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         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1339
1340         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1341            long. Copy 29 bytes and fill remaining bytes with zeroes. */
1342         strncpy(name, m->u.match->name, sizeof(name));
1343         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1344                 return -EFAULT;
1345         return 0;
1346 }
1347
1348 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1349     const char *base, char __user *ubase)
1350 {
1351         char __user *hlp = ubase + ((char *)w - base);
1352         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1353
1354         strncpy(name, w->u.watcher->name, sizeof(name));
1355         if (copy_to_user(hlp , name, EBT_FUNCTION_MAXNAMELEN))
1356                 return -EFAULT;
1357         return 0;
1358 }
1359
1360 static inline int
1361 ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase)
1362 {
1363         int ret;
1364         char __user *hlp;
1365         const struct ebt_entry_target *t;
1366         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1367
1368         if (e->bitmask == 0)
1369                 return 0;
1370
1371         hlp = ubase + (((char *)e + e->target_offset) - base);
1372         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1373
1374         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1375         if (ret != 0)
1376                 return ret;
1377         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1378         if (ret != 0)
1379                 return ret;
1380         strncpy(name, t->u.target->name, sizeof(name));
1381         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1382                 return -EFAULT;
1383         return 0;
1384 }
1385
1386 static int copy_counters_to_user(struct ebt_table *t,
1387                                   const struct ebt_counter *oldcounters,
1388                                   void __user *user, unsigned int num_counters,
1389                                   unsigned int nentries)
1390 {
1391         struct ebt_counter *counterstmp;
1392         int ret = 0;
1393
1394         /* userspace might not need the counters */
1395         if (num_counters == 0)
1396                 return 0;
1397
1398         if (num_counters != nentries) {
1399                 BUGPRINT("Num_counters wrong\n");
1400                 return -EINVAL;
1401         }
1402
1403         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1404         if (!counterstmp)
1405                 return -ENOMEM;
1406
1407         write_lock_bh(&t->lock);
1408         get_counters(oldcounters, counterstmp, nentries);
1409         write_unlock_bh(&t->lock);
1410
1411         if (copy_to_user(user, counterstmp,
1412            nentries * sizeof(struct ebt_counter)))
1413                 ret = -EFAULT;
1414         vfree(counterstmp);
1415         return ret;
1416 }
1417
1418 /* called with ebt_mutex locked */
1419 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1420     const int *len, int cmd)
1421 {
1422         struct ebt_replace tmp;
1423         const struct ebt_counter *oldcounters;
1424         unsigned int entries_size, nentries;
1425         int ret;
1426         char *entries;
1427
1428         if (cmd == EBT_SO_GET_ENTRIES) {
1429                 entries_size = t->private->entries_size;
1430                 nentries = t->private->nentries;
1431                 entries = t->private->entries;
1432                 oldcounters = t->private->counters;
1433         } else {
1434                 entries_size = t->table->entries_size;
1435                 nentries = t->table->nentries;
1436                 entries = t->table->entries;
1437                 oldcounters = t->table->counters;
1438         }
1439
1440         if (copy_from_user(&tmp, user, sizeof(tmp)))
1441                 return -EFAULT;
1442
1443         if (*len != sizeof(struct ebt_replace) + entries_size +
1444            (tmp.num_counters? nentries * sizeof(struct ebt_counter): 0))
1445                 return -EINVAL;
1446
1447         if (tmp.nentries != nentries) {
1448                 BUGPRINT("Nentries wrong\n");
1449                 return -EINVAL;
1450         }
1451
1452         if (tmp.entries_size != entries_size) {
1453                 BUGPRINT("Wrong size\n");
1454                 return -EINVAL;
1455         }
1456
1457         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1458                                         tmp.num_counters, nentries);
1459         if (ret)
1460                 return ret;
1461
1462         if (copy_to_user(tmp.entries, entries, entries_size)) {
