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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                         continue;
 317                 }
 318
 319                 /* Targets which reenter must return
 320                  * abs. verdicts
 321                  */
 322                 tgpar.target   = t->u.kernel.target;
 323                 tgpar.targinfo = t->data;
 324                 verdict = t->u.kernel.target->target(skb, &tgpar);
 325
 326                 /* Target might have changed stuff. */
 327                 arp = arp_hdr(skb);
 328
 329                 if (verdict == ARPT_CONTINUE)
 330                         e = arpt_next_entry(e);
 331                 else
 332                         /* Verdict */
 333                         break;
 334         } while (!hotdrop);
 335         xt_info_rdunlock_bh();
 336
 337         if (hotdrop)
 338                 return NF_DROP;
 339         else
 340                 return verdict;
 341 }
 342
 343 /* All zeroes == unconditional rule. */
 344 static inline int unconditional(const struct arpt_arp *arp)
 345 {
 346         unsigned int i;
 347
 348         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 349                 if (((__u32 *)arp)[i])
 350                         return 0;
 351
 352         return 1;
 353 }
 354
 355 /* Figures out from what hook each rule can be called: returns 0 if
 356  * there are loops.  Puts hook bitmask in comefrom.
 357  */
 358 static int mark_source_chains(struct xt_table_info *newinfo,
 359                               unsigned int valid_hooks, void *entry0)
 360 {
 361         unsigned int hook;
 362
 363         /* No recursion; use packet counter to save back ptrs (reset
 364          * to 0 as we leave), and comefrom to save source hook bitmask.
 365          */
 366         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 367                 unsigned int pos = newinfo->hook_entry[hook];
 368                 struct arpt_entry *e
 369                         = (struct arpt_entry *)(entry0 + pos);
 370
 371                 if (!(valid_hooks & (1 << hook)))
 372                         continue;
 373
 374                 /* Set initial back pointer. */
 375                 e->counters.pcnt = pos;
 376
 377                 for (;;) {
 378                         const struct arpt_standard_target *t
 379                                 = (void *)arpt_get_target(e);
 380                         int visited = e->comefrom & (1 << hook);
 381
 382                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 383                                 printk("arptables: loop hook %u pos %u %08X.\n",
 384                                        hook, pos, e->comefrom);
 385                                 return 0;
 386                         }
 387                         e->comefrom
 388                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 389
 390                         /* Unconditional return/END. */
 391                         if ((e->target_offset == sizeof(struct arpt_entry)
 392                             && (strcmp(t->target.u.user.name,
 393                                        ARPT_STANDARD_TARGET) == 0)
 394                             && t->verdict < 0
 395                             && unconditional(&e->arp)) || visited) {
 396                                 unsigned int oldpos, size;
 397
 398                                 if ((strcmp(t->target.u.user.name,
 399                                             ARPT_STANDARD_TARGET) == 0) &&
 400                                     t->verdict < -NF_MAX_VERDICT - 1) {
 401                                         duprintf("mark_source_chains: bad "
 402                                                 "negative verdict (%i)\n",
 403                                                                 t->verdict);
 404                                         return 0;
 405                                 }
 406
 407                                 /* Return: backtrack through the last
 408                                  * big jump.
 409                                  */
 410                                 do {
 411                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 412                                         oldpos = pos;
 413                                         pos = e->counters.pcnt;
 414                                         e->counters.pcnt = 0;
 415
 416                                         /* We're at the start. */
 417                                         if (pos == oldpos)
 418                                                 goto next;
 419
 420                                         e = (struct arpt_entry *)
 421                                                 (entry0 + pos);
 422                                 } while (oldpos == pos + e->next_offset);
 423
 424                                 /* Move along one */
 425                                 size = e->next_offset;
 426                                 e = (struct arpt_entry *)
 427                                         (entry0 + pos + size);
 428                                 e->counters.pcnt = pos;
 429                                 pos += size;
 430                         } else {
 431                                 int newpos = t->verdict;
 432
 433                                 if (strcmp(t->target.u.user.name,
 434                                            ARPT_STANDARD_TARGET) == 0
 435                                     && newpos >= 0) {
 436                                         if (newpos > newinfo->size -
 437                                                 sizeof(struct arpt_entry)) {
 438                                                 duprintf("mark_source_chains: "
 439                                                         "bad verdict (%i)\n",
 440                                                                 newpos);
 441                                                 return 0;
 442                                         }
 443
 444                                         /* This a jump; chase it. */
 445                                         duprintf("Jump rule %u -> %u\n",
 446                                                  pos, newpos);
 447                                 } else {
 448                                         /* ... this is a fallthru */
 449                                         newpos = pos + e->next_offset;
 450                                 }
 451                                 e = (struct arpt_entry *)
 452                                         (entry0 + newpos);
 453                                 e->counters.pcnt = pos;
 454                                 pos = newpos;
 455                         }
 456                 }
 457                 next:
 458                 duprintf("Finished chain %u\n", hook);
 459         }
 460         return 1;
 461 }
 462
 463 static inline int check_entry(struct arpt_entry *e, const char *name)
 464 {
 465         const struct arpt_entry_target *t;
 466
 467         if (!arp_checkentry(&e->arp)) {
