net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is strongly inspired by the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  37
  38 /* Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48                                  COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_action_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 /* Do some firewalling */
 181 unsigned int ebt_do_table(struct sk_buff *skb,
 182                           const struct nf_hook_state *state,
 183                           struct ebt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         int i, nentries;
 187         struct ebt_entry *point;
 188         struct ebt_counter *counter_base, *cb_base;
 189         const struct ebt_entry_target *t;
 190         int verdict, sp = 0;
 191         struct ebt_chainstack *cs;
 192         struct ebt_entries *chaininfo;
 193         const char *base;
 194         const struct ebt_table_info *private;
 195         struct xt_action_param acpar;
 196
 197         acpar.state   = state;
 198         acpar.hotdrop = false;
 199
 200         read_lock_bh(&table->lock);
 201         private = table->private;
 202         cb_base = COUNTER_BASE(private->counters, private->nentries,
 203            smp_processor_id());
 204         if (private->chainstack)
 205                 cs = private->chainstack[smp_processor_id()];
 206         else
 207                 cs = NULL;
 208         chaininfo = private->hook_entry[hook];
 209         nentries = private->hook_entry[hook]->nentries;
 210         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 211         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 212         /* base for chain jumps */
 213         base = private->entries;
 214         i = 0;
 215         while (i < nentries) {
 216                 if (ebt_basic_match(point, skb, state->in, state->out))
 217                         goto letscontinue;
 218
 219                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 220                         goto letscontinue;
 221                 if (acpar.hotdrop) {
 222                         read_unlock_bh(&table->lock);
 223                         return NF_DROP;
 224                 }
 225
 226                 /* increase counter */
 227                 (*(counter_base + i)).pcnt++;
 228                 (*(counter_base + i)).bcnt += skb->len;
 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 = (struct ebt_entry_target *)
 236                    (((char *)point) + point->target_offset);
 237                 /* standard target */
 238                 if (!t->u.target->target)
 239                         verdict = ((struct ebt_standard_target *)t)->verdict;
 240                 else {
 241                         acpar.target   = t->u.target;
 242                         acpar.targinfo = t->data;
 243                         verdict = t->u.target->target(skb, &acpar);
 244                 }
 245                 if (verdict == EBT_ACCEPT) {
 246                         read_unlock_bh(&table->lock);
 247                         return NF_ACCEPT;
 248                 }
 249                 if (verdict == EBT_DROP) {
 250                         read_unlock_bh(&table->lock);
 251                         return NF_DROP;
 252                 }
 253                 if (verdict == EBT_RETURN) {
 254 letsreturn:
 255 #ifdef CONFIG_NETFILTER_DEBUG
 256                         if (sp == 0) {
 257                                 BUGPRINT("RETURN on base chain");
 258                                 /* act like this is EBT_CONTINUE */
 259                                 goto letscontinue;
 260                         }
 261 #endif
 262                         sp--;
 263                         /* put all the local variables right */
 264                         i = cs[sp].n;
 265                         chaininfo = cs[sp].chaininfo;
 266                         nentries = chaininfo->nentries;
 267                         point = cs[sp].e;
 268                         counter_base = cb_base +
 269                            chaininfo->counter_offset;
 270                         continue;
 271                 }
 272                 if (verdict == EBT_CONTINUE)
 273                         goto letscontinue;
 274 #ifdef CONFIG_NETFILTER_DEBUG
 275                 if (verdict < 0) {
 276                         BUGPRINT("bogus standard verdict\n");
 277                         read_unlock_bh(&table->lock);
 278                         return NF_DROP;
 279                 }
 280 #endif
 281                 /* jump to a udc */
 282                 cs[sp].n = i + 1;
 283                 cs[sp].chaininfo = chaininfo;
 284                 cs[sp].e = ebt_next_entry(point);
 285                 i = 0;
 286                 chaininfo = (struct ebt_entries *) (base + verdict);
 287 #ifdef CONFIG_NETFILTER_DEBUG
 288                 if (chaininfo->distinguisher) {
 289                         BUGPRINT("jump to non-chain\n");
 290                         read_unlock_bh(&table->lock);
 291                         return NF_DROP;
 292                 }
 293 #endif
 294                 nentries = chaininfo->nentries;
 295                 point = (struct ebt_entry *)chaininfo->data;
 296                 counter_base = cb_base + chaininfo->counter_offset;
 297                 sp++;
 298                 continue;
 299 letscontinue:
 300                 point = ebt_next_entry(point);
 301                 i++;
 302         }
 303
 304         /* I actually like this :) */
 305         if (chaininfo->policy == EBT_RETURN)
 306                 goto letsreturn;
 307         if (chaininfo->policy == EBT_ACCEPT) {
 308                 read_unlock_bh(&table->lock);
 309                 return NF_ACCEPT;
 310         }
 311         read_unlock_bh(&table->lock);
 312         return NF_DROP;
 313 }
 314
 315 /* If it succeeds, returns element and locks mutex */
 316 static inline void *
 317 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 318                         struct mutex *mutex)
 319 {
 320         struct {
 321                 struct list_head list;
 322                 char name[EBT_FUNCTION_MAXNAMELEN];
 323         } *e;
 324
 325         mutex_lock(mutex);
 326         list_for_each_entry(e, head, list) {
 327                 if (strcmp(e->name, name) == 0)
 328                         return e;
 329         }
 330         *error = -ENOENT;
 331         mutex_unlock(mutex);
 332         return NULL;
 333 }
 334
 335 static void *
 336 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 337                  int *error, struct mutex *mutex)
 338 {
 339         return try_then_request_module(
 340                         find_inlist_lock_noload(head, name, error, mutex),
 341                         "%s%s", prefix, name);
 342 }
 343
 344 static inline struct ebt_table *
 345 find_table_lock(struct net *net, const char *name, int *error,
 346                 struct mutex *mutex)
 347 {
 348         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 349                                 "ebtable_", error, mutex);
 350 }
 351
 352 static inline int
 353 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 354                 unsigned int *cnt)
 355 {
 356         const struct ebt_entry *e = par->entryinfo;
 357         struct xt_match *match;
 358         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 359         int ret;
 360
 361         if (left < sizeof(struct ebt_entry_match) ||
 362             left - sizeof(struct ebt_entry_match) < m->match_size)
 363                 return -EINVAL;
 364
 365         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 366         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 367                 if (!IS_ERR(match))
 368                         module_put(match->me);
 369                 request_module("ebt_%s", m->u.name);
 370                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 371         }
 372         if (IS_ERR(match))
 373                 return PTR_ERR(match);
 374         m->u.match = match;
 375
 376         par->match     = match;
 377         par->matchinfo = m->data;
 378         ret = xt_check_match(par, m->match_size,
 379               e->ethproto, e->invflags & EBT_IPROTO);
 380         if (ret < 0) {
 381                 module_put(match->me);
 382                 return ret;
 383         }
 384
 385         (*cnt)++;
 386         return 0;
 387 }
 388
 389 static inline int
 390 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 391                   unsigned int *cnt)
 392 {
 393         const struct ebt_entry *e = par->entryinfo;
 394         struct xt_target *watcher;
 395         size_t left = ((char *)e + e->target_offset) - (char *)w;
 396         int ret;
 397
 398         if (left < sizeof(struct ebt_entry_watcher) ||
 399            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 400                 return -EINVAL;
 401
 402         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 403         if (IS_ERR(watcher))
 404                 return PTR_ERR(watcher);
 405         w->u.watcher = watcher;
 406
 407         par->target   = watcher;
 408         par->targinfo = w->data;
 409         ret = xt_check_target(par, w->watcher_size,
 410               e->ethproto, e->invflags & EBT_IPROTO);
 411         if (ret < 0) {
 412                 module_put(watcher->me);
 413                 return ret;
 414         }
 415
 416         (*cnt)++;
 417         return 0;
 418 }
 419
 420 static int ebt_verify_pointers(const struct ebt_replace *repl,
 421                                struct ebt_table_info *newinfo)
 422 {
 423         unsigned int limit = repl->entries_size;
 424         unsigned int valid_hooks = repl->valid_hooks;
 425         unsigned int offset = 0;
 426         int i;
 427
 428         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 429                 newinfo->hook_entry[i] = NULL;
 430
 431         newinfo->entries_size = repl->entries_size;
 432         newinfo->nentries = repl->nentries;
 433
 434         while (offset < limit) {
 435                 size_t left = limit - offset;
 436                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 437
 438                 if (left < sizeof(unsigned int))
 439                         break;
 440
 441                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 442                         if ((valid_hooks & (1 << i)) == 0)
 443                                 continue;
 444                         if ((char __user *)repl->hook_entry[i] ==
 445                              repl->entries + offset)
 446                                 break;
 447                 }
 448
 449                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 450                         if (e->bitmask != 0) {
 451                                 /* we make userspace set this right,
 452                                  * so there is no misunderstanding
 453                                  */
 454                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 455                                          "in distinguisher\n");
 456                                 return -EINVAL;
 457                         }
 458                         if (i != NF_BR_NUMHOOKS)
 459                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 460                         if (left < sizeof(struct ebt_entries))
 461                                 break;
 462                         offset += sizeof(struct ebt_entries);
 463                 } else {
 464                         if (left < sizeof(struct ebt_entry))
 465                                 break;
 466                         if (left < e->next_offset)
 467                                 break;
 468                         if (e->next_offset < sizeof(struct ebt_entry))
 469                                 return -EINVAL;
 470                         offset += e->next_offset;
 471                 }
