt);
 737                         ++i;
 738                 }
 739         }
 740 }
 741
 742 static struct xt_counters *alloc_counters(const struct xt_table *table)
 743 {
 744         unsigned int countersize;
 745         struct xt_counters *counters;
 746         const struct xt_table_info *private = table->private;
 747
 748         /* We need atomic snapshot of counters: rest doesn't change
 749          * (other than comefrom, which userspace doesn't care
 750          * about).
 751          */
 752         countersize = sizeof(struct xt_counters) * private->number;
 753         counters = vzalloc(countersize);
 754
 755         if (counters == NULL)
 756                 return ERR_PTR(-ENOMEM);
 757
 758         get_counters(private, counters);
 759
 760         return counters;
 761 }
 762
 763 static int copy_entries_to_user(unsigned int total_size,
 764                                 const struct xt_table *table,
 765                                 void __user *userptr)
 766 {
 767         unsigned int off, num;
 768         const struct arpt_entry *e;
 769         struct xt_counters *counters;
 770         struct xt_table_info *private = table->private;
 771         int ret = 0;
 772         void *loc_cpu_entry;
 773
 774         counters = alloc_counters(table);
 775         if (IS_ERR(counters))
 776                 return PTR_ERR(counters);
 777
 778         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 779         /* ... then copy entire thing ... */
 780         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 781                 ret = -EFAULT;
 782                 goto free_counters;
 783         }
 784
 785         /* FIXME: use iterator macros --RR */
 786         /* ... then go back and fix counters and names */
 787         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 788                 const struct xt_entry_target *t;
 789
 790                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 791                 if (copy_to_user(userptr + off
 792                                  + offsetof(struct arpt_entry, counters),
 793                                  &counters[num],
 794                                  sizeof(counters[num])) != 0) {
 795                         ret = -EFAULT;
 796                         goto free_counters;
 797                 }
 798
 799                 t = arpt_get_target_c(e);
 800                 if (copy_to_user(userptr + off + e->target_offset
 801                                  + offsetof(struct xt_entry_target,
 802                                             u.user.name),
 803                                  t->u.kernel.target->name,
 804                                  strlen(t->u.kernel.target->name)+1) != 0) {
 805                         ret = -EFAULT;
 806                         goto free_counters;
 807                 }
 808         }
 809
 810  free_counters:
 811         vfree(counters);
 812         return ret;
 813 }
 814
 815 #ifdef CONFIG_COMPAT
 816 static void compat_standard_from_user(void *dst, const void *src)
 817 {
 818         int v = *(compat_int_t *)src;
 819
 820         if (v > 0)
 821                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 822         memcpy(dst, &v, sizeof(v));
 823 }
 824
 825 static int compat_standard_to_user(void __user *dst, const void *src)
 826 {
 827         compat_int_t cv = *(int *)src;
 828
 829         if (cv > 0)
 830                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 831         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 832 }
 833
 834 static int compat_calc_entry(const struct arpt_entry *e,
 835                              const struct xt_table_info *info,
 836                              const void *base, struct xt_table_info *newinfo)
 837 {
 838         const struct xt_entry_target *t;
 839         unsigned int entry_offset;
 840         int off, i, ret;
 841
 842         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 843         entry_offset = (void *)e - base;
 844
 845         t = arpt_get_target_c(e);
 846         off += xt_compat_target_offset(t->u.kernel.target);
 847         newinfo->size -= off;
 848         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 849         if (ret)
 850                 return ret;
 851
 852         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 853                 if (info->hook_entry[i] &&
 854                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 855                         newinfo->hook_entry[i] -= off;
 856                 if (info->underflow[i] &&
 857                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 858                         newinfo->underflow[i] -= off;
 859         }
 860         return 0;
 861 }
 862
 863 static int compat_table_info(const struct xt_table_info *info,
 864                              struct xt_table_info *newinfo)
 865 {
 866         struct arpt_entry *iter;
 867         void *loc_cpu_entry;
 868         int ret;
 869
 870         if (!newinfo || !info)
 871                 return -EINVAL;
 872
 873         /* we dont care about newinfo->entries[] */
 874         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 875         newinfo->initial_entries = 0;
