net/ipv4/netfilter/arp_tables.c

   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  *
  10  */
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/capability.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/kmod.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/mutex.h>
  23 #include <linux/err.h>
  24 #include <net/compat.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter_arp/arp_tables.h>
  30 #include "../../netfilter/xt_repldata.h"
  31
  32 MODULE_LICENSE("GPL");
  33 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  34 MODULE_DESCRIPTION("arptables core");
  35
  36 /*#define DEBUG_ARP_TABLES*/
  37 /*#define DEBUG_ARP_TABLES_USER*/
  38
  39 #ifdef DEBUG_ARP_TABLES
  40 #define dprintf(format, args...)  printk(format , ## args)
  41 #else
  42 #define dprintf(format, args...)
  43 #endif
  44
  45 #ifdef DEBUG_ARP_TABLES_USER
  46 #define duprintf(format, args...) printk(format , ## args)
  47 #else
  48 #define duprintf(format, args...)
  49 #endif
  50
  51 #ifdef CONFIG_NETFILTER_DEBUG
  52 #define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  53 #else
  54 #define ARP_NF_ASSERT(x)
  55 #endif
  56
  57 void *arpt_alloc_initial_table(const struct xt_table *info)
  58 {
  59         return xt_alloc_initial_table(arpt, ARPT);
  60 }
  61 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  62
  63 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  64                                       const char *hdr_addr, int len)
  65 {
  66         int i, ret;
  67
  68         if (len > ARPT_DEV_ADDR_LEN_MAX)
  69                 len = ARPT_DEV_ADDR_LEN_MAX;
  70
  71         ret = 0;
  72         for (i = 0; i < len; i++)
  73                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  74
  75         return ret != 0;
  76 }
  77
  78 /*
  79  * Unfortunately, _b and _mask are not aligned to an int (or long int)
  80  * Some arches dont care, unrolling the loop is a win on them.
  81  * For other arches, we only have a 16bit alignement.
  82  */
  83 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  84 {
  85 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  86         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  87 #else
  88         unsigned long ret = 0;
  89         const u16 *a = (const u16 *)_a;
  90         const u16 *b = (const u16 *)_b;
  91         const u16 *mask = (const u16 *)_mask;
  92         int i;
  93
  94         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  95                 ret |= (a[i] ^ b[i]) & mask[i];
  96 #endif
  97         return ret;
  98 }
  99
 100 /* Returns whether packet matches rule or not. */
 101 static inline int arp_packet_match(const struct arphdr *arphdr,
 102                                    struct net_device *dev,
 103                                    const char *indev,
 104                                    const char *outdev,
 105                                    const struct arpt_arp *arpinfo)
 106 {
 107         const char *arpptr = (char *)(arphdr + 1);
 108         const char *src_devaddr, *tgt_devaddr;
 109         __be32 src_ipaddr, tgt_ipaddr;
 110         long ret;
 111
 112 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 113
 114         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 115                   ARPT_INV_ARPOP)) {
 116                 dprintf("ARP operation field mismatch.\n");
 117                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 118                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 119                 return 0;
 120         }
 121
 122         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 123                   ARPT_INV_ARPHRD)) {
 124                 dprintf("ARP hardware address format mismatch.\n");
 125                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 126                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 127                 return 0;
 128         }
 129
 130         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 131                   ARPT_INV_ARPPRO)) {
 132                 dprintf("ARP protocol address format mismatch.\n");
 133                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 134                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 135                 return 0;
 136         }
 137
 138         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 139                   ARPT_INV_ARPHLN)) {
 140                 dprintf("ARP hardware address length mismatch.\n");
 141                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 142                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 143                 return 0;
 144         }
 145
 146         src_devaddr = arpptr;
 147         arpptr += dev->addr_len;
 148         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 149         arpptr += sizeof(u32);
 150         tgt_devaddr = arpptr;
 151         arpptr += dev->addr_len;
 152         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 153
 154         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 155                   ARPT_INV_SRCDEVADDR) ||
 156             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 157                   ARPT_INV_TGTDEVADDR)) {
 158                 dprintf("Source or target device address mismatch.\n");
 159
 160                 return 0;
 161         }
 162
 163         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 164                   ARPT_INV_SRCIP) ||
 165             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 166                   ARPT_INV_TGTIP)) {
 167                 dprintf("Source or target IP address mismatch.\n");
 168
 169                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 170                         &src_ipaddr,
 171                         &arpinfo->smsk.s_addr,
 172                         &arpinfo->src.s_addr,
 173                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 174                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 175                         &tgt_ipaddr,
 176                         &arpinfo->tmsk.s_addr,
 177                         &arpinfo->tgt.s_addr,
 178                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 179                 return 0;
 180         }
 181
 182         /* Look for ifname matches.  */
 183         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 184
 185         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 186                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 187                         indev, arpinfo->iniface,
 188                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 189                 return 0;
 190         }
 191
 192         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 193
 194         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 195                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 196                         outdev, arpinfo->outiface,
 197                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 198                 return 0;
 199         }
 200
 201         return 1;
 202 #undef FWINV
 203 }
 204
 205 static inline int arp_checkentry(const struct arpt_arp *arp)
 206 {
 207         if (arp->flags & ~ARPT_F_MASK) {
 208                 duprintf("Unknown flag bits set: %08X\n",
 209                          arp->flags & ~ARPT_F_MASK);
 210                 return 0;
 211         }
 212         if (arp->invflags & ~ARPT_INV_MASK) {
 213                 duprintf("Unknown invflag bits set: %08X\n",
 214                          arp->invflags & ~ARPT_INV_MASK);
 215                 return 0;
 216         }
 217
 218         return 1;
 219 }
 220
 221 static unsigned int
 222 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 223 {
 224         net_err_ratelimited("arp_tables: error: '%s'\n",
 225                             (const char *)par->targinfo);
 226
 227         return NF_DROP;
 228 }
 229
 230 static inline const struct xt_entry_target *
 231 arpt_get_target_c(const struct arpt_entry *e)
 232 {
 233         return arpt_get_target((struct arpt_entry *)e);
 234 }
 235
 236 static inline struct arpt_entry *
 237 get_entry(const void *base, unsigned int offset)
 238 {
 239         return (struct arpt_entry *)(base + offset);
 240 }
 241
 242 static inline __pure
 243 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 244 {
 245         return (void *)entry + entry->next_offset;
 246 }
 247
 248 unsigned int arpt_do_table(struct sk_buff *skb,
 249                            unsigned int hook,
 250                            const struct net_device *in,
 251                            const struct net_device *out,
 252                            struct xt_table *table)
 253 {
 254         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 255         unsigned int verdict = NF_DROP;
 256         const struct arphdr *arp;
 257         struct arpt_entry *e, *back;
 258         const char *indev, *outdev;
 259         void *table_base;
 260         const struct xt_table_info *private;
 261         struct xt_action_param acpar;
 262         unsigned int addend;
 263
 264         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 265                 return NF_DROP;
 266
 267         indev = in ? in->name : nulldevname;
 268         outdev = out ? out->name : nulldevname;
 269
 270         local_bh_disable();
 271         addend = xt_write_recseq_begin();
 272         private = table->private;
 273         table_base = private->entries[smp_processor_id()];
 274
 275         e = get_entry(table_base, private->hook_entry[hook]);
 276         back = get_entry(table_base, private->underflow[hook]);
 277
