net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is stongly inspired on the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17
  18
  19 #include <linux/kmod.h>
  20 #include <linux/module.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/netfilter/x_tables.h>
  23 #include <linux/netfilter_bridge/ebtables.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/mutex.h>
  26 #include <asm/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <net/sock.h>
  30 /* needed for logical [in,out]-dev filtering */
  31 #include "../br_private.h"
  32
  33 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  34                                          "report to author: "format, ## args)
  35 /* #define BUGPRINT(format, args...) */
  36
  37 /*
  38  * Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48    COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_target_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int ebt_do_match (struct ebt_entry_match *m,
  99    const struct sk_buff *skb, struct xt_match_param *par)
 100 {
 101         par->match     = m->u.match;
 102         par->matchinfo = m->data;
 103         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
 104 }
 105
 106 static inline int
 107 ebt_dev_check(const char *entry, const struct net_device *device)
 108 {
 109         int i = 0;
 110         const char *devname;
 111
 112         if (*entry == '\0')
 113                 return 0;
 114         if (!device)
 115                 return 1;
 116         devname = device->name;
 117         /* 1 is the wildcard token */
 118         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 119                 i++;
 120         return (devname[i] != entry[i] && entry[i] != 1);
 121 }
 122
 123 #define FWINV2(bool,invflg) ((bool) ^ !!(e->invflags & invflg))
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct ethhdr *h,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         int verdict, i;
 130
 131         if (e->bitmask & EBT_802_3) {
 132                 if (FWINV2(ntohs(h->h_proto) >= 1536, EBT_IPROTO))
 133                         return 1;
 134         } else if (!(e->bitmask & EBT_NOPROTO) &&
 135            FWINV2(e->ethproto != h->h_proto, EBT_IPROTO))
 136                 return 1;
 137
 138         if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN))
 139                 return 1;
 140         if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
 141                 return 1;
 142         if ((!in || !in->br_port) ? 0 : FWINV2(ebt_dev_check(
 143            e->logical_in, in->br_port->br->dev), EBT_ILOGICALIN))
 144                 return 1;
 145         if ((!out || !out->br_port) ? 0 : FWINV2(ebt_dev_check(
 146            e->logical_out, out->br_port->br->dev), EBT_ILOGICALOUT))
 147                 return 1;
 148
 149         if (e->bitmask & EBT_SOURCEMAC) {
 150                 verdict = 0;
 151                 for (i = 0; i < 6; i++)
 152                         verdict |= (h->h_source[i] ^ e->sourcemac[i]) &
 153                            e->sourcemsk[i];
 154                 if (FWINV2(verdict != 0, EBT_ISOURCE) )
 155                         return 1;
 156         }
 157         if (e->bitmask & EBT_DESTMAC) {
 158                 verdict = 0;
 159                 for (i = 0; i < 6; i++)
 160                         verdict |= (h->h_dest[i] ^ e->destmac[i]) &
 161                            e->destmsk[i];
 162                 if (FWINV2(verdict != 0, EBT_IDEST) )
 163                         return 1;
 164         }
 165         return 0;
 166 }
 167
 168 static inline __pure
 169 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 170 {
 171         return (void *)entry + entry->next_offset;
 172 }
 173
 174 /* Do some firewalling */
 175 unsigned int ebt_do_table (unsigned int hook, struct sk_buff *skb,
 176    const struct net_device *in, const struct net_device *out,
 177    struct ebt_table *table)
 178 {
 179         int i, nentries;
 180         struct ebt_entry *point;
 181         struct ebt_counter *counter_base, *cb_base;
 182         const struct ebt_entry_target *t;
 183         int verdict, sp = 0;
 184         struct ebt_chainstack *cs;
 185         struct ebt_entries *chaininfo;
 186         const char *base;
 187         const struct ebt_table_info *private;
 188         bool hotdrop = false;
 189         struct xt_match_param mtpar;
 190         struct xt_target_param tgpar;
 191
 192         mtpar.family  = tgpar.family = NFPROTO_BRIDGE;
 193         mtpar.in      = tgpar.in  = in;
 194         mtpar.out     = tgpar.out = out;
 195         mtpar.hotdrop = &hotdrop;
 196         mtpar.hooknum = tgpar.hooknum = hook;
 197
 198         read_lock_bh(&table->lock);
 199         private = table->private;
 200         cb_base = COUNTER_BASE(private->counters, private->nentries,
 201            smp_processor_id());
 202         if (private->chainstack)
 203                 cs = private->chainstack[smp_processor_id()];
 204         else
 205                 cs = NULL;
 206         chaininfo = private->hook_entry[hook];
 207         nentries = private->hook_entry[hook]->nentries;
 208         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 209         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 210         /* base for chain jumps */
 211         base = private->entries;
 212         i = 0;
 213         while (i < nentries) {
 214                 if (ebt_basic_match(point, eth_hdr(skb), in, out))
 215                         goto letscontinue;
 216
 217                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &mtpar) != 0)
 218                         goto letscontinue;
 219                 if (hotdrop) {
 220                         read_unlock_bh(&table->lock);
 221                         return NF_DROP;
 222                 }
 223
 224                 /* increase counter */
 225                 (*(counter_base + i)).pcnt++;
 226                 (*(counter_base + i)).bcnt += skb->len;
 227
 228                 /* these should only watch: not modify, nor tell us
 229                    what to do with the packet */
 230                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &tgpar);
 231
 232                 t = (struct ebt_entry_target *)
 233                    (((char *)point) + point->target_offset);
 234                 /* standard target */
 235                 if (!t->u.target->target)
 236                         verdict = ((struct ebt_standard_target *)t)->verdict;
 237                 else {
 238                         tgpar.target   = t->u.target;
 239                         tgpar.targinfo = t->data;
 240                         verdict = t->u.target->target(skb, &tgpar);
 241                 }
 242                 if (verdict == EBT_ACCEPT) {
 243                         read_unlock_bh(&table->lock);
 244                         return NF_ACCEPT;
 245                 }
 246                 if (verdict == EBT_DROP) {
 247                         read_unlock_bh(&table->lock);
 248                         return NF_DROP;
 249                 }
 250                 if (verdict == EBT_RETURN) {
 251 letsreturn:
 252 #ifdef CONFIG_NETFILTER_DEBUG
 253                         if (sp == 0) {
 254                                 BUGPRINT("RETURN on base chain");
 255                                 /* act like this is EBT_CONTINUE */
 256                                 goto letscontinue;
 257                         }
 258 #endif
 259                         sp--;
 260                         /* put all the local variables right */
 261                         i = cs[sp].n;
 262                         chaininfo = cs[sp].chaininfo;
 263                         nentries = chaininfo->nentries;
 264                         point = cs[sp].e;
 265                         counter_base = cb_base +
 266                            chaininfo->counter_offset;
 267                         continue;
 268                 }
 269                 if (verdict == EBT_CONTINUE)
 270                         goto letscontinue;
 271 #ifdef CONFIG_NETFILTER_DEBUG
 272                 if (verdict < 0) {
 273                         BUGPRINT("bogus standard verdict\n");
 274                         read_unlock_bh(&table->lock);
 275                         return NF_DROP;
 276                 }
 277 #endif
 278                 /* jump to a udc */
 279                 cs[sp].n = i + 1;
 280                 cs[sp].chaininfo = chaininfo;
 281                 cs[sp].e = ebt_next_entry(point);
 282                 i = 0;
 283                 chaininfo = (struct ebt_entries *) (base + verdict);
 284 #ifdef CONFIG_NETFILTER_DEBUG
 285                 if (chaininfo->distinguisher) {
 286                         BUGPRINT("jump to non-chain\n");
 287                         read_unlock_bh(&table->lock);
 288                         return NF_DROP;
 289                 }
 290 #endif
 291                 nentries = chaininfo->nentries;
 292                 point = (struct ebt_entry *)chaininfo->data;
 293                 counter_base = cb_base + chaininfo->counter_offset;
 294                 sp++;
 295                 continue;
 296 letscontinue:
 297                 point = ebt_next_entry(point);
 298                 i++;
 299         }
 300
 301         /* I actually like this :) */
 302         if (chaininfo->policy == EBT_RETURN)
 303                 goto letsreturn;
 304         if (chaininfo->policy == EBT_ACCEPT) {
 305                 read_unlock_bh(&table->lock);
 306                 return NF_ACCEPT;
 307         }
 308         read_unlock_bh(&table->lock);
 309         return NF_DROP;
 310 }
 311
 312 /* If it succeeds, returns element and locks mutex */
 313 static inline void *
 314 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 315    struct mutex *mutex)
 316 {
 317         struct {
 318                 struct list_head list;
 319                 char name[EBT_FUNCTION_MAXNAMELEN];
 320         } *e;
 321
 322         *error = mutex_lock_interruptible(mutex);
 323         if (*error != 0)
 324                 return NULL;
 325
 326         list_for_each_entry(e, head, list) {
 327                 if (strcmp(e->name, name) == 0)
 328                         return e;
 329         }
 330         *error = -ENOENT;
 331         mutex_unlock(mutex);
 332         return NULL;
 333 }
 334
 335 static void *
 336 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 337    int *error, struct mutex *mutex)
 338 {
 339         return try_then_request_module(
 340                         find_inlist_lock_noload(head, name, error, mutex),
 341                         "%s%s", prefix, name);
 342 }
 343
 344 static inline struct ebt_table *
 345 find_table_lock(struct net *net, const char *name, int *error,
 346                 struct mutex *mutex)
 347 {
 348         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 349                                 "ebtable_", error, mutex);
 350 }
 351
 352 static inline int
 353 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 354                 unsigned int *cnt)
 355 {
 356         const struct ebt_entry *e = par->entryinfo;
 357         struct xt_match *match;
 358         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 359         int ret;
 360
 361         if (left < sizeof(struct ebt_entry_match) ||
 362             left - sizeof(struct ebt_entry_match) < m->match_size)
 363                 return -EINVAL;
 364
 365         match = try_then_request_module(xt_find_match(NFPROTO_BRIDGE,
 366                 m->u.name, 0), "ebt_%s", m->u.name);
 367         if (IS_ERR(match))
 368                 return PTR_ERR(match);
 369         if (match == NULL)
 370                 return -ENOENT;
 371         m->u.match = match;
 372
 373         par->match     = match;
 374         par->matchinfo = m->data;