1463                 BUGPRINT("Couldn't copy entries to userspace\n");
1464                 return -EFAULT;
1465         }
1466         /* set the match/watcher/target names right */
1467         return EBT_ENTRY_ITERATE(entries, entries_size,
1468            ebt_make_names, entries, tmp.entries);
1469 }
1470
1471 static int do_ebt_set_ctl(struct sock *sk,
1472         int cmd, void __user *user, unsigned int len)
1473 {
1474         int ret;
1475
1476         if (!capable(CAP_NET_ADMIN))
1477                 return -EPERM;
1478
1479         switch(cmd) {
1480         case EBT_SO_SET_ENTRIES:
1481                 ret = do_replace(sock_net(sk), user, len);
1482                 break;
1483         case EBT_SO_SET_COUNTERS:
1484                 ret = update_counters(sock_net(sk), user, len);
1485                 break;
1486         default:
1487                 ret = -EINVAL;
1488         }
1489         return ret;
1490 }
1491
1492 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1493 {
1494         int ret;
1495         struct ebt_replace tmp;
1496         struct ebt_table *t;
1497
1498         if (!capable(CAP_NET_ADMIN))
1499                 return -EPERM;
1500
1501         if (copy_from_user(&tmp, user, sizeof(tmp)))
1502                 return -EFAULT;
1503
1504         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
1505         if (!t)
1506                 return ret;
1507
1508         switch(cmd) {
1509         case EBT_SO_GET_INFO:
1510         case EBT_SO_GET_INIT_INFO:
1511                 if (*len != sizeof(struct ebt_replace)){
1512                         ret = -EINVAL;
1513                         mutex_unlock(&ebt_mutex);
1514                         break;
1515                 }
1516                 if (cmd == EBT_SO_GET_INFO) {
1517                         tmp.nentries = t->private->nentries;
1518                         tmp.entries_size = t->private->entries_size;
1519                         tmp.valid_hooks = t->valid_hooks;
1520                 } else {
1521                         tmp.nentries = t->table->nentries;
1522                         tmp.entries_size = t->table->entries_size;
1523                         tmp.valid_hooks = t->table->valid_hooks;
1524                 }
1525                 mutex_unlock(&ebt_mutex);
1526                 if (copy_to_user(user, &tmp, *len) != 0){
1527                         BUGPRINT("c2u Didn't work\n");
1528                         ret = -EFAULT;
1529                         break;
1530                 }
1531                 ret = 0;
1532                 break;
1533
1534         case EBT_SO_GET_ENTRIES:
1535         case EBT_SO_GET_INIT_ENTRIES:
1536                 ret = copy_everything_to_user(t, user, len, cmd);
1537                 mutex_unlock(&ebt_mutex);
1538                 break;
1539
1540         default:
1541                 mutex_unlock(&ebt_mutex);
1542                 ret = -EINVAL;
1543         }
1544
1545         return ret;
1546 }
1547
1548 #ifdef CONFIG_COMPAT
1549 /* 32 bit-userspace compatibility definitions. */
1550 struct compat_ebt_replace {
1551         char name[EBT_TABLE_MAXNAMELEN];
1552         compat_uint_t valid_hooks;
1553         compat_uint_t nentries;
1554         compat_uint_t entries_size;
1555         /* start of the chains */
1556         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1557         /* nr of counters userspace expects back */
1558         compat_uint_t num_counters;
1559         /* where the kernel will put the old counters. */
1560         compat_uptr_t counters;
1561         compat_uptr_t entries;
1562 };
1563
1564 /* struct ebt_entry_match, _target and _watcher have same layout */
1565 struct compat_ebt_entry_mwt {
1566         union {
1567                 char name[EBT_FUNCTION_MAXNAMELEN];
1568                 compat_uptr_t ptr;
1569         } u;
1570         compat_uint_t match_size;
1571         compat_uint_t data[0];
1572 };
1573
1574 /* account for possible padding between match_size and ->data */
1575 static int ebt_compat_entry_padsize(void)
1576 {
1577         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1578                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1579         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1580                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1581 }
1582
1583 static int ebt_compat_match_offset(const struct xt_match *match,
1584                                    unsigned int userlen)
1585 {
1586         /*
1587          * ebt_among needs special handling. The kernel .matchsize is
1588          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1589          * value is expected.
1590          * Example: userspace sends 4500, ebt_among.c wants 4504.
