net/bridge/netfilter/ebtables.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ebtables
   4  *
   5  *  Author:
   6  *  Bart De Schuymer            <[email protected]>
   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(void *priv, struct sk_buff *skb,
 193                           const struct nf_hook_state *state)
 194 {
 195         struct ebt_table *table = priv;
 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         if (repl->valid_hooks != t->valid_hooks) {
1044                 ret = -EINVAL;
1045                 goto free_unlock;
1046         }
1047
1048         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1049                 ret = -EINVAL;
1050                 goto free_unlock;
1051         }
1052
1053         /* we have the mutex lock, so no danger in reading this pointer */
1054         table = t->private;
1055         /* make sure the table can only be rmmod'ed if it contains no rules */
1056         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1057                 ret = -ENOENT;
1058                 goto free_unlock;
1059         } else if (table->nentries && !newinfo->nentries)
1060                 module_put(t->me);
1061         /* we need an atomic snapshot of the counters */
1062         write_lock_bh(&t->lock);
1063         if (repl->num_counters)
1064                 get_counters(t->private->counters, counterstmp,
1065                    t->private->nentries);
1066
1067         t->private = newinfo;
1068         write_unlock_bh(&t->lock);
1069         mutex_unlock(&ebt_mutex);
1070         /* so, a user can change the chains while having messed up her counter
1071          * allocation. Only reason why this is done is because this way the lock
1072          * is held only once, while this doesn't bring the kernel into a
1073          * dangerous state.
1074          */
1075         if (repl->num_counters &&
1076            copy_to_user(repl->counters, counterstmp,
1077            array_size(repl->num_counters, sizeof(struct ebt_counter)))) {
1078                 /* Silent error, can't fail, new table is already in place */
1079                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1080         }
1081
1082         /* decrease module count and free resources */
1083         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1084                           ebt_cleanup_entry, net, NULL);
1085
1086         vfree(table->entries);
1087         ebt_free_table_info(table);
1088         vfree(table);
1089         vfree(counterstmp);
1090
1091         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1092                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1093         return 0;
1094
1095 free_unlock:
1096         mutex_unlock(&ebt_mutex);
1097 free_iterate:
1098         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1099                           ebt_cleanup_entry, net, NULL);
1100 free_counterstmp:
1101         vfree(counterstmp);
1102         /* can be initialized in translate_table() */
1103         ebt_free_table_info(newinfo);
1104         return ret;
1105 }
1106
1107 /* replace the table */
1108 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1109 {
1110         int ret, countersize;
1111         struct ebt_table_info *newinfo;
1112         struct ebt_replace tmp;
1113
1114         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1115                 return -EFAULT;
1116
1117         if (len != sizeof(tmp) + tmp.entries_size)
1118                 return -EINVAL;
1119
1120         if (tmp.entries_size == 0)
1121                 return -EINVAL;
1122
1123         /* overflow check */
1124         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1125                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1126                 return -ENOMEM;
1127         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1128                 return -ENOMEM;
1129
1130         tmp.name[sizeof(tmp.name) - 1] = 0;
1131
1132         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1133         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1134         if (!newinfo)
1135                 return -ENOMEM;
1136
1137         if (countersize)
1138                 memset(newinfo->counters, 0, countersize);
1139
1140         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1141         if (!newinfo->entries) {
1142                 ret = -ENOMEM;
1143                 goto free_newinfo;
1144         }
1145         if (copy_from_user(
1146            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1147                 ret = -EFAULT;
1148                 goto free_entries;
1149         }
1150
1151         ret = do_replace_finish(net, &tmp, newinfo);
1152         if (ret == 0)
1153                 return ret;
1154 free_entries:
1155         vfree(newinfo->entries);
1156 free_newinfo:
1157         vfree(newinfo);
1158         return ret;
1159 }
1160
1161 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1162 {
1163         mutex_lock(&ebt_mutex);
1164         list_del(&table->list);
1165         mutex_unlock(&ebt_mutex);
1166         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1167                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1168         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1169                           ebt_cleanup_entry, net, NULL);
1170         if (table->private->nentries)
1171                 module_put(table->me);
1172         vfree(table->private->entries);
1173         ebt_free_table_info(table->private);
1174         vfree(table->private);
1175         kfree(table->ops);
1176         kfree(table);
1177 }
1178
1179 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1180                        const struct nf_hook_ops *template_ops)
1181 {
1182         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1183         struct ebt_table_info *newinfo;
1184         struct ebt_table *t, *table;
1185         struct nf_hook_ops *ops;
1186         unsigned int num_ops;
1187         struct ebt_replace_kernel *repl;
1188         int ret, i, countersize;
1189         void *p;
1190
1191         if (input_table == NULL || (repl = input_table->table) == NULL ||
1192             repl->entries == NULL || repl->entries_size == 0 ||
1193             repl->counters != NULL || input_table->private != NULL)
1194                 return -EINVAL;
1195
1196         /* Don't add one table to multiple lists. */
1197         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1198         if (!table) {
1199                 ret = -ENOMEM;
1200                 goto out;
1201         }
1202
1203         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1204         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1205         ret = -ENOMEM;
1206         if (!newinfo)
1207                 goto free_table;
1208
1209         p = vmalloc(repl->entries_size);
1210         if (!p)
1211                 goto free_newinfo;
1212
1213         memcpy(p, repl->entries, repl->entries_size);
1214         newinfo->entries = p;
1215
1216         newinfo->entries_size = repl->entries_size;
1217         newinfo->nentries = repl->nentries;
1218
1219         if (countersize)
1220                 memset(newinfo->counters, 0, countersize);
1221
1222         /* fill in newinfo and parse the entries */
1223         newinfo->chainstack = NULL;