 472         }
 473         if (offset != limit) {
 474                 BUGPRINT("entries_size too small\n");
 475                 return -EINVAL;
 476         }
 477
 478         /* check if all valid hooks have a chain */
 479         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 480                 if (!newinfo->hook_entry[i] &&
 481                    (valid_hooks & (1 << i))) {
 482                         BUGPRINT("Valid hook without chain\n");
 483                         return -EINVAL;
 484                 }
 485         }
 486         return 0;
 487 }
 488
 489 /* this one is very careful, as it is the first function
 490  * to parse the userspace data
 491  */
 492 static inline int
 493 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 494                                const struct ebt_table_info *newinfo,
 495                                unsigned int *n, unsigned int *cnt,
 496                                unsigned int *totalcnt, unsigned int *udc_cnt)
 497 {
 498         int i;
 499
 500         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 501                 if ((void *)e == (void *)newinfo->hook_entry[i])
 502                         break;
 503         }
 504         /* beginning of a new chain
 505          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 506          */
 507         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 508                 /* this checks if the previous chain has as many entries
 509                  * as it said it has
 510                  */
 511                 if (*n != *cnt) {
 512                         BUGPRINT("nentries does not equal the nr of entries "
 513                                  "in the chain\n");
 514                         return -EINVAL;
 515                 }
 516                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 517                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 518                         /* only RETURN from udc */
 519                         if (i != NF_BR_NUMHOOKS ||
 520                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 521                                 BUGPRINT("bad policy\n");
 522                                 return -EINVAL;
 523                         }
 524                 }
 525                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 526                         (*udc_cnt)++;
 527                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 528                         BUGPRINT("counter_offset != totalcnt");
 529                         return -EINVAL;
 530                 }
 531                 *n = ((struct ebt_entries *)e)->nentries;
 532                 *cnt = 0;
 533                 return 0;
 534         }
 535         /* a plain old entry, heh */
 536         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 537            e->watchers_offset > e->target_offset ||
 538            e->target_offset >= e->next_offset) {
 539                 BUGPRINT("entry offsets not in right order\n");
 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                 BUGPRINT("target size too small\n");
 545                 return -EINVAL;
 546         }
 547         (*cnt)++;
 548         (*totalcnt)++;
 549         return 0;
 550 }
 551
 552 struct ebt_cl_stack {
 553         struct ebt_chainstack cs;
 554         int from;
 555         unsigned int hookmask;
 556 };
 557
 558 /* We need these positions to check that the jumps to a different part of the
 559  * entries is a jump to the beginning of a new chain.
 560  */
 561 static inline int
 562 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 563                       unsigned int *n, struct ebt_cl_stack *udc)
 564 {
 565         int i;
 566
 567         /* we're only interested in chain starts */
 568         if (e->bitmask)
 569                 return 0;
 570         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 571                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 572                         break;
 573         }
 574         /* only care about udc */
 575         if (i != NF_BR_NUMHOOKS)
 576                 return 0;
 577
 578         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 579         /* these initialisations are depended on later in check_chainloops() */
 580         udc[*n].cs.n = 0;
 581         udc[*n].hookmask = 0;
 582
 583         (*n)++;
 584         return 0;
 585 }
 586
 587 static inline int
 588 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 589 {
 590         struct xt_mtdtor_param par;
 591
 592         if (i && (*i)-- == 0)
 593                 return 1;
 594
 595         par.net       = net;
 596         par.match     = m->u.match;
 597         par.matchinfo = m->data;
 598         par.family    = NFPROTO_BRIDGE;
 599         if (par.match->destroy != NULL)
 600                 par.match->destroy(&par);
 601         module_put(par.match->me);
 602         return 0;
 603 }
 604
 605 static inline int
 606 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 607 {
 608         struct xt_tgdtor_param par;
 609
 610         if (i && (*i)-- == 0)
 611                 return 1;
 612
 613         par.net      = net;
 614         par.target   = w->u.watcher;
 615         par.targinfo = w->data;
 616         par.family   = NFPROTO_BRIDGE;
 617         if (par.target->destroy != NULL)
 618                 par.target->destroy(&par);
 619         module_put(par.target->me);
 620         return 0;
 621 }
 622
 623 static inline int
 624 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 625 {
 626         struct xt_tgdtor_param par;
 627         struct ebt_entry_target *t;
 628
 629         if (e->bitmask == 0)
 630                 return 0;
 631         /* we're done */
 632         if (cnt && (*cnt)-- == 0)
 633                 return 1;
 634         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 635         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 636         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 637
 638         par.net      = net;
 639         par.target   = t->u.target;
 640         par.targinfo = t->data;
 641         par.family   = NFPROTO_BRIDGE;
 642         if (par.target->destroy != NULL)
 643                 par.target->destroy(&par);
 644         module_put(par.target->me);
 645         return 0;
 646 }
 647
 648 static inline int
 649 ebt_check_entry(struct ebt_entry *e, struct net *net,
 650                 const struct ebt_table_info *newinfo,
 651                 const char *name, unsigned int *cnt,
 652                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 653 {
 654         struct ebt_entry_target *t;
 655         struct xt_target *target;
 656         unsigned int i, j, hook = 0, hookmask = 0;
 657         size_t gap;
 658         int ret;
 659         struct xt_mtchk_param mtpar;
 660         struct xt_tgchk_param tgpar;
 661
 662         /* don't mess with the struct ebt_entries */
 663         if (e->bitmask == 0)
 664                 return 0;
 665
 666         if (e->bitmask & ~EBT_F_MASK) {
 667                 BUGPRINT("Unknown flag for bitmask\n");
 668                 return -EINVAL;
 669         }
 670         if (e->invflags & ~EBT_INV_MASK) {
 671                 BUGPRINT("Unknown flag for inv bitmask\n");
 672                 return -EINVAL;
 673         }
 674         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 675                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 676                 return -EINVAL;
 677         }
 678         /* what hook do we belong to? */
 679         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 680                 if (!newinfo->hook_entry[i])
 681                         continue;
 682                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 683                         hook = i;
 684                 else
 685                         break;
 686         }
 687         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 688          * a base chain
 689          */
 690         if (i < NF_BR_NUMHOOKS)
 691                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 692         else {
 693                 for (i = 0; i < udc_cnt; i++)
 694                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 695                                 break;
 696                 if (i == 0)
 697                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 698                 else
 699                         hookmask = cl_s[i - 1].hookmask;
 700         }
 701         i = 0;
 702
 703         mtpar.net       = tgpar.net       = net;
 704         mtpar.table     = tgpar.table     = name;
 705         mtpar.entryinfo = tgpar.entryinfo = e;
 706         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 707         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 708         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 709         if (ret != 0)
 710                 goto cleanup_matches;
 711         j = 0;
 712         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 713         if (ret != 0)
 714                 goto cleanup_watchers;
 715         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 716         gap = e->next_offset - e->target_offset;
 717
 718         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 719         if (IS_ERR(target)) {
 720                 ret = PTR_ERR(target);
 721                 goto cleanup_watchers;
 722         }
 723
 724         t->u.target = target;
 725         if (t->u.target == &ebt_standard_target) {
 726                 if (gap < sizeof(struct ebt_standard_target)) {
 727                         BUGPRINT("Standard target size too big\n");
 728                         ret = -EFAULT;
 729                         goto cleanup_watchers;
 730                 }
 731                 if (((struct ebt_standard_target *)t)->verdict <
 732                    -NUM_STANDARD_TARGETS) {
 733                         BUGPRINT("Invalid standard target\n");
 734                         ret = -EFAULT;
 735                         goto cleanup_watchers;
 736                 }
 737         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 738                 module_put(t->u.target->me);
 739                 ret = -EFAULT;
 740                 goto cleanup_watchers;
 741         }
 742
 743         tgpar.target   = target;
 744         tgpar.targinfo = t->data;
 745         ret = xt_check_target(&tgpar, t->target_size,
 746               e->ethproto, e->invflags & EBT_IPROTO);
 747         if (ret < 0) {
 748                 module_put(target->me);
 749                 goto cleanup_watchers;
 750         }
 751         (*cnt)++;
 752         return 0;
 753 cleanup_watchers:
 754         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 755 cleanup_matches:
 756         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 757         return ret;
 758 }
 759
 760 /* checks for loops and sets the hook mask for udc
 761  * the hook mask for udc tells us from which base chains the udc can be
 762  * accessed. This mask is a parameter to the check() functions of the extensions
 763  */
 764 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 765                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 766 {
 767         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 768         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 769         const struct ebt_entry_target *t;
 770
 771         while (pos < nentries || chain_nr != -1) {
 772                 /* end of udc, go back one 'recursion' step */
 773                 if (pos == nentries) {
 774                         /* put back values of the time when this chain was called */
 775                         e = cl_s[chain_nr].cs.e;
 776                         if (cl_s[chain_nr].from != -1)
 777                                 nentries =
 778                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 779                         else