1591          */
1592         if (unlikely(match->matchsize == -1))
1593                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1594         return xt_compat_match_offset(match);
1595 }
1596
1597 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1598                                 unsigned int *size)
1599 {
1600         const struct xt_match *match = m->u.match;
1601         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1602         int off = ebt_compat_match_offset(match, m->match_size);
1603         compat_uint_t msize = m->match_size - off;
1604
1605         BUG_ON(off >= m->match_size);
1606
1607         if (copy_to_user(cm->u.name, match->name,
1608             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1609                 return -EFAULT;
1610
1611         if (match->compat_to_user) {
1612                 if (match->compat_to_user(cm->data, m->data))
1613                         return -EFAULT;
1614         } else if (copy_to_user(cm->data, m->data, msize))
1615                         return -EFAULT;
1616
1617         *size -= ebt_compat_entry_padsize() + off;
1618         *dstptr = cm->data;
1619         *dstptr += msize;
1620         return 0;
1621 }
1622
1623 static int compat_target_to_user(struct ebt_entry_target *t,
1624                                  void __user **dstptr,
1625                                  unsigned int *size)
1626 {
1627         const struct xt_target *target = t->u.target;
1628         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1629         int off = xt_compat_target_offset(target);
1630         compat_uint_t tsize = t->target_size - off;
1631
1632         BUG_ON(off >= t->target_size);
1633
1634         if (copy_to_user(cm->u.name, target->name,
1635             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1636                 return -EFAULT;
1637
1638         if (target->compat_to_user) {
1639                 if (target->compat_to_user(cm->data, t->data))
1640                         return -EFAULT;
1641         } else if (copy_to_user(cm->data, t->data, tsize))
1642                 return -EFAULT;
1643
1644         *size -= ebt_compat_entry_padsize() + off;
1645         *dstptr = cm->data;
1646         *dstptr += tsize;
1647         return 0;
1648 }
1649
1650 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1651                                   void __user **dstptr,
1652                                   unsigned int *size)
1653 {
1654         return compat_target_to_user((struct ebt_entry_target *)w,
1655                                                         dstptr, size);
1656 }
1657
1658 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1659                                 unsigned int *size)
1660 {
1661         struct ebt_entry_target *t;
1662         struct ebt_entry __user *ce;
1663         u32 watchers_offset, target_offset, next_offset;
1664         compat_uint_t origsize;
1665         int ret;
1666
1667         if (e->bitmask == 0) {
1668                 if (*size < sizeof(struct ebt_entries))
1669                         return -EINVAL;
1670                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1671                         return -EFAULT;
1672
1673                 *dstptr += sizeof(struct ebt_entries);
1674                 *size -= sizeof(struct ebt_entries);
1675                 return 0;
1676         }
1677
1678         if (*size < sizeof(*ce))
1679                 return -EINVAL;
1680
1681         ce = (struct ebt_entry __user *)*dstptr;
1682         if (copy_to_user(ce, e, sizeof(*ce)))
1683                 return -EFAULT;
1684
1685         origsize = *size;
1686         *dstptr += sizeof(*ce);
1687
1688         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1689         if (ret)
1690                 return ret;
1691         watchers_offset = e->watchers_offset - (origsize - *size);
1692
1693         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1694         if (ret)
1695                 return ret;
1696         target_offset = e->target_offset - (origsize - *size);
1697
1698         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1699
1700         ret = compat_target_to_user(t, dstptr, size);
1701         if (ret)
1702                 return ret;
1703         next_offset = e->next_offset - (origsize - *size);
1704
1705         if (put_user(watchers_offset, &ce->watchers_offset) ||
1706             put_user(target_offset, &ce->target_offset) ||
1707             put_user(next_offset, &ce->next_offset))
1708                 return -EFAULT;
1709
1710         *size -= sizeof(*ce);
1711         return 0;
1712 }
1713
1714 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1715 {
1716         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1717         *off += ebt_compat_entry_padsize();
1718         return 0;
1719 }
1720
1721 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1722 {
1723         *off += xt_compat_target_offset(w->u.watcher);
1724         *off += ebt_compat_entry_padsize();