1224         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1225                 if ((repl->valid_hooks & (1 << i)) == 0)
1226                         newinfo->hook_entry[i] = NULL;
1227                 else
1228                         newinfo->hook_entry[i] = p +
1229                                 ((char *)repl->hook_entry[i] - repl->entries);
1230         }
1231         ret = translate_table(net, repl->name, newinfo);
1232         if (ret != 0)
1233                 goto free_chainstack;
1234
1235         table->private = newinfo;
1236         rwlock_init(&table->lock);
1237         mutex_lock(&ebt_mutex);
1238         list_for_each_entry(t, &ebt_net->tables, list) {
1239                 if (strcmp(t->name, table->name) == 0) {
1240                         ret = -EEXIST;
1241                         goto free_unlock;
1242                 }
1243         }
1244
1245         /* Hold a reference count if the chains aren't empty */
1246         if (newinfo->nentries && !try_module_get(table->me)) {
1247                 ret = -ENOENT;
1248                 goto free_unlock;
1249         }
1250
1251         num_ops = hweight32(table->valid_hooks);
1252         if (num_ops == 0) {
1253                 ret = -EINVAL;
1254                 goto free_unlock;
1255         }
1256
1257         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1258         if (!ops) {
1259                 ret = -ENOMEM;
1260                 if (newinfo->nentries)
1261                         module_put(table->me);
1262                 goto free_unlock;
1263         }
1264
1265         for (i = 0; i < num_ops; i++)
1266                 ops[i].priv = table;
1267
1268         list_add(&table->list, &ebt_net->tables);
1269         mutex_unlock(&ebt_mutex);
1270
1271         table->ops = ops;
1272         ret = nf_register_net_hooks(net, ops, num_ops);
1273         if (ret)
1274                 __ebt_unregister_table(net, table);
1275
1276         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1277                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1278         return ret;
1279 free_unlock:
1280         mutex_unlock(&ebt_mutex);
1281 free_chainstack:
1282         ebt_free_table_info(newinfo);
1283         vfree(newinfo->entries);
1284 free_newinfo:
1285         vfree(newinfo);
1286 free_table:
1287         kfree(table);
1288 out:
1289         return ret;
1290 }
1291
1292 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1293 {
1294         struct ebt_template *tmpl;
1295
1296         mutex_lock(&ebt_mutex);
1297         list_for_each_entry(tmpl, &template_tables, list) {
1298                 if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1299                         mutex_unlock(&ebt_mutex);
1300                         return -EEXIST;
1301                 }
1302         }
1303
1304         tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1305         if (!tmpl) {
1306                 mutex_unlock(&ebt_mutex);
1307                 return -ENOMEM;
1308         }
1309
1310         tmpl->table_init = table_init;
1311         strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1312         tmpl->owner = t->me;
1313         list_add(&tmpl->list, &template_tables);
1314
1315         mutex_unlock(&ebt_mutex);
1316         return 0;
1317 }
1318 EXPORT_SYMBOL(ebt_register_template);
1319
1320 void ebt_unregister_template(const struct ebt_table *t)
1321 {
1322         struct ebt_template *tmpl;
1323
1324         mutex_lock(&ebt_mutex);
1325         list_for_each_entry(tmpl, &template_tables, list) {
1326                 if (strcmp(t->name, tmpl->name))
1327                         continue;
1328
1329                 list_del(&tmpl->list);
1330                 mutex_unlock(&ebt_mutex);
1331                 kfree(tmpl);
1332                 return;
1333         }
1334
1335         mutex_unlock(&ebt_mutex);
1336         WARN_ON_ONCE(1);
1337 }
1338 EXPORT_SYMBOL(ebt_unregister_template);
1339
1340 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1341 {
1342         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1343         struct ebt_table *t;
1344
1345         mutex_lock(&ebt_mutex);
1346
1347         list_for_each_entry(t, &ebt_net->tables, list) {
1348                 if (strcmp(t->name, name) == 0) {
1349                         mutex_unlock(&ebt_mutex);
1350                         return t;
1351                 }
1352         }
1353
1354         mutex_unlock(&ebt_mutex);
1355         return NULL;
1356 }
1357
1358 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1359 {
1360         struct ebt_table *table = __ebt_find_table(net, name);
1361
1362         if (table)
1363                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1364 }
1365 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1366
1367 void ebt_unregister_table(struct net *net, const char *name)
1368 {
1369         struct ebt_table *table = __ebt_find_table(net, name);
1370
1371         if (table)
1372                 __ebt_unregister_table(net, table);
1373 }
1374
1375 /* userspace just supplied us with counters */
1376 static int do_update_counters(struct net *net, const char *name,
1377                               struct ebt_counter __user *counters,
1378                               unsigned int num_counters, unsigned int len)
1379 {
1380         int i, ret;
1381         struct ebt_counter *tmp;
1382         struct ebt_table *t;
1383
1384         if (num_counters == 0)
1385                 return -EINVAL;
1386
1387         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1388         if (!tmp)
1389                 return -ENOMEM;
1390
1391         t = find_table_lock(net, name, &ret, &ebt_mutex);
1392         if (!t)
1393                 goto free_tmp;
1394
1395         if (num_counters != t->private->nentries) {
1396                 ret = -EINVAL;
1397                 goto unlock_mutex;
1398         }
1399
1400         if (copy_from_user(tmp, counters,
1401                            array_size(num_counters, sizeof(*counters)))) {
1402                 ret = -EFAULT;
1403                 goto unlock_mutex;
1404         }
1405
1406         /* we want an atomic add of the counters */
1407         write_lock_bh(&t->lock);
1408
1409         /* we add to the counters of the first cpu */
1410         for (i = 0; i < num_counters; i++)
1411                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1412
1413         write_unlock_bh(&t->lock);
1414         ret = 0;
1415 unlock_mutex:
1416         mutex_unlock(&ebt_mutex);
1417 free_tmp:
1418         vfree(tmp);
1419         return ret;
1420 }
1421
1422 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1423 {
1424         struct ebt_replace hlp;
1425
1426         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1427                 return -EFAULT;
1428
1429         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1430                 return -EINVAL;
1431
1432         return do_update_counters(net, hlp.name, hlp.counters,
1433                                   hlp.num_counters, len);
1434 }
1435
1436 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1437                                   const char *data, int entrysize,
1438                                   int usersize, int datasize, u8 revision)
1439 {
1440         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1441
