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 stongly inspired on 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 <asm/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <net/sock.h>
  30 /* needed for logical [in,out]-dev filtering */
  31 #include "../br_private.h"
  32
  33 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  34                                          "report to author: "format, ## args)
  35 /* #define BUGPRINT(format, args...) */
  36
  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 #define FWINV2(bool,invflg) ((bool) ^ !!(e->invflags & invflg))
 125 /* process standard matches */
 126 static inline int
 127 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 128                 const struct net_device *in, const struct net_device *out)
 129 {
 130         const struct ethhdr *h = eth_hdr(skb);
 131         const struct net_bridge_port *p;
 132         __be16 ethproto;
 133         int verdict, i;
 134
 135         if (vlan_tx_tag_present(skb))
 136                 ethproto = htons(ETH_P_8021Q);
 137         else
 138                 ethproto = h->h_proto;
 139
 140         if (e->bitmask & EBT_802_3) {
 141                 if (FWINV2(ntohs(ethproto) >= 1536, EBT_IPROTO))
 142                         return 1;
 143         } else if (!(e->bitmask & EBT_NOPROTO) &&
 144            FWINV2(e->ethproto != ethproto, EBT_IPROTO))
 145                 return 1;
 146
 147         if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN))
 148                 return 1;
 149         if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
 150                 return 1;
 151         /* rcu_read_lock()ed by nf_hook_slow */
 152         if (in && (p = br_port_get_rcu(in)) != NULL &&
 153             FWINV2(ebt_dev_check(e->logical_in, p->br->dev), EBT_ILOGICALIN))
 154                 return 1;
 155         if (out && (p = br_port_get_rcu(out)) != NULL &&
 156             FWINV2(ebt_dev_check(e->logical_out, p->br->dev), EBT_ILOGICALOUT))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 verdict = 0;
 161                 for (i = 0; i < 6; i++)
 162                         verdict |= (h->h_source[i] ^ e->sourcemac[i]) &
 163                            e->sourcemsk[i];
 164                 if (FWINV2(verdict != 0, EBT_ISOURCE) )
 165                         return 1;
 166         }
 167         if (e->bitmask & EBT_DESTMAC) {
 168                 verdict = 0;
 169                 for (i = 0; i < 6; i++)
 170                         verdict |= (h->h_dest[i] ^ e->destmac[i]) &
 171                            e->destmsk[i];
 172                 if (FWINV2(verdict != 0, EBT_IDEST) )
 173                         return 1;
 174         }
 175         return 0;
 176 }
 177
 178 static inline __pure
 179 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 180 {
 181         return (void *)entry + entry->next_offset;
 182 }
 183
 184 /* Do some firewalling */
 185 unsigned int ebt_do_table (unsigned int hook, struct sk_buff *skb,
 186    const struct net_device *in, const struct net_device *out,
 187    struct ebt_table *table)
 188 {
 189         int i, nentries;
 190         struct ebt_entry *point;
 191         struct ebt_counter *counter_base, *cb_base;
 192         const struct ebt_entry_target *t;
 193         int verdict, sp = 0;
 194         struct ebt_chainstack *cs;
 195         struct ebt_entries *chaininfo;
 196         const char *base;
 197         const struct ebt_table_info *private;
 198         struct xt_action_param acpar;
 199
 200         acpar.family  = NFPROTO_BRIDGE;
 201         acpar.in      = in;
 202         acpar.out     = out;
 203         acpar.hotdrop = false;
 204         acpar.hooknum = hook;
 205
 206         read_lock_bh(&table->lock);
 207         private = table->private;
 208         cb_base = COUNTER_BASE(private->counters, private->nentries,
 209            smp_processor_id());
 210         if (private->chainstack)
 211                 cs = private->chainstack[smp_processor_id()];
 212         else
 213                 cs = NULL;
 214         chaininfo = private->hook_entry[hook];
 215         nentries = private->hook_entry[hook]->nentries;
 216         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 217         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 218         /* base for chain jumps */
 219         base = private->entries;
 220         i = 0;
 221         while (i < nentries) {
 222                 if (ebt_basic_match(point, skb, in, out))
 223                         goto letscontinue;
 224
 225                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 226                         goto letscontinue;
 227                 if (acpar.hotdrop) {
 228                         read_unlock_bh(&table->lock);
 229                         return NF_DROP;
 230                 }
 231
 232                 /* increase counter */
 233                 (*(counter_base + i)).pcnt++;
 234                 (*(counter_base + i)).bcnt += skb->len;
 235
 236                 /* these should only watch: not modify, nor tell us
 237                    what to do with the packet */
 238                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 239
 240                 t = (struct ebt_entry_target *)
 241                    (((char *)point) + point->target_offset);
 242                 /* standard target */
 243                 if (!t->u.target->target)
 244                         verdict = ((struct ebt_standard_target *)t)->verdict;
 245                 else {
 246                         acpar.target   = t->u.target;
 247                         acpar.targinfo = t->data;
 248                         verdict = t->u.target->target(skb, &acpar);
 249                 }
 250                 if (verdict == EBT_ACCEPT) {
 251                         read_unlock_bh(&table->lock);
 252                         return NF_ACCEPT;
 253                 }
 254                 if (verdict == EBT_DROP) {
 255                         read_unlock_bh(&table->lock);
 256                         return NF_DROP;
 257                 }
 258                 if (verdict == EBT_RETURN) {
 259 letsreturn:
 260 #ifdef CONFIG_NETFILTER_DEBUG
 261                         if (sp == 0) {
 262                                 BUGPRINT("RETURN on base chain");
 263                                 /* act like this is EBT_CONTINUE */
 264                                 goto letscontinue;
 265                         }
 266 #endif
 267                         sp--;
 268                         /* put all the local variables right */
 269                         i = cs[sp].n;
 270                         chaininfo = cs[sp].chaininfo;
 271                         nentries = chaininfo->nentries;
 272                         point = cs[sp].e;
 273                         counter_base = cb_base +
 274                            chaininfo->counter_offset;
 275                         continue;
 276                 }
 277                 if (verdict == EBT_CONTINUE)
 278                         goto letscontinue;
 279 #ifdef CONFIG_NETFILTER_DEBUG
 280                 if (verdict < 0) {
 281                         BUGPRINT("bogus standard verdict\n");
 282                         read_unlock_bh(&table->lock);
 283                         return NF_DROP;
 284                 }
 285 #endif
 286                 /* jump to a udc */
 287                 cs[sp].n = i + 1;
 288                 cs[sp].chaininfo = chaininfo;
 289                 cs[sp].e = ebt_next_entry(point);
 290                 i = 0;
 291                 chaininfo = (struct ebt_entries *) (base + verdict);
 292 #ifdef CONFIG_NETFILTER_DEBUG
 293                 if (chaininfo->distinguisher) {
 294                         BUGPRINT("jump to non-chain\n");
 295                         read_unlock_bh(&table->lock);
 296                         return NF_DROP;
 297                 }
 298 #endif
 299                 nentries = chaininfo->nentries;
 300                 point = (struct ebt_entry *)chaininfo->data;
 301                 counter_base = cb_base + chaininfo->counter_offset;
 302                 sp++;
 303                 continue;
 304 letscontinue:
 305                 point = ebt_next_entry(point);
 306                 i++;
 307         }
 308
 309         /* I actually like this :) */
 310         if (chaininfo->policy == EBT_RETURN)
 311                 goto letsreturn;
 312         if (chaininfo->policy == EBT_ACCEPT) {
 313                 read_unlock_bh(&table->lock);
 314                 return NF_ACCEPT;
 315         }
 316         read_unlock_bh(&table->lock);
 317         return NF_DROP;
 318 }
 319
 320 /* If it succeeds, returns element and locks mutex */
 321 static inline void *
 322 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 323    struct mutex *mutex)
 324 {
 325         struct {
 326                 struct list_head list;
 327                 char name[EBT_FUNCTION_MAXNAMELEN];
 328         } *e;
 329
 330         *error = mutex_lock_interruptible(mutex);
 331         if (*error != 0)
 332                 return NULL;
 333
 334         list_for_each_entry(e, head, list) {
 335                 if (strcmp(e->name, name) == 0)
 336                         return e;
 337         }
 338         *error = -ENOENT;
 339         mutex_unlock(mutex);
 340         return NULL;
 341 }
 342
 343 static void *
 344 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 345    int *error, struct mutex *mutex)
 346 {
 347         return try_then_request_module(
 348                         find_inlist_lock_noload(head, name, error, mutex),
 349                         "%s%s", prefix, name);
 350 }
 351
 352 static inline struct ebt_table *
 353 find_table_lock(struct net *net, const char *name, int *error,
 354                 struct mutex *mutex)
 355 {
 356         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 357                                 "ebtable_", error, mutex);
 358 }
 359
 360 static inline int
 361 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 362                 unsigned int *cnt)
 363 {
 364         const struct ebt_entry *e = par->entryinfo;
 365         struct xt_match *match;
 366         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 367         int ret;
 368
 369         if (left < sizeof(struct ebt_entry_match) ||
 370             left - sizeof(struct ebt_entry_match) < m->match_size)
 371                 return -EINVAL;
 372
 373         match = xt_request_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 374         if (IS_ERR(match))
 375                 return PTR_ERR(match);
 376         m->u.match = match;
 377
 378         par->match     = match;
 379         par->matchinfo = m->data;
 380         ret = xt_check_match(par, m->match_size,
 381               e->ethproto, e->invflags & EBT_IPROTO);
 382         if (ret < 0) {
 383                 module_put(match->me);
 384                 return ret;
 385         }
 386
 387         (*cnt)++;
 388         return 0;
 389 }
 390
 391 static inline int
