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_node(array_size(udc_cnt,
 930                                           sizeof(*(newinfo->chainstack[0]))),
 931                                        cpu_to_node(i));
 932                         if (!newinfo->chainstack[i]) {
 933                                 while (i)
 934                                         vfree(newinfo->chainstack[--i]);
 935                                 vfree(newinfo->chainstack);
 936                                 newinfo->chainstack = NULL;
 937                                 return -ENOMEM;
 938                         }
 939                 }
 940
 941                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 942                 if (!cl_s)
 943                         return -ENOMEM;
 944                 i = 0; /* the i'th udc */
 945                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 946                    ebt_get_udc_positions, newinfo, &i, cl_s);
 947                 /* sanity check */
 948                 if (i != udc_cnt) {
 949                         vfree(cl_s);
 950                         return -EFAULT;
 951                 }
 952         }
 953
 954         /* Check for loops */
 955         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 956                 if (newinfo->hook_entry[i])
 957                         if (check_chainloops(newinfo->hook_entry[i],
 958                            cl_s, udc_cnt, i, newinfo->entries)) {
 959                                 vfree(cl_s);
 960                                 return -EINVAL;
 961                         }
 962
 963         /* we now know the following (along with E=mc²):
 964          *  - the nr of entries in each chain is right
 965          *  - the size of the allocated space is right
 966          *  - all valid hooks have a corresponding chain
 967          *  - there are no loops
 968          *  - wrong data can still be on the level of a single entry
 969          *  - could be there are jumps to places that are not the
 970          *    beginning of a chain. This can only occur in chains that
 971          *    are not accessible from any base chains, so we don't care.
 972          */
 973
 974         /* used to know what we need to clean up if something goes wrong */
 975         i = 0;
 976         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 977            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 978         if (ret != 0) {
 979                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 980                                   ebt_cleanup_entry, net, &i);
 981         }
 982         vfree(cl_s);
 983         return ret;
 984 }
 985
 986 /* called under write_lock */
 987 static void get_counters(const struct ebt_counter *oldcounters,
 988                          struct ebt_counter *counters, unsigned int nentries)
 989 {
 990         int i, cpu;
 991         struct ebt_counter *counter_base;
 992
 993         /* counters of cpu 0 */
 994         memcpy(counters, oldcounters,
 995                sizeof(struct ebt_counter) * nentries);
 996
 997         /* add other counters to those of cpu 0 */
 998         for_each_possible_cpu(cpu) {
 999                 if (cpu == 0)
1000                         continue;
1001                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
1002                 for (i = 0; i < nentries; i++)
1003                         ADD_COUNTER(counters[i], counter_base[i].bcnt,
1004                                     counter_base[i].pcnt);
1005         }
1006 }
1007
1008 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1009                               struct ebt_table_info *newinfo)
1010 {
1011         int ret;
1012         struct ebt_counter *counterstmp = NULL;
1013         /* used to be able to unlock earlier */
1014         struct ebt_table_info *table;
1015         struct ebt_table *t;
1016
1017         /* the user wants counters back
1018          * the check on the size is done later, when we have the lock
1019          */
1020         if (repl->num_counters) {
1021                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1022                 counterstmp = vmalloc(size);
1023                 if (!counterstmp)
1024                         return -ENOMEM;
1025         }
1026
1027         newinfo->chainstack = NULL;
1028         ret = ebt_verify_pointers(repl, newinfo);
1029         if (ret != 0)
1030                 goto free_counterstmp;
1031
1032         ret = translate_table(net, repl->name, newinfo);
1033
1034         if (ret != 0)
1035                 goto free_counterstmp;
1036
1037         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1038         if (!t) {
1039                 ret = -ENOENT;
1040                 goto free_iterate;
1041         }
1042
1043         /* the table doesn't like it */
1044         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1045                 goto free_unlock;
1046
1047         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1048                 ret = -EINVAL;
1049                 goto free_unlock;
1050         }
1051
1052         /* we have the mutex lock, so no danger in reading this pointer */
1053         table = t->private;
1054         /* make sure the table can only be rmmod'ed if it contains no rules */
1055         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1056                 ret = -ENOENT;
1057                 goto free_unlock;
1058         } else if (table->nentries && !newinfo->nentries)
1059                 module_put(t->me);
1060         /* we need an atomic snapshot of the counters */
1061         write_lock_bh(&t->lock);
1062         if (repl->num_counters)
1063                 get_counters(t->private->counters, counterstmp,
1064                    t->private->nentries);
1065
1066         t->private = newinfo;
1067         write_unlock_bh(&t->lock);
1068         mutex_unlock(&ebt_mutex);
1069         /* so, a user can change the chains while having messed up her counter
1070          * allocation. Only reason why this is done is because this way the lock
1071          * is held only once, while this doesn't bring the kernel into a
1072          * dangerous state.