 278         acpar.in      = in;
 279         acpar.out     = out;
 280         acpar.hooknum = hook;
 281         acpar.family  = NFPROTO_ARP;
 282         acpar.hotdrop = false;
 283
 284         arp = arp_hdr(skb);
 285         do {
 286                 const struct xt_entry_target *t;
 287
 288                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 289                         e = arpt_next_entry(e);
 290                         continue;
 291                 }
 292
 293                 ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
 294
 295                 t = arpt_get_target_c(e);
 296
 297                 /* Standard target? */
 298                 if (!t->u.kernel.target->target) {
 299                         int v;
 300
 301                         v = ((struct xt_standard_target *)t)->verdict;
 302                         if (v < 0) {
 303                                 /* Pop from stack? */
 304                                 if (v != XT_RETURN) {
 305                                         verdict = (unsigned int)(-v) - 1;
 306                                         break;
 307                                 }
 308                                 e = back;
 309                                 back = get_entry(table_base, back->comefrom);
 310                                 continue;
 311                         }
 312                         if (table_base + v
 313                             != arpt_next_entry(e)) {
 314                                 /* Save old back ptr in next entry */
 315                                 struct arpt_entry *next = arpt_next_entry(e);
 316                                 next->comefrom = (void *)back - table_base;
 317
 318                                 /* set back pointer to next entry */
 319                                 back = next;
 320                         }
 321
 322                         e = get_entry(table_base, v);
 323                         continue;
 324                 }
 325
 326                 /* Targets which reenter must return
 327                  * abs. verdicts
 328                  */
 329                 acpar.target   = t->u.kernel.target;
 330                 acpar.targinfo = t->data;
 331                 verdict = t->u.kernel.target->target(skb, &acpar);
 332
 333                 /* Target might have changed stuff. */
 334                 arp = arp_hdr(skb);
 335
 336                 if (verdict == XT_CONTINUE)
 337                         e = arpt_next_entry(e);
 338                 else
 339                         /* Verdict */
 340                         break;
 341         } while (!acpar.hotdrop);
 342         xt_write_recseq_end(addend);
 343         local_bh_enable();
 344
 345         if (acpar.hotdrop)
 346                 return NF_DROP;
 347         else
 348                 return verdict;
 349 }
 350
 351 /* All zeroes == unconditional rule. */
 352 static inline bool unconditional(const struct arpt_arp *arp)
 353 {
 354         static const struct arpt_arp uncond;
 355
 356         return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 357 }
 358
 359 /* Figures out from what hook each rule can be called: returns 0 if
 360  * there are loops.  Puts hook bitmask in comefrom.
 361  */
 362 static int mark_source_chains(const struct xt_table_info *newinfo,
 363                               unsigned int valid_hooks, void *entry0)
 364 {
 365         unsigned int hook;
 366
 367         /* No recursion; use packet counter to save back ptrs (reset
 368          * to 0 as we leave), and comefrom to save source hook bitmask.
 369          */
 370         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 371                 unsigned int pos = newinfo->hook_entry[hook];
 372                 struct arpt_entry *e
 373                         = (struct arpt_entry *)(entry0 + pos);
 374
 375                 if (!(valid_hooks & (1 << hook)))
 376                         continue;
 377
 378                 /* Set initial back pointer. */
 379                 e->counters.pcnt = pos;
 380
 381                 for (;;) {
 382                         const struct xt_standard_target *t
 383                                 = (void *)arpt_get_target_c(e);
 384                         int visited = e->comefrom & (1 << hook);
 385
 386                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 387                                 pr_notice("arptables: loop hook %u pos %u %08X.\n",
 388                                        hook, pos, e->comefrom);
 389                                 return 0;
 390                         }
 391                         e->comefrom
 392                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 393
 394                         /* Unconditional return/END. */
 395                         if ((e->target_offset == sizeof(struct arpt_entry) &&
 396                              (strcmp(t->target.u.user.name,
 397                                      XT_STANDARD_TARGET) == 0) &&
 398                              t->verdict < 0 && unconditional(&e->arp)) ||
 399                             visited) {
 400                                 unsigned int oldpos, size;
 401
 402                                 if ((strcmp(t->target.u.user.name,
 403                                             XT_STANDARD_TARGET) == 0) &&
 404                                     t->verdict < -NF_MAX_VERDICT - 1) {
 405                                         duprintf("mark_source_chains: bad "
 406                                                 "negative verdict (%i)\n",
 407                                                                 t->verdict);
 408                                         return 0;
 409                                 }
 410
 411                                 /* Return: backtrack through the last
 412                                  * big jump.
 413                                  */
 414                                 do {
 415                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 416                                         oldpos = pos;
 417                                         pos = e->counters.pcnt;
 418                                         e->counters.pcnt = 0;
 419
 420                                         /* We're at the start. */
 421                                         if (pos == oldpos)
 422                                                 goto next;
 423
 424                                         e = (struct arpt_entry *)
 425                                                 (entry0 + pos);
 426                                 } while (oldpos == pos + e->next_offset);
 427
 428                                 /* Move along one */
 429                                 size = e->next_offset;
 430                                 e = (struct arpt_entry *)
 431                                         (entry0 + pos + size);
 432                                 e->counters.pcnt = pos;
 433                                 pos += size;
 434                         } else {
 435                                 int newpos = t->verdict;
 436
 437                                 if (strcmp(t->target.u.user.name,
 438                                            XT_STANDARD_TARGET) == 0 &&
 439                                     newpos >= 0) {
 440                                         if (newpos > newinfo->size -
 441                                                 sizeof(struct arpt_entry)) {
 442                                                 duprintf("mark_source_chains: "
 443                                                         "bad verdict (%i)\n",
 444                                                                 newpos);
 445                                                 return 0;
 446                                         }
 447
 448                                         /* This a jump; chase it. */
 449                                         duprintf("Jump rule %u -> %u\n",
 450                                                  pos, newpos);
 451                                 } else {
 452                                         /* ... this is a fallthru */
 453                                         newpos = pos + e->next_offset;
 454                                 }
 455                                 e = (struct arpt_entry *)
 456                                         (entry0 + newpos);
 457                                 e->counters.pcnt = pos;
 458                                 pos = newpos;
 459                         }
 460                 }
 461                 next:
 462                 duprintf("Finished chain %u\n", hook);
 463         }
 464         return 1;
 465 }
 466
 467 static inline int check_entry(const struct arpt_entry *e, const char *name)
 468 {
 469         const struct xt_entry_target *t;
 470
 471         if (!arp_checkentry(&e->arp)) {
 472                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 473                 return -EINVAL;
 474         }
 475
 476         if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
 477                 return -EINVAL;
 478
 479         t = arpt_get_target_c(e);
 480         if (e->target_offset + t->u.target_size > e->next_offset)
 481                 return -EINVAL;
 482
 483         return 0;
 484 }
 485
 486 static inline int check_target(struct arpt_entry *e, const char *name)
 487 {
 488         struct xt_entry_target *t = arpt_get_target(e);
 489         int ret;
 490         struct xt_tgchk_param par = {
 491                 .table     = name,
 492                 .entryinfo = e,
 493                 .target    = t->u.kernel.target,
 494                 .targinfo  = t->data,