 392 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 393                   unsigned int *cnt)
 394 {
 395         const struct ebt_entry *e = par->entryinfo;
 396         struct xt_target *watcher;
 397         size_t left = ((char *)e + e->target_offset) - (char *)w;
 398         int ret;
 399
 400         if (left < sizeof(struct ebt_entry_watcher) ||
 401            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 402                 return -EINVAL;
 403
 404         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 405         if (IS_ERR(watcher))
 406                 return PTR_ERR(watcher);
 407         w->u.watcher = watcher;
 408
 409         par->target   = watcher;
 410         par->targinfo = w->data;
 411         ret = xt_check_target(par, w->watcher_size,
 412               e->ethproto, e->invflags & EBT_IPROTO);
 413         if (ret < 0) {
 414                 module_put(watcher->me);
 415                 return ret;
 416         }
 417
 418         (*cnt)++;
 419         return 0;
 420 }
 421
 422 static int ebt_verify_pointers(const struct ebt_replace *repl,
 423                                struct ebt_table_info *newinfo)
 424 {
 425         unsigned int limit = repl->entries_size;
 426         unsigned int valid_hooks = repl->valid_hooks;
 427         unsigned int offset = 0;
 428         int i;
 429
 430         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 431                 newinfo->hook_entry[i] = NULL;
 432
 433         newinfo->entries_size = repl->entries_size;
 434         newinfo->nentries = repl->nentries;
 435
 436         while (offset < limit) {
 437                 size_t left = limit - offset;
 438                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 439
 440                 if (left < sizeof(unsigned int))
 441                         break;
 442
 443                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 444                         if ((valid_hooks & (1 << i)) == 0)
 445                                 continue;
 446                         if ((char __user *)repl->hook_entry[i] ==
 447                              repl->entries + offset)
 448                                 break;
 449                 }
 450
 451                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 452                         if (e->bitmask != 0) {
 453                                 /* we make userspace set this right,
 454                                    so there is no misunderstanding */
 455                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 456                                          "in distinguisher\n");
 457                                 return -EINVAL;
 458                         }
 459                         if (i != NF_BR_NUMHOOKS)
 460                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 461                         if (left < sizeof(struct ebt_entries))
 462                                 break;
 463                         offset += sizeof(struct ebt_entries);
 464                 } else {
 465                         if (left < sizeof(struct ebt_entry))
 466                                 break;
 467                         if (left < e->next_offset)
 468                                 break;
 469                         if (e->next_offset < sizeof(struct ebt_entry))
 470                                 return -EINVAL;
 471                         offset += e->next_offset;
 472                 }
 473         }
 474         if (offset != limit) {
 475                 BUGPRINT("entries_size too small\n");
 476                 return -EINVAL;
 477         }
 478
 479         /* check if all valid hooks have a chain */
 480         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 481                 if (!newinfo->hook_entry[i] &&
 482                    (valid_hooks & (1 << i))) {
 483                         BUGPRINT("Valid hook without chain\n");
 484                         return -EINVAL;
 485                 }
 486         }
 487         return 0;
 488 }
 489
 490 /*
 491  * this one is very careful, as it is the first function
 492  * to parse the userspace data
 493  */
 494 static inline int
 495 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 496    const struct ebt_table_info *newinfo,
 497    unsigned int *n, unsigned int *cnt,
 498    unsigned int *totalcnt, unsigned int *udc_cnt)
 499 {
 500         int i;
 501
 502         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 503                 if ((void *)e == (void *)newinfo->hook_entry[i])
 504                         break;
 505         }
 506         /* beginning of a new chain
 507            if i == NF_BR_NUMHOOKS it must be a user defined chain */
 508         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 509                 /* this checks if the previous chain has as many entries
 510                    as it said it has */
 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 {
 554         struct ebt_chainstack cs;
 555         int from;
 556         unsigned int hookmask;
 557 };
 558
 559 /*
 560  * we need these positions to check that the jumps to a different part of the
 561  * entries is a jump to the beginning of a new chain.
 562  */
 563 static inline int
 564 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 565    unsigned int *n, struct ebt_cl_stack *udc)
 566 {
 567         int i;
 568
 569         /* we're only interested in chain starts */
 570         if (e->bitmask)
 571                 return 0;
 572         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 573                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 574                         break;
 575         }
 576         /* only care about udc */
 577         if (i != NF_BR_NUMHOOKS)
 578                 return 0;
 579
 580         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 581         /* these initialisations are depended on later in check_chainloops() */
 582         udc[*n].cs.n = 0;
 583         udc[*n].hookmask = 0;
 584
 585         (*n)++;
 586         return 0;
 587 }
 588
 589 static inline int
 590 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 591 {
 592         struct xt_mtdtor_param par;
 593
 594         if (i && (*i)-- == 0)
 595                 return 1;
 596
 597         par.net       = net;
 598         par.match     = m->u.match;
 599         par.matchinfo = m->data;
 600         par.family    = NFPROTO_BRIDGE;
 601         if (par.match->destroy != NULL)
 602                 par.match->destroy(&par);
 603         module_put(par.match->me);
 604         return 0;
 605 }
 606
 607 static inline int
 608 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 609 {
 610         struct xt_tgdtor_param par;
 611
 612         if (i && (*i)-- == 0)
 613                 return 1;
 614
 615         par.net      = net;
 616         par.target   = w->u.watcher;
 617         par.targinfo = w->data;
 618         par.family   = NFPROTO_BRIDGE;
 619         if (par.target->destroy != NULL)
 620                 par.target->destroy(&par);
 621         module_put(par.target->me);
 622         return 0;
 623 }
 624
 625 static inline int
 626 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 627 {
 628         struct xt_tgdtor_param par;
 629         struct ebt_entry_target *t;
 630
 631         if (e->bitmask == 0)
 632                 return 0;
 633         /* we're done */
 634         if (cnt && (*cnt)-- == 0)
 635                 return 1;
 636         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 637         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 638         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 639
 640         par.net      = net;
 641         par.target   = t->u.target;
 642         par.targinfo = t->data;
 643         par.family   = NFPROTO_BRIDGE;
 644         if (par.target->destroy != NULL)
 645                 par.target->destroy(&par);
 646         module_put(par.target->me);
 647         return 0;
 648 }
 649
 650 static inline int
 651 ebt_check_entry(struct ebt_entry *e, struct net *net,
 652    const struct ebt_table_info *newinfo,
 653    const char *name, unsigned int *cnt,
 654    struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 655 {
 656         struct ebt_entry_target *t;
 657         struct xt_target *target;
 658         unsigned int i, j, hook = 0, hookmask = 0;
 659         size_t gap;
 660         int ret;
 661         struct xt_mtchk_param mtpar;
 662         struct xt_tgchk_param tgpar;
 663
 664         /* don't mess with the struct ebt_entries */
 665         if (e->bitmask == 0)
 666                 return 0;
 667
 668         if (e->bitmask & ~EBT_F_MASK) {
 669                 BUGPRINT("Unknown flag for bitmask\n");
 670                 return -EINVAL;
 671         }
 672         if (e->invflags & ~EBT_INV_MASK) {
 673                 BUGPRINT("Unknown flag for inv bitmask\n");
 674                 return -EINVAL;
 675         }
 676         if ( (e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3) ) {
 677                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 678                 return -EINVAL;
 679         }
 680         /* what hook do we belong to? */
 681         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 682                 if (!newinfo->hook_entry[i])
 683                         continue;
 684                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 685                         hook = i;
 686                 else
 687                         break;
 688         }
 689         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 690            a base chain */
 691         if (i < NF_BR_NUMHOOKS)
 692                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 693         else {
 694                 for (i = 0; i < udc_cnt; i++)
 695                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 696                                 break;
 697                 if (i == 0)
 698                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 699                 else
 700                         hookmask = cl_s[i - 1].hookmask;
 701         }
 702         i = 0;
 703
 704         mtpar.net       = tgpar.net       = net;
 705         mtpar.table     = tgpar.table     = name;
 706         mtpar.entryinfo = tgpar.entryinfo = e;
 707         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 708         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 709         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 710         if (ret != 0)
 711                 goto cleanup_matches;
 712         j = 0;
 713         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 714         if (ret != 0)
 715                 goto cleanup_watchers;
 716         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 717         gap = e->next_offset - e->target_offset;
 718
 719         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 720         if (IS_ERR(target)) {
