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   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
  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
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  33 MODULE_DESCRIPTION("arptables core");
  34
  35 /*#define DEBUG_ARP_TABLES*/
  36 /*#define DEBUG_ARP_TABLES_USER*/
  37
  38 #ifdef DEBUG_ARP_TABLES
  39 #define dprintf(format, args...)  printk(format , ## args)
  40 #else
  41 #define dprintf(format, args...)
  42 #endif
  43
  44 #ifdef DEBUG_ARP_TABLES_USER
  45 #define duprintf(format, args...) printk(format , ## args)
  46 #else
  47 #define duprintf(format, args...)
  48 #endif
  49
  50 #ifdef CONFIG_NETFILTER_DEBUG
  51 #define ARP_NF_ASSERT(x)                                        \
  52 do {                                                            \
  53         if (!(x))                                               \
  54                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  55                        __func__, __FILE__, __LINE__);   \
  56 } while(0)
  57 #else
  58 #define ARP_NF_ASSERT(x)
  59 #endif
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       const char *hdr_addr, int len)
  63 {
  64         int i, ret;
  65
  66         if (len > ARPT_DEV_ADDR_LEN_MAX)
  67                 len = ARPT_DEV_ADDR_LEN_MAX;
  68
  69         ret = 0;
  70         for (i = 0; i < len; i++)
  71                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  72
  73         return (ret != 0);
  74 }
  75
  76 /*
  77  * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  78  * Some arches dont care, unrolling the loop is a win on them.
  79  * For other arches, we only have a 16bit alignement.
  80  */
  81 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  82 {
  83 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  84         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  85 #else
  86         unsigned long ret = 0;
  87         const u16 *a = (const u16 *)_a;
  88         const u16 *b = (const u16 *)_b;
  89         const u16 *mask = (const u16 *)_mask;
  90         int i;
  91
  92         for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  93                 ret |= (a[i] ^ b[i]) & mask[i];
  94 #endif
  95         return ret;
  96 }
  97
  98 /* Returns whether packet matches rule or not. */
  99 static inline int arp_packet_match(const struct arphdr *arphdr,
 100                                    struct net_device *dev,
 101                                    const char *indev,
 102                                    const char *outdev,
 103                                    const struct arpt_arp *arpinfo)
 104 {
 105         const char *arpptr = (char *)(arphdr + 1);
 106         const char *src_devaddr, *tgt_devaddr;
 107         __be32 src_ipaddr, tgt_ipaddr;
 108         long ret;
 109
 110 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 111
 112         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 113                   ARPT_INV_ARPOP)) {
 114                 dprintf("ARP operation field mismatch.\n");
 115                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 116                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 117                 return 0;
 118         }
 119
 120         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 121                   ARPT_INV_ARPHRD)) {
 122                 dprintf("ARP hardware address format mismatch.\n");
 123                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 124                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 125                 return 0;
 126         }
 127
 128         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 129                   ARPT_INV_ARPPRO)) {
 130                 dprintf("ARP protocol address format mismatch.\n");
 131                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 132                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 133                 return 0;
 134         }
 135
 136         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 137                   ARPT_INV_ARPHLN)) {
 138                 dprintf("ARP hardware address length mismatch.\n");
 139                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 140                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 141                 return 0;
 142         }
 143
 144         src_devaddr = arpptr;
 145         arpptr += dev->addr_len;
 146         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 147         arpptr += sizeof(u32);
 148         tgt_devaddr = arpptr;
 149         arpptr += dev->addr_len;
 150         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 151
 152         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 153                   ARPT_INV_SRCDEVADDR) ||
 154             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 155                   ARPT_INV_TGTDEVADDR)) {
 156                 dprintf("Source or target device address mismatch.\n");
 157
 158                 return 0;
 159         }
 160
 161         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 162                   ARPT_INV_SRCIP) ||
 163             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 164                   ARPT_INV_TGTIP)) {
 165                 dprintf("Source or target IP address mismatch.\n");
 166
 167                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 168                         &src_ipaddr,
 169                         &arpinfo->smsk.s_addr,
 170                         &arpinfo->src.s_addr,
 171                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 172                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 173                         &tgt_ipaddr,
 174                         &arpinfo->tmsk.s_addr,
 175                         &arpinfo->tgt.s_addr,
 176                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 177                 return 0;
 178         }
 179
 180         /* Look for ifname matches.  */
 181         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 182
 183         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 184                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 185                         indev, arpinfo->iniface,
 186                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 187                 return 0;
 188         }
 189
 190         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 191
 192         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 193                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 194                         outdev, arpinfo->outiface,
 195                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 196                 return 0;
 197         }
 198
 199         return 1;
 200 #undef FWINV
 201 }
 202
 203 static inline int arp_checkentry(const struct arpt_arp *arp)
 204 {
 205         if (arp->flags & ~ARPT_F_MASK) {
 206                 duprintf("Unknown flag bits set: %08X\n",
 207                          arp->flags & ~ARPT_F_MASK);
 208                 return 0;
 209         }
 210         if (arp->invflags & ~ARPT_INV_MASK) {
 211                 duprintf("Unknown invflag bits set: %08X\n",
 212                          arp->invflags & ~ARPT_INV_MASK);
 213                 return 0;
 214         }
 215
 216         return 1;
 217 }
 218
 219 static unsigned int
 220 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 221 {
 222         if (net_ratelimit())
 223                 printk("arp_tables: error: '%s'\n",
 224                        (const char *)par->targinfo);
 225
 226         return NF_DROP;
 227 }
 228
 229 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 230 {
 231         return (struct arpt_entry *)(base + offset);
 232 }
 233
 234 static inline __pure
 235 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 236 {
 237         return (void *)entry + entry->next_offset;
 238 }
 239
 240 unsigned int arpt_do_table(struct sk_buff *skb,
 241                            unsigned int hook,
 242                            const struct net_device *in,
 243                            const struct net_device *out,
 244                            struct xt_table *table)
 245 {
 246         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 247         unsigned int verdict = NF_DROP;
 248         const struct arphdr *arp;
 249         bool hotdrop = false;
 250         struct arpt_entry *e, *back;
 251         const char *indev, *outdev;
 252         void *table_base;
 253         const struct xt_table_info *private;
 254         struct xt_target_param tgpar;
 255
 256         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 257                 return NF_DROP;
 258
 259         indev = in ? in->name : nulldevname;
 260         outdev = out ? out->name : nulldevname;
 261
 262         xt_info_rdlock_bh();
 263         private = table->private;
 264         table_base = private->entries[smp_processor_id()];
 265
 266         e = get_entry(table_base, private->hook_entry[hook]);
 267         back = get_entry(table_base, private->underflow[hook]);
 268
 269         tgpar.in      = in;
 270         tgpar.out     = out;
 271         tgpar.hooknum = hook;
 272         tgpar.family  = NFPROTO_ARP;
 273
 274         arp = arp_hdr(skb);
 275         do {
 276                 struct arpt_entry_target *t;
 277                 int hdr_len;
 278
 279                 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 280                         e = arpt_next_entry(e);
 281                         continue;
 282                 }
 283