 468                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 469                 return -EINVAL;
 470         }
 471
 472         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 473                 return -EINVAL;
 474
 475         t = arpt_get_target(e);
 476         if (e->target_offset + t->u.target_size > e->next_offset)
 477                 return -EINVAL;
 478
 479         return 0;
 480 }
 481
 482 static inline int check_target(struct arpt_entry *e, const char *name)
 483 {
 484         struct arpt_entry_target *t = arpt_get_target(e);
 485         int ret;
 486         struct xt_tgchk_param par = {
 487                 .table     = name,
 488                 .entryinfo = e,
 489                 .target    = t->u.kernel.target,
 490                 .targinfo  = t->data,
 491                 .hook_mask = e->comefrom,
 492                 .family    = NFPROTO_ARP,
 493         };
 494
 495         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 496         if (ret < 0) {
 497                 duprintf("arp_tables: check failed for `%s'.\n",
 498                          t->u.kernel.target->name);
 499                 return ret;
 500         }
 501         return 0;
 502 }
 503
 504 static inline int
 505 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 506                  unsigned int *i)
 507 {
 508         struct arpt_entry_target *t;
 509         struct xt_target *target;
 510         int ret;
 511
 512         ret = check_entry(e, name);
 513         if (ret)
 514                 return ret;
 515
 516         t = arpt_get_target(e);
 517         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 518                                                         t->u.user.name,
 519                                                         t->u.user.revision),
 520                                          "arpt_%s", t->u.user.name);
 521         if (IS_ERR(target) || !target) {
 522                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 523                 ret = target ? PTR_ERR(target) : -ENOENT;
 524                 goto out;
 525         }
 526         t->u.kernel.target = target;
 527
 528         ret = check_target(e, name);
 529         if (ret)
 530                 goto err;
 531
 532         (*i)++;
 533         return 0;
 534 err:
 535         module_put(t->u.kernel.target->me);
 536 out:
 537         return ret;
 538 }
 539
 540 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 541                                              struct xt_table_info *newinfo,
 542                                              unsigned char *base,
 543                                              unsigned char *limit,
 544                                              const unsigned int *hook_entries,
 545                                              const unsigned int *underflows,
 546                                              unsigned int *i)
 547 {
 548         unsigned int h;
 549
 550         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 551             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 552                 duprintf("Bad offset %p\n", e);
 553                 return -EINVAL;
 554         }
 555
 556         if (e->next_offset
 557             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 558                 duprintf("checking: element %p size %u\n",
 559                          e, e->next_offset);
 560                 return -EINVAL;
 561         }
 562
 563         /* Check hooks & underflows */
 564         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 565                 if ((unsigned char *)e - base == hook_entries[h])
 566                         newinfo->hook_entry[h] = hook_entries[h];
 567                 if ((unsigned char *)e - base == underflows[h])
 568                         newinfo->underflow[h] = underflows[h];
 569         }
 570
 571         /* FIXME: underflows must be unconditional, standard verdicts
 572            < 0 (not ARPT_RETURN). --RR */
 573
 574         /* Clear counters and comefrom */
 575         e->counters = ((struct xt_counters) { 0, 0 });
 576         e->comefrom = 0;
 577
 578         (*i)++;
 579         return 0;
 580 }
 581
 582 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 583 {
 584         struct xt_tgdtor_param par;
 585         struct arpt_entry_target *t;
 586
 587         if (i && (*i)-- == 0)
 588                 return 1;
 589
 590         t = arpt_get_target(e);
 591         par.target   = t->u.kernel.target;
 592         par.targinfo = t->data;
 593         par.family   = NFPROTO_ARP;
 594         if (par.target->destroy != NULL)
 595                 par.target->destroy(&par);
 596         module_put(par.target->me);
 597         return 0;
 598 }
 599
 600 /* Checks and translates the user-supplied table segment (held in
 601  * newinfo).
 602  */
 603 static int translate_table(const char *name,
 604                            unsigned int valid_hooks,
 605                            struct xt_table_info *newinfo,
 606                            void *entry0,
 607                            unsigned int size,
 608                            unsigned int number,
 609                            const unsigned int *hook_entries,
 610                            const unsigned int *underflows)
 611 {
 612         unsigned int i;
 613         int ret;
 614
 615         newinfo->size = size;
 616         newinfo->number = number;
 617
 618         /* Init all hooks to impossible value. */
 619         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 620                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 621                 newinfo->underflow[i] = 0xFFFFFFFF;
 622         }
 623
 624         duprintf("translate_table: size %u\n", newinfo->size);
 625         i = 0;
 626
 627         /* Walk through entries, checking offsets. */
 628         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 629                                  check_entry_size_and_hooks,
 630                                  newinfo,
 631                                  entry0,
 632                                  entry0 + size,
 633                                  hook_entries, underflows, &i);
 634         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 635         if (ret != 0)
 636                 return ret;
 637
 638         if (i != number) {
 639                 duprintf("translate_table: %u not %u entries\n",
 640                          i, number);
 641                 return -EINVAL;
 642         }
 643
 644         /* Check hooks all assigned */
 645         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 646                 /* Only hooks which are valid */
 647                 if (!(valid_hooks & (1 << i)))
 648                         continue;
 649                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 650                         duprintf("Invalid hook entry %u %u\n",
 651                                  i, hook_entries[i]);
 652                         return -EINVAL;
 653                 }
