net/bridge/netfilter/ebtables.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ebtables
   4  *
   5  *  Author:
   6  *  Bart De Schuymer            <bdschuym@pandora.be>
   7  *
   8  *  ebtables.c,v 2.0, July, 2002
   9  *
  10  *  This code is strongly inspired by the iptables code which is
  11  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  12  */
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/kmod.h>
  15 #include <linux/module.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/netfilter/x_tables.h>
  18 #include <linux/netfilter_bridge/ebtables.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/mutex.h>
  21 #include <linux/slab.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/smp.h>
  24 #include <linux/cpumask.h>
  25 #include <linux/audit.h>
  26 #include <net/sock.h>
  27 #include <net/netns/generic.h>
  28 /* needed for logical [in,out]-dev filtering */
  29 #include "../br_private.h"
  30
  31 /* Each cpu has its own set of counters, so there is no need for write_lock in
  32  * the softirq
  33  * For reading or updating the counters, the user context needs to
  34  * get a write_lock
  35  */
  36
  37 /* The size of each set of counters is altered to get cache alignment */
  38 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  39 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  40 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  41                                  COUNTER_OFFSET(n) * cpu))
  42
  43 struct ebt_pernet {
  44         struct list_head tables;
  45 };
  46
  47 struct ebt_template {
  48         struct list_head list;
  49         char name[EBT_TABLE_MAXNAMELEN];
  50         struct module *owner;
  51         /* called when table is needed in the given netns */
  52         int (*table_init)(struct net *net);
  53 };
  54
  55 static unsigned int ebt_pernet_id __read_mostly;
  56 static LIST_HEAD(template_tables);
  57 static DEFINE_MUTEX(ebt_mutex);
  58
  59 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  60 static void ebt_standard_compat_from_user(void *dst, const void *src)
  61 {
  62         int v = *(compat_int_t *)src;
  63
  64         if (v >= 0)
  65                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  66         memcpy(dst, &v, sizeof(v));
  67 }
  68
  69 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  70 {
  71         compat_int_t cv = *(int *)src;
  72
  73         if (cv >= 0)
  74                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  75         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  76 }
  77 #endif
  78
  79
  80 static struct xt_target ebt_standard_target = {
  81         .name       = "standard",
  82         .revision   = 0,
  83         .family     = NFPROTO_BRIDGE,
  84         .targetsize = sizeof(int),
  85 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  86         .compatsize = sizeof(compat_int_t),
  87         .compat_from_user = ebt_standard_compat_from_user,
  88         .compat_to_user =  ebt_standard_compat_to_user,
  89 #endif
  90 };
  91
  92 static inline int
  93 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  94                struct xt_action_param *par)
  95 {
  96         par->target   = w->u.watcher;
  97         par->targinfo = w->data;
  98         w->u.watcher->target(skb, par);
  99         /* watchers don't give a verdict */
 100         return 0;
 101 }
 102
 103 static inline int
 104 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 105              struct xt_action_param *par)
 106 {
 107         par->match     = m->u.match;
 108         par->matchinfo = m->data;
 109         return !m->u.match->match(skb, par);
 110 }
 111
 112 static inline int
 113 ebt_dev_check(const char *entry, const struct net_device *device)
 114 {
 115         int i = 0;
 116         const char *devname;
 117
 118         if (*entry == '\0')
 119                 return 0;
 120         if (!device)
 121                 return 1;
 122         devname = device->name;
 123         /* 1 is the wildcard token */
 124         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 125                 i++;
 126         return devname[i] != entry[i] && entry[i] != 1;
 127 }
 128
 129 /* process standard matches */
 130 static inline int
 131 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 132                 const struct net_device *in, const struct net_device *out)
 133 {
 134         const struct ethhdr *h = eth_hdr(skb);
 135         const struct net_bridge_port *p;
 136         __be16 ethproto;
 137
 138         if (skb_vlan_tag_present(skb))
 139                 ethproto = htons(ETH_P_8021Q);
 140         else
 141                 ethproto = h->h_proto;
 142
 143         if (e->bitmask & EBT_802_3) {
 144                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 145                         return 1;
 146         } else if (!(e->bitmask & EBT_NOPROTO) &&
 147                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 148                 return 1;
 149
 150         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 151                 return 1;
 152         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 153                 return 1;
 154         /* rcu_read_lock()ed by nf_hook_thresh */
 155         if (in && (p = br_port_get_rcu(in)) != NULL &&
 156             NF_INVF(e, EBT_ILOGICALIN,
 157                     ebt_dev_check(e->logical_in, p->br->dev)))
 158                 return 1;
 159         if (out && (p = br_port_get_rcu(out)) != NULL &&
 160             NF_INVF(e, EBT_ILOGICALOUT,
 161                     ebt_dev_check(e->logical_out, p->br->dev)))
 162                 return 1;
 163
 164         if (e->bitmask & EBT_SOURCEMAC) {
 165                 if (NF_INVF(e, EBT_ISOURCE,
 166                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 167                                                      e->sourcemsk)))
 168                         return 1;
 169         }
 170         if (e->bitmask & EBT_DESTMAC) {
 171                 if (NF_INVF(e, EBT_IDEST,
 172                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 173                                                      e->destmsk)))
 174                         return 1;
 175         }
 176         return 0;
 177 }
 178
 179 static inline
 180 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 181 {
 182         return (void *)entry + entry->next_offset;
 183 }
 184
 185 static inline const struct ebt_entry_target *
 186 ebt_get_target_c(const struct ebt_entry *e)
 187 {
 188         return ebt_get_target((struct ebt_entry *)e);
 189 }
 190
 191 /* Do some firewalling */
 192 unsigned int ebt_do_table(struct sk_buff *skb,
 193                           const struct nf_hook_state *state,
 194                           struct ebt_table *table)
 195 {
 196         unsigned int hook = state->hook;
 197         int i, nentries;
 198         struct ebt_entry *point;
 199         struct ebt_counter *counter_base, *cb_base;
 200         const struct ebt_entry_target *t;
 201         int verdict, sp = 0;
 202         struct ebt_chainstack *cs;
 203         struct ebt_entries *chaininfo;
 204         const char *base;
 205         const struct ebt_table_info *private;
 206         struct xt_action_param acpar;
 207
 208         acpar.state   = state;
 209         acpar.hotdrop = false;
 210
 211         read_lock_bh(&table->lock);
 212         private = table->private;
 213         cb_base = COUNTER_BASE(private->counters, private->nentries,
 214            smp_processor_id());
 215         if (private->chainstack)
 216                 cs = private->chainstack[smp_processor_id()];
 217         else
 218                 cs = NULL;
 219         chaininfo = private->hook_entry[hook];
 220         nentries = private->hook_entry[hook]->nentries;
 221         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 222         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 223         /* base for chain jumps */
 224         base = private->entries;
 225         i = 0;
 226         while (i < nentries) {
 227                 if (ebt_basic_match(point, skb, state->in, state->out))
 228                         goto letscontinue;
 229
 230                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 231                         goto letscontinue;
 232                 if (acpar.hotdrop) {
 233                         read_unlock_bh(&table->lock);
 234                         return NF_DROP;
 235                 }
 236
 237                 ADD_COUNTER(*(counter_base + i), skb->len, 1);
 238
 239                 /* these should only watch: not modify, nor tell us
 240                  * what to do with the packet
 241                  */
 242                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 243
 244                 t = ebt_get_target_c(point);
 245                 /* standard target */
 246                 if (!t->u.target->target)
 247                         verdict = ((struct ebt_standard_target *)t)->verdict;
 248                 else {
 249                         acpar.target   = t->u.target;
 250                         acpar.targinfo = t->data;
 251                         verdict = t->u.target->target(skb, &acpar);
 252                 }
 253                 if (verdict == EBT_ACCEPT) {
 254                         read_unlock_bh(&table->lock);
 255                         return NF_ACCEPT;
 256                 }
 257                 if (verdict == EBT_DROP) {
 258                         read_unlock_bh(&table->lock);
 259                         return NF_DROP;
 260                 }
 261                 if (verdict == EBT_RETURN) {
 262 letsreturn:
 263                         if (WARN(sp == 0, "RETURN on base chain")) {
 264                                 /* act like this is EBT_CONTINUE */
 265                                 goto letscontinue;
 266                         }
 267
 268                         sp--;
 269                         /* put all the local variables right */
 270                         i = cs[sp].n;
 271                         chaininfo = cs[sp].chaininfo;
 272                         nentries = chaininfo->nentries;
 273                         point = cs[sp].e;
 274                         counter_base = cb_base +
 275                            chaininfo->counter_offset;
 276                         continue;
 277                 }
 278                 if (verdict == EBT_CONTINUE)
 279                         goto letscontinue;
 280
 281                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 282                         read_unlock_bh(&table->lock);
 283                         return NF_DROP;
 284                 }
 285
 286                 /* jump to a udc */
 287                 cs[sp].n = i + 1;