 284                 hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 285                         (2 * skb->dev->addr_len);
 286                 ADD_COUNTER(e->counters, hdr_len, 1);
 287
 288                 t = arpt_get_target(e);
 289
 290                 /* Standard target? */
 291                 if (!t->u.kernel.target->target) {
 292                         int v;
 293
 294                         v = ((struct arpt_standard_target *)t)->verdict;
 295                         if (v < 0) {
 296                                 /* Pop from stack? */
 297                                 if (v != ARPT_RETURN) {
 298                                         verdict = (unsigned)(-v) - 1;
 299                                         break;
 300                                 }
 301                                 e = back;
 302                                 back = get_entry(table_base, back->comefrom);
 303                                 continue;
 304                         }
 305                         if (table_base + v
 306                             != arpt_next_entry(e)) {
 307                                 /* Save old back ptr in next entry */
 308                                 struct arpt_entry *next = arpt_next_entry(e);
 309                                 next->comefrom = (void *)back - table_base;
 310
 311                                 /* set back pointer to next entry */
 312                                 back = next;
 313                         }
 314
 315                         e = get_entry(table_base, v);
 316                 } else {
 317                         /* Targets which reenter must return
 318                          * abs. verdicts
 319                          */
 320                         tgpar.target   = t->u.kernel.target;
 321                         tgpar.targinfo = t->data;
 322                         verdict = t->u.kernel.target->target(skb, &tgpar);
 323
 324                         /* Target might have changed stuff. */
 325                         arp = arp_hdr(skb);
 326
 327                         if (verdict == ARPT_CONTINUE)
 328                                 e = arpt_next_entry(e);
 329                         else
 330                                 /* Verdict */
 331                                 break;
 332                 }
 333         } while (!hotdrop);
 334         xt_info_rdunlock_bh();
 335
 336         if (hotdrop)
 337                 return NF_DROP;
 338         else
 339                 return verdict;
 340 }
 341
 342 /* All zeroes == unconditional rule. */
 343 static inline int unconditional(const struct arpt_arp *arp)
 344 {
 345         unsigned int i;
 346
 347         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 348                 if (((__u32 *)arp)[i])
 349                         return 0;
 350
 351         return 1;
 352 }
 353
 354 /* Figures out from what hook each rule can be called: returns 0 if
 355  * there are loops.  Puts hook bitmask in comefrom.
 356  */
 357 static int mark_source_chains(struct xt_table_info *newinfo,
 358                               unsigned int valid_hooks, void *entry0)
 359 {
 360         unsigned int hook;
 361
 362         /* No recursion; use packet counter to save back ptrs (reset
 363          * to 0 as we leave), and comefrom to save source hook bitmask.
 364          */
 365         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 366                 unsigned int pos = newinfo->hook_entry[hook];
 367                 struct arpt_entry *e
 368                         = (struct arpt_entry *)(entry0 + pos);
 369
 370                 if (!(valid_hooks & (1 << hook)))
 371                         continue;
 372
 373                 /* Set initial back pointer. */
 374                 e->counters.pcnt = pos;
 375
 376                 for (;;) {
 377                         const struct arpt_standard_target *t
 378                                 = (void *)arpt_get_target(e);
 379                         int visited = e->comefrom & (1 << hook);
 380
 381                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 382                                 printk("arptables: loop hook %u pos %u %08X.\n",
 383                                        hook, pos, e->comefrom);
 384                                 return 0;
 385                         }
 386                         e->comefrom
 387                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 388
 389                         /* Unconditional return/END. */
 390                         if ((e->target_offset == sizeof(struct arpt_entry)
 391                             && (strcmp(t->target.u.user.name,
 392                                        ARPT_STANDARD_TARGET) == 0)
 393                             && t->verdict < 0
 394                             && unconditional(&e->arp)) || visited) {
 395                                 unsigned int oldpos, size;
 396
 397                                 if ((strcmp(t->target.u.user.name,
 398                                             ARPT_STANDARD_TARGET) == 0) &&
 399                                     t->verdict < -NF_MAX_VERDICT - 1) {
 400                                         duprintf("mark_source_chains: bad "
 401                                                 "negative verdict (%i)\n",
 402                                                                 t->verdict);
 403                                         return 0;
 404                                 }
 405
 406                                 /* Return: backtrack through the last
 407                                  * big jump.
 408                                  */
 409                                 do {
 410                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 411                                         oldpos = pos;
 412                                         pos = e->counters.pcnt;
 413                                         e->counters.pcnt = 0;
 414
 415                                         /* We're at the start. */
 416                                         if (pos == oldpos)
 417                                                 goto next;
 418
 419                                         e = (struct arpt_entry *)
 420                                                 (entry0 + pos);
 421                                 } while (oldpos == pos + e->next_offset);
 422
 423                                 /* Move along one */
 424                                 size = e->next_offset;
 425                                 e = (struct arpt_entry *)
 426                                         (entry0 + pos + size);
 427                                 e->counters.pcnt = pos;
 428                                 pos += size;
 429                         } else {
 430                                 int newpos = t->verdict;
 431
 432                                 if (strcmp(t->target.u.user.name,
 433                                            ARPT_STANDARD_TARGET) == 0
 434                                     && newpos >= 0) {
 435                                         if (newpos > newinfo->size -
 436                                                 sizeof(struct arpt_entry)) {
 437                                                 duprintf("mark_source_chains: "
 438                                                         "bad verdict (%i)\n",
 439                                                                 newpos);
 440                                                 return 0;
 441                                         }
 442
 443                                         /* This a jump; chase it. */
 444                                         duprintf("Jump rule %u -> %u\n",
 445                                                  pos, newpos);
 446                                 } else {
 447                                         /* ... this is a fallthru */
 448                                         newpos = pos + e->next_offset;
 449                                 }
 450                                 e = (struct arpt_entry *)
 451                                         (entry0 + newpos);
 452                                 e->counters.pcnt = pos;
 453                                 pos = newpos;
 454                         }
 455                 }
 456                 next:
 457                 duprintf("Finished chain %u\n", hook);
 458         }
 459         return 1;
 460 }
 461
 462 static inline int check_entry(struct arpt_entry *e, const char *name)
 463 {
 464         const struct arpt_entry_target *t;
 465
 466         if (!arp_checkentry(&e->arp)) {
 467                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 468                 return -EINVAL;
 469         }
 470
 471         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 472                 return -EINVAL;
 473
 474         t = arpt_get_target(e);
 475         if (e->target_offset + t->u.target_size > e->next_offset)
 476                 return -EINVAL;
 477
 478         return 0;
 479 }
 480
 481 static inline int check_target(struct arpt_entry *e, const char *name)
 482 {
 483         struct arpt_entry_target *t = arpt_get_target(e);
 484         int ret;
 485         struct xt_tgchk_param par = {
 486                 .table     = name,
 487                 .entryinfo = e,
 488                 .target    = t->u.kernel.target,
 489                 .targinfo  = t->data,
 490                 .hook_mask = e->comefrom,
 491                 .family    = NFPROTO_ARP,
 492         };
 493
 494         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 495         if (ret < 0) {
 496                 duprintf("arp_tables: check failed for `%s'.\n",