 654                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 655                         duprintf("Invalid underflow %u %u\n",
 656                                  i, underflows[i]);
 657                         return -EINVAL;
 658                 }
 659         }
 660
 661         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 662                 duprintf("Looping hook\n");
 663                 return -ELOOP;
 664         }
 665
 666         /* Finally, each sanity check must pass */
 667         i = 0;
 668         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 669                                  find_check_entry, name, size, &i);
 670
 671         if (ret != 0) {
 672                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 673                                 cleanup_entry, &i);
 674                 return ret;
 675         }
 676
 677         /* And one copy for every other CPU */
 678         for_each_possible_cpu(i) {
 679                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 680                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 681         }
 682
 683         return ret;
 684 }
 685
 686 /* Gets counters. */
 687 static inline int add_entry_to_counter(const struct arpt_entry *e,
 688                                        struct xt_counters total[],
 689                                        unsigned int *i)
 690 {
 691         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 692
 693         (*i)++;
 694         return 0;
 695 }
 696
 697 static inline int set_entry_to_counter(const struct arpt_entry *e,
 698                                        struct xt_counters total[],
 699                                        unsigned int *i)
 700 {
 701         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 702
 703         (*i)++;
 704         return 0;
 705 }
 706
 707 static void get_counters(const struct xt_table_info *t,
 708                          struct xt_counters counters[])
 709 {
 710         unsigned int cpu;
 711         unsigned int i;
 712         unsigned int curcpu;
 713
 714         /* Instead of clearing (by a previous call to memset())
 715          * the counters and using adds, we set the counters
 716          * with data used by 'current' CPU
 717          *
 718          * Bottom half has to be disabled to prevent deadlock
 719          * if new softirq were to run and call ipt_do_table
 720          */
 721         local_bh_disable();
 722         curcpu = smp_processor_id();
 723
 724         i = 0;
 725         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 726                            t->size,
 727                            set_entry_to_counter,
 728                            counters,
 729                            &i);
 730
 731         for_each_possible_cpu(cpu) {
 732                 if (cpu == curcpu)
 733                         continue;
 734                 i = 0;
 735                 xt_info_wrlock(cpu);
 736                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 737                                    t->size,
 738                                    add_entry_to_counter,
 739                                    counters,
 740                                    &i);
 741                 xt_info_wrunlock(cpu);
 742         }
 743         local_bh_enable();
 744 }
 745
 746 static struct xt_counters *alloc_counters(struct xt_table *table)
 747 {
 748         unsigned int countersize;
 749         struct xt_counters *counters;
 750         struct xt_table_info *private = table->private;
 751
 752         /* We need atomic snapshot of counters: rest doesn't change
 753          * (other than comefrom, which userspace doesn't care
 754          * about).
 755          */
 756         countersize = sizeof(struct xt_counters) * private->number;
 757         counters = vmalloc_node(countersize, numa_node_id());
 758
 759         if (counters == NULL)
 760                 return ERR_PTR(-ENOMEM);
 761
 762         get_counters(private, counters);
 763
 764         return counters;
 765 }
 766
 767 static int copy_entries_to_user(unsigned int total_size,
 768                                 struct xt_table *table,
 769                                 void __user *userptr)
 770 {
 771         unsigned int off, num;
 772         struct arpt_entry *e;
 773         struct xt_counters *counters;
 774         struct xt_table_info *private = table->private;
 775         int ret = 0;
 776         void *loc_cpu_entry;
 777
 778         counters = alloc_counters(table);
 779         if (IS_ERR(counters))
 780                 return PTR_ERR(counters);
 781
 782         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 783         /* ... then copy entire thing ... */
 784         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 785                 ret = -EFAULT;
 786                 goto free_counters;
 787         }
 788
 789         /* FIXME: use iterator macros --RR */
 790         /* ... then go back and fix counters and names */
 791         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 792                 struct arpt_entry_target *t;
 793
 794                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 795                 if (copy_to_user(userptr + off
 796                                  + offsetof(struct arpt_entry, counters),
 797                                  &counters[num],
 798                                  sizeof(counters[num])) != 0) {
 799                         ret = -EFAULT;
 800                         goto free_counters;
 801                 }
 802
 803                 t = arpt_get_target(e);
 804                 if (copy_to_user(userptr + off + e->target_offset
 805                                  + offsetof(struct arpt_entry_target,
 806                                             u.user.name),
 807                                  t->u.kernel.target->name,
 808                                  strlen(t->u.kernel.target->name)+1) != 0) {
 809                         ret = -EFAULT;
 810                         goto free_counters;
 811                 }
 812         }
 813
 814  free_counters:
 815         vfree(counters);
 816         return ret;
 817 }
 818
 819 #ifdef CONFIG_COMPAT
 820 static void compat_standard_from_user(void *dst, void *src)
 821 {
 822         int v = *(compat_int_t *)src;
 823
 824         if (v > 0)
 825                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 826         memcpy(dst, &v, sizeof(v));
 827 }
 828
 829 static int compat_standard_to_user(void __user *dst, void *src)
 830 {
 831         compat_int_t cv = *(int *)src;
 832
 833         if (cv > 0)
 834                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 835         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 836 }
 837
 838 static int compat_calc_entry(struct arpt_entry *e,
 839                              const struct xt_table_info *info,
 840                              void *base, struct xt_table_info *newinfo)
 841 {
 842         struct arpt_entry_target *t;
 843         unsigned int entry_offset;