1442         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1443          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1444          */
1445         strscpy(name, _name, sizeof(name));
1446         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1447             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1448             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1449             xt_data_to_user(um + entrysize, data, usersize, datasize,
1450                             XT_ALIGN(datasize)))
1451                 return -EFAULT;
1452
1453         return 0;
1454 }
1455
1456 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1457                                     const char *base, char __user *ubase)
1458 {
1459         return ebt_obj_to_user(ubase + ((char *)m - base),
1460                                m->u.match->name, m->data, sizeof(*m),
1461                                m->u.match->usersize, m->match_size,
1462                                m->u.match->revision);
1463 }
1464
1465 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1466                                       const char *base, char __user *ubase)
1467 {
1468         return ebt_obj_to_user(ubase + ((char *)w - base),
1469                                w->u.watcher->name, w->data, sizeof(*w),
1470                                w->u.watcher->usersize, w->watcher_size,
1471                                w->u.watcher->revision);
1472 }
1473
1474 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1475                                     char __user *ubase)
1476 {
1477         int ret;
1478         char __user *hlp;
1479         const struct ebt_entry_target *t;
1480
1481         if (e->bitmask == 0) {
1482                 /* special case !EBT_ENTRY_OR_ENTRIES */
1483                 if (copy_to_user(ubase + ((char *)e - base), e,
1484                                  sizeof(struct ebt_entries)))
1485                         return -EFAULT;
1486                 return 0;
1487         }
1488
1489         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1490                 return -EFAULT;
1491
1492         hlp = ubase + (((char *)e + e->target_offset) - base);
1493         t = ebt_get_target_c(e);
1494
1495         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1496         if (ret != 0)
1497                 return ret;
1498         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1499         if (ret != 0)
1500                 return ret;
1501         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1502                               t->u.target->usersize, t->target_size,
1503                               t->u.target->revision);
1504         if (ret != 0)
1505                 return ret;
1506
1507         return 0;
1508 }
1509
1510 static int copy_counters_to_user(struct ebt_table *t,
1511                                  const struct ebt_counter *oldcounters,
1512                                  void __user *user, unsigned int num_counters,
1513                                  unsigned int nentries)
1514 {
1515         struct ebt_counter *counterstmp;
1516         int ret = 0;
1517
1518         /* userspace might not need the counters */
1519         if (num_counters == 0)
1520                 return 0;
1521
1522         if (num_counters != nentries)
1523                 return -EINVAL;
1524
1525         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1526         if (!counterstmp)
1527                 return -ENOMEM;
1528
1529         write_lock_bh(&t->lock);
1530         get_counters(oldcounters, counterstmp, nentries);
1531         write_unlock_bh(&t->lock);
1532
1533         if (copy_to_user(user, counterstmp,
1534             array_size(nentries, sizeof(struct ebt_counter))))
1535                 ret = -EFAULT;
1536         vfree(counterstmp);
1537         return ret;
1538 }
1539
1540 /* called with ebt_mutex locked */
1541 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1542                                    const int *len, int cmd)
1543 {
1544         struct ebt_replace tmp;
1545         const struct ebt_counter *oldcounters;
1546         unsigned int entries_size, nentries;
1547         int ret;
1548         char *entries;
1549
1550         if (cmd == EBT_SO_GET_ENTRIES) {
1551                 entries_size = t->private->entries_size;
1552                 nentries = t->private->nentries;
1553                 entries = t->private->entries;
1554                 oldcounters = t->private->counters;
1555         } else {
1556                 entries_size = t->table->entries_size;
1557                 nentries = t->table->nentries;
1558                 entries = t->table->entries;
1559                 oldcounters = t->table->counters;
1560         }
1561
1562         if (copy_from_user(&tmp, user, sizeof(tmp)))
1563                 return -EFAULT;
1564
1565         if (*len != sizeof(struct ebt_replace) + entries_size +
1566            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1567                 return -EINVAL;
1568
1569         if (tmp.nentries != nentries)
1570                 return -EINVAL;
1571
1572         if (tmp.entries_size != entries_size)
1573                 return -EINVAL;
1574
1575         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1576                                         tmp.num_counters, nentries);
1577         if (ret)
1578                 return ret;
1579
1580         /* set the match/watcher/target names right */
1581         return EBT_ENTRY_ITERATE(entries, entries_size,
1582            ebt_entry_to_user, entries, tmp.entries);
1583 }
1584
1585 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1586 /* 32 bit-userspace compatibility definitions. */
1587 struct compat_ebt_replace {
1588         char name[EBT_TABLE_MAXNAMELEN];
1589         compat_uint_t valid_hooks;
1590         compat_uint_t nentries;
1591         compat_uint_t entries_size;
1592         /* start of the chains */
1593         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1594         /* nr of counters userspace expects back */
1595         compat_uint_t num_counters;
1596         /* where the kernel will put the old counters. */
1597         compat_uptr_t counters;
1598         compat_uptr_t entries;
1599 };
1600
1601 /* struct ebt_entry_match, _target and _watcher have same layout */
1602 struct compat_ebt_entry_mwt {
1603         union {
1604                 struct {
1605                         char name[EBT_EXTENSION_MAXNAMELEN];
1606                         u8 revision;
1607                 };
1608                 compat_uptr_t ptr;
1609         } u;
1610         compat_uint_t match_size;
1611         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1612 };
1613
1614 /* account for possible padding between match_size and ->data */
1615 static int ebt_compat_entry_padsize(void)
1616 {
1617         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1618                         sizeof(struct compat_ebt_entry_mwt));
1619         return (int) sizeof(struct ebt_entry_match) -
1620                         sizeof(struct compat_ebt_entry_mwt);
1621 }
1622
1623 static int ebt_compat_match_offset(const struct xt_match *match,
1624                                    unsigned int userlen)
1625 {
1626         /* ebt_among needs special handling. The kernel .matchsize is
1627          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1628          * value is expected.