 497                          t->u.kernel.target->name);
 498                 return ret;
 499         }
 500         return 0;
 501 }
 502
 503 static inline int
 504 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 505                  unsigned int *i)
 506 {
 507         struct arpt_entry_target *t;
 508         struct xt_target *target;
 509         int ret;
 510
 511         ret = check_entry(e, name);
 512         if (ret)
 513                 return ret;
 514
 515         t = arpt_get_target(e);
 516         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 517                                                         t->u.user.name,
 518                                                         t->u.user.revision),
 519                                          "arpt_%s", t->u.user.name);
 520         if (IS_ERR(target) || !target) {
 521                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 522                 ret = target ? PTR_ERR(target) : -ENOENT;
 523                 goto out;
 524         }
 525         t->u.kernel.target = target;
 526
 527         ret = check_target(e, name);
 528         if (ret)
 529                 goto err;
 530
 531         (*i)++;
 532         return 0;
 533 err:
 534         module_put(t->u.kernel.target->me);
 535 out:
 536         return ret;
 537 }
 538
 539 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 540                                              struct xt_table_info *newinfo,
 541                                              unsigned char *base,
 542                                              unsigned char *limit,
 543                                              const unsigned int *hook_entries,
 544                                              const unsigned int *underflows,
 545                                              unsigned int *i)
 546 {
 547         unsigned int h;
 548
 549         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 550             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 551                 duprintf("Bad offset %p\n", e);
 552                 return -EINVAL;
 553         }
 554
 555         if (e->next_offset
 556             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 557                 duprintf("checking: element %p size %u\n",
 558                          e, e->next_offset);
 559                 return -EINVAL;
 560         }
 561
 562         /* Check hooks & underflows */
 563         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 564                 if ((unsigned char *)e - base == hook_entries[h])
 565                         newinfo->hook_entry[h] = hook_entries[h];
 566                 if ((unsigned char *)e - base == underflows[h])
 567                         newinfo->underflow[h] = underflows[h];
 568         }
 569
 570         /* FIXME: underflows must be unconditional, standard verdicts
 571            < 0 (not ARPT_RETURN). --RR */
 572
 573         /* Clear counters and comefrom */
 574         e->counters = ((struct xt_counters) { 0, 0 });
 575         e->comefrom = 0;
 576
 577         (*i)++;
 578         return 0;
 579 }
 580
 581 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 582 {
 583         struct xt_tgdtor_param par;
 584         struct arpt_entry_target *t;
 585
 586         if (i && (*i)-- == 0)
 587                 return 1;
 588
 589         t = arpt_get_target(e);
 590         par.target   = t->u.kernel.target;
 591         par.targinfo = t->data;
 592         par.family   = NFPROTO_ARP;
 593         if (par.target->destroy != NULL)
 594                 par.target->destroy(&par);
 595         module_put(par.target->me);
 596         return 0;
 597 }
 598
 599 /* Checks and translates the user-supplied table segment (held in
 600  * newinfo).
 601  */
 602 static int translate_table(const char *name,
 603                            unsigned int valid_hooks,
 604                            struct xt_table_info *newinfo,
 605                            void *entry0,
 606                            unsigned int size,
 607                            unsigned int number,
 608                            const unsigned int *hook_entries,
 609                            const unsigned int *underflows)
 610 {
 611         unsigned int i;
 612         int ret;
 613
 614         newinfo->size = size;
 615         newinfo->number = number;
 616
 617         /* Init all hooks to impossible value. */
 618         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 619                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 620                 newinfo->underflow[i] = 0xFFFFFFFF;
 621         }
 622
 623         duprintf("translate_table: size %u\n", newinfo->size);
 624         i = 0;
 625
 626         /* Walk through entries, checking offsets. */
 627         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 628                                  check_entry_size_and_hooks,
 629                                  newinfo,
 630                                  entry0,
 631                                  entry0 + size,
 632                                  hook_entries, underflows, &i);
 633         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 634         if (ret != 0)
 635                 return ret;
 636
 637         if (i != number) {
 638                 duprintf("translate_table: %u not %u entries\n",
 639                          i, number);
 640                 return -EINVAL;
 641         }
 642
 643         /* Check hooks all assigned */
 644         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 645                 /* Only hooks which are valid */
 646                 if (!(valid_hooks & (1 << i)))
 647                         continue;
 648                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 649                         duprintf("Invalid hook entry %u %u\n",
 650                                  i, hook_entries[i]);
 651                         return -EINVAL;
 652                 }
 653                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 654                         duprintf("Invalid underflow %u %u\n",
 655                                  i, underflows[i]);
 656                         return -EINVAL;
 657                 }
 658         }
 659
 660         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 661                 duprintf("Looping hook\n");
 662                 return -ELOOP;
 663         }
 664
 665         /* Finally, each sanity check must pass */
 666         i = 0;
 667         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 668                                  find_check_entry, name, size, &i);
 669
 670         if (ret != 0) {
 671                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 672                                 cleanup_entry, &i);
 673                 return ret;
 674         }
 675
 676         /* And one copy for every other CPU */
 677         for_each_possible_cpu(i) {
 678                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 679                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 680         }
 681
 682         return ret;
 683 }
 684
 685 /* Gets counters. */
 686 static inline int add_entry_to_counter(const struct arpt_entry *e,
 687                                        struct xt_counters total[],
 688                                        unsigned int *i)
 689 {
 690         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 691
 692         (*i)++;
 693         return 0;
 694 }
 695
 696 static inline int set_entry_to_counter(const struct arpt_entry *e,
 697                                        struct xt_counters total[],
 698                                        unsigned int *i)
 699 {
 700         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 701
 702         (*i)++;
 703         return 0;
 704 }
 705
 706 static void get_counters(const struct xt_table_info *t,
 707                          struct xt_counters counters[])
 708 {
 709         unsigned int cpu;
 710         unsigned int i;
 711         unsigned int curcpu;
 712
 713         /* Instead of clearing (by a previous call to memset())
 714          * the counters and using adds, we set the counters
 715          * with data used by 'current' CPU
 716          *
 717          * Bottom half has to be disabled to prevent deadlock
 718          * if new softirq were to run and call ipt_do_table
 719          */
 720         local_bh_disable();
 721         curcpu = smp_processor_id();
 722
 723         i = 0;
 724         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 725                            t->size,
 726                            set_entry_to_counter,
 727                            counters,
 728                            &i);
 729
 730         for_each_possible_cpu(cpu) {
 731                 if (cpu == curcpu)
 732                         continue;
 733                 i = 0;
 734                 xt_info_wrlock(cpu);
 735                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 736                                    t->size,
 737                                    add_entry_to_counter,
 738                                    counters,
 739                                    &i);
 740                 xt_info_wrunlock(cpu);
 741         }
 742         local_bh_enable();
 743 }
 744
 745 static struct xt_counters *alloc_counters(struct xt_table *table)
 746 {
 747         unsigned int countersize;
 748         struct xt_counters *counters;
 749         struct xt_table_info *private = table->private;
 750
 751         /* We need atomic snapshot of counters: rest doesn't change
 752          * (other than comefrom, which userspace doesn't care
 753          * about).