 495                 .hook_mask = e->comefrom,
 496                 .family    = NFPROTO_ARP,
 497         };
 498
 499         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 500         if (ret < 0) {
 501                 duprintf("arp_tables: check failed for `%s'.\n",
 502                          t->u.kernel.target->name);
 503                 return ret;
 504         }
 505         return 0;
 506 }
 507
 508 static inline int
 509 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 510 {
 511         struct xt_entry_target *t;
 512         struct xt_target *target;
 513         int ret;
 514
 515         ret = check_entry(e, name);
 516         if (ret)
 517                 return ret;
 518
 519         t = arpt_get_target(e);
 520         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 521                                         t->u.user.revision);
 522         if (IS_ERR(target)) {
 523                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 524                 ret = PTR_ERR(target);
 525                 goto out;
 526         }
 527         t->u.kernel.target = target;
 528
 529         ret = check_target(e, name);
 530         if (ret)
 531                 goto err;
 532         return 0;
 533 err:
 534         module_put(t->u.kernel.target->me);
 535 out:
 536         return ret;
 537 }
 538
 539 static bool check_underflow(const struct arpt_entry *e)
 540 {
 541         const struct xt_entry_target *t;
 542         unsigned int verdict;
 543
 544         if (!unconditional(&e->arp))
 545                 return false;
 546         t = arpt_get_target_c(e);
 547         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 548                 return false;
 549         verdict = ((struct xt_standard_target *)t)->verdict;
 550         verdict = -verdict - 1;
 551         return verdict == NF_DROP || verdict == NF_ACCEPT;
 552 }
 553
 554 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 555                                              struct xt_table_info *newinfo,
 556                                              const unsigned char *base,
 557                                              const unsigned char *limit,
 558                                              const unsigned int *hook_entries,
 559                                              const unsigned int *underflows,
 560                                              unsigned int valid_hooks)
 561 {
 562         unsigned int h;
 563
 564         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 565             (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 566                 duprintf("Bad offset %p\n", e);
 567                 return -EINVAL;
 568         }
 569
 570         if (e->next_offset
 571             < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 572                 duprintf("checking: element %p size %u\n",
 573                          e, e->next_offset);
 574                 return -EINVAL;
 575         }
 576
 577         /* Check hooks & underflows */
 578         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 579                 if (!(valid_hooks & (1 << h)))
 580                         continue;
 581                 if ((unsigned char *)e - base == hook_entries[h])
 582                         newinfo->hook_entry[h] = hook_entries[h];
 583                 if ((unsigned char *)e - base == underflows[h]) {
 584                         if (!check_underflow(e)) {
 585                                 pr_err("Underflows must be unconditional and "
 586                                        "use the STANDARD target with "
 587                                        "ACCEPT/DROP\n");
 588                                 return -EINVAL;
 589                         }
 590                         newinfo->underflow[h] = underflows[h];
 591                 }
 592         }
 593
 594         /* Clear counters and comefrom */
 595         e->counters = ((struct xt_counters) { 0, 0 });
 596         e->comefrom = 0;
 597         return 0;
 598 }
 599
 600 static inline void cleanup_entry(struct arpt_entry *e)
 601 {
 602         struct xt_tgdtor_param par;
 603         struct xt_entry_target *t;
 604
 605         t = arpt_get_target(e);
 606         par.target   = t->u.kernel.target;
 607         par.targinfo = t->data;
 608         par.family   = NFPROTO_ARP;
 609         if (par.target->destroy != NULL)
 610                 par.target->destroy(&par);
 611         module_put(par.target->me);
 612 }
 613
 614 /* Checks and translates the user-supplied table segment (held in
 615  * newinfo).
 616  */
 617 static int translate_table(struct xt_table_info *newinfo, void *entry0,
 618                            const struct arpt_replace *repl)
 619 {
 620         struct arpt_entry *iter;
 621         unsigned int i;
 622         int ret = 0;
 623
 624         newinfo->size = repl->size;
 625         newinfo->number = repl->num_entries;
 626
 627         /* Init all hooks to impossible value. */
 628         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 629                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 630                 newinfo->underflow[i] = 0xFFFFFFFF;
 631         }
 632
 633         duprintf("translate_table: size %u\n", newinfo->size);
 634         i = 0;
 635
 636         /* Walk through entries, checking offsets. */
 637         xt_entry_foreach(iter, entry0, newinfo->size) {
 638                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 639                                                  entry0 + repl->size,
 640                                                  repl->hook_entry,
 641                                                  repl->underflow,
 642                                                  repl->valid_hooks);
 643                 if (ret != 0)
 644                         break;
 645                 ++i;
 646                 if (strcmp(arpt_get_target(iter)->u.user.name,
 647                     XT_ERROR_TARGET) == 0)
 648                         ++newinfo->stacksize;
 649         }
 650         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 651         if (ret != 0)
 652                 return ret;
 653
 654         if (i != repl->num_entries) {
 655                 duprintf("translate_table: %u not %u entries\n",
 656                          i, repl->num_entries);
 657                 return -EINVAL;
 658         }
 659
 660         /* Check hooks all assigned */
 661         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 662                 /* Only hooks which are valid */
 663                 if (!(repl->valid_hooks & (1 << i)))
 664                         continue;
 665                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 666                         duprintf("Invalid hook entry %u %u\n",
 667                                  i, repl->hook_entry[i]);
 668                         return -EINVAL;
 669                 }
 670                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 671                         duprintf("Invalid underflow %u %u\n",
 672                                  i, repl->underflow[i]);
 673                         return -EINVAL;
 674                 }
 675         }
 676
 677         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 678                 duprintf("Looping hook\n");
 679                 return -ELOOP;
 680         }
 681
 682         /* Finally, each sanity check must pass */
 683         i = 0;
 684         xt_entry_foreach(iter, entry0, newinfo->size) {
 685                 ret = find_check_entry(iter, repl->name, repl->size);
 686                 if (ret != 0)
 687                         break;
 688                 ++i;
 689         }
 690
 691         if (ret != 0) {
 692                 xt_entry_foreach(iter, entry0, newinfo->size) {
 693                         if (i-- == 0)
 694                                 break;
 695                         cleanup_entry(iter);
 696                 }
 697                 return ret;
 698         }
 699
 700         /* And one copy for every other CPU */
 701         for_each_possible_cpu(i) {
 702                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 703                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 704         }
 705
 706         return ret;
 707 }
 708
 709 static void get_counters(const struct xt_table_info *t,
 710                          struct xt_counters counters[])
 711 {
 712         struct arpt_entry *iter;
 713         unsigned int cpu;
 714         unsigned int i;
 715
 716         for_each_possible_cpu(cpu) {
 717                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 718
 719                 i = 0;
 720                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
 721                         u64 bcnt, pcnt;
 722                         unsigned int start;
 723
 724                         do {
 725                                 start = read_seqcount_begin(s);
 726                                 bcnt = iter->counters.bcnt;
 727                                 pcnt = iter->counters.pcnt;
 728                         } while (read_seqcount_retry(s, start));
 729
 730                         ADD_COUNTER(counters[i], bcnt, pcnt);
 731                         ++i;
 732                 }
 733         }
 734 }
 735
 736 static struct xt_counters *alloc_counters(const struct xt_table *table)
 737 {
 738         unsigned int countersize;
 739         struct xt_counters *counters;
 740         const struct xt_table_info *private = table->private;
 741
 742         /* We need atomic snapshot of counters: rest doesn't change
 743          * (other than comefrom, which userspace doesn't care
 744          * about).