 721                 ret = PTR_ERR(target);
 722                 goto cleanup_watchers;
 723         }
 724
 725         t->u.target = target;
 726         if (t->u.target == &ebt_standard_target) {
 727                 if (gap < sizeof(struct ebt_standard_target)) {
 728                         BUGPRINT("Standard target size too big\n");
 729                         ret = -EFAULT;
 730                         goto cleanup_watchers;
 731                 }
 732                 if (((struct ebt_standard_target *)t)->verdict <
 733                    -NUM_STANDARD_TARGETS) {
 734                         BUGPRINT("Invalid standard target\n");
 735                         ret = -EFAULT;
 736                         goto cleanup_watchers;
 737                 }
 738         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 739                 module_put(t->u.target->me);
 740                 ret = -EFAULT;
 741                 goto cleanup_watchers;
 742         }
 743
 744         tgpar.target   = target;
 745         tgpar.targinfo = t->data;
 746         ret = xt_check_target(&tgpar, t->target_size,
 747               e->ethproto, e->invflags & EBT_IPROTO);
 748         if (ret < 0) {
 749                 module_put(target->me);
 750                 goto cleanup_watchers;
 751         }
 752         (*cnt)++;
 753         return 0;
 754 cleanup_watchers:
 755         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 756 cleanup_matches:
 757         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 758         return ret;
 759 }
 760
 761 /*
 762  * checks for loops and sets the hook mask for udc
 763  * the hook mask for udc tells us from which base chains the udc can be
 764  * accessed. This mask is a parameter to the check() functions of the extensions
 765  */
 766 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 767    unsigned int udc_cnt, unsigned int hooknr, char *base)
 768 {
 769         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 770         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 771         const struct ebt_entry_target *t;
 772
 773         while (pos < nentries || chain_nr != -1) {
 774                 /* end of udc, go back one 'recursion' step */
 775                 if (pos == nentries) {
 776                         /* put back values of the time when this chain was called */
 777                         e = cl_s[chain_nr].cs.e;
 778                         if (cl_s[chain_nr].from != -1)
 779                                 nentries =
 780                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 781                         else
 782                                 nentries = chain->nentries;
 783                         pos = cl_s[chain_nr].cs.n;
 784                         /* make sure we won't see a loop that isn't one */
 785                         cl_s[chain_nr].cs.n = 0;
 786                         chain_nr = cl_s[chain_nr].from;
 787                         if (pos == nentries)
 788                                 continue;
 789                 }
 790                 t = (struct ebt_entry_target *)
 791                    (((char *)e) + e->target_offset);
 792                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 793                         goto letscontinue;
 794                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 795                    e->next_offset) {
 796                         BUGPRINT("Standard target size too big\n");
 797                         return -1;
 798                 }
 799                 verdict = ((struct ebt_standard_target *)t)->verdict;
 800                 if (verdict >= 0) { /* jump to another chain */
 801                         struct ebt_entries *hlp2 =
 802                            (struct ebt_entries *)(base + verdict);
 803                         for (i = 0; i < udc_cnt; i++)
 804                                 if (hlp2 == cl_s[i].cs.chaininfo)
 805                                         break;
 806                         /* bad destination or loop */
 807                         if (i == udc_cnt) {
 808                                 BUGPRINT("bad destination\n");
 809                                 return -1;
 810                         }
 811                         if (cl_s[i].cs.n) {
 812                                 BUGPRINT("loop\n");
 813                                 return -1;
 814                         }
 815                         if (cl_s[i].hookmask & (1 << hooknr))
 816                                 goto letscontinue;
 817                         /* this can't be 0, so the loop test is correct */
 818                         cl_s[i].cs.n = pos + 1;
 819                         pos = 0;
 820                         cl_s[i].cs.e = ebt_next_entry(e);
 821                         e = (struct ebt_entry *)(hlp2->data);
 822                         nentries = hlp2->nentries;
 823                         cl_s[i].from = chain_nr;
 824                         chain_nr = i;
 825                         /* this udc is accessible from the base chain for hooknr */
 826                         cl_s[i].hookmask |= (1 << hooknr);
 827                         continue;
 828                 }
 829 letscontinue:
 830                 e = ebt_next_entry(e);
 831                 pos++;
 832         }
 833         return 0;
 834 }
 835
 836 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 837 static int translate_table(struct net *net, const char *name,
 838                            struct ebt_table_info *newinfo)
 839 {
 840         unsigned int i, j, k, udc_cnt;
 841         int ret;
 842         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 843
 844         i = 0;
 845         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 846                 i++;
 847         if (i == NF_BR_NUMHOOKS) {
 848                 BUGPRINT("No valid hooks specified\n");
 849                 return -EINVAL;
 850         }
 851         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 852                 BUGPRINT("Chains don't start at beginning\n");
 853                 return -EINVAL;
 854         }
 855         /* make sure chains are ordered after each other in same order
 856            as their corresponding hooks */
 857         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 858                 if (!newinfo->hook_entry[j])
 859                         continue;
 860                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 861                         BUGPRINT("Hook order must be followed\n");
 862                         return -EINVAL;
 863                 }
 864                 i = j;
 865         }
 866
 867         /* do some early checkings and initialize some things */
 868         i = 0; /* holds the expected nr. of entries for the chain */
 869         j = 0; /* holds the up to now counted entries for the chain */
 870         k = 0; /* holds the total nr. of entries, should equal
 871                   newinfo->nentries afterwards */
 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         if (udc_cnt) {
 893                 /* this will get free'd in do_replace()/ebt_register_table()
 894                    if an error occurs */
 895                 newinfo->chainstack =
 896                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 897                 if (!newinfo->chainstack)
 898                         return -ENOMEM;
 899                 for_each_possible_cpu(i) {
 900                         newinfo->chainstack[i] =
 901                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 902                         if (!newinfo->chainstack[i]) {
 903                                 while (i)
 904                                         vfree(newinfo->chainstack[--i]);
 905                                 vfree(newinfo->chainstack);
 906                                 newinfo->chainstack = NULL;
 907                                 return -ENOMEM;
 908                         }
 909                 }
 910
 911                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 912                 if (!cl_s)
 913                         return -ENOMEM;
 914                 i = 0; /* the i'th udc */
 915                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 916                    ebt_get_udc_positions, newinfo, &i, cl_s);
 917                 /* sanity check */
 918                 if (i != udc_cnt) {
 919                         BUGPRINT("i != udc_cnt\n");
 920                         vfree(cl_s);
 921                         return -EFAULT;
 922                 }
 923         }
 924
 925         /* Check for loops */
 926         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 927                 if (newinfo->hook_entry[i])
 928                         if (check_chainloops(newinfo->hook_entry[i],
 929                            cl_s, udc_cnt, i, newinfo->entries)) {
 930                                 vfree(cl_s);
 931                                 return -EINVAL;
 932                         }
 933
 934         /* we now know the following (along with E=mc²):
 935            - the nr of entries in each chain is right
 936            - the size of the allocated space is right
 937            - all valid hooks have a corresponding chain
 938            - there are no loops
 939            - wrong data can still be on the level of a single entry
 940            - could be there are jumps to places that are not the
 941              beginning of a chain. This can only occur in chains that
 942              are not accessible from any base chains, so we don't care. */
 943
 944         /* used to know what we need to clean up if something goes wrong */
 945         i = 0;
 946         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 947            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 948         if (ret != 0) {
 949                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 950                                   ebt_cleanup_entry, net, &i);
 951         }
 952         vfree(cl_s);
 953         return ret;
 954 }
 955
 956 /* called under write_lock */
 957 static void get_counters(const struct ebt_counter *oldcounters,
 958    struct ebt_counter *counters, unsigned int nentries)
 959 {
 960         int i, cpu;
 961         struct ebt_counter *counter_base;
 962
 963         /* counters of cpu 0 */
 964         memcpy(counters, oldcounters,
 965                sizeof(struct ebt_counter) * nentries);
 966
 967         /* add other counters to those of cpu 0 */
 968         for_each_possible_cpu(cpu) {
 969                 if (cpu == 0)
 970                         continue;
 971                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 972                 for (i = 0; i < nentries; i++) {
 973                         counters[i].pcnt += counter_base[i].pcnt;
 974                         counters[i].bcnt += counter_base[i].bcnt;
 975                 }
 976         }
 977 }
 978