 844         int off, i, ret;
 845
 846         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 847         entry_offset = (void *)e - base;
 848
 849         t = arpt_get_target(e);
 850         off += xt_compat_target_offset(t->u.kernel.target);
 851         newinfo->size -= off;
 852         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 853         if (ret)
 854                 return ret;
 855
 856         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 857                 if (info->hook_entry[i] &&
 858                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 859                         newinfo->hook_entry[i] -= off;
 860                 if (info->underflow[i] &&
 861                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 862                         newinfo->underflow[i] -= off;
 863         }
 864         return 0;
 865 }
 866
 867 static int compat_table_info(const struct xt_table_info *info,
 868                              struct xt_table_info *newinfo)
 869 {
 870         void *loc_cpu_entry;
 871
 872         if (!newinfo || !info)
 873                 return -EINVAL;
 874
 875         /* we dont care about newinfo->entries[] */
 876         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 877         newinfo->initial_entries = 0;
 878         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 879         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 880                                   compat_calc_entry, info, loc_cpu_entry,
 881                                   newinfo);
 882 }
 883 #endif
 884
 885 static int get_info(struct net *net, void __user *user, int *len, int compat)
 886 {
 887         char name[ARPT_TABLE_MAXNAMELEN];
 888         struct xt_table *t;
 889         int ret;
 890
 891         if (*len != sizeof(struct arpt_getinfo)) {
 892                 duprintf("length %u != %Zu\n", *len,
 893                          sizeof(struct arpt_getinfo));
 894                 return -EINVAL;
 895         }
 896
 897         if (copy_from_user(name, user, sizeof(name)) != 0)
 898                 return -EFAULT;
 899
 900         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 901 #ifdef CONFIG_COMPAT
 902         if (compat)
 903                 xt_compat_lock(NFPROTO_ARP);
 904 #endif
 905         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 906                                     "arptable_%s", name);
 907         if (t && !IS_ERR(t)) {
 908                 struct arpt_getinfo info;
 909                 const struct xt_table_info *private = t->private;
 910
 911 #ifdef CONFIG_COMPAT
 912                 if (compat) {
 913                         struct xt_table_info tmp;
 914                         ret = compat_table_info(private, &tmp);
 915                         xt_compat_flush_offsets(NFPROTO_ARP);
 916                         private = &tmp;
 917                 }
 918 #endif
 919                 info.valid_hooks = t->valid_hooks;
 920                 memcpy(info.hook_entry, private->hook_entry,
 921                        sizeof(info.hook_entry));
 922                 memcpy(info.underflow, private->underflow,
 923                        sizeof(info.underflow));
 924                 info.num_entries = private->number;
 925                 info.size = private->size;
 926                 strcpy(info.name, name);
 927
 928                 if (copy_to_user(user, &info, *len) != 0)
 929                         ret = -EFAULT;
 930                 else
 931                         ret = 0;
 932                 xt_table_unlock(t);
 933                 module_put(t->me);
 934         } else
 935                 ret = t ? PTR_ERR(t) : -ENOENT;
 936 #ifdef CONFIG_COMPAT
 937         if (compat)
 938                 xt_compat_unlock(NFPROTO_ARP);
 939 #endif
 940         return ret;
 941 }
 942
 943 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 944                        int *len)
 945 {
 946         int ret;
 947         struct arpt_get_entries get;
 948         struct xt_table *t;
 949
 950         if (*len < sizeof(get)) {
 951                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 952                 return -EINVAL;
 953         }
 954         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 955                 return -EFAULT;
 956         if (*len != sizeof(struct arpt_get_entries) + get.size) {
 957                 duprintf("get_entries: %u != %Zu\n", *len,
 958                          sizeof(struct arpt_get_entries) + get.size);
 959                 return -EINVAL;
 960         }
 961
 962         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 963         if (t && !IS_ERR(t)) {
 964                 const struct xt_table_info *private = t->private;
 965
 966                 duprintf("t->private->number = %u\n",
 967                          private->number);
 968                 if (get.size == private->size)
 969                         ret = copy_entries_to_user(private->size,
 970                                                    t, uptr->entrytable);
 971                 else {
 972                         duprintf("get_entries: I've got %u not %u!\n",
 973                                  private->size, get.size);
 974                         ret = -EAGAIN;
 975                 }
 976                 module_put(t->me);
 977                 xt_table_unlock(t);
 978         } else
 979                 ret = t ? PTR_ERR(t) : -ENOENT;
 980
 981         return ret;
 982 }
 983
 984 static int __do_replace(struct net *net, const char *name,
 985                         unsigned int valid_hooks,
 986                         struct xt_table_info *newinfo,
 987                         unsigned int num_counters,
 988                         void __user *counters_ptr)
 989 {
 990         int ret;
 991         struct xt_table *t;
 992         struct xt_table_info *oldinfo;
 993         struct xt_counters *counters;
 994         void *loc_cpu_old_entry;
 995
 996         ret = 0;
 997         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
 998                                 numa_node_id());
 999         if (!counters) {
1000                 ret = -ENOMEM;
1001                 goto out;
1002         }
1003
1004         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1005                                     "arptable_%s", name);
1006         if (!t || IS_ERR(t)) {
1007                 ret = t ? PTR_ERR(t) : -ENOENT;
1008                 goto free_newinfo_counters_untrans;
1009         }
1010
1011         /* You lied! */
1012         if (valid_hooks != t->valid_hooks) {
1013                 duprintf("Valid hook crap: %08X vs %08X\n",
1014                          valid_hooks, t->valid_hooks);
1015                 ret = -EINVAL;
1016                 goto put_module;
1017         }
1018
1019         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1020         if (!oldinfo)
1021                 goto put_module;
1022
1023         /* Update module usage count based on number of rules */