 745          */
 746         countersize = sizeof(struct xt_counters) * private->number;
 747         counters = vzalloc(countersize);
 748
 749         if (counters == NULL)
 750                 return ERR_PTR(-ENOMEM);
 751
 752         get_counters(private, counters);
 753
 754         return counters;
 755 }
 756
 757 static int copy_entries_to_user(unsigned int total_size,
 758                                 const struct xt_table *table,
 759                                 void __user *userptr)
 760 {
 761         unsigned int off, num;
 762         const struct arpt_entry *e;
 763         struct xt_counters *counters;
 764         struct xt_table_info *private = table->private;
 765         int ret = 0;
 766         void *loc_cpu_entry;
 767
 768         counters = alloc_counters(table);
 769         if (IS_ERR(counters))
 770                 return PTR_ERR(counters);
 771
 772         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 773         /* ... then copy entire thing ... */
 774         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 775                 ret = -EFAULT;
 776                 goto free_counters;
 777         }
 778
 779         /* FIXME: use iterator macros --RR */
 780         /* ... then go back and fix counters and names */
 781         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 782                 const struct xt_entry_target *t;
 783
 784                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 785                 if (copy_to_user(userptr + off
 786                                  + offsetof(struct arpt_entry, counters),
 787                                  &counters[num],
 788                                  sizeof(counters[num])) != 0) {
 789                         ret = -EFAULT;
 790                         goto free_counters;
 791                 }
 792
 793                 t = arpt_get_target_c(e);
 794                 if (copy_to_user(userptr + off + e->target_offset
 795                                  + offsetof(struct xt_entry_target,
 796                                             u.user.name),
 797                                  t->u.kernel.target->name,
 798                                  strlen(t->u.kernel.target->name)+1) != 0) {
 799                         ret = -EFAULT;
 800                         goto free_counters;
 801                 }
 802         }
 803
 804  free_counters:
 805         vfree(counters);
 806         return ret;
 807 }
 808
 809 #ifdef CONFIG_COMPAT
 810 static void compat_standard_from_user(void *dst, const void *src)
 811 {
 812         int v = *(compat_int_t *)src;
 813
 814         if (v > 0)
 815                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 816         memcpy(dst, &v, sizeof(v));
 817 }
 818
 819 static int compat_standard_to_user(void __user *dst, const void *src)
 820 {
 821         compat_int_t cv = *(int *)src;
 822
 823         if (cv > 0)
 824                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 825         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 826 }
 827
 828 static int compat_calc_entry(const struct arpt_entry *e,
 829                              const struct xt_table_info *info,
 830                              const void *base, struct xt_table_info *newinfo)
 831 {
 832         const struct xt_entry_target *t;
 833         unsigned int entry_offset;
 834         int off, i, ret;
 835
 836         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 837         entry_offset = (void *)e - base;
 838
 839         t = arpt_get_target_c(e);
 840         off += xt_compat_target_offset(t->u.kernel.target);
 841         newinfo->size -= off;
 842         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 843         if (ret)
 844                 return ret;
 845
 846         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 847                 if (info->hook_entry[i] &&
 848                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 849                         newinfo->hook_entry[i] -= off;
 850                 if (info->underflow[i] &&
 851                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 852                         newinfo->underflow[i] -= off;
 853         }
 854         return 0;
 855 }
 856
 857 static int compat_table_info(const struct xt_table_info *info,
 858                              struct xt_table_info *newinfo)
 859 {
 860         struct arpt_entry *iter;
 861         void *loc_cpu_entry;
 862         int ret;
 863
 864         if (!newinfo || !info)
 865                 return -EINVAL;
 866
 867         /* we dont care about newinfo->entries[] */
 868         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 869         newinfo->initial_entries = 0;
 870         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 871         xt_compat_init_offsets(NFPROTO_ARP, info->number);
 872         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 873                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 874                 if (ret != 0)
 875                         return ret;
 876         }
 877         return 0;
 878 }
 879 #endif
 880
 881 static int get_info(struct net *net, void __user *user,
 882                     const int *len, int compat)
 883 {
 884         char name[XT_TABLE_MAXNAMELEN];
 885         struct xt_table *t;
 886         int ret;
 887
 888         if (*len != sizeof(struct arpt_getinfo)) {
 889                 duprintf("length %u != %Zu\n", *len,
 890                          sizeof(struct arpt_getinfo));
 891                 return -EINVAL;
 892         }
 893
 894         if (copy_from_user(name, user, sizeof(name)) != 0)
 895                 return -EFAULT;
 896
 897         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 898 #ifdef CONFIG_COMPAT
 899         if (compat)
 900                 xt_compat_lock(NFPROTO_ARP);
 901 #endif
 902         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 903                                     "arptable_%s", name);
 904         if (t && !IS_ERR(t)) {
 905                 struct arpt_getinfo info;
 906                 const struct xt_table_info *private = t->private;
 907 #ifdef CONFIG_COMPAT
 908                 struct xt_table_info tmp;
 909
 910                 if (compat) {
 911                         ret = compat_table_info(private, &tmp);
 912                         xt_compat_flush_offsets(NFPROTO_ARP);
 913                         private = &tmp;
 914                 }
 915 #endif
 916                 memset(&info, 0, sizeof(info));
 917                 info.valid_hooks = t->valid_hooks;
 918                 memcpy(info.hook_entry, private->hook_entry,
 919                        sizeof(info.hook_entry));
 920                 memcpy(info.underflow, private->underflow,
 921                        sizeof(info.underflow));
 922                 info.num_entries = private->number;
 923                 info.size = private->size;
 924                 strcpy(info.name, name);
 925
 926                 if (copy_to_user(user, &info, *len) != 0)
 927                         ret = -EFAULT;
 928                 else
 929                         ret = 0;
 930                 xt_table_unlock(t);
 931                 module_put(t->me);
 932         } else
 933                 ret = t ? PTR_ERR(t) : -ENOENT;
 934 #ifdef CONFIG_COMPAT
 935         if (compat)
 936                 xt_compat_unlock(NFPROTO_ARP);
 937 #endif
 938         return ret;
 939 }
 940
 941 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 942                        const int *len)
 943 {
 944         int ret;
 945         struct arpt_get_entries get;
 946         struct xt_table *t;
 947
 948         if (*len < sizeof(get)) {
 949                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 950                 return -EINVAL;
 951         }
 952         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 953                 return -EFAULT;
 954         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 955                 duprintf("get_entries: %u != %Zu\n", *len,
 956                          sizeof(struct arpt_get_entries) + get.size);
 957                 return -EINVAL;
 958         }
 959
 960         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 961         if (t && !IS_ERR(t)) {
 962                 const struct xt_table_info *private = t->private;
 963
 964                 duprintf("t->private->number = %u\n",
 965                          private->number);
 966                 if (get.size == private->size)
 967                         ret = copy_entries_to_user(private->size,
 968                                                    t, uptr->entrytable);
 969                 else {