 288                 cs[sp].chaininfo = chaininfo;
 289                 cs[sp].e = ebt_next_entry(point);
 290                 i = 0;
 291                 chaininfo = (struct ebt_entries *) (base + verdict);
 292
 293                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 294                         read_unlock_bh(&table->lock);
 295                         return NF_DROP;
 296                 }
 297
 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 net *net, const char *name, int *error,
 322                         struct mutex *mutex)
 323 {
 324         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
 325         struct ebt_template *tmpl;
 326         struct ebt_table *table;
 327
 328         mutex_lock(mutex);
 329         list_for_each_entry(table, &ebt_net->tables, list) {
 330                 if (strcmp(table->name, name) == 0)
 331                         return table;
 332         }
 333
 334         list_for_each_entry(tmpl, &template_tables, list) {
 335                 if (strcmp(name, tmpl->name) == 0) {
 336                         struct module *owner = tmpl->owner;
 337
 338                         if (!try_module_get(owner))
 339                                 goto out;
 340
 341                         mutex_unlock(mutex);
 342
 343                         *error = tmpl->table_init(net);
 344                         if (*error) {
 345                                 module_put(owner);
 346                                 return NULL;
 347                         }
 348
 349                         mutex_lock(mutex);
 350                         module_put(owner);
 351                         break;
 352                 }
 353         }
 354
 355         list_for_each_entry(table, &ebt_net->tables, list) {
 356                 if (strcmp(table->name, name) == 0)
 357                         return table;
 358         }
 359
 360 out:
 361         *error = -ENOENT;
 362         mutex_unlock(mutex);
 363         return NULL;
 364 }
 365
 366 static void *
 367 find_inlist_lock(struct net *net, const char *name, const char *prefix,
 368                  int *error, struct mutex *mutex)
 369 {
 370         return try_then_request_module(
 371                         find_inlist_lock_noload(net, name, error, mutex),
 372                         "%s%s", prefix, name);
 373 }
 374
 375 static inline struct ebt_table *
 376 find_table_lock(struct net *net, const char *name, int *error,
 377                 struct mutex *mutex)
 378 {
 379         return find_inlist_lock(net, name, "ebtable_", error, mutex);
 380 }
 381
 382 static inline void ebt_free_table_info(struct ebt_table_info *info)
 383 {
 384         int i;
 385
 386         if (info->chainstack) {
 387                 for_each_possible_cpu(i)
 388                         vfree(info->chainstack[i]);
 389                 vfree(info->chainstack);
 390         }
 391 }
 392 static inline int
 393 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 394                 unsigned int *cnt)
 395 {
 396         const struct ebt_entry *e = par->entryinfo;
 397         struct xt_match *match;
 398         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 399         int ret;
 400
 401         if (left < sizeof(struct ebt_entry_match) ||
 402             left - sizeof(struct ebt_entry_match) < m->match_size)
 403                 return -EINVAL;
 404
 405         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 406         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 407                 if (!IS_ERR(match))
 408                         module_put(match->me);
 409                 request_module("ebt_%s", m->u.name);
 410                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 411         }
 412         if (IS_ERR(match))
 413                 return PTR_ERR(match);
 414         m->u.match = match;
 415
 416         par->match     = match;
 417         par->matchinfo = m->data;
 418         ret = xt_check_match(par, m->match_size,
 419               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 420         if (ret < 0) {
 421                 module_put(match->me);
 422                 return ret;
 423         }
 424
 425         (*cnt)++;
 426         return 0;
 427 }
 428
 429 static inline int
 430 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 431                   unsigned int *cnt)
 432 {
 433         const struct ebt_entry *e = par->entryinfo;
 434         struct xt_target *watcher;
 435         size_t left = ((char *)e + e->target_offset) - (char *)w;
 436         int ret;
 437
 438         if (left < sizeof(struct ebt_entry_watcher) ||
 439            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 440                 return -EINVAL;
 441
 442         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 443         if (IS_ERR(watcher))
 444                 return PTR_ERR(watcher);
 445
 446         if (watcher->family != NFPROTO_BRIDGE) {
 447                 module_put(watcher->me);
 448                 return -ENOENT;
 449         }
 450
 451         w->u.watcher = watcher;
 452
 453         par->target   = watcher;
 454         par->targinfo = w->data;
 455         ret = xt_check_target(par, w->watcher_size,
 456               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 457         if (ret < 0) {
 458                 module_put(watcher->me);
 459                 return ret;
 460         }
 461
 462         (*cnt)++;
 463         return 0;
 464 }
 465
 466 static int ebt_verify_pointers(const struct ebt_replace *repl,
 467                                struct ebt_table_info *newinfo)
 468 {
 469         unsigned int limit = repl->entries_size;
 470         unsigned int valid_hooks = repl->valid_hooks;
 471         unsigned int offset = 0;
 472         int i;
 473
 474         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 475                 newinfo->hook_entry[i] = NULL;
 476
 477         newinfo->entries_size = repl->entries_size;
 478         newinfo->nentries = repl->nentries;
 479
 480         while (offset < limit) {
 481                 size_t left = limit - offset;
 482                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 483
 484                 if (left < sizeof(unsigned int))
 485                         break;
 486
 487                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 488                         if ((valid_hooks & (1 << i)) == 0)
 489                                 continue;
 490                         if ((char __user *)repl->hook_entry[i] ==
 491                              repl->entries + offset)
 492                                 break;
 493                 }
 494
 495                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 496                         if (e->bitmask != 0) {
 497                                 /* we make userspace set this right,
 498                                  * so there is no misunderstanding
 499                                  */
 500                                 return -EINVAL;
 501                         }
 502                         if (i != NF_BR_NUMHOOKS)
 503                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 504                         if (left < sizeof(struct ebt_entries))
 505                                 break;
 506                         offset += sizeof(struct ebt_entries);
 507                 } else {
 508                         if (left < sizeof(struct ebt_entry))
 509                                 break;
 510                         if (left < e->next_offset)
 511                                 break;
 512                         if (e->next_offset < sizeof(struct ebt_entry))
 513                                 return -EINVAL;
 514                         offset += e->next_offset;
 515                 }
 516         }
 517         if (offset != limit)
 518                 return -EINVAL;
 519
 520         /* check if all valid hooks have a chain */
 521         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 522                 if (!newinfo->hook_entry[i] &&
 523                    (valid_hooks & (1 << i)))
 524                         return -EINVAL;
 525         }
 526         return 0;
 527 }
 528
 529 /* this one is very careful, as it is the first function
 530  * to parse the userspace data
 531  */
 532 static inline int
 533 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 534                                const struct ebt_table_info *newinfo,
 535                                unsigned int *n, unsigned int *cnt,
 536                                unsigned int *totalcnt, unsigned int *udc_cnt)
 537 {
 538         int i;
 539
 540         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 541                 if ((void *)e == (void *)newinfo->hook_entry[i])
 542                         break;
 543         }
 544         /* beginning of a new chain
 545          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 546          */
 547         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 548                 /* this checks if the previous chain has as many entries
 549                  * as it said it has
 550                  */
 551                 if (*n != *cnt)
 552                         return -EINVAL;
 553
 554                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 555                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 556                         /* only RETURN from udc */
 557                         if (i != NF_BR_NUMHOOKS ||
 558                            ((struct ebt_entries *)e)->policy != EBT_RETURN)
 559                                 return -EINVAL;
 560                 }
 561                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 562                         (*udc_cnt)++;
 563                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
 564                         return -EINVAL;
 565                 *n = ((struct ebt_entries *)e)->nentries;
 566                 *cnt = 0;
 567                 return 0;
 568         }
 569         /* a plain old entry, heh */
 570         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 571            e->watchers_offset > e->target_offset ||
 572            e->target_offset >= e->next_offset)
 573                 return -EINVAL;
 574
 575         /* this is not checked anywhere else */
 576         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
 577                 return -EINVAL;
 578
 579         (*cnt)++;
 580         (*totalcnt)++;
 581         return 0;
 582 }
 583
 584 struct ebt_cl_stack {
 585         struct ebt_chainstack cs;
 586         int from;
 587         unsigned int hookmask;
 588 };
 589
 590 /* We need these positions to check that the jumps to a different part of the
 591  * entries is a jump to the beginning of a new chain.