 876         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 877         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 878         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 879                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 880                 if (ret != 0)
 881                         return ret;
 882         }
 883         return 0;
 884 }
 885 #endif
 886
 887 static int get_info(struct net *net, void __user *user,
 888                     const int *len, int compat)
 889 {
 890         char name[XT_TABLE_MAXNAMELEN];
 891         struct xt_table *t;
 892         int ret;
 893
 894         if (*len != sizeof(struct arpt_getinfo)) {
 895                 duprintf("length %u != %Zu\n", *len,
 896                          sizeof(struct arpt_getinfo));
 897                 return -EINVAL;
 898         }
 899
 900         if (copy_from_user(name, user, sizeof(name)) != 0)
 901                 return -EFAULT;
 902
 903         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 904 #ifdef CONFIG_COMPAT
 905         if (compat)
 906                 xt_compat_lock(NFPROTO_ARP);
 907 #endif
 908         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 909                                     "arptable_%s", name);
 910         if (!IS_ERR_OR_NULL(t)) {
 911                 struct arpt_getinfo info;
 912                 const struct xt_table_info *private = t->private;
 913 #ifdef CONFIG_COMPAT
 914                 struct xt_table_info tmp;
 915
 916                 if (compat) {
 917                         ret = compat_table_info(private, &tmp);
 918                         xt_compat_flush_offsets(NFPROTO_ARP);
 919                         private = &tmp;
 920                 }
 921 #endif
 922                 memset(&info, 0, sizeof(info));
 923                 info.valid_hooks = t->valid_hooks;
 924                 memcpy(info.hook_entry, private->hook_entry,
 925                        sizeof(info.hook_entry));
 926                 memcpy(info.underflow, private->underflow,
 927                        sizeof(info.underflow));
 928                 info.num_entries = private->number;
 929                 info.size = private->size;
 930                 strcpy(info.name, name);
 931
 932                 if (copy_to_user(user, &info, *len) != 0)
 933                         ret = -EFAULT;
 934                 else
 935                         ret = 0;
 936                 xt_table_unlock(t);
 937                 module_put(t->me);
 938         } else
 939                 ret = t ? PTR_ERR(t) : -ENOENT;
 940 #ifdef CONFIG_COMPAT
 941         if (compat)
 942                 xt_compat_unlock(NFPROTO_ARP);
 943 #endif
 944         return ret;
 945 }
 946
 947 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 948                        const int *len)
 949 {
 950         int ret;
 951         struct arpt_get_entries get;
 952         struct xt_table *t;
 953
 954         if (*len < sizeof(get)) {
 955                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 956                 return -EINVAL;
 957         }
 958         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 959                 return -EFAULT;
 960         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 961                 duprintf("get_entries: %u != %Zu\n", *len,
 962                          sizeof(struct arpt_get_entries) + get.size);
 963                 return -EINVAL;
 964         }
 965
 966         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 967         if (!IS_ERR_OR_NULL(t)) {
 968                 const struct xt_table_info *private = t->private;
 969
 970                 duprintf("t->private->number = %u\n",
 971                          private->number);
 972                 if (get.size == private->size)
 973                         ret = copy_entries_to_user(private->size,
 974                                                    t, uptr->entrytable);
 975                 else {
 976                         duprintf("get_entries: I've got %u not %u!\n",
 977                                  private->size, get.size);
 978                         ret = -EAGAIN;
 979                 }
 980                 module_put(t->me);
 981                 xt_table_unlock(t);
 982         } else
 983                 ret = t ? PTR_ERR(t) : -ENOENT;
 984
 985         return ret;
 986 }
 987
 988 static int __do_replace(struct net *net, const char *name,
 989                         unsigned int valid_hooks,
 990                         struct xt_table_info *newinfo,
 991                         unsigned int num_counters,
 992                         void __user *counters_ptr)
 993 {
 994         int ret;
 995         struct xt_table *t;
 996         struct xt_table_info *oldinfo;
 997         struct xt_counters *counters;
 998         void *loc_cpu_old_entry;
 999         struct arpt_entry *iter;
1000
1001         ret = 0;
1002         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1003         if (!counters) {
1004                 ret = -ENOMEM;
1005                 goto out;
1006         }
1007
1008         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1009                                     "arptable_%s", name);
1010         if (IS_ERR_OR_NULL(t)) {
1011                 ret = t ? PTR_ERR(t) : -ENOENT;
1012                 goto free_newinfo_counters_untrans;
1013         }
1014
1015         /* You lied! */
1016         if (valid_hooks != t->valid_hooks) {
