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 strongly inspired by 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <asm/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  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_action_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
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 /* Do some firewalling */
 181 unsigned int ebt_do_table(struct sk_buff *skb,
 182                           const struct nf_hook_state *state,
 183                           struct ebt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         int i, nentries;
 187         struct ebt_entry *point;
 188         struct ebt_counter *counter_base, *cb_base;
 189         const struct ebt_entry_target *t;
 190         int verdict, sp = 0;
 191         struct ebt_chainstack *cs;
 192         struct ebt_entries *chaininfo;
 193         const char *base;
 194         const struct ebt_table_info *private;
 195         struct xt_action_param acpar;
 196
 197         acpar.family  = NFPROTO_BRIDGE;
 198         acpar.net     = state->net;
 199         acpar.in      = state->in;
 200         acpar.out     = state->out;
 201         acpar.hotdrop = false;
 202         acpar.hooknum = hook;
 203
 204         read_lock_bh(&table->lock);
 205         private = table->private;
 206         cb_base = COUNTER_BASE(private->counters, private->nentries,
 207            smp_processor_id());
 208         if (private->chainstack)
 209                 cs = private->chainstack[smp_processor_id()];
 210         else
 211                 cs = NULL;
 212         chaininfo = private->hook_entry[hook];
 213         nentries = private->hook_entry[hook]->nentries;
 214         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 215         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 216         /* base for chain jumps */
 217         base = private->entries;
 218         i = 0;
 219         while (i < nentries) {
 220                 if (ebt_basic_match(point, skb, state->in, state->out))
 221                         goto letscontinue;
 222
 223                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 224                         goto letscontinue;
 225                 if (acpar.hotdrop) {
 226                         read_unlock_bh(&table->lock);
 227                         return NF_DROP;
 228                 }
 229
 230                 /* increase counter */
 231                 (*(counter_base + i)).pcnt++;
 232                 (*(counter_base + i)).bcnt += skb->len;
 233
 234                 /* these should only watch: not modify, nor tell us
 235                  * what to do with the packet
 236                  */
 237                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 238
 239                 t = (struct ebt_entry_target *)
 240                    (((char *)point) + point->target_offset);
 241                 /* standard target */
 242                 if (!t->u.target->target)
 243                         verdict = ((struct ebt_standard_target *)t)->verdict;
 244                 else {
 245                         acpar.target   = t->u.target;
 246                         acpar.targinfo = t->data;
 247                         verdict = t->u.target->target(skb, &acpar);
 248                 }
 249                 if (verdict == EBT_ACCEPT) {
 250                         read_unlock_bh(&table->lock);
 251                         return NF_ACCEPT;
 252                 }
 253                 if (verdict == EBT_DROP) {
 254                         read_unlock_bh(&table->lock);
 255                         return NF_DROP;
 256                 }
 257                 if (verdict == EBT_RETURN) {
 258 letsreturn:
 259 #ifdef CONFIG_NETFILTER_DEBUG
 260                         if (sp == 0) {
 261                                 BUGPRINT("RETURN on base chain");
 262                                 /* act like this is EBT_CONTINUE */
 263                                 goto letscontinue;
 264                         }
 265 #endif
 266                         sp--;
 267                         /* put all the local variables right */
 268                         i = cs[sp].n;
 269                         chaininfo = cs[sp].chaininfo;
 270                         nentries = chaininfo->nentries;
 271                         point = cs[sp].e;
 272                         counter_base = cb_base +
 273                            chaininfo->counter_offset;
 274                         continue;
 275                 }
 276                 if (verdict == EBT_CONTINUE)
 277                         goto letscontinue;
 278 #ifdef CONFIG_NETFILTER_DEBUG
 279                 if (verdict < 0) {
 280                         BUGPRINT("bogus standard verdict\n");
 281                         read_unlock_bh(&table->lock);
 282                         return NF_DROP;
 283                 }
 284 #endif
 285                 /* jump to a udc */
 286                 cs[sp].n = i + 1;
 287                 cs[sp].chaininfo = chaininfo;
 288                 cs[sp].e = ebt_next_entry(point);
 289                 i = 0;
 290                 chaininfo = (struct ebt_entries *) (base + verdict);
 291 #ifdef CONFIG_NETFILTER_DEBUG
 292                 if (chaininfo->distinguisher) {
 293                         BUGPRINT("jump to non-chain\n");
 294                         read_unlock_bh(&table->lock);
 295                         return NF_DROP;
 296                 }
 297 #endif
 298                 nentries = chaininfo->nentries;
 299                 point = (struct ebt_entry *)chaininfo->data;
 300                 counter_base = cb_base + chaininfo->counter_offset;
 301                 sp++;
 302                 continue;
 303 letscontinue:
 304                 point = ebt_next_entry(point);
 305                 i++;
 306         }
 307
 308         /* I actually like this :) */
 309         if (chaininfo->policy == EBT_RETURN)
 310                 goto letsreturn;
 311         if (chaininfo->policy == EBT_ACCEPT) {
 312                 read_unlock_bh(&table->lock);
 313                 return NF_ACCEPT;
 314         }
 315         read_unlock_bh(&table->lock);
 316         return NF_DROP;
 317 }
 318
 319 /* If it succeeds, returns element and locks mutex */
 320 static inline void *
 321 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 322                         struct mutex *mutex)
 323 {
 324         struct {
 325                 struct list_head list;
 326                 char name[EBT_FUNCTION_MAXNAMELEN];
 327         } *e;
 328
 329         mutex_lock(mutex);
 330         list_for_each_entry(e, head, list) {
 331                 if (strcmp(e->name, name) == 0)
 332                         return e;
 333         }
 334         *error = -ENOENT;
 335         mutex_unlock(mutex);
 336         return NULL;
 337 }
 338
 339 static void *
 340 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 341                  int *error, struct mutex *mutex)
 342 {
 343         return try_then_request_module(
 344                         find_inlist_lock_noload(head, name, error, mutex),
 345                         "%s%s", prefix, name);
 346 }
 347
 348 static inline struct ebt_table *
 349 find_table_lock(struct net *net, const char *name, int *error,
 350                 struct mutex *mutex)
 351 {
 352         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 353                                 "ebtable_", error, mutex);
 354 }
 355
 356 static inline int
 357 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 358                 unsigned int *cnt)
 359 {
 360         const struct ebt_entry *e = par->entryinfo;
 361         struct xt_match *match;
 362         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 363         int ret;
 364
 365         if (left < sizeof(struct ebt_entry_match) ||
 366             left - sizeof(struct ebt_entry_match) < m->match_size)
 367                 return -EINVAL;
 368
 369         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 370         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 371                 if (!IS_ERR(match))
 372                         module_put(match->me);
 373                 request_module("ebt_%s", m->u.name);
 374                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 375         }
 376         if (IS_ERR(match))
 377                 return PTR_ERR(match);
 378         m->u.match = match;
 379
 380         par->match     = match;
 381         par->matchinfo = m->data;
 382         ret = xt_check_match(par, m->match_size,
 383               e->ethproto, e->invflags & EBT_IPROTO);
 384         if (ret < 0) {
 385                 module_put(match->me);
 386                 return ret;
 387         }
 388
 389         (*cnt)++;
 390         return 0;
 391 }
 392
 393 static inline int
 394 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 395                   unsigned int *cnt)
 396 {
 397         const struct ebt_entry *e = par->entryinfo;
 398         struct xt_target *watcher;
 399         size_t left = ((char *)e + e->target_offset) - (char *)w;
 400         int ret;
 401
 402         if (left < sizeof(struct ebt_entry_watcher) ||
 403            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 404                 return -EINVAL;
 405
 406         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 407         if (IS_ERR(watcher))
 408                 return PTR_ERR(watcher);
 409
 410         if (watcher->family != NFPROTO_BRIDGE) {
 411                 module_put(watcher->me);
 412                 return -ENOENT;
 413         }
 414
 415         w->u.watcher = watcher;
 416
 417         par->target   = watcher;
 418         par->targinfo = w->data;
 419         ret = xt_check_target(par, w->watcher_size,
 420               e->ethproto, e->invflags & EBT_IPROTO);
 421         if (ret < 0) {
 422                 module_put(watcher->me);
 423                 return ret;
 424         }
 425
 426         (*cnt)++;
 427         return 0;
 428 }
 429
 430 static int ebt_verify_pointers(const struct ebt_replace *repl,
 431                                struct ebt_table_info *newinfo)
 432 {
 433         unsigned int limit = repl->entries_size;
 434         unsigned int valid_hooks = repl->valid_hooks;
 435         unsigned int offset = 0;
 436         int i;
 437
 438         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 439                 newinfo->hook_entry[i] = NULL;
 440
 441         newinfo->entries_size = repl->entries_size;
 442         newinfo->nentries = repl->nentries;
 443
 444         while (offset < limit) {
 445                 size_t left = limit - offset;
 446                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 447
 448                 if (left < sizeof(unsigned int))
 449                         break;
 450
 451                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 452                         if ((valid_hooks & (1 << i)) == 0)
 453                                 continue;
 454                         if ((char __user *)repl->hook_entry[i] ==
 455                              repl->entries + offset)
 456                                 break;
 457                 }
 458
 459                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 460                         if (e->bitmask != 0) {
 461                                 /* we make userspace set this right,
 462                                  * so there is no misunderstanding
 463                                  */
 464                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 465                                          "in distinguisher\n");
 466                                 return -EINVAL;
 467                         }
 468                         if (i != NF_BR_NUMHOOKS)
 469                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 470                         if (left < sizeof(struct ebt_entries))
 471                                 break;
 472                         offset += sizeof(struct ebt_entries);
 473                 } else {
 474                         if (left < sizeof(struct ebt_entry))
 475                                 break;
 476                         if (left < e->next_offset)
 477                                 break;