 592  */
 593 static inline int
 594 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 595                       unsigned int *n, struct ebt_cl_stack *udc)
 596 {
 597         int i;
 598
 599         /* we're only interested in chain starts */
 600         if (e->bitmask)
 601                 return 0;
 602         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 603                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 604                         break;
 605         }
 606         /* only care about udc */
 607         if (i != NF_BR_NUMHOOKS)
 608                 return 0;
 609
 610         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 611         /* these initialisations are depended on later in check_chainloops() */
 612         udc[*n].cs.n = 0;
 613         udc[*n].hookmask = 0;
 614
 615         (*n)++;
 616         return 0;
 617 }
 618
 619 static inline int
 620 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 621 {
 622         struct xt_mtdtor_param par;
 623
 624         if (i && (*i)-- == 0)
 625                 return 1;
 626
 627         par.net       = net;
 628         par.match     = m->u.match;
 629         par.matchinfo = m->data;
 630         par.family    = NFPROTO_BRIDGE;
 631         if (par.match->destroy != NULL)
 632                 par.match->destroy(&par);
 633         module_put(par.match->me);
 634         return 0;
 635 }
 636
 637 static inline int
 638 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 639 {
 640         struct xt_tgdtor_param par;
 641
 642         if (i && (*i)-- == 0)
 643                 return 1;
 644
 645         par.net      = net;
 646         par.target   = w->u.watcher;
 647         par.targinfo = w->data;
 648         par.family   = NFPROTO_BRIDGE;
 649         if (par.target->destroy != NULL)
 650                 par.target->destroy(&par);
 651         module_put(par.target->me);
 652         return 0;
 653 }
 654
 655 static inline int
 656 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 657 {
 658         struct xt_tgdtor_param par;
 659         struct ebt_entry_target *t;
 660
 661         if (e->bitmask == 0)
 662                 return 0;
 663         /* we're done */
 664         if (cnt && (*cnt)-- == 0)
 665                 return 1;
 666         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 667         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 668         t = ebt_get_target(e);
 669
 670         par.net      = net;
 671         par.target   = t->u.target;
 672         par.targinfo = t->data;
 673         par.family   = NFPROTO_BRIDGE;
 674         if (par.target->destroy != NULL)
 675                 par.target->destroy(&par);
 676         module_put(par.target->me);
 677         return 0;
 678 }
 679
 680 static inline int
 681 ebt_check_entry(struct ebt_entry *e, struct net *net,
 682                 const struct ebt_table_info *newinfo,
 683                 const char *name, unsigned int *cnt,
 684                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 685 {
 686         struct ebt_entry_target *t;
 687         struct xt_target *target;
 688         unsigned int i, j, hook = 0, hookmask = 0;
 689         size_t gap;
 690         int ret;
 691         struct xt_mtchk_param mtpar;
 692         struct xt_tgchk_param tgpar;
 693
 694         /* don't mess with the struct ebt_entries */
 695         if (e->bitmask == 0)
 696                 return 0;
 697
 698         if (e->bitmask & ~EBT_F_MASK)
 699                 return -EINVAL;
 700
 701         if (e->invflags & ~EBT_INV_MASK)
 702                 return -EINVAL;
 703
 704         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
 705                 return -EINVAL;
 706
 707         /* what hook do we belong to? */
 708         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 709                 if (!newinfo->hook_entry[i])
 710                         continue;
 711                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 712                         hook = i;
 713                 else
 714                         break;
 715         }
 716         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 717          * a base chain
 718          */
 719         if (i < NF_BR_NUMHOOKS)
 720                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 721         else {
 722                 for (i = 0; i < udc_cnt; i++)
 723                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 724                                 break;
 725                 if (i == 0)
 726                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 727                 else
 728                         hookmask = cl_s[i - 1].hookmask;
 729         }
 730         i = 0;
 731
 732         memset(&mtpar, 0, sizeof(mtpar));
 733         memset(&tgpar, 0, sizeof(tgpar));
 734         mtpar.net       = tgpar.net       = net;
 735         mtpar.table     = tgpar.table     = name;
 736         mtpar.entryinfo = tgpar.entryinfo = e;
 737         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 738         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 739         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 740         if (ret != 0)
 741                 goto cleanup_matches;
 742         j = 0;
 743         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 744         if (ret != 0)
 745                 goto cleanup_watchers;
 746         t = ebt_get_target(e);
 747         gap = e->next_offset - e->target_offset;
 748
 749         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 750         if (IS_ERR(target)) {
 751                 ret = PTR_ERR(target);
 752                 goto cleanup_watchers;
 753         }
 754
 755         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 756         if (target->family != NFPROTO_BRIDGE) {
 757                 module_put(target->me);
 758                 ret = -ENOENT;
 759                 goto cleanup_watchers;
 760         }
 761
 762         t->u.target = target;
 763         if (t->u.target == &ebt_standard_target) {
 764                 if (gap < sizeof(struct ebt_standard_target)) {
 765                         ret = -EFAULT;
 766                         goto cleanup_watchers;
 767                 }
 768                 if (((struct ebt_standard_target *)t)->verdict <
 769                    -NUM_STANDARD_TARGETS) {
 770                         ret = -EFAULT;
 771                         goto cleanup_watchers;
 772                 }
 773         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 774                 module_put(t->u.target->me);
 775                 ret = -EFAULT;
 776                 goto cleanup_watchers;
 777         }
 778
 779         tgpar.target   = target;
 780         tgpar.targinfo = t->data;
 781         ret = xt_check_target(&tgpar, t->target_size,
 782               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 783         if (ret < 0) {
 784                 module_put(target->me);
 785                 goto cleanup_watchers;
 786         }
 787         (*cnt)++;
 788         return 0;
 789 cleanup_watchers:
 790         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 791 cleanup_matches:
 792         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 793         return ret;
 794 }
 795
 796 /* checks for loops and sets the hook mask for udc
 797  * the hook mask for udc tells us from which base chains the udc can be
 798  * accessed. This mask is a parameter to the check() functions of the extensions
 799  */
 800 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 801                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 802 {
 803         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 804         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 805         const struct ebt_entry_target *t;
 806
 807         while (pos < nentries || chain_nr != -1) {
 808                 /* end of udc, go back one 'recursion' step */
 809                 if (pos == nentries) {
 810                         /* put back values of the time when this chain was called */
 811                         e = cl_s[chain_nr].cs.e;
 812                         if (cl_s[chain_nr].from != -1)
 813                                 nentries =
 814                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 815                         else
 816                                 nentries = chain->nentries;
 817                         pos = cl_s[chain_nr].cs.n;
 818                         /* make sure we won't see a loop that isn't one */
 819                         cl_s[chain_nr].cs.n = 0;
 820                         chain_nr = cl_s[chain_nr].from;
 821                         if (pos == nentries)
 822                                 continue;
 823                 }
 824                 t = ebt_get_target_c(e);
 825                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 826                         goto letscontinue;
 827                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 828                    e->next_offset)
 829                         return -1;
 830
 831                 verdict = ((struct ebt_standard_target *)t)->verdict;
 832                 if (verdict >= 0) { /* jump to another chain */
 833                         struct ebt_entries *hlp2 =
 834                            (struct ebt_entries *)(base + verdict);
 835                         for (i = 0; i < udc_cnt; i++)
 836                                 if (hlp2 == cl_s[i].cs.chaininfo)
 837                                         break;
 838                         /* bad destination or loop */
 839                         if (i == udc_cnt)
 840                                 return -1;
 841
 842                         if (cl_s[i].cs.n)
 843                                 return -1;
 844
 845                         if (cl_s[i].hookmask & (1 << hooknr))
 846                                 goto letscontinue;
 847                         /* this can't be 0, so the loop test is correct */
 848                         cl_s[i].cs.n = pos + 1;
 849                         pos = 0;
 850                         cl_s[i].cs.e = ebt_next_entry(e);
 851                         e = (struct ebt_entry *)(hlp2->data);
 852                         nentries = hlp2->nentries;
 853                         cl_s[i].from = chain_nr;
 854                         chain_nr = i;
 855                         /* this udc is accessible from the base chain for hooknr */
 856                         cl_s[i].hookmask |= (1 << hooknr);
 857                         continue;
 858                 }
 859 letscontinue:
 860                 e = ebt_next_entry(e);
 861                 pos++;
 862         }
 863         return 0;
 864 }
 865
 866 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 867 static int translate_table(struct net *net, const char *name,
 868                            struct ebt_table_info *newinfo)
 869 {
 870         unsigned int i, j, k, udc_cnt;
 871         int ret;
 872         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 873
 874         i = 0;
 875         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 876                 i++;
 877         if (i == NF_BR_NUMHOOKS)
 878                 return -EINVAL;
 879
 880         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
 881                 return -EINVAL;
 882
 883         /* make sure chains are ordered after each other in same order
 884          * as their corresponding hooks
 885          */
 886         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 887                 if (!newinfo->hook_entry[j])
 888                         continue;
 889                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
 890                         return -EINVAL;
 891
 892                 i = j;
 893         }
 894
 895         /* do some early checkings and initialize some things */
 896         i = 0; /* holds the expected nr. of entries for the chain */
 897         j = 0; /* holds the up to now counted entries for the chain */
 898         k = 0; /* holds the total nr. of entries, should equal
 899                 * newinfo->nentries afterwards
 900                 */
 901         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 902         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 903            ebt_check_entry_size_and_hooks, newinfo,
 904            &i, &j, &k, &udc_cnt);
 905
 906         if (ret != 0)
 907                 return ret;
 908
 909         if (i != j)
 910                 return -EINVAL;
 911
 912         if (k != newinfo->nentries)
 913                 return -EINVAL;
 914
 915         /* get the location of the udc, put them in an array
 916          * while we're at it, allocate the chainstack
 917          */
 918         if (udc_cnt) {
 919                 /* this will get free'd in do_replace()/ebt_register_table()
 920                  * if an error occurs
 921                  */
 922                 newinfo->chainstack =
 923                         vmalloc(array_size(nr_cpu_ids,
 924                                            sizeof(*(newinfo->chainstack))));
 925                 if (!newinfo->chainstack)
 926                         return -ENOMEM;
 927                 for_each_possible_cpu(i) {
 928                         newinfo->chainstack[i] =
 929                           vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 930                         if (!newinfo->chainstack[i]) {
 931                                 while (i)
 932                                         vfree(newinfo->chainstack[--i]);
 933                                 vfree(newinfo->chainstack);
 934                                 newinfo->chainstack = NULL;
 935                                 return -ENOMEM;
 936                         }
 937                 }
 938
 939                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 940                 if (!cl_s)
 941                         return -ENOMEM;
 942                 i = 0; /* the i'th udc */
 943                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 944                    ebt_get_udc_positions, newinfo, &i, cl_s);
 945                 /* sanity check */
 946                 if (i != udc_cnt) {
 947                         vfree(cl_s);
 948                         return -EFAULT;
 949                 }
 950         }
 951
 952         /* Check for loops */
 953         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 954                 if (newinfo->hook_entry[i])
 955                         if (check_chainloops(newinfo->hook_entry[i],
 956                            cl_s, udc_cnt, i, newinfo->entries)) {
 957                                 vfree(cl_s);
 958                                 return -EINVAL;
 959                         }
 960
 961         /* we now know the following (along with E=mc²):
 962          *  - the nr of entries in each chain is right
 963          *  - the size of the allocated space is right
 964          *  - all valid hooks have a corresponding chain
 965          *  - there are no loops
 966          *  - wrong data can still be on the level of a single entry
 967          *  - could be there are jumps to places that are not the
 968          *    beginning of a chain. This can only occur in chains that
 969          *    are not accessible from any base chains, so we don't care.