1629          * Example: userspace sends 4500, ebt_among.c wants 4504.
1630          */
1631         if (unlikely(match->matchsize == -1))
1632                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1633         return xt_compat_match_offset(match);
1634 }
1635
1636 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1637                                 unsigned int *size)
1638 {
1639         const struct xt_match *match = m->u.match;
1640         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1641         int off = ebt_compat_match_offset(match, m->match_size);
1642         compat_uint_t msize = m->match_size - off;
1643
1644         if (WARN_ON(off >= m->match_size))
1645                 return -EINVAL;
1646
1647         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1648             put_user(match->revision, &cm->u.revision) ||
1649             put_user(msize, &cm->match_size))
1650                 return -EFAULT;
1651
1652         if (match->compat_to_user) {
1653                 if (match->compat_to_user(cm->data, m->data))
1654                         return -EFAULT;
1655         } else {
1656                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1657                                     COMPAT_XT_ALIGN(msize)))
1658                         return -EFAULT;
1659         }
1660
1661         *size -= ebt_compat_entry_padsize() + off;
1662         *dstptr = cm->data;
1663         *dstptr += msize;
1664         return 0;
1665 }
1666
1667 static int compat_target_to_user(struct ebt_entry_target *t,
1668                                  void __user **dstptr,
1669                                  unsigned int *size)
1670 {
1671         const struct xt_target *target = t->u.target;
1672         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1673         int off = xt_compat_target_offset(target);
1674         compat_uint_t tsize = t->target_size - off;
1675
1676         if (WARN_ON(off >= t->target_size))
1677                 return -EINVAL;
1678
1679         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1680             put_user(target->revision, &cm->u.revision) ||
1681             put_user(tsize, &cm->match_size))
1682                 return -EFAULT;
1683
1684         if (target->compat_to_user) {
1685                 if (target->compat_to_user(cm->data, t->data))
1686                         return -EFAULT;
1687         } else {
1688                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1689                                     COMPAT_XT_ALIGN(tsize)))
1690                         return -EFAULT;
1691         }
1692
1693         *size -= ebt_compat_entry_padsize() + off;
1694         *dstptr = cm->data;
1695         *dstptr += tsize;
1696         return 0;
1697 }
1698
1699 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1700                                   void __user **dstptr,
1701                                   unsigned int *size)
1702 {
1703         return compat_target_to_user((struct ebt_entry_target *)w,
1704                                                         dstptr, size);
1705 }
1706
1707 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1708                                 unsigned int *size)
1709 {
1710         struct ebt_entry_target *t;
1711         struct ebt_entry __user *ce;
1712         u32 watchers_offset, target_offset, next_offset;
1713         compat_uint_t origsize;
1714         int ret;
1715
1716         if (e->bitmask == 0) {
1717                 if (*size < sizeof(struct ebt_entries))
1718                         return -EINVAL;
1719                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1720                         return -EFAULT;
1721
1722                 *dstptr += sizeof(struct ebt_entries);
1723                 *size -= sizeof(struct ebt_entries);
1724                 return 0;
1725         }
1726
1727         if (*size < sizeof(*ce))
1728                 return -EINVAL;
1729
1730         ce = *dstptr;
1731         if (copy_to_user(ce, e, sizeof(*ce)))
1732                 return -EFAULT;
1733
1734         origsize = *size;
1735         *dstptr += sizeof(*ce);
1736
1737         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1738         if (ret)
1739                 return ret;
1740         watchers_offset = e->watchers_offset - (origsize - *size);
1741
1742         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1743         if (ret)
1744                 return ret;
1745         target_offset = e->target_offset - (origsize - *size);
1746
1747         t = ebt_get_target(e);
1748
1749         ret = compat_target_to_user(t, dstptr, size);
1750         if (ret)
1751                 return ret;
1752         next_offset = e->next_offset - (origsize - *size);
1753
1754         if (put_user(watchers_offset, &ce->watchers_offset) ||
1755             put_user(target_offset, &ce->target_offset) ||
1756             put_user(next_offset, &ce->next_offset))
1757                 return -EFAULT;
1758
1759         *size -= sizeof(*ce);
1760         return 0;
1761 }
1762
1763 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1764 {
1765         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1766         *off += ebt_compat_entry_padsize();
1767         return 0;
1768 }
1769
1770 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1771 {
1772         *off += xt_compat_target_offset(w->u.watcher);
1773         *off += ebt_compat_entry_padsize();
1774         return 0;
1775 }
1776
1777 static int compat_calc_entry(const struct ebt_entry *e,
1778                              const struct ebt_table_info *info,
1779                              const void *base,
1780                              struct compat_ebt_replace *newinfo)
1781 {
1782         const struct ebt_entry_target *t;
1783         unsigned int entry_offset;
1784         int off, ret, i;
1785
1786         if (e->bitmask == 0)
1787                 return 0;
1788
1789         off = 0;
1790         entry_offset = (void *)e - base;
1791
1792         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1793         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1794
1795         t = ebt_get_target_c(e);
1796
1797         off += xt_compat_target_offset(t->u.target);
1798         off += ebt_compat_entry_padsize();
1799
1800         newinfo->entries_size -= off;
1801
1802         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1803         if (ret)
1804                 return ret;
1805
1806         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1807                 const void *hookptr = info->hook_entry[i];
1808                 if (info->hook_entry[i] &&
1809                     (e < (struct ebt_entry *)(base - hookptr))) {
1810                         newinfo->hook_entry[i] -= off;
1811                         pr_debug("0x%08X -> 0x%08X\n",
1812                                         newinfo->hook_entry[i] + off,
1813                                         newinfo->hook_entry[i]);
1814                 }
1815         }
1816
1817         return 0;
1818 }
1819
1820 static int ebt_compat_init_offsets(unsigned int number)
1821 {
1822         if (number > INT_MAX)
1823                 return -EINVAL;
1824
1825         /* also count the base chain policies */
1826         number += NF_BR_NUMHOOKS;
1827
1828         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1829 }
1830
1831 static int compat_table_info(const struct ebt_table_info *info,
1832                              struct compat_ebt_replace *newinfo)
1833 {