 478                         if (e->next_offset < sizeof(struct ebt_entry))
 479                                 return -EINVAL;
 480                         offset += e->next_offset;
 481                 }
 482         }
 483         if (offset != limit) {
 484                 BUGPRINT("entries_size too small\n");
 485                 return -EINVAL;
 486         }
 487
 488         /* check if all valid hooks have a chain */
 489         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 490                 if (!newinfo->hook_entry[i] &&
 491                    (valid_hooks & (1 << i))) {
 492                         BUGPRINT("Valid hook without chain\n");
 493                         return -EINVAL;
 494                 }
 495         }
 496         return 0;
 497 }
 498
 499 /* this one is very careful, as it is the first function
 500  * to parse the userspace data
 501  */
 502 static inline int
 503 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 504                                const struct ebt_table_info *newinfo,
 505                                unsigned int *n, unsigned int *cnt,
 506                                unsigned int *totalcnt, unsigned int *udc_cnt)
 507 {
 508         int i;
 509
 510         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 511                 if ((void *)e == (void *)newinfo->hook_entry[i])
 512                         break;
 513         }
 514         /* beginning of a new chain
 515          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 516          */
 517         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 518                 /* this checks if the previous chain has as many entries
 519                  * as it said it has
 520                  */
 521                 if (*n != *cnt) {
 522                         BUGPRINT("nentries does not equal the nr of entries "
 523                                  "in the chain\n");
 524                         return -EINVAL;
 525                 }
 526                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 527                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 528                         /* only RETURN from udc */
 529                         if (i != NF_BR_NUMHOOKS ||
 530                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 531                                 BUGPRINT("bad policy\n");
 532                                 return -EINVAL;
 533                         }
 534                 }
 535                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 536                         (*udc_cnt)++;
 537                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 538                         BUGPRINT("counter_offset != totalcnt");
 539                         return -EINVAL;
 540                 }
 541                 *n = ((struct ebt_entries *)e)->nentries;
 542                 *cnt = 0;
 543                 return 0;
 544         }
 545         /* a plain old entry, heh */
 546         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 547            e->watchers_offset > e->target_offset ||
 548            e->target_offset >= e->next_offset) {
 549                 BUGPRINT("entry offsets not in right order\n");
 550                 return -EINVAL;
 551         }
 552         /* this is not checked anywhere else */
 553         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 554                 BUGPRINT("target size too small\n");
 555                 return -EINVAL;
 556         }
 557         (*cnt)++;
 558         (*totalcnt)++;
 559         return 0;
 560 }
 561
 562 struct ebt_cl_stack {
 563         struct ebt_chainstack cs;
 564         int from;
 565         unsigned int hookmask;
 566 };
 567
 568 /* We need these positions to check that the jumps to a different part of the
 569  * entries is a jump to the beginning of a new chain.
 570  */
 571 static inline int
 572 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 573                       unsigned int *n, struct ebt_cl_stack *udc)
 574 {
 575         int i;
 576
 577         /* we're only interested in chain starts */
 578         if (e->bitmask)
 579                 return 0;
 580         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 581                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 582                         break;
 583         }
 584         /* only care about udc */
 585         if (i != NF_BR_NUMHOOKS)
 586                 return 0;
 587
 588         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 589         /* these initialisations are depended on later in check_chainloops() */
 590         udc[*n].cs.n = 0;
 591         udc[*n].hookmask = 0;
 592
 593         (*n)++;
 594         return 0;
 595 }
 596
 597 static inline int
 598 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 599 {
 600         struct xt_mtdtor_param par;
 601
 602         if (i && (*i)-- == 0)
 603                 return 1;
 604
 605         par.net       = net;
 606         par.match     = m->u.match;
 607         par.matchinfo = m->data;
 608         par.family    = NFPROTO_BRIDGE;
 609         if (par.match->destroy != NULL)
 610                 par.match->destroy(&par);
 611         module_put(par.match->me);
 612         return 0;
 613 }
 614
 615 static inline int
 616 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 617 {
 618         struct xt_tgdtor_param par;
 619
 620         if (i && (*i)-- == 0)
 621                 return 1;
 622
 623         par.net      = net;
 624         par.target   = w->u.watcher;
 625         par.targinfo = w->data;
 626         par.family   = NFPROTO_BRIDGE;
 627         if (par.target->destroy != NULL)
 628                 par.target->destroy(&par);
 629         module_put(par.target->me);
 630         return 0;
 631 }
 632
 633 static inline int
 634 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 635 {
 636         struct xt_tgdtor_param par;
 637         struct ebt_entry_target *t;
 638
 639         if (e->bitmask == 0)
 640                 return 0;
 641         /* we're done */
 642         if (cnt && (*cnt)-- == 0)
 643                 return 1;
 644         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 645         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 646         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 647
 648         par.net      = net;
 649         par.target   = t->u.target;
 650         par.targinfo = t->data;
 651         par.family   = NFPROTO_BRIDGE;
 652         if (par.target->destroy != NULL)
 653                 par.target->destroy(&par);
 654         module_put(par.target->me);
 655         return 0;
 656 }
 657
 658 static inline int
 659 ebt_check_entry(struct ebt_entry *e, struct net *net,
 660                 const struct ebt_table_info *newinfo,
 661                 const char *name, unsigned int *cnt,
 662                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 663 {
 664         struct ebt_entry_target *t;
 665         struct xt_target *target;
 666         unsigned int i, j, hook = 0, hookmask = 0;
 667         size_t gap;
 668         int ret;
 669         struct xt_mtchk_param mtpar;
 670         struct xt_tgchk_param tgpar;
 671
 672         /* don't mess with the struct ebt_entries */
 673         if (e->bitmask == 0)
 674                 return 0;
 675
 676         if (e->bitmask & ~EBT_F_MASK) {
 677                 BUGPRINT("Unknown flag for bitmask\n");
 678                 return -EINVAL;
 679         }
 680         if (e->invflags & ~EBT_INV_MASK) {
 681                 BUGPRINT("Unknown flag for inv bitmask\n");
 682                 return -EINVAL;
 683         }
 684         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 685                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 686                 return -EINVAL;
 687         }
 688         /* what hook do we belong to? */
 689         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 690                 if (!newinfo->hook_entry[i])
 691                         continue;
 692                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 693                         hook = i;
 694                 else
 695                         break;
 696         }
 697         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 698          * a base chain
 699          */
 700         if (i < NF_BR_NUMHOOKS)
 701                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 702         else {
 703                 for (i = 0; i < udc_cnt; i++)
 704                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 705                                 break;
 706                 if (i == 0)
 707                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 708                 else
 709                         hookmask = cl_s[i - 1].hookmask;
 710         }
 711         i = 0;
 712
 713         memset(&mtpar, 0, sizeof(mtpar));
 714         memset(&tgpar, 0, sizeof(tgpar));
 715         mtpar.net       = tgpar.net       = net;
 716         mtpar.table     = tgpar.table     = name;
 717         mtpar.entryinfo = tgpar.entryinfo = e;
 718         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 719         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 720         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 721         if (ret != 0)
 722                 goto cleanup_matches;
 723         j = 0;
 724         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 725         if (ret != 0)
 726                 goto cleanup_watchers;
 727         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 728         gap = e->next_offset - e->target_offset;
 729
 730         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 731         if (IS_ERR(target)) {
 732                 ret = PTR_ERR(target);
 733                 goto cleanup_watchers;
 734         }
 735
 736         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 737         if (target->family != NFPROTO_BRIDGE) {
 738                 module_put(target->me);
 739                 ret = -ENOENT;
 740                 goto cleanup_watchers;
 741         }
 742
 743         t->u.target = target;
 744         if (t->u.target == &ebt_standard_target) {
 745                 if (gap < sizeof(struct ebt_standard_target)) {
 746                         BUGPRINT("Standard target size too big\n");
 747                         ret = -EFAULT;
 748                         goto cleanup_watchers;
 749                 }
 750                 if (((struct ebt_standard_target *)t)->verdict <
 751                    -NUM_STANDARD_TARGETS) {
 752                         BUGPRINT("Invalid standard target\n");
 753                         ret = -EFAULT;
 754                         goto cleanup_watchers;
 755                 }
 756         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 757                 module_put(t->u.target->me);
 758                 ret = -EFAULT;
 759                 goto cleanup_watchers;
 760         }
 761
 762         tgpar.target   = target;
 763         tgpar.targinfo = t->data;
 764         ret = xt_check_target(&tgpar, t->target_size,
 765               e->ethproto, e->invflags & EBT_IPROTO);
 766         if (ret < 0) {
 767                 module_put(target->me);
 768                 goto cleanup_watchers;
 769         }
 770         (*cnt)++;
 771         return 0;
 772 cleanup_watchers:
 773         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 774 cleanup_matches:
 775         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 776         return ret;
 777 }
 778
 779 /* checks for loops and sets the hook mask for udc
 780  * the hook mask for udc tells us from which base chains the udc can be
 781  * accessed. This mask is a parameter to the check() functions of the extensions
 782  */
 783 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 784                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 785 {
 786         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 787         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 788         const struct ebt_entry_target *t;
 789
 790         while (pos < nentries || chain_nr != -1) {
 791                 /* end of udc, go back one 'recursion' step */
 792                 if (pos == nentries) {
