net/bridge/netfilter/ebtables.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ebtables
   4  *
   5  *  Author:
   6  *  Bart De Schuymer            <bdschuym@pandora.be>
   7  *
   8  *  ebtables.c,v 2.0, July, 2002
   9  *
  10  *  This code is strongly inspired by the iptables code which is
  11  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  12  */
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/kmod.h>
  15 #include <linux/module.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/netfilter/x_tables.h>
  18 #include <linux/netfilter_bridge/ebtables.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/mutex.h>
  21 #include <linux/slab.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/smp.h>
  24 #include <linux/cpumask.h>
  25 #include <linux/audit.h>
  26 #include <net/sock.h>
  27 #include <net/netns/generic.h>
  28 /* needed for logical [in,out]-dev filtering */
  29 #include "../br_private.h"
  30
  31 /* Each cpu has its own set of counters, so there is no need for write_lock in
  32  * the softirq
  33  * For reading or updating the counters, the user context needs to
  34  * get a write_lock
  35  */
  36
  37 /* The size of each set of counters is altered to get cache alignment */
  38 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  39 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  40 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  41                                  COUNTER_OFFSET(n) * cpu))
  42
  43 struct ebt_pernet {
  44         struct list_head tables;
  45 };
  46
  47 static unsigned int ebt_pernet_id __read_mostly;
  48 static DEFINE_MUTEX(ebt_mutex);
  49
  50 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  51 static void ebt_standard_compat_from_user(void *dst, const void *src)
  52 {
  53         int v = *(compat_int_t *)src;
  54
  55         if (v >= 0)
  56                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  57         memcpy(dst, &v, sizeof(v));
  58 }
  59
  60 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  61 {
  62         compat_int_t cv = *(int *)src;
  63
  64         if (cv >= 0)
  65                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  66         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  67 }
  68 #endif
  69
  70
  71 static struct xt_target ebt_standard_target = {
  72         .name       = "standard",
  73         .revision   = 0,
  74         .family     = NFPROTO_BRIDGE,
  75         .targetsize = sizeof(int),
  76 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  77         .compatsize = sizeof(compat_int_t),
  78         .compat_from_user = ebt_standard_compat_from_user,
  79         .compat_to_user =  ebt_standard_compat_to_user,
  80 #endif
  81 };
  82
  83 static inline int
  84 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  85                struct xt_action_param *par)
  86 {
  87         par->target   = w->u.watcher;
  88         par->targinfo = w->data;
  89         w->u.watcher->target(skb, par);
  90         /* watchers don't give a verdict */
  91         return 0;
  92 }
  93
  94 static inline int
  95 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
  96              struct xt_action_param *par)
  97 {
  98         par->match     = m->u.match;
  99         par->matchinfo = m->data;
 100         return !m->u.match->match(skb, par);
 101 }
 102
 103 static inline int
 104 ebt_dev_check(const char *entry, const struct net_device *device)
 105 {
 106         int i = 0;
 107         const char *devname;
 108
 109         if (*entry == '\0')
 110                 return 0;
 111         if (!device)
 112                 return 1;
 113         devname = device->name;
 114         /* 1 is the wildcard token */
 115         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 116                 i++;
 117         return devname[i] != entry[i] && entry[i] != 1;
 118 }
 119
 120 /* process standard matches */
 121 static inline int
 122 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 123                 const struct net_device *in, const struct net_device *out)
 124 {
 125         const struct ethhdr *h = eth_hdr(skb);
 126         const struct net_bridge_port *p;
 127         __be16 ethproto;
 128
 129         if (skb_vlan_tag_present(skb))
 130                 ethproto = htons(ETH_P_8021Q);
 131         else
 132                 ethproto = h->h_proto;
 133
 134         if (e->bitmask & EBT_802_3) {
 135                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 136                         return 1;
 137         } else if (!(e->bitmask & EBT_NOPROTO) &&
 138                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 139                 return 1;
 140
 141         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 142                 return 1;
 143         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 144                 return 1;
 145         /* rcu_read_lock()ed by nf_hook_thresh */
 146         if (in && (p = br_port_get_rcu(in)) != NULL &&
 147             NF_INVF(e, EBT_ILOGICALIN,
 148                     ebt_dev_check(e->logical_in, p->br->dev)))
 149                 return 1;
 150         if (out && (p = br_port_get_rcu(out)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALOUT,
 152                     ebt_dev_check(e->logical_out, p->br->dev)))
 153                 return 1;
 154
 155         if (e->bitmask & EBT_SOURCEMAC) {
 156                 if (NF_INVF(e, EBT_ISOURCE,
 157                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 158                                                      e->sourcemsk)))
 159                         return 1;
 160         }
 161         if (e->bitmask & EBT_DESTMAC) {
 162                 if (NF_INVF(e, EBT_IDEST,
 163                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 164                                                      e->destmsk)))
 165                         return 1;
 166         }
 167         return 0;
 168 }
 169
 170 static inline
 171 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 172 {
 173         return (void *)entry + entry->next_offset;
 174 }
 175
 176 static inline const struct ebt_entry_target *
 177 ebt_get_target_c(const struct ebt_entry *e)
 178 {
 179         return ebt_get_target((struct ebt_entry *)e);
 180 }
 181
 182 /* Do some firewalling */
 183 unsigned int ebt_do_table(struct sk_buff *skb,
 184                           const struct nf_hook_state *state,
 185                           struct ebt_table *table)
 186 {
 187         unsigned int hook = state->hook;
 188         int i, nentries;
 189         struct ebt_entry *point;
 190         struct ebt_counter *counter_base, *cb_base;
 191         const struct ebt_entry_target *t;
 192         int verdict, sp = 0;
 193         struct ebt_chainstack *cs;
 194         struct ebt_entries *chaininfo;
 195         const char *base;
 196         const struct ebt_table_info *private;
 197         struct xt_action_param acpar;
 198
 199         acpar.state   = state;
 200         acpar.hotdrop = false;
 201
 202         read_lock_bh(&table->lock);
 203         private = table->private;
 204         cb_base = COUNTER_BASE(private->counters, private->nentries,
 205            smp_processor_id());
 206         if (private->chainstack)
 207                 cs = private->chainstack[smp_processor_id()];
 208         else
 209                 cs = NULL;
 210         chaininfo = private->hook_entry[hook];
 211         nentries = private->hook_entry[hook]->nentries;
 212         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 213         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 214         /* base for chain jumps */
 215         base = private->entries;
 216         i = 0;
 217         while (i < nentries) {
 218                 if (ebt_basic_match(point, skb, state->in, state->out))
 219                         goto letscontinue;
 220
 221                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 222                         goto letscontinue;
 223                 if (acpar.hotdrop) {
 224                         read_unlock_bh(&table->lock);
 225                         return NF_DROP;
 226                 }
 227
 228                 ADD_COUNTER(*(counter_base + i), skb->len, 1);
 229
 230                 /* these should only watch: not modify, nor tell us
 231                  * what to do with the packet
 232                  */
 233                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 234
 235                 t = ebt_get_target_c(point);
 236                 /* standard target */
 237                 if (!t->u.target->target)
 238                         verdict = ((struct ebt_standard_target *)t)->verdict;
 239                 else {
 240                         acpar.target   = t->u.target;
 241                         acpar.targinfo = t->data;
 242                         verdict = t->u.target->target(skb, &acpar);
 243                 }
 244                 if (verdict == EBT_ACCEPT) {
 245                         read_unlock_bh(&table->lock);
 246                         return NF_ACCEPT;
 247                 }
 248                 if (verdict == EBT_DROP) {
 249                         read_unlock_bh(&table->lock);
 250                         return NF_DROP;
 251                 }
 252                 if (verdict == EBT_RETURN) {
 253 letsreturn:
 254                         if (WARN(sp == 0, "RETURN on base chain")) {
 255                                 /* act like this is EBT_CONTINUE */
 256                                 goto letscontinue;
 257                         }
 258
 259                         sp--;
 260                         /* put all the local variables right */
 261                         i = cs[sp].n;
 262                         chaininfo = cs[sp].chaininfo;
 263                         nentries = chaininfo->nentries;
 264                         point = cs[sp].e;
 265                         counter_base = cb_base +
 266                            chaininfo->counter_offset;
 267                         continue;
 268                 }
 269                 if (verdict == EBT_CONTINUE)
 270                         goto letscontinue;
 271
 272                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 273                         read_unlock_bh(&table->lock);
 274                         return NF_DROP;
 275                 }
 276
 277                 /* jump to a udc */
 278                 cs[sp].n = i + 1;
 279                 cs[sp].chaininfo = chaininfo;
 280                 cs[sp].e = ebt_next_entry(point);