 375         ret = xt_check_match(par, m->match_size,
 376               e->ethproto, e->invflags & EBT_IPROTO);
 377         if (ret < 0) {
 378                 module_put(match->me);
 379                 return ret;
 380         }
 381
 382         (*cnt)++;
 383         return 0;
 384 }
 385
 386 static inline int
 387 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 388                   unsigned int *cnt)
 389 {
 390         const struct ebt_entry *e = par->entryinfo;
 391         struct xt_target *watcher;
 392         size_t left = ((char *)e + e->target_offset) - (char *)w;
 393         int ret;
 394
 395         if (left < sizeof(struct ebt_entry_watcher) ||
 396            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 397                 return -EINVAL;
 398
 399         watcher = try_then_request_module(
 400                   xt_find_target(NFPROTO_BRIDGE, w->u.name, 0),
 401                   "ebt_%s", w->u.name);
 402         if (IS_ERR(watcher))
 403                 return PTR_ERR(watcher);
 404         if (watcher == NULL)
 405                 return -ENOENT;
 406         w->u.watcher = watcher;
 407
 408         par->target   = watcher;
 409         par->targinfo = w->data;
 410         ret = xt_check_target(par, w->watcher_size,
 411               e->ethproto, e->invflags & EBT_IPROTO);
 412         if (ret < 0) {
 413                 module_put(watcher->me);
 414                 return ret;
 415         }
 416
 417         (*cnt)++;
 418         return 0;
 419 }
 420
 421 static int ebt_verify_pointers(const struct ebt_replace *repl,
 422                                struct ebt_table_info *newinfo)
 423 {
 424         unsigned int limit = repl->entries_size;
 425         unsigned int valid_hooks = repl->valid_hooks;
 426         unsigned int offset = 0;
 427         int i;
 428
 429         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 430                 newinfo->hook_entry[i] = NULL;
 431
 432         newinfo->entries_size = repl->entries_size;
 433         newinfo->nentries = repl->nentries;
 434
 435         while (offset < limit) {
 436                 size_t left = limit - offset;
 437                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 438
 439                 if (left < sizeof(unsigned int))
 440                         break;
 441
 442                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 443                         if ((valid_hooks & (1 << i)) == 0)
 444                                 continue;
 445                         if ((char __user *)repl->hook_entry[i] ==
 446                              repl->entries + offset)
 447                                 break;
 448                 }
 449
 450                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 451                         if (e->bitmask != 0) {
 452                                 /* we make userspace set this right,
 453                                    so there is no misunderstanding */
 454                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 455                                          "in distinguisher\n");
 456                                 return -EINVAL;
 457                         }
 458                         if (i != NF_BR_NUMHOOKS)
 459                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 460                         if (left < sizeof(struct ebt_entries))
 461                                 break;
 462                         offset += sizeof(struct ebt_entries);
 463                 } else {
 464                         if (left < sizeof(struct ebt_entry))
 465                                 break;
 466                         if (left < e->next_offset)
 467                                 break;
 468                         if (e->next_offset < sizeof(struct ebt_entry))
 469                                 return -EINVAL;
 470                         offset += e->next_offset;
 471                 }
 472         }
 473         if (offset != limit) {
 474                 BUGPRINT("entries_size too small\n");
 475                 return -EINVAL;
 476         }
 477
 478         /* check if all valid hooks have a chain */
 479         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 480                 if (!newinfo->hook_entry[i] &&
 481                    (valid_hooks & (1 << i))) {
 482                         BUGPRINT("Valid hook without chain\n");
 483                         return -EINVAL;
 484                 }
 485         }
 486         return 0;
 487 }
 488
 489 /*
 490  * this one is very careful, as it is the first function
 491  * to parse the userspace data
 492  */
 493 static inline int
 494 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 495    const struct ebt_table_info *newinfo,
 496    unsigned int *n, unsigned int *cnt,
 497    unsigned int *totalcnt, unsigned int *udc_cnt)
 498 {
 499         int i;
 500
 501         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 502                 if ((void *)e == (void *)newinfo->hook_entry[i])
 503                         break;
 504         }
 505         /* beginning of a new chain
 506            if i == NF_BR_NUMHOOKS it must be a user defined chain */
 507         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 508                 /* this checks if the previous chain has as many entries
 509                    as it said it has */
 510                 if (*n != *cnt) {
 511                         BUGPRINT("nentries does not equal the nr of entries "
 512                                  "in the chain\n");
 513                         return -EINVAL;
 514                 }
 515                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 516                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 517                         /* only RETURN from udc */
 518                         if (i != NF_BR_NUMHOOKS ||
 519                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 520                                 BUGPRINT("bad policy\n");
 521                                 return -EINVAL;
 522                         }
 523                 }
 524                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 525                         (*udc_cnt)++;
 526                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 527                         BUGPRINT("counter_offset != totalcnt");
 528                         return -EINVAL;
 529                 }
 530                 *n = ((struct ebt_entries *)e)->nentries;
 531                 *cnt = 0;
 532                 return 0;
 533         }
 534         /* a plain old entry, heh */
 535         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 536            e->watchers_offset > e->target_offset ||
 537            e->target_offset >= e->next_offset) {
 538                 BUGPRINT("entry offsets not in right order\n");
 539                 return -EINVAL;
 540         }
 541         /* this is not checked anywhere else */
 542         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 543                 BUGPRINT("target size too small\n");
 544                 return -EINVAL;
 545         }
 546         (*cnt)++;
 547         (*totalcnt)++;
 548         return 0;
 549 }
 550
 551 struct ebt_cl_stack
 552 {
 553         struct ebt_chainstack cs;
 554         int from;
 555         unsigned int hookmask;
 556 };
 557
 558 /*
 559  * we need these positions to check that the jumps to a different part of the
 560  * entries is a jump to the beginning of a new chain.
 561  */
 562 static inline int
 563 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 564    unsigned int *n, struct ebt_cl_stack *udc)
 565 {
 566         int i;
 567
 568         /* we're only interested in chain starts */
 569         if (e->bitmask)
 570                 return 0;
 571         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 572                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 573                         break;
 574         }
 575         /* only care about udc */
 576         if (i != NF_BR_NUMHOOKS)
 577                 return 0;
 578
 579         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 580         /* these initialisations are depended on later in check_chainloops() */
 581         udc[*n].cs.n = 0;
 582         udc[*n].hookmask = 0;
 583
 584         (*n)++;
 585         return 0;
 586 }
 587
 588 static inline int
 589 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 590 {
 591         struct xt_mtdtor_param par;
 592
 593         if (i && (*i)-- == 0)
 594                 return 1;
 595
 596         par.net       = net;
 597         par.match     = m->u.match;
 598         par.matchinfo = m->data;
 599         par.family    = NFPROTO_BRIDGE;
 600         if (par.match->destroy != NULL)
 601                 par.match->destroy(&par);
 602         module_put(par.match->me);
 603         return 0;
 604 }
 605
 606 static inline int
 607 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 608 {
 609         struct xt_tgdtor_param par;
 610
 611         if (i && (*i)-- == 0)
 612                 return 1;
 613
 614         par.net      = net;
 615         par.target   = w->u.watcher;
 616         par.targinfo = w->data;
 617         par.family   = NFPROTO_BRIDGE;
 618         if (par.target->destroy != NULL)
 619                 par.target->destroy(&par);
 620         module_put(par.target->me);
 621         return 0;
 622 }
 623
 624 static inline int
 625 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 626 {
 627         struct xt_tgdtor_param par;
 628         struct ebt_entry_target *t;
 629
 630         if (e->bitmask == 0)
 631                 return 0;
 632         /* we're done */
 633         if (cnt && (*cnt)-- == 0)
 634                 return 1;
 635         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 636         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 637         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 638
 639         par.net      = net;
 640         par.target   = t->u.target;
 641         par.targinfo = t->data;
 642         par.family   = NFPROTO_BRIDGE;
 643         if (par.target->destroy != NULL)
 644                 par.target->destroy(&par);
 645         module_put(par.target->me);
 646         return 0;
 647 }
 648
 649 static inline int
 650 ebt_check_entry(struct ebt_entry *e, struct net *net,
 651    const struct ebt_table_info *newinfo,
 652    const char *name, unsigned int *cnt,
 653    struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 654 {
 655         struct ebt_entry_target *t;
 656         struct xt_target *target;
 657         unsigned int i, j, hook = 0, hookmask = 0;
 658         size_t gap;
 659         int ret;
 660         struct xt_mtchk_param mtpar;
 661         struct xt_tgchk_param tgpar;
 662
 663         /* don't mess with the struct ebt_entries */
 664         if (e->bitmask == 0)
 665                 return 0;
 666
 667         if (e->bitmask & ~EBT_F_MASK) {
 668                 BUGPRINT("Unknown flag for bitmask\n");
 669                 return -EINVAL;
 670         }
 671         if (e->invflags & ~EBT_INV_MASK) {
 672                 BUGPRINT("Unknown flag for inv bitmask\n");
 673                 return -EINVAL;
 674         }
 675         if ( (e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3) ) {
 676                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 677                 return -EINVAL;
 678         }
 679         /* what hook do we belong to? */
 680         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 681                 if (!newinfo->hook_entry[i])
 682                         continue;
 683                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 684                         hook = i;