 754          */
 755         countersize = sizeof(struct xt_counters) * private->number;
 756         counters = vmalloc_node(countersize, numa_node_id());
 757
 758         if (counters == NULL)
 759                 return ERR_PTR(-ENOMEM);
 760
 761         get_counters(private, counters);
 762
 763         return counters;
 764 }
 765
 766 static int copy_entries_to_user(unsigned int total_size,
 767                                 struct xt_table *table,
 768                                 void __user *userptr)
 769 {
 770         unsigned int off, num;
 771         struct arpt_entry *e;
 772         struct xt_counters *counters;
 773         struct xt_table_info *private = table->private;
 774         int ret = 0;
 775         void *loc_cpu_entry;
 776
 777         counters = alloc_counters(table);
 778         if (IS_ERR(counters))
 779                 return PTR_ERR(counters);
 780
 781         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 782         /* ... then copy entire thing ... */
 783         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 784                 ret = -EFAULT;
 785                 goto free_counters;
 786         }
 787
 788         /* FIXME: use iterator macros --RR */
 789         /* ... then go back and fix counters and names */
 790         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 791                 struct arpt_entry_target *t;
 792
 793                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 794                 if (copy_to_user(userptr + off
 795                                  + offsetof(struct arpt_entry, counters),
 796                                  &counters[num],
 797                                  sizeof(counters[num])) != 0) {
 798                         ret = -EFAULT;
 799                         goto free_counters;
 800                 }
 801
 802                 t = arpt_get_target(e);
 803                 if (copy_to_user(userptr + off + e->target_offset
 804                                  + offsetof(struct arpt_entry_target,
 805                                             u.user.name),
 806                                  t->u.kernel.target->name,
 807                                  strlen(t->u.kernel.target->name)+1) != 0) {
 808                         ret = -EFAULT;
 809                         goto free_counters;
 810                 }
 811         }
 812
 813  free_counters:
 814         vfree(counters);
 815         return ret;
 816 }
 817
 818 #ifdef CONFIG_COMPAT
 819 static void compat_standard_from_user(void *dst, void *src)
 820 {
 821         int v = *(compat_int_t *)src;
 822
 823         if (v > 0)
 824                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 825         memcpy(dst, &v, sizeof(v));
 826 }
 827
 828 static int compat_standard_to_user(void __user *dst, void *src)
 829 {
 830         compat_int_t cv = *(int *)src;
 831
 832         if (cv > 0)
 833                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 834         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 835 }
 836
 837 static int compat_calc_entry(struct arpt_entry *e,
 838                              const struct xt_table_info *info,
 839                              void *base, struct xt_table_info *newinfo)
 840 {
 841         struct arpt_entry_target *t;
 842         unsigned int entry_offset;
 843         int off, i, ret;
 844
 845         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 846         entry_offset = (void *)e - base;
 847
 848         t = arpt_get_target(e);
 849         off += xt_compat_target_offset(t->u.kernel.target);
 850         newinfo->size -= off;
 851         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 852         if (ret)
 853                 return ret;
 854
 855         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 856                 if (info->hook_entry[i] &&
 857                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 858                         newinfo->hook_entry[i] -= off;
 859                 if (info->underflow[i] &&
 860                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 861                         newinfo->underflow[i] -= off;
 862         }
 863         return 0;
 864 }
 865
 866 static int compat_table_info(const struct xt_table_info *info,
 867                              struct xt_table_info *newinfo)
 868 {
 869         void *loc_cpu_entry;
 870
 871         if (!newinfo || !info)
 872                 return -EINVAL;
 873
 874         /* we dont care about newinfo->entries[] */
 875         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 876         newinfo->initial_entries = 0;
 877         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 878         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 879                                   compat_calc_entry, info, loc_cpu_entry,
 880                                   newinfo);
 881 }
 882 #endif
 883
 884 static int get_info(struct net *net, void __user *user, int *len, int compat)
 885 {
 886         char name[ARPT_TABLE_MAXNAMELEN];
 887         struct xt_table *t;
 888         int ret;
 889
 890         if (*len != sizeof(struct arpt_getinfo)) {
 891                 duprintf("length %u != %Zu\n", *len,
 892                          sizeof(struct arpt_getinfo));
 893                 return -EINVAL;
 894         }
 895
 896         if (copy_from_user(name, user, sizeof(name)) != 0)
 897                 return -EFAULT;
 898
 899         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 900 #ifdef CONFIG_COMPAT
 901         if (compat)
 902                 xt_compat_lock(NFPROTO_ARP);
 903 #endif
 904         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 905                                     "arptable_%s", name);
 906         if (t && !IS_ERR(t)) {
 907                 struct arpt_getinfo info;
 908                 const struct xt_table_info *private = t->private;
 909
 910 #ifdef CONFIG_COMPAT
 911                 if (compat) {
 912                         struct xt_table_info tmp;
 913                         ret = compat_table_info(private, &tmp);
 914                         xt_compat_flush_offsets(NFPROTO_ARP);
 915                         private = &tmp;
 916                 }
 917 #endif
 918                 info.valid_hooks = t->valid_hooks;
 919                 memcpy(info.hook_entry, private->hook_entry,
 920                        sizeof(info.hook_entry));
 921                 memcpy(info.underflow, private->underflow,
 922                        sizeof(info.underflow));
 923                 info.num_entries = private->number;
 924                 info.size = private->size;
 925                 strcpy(info.name, name);
 926
 927                 if (copy_to_user(user, &info, *len) != 0)
 928                         ret = -EFAULT;
 929                 else
 930                         ret = 0;
 931                 xt_table_unlock(t);
 932                 module_put(t->me);
 933         } else
 934                 ret = t ? PTR_ERR(t) : -ENOENT;
 935 #ifdef CONFIG_COMPAT
 936         if (compat)
 937                 xt_compat_unlock(NFPROTO_ARP);
 938 #endif
 939         return ret;
 940 }
 941
 942 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 943                        int *len)
 944 {
 945         int ret;
 946         struct arpt_get_entries get;
 947         struct xt_table *t;
 948
 949         if (*len < sizeof(get)) {
 950                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 951                 return -EINVAL;
 952         }
 953         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 954                 return -EFAULT;
 955         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 956                 duprintf("get_entries: %u != %Zu\n", *len,
 957                          sizeof(struct arpt_get_entries) + get.size);
 958                 return -EINVAL;
 959         }
 960
 961         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 962         if (t && !IS_ERR(t)) {
 963                 const struct xt_table_info *private = t->private;
 964
 965                 duprintf("t->private->number = %u\n",
 966                          private->number);
 967                 if (get.size == private->size)
 968                         ret = copy_entries_to_user(private->size,
 969                                                    t, uptr->entrytable);
 970                 else {
 971                         duprintf("get_entries: I've got %u not %u!\n",
 972                                  private->size, get.size);