 281                 i = 0;
 282                 chaininfo = (struct ebt_entries *) (base + verdict);
 283
 284                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 285                         read_unlock_bh(&table->lock);
 286                         return NF_DROP;
 287                 }
 288
 289                 nentries = chaininfo->nentries;
 290                 point = (struct ebt_entry *)chaininfo->data;
 291                 counter_base = cb_base + chaininfo->counter_offset;
 292                 sp++;
 293                 continue;
 294 letscontinue:
 295                 point = ebt_next_entry(point);
 296                 i++;
 297         }
 298
 299         /* I actually like this :) */
 300         if (chaininfo->policy == EBT_RETURN)
 301                 goto letsreturn;
 302         if (chaininfo->policy == EBT_ACCEPT) {
 303                 read_unlock_bh(&table->lock);
 304                 return NF_ACCEPT;
 305         }
 306         read_unlock_bh(&table->lock);
 307         return NF_DROP;
 308 }
 309
 310 /* If it succeeds, returns element and locks mutex */
 311 static inline void *
 312 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 313                         struct mutex *mutex)
 314 {
 315         struct {
 316                 struct list_head list;
 317                 char name[EBT_FUNCTION_MAXNAMELEN];
 318         } *e;
 319
 320         mutex_lock(mutex);
 321         list_for_each_entry(e, head, list) {
 322                 if (strcmp(e->name, name) == 0)
 323                         return e;
 324         }
 325         *error = -ENOENT;
 326         mutex_unlock(mutex);
 327         return NULL;
 328 }
 329
 330 static void *
 331 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 332                  int *error, struct mutex *mutex)
 333 {
 334         return try_then_request_module(
 335                         find_inlist_lock_noload(head, name, error, mutex),
 336                         "%s%s", prefix, name);
 337 }
 338
 339 static inline struct ebt_table *
 340 find_table_lock(struct net *net, const char *name, int *error,
 341                 struct mutex *mutex)
 342 {
 343         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
 344
 345         return find_inlist_lock(&ebt_net->tables, name,
 346                                 "ebtable_", error, mutex);
 347 }
 348
 349 static inline void ebt_free_table_info(struct ebt_table_info *info)
 350 {
 351         int i;
 352
 353         if (info->chainstack) {
 354                 for_each_possible_cpu(i)
 355                         vfree(info->chainstack[i]);
 356                 vfree(info->chainstack);
 357         }
 358 }
 359 static inline int
 360 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 361                 unsigned int *cnt)
 362 {
 363         const struct ebt_entry *e = par->entryinfo;
 364         struct xt_match *match;
 365         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 366         int ret;
 367
 368         if (left < sizeof(struct ebt_entry_match) ||
 369             left - sizeof(struct ebt_entry_match) < m->match_size)
 370                 return -EINVAL;
 371
 372         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 373         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 374                 if (!IS_ERR(match))
 375                         module_put(match->me);
 376                 request_module("ebt_%s", m->u.name);
 377                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 378         }
 379         if (IS_ERR(match))
 380                 return PTR_ERR(match);
 381         m->u.match = match;
 382
 383         par->match     = match;
 384         par->matchinfo = m->data;
 385         ret = xt_check_match(par, m->match_size,
 386               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 387         if (ret < 0) {
 388                 module_put(match->me);
 389                 return ret;
 390         }
 391
 392         (*cnt)++;
 393         return 0;
 394 }
 395
 396 static inline int
 397 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 398                   unsigned int *cnt)
 399 {
 400         const struct ebt_entry *e = par->entryinfo;
 401         struct xt_target *watcher;
 402         size_t left = ((char *)e + e->target_offset) - (char *)w;
 403         int ret;
 404
 405         if (left < sizeof(struct ebt_entry_watcher) ||
 406            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 407                 return -EINVAL;
 408
 409         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 410         if (IS_ERR(watcher))
 411                 return PTR_ERR(watcher);
 412
 413         if (watcher->family != NFPROTO_BRIDGE) {
 414                 module_put(watcher->me);
 415                 return -ENOENT;
 416         }
 417
 418         w->u.watcher = watcher;
 419
 420         par->target   = watcher;
 421         par->targinfo = w->data;
 422         ret = xt_check_target(par, w->watcher_size,
 423               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 424         if (ret < 0) {
 425                 module_put(watcher->me);
 426                 return ret;
 427         }
 428
 429         (*cnt)++;
 430         return 0;
 431 }
 432
 433 static int ebt_verify_pointers(const struct ebt_replace *repl,
 434                                struct ebt_table_info *newinfo)
 435 {
 436         unsigned int limit = repl->entries_size;
 437         unsigned int valid_hooks = repl->valid_hooks;
 438         unsigned int offset = 0;
 439         int i;
 440
 441         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 442                 newinfo->hook_entry[i] = NULL;
 443
 444         newinfo->entries_size = repl->entries_size;
 445         newinfo->nentries = repl->nentries;
 446
 447         while (offset < limit) {
 448                 size_t left = limit - offset;
 449                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 450
 451                 if (left < sizeof(unsigned int))
 452                         break;
 453
 454                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 455                         if ((valid_hooks & (1 << i)) == 0)
 456                                 continue;
 457                         if ((char __user *)repl->hook_entry[i] ==
 458                              repl->entries + offset)
 459                                 break;
 460                 }
 461
 462                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 463                         if (e->bitmask != 0) {
 464                                 /* we make userspace set this right,
 465                                  * so there is no misunderstanding
 466                                  */
 467                                 return -EINVAL;
 468                         }
 469                         if (i != NF_BR_NUMHOOKS)
 470                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 471                         if (left < sizeof(struct ebt_entries))
 472                                 break;
 473                         offset += sizeof(struct ebt_entries);
 474                 } else {
 475                         if (left < sizeof(struct ebt_entry))
 476                                 break;
 477                         if (left < e->next_offset)
 478                                 break;
 479                         if (e->next_offset < sizeof(struct ebt_entry))
 480                                 return -EINVAL;
 481                         offset += e->next_offset;
 482                 }
 483         }
 484         if (offset != limit)
 485                 return -EINVAL;
 486
 487         /* check if all valid hooks have a chain */
 488         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 489                 if (!newinfo->hook_entry[i] &&
 490                    (valid_hooks & (1 << i)))
 491                         return -EINVAL;
 492         }
 493         return 0;
 494 }
 495
 496 /* this one is very careful, as it is the first function
 497  * to parse the userspace data
 498  */
 499 static inline int
 500 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 501                                const struct ebt_table_info *newinfo,
 502                                unsigned int *n, unsigned int *cnt,
 503                                unsigned int *totalcnt, unsigned int *udc_cnt)
 504 {
 505         int i;
 506
 507         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 508                 if ((void *)e == (void *)newinfo->hook_entry[i])
 509                         break;
 510         }
 511         /* beginning of a new chain
 512          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 513          */
 514         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 515                 /* this checks if the previous chain has as many entries
 516                  * as it said it has
 517                  */
 518                 if (*n != *cnt)
 519                         return -EINVAL;
 520
 521                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 522                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 523                         /* only RETURN from udc */
 524                         if (i != NF_BR_NUMHOOKS ||
 525                            ((struct ebt_entries *)e)->policy != EBT_RETURN)
 526                                 return -EINVAL;
 527                 }
 528                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 529                         (*udc_cnt)++;
 530                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
 531                         return -EINVAL;
 532                 *n = ((struct ebt_entries *)e)->nentries;
 533                 *cnt = 0;
 534                 return 0;
 535         }
 536         /* a plain old entry, heh */
 537         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 538            e->watchers_offset > e->target_offset ||
 539            e->target_offset >= e->next_offset)
 540                 return -EINVAL;
 541
 542         /* this is not checked anywhere else */
 543         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
 544                 return -EINVAL;
 545
 546         (*cnt)++;
 547         (*totalcnt)++;
 548         return 0;
 549 }
 550
 551 struct ebt_cl_stack {
 552         struct ebt_chainstack cs;
 553         int from;
 554         unsigned int hookmask;
 555 };
 556
 557 /* We need these positions to check that the jumps to a different part of the
 558  * entries is a jump to the beginning of a new chain.