 970                         duprintf("get_entries: I've got %u not %u!\n",
 971                                  private->size, get.size);
 972                         ret = -EAGAIN;
 973                 }
 974                 module_put(t->me);
 975                 xt_table_unlock(t);
 976         } else
 977                 ret = t ? PTR_ERR(t) : -ENOENT;
 978
 979         return ret;
 980 }
 981
 982 static int __do_replace(struct net *net, const char *name,
 983                         unsigned int valid_hooks,
 984                         struct xt_table_info *newinfo,
 985                         unsigned int num_counters,
 986                         void __user *counters_ptr)
 987 {
 988         int ret;
 989         struct xt_table *t;
 990         struct xt_table_info *oldinfo;
 991         struct xt_counters *counters;
 992         void *loc_cpu_old_entry;
 993         struct arpt_entry *iter;
 994
 995         ret = 0;
 996         counters = vzalloc(num_counters * sizeof(struct xt_counters));
 997         if (!counters) {
 998                 ret = -ENOMEM;
 999                 goto out;
1000         }
1001
1002         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1003                                     "arptable_%s", name);
1004         if (!t || IS_ERR(t)) {
1005                 ret = t ? PTR_ERR(t) : -ENOENT;
1006                 goto free_newinfo_counters_untrans;
1007         }
1008
1009         /* You lied! */
1010         if (valid_hooks != t->valid_hooks) {
1011                 duprintf("Valid hook crap: %08X vs %08X\n",
1012                          valid_hooks, t->valid_hooks);
1013                 ret = -EINVAL;
1014                 goto put_module;
1015         }
1016
1017         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1018         if (!oldinfo)
1019                 goto put_module;
1020
1021         /* Update module usage count based on number of rules */
1022         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1023                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1024         if ((oldinfo->number > oldinfo->initial_entries) ||
1025             (newinfo->number <= oldinfo->initial_entries))
1026                 module_put(t->me);
1027         if ((oldinfo->number > oldinfo->initial_entries) &&
1028             (newinfo->number <= oldinfo->initial_entries))
1029                 module_put(t->me);
1030
1031         /* Get the old counters, and synchronize with replace */
1032         get_counters(oldinfo, counters);
1033
1034         /* Decrease module usage counts and free resource */
1035         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1036         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1037                 cleanup_entry(iter);
1038
1039         xt_free_table_info(oldinfo);
1040         if (copy_to_user(counters_ptr, counters,
1041                          sizeof(struct xt_counters) * num_counters) != 0)
1042                 ret = -EFAULT;
1043         vfree(counters);
1044         xt_table_unlock(t);
1045         return ret;
1046
1047  put_module:
1048         module_put(t->me);
1049         xt_table_unlock(t);
1050  free_newinfo_counters_untrans:
1051         vfree(counters);
1052  out:
1053         return ret;
1054 }
1055
1056 static int do_replace(struct net *net, const void __user *user,
1057                       unsigned int len)
1058 {
1059         int ret;
1060         struct arpt_replace tmp;
1061         struct xt_table_info *newinfo;
1062         void *loc_cpu_entry;
1063         struct arpt_entry *iter;
1064
1065         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1066                 return -EFAULT;
1067
1068         /* overflow check */
1069         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1070                 return -ENOMEM;
1071         tmp.name[sizeof(tmp.name)-1] = 0;
1072
1073         newinfo = xt_alloc_table_info(tmp.size);
1074         if (!newinfo)
1075                 return -ENOMEM;
1076
1077         /* choose the copy that is on our node/cpu */
1078         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1079         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1080                            tmp.size) != 0) {
1081                 ret = -EFAULT;
1082                 goto free_newinfo;
1083         }
1084
1085         ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1086         if (ret != 0)
1087                 goto free_newinfo;
1088
1089         duprintf("arp_tables: Translated table\n");
1090
1091         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1092                            tmp.num_counters, tmp.counters);
1093         if (ret)
1094                 goto free_newinfo_untrans;
1095         return 0;
1096
1097  free_newinfo_untrans:
1098         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1099                 cleanup_entry(iter);
1100  free_newinfo:
1101         xt_free_table_info(newinfo);
1102         return ret;
1103 }
1104
1105 static int do_add_counters(struct net *net, const void __user *user,
1106                            unsigned int len, int compat)
1107 {
1108         unsigned int i, curcpu;
1109         struct xt_counters_info tmp;
1110         struct xt_counters *paddc;
1111         unsigned int num_counters;
1112         const char *name;
1113         int size;
1114         void *ptmp;
1115         struct xt_table *t;
1116         const struct xt_table_info *private;
1117         int ret = 0;
1118         void *loc_cpu_entry;
1119         struct arpt_entry *iter;
1120         unsigned int addend;
1121 #ifdef CONFIG_COMPAT
1122         struct compat_xt_counters_info compat_tmp;
1123
1124         if (compat) {
1125                 ptmp = &compat_tmp;
1126                 size = sizeof(struct compat_xt_counters_info);
1127         } else
1128 #endif
1129         {
1130                 ptmp = &tmp;
1131                 size = sizeof(struct xt_counters_info);
1132         }
1133
1134         if (copy_from_user(ptmp, user, size) != 0)
1135                 return -EFAULT;
1136
1137 #ifdef CONFIG_COMPAT
1138         if (compat) {
1139                 num_counters = compat_tmp.num_counters;
1140                 name = compat_tmp.name;
1141         } else
1142 #endif
1143         {
1144                 num_counters = tmp.num_counters;
1145                 name = tmp.name;
1146         }
1147
1148         if (len != size + num_counters * sizeof(struct xt_counters))
1149                 return -EINVAL;
1150
1151         paddc = vmalloc(len - size);
1152         if (!paddc)
1153                 return -ENOMEM;
1154
1155         if (copy_from_user(paddc, user + size, len - size) != 0) {
1156                 ret = -EFAULT;
1157                 goto free;
1158         }
1159
1160         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1161         if (!t || IS_ERR(t)) {
1162                 ret = t ? PTR_ERR(t) : -ENOENT;
1163                 goto free;
1164         }
1165
1166         local_bh_disable();
1167         private = t->private;
1168         if (private->number != num_counters) {
1169                 ret = -EINVAL;
1170                 goto unlock_up_free;
1171         }
1172
1173         i = 0;
1174         /* Choose the copy that is on our node */
1175         curcpu = smp_processor_id();
1176         loc_cpu_entry = private->entries[curcpu];
1177         addend = xt_write_recseq_begin();
1178         xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1179                 ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1180                 ++i;
1181         }
1182         xt_write_recseq_end(addend);
1183  unlock_up_free:
1184         local_bh_enable();
1185         xt_table_unlock(t);
1186         module_put(t->me);
1187  free:
1188         vfree(paddc);
1189
1190         return ret;
1191 }
1192
1193 #ifdef CONFIG_COMPAT
1194 static inline void compat_release_entry(struct compat_arpt_entry *e)
1195 {
1196         struct xt_entry_target *t;
1197
1198         t = compat_arpt_get_target(e);
1199         module_put(t->u.kernel.target->me);
1200 }
1201
1202 static inline int
1203 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1204                                   struct xt_table_info *newinfo,
1205                                   unsigned int *size,
1206                                   const unsigned char *base,
1207                                   const unsigned char *limit,
1208                                   const unsigned int *hook_entries,
1209                                   const unsigned int *underflows,
1210                                   const char *name)
1211 {
1212         struct xt_entry_target *t;
1213         struct xt_target *target;
