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