 685                 else
 686                         break;
 687         }
 688         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 689            a base chain */
 690         if (i < NF_BR_NUMHOOKS)
 691                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 692         else {
 693                 for (i = 0; i < udc_cnt; i++)
 694                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 695                                 break;
 696                 if (i == 0)
 697                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 698                 else
 699                         hookmask = cl_s[i - 1].hookmask;
 700         }
 701         i = 0;
 702
 703         mtpar.net       = tgpar.net       = net;
 704         mtpar.table     = tgpar.table     = name;
 705         mtpar.entryinfo = tgpar.entryinfo = e;
 706         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 707         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 708         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 709         if (ret != 0)
 710                 goto cleanup_matches;
 711         j = 0;
 712         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 713         if (ret != 0)
 714                 goto cleanup_watchers;
 715         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 716         gap = e->next_offset - e->target_offset;
 717
 718         target = try_then_request_module(
 719                  xt_find_target(NFPROTO_BRIDGE, t->u.name, 0),
 720                  "ebt_%s", t->u.name);
 721         if (IS_ERR(target)) {
 722                 ret = PTR_ERR(target);
 723                 goto cleanup_watchers;
 724         } else if (target == NULL) {
 725                 ret = -ENOENT;
 726                 goto cleanup_watchers;
 727         }
 728
 729         t->u.target = target;
 730         if (t->u.target == &ebt_standard_target) {
 731                 if (gap < sizeof(struct ebt_standard_target)) {
 732                         BUGPRINT("Standard target size too big\n");
 733                         ret = -EFAULT;
 734                         goto cleanup_watchers;
 735                 }
 736                 if (((struct ebt_standard_target *)t)->verdict <
 737                    -NUM_STANDARD_TARGETS) {
 738                         BUGPRINT("Invalid standard target\n");
 739                         ret = -EFAULT;
 740                         goto cleanup_watchers;
 741                 }
 742         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 743                 module_put(t->u.target->me);
 744                 ret = -EFAULT;
 745                 goto cleanup_watchers;
 746         }
 747
 748         tgpar.target   = target;
 749         tgpar.targinfo = t->data;
 750         ret = xt_check_target(&tgpar, t->target_size,
 751               e->ethproto, e->invflags & EBT_IPROTO);
 752         if (ret < 0) {
 753                 module_put(target->me);
 754                 goto cleanup_watchers;
 755         }
 756         (*cnt)++;
 757         return 0;
 758 cleanup_watchers:
 759         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 760 cleanup_matches:
 761         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 762         return ret;
 763 }
 764
 765 /*
 766  * checks for loops and sets the hook mask for udc
 767  * the hook mask for udc tells us from which base chains the udc can be
 768  * accessed. This mask is a parameter to the check() functions of the extensions
 769  */
 770 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 771    unsigned int udc_cnt, unsigned int hooknr, char *base)
 772 {
 773         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 774         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 775         const struct ebt_entry_target *t;
 776
 777         while (pos < nentries || chain_nr != -1) {
 778                 /* end of udc, go back one 'recursion' step */
 779                 if (pos == nentries) {
 780                         /* put back values of the time when this chain was called */
 781                         e = cl_s[chain_nr].cs.e;
 782                         if (cl_s[chain_nr].from != -1)
 783                                 nentries =
 784                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 785                         else
 786                                 nentries = chain->nentries;
 787                         pos = cl_s[chain_nr].cs.n;
 788                         /* make sure we won't see a loop that isn't one */
 789                         cl_s[chain_nr].cs.n = 0;
 790                         chain_nr = cl_s[chain_nr].from;
 791                         if (pos == nentries)
 792                                 continue;
 793                 }
 794                 t = (struct ebt_entry_target *)
 795                    (((char *)e) + e->target_offset);
 796                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 797                         goto letscontinue;
 798                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 799                    e->next_offset) {
 800                         BUGPRINT("Standard target size too big\n");
 801                         return -1;
 802                 }
 803                 verdict = ((struct ebt_standard_target *)t)->verdict;
 804                 if (verdict >= 0) { /* jump to another chain */
 805                         struct ebt_entries *hlp2 =
 806                            (struct ebt_entries *)(base + verdict);
 807                         for (i = 0; i < udc_cnt; i++)
 808                                 if (hlp2 == cl_s[i].cs.chaininfo)
 809                                         break;
 810                         /* bad destination or loop */
 811                         if (i == udc_cnt) {
 812                                 BUGPRINT("bad destination\n");
 813                                 return -1;
 814                         }
 815                         if (cl_s[i].cs.n) {
 816                                 BUGPRINT("loop\n");
 817                                 return -1;
 818                         }
 819                         if (cl_s[i].hookmask & (1 << hooknr))
 820                                 goto letscontinue;
 821                         /* this can't be 0, so the loop test is correct */
 822                         cl_s[i].cs.n = pos + 1;
 823                         pos = 0;
 824                         cl_s[i].cs.e = ebt_next_entry(e);
 825                         e = (struct ebt_entry *)(hlp2->data);
 826                         nentries = hlp2->nentries;
 827                         cl_s[i].from = chain_nr;
 828                         chain_nr = i;
 829                         /* this udc is accessible from the base chain for hooknr */
 830                         cl_s[i].hookmask |= (1 << hooknr);
 831                         continue;
 832                 }
 833 letscontinue:
 834                 e = ebt_next_entry(e);
 835                 pos++;
 836         }
 837         return 0;
 838 }
 839
 840 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 841 static int translate_table(struct net *net, const char *name,
 842                            struct ebt_table_info *newinfo)
 843 {
 844         unsigned int i, j, k, udc_cnt;
 845         int ret;
 846         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 847
 848         i = 0;
 849         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 850                 i++;
 851         if (i == NF_BR_NUMHOOKS) {
 852                 BUGPRINT("No valid hooks specified\n");
 853                 return -EINVAL;
 854         }
 855         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 856                 BUGPRINT("Chains don't start at beginning\n");
 857                 return -EINVAL;
 858         }
 859         /* make sure chains are ordered after each other in same order
 860            as their corresponding hooks */
 861         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 862                 if (!newinfo->hook_entry[j])
 863                         continue;
 864                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 865                         BUGPRINT("Hook order must be followed\n");
 866                         return -EINVAL;
 867                 }
 868                 i = j;
 869         }
 870
 871         /* do some early checkings and initialize some things */
 872         i = 0; /* holds the expected nr. of entries for the chain */
 873         j = 0; /* holds the up to now counted entries for the chain */
 874         k = 0; /* holds the total nr. of entries, should equal
 875                   newinfo->nentries afterwards */
 876         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 877         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 878            ebt_check_entry_size_and_hooks, newinfo,
 879            &i, &j, &k, &udc_cnt);
 880
 881         if (ret != 0)
 882                 return ret;
 883
 884         if (i != j) {
 885                 BUGPRINT("nentries does not equal the nr of entries in the "
 886                          "(last) chain\n");
 887                 return -EINVAL;
 888         }
 889         if (k != newinfo->nentries) {
 890                 BUGPRINT("Total nentries is wrong\n");
 891                 return -EINVAL;
 892         }
 893
 894         /* get the location of the udc, put them in an array
 895            while we're at it, allocate the chainstack */
 896         if (udc_cnt) {
 897                 /* this will get free'd in do_replace()/ebt_register_table()
 898                    if an error occurs */
 899                 newinfo->chainstack =
 900                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 901                 if (!newinfo->chainstack)
 902                         return -ENOMEM;
 903                 for_each_possible_cpu(i) {
 904                         newinfo->chainstack[i] =
 905                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 906                         if (!newinfo->chainstack[i]) {
 907                                 while (i)
 908                                         vfree(newinfo->chainstack[--i]);
 909                                 vfree(newinfo->chainstack);
 910                                 newinfo->chainstack = NULL;
 911                                 return -ENOMEM;
 912                         }
 913                 }
 914
 915                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 916                 if (!cl_s)
 917                         return -ENOMEM;
 918                 i = 0; /* the i'th udc */
 919                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 920                    ebt_get_udc_positions, newinfo, &i, cl_s);
 921                 /* sanity check */
 922                 if (i != udc_cnt) {
 923                         BUGPRINT("i != udc_cnt\n");
 924                         vfree(cl_s);
 925                         return -EFAULT;
 926                 }
 927         }
 928
 929         /* Check for loops */
 930         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 931                 if (newinfo->hook_entry[i])
 932                         if (check_chainloops(newinfo->hook_entry[i],
 933                            cl_s, udc_cnt, i, newinfo->entries)) {
 934                                 vfree(cl_s);
 935                                 return -EINVAL;
 936                         }
 937
 938         /* we now know the following (along with E=mc²):
 939            - the nr of entries in each chain is right
 940            - the size of the allocated space is right
 941            - all valid hooks have a corresponding chain
 942            - there are no loops