 780                                 nentries = chain->nentries;
 781                         pos = cl_s[chain_nr].cs.n;
 782                         /* make sure we won't see a loop that isn't one */
 783                         cl_s[chain_nr].cs.n = 0;
 784                         chain_nr = cl_s[chain_nr].from;
 785                         if (pos == nentries)
 786                                 continue;
 787                 }
 788                 t = (struct ebt_entry_target *)
 789                    (((char *)e) + e->target_offset);
 790                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 791                         goto letscontinue;
 792                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 793                    e->next_offset) {
 794                         BUGPRINT("Standard target size too big\n");
 795                         return -1;
 796                 }
 797                 verdict = ((struct ebt_standard_target *)t)->verdict;
 798                 if (verdict >= 0) { /* jump to another chain */
 799                         struct ebt_entries *hlp2 =
 800                            (struct ebt_entries *)(base + verdict);
 801                         for (i = 0; i < udc_cnt; i++)
 802                                 if (hlp2 == cl_s[i].cs.chaininfo)
 803                                         break;
 804                         /* bad destination or loop */
 805                         if (i == udc_cnt) {
 806                                 BUGPRINT("bad destination\n");
 807                                 return -1;
 808                         }
 809                         if (cl_s[i].cs.n) {
 810                                 BUGPRINT("loop\n");
 811                                 return -1;
 812                         }
 813                         if (cl_s[i].hookmask & (1 << hooknr))
 814                                 goto letscontinue;
 815                         /* this can't be 0, so the loop test is correct */
 816                         cl_s[i].cs.n = pos + 1;
 817                         pos = 0;
 818                         cl_s[i].cs.e = ebt_next_entry(e);
 819                         e = (struct ebt_entry *)(hlp2->data);
 820                         nentries = hlp2->nentries;
 821                         cl_s[i].from = chain_nr;
 822                         chain_nr = i;
 823                         /* this udc is accessible from the base chain for hooknr */
 824                         cl_s[i].hookmask |= (1 << hooknr);
 825                         continue;
 826                 }
 827 letscontinue:
 828                 e = ebt_next_entry(e);
 829                 pos++;
 830         }
 831         return 0;
 832 }
 833
 834 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 835 static int translate_table(struct net *net, const char *name,
 836                            struct ebt_table_info *newinfo)
 837 {
 838         unsigned int i, j, k, udc_cnt;
 839         int ret;
 840         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 841
 842         i = 0;
 843         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 844                 i++;
 845         if (i == NF_BR_NUMHOOKS) {
 846                 BUGPRINT("No valid hooks specified\n");
 847                 return -EINVAL;
 848         }
 849         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 850                 BUGPRINT("Chains don't start at beginning\n");
 851                 return -EINVAL;
 852         }
 853         /* make sure chains are ordered after each other in same order
 854          * as their corresponding hooks
 855          */
 856         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 857                 if (!newinfo->hook_entry[j])
 858                         continue;
 859                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 860                         BUGPRINT("Hook order must be followed\n");
 861                         return -EINVAL;
 862                 }
 863                 i = j;
 864         }
 865
 866         /* do some early checkings and initialize some things */
 867         i = 0; /* holds the expected nr. of entries for the chain */
 868         j = 0; /* holds the up to now counted entries for the chain */
 869         k = 0; /* holds the total nr. of entries, should equal
 870                 * newinfo->nentries afterwards
 871                 */
 872         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 873         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 874            ebt_check_entry_size_and_hooks, newinfo,
 875            &i, &j, &k, &udc_cnt);
 876
 877         if (ret != 0)
 878                 return ret;
 879
 880         if (i != j) {
 881                 BUGPRINT("nentries does not equal the nr of entries in the "
 882                          "(last) chain\n");
 883                 return -EINVAL;
 884         }
 885         if (k != newinfo->nentries) {
 886                 BUGPRINT("Total nentries is wrong\n");
 887                 return -EINVAL;
 888         }
 889
 890         /* get the location of the udc, put them in an array
 891          * while we're at it, allocate the chainstack
 892          */
 893         if (udc_cnt) {
 894                 /* this will get free'd in do_replace()/ebt_register_table()
 895                  * if an error occurs
 896                  */
 897                 newinfo->chainstack =
 898                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 899                 if (!newinfo->chainstack)
 900                         return -ENOMEM;
 901                 for_each_possible_cpu(i) {
 902                         newinfo->chainstack[i] =
 903                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 904                         if (!newinfo->chainstack[i]) {
 905                                 while (i)
 906                                         vfree(newinfo->chainstack[--i]);
 907                                 vfree(newinfo->chainstack);
 908                                 newinfo->chainstack = NULL;
 909                                 return -ENOMEM;
 910                         }
 911                 }
 912
 913                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 914                 if (!cl_s)
 915                         return -ENOMEM;
 916                 i = 0; /* the i'th udc */
 917                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 918                    ebt_get_udc_positions, newinfo, &i, cl_s);
 919                 /* sanity check */
 920                 if (i != udc_cnt) {
 921                         BUGPRINT("i != udc_cnt\n");
 922                         vfree(cl_s);
 923                         return -EFAULT;
 924                 }
 925         }
 926
 927         /* Check for loops */
 928         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 929                 if (newinfo->hook_entry[i])
 930                         if (check_chainloops(newinfo->hook_entry[i],
 931                            cl_s, udc_cnt, i, newinfo->entries)) {
 932                                 vfree(cl_s);
 933                                 return -EINVAL;
 934                         }
 935
 936         /* we now know the following (along with E=mc²):
 937          *  - the nr of entries in each chain is right
 938          *  - the size of the allocated space is right
 939          *  - all valid hooks have a corresponding chain
 940          *  - there are no loops
 941          *  - wrong data can still be on the level of a single entry
 942          *  - could be there are jumps to places that are not the
 943          *    beginning of a chain. This can only occur in chains that
 944          *    are not accessible from any base chains, so we don't care.
 945          */
 946
 947         /* used to know what we need to clean up if something goes wrong */
 948         i = 0;
 949         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 950            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 951         if (ret != 0) {
 952                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 953                                   ebt_cleanup_entry, net, &i);
 954         }
 955         vfree(cl_s);
 956         return ret;
 957 }
 958
 959 /* called under write_lock */
 960 static void get_counters(const struct ebt_counter *oldcounters,
 961                          struct ebt_counter *counters, unsigned int nentries)
 962 {
 963         int i, cpu;
 964         struct ebt_counter *counter_base;
 965
 966         /* counters of cpu 0 */
 967         memcpy(counters, oldcounters,
 968                sizeof(struct ebt_counter) * nentries);
 969
 970         /* add other counters to those of cpu 0 */
 971         for_each_possible_cpu(cpu) {
 972                 if (cpu == 0)
 973                         continue;
 974                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 975                 for (i = 0; i < nentries; i++) {
 976                         counters[i].pcnt += counter_base[i].pcnt;
 977                         counters[i].bcnt += counter_base[i].bcnt;
 978                 }
 979         }
 980 }
 981
 982 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 983                               struct ebt_table_info *newinfo)
 984 {
 985         int ret, i;
 986         struct ebt_counter *counterstmp = NULL;
 987         /* used to be able to unlock earlier */
 988         struct ebt_table_info *table;
 989         struct ebt_table *t;
 990
 991         /* the user wants counters back
 992          * the check on the size is done later, when we have the lock
 993          */
 994         if (repl->num_counters) {
 995                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 996                 counterstmp = vmalloc(size);
 997                 if (!counterstmp)
 998                         return -ENOMEM;
 999         }
1000
1001         newinfo->chainstack = NULL;
1002         ret = ebt_verify_pointers(repl, newinfo);
1003         if (ret != 0)
1004                 goto free_counterstmp;
1005
1006         ret = translate_table(net, repl->name, newinfo);
1007
1008         if (ret != 0)
1009                 goto free_counterstmp;
1010
1011         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1012         if (!t) {
1013                 ret = -ENOENT;
1014                 goto free_iterate;
1015         }
1016
1017         /* the table doesn't like it */
1018         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1019                 goto free_unlock;
1020
1021         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1022                 BUGPRINT("Wrong nr. of counters requested\n");
1023                 ret = -EINVAL;
1024                 goto free_unlock;
1025         }
1026
1027         /* we have the mutex lock, so no danger in reading this pointer */
1028         table = t->private;
1029         /* make sure the table can only be rmmod'ed if it contains no rules */
1030         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1031                 ret = -ENOENT;
1032                 goto free_unlock;
1033         } else if (table->nentries && !newinfo->nentries)
1034                 module_put(t->me);
1035         /* we need an atomic snapshot of the counters */
1036         write_lock_bh(&t->lock);
1037         if (repl->num_counters)
1038                 get_counters(t->private->counters, counterstmp,
1039                    t->private->nentries);
1040
1041         t->private = newinfo;
1042         write_unlock_bh(&t->lock);
1043         mutex_unlock(&ebt_mutex);
1044         /* so, a user can change the chains while having messed up her counter
1045          * allocation. Only reason why this is done is because this way the lock
1046          * is held only once, while this doesn't bring the kernel into a
1047          * dangerous state.