1214         unsigned int entry_offset;
1215         int ret, off, h;
1216
1217         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1218         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1219             (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1220                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1221                 return -EINVAL;
1222         }
1223
1224         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1225                              sizeof(struct compat_xt_entry_target)) {
1226                 duprintf("checking: element %p size %u\n",
1227                          e, e->next_offset);
1228                 return -EINVAL;
1229         }
1230
1231         /* For purposes of check_entry casting the compat entry is fine */
1232         ret = check_entry((struct arpt_entry *)e, name);
1233         if (ret)
1234                 return ret;
1235
1236         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1237         entry_offset = (void *)e - (void *)base;
1238
1239         t = compat_arpt_get_target(e);
1240         target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1241                                         t->u.user.revision);
1242         if (IS_ERR(target)) {
1243                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1244                          t->u.user.name);
1245                 ret = PTR_ERR(target);
1246                 goto out;
1247         }
1248         t->u.kernel.target = target;
1249
1250         off += xt_compat_target_offset(target);
1251         *size += off;
1252         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1253         if (ret)
1254                 goto release_target;
1255
1256         /* Check hooks & underflows */
1257         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1258                 if ((unsigned char *)e - base == hook_entries[h])
1259                         newinfo->hook_entry[h] = hook_entries[h];
1260                 if ((unsigned char *)e - base == underflows[h])
1261                         newinfo->underflow[h] = underflows[h];
1262         }
1263
1264         /* Clear counters and comefrom */
1265         memset(&e->counters, 0, sizeof(e->counters));
1266         e->comefrom = 0;
1267         return 0;
1268
1269 release_target:
1270         module_put(t->u.kernel.target->me);
1271 out:
1272         return ret;
1273 }
1274
1275 static int
1276 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1277                             unsigned int *size, const char *name,
1278                             struct xt_table_info *newinfo, unsigned char *base)
1279 {
1280         struct xt_entry_target *t;
1281         struct xt_target *target;
1282         struct arpt_entry *de;
1283         unsigned int origsize;
1284         int ret, h;
1285
1286         ret = 0;
1287         origsize = *size;
1288         de = (struct arpt_entry *)*dstptr;
1289         memcpy(de, e, sizeof(struct arpt_entry));
1290         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1291
1292         *dstptr += sizeof(struct arpt_entry);
1293         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1294
1295         de->target_offset = e->target_offset - (origsize - *size);
1296         t = compat_arpt_get_target(e);
1297         target = t->u.kernel.target;
1298         xt_compat_target_from_user(t, dstptr, size);
1299
1300         de->next_offset = e->next_offset - (origsize - *size);
1301         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1302                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1303                         newinfo->hook_entry[h] -= origsize - *size;
1304                 if ((unsigned char *)de - base < newinfo->underflow[h])
1305                         newinfo->underflow[h] -= origsize - *size;
1306         }
1307         return ret;
1308 }
1309
1310 static int translate_compat_table(const char *name,
1311                                   unsigned int valid_hooks,
1312                                   struct xt_table_info **pinfo,
1313                                   void **pentry0,
1314                                   unsigned int total_size,
1315                                   unsigned int number,
1316                                   unsigned int *hook_entries,
1317                                   unsigned int *underflows)
1318 {
1319         unsigned int i, j;
1320         struct xt_table_info *newinfo, *info;
1321         void *pos, *entry0, *entry1;
1322         struct compat_arpt_entry *iter0;
1323         struct arpt_entry *iter1;
1324         unsigned int size;
1325         int ret = 0;
1326
1327         info = *pinfo;
1328         entry0 = *pentry0;
1329         size = total_size;
1330         info->number = number;
1331
1332         /* Init all hooks to impossible value. */
1333         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1334                 info->hook_entry[i] = 0xFFFFFFFF;
1335                 info->underflow[i] = 0xFFFFFFFF;
1336         }
1337
1338         duprintf("translate_compat_table: size %u\n", info->size);
1339         j = 0;
1340         xt_compat_lock(NFPROTO_ARP);
1341         xt_compat_init_offsets(NFPROTO_ARP, number);
1342         /* Walk through entries, checking offsets. */
1343         xt_entry_foreach(iter0, entry0, total_size) {
1344                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1345                                                         entry0,
1346                                                         entry0 + total_size,
1347                                                         hook_entries,
1348                                                         underflows,
1349                                                         name);
1350                 if (ret != 0)
1351                         goto out_unlock;
1352                 ++j;
1353         }
1354
1355         ret = -EINVAL;
1356         if (j != number) {
1357                 duprintf("translate_compat_table: %u not %u entries\n",
1358                          j, number);
1359                 goto out_unlock;
1360         }
1361
1362         /* Check hooks all assigned */
1363         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1364                 /* Only hooks which are valid */
1365                 if (!(valid_hooks & (1 << i)))
1366                         continue;
1367                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1368                         duprintf("Invalid hook entry %u %u\n",
1369                                  i, hook_entries[i]);
1370                         goto out_unlock;
1371                 }
1372                 if (info->underflow[i] == 0xFFFFFFFF) {
1373                         duprintf("Invalid underflow %u %u\n",
1374                                  i, underflows[i]);
1375                         goto out_unlock;
1376                 }
1377         }
1378
1379         ret = -ENOMEM;
1380         newinfo = xt_alloc_table_info(size);
1381         if (!newinfo)
1382                 goto out_unlock;
1383
1384         newinfo->number = number;
1385         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1386                 newinfo->hook_entry[i] = info->hook_entry[i];
1387                 newinfo->underflow[i] = info->underflow[i];
1388         }
1389         entry1 = newinfo->entries[raw_smp_processor_id()];
1390         pos = entry1;
1391         size = total_size;
1392         xt_entry_foreach(iter0, entry0, total_size) {
1393                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1394                                                   name, newinfo, entry1);
1395                 if (ret != 0)
1396                         break;
1397         }
1398         xt_compat_flush_offsets(NFPROTO_ARP);
1399         xt_compat_unlock(NFPROTO_ARP);
1400         if (ret)
1401                 goto free_newinfo;
1402
1403         ret = -ELOOP;
1404         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1405                 goto free_newinfo;
1406
1407         i = 0;
1408         xt_entry_foreach(iter1, entry1, newinfo->size) {
1409                 ret = check_target(iter1, name);
1410                 if (ret != 0)
1411                         break;
1412                 ++i;
1413                 if (strcmp(arpt_get_target(iter1)->u.user.name,
1414                     XT_ERROR_TARGET) == 0)
1415                         ++newinfo->stacksize;
1416         }
1417         if (ret) {
1418                 /*
1419                  * The first i matches need cleanup_entry (calls ->destroy)
1420                  * because they had called ->check already. The other j-i
1421                  * entries need only release.