1017                 duprintf("Valid hook crap: %08X vs %08X\n",
1018                          valid_hooks, t->valid_hooks);
1019                 ret = -EINVAL;
1020                 goto put_module;
1021         }
1022
1023         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1024         if (!oldinfo)
1025                 goto put_module;
1026
1027         /* Update module usage count based on number of rules */
1028         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1029                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1030         if ((oldinfo->number > oldinfo->initial_entries) ||
1031             (newinfo->number <= oldinfo->initial_entries))
1032                 module_put(t->me);
1033         if ((oldinfo->number > oldinfo->initial_entries) &&
1034             (newinfo->number <= oldinfo->initial_entries))
1035                 module_put(t->me);
1036
1037         /* Get the old counters, and synchronize with replace */
1038         get_counters(oldinfo, counters);
1039
1040         /* Decrease module usage counts and free resource */
1041         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1042         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1043                 cleanup_entry(iter);
1044
1045         xt_free_table_info(oldinfo);
1046         if (copy_to_user(counters_ptr, counters,
1047                          sizeof(struct xt_counters) * num_counters) != 0) {
1048                 /* Silent error, can't fail, new table is already in place */
1049                 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1050         }
1051         vfree(counters);
1052         xt_table_unlock(t);
1053         return ret;
1054
1055  put_module:
1056         module_put(t->me);
1057         xt_table_unlock(t);
1058  free_newinfo_counters_untrans:
1059         vfree(counters);
1060  out:
1061         return ret;
1062 }
1063
1064 static int do_replace(struct net *net, const void __user *user,
1065                       unsigned int len)
1066 {
1067         int ret;
1068         struct arpt_replace tmp;
1069         struct xt_table_info *newinfo;
1070         void *loc_cpu_entry;
1071         struct arpt_entry *iter;
1072
1073         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1074                 return -EFAULT;
1075
1076         /* overflow check */
1077         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1078                 return -ENOMEM;
1079         tmp.name[sizeof(tmp.name)-1] = 0;
1080
1081         newinfo = xt_alloc_table_info(tmp.size);
1082         if (!newinfo)
1083                 return -ENOMEM;
1084
1085         /* choose the copy that is on our node/cpu */
1086         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1087         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1088                            tmp.size) != 0) {
1089                 ret = -EFAULT;
1090                 goto free_newinfo;
1091         }
1092
1093         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1094         if (ret != 0)
1095                 goto free_newinfo;
1096
1097         duprintf("arp_tables: Translated table\n");
1098
1099         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1100                            tmp.num_counters, tmp.counters);
1101         if (ret)
1102                 goto free_newinfo_untrans;
1103         return 0;
1104
1105  free_newinfo_untrans:
1106         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1107                 cleanup_entry(iter);
1108  free_newinfo:
1109         xt_free_table_info(newinfo);
1110         return ret;
1111 }
1112
1113 static int do_add_counters(struct net *net, const void __user *user,
1114                            unsigned int len, int compat)
1115 {
1116         unsigned int i, curcpu;
1117         struct xt_counters_info tmp;
1118         struct xt_counters *paddc;
1119         unsigned int num_counters;
1120         const char *name;
1121         int size;
1122         void *ptmp;
1123         struct xt_table *t;
1124         const struct xt_table_info *private;
1125         int ret = 0;
1126         void *loc_cpu_entry;
1127         struct arpt_entry *iter;
1128         unsigned int addend;
1129 #ifdef CONFIG_COMPAT
1130         struct compat_xt_counters_info compat_tmp;
1131
1132         if (compat) {
1133                 ptmp = &compat_tmp;
1134                 size = sizeof(struct compat_xt_counters_info);
1135         } else
1136 #endif
1137         {
1138                 ptmp = &tmp;
1139                 size = sizeof(struct xt_counters_info);
1140         }
1141
1142         if (copy_from_user(ptmp, user, size) != 0)
1143                 return -EFAULT;
1144
1145 #ifdef CONFIG_COMPAT
1146         if (compat) {
1147                 num_counters = compat_tmp.num_counters;
1148                 name = compat_tmp.name;
1149         } else
1150 #endif
1151         {
1152                 num_counters = tmp.num_counters;
1153                 name = tmp.name;
1154         }
1155
1156         if (len != size + num_counters * sizeof(struct xt_counters))
1157                 return -EINVAL;
1158
1159         paddc = vmalloc(len - size);
1160         if (!paddc)
1161                 return -ENOMEM;
1162
1163         if (copy_from_user(paddc, user + size, len - size) != 0) {
1164                 ret = -EFAULT;