 793                         /* put back values of the time when this chain was called */
 794                         e = cl_s[chain_nr].cs.e;
 795                         if (cl_s[chain_nr].from != -1)
 796                                 nentries =
 797                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 798                         else
 799                                 nentries = chain->nentries;
 800                         pos = cl_s[chain_nr].cs.n;
 801                         /* make sure we won't see a loop that isn't one */
 802                         cl_s[chain_nr].cs.n = 0;
 803                         chain_nr = cl_s[chain_nr].from;
 804                         if (pos == nentries)
 805                                 continue;
 806                 }
 807                 t = (struct ebt_entry_target *)
 808                    (((char *)e) + e->target_offset);
 809                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 810                         goto letscontinue;
 811                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 812                    e->next_offset) {
 813                         BUGPRINT("Standard target size too big\n");
 814                         return -1;
 815                 }
 816                 verdict = ((struct ebt_standard_target *)t)->verdict;
 817                 if (verdict >= 0) { /* jump to another chain */
 818                         struct ebt_entries *hlp2 =
 819                            (struct ebt_entries *)(base + verdict);
 820                         for (i = 0; i < udc_cnt; i++)
 821                                 if (hlp2 == cl_s[i].cs.chaininfo)
 822                                         break;
 823                         /* bad destination or loop */
 824                         if (i == udc_cnt) {
 825                                 BUGPRINT("bad destination\n");
 826                                 return -1;
 827                         }
 828                         if (cl_s[i].cs.n) {
 829                                 BUGPRINT("loop\n");
 830                                 return -1;
 831                         }
 832                         if (cl_s[i].hookmask & (1 << hooknr))
 833                                 goto letscontinue;
 834                         /* this can't be 0, so the loop test is correct */
 835                         cl_s[i].cs.n = pos + 1;
 836                         pos = 0;
 837                         cl_s[i].cs.e = ebt_next_entry(e);
 838                         e = (struct ebt_entry *)(hlp2->data);
 839                         nentries = hlp2->nentries;
 840                         cl_s[i].from = chain_nr;
 841                         chain_nr = i;
 842                         /* this udc is accessible from the base chain for hooknr */
 843                         cl_s[i].hookmask |= (1 << hooknr);
 844                         continue;
 845                 }
 846 letscontinue:
 847                 e = ebt_next_entry(e);
 848                 pos++;
 849         }
 850         return 0;
 851 }
 852
 853 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 854 static int translate_table(struct net *net, const char *name,
 855                            struct ebt_table_info *newinfo)
 856 {
 857         unsigned int i, j, k, udc_cnt;
 858         int ret;
 859         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 860
 861         i = 0;
 862         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 863                 i++;
 864         if (i == NF_BR_NUMHOOKS) {
 865                 BUGPRINT("No valid hooks specified\n");
 866                 return -EINVAL;
 867         }
 868         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 869                 BUGPRINT("Chains don't start at beginning\n");
 870                 return -EINVAL;
 871         }
 872         /* make sure chains are ordered after each other in same order
 873          * as their corresponding hooks
 874          */
 875         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 876                 if (!newinfo->hook_entry[j])
 877                         continue;
 878                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 879                         BUGPRINT("Hook order must be followed\n");
 880                         return -EINVAL;
 881                 }
 882                 i = j;
 883         }
 884
 885         /* do some early checkings and initialize some things */
 886         i = 0; /* holds the expected nr. of entries for the chain */
 887         j = 0; /* holds the up to now counted entries for the chain */
 888         k = 0; /* holds the total nr. of entries, should equal
 889                 * newinfo->nentries afterwards
 890                 */
 891         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 892         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 893            ebt_check_entry_size_and_hooks, newinfo,
 894            &i, &j, &k, &udc_cnt);
 895
 896         if (ret != 0)
 897                 return ret;
 898
 899         if (i != j) {
 900                 BUGPRINT("nentries does not equal the nr of entries in the "
 901                          "(last) chain\n");
 902                 return -EINVAL;
 903         }
 904         if (k != newinfo->nentries) {
 905                 BUGPRINT("Total nentries is wrong\n");
 906                 return -EINVAL;
 907         }
 908
 909         /* get the location of the udc, put them in an array
 910          * while we're at it, allocate the chainstack
 911          */
 912         if (udc_cnt) {
 913                 /* this will get free'd in do_replace()/ebt_register_table()
 914                  * if an error occurs
 915                  */
 916                 newinfo->chainstack =
 917                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 918                 if (!newinfo->chainstack)
 919                         return -ENOMEM;
 920                 for_each_possible_cpu(i) {
 921                         newinfo->chainstack[i] =
 922                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 923                         if (!newinfo->chainstack[i]) {
 924                                 while (i)
 925                                         vfree(newinfo->chainstack[--i]);
 926                                 vfree(newinfo->chainstack);
 927                                 newinfo->chainstack = NULL;
 928                                 return -ENOMEM;
 929                         }
 930                 }
 931
 932                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 933                 if (!cl_s)
 934                         return -ENOMEM;
 935                 i = 0; /* the i'th udc */
 936                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 937                    ebt_get_udc_positions, newinfo, &i, cl_s);
 938                 /* sanity check */
 939                 if (i != udc_cnt) {
 940                         BUGPRINT("i != udc_cnt\n");
 941                         vfree(cl_s);
 942                         return -EFAULT;
 943                 }
 944         }
 945
 946         /* Check for loops */
 947         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 948                 if (newinfo->hook_entry[i])
 949                         if (check_chainloops(newinfo->hook_entry[i],
 950                            cl_s, udc_cnt, i, newinfo->entries)) {
 951                                 vfree(cl_s);
 952                                 return -EINVAL;
 953                         }
 954
 955         /* we now know the following (along with E=mc²):
 956          *  - the nr of entries in each chain is right
 957          *  - the size of the allocated space is right
 958          *  - all valid hooks have a corresponding chain
 959          *  - there are no loops
 960          *  - wrong data can still be on the level of a single entry
 961          *  - could be there are jumps to places that are not the
 962          *    beginning of a chain. This can only occur in chains that
 963          *    are not accessible from any base chains, so we don't care.
 964          */
 965
 966         /* used to know what we need to clean up if something goes wrong */
 967         i = 0;
 968         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 969            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 970         if (ret != 0) {
 971                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 972                                   ebt_cleanup_entry, net, &i);
 973         }
 974         vfree(cl_s);
 975         return ret;
 976 }
 977
 978 /* called under write_lock */
 979 static void get_counters(const struct ebt_counter *oldcounters,
 980                          struct ebt_counter *counters, unsigned int nentries)
 981 {
 982         int i, cpu;
 983         struct ebt_counter *counter_base;
 984
 985         /* counters of cpu 0 */
 986         memcpy(counters, oldcounters,
 987                sizeof(struct ebt_counter) * nentries);
 988
 989         /* add other counters to those of cpu 0 */
 990         for_each_possible_cpu(cpu) {
 991                 if (cpu == 0)
 992                         continue;
 993                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 994                 for (i = 0; i < nentries; i++) {
 995                         counters[i].pcnt += counter_base[i].pcnt;
 996                         counters[i].bcnt += counter_base[i].bcnt;
 997                 }
 998         }
 999 }
1000
1001 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1002                               struct ebt_table_info *newinfo)
1003 {
1004         int ret, i;
1005         struct ebt_counter *counterstmp = NULL;
1006         /* used to be able to unlock earlier */
1007         struct ebt_table_info *table;
1008         struct ebt_table *t;
1009
1010         /* the user wants counters back
1011          * the check on the size is done later, when we have the lock
1012          */
1013         if (repl->num_counters) {
1014                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1015                 counterstmp = vmalloc(size);
1016                 if (!counterstmp)
1017                         return -ENOMEM;
1018         }
1019
1020         newinfo->chainstack = NULL;
1021         ret = ebt_verify_pointers(repl, newinfo);
1022         if (ret != 0)
1023                 goto free_counterstmp;
1024
1025         ret = translate_table(net, repl->name, newinfo);
1026
1027         if (ret != 0)
1028                 goto free_counterstmp;
1029
1030         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1031         if (!t) {
1032                 ret = -ENOENT;
1033                 goto free_iterate;
1034         }
1035
1036         /* the table doesn't like it */
1037         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1038                 goto free_unlock;
1039
1040         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1041                 BUGPRINT("Wrong nr. of counters requested\n");
1042                 ret = -EINVAL;
1043                 goto free_unlock;
1044         }
1045
1046         /* we have the mutex lock, so no danger in reading this pointer */
1047         table = t->private;
1048         /* make sure the table can only be rmmod'ed if it contains no rules */
1049         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1050                 ret = -ENOENT;
1051                 goto free_unlock;
1052         } else if (table->nentries && !newinfo->nentries)
1053                 module_put(t->me);
1054         /* we need an atomic snapshot of the counters */
1055         write_lock_bh(&t->lock);
1056         if (repl->num_counters)
1057                 get_counters(t->private->counters, counterstmp,
1058                    t->private->nentries);
1059
1060         t->private = newinfo;
1061         write_unlock_bh(&t->lock);
1062         mutex_unlock(&ebt_mutex);
1063         /* so, a user can change the chains while having messed up her counter
1064          * allocation. Only reason why this is done is because this way the lock
1065          * is held only once, while this doesn't bring the kernel into a
1066          * dangerous state.