 943            - wrong data can still be on the level of a single entry
 944            - could be there are jumps to places that are not the
 945              beginning of a chain. This can only occur in chains that
 946              are not accessible from any base chains, so we don't care. */
 947
 948         /* used to know what we need to clean up if something goes wrong */
 949         i = 0;
 950         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 951            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 952         if (ret != 0) {
 953                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 954                                   ebt_cleanup_entry, net, &i);
 955         }
 956         vfree(cl_s);
 957         return ret;
 958 }
 959
 960 /* called under write_lock */
 961 static void get_counters(const struct ebt_counter *oldcounters,
 962    struct ebt_counter *counters, unsigned int nentries)
 963 {
 964         int i, cpu;
 965         struct ebt_counter *counter_base;
 966
 967         /* counters of cpu 0 */
 968         memcpy(counters, oldcounters,
 969                sizeof(struct ebt_counter) * nentries);
 970
 971         /* add other counters to those of cpu 0 */
 972         for_each_possible_cpu(cpu) {
 973                 if (cpu == 0)
 974                         continue;
 975                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 976                 for (i = 0; i < nentries; i++) {
 977                         counters[i].pcnt += counter_base[i].pcnt;
 978                         counters[i].bcnt += counter_base[i].bcnt;
 979                 }
 980         }
 981 }
 982
 983 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 984                               struct ebt_table_info *newinfo)
 985 {
 986         int ret, i;
 987         struct ebt_counter *counterstmp = NULL;
 988         /* used to be able to unlock earlier */
 989         struct ebt_table_info *table;
 990         struct ebt_table *t;
 991
 992         /* the user wants counters back
 993            the check on the size is done later, when we have the lock */
 994         if (repl->num_counters) {
 995                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 996                 counterstmp = vmalloc(size);
 997                 if (!counterstmp)
 998                         return -ENOMEM;
 999         }
1000
1001         newinfo->chainstack = NULL;
1002         ret = ebt_verify_pointers(repl, newinfo);
1003         if (ret != 0)
1004                 goto free_counterstmp;
1005
1006         ret = translate_table(net, repl->name, newinfo);
1007
1008         if (ret != 0)
1009                 goto free_counterstmp;
1010
1011         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1012         if (!t) {
1013                 ret = -ENOENT;
1014                 goto free_iterate;
1015         }
1016
1017         /* the table doesn't like it */
1018         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1019                 goto free_unlock;
1020
1021         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1022                 BUGPRINT("Wrong nr. of counters requested\n");
1023                 ret = -EINVAL;
1024                 goto free_unlock;
1025         }
1026
1027         /* we have the mutex lock, so no danger in reading this pointer */
1028         table = t->private;
1029         /* make sure the table can only be rmmod'ed if it contains no rules */
1030         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1031                 ret = -ENOENT;
1032                 goto free_unlock;
1033         } else if (table->nentries && !newinfo->nentries)
1034                 module_put(t->me);
1035         /* we need an atomic snapshot of the counters */
1036         write_lock_bh(&t->lock);
1037         if (repl->num_counters)
1038                 get_counters(t->private->counters, counterstmp,
1039                    t->private->nentries);
1040
1041         t->private = newinfo;
1042         write_unlock_bh(&t->lock);
1043         mutex_unlock(&ebt_mutex);
1044         /* so, a user can change the chains while having messed up her counter
1045            allocation. Only reason why this is done is because this way the lock
1046            is held only once, while this doesn't bring the kernel into a
1047            dangerous state. */
1048         if (repl->num_counters &&
1049            copy_to_user(repl->counters, counterstmp,
1050            repl->num_counters * sizeof(struct ebt_counter))) {
1051                 ret = -EFAULT;
1052         }
1053         else
1054                 ret = 0;
1055
1056         /* decrease module count and free resources */
1057         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1058                           ebt_cleanup_entry, net, NULL);
1059
1060         vfree(table->entries);
1061         if (table->chainstack) {
1062                 for_each_possible_cpu(i)
1063                         vfree(table->chainstack[i]);
1064                 vfree(table->chainstack);
1065         }
1066         vfree(table);
1067
1068         vfree(counterstmp);
1069         return ret;
1070
1071 free_unlock:
1072         mutex_unlock(&ebt_mutex);
1073 free_iterate:
1074         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1075                           ebt_cleanup_entry, net, NULL);
1076 free_counterstmp:
1077         vfree(counterstmp);
1078         /* can be initialized in translate_table() */
1079         if (newinfo->chainstack) {
1080                 for_each_possible_cpu(i)
1081                         vfree(newinfo->chainstack[i]);
1082                 vfree(newinfo->chainstack);
1083         }
1084         return ret;
1085 }
1086
1087 /* replace the table */
1088 static int do_replace(struct net *net, const void __user *user,
1089                       unsigned int len)
1090 {
1091         int ret, countersize;
1092         struct ebt_table_info *newinfo;
1093         struct ebt_replace tmp;
1094
1095         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1096                 return -EFAULT;
1097
1098         if (len != sizeof(tmp) + tmp.entries_size) {
1099                 BUGPRINT("Wrong len argument\n");
1100                 return -EINVAL;
1101         }
1102
1103         if (tmp.entries_size == 0) {
1104                 BUGPRINT("Entries_size never zero\n");
1105                 return -EINVAL;
1106         }
1107         /* overflow check */
1108         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1109                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1110                 return -ENOMEM;
1111         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1112                 return -ENOMEM;
1113
1114         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1115         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1116         if (!newinfo)
1117                 return -ENOMEM;
1118
1119         if (countersize)
1120                 memset(newinfo->counters, 0, countersize);
1121
1122         newinfo->entries = vmalloc(tmp.entries_size);
1123         if (!newinfo->entries) {
1124                 ret = -ENOMEM;
1125                 goto free_newinfo;
1126         }
1127         if (copy_from_user(
1128            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1129                 BUGPRINT("Couldn't copy entries from userspace\n");
1130                 ret = -EFAULT;
1131                 goto free_entries;
1132         }
1133
1134         ret = do_replace_finish(net, &tmp, newinfo);
1135         if (ret == 0)
1136                 return ret;
1137 free_entries:
1138         vfree(newinfo->entries);
1139 free_newinfo:
1140         vfree(newinfo);
1141         return ret;
1142 }
1143
1144 struct ebt_table *
1145 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1146 {
1147         struct ebt_table_info *newinfo;
1148         struct ebt_table *t, *table;
1149         struct ebt_replace_kernel *repl;
1150         int ret, i, countersize;
1151         void *p;
1152
1153         if (input_table == NULL || (repl = input_table->table) == NULL ||
1154             repl->entries == 0 || repl->entries_size == 0 ||
1155             repl->counters != NULL || input_table->private != NULL) {
1156                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1157                 return ERR_PTR(-EINVAL);
1158         }
1159
1160         /* Don't add one table to multiple lists. */
1161         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1162         if (!table) {
1163                 ret = -ENOMEM;
1164                 goto out;
1165         }
1166
1167         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1168         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1169         ret = -ENOMEM;
1170         if (!newinfo)
1171                 goto free_table;
1172
1173         p = vmalloc(repl->entries_size);
1174         if (!p)
1175                 goto free_newinfo;
1176
1177         memcpy(p, repl->entries, repl->entries_size);
1178         newinfo->entries = p;
1179
1180         newinfo->entries_size = repl->entries_size;
1181         newinfo->nentries = repl->nentries;
1182
1183         if (countersize)
1184                 memset(newinfo->counters, 0, countersize);
1185
1186         /* fill in newinfo and parse the entries */
1187         newinfo->chainstack = NULL;
1188         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1189                 if ((repl->valid_hooks & (1 << i)) == 0)
1190                         newinfo->hook_entry[i] = NULL;
1191                 else
1192                         newinfo->hook_entry[i] = p +
1193                                 ((char *)repl->hook_entry[i] - repl->entries);
1194         }
1195         ret = translate_table(net, repl->name, newinfo);
1196         if (ret != 0) {
1197                 BUGPRINT("Translate_table failed\n");
1198                 goto free_chainstack;
1199         }
1200
1201         if (table->check && table->check(newinfo, table->valid_hooks)) {
1202                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1203                 return ERR_PTR(-EINVAL);
1204         }
1205
1206         table->private = newinfo;
1207         rwlock_init(&table->lock);
1208         ret = mutex_lock_interruptible(&ebt_mutex);
1209         if (ret != 0)
1210                 goto free_chainstack;
1211
1212         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1213                 if (strcmp(t->name, table->name) == 0) {
1214                         ret = -EEXIST;
1215                         BUGPRINT("Table name already exists\n");
1216                         goto free_unlock;
1217                 }
1218         }
1219
1220         /* Hold a reference count if the chains aren't empty */
1221         if (newinfo->nentries && !try_module_get(table->me)) {
1222                 ret = -ENOENT;
1223                 goto free_unlock;
1224         }
1225         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1226         mutex_unlock(&ebt_mutex);
1227         return table;
1228 free_unlock:
1229         mutex_unlock(&ebt_mutex);
1230 free_chainstack:
1231         if (newinfo->chainstack) {
1232                 for_each_possible_cpu(i)
1233                         vfree(newinfo->chainstack[i]);
1234                 vfree(newinfo->chainstack);
1235         }
1236         vfree(newinfo->entries);
1237 free_newinfo:
1238         vfree(newinfo);
1239 free_table:
1240         kfree(table);
1241 out:
1242         return ERR_PTR(ret);
1243 }
1244
1245 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1246 {
1247         int i;
1248
1249         if (!table) {
1250                 BUGPRINT("Request to unregister NULL table!!!\n");
1251                 return;
1252         }
1253         mutex_lock(&ebt_mutex);
1254         list_del(&table->list);