 979 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 980                               struct ebt_table_info *newinfo)
 981 {
 982         int ret, i;
 983         struct ebt_counter *counterstmp = NULL;
 984         /* used to be able to unlock earlier */
 985         struct ebt_table_info *table;
 986         struct ebt_table *t;
 987
 988         /* the user wants counters back
 989            the check on the size is done later, when we have the lock */
 990         if (repl->num_counters) {
 991                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 992                 counterstmp = vmalloc(size);
 993                 if (!counterstmp)
 994                         return -ENOMEM;
 995         }
 996
 997         newinfo->chainstack = NULL;
 998         ret = ebt_verify_pointers(repl, newinfo);
 999         if (ret != 0)
1000                 goto free_counterstmp;
1001
1002         ret = translate_table(net, repl->name, newinfo);
1003
1004         if (ret != 0)
1005                 goto free_counterstmp;
1006
1007         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1008         if (!t) {
1009                 ret = -ENOENT;
1010                 goto free_iterate;
1011         }
1012
1013         /* the table doesn't like it */
1014         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1015                 goto free_unlock;
1016
1017         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1018                 BUGPRINT("Wrong nr. of counters requested\n");
1019                 ret = -EINVAL;
1020                 goto free_unlock;
1021         }
1022
1023         /* we have the mutex lock, so no danger in reading this pointer */
1024         table = t->private;
1025         /* make sure the table can only be rmmod'ed if it contains no rules */
1026         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1027                 ret = -ENOENT;
1028                 goto free_unlock;
1029         } else if (table->nentries && !newinfo->nentries)
1030                 module_put(t->me);
1031         /* we need an atomic snapshot of the counters */
1032         write_lock_bh(&t->lock);
1033         if (repl->num_counters)
1034                 get_counters(t->private->counters, counterstmp,
1035                    t->private->nentries);
1036
1037         t->private = newinfo;
1038         write_unlock_bh(&t->lock);
1039         mutex_unlock(&ebt_mutex);
1040         /* so, a user can change the chains while having messed up her counter
1041            allocation. Only reason why this is done is because this way the lock
1042            is held only once, while this doesn't bring the kernel into a
1043            dangerous state. */
1044         if (repl->num_counters &&
1045            copy_to_user(repl->counters, counterstmp,
1046            repl->num_counters * sizeof(struct ebt_counter))) {
1047                 ret = -EFAULT;
1048         }
1049         else
1050                 ret = 0;
1051
1052         /* decrease module count and free resources */
1053         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1054                           ebt_cleanup_entry, net, NULL);
1055
1056         vfree(table->entries);
1057         if (table->chainstack) {
1058                 for_each_possible_cpu(i)
1059                         vfree(table->chainstack[i]);
1060                 vfree(table->chainstack);
1061         }
1062         vfree(table);
1063
1064         vfree(counterstmp);
1065         return ret;
1066
1067 free_unlock:
1068         mutex_unlock(&ebt_mutex);
1069 free_iterate:
1070         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1071                           ebt_cleanup_entry, net, NULL);
1072 free_counterstmp:
1073         vfree(counterstmp);
1074         /* can be initialized in translate_table() */
1075         if (newinfo->chainstack) {
1076                 for_each_possible_cpu(i)
1077                         vfree(newinfo->chainstack[i]);
1078                 vfree(newinfo->chainstack);
1079         }
1080         return ret;
1081 }
1082
1083 /* replace the table */
1084 static int do_replace(struct net *net, const void __user *user,
1085                       unsigned int len)
1086 {
1087         int ret, countersize;
1088         struct ebt_table_info *newinfo;
1089         struct ebt_replace tmp;
1090
1091         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1092                 return -EFAULT;
1093
1094         if (len != sizeof(tmp) + tmp.entries_size) {
1095                 BUGPRINT("Wrong len argument\n");
1096                 return -EINVAL;
1097         }
1098
1099         if (tmp.entries_size == 0) {
1100                 BUGPRINT("Entries_size never zero\n");
1101                 return -EINVAL;
1102         }
1103         /* overflow check */
1104         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1105                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1106                 return -ENOMEM;
1107         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1108                 return -ENOMEM;
1109
1110         tmp.name[sizeof(tmp.name) - 1] = 0;
1111
1112         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1113         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1114         if (!newinfo)
1115                 return -ENOMEM;
1116
1117         if (countersize)
1118                 memset(newinfo->counters, 0, countersize);
1119
1120         newinfo->entries = vmalloc(tmp.entries_size);
1121         if (!newinfo->entries) {
1122                 ret = -ENOMEM;
1123                 goto free_newinfo;
1124         }
1125         if (copy_from_user(
1126            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1127                 BUGPRINT("Couldn't copy entries from userspace\n");
1128                 ret = -EFAULT;
1129                 goto free_entries;
1130         }
1131
1132         ret = do_replace_finish(net, &tmp, newinfo);
1133         if (ret == 0)
1134                 return ret;
1135 free_entries:
1136         vfree(newinfo->entries);
1137 free_newinfo:
1138         vfree(newinfo);
1139         return ret;
1140 }
1141
1142 struct ebt_table *
1143 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1144 {
1145         struct ebt_table_info *newinfo;
1146         struct ebt_table *t, *table;
1147         struct ebt_replace_kernel *repl;
1148         int ret, i, countersize;
1149         void *p;
1150
1151         if (input_table == NULL || (repl = input_table->table) == NULL ||
1152             repl->entries == NULL || repl->entries_size == 0 ||
1153             repl->counters != NULL || input_table->private != NULL) {
1154                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1155                 return ERR_PTR(-EINVAL);
1156         }
1157
1158         /* Don't add one table to multiple lists. */
1159         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1160         if (!table) {
1161                 ret = -ENOMEM;
1162                 goto out;
1163         }
1164
1165         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1166         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1167         ret = -ENOMEM;
1168         if (!newinfo)
1169                 goto free_table;
1170
1171         p = vmalloc(repl->entries_size);
1172         if (!p)
1173                 goto free_newinfo;
1174
1175         memcpy(p, repl->entries, repl->entries_size);
1176         newinfo->entries = p;
1177
1178         newinfo->entries_size = repl->entries_size;
1179         newinfo->nentries = repl->nentries;
1180
1181         if (countersize)
1182                 memset(newinfo->counters, 0, countersize);
1183
1184         /* fill in newinfo and parse the entries */
1185         newinfo->chainstack = NULL;
1186         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1187                 if ((repl->valid_hooks & (1 << i)) == 0)
1188                         newinfo->hook_entry[i] = NULL;
1189                 else
1190                         newinfo->hook_entry[i] = p +
1191                                 ((char *)repl->hook_entry[i] - repl->entries);
1192         }
1193         ret = translate_table(net, repl->name, newinfo);
1194         if (ret != 0) {
1195                 BUGPRINT("Translate_table failed\n");
1196                 goto free_chainstack;
1197         }
1198
1199         if (table->check && table->check(newinfo, table->valid_hooks)) {
1200                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1201                 ret = -EINVAL;
1202                 goto free_chainstack;
1203         }
1204
1205         table->private = newinfo;
1206         rwlock_init(&table->lock);
1207         ret = mutex_lock_interruptible(&ebt_mutex);
1208         if (ret != 0)
1209                 goto free_chainstack;
1210
1211         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1212                 if (strcmp(t->name, table->name) == 0) {
1213                         ret = -EEXIST;
1214                         BUGPRINT("Table name already exists\n");
1215                         goto free_unlock;
1216                 }
1217         }
1218
1219         /* Hold a reference count if the chains aren't empty */
1220         if (newinfo->nentries && !try_module_get(table->me)) {
1221                 ret = -ENOENT;
1222                 goto free_unlock;
1223         }
1224         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1225         mutex_unlock(&ebt_mutex);
1226         return table;
1227 free_unlock:
1228         mutex_unlock(&ebt_mutex);
1229 free_chainstack:
1230         if (newinfo->chainstack) {
1231                 for_each_possible_cpu(i)
1232                         vfree(newinfo->chainstack[i]);
1233                 vfree(newinfo->chainstack);
1234         }
1235         vfree(newinfo->entries);
1236 free_newinfo:
1237         vfree(newinfo);
1238 free_table:
1239         kfree(table);
1240 out:
1241         return ERR_PTR(ret);
1242 }
1243
1244 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1245 {
1246         int i;
1247
1248         if (!table) {
1249                 BUGPRINT("Request to unregister NULL table!!!\n");
1250                 return;
1251         }
1252         mutex_lock(&ebt_mutex);
1253         list_del(&table->list);
1254         mutex_unlock(&ebt_mutex);
1255         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1256                           ebt_cleanup_entry, net, NULL);
1257         if (table->private->nentries)
1258                 module_put(table->me);
1259         vfree(table->private->entries);
1260         if (table->private->chainstack) {
1261                 for_each_possible_cpu(i)
1262                         vfree(table->private->chainstack[i]);
1263                 vfree(table->private->chainstack);
1264         }
1265         vfree(table->private);
1266         kfree(table);
1267 }
1268
1269 /* userspace just supplied us with counters */
1270 static int do_update_counters(struct net *net, const char *name,
1271                                 struct ebt_counter __user *counters,