1024         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1025                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1026         if ((oldinfo->number > oldinfo->initial_entries) ||
1027             (newinfo->number <= oldinfo->initial_entries))
1028                 module_put(t->me);
1029         if ((oldinfo->number > oldinfo->initial_entries) &&
1030             (newinfo->number <= oldinfo->initial_entries))
1031                 module_put(t->me);
1032
1033         /* Get the old counters, and synchronize with replace */
1034         get_counters(oldinfo, counters);
1035
1036         /* Decrease module usage counts and free resource */
1037         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1038         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1039                            NULL);
1040
1041         xt_free_table_info(oldinfo);
1042         if (copy_to_user(counters_ptr, counters,
1043                          sizeof(struct xt_counters) * num_counters) != 0)
1044                 ret = -EFAULT;
1045         vfree(counters);
1046         xt_table_unlock(t);
1047         return ret;
1048
1049  put_module:
1050         module_put(t->me);
1051         xt_table_unlock(t);
1052  free_newinfo_counters_untrans:
1053         vfree(counters);
1054  out:
1055         return ret;
1056 }
1057
1058 static int do_replace(struct net *net, void __user *user, unsigned int len)
1059 {
1060         int ret;
1061         struct arpt_replace tmp;
1062         struct xt_table_info *newinfo;
1063         void *loc_cpu_entry;
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
1072         newinfo = xt_alloc_table_info(tmp.size);
1073         if (!newinfo)
1074                 return -ENOMEM;
1075
1076         /* choose the copy that is on our node/cpu */
1077         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1078         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1079                            tmp.size) != 0) {
1080                 ret = -EFAULT;
1081                 goto free_newinfo;
1082         }
1083
1084         ret = translate_table(tmp.name, tmp.valid_hooks,
1085                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1086                               tmp.hook_entry, tmp.underflow);
1087         if (ret != 0)
1088                 goto free_newinfo;
1089
1090         duprintf("arp_tables: Translated table\n");
1091
1092         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1093                            tmp.num_counters, tmp.counters);
1094         if (ret)
1095                 goto free_newinfo_untrans;
1096         return 0;
1097
1098  free_newinfo_untrans:
1099         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1100  free_newinfo:
1101         xt_free_table_info(newinfo);
1102         return ret;
1103 }
1104
1105 /* We're lazy, and add to the first CPU; overflow works its fey magic
1106  * and everything is OK. */
1107 static int
1108 add_counter_to_entry(struct arpt_entry *e,
1109                      const struct xt_counters addme[],
1110                      unsigned int *i)
1111 {
1112         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
1113
1114         (*i)++;
1115         return 0;
1116 }
1117
1118 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1119                            int compat)
1120 {
1121         unsigned int i, curcpu;
1122         struct xt_counters_info tmp;
1123         struct xt_counters *paddc;
1124         unsigned int num_counters;
1125         const char *name;
1126         int size;
1127         void *ptmp;
1128         struct xt_table *t;
1129         const struct xt_table_info *private;
1130         int ret = 0;
1131         void *loc_cpu_entry;
1132 #ifdef CONFIG_COMPAT
1133         struct compat_xt_counters_info compat_tmp;
1134
1135         if (compat) {
1136                 ptmp = &compat_tmp;
1137                 size = sizeof(struct compat_xt_counters_info);
1138         } else
1139 #endif
1140         {
1141                 ptmp = &tmp;
1142                 size = sizeof(struct xt_counters_info);
1143         }
1144
1145         if (copy_from_user(ptmp, user, size) != 0)
1146                 return -EFAULT;
1147
1148 #ifdef CONFIG_COMPAT
1149         if (compat) {
1150                 num_counters = compat_tmp.num_counters;
1151                 name = compat_tmp.name;
1152         } else
1153 #endif
1154         {
1155                 num_counters = tmp.num_counters;
1156                 name = tmp.name;
1157         }
1158
1159         if (len != size + num_counters * sizeof(struct xt_counters))
1160                 return -EINVAL;
1161
1162         paddc = vmalloc_node(len - size, numa_node_id());
1163         if (!paddc)
1164                 return -ENOMEM;
1165
1166         if (copy_from_user(paddc, user + size, len - size) != 0) {
1167                 ret = -EFAULT;
1168                 goto free;
1169         }
1170
1171         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1172         if (!t || IS_ERR(t)) {
1173                 ret = t ? PTR_ERR(t) : -ENOENT;
1174                 goto free;
1175         }
1176
1177         local_bh_disable();
1178         private = t->private;
1179         if (private->number != num_counters) {
1180                 ret = -EINVAL;
1181                 goto unlock_up_free;
1182         }
1183
1184         i = 0;
1185         /* Choose the copy that is on our node */
1186         curcpu = smp_processor_id();
1187         loc_cpu_entry = private->entries[curcpu];
1188         xt_info_wrlock(curcpu);
1189         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1190                            private->size,
1191                            add_counter_to_entry,
1192                            paddc,
1193                            &i);
1194         xt_info_wrunlock(curcpu);
1195  unlock_up_free:
1196         local_bh_enable();
1197         xt_table_unlock(t);
1198         module_put(t->me);
1199  free:
1200         vfree(paddc);
1201
1202         return ret;
1203 }
1204
1205 #ifdef CONFIG_COMPAT
1206 static inline int
1207 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1208 {
1209         struct arpt_entry_target *t;
1210
1211         if (i && (*i)-- == 0)
1212                 return 1;
1213
1214         t = compat_arpt_get_target(e);
1215         module_put(t->u.kernel.target->me);
1216         return 0;
1217 }
1218
1219 static inline int
1220 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1221                                   struct xt_table_info *newinfo,
1222                                   unsigned int *size,
1223                                   unsigned char *base,
1224                                   unsigned char *limit,
1225                                   unsigned int *hook_entries,
1226                                   unsigned int *underflows,
1227                                   unsigned int *i,
1228                                   const char *name)
1229 {
1230         struct arpt_entry_target *t;
1231         struct xt_target *target;
1232         unsigned int entry_offset;
1233         int ret, off, h;
1234