1255         mutex_unlock(&ebt_mutex);
1256         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1257                           ebt_cleanup_entry, net, NULL);
1258         if (table->private->nentries)
1259                 module_put(table->me);
1260         vfree(table->private->entries);
1261         if (table->private->chainstack) {
1262                 for_each_possible_cpu(i)
1263                         vfree(table->private->chainstack[i]);
1264                 vfree(table->private->chainstack);
1265         }
1266         vfree(table->private);
1267         kfree(table);
1268 }
1269
1270 /* userspace just supplied us with counters */
1271 static int do_update_counters(struct net *net, const char *name,
1272                                 struct ebt_counter __user *counters,
1273                                 unsigned int num_counters,
1274                                 const void __user *user, unsigned int len)
1275 {
1276         int i, ret;
1277         struct ebt_counter *tmp;
1278         struct ebt_table *t;
1279
1280         if (num_counters == 0)
1281                 return -EINVAL;
1282
1283         tmp = vmalloc(num_counters * sizeof(*tmp));
1284         if (!tmp)
1285                 return -ENOMEM;
1286
1287         t = find_table_lock(net, name, &ret, &ebt_mutex);
1288         if (!t)
1289                 goto free_tmp;
1290
1291         if (num_counters != t->private->nentries) {
1292                 BUGPRINT("Wrong nr of counters\n");
1293                 ret = -EINVAL;
1294                 goto unlock_mutex;
1295         }
1296
1297         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1298                 ret = -EFAULT;
1299                 goto unlock_mutex;
1300         }
1301
1302         /* we want an atomic add of the counters */
1303         write_lock_bh(&t->lock);
1304
1305         /* we add to the counters of the first cpu */
1306         for (i = 0; i < num_counters; i++) {
1307                 t->private->counters[i].pcnt += tmp[i].pcnt;
1308                 t->private->counters[i].bcnt += tmp[i].bcnt;
1309         }
1310
1311         write_unlock_bh(&t->lock);
1312         ret = 0;
1313 unlock_mutex:
1314         mutex_unlock(&ebt_mutex);
1315 free_tmp:
1316         vfree(tmp);
1317         return ret;
1318 }
1319
1320 static int update_counters(struct net *net, const void __user *user,
1321                             unsigned int len)
1322 {
1323         struct ebt_replace hlp;
1324
1325         if (copy_from_user(&hlp, user, sizeof(hlp)))
1326                 return -EFAULT;
1327
1328         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1329                 return -EINVAL;
1330
1331         return do_update_counters(net, hlp.name, hlp.counters,
1332                                 hlp.num_counters, user, len);
1333 }
1334
1335 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1336     const char *base, char __user *ubase)
1337 {
1338         char __user *hlp = ubase + ((char *)m - base);
1339         if (copy_to_user(hlp, m->u.match->name, EBT_FUNCTION_MAXNAMELEN))
1340                 return -EFAULT;
1341         return 0;
1342 }
1343
1344 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1345     const char *base, char __user *ubase)
1346 {
1347         char __user *hlp = ubase + ((char *)w - base);
1348         if (copy_to_user(hlp , w->u.watcher->name, EBT_FUNCTION_MAXNAMELEN))
1349                 return -EFAULT;
1350         return 0;
1351 }
1352
1353 static inline int
1354 ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase)
1355 {
1356         int ret;
1357         char __user *hlp;
1358         const struct ebt_entry_target *t;
1359
1360         if (e->bitmask == 0)
1361                 return 0;
1362
1363         hlp = ubase + (((char *)e + e->target_offset) - base);
1364         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1365
1366         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1367         if (ret != 0)
1368                 return ret;
1369         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1370         if (ret != 0)
1371                 return ret;
1372         if (copy_to_user(hlp, t->u.target->name, EBT_FUNCTION_MAXNAMELEN))
1373                 return -EFAULT;
1374         return 0;
1375 }
1376
1377 static int copy_counters_to_user(struct ebt_table *t,
1378                                   const struct ebt_counter *oldcounters,
1379                                   void __user *user, unsigned int num_counters,
1380                                   unsigned int nentries)
1381 {
1382         struct ebt_counter *counterstmp;
1383         int ret = 0;
1384
1385         /* userspace might not need the counters */
1386         if (num_counters == 0)
1387                 return 0;
1388
1389         if (num_counters != nentries) {
1390                 BUGPRINT("Num_counters wrong\n");
1391                 return -EINVAL;
1392         }
1393
1394         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1395         if (!counterstmp)
1396                 return -ENOMEM;
1397
1398         write_lock_bh(&t->lock);
1399         get_counters(oldcounters, counterstmp, nentries);
1400         write_unlock_bh(&t->lock);
1401
1402         if (copy_to_user(user, counterstmp,
1403            nentries * sizeof(struct ebt_counter)))
1404                 ret = -EFAULT;
1405         vfree(counterstmp);
1406         return ret;
1407 }
1408
1409 /* called with ebt_mutex locked */
1410 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1411     const int *len, int cmd)
1412 {
1413         struct ebt_replace tmp;
1414         const struct ebt_counter *oldcounters;
1415         unsigned int entries_size, nentries;
1416         int ret;
1417         char *entries;
1418
1419         if (cmd == EBT_SO_GET_ENTRIES) {
1420                 entries_size = t->private->entries_size;
1421                 nentries = t->private->nentries;
1422                 entries = t->private->entries;
1423                 oldcounters = t->private->counters;
1424         } else {
1425                 entries_size = t->table->entries_size;
1426                 nentries = t->table->nentries;
1427                 entries = t->table->entries;
1428                 oldcounters = t->table->counters;
1429         }
1430
1431         if (copy_from_user(&tmp, user, sizeof(tmp)))
1432                 return -EFAULT;
1433
1434         if (*len != sizeof(struct ebt_replace) + entries_size +
1435            (tmp.num_counters? nentries * sizeof(struct ebt_counter): 0))
1436                 return -EINVAL;
1437
1438         if (tmp.nentries != nentries) {
1439                 BUGPRINT("Nentries wrong\n");
1440                 return -EINVAL;
1441         }
1442
1443         if (tmp.entries_size != entries_size) {
1444                 BUGPRINT("Wrong size\n");
1445                 return -EINVAL;
1446         }
1447
1448         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1449                                         tmp.num_counters, nentries);
1450         if (ret)
1451                 return ret;
1452
1453         if (copy_to_user(tmp.entries, entries, entries_size)) {
1454                 BUGPRINT("Couldn't copy entries to userspace\n");
1455                 return -EFAULT;
1456         }
1457         /* set the match/watcher/target names right */
1458         return EBT_ENTRY_ITERATE(entries, entries_size,
1459            ebt_make_names, entries, tmp.entries);
1460 }
1461
1462 static int do_ebt_set_ctl(struct sock *sk,
1463         int cmd, void __user *user, unsigned int len)
1464 {
1465         int ret;
1466
1467         if (!capable(CAP_NET_ADMIN))
1468                 return -EPERM;
1469
1470         switch(cmd) {
1471         case EBT_SO_SET_ENTRIES:
1472                 ret = do_replace(sock_net(sk), user, len);
1473                 break;
1474         case EBT_SO_SET_COUNTERS:
1475                 ret = update_counters(sock_net(sk), user, len);
1476                 break;
1477         default:
1478                 ret = -EINVAL;
1479         }
1480         return ret;
1481 }
1482
1483 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1484 {
1485         int ret;
1486         struct ebt_replace tmp;
1487         struct ebt_table *t;
1488
1489         if (!capable(CAP_NET_ADMIN))
1490                 return -EPERM;
1491
1492         if (copy_from_user(&tmp, user, sizeof(tmp)))
1493                 return -EFAULT;
1494
1495         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
1496         if (!t)
1497                 return ret;
1498
1499         switch(cmd) {
1500         case EBT_SO_GET_INFO:
1501         case EBT_SO_GET_INIT_INFO:
1502                 if (*len != sizeof(struct ebt_replace)){
1503                         ret = -EINVAL;
1504                         mutex_unlock(&ebt_mutex);
1505                         break;
1506                 }
1507                 if (cmd == EBT_SO_GET_INFO) {
1508                         tmp.nentries = t->private->nentries;
1509                         tmp.entries_size = t->private->entries_size;
1510                         tmp.valid_hooks = t->valid_hooks;
1511                 } else {
1512                         tmp.nentries = t->table->nentries;
1513                         tmp.entries_size = t->table->entries_size;
1514                         tmp.valid_hooks = t->table->valid_hooks;
1515                 }
1516                 mutex_unlock(&ebt_mutex);
1517                 if (copy_to_user(user, &tmp, *len) != 0){
1518                         BUGPRINT("c2u Didn't work\n");
1519                         ret = -EFAULT;
1520                         break;
1521                 }
1522                 ret = 0;
1523                 break;
1524
1525         case EBT_SO_GET_ENTRIES:
1526         case EBT_SO_GET_INIT_ENTRIES:
1527                 ret = copy_everything_to_user(t, user, len, cmd);
1528                 mutex_unlock(&ebt_mutex);
1529                 break;
1530
1531         default:
1532                 mutex_unlock(&ebt_mutex);
1533                 ret = -EINVAL;
1534         }
1535
1536         return ret;
1537 }
1538
1539 #ifdef CONFIG_COMPAT
1540 /* 32 bit-userspace compatibility definitions. */
1541 struct compat_ebt_replace {
1542         char name[EBT_TABLE_MAXNAMELEN];
1543         compat_uint_t valid_hooks;
1544         compat_uint_t nentries;
1545         compat_uint_t entries_size;
1546         /* start of the chains */
1547         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1548         /* nr of counters userspace expects back */
1549         compat_uint_t num_counters;
1550         /* where the kernel will put the old counters. */
1551         compat_uptr_t counters;
1552         compat_uptr_t entries;
1553 };
1554
1555 /* struct ebt_entry_match, _target and _watcher have same layout */
1556 struct compat_ebt_entry_mwt {
1557         union {
1558                 char name[EBT_FUNCTION_MAXNAMELEN];
1559                 compat_uptr_t ptr;
1560         } u;
1561         compat_uint_t match_size;
1562         compat_uint_t data[0];
1563 };
1564
1565 /* account for possible padding between match_size and ->data */
1566 static int ebt_compat_entry_padsize(void)
1567 {
1568         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1569                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1570         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1571                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1572 }
1573
1574 static int ebt_compat_match_offset(const struct xt_match *match,
1575                                    unsigned int userlen)
1576 {
1577         /*
1578          * ebt_among needs special handling. The kernel .matchsize is
1579          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1580          * value is expected.