1067          */
1068         if (repl->num_counters &&
1069            copy_to_user(repl->counters, counterstmp,
1070            repl->num_counters * sizeof(struct ebt_counter))) {
1071                 /* Silent error, can't fail, new table is already in place */
1072                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1073         }
1074
1075         /* decrease module count and free resources */
1076         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1077                           ebt_cleanup_entry, net, NULL);
1078
1079         vfree(table->entries);
1080         if (table->chainstack) {
1081                 for_each_possible_cpu(i)
1082                         vfree(table->chainstack[i]);
1083                 vfree(table->chainstack);
1084         }
1085         vfree(table);
1086
1087         vfree(counterstmp);
1088
1089 #ifdef CONFIG_AUDIT
1090         if (audit_enabled) {
1091                 struct audit_buffer *ab;
1092
1093                 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1094                                      AUDIT_NETFILTER_CFG);
1095                 if (ab) {
1096                         audit_log_format(ab, "table=%s family=%u entries=%u",
1097                                          repl->name, AF_BRIDGE, repl->nentries);
1098                         audit_log_end(ab);
1099                 }
1100         }
1101 #endif
1102         return ret;
1103
1104 free_unlock:
1105         mutex_unlock(&ebt_mutex);
1106 free_iterate:
1107         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1108                           ebt_cleanup_entry, net, NULL);
1109 free_counterstmp:
1110         vfree(counterstmp);
1111         /* can be initialized in translate_table() */
1112         if (newinfo->chainstack) {
1113                 for_each_possible_cpu(i)
1114                         vfree(newinfo->chainstack[i]);
1115                 vfree(newinfo->chainstack);
1116         }
1117         return ret;
1118 }
1119
1120 /* replace the table */
1121 static int do_replace(struct net *net, const void __user *user,
1122                       unsigned int len)
1123 {
1124         int ret, countersize;
1125         struct ebt_table_info *newinfo;
1126         struct ebt_replace tmp;
1127
1128         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1129                 return -EFAULT;
1130
1131         if (len != sizeof(tmp) + tmp.entries_size) {
1132                 BUGPRINT("Wrong len argument\n");
1133                 return -EINVAL;
1134         }
1135
1136         if (tmp.entries_size == 0) {
1137                 BUGPRINT("Entries_size never zero\n");
1138                 return -EINVAL;
1139         }
1140         /* overflow check */
1141         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1142                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1143                 return -ENOMEM;
1144         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1145                 return -ENOMEM;
1146
1147         tmp.name[sizeof(tmp.name) - 1] = 0;
1148
1149         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1150         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT,
1151                             PAGE_KERNEL);
1152         if (!newinfo)
1153                 return -ENOMEM;
1154
1155         if (countersize)
1156                 memset(newinfo->counters, 0, countersize);
1157
1158         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT,
1159                                      PAGE_KERNEL);
1160         if (!newinfo->entries) {
1161                 ret = -ENOMEM;
1162                 goto free_newinfo;
1163         }
1164         if (copy_from_user(
1165            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1166                 BUGPRINT("Couldn't copy entries from userspace\n");
1167                 ret = -EFAULT;
1168                 goto free_entries;
1169         }
1170
1171         ret = do_replace_finish(net, &tmp, newinfo);
1172         if (ret == 0)
1173                 return ret;
1174 free_entries:
1175         vfree(newinfo->entries);
1176 free_newinfo:
1177         vfree(newinfo);
1178         return ret;
1179 }
1180
1181 struct ebt_table *
1182 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1183 {
1184         struct ebt_table_info *newinfo;
1185         struct ebt_table *t, *table;
1186         struct ebt_replace_kernel *repl;
1187         int ret, i, countersize;
1188         void *p;
1189
1190         if (input_table == NULL || (repl = input_table->table) == NULL ||
1191             repl->entries == NULL || repl->entries_size == 0 ||
1192             repl->counters != NULL || input_table->private != NULL) {
1193                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1194                 return ERR_PTR(-EINVAL);
1195         }
1196
1197         /* Don't add one table to multiple lists. */
1198         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1199         if (!table) {
1200                 ret = -ENOMEM;
1201                 goto out;
1202         }
1203
1204         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1205         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1206         ret = -ENOMEM;
1207         if (!newinfo)
1208                 goto free_table;
1209
1210         p = vmalloc(repl->entries_size);
1211         if (!p)
1212                 goto free_newinfo;
1213
1214         memcpy(p, repl->entries, repl->entries_size);
1215         newinfo->entries = p;
1216
1217         newinfo->entries_size = repl->entries_size;
1218         newinfo->nentries = repl->nentries;
1219
1220         if (countersize)
1221                 memset(newinfo->counters, 0, countersize);
1222
1223         /* fill in newinfo and parse the entries */
1224         newinfo->chainstack = NULL;
1225         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1226                 if ((repl->valid_hooks & (1 << i)) == 0)
1227                         newinfo->hook_entry[i] = NULL;
1228                 else
1229                         newinfo->hook_entry[i] = p +
1230                                 ((char *)repl->hook_entry[i] - repl->entries);
1231         }
1232         ret = translate_table(net, repl->name, newinfo);
1233         if (ret != 0) {
1234                 BUGPRINT("Translate_table failed\n");
1235                 goto free_chainstack;
1236         }
1237
1238         if (table->check && table->check(newinfo, table->valid_hooks)) {
1239                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1240                 ret = -EINVAL;
1241                 goto free_chainstack;
1242         }
1243
1244         table->private = newinfo;
1245         rwlock_init(&table->lock);
1246         mutex_lock(&ebt_mutex);
1247         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1248                 if (strcmp(t->name, table->name) == 0) {
1249                         ret = -EEXIST;
1250                         BUGPRINT("Table name already exists\n");
1251                         goto free_unlock;
1252                 }
1253         }
1254
1255         /* Hold a reference count if the chains aren't empty */
1256         if (newinfo->nentries && !try_module_get(table->me)) {
1257                 ret = -ENOENT;
1258                 goto free_unlock;
1259         }
1260         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1261         mutex_unlock(&ebt_mutex);
1262         return table;
1263 free_unlock:
1264         mutex_unlock(&ebt_mutex);
1265 free_chainstack:
1266         if (newinfo->chainstack) {
1267                 for_each_possible_cpu(i)
1268                         vfree(newinfo->chainstack[i]);
1269                 vfree(newinfo->chainstack);
1270         }
1271         vfree(newinfo->entries);
1272 free_newinfo:
1273         vfree(newinfo);
1274 free_table:
1275         kfree(table);
1276 out:
1277         return ERR_PTR(ret);
1278 }
1279
1280 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1281 {
1282         int i;
1283
1284         if (!table) {
1285                 BUGPRINT("Request to unregister NULL table!!!\n");
1286                 return;
1287         }
1288         mutex_lock(&ebt_mutex);
1289         list_del(&table->list);
1290         mutex_unlock(&ebt_mutex);
1291         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1292                           ebt_cleanup_entry, net, NULL);
1293         if (table->private->nentries)
1294                 module_put(table->me);
1295         vfree(table->private->entries);
1296         if (table->private->chainstack) {
1297                 for_each_possible_cpu(i)
1298                         vfree(table->private->chainstack[i]);
1299                 vfree(table->private->chainstack);
1300         }
1301         vfree(table->private);
1302         kfree(table);
1303 }
1304
1305 /* userspace just supplied us with counters */
1306 static int do_update_counters(struct net *net, const char *name,
1307                                 struct ebt_counter __user *counters,
1308                                 unsigned int num_counters,
1309                                 const void __user *user, unsigned int len)
1310 {
1311         int i, ret;
1312         struct ebt_counter *tmp;
1313         struct ebt_table *t;
1314
1315         if (num_counters == 0)
1316                 return -EINVAL;
1317
1318         tmp = vmalloc(num_counters * sizeof(*tmp));
1319         if (!tmp)
1320                 return -ENOMEM;
1321
1322         t = find_table_lock(net, name, &ret, &ebt_mutex);
1323         if (!t)
1324                 goto free_tmp;
1325
1326         if (num_counters != t->private->nentries) {
1327                 BUGPRINT("Wrong nr of counters\n");
1328                 ret = -EINVAL;
1329                 goto unlock_mutex;
1330         }
1331
1332         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1333                 ret = -EFAULT;
1334                 goto unlock_mutex;
1335         }
1336
1337         /* we want an atomic add of the counters */
1338         write_lock_bh(&t->lock);
1339
1340         /* we add to the counters of the first cpu */
1341         for (i = 0; i < num_counters; i++) {
1342                 t->private->counters[i].pcnt += tmp[i].pcnt;
1343                 t->private->counters[i].bcnt += tmp[i].bcnt;
1344         }
1345
1346         write_unlock_bh(&t->lock);
1347         ret = 0;
1348 unlock_mutex:
1349         mutex_unlock(&ebt_mutex);
1350 free_tmp:
1351         vfree(tmp);
1352         return ret;
1353 }
1354
1355 static int update_counters(struct net *net, const void __user *user,
1356                             unsigned int len)
1357 {
1358         struct ebt_replace hlp;
1359
1360         if (copy_from_user(&hlp, user, sizeof(hlp)))
1361                 return -EFAULT;
1362
1363         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1364                 return -EINVAL;
1365
1366         return do_update_counters(net, hlp.name, hlp.counters,
1367                                 hlp.num_counters, user, len);
1368 }
1369
1370 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1371                                      const char *base, char __user *ubase)
1372 {
1373         char __user *hlp = ubase + ((char *)m - base);
1374         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1375
1376         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1377          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1378          */
1379         strlcpy(name, m->u.match->name, sizeof(name));
1380         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1381                 return -EFAULT;
1382         return 0;
1383 }
1384
1385 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1386                                        const char *base, char __user *ubase)
1387 {
1388         char __user *hlp = ubase + ((char *)w - base);
1389         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1390
1391         strlcpy(name, w->u.watcher->name, sizeof(name));
1392         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1393                 return -EFAULT;
1394         return 0;
1395 }
1396
1397 static inline int ebt_make_names(struct ebt_entry *e, const char *base,
1398                                  char __user *ubase)
1399 {
1400         int ret;
1401         char __user *hlp;
1402         const struct ebt_entry_target *t;
1403         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1404
1405         if (e->bitmask == 0)
1406                 return 0;
1407
1408         hlp = ubase + (((char *)e + e->target_offset) - base);
1409         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1410
1411         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1412         if (ret != 0)
1413                 return ret;
1414         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1415         if (ret != 0)
1416                 return ret;
1417         strlcpy(name, t->u.target->name, sizeof(name));
1418         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1419                 return -EFAULT;
1420         return 0;
1421 }
1422
1423 static int copy_counters_to_user(struct ebt_table *t,
1424                                  const struct ebt_counter *oldcounters,
1425                                  void __user *user, unsigned int num_counters,
1426                                  unsigned int nentries)
1427 {
1428         struct ebt_counter *counterstmp;
1429         int ret = 0;
1430
1431         /* userspace might not need the counters */
1432         if (num_counters == 0)
1433                 return 0;
1434
1435         if (num_counters != nentries) {
1436                 BUGPRINT("Num_counters wrong\n");
1437                 return -EINVAL;
1438         }
1439
1440         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1441         if (!counterstmp)
1442                 return -ENOMEM;
1443
1444         write_lock_bh(&t->lock);
1445         get_counters(oldcounters, counterstmp, nentries);
1446         write_unlock_bh(&t->lock);
1447
1448         if (copy_to_user(user, counterstmp,
1449            nentries * sizeof(struct ebt_counter)))
1450                 ret = -EFAULT;
1451         vfree(counterstmp);
1452         return ret;
1453 }
1454
1455 /* called with ebt_mutex locked */
1456 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1457                                    const int *len, int cmd)
1458 {
1459         struct ebt_replace tmp;
1460         const struct ebt_counter *oldcounters;
1461         unsigned int entries_size, nentries;
1462         int ret;
1463         char *entries;
1464
1465         if (cmd == EBT_SO_GET_ENTRIES) {
1466                 entries_size = t->private->entries_size;
1467                 nentries = t->private->nentries;
1468                 entries = t->private->entries;
1469                 oldcounters = t->private->counters;
1470         } else {
1471                 entries_size = t->table->entries_size;
1472                 nentries = t->table->nentries;
1473                 entries = t->table->entries;
1474                 oldcounters = t->table->counters;
1475         }
1476
1477         if (copy_from_user(&tmp, user, sizeof(tmp)))
1478                 return -EFAULT;
1479
1480         if (*len != sizeof(struct ebt_replace) + entries_size +
1481            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1482                 return -EINVAL;
1483
1484         if (tmp.nentries != nentries) {
1485                 BUGPRINT("Nentries wrong\n");
1486                 return -EINVAL;
1487         }
1488
1489         if (tmp.entries_size != entries_size) {
1490                 BUGPRINT("Wrong size\n");
1491                 return -EINVAL;
1492         }
1493
1494         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1495                                         tmp.num_counters, nentries);
1496         if (ret)
1497                 return ret;
1498
1499         if (copy_to_user(tmp.entries, entries, entries_size)) {
1500                 BUGPRINT("Couldn't copy entries to userspace\n");
1501                 return -EFAULT;
1502         }
1503         /* set the match/watcher/target names right */
1504         return EBT_ENTRY_ITERATE(entries, entries_size,
1505            ebt_make_names, entries, tmp.entries);
1506 }
1507
1508 static int do_ebt_set_ctl(struct sock *sk,
1509         int cmd, void __user *user, unsigned int len)
1510 {
1511         int ret;
1512         struct net *net = sock_net(sk);
1513
1514         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1515                 return -EPERM;
1516
1517         switch (cmd) {
1518         case EBT_SO_SET_ENTRIES:
1519                 ret = do_replace(net, user, len);
1520                 break;
1521         case EBT_SO_SET_COUNTERS:
1522                 ret = update_counters(net, user, len);
1523                 break;
1524         default:
1525                 ret = -EINVAL;
1526         }
1527         return ret;
1528 }
1529
1530 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1531 {
1532         int ret;
1533         struct ebt_replace tmp;
1534         struct ebt_table *t;
1535         struct net *net = sock_net(sk);
1536
1537         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1538                 return -EPERM;
1539
1540         if (copy_from_user(&tmp, user, sizeof(tmp)))
1541                 return -EFAULT;
1542
1543         tmp.name[sizeof(tmp.name) - 1] = '\0';
1544
1545         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1546         if (!t)
1547                 return ret;
1548
1549         switch (cmd) {
1550         case EBT_SO_GET_INFO:
1551         case EBT_SO_GET_INIT_INFO:
1552                 if (*len != sizeof(struct ebt_replace)) {
1553                         ret = -EINVAL;
1554                         mutex_unlock(&ebt_mutex);
1555                         break;
1556                 }
1557                 if (cmd == EBT_SO_GET_INFO) {
1558                         tmp.nentries = t->private->nentries;
1559                         tmp.entries_size = t->private->entries_size;
1560                         tmp.valid_hooks = t->valid_hooks;
1561                 } else {
1562                         tmp.nentries = t->table->nentries;
1563                         tmp.entries_size = t->table->entries_size;
1564                         tmp.valid_hooks = t->table->valid_hooks;
1565                 }
1566                 mutex_unlock(&ebt_mutex);
1567                 if (copy_to_user(user, &tmp, *len) != 0) {
1568                         BUGPRINT("c2u Didn't work\n");
1569                         ret = -EFAULT;
1570                         break;
1571                 }
1572                 ret = 0;
1573                 break;
1574
1575         case EBT_SO_GET_ENTRIES:
1576         case EBT_SO_GET_INIT_ENTRIES:
1577                 ret = copy_everything_to_user(t, user, len, cmd);
1578                 mutex_unlock(&ebt_mutex);
1579                 break;
1580
1581         default:
1582                 mutex_unlock(&ebt_mutex);
1583                 ret = -EINVAL;
1584         }
1585
1586         return ret;
1587 }
1588
1589 #ifdef CONFIG_COMPAT
1590 /* 32 bit-userspace compatibility definitions. */
1591 struct compat_ebt_replace {
1592         char name[EBT_TABLE_MAXNAMELEN];
1593         compat_uint_t valid_hooks;
1594         compat_uint_t nentries;
1595         compat_uint_t entries_size;
1596         /* start of the chains */
1597         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1598         /* nr of counters userspace expects back */
1599         compat_uint_t num_counters;
1600         /* where the kernel will put the old counters. */
1601         compat_uptr_t counters;
1602         compat_uptr_t entries;
1603 };
1604
1605 /* struct ebt_entry_match, _target and _watcher have same layout */
1606 struct compat_ebt_entry_mwt {
1607         union {
1608                 char name[EBT_FUNCTION_MAXNAMELEN];
1609                 compat_uptr_t ptr;
1610         } u;
1611         compat_uint_t match_size;
1612         compat_uint_t data[0];
1613 };
1614
1615 /* account for possible padding between match_size and ->data */
1616 static int ebt_compat_entry_padsize(void)
1617 {
1618         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1619                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1620         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1621                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1622 }
1623
1624 static int ebt_compat_match_offset(const struct xt_match *match,
1625                                    unsigned int userlen)
1626 {
1627         /* ebt_among needs special handling. The kernel .matchsize is
1628          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1629          * value is expected.