 973                         ret = -EAGAIN;
 974                 }
 975                 module_put(t->me);
 976                 xt_table_unlock(t);
 977         } else
 978                 ret = t ? PTR_ERR(t) : -ENOENT;
 979
 980         return ret;
 981 }
 982
 983 static int __do_replace(struct net *net, const char *name,
 984                         unsigned int valid_hooks,
 985                         struct xt_table_info *newinfo,
 986                         unsigned int num_counters,
 987                         void __user *counters_ptr)
 988 {
 989         int ret;
 990         struct xt_table *t;
 991         struct xt_table_info *oldinfo;
 992         struct xt_counters *counters;
 993         void *loc_cpu_old_entry;
 994
 995         ret = 0;
 996         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
 997                                 numa_node_id());
 998         if (!counters) {
 999                 ret = -ENOMEM;
1000                 goto out;
1001         }
1002
1003         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1004                                     "arptable_%s", name);
1005         if (!t || IS_ERR(t)) {
1006                 ret = t ? PTR_ERR(t) : -ENOENT;
1007                 goto free_newinfo_counters_untrans;
1008         }
1009
1010         /* You lied! */
1011         if (valid_hooks != t->valid_hooks) {
1012                 duprintf("Valid hook crap: %08X vs %08X\n",
1013                          valid_hooks, t->valid_hooks);
1014                 ret = -EINVAL;
1015                 goto put_module;
1016         }
1017
1018         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1019         if (!oldinfo)
1020                 goto put_module;
1021
1022         /* Update module usage count based on number of rules */
1023         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1024                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1025         if ((oldinfo->number > oldinfo->initial_entries) ||
1026             (newinfo->number <= oldinfo->initial_entries))
1027                 module_put(t->me);
1028         if ((oldinfo->number > oldinfo->initial_entries) &&
1029             (newinfo->number <= oldinfo->initial_entries))
1030                 module_put(t->me);
1031
1032         /* Get the old counters, and synchronize with replace */
1033         get_counters(oldinfo, counters);
1034
1035         /* Decrease module usage counts and free resource */
1036         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1037         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1038                            NULL);
1039
1040         xt_free_table_info(oldinfo);
1041         if (copy_to_user(counters_ptr, counters,
1042                          sizeof(struct xt_counters) * num_counters) != 0)
1043                 ret = -EFAULT;
1044         vfree(counters);
1045         xt_table_unlock(t);
1046         return ret;
1047
1048  put_module:
1049         module_put(t->me);
1050         xt_table_unlock(t);
1051  free_newinfo_counters_untrans:
1052         vfree(counters);
1053  out:
1054         return ret;
1055 }
1056
1057 static int do_replace(struct net *net, void __user *user, unsigned int len)
1058 {
1059         int ret;
1060         struct arpt_replace tmp;
1061         struct xt_table_info *newinfo;
1062         void *loc_cpu_entry;
1063
1064         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1065                 return -EFAULT;
1066
1067         /* overflow check */
1068         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1069                 return -ENOMEM;
1070
1071         newinfo = xt_alloc_table_info(tmp.size);
1072         if (!newinfo)
1073                 return -ENOMEM;
1074
1075         /* choose the copy that is on our node/cpu */
1076         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1077         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1078                            tmp.size) != 0) {
1079                 ret = -EFAULT;
1080                 goto free_newinfo;
1081         }
1082
1083         ret = translate_table(tmp.name, tmp.valid_hooks,
1084                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1085                               tmp.hook_entry, tmp.underflow);
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         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1099  free_newinfo:
1100         xt_free_table_info(newinfo);
1101         return ret;
1102 }
1103
1104 /* We're lazy, and add to the first CPU; overflow works its fey magic
1105  * and everything is OK. */
1106 static int
1107 add_counter_to_entry(struct arpt_entry *e,
1108                      const struct xt_counters addme[],
1109                      unsigned int *i)
1110 {
1111         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1112
1113         (*i)++;
1114         return 0;
1115 }
1116
1117 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1118                            int compat)
1119 {
1120         unsigned int i, curcpu;
1121         struct xt_counters_info tmp;
1122         struct xt_counters *paddc;
1123         unsigned int num_counters;
1124         const char *name;
1125         int size;
1126         void *ptmp;
1127         struct xt_table *t;
1128         const struct xt_table_info *private;
1129         int ret = 0;
1130         void *loc_cpu_entry;
1131 #ifdef CONFIG_COMPAT
1132         struct compat_xt_counters_info compat_tmp;
1133
1134         if (compat) {
1135                 ptmp = &compat_tmp;
1136                 size = sizeof(struct compat_xt_counters_info);
1137         } else
1138 #endif
1139         {
1140                 ptmp = &tmp;
1141                 size = sizeof(struct xt_counters_info);
1142         }
1143
1144         if (copy_from_user(ptmp, user, size) != 0)
1145                 return -EFAULT;
1146
1147 #ifdef CONFIG_COMPAT
1148         if (compat) {
1149                 num_counters = compat_tmp.num_counters;
1150                 name = compat_tmp.name;
1151         } else
1152 #endif
1153         {
1154                 num_counters = tmp.num_counters;
1155                 name = tmp.name;
1156         }
1157
1158         if (len != size + num_counters * sizeof(struct xt_counters))
1159                 return -EINVAL;
1160
1161         paddc = vmalloc_node(len - size, numa_node_id());
1162         if (!paddc)
1163                 return -ENOMEM;
1164
1165         if (copy_from_user(paddc, user + size, len - size) != 0) {
1166                 ret = -EFAULT;
1167                 goto free;
1168         }
1169
1170         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1171         if (!t || IS_ERR(t)) {
1172                 ret = t ? PTR_ERR(t) : -ENOENT;
1173                 goto free;
1174         }
1175
1176         local_bh_disable();
1177         private = t->private;
1178         if (private->number != num_counters) {
1179                 ret = -EINVAL;
1180                 goto unlock_up_free;
1181         }
1182
1183         i = 0;
1184         /* Choose the copy that is on our node */
1185         curcpu = smp_processor_id();
1186         loc_cpu_entry = private->entries[curcpu];
1187         xt_info_wrlock(curcpu);
1188         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1189                            private->size,
1190                            add_counter_to_entry,
1191                            paddc,
1192                            &i);
1193         xt_info_wrunlock(curcpu);
1194  unlock_up_free:
1195         local_bh_enable();
1196         xt_table_unlock(t);
1197         module_put(t->me);
1198  free:
1199         vfree(paddc);
1200
1201         return ret;
1202 }
1203
1204 #ifdef CONFIG_COMPAT
1205 static inline int
1206 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1207 {
1208         struct arpt_entry_target *t;
1209
1210         if (i && (*i)-- == 0)
1211                 return 1;
1212
1213         t = compat_arpt_get_target(e);
1214         module_put(t->u.kernel.target->me);
1215         return 0;
1216 }
1217
1218 static inline int
1219 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1220                                   struct xt_table_info *newinfo,
1221                                   unsigned int *size,
1222                                   unsigned char *base,
1223                                   unsigned char *limit,
1224                                   unsigned int *hook_entries,
1225                                   unsigned int *underflows,
1226                                   unsigned int *i,