1581          * Example: userspace sends 4500, ebt_among.c wants 4504.
1582          */
1583         if (unlikely(match->matchsize == -1))
1584                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1585         return xt_compat_match_offset(match);
1586 }
1587
1588 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1589                                 unsigned int *size)
1590 {
1591         const struct xt_match *match = m->u.match;
1592         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1593         int off = ebt_compat_match_offset(match, m->match_size);
1594         compat_uint_t msize = m->match_size - off;
1595
1596         BUG_ON(off >= m->match_size);
1597
1598         if (copy_to_user(cm->u.name, match->name,
1599             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1600                 return -EFAULT;
1601
1602         if (match->compat_to_user) {
1603                 if (match->compat_to_user(cm->data, m->data))
1604                         return -EFAULT;
1605         } else if (copy_to_user(cm->data, m->data, msize))
1606                         return -EFAULT;
1607
1608         *size -= ebt_compat_entry_padsize() + off;
1609         *dstptr = cm->data;
1610         *dstptr += msize;
1611         return 0;
1612 }
1613
1614 static int compat_target_to_user(struct ebt_entry_target *t,
1615                                  void __user **dstptr,
1616                                  unsigned int *size)
1617 {
1618         const struct xt_target *target = t->u.target;
1619         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1620         int off = xt_compat_target_offset(target);
1621         compat_uint_t tsize = t->target_size - off;
1622
1623         BUG_ON(off >= t->target_size);
1624
1625         if (copy_to_user(cm->u.name, target->name,
1626             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1627                 return -EFAULT;
1628
1629         if (target->compat_to_user) {
1630                 if (target->compat_to_user(cm->data, t->data))
1631                         return -EFAULT;
1632         } else if (copy_to_user(cm->data, t->data, tsize))
1633                 return -EFAULT;
1634
1635         *size -= ebt_compat_entry_padsize() + off;
1636         *dstptr = cm->data;
1637         *dstptr += tsize;
1638         return 0;
1639 }
1640
1641 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1642                                   void __user **dstptr,
1643                                   unsigned int *size)
1644 {
1645         return compat_target_to_user((struct ebt_entry_target *)w,
1646                                                         dstptr, size);
1647 }
1648
1649 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1650                                 unsigned int *size)
1651 {
1652         struct ebt_entry_target *t;
1653         struct ebt_entry __user *ce;
1654         u32 watchers_offset, target_offset, next_offset;
1655         compat_uint_t origsize;
1656         int ret;
1657
1658         if (e->bitmask == 0) {
1659                 if (*size < sizeof(struct ebt_entries))
1660                         return -EINVAL;
1661                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1662                         return -EFAULT;
1663
1664                 *dstptr += sizeof(struct ebt_entries);
1665                 *size -= sizeof(struct ebt_entries);
1666                 return 0;
1667         }
1668
1669         if (*size < sizeof(*ce))
1670                 return -EINVAL;
1671
1672         ce = (struct ebt_entry __user *)*dstptr;
1673         if (copy_to_user(ce, e, sizeof(*ce)))
1674                 return -EFAULT;
1675
1676         origsize = *size;
1677         *dstptr += sizeof(*ce);
1678
1679         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1680         if (ret)
1681                 return ret;
1682         watchers_offset = e->watchers_offset - (origsize - *size);
1683
1684         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1685         if (ret)
1686                 return ret;
1687         target_offset = e->target_offset - (origsize - *size);
1688
1689         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1690
1691         ret = compat_target_to_user(t, dstptr, size);
1692         if (ret)
1693                 return ret;
1694         next_offset = e->next_offset - (origsize - *size);
1695
1696         if (put_user(watchers_offset, &ce->watchers_offset) ||
1697             put_user(target_offset, &ce->target_offset) ||
1698             put_user(next_offset, &ce->next_offset))
1699                 return -EFAULT;
1700
1701         *size -= sizeof(*ce);
1702         return 0;
1703 }
1704
1705 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1706 {
1707         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1708         *off += ebt_compat_entry_padsize();
1709         return 0;
1710 }
1711
1712 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1713 {
1714         *off += xt_compat_target_offset(w->u.watcher);
1715         *off += ebt_compat_entry_padsize();
1716         return 0;
1717 }
1718
1719 static int compat_calc_entry(const struct ebt_entry *e,
1720                              const struct ebt_table_info *info,
1721                              const void *base,
1722                              struct compat_ebt_replace *newinfo)
1723 {
1724         const struct ebt_entry_target *t;
1725         unsigned int entry_offset;
1726         int off, ret, i;
1727
1728         if (e->bitmask == 0)
1729                 return 0;
1730
1731         off = 0;
1732         entry_offset = (void *)e - base;
1733
1734         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1735         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1736
1737         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1738
1739         off += xt_compat_target_offset(t->u.target);
1740         off += ebt_compat_entry_padsize();
1741
1742         newinfo->entries_size -= off;
1743
1744         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1745         if (ret)
1746                 return ret;
1747
1748         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1749                 const void *hookptr = info->hook_entry[i];
1750                 if (info->hook_entry[i] &&
1751                     (e < (struct ebt_entry *)(base - hookptr))) {
1752                         newinfo->hook_entry[i] -= off;
1753                         pr_debug("0x%08X -> 0x%08X\n",
1754                                         newinfo->hook_entry[i] + off,
1755                                         newinfo->hook_entry[i]);
1756                 }
1757         }
1758
1759         return 0;
1760 }
1761
1762
1763 static int compat_table_info(const struct ebt_table_info *info,
1764                              struct compat_ebt_replace *newinfo)
1765 {
1766         unsigned int size = info->entries_size;
1767         const void *entries = info->entries;
1768
1769         newinfo->entries_size = size;
1770
1771         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1772                                                         entries, newinfo);
1773 }
1774
1775 static int compat_copy_everything_to_user(struct ebt_table *t,
1776                                           void __user *user, int *len, int cmd)
1777 {
1778         struct compat_ebt_replace repl, tmp;
1779         struct ebt_counter *oldcounters;
1780         struct ebt_table_info tinfo;
1781         int ret;
1782         void __user *pos;
1783
1784         memset(&tinfo, 0, sizeof(tinfo));
1785
1786         if (cmd == EBT_SO_GET_ENTRIES) {
1787                 tinfo.entries_size = t->private->entries_size;
1788                 tinfo.nentries = t->private->nentries;
1789                 tinfo.entries = t->private->entries;
1790                 oldcounters = t->private->counters;
1791         } else {
1792                 tinfo.entries_size = t->table->entries_size;
1793                 tinfo.nentries = t->table->nentries;
1794                 tinfo.entries = t->table->entries;
1795                 oldcounters = t->table->counters;
1796         }
1797
1798         if (copy_from_user(&tmp, user, sizeof(tmp)))
1799                 return -EFAULT;
1800
1801         if (tmp.nentries != tinfo.nentries ||
1802            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1803                 return -EINVAL;
1804
1805         memcpy(&repl, &tmp, sizeof(repl));
1806         if (cmd == EBT_SO_GET_ENTRIES)
1807                 ret = compat_table_info(t->private, &repl);
1808         else
1809                 ret = compat_table_info(&tinfo, &repl);
1810         if (ret)
1811                 return ret;
1812
1813         if (*len != sizeof(tmp) + repl.entries_size +
1814            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1815                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1816                                 *len, tinfo.entries_size, repl.entries_size);
1817                 return -EINVAL;
1818         }
1819
1820         /* userspace might not need the counters */
1821         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1822                                         tmp.num_counters, tinfo.nentries);
1823         if (ret)
1824                 return ret;
1825
1826         pos = compat_ptr(tmp.entries);
1827         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1828                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1829 }
1830
1831 struct ebt_entries_buf_state {
1832         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1833         u32 buf_kern_len;       /* total size of kernel buffer */
1834         u32 buf_kern_offset;    /* amount of data copied so far */
1835         u32 buf_user_offset;    /* read position in userspace buffer */
1836 };
1837
1838 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1839 {
1840         state->buf_kern_offset += sz;
1841         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1842 }
1843
1844 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1845                        void *data, unsigned int sz)
1846 {
1847         if (state->buf_kern_start == NULL)
1848                 goto count_only;
1849
1850         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1851
1852         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1853
1854  count_only:
1855         state->buf_user_offset += sz;
1856         return ebt_buf_count(state, sz);
1857 }
1858
1859 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1860 {
1861         char *b = state->buf_kern_start;
1862
1863         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1864
1865         if (b != NULL && sz > 0)
1866                 memset(b + state->buf_kern_offset, 0, sz);
1867         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1868         return ebt_buf_count(state, sz);
1869 }
1870
1871 enum compat_mwt {
1872         EBT_COMPAT_MATCH,
1873         EBT_COMPAT_WATCHER,
1874         EBT_COMPAT_TARGET,
1875 };
1876
1877 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1878                                 enum compat_mwt compat_mwt,
1879                                 struct ebt_entries_buf_state *state,
1880                                 const unsigned char *base)
1881 {
1882         char name[EBT_FUNCTION_MAXNAMELEN];
1883         struct xt_match *match;
1884         struct xt_target *wt;
1885         void *dst = NULL;