1630          * Example: userspace sends 4500, ebt_among.c wants 4504.
1631          */
1632         if (unlikely(match->matchsize == -1))
1633                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1634         return xt_compat_match_offset(match);
1635 }
1636
1637 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1638                                 unsigned int *size)
1639 {
1640         const struct xt_match *match = m->u.match;
1641         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1642         int off = ebt_compat_match_offset(match, m->match_size);
1643         compat_uint_t msize = m->match_size - off;
1644
1645         if (WARN_ON(off >= m->match_size))
1646                 return -EINVAL;
1647
1648         if (copy_to_user(cm->u.name, match->name,
1649             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1650                 return -EFAULT;
1651
1652         if (match->compat_to_user) {
1653                 if (match->compat_to_user(cm->data, m->data))
1654                         return -EFAULT;
1655         } else if (copy_to_user(cm->data, m->data, msize))
1656                         return -EFAULT;
1657
1658         *size -= ebt_compat_entry_padsize() + off;
1659         *dstptr = cm->data;
1660         *dstptr += msize;
1661         return 0;
1662 }
1663
1664 static int compat_target_to_user(struct ebt_entry_target *t,
1665                                  void __user **dstptr,
1666                                  unsigned int *size)
1667 {
1668         const struct xt_target *target = t->u.target;
1669         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1670         int off = xt_compat_target_offset(target);
1671         compat_uint_t tsize = t->target_size - off;
1672
1673         if (WARN_ON(off >= t->target_size))
1674                 return -EINVAL;
1675
1676         if (copy_to_user(cm->u.name, target->name,
1677             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1678                 return -EFAULT;
1679
1680         if (target->compat_to_user) {
1681                 if (target->compat_to_user(cm->data, t->data))
1682                         return -EFAULT;
1683         } else if (copy_to_user(cm->data, t->data, tsize))
1684                 return -EFAULT;
1685
1686         *size -= ebt_compat_entry_padsize() + off;
1687         *dstptr = cm->data;
1688         *dstptr += tsize;
1689         return 0;
1690 }
1691
1692 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1693                                   void __user **dstptr,
1694                                   unsigned int *size)
1695 {
1696         return compat_target_to_user((struct ebt_entry_target *)w,
1697                                                         dstptr, size);
1698 }
1699
1700 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1701                                 unsigned int *size)
1702 {
1703         struct ebt_entry_target *t;
1704         struct ebt_entry __user *ce;
1705         u32 watchers_offset, target_offset, next_offset;
1706         compat_uint_t origsize;
1707         int ret;
1708
1709         if (e->bitmask == 0) {
1710                 if (*size < sizeof(struct ebt_entries))
1711                         return -EINVAL;
1712                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1713                         return -EFAULT;
1714
1715                 *dstptr += sizeof(struct ebt_entries);
1716                 *size -= sizeof(struct ebt_entries);
1717                 return 0;
1718         }
1719
1720         if (*size < sizeof(*ce))
1721                 return -EINVAL;
1722
1723         ce = (struct ebt_entry __user *)*dstptr;
1724         if (copy_to_user(ce, e, sizeof(*ce)))
1725                 return -EFAULT;
1726
1727         origsize = *size;
1728         *dstptr += sizeof(*ce);
1729
1730         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1731         if (ret)
1732                 return ret;
1733         watchers_offset = e->watchers_offset - (origsize - *size);
1734
1735         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1736         if (ret)
1737                 return ret;
1738         target_offset = e->target_offset - (origsize - *size);
1739
1740         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1741
1742         ret = compat_target_to_user(t, dstptr, size);
1743         if (ret)
1744                 return ret;
1745         next_offset = e->next_offset - (origsize - *size);
1746
1747         if (put_user(watchers_offset, &ce->watchers_offset) ||
1748             put_user(target_offset, &ce->target_offset) ||
1749             put_user(next_offset, &ce->next_offset))
1750                 return -EFAULT;
1751
1752         *size -= sizeof(*ce);
1753         return 0;
1754 }
1755
1756 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1757 {
1758         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1759         *off += ebt_compat_entry_padsize();
1760         return 0;
1761 }
1762
1763 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1764 {
1765         *off += xt_compat_target_offset(w->u.watcher);
1766         *off += ebt_compat_entry_padsize();
1767         return 0;
1768 }
1769
1770 static int compat_calc_entry(const struct ebt_entry *e,
1771                              const struct ebt_table_info *info,
1772                              const void *base,
1773                              struct compat_ebt_replace *newinfo)
1774 {
1775         const struct ebt_entry_target *t;
1776         unsigned int entry_offset;
1777         int off, ret, i;
1778
1779         if (e->bitmask == 0)
1780                 return 0;
1781
1782         off = 0;
1783         entry_offset = (void *)e - base;
1784
1785         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1786         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1787
1788         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1789
1790         off += xt_compat_target_offset(t->u.target);
1791         off += ebt_compat_entry_padsize();
1792
1793         newinfo->entries_size -= off;
1794
1795         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1796         if (ret)
1797                 return ret;
1798
1799         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1800                 const void *hookptr = info->hook_entry[i];
1801                 if (info->hook_entry[i] &&
1802                     (e < (struct ebt_entry *)(base - hookptr))) {
1803                         newinfo->hook_entry[i] -= off;
1804                         pr_debug("0x%08X -> 0x%08X\n",
1805                                         newinfo->hook_entry[i] + off,
1806                                         newinfo->hook_entry[i]);
1807                 }
1808         }
1809
1810         return 0;
1811 }
1812
1813
1814 static int compat_table_info(const struct ebt_table_info *info,
1815                              struct compat_ebt_replace *newinfo)
1816 {
1817         unsigned int size = info->entries_size;
1818         const void *entries = info->entries;
1819
1820         newinfo->entries_size = size;
1821
1822         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1823         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1824                                                         entries, newinfo);
1825 }
1826
1827 static int compat_copy_everything_to_user(struct ebt_table *t,
1828                                           void __user *user, int *len, int cmd)
1829 {
1830         struct compat_ebt_replace repl, tmp;
1831         struct ebt_counter *oldcounters;
1832         struct ebt_table_info tinfo;
1833         int ret;
1834         void __user *pos;
1835
1836         memset(&tinfo, 0, sizeof(tinfo));
1837
1838         if (cmd == EBT_SO_GET_ENTRIES) {
1839                 tinfo.entries_size = t->private->entries_size;
1840                 tinfo.nentries = t->private->nentries;
1841                 tinfo.entries = t->private->entries;
1842                 oldcounters = t->private->counters;
1843         } else {
1844                 tinfo.entries_size = t->table->entries_size;
1845                 tinfo.nentries = t->table->nentries;
1846                 tinfo.entries = t->table->entries;
1847                 oldcounters = t->table->counters;
1848         }
1849
1850         if (copy_from_user(&tmp, user, sizeof(tmp)))
1851                 return -EFAULT;
1852
1853         if (tmp.nentries != tinfo.nentries ||
1854            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1855                 return -EINVAL;
1856
1857         memcpy(&repl, &tmp, sizeof(repl));
1858         if (cmd == EBT_SO_GET_ENTRIES)
1859                 ret = compat_table_info(t->private, &repl);
1860         else
1861                 ret = compat_table_info(&tinfo, &repl);
1862         if (ret)
1863                 return ret;
1864
1865         if (*len != sizeof(tmp) + repl.entries_size +
1866            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1867                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1868                                 *len, tinfo.entries_size, repl.entries_size);
1869                 return -EINVAL;
1870         }
1871
1872         /* userspace might not need the counters */
1873         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1874                                         tmp.num_counters, tinfo.nentries);
1875         if (ret)
1876                 return ret;
1877
1878         pos = compat_ptr(tmp.entries);
1879         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1880                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1881 }
1882
1883 struct ebt_entries_buf_state {
1884         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1885         u32 buf_kern_len;       /* total size of kernel buffer */
1886         u32 buf_kern_offset;    /* amount of data copied so far */
1887         u32 buf_user_offset;    /* read position in userspace buffer */
1888 };
1889
1890 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1891 {
1892         state->buf_kern_offset += sz;
1893         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1894 }
1895
1896 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1897                        const void *data, unsigned int sz)
1898 {
1899         if (state->buf_kern_start == NULL)
1900                 goto count_only;
1901
1902         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1903                 return -EINVAL;
1904