1165                 goto free;
1166         }
1167
1168         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1169         if (IS_ERR_OR_NULL(t)) {
1170                 ret = t ? PTR_ERR(t) : -ENOENT;
1171                 goto free;
1172         }
1173
1174         local_bh_disable();
1175         private = t->private;
1176         if (private->number != num_counters) {
1177                 ret = -EINVAL;
1178                 goto unlock_up_free;
1179         }
1180
1181         i = 0;
1182         /* Choose the copy that is on our node */
1183         curcpu = smp_processor_id();
1184         loc_cpu_entry = private->entries[curcpu];
1185         addend = xt_write_recseq_begin();
1186         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1187                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1188                 ++i;
1189         }
1190         xt_write_recseq_end(addend);
1191  unlock_up_free:
1192         local_bh_enable();
1193         xt_table_unlock(t);
1194         module_put(t->me);
1195  free:
1196         vfree(paddc);
1197
1198         return ret;
1199 }
1200
1201 #ifdef CONFIG_COMPAT
1202 static inline void compat_release_entry(struct compat_arpt_entry *e)
1203 {
1204         struct xt_entry_target *t;
1205
1206         t = compat_arpt_get_target(e);
1207         module_put(t->u.kernel.target->me);
1208 }
1209
1210 static inline int
1211 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1212                                   struct xt_table_info *newinfo,
1213                                   unsigned int *size,
1214                                   const unsigned char *base,
1215                                   const unsigned char *limit,
1216                                   const unsigned int *hook_entries,
1217                                   const unsigned int *underflows,
1218                                   const char *name)
1219 {
1220         struct xt_entry_target *t;
1221         struct xt_target *target;
1222         unsigned int entry_offset;
1223         int ret, off, h;
1224
1225         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1226         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1227             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1228                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1229                 return -EINVAL;
1230         }
1231
1232         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1233                              sizeof(struct compat_xt_entry_target)) {
1234                 duprintf("checking: element %p size %u\n",
1235                          e, e->next_offset);
1236                 return -EINVAL;
1237         }
1238
1239         /* For purposes of check_entry casting the compat entry is fine */
1240         ret = check_entry((struct arpt_entry *)e, name);
1241         if (ret)
1242                 return ret;
1243
1244         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1245         entry_offset = (void *)e - (void *)base;
1246
1247         t = compat_arpt_get_target(e);
1248         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1249                                         t->u.user.revision);
1250         if (IS_ERR(target)) {
1251                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1252                          t->u.user.name);
1253                 ret = PTR_ERR(target);
1254                 goto out;
1255         }
1256         t->u.kernel.target = target;
1257
1258         off += xt_compat_target_offset(target);
1259         *size += off;
1260         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1261         if (ret)
1262                 goto release_target;
1263
1264         /* Check hooks & underflows */
1265         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1266                 if ((unsigned char *)e - base == hook_entries[h])
1267                         newinfo->hook_entry[h] = hook_entries[h];
1268                 if ((unsigned char *)e - base == underflows[h])
1269                         newinfo->underflow[h] = underflows[h];
1270         }
1271
1272         /* Clear counters and comefrom */
1273         memset(&e->counters, 0, sizeof(e->counters));
1274         e->comefrom = 0;
1275         return 0;
1276
1277 release_target:
1278         module_put(t->u.kernel.target->me);
1279 out:
1280         return ret;
1281 }
1282
1283 static int
1284 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1285                             unsigned int *size, const char *name,
1286                             struct xt_table_info *newinfo, unsigned char *base)
1287 {
1288         struct xt_entry_target *t;
1289         struct xt_target *target;
1290         struct arpt_entry *de;
1291         unsigned int origsize;
1292         int ret, h;
1293
1294         ret = 0;
1295         origsize = *size;
1296         de = (struct arpt_entry *)*dstptr;
1297         memcpy(de, e, sizeof(struct arpt_entry));
1298         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1299
1300         *dstptr += sizeof(struct arpt_entry);
1301         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1302
1303         de->target_offset = e->target_offset - (origsize - *size);
1304         t = compat_arpt_get_target(e);
1305         target = t->u.kernel.target;
1306         xt_compat_target_from_user(t, dstptr, size);