1886         int off, pad = 0, ret = 0;
1887         unsigned int size_kern, entry_offset, match_size = mwt->match_size;
1888
1889         strlcpy(name, mwt->u.name, sizeof(name));
1890
1891         if (state->buf_kern_start)
1892                 dst = state->buf_kern_start + state->buf_kern_offset;
1893
1894         entry_offset = (unsigned char *) mwt - base;
1895         switch (compat_mwt) {
1896         case EBT_COMPAT_MATCH:
1897                 match = try_then_request_module(xt_find_match(NFPROTO_BRIDGE,
1898                                                 name, 0), "ebt_%s", name);
1899                 if (match == NULL)
1900                         return -ENOENT;
1901                 if (IS_ERR(match))
1902                         return PTR_ERR(match);
1903
1904                 off = ebt_compat_match_offset(match, match_size);
1905                 if (dst) {
1906                         if (match->compat_from_user)
1907                                 match->compat_from_user(dst, mwt->data);
1908                         else
1909                                 memcpy(dst, mwt->data, match_size);
1910                 }
1911
1912                 size_kern = match->matchsize;
1913                 if (unlikely(size_kern == -1))
1914                         size_kern = match_size;
1915                 module_put(match->me);
1916                 break;
1917         case EBT_COMPAT_WATCHER: /* fallthrough */
1918         case EBT_COMPAT_TARGET:
1919                 wt = try_then_request_module(xt_find_target(NFPROTO_BRIDGE,
1920                                                 name, 0), "ebt_%s", name);
1921                 if (wt == NULL)
1922                         return -ENOENT;
1923                 if (IS_ERR(wt))
1924                         return PTR_ERR(wt);
1925                 off = xt_compat_target_offset(wt);
1926
1927                 if (dst) {
1928                         if (wt->compat_from_user)
1929                                 wt->compat_from_user(dst, mwt->data);
1930                         else
1931                                 memcpy(dst, mwt->data, match_size);
1932                 }
1933
1934                 size_kern = wt->targetsize;
1935                 module_put(wt->me);
1936                 break;
1937         }
1938
1939         if (!dst) {
1940                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset,
1941                                         off + ebt_compat_entry_padsize());
1942                 if (ret < 0)
1943                         return ret;
1944         }
1945
1946         state->buf_kern_offset += match_size + off;
1947         state->buf_user_offset += match_size;
1948         pad = XT_ALIGN(size_kern) - size_kern;
1949
1950         if (pad > 0 && dst) {
1951                 BUG_ON(state->buf_kern_len <= pad);
1952                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1953                 memset(dst + size_kern, 0, pad);
1954         }
1955         return off + match_size;
1956 }
1957
1958 /*
1959  * return size of all matches, watchers or target, including necessary
1960  * alignment and padding.
1961  */
1962 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1963                         unsigned int size_left, enum compat_mwt type,
1964                         struct ebt_entries_buf_state *state, const void *base)
1965 {
1966         int growth = 0;
1967         char *buf;
1968
1969         if (size_left == 0)
1970                 return 0;
1971
1972         buf = (char *) match32;
1973
1974         while (size_left >= sizeof(*match32)) {
1975                 struct ebt_entry_match *match_kern;
1976                 int ret;
1977
1978                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1979                 if (match_kern) {
1980                         char *tmp;
1981                         tmp = state->buf_kern_start + state->buf_kern_offset;
1982                         match_kern = (struct ebt_entry_match *) tmp;
1983                 }
1984                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1985                 if (ret < 0)
1986                         return ret;
1987                 size_left -= sizeof(*match32);
1988
1989                 /* add padding before match->data (if any) */
1990                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1991                 if (ret < 0)
1992                         return ret;
1993
1994                 if (match32->match_size > size_left)
1995                         return -EINVAL;
1996
1997                 size_left -= match32->match_size;
1998
1999                 ret = compat_mtw_from_user(match32, type, state, base);
2000                 if (ret < 0)
2001                         return ret;
2002
2003                 BUG_ON(ret < match32->match_size);
2004                 growth += ret - match32->match_size;
2005                 growth += ebt_compat_entry_padsize();
2006
2007                 buf += sizeof(*match32);
2008                 buf += match32->match_size;
2009
2010                 if (match_kern)
2011                         match_kern->match_size = ret;
2012
2013                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2014                 match32 = (struct compat_ebt_entry_mwt *) buf;
2015         }
2016
2017         return growth;
2018 }
2019
2020 #define EBT_COMPAT_WATCHER_ITERATE(e, fn, args...)          \
2021 ({                                                          \
2022         unsigned int __i;                                   \
2023         int __ret = 0;                                      \
2024         struct compat_ebt_entry_mwt *__watcher;             \
2025                                                             \
2026         for (__i = e->watchers_offset;                      \
2027              __i < (e)->target_offset;                      \
2028              __i += __watcher->watcher_size +               \
2029              sizeof(struct compat_ebt_entry_mwt)) {         \
2030                 __watcher = (void *)(e) + __i;              \
2031                 __ret = fn(__watcher , ## args);            \
2032                 if (__ret != 0)                             \
2033                         break;                              \
2034         }                                                   \
2035         if (__ret == 0) {                                   \
2036                 if (__i != (e)->target_offset)              \
2037                         __ret = -EINVAL;                    \
2038         }                                                   \
2039         __ret;                                              \
2040 })
2041
2042 #define EBT_COMPAT_MATCH_ITERATE(e, fn, args...)            \
2043 ({                                                          \
2044         unsigned int __i;                                   \
2045         int __ret = 0;                                      \
2046         struct compat_ebt_entry_mwt *__match;               \
2047                                                             \
2048         for (__i = sizeof(struct ebt_entry);                \
2049              __i < (e)->watchers_offset;                    \
2050              __i += __match->match_size +                   \
2051              sizeof(struct compat_ebt_entry_mwt)) {         \
2052                 __match = (void *)(e) + __i;                \
2053                 __ret = fn(__match , ## args);              \
2054                 if (__ret != 0)                             \
2055                         break;                              \
2056         }                                                   \
2057         if (__ret == 0) {                                   \
2058                 if (__i != (e)->watchers_offset)            \
2059                         __ret = -EINVAL;                    \
2060         }                                                   \
2061         __ret;                                              \
2062 })
2063
2064 /* called for all ebt_entry structures. */
2065 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2066                           unsigned int *total,
2067                           struct ebt_entries_buf_state *state)
2068 {
2069         unsigned int i, j, startoff, new_offset = 0;
2070         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2071         unsigned int offsets[4];
2072         unsigned int *offsets_update = NULL;
2073         int ret;
2074         char *buf_start;
2075
2076         if (*total < sizeof(struct ebt_entries))
2077                 return -EINVAL;
2078
2079         if (!entry->bitmask) {
2080                 *total -= sizeof(struct ebt_entries);
2081                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2082         }
2083         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2084                 return -EINVAL;
2085
2086         startoff = state->buf_user_offset;
2087         /* pull in most part of ebt_entry, it does not need to be changed. */
2088         ret = ebt_buf_add(state, entry,
2089                         offsetof(struct ebt_entry, watchers_offset));
2090         if (ret < 0)
2091                 return ret;
2092
2093         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2094         memcpy(&offsets[1], &entry->watchers_offset,
2095                         sizeof(offsets) - sizeof(offsets[0]));
2096
2097         if (state->buf_kern_start) {
2098                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2099                 offsets_update = (unsigned int *) buf_start;
2100         }
2101         ret = ebt_buf_add(state, &offsets[1],
2102                         sizeof(offsets) - sizeof(offsets[0]));
2103         if (ret < 0)
2104                 return ret;
2105         buf_start = (char *) entry;
2106         /*
2107          * 0: matches offset, always follows ebt_entry.
2108          * 1: watchers offset, from ebt_entry structure
2109          * 2: target offset, from ebt_entry structure
2110          * 3: next ebt_entry offset, from ebt_entry structure
2111          *
2112          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2113          */
2114         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2115                 struct compat_ebt_entry_mwt *match32;
2116                 unsigned int size;
2117                 char *buf = buf_start;
2118
2119                 buf = buf_start + offsets[i];
2120                 if (offsets[i] > offsets[j])
2121                         return -EINVAL;
2122
2123                 match32 = (struct compat_ebt_entry_mwt *) buf;
2124                 size = offsets[j] - offsets[i];
2125                 ret = ebt_size_mwt(match32, size, i, state, base);
2126                 if (ret < 0)
2127                         return ret;
2128                 new_offset += ret;
2129                 if (offsets_update && new_offset) {
2130                         pr_debug("ebtables: change offset %d to %d\n",
2131                                 offsets_update[i], offsets[j] + new_offset);
2132                         offsets_update[i] = offsets[j] + new_offset;
2133                 }
2134         }
2135
2136         startoff = state->buf_user_offset - startoff;
2137
2138         BUG_ON(*total < startoff);
2139         *total -= startoff;
2140         return 0;
2141 }
2142
2143 /*
2144  * repl->entries_size is the size of the ebt_entry blob in userspace.