1905         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1906
1907  count_only:
1908         state->buf_user_offset += sz;
1909         return ebt_buf_count(state, sz);
1910 }
1911
1912 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1913 {
1914         char *b = state->buf_kern_start;
1915
1916         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1917                 return -EINVAL;
1918
1919         if (b != NULL && sz > 0)
1920                 memset(b + state->buf_kern_offset, 0, sz);
1921         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1922         return ebt_buf_count(state, sz);
1923 }
1924
1925 enum compat_mwt {
1926         EBT_COMPAT_MATCH,
1927         EBT_COMPAT_WATCHER,
1928         EBT_COMPAT_TARGET,
1929 };
1930
1931 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1932                                 enum compat_mwt compat_mwt,
1933                                 struct ebt_entries_buf_state *state,
1934                                 const unsigned char *base)
1935 {
1936         char name[EBT_FUNCTION_MAXNAMELEN];
1937         struct xt_match *match;
1938         struct xt_target *wt;
1939         void *dst = NULL;
1940         int off, pad = 0;
1941         unsigned int size_kern, match_size = mwt->match_size;
1942
1943         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1944                 return -EINVAL;
1945
1946         if (state->buf_kern_start)
1947                 dst = state->buf_kern_start + state->buf_kern_offset;
1948
1949         switch (compat_mwt) {
1950         case EBT_COMPAT_MATCH:
1951                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1952                 if (IS_ERR(match))
1953                         return PTR_ERR(match);
1954
1955                 off = ebt_compat_match_offset(match, match_size);
1956                 if (dst) {
1957                         if (match->compat_from_user)
1958                                 match->compat_from_user(dst, mwt->data);
1959                         else
1960                                 memcpy(dst, mwt->data, match_size);
1961                 }
1962
1963                 size_kern = match->matchsize;
1964                 if (unlikely(size_kern == -1))
1965                         size_kern = match_size;
1966                 module_put(match->me);
1967                 break;
1968         case EBT_COMPAT_WATCHER: /* fallthrough */
1969         case EBT_COMPAT_TARGET:
1970                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1971                 if (IS_ERR(wt))
1972                         return PTR_ERR(wt);
1973                 off = xt_compat_target_offset(wt);
1974
1975                 if (dst) {
1976                         if (wt->compat_from_user)
1977                                 wt->compat_from_user(dst, mwt->data);
1978                         else
1979                                 memcpy(dst, mwt->data, match_size);
1980                 }
1981
1982                 size_kern = wt->targetsize;
1983                 module_put(wt->me);
1984                 break;
1985
1986         default:
1987                 return -EINVAL;
1988         }
1989
1990         state->buf_kern_offset += match_size + off;
1991         state->buf_user_offset += match_size;
1992         pad = XT_ALIGN(size_kern) - size_kern;
1993
1994         if (pad > 0 && dst) {
1995                 if (WARN_ON(state->buf_kern_len <= pad))
1996                         return -EINVAL;
1997                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
1998                         return -EINVAL;
1999                 memset(dst + size_kern, 0, pad);
2000         }
2001         return off + match_size;
2002 }
2003
2004 /* return size of all matches, watchers or target, including necessary
2005  * alignment and padding.
2006  */
2007 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2008                         unsigned int size_left, enum compat_mwt type,
2009                         struct ebt_entries_buf_state *state, const void *base)
2010 {
2011         const char *buf = (const char *)match32;
2012         int growth = 0;
2013
2014         if (size_left == 0)
2015                 return 0;
2016
2017         do {
2018                 struct ebt_entry_match *match_kern;
2019                 int ret;
2020
2021                 if (size_left < sizeof(*match32))
2022                         return -EINVAL;
2023
2024                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2025                 if (match_kern) {
2026                         char *tmp;
2027                         tmp = state->buf_kern_start + state->buf_kern_offset;
2028                         match_kern = (struct ebt_entry_match *) tmp;
2029                 }
2030                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2031                 if (ret < 0)
2032                         return ret;
2033                 size_left -= sizeof(*match32);
2034
2035                 /* add padding before match->data (if any) */
2036                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2037                 if (ret < 0)
2038                         return ret;
2039
2040                 if (match32->match_size > size_left)
2041                         return -EINVAL;
2042
2043                 size_left -= match32->match_size;
2044
2045                 ret = compat_mtw_from_user(match32, type, state, base);
2046                 if (ret < 0)
2047                         return ret;
2048
2049                 if (WARN_ON(ret < match32->match_size))
2050                         return -EINVAL;
2051                 growth += ret - match32->match_size;
2052                 growth += ebt_compat_entry_padsize();
2053
2054                 buf += sizeof(*match32);
2055                 buf += match32->match_size;
2056
2057                 if (match_kern)
2058                         match_kern->match_size = ret;
2059
2060                 match32 = (struct compat_ebt_entry_mwt *) buf;
2061         } while (size_left);
2062
2063         return growth;
2064 }
2065
2066 /* called for all ebt_entry structures. */
2067 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2068                           unsigned int *total,
2069                           struct ebt_entries_buf_state *state)
2070 {
2071         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2072         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2073         unsigned int offsets[4];
2074         unsigned int *offsets_update = NULL;
2075         int ret;
2076         char *buf_start;
2077
2078         if (*total < sizeof(struct ebt_entries))
2079                 return -EINVAL;
2080
2081         if (!entry->bitmask) {
2082                 *total -= sizeof(struct ebt_entries);
2083                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2084         }
2085         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2086                 return -EINVAL;
2087
2088         startoff = state->buf_user_offset;
2089         /* pull in most part of ebt_entry, it does not need to be changed. */
2090         ret = ebt_buf_add(state, entry,
2091                         offsetof(struct ebt_entry, watchers_offset));
2092         if (ret < 0)
2093                 return ret;
2094
2095         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2096         memcpy(&offsets[1], &entry->watchers_offset,
2097                         sizeof(offsets) - sizeof(offsets[0]));
2098
2099         if (state->buf_kern_start) {
2100                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2101                 offsets_update = (unsigned int *) buf_start;
2102         }
2103         ret = ebt_buf_add(state, &offsets[1],
2104                         sizeof(offsets) - sizeof(offsets[0]));
2105         if (ret < 0)
2106                 return ret;
2107         buf_start = (char *) entry;
2108         /* 0: matches offset, always follows ebt_entry.
2109          * 1: watchers offset, from ebt_entry structure
2110          * 2: target offset, from ebt_entry structure
2111          * 3: next ebt_entry offset, from ebt_entry structure
2112          *
2113          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2114          */
2115         for (i = 0; i < 4 ; ++i) {
2116                 if (offsets[i] > *total)
2117                         return -EINVAL;
2118
2119                 if (i < 3 && offsets[i] == *total)
2120                         return -EINVAL;
2121
2122                 if (i == 0)
2123                         continue;
2124                 if (offsets[i-1] > offsets[i])
2125                         return -EINVAL;
2126         }
2127
2128         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2129                 struct compat_ebt_entry_mwt *match32;
2130                 unsigned int size;
2131                 char *buf = buf_start;
2132
2133                 buf = buf_start + offsets[i];
2134                 if (offsets[i] > offsets[j])
2135                         return -EINVAL;
2136
2137                 match32 = (struct compat_ebt_entry_mwt *) buf;
2138                 size = offsets[j] - offsets[i];
2139                 ret = ebt_size_mwt(match32, size, i, state, base);
2140                 if (ret < 0)
2141                         return ret;
2142                 new_offset += ret;
2143                 if (offsets_update && new_offset) {
2144                         pr_debug("change offset %d to %d\n",
2145                                 offsets_update[i], offsets[j] + new_offset);
2146                         offsets_update[i] = offsets[j] + new_offset;
2147                 }
2148         }
2149
2150         if (state->buf_kern_start == NULL) {
2151                 unsigned int offset = buf_start - (char *) base;
2152
2153                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2154                 if (ret < 0)
2155                         return ret;
2156         }
2157
2158         next_expected_off = state->buf_user_offset - startoff;
2159         if (next_expected_off != entry->next_offset)
2160                 return -EINVAL;
2161
2162         if (*total < entry->next_offset)
2163                 return -EINVAL;
2164         *total -= entry->next_offset;
2165         return 0;
2166 }
2167
2168 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2169  * It might need more memory when copied to a 64 bit kernel in case
2170  * userspace is 32-bit. So, first task: find out how much memory is needed.
2171  *
2172  * Called before validation is performed.