1834         unsigned int size = info->entries_size;
1835         const void *entries = info->entries;
1836         int ret;
1837
1838         newinfo->entries_size = size;
1839         ret = ebt_compat_init_offsets(info->nentries);
1840         if (ret)
1841                 return ret;
1842
1843         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1844                                                         entries, newinfo);
1845 }
1846
1847 static int compat_copy_everything_to_user(struct ebt_table *t,
1848                                           void __user *user, int *len, int cmd)
1849 {
1850         struct compat_ebt_replace repl, tmp;
1851         struct ebt_counter *oldcounters;
1852         struct ebt_table_info tinfo;
1853         int ret;
1854         void __user *pos;
1855
1856         memset(&tinfo, 0, sizeof(tinfo));
1857
1858         if (cmd == EBT_SO_GET_ENTRIES) {
1859                 tinfo.entries_size = t->private->entries_size;
1860                 tinfo.nentries = t->private->nentries;
1861                 tinfo.entries = t->private->entries;
1862                 oldcounters = t->private->counters;
1863         } else {
1864                 tinfo.entries_size = t->table->entries_size;
1865                 tinfo.nentries = t->table->nentries;
1866                 tinfo.entries = t->table->entries;
1867                 oldcounters = t->table->counters;
1868         }
1869
1870         if (copy_from_user(&tmp, user, sizeof(tmp)))
1871                 return -EFAULT;
1872
1873         if (tmp.nentries != tinfo.nentries ||
1874            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1875                 return -EINVAL;
1876
1877         memcpy(&repl, &tmp, sizeof(repl));
1878         if (cmd == EBT_SO_GET_ENTRIES)
1879                 ret = compat_table_info(t->private, &repl);
1880         else
1881                 ret = compat_table_info(&tinfo, &repl);
1882         if (ret)
1883                 return ret;
1884
1885         if (*len != sizeof(tmp) + repl.entries_size +
1886            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1887                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1888                                 *len, tinfo.entries_size, repl.entries_size);
1889                 return -EINVAL;
1890         }
1891
1892         /* userspace might not need the counters */
1893         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1894                                         tmp.num_counters, tinfo.nentries);
1895         if (ret)
1896                 return ret;
1897
1898         pos = compat_ptr(tmp.entries);
1899         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1900                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1901 }
1902
1903 struct ebt_entries_buf_state {
1904         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1905         u32 buf_kern_len;       /* total size of kernel buffer */
1906         u32 buf_kern_offset;    /* amount of data copied so far */
1907         u32 buf_user_offset;    /* read position in userspace buffer */
1908 };
1909
1910 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1911 {
1912         state->buf_kern_offset += sz;
1913         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1914 }
1915
1916 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1917                        const void *data, unsigned int sz)
1918 {
1919         if (state->buf_kern_start == NULL)
1920                 goto count_only;
1921
1922         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1923                 return -EINVAL;
1924
1925         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1926
1927  count_only:
1928         state->buf_user_offset += sz;
1929         return ebt_buf_count(state, sz);
1930 }
1931
1932 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1933 {
1934         char *b = state->buf_kern_start;
1935
1936         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1937                 return -EINVAL;
1938
1939         if (b != NULL && sz > 0)
1940                 memset(b + state->buf_kern_offset, 0, sz);
1941         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1942         return ebt_buf_count(state, sz);
1943 }
1944
1945 enum compat_mwt {
1946         EBT_COMPAT_MATCH,
1947         EBT_COMPAT_WATCHER,
1948         EBT_COMPAT_TARGET,
1949 };
1950
1951 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1952                                 enum compat_mwt compat_mwt,
1953                                 struct ebt_entries_buf_state *state,
1954                                 const unsigned char *base)
1955 {
1956         char name[EBT_EXTENSION_MAXNAMELEN];
1957         struct xt_match *match;
1958         struct xt_target *wt;
1959         void *dst = NULL;
1960         int off, pad = 0;
1961         unsigned int size_kern, match_size = mwt->match_size;
1962
1963         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1964                 return -EINVAL;
1965
1966         if (state->buf_kern_start)
1967                 dst = state->buf_kern_start + state->buf_kern_offset;
1968
1969         switch (compat_mwt) {
1970         case EBT_COMPAT_MATCH:
1971                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1972                                               mwt->u.revision);
1973                 if (IS_ERR(match))
1974                         return PTR_ERR(match);
1975
1976                 off = ebt_compat_match_offset(match, match_size);
1977                 if (dst) {
1978                         if (match->compat_from_user)
1979                                 match->compat_from_user(dst, mwt->data);
1980                         else
1981                                 memcpy(dst, mwt->data, match_size);
1982                 }
1983
1984                 size_kern = match->matchsize;
1985                 if (unlikely(size_kern == -1))
1986                         size_kern = match_size;
1987                 module_put(match->me);
1988                 break;
1989         case EBT_COMPAT_WATCHER:
1990         case EBT_COMPAT_TARGET:
1991                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1992                                             mwt->u.revision);
1993                 if (IS_ERR(wt))
1994                         return PTR_ERR(wt);
1995                 off = xt_compat_target_offset(wt);
1996
1997                 if (dst) {
1998                         if (wt->compat_from_user)
1999                                 wt->compat_from_user(dst, mwt->data);
2000                         else
2001                                 memcpy(dst, mwt->data, match_size);
2002                 }
2003
2004                 size_kern = wt->targetsize;
2005                 module_put(wt->me);
2006                 break;
2007
2008         default:
2009                 return -EINVAL;
2010         }
2011
2012         state->buf_kern_offset += match_size + off;
2013         state->buf_user_offset += match_size;
2014         pad = XT_ALIGN(size_kern) - size_kern;
2015
2016         if (pad > 0 && dst) {
2017                 if (WARN_ON(state->buf_kern_len <= pad))
2018                         return -EINVAL;
2019                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2020                         return -EINVAL;
2021                 memset(dst + size_kern, 0, pad);
2022         }
2023         return off + match_size;
2024 }
2025
2026 /* return size of all matches, watchers or target, including necessary
2027  * alignment and padding.