1048          */
1049         if (repl->num_counters &&
1050            copy_to_user(repl->counters, counterstmp,
1051            repl->num_counters * sizeof(struct ebt_counter))) {
1052                 /* Silent error, can't fail, new table is already in place */
1053                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1054         }
1055
1056         /* decrease module count and free resources */
1057         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1058                           ebt_cleanup_entry, net, NULL);
1059
1060         vfree(table->entries);
1061         if (table->chainstack) {
1062                 for_each_possible_cpu(i)
1063                         vfree(table->chainstack[i]);
1064                 vfree(table->chainstack);
1065         }
1066         vfree(table);
1067
1068         vfree(counterstmp);
1069
1070 #ifdef CONFIG_AUDIT
1071         if (audit_enabled) {
1072                 struct audit_buffer *ab;
1073
1074                 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1075                                      AUDIT_NETFILTER_CFG);
1076                 if (ab) {
1077                         audit_log_format(ab, "table=%s family=%u entries=%u",
1078                                          repl->name, AF_BRIDGE, repl->nentries);
1079                         audit_log_end(ab);
1080                 }
1081         }
1082 #endif
1083         return ret;
1084
1085 free_unlock:
1086         mutex_unlock(&ebt_mutex);
1087 free_iterate:
1088         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1089                           ebt_cleanup_entry, net, NULL);
1090 free_counterstmp:
1091         vfree(counterstmp);
1092         /* can be initialized in translate_table() */
1093         if (newinfo->chainstack) {
1094                 for_each_possible_cpu(i)
1095                         vfree(newinfo->chainstack[i]);
1096                 vfree(newinfo->chainstack);
1097         }
1098         return ret;
1099 }
1100
1101 /* replace the table */
1102 static int do_replace(struct net *net, const void __user *user,
1103                       unsigned int len)
1104 {
1105         int ret, countersize;
1106         struct ebt_table_info *newinfo;
1107         struct ebt_replace tmp;
1108
1109         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1110                 return -EFAULT;
1111
1112         if (len != sizeof(tmp) + tmp.entries_size) {
1113                 BUGPRINT("Wrong len argument\n");
1114                 return -EINVAL;
1115         }
1116
1117         if (tmp.entries_size == 0) {
1118                 BUGPRINT("Entries_size never zero\n");
1119                 return -EINVAL;
1120         }
1121         /* overflow check */
1122         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1123                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1124                 return -ENOMEM;
1125         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1126                 return -ENOMEM;
1127
1128         tmp.name[sizeof(tmp.name) - 1] = 0;
1129
1130         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1131         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1132         if (!newinfo)
1133                 return -ENOMEM;
1134
1135         if (countersize)
1136                 memset(newinfo->counters, 0, countersize);
1137
1138         newinfo->entries = vmalloc(tmp.entries_size);
1139         if (!newinfo->entries) {
1140                 ret = -ENOMEM;
1141                 goto free_newinfo;
1142         }
1143         if (copy_from_user(
1144            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1145                 BUGPRINT("Couldn't copy entries from userspace\n");
1146                 ret = -EFAULT;
1147                 goto free_entries;
1148         }
1149
1150         ret = do_replace_finish(net, &tmp, newinfo);
1151         if (ret == 0)
1152                 return ret;
1153 free_entries:
1154         vfree(newinfo->entries);
1155 free_newinfo:
1156         vfree(newinfo);
1157         return ret;
1158 }
1159
1160 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1161 {
1162         int i;
1163
1164         mutex_lock(&ebt_mutex);
1165         list_del(&table->list);
1166         mutex_unlock(&ebt_mutex);
1167         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1168                           ebt_cleanup_entry, net, NULL);
1169         if (table->private->nentries)
1170                 module_put(table->me);
1171         vfree(table->private->entries);
1172         if (table->private->chainstack) {
1173                 for_each_possible_cpu(i)
1174                         vfree(table->private->chainstack[i]);
1175                 vfree(table->private->chainstack);
1176         }
1177         vfree(table->private);
1178         kfree(table);
1179 }
1180
1181 struct ebt_table *
1182 ebt_register_table(struct net *net, const struct ebt_table *input_table,
1183                    const struct nf_hook_ops *ops)
1184 {
1185         struct ebt_table_info *newinfo;
1186         struct ebt_table *t, *table;
1187         struct ebt_replace_kernel *repl;
1188         int ret, i, countersize;
1189         void *p;
1190
1191         if (input_table == NULL || (repl = input_table->table) == NULL ||
1192             repl->entries == NULL || repl->entries_size == 0 ||
1193             repl->counters != NULL || input_table->private != NULL) {
1194                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1195                 return ERR_PTR(-EINVAL);
1196         }
1197
1198         /* Don't add one table to multiple lists. */
1199         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1200         if (!table) {
1201                 ret = -ENOMEM;
1202                 goto out;
1203         }
1204
1205         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1206         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1207         ret = -ENOMEM;
1208         if (!newinfo)
1209                 goto free_table;
1210
1211         p = vmalloc(repl->entries_size);
1212         if (!p)
1213                 goto free_newinfo;
1214
1215         memcpy(p, repl->entries, repl->entries_size);
1216         newinfo->entries = p;
1217
1218         newinfo->entries_size = repl->entries_size;
1219         newinfo->nentries = repl->nentries;
1220
1221         if (countersize)
1222                 memset(newinfo->counters, 0, countersize);
1223
1224         /* fill in newinfo and parse the entries */
1225         newinfo->chainstack = NULL;
1226         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1227                 if ((repl->valid_hooks & (1 << i)) == 0)
1228                         newinfo->hook_entry[i] = NULL;
1229                 else
1230                         newinfo->hook_entry[i] = p +
1231                                 ((char *)repl->hook_entry[i] - repl->entries);
1232         }
1233         ret = translate_table(net, repl->name, newinfo);
1234         if (ret != 0) {
1235                 BUGPRINT("Translate_table failed\n");
1236                 goto free_chainstack;
1237         }
1238
1239         if (table->check && table->check(newinfo, table->valid_hooks)) {
1240                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1241                 ret = -EINVAL;
1242                 goto free_chainstack;
1243         }
1244
1245         table->private = newinfo;
1246         rwlock_init(&table->lock);
1247         mutex_lock(&ebt_mutex);
1248         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1249                 if (strcmp(t->name, table->name) == 0) {
1250                         ret = -EEXIST;
1251                         BUGPRINT("Table name already exists\n");
1252                         goto free_unlock;
1253                 }
1254         }
1255
1256         /* Hold a reference count if the chains aren't empty */
1257         if (newinfo->nentries && !try_module_get(table->me)) {
1258                 ret = -ENOENT;
1259                 goto free_unlock;
1260         }
1261         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1262         mutex_unlock(&ebt_mutex);
1263
1264         if (!ops)
1265                 return table;
1266
1267         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1268         if (ret) {
1269                 __ebt_unregister_table(net, table);
1270                 return ERR_PTR(ret);
1271         }
1272
1273         return table;
1274 free_unlock:
1275         mutex_unlock(&ebt_mutex);
1276 free_chainstack:
1277         if (newinfo->chainstack) {
1278                 for_each_possible_cpu(i)
1279                         vfree(newinfo->chainstack[i]);
1280                 vfree(newinfo->chainstack);
1281         }
1282         vfree(newinfo->entries);
1283 free_newinfo:
1284         vfree(newinfo);
1285 free_table:
1286         kfree(table);
1287 out:
1288         return ERR_PTR(ret);
1289 }
1290
1291 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1292                           const struct nf_hook_ops *ops)
1293 {
1294         if (ops)
1295                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1296         __ebt_unregister_table(net, table);
1297 }
1298
1299 /* userspace just supplied us with counters */
1300 static int do_update_counters(struct net *net, const char *name,
1301                                 struct ebt_counter __user *counters,
1302                                 unsigned int num_counters,
1303                                 const void __user *user, unsigned int len)
1304 {
1305         int i, ret;
1306         struct ebt_counter *tmp;
1307         struct ebt_table *t;
1308
1309         if (num_counters == 0)
1310                 return -EINVAL;
1311
1312         tmp = vmalloc(num_counters * sizeof(*tmp));
1313         if (!tmp)
1314                 return -ENOMEM;
1315
1316         t = find_table_lock(net, name, &ret, &ebt_mutex);
1317         if (!t)
1318                 goto free_tmp;
1319
1320         if (num_counters != t->private->nentries) {
1321                 BUGPRINT("Wrong nr of counters\n");
1322                 ret = -EINVAL;
1323                 goto unlock_mutex;
1324         }
1325
1326         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1327                 ret = -EFAULT;
1328                 goto unlock_mutex;
1329         }
1330
1331         /* we want an atomic add of the counters */
1332         write_lock_bh(&t->lock);
1333
1334         /* we add to the counters of the first cpu */
1335         for (i = 0; i < num_counters; i++) {
1336                 t->private->counters[i].pcnt += tmp[i].pcnt;
1337                 t->private->counters[i].bcnt += tmp[i].bcnt;
1338         }
1339
1340         write_unlock_bh(&t->lock);
1341         ret = 0;
1342 unlock_mutex:
1343         mutex_unlock(&ebt_mutex);
1344 free_tmp:
1345         vfree(tmp);