1272                                 unsigned int num_counters,
1273                                 const void __user *user, unsigned int len)
1274 {
1275         int i, ret;
1276         struct ebt_counter *tmp;
1277         struct ebt_table *t;
1278
1279         if (num_counters == 0)
1280                 return -EINVAL;
1281
1282         tmp = vmalloc(num_counters * sizeof(*tmp));
1283         if (!tmp)
1284                 return -ENOMEM;
1285
1286         t = find_table_lock(net, name, &ret, &ebt_mutex);
1287         if (!t)
1288                 goto free_tmp;
1289
1290         if (num_counters != t->private->nentries) {
1291                 BUGPRINT("Wrong nr of counters\n");
1292                 ret = -EINVAL;
1293                 goto unlock_mutex;
1294         }
1295
1296         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1297                 ret = -EFAULT;
1298                 goto unlock_mutex;
1299         }
1300
1301         /* we want an atomic add of the counters */
1302         write_lock_bh(&t->lock);
1303
1304         /* we add to the counters of the first cpu */
1305         for (i = 0; i < num_counters; i++) {
1306                 t->private->counters[i].pcnt += tmp[i].pcnt;
1307                 t->private->counters[i].bcnt += tmp[i].bcnt;
1308         }
1309
1310         write_unlock_bh(&t->lock);
1311         ret = 0;
1312 unlock_mutex:
1313         mutex_unlock(&ebt_mutex);
1314 free_tmp:
1315         vfree(tmp);
1316         return ret;
1317 }
1318
1319 static int update_counters(struct net *net, const void __user *user,
1320                             unsigned int len)
1321 {
1322         struct ebt_replace hlp;
1323
1324         if (copy_from_user(&hlp, user, sizeof(hlp)))
1325                 return -EFAULT;
1326
1327         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1328                 return -EINVAL;
1329
1330         return do_update_counters(net, hlp.name, hlp.counters,
1331                                 hlp.num_counters, user, len);
1332 }
1333
1334 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1335     const char *base, char __user *ubase)
1336 {
1337         char __user *hlp = ubase + ((char *)m - base);
1338         if (copy_to_user(hlp, m->u.match->name, EBT_FUNCTION_MAXNAMELEN))
1339                 return -EFAULT;
1340         return 0;
1341 }
1342
1343 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1344     const char *base, char __user *ubase)
1345 {
1346         char __user *hlp = ubase + ((char *)w - base);
1347         if (copy_to_user(hlp , w->u.watcher->name, EBT_FUNCTION_MAXNAMELEN))
1348                 return -EFAULT;
1349         return 0;
1350 }
1351
1352 static inline int
1353 ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase)
1354 {
1355         int ret;
1356         char __user *hlp;
1357         const struct ebt_entry_target *t;
1358
1359         if (e->bitmask == 0)
1360                 return 0;
1361
1362         hlp = ubase + (((char *)e + e->target_offset) - base);
1363         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1364
1365         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1366         if (ret != 0)
1367                 return ret;
1368         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1369         if (ret != 0)
1370                 return ret;
1371         if (copy_to_user(hlp, t->u.target->name, EBT_FUNCTION_MAXNAMELEN))
1372                 return -EFAULT;
1373         return 0;
1374 }
1375
1376 static int copy_counters_to_user(struct ebt_table *t,
1377                                   const struct ebt_counter *oldcounters,
1378                                   void __user *user, unsigned int num_counters,
1379                                   unsigned int nentries)
1380 {
1381         struct ebt_counter *counterstmp;
1382         int ret = 0;
1383
1384         /* userspace might not need the counters */
1385         if (num_counters == 0)
1386                 return 0;
1387
1388         if (num_counters != nentries) {
1389                 BUGPRINT("Num_counters wrong\n");
1390                 return -EINVAL;
1391         }
1392
1393         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1394         if (!counterstmp)
1395                 return -ENOMEM;
1396
1397         write_lock_bh(&t->lock);
1398         get_counters(oldcounters, counterstmp, nentries);
1399         write_unlock_bh(&t->lock);
1400
1401         if (copy_to_user(user, counterstmp,
1402            nentries * sizeof(struct ebt_counter)))
1403                 ret = -EFAULT;
1404         vfree(counterstmp);
1405         return ret;
1406 }
1407
1408 /* called with ebt_mutex locked */
1409 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1410     const int *len, int cmd)
1411 {
1412         struct ebt_replace tmp;
1413         const struct ebt_counter *oldcounters;
1414         unsigned int entries_size, nentries;
1415         int ret;
1416         char *entries;
1417
1418         if (cmd == EBT_SO_GET_ENTRIES) {
1419                 entries_size = t->private->entries_size;
1420                 nentries = t->private->nentries;
1421                 entries = t->private->entries;
1422                 oldcounters = t->private->counters;
1423         } else {
1424                 entries_size = t->table->entries_size;
1425                 nentries = t->table->nentries;
1426                 entries = t->table->entries;
1427                 oldcounters = t->table->counters;
1428         }
1429
1430         if (copy_from_user(&tmp, user, sizeof(tmp)))
1431                 return -EFAULT;
1432
1433         if (*len != sizeof(struct ebt_replace) + entries_size +
1434            (tmp.num_counters? nentries * sizeof(struct ebt_counter): 0))
1435                 return -EINVAL;
1436
1437         if (tmp.nentries != nentries) {
1438                 BUGPRINT("Nentries wrong\n");
1439                 return -EINVAL;
1440         }
1441
1442         if (tmp.entries_size != entries_size) {
1443                 BUGPRINT("Wrong size\n");
1444                 return -EINVAL;
1445         }
1446
1447         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1448                                         tmp.num_counters, nentries);
1449         if (ret)
1450                 return ret;
1451
1452         if (copy_to_user(tmp.entries, entries, entries_size)) {
1453                 BUGPRINT("Couldn't copy entries to userspace\n");
1454                 return -EFAULT;
1455         }
1456         /* set the match/watcher/target names right */
1457         return EBT_ENTRY_ITERATE(entries, entries_size,
1458            ebt_make_names, entries, tmp.entries);
1459 }
1460
1461 static int do_ebt_set_ctl(struct sock *sk,
1462         int cmd, void __user *user, unsigned int len)
1463 {
1464         int ret;
1465
1466         if (!capable(CAP_NET_ADMIN))
1467                 return -EPERM;
1468
1469         switch(cmd) {
1470         case EBT_SO_SET_ENTRIES:
1471                 ret = do_replace(sock_net(sk), user, len);
1472                 break;
1473         case EBT_SO_SET_COUNTERS:
1474                 ret = update_counters(sock_net(sk), user, len);
1475                 break;
1476         default:
1477                 ret = -EINVAL;
1478         }
1479         return ret;
1480 }
1481
1482 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1483 {
1484         int ret;
1485         struct ebt_replace tmp;
1486         struct ebt_table *t;
1487
1488         if (!capable(CAP_NET_ADMIN))
1489                 return -EPERM;
1490
1491         if (copy_from_user(&tmp, user, sizeof(tmp)))
1492                 return -EFAULT;
1493
1494         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
1495         if (!t)
1496                 return ret;
1497
1498         switch(cmd) {
1499         case EBT_SO_GET_INFO:
1500         case EBT_SO_GET_INIT_INFO:
1501                 if (*len != sizeof(struct ebt_replace)){
1502                         ret = -EINVAL;
1503                         mutex_unlock(&ebt_mutex);
1504                         break;
1505                 }
1506                 if (cmd == EBT_SO_GET_INFO) {
1507                         tmp.nentries = t->private->nentries;
1508                         tmp.entries_size = t->private->entries_size;
1509                         tmp.valid_hooks = t->valid_hooks;
1510                 } else {
1511                         tmp.nentries = t->table->nentries;
1512                         tmp.entries_size = t->table->entries_size;
1513                         tmp.valid_hooks = t->table->valid_hooks;
1514                 }
1515                 mutex_unlock(&ebt_mutex);
1516                 if (copy_to_user(user, &tmp, *len) != 0){
1517                         BUGPRINT("c2u Didn't work\n");
1518                         ret = -EFAULT;
1519                         break;
1520                 }
1521                 ret = 0;
1522                 break;
1523
1524         case EBT_SO_GET_ENTRIES:
1525         case EBT_SO_GET_INIT_ENTRIES:
1526                 ret = copy_everything_to_user(t, user, len, cmd);
1527                 mutex_unlock(&ebt_mutex);
1528                 break;
1529
1530         default:
1531                 mutex_unlock(&ebt_mutex);
1532                 ret = -EINVAL;
1533         }
1534
1535         return ret;
1536 }
1537
1538 #ifdef CONFIG_COMPAT
1539 /* 32 bit-userspace compatibility definitions. */
1540 struct compat_ebt_replace {
1541         char name[EBT_TABLE_MAXNAMELEN];
1542         compat_uint_t valid_hooks;
1543         compat_uint_t nentries;
1544         compat_uint_t entries_size;
1545         /* start of the chains */
1546         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1547         /* nr of counters userspace expects back */
1548         compat_uint_t num_counters;
1549         /* where the kernel will put the old counters. */
1550         compat_uptr_t counters;
1551         compat_uptr_t entries;
1552 };
1553
1554 /* struct ebt_entry_match, _target and _watcher have same layout */
1555 struct compat_ebt_entry_mwt {
1556         union {
1557                 char name[EBT_FUNCTION_MAXNAMELEN];
1558                 compat_uptr_t ptr;
1559         } u;
1560         compat_uint_t match_size;
1561         compat_uint_t data[0];
1562 };
1563
1564 /* account for possible padding between match_size and ->data */
1565 static int ebt_compat_entry_padsize(void)
1566 {
1567         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1568                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1569         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1570                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1571 }
1572
1573 static int ebt_compat_match_offset(const struct xt_match *match,
1574                                    unsigned int userlen)
1575 {
1576         /*
1577          * ebt_among needs special handling. The kernel .matchsize is
1578          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1579          * value is expected.