 559  */
 560 static inline int
 561 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 562                       unsigned int *n, struct ebt_cl_stack *udc)
 563 {
 564         int i;
 565
 566         /* we're only interested in chain starts */
 567         if (e->bitmask)
 568                 return 0;
 569         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 570                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 571                         break;
 572         }
 573         /* only care about udc */
 574         if (i != NF_BR_NUMHOOKS)
 575                 return 0;
 576
 577         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 578         /* these initialisations are depended on later in check_chainloops() */
 579         udc[*n].cs.n = 0;
 580         udc[*n].hookmask = 0;
 581
 582         (*n)++;
 583         return 0;
 584 }
 585
 586 static inline int
 587 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 588 {
 589         struct xt_mtdtor_param par;
 590
 591         if (i && (*i)-- == 0)
 592                 return 1;
 593
 594         par.net       = net;
 595         par.match     = m->u.match;
 596         par.matchinfo = m->data;
 597         par.family    = NFPROTO_BRIDGE;
 598         if (par.match->destroy != NULL)
 599                 par.match->destroy(&par);
 600         module_put(par.match->me);
 601         return 0;
 602 }
 603
 604 static inline int
 605 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 606 {
 607         struct xt_tgdtor_param par;
 608
 609         if (i && (*i)-- == 0)
 610                 return 1;
 611
 612         par.net      = net;
 613         par.target   = w->u.watcher;
 614         par.targinfo = w->data;
 615         par.family   = NFPROTO_BRIDGE;
 616         if (par.target->destroy != NULL)
 617                 par.target->destroy(&par);
 618         module_put(par.target->me);
 619         return 0;
 620 }
 621
 622 static inline int
 623 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 624 {
 625         struct xt_tgdtor_param par;
 626         struct ebt_entry_target *t;
 627
 628         if (e->bitmask == 0)
 629                 return 0;
 630         /* we're done */
 631         if (cnt && (*cnt)-- == 0)
 632                 return 1;
 633         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 634         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 635         t = ebt_get_target(e);
 636
 637         par.net      = net;
 638         par.target   = t->u.target;
 639         par.targinfo = t->data;
 640         par.family   = NFPROTO_BRIDGE;
 641         if (par.target->destroy != NULL)
 642                 par.target->destroy(&par);
 643         module_put(par.target->me);
 644         return 0;
 645 }
 646
 647 static inline int
 648 ebt_check_entry(struct ebt_entry *e, struct net *net,
 649                 const struct ebt_table_info *newinfo,
 650                 const char *name, unsigned int *cnt,
 651                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 652 {
 653         struct ebt_entry_target *t;
 654         struct xt_target *target;
 655         unsigned int i, j, hook = 0, hookmask = 0;
 656         size_t gap;
 657         int ret;
 658         struct xt_mtchk_param mtpar;
 659         struct xt_tgchk_param tgpar;
 660
 661         /* don't mess with the struct ebt_entries */
 662         if (e->bitmask == 0)
 663                 return 0;
 664
 665         if (e->bitmask & ~EBT_F_MASK)
 666                 return -EINVAL;
 667
 668         if (e->invflags & ~EBT_INV_MASK)
 669                 return -EINVAL;
 670
 671         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
 672                 return -EINVAL;
 673
 674         /* what hook do we belong to? */
 675         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 676                 if (!newinfo->hook_entry[i])
 677                         continue;
 678                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 679                         hook = i;
 680                 else
 681                         break;
 682         }
 683         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 684          * a base chain
 685          */
 686         if (i < NF_BR_NUMHOOKS)
 687                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 688         else {
 689                 for (i = 0; i < udc_cnt; i++)
 690                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 691                                 break;
 692                 if (i == 0)
 693                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 694                 else
 695                         hookmask = cl_s[i - 1].hookmask;
 696         }
 697         i = 0;
 698
 699         memset(&mtpar, 0, sizeof(mtpar));
 700         memset(&tgpar, 0, sizeof(tgpar));
 701         mtpar.net       = tgpar.net       = net;
 702         mtpar.table     = tgpar.table     = name;
 703         mtpar.entryinfo = tgpar.entryinfo = e;
 704         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 705         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 706         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 707         if (ret != 0)
 708                 goto cleanup_matches;
 709         j = 0;
 710         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 711         if (ret != 0)
 712                 goto cleanup_watchers;
 713         t = ebt_get_target(e);
 714         gap = e->next_offset - e->target_offset;
 715
 716         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 717         if (IS_ERR(target)) {
 718                 ret = PTR_ERR(target);
 719                 goto cleanup_watchers;
 720         }
 721
 722         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 723         if (target->family != NFPROTO_BRIDGE) {
 724                 module_put(target->me);
 725                 ret = -ENOENT;
 726                 goto cleanup_watchers;
 727         }
 728
 729         t->u.target = target;
 730         if (t->u.target == &ebt_standard_target) {
 731                 if (gap < sizeof(struct ebt_standard_target)) {
 732                         ret = -EFAULT;
 733                         goto cleanup_watchers;
 734                 }
 735                 if (((struct ebt_standard_target *)t)->verdict <
 736                    -NUM_STANDARD_TARGETS) {
 737                         ret = -EFAULT;
 738                         goto cleanup_watchers;
 739                 }
 740         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 741                 module_put(t->u.target->me);
 742                 ret = -EFAULT;
 743                 goto cleanup_watchers;
 744         }
 745
 746         tgpar.target   = target;
 747         tgpar.targinfo = t->data;
 748         ret = xt_check_target(&tgpar, t->target_size,
 749               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 750         if (ret < 0) {
 751                 module_put(target->me);
 752                 goto cleanup_watchers;
 753         }
 754         (*cnt)++;
 755         return 0;
 756 cleanup_watchers:
 757         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 758 cleanup_matches:
 759         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 760         return ret;
 761 }
 762
 763 /* checks for loops and sets the hook mask for udc
 764  * the hook mask for udc tells us from which base chains the udc can be
 765  * accessed. This mask is a parameter to the check() functions of the extensions
 766  */
 767 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 768                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 769 {
 770         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 771         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 772         const struct ebt_entry_target *t;
 773
 774         while (pos < nentries || chain_nr != -1) {
 775                 /* end of udc, go back one 'recursion' step */
 776                 if (pos == nentries) {
 777                         /* put back values of the time when this chain was called */
 778                         e = cl_s[chain_nr].cs.e;
 779                         if (cl_s[chain_nr].from != -1)
 780                                 nentries =
 781                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 782                         else
 783                                 nentries = chain->nentries;
 784                         pos = cl_s[chain_nr].cs.n;
 785                         /* make sure we won't see a loop that isn't one */
 786                         cl_s[chain_nr].cs.n = 0;
 787                         chain_nr = cl_s[chain_nr].from;
 788                         if (pos == nentries)
 789                                 continue;
 790                 }
 791                 t = ebt_get_target_c(e);
 792                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 793                         goto letscontinue;
 794                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 795                    e->next_offset)
 796                         return -1;
 797
 798                 verdict = ((struct ebt_standard_target *)t)->verdict;
 799                 if (verdict >= 0) { /* jump to another chain */
 800                         struct ebt_entries *hlp2 =
 801                            (struct ebt_entries *)(base + verdict);
 802                         for (i = 0; i < udc_cnt; i++)
 803                                 if (hlp2 == cl_s[i].cs.chaininfo)
 804                                         break;
 805                         /* bad destination or loop */
 806                         if (i == udc_cnt)
 807                                 return -1;
 808
 809                         if (cl_s[i].cs.n)
 810                                 return -1;
 811
 812                         if (cl_s[i].hookmask & (1 << hooknr))
 813                                 goto letscontinue;
 814                         /* this can't be 0, so the loop test is correct */
 815                         cl_s[i].cs.n = pos + 1;
 816                         pos = 0;
 817                         cl_s[i].cs.e = ebt_next_entry(e);
 818                         e = (struct ebt_entry *)(hlp2->data);
 819                         nentries = hlp2->nentries;
 820                         cl_s[i].from = chain_nr;
 821                         chain_nr = i;
 822                         /* this udc is accessible from the base chain for hooknr */
 823                         cl_s[i].hookmask |= (1 << hooknr);
 824                         continue;
 825                 }
 826 letscontinue:
 827                 e = ebt_next_entry(e);
 828                 pos++;
 829         }
 830         return 0;
 831 }
 832
 833 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 834 static int translate_table(struct net *net, const char *name,
 835                            struct ebt_table_info *newinfo)
 836 {
 837         unsigned int i, j, k, udc_cnt;
 838         int ret;
 839         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 840
 841         i = 0;
 842         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 843                 i++;
 844         if (i == NF_BR_NUMHOOKS)
 845                 return -EINVAL;
 846
 847         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
 848                 return -EINVAL;
 849
 850         /* make sure chains are ordered after each other in same order
 851          * as their corresponding hooks
 852          */
 853         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 854                 if (!newinfo->hook_entry[j])
 855                         continue;
 856                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
 857                         return -EINVAL;
 858
 859                 i = j;
 860         }
 861
 862         /* do some early checkings and initialize some things */
 863         i = 0; /* holds the expected nr. of entries for the chain */
 864         j = 0; /* holds the up to now counted entries for the chain */
 865         k = 0; /* holds the total nr. of entries, should equal
 866                 * newinfo->nentries afterwards
 867                 */
 868         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 869         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 870            ebt_check_entry_size_and_hooks, newinfo,
 871            &i, &j, &k, &udc_cnt);
 872
 873         if (ret != 0)
 874                 return ret;
 875
 876         if (i != j)
 877                 return -EINVAL;
 878
 879         if (k != newinfo->nentries)
 880                 return -EINVAL;
 881
 882         /* get the location of the udc, put them in an array
 883          * while we're at it, allocate the chainstack
 884          */
 885         if (udc_cnt) {
 886                 /* this will get free'd in do_replace()/ebt_register_table()
 887                  * if an error occurs
 888                  */
 889                 newinfo->chainstack =
 890                         vmalloc(array_size(nr_cpu_ids,
 891                                            sizeof(*(newinfo->chainstack))));
 892                 if (!newinfo->chainstack)
 893                         return -ENOMEM;
 894                 for_each_possible_cpu(i) {
 895                         newinfo->chainstack[i] =
 896                           vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 897                         if (!newinfo->chainstack[i]) {
 898                                 while (i)
 899                                         vfree(newinfo->chainstack[--i]);
 900                                 vfree(newinfo->chainstack);
 901                                 newinfo->chainstack = NULL;
 902                                 return -ENOMEM;
 903                         }
 904                 }
 905
 906                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 907                 if (!cl_s)
 908                         return -ENOMEM;
 909                 i = 0; /* the i'th udc */
 910                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 911                    ebt_get_udc_positions, newinfo, &i, cl_s);
 912                 /* sanity check */
 913                 if (i != udc_cnt) {
 914                         vfree(cl_s);
 915                         return -EFAULT;
 916                 }
 917         }
 918
 919         /* Check for loops */
 920         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 921                 if (newinfo->hook_entry[i])
 922                         if (check_chainloops(newinfo->hook_entry[i],
 923                            cl_s, udc_cnt, i, newinfo->entries)) {
 924                                 vfree(cl_s);
 925                                 return -EINVAL;
 926                         }
 927
 928         /* we now know the following (along with E=mc²):
 929          *  - the nr of entries in each chain is right
 930          *  - the size of the allocated space is right
 931          *  - all valid hooks have a corresponding chain
 932          *  - there are no loops
 933          *  - wrong data can still be on the level of a single entry
 934          *  - could be there are jumps to places that are not the
 935          *    beginning of a chain. This can only occur in chains that
 936          *    are not accessible from any base chains, so we don't care.