1725         return 0;
1726 }
1727
1728 static int compat_calc_entry(const struct ebt_entry *e,
1729                              const struct ebt_table_info *info,
1730                              const void *base,
1731                              struct compat_ebt_replace *newinfo)
1732 {
1733         const struct ebt_entry_target *t;
1734         unsigned int entry_offset;
1735         int off, ret, i;
1736
1737         if (e->bitmask == 0)
1738                 return 0;
1739
1740         off = 0;
1741         entry_offset = (void *)e - base;
1742
1743         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1744         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1745
1746         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1747
1748         off += xt_compat_target_offset(t->u.target);
1749         off += ebt_compat_entry_padsize();
1750
1751         newinfo->entries_size -= off;
1752
1753         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1754         if (ret)
1755                 return ret;
1756
1757         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1758                 const void *hookptr = info->hook_entry[i];
1759                 if (info->hook_entry[i] &&
1760                     (e < (struct ebt_entry *)(base - hookptr))) {
1761                         newinfo->hook_entry[i] -= off;
1762                         pr_debug("0x%08X -> 0x%08X\n",
1763                                         newinfo->hook_entry[i] + off,
1764                                         newinfo->hook_entry[i]);
1765                 }
1766         }
1767
1768         return 0;
1769 }
1770
1771
1772 static int compat_table_info(const struct ebt_table_info *info,
1773                              struct compat_ebt_replace *newinfo)
1774 {
1775         unsigned int size = info->entries_size;
1776         const void *entries = info->entries;
1777
1778         newinfo->entries_size = size;
1779
1780         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1781         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1782                                                         entries, newinfo);
1783 }
1784
1785 static int compat_copy_everything_to_user(struct ebt_table *t,
1786                                           void __user *user, int *len, int cmd)
1787 {
1788         struct compat_ebt_replace repl, tmp;
1789         struct ebt_counter *oldcounters;
1790         struct ebt_table_info tinfo;
1791         int ret;
1792         void __user *pos;
1793
1794         memset(&tinfo, 0, sizeof(tinfo));
1795
1796         if (cmd == EBT_SO_GET_ENTRIES) {
1797                 tinfo.entries_size = t->private->entries_size;
1798                 tinfo.nentries = t->private->nentries;
1799                 tinfo.entries = t->private->entries;
1800                 oldcounters = t->private->counters;
1801         } else {
1802                 tinfo.entries_size = t->table->entries_size;
1803                 tinfo.nentries = t->table->nentries;
1804                 tinfo.entries = t->table->entries;
1805                 oldcounters = t->table->counters;
1806         }
1807
1808         if (copy_from_user(&tmp, user, sizeof(tmp)))
1809                 return -EFAULT;
1810
1811         if (tmp.nentries != tinfo.nentries ||
1812            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1813                 return -EINVAL;
1814
1815         memcpy(&repl, &tmp, sizeof(repl));
1816         if (cmd == EBT_SO_GET_ENTRIES)
1817                 ret = compat_table_info(t->private, &repl);
1818         else
1819                 ret = compat_table_info(&tinfo, &repl);
1820         if (ret)
1821                 return ret;
1822
1823         if (*len != sizeof(tmp) + repl.entries_size +
1824            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1825                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1826                                 *len, tinfo.entries_size, repl.entries_size);
1827                 return -EINVAL;
1828         }
1829
1830         /* userspace might not need the counters */
1831         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1832                                         tmp.num_counters, tinfo.nentries);
1833         if (ret)
1834                 return ret;
1835
1836         pos = compat_ptr(tmp.entries);
1837         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1838                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1839 }
1840
1841 struct ebt_entries_buf_state {
1842         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1843         u32 buf_kern_len;       /* total size of kernel buffer */
1844         u32 buf_kern_offset;    /* amount of data copied so far */
1845         u32 buf_user_offset;    /* read position in userspace buffer */
1846 };
1847
1848 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1849 {
1850         state->buf_kern_offset += sz;
1851         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1852 }
1853