1580          * Example: userspace sends 4500, ebt_among.c wants 4504.
1581          */
1582         if (unlikely(match->matchsize == -1))
1583                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1584         return xt_compat_match_offset(match);
1585 }
1586
1587 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1588                                 unsigned int *size)
1589 {
1590         const struct xt_match *match = m->u.match;
1591         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1592         int off = ebt_compat_match_offset(match, m->match_size);
1593         compat_uint_t msize = m->match_size - off;
1594
1595         BUG_ON(off >= m->match_size);
1596
1597         if (copy_to_user(cm->u.name, match->name,
1598             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1599                 return -EFAULT;
1600
1601         if (match->compat_to_user) {
1602                 if (match->compat_to_user(cm->data, m->data))
1603                         return -EFAULT;
1604         } else if (copy_to_user(cm->data, m->data, msize))
1605                         return -EFAULT;
1606
1607         *size -= ebt_compat_entry_padsize() + off;
1608         *dstptr = cm->data;
1609         *dstptr += msize;
1610         return 0;
1611 }
1612
1613 static int compat_target_to_user(struct ebt_entry_target *t,
1614                                  void __user **dstptr,
1615                                  unsigned int *size)
1616 {
1617         const struct xt_target *target = t->u.target;
1618         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1619         int off = xt_compat_target_offset(target);
1620         compat_uint_t tsize = t->target_size - off;
1621
1622         BUG_ON(off >= t->target_size);
1623
1624         if (copy_to_user(cm->u.name, target->name,
1625             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1626                 return -EFAULT;
1627
1628         if (target->compat_to_user) {
1629                 if (target->compat_to_user(cm->data, t->data))
1630                         return -EFAULT;
1631         } else if (copy_to_user(cm->data, t->data, tsize))
1632                 return -EFAULT;
1633
1634         *size -= ebt_compat_entry_padsize() + off;
1635         *dstptr = cm->data;
1636         *dstptr += tsize;
1637         return 0;
1638 }
1639
1640 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1641                                   void __user **dstptr,
1642                                   unsigned int *size)
1643 {
1644         return compat_target_to_user((struct ebt_entry_target *)w,
1645                                                         dstptr, size);
1646 }
1647
1648 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1649                                 unsigned int *size)
1650 {
1651         struct ebt_entry_target *t;
1652         struct ebt_entry __user *ce;
1653         u32 watchers_offset, target_offset, next_offset;
1654         compat_uint_t origsize;
1655         int ret;
1656
1657         if (e->bitmask == 0) {
1658                 if (*size < sizeof(struct ebt_entries))
1659                         return -EINVAL;
1660                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1661                         return -EFAULT;
1662
1663                 *dstptr += sizeof(struct ebt_entries);
1664                 *size -= sizeof(struct ebt_entries);
1665                 return 0;
1666         }
1667
1668         if (*size < sizeof(*ce))
1669                 return -EINVAL;
1670
1671         ce = (struct ebt_entry __user *)*dstptr;
1672         if (copy_to_user(ce, e, sizeof(*ce)))
1673                 return -EFAULT;
1674
1675         origsize = *size;
1676         *dstptr += sizeof(*ce);
1677
1678         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1679         if (ret)
1680                 return ret;
1681         watchers_offset = e->watchers_offset - (origsize - *size);
1682
1683         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1684         if (ret)
1685                 return ret;
1686         target_offset = e->target_offset - (origsize - *size);
1687
1688         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1689
1690         ret = compat_target_to_user(t, dstptr, size);
1691         if (ret)
1692                 return ret;
1693         next_offset = e->next_offset - (origsize - *size);
1694
1695         if (put_user(watchers_offset, &ce->watchers_offset) ||
1696             put_user(target_offset, &ce->target_offset) ||
1697             put_user(next_offset, &ce->next_offset))
1698                 return -EFAULT;
1699
1700         *size -= sizeof(*ce);
1701         return 0;
1702 }
1703
1704 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1705 {
1706         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1707         *off += ebt_compat_entry_padsize();
1708         return 0;
1709 }
1710
1711 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1712 {
1713         *off += xt_compat_target_offset(w->u.watcher);
1714         *off += ebt_compat_entry_padsize();
1715         return 0;
1716 }
1717
1718 static int compat_calc_entry(const struct ebt_entry *e,
1719                              const struct ebt_table_info *info,
1720                              const void *base,
1721                              struct compat_ebt_replace *newinfo)
1722 {
1723         const struct ebt_entry_target *t;
1724         unsigned int entry_offset;
1725         int off, ret, i;
1726
1727         if (e->bitmask == 0)
1728                 return 0;
1729
1730         off = 0;
1731         entry_offset = (void *)e - base;
1732
1733         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1734         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1735
1736         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1737
1738         off += xt_compat_target_offset(t->u.target);
1739         off += ebt_compat_entry_padsize();
1740
1741         newinfo->entries_size -= off;
1742
1743         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1744         if (ret)
1745                 return ret;
1746
1747         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1748                 const void *hookptr = info->hook_entry[i];
1749                 if (info->hook_entry[i] &&
1750                     (e < (struct ebt_entry *)(base - hookptr))) {
1751                         newinfo->hook_entry[i] -= off;
1752                         pr_debug("0x%08X -> 0x%08X\n",
1753                                         newinfo->hook_entry[i] + off,
1754                                         newinfo->hook_entry[i]);
1755                 }
1756         }
1757
1758         return 0;
1759 }
1760
1761
1762 static int compat_table_info(const struct ebt_table_info *info,
1763                              struct compat_ebt_replace *newinfo)
1764 {
1765         unsigned int size = info->entries_size;
1766         const void *entries = info->entries;
1767
1768         newinfo->entries_size = size;
1769
1770         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1771         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1772                                                         entries, newinfo);
1773 }
1774
1775 static int compat_copy_everything_to_user(struct ebt_table *t,
1776                                           void __user *user, int *len, int cmd)
1777 {
1778         struct compat_ebt_replace repl, tmp;
1779         struct ebt_counter *oldcounters;
1780         struct ebt_table_info tinfo;
1781         int ret;
1782         void __user *pos;
1783
1784         memset(&tinfo, 0, sizeof(tinfo));
1785
1786         if (cmd == EBT_SO_GET_ENTRIES) {
1787                 tinfo.entries_size = t->private->entries_size;
1788                 tinfo.nentries = t->private->nentries;
1789                 tinfo.entries = t->private->entries;
1790                 oldcounters = t->private->counters;
1791         } else {
1792                 tinfo.entries_size = t->table->entries_size;
1793                 tinfo.nentries = t->table->nentries;
1794                 tinfo.entries = t->table->entries;
1795                 oldcounters = t->table->counters;
1796         }
1797
1798         if (copy_from_user(&tmp, user, sizeof(tmp)))
1799                 return -EFAULT;
1800
1801         if (tmp.nentries != tinfo.nentries ||
1802            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1803                 return -EINVAL;
1804
1805         memcpy(&repl, &tmp, sizeof(repl));
1806         if (cmd == EBT_SO_GET_ENTRIES)
1807                 ret = compat_table_info(t->private, &repl);
1808         else
1809                 ret = compat_table_info(&tinfo, &repl);
1810         if (ret)
1811                 return ret;
1812
1813         if (*len != sizeof(tmp) + repl.entries_size +
1814            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1815                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1816                                 *len, tinfo.entries_size, repl.entries_size);
1817                 return -EINVAL;
1818         }
1819
1820         /* userspace might not need the counters */
1821         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1822                                         tmp.num_counters, tinfo.nentries);
1823         if (ret)
1824                 return ret;
1825
1826         pos = compat_ptr(tmp.entries);
1827         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1828                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1829 }
1830
1831 struct ebt_entries_buf_state {
1832         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1833         u32 buf_kern_len;       /* total size of kernel buffer */
1834         u32 buf_kern_offset;    /* amount of data copied so far */
1835         u32 buf_user_offset;    /* read position in userspace buffer */
1836 };
1837
1838 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1839 {
1840         state->buf_kern_offset += sz;
1841         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1842 }
1843
1844 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1845                        void *data, unsigned int sz)
1846 {
1847         if (state->buf_kern_start == NULL)