 937          */
 938
 939         /* used to know what we need to clean up if something goes wrong */
 940         i = 0;
 941         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 942            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 943         if (ret != 0) {
 944                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 945                                   ebt_cleanup_entry, net, &i);
 946         }
 947         vfree(cl_s);
 948         return ret;
 949 }
 950
 951 /* called under write_lock */
 952 static void get_counters(const struct ebt_counter *oldcounters,
 953                          struct ebt_counter *counters, unsigned int nentries)
 954 {
 955         int i, cpu;
 956         struct ebt_counter *counter_base;
 957
 958         /* counters of cpu 0 */
 959         memcpy(counters, oldcounters,
 960                sizeof(struct ebt_counter) * nentries);
 961
 962         /* add other counters to those of cpu 0 */
 963         for_each_possible_cpu(cpu) {
 964                 if (cpu == 0)
 965                         continue;
 966                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 967                 for (i = 0; i < nentries; i++)
 968                         ADD_COUNTER(counters[i], counter_base[i].bcnt,
 969                                     counter_base[i].pcnt);
 970         }
 971 }
 972
 973 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 974                               struct ebt_table_info *newinfo)
 975 {
 976         int ret;
 977         struct ebt_counter *counterstmp = NULL;
 978         /* used to be able to unlock earlier */
 979         struct ebt_table_info *table;
 980         struct ebt_table *t;
 981
 982         /* the user wants counters back
 983          * the check on the size is done later, when we have the lock
 984          */
 985         if (repl->num_counters) {
 986                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 987                 counterstmp = vmalloc(size);
 988                 if (!counterstmp)
 989                         return -ENOMEM;
 990         }
 991
 992         newinfo->chainstack = NULL;
 993         ret = ebt_verify_pointers(repl, newinfo);
 994         if (ret != 0)
 995                 goto free_counterstmp;
 996
 997         ret = translate_table(net, repl->name, newinfo);
 998
 999         if (ret != 0)
1000                 goto free_counterstmp;
1001
1002         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1003         if (!t) {
1004                 ret = -ENOENT;
1005                 goto free_iterate;
1006         }
1007
1008         /* the table doesn't like it */
1009         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1010                 goto free_unlock;
1011
1012         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1013                 ret = -EINVAL;
1014                 goto free_unlock;
1015         }
1016
1017         /* we have the mutex lock, so no danger in reading this pointer */
1018         table = t->private;
1019         /* make sure the table can only be rmmod'ed if it contains no rules */
1020         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1021                 ret = -ENOENT;
1022                 goto free_unlock;
1023         } else if (table->nentries && !newinfo->nentries)
1024                 module_put(t->me);
1025         /* we need an atomic snapshot of the counters */
1026         write_lock_bh(&t->lock);
1027         if (repl->num_counters)
1028                 get_counters(t->private->counters, counterstmp,
1029                    t->private->nentries);
1030
1031         t->private = newinfo;
1032         write_unlock_bh(&t->lock);
1033         mutex_unlock(&ebt_mutex);
1034         /* so, a user can change the chains while having messed up her counter
1035          * allocation. Only reason why this is done is because this way the lock
1036          * is held only once, while this doesn't bring the kernel into a
1037          * dangerous state.
1038          */
1039         if (repl->num_counters &&
1040            copy_to_user(repl->counters, counterstmp,
1041            repl->num_counters * sizeof(struct ebt_counter))) {
1042                 /* Silent error, can't fail, new table is already in place */
1043                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1044         }
1045
1046         /* decrease module count and free resources */
1047         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1048                           ebt_cleanup_entry, net, NULL);
1049
1050         vfree(table->entries);
1051         ebt_free_table_info(table);
1052         vfree(table);
1053         vfree(counterstmp);
1054
1055         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1056                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1057         return ret;
1058
1059 free_unlock:
1060         mutex_unlock(&ebt_mutex);
1061 free_iterate:
1062         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1063                           ebt_cleanup_entry, net, NULL);
1064 free_counterstmp:
1065         vfree(counterstmp);
1066         /* can be initialized in translate_table() */
1067         ebt_free_table_info(newinfo);
1068         return ret;
1069 }
1070
1071 /* replace the table */
1072 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1073 {
1074         int ret, countersize;
1075         struct ebt_table_info *newinfo;
1076         struct ebt_replace tmp;
1077
1078         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1079                 return -EFAULT;
1080
1081         if (len != sizeof(tmp) + tmp.entries_size)
1082                 return -EINVAL;
1083
1084         if (tmp.entries_size == 0)
1085                 return -EINVAL;
1086
1087         /* overflow check */
1088         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1089                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1090                 return -ENOMEM;
1091         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1092                 return -ENOMEM;
1093
1094         tmp.name[sizeof(tmp.name) - 1] = 0;
1095
1096         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1097         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1098         if (!newinfo)
1099                 return -ENOMEM;
1100
1101         if (countersize)
1102                 memset(newinfo->counters, 0, countersize);
1103
1104         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1105         if (!newinfo->entries) {
1106                 ret = -ENOMEM;
1107                 goto free_newinfo;
1108         }
1109         if (copy_from_user(
1110            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1111                 ret = -EFAULT;
1112                 goto free_entries;
1113         }
1114
1115         ret = do_replace_finish(net, &tmp, newinfo);
1116         if (ret == 0)
1117                 return ret;
1118 free_entries:
1119         vfree(newinfo->entries);
1120 free_newinfo:
1121         vfree(newinfo);
1122         return ret;
1123 }
1124
1125 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1126 {
1127         mutex_lock(&ebt_mutex);
1128         list_del(&table->list);
1129         mutex_unlock(&ebt_mutex);
1130         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1131                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1132         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1133                           ebt_cleanup_entry, net, NULL);
1134         if (table->private->nentries)
1135                 module_put(table->me);
1136         vfree(table->private->entries);
1137         ebt_free_table_info(table->private);
1138         vfree(table->private);
1139         kfree(table->ops);
1140         kfree(table);
1141 }
1142
1143 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1144                        const struct nf_hook_ops *template_ops)
1145 {
1146         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1147         struct ebt_table_info *newinfo;
1148         struct ebt_table *t, *table;
1149         struct nf_hook_ops *ops;
1150         unsigned int num_ops;
1151         struct ebt_replace_kernel *repl;
1152         int ret, i, countersize;
1153         void *p;
1154
1155         if (input_table == NULL || (repl = input_table->table) == NULL ||
1156             repl->entries == NULL || repl->entries_size == 0 ||
1157             repl->counters != NULL || input_table->private != NULL)
1158                 return -EINVAL;
1159
1160         /* Don't add one table to multiple lists. */
1161         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1162         if (!table) {
1163                 ret = -ENOMEM;
1164                 goto out;
1165         }
1166
1167         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1168         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1169         ret = -ENOMEM;
1170         if (!newinfo)
1171                 goto free_table;
1172
1173         p = vmalloc(repl->entries_size);
1174         if (!p)
1175                 goto free_newinfo;
1176
1177         memcpy(p, repl->entries, repl->entries_size);
1178         newinfo->entries = p;
1179
1180         newinfo->entries_size = repl->entries_size;
1181         newinfo->nentries = repl->nentries;
1182
1183         if (countersize)
1184                 memset(newinfo->counters, 0, countersize);
1185
1186         /* fill in newinfo and parse the entries */
1187         newinfo->chainstack = NULL;
1188         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1189                 if ((repl->valid_hooks & (1 << i)) == 0)
1190                         newinfo->hook_entry[i] = NULL;
1191                 else
1192                         newinfo->hook_entry[i] = p +
1193                                 ((char *)repl->hook_entry[i] - repl->entries);
1194         }
1195         ret = translate_table(net, repl->name, newinfo);
1196         if (ret != 0)
1197                 goto free_chainstack;
1198
1199         if (table->check && table->check(newinfo, table->valid_hooks)) {
1200                 ret = -EINVAL;
1201                 goto free_chainstack;
1202         }
1203
1204         table->private = newinfo;
1205         rwlock_init(&table->lock);
1206         mutex_lock(&ebt_mutex);
1207         list_for_each_entry(t, &ebt_net->tables, list) {
1208                 if (strcmp(t->name, table->name) == 0) {
1209                         ret = -EEXIST;
1210                         goto free_unlock;
1211                 }
1212         }
1213
1214         /* Hold a reference count if the chains aren't empty */
1215         if (newinfo->nentries && !try_module_get(table->me)) {
1216                 ret = -ENOENT;
1217                 goto free_unlock;
1218         }
1219
1220         num_ops = hweight32(table->valid_hooks);
1221         if (num_ops == 0) {
1222                 ret = -EINVAL;
1223                 goto free_unlock;
1224         }
1225
1226         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1227         if (!ops) {
1228                 ret = -ENOMEM;
1229                 if (newinfo->nentries)
1230                         module_put(table->me);
1231                 goto free_unlock;
1232         }
1233
1234         for (i = 0; i < num_ops; i++)
1235                 ops[i].priv = table;
1236
1237         list_add(&table->list, &ebt_net->tables);
1238         mutex_unlock(&ebt_mutex);
1239