1346         return ret;
1347 }
1348
1349 static int update_counters(struct net *net, const void __user *user,
1350                             unsigned int len)
1351 {
1352         struct ebt_replace hlp;
1353
1354         if (copy_from_user(&hlp, user, sizeof(hlp)))
1355                 return -EFAULT;
1356
1357         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1358                 return -EINVAL;
1359
1360         return do_update_counters(net, hlp.name, hlp.counters,
1361                                 hlp.num_counters, user, len);
1362 }
1363
1364 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1365                                   const char *data, int entrysize,
1366                                   int usersize, int datasize)
1367 {
1368         char name[EBT_FUNCTION_MAXNAMELEN] = {0};
1369
1370         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1371          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1372          */
1373         strlcpy(name, _name, sizeof(name));
1374         if (copy_to_user(um, name, EBT_FUNCTION_MAXNAMELEN) ||
1375             put_user(datasize, (int __user *)(um + EBT_FUNCTION_MAXNAMELEN)) ||
1376             xt_data_to_user(um + entrysize, data, usersize, datasize))
1377                 return -EFAULT;
1378
1379         return 0;
1380 }
1381
1382 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1383                                     const char *base, char __user *ubase)
1384 {
1385         return ebt_obj_to_user(ubase + ((char *)m - base),
1386                                m->u.match->name, m->data, sizeof(*m),
1387                                m->u.match->usersize, m->match_size);
1388 }
1389
1390 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1391                                       const char *base, char __user *ubase)
1392 {
1393         return ebt_obj_to_user(ubase + ((char *)w - base),
1394                                w->u.watcher->name, w->data, sizeof(*w),
1395                                w->u.watcher->usersize, w->watcher_size);
1396 }
1397
1398 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1399                                     char __user *ubase)
1400 {
1401         int ret;
1402         char __user *hlp;
1403         const struct ebt_entry_target *t;
1404
1405         if (e->bitmask == 0) {
1406                 /* special case !EBT_ENTRY_OR_ENTRIES */
1407                 if (copy_to_user(ubase + ((char *)e - base), e,
1408                                  sizeof(struct ebt_entries)))
1409                         return -EFAULT;
1410                 return 0;
1411         }
1412
1413         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1414                 return -EFAULT;
1415
1416         hlp = ubase + (((char *)e + e->target_offset) - base);
1417         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1418
1419         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1420         if (ret != 0)
1421                 return ret;
1422         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1423         if (ret != 0)
1424                 return ret;
1425         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1426                               t->u.target->usersize, t->target_size);
1427         if (ret != 0)
1428                 return ret;
1429
1430         return 0;
1431 }
1432
1433 static int copy_counters_to_user(struct ebt_table *t,
1434                                  const struct ebt_counter *oldcounters,
1435                                  void __user *user, unsigned int num_counters,
1436                                  unsigned int nentries)
1437 {
1438         struct ebt_counter *counterstmp;
1439         int ret = 0;
1440
1441         /* userspace might not need the counters */
1442         if (num_counters == 0)
1443                 return 0;
1444
1445         if (num_counters != nentries) {
1446                 BUGPRINT("Num_counters wrong\n");
1447                 return -EINVAL;
1448         }
1449
1450         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1451         if (!counterstmp)
1452                 return -ENOMEM;
1453
1454         write_lock_bh(&t->lock);
1455         get_counters(oldcounters, counterstmp, nentries);
1456         write_unlock_bh(&t->lock);
1457
1458         if (copy_to_user(user, counterstmp,
1459            nentries * sizeof(struct ebt_counter)))
1460                 ret = -EFAULT;
1461         vfree(counterstmp);
1462         return ret;
1463 }
1464
1465 /* called with ebt_mutex locked */
1466 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1467                                    const int *len, int cmd)
1468 {
1469         struct ebt_replace tmp;
1470         const struct ebt_counter *oldcounters;
1471         unsigned int entries_size, nentries;
1472         int ret;
1473         char *entries;
1474
1475         if (cmd == EBT_SO_GET_ENTRIES) {
1476                 entries_size = t->private->entries_size;
1477                 nentries = t->private->nentries;
1478                 entries = t->private->entries;
1479                 oldcounters = t->private->counters;
1480         } else {
1481                 entries_size = t->table->entries_size;
1482                 nentries = t->table->nentries;
1483                 entries = t->table->entries;
1484                 oldcounters = t->table->counters;
1485         }
1486
1487         if (copy_from_user(&tmp, user, sizeof(tmp)))
1488                 return -EFAULT;
1489
1490         if (*len != sizeof(struct ebt_replace) + entries_size +
1491            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1492                 return -EINVAL;
1493
1494         if (tmp.nentries != nentries) {
1495                 BUGPRINT("Nentries wrong\n");
1496                 return -EINVAL;
1497         }
1498
1499         if (tmp.entries_size != entries_size) {
1500                 BUGPRINT("Wrong size\n");
1501                 return -EINVAL;
1502         }
1503
1504         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1505                                         tmp.num_counters, nentries);
1506         if (ret)
1507                 return ret;
1508
1509         /* set the match/watcher/target names right */
1510         return EBT_ENTRY_ITERATE(entries, entries_size,
1511            ebt_entry_to_user, entries, tmp.entries);
1512 }
1513
1514 static int do_ebt_set_ctl(struct sock *sk,
1515         int cmd, void __user *user, unsigned int len)
1516 {
1517         int ret;
1518         struct net *net = sock_net(sk);
1519
1520         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1521                 return -EPERM;
1522
1523         switch (cmd) {
1524         case EBT_SO_SET_ENTRIES:
1525                 ret = do_replace(net, user, len);
1526                 break;
1527         case EBT_SO_SET_COUNTERS:
1528                 ret = update_counters(net, user, len);
1529                 break;
1530         default:
1531                 ret = -EINVAL;
1532         }
1533         return ret;
1534 }
1535
1536 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1537 {
1538         int ret;
1539         struct ebt_replace tmp;
1540         struct ebt_table *t;
1541         struct net *net = sock_net(sk);
1542
1543         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1544                 return -EPERM;
1545
1546         if (copy_from_user(&tmp, user, sizeof(tmp)))
1547                 return -EFAULT;
1548
1549         tmp.name[sizeof(tmp.name) - 1] = '\0';
1550
1551         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1552         if (!t)
1553                 return ret;
1554
1555         switch (cmd) {
1556         case EBT_SO_GET_INFO:
1557         case EBT_SO_GET_INIT_INFO:
1558                 if (*len != sizeof(struct ebt_replace)) {
1559                         ret = -EINVAL;
1560                         mutex_unlock(&ebt_mutex);
1561                         break;
1562                 }
1563                 if (cmd == EBT_SO_GET_INFO) {
1564                         tmp.nentries = t->private->nentries;
1565                         tmp.entries_size = t->private->entries_size;
1566                         tmp.valid_hooks = t->valid_hooks;
1567                 } else {
1568                         tmp.nentries = t->table->nentries;
1569                         tmp.entries_size = t->table->entries_size;
1570                         tmp.valid_hooks = t->table->valid_hooks;
1571                 }
1572                 mutex_unlock(&ebt_mutex);
1573                 if (copy_to_user(user, &tmp, *len) != 0) {
1574                         BUGPRINT("c2u Didn't work\n");
1575                         ret = -EFAULT;
1576                         break;
1577                 }
1578                 ret = 0;
1579                 break;
1580
1581         case EBT_SO_GET_ENTRIES:
1582         case EBT_SO_GET_INIT_ENTRIES:
1583                 ret = copy_everything_to_user(t, user, len, cmd);
1584                 mutex_unlock(&ebt_mutex);
1585                 break;
1586
1587         default:
1588                 mutex_unlock(&ebt_mutex);
1589                 ret = -EINVAL;
1590         }
1591
1592         return ret;
1593 }
1594
1595 #ifdef CONFIG_COMPAT
1596 /* 32 bit-userspace compatibility definitions. */
1597 struct compat_ebt_replace {
1598         char name[EBT_TABLE_MAXNAMELEN];
1599         compat_uint_t valid_hooks;
1600         compat_uint_t nentries;
1601         compat_uint_t entries_size;
1602         /* start of the chains */
1603         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1604         /* nr of counters userspace expects back */
1605         compat_uint_t num_counters;
1606         /* where the kernel will put the old counters. */
1607         compat_uptr_t counters;
1608         compat_uptr_t entries;
1609 };
1610
1611 /* struct ebt_entry_match, _target and _watcher have same layout */
1612 struct compat_ebt_entry_mwt {
1613         union {
1614                 char name[EBT_FUNCTION_MAXNAMELEN];
1615                 compat_uptr_t ptr;
1616         } u;
1617         compat_uint_t match_size;
1618         compat_uint_t data[0];
1619 };
1620
1621 /* account for possible padding between match_size and ->data */
1622 static int ebt_compat_entry_padsize(void)
1623 {
1624         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1625                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1626         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1627                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1628 }
1629
1630 static int ebt_compat_match_offset(const struct xt_match *match,
1631                                    unsigned int userlen)
1632 {
1633         /* ebt_among needs special handling. The kernel .matchsize is
1634          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1635          * value is expected.