1307
1308         de->next_offset = e->next_offset - (origsize - *size);
1309         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1310                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1311                         newinfo->hook_entry[h] -= origsize - *size;
1312                 if ((unsigned char *)de - base < newinfo->underflow[h])
1313                         newinfo->underflow[h] -= origsize - *size;
1314         }
1315         return ret;
1316 }
1317
1318 static int translate_compat_table(const char *name,
1319                                   unsigned int valid_hooks,
1320                                   struct xt_table_info **pinfo,
1321                                   void **pentry0,
1322                                   unsigned int total_size,
1323                                   unsigned int number,
1324                                   unsigned int *hook_entries,
1325                                   unsigned int *underflows)
1326 {
1327         unsigned int i, j;
1328         struct xt_table_info *newinfo, *info;
1329         void *pos, *entry0, *entry1;
1330         struct compat_arpt_entry *iter0;
1331         struct arpt_entry *iter1;
1332         unsigned int size;
1333         int ret = 0;
1334
1335         info = *pinfo;
1336         entry0 = *pentry0;
1337         size = total_size;
1338         info->number = number;
1339
1340         /* Init all hooks to impossible value. */
1341         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1342                 info->hook_entry[i] = 0xFFFFFFFF;
1343                 info->underflow[i] = 0xFFFFFFFF;
1344         }
1345
1346         duprintf("translate_compat_table: size %u\n", info->size);
1347         j = 0;
1348         xt_compat_lock(NFPROTO_ARP);
1349         xt_compat_init_offsets(NFPROTO_ARP, number);
1350         /* Walk through entries, checking offsets. */
1351         xt_entry_foreach(iter0, entry0, total_size) {
1352                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1353                                                         entry0,
1354                                                         entry0 + total_size,
1355                                                         hook_entries,
1356                                                         underflows,
1357                                                         name);
1358                 if (ret != 0)
1359                         goto out_unlock;
1360                 ++j;
1361         }
1362
1363         ret = -EINVAL;
1364         if (j != number) {
1365                 duprintf("translate_compat_table: %u not %u entries\n",
1366                          j, number);
1367                 goto out_unlock;
1368         }
1369
1370         /* Check hooks all assigned */
1371         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1372                 /* Only hooks which are valid */
1373                 if (!(valid_hooks & (1 << i)))
1374                         continue;
1375                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1376                         duprintf("Invalid hook entry %u %u\n",
1377                                  i, hook_entries[i]);
1378                         goto out_unlock;
1379                 }
1380                 if (info->underflow[i] == 0xFFFFFFFF) {
1381                         duprintf("Invalid underflow %u %u\n",
1382                                  i, underflows[i]);
1383                         goto out_unlock;
1384                 }
1385         }
1386
1387         ret = -ENOMEM;
1388         newinfo = xt_alloc_table_info(size);
1389         if (!newinfo)
1390                 goto out_unlock;
1391
1392         newinfo->number = number;
1393         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1394                 newinfo->hook_entry[i] = info->hook_entry[i];
1395                 newinfo->underflow[i] = info->underflow[i];
1396         }
1397         entry1 = newinfo->entries[raw_smp_processor_id()];
1398         pos = entry1;
1399         size = total_size;
1400         xt_entry_foreach(iter0, entry0, total_size) {
1401                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1402                                                   name, newinfo, entry1);
1403                 if (ret != 0)
1404                         break;
1405         }
1406         xt_compat_flush_offsets(NFPROTO_ARP);
1407         xt_compat_unlock(NFPROTO_ARP);
1408         if (ret)
1409                 goto free_newinfo;
1410
1411         ret = -ELOOP;
1412         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1413                 goto free_newinfo;
1414
1415         i = 0;
1416         xt_entry_foreach(iter1, entry1, newinfo->size) {
1417                 ret = check_target(iter1, name);
1418                 if (ret != 0)
1419                         break;
1420                 ++i;
1421                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1422                     XT_ERROR_TARGET) == 0)
1423                         ++newinfo->stacksize;
1424         }
1425         if (ret) {
1426                 /*
1427                  * The first i matches need cleanup_entry (calls ->destroy)
1428                  * because they had called ->check already. The other j-i
1429                  * entries need only release.