1073          */
1074         if (repl->num_counters &&
1075            copy_to_user(repl->counters, counterstmp,
1076            repl->num_counters * sizeof(struct ebt_counter))) {
1077                 /* Silent error, can't fail, new table is already in place */
1078                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1079         }
1080
1081         /* decrease module count and free resources */
1082         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1083                           ebt_cleanup_entry, net, NULL);
1084
1085         vfree(table->entries);
1086         ebt_free_table_info(table);
1087         vfree(table);
1088         vfree(counterstmp);
1089
1090         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1091                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1092         return ret;
1093
1094 free_unlock:
1095         mutex_unlock(&ebt_mutex);
1096 free_iterate:
1097         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1098                           ebt_cleanup_entry, net, NULL);
1099 free_counterstmp:
1100         vfree(counterstmp);
1101         /* can be initialized in translate_table() */
1102         ebt_free_table_info(newinfo);
1103         return ret;
1104 }
1105
1106 /* replace the table */
1107 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1108 {
1109         int ret, countersize;
1110         struct ebt_table_info *newinfo;
1111         struct ebt_replace tmp;
1112
1113         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1114                 return -EFAULT;
1115
1116         if (len != sizeof(tmp) + tmp.entries_size)
1117                 return -EINVAL;
1118
1119         if (tmp.entries_size == 0)
1120                 return -EINVAL;
1121
1122         /* overflow check */
1123         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1124                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1125                 return -ENOMEM;
1126         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1127                 return -ENOMEM;
1128
1129         tmp.name[sizeof(tmp.name) - 1] = 0;
1130
1131         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1132         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1133         if (!newinfo)
1134                 return -ENOMEM;
1135
1136         if (countersize)
1137                 memset(newinfo->counters, 0, countersize);
1138
1139         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1140         if (!newinfo->entries) {
1141                 ret = -ENOMEM;
1142                 goto free_newinfo;
1143         }
1144         if (copy_from_user(
1145            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1146                 ret = -EFAULT;
1147                 goto free_entries;
1148         }
1149
1150         ret = do_replace_finish(net, &tmp, newinfo);
1151         if (ret == 0)
1152                 return ret;
1153 free_entries:
1154         vfree(newinfo->entries);
1155 free_newinfo:
1156         vfree(newinfo);
1157         return ret;
1158 }
1159
1160 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1161 {
1162         mutex_lock(&ebt_mutex);
1163         list_del(&table->list);
1164         mutex_unlock(&ebt_mutex);
1165         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1166                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1167         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1168                           ebt_cleanup_entry, net, NULL);
1169         if (table->private->nentries)
1170                 module_put(table->me);
1171         vfree(table->private->entries);
1172         ebt_free_table_info(table->private);
1173         vfree(table->private);
1174         kfree(table->ops);
1175         kfree(table);
1176 }
1177
1178 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1179                        const struct nf_hook_ops *template_ops)
1180 {
1181         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1182         struct ebt_table_info *newinfo;
1183         struct ebt_table *t, *table;
1184         struct nf_hook_ops *ops;
1185         unsigned int num_ops;
1186         struct ebt_replace_kernel *repl;
1187         int ret, i, countersize;
1188         void *p;
1189
1190         if (input_table == NULL || (repl = input_table->table) == NULL ||
1191             repl->entries == NULL || repl->entries_size == 0 ||
1192             repl->counters != NULL || input_table->private != NULL)
1193                 return -EINVAL;
1194
1195         /* Don't add one table to multiple lists. */
1196         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1197         if (!table) {
1198                 ret = -ENOMEM;
1199                 goto out;
1200         }
1201
1202         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1203         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1204         ret = -ENOMEM;
1205         if (!newinfo)
1206                 goto free_table;
1207
1208         p = vmalloc(repl->entries_size);
1209         if (!p)
1210                 goto free_newinfo;
1211
1212         memcpy(p, repl->entries, repl->entries_size);
1213         newinfo->entries = p;
1214
1215         newinfo->entries_size = repl->entries_size;
1216         newinfo->nentries = repl->nentries;
1217
1218         if (countersize)
1219                 memset(newinfo->counters, 0, countersize);
1220
1221         /* fill in newinfo and parse the entries */
1222         newinfo->chainstack = NULL;
1223         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1224                 if ((repl->valid_hooks & (1 << i)) == 0)
1225                         newinfo->hook_entry[i] = NULL;
1226                 else
1227                         newinfo->hook_entry[i] = p +
1228                                 ((char *)repl->hook_entry[i] - repl->entries);
1229         }
1230         ret = translate_table(net, repl->name, newinfo);
1231         if (ret != 0)
1232                 goto free_chainstack;
1233
1234         if (table->check && table->check(newinfo, table->valid_hooks)) {
1235                 ret = -EINVAL;
1236                 goto free_chainstack;
1237         }
1238
1239         table->private = newinfo;
1240         rwlock_init(&table->lock);
1241         mutex_lock(&ebt_mutex);
1242         list_for_each_entry(t, &ebt_net->tables, list) {
1243                 if (strcmp(t->name, table->name) == 0) {
1244                         ret = -EEXIST;
1245                         goto free_unlock;
1246                 }
1247         }
1248
1249         /* Hold a reference count if the chains aren't empty */
1250         if (newinfo->nentries && !try_module_get(table->me)) {
1251                 ret = -ENOENT;
1252                 goto free_unlock;
1253         }
1254
1255         num_ops = hweight32(table->valid_hooks);
1256         if (num_ops == 0) {
1257                 ret = -EINVAL;
1258                 goto free_unlock;
1259         }
1260
1261         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1262         if (!ops) {
1263                 ret = -ENOMEM;
1264                 if (newinfo->nentries)
1265                         module_put(table->me);
1266                 goto free_unlock;
1267         }
1268
1269         for (i = 0; i < num_ops; i++)
1270                 ops[i].priv = table;
1271
1272         list_add(&table->list, &ebt_net->tables);
1273         mutex_unlock(&ebt_mutex);
1274
1275         table->ops = ops;
1276         ret = nf_register_net_hooks(net, ops, num_ops);
1277         if (ret)
1278                 __ebt_unregister_table(net, table);
1279
1280         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1281                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1282         return ret;
1283 free_unlock:
1284         mutex_unlock(&ebt_mutex);
1285 free_chainstack:
1286         ebt_free_table_info(newinfo);
1287         vfree(newinfo->entries);
1288 free_newinfo:
1289         vfree(newinfo);
1290 free_table:
1291         kfree(table);
1292 out:
1293         return ret;
1294 }
1295
1296 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1297 {
1298         struct ebt_template *tmpl;
1299
1300         mutex_lock(&ebt_mutex);
1301         list_for_each_entry(tmpl, &template_tables, list) {
1302                 if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1303                         mutex_unlock(&ebt_mutex);
1304                         return -EEXIST;
1305                 }
1306         }
1307
1308         tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1309         if (!tmpl) {
1310                 mutex_unlock(&ebt_mutex);
1311                 return -ENOMEM;
1312         }
1313
1314         tmpl->table_init = table_init;
1315         strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1316         tmpl->owner = t->me;