1227                                   const char *name)
1228 {
1229         struct arpt_entry_target *t;
1230         struct xt_target *target;
1231         unsigned int entry_offset;
1232         int ret, off, h;
1233
1234         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1235         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1236             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1237                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1238                 return -EINVAL;
1239         }
1240
1241         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1242                              sizeof(struct compat_xt_entry_target)) {
1243                 duprintf("checking: element %p size %u\n",
1244                          e, e->next_offset);
1245                 return -EINVAL;
1246         }
1247
1248         /* For purposes of check_entry casting the compat entry is fine */
1249         ret = check_entry((struct arpt_entry *)e, name);
1250         if (ret)
1251                 return ret;
1252
1253         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1254         entry_offset = (void *)e - (void *)base;
1255
1256         t = compat_arpt_get_target(e);
1257         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1258                                                         t->u.user.name,
1259                                                         t->u.user.revision),
1260                                          "arpt_%s", t->u.user.name);
1261         if (IS_ERR(target) || !target) {
1262                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1263                          t->u.user.name);
1264                 ret = target ? PTR_ERR(target) : -ENOENT;
1265                 goto out;
1266         }
1267         t->u.kernel.target = target;
1268
1269         off += xt_compat_target_offset(target);
1270         *size += off;
1271         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1272         if (ret)
1273                 goto release_target;
1274
1275         /* Check hooks & underflows */
1276         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1277                 if ((unsigned char *)e - base == hook_entries[h])
1278                         newinfo->hook_entry[h] = hook_entries[h];
1279                 if ((unsigned char *)e - base == underflows[h])
1280                         newinfo->underflow[h] = underflows[h];
1281         }
1282
1283         /* Clear counters and comefrom */
1284         memset(&e->counters, 0, sizeof(e->counters));
1285         e->comefrom = 0;
1286
1287         (*i)++;
1288         return 0;
1289
1290 release_target:
1291         module_put(t->u.kernel.target->me);
1292 out:
1293         return ret;
1294 }
1295
1296 static int
1297 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1298                             unsigned int *size, const char *name,
1299                             struct xt_table_info *newinfo, unsigned char *base)
1300 {
1301         struct arpt_entry_target *t;
1302         struct xt_target *target;
1303         struct arpt_entry *de;
1304         unsigned int origsize;
1305         int ret, h;
1306
1307         ret = 0;
1308         origsize = *size;
1309         de = (struct arpt_entry *)*dstptr;
1310         memcpy(de, e, sizeof(struct arpt_entry));
1311         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1312
1313         *dstptr += sizeof(struct arpt_entry);
1314         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1315
1316         de->target_offset = e->target_offset - (origsize - *size);
1317         t = compat_arpt_get_target(e);
1318         target = t->u.kernel.target;
1319         xt_compat_target_from_user(t, dstptr, size);
1320
1321         de->next_offset = e->next_offset - (origsize - *size);
1322         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1323                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1324                         newinfo->hook_entry[h] -= origsize - *size;
1325                 if ((unsigned char *)de - base < newinfo->underflow[h])
1326                         newinfo->underflow[h] -= origsize - *size;
1327         }
1328         return ret;
1329 }
1330
1331 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1332                                      unsigned int *i)
1333 {
1334         int ret;
1335
1336         ret = check_target(e, name);
1337         if (ret)
1338                 return ret;
1339
1340         (*i)++;
1341         return 0;
1342 }
1343
1344 static int translate_compat_table(const char *name,
1345                                   unsigned int valid_hooks,
1346                                   struct xt_table_info **pinfo,
1347                                   void **pentry0,
1348                                   unsigned int total_size,
1349                                   unsigned int number,
1350                                   unsigned int *hook_entries,
1351                                   unsigned int *underflows)
1352 {
1353         unsigned int i, j;
1354         struct xt_table_info *newinfo, *info;
1355         void *pos, *entry0, *entry1;
1356         unsigned int size;
1357         int ret;
1358
1359         info = *pinfo;
1360         entry0 = *pentry0;
1361         size = total_size;
1362         info->number = number;
1363
1364         /* Init all hooks to impossible value. */
1365         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1366                 info->hook_entry[i] = 0xFFFFFFFF;
1367                 info->underflow[i] = 0xFFFFFFFF;
1368         }
1369
1370         duprintf("translate_compat_table: size %u\n", info->size);
1371         j = 0;
1372         xt_compat_lock(NFPROTO_ARP);
1373         /* Walk through entries, checking offsets. */
1374         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1375                                         check_compat_entry_size_and_hooks,
1376                                         info, &size, entry0,
1377                                         entry0 + total_size,
1378                                         hook_entries, underflows, &j, name);
1379         if (ret != 0)
1380                 goto out_unlock;
1381
1382         ret = -EINVAL;
1383         if (j != number) {
1384                 duprintf("translate_compat_table: %u not %u entries\n",
1385                          j, number);
1386                 goto out_unlock;
1387         }
1388
1389         /* Check hooks all assigned */
1390         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1391                 /* Only hooks which are valid */
1392                 if (!(valid_hooks & (1 << i)))
1393                         continue;
1394                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1395                         duprintf("Invalid hook entry %u %u\n",
1396                                  i, hook_entries[i]);
1397                         goto out_unlock;
1398                 }
1399                 if (info->underflow[i] == 0xFFFFFFFF) {
1400                         duprintf("Invalid underflow %u %u\n",
1401                                  i, underflows[i]);
1402                         goto out_unlock;
1403                 }
1404         }
1405
1406         ret = -ENOMEM;
1407         newinfo = xt_alloc_table_info(size);
1408         if (!newinfo)
1409                 goto out_unlock;
1410
1411         newinfo->number = number;
1412         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1413                 newinfo->hook_entry[i] = info->hook_entry[i];
1414                 newinfo->underflow[i] = info->underflow[i];
1415         }
1416         entry1 = newinfo->entries[raw_smp_processor_id()];
1417         pos = entry1;
1418         size = total_size;
1419         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1420                                         compat_copy_entry_from_user,
1421                                         &pos, &size, name, newinfo, entry1);
1422         xt_compat_flush_offsets(NFPROTO_ARP);
1423         xt_compat_unlock(NFPROTO_ARP);
1424         if (ret)
1425                 goto free_newinfo;
1426
1427         ret = -ELOOP;
1428         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1429                 goto free_newinfo;
1430
1431         i = 0;
1432         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1433                                  name, &i);
1434         if (ret) {
1435                 j -= i;
1436                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1437                                                    compat_release_entry, &j);