 970          */
 971
 972         /* used to know what we need to clean up if something goes wrong */
 973         i = 0;
 974         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 975            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 976         if (ret != 0) {
 977                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 978                                   ebt_cleanup_entry, net, &i);
 979         }
 980         vfree(cl_s);
 981         return ret;
 982 }
 983
 984 /* called under write_lock */
 985 static void get_counters(const struct ebt_counter *oldcounters,
 986                          struct ebt_counter *counters, unsigned int nentries)
 987 {
 988         int i, cpu;
 989         struct ebt_counter *counter_base;
 990
 991         /* counters of cpu 0 */
 992         memcpy(counters, oldcounters,
 993                sizeof(struct ebt_counter) * nentries);
 994
 995         /* add other counters to those of cpu 0 */
 996         for_each_possible_cpu(cpu) {
 997                 if (cpu == 0)
 998                         continue;
 999                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
1000                 for (i = 0; i < nentries; i++)
1001                         ADD_COUNTER(counters[i], counter_base[i].bcnt,
1002                                     counter_base[i].pcnt);
1003         }
1004 }
1005
1006 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1007                               struct ebt_table_info *newinfo)
1008 {
1009         int ret;
1010         struct ebt_counter *counterstmp = NULL;
1011         /* used to be able to unlock earlier */
1012         struct ebt_table_info *table;
1013         struct ebt_table *t;
1014
1015         /* the user wants counters back
1016          * the check on the size is done later, when we have the lock
1017          */
1018         if (repl->num_counters) {
1019                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1020                 counterstmp = vmalloc(size);
1021                 if (!counterstmp)
1022                         return -ENOMEM;
1023         }
1024
1025         newinfo->chainstack = NULL;
1026         ret = ebt_verify_pointers(repl, newinfo);
1027         if (ret != 0)
1028                 goto free_counterstmp;
1029
1030         ret = translate_table(net, repl->name, newinfo);
1031
1032         if (ret != 0)
1033                 goto free_counterstmp;
1034
1035         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1036         if (!t) {
1037                 ret = -ENOENT;
1038                 goto free_iterate;
1039         }
1040
1041         /* the table doesn't like it */
1042         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1043                 goto free_unlock;
1044
1045         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1046                 ret = -EINVAL;
1047                 goto free_unlock;
1048         }
1049
1050         /* we have the mutex lock, so no danger in reading this pointer */
1051         table = t->private;
1052         /* make sure the table can only be rmmod'ed if it contains no rules */
1053         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1054                 ret = -ENOENT;
1055                 goto free_unlock;
1056         } else if (table->nentries && !newinfo->nentries)
1057                 module_put(t->me);
1058         /* we need an atomic snapshot of the counters */
1059         write_lock_bh(&t->lock);
1060         if (repl->num_counters)
1061                 get_counters(t->private->counters, counterstmp,
1062                    t->private->nentries);
1063
1064         t->private = newinfo;
1065         write_unlock_bh(&t->lock);
1066         mutex_unlock(&ebt_mutex);
1067         /* so, a user can change the chains while having messed up her counter
1068          * allocation. Only reason why this is done is because this way the lock
1069          * is held only once, while this doesn't bring the kernel into a
1070          * dangerous state.
1071          */
1072         if (repl->num_counters &&
1073            copy_to_user(repl->counters, counterstmp,
1074            repl->num_counters * sizeof(struct ebt_counter))) {
1075                 /* Silent error, can't fail, new table is already in place */
1076                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1077         }
1078
1079         /* decrease module count and free resources */
1080         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1081                           ebt_cleanup_entry, net, NULL);
1082
1083         vfree(table->entries);
1084         ebt_free_table_info(table);
1085         vfree(table);
1086         vfree(counterstmp);
1087
1088         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1089                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1090         return ret;
1091
1092 free_unlock:
1093         mutex_unlock(&ebt_mutex);
1094 free_iterate:
1095         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1096                           ebt_cleanup_entry, net, NULL);
1097 free_counterstmp:
1098         vfree(counterstmp);
1099         /* can be initialized in translate_table() */
1100         ebt_free_table_info(newinfo);
1101         return ret;
1102 }
1103
1104 /* replace the table */
1105 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1106 {
1107         int ret, countersize;
1108         struct ebt_table_info *newinfo;
1109         struct ebt_replace tmp;
1110
1111         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1112                 return -EFAULT;
1113
1114         if (len != sizeof(tmp) + tmp.entries_size)
1115                 return -EINVAL;
1116
1117         if (tmp.entries_size == 0)
1118                 return -EINVAL;
1119
1120         /* overflow check */
1121         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1122                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1123                 return -ENOMEM;
1124         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1125                 return -ENOMEM;
1126
1127         tmp.name[sizeof(tmp.name) - 1] = 0;
1128
1129         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1130         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1131         if (!newinfo)
1132                 return -ENOMEM;
1133
1134         if (countersize)
1135                 memset(newinfo->counters, 0, countersize);
1136
1137         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1138         if (!newinfo->entries) {
1139                 ret = -ENOMEM;
1140                 goto free_newinfo;
1141         }
1142         if (copy_from_user(
1143            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1144                 ret = -EFAULT;
1145                 goto free_entries;
1146         }
1147
1148         ret = do_replace_finish(net, &tmp, newinfo);
1149         if (ret == 0)
1150                 return ret;
1151 free_entries:
1152         vfree(newinfo->entries);
1153 free_newinfo:
1154         vfree(newinfo);
1155         return ret;
1156 }
1157
1158 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1159 {
1160         mutex_lock(&ebt_mutex);
1161         list_del(&table->list);
1162         mutex_unlock(&ebt_mutex);
1163         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1164                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1165         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1166                           ebt_cleanup_entry, net, NULL);
1167         if (table->private->nentries)
1168                 module_put(table->me);
1169         vfree(table->private->entries);
1170         ebt_free_table_info(table->private);
1171         vfree(table->private);
1172         kfree(table->ops);
1173         kfree(table);
1174 }
1175
1176 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1177                        const struct nf_hook_ops *template_ops)
1178 {
1179         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1180         struct ebt_table_info *newinfo;
1181         struct ebt_table *t, *table;
1182         struct nf_hook_ops *ops;
1183         unsigned int num_ops;
1184         struct ebt_replace_kernel *repl;
1185         int ret, i, countersize;
1186         void *p;
1187
1188         if (input_table == NULL || (repl = input_table->table) == NULL ||
1189             repl->entries == NULL || repl->entries_size == 0 ||
1190             repl->counters != NULL || input_table->private != NULL)
1191                 return -EINVAL;
1192
1193         /* Don't add one table to multiple lists. */
1194         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1195         if (!table) {
1196                 ret = -ENOMEM;
1197                 goto out;
1198         }
1199
1200         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1201         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1202         ret = -ENOMEM;
1203         if (!newinfo)
1204                 goto free_table;
1205
1206         p = vmalloc(repl->entries_size);
1207         if (!p)
1208                 goto free_newinfo;
1209
1210         memcpy(p, repl->entries, repl->entries_size);
1211         newinfo->entries = p;
1212
1213         newinfo->entries_size = repl->entries_size;
1214         newinfo->nentries = repl->nentries;
1215
1216         if (countersize)
1217                 memset(newinfo->counters, 0, countersize);
1218
1219         /* fill in newinfo and parse the entries */
1220         newinfo->chainstack = NULL;
1221         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1222                 if ((repl->valid_hooks & (1 << i)) == 0)
1223                         newinfo->hook_entry[i] = NULL;
1224                 else
1225                         newinfo->hook_entry[i] = p +
1226                                 ((char *)repl->hook_entry[i] - repl->entries);
1227         }
1228         ret = translate_table(net, repl->name, newinfo);
1229         if (ret != 0)
1230                 goto free_chainstack;
1231
1232         if (table->check && table->check(newinfo, table->valid_hooks)) {
1233                 ret = -EINVAL;
1234                 goto free_chainstack;
1235         }
1236
1237         table->private = newinfo;
1238         rwlock_init(&table->lock);
1239         mutex_lock(&ebt_mutex);
1240         list_for_each_entry(t, &ebt_net->tables, list) {
1241                 if (strcmp(t->name, table->name) == 0) {
1242                         ret = -EEXIST;
1243                         goto free_unlock;
1244                 }
1245         }
1246
1247         /* Hold a reference count if the chains aren't empty */
1248         if (newinfo->nentries && !try_module_get(table->me)) {
1249                 ret = -ENOENT;
1250                 goto free_unlock;
1251         }
1252
1253         num_ops = hweight32(table->valid_hooks);
1254         if (num_ops == 0) {
1255                 ret = -EINVAL;
1256                 goto free_unlock;
1257         }
1258
1259         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1260         if (!ops) {
1261                 ret = -ENOMEM;
1262                 if (newinfo->nentries)
1263                         module_put(table->me);
1264                 goto free_unlock;
1265         }
1266
1267         for (i = 0; i < num_ops; i++)
1268                 ops[i].priv = table;
1269
1270         list_add(&table->list, &ebt_net->tables);
1271         mutex_unlock(&ebt_mutex);
1272
1273         table->ops = ops;
1274         ret = nf_register_net_hooks(net, ops, num_ops);
1275         if (ret)
1276                 __ebt_unregister_table(net, table);
1277
1278         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1279                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1280         return ret;
1281 free_unlock:
1282         mutex_unlock(&ebt_mutex);
1283 free_chainstack:
1284         ebt_free_table_info(newinfo);
1285         vfree(newinfo->entries);
1286 free_newinfo:
1287         vfree(newinfo);
1288 free_table:
1289         kfree(table);
1290 out:
1291         return ret;
1292 }
1293
1294 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1295 {
1296         struct ebt_template *tmpl;
1297
1298         mutex_lock(&ebt_mutex);