1240         table->ops = ops;
1241         ret = nf_register_net_hooks(net, ops, num_ops);
1242         if (ret)
1243                 __ebt_unregister_table(net, table);
1244
1245         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1246                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1247         return ret;
1248 free_unlock:
1249         mutex_unlock(&ebt_mutex);
1250 free_chainstack:
1251         ebt_free_table_info(newinfo);
1252         vfree(newinfo->entries);
1253 free_newinfo:
1254         vfree(newinfo);
1255 free_table:
1256         kfree(table);
1257 out:
1258         return ret;
1259 }
1260
1261 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1262 {
1263         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1264         struct ebt_table *t;
1265
1266         mutex_lock(&ebt_mutex);
1267
1268         list_for_each_entry(t, &ebt_net->tables, list) {
1269                 if (strcmp(t->name, name) == 0) {
1270                         mutex_unlock(&ebt_mutex);
1271                         return t;
1272                 }
1273         }
1274
1275         mutex_unlock(&ebt_mutex);
1276         return NULL;
1277 }
1278
1279 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1280 {
1281         struct ebt_table *table = __ebt_find_table(net, name);
1282
1283         if (table)
1284                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1285 }
1286 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1287
1288 void ebt_unregister_table(struct net *net, const char *name)
1289 {
1290         struct ebt_table *table = __ebt_find_table(net, name);
1291
1292         if (table)
1293                 __ebt_unregister_table(net, table);
1294 }
1295
1296 /* userspace just supplied us with counters */
1297 static int do_update_counters(struct net *net, const char *name,
1298                               struct ebt_counter __user *counters,
1299                               unsigned int num_counters, unsigned int len)
1300 {
1301         int i, ret;
1302         struct ebt_counter *tmp;
1303         struct ebt_table *t;
1304
1305         if (num_counters == 0)
1306                 return -EINVAL;
1307
1308         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1309         if (!tmp)
1310                 return -ENOMEM;
1311
1312         t = find_table_lock(net, name, &ret, &ebt_mutex);
1313         if (!t)
1314                 goto free_tmp;
1315
1316         if (num_counters != t->private->nentries) {
1317                 ret = -EINVAL;
1318                 goto unlock_mutex;
1319         }
1320
1321         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1322                 ret = -EFAULT;
1323                 goto unlock_mutex;
1324         }
1325
1326         /* we want an atomic add of the counters */
1327         write_lock_bh(&t->lock);
1328
1329         /* we add to the counters of the first cpu */
1330         for (i = 0; i < num_counters; i++)
1331                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1332
1333         write_unlock_bh(&t->lock);
1334         ret = 0;
1335 unlock_mutex:
1336         mutex_unlock(&ebt_mutex);
1337 free_tmp:
1338         vfree(tmp);
1339         return ret;
1340 }
1341
1342 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1343 {
1344         struct ebt_replace hlp;
1345
1346         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1347                 return -EFAULT;
1348
1349         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1350                 return -EINVAL;
1351
1352         return do_update_counters(net, hlp.name, hlp.counters,
1353                                   hlp.num_counters, len);
1354 }
1355
1356 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1357                                   const char *data, int entrysize,
1358                                   int usersize, int datasize, u8 revision)
1359 {
1360         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1361
1362         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1363          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1364          */
1365         strlcpy(name, _name, sizeof(name));
1366         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1367             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1368             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1369             xt_data_to_user(um + entrysize, data, usersize, datasize,
1370                             XT_ALIGN(datasize)))
1371                 return -EFAULT;
1372
1373         return 0;
1374 }
1375
1376 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1377                                     const char *base, char __user *ubase)
1378 {
1379         return ebt_obj_to_user(ubase + ((char *)m - base),
1380                                m->u.match->name, m->data, sizeof(*m),
1381                                m->u.match->usersize, m->match_size,
1382                                m->u.match->revision);
1383 }
1384
1385 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1386                                       const char *base, char __user *ubase)
1387 {
1388         return ebt_obj_to_user(ubase + ((char *)w - base),
1389                                w->u.watcher->name, w->data, sizeof(*w),
1390                                w->u.watcher->usersize, w->watcher_size,
1391                                w->u.watcher->revision);
1392 }
1393
1394 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1395                                     char __user *ubase)
1396 {
1397         int ret;
1398         char __user *hlp;
1399         const struct ebt_entry_target *t;
1400
1401         if (e->bitmask == 0) {
1402                 /* special case !EBT_ENTRY_OR_ENTRIES */
1403                 if (copy_to_user(ubase + ((char *)e - base), e,
1404                                  sizeof(struct ebt_entries)))
1405                         return -EFAULT;
1406                 return 0;
1407         }
1408
1409         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1410                 return -EFAULT;
1411
1412         hlp = ubase + (((char *)e + e->target_offset) - base);
1413         t = ebt_get_target_c(e);
1414
1415         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1416         if (ret != 0)
1417                 return ret;
1418         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1419         if (ret != 0)
1420                 return ret;
1421         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1422                               t->u.target->usersize, t->target_size,
1423                               t->u.target->revision);
1424         if (ret != 0)
1425                 return ret;
1426
1427         return 0;
1428 }
1429
1430 static int copy_counters_to_user(struct ebt_table *t,
1431                                  const struct ebt_counter *oldcounters,
1432                                  void __user *user, unsigned int num_counters,
1433                                  unsigned int nentries)
1434 {
1435         struct ebt_counter *counterstmp;
1436         int ret = 0;
1437
1438         /* userspace might not need the counters */
1439         if (num_counters == 0)
1440                 return 0;
1441
1442         if (num_counters != nentries)
1443                 return -EINVAL;
1444
1445         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1446         if (!counterstmp)
1447                 return -ENOMEM;
1448
1449         write_lock_bh(&t->lock);
1450         get_counters(oldcounters, counterstmp, nentries);
1451         write_unlock_bh(&t->lock);
1452
1453         if (copy_to_user(user, counterstmp,
1454            nentries * sizeof(struct ebt_counter)))
1455                 ret = -EFAULT;
1456         vfree(counterstmp);
1457         return ret;
1458 }
1459
1460 /* called with ebt_mutex locked */
1461 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1462                                    const int *len, int cmd)
1463 {
1464         struct ebt_replace tmp;
1465         const struct ebt_counter *oldcounters;
1466         unsigned int entries_size, nentries;
1467         int ret;
1468         char *entries;
1469
1470         if (cmd == EBT_SO_GET_ENTRIES) {
1471                 entries_size = t->private->entries_size;
1472                 nentries = t->private->nentries;
1473                 entries = t->private->entries;
1474                 oldcounters = t->private->counters;
1475         } else {
1476                 entries_size = t->table->entries_size;
1477                 nentries = t->table->nentries;
1478                 entries = t->table->entries;
1479                 oldcounters = t->table->counters;
1480         }
1481
1482         if (copy_from_user(&tmp, user, sizeof(tmp)))
1483                 return -EFAULT;
1484
1485         if (*len != sizeof(struct ebt_replace) + entries_size +
1486            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1487                 return -EINVAL;
1488
1489         if (tmp.nentries != nentries)
1490                 return -EINVAL;
1491
1492         if (tmp.entries_size != entries_size)
1493                 return -EINVAL;
1494
1495         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1496                                         tmp.num_counters, nentries);
1497         if (ret)
1498                 return ret;
1499
1500         /* set the match/watcher/target names right */
1501         return EBT_ENTRY_ITERATE(entries, entries_size,
1502            ebt_entry_to_user, entries, tmp.entries);
1503 }
1504
1505 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1506 /* 32 bit-userspace compatibility definitions. */
1507 struct compat_ebt_replace {
1508         char name[EBT_TABLE_MAXNAMELEN];
1509         compat_uint_t valid_hooks;
1510         compat_uint_t nentries;
1511         compat_uint_t entries_size;
1512         /* start of the chains */
1513         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1514         /* nr of counters userspace expects back */
1515         compat_uint_t num_counters;
1516         /* where the kernel will put the old counters. */
1517         compat_uptr_t counters;
1518         compat_uptr_t entries;
1519 };
1520
1521 /* struct ebt_entry_match, _target and _watcher have same layout */
1522 struct compat_ebt_entry_mwt {
1523         union {
1524                 struct {
1525                         char name[EBT_EXTENSION_MAXNAMELEN];
1526                         u8 revision;
1527                 };
1528                 compat_uptr_t ptr;
1529         } u;
1530         compat_uint_t match_size;
1531         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1532 };
1533
1534 /* account for possible padding between match_size and ->data */
1535 static int ebt_compat_entry_padsize(void)
1536 {
1537         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1538                         sizeof(struct compat_ebt_entry_mwt));
1539         return (int) sizeof(struct ebt_entry_match) -
1540                         sizeof(struct compat_ebt_entry_mwt);
1541 }
1542
1543 static int ebt_compat_match_offset(const struct xt_match *match,
1544                                    unsigned int userlen)
1545 {
1546         /* ebt_among needs special handling. The kernel .matchsize is
1547          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1548          * value is expected.
1549          * Example: userspace sends 4500, ebt_among.c wants 4504.