1235         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1236         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1237             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1238                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1239                 return -EINVAL;
1240         }
1241
1242         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1243                              sizeof(struct compat_xt_entry_target)) {
1244                 duprintf("checking: element %p size %u\n",
1245                          e, e->next_offset);
1246                 return -EINVAL;
1247         }
1248
1249         /* For purposes of check_entry casting the compat entry is fine */
1250         ret = check_entry((struct arpt_entry *)e, name);
1251         if (ret)
1252                 return ret;
1253
1254         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1255         entry_offset = (void *)e - (void *)base;
1256
1257         t = compat_arpt_get_target(e);
1258         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1259                                                         t->u.user.name,
1260                                                         t->u.user.revision),
1261                                          "arpt_%s", t->u.user.name);
1262         if (IS_ERR(target) || !target) {
1263                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1264                          t->u.user.name);
1265                 ret = target ? PTR_ERR(target) : -ENOENT;
1266                 goto out;
1267         }
1268         t->u.kernel.target = target;
1269
1270         off += xt_compat_target_offset(target);
1271         *size += off;
1272         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1273         if (ret)
1274                 goto release_target;
1275
1276         /* Check hooks & underflows */
1277         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1278                 if ((unsigned char *)e - base == hook_entries[h])
1279                         newinfo->hook_entry[h] = hook_entries[h];
1280                 if ((unsigned char *)e - base == underflows[h])
1281                         newinfo->underflow[h] = underflows[h];
1282         }
1283
1284         /* Clear counters and comefrom */
1285         memset(&e->counters, 0, sizeof(e->counters));
1286         e->comefrom = 0;
1287
1288         (*i)++;
1289         return 0;
1290
1291 release_target:
1292         module_put(t->u.kernel.target->me);
1293 out:
1294         return ret;
1295 }
1296
1297 static int
1298 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1299                             unsigned int *size, const char *name,
1300                             struct xt_table_info *newinfo, unsigned char *base)
1301 {
1302         struct arpt_entry_target *t;
1303         struct xt_target *target;
1304         struct arpt_entry *de;
1305         unsigned int origsize;
1306         int ret, h;
1307
1308         ret = 0;
1309         origsize = *size;
1310         de = (struct arpt_entry *)*dstptr;
1311         memcpy(de, e, sizeof(struct arpt_entry));
1312         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1313
1314         *dstptr += sizeof(struct arpt_entry);
1315         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1316
1317         de->target_offset = e->target_offset - (origsize - *size);
1318         t = compat_arpt_get_target(e);
1319         target = t->u.kernel.target;
1320         xt_compat_target_from_user(t, dstptr, size);
1321
1322         de->next_offset = e->next_offset - (origsize - *size);
1323         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1324                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1325                         newinfo->hook_entry[h] -= origsize - *size;
1326                 if ((unsigned char *)de - base < newinfo->underflow[h])
1327                         newinfo->underflow[h] -= origsize - *size;
1328         }
1329         return ret;
1330 }
1331
1332 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1333                                      unsigned int *i)
1334 {
1335         int ret;
1336
1337         ret = check_target(e, name);
1338         if (ret)
1339                 return ret;
1340
1341         (*i)++;
1342         return 0;
1343 }
1344
1345 static int translate_compat_table(const char *name,
1346                                   unsigned int valid_hooks,
1347                                   struct xt_table_info **pinfo,
1348                                   void **pentry0,
1349                                   unsigned int total_size,
1350                                   unsigned int number,
1351                                   unsigned int *hook_entries,
1352                                   unsigned int *underflows)
1353 {
1354         unsigned int i, j;
1355         struct xt_table_info *newinfo, *info;
1356         void *pos, *entry0, *entry1;
1357         unsigned int size;
1358         int ret;
1359
1360         info = *pinfo;
1361         entry0 = *pentry0;
1362         size = total_size;
1363         info->number = number;
1364
1365         /* Init all hooks to impossible value. */
1366         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1367                 info->hook_entry[i] = 0xFFFFFFFF;
1368                 info->underflow[i] = 0xFFFFFFFF;
1369         }
1370
1371         duprintf("translate_compat_table: size %u\n", info->size);
1372         j = 0;
1373         xt_compat_lock(NFPROTO_ARP);
1374         /* Walk through entries, checking offsets. */
1375         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1376                                         check_compat_entry_size_and_hooks,
1377                                         info, &size, entry0,
1378                                         entry0 + total_size,
1379                                         hook_entries, underflows, &j, name);
1380         if (ret != 0)
1381                 goto out_unlock;
1382
1383         ret = -EINVAL;
1384         if (j != number) {
1385                 duprintf("translate_compat_table: %u not %u entries\n",
1386                          j, number);
1387                 goto out_unlock;
1388         }
1389
1390         /* Check hooks all assigned */
1391         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1392                 /* Only hooks which are valid */
1393                 if (!(valid_hooks & (1 << i)))
1394                         continue;
1395                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1396                         duprintf("Invalid hook entry %u %u\n",
1397                                  i, hook_entries[i]);
1398                         goto out_unlock;
1399                 }
1400                 if (info->underflow[i] == 0xFFFFFFFF) {
1401                         duprintf("Invalid underflow %u %u\n",
1402                                  i, underflows[i]);
1403                         goto out_unlock;
1404                 }
1405         }
1406
1407         ret = -ENOMEM;
1408         newinfo = xt_alloc_table_info(size);
1409         if (!newinfo)