1299         list_for_each_entry(tmpl, &template_tables, list) {
1300                 if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1301                         mutex_unlock(&ebt_mutex);
1302                         return -EEXIST;
1303                 }
1304         }
1305
1306         tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1307         if (!tmpl) {
1308                 mutex_unlock(&ebt_mutex);
1309                 return -ENOMEM;
1310         }
1311
1312         tmpl->table_init = table_init;
1313         strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1314         tmpl->owner = t->me;
1315         list_add(&tmpl->list, &template_tables);
1316
1317         mutex_unlock(&ebt_mutex);
1318         return 0;
1319 }
1320 EXPORT_SYMBOL(ebt_register_template);
1321
1322 void ebt_unregister_template(const struct ebt_table *t)
1323 {
1324         struct ebt_template *tmpl;
1325
1326         mutex_lock(&ebt_mutex);
1327         list_for_each_entry(tmpl, &template_tables, list) {
1328                 if (strcmp(t->name, tmpl->name))
1329                         continue;
1330
1331                 list_del(&tmpl->list);
1332                 mutex_unlock(&ebt_mutex);
1333                 kfree(tmpl);
1334                 return;
1335         }
1336
1337         mutex_unlock(&ebt_mutex);
1338         WARN_ON_ONCE(1);
1339 }
1340 EXPORT_SYMBOL(ebt_unregister_template);
1341
1342 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1343 {
1344         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1345         struct ebt_table *t;
1346
1347         mutex_lock(&ebt_mutex);
1348
1349         list_for_each_entry(t, &ebt_net->tables, list) {
1350                 if (strcmp(t->name, name) == 0) {
1351                         mutex_unlock(&ebt_mutex);
1352                         return t;
1353                 }
1354         }
1355
1356         mutex_unlock(&ebt_mutex);
1357         return NULL;
1358 }
1359
1360 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1361 {
1362         struct ebt_table *table = __ebt_find_table(net, name);
1363
1364         if (table)
1365                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1366 }
1367 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1368
1369 void ebt_unregister_table(struct net *net, const char *name)
1370 {
1371         struct ebt_table *table = __ebt_find_table(net, name);
1372
1373         if (table)
1374                 __ebt_unregister_table(net, table);
1375 }
1376
1377 /* userspace just supplied us with counters */
1378 static int do_update_counters(struct net *net, const char *name,
1379                               struct ebt_counter __user *counters,
1380                               unsigned int num_counters, unsigned int len)
1381 {
1382         int i, ret;
1383         struct ebt_counter *tmp;
1384         struct ebt_table *t;
1385
1386         if (num_counters == 0)
1387                 return -EINVAL;
1388
1389         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1390         if (!tmp)
1391                 return -ENOMEM;
1392
1393         t = find_table_lock(net, name, &ret, &ebt_mutex);
1394         if (!t)
1395                 goto free_tmp;
1396
1397         if (num_counters != t->private->nentries) {
1398                 ret = -EINVAL;
1399                 goto unlock_mutex;
1400         }
1401
1402         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1403                 ret = -EFAULT;
1404                 goto unlock_mutex;
1405         }
1406
1407         /* we want an atomic add of the counters */
1408         write_lock_bh(&t->lock);
1409
1410         /* we add to the counters of the first cpu */
1411         for (i = 0; i < num_counters; i++)
1412                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1413
1414         write_unlock_bh(&t->lock);
1415         ret = 0;
1416 unlock_mutex:
1417         mutex_unlock(&ebt_mutex);
1418 free_tmp:
1419         vfree(tmp);
1420         return ret;
1421 }
1422
1423 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1424 {
1425         struct ebt_replace hlp;
1426
1427         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1428                 return -EFAULT;
1429
1430         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1431                 return -EINVAL;
1432
1433         return do_update_counters(net, hlp.name, hlp.counters,
1434                                   hlp.num_counters, len);
1435 }
1436
1437 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1438                                   const char *data, int entrysize,
1439                                   int usersize, int datasize, u8 revision)
1440 {
1441         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1442
1443         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1444          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1445          */
1446         strlcpy(name, _name, sizeof(name));
1447         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1448             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1449             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1450             xt_data_to_user(um + entrysize, data, usersize, datasize,
1451                             XT_ALIGN(datasize)))
1452                 return -EFAULT;
1453
1454         return 0;
1455 }
1456
1457 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1458                                     const char *base, char __user *ubase)
1459 {
1460         return ebt_obj_to_user(ubase + ((char *)m - base),
1461                                m->u.match->name, m->data, sizeof(*m),
1462                                m->u.match->usersize, m->match_size,
1463                                m->u.match->revision);
1464 }
1465
1466 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1467                                       const char *base, char __user *ubase)
1468 {
1469         return ebt_obj_to_user(ubase + ((char *)w - base),
1470                                w->u.watcher->name, w->data, sizeof(*w),
1471                                w->u.watcher->usersize, w->watcher_size,
1472                                w->u.watcher->revision);
1473 }
1474
1475 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1476                                     char __user *ubase)
1477 {
1478         int ret;
1479         char __user *hlp;
1480         const struct ebt_entry_target *t;
1481
1482         if (e->bitmask == 0) {
1483                 /* special case !EBT_ENTRY_OR_ENTRIES */
1484                 if (copy_to_user(ubase + ((char *)e - base), e,
1485                                  sizeof(struct ebt_entries)))
1486                         return -EFAULT;
1487                 return 0;
1488         }
1489
1490         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1491                 return -EFAULT;
1492
1493         hlp = ubase + (((char *)e + e->target_offset) - base);
1494         t = ebt_get_target_c(e);
1495
1496         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1497         if (ret != 0)
1498                 return ret;
1499         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1500         if (ret != 0)
1501                 return ret;
1502         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1503                               t->u.target->usersize, t->target_size,
1504                               t->u.target->revision);
1505         if (ret != 0)
1506                 return ret;
1507
1508         return 0;
1509 }
1510
1511 static int copy_counters_to_user(struct ebt_table *t,
1512                                  const struct ebt_counter *oldcounters,
1513                                  void __user *user, unsigned int num_counters,
1514                                  unsigned int nentries)
1515 {
1516         struct ebt_counter *counterstmp;
1517         int ret = 0;
1518
1519         /* userspace might not need the counters */
1520         if (num_counters == 0)
1521                 return 0;
1522
1523         if (num_counters != nentries)
1524                 return -EINVAL;
1525
1526         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1527         if (!counterstmp)
1528                 return -ENOMEM;
1529
1530         write_lock_bh(&t->lock);
1531         get_counters(oldcounters, counterstmp, nentries);
1532         write_unlock_bh(&t->lock);
1533
1534         if (copy_to_user(user, counterstmp,
1535            nentries * sizeof(struct ebt_counter)))
1536                 ret = -EFAULT;
1537         vfree(counterstmp);
1538         return ret;
1539 }
1540
1541 /* called with ebt_mutex locked */
1542 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1543                                    const int *len, int cmd)
1544 {
1545         struct ebt_replace tmp;
1546         const struct ebt_counter *oldcounters;
1547         unsigned int entries_size, nentries;
1548         int ret;
1549         char *entries;
1550
1551         if (cmd == EBT_SO_GET_ENTRIES) {
1552                 entries_size = t->private->entries_size;
1553                 nentries = t->private->nentries;
1554                 entries = t->private->entries;
1555                 oldcounters = t->private->counters;
1556         } else {
1557                 entries_size = t->table->entries_size;
1558                 nentries = t->table->nentries;
1559                 entries = t->table->entries;
1560                 oldcounters = t->table->counters;
1561         }
1562
1563         if (copy_from_user(&tmp, user, sizeof(tmp)))
1564                 return -EFAULT;
1565
1566         if (*len != sizeof(struct ebt_replace) + entries_size +
1567            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1568                 return -EINVAL;
1569
1570         if (tmp.nentries != nentries)
1571                 return -EINVAL;
1572
1573         if (tmp.entries_size != entries_size)
1574                 return -EINVAL;
1575
1576         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1577                                         tmp.num_counters, nentries);
1578         if (ret)
1579                 return ret;
1580
1581         /* set the match/watcher/target names right */
1582         return EBT_ENTRY_ITERATE(entries, entries_size,
1583            ebt_entry_to_user, entries, tmp.entries);
1584 }
1585
1586 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1587 /* 32 bit-userspace compatibility definitions. */
1588 struct compat_ebt_replace {
1589         char name[EBT_TABLE_MAXNAMELEN];
1590         compat_uint_t valid_hooks;
1591         compat_uint_t nentries;
1592         compat_uint_t entries_size;
1593         /* start of the chains */
1594         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1595         /* nr of counters userspace expects back */
1596         compat_uint_t num_counters;
1597         /* where the kernel will put the old counters. */
1598         compat_uptr_t counters;
1599         compat_uptr_t entries;
1600 };
1601
1602 /* struct ebt_entry_match, _target and _watcher have same layout */
1603 struct compat_ebt_entry_mwt {
1604         union {
1605                 struct {
1606                         char name[EBT_EXTENSION_MAXNAMELEN];
1607                         u8 revision;
1608                 };
1609                 compat_uptr_t ptr;
1610         } u;
1611         compat_uint_t match_size;
1612         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1613 };
1614
1615 /* account for possible padding between match_size and ->data */
1616 static int ebt_compat_entry_padsize(void)
1617 {
1618         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1619                         sizeof(struct compat_ebt_entry_mwt));
1620         return (int) sizeof(struct ebt_entry_match) -
1621                         sizeof(struct compat_ebt_entry_mwt);
1622 }
1623
1624 static int ebt_compat_match_offset(const struct xt_match *match,
1625                                    unsigned int userlen)
1626 {
1627         /* ebt_among needs special handling. The kernel .matchsize is
1628          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1629          * value is expected.
1630          * Example: userspace sends 4500, ebt_among.c wants 4504.