1317         list_add(&tmpl->list, &template_tables);
1318
1319         mutex_unlock(&ebt_mutex);
1320         return 0;
1321 }
1322 EXPORT_SYMBOL(ebt_register_template);
1323
1324 void ebt_unregister_template(const struct ebt_table *t)
1325 {
1326         struct ebt_template *tmpl;
1327
1328         mutex_lock(&ebt_mutex);
1329         list_for_each_entry(tmpl, &template_tables, list) {
1330                 if (strcmp(t->name, tmpl->name))
1331                         continue;
1332
1333                 list_del(&tmpl->list);
1334                 mutex_unlock(&ebt_mutex);
1335                 kfree(tmpl);
1336                 return;
1337         }
1338
1339         mutex_unlock(&ebt_mutex);
1340         WARN_ON_ONCE(1);
1341 }
1342 EXPORT_SYMBOL(ebt_unregister_template);
1343
1344 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1345 {
1346         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1347         struct ebt_table *t;
1348
1349         mutex_lock(&ebt_mutex);
1350
1351         list_for_each_entry(t, &ebt_net->tables, list) {
1352                 if (strcmp(t->name, name) == 0) {
1353                         mutex_unlock(&ebt_mutex);
1354                         return t;
1355                 }
1356         }
1357
1358         mutex_unlock(&ebt_mutex);
1359         return NULL;
1360 }
1361
1362 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1363 {
1364         struct ebt_table *table = __ebt_find_table(net, name);
1365
1366         if (table)
1367                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1368 }
1369 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1370
1371 void ebt_unregister_table(struct net *net, const char *name)
1372 {
1373         struct ebt_table *table = __ebt_find_table(net, name);
1374
1375         if (table)
1376                 __ebt_unregister_table(net, table);
1377 }
1378
1379 /* userspace just supplied us with counters */
1380 static int do_update_counters(struct net *net, const char *name,
1381                               struct ebt_counter __user *counters,
1382                               unsigned int num_counters, unsigned int len)
1383 {
1384         int i, ret;
1385         struct ebt_counter *tmp;
1386         struct ebt_table *t;
1387
1388         if (num_counters == 0)
1389                 return -EINVAL;
1390
1391         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1392         if (!tmp)
1393                 return -ENOMEM;
1394
1395         t = find_table_lock(net, name, &ret, &ebt_mutex);
1396         if (!t)
1397                 goto free_tmp;
1398
1399         if (num_counters != t->private->nentries) {
1400                 ret = -EINVAL;
1401                 goto unlock_mutex;
1402         }
1403
1404         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1405                 ret = -EFAULT;
1406                 goto unlock_mutex;
1407         }
1408
1409         /* we want an atomic add of the counters */
1410         write_lock_bh(&t->lock);
1411
1412         /* we add to the counters of the first cpu */
1413         for (i = 0; i < num_counters; i++)
1414                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1415
1416         write_unlock_bh(&t->lock);
1417         ret = 0;
1418 unlock_mutex:
1419         mutex_unlock(&ebt_mutex);
1420 free_tmp:
1421         vfree(tmp);
1422         return ret;
1423 }
1424
1425 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1426 {
1427         struct ebt_replace hlp;
1428
1429         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1430                 return -EFAULT;
1431
1432         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1433                 return -EINVAL;
1434
1435         return do_update_counters(net, hlp.name, hlp.counters,
1436                                   hlp.num_counters, len);
1437 }
1438
1439 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1440                                   const char *data, int entrysize,
1441                                   int usersize, int datasize, u8 revision)
1442 {
1443         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1444
1445         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1446          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1447          */
1448         strlcpy(name, _name, sizeof(name));
1449         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1450             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1451             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1452             xt_data_to_user(um + entrysize, data, usersize, datasize,
1453                             XT_ALIGN(datasize)))
1454                 return -EFAULT;
1455
1456         return 0;
1457 }
1458
1459 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1460                                     const char *base, char __user *ubase)
1461 {
1462         return ebt_obj_to_user(ubase + ((char *)m - base),
1463                                m->u.match->name, m->data, sizeof(*m),
1464                                m->u.match->usersize, m->match_size,
1465                                m->u.match->revision);
1466 }
1467
1468 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1469                                       const char *base, char __user *ubase)
1470 {
1471         return ebt_obj_to_user(ubase + ((char *)w - base),
1472                                w->u.watcher->name, w->data, sizeof(*w),
1473                                w->u.watcher->usersize, w->watcher_size,
1474                                w->u.watcher->revision);
1475 }
1476
1477 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1478                                     char __user *ubase)
1479 {
1480         int ret;
1481         char __user *hlp;
1482         const struct ebt_entry_target *t;
1483
1484         if (e->bitmask == 0) {
1485                 /* special case !EBT_ENTRY_OR_ENTRIES */
1486                 if (copy_to_user(ubase + ((char *)e - base), e,
1487                                  sizeof(struct ebt_entries)))
1488                         return -EFAULT;
1489                 return 0;
1490         }
1491
1492         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1493                 return -EFAULT;
1494
1495         hlp = ubase + (((char *)e + e->target_offset) - base);
1496         t = ebt_get_target_c(e);
1497
1498         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1499         if (ret != 0)
1500                 return ret;
1501         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1502         if (ret != 0)
1503                 return ret;
1504         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1505                               t->u.target->usersize, t->target_size,
1506                               t->u.target->revision);
1507         if (ret != 0)
1508                 return ret;
1509
1510         return 0;
1511 }
1512
1513 static int copy_counters_to_user(struct ebt_table *t,
1514                                  const struct ebt_counter *oldcounters,
1515                                  void __user *user, unsigned int num_counters,
1516                                  unsigned int nentries)
1517 {
1518         struct ebt_counter *counterstmp;
1519         int ret = 0;
1520
1521         /* userspace might not need the counters */
1522         if (num_counters == 0)
1523                 return 0;
1524
1525         if (num_counters != nentries)
1526                 return -EINVAL;
1527
1528         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1529         if (!counterstmp)
1530                 return -ENOMEM;
1531
1532         write_lock_bh(&t->lock);
1533         get_counters(oldcounters, counterstmp, nentries);
1534         write_unlock_bh(&t->lock);
1535
1536         if (copy_to_user(user, counterstmp,
1537            nentries * sizeof(struct ebt_counter)))
1538                 ret = -EFAULT;
1539         vfree(counterstmp);
1540         return ret;
1541 }
1542
1543 /* called with ebt_mutex locked */
1544 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1545                                    const int *len, int cmd)
1546 {
1547         struct ebt_replace tmp;
1548         const struct ebt_counter *oldcounters;
1549         unsigned int entries_size, nentries;
1550         int ret;
1551         char *entries;
1552
1553         if (cmd == EBT_SO_GET_ENTRIES) {
1554                 entries_size = t->private->entries_size;
1555                 nentries = t->private->nentries;
1556                 entries = t->private->entries;
1557                 oldcounters = t->private->counters;
1558         } else {
1559                 entries_size = t->table->entries_size;
1560                 nentries = t->table->nentries;
1561                 entries = t->table->entries;
1562                 oldcounters = t->table->counters;
1563         }
1564