1410                 goto out_unlock;
1411
1412         newinfo->number = number;
1413         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1414                 newinfo->hook_entry[i] = info->hook_entry[i];
1415                 newinfo->underflow[i] = info->underflow[i];
1416         }
1417         entry1 = newinfo->entries[raw_smp_processor_id()];
1418         pos = entry1;
1419         size = total_size;
1420         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1421                                         compat_copy_entry_from_user,
1422                                         &pos, &size, name, newinfo, entry1);
1423         xt_compat_flush_offsets(NFPROTO_ARP);
1424         xt_compat_unlock(NFPROTO_ARP);
1425         if (ret)
1426                 goto free_newinfo;
1427
1428         ret = -ELOOP;
1429         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1430                 goto free_newinfo;
1431
1432         i = 0;
1433         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1434                                  name, &i);
1435         if (ret) {
1436                 j -= i;
1437                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1438                                                    compat_release_entry, &j);
1439                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1440                 xt_free_table_info(newinfo);
1441                 return ret;
1442         }
1443
1444         /* And one copy for every other CPU */
1445         for_each_possible_cpu(i)
1446                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1447                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1448
1449         *pinfo = newinfo;
1450         *pentry0 = entry1;
1451         xt_free_table_info(info);
1452         return 0;
1453
1454 free_newinfo:
1455         xt_free_table_info(newinfo);
1456 out:
1457         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1458         return ret;
1459 out_unlock:
1460         xt_compat_flush_offsets(NFPROTO_ARP);
1461         xt_compat_unlock(NFPROTO_ARP);
1462         goto out;
1463 }
1464
1465 struct compat_arpt_replace {
1466         char                            name[ARPT_TABLE_MAXNAMELEN];
1467         u32                             valid_hooks;
1468         u32                             num_entries;
1469         u32                             size;
1470         u32                             hook_entry[NF_ARP_NUMHOOKS];
1471         u32                             underflow[NF_ARP_NUMHOOKS];
1472         u32                             num_counters;
1473         compat_uptr_t                   counters;
1474         struct compat_arpt_entry        entries[0];
1475 };
1476
1477 static int compat_do_replace(struct net *net, void __user *user,
1478                              unsigned int len)
1479 {
1480         int ret;
1481         struct compat_arpt_replace tmp;
1482         struct xt_table_info *newinfo;
1483         void *loc_cpu_entry;
1484
1485         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1486                 return -EFAULT;
1487
1488         /* overflow check */
1489         if (tmp.size >= INT_MAX / num_possible_cpus())
1490                 return -ENOMEM;
1491         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1492                 return -ENOMEM;
1493
1494         newinfo = xt_alloc_table_info(tmp.size);
1495         if (!newinfo)
1496                 return -ENOMEM;
1497
1498         /* choose the copy that is on our node/cpu */
1499         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1500         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1501                 ret = -EFAULT;
1502                 goto free_newinfo;
1503         }
1504
1505         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1506                                      &newinfo, &loc_cpu_entry, tmp.size,
1507                                      tmp.num_entries, tmp.hook_entry,
1508                                      tmp.underflow);
1509         if (ret != 0)
1510                 goto free_newinfo;
1511
1512         duprintf("compat_do_replace: Translated table\n");
1513
1514         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1515                            tmp.num_counters, compat_ptr(tmp.counters));
1516         if (ret)
1517                 goto free_newinfo_untrans;
1518         return 0;
1519
1520  free_newinfo_untrans:
1521         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1522  free_newinfo:
1523         xt_free_table_info(newinfo);
1524         return ret;
1525 }
1526
1527 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1528                                   unsigned int len)
1529 {
1530         int ret;
1531
1532         if (!capable(CAP_NET_ADMIN))
1533                 return -EPERM;
1534
1535         switch (cmd) {
1536         case ARPT_SO_SET_REPLACE:
1537                 ret = compat_do_replace(sock_net(sk), user, len);
1538                 break;
1539
1540         case ARPT_SO_SET_ADD_COUNTERS:
1541                 ret = do_add_counters(sock_net(sk), user, len, 1);
1542                 break;
1543
1544         default:
1545                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1546                 ret = -EINVAL;
1547         }
1548
1549         return ret;
1550 }
1551
1552 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1553                                      compat_uint_t *size,
1554                                      struct xt_counters *counters,
1555                                      unsigned int *i)
1556 {
1557         struct arpt_entry_target *t;
1558         struct compat_arpt_entry __user *ce;
1559         u_int16_t target_offset, next_offset;
1560         compat_uint_t origsize;
1561         int ret;
1562
1563         ret = -EFAULT;
1564         origsize = *size;
1565         ce = (struct compat_arpt_entry __user *)*dstptr;
1566         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1567                 goto out;
1568
1569         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1570                 goto out;
1571
1572         *dstptr += sizeof(struct compat_arpt_entry);
1573         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1574
1575         target_offset = e->target_offset - (origsize - *size);
1576
1577         t = arpt_get_target(e);
1578         ret = xt_compat_target_to_user(t, dstptr, size);
1579         if (ret)
1580                 goto out;
1581         ret = -EFAULT;
1582         next_offset = e->next_offset - (origsize - *size);
1583         if (put_user(target_offset, &ce->target_offset))
1584                 goto out;
1585         if (put_user(next_offset, &ce->next_offset))
1586                 goto out;
1587
1588         (*i)++;
1589         return 0;
1590 out:
1591         return ret;
1592 }
1593
1594 static int compat_copy_entries_to_user(unsigned int total_size,
1595                                        struct xt_table *table,
1596                                        void __user *userptr)
1597 {
1598         struct xt_counters *counters;