2028  */
2029 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2030                         unsigned int size_left, enum compat_mwt type,
2031                         struct ebt_entries_buf_state *state, const void *base)
2032 {
2033         const char *buf = (const char *)match32;
2034         int growth = 0;
2035
2036         if (size_left == 0)
2037                 return 0;
2038
2039         do {
2040                 struct ebt_entry_match *match_kern;
2041                 int ret;
2042
2043                 if (size_left < sizeof(*match32))
2044                         return -EINVAL;
2045
2046                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2047                 if (match_kern) {
2048                         char *tmp;
2049                         tmp = state->buf_kern_start + state->buf_kern_offset;
2050                         match_kern = (struct ebt_entry_match *) tmp;
2051                 }
2052                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2053                 if (ret < 0)
2054                         return ret;
2055                 size_left -= sizeof(*match32);
2056
2057                 /* add padding before match->data (if any) */
2058                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2059                 if (ret < 0)
2060                         return ret;
2061
2062                 if (match32->match_size > size_left)
2063                         return -EINVAL;
2064
2065                 size_left -= match32->match_size;
2066
2067                 ret = compat_mtw_from_user(match32, type, state, base);
2068                 if (ret < 0)
2069                         return ret;
2070
2071                 if (WARN_ON(ret < match32->match_size))
2072                         return -EINVAL;
2073                 growth += ret - match32->match_size;
2074                 growth += ebt_compat_entry_padsize();
2075
2076                 buf += sizeof(*match32);
2077                 buf += match32->match_size;
2078
2079                 if (match_kern)
2080                         match_kern->match_size = ret;
2081
2082                 match32 = (struct compat_ebt_entry_mwt *) buf;
2083         } while (size_left);
2084
2085         return growth;
2086 }
2087
2088 /* called for all ebt_entry structures. */
2089 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2090                           unsigned int *total,
2091                           struct ebt_entries_buf_state *state)
2092 {
2093         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2094         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2095         unsigned int offsets[4];
2096         unsigned int *offsets_update = NULL;
2097         int ret;
2098         char *buf_start;
2099
2100         if (*total < sizeof(struct ebt_entries))
2101                 return -EINVAL;
2102
2103         if (!entry->bitmask) {
2104                 *total -= sizeof(struct ebt_entries);
2105                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2106         }
2107         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2108                 return -EINVAL;
2109
2110         startoff = state->buf_user_offset;
2111         /* pull in most part of ebt_entry, it does not need to be changed. */
2112         ret = ebt_buf_add(state, entry,
2113                         offsetof(struct ebt_entry, watchers_offset));
2114         if (ret < 0)
2115                 return ret;
2116
2117         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2118         memcpy(&offsets[1], &entry->watchers_offset,
2119                         sizeof(offsets) - sizeof(offsets[0]));
2120
2121         if (state->buf_kern_start) {
2122                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2123                 offsets_update = (unsigned int *) buf_start;
2124         }
2125         ret = ebt_buf_add(state, &offsets[1],
2126                         sizeof(offsets) - sizeof(offsets[0]));
2127         if (ret < 0)
2128                 return ret;
2129         buf_start = (char *) entry;
2130         /* 0: matches offset, always follows ebt_entry.
2131          * 1: watchers offset, from ebt_entry structure
2132          * 2: target offset, from ebt_entry structure
2133          * 3: next ebt_entry offset, from ebt_entry structure
2134          *
2135          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2136          */
2137         for (i = 0; i < 4 ; ++i) {
2138                 if (offsets[i] > *total)
2139                         return -EINVAL;
2140
2141                 if (i < 3 && offsets[i] == *total)
2142                         return -EINVAL;
2143
2144                 if (i == 0)
2145                         continue;
2146                 if (offsets[i-1] > offsets[i])
2147                         return -EINVAL;
2148         }
2149
2150         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2151                 struct compat_ebt_entry_mwt *match32;
2152                 unsigned int size;
2153                 char *buf = buf_start + offsets[i];
2154
2155                 if (offsets[i] > offsets[j])
2156                         return -EINVAL;
2157
2158                 match32 = (struct compat_ebt_entry_mwt *) buf;
2159                 size = offsets[j] - offsets[i];
2160                 ret = ebt_size_mwt(match32, size, i, state, base);
2161                 if (ret < 0)
2162                         return ret;
2163                 new_offset += ret;
2164                 if (offsets_update && new_offset) {
2165                         pr_debug("change offset %d to %d\n",
2166                                 offsets_update[i], offsets[j] + new_offset);
2167                         offsets_update[i] = offsets[j] + new_offset;
2168                 }
2169         }
2170
2171         if (state->buf_kern_start == NULL) {
2172                 unsigned int offset = buf_start - (char *) base;
2173
2174                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2175                 if (ret < 0)
2176                         return ret;
2177         }
2178
2179         next_expected_off = state->buf_user_offset - startoff;
2180         if (next_expected_off != entry->next_offset)
2181                 return -EINVAL;
2182
2183         if (*total < entry->next_offset)
2184                 return -EINVAL;
2185         *total -= entry->next_offset;
2186         return 0;
2187 }
2188
2189 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2190  * It might need more memory when copied to a 64 bit kernel in case
2191  * userspace is 32-bit. So, first task: find out how much memory is needed.
2192  *
2193  * Called before validation is performed.