1631          */
1632         if (unlikely(match->matchsize == -1))
1633                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1634         return xt_compat_match_offset(match);
1635 }
1636
1637 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1638                                 unsigned int *size)
1639 {
1640         const struct xt_match *match = m->u.match;
1641         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1642         int off = ebt_compat_match_offset(match, m->match_size);
1643         compat_uint_t msize = m->match_size - off;
1644
1645         if (WARN_ON(off >= m->match_size))
1646                 return -EINVAL;
1647
1648         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1649             put_user(match->revision, &cm->u.revision) ||
1650             put_user(msize, &cm->match_size))
1651                 return -EFAULT;
1652
1653         if (match->compat_to_user) {
1654                 if (match->compat_to_user(cm->data, m->data))
1655                         return -EFAULT;
1656         } else {
1657                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1658                                     COMPAT_XT_ALIGN(msize)))
1659                         return -EFAULT;
1660         }
1661
1662         *size -= ebt_compat_entry_padsize() + off;
1663         *dstptr = cm->data;
1664         *dstptr += msize;
1665         return 0;
1666 }
1667
1668 static int compat_target_to_user(struct ebt_entry_target *t,
1669                                  void __user **dstptr,
1670                                  unsigned int *size)
1671 {
1672         const struct xt_target *target = t->u.target;
1673         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1674         int off = xt_compat_target_offset(target);
1675         compat_uint_t tsize = t->target_size - off;
1676
1677         if (WARN_ON(off >= t->target_size))
1678                 return -EINVAL;
1679
1680         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1681             put_user(target->revision, &cm->u.revision) ||
1682             put_user(tsize, &cm->match_size))
1683                 return -EFAULT;
1684
1685         if (target->compat_to_user) {
1686                 if (target->compat_to_user(cm->data, t->data))
1687                         return -EFAULT;
1688         } else {
1689                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1690                                     COMPAT_XT_ALIGN(tsize)))
1691                         return -EFAULT;
1692         }
1693
1694         *size -= ebt_compat_entry_padsize() + off;
1695         *dstptr = cm->data;
1696         *dstptr += tsize;
1697         return 0;
1698 }
1699
1700 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1701                                   void __user **dstptr,
1702                                   unsigned int *size)
1703 {
1704         return compat_target_to_user((struct ebt_entry_target *)w,
1705                                                         dstptr, size);
1706 }
1707
1708 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1709                                 unsigned int *size)
1710 {
1711         struct ebt_entry_target *t;
1712         struct ebt_entry __user *ce;
1713         u32 watchers_offset, target_offset, next_offset;
1714         compat_uint_t origsize;
1715         int ret;
1716
1717         if (e->bitmask == 0) {
1718                 if (*size < sizeof(struct ebt_entries))
1719                         return -EINVAL;
1720                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1721                         return -EFAULT;
1722
1723                 *dstptr += sizeof(struct ebt_entries);
1724                 *size -= sizeof(struct ebt_entries);
1725                 return 0;
1726         }
1727
1728         if (*size < sizeof(*ce))
1729                 return -EINVAL;
1730
1731         ce = *dstptr;
1732         if (copy_to_user(ce, e, sizeof(*ce)))
1733                 return -EFAULT;
1734
1735         origsize = *size;
1736         *dstptr += sizeof(*ce);
1737
1738         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1739         if (ret)
1740                 return ret;
1741         watchers_offset = e->watchers_offset - (origsize - *size);
1742
1743         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1744         if (ret)
1745                 return ret;
1746         target_offset = e->target_offset - (origsize - *size);
1747
1748         t = ebt_get_target(e);
1749
1750         ret = compat_target_to_user(t, dstptr, size);
1751         if (ret)
1752                 return ret;
1753         next_offset = e->next_offset - (origsize - *size);
1754
1755         if (put_user(watchers_offset, &ce->watchers_offset) ||
1756             put_user(target_offset, &ce->target_offset) ||
1757             put_user(next_offset, &ce->next_offset))
1758                 return -EFAULT;
1759
1760         *size -= sizeof(*ce);
1761         return 0;
1762 }
1763
1764 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1765 {
1766         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1767         *off += ebt_compat_entry_padsize();
1768         return 0;
1769 }
1770
1771 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1772 {
1773         *off += xt_compat_target_offset(w->u.watcher);
1774         *off += ebt_compat_entry_padsize();
1775         return 0;
1776 }
1777
1778 static int compat_calc_entry(const struct ebt_entry *e,
1779                              const struct ebt_table_info *info,
1780                              const void *base,
1781                              struct compat_ebt_replace *newinfo)
1782 {
1783         const struct ebt_entry_target *t;
1784         unsigned int entry_offset;
1785         int off, ret, i;
1786
1787         if (e->bitmask == 0)
1788                 return 0;
1789
1790         off = 0;
1791         entry_offset = (void *)e - base;
1792
1793         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1794         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1795
1796         t = ebt_get_target_c(e);
1797
1798         off += xt_compat_target_offset(t->u.target);
1799         off += ebt_compat_entry_padsize();
1800
1801         newinfo->entries_size -= off;
1802
1803         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1804         if (ret)
1805                 return ret;
1806
1807         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1808                 const void *hookptr = info->hook_entry[i];
1809                 if (info->hook_entry[i] &&
1810                     (e < (struct ebt_entry *)(base - hookptr))) {
1811                         newinfo->hook_entry[i] -= off;
1812                         pr_debug("0x%08X -> 0x%08X\n",
1813                                         newinfo->hook_entry[i] + off,
1814                                         newinfo->hook_entry[i]);
1815                 }
1816         }
1817
1818         return 0;
1819 }
1820
1821 static int ebt_compat_init_offsets(unsigned int number)
1822 {
1823         if (number > INT_MAX)
1824                 return -EINVAL;
1825
1826         /* also count the base chain policies */
1827         number += NF_BR_NUMHOOKS;
1828
1829         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1830 }
1831
1832 static int compat_table_info(const struct ebt_table_info *info,
1833                              struct compat_ebt_replace *newinfo)
1834 {
1835         unsigned int size = info->entries_size;
1836         const void *entries = info->entries;
1837         int ret;
1838
1839         newinfo->entries_size = size;
1840         ret = ebt_compat_init_offsets(info->nentries);
1841         if (ret)
1842                 return ret;
1843
1844         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1845                                                         entries, newinfo);
1846 }
1847
1848 static int compat_copy_everything_to_user(struct ebt_table *t,
1849                                           void __user *user, int *len, int cmd)
1850 {
1851         struct compat_ebt_replace repl, tmp;
1852         struct ebt_counter *oldcounters;
1853         struct ebt_table_info tinfo;
1854         int ret;
1855         void __user *pos;
1856
1857         memset(&tinfo, 0, sizeof(tinfo));
1858
1859         if (cmd == EBT_SO_GET_ENTRIES) {
1860                 tinfo.entries_size = t->private->entries_size;
1861                 tinfo.nentries = t->private->nentries;
1862                 tinfo.entries = t->private->entries;
1863                 oldcounters = t->private->counters;
1864         } else {
1865                 tinfo.entries_size = t->table->entries_size;
1866                 tinfo.nentries = t->table->nentries;
1867                 tinfo.entries = t->table->entries;
1868                 oldcounters = t->table->counters;
1869         }
1870
1871         if (copy_from_user(&tmp, user, sizeof(tmp)))
1872                 return -EFAULT;
1873
1874         if (tmp.nentries != tinfo.nentries ||
1875            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1876                 return -EINVAL;
1877
1878         memcpy(&repl, &tmp, sizeof(repl));
1879         if (cmd == EBT_SO_GET_ENTRIES)
1880                 ret = compat_table_info(t->private, &repl);
1881         else
1882                 ret = compat_table_info(&tinfo, &repl);
1883         if (ret)
1884                 return ret;
1885
1886         if (*len != sizeof(tmp) + repl.entries_size +
1887            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1888                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1889                                 *len, tinfo.entries_size, repl.entries_size);
1890                 return -EINVAL;
1891         }
1892
1893         /* userspace might not need the counters */
1894         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1895                                         tmp.num_counters, tinfo.nentries);
1896         if (ret)
1897                 return ret;
1898
1899         pos = compat_ptr(tmp.entries);
1900         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1901                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1902 }
1903
1904 struct ebt_entries_buf_state {
1905         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1906         u32 buf_kern_len;       /* total size of kernel buffer */
1907         u32 buf_kern_offset;    /* amount of data copied so far */
1908         u32 buf_user_offset;    /* read position in userspace buffer */
1909 };
1910
1911 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1912 {
1913         state->buf_kern_offset += sz;
1914         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1915 }
1916
1917 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1918                        const void *data, unsigned int sz)
1919 {
1920         if (state->buf_kern_start == NULL)
1921                 goto count_only;
1922
1923         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1924                 return -EINVAL;
1925
1926         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1927
1928  count_only:
1929         state->buf_user_offset += sz;
1930         return ebt_buf_count(state, sz);
1931 }
1932
1933 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1934 {
1935         char *b = state->buf_kern_start;
1936
1937         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1938                 return -EINVAL;
1939
1940         if (b != NULL && sz > 0)
1941                 memset(b + state->buf_kern_offset, 0, sz);
1942         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1943         return ebt_buf_count(state, sz);
1944 }
1945
1946 enum compat_mwt {
1947         EBT_COMPAT_MATCH,
1948         EBT_COMPAT_WATCHER,
1949         EBT_COMPAT_TARGET,
1950 };
1951
1952 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1953                                 enum compat_mwt compat_mwt,
1954                                 struct ebt_entries_buf_state *state,
1955                                 const unsigned char *base)
1956 {
1957         char name[EBT_EXTENSION_MAXNAMELEN];
1958         struct xt_match *match;
1959         struct xt_target *wt;
1960         void *dst = NULL;
1961         int off, pad = 0;
1962         unsigned int size_kern, match_size = mwt->match_size;
1963
1964         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1965                 return -EINVAL;
1966
1967         if (state->buf_kern_start)
1968                 dst = state->buf_kern_start + state->buf_kern_offset;
1969
1970         switch (compat_mwt) {
1971         case EBT_COMPAT_MATCH:
1972                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1973                                               mwt->u.revision);
1974                 if (IS_ERR(match))
1975                         return PTR_ERR(match);
1976
1977                 off = ebt_compat_match_offset(match, match_size);
1978                 if (dst) {
1979                         if (match->compat_from_user)
1980                                 match->compat_from_user(dst, mwt->data);
1981                         else
1982                                 memcpy(dst, mwt->data, match_size);
1983                 }
1984
1985                 size_kern = match->matchsize;
1986                 if (unlikely(size_kern == -1))
1987                         size_kern = match_size;
1988                 module_put(match->me);
1989                 break;
1990         case EBT_COMPAT_WATCHER:
1991         case EBT_COMPAT_TARGET:
1992                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1993                                             mwt->u.revision);
1994                 if (IS_ERR(wt))
1995                         return PTR_ERR(wt);
1996                 off = xt_compat_target_offset(wt);
1997
1998                 if (dst) {
1999                         if (wt->compat_from_user)
2000                                 wt->compat_from_user(dst, mwt->data);
2001                         else
2002                                 memcpy(dst, mwt->data, match_size);
2003                 }
2004
2005                 size_kern = wt->targetsize;
2006                 module_put(wt->me);
2007                 break;
2008
2009         default:
2010                 return -EINVAL;
2011         }
2012
2013         state->buf_kern_offset += match_size + off;
2014         state->buf_user_offset += match_size;
2015         pad = XT_ALIGN(size_kern) - size_kern;
2016
2017         if (pad > 0 && dst) {
2018                 if (WARN_ON(state->buf_kern_len <= pad))
2019                         return -EINVAL;
2020                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2021                         return -EINVAL;
2022                 memset(dst + size_kern, 0, pad);
2023         }
2024         return off + match_size;
2025 }
2026
2027 /* return size of all matches, watchers or target, including necessary
2028  * alignment and padding.