1599         const struct xt_table_info *private = table->private;
1600         void __user *pos;
1601         unsigned int size;
1602         int ret = 0;
1603         void *loc_cpu_entry;
1604         unsigned int i = 0;
1605
1606         counters = alloc_counters(table);
1607         if (IS_ERR(counters))
1608                 return PTR_ERR(counters);
1609
1610         /* choose the copy on our node/cpu */
1611         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1612         pos = userptr;
1613         size = total_size;
1614         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1615                                  compat_copy_entry_to_user,
1616                                  &pos, &size, counters, &i);
1617         vfree(counters);
1618         return ret;
1619 }
1620
1621 struct compat_arpt_get_entries {
1622         char name[ARPT_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 (!capable(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 (!capable(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 (!capable(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
1749                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1750                                                          rev.revision, 1, &ret),
1751                                         "arpt_%s", rev.name);
1752                 break;
1753         }
1754
1755         default:
1756                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1757                 ret = -EINVAL;
1758         }
1759
1760         return ret;
1761 }
1762
1763 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1764                                      const struct arpt_replace *repl)
1765 {
1766         int ret;
1767         struct xt_table_info *newinfo;
1768         struct xt_table_info bootstrap
1769                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1770         void *loc_cpu_entry;
1771         struct xt_table *new_table;
1772
1773         newinfo = xt_alloc_table_info(repl->size);
1774         if (!newinfo) {
1775                 ret = -ENOMEM;
1776                 goto out;
1777         }
1778
1779         /* choose the copy on our node/cpu */
1780         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1781         memcpy(loc_cpu_entry, repl->entries, repl->size);
1782
1783         ret = translate_table(table->name, table->valid_hooks,
1784                               newinfo, loc_cpu_entry, repl->size,
1785                               repl->num_entries,
1786                               repl->hook_entry,
1787                               repl->underflow);
1788
1789         duprintf("arpt_register_table: translate table gives %d\n", ret);
1790         if (ret != 0)
1791                 goto out_free;
1792
1793         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1794         if (IS_ERR(new_table)) {
1795                 ret = PTR_ERR(new_table);
1796                 goto out_free;
1797         }
1798         return new_table;
1799
1800 out_free:
1801         xt_free_table_info(newinfo);
1802 out:
1803         return ERR_PTR(ret);
1804 }
1805
1806 void arpt_unregister_table(struct xt_table *table)
1807 {
1808         struct xt_table_info *private;
1809         void *loc_cpu_entry;
1810         struct module *table_owner = table->me;
1811
1812         private = xt_unregister_table(table);
1813
1814         /* Decrease module usage counts and free resources */
1815         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1816         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1817                            cleanup_entry, NULL);
1818         if (private->number > private->initial_entries)
1819                 module_put(table_owner);
1820         xt_free_table_info(private);
1821 }
1822
1823 /* The built-in targets: standard (NULL) and error. */
1824 static struct xt_target arpt_standard_target __read_mostly = {
1825         .name           = ARPT_STANDARD_TARGET,
1826         .targetsize     = sizeof(int),
1827         .family         = NFPROTO_ARP,
1828 #ifdef CONFIG_COMPAT
1829         .compatsize     = sizeof(compat_int_t),
1830         .compat_from_user = compat_standard_from_user,
1831         .compat_to_user = compat_standard_to_user,
1832 #endif
1833 };
1834
1835 static struct xt_target arpt_error_target __read_mostly = {
1836         .name           = ARPT_ERROR_TARGET,
1837         .target         = arpt_error,
1838         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1839         .family         = NFPROTO_ARP,
1840 };
1841
1842 static struct nf_sockopt_ops arpt_sockopts = {
1843         .pf             = PF_INET,
1844         .set_optmin     = ARPT_BASE_CTL,
1845         .set_optmax     = ARPT_SO_SET_MAX+1,
1846         .set            = do_arpt_set_ctl,
1847 #ifdef CONFIG_COMPAT
1848         .compat_set     = compat_do_arpt_set_ctl,
1849 #endif
1850         .get_optmin     = ARPT_BASE_CTL,
1851         .get_optmax     = ARPT_SO_GET_MAX+1,
1852         .get            = do_arpt_get_ctl,
1853 #ifdef CONFIG_COMPAT
1854         .compat_get     = compat_do_arpt_get_ctl,
1855 #endif
1856         .owner          = THIS_MODULE,
1857 };
1858
1859 static int __net_init arp_tables_net_init(struct net *net)
1860 {
1861         return xt_proto_init(net, NFPROTO_ARP);
1862 }
1863
1864 static void __net_exit arp_tables_net_exit(struct net *net)
1865 {
1866         xt_proto_fini(net, NFPROTO_ARP);
1867 }
1868
1869 static struct pernet_operations arp_tables_net_ops = {
1870         .init = arp_tables_net_init,
1871         .exit = arp_tables_net_exit,
1872 };
1873
1874 static int __init arp_tables_init(void)
1875 {
1876         int ret;
1877
1878         ret = register_pernet_subsys(&arp_tables_net_ops);
1879         if (ret < 0)
1880                 goto err1;
1881
1882         /* Noone else will be downing sem now, so we won't sleep */
1883         ret = xt_register_target(&arpt_standard_target);
1884         if (ret < 0)
1885                 goto err2;
1886         ret = xt_register_target(&arpt_error_target);
1887         if (ret < 0)
1888                 goto err3;
1889
1890         /* Register setsockopt */
1891         ret = nf_register_sockopt(&arpt_sockopts);
1892         if (ret < 0)
1893                 goto err4;
1894
1895         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1896         return 0;
1897
1898 err4:
1899         xt_unregister_target(&arpt_error_target);
1900 err3:
1901         xt_unregister_target(&arpt_standard_target);
1902 err2:
1903         unregister_pernet_subsys(&arp_tables_net_ops);
1904 err1:
1905         return ret;
1906 }
1907
1908 static void __exit arp_tables_fini(void)
1909 {
1910         nf_unregister_sockopt(&arpt_sockopts);
1911         xt_unregister_target(&arpt_error_target);
1912         xt_unregister_target(&arpt_standard_target);
1913         unregister_pernet_subsys(&arp_tables_net_ops);
1914 }
1915
1916 EXPORT_SYMBOL(arpt_register_table);
1917 EXPORT_SYMBOL(arpt_unregister_table);
1918 EXPORT_SYMBOL(arpt_do_table);
1919
1920 module_init(arp_tables_init);
1921 module_exit(arp_tables_fini);