1854 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1855                        void *data, unsigned int sz)
1856 {
1857         if (state->buf_kern_start == NULL)
1858                 goto count_only;
1859
1860         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1861
1862         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1863
1864  count_only:
1865         state->buf_user_offset += sz;
1866         return ebt_buf_count(state, sz);
1867 }
1868
1869 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1870 {
1871         char *b = state->buf_kern_start;
1872
1873         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1874
1875         if (b != NULL && sz > 0)
1876                 memset(b + state->buf_kern_offset, 0, sz);
1877         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1878         return ebt_buf_count(state, sz);
1879 }
1880
1881 enum compat_mwt {
1882         EBT_COMPAT_MATCH,
1883         EBT_COMPAT_WATCHER,
1884         EBT_COMPAT_TARGET,
1885 };
1886
1887 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1888                                 enum compat_mwt compat_mwt,
1889                                 struct ebt_entries_buf_state *state,
1890                                 const unsigned char *base)
1891 {
1892         char name[EBT_FUNCTION_MAXNAMELEN];
1893         struct xt_match *match;
1894         struct xt_target *wt;
1895         void *dst = NULL;
1896         int off, pad = 0;
1897         unsigned int size_kern, match_size = mwt->match_size;
1898
1899         strlcpy(name, mwt->u.name, sizeof(name));
1900
1901         if (state->buf_kern_start)
1902                 dst = state->buf_kern_start + state->buf_kern_offset;
1903
1904         switch (compat_mwt) {
1905         case EBT_COMPAT_MATCH:
1906                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1907                 if (IS_ERR(match))
1908                         return PTR_ERR(match);
1909
1910                 off = ebt_compat_match_offset(match, match_size);
1911                 if (dst) {
1912                         if (match->compat_from_user)
1913                                 match->compat_from_user(dst, mwt->data);
1914                         else
1915                                 memcpy(dst, mwt->data, match_size);
1916                 }
1917
1918                 size_kern = match->matchsize;
1919                 if (unlikely(size_kern == -1))
1920                         size_kern = match_size;
1921                 module_put(match->me);
1922                 break;
1923         case EBT_COMPAT_WATCHER: /* fallthrough */
1924         case EBT_COMPAT_TARGET:
1925                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1926                 if (IS_ERR(wt))
1927                         return PTR_ERR(wt);
1928                 off = xt_compat_target_offset(wt);
1929
1930                 if (dst) {
1931                         if (wt->compat_from_user)
1932                                 wt->compat_from_user(dst, mwt->data);
1933                         else
1934                                 memcpy(dst, mwt->data, match_size);
1935                 }
1936
1937                 size_kern = wt->targetsize;
1938                 module_put(wt->me);
1939                 break;
1940
1941         default:
1942                 return -EINVAL;
1943         }
1944
1945         state->buf_kern_offset += match_size + off;
1946         state->buf_user_offset += match_size;
1947         pad = XT_ALIGN(size_kern) - size_kern;
1948
1949         if (pad > 0 && dst) {
1950                 BUG_ON(state->buf_kern_len <= pad);
1951                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1952                 memset(dst + size_kern, 0, pad);
1953         }
1954         return off + match_size;
1955 }
1956
1957 /*
1958  * return size of all matches, watchers or target, including necessary
1959  * alignment and padding.
1960  */
1961 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1962                         unsigned int size_left, enum compat_mwt type,
1963                         struct ebt_entries_buf_state *state, const void *base)
1964 {
1965         int growth = 0;
1966         char *buf;
1967
1968         if (size_left == 0)
1969                 return 0;
1970
1971         buf = (char *) match32;
1972
1973         while (size_left >= sizeof(*match32)) {
1974                 struct ebt_entry_match *match_kern;
1975                 int ret;
1976
1977                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1978                 if (match_kern) {
1979                         char *tmp;
1980                         tmp = state->buf_kern_start + state->buf_kern_offset;
1981                         match_kern = (struct ebt_entry_match *) tmp;
1982                 }
1983                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1984                 if (ret < 0)
1985                         return ret;
1986                 size_left -= sizeof(*match32);
1987