1636          * Example: userspace sends 4500, ebt_among.c wants 4504.
1637          */
1638         if (unlikely(match->matchsize == -1))
1639                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1640         return xt_compat_match_offset(match);
1641 }
1642
1643 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1644                                 unsigned int *size)
1645 {
1646         const struct xt_match *match = m->u.match;
1647         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1648         int off = ebt_compat_match_offset(match, m->match_size);
1649         compat_uint_t msize = m->match_size - off;
1650
1651         BUG_ON(off >= m->match_size);
1652
1653         if (copy_to_user(cm->u.name, match->name,
1654             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1655                 return -EFAULT;
1656
1657         if (match->compat_to_user) {
1658                 if (match->compat_to_user(cm->data, m->data))
1659                         return -EFAULT;
1660         } else {
1661                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize))
1662                         return -EFAULT;
1663         }
1664
1665         *size -= ebt_compat_entry_padsize() + off;
1666         *dstptr = cm->data;
1667         *dstptr += msize;
1668         return 0;
1669 }
1670
1671 static int compat_target_to_user(struct ebt_entry_target *t,
1672                                  void __user **dstptr,
1673                                  unsigned int *size)
1674 {
1675         const struct xt_target *target = t->u.target;
1676         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1677         int off = xt_compat_target_offset(target);
1678         compat_uint_t tsize = t->target_size - off;
1679
1680         BUG_ON(off >= t->target_size);
1681
1682         if (copy_to_user(cm->u.name, target->name,
1683             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1684                 return -EFAULT;
1685
1686         if (target->compat_to_user) {
1687                 if (target->compat_to_user(cm->data, t->data))
1688                         return -EFAULT;
1689         } else {
1690                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize))
1691                         return -EFAULT;
1692         }
1693
1694         *size -= ebt_compat_entry_padsize() + off;
1695         *dstptr = cm->data;
1696         *dstptr += tsize;
1697         return 0;
1698 }
1699
1700 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1701                                   void __user **dstptr,
1702                                   unsigned int *size)
1703 {
1704         return compat_target_to_user((struct ebt_entry_target *)w,
1705                                                         dstptr, size);
1706 }
1707
1708 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1709                                 unsigned int *size)
1710 {
1711         struct ebt_entry_target *t;
1712         struct ebt_entry __user *ce;
1713         u32 watchers_offset, target_offset, next_offset;
1714         compat_uint_t origsize;
1715         int ret;
1716
1717         if (e->bitmask == 0) {
1718                 if (*size < sizeof(struct ebt_entries))
1719                         return -EINVAL;
1720                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1721                         return -EFAULT;
1722
1723                 *dstptr += sizeof(struct ebt_entries);
1724                 *size -= sizeof(struct ebt_entries);
1725                 return 0;
1726         }
1727
1728         if (*size < sizeof(*ce))
1729                 return -EINVAL;
1730
1731         ce = *dstptr;
1732         if (copy_to_user(ce, e, sizeof(*ce)))
1733                 return -EFAULT;
1734
1735         origsize = *size;
1736         *dstptr += sizeof(*ce);
1737
1738         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1739         if (ret)
1740                 return ret;
1741         watchers_offset = e->watchers_offset - (origsize - *size);
1742
1743         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1744         if (ret)
1745                 return ret;
1746         target_offset = e->target_offset - (origsize - *size);
1747
1748         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1749
1750         ret = compat_target_to_user(t, dstptr, size);
1751         if (ret)
1752                 return ret;
1753         next_offset = e->next_offset - (origsize - *size);
1754
1755         if (put_user(watchers_offset, &ce->watchers_offset) ||
1756             put_user(target_offset, &ce->target_offset) ||
1757             put_user(next_offset, &ce->next_offset))
1758                 return -EFAULT;
1759
1760         *size -= sizeof(*ce);
1761         return 0;
1762 }
1763
1764 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1765 {
1766         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1767         *off += ebt_compat_entry_padsize();
1768         return 0;
1769 }
1770
1771 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1772 {
1773         *off += xt_compat_target_offset(w->u.watcher);
1774         *off += ebt_compat_entry_padsize();
1775         return 0;
1776 }
1777
1778 static int compat_calc_entry(const struct ebt_entry *e,
1779                              const struct ebt_table_info *info,
1780                              const void *base,
1781                              struct compat_ebt_replace *newinfo)
1782 {
1783         const struct ebt_entry_target *t;
1784         unsigned int entry_offset;
1785         int off, ret, i;
1786
1787         if (e->bitmask == 0)
1788                 return 0;
1789
1790         off = 0;
1791         entry_offset = (void *)e - base;
1792
1793         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1794         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1795
1796         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1797
1798         off += xt_compat_target_offset(t->u.target);
1799         off += ebt_compat_entry_padsize();
1800
1801         newinfo->entries_size -= off;
1802
1803         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1804         if (ret)
1805                 return ret;
1806
1807         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1808                 const void *hookptr = info->hook_entry[i];
1809                 if (info->hook_entry[i] &&
1810                     (e < (struct ebt_entry *)(base - hookptr))) {
1811                         newinfo->hook_entry[i] -= off;
1812                         pr_debug("0x%08X -> 0x%08X\n",
1813                                         newinfo->hook_entry[i] + off,
1814                                         newinfo->hook_entry[i]);
1815                 }
1816         }
1817
1818         return 0;
1819 }
1820
1821
1822 static int compat_table_info(const struct ebt_table_info *info,
1823                              struct compat_ebt_replace *newinfo)
1824 {
1825         unsigned int size = info->entries_size;
1826         const void *entries = info->entries;
1827
1828         newinfo->entries_size = size;
1829
1830         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1831         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1832                                                         entries, newinfo);
1833 }
1834
1835 static int compat_copy_everything_to_user(struct ebt_table *t,
1836                                           void __user *user, int *len, int cmd)
1837 {
1838         struct compat_ebt_replace repl, tmp;
1839         struct ebt_counter *oldcounters;
1840         struct ebt_table_info tinfo;
1841         int ret;
1842         void __user *pos;
1843
1844         memset(&tinfo, 0, sizeof(tinfo));
1845
1846         if (cmd == EBT_SO_GET_ENTRIES) {
1847                 tinfo.entries_size = t->private->entries_size;
1848                 tinfo.nentries = t->private->nentries;
1849                 tinfo.entries = t->private->entries;
1850                 oldcounters = t->private->counters;
1851         } else {
1852                 tinfo.entries_size = t->table->entries_size;
1853                 tinfo.nentries = t->table->nentries;
1854                 tinfo.entries = t->table->entries;
1855                 oldcounters = t->table->counters;
1856         }
1857
1858         if (copy_from_user(&tmp, user, sizeof(tmp)))
1859                 return -EFAULT;
1860
1861         if (tmp.nentries != tinfo.nentries ||
1862            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1863                 return -EINVAL;
1864
1865         memcpy(&repl, &tmp, sizeof(repl));
1866         if (cmd == EBT_SO_GET_ENTRIES)
1867                 ret = compat_table_info(t->private, &repl);
1868         else
1869                 ret = compat_table_info(&tinfo, &repl);
1870         if (ret)
1871                 return ret;
1872
1873         if (*len != sizeof(tmp) + repl.entries_size +
1874            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1875                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1876                                 *len, tinfo.entries_size, repl.entries_size);
1877                 return -EINVAL;
1878         }
1879
1880         /* userspace might not need the counters */
1881         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1882                                         tmp.num_counters, tinfo.nentries);
1883         if (ret)
1884                 return ret;
1885
1886         pos = compat_ptr(tmp.entries);
1887         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1888                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1889 }
1890
1891 struct ebt_entries_buf_state {
1892         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1893         u32 buf_kern_len;       /* total size of kernel buffer */
1894         u32 buf_kern_offset;    /* amount of data copied so far */
1895         u32 buf_user_offset;    /* read position in userspace buffer */
1896 };
1897
1898 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1899 {
1900         state->buf_kern_offset += sz;