2145  * It might need more memory when copied to a 64 bit kernel in case
2146  * userspace is 32-bit. So, first task: find out how much memory is needed.
2147  *
2148  * Called before validation is performed.
2149  */
2150 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2151                                 struct ebt_entries_buf_state *state)
2152 {
2153         unsigned int size_remaining = size_user;
2154         int ret;
2155
2156         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2157                                         &size_remaining, state);
2158         if (ret < 0)
2159                 return ret;
2160
2161         WARN_ON(size_remaining);
2162         return state->buf_kern_offset;
2163 }
2164
2165
2166 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2167                                             void __user *user, unsigned int len)
2168 {
2169         struct compat_ebt_replace tmp;
2170         int i;
2171
2172         if (len < sizeof(tmp))
2173                 return -EINVAL;
2174
2175         if (copy_from_user(&tmp, user, sizeof(tmp)))
2176                 return -EFAULT;
2177
2178         if (len != sizeof(tmp) + tmp.entries_size)
2179                 return -EINVAL;
2180
2181         if (tmp.entries_size == 0)
2182                 return -EINVAL;
2183
2184         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2185                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2186                 return -ENOMEM;
2187         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2188                 return -ENOMEM;
2189
2190         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2191
2192         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2193         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2194                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2195
2196         repl->num_counters = tmp.num_counters;
2197         repl->counters = compat_ptr(tmp.counters);
2198         repl->entries = compat_ptr(tmp.entries);
2199         return 0;
2200 }
2201
2202 static int compat_do_replace(struct net *net, void __user *user,
2203                              unsigned int len)
2204 {
2205         int ret, i, countersize, size64;
2206         struct ebt_table_info *newinfo;
2207         struct ebt_replace tmp;
2208         struct ebt_entries_buf_state state;
2209         void *entries_tmp;
2210
2211         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2212         if (ret) {
2213                 /* try real handler in case userland supplied needed padding */
2214                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2215                         ret = 0;
2216                 return ret;
2217         }
2218
2219         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2220         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2221         if (!newinfo)
2222                 return -ENOMEM;
2223
2224         if (countersize)
2225                 memset(newinfo->counters, 0, countersize);
2226
2227         memset(&state, 0, sizeof(state));
2228
2229         newinfo->entries = vmalloc(tmp.entries_size);
2230         if (!newinfo->entries) {
2231                 ret = -ENOMEM;
2232                 goto free_newinfo;
2233         }
2234         if (copy_from_user(
2235            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2236                 ret = -EFAULT;
2237                 goto free_entries;
2238         }
2239
2240         entries_tmp = newinfo->entries;
2241
2242         xt_compat_lock(NFPROTO_BRIDGE);
2243
2244         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2245         if (ret < 0)
2246                 goto out_unlock;
2247
2248         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2249                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2250                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2251
2252         size64 = ret;
2253         newinfo->entries = vmalloc(size64);
2254         if (!newinfo->entries) {
2255                 vfree(entries_tmp);
2256                 ret = -ENOMEM;
2257                 goto out_unlock;
2258         }
2259
2260         memset(&state, 0, sizeof(state));
2261         state.buf_kern_start = newinfo->entries;
2262         state.buf_kern_len = size64;
2263
2264         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2265         BUG_ON(ret < 0);        /* parses same data again */
2266
2267         vfree(entries_tmp);
2268         tmp.entries_size = size64;
2269
2270         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2271                 char __user *usrptr;
2272                 if (tmp.hook_entry[i]) {
2273                         unsigned int delta;
2274                         usrptr = (char __user *) tmp.hook_entry[i];
2275                         delta = usrptr - tmp.entries;
2276                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2277                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2278                 }
2279         }
2280
2281         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2282         xt_compat_unlock(NFPROTO_BRIDGE);
2283
2284         ret = do_replace_finish(net, &tmp, newinfo);
2285         if (ret == 0)
2286                 return ret;
2287 free_entries:
2288         vfree(newinfo->entries);
2289 free_newinfo:
2290         vfree(newinfo);
2291         return ret;
2292 out_unlock:
2293         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2294         xt_compat_unlock(NFPROTO_BRIDGE);
2295         goto free_entries;
2296 }
2297
2298 static int compat_update_counters(struct net *net, void __user *user,
2299                                   unsigned int len)
2300 {
2301         struct compat_ebt_replace hlp;
2302
2303         if (copy_from_user(&hlp, user, sizeof(hlp)))
2304                 return -EFAULT;
2305
2306         /* try real handler in case userland supplied needed padding */
2307         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2308                 return update_counters(net, user, len);
2309
2310         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2311                                         hlp.num_counters, user, len);
2312 }
2313
2314 static int compat_do_ebt_set_ctl(struct sock *sk,
2315                 int cmd, void __user *user, unsigned int len)
2316 {
2317         int ret;
2318
2319         if (!capable(CAP_NET_ADMIN))
2320                 return -EPERM;
2321
2322         switch (cmd) {
2323         case EBT_SO_SET_ENTRIES:
2324                 ret = compat_do_replace(sock_net(sk), user, len);
2325                 break;
2326         case EBT_SO_SET_COUNTERS:
2327                 ret = compat_update_counters(sock_net(sk), user, len);
2328                 break;
2329         default:
2330                 ret = -EINVAL;
2331   }
2332         return ret;
2333 }
2334
2335 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2336                 void __user *user, int *len)
2337 {
2338         int ret;
2339         struct compat_ebt_replace tmp;
2340         struct ebt_table *t;
2341
2342         if (!capable(CAP_NET_ADMIN))
2343                 return -EPERM;
2344
2345         /* try real handler in case userland supplied needed padding */
2346         if ((cmd == EBT_SO_GET_INFO ||
2347              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2348                         return do_ebt_get_ctl(sk, cmd, user, len);
2349
2350         if (copy_from_user(&tmp, user, sizeof(tmp)))
2351                 return -EFAULT;
2352
2353         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
2354         if (!t)
2355                 return ret;
2356
2357         xt_compat_lock(NFPROTO_BRIDGE);
2358         switch (cmd) {
2359         case EBT_SO_GET_INFO:
2360                 tmp.nentries = t->private->nentries;
2361                 ret = compat_table_info(t->private, &tmp);
2362                 if (ret)
2363                         goto out;
2364                 tmp.valid_hooks = t->valid_hooks;
2365
2366                 if (copy_to_user(user, &tmp, *len) != 0) {
2367                         ret = -EFAULT;
2368                         break;
2369                 }
2370                 ret = 0;
2371                 break;
2372         case EBT_SO_GET_INIT_INFO:
2373                 tmp.nentries = t->table->nentries;
2374                 tmp.entries_size = t->table->entries_size;
2375                 tmp.valid_hooks = t->table->valid_hooks;
2376
2377                 if (copy_to_user(user, &tmp, *len) != 0) {
2378                         ret = -EFAULT;
2379                         break;
2380                 }
2381                 ret = 0;
2382                 break;
2383         case EBT_SO_GET_ENTRIES:
2384         case EBT_SO_GET_INIT_ENTRIES:
2385                 /*
2386                  * try real handler first in case of userland-side padding.
2387                  * in case we are dealing with an 'ordinary' 32 bit binary
2388                  * without 64bit compatibility padding, this will fail right
2389                  * after copy_from_user when the *len argument is validated.
2390                  *
2391                  * the compat_ variant needs to do one pass over the kernel
2392                  * data set to adjust for size differences before it the check.
2393                  */
2394                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2395                         ret = 0;
2396                 else
2397                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2398                 break;
2399         default:
2400                 ret = -EINVAL;
2401         }
2402  out:
2403         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2404         xt_compat_unlock(NFPROTO_BRIDGE);
2405         mutex_unlock(&ebt_mutex);
2406         return ret;
2407 }
2408 #endif
2409
2410 static struct nf_sockopt_ops ebt_sockopts =
2411 {
2412         .pf             = PF_INET,
2413         .set_optmin     = EBT_BASE_CTL,
2414         .set_optmax     = EBT_SO_SET_MAX + 1,
2415         .set            = do_ebt_set_ctl,
2416 #ifdef CONFIG_COMPAT
2417         .compat_set     = compat_do_ebt_set_ctl,
2418 #endif
2419         .get_optmin     = EBT_BASE_CTL,
2420         .get_optmax     = EBT_SO_GET_MAX + 1,
2421         .get            = do_ebt_get_ctl,
2422 #ifdef CONFIG_COMPAT
2423         .compat_get     = compat_do_ebt_get_ctl,
2424 #endif
2425         .owner          = THIS_MODULE,
2426 };
2427
2428 static int __init ebtables_init(void)
2429 {
2430         int ret;
2431
2432         ret = xt_register_target(&ebt_standard_target);
2433         if (ret < 0)
2434                 return ret;
2435         ret = nf_register_sockopt(&ebt_sockopts);
2436         if (ret < 0) {
2437                 xt_unregister_target(&ebt_standard_target);
2438                 return ret;
2439         }
2440
2441         printk(KERN_INFO "Ebtables v2.0 registered\n");
2442         return 0;
2443 }
2444
2445 static void __exit ebtables_fini(void)
2446 {
2447         nf_unregister_sockopt(&ebt_sockopts);
2448         xt_unregister_target(&ebt_standard_target);
2449         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2450 }
2451
2452 EXPORT_SYMBOL(ebt_register_table);
2453 EXPORT_SYMBOL(ebt_unregister_table);
2454 EXPORT_SYMBOL(ebt_do_table);
2455 module_init(ebtables_init);
2456 module_exit(ebtables_fini);
2457 MODULE_LICENSE("GPL");