1438                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1439                 xt_free_table_info(newinfo);
1440                 return ret;
1441         }
1442
1443         /* And one copy for every other CPU */
1444         for_each_possible_cpu(i)
1445                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1446                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1447
1448         *pinfo = newinfo;
1449         *pentry0 = entry1;
1450         xt_free_table_info(info);
1451         return 0;
1452
1453 free_newinfo:
1454         xt_free_table_info(newinfo);
1455 out:
1456         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1457         return ret;
1458 out_unlock:
1459         xt_compat_flush_offsets(NFPROTO_ARP);
1460         xt_compat_unlock(NFPROTO_ARP);
1461         goto out;
1462 }
1463
1464 struct compat_arpt_replace {
1465         char                            name[ARPT_TABLE_MAXNAMELEN];
1466         u32                             valid_hooks;
1467         u32                             num_entries;
1468         u32                             size;
1469         u32                             hook_entry[NF_ARP_NUMHOOKS];
1470         u32                             underflow[NF_ARP_NUMHOOKS];
1471         u32                             num_counters;
1472         compat_uptr_t                   counters;
1473         struct compat_arpt_entry        entries[0];
1474 };
1475
1476 static int compat_do_replace(struct net *net, void __user *user,
1477                              unsigned int len)
1478 {
1479         int ret;
1480         struct compat_arpt_replace tmp;
1481         struct xt_table_info *newinfo;
1482         void *loc_cpu_entry;
1483
1484         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1485                 return -EFAULT;
1486
1487         /* overflow check */
1488         if (tmp.size >= INT_MAX / num_possible_cpus())
1489                 return -ENOMEM;
1490         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1491                 return -ENOMEM;
1492
1493         newinfo = xt_alloc_table_info(tmp.size);
1494         if (!newinfo)
1495                 return -ENOMEM;
1496
1497         /* choose the copy that is on our node/cpu */
1498         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1499         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1500                 ret = -EFAULT;
1501                 goto free_newinfo;
1502         }
1503
1504         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1505                                      &newinfo, &loc_cpu_entry, tmp.size,
1506                                      tmp.num_entries, tmp.hook_entry,
1507                                      tmp.underflow);
1508         if (ret != 0)
1509                 goto free_newinfo;
1510
1511         duprintf("compat_do_replace: Translated table\n");
1512
1513         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1514                            tmp.num_counters, compat_ptr(tmp.counters));
1515         if (ret)
1516                 goto free_newinfo_untrans;
1517         return 0;
1518
1519  free_newinfo_untrans:
1520         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1521  free_newinfo:
1522         xt_free_table_info(newinfo);
1523         return ret;
1524 }
1525
1526 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1527                                   unsigned int len)
1528 {
1529         int ret;
1530
1531         if (!capable(CAP_NET_ADMIN))
1532                 return -EPERM;
1533
1534         switch (cmd) {
1535         case ARPT_SO_SET_REPLACE:
1536                 ret = compat_do_replace(sock_net(sk), user, len);
1537                 break;
1538
1539         case ARPT_SO_SET_ADD_COUNTERS:
1540                 ret = do_add_counters(sock_net(sk), user, len, 1);
1541                 break;
1542
1543         default:
1544                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1545                 ret = -EINVAL;
1546         }
1547
1548         return ret;
1549 }
1550
1551 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1552                                      compat_uint_t *size,
1553                                      struct xt_counters *counters,
1554                                      unsigned int *i)
1555 {
1556         struct arpt_entry_target *t;
1557         struct compat_arpt_entry __user *ce;
1558         u_int16_t target_offset, next_offset;
1559         compat_uint_t origsize;
1560         int ret;
1561
1562         ret = -EFAULT;
1563         origsize = *size;
1564         ce = (struct compat_arpt_entry __user *)*dstptr;
1565         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1566                 goto out;
1567
1568         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1569                 goto out;
1570
1571         *dstptr += sizeof(struct compat_arpt_entry);
1572         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1573
1574         target_offset = e->target_offset - (origsize - *size);
1575
1576         t = arpt_get_target(e);
1577         ret = xt_compat_target_to_user(t, dstptr, size);
1578         if (ret)
1579                 goto out;
1580         ret = -EFAULT;
1581         next_offset = e->next_offset - (origsize - *size);
1582         if (put_user(target_offset, &ce->target_offset))
1583                 goto out;
1584         if (put_user(next_offset, &ce->next_offset))
1585                 goto out;
1586
1587         (*i)++;
1588         return 0;
1589 out:
1590         return ret;
1591 }
1592
1593 static int compat_copy_entries_to_user(unsigned int total_size,
1594                                        struct xt_table *table,
1595                                        void __user *userptr)
1596 {
1597         struct xt_counters *counters;
1598         const struct xt_table_info *private = table->private;
1599         void __user *pos;
1600         unsigned int size;
1601         int ret = 0;
1602         void *loc_cpu_entry;
1603         unsigned int i = 0;
1604
1605         counters = alloc_counters(table);
1606         if (IS_ERR(counters))
1607                 return PTR_ERR(counters);
1608
1609         /* choose the copy on our node/cpu */
1610         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1611         pos = userptr;
1612         size = total_size;
1613         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1614                                  compat_copy_entry_to_user,
1615                                  &pos, &size, counters, &i);
1616         vfree(counters);
1617         return ret;
1618 }
1619
1620 struct compat_arpt_get_entries {
1621         char name[ARPT_TABLE_MAXNAMELEN];
1622         compat_uint_t size;
1623         struct compat_arpt_entry entrytable[0];
1624 };
1625
1626 static int compat_get_entries(struct net *net,
1627                               struct compat_arpt_get_entries __user *uptr,
1628                               int *len)
1629 {
1630         int ret;
1631         struct compat_arpt_get_entries get;
1632         struct xt_table *t;
1633
1634         if (*len < sizeof(get)) {
1635                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1636                 return -EINVAL;
1637         }
1638         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1639                 return -EFAULT;
1640         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1641                 duprintf("compat_get_entries: %u != %zu\n",
1642                          *len, sizeof(get) + get.size);
1643                 return -EINVAL;
1644         }
1645
1646         xt_compat_lock(NFPROTO_ARP);
1647         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1648         if (t && !IS_ERR(t)) {
1649                 const struct xt_table_info *private = t->private;
1650                 struct xt_table_info info;
1651
1652                 duprintf("t->private->number = %u\n", private->number);
1653                 ret = compat_table_info(private, &info);
1654                 if (!ret && get.size == info.size) {
1655                         ret = compat_copy_entries_to_user(private->size,
1656                                                           t, uptr->entrytable);
1657                 } else if (!ret) {
1658                         duprintf("compat_get_entries: I've got %u not %u!\n",
1659                                  private->size, get.size);
1660                         ret = -EAGAIN;
1661                 }