2194  */
2195 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2196                                 struct ebt_entries_buf_state *state)
2197 {
2198         unsigned int size_remaining = size_user;
2199         int ret;
2200
2201         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2202                                         &size_remaining, state);
2203         if (ret < 0)
2204                 return ret;
2205
2206         if (size_remaining)
2207                 return -EINVAL;
2208
2209         return state->buf_kern_offset;
2210 }
2211
2212
2213 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2214                                              sockptr_t arg, unsigned int len)
2215 {
2216         struct compat_ebt_replace tmp;
2217         int i;
2218
2219         if (len < sizeof(tmp))
2220                 return -EINVAL;
2221
2222         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2223                 return -EFAULT;
2224
2225         if (len != sizeof(tmp) + tmp.entries_size)
2226                 return -EINVAL;
2227
2228         if (tmp.entries_size == 0)
2229                 return -EINVAL;
2230
2231         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2232                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2233                 return -ENOMEM;
2234         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2235                 return -ENOMEM;
2236
2237         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2238
2239         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2240         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2241                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2242
2243         repl->num_counters = tmp.num_counters;
2244         repl->counters = compat_ptr(tmp.counters);
2245         repl->entries = compat_ptr(tmp.entries);
2246         return 0;
2247 }
2248
2249 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2250 {
2251         int ret, i, countersize, size64;
2252         struct ebt_table_info *newinfo;
2253         struct ebt_replace tmp;
2254         struct ebt_entries_buf_state state;
2255         void *entries_tmp;
2256
2257         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2258         if (ret) {
2259                 /* try real handler in case userland supplied needed padding */
2260                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2261                         ret = 0;
2262                 return ret;
2263         }
2264
2265         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2266         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2267         if (!newinfo)
2268                 return -ENOMEM;
2269
2270         if (countersize)
2271                 memset(newinfo->counters, 0, countersize);
2272
2273         memset(&state, 0, sizeof(state));
2274
2275         newinfo->entries = vmalloc(tmp.entries_size);
2276         if (!newinfo->entries) {
2277                 ret = -ENOMEM;
2278                 goto free_newinfo;
2279         }
2280         if (copy_from_user(
2281            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2282                 ret = -EFAULT;
2283                 goto free_entries;
2284         }
2285
2286         entries_tmp = newinfo->entries;
2287
2288         xt_compat_lock(NFPROTO_BRIDGE);
2289
2290         ret = ebt_compat_init_offsets(tmp.nentries);
2291         if (ret < 0)
2292                 goto out_unlock;
2293
2294         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2295         if (ret < 0)
2296                 goto out_unlock;
2297
2298         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2299                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2300                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2301
2302         size64 = ret;
2303         newinfo->entries = vmalloc(size64);
2304         if (!newinfo->entries) {
2305                 vfree(entries_tmp);
2306                 ret = -ENOMEM;
2307                 goto out_unlock;
2308         }
2309
2310         memset(&state, 0, sizeof(state));
2311         state.buf_kern_start = newinfo->entries;
2312         state.buf_kern_len = size64;
2313
2314         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2315         if (WARN_ON(ret < 0)) {
2316                 vfree(entries_tmp);
2317                 goto out_unlock;
2318         }
2319
2320         vfree(entries_tmp);
2321         tmp.entries_size = size64;
2322
2323         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2324                 char __user *usrptr;
2325                 if (tmp.hook_entry[i]) {
2326                         unsigned int delta;
2327                         usrptr = (char __user *) tmp.hook_entry[i];
2328                         delta = usrptr - tmp.entries;
2329                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2330                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2331                 }
2332         }
2333
2334         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2335         xt_compat_unlock(NFPROTO_BRIDGE);
2336
2337         ret = do_replace_finish(net, &tmp, newinfo);
2338         if (ret == 0)
2339                 return ret;
2340 free_entries:
2341         vfree(newinfo->entries);
2342 free_newinfo:
2343         vfree(newinfo);
2344         return ret;
2345 out_unlock:
2346         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2347         xt_compat_unlock(NFPROTO_BRIDGE);
2348         goto free_entries;
2349 }
2350
2351 static int compat_update_counters(struct net *net, sockptr_t arg,
2352                                   unsigned int len)
2353 {
2354         struct compat_ebt_replace hlp;
2355
2356         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2357                 return -EFAULT;
2358
2359         /* try real handler in case userland supplied needed padding */
2360         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2361                 return update_counters(net, arg, len);
2362
2363         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2364                                   hlp.num_counters, len);
2365 }
2366
2367 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2368                 void __user *user, int *len)
2369 {
2370         int ret;
2371         struct compat_ebt_replace tmp;
2372         struct ebt_table *t;
2373         struct net *net = sock_net(sk);
2374
2375         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2376             *len != sizeof(struct compat_ebt_replace))
2377                 return -EINVAL;
2378
2379         if (copy_from_user(&tmp, user, sizeof(tmp)))
2380                 return -EFAULT;
2381
2382         tmp.name[sizeof(tmp.name) - 1] = '\0';
2383
2384         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2385         if (!t)
2386                 return ret;
2387
2388         xt_compat_lock(NFPROTO_BRIDGE);
2389         switch (cmd) {
2390         case EBT_SO_GET_INFO:
2391                 tmp.nentries = t->private->nentries;
2392                 ret = compat_table_info(t->private, &tmp);
2393                 if (ret)
2394                         goto out;
2395                 tmp.valid_hooks = t->valid_hooks;
2396
2397                 if (copy_to_user(user, &tmp, *len) != 0) {
2398                         ret = -EFAULT;
2399                         break;
2400                 }
2401                 ret = 0;
2402                 break;
2403         case EBT_SO_GET_INIT_INFO:
2404                 tmp.nentries = t->table->nentries;
2405                 tmp.entries_size = t->table->entries_size;
2406                 tmp.valid_hooks = t->table->valid_hooks;
2407
2408                 if (copy_to_user(user, &tmp, *len) != 0) {
2409                         ret = -EFAULT;
2410                         break;
2411                 }
2412                 ret = 0;
2413                 break;
2414         case EBT_SO_GET_ENTRIES:
2415         case EBT_SO_GET_INIT_ENTRIES:
2416                 /* try real handler first in case of userland-side padding.