1848                 goto count_only;
1849
1850         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1851
1852         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1853
1854  count_only:
1855         state->buf_user_offset += sz;
1856         return ebt_buf_count(state, sz);
1857 }
1858
1859 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1860 {
1861         char *b = state->buf_kern_start;
1862
1863         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1864
1865         if (b != NULL && sz > 0)
1866                 memset(b + state->buf_kern_offset, 0, sz);
1867         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1868         return ebt_buf_count(state, sz);
1869 }
1870
1871 enum compat_mwt {
1872         EBT_COMPAT_MATCH,
1873         EBT_COMPAT_WATCHER,
1874         EBT_COMPAT_TARGET,
1875 };
1876
1877 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1878                                 enum compat_mwt compat_mwt,
1879                                 struct ebt_entries_buf_state *state,
1880                                 const unsigned char *base)
1881 {
1882         char name[EBT_FUNCTION_MAXNAMELEN];
1883         struct xt_match *match;
1884         struct xt_target *wt;
1885         void *dst = NULL;
1886         int off, pad = 0;
1887         unsigned int size_kern, match_size = mwt->match_size;
1888
1889         strlcpy(name, mwt->u.name, sizeof(name));
1890
1891         if (state->buf_kern_start)
1892                 dst = state->buf_kern_start + state->buf_kern_offset;
1893
1894         switch (compat_mwt) {
1895         case EBT_COMPAT_MATCH:
1896                 match = try_then_request_module(xt_find_match(NFPROTO_BRIDGE,
1897                                                 name, 0), "ebt_%s", name);
1898                 if (match == NULL)
1899                         return -ENOENT;
1900                 if (IS_ERR(match))
1901                         return PTR_ERR(match);
1902
1903                 off = ebt_compat_match_offset(match, match_size);
1904                 if (dst) {
1905                         if (match->compat_from_user)
1906                                 match->compat_from_user(dst, mwt->data);
1907                         else
1908                                 memcpy(dst, mwt->data, match_size);
1909                 }
1910
1911                 size_kern = match->matchsize;
1912                 if (unlikely(size_kern == -1))
1913                         size_kern = match_size;
1914                 module_put(match->me);
1915                 break;
1916         case EBT_COMPAT_WATCHER: /* fallthrough */
1917         case EBT_COMPAT_TARGET:
1918                 wt = try_then_request_module(xt_find_target(NFPROTO_BRIDGE,
1919                                                 name, 0), "ebt_%s", name);
1920                 if (wt == NULL)
1921                         return -ENOENT;
1922                 if (IS_ERR(wt))
1923                         return PTR_ERR(wt);
1924                 off = xt_compat_target_offset(wt);
1925
1926                 if (dst) {
1927                         if (wt->compat_from_user)
1928                                 wt->compat_from_user(dst, mwt->data);
1929                         else
1930                                 memcpy(dst, mwt->data, match_size);
1931                 }
1932
1933                 size_kern = wt->targetsize;
1934                 module_put(wt->me);
1935                 break;
1936
1937         default:
1938                 return -EINVAL;
1939         }
1940
1941         state->buf_kern_offset += match_size + off;
1942         state->buf_user_offset += match_size;
1943         pad = XT_ALIGN(size_kern) - size_kern;
1944
1945         if (pad > 0 && dst) {
1946                 BUG_ON(state->buf_kern_len <= pad);
1947                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1948                 memset(dst + size_kern, 0, pad);
1949         }
1950         return off + match_size;
1951 }
1952
1953 /*
1954  * return size of all matches, watchers or target, including necessary
1955  * alignment and padding.
1956  */
1957 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1958                         unsigned int size_left, enum compat_mwt type,
1959                         struct ebt_entries_buf_state *state, const void *base)
1960 {
1961         int growth = 0;
1962         char *buf;
1963
1964         if (size_left == 0)
1965                 return 0;
1966
1967         buf = (char *) match32;
1968
1969         while (size_left >= sizeof(*match32)) {
1970                 struct ebt_entry_match *match_kern;
1971                 int ret;
1972
1973                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1974                 if (match_kern) {
1975                         char *tmp;
1976                         tmp = state->buf_kern_start + state->buf_kern_offset;
1977                         match_kern = (struct ebt_entry_match *) tmp;
1978                 }
1979                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1980                 if (ret < 0)
1981                         return ret;
1982                 size_left -= sizeof(*match32);
1983
1984                 /* add padding before match->data (if any) */
1985                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1986                 if (ret < 0)
1987                         return ret;
1988
1989                 if (match32->match_size > size_left)
1990                         return -EINVAL;
1991
1992                 size_left -= match32->match_size;
1993
1994                 ret = compat_mtw_from_user(match32, type, state, base);
1995                 if (ret < 0)
1996                         return ret;
1997
1998                 BUG_ON(ret < match32->match_size);
1999                 growth += ret - match32->match_size;
2000                 growth += ebt_compat_entry_padsize();
2001
2002                 buf += sizeof(*match32);
2003                 buf += match32->match_size;
2004
2005                 if (match_kern)
2006                         match_kern->match_size = ret;
2007
2008                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2009                 match32 = (struct compat_ebt_entry_mwt *) buf;
2010         }
2011
2012         return growth;
2013 }
2014
2015 /* called for all ebt_entry structures. */
2016 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2017                           unsigned int *total,
2018                           struct ebt_entries_buf_state *state)
2019 {
2020         unsigned int i, j, startoff, new_offset = 0;
2021         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2022         unsigned int offsets[4];
2023         unsigned int *offsets_update = NULL;
2024         int ret;
2025         char *buf_start;
2026
2027         if (*total < sizeof(struct ebt_entries))
2028                 return -EINVAL;
2029
2030         if (!entry->bitmask) {
2031                 *total -= sizeof(struct ebt_entries);
2032                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2033         }
2034         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2035                 return -EINVAL;
2036
2037         startoff = state->buf_user_offset;
2038         /* pull in most part of ebt_entry, it does not need to be changed. */
2039         ret = ebt_buf_add(state, entry,
2040                         offsetof(struct ebt_entry, watchers_offset));
2041         if (ret < 0)
2042                 return ret;
2043
2044         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2045         memcpy(&offsets[1], &entry->watchers_offset,
2046                         sizeof(offsets) - sizeof(offsets[0]));
2047
2048         if (state->buf_kern_start) {
2049                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2050                 offsets_update = (unsigned int *) buf_start;
2051         }
2052         ret = ebt_buf_add(state, &offsets[1],
2053                         sizeof(offsets) - sizeof(offsets[0]));
2054         if (ret < 0)
2055                 return ret;
2056         buf_start = (char *) entry;
2057         /*
2058          * 0: matches offset, always follows ebt_entry.
2059          * 1: watchers offset, from ebt_entry structure
2060          * 2: target offset, from ebt_entry structure
2061          * 3: next ebt_entry offset, from ebt_entry structure
2062          *
2063          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2064          */
2065         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2066                 struct compat_ebt_entry_mwt *match32;
2067                 unsigned int size;
2068                 char *buf = buf_start;
2069
2070                 buf = buf_start + offsets[i];
2071                 if (offsets[i] > offsets[j])
2072                         return -EINVAL;
2073
2074                 match32 = (struct compat_ebt_entry_mwt *) buf;
2075                 size = offsets[j] - offsets[i];
2076                 ret = ebt_size_mwt(match32, size, i, state, base);
2077                 if (ret < 0)
2078                         return ret;
2079                 new_offset += ret;
2080                 if (offsets_update && new_offset) {
2081                         pr_debug("change offset %d to %d\n",
2082                                 offsets_update[i], offsets[j] + new_offset);
2083                         offsets_update[i] = offsets[j] + new_offset;
2084                 }
2085         }
2086
2087         if (state->buf_kern_start == NULL) {
2088                 unsigned int offset = buf_start - (char *) base;
2089
2090                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2091                 if (ret < 0)
2092                         return ret;
2093         }
2094
2095         startoff = state->buf_user_offset - startoff;
2096
2097         BUG_ON(*total < startoff);
2098         *total -= startoff;
2099         return 0;
2100 }
2101
2102 /*
2103  * repl->entries_size is the size of the ebt_entry blob in userspace.
2104  * It might need more memory when copied to a 64 bit kernel in case
2105  * userspace is 32-bit. So, first task: find out how much memory is needed.
2106  *
2107  * Called before validation is performed.