1565         if (copy_from_user(&tmp, user, sizeof(tmp)))
1566                 return -EFAULT;
1567
1568         if (*len != sizeof(struct ebt_replace) + entries_size +
1569            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1570                 return -EINVAL;
1571
1572         if (tmp.nentries != nentries)
1573                 return -EINVAL;
1574
1575         if (tmp.entries_size != entries_size)
1576                 return -EINVAL;
1577
1578         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1579                                         tmp.num_counters, nentries);
1580         if (ret)
1581                 return ret;
1582
1583         /* set the match/watcher/target names right */
1584         return EBT_ENTRY_ITERATE(entries, entries_size,
1585            ebt_entry_to_user, entries, tmp.entries);
1586 }
1587
1588 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1589 /* 32 bit-userspace compatibility definitions. */
1590 struct compat_ebt_replace {
1591         char name[EBT_TABLE_MAXNAMELEN];
1592         compat_uint_t valid_hooks;
1593         compat_uint_t nentries;
1594         compat_uint_t entries_size;
1595         /* start of the chains */
1596         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1597         /* nr of counters userspace expects back */
1598         compat_uint_t num_counters;
1599         /* where the kernel will put the old counters. */
1600         compat_uptr_t counters;
1601         compat_uptr_t entries;
1602 };
1603
1604 /* struct ebt_entry_match, _target and _watcher have same layout */
1605 struct compat_ebt_entry_mwt {
1606         union {
1607                 struct {
1608                         char name[EBT_EXTENSION_MAXNAMELEN];
1609                         u8 revision;
1610                 };
1611                 compat_uptr_t ptr;
1612         } u;
1613         compat_uint_t match_size;
1614         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1615 };
1616
1617 /* account for possible padding between match_size and ->data */
1618 static int ebt_compat_entry_padsize(void)
1619 {
1620         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1621                         sizeof(struct compat_ebt_entry_mwt));
1622         return (int) sizeof(struct ebt_entry_match) -
1623                         sizeof(struct compat_ebt_entry_mwt);
1624 }
1625
1626 static int ebt_compat_match_offset(const struct xt_match *match,
1627                                    unsigned int userlen)
1628 {
1629         /* ebt_among needs special handling. The kernel .matchsize is
1630          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1631          * value is expected.
1632          * Example: userspace sends 4500, ebt_among.c wants 4504.
1633          */
1634         if (unlikely(match->matchsize == -1))
1635                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1636         return xt_compat_match_offset(match);
1637 }
1638
1639 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1640                                 unsigned int *size)
1641 {
1642         const struct xt_match *match = m->u.match;
1643         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1644         int off = ebt_compat_match_offset(match, m->match_size);
1645         compat_uint_t msize = m->match_size - off;
1646
1647         if (WARN_ON(off >= m->match_size))
1648                 return -EINVAL;
1649
1650         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1651             put_user(match->revision, &cm->u.revision) ||
1652             put_user(msize, &cm->match_size))
1653                 return -EFAULT;
1654
1655         if (match->compat_to_user) {
1656                 if (match->compat_to_user(cm->data, m->data))
1657                         return -EFAULT;
1658         } else {
1659                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1660                                     COMPAT_XT_ALIGN(msize)))
1661                         return -EFAULT;
1662         }
1663
1664         *size -= ebt_compat_entry_padsize() + off;
1665         *dstptr = cm->data;
1666         *dstptr += msize;
1667         return 0;
1668 }
1669
1670 static int compat_target_to_user(struct ebt_entry_target *t,
1671                                  void __user **dstptr,
1672                                  unsigned int *size)
1673 {
1674         const struct xt_target *target = t->u.target;
1675         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1676         int off = xt_compat_target_offset(target);
1677         compat_uint_t tsize = t->target_size - off;
1678
1679         if (WARN_ON(off >= t->target_size))
1680                 return -EINVAL;
1681
1682         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1683             put_user(target->revision, &cm->u.revision) ||
1684             put_user(tsize, &cm->match_size))
1685                 return -EFAULT;
1686
1687         if (target->compat_to_user) {
1688                 if (target->compat_to_user(cm->data, t->data))
1689                         return -EFAULT;
1690         } else {
1691                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1692                                     COMPAT_XT_ALIGN(tsize)))
1693                         return -EFAULT;
1694         }
1695
1696         *size -= ebt_compat_entry_padsize() + off;
1697         *dstptr = cm->data;
1698         *dstptr += tsize;
1699         return 0;
1700 }
1701
1702 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1703                                   void __user **dstptr,
1704                                   unsigned int *size)
1705 {
1706         return compat_target_to_user((struct ebt_entry_target *)w,
1707                                                         dstptr, size);
1708 }
1709
1710 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1711                                 unsigned int *size)
1712 {
1713         struct ebt_entry_target *t;
1714         struct ebt_entry __user *ce;
1715         u32 watchers_offset, target_offset, next_offset;
1716         compat_uint_t origsize;
1717         int ret;
1718
1719         if (e->bitmask == 0) {
1720                 if (*size < sizeof(struct ebt_entries))
1721                         return -EINVAL;
1722                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1723                         return -EFAULT;
1724
1725                 *dstptr += sizeof(struct ebt_entries);
1726                 *size -= sizeof(struct ebt_entries);
1727                 return 0;
1728         }
1729
1730         if (*size < sizeof(*ce))
1731                 return -EINVAL;
1732
1733         ce = *dstptr;
1734         if (copy_to_user(ce, e, sizeof(*ce)))
1735                 return -EFAULT;
1736
1737         origsize = *size;
1738         *dstptr += sizeof(*ce);
1739
1740         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1741         if (ret)
1742                 return ret;
1743         watchers_offset = e->watchers_offset - (origsize - *size);
1744
1745         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1746         if (ret)
1747                 return ret;
1748         target_offset = e->target_offset - (origsize - *size);
1749
1750         t = ebt_get_target(e);
1751
1752         ret = compat_target_to_user(t, dstptr, size);
1753         if (ret)
1754                 return ret;
1755         next_offset = e->next_offset - (origsize - *size);
1756
1757         if (put_user(watchers_offset, &ce->watchers_offset) ||
1758             put_user(target_offset, &ce->target_offset) ||
1759             put_user(next_offset, &ce->next_offset))
1760                 return -EFAULT;
1761
1762         *size -= sizeof(*ce);
1763         return 0;
1764 }
1765
1766 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1767 {
1768         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1769         *off += ebt_compat_entry_padsize();
1770         return 0;
1771 }
1772
1773 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1774 {
1775         *off += xt_compat_target_offset(w->u.watcher);
1776         *off += ebt_compat_entry_padsize();
1777         return 0;
1778 }
1779
1780 static int compat_calc_entry(const struct ebt_entry *e,
1781                              const struct ebt_table_info *info,
1782                              const void *base,
1783                              struct compat_ebt_replace *newinfo)
1784 {
1785         const struct ebt_entry_target *t;
1786         unsigned int entry_offset;
1787         int off, ret, i;
1788
1789         if (e->bitmask == 0)
1790                 return 0;
1791
1792         off = 0;
1793         entry_offset = (void *)e - base;
1794
1795         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1796         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1797
1798         t = ebt_get_target_c(e);
1799