1430                  */
1431                 int skip = i;
1432                 j -= i;
1433                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1434                         if (skip-- > 0)
1435                                 continue;
1436                         if (j-- == 0)
1437                                 break;
1438                         compat_release_entry(iter0);
1439                 }
1440                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1441                         if (i-- == 0)
1442                                 break;
1443                         cleanup_entry(iter1);
1444                 }
1445                 xt_free_table_info(newinfo);
1446                 return ret;
1447         }
1448
1449         /* And one copy for every other CPU */
1450         for_each_possible_cpu(i)
1451                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1452                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1453
1454         *pinfo = newinfo;
1455         *pentry0 = entry1;
1456         xt_free_table_info(info);
1457         return 0;
1458
1459 free_newinfo:
1460         xt_free_table_info(newinfo);
1461 out:
1462         xt_entry_foreach(iter0, entry0, total_size) {
1463                 if (j-- == 0)
1464                         break;
1465                 compat_release_entry(iter0);
1466         }
1467         return ret;
1468 out_unlock:
1469         xt_compat_flush_offsets(NFPROTO_ARP);
1470         xt_compat_unlock(NFPROTO_ARP);
1471         goto out;
1472 }
1473
1474 struct compat_arpt_replace {
1475         char                            name[XT_TABLE_MAXNAMELEN];
1476         u32                             valid_hooks;
1477         u32                             num_entries;
1478         u32                             size;
1479         u32                             hook_entry[NF_ARP_NUMHOOKS];
1480         u32                             underflow[NF_ARP_NUMHOOKS];
1481         u32                             num_counters;
1482         compat_uptr_t                   counters;
1483         struct compat_arpt_entry        entries[0];
1484 };
1485
1486 static int compat_do_replace(struct net *net, void __user *user,
1487                              unsigned int len)
1488 {
1489         int ret;
1490         struct compat_arpt_replace tmp;
1491         struct xt_table_info *newinfo;
1492         void *loc_cpu_entry;
1493         struct arpt_entry *iter;
1494
1495         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1496                 return -EFAULT;
1497
1498         /* overflow check */
1499         if (tmp.size >= INT_MAX / num_possible_cpus())
1500                 return -ENOMEM;
1501         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1502                 return -ENOMEM;
1503         tmp.name[sizeof(tmp.name)-1] = 0;
1504
1505         newinfo = xt_alloc_table_info(tmp.size);
1506         if (!newinfo)
1507                 return -ENOMEM;
1508
1509         /* choose the copy that is on our node/cpu */
1510         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1511         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1512                 ret = -EFAULT;
1513                 goto free_newinfo;
1514         }
1515
1516         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1517                                      &newinfo, &loc_cpu_entry, tmp.size,
1518                                      tmp.num_entries, tmp.hook_entry,
1519                                      tmp.underflow);
1520         if (ret != 0)
1521                 goto free_newinfo;
1522
1523         duprintf("compat_do_replace: Translated table\n");
1524
1525         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1526                            tmp.num_counters, compat_ptr(tmp.counters));
1527         if (ret)
1528                 goto free_newinfo_untrans;
1529         return 0;
1530
1531  free_newinfo_untrans:
1532         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1533                 cleanup_entry(iter);
1534  free_newinfo:
1535         xt_free_table_info(newinfo);
1536         return ret;
1537 }
1538
1539 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1540                                   unsigned int len)
1541 {
1542         int ret;
1543
1544         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1545                 return -EPERM;
1546
1547         switch (cmd) {
1548         case ARPT_SO_SET_REPLACE:
1549                 ret = compat_do_replace(sock_net(sk), user, len);
1550                 break;
1551
1552         case ARPT_SO_SET_ADD_COUNTERS:
1553                 ret = do_add_counters(sock_net(sk), user, len, 1);
1554                 break;
1555
1556         default:
1557                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1558                 ret = -EINVAL;
1559         }
1560
1561         return ret;
1562 }
1563
1564 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1565                                      compat_uint_t *size,
1566                                      struct xt_counters *counters,
1567                                      unsigned int i)
1568 {
1569         struct xt_entry_target *t;
1570         struct compat_arpt_entry __user *ce;
1571         u_int16_t target_offset, next_offset;
1572         compat_uint_t origsize;
1573         int ret;
1574
1575         origsize = *size;
1576         ce = (struct compat_arpt_entry __user *)*dstptr;
1577         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1578             copy_to_user(&ce->counters, &counters[i],
1579             sizeof(counters[i])) != 0)
1580                 return -EFAULT;
1581
1582         *dstptr += sizeof(struct compat_arpt_entry);
1583         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1584
1585         target_offset = e->target_offset - (origsize - *size);
1586
1587         t = arpt_get_target(e);