1988                 /* add padding before match->data (if any) */
1989                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1990                 if (ret < 0)
1991                         return ret;
1992
1993                 if (match32->match_size > size_left)
1994                         return -EINVAL;
1995
1996                 size_left -= match32->match_size;
1997
1998                 ret = compat_mtw_from_user(match32, type, state, base);
1999                 if (ret < 0)
2000                         return ret;
2001
2002                 BUG_ON(ret < match32->match_size);
2003                 growth += ret - match32->match_size;
2004                 growth += ebt_compat_entry_padsize();
2005
2006                 buf += sizeof(*match32);
2007                 buf += match32->match_size;
2008
2009                 if (match_kern)
2010                         match_kern->match_size = ret;
2011
2012                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2013                 match32 = (struct compat_ebt_entry_mwt *) buf;
2014         }
2015
2016         return growth;
2017 }
2018
2019 /* called for all ebt_entry structures. */
2020 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2021                           unsigned int *total,
2022                           struct ebt_entries_buf_state *state)
2023 {
2024         unsigned int i, j, startoff, new_offset = 0;
2025         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2026         unsigned int offsets[4];
2027         unsigned int *offsets_update = NULL;
2028         int ret;
2029         char *buf_start;
2030
2031         if (*total < sizeof(struct ebt_entries))
2032                 return -EINVAL;
2033
2034         if (!entry->bitmask) {
2035                 *total -= sizeof(struct ebt_entries);
2036                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2037         }
2038         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2039                 return -EINVAL;
2040
2041         startoff = state->buf_user_offset;
2042         /* pull in most part of ebt_entry, it does not need to be changed. */
2043         ret = ebt_buf_add(state, entry,
2044                         offsetof(struct ebt_entry, watchers_offset));
2045         if (ret < 0)
2046                 return ret;
2047
2048         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2049         memcpy(&offsets[1], &entry->watchers_offset,
2050                         sizeof(offsets) - sizeof(offsets[0]));
2051
2052         if (state->buf_kern_start) {
2053                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2054                 offsets_update = (unsigned int *) buf_start;
2055         }
2056         ret = ebt_buf_add(state, &offsets[1],
2057                         sizeof(offsets) - sizeof(offsets[0]));
2058         if (ret < 0)
2059                 return ret;
2060         buf_start = (char *) entry;
2061         /*
2062          * 0: matches offset, always follows ebt_entry.
2063          * 1: watchers offset, from ebt_entry structure
2064          * 2: target offset, from ebt_entry structure
2065          * 3: next ebt_entry offset, from ebt_entry structure
2066          *
2067          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2068          */
2069         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2070                 struct compat_ebt_entry_mwt *match32;
2071                 unsigned int size;
2072                 char *buf = buf_start;
2073
2074                 buf = buf_start + offsets[i];
2075                 if (offsets[i] > offsets[j])
2076                         return -EINVAL;
2077
2078                 match32 = (struct compat_ebt_entry_mwt *) buf;
2079                 size = offsets[j] - offsets[i];
2080                 ret = ebt_size_mwt(match32, size, i, state, base);
2081                 if (ret < 0)
2082                         return ret;
2083                 new_offset += ret;
2084                 if (offsets_update && new_offset) {
2085                         pr_debug("change offset %d to %d\n",
2086                                 offsets_update[i], offsets[j] + new_offset);
2087                         offsets_update[i] = offsets[j] + new_offset;
2088                 }
2089         }
2090
2091         if (state->buf_kern_start == NULL) {
2092                 unsigned int offset = buf_start - (char *) base;
2093
2094                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2095                 if (ret < 0)
2096                         return ret;
2097         }
2098
2099         startoff = state->buf_user_offset - startoff;
2100
2101         BUG_ON(*total < startoff);
2102         *total -= startoff;
2103         return 0;
2104 }
2105
2106 /*
2107  * repl->entries_size is the size of the ebt_entry blob in userspace.
2108  * It might need more memory when copied to a 64 bit kernel in case
2109  * userspace is 32-bit. So, first task: find out how much memory is needed.
2110  *
2111  * Called before validation is performed.