1800         off += xt_compat_target_offset(t->u.target);
1801         off += ebt_compat_entry_padsize();
1802
1803         newinfo->entries_size -= off;
1804
1805         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1806         if (ret)
1807                 return ret;
1808
1809         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1810                 const void *hookptr = info->hook_entry[i];
1811                 if (info->hook_entry[i] &&
1812                     (e < (struct ebt_entry *)(base - hookptr))) {
1813                         newinfo->hook_entry[i] -= off;
1814                         pr_debug("0x%08X -> 0x%08X\n",
1815                                         newinfo->hook_entry[i] + off,
1816                                         newinfo->hook_entry[i]);
1817                 }
1818         }
1819
1820         return 0;
1821 }
1822
1823 static int ebt_compat_init_offsets(unsigned int number)
1824 {
1825         if (number > INT_MAX)
1826                 return -EINVAL;
1827
1828         /* also count the base chain policies */
1829         number += NF_BR_NUMHOOKS;
1830
1831         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1832 }
1833
1834 static int compat_table_info(const struct ebt_table_info *info,
1835                              struct compat_ebt_replace *newinfo)
1836 {
1837         unsigned int size = info->entries_size;
1838         const void *entries = info->entries;
1839         int ret;
1840
1841         newinfo->entries_size = size;
1842         ret = ebt_compat_init_offsets(info->nentries);
1843         if (ret)
1844                 return ret;
1845
1846         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1847                                                         entries, newinfo);
1848 }
1849
1850 static int compat_copy_everything_to_user(struct ebt_table *t,
1851                                           void __user *user, int *len, int cmd)
1852 {
1853         struct compat_ebt_replace repl, tmp;
1854         struct ebt_counter *oldcounters;
1855         struct ebt_table_info tinfo;
1856         int ret;
1857         void __user *pos;
1858
1859         memset(&tinfo, 0, sizeof(tinfo));
1860
1861         if (cmd == EBT_SO_GET_ENTRIES) {
1862                 tinfo.entries_size = t->private->entries_size;
1863                 tinfo.nentries = t->private->nentries;
1864                 tinfo.entries = t->private->entries;
1865                 oldcounters = t->private->counters;
1866         } else {
1867                 tinfo.entries_size = t->table->entries_size;
1868                 tinfo.nentries = t->table->nentries;
1869                 tinfo.entries = t->table->entries;
1870                 oldcounters = t->table->counters;
1871         }
1872
1873         if (copy_from_user(&tmp, user, sizeof(tmp)))
1874                 return -EFAULT;
1875
1876         if (tmp.nentries != tinfo.nentries ||
1877            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1878                 return -EINVAL;
1879
1880         memcpy(&repl, &tmp, sizeof(repl));
1881         if (cmd == EBT_SO_GET_ENTRIES)
1882                 ret = compat_table_info(t->private, &repl);
1883         else
1884                 ret = compat_table_info(&tinfo, &repl);
1885         if (ret)
1886                 return ret;
1887
1888         if (*len != sizeof(tmp) + repl.entries_size +
1889            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1890                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1891                                 *len, tinfo.entries_size, repl.entries_size);
1892                 return -EINVAL;
1893         }
1894
1895         /* userspace might not need the counters */
1896         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1897                                         tmp.num_counters, tinfo.nentries);
1898         if (ret)
1899                 return ret;
1900
1901         pos = compat_ptr(tmp.entries);
1902         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1903                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1904 }
1905
1906 struct ebt_entries_buf_state {
1907         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1908         u32 buf_kern_len;       /* total size of kernel buffer */
1909         u32 buf_kern_offset;    /* amount of data copied so far */
1910         u32 buf_user_offset;    /* read position in userspace buffer */
1911 };
1912
1913 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1914 {
1915         state->buf_kern_offset += sz;
1916         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1917 }
1918
1919 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1920                        const void *data, unsigned int sz)
1921 {
1922         if (state->buf_kern_start == NULL)
1923                 goto count_only;
1924
1925         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1926                 return -EINVAL;
1927
1928         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1929
1930  count_only:
1931         state->buf_user_offset += sz;
1932         return ebt_buf_count(state, sz);
1933 }
1934
1935 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1936 {
1937         char *b = state->buf_kern_start;
1938
1939         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1940                 return -EINVAL;
1941
1942         if (b != NULL && sz > 0)
1943                 memset(b + state->buf_kern_offset, 0, sz);
1944         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1945         return ebt_buf_count(state, sz);
1946 }
1947
1948 enum compat_mwt {
1949         EBT_COMPAT_MATCH,
1950         EBT_COMPAT_WATCHER,
1951         EBT_COMPAT_TARGET,
1952 };
1953
1954 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1955                                 enum compat_mwt compat_mwt,
1956                                 struct ebt_entries_buf_state *state,
1957                                 const unsigned char *base)
1958 {
1959         char name[EBT_EXTENSION_MAXNAMELEN];
1960         struct xt_match *match;
1961         struct xt_target *wt;
1962         void *dst = NULL;
1963         int off, pad = 0;
1964         unsigned int size_kern, match_size = mwt->match_size;
1965
1966         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1967                 return -EINVAL;
1968
1969         if (state->buf_kern_start)
1970                 dst = state->buf_kern_start + state->buf_kern_offset;
1971
1972         switch (compat_mwt) {
1973         case EBT_COMPAT_MATCH:
1974                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1975                                               mwt->u.revision);
1976                 if (IS_ERR(match))
1977                         return PTR_ERR(match);
1978
1979                 off = ebt_compat_match_offset(match, match_size);
1980                 if (dst) {
1981                         if (match->compat_from_user)
1982                                 match->compat_from_user(dst, mwt->data);
1983                         else
1984                                 memcpy(dst, mwt->data, match_size);
1985                 }
1986
1987                 size_kern = match->matchsize;
1988                 if (unlikely(size_kern == -1))
1989                         size_kern = match_size;
1990                 module_put(match->me);
1991                 break;
1992         case EBT_COMPAT_WATCHER:
1993         case EBT_COMPAT_TARGET:
1994                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1995                                             mwt->u.revision);
1996                 if (IS_ERR(wt))
1997                         return PTR_ERR(wt);
1998                 off = xt_compat_target_offset(wt);
1999
2000                 if (dst) {
2001                         if (wt->compat_from_user)
2002                                 wt->compat_from_user(dst, mwt->data);
2003                         else
2004                                 memcpy(dst, mwt->data, match_size);
2005                 }
2006
2007                 size_kern = wt->targetsize;
2008                 module_put(wt->me);
2009                 break;
2010
2011         default:
2012                 return -EINVAL;
2013         }
2014
2015         state->buf_kern_offset += match_size + off;
2016         state->buf_user_offset += match_size;
2017         pad = XT_ALIGN(size_kern) - size_kern;
2018
2019         if (pad > 0 && dst) {
2020                 if (WARN_ON(state->buf_kern_len <= pad))
2021                         return -EINVAL;
2022                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2023                         return -EINVAL;
2024                 memset(dst + size_kern, 0, pad);
2025         }
2026         return off + match_size;
2027 }
2028
2029 /* return size of all matches, watchers or target, including necessary
2030  * alignment and padding.