1550          */
1551         if (unlikely(match->matchsize == -1))
1552                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1553         return xt_compat_match_offset(match);
1554 }
1555
1556 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1557                                 unsigned int *size)
1558 {
1559         const struct xt_match *match = m->u.match;
1560         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1561         int off = ebt_compat_match_offset(match, m->match_size);
1562         compat_uint_t msize = m->match_size - off;
1563
1564         if (WARN_ON(off >= m->match_size))
1565                 return -EINVAL;
1566
1567         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1568             put_user(match->revision, &cm->u.revision) ||
1569             put_user(msize, &cm->match_size))
1570                 return -EFAULT;
1571
1572         if (match->compat_to_user) {
1573                 if (match->compat_to_user(cm->data, m->data))
1574                         return -EFAULT;
1575         } else {
1576                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1577                                     COMPAT_XT_ALIGN(msize)))
1578                         return -EFAULT;
1579         }
1580
1581         *size -= ebt_compat_entry_padsize() + off;
1582         *dstptr = cm->data;
1583         *dstptr += msize;
1584         return 0;
1585 }
1586
1587 static int compat_target_to_user(struct ebt_entry_target *t,
1588                                  void __user **dstptr,
1589                                  unsigned int *size)
1590 {
1591         const struct xt_target *target = t->u.target;
1592         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1593         int off = xt_compat_target_offset(target);
1594         compat_uint_t tsize = t->target_size - off;
1595
1596         if (WARN_ON(off >= t->target_size))
1597                 return -EINVAL;
1598
1599         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1600             put_user(target->revision, &cm->u.revision) ||
1601             put_user(tsize, &cm->match_size))
1602                 return -EFAULT;
1603
1604         if (target->compat_to_user) {
1605                 if (target->compat_to_user(cm->data, t->data))
1606                         return -EFAULT;
1607         } else {
1608                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1609                                     COMPAT_XT_ALIGN(tsize)))
1610                         return -EFAULT;
1611         }
1612
1613         *size -= ebt_compat_entry_padsize() + off;
1614         *dstptr = cm->data;
1615         *dstptr += tsize;
1616         return 0;
1617 }
1618
1619 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1620                                   void __user **dstptr,
1621                                   unsigned int *size)
1622 {
1623         return compat_target_to_user((struct ebt_entry_target *)w,
1624                                                         dstptr, size);
1625 }
1626
1627 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1628                                 unsigned int *size)
1629 {
1630         struct ebt_entry_target *t;
1631         struct ebt_entry __user *ce;
1632         u32 watchers_offset, target_offset, next_offset;
1633         compat_uint_t origsize;
1634         int ret;
1635
1636         if (e->bitmask == 0) {
1637                 if (*size < sizeof(struct ebt_entries))
1638                         return -EINVAL;
1639                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1640                         return -EFAULT;
1641
1642                 *dstptr += sizeof(struct ebt_entries);
1643                 *size -= sizeof(struct ebt_entries);
1644                 return 0;
1645         }
1646
1647         if (*size < sizeof(*ce))
1648                 return -EINVAL;
1649
1650         ce = *dstptr;
1651         if (copy_to_user(ce, e, sizeof(*ce)))
1652                 return -EFAULT;
1653
1654         origsize = *size;
1655         *dstptr += sizeof(*ce);
1656
1657         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1658         if (ret)
1659                 return ret;
1660         watchers_offset = e->watchers_offset - (origsize - *size);
1661
1662         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1663         if (ret)
1664                 return ret;
1665         target_offset = e->target_offset - (origsize - *size);
1666
1667         t = ebt_get_target(e);
1668
1669         ret = compat_target_to_user(t, dstptr, size);
1670         if (ret)
1671                 return ret;
1672         next_offset = e->next_offset - (origsize - *size);
1673
1674         if (put_user(watchers_offset, &ce->watchers_offset) ||
1675             put_user(target_offset, &ce->target_offset) ||
1676             put_user(next_offset, &ce->next_offset))
1677                 return -EFAULT;
1678
1679         *size -= sizeof(*ce);
1680         return 0;
1681 }
1682
1683 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1684 {
1685         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1686         *off += ebt_compat_entry_padsize();
1687         return 0;
1688 }
1689
1690 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1691 {
1692         *off += xt_compat_target_offset(w->u.watcher);
1693         *off += ebt_compat_entry_padsize();
1694         return 0;
1695 }
1696
1697 static int compat_calc_entry(const struct ebt_entry *e,
1698                              const struct ebt_table_info *info,
1699                              const void *base,
1700                              struct compat_ebt_replace *newinfo)
1701 {
1702         const struct ebt_entry_target *t;
1703         unsigned int entry_offset;
1704         int off, ret, i;
1705
1706         if (e->bitmask == 0)
1707                 return 0;
1708
1709         off = 0;
1710         entry_offset = (void *)e - base;
1711
1712         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1713         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1714
1715         t = ebt_get_target_c(e);
1716
1717         off += xt_compat_target_offset(t->u.target);
1718         off += ebt_compat_entry_padsize();
1719
1720         newinfo->entries_size -= off;
1721
1722         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1723         if (ret)
1724                 return ret;
1725
1726         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1727                 const void *hookptr = info->hook_entry[i];
1728                 if (info->hook_entry[i] &&
1729                     (e < (struct ebt_entry *)(base - hookptr))) {
1730                         newinfo->hook_entry[i] -= off;
1731                         pr_debug("0x%08X -> 0x%08X\n",
1732                                         newinfo->hook_entry[i] + off,
1733                                         newinfo->hook_entry[i]);
1734                 }
1735         }
1736
1737         return 0;
1738 }
1739
1740 static int ebt_compat_init_offsets(unsigned int number)
1741 {
1742         if (number > INT_MAX)
1743                 return -EINVAL;
1744
1745         /* also count the base chain policies */
1746         number += NF_BR_NUMHOOKS;
1747
1748         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1749 }
1750
1751 static int compat_table_info(const struct ebt_table_info *info,
1752                              struct compat_ebt_replace *newinfo)
1753 {
1754         unsigned int size = info->entries_size;
1755         const void *entries = info->entries;
1756         int ret;
1757
1758         newinfo->entries_size = size;
1759         ret = ebt_compat_init_offsets(info->nentries);
1760         if (ret)
1761                 return ret;
1762
1763         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1764                                                         entries, newinfo);
1765 }
1766
1767 static int compat_copy_everything_to_user(struct ebt_table *t,
1768                                           void __user *user, int *len, int cmd)
1769 {
1770         struct compat_ebt_replace repl, tmp;
1771         struct ebt_counter *oldcounters;
1772         struct ebt_table_info tinfo;
1773         int ret;
1774         void __user *pos;
1775
1776         memset(&tinfo, 0, sizeof(tinfo));
1777
1778         if (cmd == EBT_SO_GET_ENTRIES) {
1779                 tinfo.entries_size = t->private->entries_size;
1780                 tinfo.nentries = t->private->nentries;
1781                 tinfo.entries = t->private->entries;
1782                 oldcounters = t->private->counters;
1783         } else {
1784                 tinfo.entries_size = t->table->entries_size;
1785                 tinfo.nentries = t->table->nentries;
1786                 tinfo.entries = t->table->entries;
1787                 oldcounters = t->table->counters;
1788         }
1789
1790         if (copy_from_user(&tmp, user, sizeof(tmp)))
1791                 return -EFAULT;
1792
1793         if (tmp.nentries != tinfo.nentries ||
1794            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1795                 return -EINVAL;
1796
1797         memcpy(&repl, &tmp, sizeof(repl));
1798         if (cmd == EBT_SO_GET_ENTRIES)
1799                 ret = compat_table_info(t->private, &repl);
1800         else
1801                 ret = compat_table_info(&tinfo, &repl);
1802         if (ret)
1803                 return ret;
1804
1805         if (*len != sizeof(tmp) + repl.entries_size +
1806            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1807                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1808                                 *len, tinfo.entries_size, repl.entries_size);
1809                 return -EINVAL;
1810         }
1811
1812         /* userspace might not need the counters */
1813         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1814                                         tmp.num_counters, tinfo.nentries);
1815         if (ret)
1816                 return ret;
1817
1818         pos = compat_ptr(tmp.entries);
1819         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1820                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1821 }
1822
1823 struct ebt_entries_buf_state {
1824         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1825         u32 buf_kern_len;       /* total size of kernel buffer */
1826         u32 buf_kern_offset;    /* amount of data copied so far */
1827         u32 buf_user_offset;    /* read position in userspace buffer */
1828 };
1829
1830 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1831 {
1832         state->buf_kern_offset += sz;
1833         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1834 }
1835
1836 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1837                        const void *data, unsigned int sz)
1838 {
1839         if (state->buf_kern_start == NULL)
1840                 goto count_only;
1841
1842         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1843                 return -EINVAL;
1844
1845         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1846
1847  count_only:
1848         state->buf_user_offset += sz;
1849         return ebt_buf_count(state, sz);
1850 }
1851
1852 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1853 {
1854         char *b = state->buf_kern_start;
1855
1856         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1857                 return -EINVAL;
1858
1859         if (b != NULL && sz > 0)
1860                 memset(b + state->buf_kern_offset, 0, sz);
1861         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1862         return ebt_buf_count(state, sz);
1863 }
1864
1865 enum compat_mwt {
1866         EBT_COMPAT_MATCH,
1867         EBT_COMPAT_WATCHER,
1868         EBT_COMPAT_TARGET,
1869 };
1870
1871 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1872                                 enum compat_mwt compat_mwt,
1873                                 struct ebt_entries_buf_state *state,
1874                                 const unsigned char *base)
1875 {
1876         char name[EBT_EXTENSION_MAXNAMELEN];
1877         struct xt_match *match;
1878         struct xt_target *wt;
1879         void *dst = NULL;
1880         int off, pad = 0;
1881         unsigned int size_kern, match_size = mwt->match_size;
1882
1883         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1884                 return -EINVAL;
1885
1886         if (state->buf_kern_start)
1887                 dst = state->buf_kern_start + state->buf_kern_offset;
1888
1889         switch (compat_mwt) {
1890         case EBT_COMPAT_MATCH:
1891                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1892                                               mwt->u.revision);
1893                 if (IS_ERR(match))
1894                         return PTR_ERR(match);
1895
1896                 off = ebt_compat_match_offset(match, match_size);
1897                 if (dst) {
1898                         if (match->compat_from_user)
1899                                 match->compat_from_user(dst, mwt->data);
1900                         else
1901                                 memcpy(dst, mwt->data, match_size);
1902                 }
1903
1904                 size_kern = match->matchsize;
1905                 if (unlikely(size_kern == -1))
1906                         size_kern = match_size;
1907                 module_put(match->me);
1908                 break;
1909         case EBT_COMPAT_WATCHER:
1910         case EBT_COMPAT_TARGET:
1911                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1912                                             mwt->u.revision);
1913                 if (IS_ERR(wt))
1914                         return PTR_ERR(wt);
1915                 off = xt_compat_target_offset(wt);
1916
1917                 if (dst) {
1918                         if (wt->compat_from_user)
1919                                 wt->compat_from_user(dst, mwt->data);
1920                         else
1921                                 memcpy(dst, mwt->data, match_size);
1922                 }
1923
1924                 size_kern = wt->targetsize;
1925                 module_put(wt->me);
1926                 break;
1927
1928         default:
1929                 return -EINVAL;
1930         }
1931
1932         state->buf_kern_offset += match_size + off;
1933         state->buf_user_offset += match_size;
1934         pad = XT_ALIGN(size_kern) - size_kern;
1935
1936         if (pad > 0 && dst) {
1937                 if (WARN_ON(state->buf_kern_len <= pad))
1938                         return -EINVAL;
1939                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
1940                         return -EINVAL;
1941                 memset(dst + size_kern, 0, pad);
1942         }
1943         return off + match_size;
1944 }
1945
1946 /* return size of all matches, watchers or target, including necessary
1947  * alignment and padding.