1588         ret = xt_compat_target_to_user(t, dstptr, size);
1589         if (ret)
1590                 return ret;
1591         next_offset = e->next_offset - (origsize - *size);
1592         if (put_user(target_offset, &ce->target_offset) != 0 ||
1593             put_user(next_offset, &ce->next_offset) != 0)
1594                 return -EFAULT;
1595         return 0;
1596 }
1597
1598 static int compat_copy_entries_to_user(unsigned int total_size,
1599                                        struct xt_table *table,
1600                                        void __user *userptr)
1601 {
1602         struct xt_counters *counters;
1603         const struct xt_table_info *private = table->private;
1604         void __user *pos;
1605         unsigned int size;
1606         int ret = 0;
1607         void *loc_cpu_entry;
1608         unsigned int i = 0;
1609         struct arpt_entry *iter;
1610
1611         counters = alloc_counters(table);
1612         if (IS_ERR(counters))
1613                 return PTR_ERR(counters);
1614
1615         /* choose the copy on our node/cpu */
1616         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1617         pos = userptr;
1618         size = total_size;
1619         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1620                 ret = compat_copy_entry_to_user(iter, &pos,
1621                                                 &size, counters, i++);
1622                 if (ret != 0)
1623                         break;
1624         }
1625         vfree(counters);
1626         return ret;
1627 }
1628
1629 struct compat_arpt_get_entries {
1630         char name[XT_TABLE_MAXNAMELEN];
1631         compat_uint_t size;
1632         struct compat_arpt_entry entrytable[0];
1633 };
1634
1635 static int compat_get_entries(struct net *net,
1636                               struct compat_arpt_get_entries __user *uptr,
1637                               int *len)
1638 {
1639         int ret;
1640         struct compat_arpt_get_entries get;
1641         struct xt_table *t;
1642
1643         if (*len < sizeof(get)) {
1644                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1645                 return -EINVAL;
1646         }
1647         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1648                 return -EFAULT;
1649         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1650                 duprintf("compat_get_entries: %u != %zu\n",
1651                          *len, sizeof(get) + get.size);
1652                 return -EINVAL;
1653         }
1654
1655         xt_compat_lock(NFPROTO_ARP);
1656         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1657         if (!IS_ERR_OR_NULL(t)) {
1658                 const struct xt_table_info *private = t->private;
1659                 struct xt_table_info info;
1660
1661                 duprintf("t->private->number = %u\n", private->number);
1662                 ret = compat_table_info(private, &info);
1663                 if (!ret && get.size == info.size) {
1664                         ret = compat_copy_entries_to_user(private->size,
1665                                                           t, uptr->entrytable);
1666                 } else if (!ret) {
1667                         duprintf("compat_get_entries: I've got %u not %u!\n",
1668                                  private->size, get.size);
1669                         ret = -EAGAIN;
1670                 }
1671                 xt_compat_flush_offsets(NFPROTO_ARP);
1672                 module_put(t->me);
1673                 xt_table_unlock(t);
1674         } else
1675                 ret = t ? PTR_ERR(t) : -ENOENT;
1676
1677         xt_compat_unlock(NFPROTO_ARP);
1678         return ret;
1679 }
1680
1681 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1682
1683 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1684                                   int *len)
1685 {
1686         int ret;
1687
1688         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1689                 return -EPERM;
1690
1691         switch (cmd) {
1692         case ARPT_SO_GET_INFO:
1693                 ret = get_info(sock_net(sk), user, len, 1);
1694                 break;
1695         case ARPT_SO_GET_ENTRIES:
1696                 ret = compat_get_entries(sock_net(sk), user, len);
1697                 break;
1698         default:
1699                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1700         }
1701         return ret;
1702 }
1703 #endif
1704
1705 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1706 {
1707         int ret;
1708
1709         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1710                 return -EPERM;
1711
1712         switch (cmd) {
1713         case ARPT_SO_SET_REPLACE:
1714                 ret = do_replace(sock_net(sk), user, len);
1715                 break;
1716
1717         case ARPT_SO_SET_ADD_COUNTERS:
1718                 ret = do_add_counters(sock_net(sk), user, len, 0);
1719                 break;
1720
1721         default:
1722                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1723                 ret = -EINVAL;
1724         }
1725
1726         return ret;
1727 }
1728
1729 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1730 {
1731         int ret;
1732
1733         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1734                 return -EPERM;
1735
1736         switch (cmd) {
1737         case ARPT_SO_GET_INFO:
1738                 ret = get_info(sock_net(sk), user, len, 0);
1739                 break;
1740
1741         case ARPT_SO_GET_ENTRIES:
1742                 ret = get_entries(sock_net(sk), user, len);
1743                 break;
1744
1745         case ARPT_SO_GET_REVISION_TARGET: {
1746                 struct xt_get_revision rev;
1747
1748                 if (*len != sizeof(rev)) {
1749                         ret = -EINVAL;