2029  */
2030 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2031                         unsigned int size_left, enum compat_mwt type,
2032                         struct ebt_entries_buf_state *state, const void *base)
2033 {
2034         const char *buf = (const char *)match32;
2035         int growth = 0;
2036
2037         if (size_left == 0)
2038                 return 0;
2039
2040         do {
2041                 struct ebt_entry_match *match_kern;
2042                 int ret;
2043
2044                 if (size_left < sizeof(*match32))
2045                         return -EINVAL;
2046
2047                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2048                 if (match_kern) {
2049                         char *tmp;
2050                         tmp = state->buf_kern_start + state->buf_kern_offset;
2051                         match_kern = (struct ebt_entry_match *) tmp;
2052                 }
2053                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2054                 if (ret < 0)
2055                         return ret;
2056                 size_left -= sizeof(*match32);
2057
2058                 /* add padding before match->data (if any) */
2059                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2060                 if (ret < 0)
2061                         return ret;
2062
2063                 if (match32->match_size > size_left)
2064                         return -EINVAL;
2065
2066                 size_left -= match32->match_size;
2067
2068                 ret = compat_mtw_from_user(match32, type, state, base);
2069                 if (ret < 0)
2070                         return ret;
2071
2072                 if (WARN_ON(ret < match32->match_size))
2073                         return -EINVAL;
2074                 growth += ret - match32->match_size;
2075                 growth += ebt_compat_entry_padsize();
2076
2077                 buf += sizeof(*match32);
2078                 buf += match32->match_size;
2079
2080                 if (match_kern)
2081                         match_kern->match_size = ret;
2082
2083                 match32 = (struct compat_ebt_entry_mwt *) buf;
2084         } while (size_left);
2085
2086         return growth;
2087 }
2088
2089 /* called for all ebt_entry structures. */
2090 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2091                           unsigned int *total,
2092                           struct ebt_entries_buf_state *state)
2093 {
2094         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2095         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2096         unsigned int offsets[4];
2097         unsigned int *offsets_update = NULL;
2098         int ret;
2099         char *buf_start;
2100
2101         if (*total < sizeof(struct ebt_entries))
2102                 return -EINVAL;
2103
2104         if (!entry->bitmask) {
2105                 *total -= sizeof(struct ebt_entries);
2106                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2107         }
2108         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2109                 return -EINVAL;
2110
2111         startoff = state->buf_user_offset;
2112         /* pull in most part of ebt_entry, it does not need to be changed. */
2113         ret = ebt_buf_add(state, entry,
2114                         offsetof(struct ebt_entry, watchers_offset));
2115         if (ret < 0)
2116                 return ret;
2117
2118         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2119         memcpy(&offsets[1], &entry->watchers_offset,
2120                         sizeof(offsets) - sizeof(offsets[0]));
2121
2122         if (state->buf_kern_start) {
2123                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2124                 offsets_update = (unsigned int *) buf_start;
2125         }
2126         ret = ebt_buf_add(state, &offsets[1],
2127                         sizeof(offsets) - sizeof(offsets[0]));
2128         if (ret < 0)
2129                 return ret;
2130         buf_start = (char *) entry;
2131         /* 0: matches offset, always follows ebt_entry.
2132          * 1: watchers offset, from ebt_entry structure
2133          * 2: target offset, from ebt_entry structure
2134          * 3: next ebt_entry offset, from ebt_entry structure
2135          *
2136          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2137          */
2138         for (i = 0; i < 4 ; ++i) {
2139                 if (offsets[i] > *total)
2140                         return -EINVAL;
2141
2142                 if (i < 3 && offsets[i] == *total)
2143                         return -EINVAL;
2144
2145                 if (i == 0)
2146                         continue;
2147                 if (offsets[i-1] > offsets[i])
2148                         return -EINVAL;
2149         }
2150
2151         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2152                 struct compat_ebt_entry_mwt *match32;
2153                 unsigned int size;
2154                 char *buf = buf_start + offsets[i];
2155
2156                 if (offsets[i] > offsets[j])
2157                         return -EINVAL;
2158
2159                 match32 = (struct compat_ebt_entry_mwt *) buf;
2160                 size = offsets[j] - offsets[i];
2161                 ret = ebt_size_mwt(match32, size, i, state, base);
2162                 if (ret < 0)
2163                         return ret;
2164                 new_offset += ret;
2165                 if (offsets_update && new_offset) {
2166                         pr_debug("change offset %d to %d\n",
2167                                 offsets_update[i], offsets[j] + new_offset);
2168                         offsets_update[i] = offsets[j] + new_offset;
2169                 }
2170         }
2171
2172         if (state->buf_kern_start == NULL) {
2173                 unsigned int offset = buf_start - (char *) base;
2174
2175                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2176                 if (ret < 0)
2177                         return ret;
2178         }
2179
2180         next_expected_off = state->buf_user_offset - startoff;
2181         if (next_expected_off != entry->next_offset)
2182                 return -EINVAL;
2183
2184         if (*total < entry->next_offset)
2185                 return -EINVAL;
2186         *total -= entry->next_offset;
2187         return 0;
2188 }
2189
2190 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2191  * It might need more memory when copied to a 64 bit kernel in case
2192  * userspace is 32-bit. So, first task: find out how much memory is needed.
2193  *
2194  * Called before validation is performed.