1948  */
1949 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
1950                         unsigned int size_left, enum compat_mwt type,
1951                         struct ebt_entries_buf_state *state, const void *base)
1952 {
1953         const char *buf = (const char *)match32;
1954         int growth = 0;
1955
1956         if (size_left == 0)
1957                 return 0;
1958
1959         do {
1960                 struct ebt_entry_match *match_kern;
1961                 int ret;
1962
1963                 if (size_left < sizeof(*match32))
1964                         return -EINVAL;
1965
1966                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1967                 if (match_kern) {
1968                         char *tmp;
1969                         tmp = state->buf_kern_start + state->buf_kern_offset;
1970                         match_kern = (struct ebt_entry_match *) tmp;
1971                 }
1972                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1973                 if (ret < 0)
1974                         return ret;
1975                 size_left -= sizeof(*match32);
1976
1977                 /* add padding before match->data (if any) */
1978                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1979                 if (ret < 0)
1980                         return ret;
1981
1982                 if (match32->match_size > size_left)
1983                         return -EINVAL;
1984
1985                 size_left -= match32->match_size;
1986
1987                 ret = compat_mtw_from_user(match32, type, state, base);
1988                 if (ret < 0)
1989                         return ret;
1990
1991                 if (WARN_ON(ret < match32->match_size))
1992                         return -EINVAL;
1993                 growth += ret - match32->match_size;
1994                 growth += ebt_compat_entry_padsize();
1995
1996                 buf += sizeof(*match32);
1997                 buf += match32->match_size;
1998
1999                 if (match_kern)
2000                         match_kern->match_size = ret;
2001
2002                 match32 = (struct compat_ebt_entry_mwt *) buf;
2003         } while (size_left);
2004
2005         return growth;
2006 }
2007
2008 /* called for all ebt_entry structures. */
2009 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2010                           unsigned int *total,
2011                           struct ebt_entries_buf_state *state)
2012 {
2013         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2014         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2015         unsigned int offsets[4];
2016         unsigned int *offsets_update = NULL;
2017         int ret;
2018         char *buf_start;
2019
2020         if (*total < sizeof(struct ebt_entries))
2021                 return -EINVAL;
2022
2023         if (!entry->bitmask) {
2024                 *total -= sizeof(struct ebt_entries);
2025                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2026         }
2027         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2028                 return -EINVAL;
2029
2030         startoff = state->buf_user_offset;
2031         /* pull in most part of ebt_entry, it does not need to be changed. */
2032         ret = ebt_buf_add(state, entry,
2033                         offsetof(struct ebt_entry, watchers_offset));
2034         if (ret < 0)
2035                 return ret;
2036
2037         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2038         memcpy(&offsets[1], &entry->watchers_offset,
2039                         sizeof(offsets) - sizeof(offsets[0]));
2040
2041         if (state->buf_kern_start) {
2042                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2043                 offsets_update = (unsigned int *) buf_start;
2044         }
2045         ret = ebt_buf_add(state, &offsets[1],
2046                         sizeof(offsets) - sizeof(offsets[0]));
2047         if (ret < 0)
2048                 return ret;
2049         buf_start = (char *) entry;
2050         /* 0: matches offset, always follows ebt_entry.
2051          * 1: watchers offset, from ebt_entry structure
2052          * 2: target offset, from ebt_entry structure
2053          * 3: next ebt_entry offset, from ebt_entry structure
2054          *
2055          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2056          */
2057         for (i = 0; i < 4 ; ++i) {
2058                 if (offsets[i] > *total)
2059                         return -EINVAL;
2060
2061                 if (i < 3 && offsets[i] == *total)
2062                         return -EINVAL;
2063
2064                 if (i == 0)
2065                         continue;
2066                 if (offsets[i-1] > offsets[i])
2067                         return -EINVAL;
2068         }
2069
2070         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2071                 struct compat_ebt_entry_mwt *match32;
2072                 unsigned int size;
2073                 char *buf = buf_start + offsets[i];
2074
2075                 if (offsets[i] > offsets[j])
2076                         return -EINVAL;
2077
2078                 match32 = (struct compat_ebt_entry_mwt *) buf;
2079                 size = offsets[j] - offsets[i];
2080                 ret = ebt_size_mwt(match32, size, i, state, base);
2081                 if (ret < 0)
2082                         return ret;
2083                 new_offset += ret;
2084                 if (offsets_update && new_offset) {
2085                         pr_debug("change offset %d to %d\n",
2086                                 offsets_update[i], offsets[j] + new_offset);
2087                         offsets_update[i] = offsets[j] + new_offset;
2088                 }
2089         }
2090
2091         if (state->buf_kern_start == NULL) {
2092                 unsigned int offset = buf_start - (char *) base;
2093
2094                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2095                 if (ret < 0)
2096                         return ret;
2097         }
2098
2099         next_expected_off = state->buf_user_offset - startoff;
2100         if (next_expected_off != entry->next_offset)
2101                 return -EINVAL;
2102
2103         if (*total < entry->next_offset)
2104                 return -EINVAL;
2105         *total -= entry->next_offset;
2106         return 0;
2107 }
2108
2109 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2110  * It might need more memory when copied to a 64 bit kernel in case
2111  * userspace is 32-bit. So, first task: find out how much memory is needed.
2112  *
2113  * Called before validation is performed.