1750                         break;
1751                 }
1752                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1753                         ret = -EFAULT;
1754                         break;
1755                 }
1756                 rev.name[sizeof(rev.name)-1] = 0;
1757
1758                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1759                                                          rev.revision, 1, &ret),
1760                                         "arpt_%s", rev.name);
1761                 break;
1762         }
1763
1764         default:
1765                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1766                 ret = -EINVAL;
1767         }
1768
1769         return ret;
1770 }
1771
1772 struct xt_table *arpt_register_table(struct net *net,
1773                                      const struct xt_table *table,
1774                                      const struct arpt_replace *repl)
1775 {
1776         int ret;
1777         struct xt_table_info *newinfo;
1778         struct xt_table_info bootstrap = {0};
1779         void *loc_cpu_entry;
1780         struct xt_table *new_table;
1781
1782         newinfo = xt_alloc_table_info(repl->size);
1783         if (!newinfo) {
1784                 ret = -ENOMEM;
1785                 goto out;
1786         }
1787
1788         /* choose the copy on our node/cpu */
1789         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1790         memcpy(loc_cpu_entry, repl->entries, repl->size);
1791
1792         ret = translate_table(newinfo, loc_cpu_entry, repl);
1793         duprintf("arpt_register_table: translate table gives %d\n", ret);
1794         if (ret != 0)
1795                 goto out_free;
1796
1797         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1798         if (IS_ERR(new_table)) {
1799                 ret = PTR_ERR(new_table);
1800                 goto out_free;
1801         }
1802         return new_table;
1803
1804 out_free:
1805         xt_free_table_info(newinfo);
1806 out:
1807         return ERR_PTR(ret);
1808 }
1809
1810 void arpt_unregister_table(struct xt_table *table)
1811 {
1812         struct xt_table_info *private;
1813         void *loc_cpu_entry;
1814         struct module *table_owner = table->me;
1815         struct arpt_entry *iter;
1816
1817         private = xt_unregister_table(table);
1818
1819         /* Decrease module usage counts and free resources */
1820         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1821         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1822                 cleanup_entry(iter);
1823         if (private->number > private->initial_entries)
1824                 module_put(table_owner);
1825         xt_free_table_info(private);
1826 }
1827
1828 /* The built-in targets: standard (NULL) and error. */
1829 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1830         {
1831                 .name             = XT_STANDARD_TARGET,
1832                 .targetsize       = sizeof(int),
1833                 .family           = NFPROTO_ARP,
1834 #ifdef CONFIG_COMPAT
1835                 .compatsize       = sizeof(compat_int_t),
1836                 .compat_from_user = compat_standard_from_user,
1837                 .compat_to_user   = compat_standard_to_user,
1838 #endif
1839         },
1840         {
1841                 .name             = XT_ERROR_TARGET,
1842                 .target           = arpt_error,
1843                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1844                 .family           = NFPROTO_ARP,
1845         },
1846 };
1847
1848 static struct nf_sockopt_ops arpt_sockopts = {
1849         .pf             = PF_INET,
1850         .set_optmin     = ARPT_BASE_CTL,
1851         .set_optmax     = ARPT_SO_SET_MAX+1,
1852         .set            = do_arpt_set_ctl,
1853 #ifdef CONFIG_COMPAT
1854         .compat_set     = compat_do_arpt_set_ctl,
1855 #endif
1856         .get_optmin     = ARPT_BASE_CTL,
1857         .get_optmax     = ARPT_SO_GET_MAX+1,
1858         .get            = do_arpt_get_ctl,
1859 #ifdef CONFIG_COMPAT
1860         .compat_get     = compat_do_arpt_get_ctl,
1861 #endif
1862         .owner          = THIS_MODULE,
1863 };
1864
1865 static int __net_init arp_tables_net_init(struct net *net)
1866 {
1867         return xt_proto_init(net, NFPROTO_ARP);
1868 }
1869
1870 static void __net_exit arp_tables_net_exit(struct net *net)
1871 {
1872         xt_proto_fini(net, NFPROTO_ARP);
1873 }
1874
1875 static struct pernet_operations arp_tables_net_ops = {
1876         .init = arp_tables_net_init,
1877         .exit = arp_tables_net_exit,
1878 };
1879
1880 static int __init arp_tables_init(void)
1881 {
1882         int ret;
1883
1884         ret = register_pernet_subsys(&arp_tables_net_ops);
1885         if (ret < 0)
1886                 goto err1;
1887
1888         /* No one else will be downing sem now, so we won't sleep */
1889         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1890         if (ret < 0)
1891                 goto err2;
1892
1893         /* Register setsockopt */
1894         ret = nf_register_sockopt(&arpt_sockopts);
1895         if (ret < 0)
1896                 goto err4;
1897
1898         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1899         return 0;
1900
1901 err4:
1902         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1903 err2:
1904         unregister_pernet_subsys(&arp_tables_net_ops);
1905 err1:
1906         return ret;
1907 }
1908
1909 static void __exit arp_tables_fini(void)
1910 {
1911         nf_unregister_sockopt(&arpt_sockopts);
1912         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1913         unregister_pernet_subsys(&arp_tables_net_ops);
1914 }
1915
1916 EXPORT_SYMBOL(arpt_register_table);
1917 EXPORT_SYMBOL(arpt_unregister_table);
1918 EXPORT_SYMBOL(arpt_do_table);
1919
1920 module_init(arp_tables_init);
1921 module_exit(arp_tables_fini);