2031  */
2032 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2033                         unsigned int size_left, enum compat_mwt type,
2034                         struct ebt_entries_buf_state *state, const void *base)
2035 {
2036         const char *buf = (const char *)match32;
2037         int growth = 0;
2038
2039         if (size_left == 0)
2040                 return 0;
2041
2042         do {
2043                 struct ebt_entry_match *match_kern;
2044                 int ret;
2045
2046                 if (size_left < sizeof(*match32))
2047                         return -EINVAL;
2048
2049                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2050                 if (match_kern) {
2051                         char *tmp;
2052                         tmp = state->buf_kern_start + state->buf_kern_offset;
2053                         match_kern = (struct ebt_entry_match *) tmp;
2054                 }
2055                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2056                 if (ret < 0)
2057                         return ret;
2058                 size_left -= sizeof(*match32);
2059
2060                 /* add padding before match->data (if any) */
2061                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2062                 if (ret < 0)
2063                         return ret;
2064
2065                 if (match32->match_size > size_left)
2066                         return -EINVAL;
2067
2068                 size_left -= match32->match_size;
2069
2070                 ret = compat_mtw_from_user(match32, type, state, base);
2071                 if (ret < 0)
2072                         return ret;
2073
2074                 if (WARN_ON(ret < match32->match_size))
2075                         return -EINVAL;
2076                 growth += ret - match32->match_size;
2077                 growth += ebt_compat_entry_padsize();
2078
2079                 buf += sizeof(*match32);
2080                 buf += match32->match_size;
2081
2082                 if (match_kern)
2083                         match_kern->match_size = ret;
2084
2085                 match32 = (struct compat_ebt_entry_mwt *) buf;
2086         } while (size_left);
2087
2088         return growth;
2089 }
2090
2091 /* called for all ebt_entry structures. */
2092 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2093                           unsigned int *total,
2094                           struct ebt_entries_buf_state *state)
2095 {
2096         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2097         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2098         unsigned int offsets[4];
2099         unsigned int *offsets_update = NULL;
2100         int ret;
2101         char *buf_start;
2102
2103         if (*total < sizeof(struct ebt_entries))
2104                 return -EINVAL;
2105
2106         if (!entry->bitmask) {
2107                 *total -= sizeof(struct ebt_entries);
2108                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2109         }
2110         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2111                 return -EINVAL;
2112
2113         startoff = state->buf_user_offset;
2114         /* pull in most part of ebt_entry, it does not need to be changed. */
2115         ret = ebt_buf_add(state, entry,
2116                         offsetof(struct ebt_entry, watchers_offset));
2117         if (ret < 0)
2118                 return ret;
2119
2120         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2121         memcpy(&offsets[1], &entry->watchers_offset,
2122                         sizeof(offsets) - sizeof(offsets[0]));
2123
2124         if (state->buf_kern_start) {
2125                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2126                 offsets_update = (unsigned int *) buf_start;
2127         }
2128         ret = ebt_buf_add(state, &offsets[1],
2129                         sizeof(offsets) - sizeof(offsets[0]));
2130         if (ret < 0)
2131                 return ret;
2132         buf_start = (char *) entry;
2133         /* 0: matches offset, always follows ebt_entry.
2134          * 1: watchers offset, from ebt_entry structure
2135          * 2: target offset, from ebt_entry structure
2136          * 3: next ebt_entry offset, from ebt_entry structure
2137          *
2138          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2139          */
2140         for (i = 0; i < 4 ; ++i) {
2141                 if (offsets[i] > *total)
2142                         return -EINVAL;
2143
2144                 if (i < 3 && offsets[i] == *total)
2145                         return -EINVAL;
2146
2147                 if (i == 0)
2148                         continue;
2149                 if (offsets[i-1] > offsets[i])
2150                         return -EINVAL;
2151         }
2152
2153         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2154                 struct compat_ebt_entry_mwt *match32;
2155                 unsigned int size;
2156                 char *buf = buf_start + offsets[i];
2157
2158                 if (offsets[i] > offsets[j])
2159                         return -EINVAL;
2160
2161                 match32 = (struct compat_ebt_entry_mwt *) buf;
2162                 size = offsets[j] - offsets[i];
2163                 ret = ebt_size_mwt(match32, size, i, state, base);
2164                 if (ret < 0)
2165                         return ret;
2166                 new_offset += ret;
2167                 if (offsets_update && new_offset) {
2168                         pr_debug("change offset %d to %d\n",
2169                                 offsets_update[i], offsets[j] + new_offset);
2170                         offsets_update[i] = offsets[j] + new_offset;
2171                 }
2172         }
2173
2174         if (state->buf_kern_start == NULL) {
2175                 unsigned int offset = buf_start - (char *) base;
2176
2177                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2178                 if (ret < 0)
2179                         return ret;
2180         }
2181
2182         next_expected_off = state->buf_user_offset - startoff;
2183         if (next_expected_off != entry->next_offset)
2184                 return -EINVAL;
2185
2186         if (*total < entry->next_offset)
2187                 return -EINVAL;
2188         *total -= entry->next_offset;
2189         return 0;
2190 }
2191
2192 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2193  * It might need more memory when copied to a 64 bit kernel in case
2194  * userspace is 32-bit. So, first task: find out how much memory is needed.