1422                  */
1423                 int skip = i;
1424                 j -= i;
1425                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1426                         if (skip-- > 0)
1427                                 continue;
1428                         if (j-- == 0)
1429                                 break;
1430                         compat_release_entry(iter0);
1431                 }
1432                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1433                         if (i-- == 0)
1434                                 break;
1435                         cleanup_entry(iter1);
1436                 }
1437                 xt_free_table_info(newinfo);
1438                 return ret;
1439         }
1440
1441         /* And one copy for every other CPU */
1442         for_each_possible_cpu(i)
1443                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1444                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1445
1446         *pinfo = newinfo;
1447         *pentry0 = entry1;
1448         xt_free_table_info(info);
1449         return 0;
1450
1451 free_newinfo:
1452         xt_free_table_info(newinfo);
1453 out:
1454         xt_entry_foreach(iter0, entry0, total_size) {
1455                 if (j-- == 0)
1456                         break;
1457                 compat_release_entry(iter0);
1458         }
1459         return ret;
1460 out_unlock:
1461         xt_compat_flush_offsets(NFPROTO_ARP);
1462         xt_compat_unlock(NFPROTO_ARP);
1463         goto out;
1464 }
1465
1466 struct compat_arpt_replace {
1467         char                            name[XT_TABLE_MAXNAMELEN];
1468         u32                             valid_hooks;
1469         u32                             num_entries;
1470         u32                             size;
1471         u32                             hook_entry[NF_ARP_NUMHOOKS];
1472         u32                             underflow[NF_ARP_NUMHOOKS];
1473         u32                             num_counters;
1474         compat_uptr_t                   counters;
1475         struct compat_arpt_entry        entries[0];
1476 };
1477
1478 static int compat_do_replace(struct net *net, void __user *user,
1479                              unsigned int len)
1480 {
1481         int ret;
1482         struct compat_arpt_replace tmp;
1483         struct xt_table_info *newinfo;
1484         void *loc_cpu_entry;
1485         struct arpt_entry *iter;
1486
1487         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1488                 return -EFAULT;
1489
1490         /* overflow check */
1491         if (tmp.size >= INT_MAX / num_possible_cpus())
1492                 return -ENOMEM;
1493         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1494                 return -ENOMEM;
1495         tmp.name[sizeof(tmp.name)-1] = 0;
1496
1497         newinfo = xt_alloc_table_info(tmp.size);
1498         if (!newinfo)
1499                 return -ENOMEM;
1500
1501         /* choose the copy that is on our node/cpu */
1502         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1503         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1504                 ret = -EFAULT;
1505                 goto free_newinfo;
1506         }
1507
1508         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1509                                      &newinfo, &loc_cpu_entry, tmp.size,
1510                                      tmp.num_entries, tmp.hook_entry,
1511                                      tmp.underflow);
1512         if (ret != 0)
1513                 goto free_newinfo;
1514
1515         duprintf("compat_do_replace: Translated table\n");
1516
1517         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1518                            tmp.num_counters, compat_ptr(tmp.counters));
1519         if (ret)
1520                 goto free_newinfo_untrans;
1521         return 0;
1522
1523  free_newinfo_untrans:
1524         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1525                 cleanup_entry(iter);
1526  free_newinfo:
1527         xt_free_table_info(newinfo);
1528         return ret;
1529 }
1530
1531 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1532                                   unsigned int len)
1533 {
1534         int ret;
1535
1536         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1537                 return -EPERM;
1538
1539         switch (cmd) {
1540         case ARPT_SO_SET_REPLACE:
1541                 ret = compat_do_replace(sock_net(sk), user, len);
1542                 break;
1543
1544         case ARPT_SO_SET_ADD_COUNTERS:
1545                 ret = do_add_counters(sock_net(sk), user, len, 1);
1546                 break;
1547
1548         default:
1549                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1550                 ret = -EINVAL;
1551         }
1552
1553         return ret;
1554 }
1555
1556 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1557                                      compat_uint_t *size,
1558                                      struct xt_counters *counters,
1559                                      unsigned int i)
1560 {
1561         struct xt_entry_target *t;
1562         struct compat_arpt_entry __user *ce;
1563         u_int16_t target_offset, next_offset;
1564         compat_uint_t origsize;
1565         int ret;
1566
1567         origsize = *size;
1568         ce = (struct compat_arpt_entry __user *)*dstptr;
1569         if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1570             copy_to_user(&ce->counters, &counters[i],
1571             sizeof(counters[i])) != 0)
1572                 return -EFAULT;
1573
1574         *dstptr += sizeof(struct compat_arpt_entry);
1575         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1576
1577         target_offset = e->target_offset - (origsize - *size);
1578
1579         t = arpt_get_target(e);
1580         ret = xt_compat_target_to_user(t, dstptr, size);
1581         if (ret)
1582                 return ret;
1583         next_offset = e->next_offset - (origsize - *size);
1584         if (put_user(target_offset, &ce->target_offset) != 0 ||
1585             put_user(next_offset, &ce->next_offset) != 0)
1586                 return -EFAULT;
1587         return 0;
1588 }
1589
1590 static int compat_copy_entries_to_user(unsigned int total_size,
1591                                        struct xt_table *table,
1592                                        void __user *userptr)
1593 {
1594         struct xt_counters *counters;
1595         const struct xt_table_info *private = table->private;
1596         void __user *pos;
1597         unsigned int size;
1598         int ret = 0;
1599         void *loc_cpu_entry;
1600         unsigned int i = 0;
1601         struct arpt_entry *iter;
1602
1603         counters = alloc_counters(table);
1604         if (IS_ERR(counters))
1605                 return PTR_ERR(counters);
1606
1607         /* choose the copy on our node/cpu */
1608         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1609         pos = userptr;
1610         size = total_size;
1611         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1612                 ret = compat_copy_entry_to_user(iter, &pos,
1613                                                 &size, counters, i++);
1614                 if (ret != 0)
1615                         break;
1616         }
1617         vfree(counters);
1618         return ret;
1619 }
1620
1621 struct compat_arpt_get_entries {
1622         char name[XT_TABLE_MAXNAMELEN];
1623         compat_uint_t size;
1624         struct compat_arpt_entry entrytable[0];
1625 };
1626
1627 static int compat_get_entries(struct net *net,
1628                               struct compat_arpt_get_entries __user *uptr,
1629                               int *len)
1630 {
1631         int ret;
1632         struct compat_arpt_get_entries get;
1633         struct xt_table *t;
1634
1635         if (*len < sizeof(get)) {
1636                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1637                 return -EINVAL;
1638         }
1639         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1640                 return -EFAULT;
1641         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1642                 duprintf("compat_get_entries: %u != %zu\n",
1643                          *len, sizeof(get) + get.size);
1644                 return -EINVAL;
1645         }
1646
1647         xt_compat_lock(NFPROTO_ARP);
1648         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1649         if (t && !IS_ERR(t)) {
1650                 const struct xt_table_info *private = t->private;
1651                 struct xt_table_info info;
1652
1653                 duprintf("t->private->number = %u\n", private->number);
1654                 ret = compat_table_info(private, &info);
