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