2195  *
2196  * Called before validation is performed.
2197  */
2198 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2199                                 struct ebt_entries_buf_state *state)
2200 {
2201         unsigned int size_remaining = size_user;
2202         int ret;
2203
2204         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2205                                         &size_remaining, state);
2206         if (ret < 0)
2207                 return ret;
2208
2209         if (size_remaining)
2210                 return -EINVAL;
2211
2212         return state->buf_kern_offset;
2213 }
2214
2215
2216 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2217                                              sockptr_t arg, unsigned int len)
2218 {
2219         struct compat_ebt_replace tmp;
2220         int i;
2221
2222         if (len < sizeof(tmp))
2223                 return -EINVAL;
2224
2225         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2226                 return -EFAULT;
2227
2228         if (len != sizeof(tmp) + tmp.entries_size)
2229                 return -EINVAL;
2230
2231         if (tmp.entries_size == 0)
2232                 return -EINVAL;
2233
2234         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2235                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2236                 return -ENOMEM;
2237         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2238                 return -ENOMEM;
2239
2240         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2241
2242         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2243         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2244                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2245
2246         repl->num_counters = tmp.num_counters;
2247         repl->counters = compat_ptr(tmp.counters);
2248         repl->entries = compat_ptr(tmp.entries);
2249         return 0;
2250 }
2251
2252 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2253 {
2254         int ret, i, countersize, size64;
2255         struct ebt_table_info *newinfo;
2256         struct ebt_replace tmp;
2257         struct ebt_entries_buf_state state;
2258         void *entries_tmp;
2259
2260         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2261         if (ret) {
2262                 /* try real handler in case userland supplied needed padding */
2263                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2264                         ret = 0;
2265                 return ret;
2266         }
2267
2268         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2269         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2270         if (!newinfo)
2271                 return -ENOMEM;
2272
2273         if (countersize)
2274                 memset(newinfo->counters, 0, countersize);
2275
2276         memset(&state, 0, sizeof(state));
2277
2278         newinfo->entries = vmalloc(tmp.entries_size);
2279         if (!newinfo->entries) {
2280                 ret = -ENOMEM;
2281                 goto free_newinfo;
2282         }
2283         if (copy_from_user(
2284            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2285                 ret = -EFAULT;
2286                 goto free_entries;
2287         }
2288
2289         entries_tmp = newinfo->entries;
2290
2291         xt_compat_lock(NFPROTO_BRIDGE);
2292
2293         ret = ebt_compat_init_offsets(tmp.nentries);
2294         if (ret < 0)
2295                 goto out_unlock;
2296
2297         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2298         if (ret < 0)
2299                 goto out_unlock;
2300
2301         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2302                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2303                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2304
2305         size64 = ret;
2306         newinfo->entries = vmalloc(size64);
2307         if (!newinfo->entries) {
2308                 vfree(entries_tmp);
2309                 ret = -ENOMEM;
2310                 goto out_unlock;
2311         }
2312
2313         memset(&state, 0, sizeof(state));
2314         state.buf_kern_start = newinfo->entries;
2315         state.buf_kern_len = size64;
2316
2317         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2318         if (WARN_ON(ret < 0)) {
2319                 vfree(entries_tmp);
2320                 goto out_unlock;
2321         }
2322
2323         vfree(entries_tmp);
2324         tmp.entries_size = size64;
2325
2326         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2327                 char __user *usrptr;
2328                 if (tmp.hook_entry[i]) {
2329                         unsigned int delta;
2330                         usrptr = (char __user *) tmp.hook_entry[i];
2331                         delta = usrptr - tmp.entries;
2332                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2333                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2334                 }
2335         }
2336
2337         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2338         xt_compat_unlock(NFPROTO_BRIDGE);
2339
2340         ret = do_replace_finish(net, &tmp, newinfo);
2341         if (ret == 0)
2342                 return ret;
2343 free_entries:
2344         vfree(newinfo->entries);
2345 free_newinfo:
2346         vfree(newinfo);
2347         return ret;
2348 out_unlock:
2349         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2350         xt_compat_unlock(NFPROTO_BRIDGE);
2351         goto free_entries;
2352 }
2353
2354 static int compat_update_counters(struct net *net, sockptr_t arg,
2355                                   unsigned int len)
2356 {
2357         struct compat_ebt_replace hlp;
2358
2359         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2360                 return -EFAULT;
2361
2362         /* try real handler in case userland supplied needed padding */
2363         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2364                 return update_counters(net, arg, len);
2365
2366         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2367                                   hlp.num_counters, len);
2368 }
2369
2370 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2371                 void __user *user, int *len)
2372 {
2373         int ret;
2374         struct compat_ebt_replace tmp;
2375         struct ebt_table *t;
2376         struct net *net = sock_net(sk);
2377
2378         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2379             *len != sizeof(struct compat_ebt_replace))
2380                 return -EINVAL;
2381
2382         if (copy_from_user(&tmp, user, sizeof(tmp)))
2383                 return -EFAULT;
2384
2385         tmp.name[sizeof(tmp.name) - 1] = '\0';
2386
2387         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2388         if (!t)
2389                 return ret;
2390
2391         xt_compat_lock(NFPROTO_BRIDGE);
2392         switch (cmd) {
2393         case EBT_SO_GET_INFO:
2394                 tmp.nentries = t->private->nentries;
2395                 ret = compat_table_info(t->private, &tmp);
2396                 if (ret)
2397                         goto out;
2398                 tmp.valid_hooks = t->valid_hooks;
2399
2400                 if (copy_to_user(user, &tmp, *len) != 0) {
2401                         ret = -EFAULT;
2402                         break;
2403                 }
2404                 ret = 0;
2405                 break;
2406         case EBT_SO_GET_INIT_INFO:
2407                 tmp.nentries = t->table->nentries;
2408                 tmp.entries_size = t->table->entries_size;
2409                 tmp.valid_hooks = t->table->valid_hooks;
2410
2411                 if (copy_to_user(user, &tmp, *len) != 0) {
2412                         ret = -EFAULT;
2413                         break;
2414                 }
2415                 ret = 0;
2416                 break;
2417         case EBT_SO_GET_ENTRIES:
2418         case EBT_SO_GET_INIT_ENTRIES:
2419                 /* try real handler first in case of userland-side padding.