1655                 if (!ret && get.size == info.size) {
1656                         ret = compat_copy_entries_to_user(private->size,
1657                                                           t, uptr->entrytable);
1658                 } else if (!ret) {
1659                         duprintf("compat_get_entries: I've got %u not %u!\n",
1660                                  private->size, get.size);
1661                         ret = -EAGAIN;
1662                 }
1663                 xt_compat_flush_offsets(NFPROTO_ARP);
1664                 module_put(t->me);
1665                 xt_table_unlock(t);
1666         } else
1667                 ret = t ? PTR_ERR(t) : -ENOENT;
1668
1669         xt_compat_unlock(NFPROTO_ARP);
1670         return ret;
1671 }
1672
1673 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1674
1675 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1676                                   int *len)
1677 {
1678         int ret;
1679
1680         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1681                 return -EPERM;
1682
1683         switch (cmd) {
1684         case ARPT_SO_GET_INFO:
1685                 ret = get_info(sock_net(sk), user, len, 1);
1686                 break;
1687         case ARPT_SO_GET_ENTRIES:
1688                 ret = compat_get_entries(sock_net(sk), user, len);
1689                 break;
1690         default:
1691                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1692         }
1693         return ret;
1694 }
1695 #endif
1696
1697 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1698 {
1699         int ret;
1700
1701         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1702                 return -EPERM;
1703
1704         switch (cmd) {
1705         case ARPT_SO_SET_REPLACE:
1706                 ret = do_replace(sock_net(sk), user, len);
1707                 break;
1708
1709         case ARPT_SO_SET_ADD_COUNTERS:
1710                 ret = do_add_counters(sock_net(sk), user, len, 0);
1711                 break;
1712
1713         default:
1714                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1715                 ret = -EINVAL;
1716         }
1717
1718         return ret;
1719 }
1720
1721 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1722 {
1723         int ret;
1724
1725         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1726                 return -EPERM;
1727
1728         switch (cmd) {
1729         case ARPT_SO_GET_INFO:
1730                 ret = get_info(sock_net(sk), user, len, 0);
1731                 break;
1732
1733         case ARPT_SO_GET_ENTRIES:
1734                 ret = get_entries(sock_net(sk), user, len);
1735                 break;
1736
1737         case ARPT_SO_GET_REVISION_TARGET: {
1738                 struct xt_get_revision rev;
1739
1740                 if (*len != sizeof(rev)) {
1741                         ret = -EINVAL;
1742                         break;
1743                 }
1744                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1745                         ret = -EFAULT;
1746                         break;
1747                 }
1748                 rev.name[sizeof(rev.name)-1] = 0;
1749
1750                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1751                                                          rev.revision, 1, &ret),
1752                                         "arpt_%s", rev.name);
1753                 break;
1754         }
1755
1756         default:
1757                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1758                 ret = -EINVAL;
1759         }
1760
1761         return ret;
1762 }
1763
1764 struct xt_table *arpt_register_table(struct net *net,
1765                                      const struct xt_table *table,
1766                                      const struct arpt_replace *repl)
1767 {
1768         int ret;
1769         struct xt_table_info *newinfo;
1770         struct xt_table_info bootstrap = {0};
1771         void *loc_cpu_entry;
1772         struct xt_table *new_table;
1773
1774         newinfo = xt_alloc_table_info(repl->size);
1775         if (!newinfo) {
1776                 ret = -ENOMEM;
1777                 goto out;
1778         }
1779
1780         /* choose the copy on our node/cpu */
1781         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1782         memcpy(loc_cpu_entry, repl->entries, repl->size);
1783
1784         ret = translate_table(newinfo, loc_cpu_entry, repl);
1785         duprintf("arpt_register_table: translate table gives %d\n", ret);
1786         if (ret != 0)
1787                 goto out_free;
1788
1789         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1790         if (IS_ERR(new_table)) {
1791                 ret = PTR_ERR(new_table);
1792                 goto out_free;
1793         }
1794         return new_table;
1795
1796 out_free:
1797         xt_free_table_info(newinfo);
1798 out:
1799         return ERR_PTR(ret);
1800 }
1801
1802 void arpt_unregister_table(struct xt_table *table)
1803 {
1804         struct xt_table_info *private;
1805         void *loc_cpu_entry;
1806         struct module *table_owner = table->me;
1807         struct arpt_entry *iter;
1808
1809         private = xt_unregister_table(table);
1810
1811         /* Decrease module usage counts and free resources */
1812         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1813         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1814                 cleanup_entry(iter);
1815         if (private->number > private->initial_entries)
1816                 module_put(table_owner);
1817         xt_free_table_info(private);
1818 }
1819
1820 /* The built-in targets: standard (NULL) and error. */
1821 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1822         {
1823                 .name             = XT_STANDARD_TARGET,
1824                 .targetsize       = sizeof(int),
1825                 .family           = NFPROTO_ARP,
1826 #ifdef CONFIG_COMPAT
1827                 .compatsize       = sizeof(compat_int_t),
1828                 .compat_from_user = compat_standard_from_user,
1829                 .compat_to_user   = compat_standard_to_user,
1830 #endif
1831         },
1832         {
1833                 .name             = XT_ERROR_TARGET,
1834                 .target           = arpt_error,
1835                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
1836                 .family           = NFPROTO_ARP,
1837         },
1838 };
1839
1840 static struct nf_sockopt_ops arpt_sockopts = {
1841         .pf             = PF_INET,
1842         .set_optmin     = ARPT_BASE_CTL,
1843         .set_optmax     = ARPT_SO_SET_MAX+1,
1844         .set            = do_arpt_set_ctl,
1845 #ifdef CONFIG_COMPAT
1846         .compat_set     = compat_do_arpt_set_ctl,
1847 #endif
1848         .get_optmin     = ARPT_BASE_CTL,
1849         .get_optmax     = ARPT_SO_GET_MAX+1,
1850         .get            = do_arpt_get_ctl,
1851 #ifdef CONFIG_COMPAT
1852         .compat_get     = compat_do_arpt_get_ctl,
1853 #endif
1854         .owner          = THIS_MODULE,
1855 };
1856
1857 static int __net_init arp_tables_net_init(struct net *net)
1858 {
1859         return xt_proto_init(net, NFPROTO_ARP);
1860 }
1861
1862 static void __net_exit arp_tables_net_exit(struct net *net)
1863 {
1864         xt_proto_fini(net, NFPROTO_ARP);
1865 }
1866
1867 static struct pernet_operations arp_tables_net_ops = {
1868         .init = arp_tables_net_init,
1869         .exit = arp_tables_net_exit,
1870 };
1871
1872 static int __init arp_tables_init(void)
1873 {
1874         int ret;
1875
1876         ret = register_pernet_subsys(&arp_tables_net_ops);
1877         if (ret < 0)
1878                 goto err1;
1879
1880         /* No one else will be downing sem now, so we won't sleep */
1881         ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1882         if (ret < 0)
1883                 goto err2;
1884
1885         /* Register setsockopt */
1886         ret = nf_register_sockopt(&arpt_sockopts);
1887         if (ret < 0)
1888                 goto err4;
1889
1890         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1891         return 0;
1892
1893 err4:
1894         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1895 err2:
1896         unregister_pernet_subsys(&arp_tables_net_ops);
1897 err1:
1898         return ret;
1899 }
1900
1901 static void __exit arp_tables_fini(void)
1902 {
1903         nf_unregister_sockopt(&arpt_sockopts);
1904         xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1905         unregister_pernet_subsys(&arp_tables_net_ops);
1906 }
1907
1908 EXPORT_SYMBOL(arpt_register_table);
1909 EXPORT_SYMBOL(arpt_unregister_table);
1910 EXPORT_SYMBOL(arpt_do_table);
1911
1912 module_init(arp_tables_init);
1913 module_exit(arp_tables_fini);