2112  */
2113 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2114                                 struct ebt_entries_buf_state *state)
2115 {
2116         unsigned int size_remaining = size_user;
2117         int ret;
2118
2119         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2120                                         &size_remaining, state);
2121         if (ret < 0)
2122                 return ret;
2123
2124         WARN_ON(size_remaining);
2125         return state->buf_kern_offset;
2126 }
2127
2128
2129 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2130                                             void __user *user, unsigned int len)
2131 {
2132         struct compat_ebt_replace tmp;
2133         int i;
2134
2135         if (len < sizeof(tmp))
2136                 return -EINVAL;
2137
2138         if (copy_from_user(&tmp, user, sizeof(tmp)))
2139                 return -EFAULT;
2140
2141         if (len != sizeof(tmp) + tmp.entries_size)
2142                 return -EINVAL;
2143
2144         if (tmp.entries_size == 0)
2145                 return -EINVAL;
2146
2147         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2148                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2149                 return -ENOMEM;
2150         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2151                 return -ENOMEM;
2152
2153         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2154
2155         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2156         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2157                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2158
2159         repl->num_counters = tmp.num_counters;
2160         repl->counters = compat_ptr(tmp.counters);
2161         repl->entries = compat_ptr(tmp.entries);
2162         return 0;
2163 }
2164
2165 static int compat_do_replace(struct net *net, void __user *user,
2166                              unsigned int len)
2167 {
2168         int ret, i, countersize, size64;
2169         struct ebt_table_info *newinfo;
2170         struct ebt_replace tmp;
2171         struct ebt_entries_buf_state state;
2172         void *entries_tmp;
2173
2174         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2175         if (ret) {
2176                 /* try real handler in case userland supplied needed padding */
2177                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2178                         ret = 0;
2179                 return ret;
2180         }
2181
2182         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2183         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2184         if (!newinfo)
2185                 return -ENOMEM;
2186
2187         if (countersize)
2188                 memset(newinfo->counters, 0, countersize);
2189
2190         memset(&state, 0, sizeof(state));
2191
2192         newinfo->entries = vmalloc(tmp.entries_size);
2193         if (!newinfo->entries) {
2194                 ret = -ENOMEM;
2195                 goto free_newinfo;
2196         }
2197         if (copy_from_user(
2198            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2199                 ret = -EFAULT;
2200                 goto free_entries;
2201         }
2202
2203         entries_tmp = newinfo->entries;
2204
2205         xt_compat_lock(NFPROTO_BRIDGE);
2206
2207         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2208         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2209         if (ret < 0)
2210                 goto out_unlock;
2211
2212         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2213                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2214                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2215
2216         size64 = ret;
2217         newinfo->entries = vmalloc(size64);
2218         if (!newinfo->entries) {
2219                 vfree(entries_tmp);
2220                 ret = -ENOMEM;
2221                 goto out_unlock;
2222         }
2223
2224         memset(&state, 0, sizeof(state));
2225         state.buf_kern_start = newinfo->entries;
2226         state.buf_kern_len = size64;
2227
2228         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2229         BUG_ON(ret < 0);        /* parses same data again */
2230
2231         vfree(entries_tmp);
2232         tmp.entries_size = size64;
2233
2234         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2235                 char __user *usrptr;
2236                 if (tmp.hook_entry[i]) {
2237                         unsigned int delta;
2238                         usrptr = (char __user *) tmp.hook_entry[i];
2239                         delta = usrptr - tmp.entries;
2240                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2241                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2242                 }
2243         }
2244
2245         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2246         xt_compat_unlock(NFPROTO_BRIDGE);
2247
2248         ret = do_replace_finish(net, &tmp, newinfo);
2249         if (ret == 0)
2250                 return ret;
2251 free_entries:
2252         vfree(newinfo->entries);
2253 free_newinfo:
2254         vfree(newinfo);
2255         return ret;
2256 out_unlock:
2257         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2258         xt_compat_unlock(NFPROTO_BRIDGE);
2259         goto free_entries;
2260 }
2261
2262 static int compat_update_counters(struct net *net, void __user *user,
2263                                   unsigned int len)
2264 {
2265         struct compat_ebt_replace hlp;
2266