2195  */
2196 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2197                                 struct ebt_entries_buf_state *state)
2198 {
2199         unsigned int size_remaining = size_user;
2200         int ret;
2201
2202         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2203                                         &size_remaining, state);
2204         if (ret < 0)
2205                 return ret;
2206
2207         if (size_remaining)
2208                 return -EINVAL;
2209
2210         return state->buf_kern_offset;
2211 }
2212
2213
2214 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2215                                              sockptr_t arg, unsigned int len)
2216 {
2217         struct compat_ebt_replace tmp;
2218         int i;
2219
2220         if (len < sizeof(tmp))
2221                 return -EINVAL;
2222
2223         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2224                 return -EFAULT;
2225
2226         if (len != sizeof(tmp) + tmp.entries_size)
2227                 return -EINVAL;
2228
2229         if (tmp.entries_size == 0)
2230                 return -EINVAL;
2231
2232         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2233                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2234                 return -ENOMEM;
2235         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2236                 return -ENOMEM;
2237
2238         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2239
2240         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2241         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2242                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2243
2244         repl->num_counters = tmp.num_counters;
2245         repl->counters = compat_ptr(tmp.counters);
2246         repl->entries = compat_ptr(tmp.entries);
2247         return 0;
2248 }
2249
2250 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2251 {
2252         int ret, i, countersize, size64;
2253         struct ebt_table_info *newinfo;
2254         struct ebt_replace tmp;
2255         struct ebt_entries_buf_state state;
2256         void *entries_tmp;
2257
2258         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2259         if (ret) {
2260                 /* try real handler in case userland supplied needed padding */
2261                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2262                         ret = 0;
2263                 return ret;
2264         }
2265
2266         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2267         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2268         if (!newinfo)
2269                 return -ENOMEM;
2270
2271         if (countersize)
2272                 memset(newinfo->counters, 0, countersize);
2273
2274         memset(&state, 0, sizeof(state));
2275
2276         newinfo->entries = vmalloc(tmp.entries_size);
2277         if (!newinfo->entries) {
2278                 ret = -ENOMEM;
2279                 goto free_newinfo;
2280         }
2281         if (copy_from_user(
2282            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2283                 ret = -EFAULT;
2284                 goto free_entries;
2285         }
2286
2287         entries_tmp = newinfo->entries;
2288
2289         xt_compat_lock(NFPROTO_BRIDGE);
2290
2291         ret = ebt_compat_init_offsets(tmp.nentries);
2292         if (ret < 0)
2293                 goto out_unlock;
2294
2295         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2296         if (ret < 0)
2297                 goto out_unlock;
2298
2299         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2300                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2301                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2302
2303         size64 = ret;
2304         newinfo->entries = vmalloc(size64);
2305         if (!newinfo->entries) {
2306                 vfree(entries_tmp);
2307                 ret = -ENOMEM;
2308                 goto out_unlock;
2309         }
2310
2311         memset(&state, 0, sizeof(state));
2312         state.buf_kern_start = newinfo->entries;
2313         state.buf_kern_len = size64;
2314
2315         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2316         if (WARN_ON(ret < 0)) {
2317                 vfree(entries_tmp);
2318                 goto out_unlock;
2319         }
2320
2321         vfree(entries_tmp);
2322         tmp.entries_size = size64;
2323
2324         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2325                 char __user *usrptr;
2326                 if (tmp.hook_entry[i]) {
2327                         unsigned int delta;
2328                         usrptr = (char __user *) tmp.hook_entry[i];
2329                         delta = usrptr - tmp.entries;
2330                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2331                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2332                 }
2333         }
2334
2335         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2336         xt_compat_unlock(NFPROTO_BRIDGE);
2337
2338         ret = do_replace_finish(net, &tmp, newinfo);
2339         if (ret == 0)
2340                 return ret;
2341 free_entries:
2342         vfree(newinfo->entries);
2343 free_newinfo:
2344         vfree(newinfo);
2345         return ret;
2346 out_unlock:
2347         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2348         xt_compat_unlock(NFPROTO_BRIDGE);
2349         goto free_entries;
2350 }
2351
2352 static int compat_update_counters(struct net *net, sockptr_t arg,
2353                                   unsigned int len)
2354 {
2355         struct compat_ebt_replace hlp;
2356
2357         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2358                 return -EFAULT;
2359
2360         /* try real handler in case userland supplied needed padding */
2361         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2362                 return update_counters(net, arg, len);
2363
2364         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2365                                   hlp.num_counters, len);
2366 }
2367
2368 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2369                 void __user *user, int *len)
2370 {
2371         int ret;
2372         struct compat_ebt_replace tmp;
2373         struct ebt_table *t;
2374         struct net *net = sock_net(sk);
2375
2376         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2377             *len != sizeof(struct compat_ebt_replace))
2378                 return -EINVAL;
2379
2380         if (copy_from_user(&tmp, user, sizeof(tmp)))
2381                 return -EFAULT;
2382
2383         tmp.name[sizeof(tmp.name) - 1] = '\0';
2384
2385         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2386         if (!t)
2387                 return ret;
2388
2389         xt_compat_lock(NFPROTO_BRIDGE);
2390         switch (cmd) {
2391         case EBT_SO_GET_INFO:
2392                 tmp.nentries = t->private->nentries;
2393                 ret = compat_table_info(t->private, &tmp);
2394                 if (ret)
2395                         goto out;
2396                 tmp.valid_hooks = t->valid_hooks;
2397
2398                 if (copy_to_user(user, &tmp, *len) != 0) {
2399                         ret = -EFAULT;
2400                         break;
2401                 }
2402                 ret = 0;
2403                 break;
2404         case EBT_SO_GET_INIT_INFO:
2405                 tmp.nentries = t->table->nentries;
2406                 tmp.entries_size = t->table->entries_size;
2407                 tmp.valid_hooks = t->table->valid_hooks;
2408
2409                 if (copy_to_user(user, &tmp, *len) != 0) {
2410                         ret = -EFAULT;
2411                         break;
2412                 }
2413                 ret = 0;
2414                 break;
2415         case EBT_SO_GET_ENTRIES:
2416         case EBT_SO_GET_INIT_ENTRIES:
2417                 /* try real handler first in case of userland-side padding.
2418                  * in case we are dealing with an 'ordinary' 32 bit binary
2419                  * without 64bit compatibility padding, this will fail right
2420                  * after copy_from_user when the *len argument is validated.
2421                  *
2422                  * the compat_ variant needs to do one pass over the kernel
2423                  * data set to adjust for size differences before it the check.
2424                  */
2425                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2426                         ret = 0;
2427                 else
2428                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2429                 break;
2430         default:
2431                 ret = -EINVAL;
2432         }
2433  out:
2434         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2435         xt_compat_unlock(NFPROTO_BRIDGE);
2436         mutex_unlock(&ebt_mutex);
2437         return ret;
2438 }
2439 #endif
2440
2441 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2442 {
2443         struct net *net = sock_net(sk);
2444         struct ebt_replace tmp;
2445         struct ebt_table *t;
2446         int ret;
2447
2448         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2449                 return -EPERM;
2450
2451 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2452         /* try real handler in case userland supplied needed padding */
2453         if (in_compat_syscall() &&
2454             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2455              *len != sizeof(tmp)))
2456                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2457 #endif
2458
2459         if (copy_from_user(&tmp, user, sizeof(tmp)))
2460                 return -EFAULT;
2461
2462         tmp.name[sizeof(tmp.name) - 1] = '\0';
2463
2464         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2465         if (!t)
2466                 return ret;
2467
2468         switch (cmd) {
2469         case EBT_SO_GET_INFO:
2470         case EBT_SO_GET_INIT_INFO:
2471                 if (*len != sizeof(struct ebt_replace)) {
2472                         ret = -EINVAL;
2473                         mutex_unlock(&ebt_mutex);
2474                         break;
2475                 }
2476                 if (cmd == EBT_SO_GET_INFO) {
2477                         tmp.nentries = t->private->nentries;
2478                         tmp.entries_size = t->private->entries_size;
2479                         tmp.valid_hooks = t->valid_hooks;
2480                 } else {
2481                         tmp.nentries = t->table->nentries;
2482                         tmp.entries_size = t->table->entries_size;
2483                         tmp.valid_hooks = t->table->valid_hooks;
2484                 }
2485                 mutex_unlock(&ebt_mutex);
2486                 if (copy_to_user(user, &tmp, *len) != 0) {
2487                         ret = -EFAULT;
2488                         break;
2489                 }
2490                 ret = 0;
2491                 break;
2492
2493         case EBT_SO_GET_ENTRIES:
2494         case EBT_SO_GET_INIT_ENTRIES:
2495                 ret = copy_everything_to_user(t, user, len, cmd);
2496                 mutex_unlock(&ebt_mutex);
2497                 break;
2498
2499         default:
2500                 mutex_unlock(&ebt_mutex);
2501                 ret = -EINVAL;
2502         }
2503
2504         return ret;
2505 }
2506
2507 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2508                 unsigned int len)
2509 {
2510         struct net *net = sock_net(sk);
2511         int ret;
2512
2513         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2514                 return -EPERM;
2515
2516         switch (cmd) {
2517         case EBT_SO_SET_ENTRIES:
2518 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2519                 if (in_compat_syscall())
2520                         ret = compat_do_replace(net, arg, len);
2521                 else
2522 #endif
2523                         ret = do_replace(net, arg, len);
2524                 break;
2525         case EBT_SO_SET_COUNTERS:
2526 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2527                 if (in_compat_syscall())
2528                         ret = compat_update_counters(net, arg, len);
2529                 else
2530 #endif
2531                         ret = update_counters(net, arg, len);
2532                 break;
2533         default:
2534                 ret = -EINVAL;
2535         }
2536         return ret;
2537 }
2538
2539 static struct nf_sockopt_ops ebt_sockopts = {
2540         .pf             = PF_INET,
2541         .set_optmin     = EBT_BASE_CTL,
2542         .set_optmax     = EBT_SO_SET_MAX + 1,
2543         .set            = do_ebt_set_ctl,
2544         .get_optmin     = EBT_BASE_CTL,
2545         .get_optmax     = EBT_SO_GET_MAX + 1,
2546         .get            = do_ebt_get_ctl,
2547         .owner          = THIS_MODULE,
2548 };
2549
2550 static int __net_init ebt_pernet_init(struct net *net)
2551 {
2552         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2553
2554         INIT_LIST_HEAD(&ebt_net->tables);
2555         return 0;
2556 }
2557
2558 static struct pernet_operations ebt_net_ops = {
2559         .init = ebt_pernet_init,
2560         .id   = &ebt_pernet_id,
2561         .size = sizeof(struct ebt_pernet),
2562 };
2563
2564 static int __init ebtables_init(void)
2565 {
2566         int ret;
2567
2568         ret = xt_register_target(&ebt_standard_target);
2569         if (ret < 0)
2570                 return ret;
2571         ret = nf_register_sockopt(&ebt_sockopts);
2572         if (ret < 0) {
2573                 xt_unregister_target(&ebt_standard_target);
2574                 return ret;
2575         }
2576
2577         ret = register_pernet_subsys(&ebt_net_ops);
2578         if (ret < 0) {
2579                 nf_unregister_sockopt(&ebt_sockopts);
2580                 xt_unregister_target(&ebt_standard_target);
2581                 return ret;
2582         }
2583
2584         return 0;
2585 }
2586
2587 static void ebtables_fini(void)
2588 {
2589         nf_unregister_sockopt(&ebt_sockopts);
2590         xt_unregister_target(&ebt_standard_target);
2591         unregister_pernet_subsys(&ebt_net_ops);
2592 }
2593
2594 EXPORT_SYMBOL(ebt_register_table);
2595 EXPORT_SYMBOL(ebt_unregister_table);
2596 EXPORT_SYMBOL(ebt_do_table);
2597 module_init(ebtables_init);
2598 module_exit(ebtables_fini);
2599 MODULE_LICENSE("GPL");