2173  */
2174 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2175                                 struct ebt_entries_buf_state *state)
2176 {
2177         unsigned int size_remaining = size_user;
2178         int ret;
2179
2180         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2181                                         &size_remaining, state);
2182         if (ret < 0)
2183                 return ret;
2184
2185         if (size_remaining)
2186                 return -EINVAL;
2187
2188         return state->buf_kern_offset;
2189 }
2190
2191
2192 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2193                                             void __user *user, unsigned int len)
2194 {
2195         struct compat_ebt_replace tmp;
2196         int i;
2197
2198         if (len < sizeof(tmp))
2199                 return -EINVAL;
2200
2201         if (copy_from_user(&tmp, user, sizeof(tmp)))
2202                 return -EFAULT;
2203
2204         if (len != sizeof(tmp) + tmp.entries_size)
2205                 return -EINVAL;
2206
2207         if (tmp.entries_size == 0)
2208                 return -EINVAL;
2209
2210         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2211                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2212                 return -ENOMEM;
2213         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2214                 return -ENOMEM;
2215
2216         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2217
2218         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2219         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2220                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2221
2222         repl->num_counters = tmp.num_counters;
2223         repl->counters = compat_ptr(tmp.counters);
2224         repl->entries = compat_ptr(tmp.entries);
2225         return 0;
2226 }
2227
2228 static int compat_do_replace(struct net *net, void __user *user,
2229                              unsigned int len)
2230 {
2231         int ret, i, countersize, size64;
2232         struct ebt_table_info *newinfo;
2233         struct ebt_replace tmp;
2234         struct ebt_entries_buf_state state;
2235         void *entries_tmp;
2236
2237         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2238         if (ret) {
2239                 /* try real handler in case userland supplied needed padding */
2240                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2241                         ret = 0;
2242                 return ret;
2243         }
2244
2245         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2246         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2247         if (!newinfo)
2248                 return -ENOMEM;
2249
2250         if (countersize)
2251                 memset(newinfo->counters, 0, countersize);
2252
2253         memset(&state, 0, sizeof(state));
2254
2255         newinfo->entries = vmalloc(tmp.entries_size);
2256         if (!newinfo->entries) {
2257                 ret = -ENOMEM;
2258                 goto free_newinfo;
2259         }
2260         if (copy_from_user(
2261            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2262                 ret = -EFAULT;
2263                 goto free_entries;
2264         }
2265
2266         entries_tmp = newinfo->entries;
2267
2268         xt_compat_lock(NFPROTO_BRIDGE);
2269
2270         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2271         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2272         if (ret < 0)
2273                 goto out_unlock;
2274
2275         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2276                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2277                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2278
2279         size64 = ret;
2280         newinfo->entries = vmalloc(size64);
2281         if (!newinfo->entries) {
2282                 vfree(entries_tmp);
2283                 ret = -ENOMEM;
2284                 goto out_unlock;
2285         }
2286
2287         memset(&state, 0, sizeof(state));
2288         state.buf_kern_start = newinfo->entries;
2289         state.buf_kern_len = size64;
2290
2291         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2292         if (WARN_ON(ret < 0)) {
2293                 vfree(entries_tmp);
2294                 goto out_unlock;
2295         }
2296
2297         vfree(entries_tmp);
2298         tmp.entries_size = size64;
2299
2300         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2301                 char __user *usrptr;
2302                 if (tmp.hook_entry[i]) {
2303                         unsigned int delta;
2304                         usrptr = (char __user *) tmp.hook_entry[i];
2305                         delta = usrptr - tmp.entries;
2306                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2307                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2308                 }
2309         }
2310
2311         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2312         xt_compat_unlock(NFPROTO_BRIDGE);
2313
2314         ret = do_replace_finish(net, &tmp, newinfo);
2315         if (ret == 0)
2316                 return ret;
2317 free_entries:
2318         vfree(newinfo->entries);
2319 free_newinfo:
2320         vfree(newinfo);
2321         return ret;
2322 out_unlock:
2323         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2324         xt_compat_unlock(NFPROTO_BRIDGE);
2325         goto free_entries;
2326 }
2327
2328 static int compat_update_counters(struct net *net, void __user *user,
2329                                   unsigned int len)
2330 {
2331         struct compat_ebt_replace hlp;
2332
2333         if (copy_from_user(&hlp, user, sizeof(hlp)))
2334                 return -EFAULT;
2335
2336         /* try real handler in case userland supplied needed padding */
2337         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2338                 return update_counters(net, user, len);
2339
2340         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2341                                         hlp.num_counters, user, len);
2342 }
2343
2344 static int compat_do_ebt_set_ctl(struct sock *sk,
2345                 int cmd, void __user *user, unsigned int len)
2346 {
2347         int ret;
2348         struct net *net = sock_net(sk);
2349
2350         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2351                 return -EPERM;
2352
2353         switch (cmd) {
2354         case EBT_SO_SET_ENTRIES:
2355                 ret = compat_do_replace(net, user, len);
2356                 break;
2357         case EBT_SO_SET_COUNTERS:
2358                 ret = compat_update_counters(net, user, len);
2359                 break;
2360         default:
2361                 ret = -EINVAL;
2362         }
2363         return ret;
2364 }
2365
2366 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2367                 void __user *user, int *len)
2368 {
2369         int ret;
2370         struct compat_ebt_replace tmp;
2371         struct ebt_table *t;
2372         struct net *net = sock_net(sk);
2373
2374         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2375                 return -EPERM;
2376
2377         /* try real handler in case userland supplied needed padding */
2378         if ((cmd == EBT_SO_GET_INFO ||
2379              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2380                         return do_ebt_get_ctl(sk, cmd, user, len);
2381
2382         if (copy_from_user(&tmp, user, sizeof(tmp)))
2383                 return -EFAULT;
2384
2385         tmp.name[sizeof(tmp.name) - 1] = '\0';
2386
2387         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2388         if (!t)
2389                 return ret;
2390
2391         xt_compat_lock(NFPROTO_BRIDGE);
2392         switch (cmd) {
2393         case EBT_SO_GET_INFO:
2394                 tmp.nentries = t->private->nentries;
2395                 ret = compat_table_info(t->private, &tmp);
2396                 if (ret)
2397                         goto out;
2398                 tmp.valid_hooks = t->valid_hooks;
2399
2400                 if (copy_to_user(user, &tmp, *len) != 0) {
2401                         ret = -EFAULT;
2402                         break;
2403                 }
2404                 ret = 0;
2405                 break;
2406         case EBT_SO_GET_INIT_INFO:
2407                 tmp.nentries = t->table->nentries;
2408                 tmp.entries_size = t->table->entries_size;
2409                 tmp.valid_hooks = t->table->valid_hooks;
2410
2411                 if (copy_to_user(user, &tmp, *len) != 0) {
2412                         ret = -EFAULT;
2413                         break;
2414                 }
2415                 ret = 0;
2416                 break;
2417         case EBT_SO_GET_ENTRIES:
2418         case EBT_SO_GET_INIT_ENTRIES:
2419                 /* try real handler first in case of userland-side padding.
2420                  * in case we are dealing with an 'ordinary' 32 bit binary
2421                  * without 64bit compatibility padding, this will fail right
2422                  * after copy_from_user when the *len argument is validated.
2423                  *
2424                  * the compat_ variant needs to do one pass over the kernel
2425                  * data set to adjust for size differences before it the check.
2426                  */
2427                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2428                         ret = 0;
2429                 else
2430                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2431                 break;
2432         default:
2433                 ret = -EINVAL;
2434         }
2435  out:
2436         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2437         xt_compat_unlock(NFPROTO_BRIDGE);
2438         mutex_unlock(&ebt_mutex);
2439         return ret;
2440 }
2441 #endif
2442
2443 static struct nf_sockopt_ops ebt_sockopts = {
2444         .pf             = PF_INET,
2445         .set_optmin     = EBT_BASE_CTL,
2446         .set_optmax     = EBT_SO_SET_MAX + 1,
2447         .set            = do_ebt_set_ctl,
2448 #ifdef CONFIG_COMPAT
2449         .compat_set     = compat_do_ebt_set_ctl,
2450 #endif
2451         .get_optmin     = EBT_BASE_CTL,
2452         .get_optmax     = EBT_SO_GET_MAX + 1,
2453         .get            = do_ebt_get_ctl,
2454 #ifdef CONFIG_COMPAT
2455         .compat_get     = compat_do_ebt_get_ctl,
2456 #endif
2457         .owner          = THIS_MODULE,
2458 };
2459
2460 static int __init ebtables_init(void)
2461 {
2462         int ret;
2463
2464         ret = xt_register_target(&ebt_standard_target);
2465         if (ret < 0)
2466                 return ret;
2467         ret = nf_register_sockopt(&ebt_sockopts);
2468         if (ret < 0) {
2469                 xt_unregister_target(&ebt_standard_target);
2470                 return ret;
2471         }
2472
2473         printk(KERN_INFO "Ebtables v2.0 registered\n");
2474         return 0;
2475 }
2476
2477 static void __exit ebtables_fini(void)
2478 {
2479         nf_unregister_sockopt(&ebt_sockopts);
2480         xt_unregister_target(&ebt_standard_target);
2481         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2482 }
2483
2484 EXPORT_SYMBOL(ebt_register_table);
2485 EXPORT_SYMBOL(ebt_unregister_table);
2486 EXPORT_SYMBOL(ebt_do_table);
2487 module_init(ebtables_init);
2488 module_exit(ebtables_fini);
2489 MODULE_LICENSE("GPL");