2108  */
2109 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2110                                 struct ebt_entries_buf_state *state)
2111 {
2112         unsigned int size_remaining = size_user;
2113         int ret;
2114
2115         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2116                                         &size_remaining, state);
2117         if (ret < 0)
2118                 return ret;
2119
2120         WARN_ON(size_remaining);
2121         return state->buf_kern_offset;
2122 }
2123
2124
2125 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2126                                             void __user *user, unsigned int len)
2127 {
2128         struct compat_ebt_replace tmp;
2129         int i;
2130
2131         if (len < sizeof(tmp))
2132                 return -EINVAL;
2133
2134         if (copy_from_user(&tmp, user, sizeof(tmp)))
2135                 return -EFAULT;
2136
2137         if (len != sizeof(tmp) + tmp.entries_size)
2138                 return -EINVAL;
2139
2140         if (tmp.entries_size == 0)
2141                 return -EINVAL;
2142
2143         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2144                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2145                 return -ENOMEM;
2146         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2147                 return -ENOMEM;
2148
2149         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2150
2151         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2152         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2153                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2154
2155         repl->num_counters = tmp.num_counters;
2156         repl->counters = compat_ptr(tmp.counters);
2157         repl->entries = compat_ptr(tmp.entries);
2158         return 0;
2159 }
2160
2161 static int compat_do_replace(struct net *net, void __user *user,
2162                              unsigned int len)
2163 {
2164         int ret, i, countersize, size64;
2165         struct ebt_table_info *newinfo;
2166         struct ebt_replace tmp;
2167         struct ebt_entries_buf_state state;
2168         void *entries_tmp;
2169
2170         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2171         if (ret) {
2172                 /* try real handler in case userland supplied needed padding */
2173                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2174                         ret = 0;
2175                 return ret;
2176         }
2177
2178         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2179         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2180         if (!newinfo)
2181                 return -ENOMEM;
2182
2183         if (countersize)
2184                 memset(newinfo->counters, 0, countersize);
2185
2186         memset(&state, 0, sizeof(state));
2187
2188         newinfo->entries = vmalloc(tmp.entries_size);
2189         if (!newinfo->entries) {
2190                 ret = -ENOMEM;
2191                 goto free_newinfo;
2192         }
2193         if (copy_from_user(
2194            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2195                 ret = -EFAULT;
2196                 goto free_entries;
2197         }
2198
2199         entries_tmp = newinfo->entries;
2200
2201         xt_compat_lock(NFPROTO_BRIDGE);
2202
2203         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2204         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2205         if (ret < 0)
2206                 goto out_unlock;
2207
2208         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2209                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2210                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2211
2212         size64 = ret;
2213         newinfo->entries = vmalloc(size64);
2214         if (!newinfo->entries) {
2215                 vfree(entries_tmp);
2216                 ret = -ENOMEM;
2217                 goto out_unlock;
2218         }
2219
2220         memset(&state, 0, sizeof(state));
2221         state.buf_kern_start = newinfo->entries;
2222         state.buf_kern_len = size64;
2223
2224         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2225         BUG_ON(ret < 0);        /* parses same data again */
2226
2227         vfree(entries_tmp);
2228         tmp.entries_size = size64;
2229
2230         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2231                 char __user *usrptr;
2232                 if (tmp.hook_entry[i]) {
2233                         unsigned int delta;
2234                         usrptr = (char __user *) tmp.hook_entry[i];
2235                         delta = usrptr - tmp.entries;
2236                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2237                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2238                 }
2239         }
2240
2241         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2242         xt_compat_unlock(NFPROTO_BRIDGE);
2243
2244         ret = do_replace_finish(net, &tmp, newinfo);
2245         if (ret == 0)
2246                 return ret;
2247 free_entries:
2248         vfree(newinfo->entries);
2249 free_newinfo:
2250         vfree(newinfo);
2251         return ret;
2252 out_unlock:
2253         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2254         xt_compat_unlock(NFPROTO_BRIDGE);
2255         goto free_entries;
2256 }
2257
2258 static int compat_update_counters(struct net *net, void __user *user,
2259                                   unsigned int len)
2260 {
2261         struct compat_ebt_replace hlp;
2262
2263         if (copy_from_user(&hlp, user, sizeof(hlp)))
2264                 return -EFAULT;
2265
2266         /* try real handler in case userland supplied needed padding */
2267         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2268                 return update_counters(net, user, len);
2269
2270         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2271                                         hlp.num_counters, user, len);
2272 }
2273
2274 static int compat_do_ebt_set_ctl(struct sock *sk,
2275                 int cmd, void __user *user, unsigned int len)
2276 {
2277         int ret;
2278
2279         if (!capable(CAP_NET_ADMIN))
2280                 return -EPERM;
2281
2282         switch (cmd) {
2283         case EBT_SO_SET_ENTRIES:
2284                 ret = compat_do_replace(sock_net(sk), user, len);
2285                 break;
2286         case EBT_SO_SET_COUNTERS:
2287                 ret = compat_update_counters(sock_net(sk), user, len);
2288                 break;
2289         default:
2290                 ret = -EINVAL;
2291   }
2292         return ret;
2293 }
2294
2295 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2296                 void __user *user, int *len)
2297 {
2298         int ret;
2299         struct compat_ebt_replace tmp;
2300         struct ebt_table *t;
2301
2302         if (!capable(CAP_NET_ADMIN))
2303                 return -EPERM;
2304
2305         /* try real handler in case userland supplied needed padding */
2306         if ((cmd == EBT_SO_GET_INFO ||
2307              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2308                         return do_ebt_get_ctl(sk, cmd, user, len);
2309
2310         if (copy_from_user(&tmp, user, sizeof(tmp)))
2311                 return -EFAULT;
2312
2313         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
2314         if (!t)
2315                 return ret;
2316
2317         xt_compat_lock(NFPROTO_BRIDGE);
2318         switch (cmd) {
2319         case EBT_SO_GET_INFO:
2320                 tmp.nentries = t->private->nentries;
2321                 ret = compat_table_info(t->private, &tmp);
2322                 if (ret)
2323                         goto out;
2324                 tmp.valid_hooks = t->valid_hooks;
2325
2326                 if (copy_to_user(user, &tmp, *len) != 0) {
2327                         ret = -EFAULT;
2328                         break;
2329                 }
2330                 ret = 0;
2331                 break;
2332         case EBT_SO_GET_INIT_INFO:
2333                 tmp.nentries = t->table->nentries;
2334                 tmp.entries_size = t->table->entries_size;
2335                 tmp.valid_hooks = t->table->valid_hooks;
2336
2337                 if (copy_to_user(user, &tmp, *len) != 0) {
2338                         ret = -EFAULT;
2339                         break;
2340                 }
2341                 ret = 0;
2342                 break;
2343         case EBT_SO_GET_ENTRIES:
2344         case EBT_SO_GET_INIT_ENTRIES:
2345                 /*
2346                  * try real handler first in case of userland-side padding.
2347                  * in case we are dealing with an 'ordinary' 32 bit binary
2348                  * without 64bit compatibility padding, this will fail right
2349                  * after copy_from_user when the *len argument is validated.
2350                  *
2351                  * the compat_ variant needs to do one pass over the kernel
2352                  * data set to adjust for size differences before it the check.
2353                  */
2354                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2355                         ret = 0;
2356                 else
2357                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2358                 break;
2359         default:
2360                 ret = -EINVAL;
2361         }
2362  out:
2363         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2364         xt_compat_unlock(NFPROTO_BRIDGE);
2365         mutex_unlock(&ebt_mutex);
2366         return ret;
2367 }
2368 #endif
2369
2370 static struct nf_sockopt_ops ebt_sockopts =
2371 {
2372         .pf             = PF_INET,
2373         .set_optmin     = EBT_BASE_CTL,
2374         .set_optmax     = EBT_SO_SET_MAX + 1,
2375         .set            = do_ebt_set_ctl,
2376 #ifdef CONFIG_COMPAT
2377         .compat_set     = compat_do_ebt_set_ctl,
2378 #endif
2379         .get_optmin     = EBT_BASE_CTL,
2380         .get_optmax     = EBT_SO_GET_MAX + 1,
2381         .get            = do_ebt_get_ctl,
2382 #ifdef CONFIG_COMPAT
2383         .compat_get     = compat_do_ebt_get_ctl,
2384 #endif
2385         .owner          = THIS_MODULE,
2386 };
2387
2388 static int __init ebtables_init(void)
2389 {
2390         int ret;
2391
2392         ret = xt_register_target(&ebt_standard_target);
2393         if (ret < 0)
2394                 return ret;
2395         ret = nf_register_sockopt(&ebt_sockopts);
2396         if (ret < 0) {
2397                 xt_unregister_target(&ebt_standard_target);
2398                 return ret;
2399         }
2400
2401         printk(KERN_INFO "Ebtables v2.0 registered\n");
2402         return 0;
2403 }
2404
2405 static void __exit ebtables_fini(void)
2406 {
2407         nf_unregister_sockopt(&ebt_sockopts);
2408         xt_unregister_target(&ebt_standard_target);
2409         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2410 }
2411
2412 EXPORT_SYMBOL(ebt_register_table);
2413 EXPORT_SYMBOL(ebt_unregister_table);
2414 EXPORT_SYMBOL(ebt_do_table);
2415 module_init(ebtables_init);
2416 module_exit(ebtables_fini);
2417 MODULE_LICENSE("GPL");