1662                 xt_compat_flush_offsets(NFPROTO_ARP);
1663                 module_put(t->me);
1664                 xt_table_unlock(t);
1665         } else
1666                 ret = t ? PTR_ERR(t) : -ENOENT;
1667
1668         xt_compat_unlock(NFPROTO_ARP);
1669         return ret;
1670 }
1671
1672 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1673
1674 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1675                                   int *len)
1676 {
1677         int ret;
1678
1679         if (!capable(CAP_NET_ADMIN))
1680                 return -EPERM;
1681
1682         switch (cmd) {
1683         case ARPT_SO_GET_INFO:
1684                 ret = get_info(sock_net(sk), user, len, 1);
1685                 break;
1686         case ARPT_SO_GET_ENTRIES:
1687                 ret = compat_get_entries(sock_net(sk), user, len);
1688                 break;
1689         default:
1690                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1691         }
1692         return ret;
1693 }
1694 #endif
1695
1696 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1697 {
1698         int ret;
1699
1700         if (!capable(CAP_NET_ADMIN))
1701                 return -EPERM;
1702
1703         switch (cmd) {
1704         case ARPT_SO_SET_REPLACE:
1705                 ret = do_replace(sock_net(sk), user, len);
1706                 break;
1707
1708         case ARPT_SO_SET_ADD_COUNTERS:
1709                 ret = do_add_counters(sock_net(sk), user, len, 0);
1710                 break;
1711
1712         default:
1713                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1714                 ret = -EINVAL;
1715         }
1716
1717         return ret;
1718 }
1719
1720 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1721 {
1722         int ret;
1723
1724         if (!capable(CAP_NET_ADMIN))
1725                 return -EPERM;
1726
1727         switch (cmd) {
1728         case ARPT_SO_GET_INFO:
1729                 ret = get_info(sock_net(sk), user, len, 0);
1730                 break;
1731
1732         case ARPT_SO_GET_ENTRIES:
1733                 ret = get_entries(sock_net(sk), user, len);
1734                 break;
1735
1736         case ARPT_SO_GET_REVISION_TARGET: {
1737                 struct xt_get_revision rev;
1738
1739                 if (*len != sizeof(rev)) {
1740                         ret = -EINVAL;
1741                         break;
1742                 }
1743                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1744                         ret = -EFAULT;
1745                         break;
1746                 }
1747
1748                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1749                                                          rev.revision, 1, &ret),
1750                                         "arpt_%s", rev.name);
1751                 break;
1752         }
1753
1754         default:
1755                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1756                 ret = -EINVAL;
1757         }
1758
1759         return ret;
1760 }
1761
1762 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1763                                      const struct arpt_replace *repl)
1764 {
1765         int ret;
1766         struct xt_table_info *newinfo;
1767         struct xt_table_info bootstrap
1768                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1769         void *loc_cpu_entry;
1770         struct xt_table *new_table;
1771
1772         newinfo = xt_alloc_table_info(repl->size);
1773         if (!newinfo) {
1774                 ret = -ENOMEM;
1775                 goto out;
1776         }
1777
1778         /* choose the copy on our node/cpu */
1779         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1780         memcpy(loc_cpu_entry, repl->entries, repl->size);
1781
1782         ret = translate_table(table->name, table->valid_hooks,
1783                               newinfo, loc_cpu_entry, repl->size,
1784                               repl->num_entries,
1785                               repl->hook_entry,
1786                               repl->underflow);
1787
1788         duprintf("arpt_register_table: translate table gives %d\n", ret);
1789         if (ret != 0)
1790                 goto out_free;
1791
1792         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1793         if (IS_ERR(new_table)) {
1794                 ret = PTR_ERR(new_table);
1795                 goto out_free;
1796         }
1797         return new_table;
1798
1799 out_free:
1800         xt_free_table_info(newinfo);
1801 out:
1802         return ERR_PTR(ret);
1803 }
1804
1805 void arpt_unregister_table(struct xt_table *table)
1806 {
1807         struct xt_table_info *private;
1808         void *loc_cpu_entry;
1809         struct module *table_owner = table->me;
1810
1811         private = xt_unregister_table(table);
1812
1813         /* Decrease module usage counts and free resources */
1814         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1815         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1816                            cleanup_entry, NULL);
1817         if (private->number > private->initial_entries)
1818                 module_put(table_owner);
1819         xt_free_table_info(private);
1820 }
1821
1822 /* The built-in targets: standard (NULL) and error. */
1823 static struct xt_target arpt_standard_target __read_mostly = {
1824         .name           = ARPT_STANDARD_TARGET,
1825         .targetsize     = sizeof(int),
1826         .family         = NFPROTO_ARP,
1827 #ifdef CONFIG_COMPAT
1828         .compatsize     = sizeof(compat_int_t),
1829         .compat_from_user = compat_standard_from_user,
1830         .compat_to_user = compat_standard_to_user,
1831 #endif
1832 };
1833
1834 static struct xt_target arpt_error_target __read_mostly = {
1835         .name           = ARPT_ERROR_TARGET,
1836         .target         = arpt_error,
1837         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1838         .family         = NFPROTO_ARP,
1839 };
1840
1841 static struct nf_sockopt_ops arpt_sockopts = {
1842         .pf             = PF_INET,
1843         .set_optmin     = ARPT_BASE_CTL,
1844         .set_optmax     = ARPT_SO_SET_MAX+1,
1845         .set            = do_arpt_set_ctl,
1846 #ifdef CONFIG_COMPAT
1847         .compat_set     = compat_do_arpt_set_ctl,
1848 #endif
1849         .get_optmin     = ARPT_BASE_CTL,
1850         .get_optmax     = ARPT_SO_GET_MAX+1,
1851         .get            = do_arpt_get_ctl,
1852 #ifdef CONFIG_COMPAT
1853         .compat_get     = compat_do_arpt_get_ctl,
1854 #endif
1855         .owner          = THIS_MODULE,
1856 };
1857
1858 static int __net_init arp_tables_net_init(struct net *net)
1859 {
1860         return xt_proto_init(net, NFPROTO_ARP);
1861 }
1862
1863 static void __net_exit arp_tables_net_exit(struct net *net)
1864 {
1865         xt_proto_fini(net, NFPROTO_ARP);
1866 }
1867
1868 static struct pernet_operations arp_tables_net_ops = {
1869         .init = arp_tables_net_init,
1870         .exit = arp_tables_net_exit,
1871 };
1872
1873 static int __init arp_tables_init(void)
1874 {
1875         int ret;
1876
1877         ret = register_pernet_subsys(&arp_tables_net_ops);
1878         if (ret < 0)
1879                 goto err1;
1880
1881         /* Noone else will be downing sem now, so we won't sleep */
1882         ret = xt_register_target(&arpt_standard_target);
1883         if (ret < 0)
1884                 goto err2;
1885         ret = xt_register_target(&arpt_error_target);
1886         if (ret < 0)
1887                 goto err3;
1888
1889         /* Register setsockopt */
1890         ret = nf_register_sockopt(&arpt_sockopts);
1891         if (ret < 0)
1892                 goto err4;
1893
1894         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1895         return 0;
1896
1897 err4:
1898         xt_unregister_target(&arpt_error_target);
1899 err3:
1900         xt_unregister_target(&arpt_standard_target);
1901 err2:
1902         unregister_pernet_subsys(&arp_tables_net_ops);
1903 err1:
1904         return ret;
1905 }
1906
1907 static void __exit arp_tables_fini(void)
1908 {
1909         nf_unregister_sockopt(&arpt_sockopts);
1910         xt_unregister_target(&arpt_error_target);
1911         xt_unregister_target(&arpt_standard_target);
1912         unregister_pernet_subsys(&arp_tables_net_ops);
1913 }
1914
1915 EXPORT_SYMBOL(arpt_register_table);
1916 EXPORT_SYMBOL(arpt_unregister_table);
1917 EXPORT_SYMBOL(arpt_do_table);
1918
1919 module_init(arp_tables_init);
1920 module_exit(arp_tables_fini);