1901         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1902 }
1903
1904 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1905                        void *data, unsigned int sz)
1906 {
1907         if (state->buf_kern_start == NULL)
1908                 goto count_only;
1909
1910         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1911
1912         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1913
1914  count_only:
1915         state->buf_user_offset += sz;
1916         return ebt_buf_count(state, sz);
1917 }
1918
1919 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1920 {
1921         char *b = state->buf_kern_start;
1922
1923         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1924
1925         if (b != NULL && sz > 0)
1926                 memset(b + state->buf_kern_offset, 0, sz);
1927         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1928         return ebt_buf_count(state, sz);
1929 }
1930
1931 enum compat_mwt {
1932         EBT_COMPAT_MATCH,
1933         EBT_COMPAT_WATCHER,
1934         EBT_COMPAT_TARGET,
1935 };
1936
1937 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1938                                 enum compat_mwt compat_mwt,
1939                                 struct ebt_entries_buf_state *state,
1940                                 const unsigned char *base)
1941 {
1942         char name[EBT_FUNCTION_MAXNAMELEN];
1943         struct xt_match *match;
1944         struct xt_target *wt;
1945         void *dst = NULL;
1946         int off, pad = 0;
1947         unsigned int size_kern, match_size = mwt->match_size;
1948
1949         strlcpy(name, mwt->u.name, sizeof(name));
1950
1951         if (state->buf_kern_start)
1952                 dst = state->buf_kern_start + state->buf_kern_offset;
1953
1954         switch (compat_mwt) {
1955         case EBT_COMPAT_MATCH:
1956                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1957                 if (IS_ERR(match))
1958                         return PTR_ERR(match);
1959
1960                 off = ebt_compat_match_offset(match, match_size);
1961                 if (dst) {
1962                         if (match->compat_from_user)
1963                                 match->compat_from_user(dst, mwt->data);
1964                         else
1965                                 memcpy(dst, mwt->data, match_size);
1966                 }
1967
1968                 size_kern = match->matchsize;
1969                 if (unlikely(size_kern == -1))
1970                         size_kern = match_size;
1971                 module_put(match->me);
1972                 break;
1973         case EBT_COMPAT_WATCHER: /* fallthrough */
1974         case EBT_COMPAT_TARGET:
1975                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1976                 if (IS_ERR(wt))
1977                         return PTR_ERR(wt);
1978                 off = xt_compat_target_offset(wt);
1979
1980                 if (dst) {
1981                         if (wt->compat_from_user)
1982                                 wt->compat_from_user(dst, mwt->data);
1983                         else
1984                                 memcpy(dst, mwt->data, match_size);
1985                 }
1986
1987                 size_kern = wt->targetsize;
1988                 module_put(wt->me);
1989                 break;
1990
1991         default:
1992                 return -EINVAL;
1993         }
1994
1995         state->buf_kern_offset += match_size + off;
1996         state->buf_user_offset += match_size;
1997         pad = XT_ALIGN(size_kern) - size_kern;
1998
1999         if (pad > 0 && dst) {
2000                 BUG_ON(state->buf_kern_len <= pad);
2001                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
2002                 memset(dst + size_kern, 0, pad);
2003         }
2004         return off + match_size;
2005 }
2006
2007 /* return size of all matches, watchers or target, including necessary
2008  * alignment and padding.
2009  */
2010 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2011                         unsigned int size_left, enum compat_mwt type,
2012                         struct ebt_entries_buf_state *state, const void *base)
2013 {
2014         int growth = 0;
2015         char *buf;
2016
2017         if (size_left == 0)
2018                 return 0;
2019
2020         buf = (char *) match32;
2021
2022         while (size_left >= sizeof(*match32)) {
2023                 struct ebt_entry_match *match_kern;
2024                 int ret;
2025
2026                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2027                 if (match_kern) {
2028                         char *tmp;
2029                         tmp = state->buf_kern_start + state->buf_kern_offset;
2030                         match_kern = (struct ebt_entry_match *) tmp;
2031                 }
2032                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2033                 if (ret < 0)
2034                         return ret;
2035                 size_left -= sizeof(*match32);
2036
2037                 /* add padding before match->data (if any) */
2038                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2039                 if (ret < 0)
2040                         return ret;
2041
2042                 if (match32->match_size > size_left)
2043                         return -EINVAL;
2044
2045                 size_left -= match32->match_size;
2046
2047                 ret = compat_mtw_from_user(match32, type, state, base);
2048                 if (ret < 0)
2049                         return ret;
2050
2051                 BUG_ON(ret < match32->match_size);
2052                 growth += ret - match32->match_size;
2053                 growth += ebt_compat_entry_padsize();
2054
2055                 buf += sizeof(*match32);
2056                 buf += match32->match_size;
2057
2058                 if (match_kern)
2059                         match_kern->match_size = ret;
2060
2061                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2062                 match32 = (struct compat_ebt_entry_mwt *) buf;
2063         }
2064
2065         return growth;
2066 }
2067
2068 /* called for all ebt_entry structures. */
2069 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2070                           unsigned int *total,
2071                           struct ebt_entries_buf_state *state)
2072 {
2073         unsigned int i, j, startoff, new_offset = 0;
2074         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2075         unsigned int offsets[4];
2076         unsigned int *offsets_update = NULL;
2077         int ret;
2078         char *buf_start;
2079
2080         if (*total < sizeof(struct ebt_entries))
2081                 return -EINVAL;
2082
2083         if (!entry->bitmask) {
2084                 *total -= sizeof(struct ebt_entries);
2085                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2086         }
2087         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2088                 return -EINVAL;
2089
2090         startoff = state->buf_user_offset;
2091         /* pull in most part of ebt_entry, it does not need to be changed. */
2092         ret = ebt_buf_add(state, entry,
2093                         offsetof(struct ebt_entry, watchers_offset));
2094         if (ret < 0)
2095                 return ret;
2096
2097         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2098         memcpy(&offsets[1], &entry->watchers_offset,
2099                         sizeof(offsets) - sizeof(offsets[0]));
2100
2101         if (state->buf_kern_start) {
2102                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2103                 offsets_update = (unsigned int *) buf_start;
2104         }
2105         ret = ebt_buf_add(state, &offsets[1],
2106                         sizeof(offsets) - sizeof(offsets[0]));
2107         if (ret < 0)
2108                 return ret;
2109         buf_start = (char *) entry;
2110         /* 0: matches offset, always follows ebt_entry.
2111          * 1: watchers offset, from ebt_entry structure
2112          * 2: target offset, from ebt_entry structure
2113          * 3: next ebt_entry offset, from ebt_entry structure
2114          *
2115          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2116          */
2117         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2118                 struct compat_ebt_entry_mwt *match32;
2119                 unsigned int size;
2120                 char *buf = buf_start;
2121
2122                 buf = buf_start + offsets[i];
2123                 if (offsets[i] > offsets[j])
2124                         return -EINVAL;
2125
2126                 match32 = (struct compat_ebt_entry_mwt *) buf;
2127                 size = offsets[j] - offsets[i];
2128                 ret = ebt_size_mwt(match32, size, i, state, base);
2129                 if (ret < 0)
2130                         return ret;
2131                 new_offset += ret;
2132                 if (offsets_update && new_offset) {
2133                         pr_debug("change offset %d to %d\n",
2134                                 offsets_update[i], offsets[j] + new_offset);
2135                         offsets_update[i] = offsets[j] + new_offset;
2136                 }
2137         }
2138
2139         if (state->buf_kern_start == NULL) {
2140                 unsigned int offset = buf_start - (char *) base;
2141
2142                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2143                 if (ret < 0)
2144                         return ret;
2145         }
2146
2147         startoff = state->buf_user_offset - startoff;
2148
2149         BUG_ON(*total < startoff);
2150         *total -= startoff;
2151         return 0;
2152 }
2153
2154 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2155  * It might need more memory when copied to a 64 bit kernel in case
2156  * userspace is 32-bit. So, first task: find out how much memory is needed.
2157  *
2158  * Called before validation is performed.