2267         if (copy_from_user(&hlp, user, sizeof(hlp)))
2268                 return -EFAULT;
2269
2270         /* try real handler in case userland supplied needed padding */
2271         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2272                 return update_counters(net, user, len);
2273
2274         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2275                                         hlp.num_counters, user, len);
2276 }
2277
2278 static int compat_do_ebt_set_ctl(struct sock *sk,
2279                 int cmd, void __user *user, unsigned int len)
2280 {
2281         int ret;
2282
2283         if (!capable(CAP_NET_ADMIN))
2284                 return -EPERM;
2285
2286         switch (cmd) {
2287         case EBT_SO_SET_ENTRIES:
2288                 ret = compat_do_replace(sock_net(sk), user, len);
2289                 break;
2290         case EBT_SO_SET_COUNTERS:
2291                 ret = compat_update_counters(sock_net(sk), user, len);
2292                 break;
2293         default:
2294                 ret = -EINVAL;
2295   }
2296         return ret;
2297 }
2298
2299 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2300                 void __user *user, int *len)
2301 {
2302         int ret;
2303         struct compat_ebt_replace tmp;
2304         struct ebt_table *t;
2305
2306         if (!capable(CAP_NET_ADMIN))
2307                 return -EPERM;
2308
2309         /* try real handler in case userland supplied needed padding */
2310         if ((cmd == EBT_SO_GET_INFO ||
2311              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2312                         return do_ebt_get_ctl(sk, cmd, user, len);
2313
2314         if (copy_from_user(&tmp, user, sizeof(tmp)))
2315                 return -EFAULT;
2316
2317         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
2318         if (!t)
2319                 return ret;
2320
2321         xt_compat_lock(NFPROTO_BRIDGE);
2322         switch (cmd) {
2323         case EBT_SO_GET_INFO:
2324                 tmp.nentries = t->private->nentries;
2325                 ret = compat_table_info(t->private, &tmp);
2326                 if (ret)
2327                         goto out;
2328                 tmp.valid_hooks = t->valid_hooks;
2329
2330                 if (copy_to_user(user, &tmp, *len) != 0) {
2331                         ret = -EFAULT;
2332                         break;
2333                 }
2334                 ret = 0;
2335                 break;
2336         case EBT_SO_GET_INIT_INFO:
2337                 tmp.nentries = t->table->nentries;
2338                 tmp.entries_size = t->table->entries_size;
2339                 tmp.valid_hooks = t->table->valid_hooks;
2340
2341                 if (copy_to_user(user, &tmp, *len) != 0) {
2342                         ret = -EFAULT;
2343                         break;
2344                 }
2345                 ret = 0;
2346                 break;
2347         case EBT_SO_GET_ENTRIES:
2348         case EBT_SO_GET_INIT_ENTRIES:
2349                 /*
2350                  * try real handler first in case of userland-side padding.
2351                  * in case we are dealing with an 'ordinary' 32 bit binary
2352                  * without 64bit compatibility padding, this will fail right
2353                  * after copy_from_user when the *len argument is validated.
2354                  *
2355                  * the compat_ variant needs to do one pass over the kernel
2356                  * data set to adjust for size differences before it the check.
2357                  */
2358                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2359                         ret = 0;
2360                 else
2361                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2362                 break;
2363         default:
2364                 ret = -EINVAL;
2365         }
2366  out:
2367         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2368         xt_compat_unlock(NFPROTO_BRIDGE);
2369         mutex_unlock(&ebt_mutex);
2370         return ret;
2371 }
2372 #endif
2373
2374 static struct nf_sockopt_ops ebt_sockopts =
2375 {
2376         .pf             = PF_INET,
2377         .set_optmin     = EBT_BASE_CTL,
2378         .set_optmax     = EBT_SO_SET_MAX + 1,
2379         .set            = do_ebt_set_ctl,
2380 #ifdef CONFIG_COMPAT
2381         .compat_set     = compat_do_ebt_set_ctl,
2382 #endif
2383         .get_optmin     = EBT_BASE_CTL,
2384         .get_optmax     = EBT_SO_GET_MAX + 1,
2385         .get            = do_ebt_get_ctl,
2386 #ifdef CONFIG_COMPAT
2387         .compat_get     = compat_do_ebt_get_ctl,
2388 #endif
2389         .owner          = THIS_MODULE,
2390 };
2391
2392 static int __init ebtables_init(void)
2393 {
2394         int ret;
2395
2396         ret = xt_register_target(&ebt_standard_target);
2397         if (ret < 0)
2398                 return ret;
2399         ret = nf_register_sockopt(&ebt_sockopts);
2400         if (ret < 0) {
2401                 xt_unregister_target(&ebt_standard_target);
2402                 return ret;
2403         }
2404
2405         printk(KERN_INFO "Ebtables v2.0 registered\n");
2406         return 0;
2407 }
2408
2409 static void __exit ebtables_fini(void)
2410 {
2411         nf_unregister_sockopt(&ebt_sockopts);
2412         xt_unregister_target(&ebt_standard_target);
2413         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2414 }
2415
2416 EXPORT_SYMBOL(ebt_register_table);
2417 EXPORT_SYMBOL(ebt_unregister_table);
2418 EXPORT_SYMBOL(ebt_do_table);
2419 module_init(ebtables_init);
2420 module_exit(ebtables_fini);
2421 MODULE_LICENSE("GPL");