2420                  * in case we are dealing with an 'ordinary' 32 bit binary
2421                  * without 64bit compatibility padding, this will fail right
2422                  * after copy_from_user when the *len argument is validated.
2423                  *
2424                  * the compat_ variant needs to do one pass over the kernel
2425                  * data set to adjust for size differences before it the check.
2426                  */
2427                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2428                         ret = 0;
2429                 else
2430                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2431                 break;
2432         default:
2433                 ret = -EINVAL;
2434         }
2435  out:
2436         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2437         xt_compat_unlock(NFPROTO_BRIDGE);
2438         mutex_unlock(&ebt_mutex);
2439         return ret;
2440 }
2441 #endif
2442
2443 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2444 {
2445         struct net *net = sock_net(sk);
2446         struct ebt_replace tmp;
2447         struct ebt_table *t;
2448         int ret;
2449
2450         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2451                 return -EPERM;
2452
2453 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2454         /* try real handler in case userland supplied needed padding */
2455         if (in_compat_syscall() &&
2456             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2457              *len != sizeof(tmp)))
2458                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2459 #endif
2460
2461         if (copy_from_user(&tmp, user, sizeof(tmp)))
2462                 return -EFAULT;
2463
2464         tmp.name[sizeof(tmp.name) - 1] = '\0';
2465
2466         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2467         if (!t)
2468                 return ret;
2469
2470         switch (cmd) {
2471         case EBT_SO_GET_INFO:
2472         case EBT_SO_GET_INIT_INFO:
2473                 if (*len != sizeof(struct ebt_replace)) {
2474                         ret = -EINVAL;
2475                         mutex_unlock(&ebt_mutex);
2476                         break;
2477                 }
2478                 if (cmd == EBT_SO_GET_INFO) {
2479                         tmp.nentries = t->private->nentries;
2480                         tmp.entries_size = t->private->entries_size;
2481                         tmp.valid_hooks = t->valid_hooks;
2482                 } else {
2483                         tmp.nentries = t->table->nentries;
2484                         tmp.entries_size = t->table->entries_size;
2485                         tmp.valid_hooks = t->table->valid_hooks;
2486                 }
2487                 mutex_unlock(&ebt_mutex);
2488                 if (copy_to_user(user, &tmp, *len) != 0) {
2489                         ret = -EFAULT;
2490                         break;
2491                 }
2492                 ret = 0;
2493                 break;
2494
2495         case EBT_SO_GET_ENTRIES:
2496         case EBT_SO_GET_INIT_ENTRIES:
2497                 ret = copy_everything_to_user(t, user, len, cmd);
2498                 mutex_unlock(&ebt_mutex);
2499                 break;
2500
2501         default:
2502                 mutex_unlock(&ebt_mutex);
2503                 ret = -EINVAL;
2504         }
2505
2506         return ret;
2507 }
2508
2509 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2510                 unsigned int len)
2511 {
2512         struct net *net = sock_net(sk);
2513         int ret;
2514
2515         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2516                 return -EPERM;
2517
2518         switch (cmd) {
2519         case EBT_SO_SET_ENTRIES:
2520 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2521                 if (in_compat_syscall())
2522                         ret = compat_do_replace(net, arg, len);
2523                 else
2524 #endif
2525                         ret = do_replace(net, arg, len);
2526                 break;
2527         case EBT_SO_SET_COUNTERS:
2528 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2529                 if (in_compat_syscall())
2530                         ret = compat_update_counters(net, arg, len);
2531                 else
2532 #endif
2533                         ret = update_counters(net, arg, len);
2534                 break;
2535         default:
2536                 ret = -EINVAL;
2537         }
2538         return ret;
2539 }
2540
2541 static struct nf_sockopt_ops ebt_sockopts = {
2542         .pf             = PF_INET,
2543         .set_optmin     = EBT_BASE_CTL,
2544         .set_optmax     = EBT_SO_SET_MAX + 1,
2545         .set            = do_ebt_set_ctl,
2546         .get_optmin     = EBT_BASE_CTL,
2547         .get_optmax     = EBT_SO_GET_MAX + 1,
2548         .get            = do_ebt_get_ctl,
2549         .owner          = THIS_MODULE,
2550 };
2551
2552 static int __net_init ebt_pernet_init(struct net *net)
2553 {
2554         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2555
2556         INIT_LIST_HEAD(&ebt_net->tables);
2557         return 0;
2558 }
2559
2560 static struct pernet_operations ebt_net_ops = {
2561         .init = ebt_pernet_init,
2562         .id   = &ebt_pernet_id,
2563         .size = sizeof(struct ebt_pernet),
2564 };
2565
2566 static int __init ebtables_init(void)
2567 {
2568         int ret;
2569
2570         ret = xt_register_target(&ebt_standard_target);
2571         if (ret < 0)
2572                 return ret;
2573         ret = nf_register_sockopt(&ebt_sockopts);
2574         if (ret < 0) {
2575                 xt_unregister_target(&ebt_standard_target);
2576                 return ret;
2577         }
2578
2579         ret = register_pernet_subsys(&ebt_net_ops);
2580         if (ret < 0) {
2581                 nf_unregister_sockopt(&ebt_sockopts);
2582                 xt_unregister_target(&ebt_standard_target);
2583                 return ret;
2584         }
2585
2586         return 0;
2587 }
2588
2589 static void ebtables_fini(void)
2590 {
2591         nf_unregister_sockopt(&ebt_sockopts);
2592         xt_unregister_target(&ebt_standard_target);
2593         unregister_pernet_subsys(&ebt_net_ops);
2594 }
2595
2596 EXPORT_SYMBOL(ebt_register_table);
2597 EXPORT_SYMBOL(ebt_unregister_table);
2598 EXPORT_SYMBOL(ebt_do_table);
2599 module_init(ebtables_init);
2600 module_exit(ebtables_fini);
2601 MODULE_LICENSE("GPL");