2159  */
2160 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2161                                 struct ebt_entries_buf_state *state)
2162 {
2163         unsigned int size_remaining = size_user;
2164         int ret;
2165
2166         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2167                                         &size_remaining, state);
2168         if (ret < 0)
2169                 return ret;
2170
2171         WARN_ON(size_remaining);
2172         return state->buf_kern_offset;
2173 }
2174
2175
2176 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2177                                             void __user *user, unsigned int len)
2178 {
2179         struct compat_ebt_replace tmp;
2180         int i;
2181
2182         if (len < sizeof(tmp))
2183                 return -EINVAL;
2184
2185         if (copy_from_user(&tmp, user, sizeof(tmp)))
2186                 return -EFAULT;
2187
2188         if (len != sizeof(tmp) + tmp.entries_size)
2189                 return -EINVAL;
2190
2191         if (tmp.entries_size == 0)
2192                 return -EINVAL;
2193
2194         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2195                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2196                 return -ENOMEM;
2197         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2198                 return -ENOMEM;
2199
2200         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2201
2202         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2203         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2204                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2205
2206         repl->num_counters = tmp.num_counters;
2207         repl->counters = compat_ptr(tmp.counters);
2208         repl->entries = compat_ptr(tmp.entries);
2209         return 0;
2210 }
2211
2212 static int compat_do_replace(struct net *net, void __user *user,
2213                              unsigned int len)
2214 {
2215         int ret, i, countersize, size64;
2216         struct ebt_table_info *newinfo;
2217         struct ebt_replace tmp;
2218         struct ebt_entries_buf_state state;
2219         void *entries_tmp;
2220
2221         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2222         if (ret) {
2223                 /* try real handler in case userland supplied needed padding */
2224                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2225                         ret = 0;
2226                 return ret;
2227         }
2228
2229         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2230         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2231         if (!newinfo)
2232                 return -ENOMEM;
2233
2234         if (countersize)
2235                 memset(newinfo->counters, 0, countersize);
2236
2237         memset(&state, 0, sizeof(state));
2238
2239         newinfo->entries = vmalloc(tmp.entries_size);
2240         if (!newinfo->entries) {
2241                 ret = -ENOMEM;
2242                 goto free_newinfo;
2243         }
2244         if (copy_from_user(
2245            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2246                 ret = -EFAULT;
2247                 goto free_entries;
2248         }
2249
2250         entries_tmp = newinfo->entries;
2251
2252         xt_compat_lock(NFPROTO_BRIDGE);
2253
2254         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2255         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2256         if (ret < 0)
2257                 goto out_unlock;
2258
2259         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2260                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2261                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2262
2263         size64 = ret;
2264         newinfo->entries = vmalloc(size64);
2265         if (!newinfo->entries) {
2266                 vfree(entries_tmp);
2267                 ret = -ENOMEM;
2268                 goto out_unlock;
2269         }
2270
2271         memset(&state, 0, sizeof(state));
2272         state.buf_kern_start = newinfo->entries;
2273         state.buf_kern_len = size64;
2274
2275         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2276         BUG_ON(ret < 0);        /* parses same data again */
2277
2278         vfree(entries_tmp);
2279         tmp.entries_size = size64;
2280
2281         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2282                 char __user *usrptr;
2283                 if (tmp.hook_entry[i]) {
2284                         unsigned int delta;
2285                         usrptr = (char __user *) tmp.hook_entry[i];
2286                         delta = usrptr - tmp.entries;
2287                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2288                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2289                 }
2290         }
2291
2292         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2293         xt_compat_unlock(NFPROTO_BRIDGE);
2294
2295         ret = do_replace_finish(net, &tmp, newinfo);
2296         if (ret == 0)
2297                 return ret;
2298 free_entries:
2299         vfree(newinfo->entries);
2300 free_newinfo:
2301         vfree(newinfo);
2302         return ret;
2303 out_unlock:
2304         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2305         xt_compat_unlock(NFPROTO_BRIDGE);
2306         goto free_entries;
2307 }
2308
2309 static int compat_update_counters(struct net *net, void __user *user,
2310                                   unsigned int len)
2311 {
2312         struct compat_ebt_replace hlp;
2313
2314         if (copy_from_user(&hlp, user, sizeof(hlp)))
2315                 return -EFAULT;
2316
2317         /* try real handler in case userland supplied needed padding */
2318         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2319                 return update_counters(net, user, len);
2320
2321         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2322                                         hlp.num_counters, user, len);
2323 }
2324
2325 static int compat_do_ebt_set_ctl(struct sock *sk,
2326                 int cmd, void __user *user, unsigned int len)
2327 {
2328         int ret;
2329         struct net *net = sock_net(sk);
2330
2331         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2332                 return -EPERM;
2333
2334         switch (cmd) {
2335         case EBT_SO_SET_ENTRIES:
2336                 ret = compat_do_replace(net, user, len);
2337                 break;
2338         case EBT_SO_SET_COUNTERS:
2339                 ret = compat_update_counters(net, user, len);
2340                 break;
2341         default:
2342                 ret = -EINVAL;
2343         }
2344         return ret;
2345 }
2346
2347 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2348                 void __user *user, int *len)
2349 {
2350         int ret;
2351         struct compat_ebt_replace tmp;
2352         struct ebt_table *t;
2353         struct net *net = sock_net(sk);
2354
2355         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2356                 return -EPERM;
2357
2358         /* try real handler in case userland supplied needed padding */
2359         if ((cmd == EBT_SO_GET_INFO ||
2360              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2361                         return do_ebt_get_ctl(sk, cmd, user, len);
2362
2363         if (copy_from_user(&tmp, user, sizeof(tmp)))
2364                 return -EFAULT;
2365
2366         tmp.name[sizeof(tmp.name) - 1] = '\0';
2367
2368         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2369         if (!t)
2370                 return ret;
2371
2372         xt_compat_lock(NFPROTO_BRIDGE);
2373         switch (cmd) {
2374         case EBT_SO_GET_INFO:
2375                 tmp.nentries = t->private->nentries;
2376                 ret = compat_table_info(t->private, &tmp);
2377                 if (ret)
2378                         goto out;
2379                 tmp.valid_hooks = t->valid_hooks;
2380
2381                 if (copy_to_user(user, &tmp, *len) != 0) {
2382                         ret = -EFAULT;
2383                         break;
2384                 }
2385                 ret = 0;
2386                 break;
2387         case EBT_SO_GET_INIT_INFO:
2388                 tmp.nentries = t->table->nentries;
2389                 tmp.entries_size = t->table->entries_size;
2390                 tmp.valid_hooks = t->table->valid_hooks;
2391
2392                 if (copy_to_user(user, &tmp, *len) != 0) {
2393                         ret = -EFAULT;
2394                         break;
2395                 }
2396                 ret = 0;
2397                 break;
2398         case EBT_SO_GET_ENTRIES:
2399         case EBT_SO_GET_INIT_ENTRIES:
2400                 /* try real handler first in case of userland-side padding.
2401                  * in case we are dealing with an 'ordinary' 32 bit binary
2402                  * without 64bit compatibility padding, this will fail right
2403                  * after copy_from_user when the *len argument is validated.
2404                  *
2405                  * the compat_ variant needs to do one pass over the kernel
2406                  * data set to adjust for size differences before it the check.
2407                  */
2408                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2409                         ret = 0;
2410                 else
2411                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2412                 break;
2413         default:
2414                 ret = -EINVAL;
2415         }
2416  out:
2417         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2418         xt_compat_unlock(NFPROTO_BRIDGE);
2419         mutex_unlock(&ebt_mutex);
2420         return ret;
2421 }
2422 #endif
2423
2424 static struct nf_sockopt_ops ebt_sockopts = {
2425         .pf             = PF_INET,
2426         .set_optmin     = EBT_BASE_CTL,
2427         .set_optmax     = EBT_SO_SET_MAX + 1,
2428         .set            = do_ebt_set_ctl,
2429 #ifdef CONFIG_COMPAT
2430         .compat_set     = compat_do_ebt_set_ctl,
2431 #endif
2432         .get_optmin     = EBT_BASE_CTL,
2433         .get_optmax     = EBT_SO_GET_MAX + 1,
2434         .get            = do_ebt_get_ctl,
2435 #ifdef CONFIG_COMPAT
2436         .compat_get     = compat_do_ebt_get_ctl,
2437 #endif
2438         .owner          = THIS_MODULE,
2439 };
2440
2441 static int __init ebtables_init(void)
2442 {
2443         int ret;
2444
2445         ret = xt_register_target(&ebt_standard_target);
2446         if (ret < 0)
2447                 return ret;
2448         ret = nf_register_sockopt(&ebt_sockopts);
2449         if (ret < 0) {
2450                 xt_unregister_target(&ebt_standard_target);
2451                 return ret;
2452         }
2453
2454         printk(KERN_INFO "Ebtables v2.0 registered\n");
2455         return 0;
2456 }
2457
2458 static void __exit ebtables_fini(void)
2459 {
2460         nf_unregister_sockopt(&ebt_sockopts);
2461         xt_unregister_target(&ebt_standard_target);
2462         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2463 }
2464
2465 EXPORT_SYMBOL(ebt_register_table);
2466 EXPORT_SYMBOL(ebt_unregister_table);
2467 EXPORT_SYMBOL(ebt_do_table);
2468 module_init(ebtables_init);
2469 module_exit(ebtables_fini);
2470 MODULE_LICENSE("GPL");