2114  */
2115 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2116                                 struct ebt_entries_buf_state *state)
2117 {
2118         unsigned int size_remaining = size_user;
2119         int ret;
2120
2121         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2122                                         &size_remaining, state);
2123         if (ret < 0)
2124                 return ret;
2125
2126         if (size_remaining)
2127                 return -EINVAL;
2128
2129         return state->buf_kern_offset;
2130 }
2131
2132
2133 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2134                                              sockptr_t arg, unsigned int len)
2135 {
2136         struct compat_ebt_replace tmp;
2137         int i;
2138
2139         if (len < sizeof(tmp))
2140                 return -EINVAL;
2141
2142         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2143                 return -EFAULT;
2144
2145         if (len != sizeof(tmp) + tmp.entries_size)
2146                 return -EINVAL;
2147
2148         if (tmp.entries_size == 0)
2149                 return -EINVAL;
2150
2151         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2152                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2153                 return -ENOMEM;
2154         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2155                 return -ENOMEM;
2156
2157         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2158
2159         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2160         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2161                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2162
2163         repl->num_counters = tmp.num_counters;
2164         repl->counters = compat_ptr(tmp.counters);
2165         repl->entries = compat_ptr(tmp.entries);
2166         return 0;
2167 }
2168
2169 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2170 {
2171         int ret, i, countersize, size64;
2172         struct ebt_table_info *newinfo;
2173         struct ebt_replace tmp;
2174         struct ebt_entries_buf_state state;
2175         void *entries_tmp;
2176
2177         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2178         if (ret) {
2179                 /* try real handler in case userland supplied needed padding */
2180                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2181                         ret = 0;
2182                 return ret;
2183         }
2184
2185         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2186         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2187         if (!newinfo)
2188                 return -ENOMEM;
2189
2190         if (countersize)
2191                 memset(newinfo->counters, 0, countersize);
2192
2193         memset(&state, 0, sizeof(state));
2194
2195         newinfo->entries = vmalloc(tmp.entries_size);
2196         if (!newinfo->entries) {
2197                 ret = -ENOMEM;
2198                 goto free_newinfo;
2199         }
2200         if (copy_from_user(
2201            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2202                 ret = -EFAULT;
2203                 goto free_entries;
2204         }
2205
2206         entries_tmp = newinfo->entries;
2207
2208         xt_compat_lock(NFPROTO_BRIDGE);
2209
2210         ret = ebt_compat_init_offsets(tmp.nentries);
2211         if (ret < 0)
2212                 goto out_unlock;
2213
2214         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2215         if (ret < 0)
2216                 goto out_unlock;
2217
2218         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2219                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2220                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2221
2222         size64 = ret;
2223         newinfo->entries = vmalloc(size64);
2224         if (!newinfo->entries) {
2225                 vfree(entries_tmp);
2226                 ret = -ENOMEM;
2227                 goto out_unlock;
2228         }
2229
2230         memset(&state, 0, sizeof(state));
2231         state.buf_kern_start = newinfo->entries;
2232         state.buf_kern_len = size64;
2233
2234         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2235         if (WARN_ON(ret < 0)) {
2236                 vfree(entries_tmp);
2237                 goto out_unlock;
2238         }
2239
2240         vfree(entries_tmp);
2241         tmp.entries_size = size64;
2242
2243         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2244                 char __user *usrptr;
2245                 if (tmp.hook_entry[i]) {
2246                         unsigned int delta;
2247                         usrptr = (char __user *) tmp.hook_entry[i];
2248                         delta = usrptr - tmp.entries;
2249                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2250                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2251                 }
2252         }
2253
2254         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2255         xt_compat_unlock(NFPROTO_BRIDGE);
2256
2257         ret = do_replace_finish(net, &tmp, newinfo);
2258         if (ret == 0)
2259                 return ret;
2260 free_entries:
2261         vfree(newinfo->entries);
2262 free_newinfo:
2263         vfree(newinfo);
2264         return ret;
2265 out_unlock:
2266         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2267         xt_compat_unlock(NFPROTO_BRIDGE);
2268         goto free_entries;
2269 }
2270
2271 static int compat_update_counters(struct net *net, sockptr_t arg,
2272                                   unsigned int len)
2273 {
2274         struct compat_ebt_replace hlp;
2275
2276         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2277                 return -EFAULT;
2278
2279         /* try real handler in case userland supplied needed padding */
2280         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2281                 return update_counters(net, arg, len);
2282
2283         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2284                                   hlp.num_counters, len);
2285 }
2286
2287 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2288                 void __user *user, int *len)
2289 {
2290         int ret;
2291         struct compat_ebt_replace tmp;
2292         struct ebt_table *t;
2293         struct net *net = sock_net(sk);
2294
2295         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2296             *len != sizeof(struct compat_ebt_replace))
2297                 return -EINVAL;
2298
2299         if (copy_from_user(&tmp, user, sizeof(tmp)))
2300                 return -EFAULT;
2301
2302         tmp.name[sizeof(tmp.name) - 1] = '\0';
2303
2304         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2305         if (!t)
2306                 return ret;
2307
2308         xt_compat_lock(NFPROTO_BRIDGE);
2309         switch (cmd) {
2310         case EBT_SO_GET_INFO:
2311                 tmp.nentries = t->private->nentries;
2312                 ret = compat_table_info(t->private, &tmp);
2313                 if (ret)
2314                         goto out;
2315                 tmp.valid_hooks = t->valid_hooks;
2316
2317                 if (copy_to_user(user, &tmp, *len) != 0) {
2318                         ret = -EFAULT;
2319                         break;
2320                 }
2321                 ret = 0;
2322                 break;
2323         case EBT_SO_GET_INIT_INFO:
2324                 tmp.nentries = t->table->nentries;
2325                 tmp.entries_size = t->table->entries_size;
2326                 tmp.valid_hooks = t->table->valid_hooks;
2327
2328                 if (copy_to_user(user, &tmp, *len) != 0) {
2329                         ret = -EFAULT;
2330                         break;
2331                 }
2332                 ret = 0;
2333                 break;
2334         case EBT_SO_GET_ENTRIES:
2335         case EBT_SO_GET_INIT_ENTRIES:
2336                 /* try real handler first in case of userland-side padding.
2337                  * in case we are dealing with an 'ordinary' 32 bit binary
2338                  * without 64bit compatibility padding, this will fail right
2339                  * after copy_from_user when the *len argument is validated.
2340                  *
2341                  * the compat_ variant needs to do one pass over the kernel
2342                  * data set to adjust for size differences before it the check.
2343                  */
2344                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2345                         ret = 0;
2346                 else
2347                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2348                 break;
2349         default:
2350                 ret = -EINVAL;
2351         }
2352  out:
2353         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2354         xt_compat_unlock(NFPROTO_BRIDGE);
2355         mutex_unlock(&ebt_mutex);
2356         return ret;
2357 }
2358 #endif
2359
2360 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2361 {
2362         struct net *net = sock_net(sk);
2363         struct ebt_replace tmp;
2364         struct ebt_table *t;
2365         int ret;
2366
2367         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2368                 return -EPERM;
2369
2370 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2371         /* try real handler in case userland supplied needed padding */
2372         if (in_compat_syscall() &&
2373             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2374              *len != sizeof(tmp)))
2375                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2376 #endif
2377
2378         if (copy_from_user(&tmp, user, sizeof(tmp)))
2379                 return -EFAULT;
2380
2381         tmp.name[sizeof(tmp.name) - 1] = '\0';
2382
2383         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2384         if (!t)
2385                 return ret;
2386
2387         switch (cmd) {
2388         case EBT_SO_GET_INFO:
2389         case EBT_SO_GET_INIT_INFO:
2390                 if (*len != sizeof(struct ebt_replace)) {
2391                         ret = -EINVAL;
2392                         mutex_unlock(&ebt_mutex);
2393                         break;
2394                 }
2395                 if (cmd == EBT_SO_GET_INFO) {
2396                         tmp.nentries = t->private->nentries;
2397                         tmp.entries_size = t->private->entries_size;
2398                         tmp.valid_hooks = t->valid_hooks;
2399                 } else {
2400                         tmp.nentries = t->table->nentries;
2401                         tmp.entries_size = t->table->entries_size;
2402                         tmp.valid_hooks = t->table->valid_hooks;
2403                 }
2404                 mutex_unlock(&ebt_mutex);
2405                 if (copy_to_user(user, &tmp, *len) != 0) {
2406                         ret = -EFAULT;
2407                         break;
2408                 }
2409                 ret = 0;
2410                 break;
2411
2412         case EBT_SO_GET_ENTRIES:
2413         case EBT_SO_GET_INIT_ENTRIES:
2414                 ret = copy_everything_to_user(t, user, len, cmd);
2415                 mutex_unlock(&ebt_mutex);
2416                 break;
2417
2418         default:
2419                 mutex_unlock(&ebt_mutex);
2420                 ret = -EINVAL;
2421         }
2422
2423         return ret;
2424 }
2425
2426 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2427                 unsigned int len)
2428 {
2429         struct net *net = sock_net(sk);
2430         int ret;
2431
2432         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2433                 return -EPERM;
2434
2435         switch (cmd) {
2436         case EBT_SO_SET_ENTRIES:
2437 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2438                 if (in_compat_syscall())
2439                         ret = compat_do_replace(net, arg, len);
2440                 else
2441 #endif
2442                         ret = do_replace(net, arg, len);
2443                 break;
2444         case EBT_SO_SET_COUNTERS:
2445 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2446                 if (in_compat_syscall())
2447                         ret = compat_update_counters(net, arg, len);
2448                 else
2449 #endif
2450                         ret = update_counters(net, arg, len);
2451                 break;
2452         default:
2453                 ret = -EINVAL;
2454         }
2455         return ret;
2456 }
2457
2458 static struct nf_sockopt_ops ebt_sockopts = {
2459         .pf             = PF_INET,
2460         .set_optmin     = EBT_BASE_CTL,
2461         .set_optmax     = EBT_SO_SET_MAX + 1,
2462         .set            = do_ebt_set_ctl,
2463         .get_optmin     = EBT_BASE_CTL,
2464         .get_optmax     = EBT_SO_GET_MAX + 1,
2465         .get            = do_ebt_get_ctl,
2466         .owner          = THIS_MODULE,
2467 };
2468
2469 static int __net_init ebt_pernet_init(struct net *net)
2470 {
2471         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2472
2473         INIT_LIST_HEAD(&ebt_net->tables);
2474         return 0;
2475 }
2476
2477 static struct pernet_operations ebt_net_ops = {
2478         .init = ebt_pernet_init,
2479         .id   = &ebt_pernet_id,
2480         .size = sizeof(struct ebt_pernet),
2481 };
2482
2483 static int __init ebtables_init(void)
2484 {
2485         int ret;
2486
2487         ret = xt_register_target(&ebt_standard_target);
2488         if (ret < 0)
2489                 return ret;
2490         ret = nf_register_sockopt(&ebt_sockopts);
2491         if (ret < 0) {
2492                 xt_unregister_target(&ebt_standard_target);
2493                 return ret;
2494         }
2495
2496         ret = register_pernet_subsys(&ebt_net_ops);
2497         if (ret < 0) {
2498                 nf_unregister_sockopt(&ebt_sockopts);
2499                 xt_unregister_target(&ebt_standard_target);
2500                 return ret;
2501         }
2502
2503         return 0;
2504 }
2505
2506 static void ebtables_fini(void)
2507 {
2508         nf_unregister_sockopt(&ebt_sockopts);
2509         xt_unregister_target(&ebt_standard_target);
2510         unregister_pernet_subsys(&ebt_net_ops);
2511 }
2512
2513 EXPORT_SYMBOL(ebt_register_table);
2514 EXPORT_SYMBOL(ebt_unregister_table);
2515 EXPORT_SYMBOL(ebt_do_table);
2516 module_init(ebtables_init);
2517 module_exit(ebtables_fini);
2518 MODULE_LICENSE("GPL");