2417                  * in case we are dealing with an 'ordinary' 32 bit binary
2418                  * without 64bit compatibility padding, this will fail right
2419                  * after copy_from_user when the *len argument is validated.
2420                  *
2421                  * the compat_ variant needs to do one pass over the kernel
2422                  * data set to adjust for size differences before it the check.
2423                  */
2424                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2425                         ret = 0;
2426                 else
2427                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2428                 break;
2429         default:
2430                 ret = -EINVAL;
2431         }
2432  out:
2433         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2434         xt_compat_unlock(NFPROTO_BRIDGE);
2435         mutex_unlock(&ebt_mutex);
2436         return ret;
2437 }
2438 #endif
2439
2440 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2441 {
2442         struct net *net = sock_net(sk);
2443         struct ebt_replace tmp;
2444         struct ebt_table *t;
2445         int ret;
2446
2447         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2448                 return -EPERM;
2449
2450 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2451         /* try real handler in case userland supplied needed padding */
2452         if (in_compat_syscall() &&
2453             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2454              *len != sizeof(tmp)))
2455                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2456 #endif
2457
2458         if (copy_from_user(&tmp, user, sizeof(tmp)))
2459                 return -EFAULT;
2460
2461         tmp.name[sizeof(tmp.name) - 1] = '\0';
2462
2463         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2464         if (!t)
2465                 return ret;
2466
2467         switch (cmd) {
2468         case EBT_SO_GET_INFO:
2469         case EBT_SO_GET_INIT_INFO:
2470                 if (*len != sizeof(struct ebt_replace)) {
2471                         ret = -EINVAL;
2472                         mutex_unlock(&ebt_mutex);
2473                         break;
2474                 }
2475                 if (cmd == EBT_SO_GET_INFO) {
2476                         tmp.nentries = t->private->nentries;
2477                         tmp.entries_size = t->private->entries_size;
2478                         tmp.valid_hooks = t->valid_hooks;
2479                 } else {
2480                         tmp.nentries = t->table->nentries;
2481                         tmp.entries_size = t->table->entries_size;
2482                         tmp.valid_hooks = t->table->valid_hooks;
2483                 }
2484                 mutex_unlock(&ebt_mutex);
2485                 if (copy_to_user(user, &tmp, *len) != 0) {
2486                         ret = -EFAULT;
2487                         break;
2488                 }
2489                 ret = 0;
2490                 break;
2491
2492         case EBT_SO_GET_ENTRIES:
2493         case EBT_SO_GET_INIT_ENTRIES:
2494                 ret = copy_everything_to_user(t, user, len, cmd);
2495                 mutex_unlock(&ebt_mutex);
2496                 break;
2497
2498         default:
2499                 mutex_unlock(&ebt_mutex);
2500                 ret = -EINVAL;
2501         }
2502
2503         return ret;
2504 }
2505
2506 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2507                 unsigned int len)
2508 {
2509         struct net *net = sock_net(sk);
2510         int ret;
2511
2512         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2513                 return -EPERM;
2514
2515         switch (cmd) {
2516         case EBT_SO_SET_ENTRIES:
2517 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2518                 if (in_compat_syscall())
2519                         ret = compat_do_replace(net, arg, len);
2520                 else
2521 #endif
2522                         ret = do_replace(net, arg, len);
2523                 break;
2524         case EBT_SO_SET_COUNTERS:
2525 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2526                 if (in_compat_syscall())
2527                         ret = compat_update_counters(net, arg, len);
2528                 else
2529 #endif
2530                         ret = update_counters(net, arg, len);
2531                 break;
2532         default:
2533                 ret = -EINVAL;
2534         }
2535         return ret;
2536 }
2537
2538 static struct nf_sockopt_ops ebt_sockopts = {
2539         .pf             = PF_INET,
2540         .set_optmin     = EBT_BASE_CTL,
2541         .set_optmax     = EBT_SO_SET_MAX + 1,
2542         .set            = do_ebt_set_ctl,
2543         .get_optmin     = EBT_BASE_CTL,
2544         .get_optmax     = EBT_SO_GET_MAX + 1,
2545         .get            = do_ebt_get_ctl,
2546         .owner          = THIS_MODULE,
2547 };
2548
2549 static int __net_init ebt_pernet_init(struct net *net)
2550 {
2551         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2552
2553         INIT_LIST_HEAD(&ebt_net->tables);
2554         return 0;
2555 }
2556
2557 static struct pernet_operations ebt_net_ops = {
2558         .init = ebt_pernet_init,
2559         .id   = &ebt_pernet_id,
2560         .size = sizeof(struct ebt_pernet),
2561 };
2562
2563 static int __init ebtables_init(void)
2564 {
2565         int ret;
2566
2567         ret = xt_register_target(&ebt_standard_target);
2568         if (ret < 0)
2569                 return ret;
2570         ret = nf_register_sockopt(&ebt_sockopts);
2571         if (ret < 0) {
2572                 xt_unregister_target(&ebt_standard_target);
2573                 return ret;
2574         }
2575
2576         ret = register_pernet_subsys(&ebt_net_ops);
2577         if (ret < 0) {
2578                 nf_unregister_sockopt(&ebt_sockopts);
2579                 xt_unregister_target(&ebt_standard_target);
2580                 return ret;
2581         }
2582
2583         return 0;
2584 }
2585
2586 static void ebtables_fini(void)
2587 {
2588         nf_unregister_sockopt(&ebt_sockopts);
2589         xt_unregister_target(&ebt_standard_target);
2590         unregister_pernet_subsys(&ebt_net_ops);
2591 }
2592
2593 EXPORT_SYMBOL(ebt_register_table);
2594 EXPORT_SYMBOL(ebt_unregister_table);
2595 EXPORT_SYMBOL(ebt_do_table);
2596 module_init(ebtables_init);
2597 module_exit(ebtables_fini);
2598 MODULE_LICENSE("GPL");