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                 return ERR_PTR(-EINVAL);
1202         }
1203
1204         table->private = newinfo;
1205         rwlock_init(&table->lock);
1206         ret = mutex_lock_interruptible(&ebt_mutex);
1207         if (ret != 0)
1208                 goto free_chainstack;
1209
1210         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1211                 if (strcmp(t->name, table->name) == 0) {
1212                         ret = -EEXIST;
1213                         BUGPRINT("Table name already exists\n");
1214                         goto free_unlock;
1215                 }
1216         }
1217
1218         /* Hold a reference count if the chains aren't empty */
1219         if (newinfo->nentries && !try_module_get(table->me)) {
1220                 ret = -ENOENT;
1221                 goto free_unlock;
1222         }
1223         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1224         mutex_unlock(&ebt_mutex);
1225         return table;
1226 free_unlock:
1227         mutex_unlock(&ebt_mutex);
1228 free_chainstack:
1229         if (newinfo->chainstack) {
1230                 for_each_possible_cpu(i)
1231                         vfree(newinfo->chainstack[i]);
1232                 vfree(newinfo->chainstack);
1233         }
1234         vfree(newinfo->entries);
1235 free_newinfo:
1236         vfree(newinfo);
1237 free_table:
1238         kfree(table);
1239 out:
1240         return ERR_PTR(ret);
1241 }
1242
1243 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1244 {
1245         int i;
1246
1247         if (!table) {
1248                 BUGPRINT("Request to unregister NULL table!!!\n");
1249                 return;
1250         }
1251         mutex_lock(&ebt_mutex);
1252         list_del(&table->list);
1253         mutex_unlock(&ebt_mutex);
1254         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1255                           ebt_cleanup_entry, net, NULL);
1256         if (table->private->nentries)
1257                 module_put(table->me);
1258         vfree(table->private->entries);
1259         if (table->private->chainstack) {
1260                 for_each_possible_cpu(i)
1261                         vfree(table->private->chainstack[i]);
1262                 vfree(table->private->chainstack);
1263         }
1264         vfree(table->private);
1265         kfree(table);
1266 }
1267
1268 /* userspace just supplied us with counters */
1269 static int do_update_counters(struct net *net, const char *name,
1270                                 struct ebt_counter __user *counters,
1271                                 unsigned int num_counters,
1272                                 const void __user *user, unsigned int len)
1273 {
1274         int i, ret;
1275         struct ebt_counter *tmp;
1276         struct ebt_table *t;
1277
1278         if (num_counters == 0)
1279                 return -EINVAL;
1280
1281         tmp = vmalloc(num_counters * sizeof(*tmp));
1282         if (!tmp)
1283                 return -ENOMEM;
1284
1285         t = find_table_lock(net, name, &ret, &ebt_mutex);
1286         if (!t)
1287                 goto free_tmp;
1288
1289         if (num_counters != t->private->nentries) {
1290                 BUGPRINT("Wrong nr of counters\n");
1291                 ret = -EINVAL;
1292                 goto unlock_mutex;
1293         }
1294
1295         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1296                 ret = -EFAULT;
1297                 goto unlock_mutex;
1298         }
1299
1300         /* we want an atomic add of the counters */
1301         write_lock_bh(&t->lock);
1302
1303         /* we add to the counters of the first cpu */
1304         for (i = 0; i < num_counters; i++) {
1305                 t->private->counters[i].pcnt += tmp[i].pcnt;
1306                 t->private->counters[i].bcnt += tmp[i].bcnt;
1307         }
1308
1309         write_unlock_bh(&t->lock);
1310         ret = 0;
1311 unlock_mutex:
1312         mutex_unlock(&ebt_mutex);
1313 free_tmp:
1314         vfree(tmp);
1315         return ret;
1316 }
1317
1318 static int update_counters(struct net *net, const void __user *user,
1319                             unsigned int len)
1320 {
1321         struct ebt_replace hlp;
1322
1323         if (copy_from_user(&hlp, user, sizeof(hlp)))
1324                 return -EFAULT;
1325
1326         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1327                 return -EINVAL;
1328
1329         return do_update_counters(net, hlp.name, hlp.counters,
1330                                 hlp.num_counters, user, len);
1331 }
1332
1333 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1334     const char *base, char __user *ubase)
1335 {
1336         char __user *hlp = ubase + ((char *)m - base);
1337         if (copy_to_user(hlp, m->u.match->name, EBT_FUNCTION_MAXNAMELEN))
1338                 return -EFAULT;
1339         return 0;
1340 }
1341
1342 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1343     const char *base, char __user *ubase)
1344 {
1345         char __user *hlp = ubase + ((char *)w - base);
1346         if (copy_to_user(hlp , w->u.watcher->name, EBT_FUNCTION_MAXNAMELEN))
1347                 return -EFAULT;
1348         return 0;
1349 }
1350
1351 static inline int
1352 ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase)
1353 {
1354         int ret;
1355         char __user *hlp;
1356         const struct ebt_entry_target *t;
1357
1358         if (e->bitmask == 0)
1359                 return 0;
1360
1361         hlp = ubase + (((char *)e + e->target_offset) - base);
1362         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1363
1364         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1365         if (ret != 0)
1366                 return ret;
1367         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1368         if (ret != 0)
1369                 return ret;
1370         if (copy_to_user(hlp, t->u.target->name, EBT_FUNCTION_MAXNAMELEN))
1371                 return -EFAULT;
1372         return 0;
1373 }
1374
1375 static int copy_counters_to_user(struct ebt_table *t,
1376                                   const struct ebt_counter *oldcounters,
1377                                   void __user *user, unsigned int num_counters,
1378                                   unsigned int nentries)
1379 {
1380         struct ebt_counter *counterstmp;
1381         int ret = 0;
1382
1383         /* userspace might not need the counters */
1384         if (num_counters == 0)
1385                 return 0;
1386
1387         if (num_counters != nentries) {
1388                 BUGPRINT("Num_counters wrong\n");
1389                 return -EINVAL;
1390         }
1391
1392         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1393         if (!counterstmp)
1394                 return -ENOMEM;
1395
1396         write_lock_bh(&t->lock);
1397         get_counters(oldcounters, counterstmp, nentries);
1398         write_unlock_bh(&t->lock);
1399
1400         if (copy_to_user(user, counterstmp,
1401            nentries * sizeof(struct ebt_counter)))
1402                 ret = -EFAULT;
1403         vfree(counterstmp);
1404         return ret;
1405 }
1406
1407 /* called with ebt_mutex locked */
1408 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1409     const int *len, int cmd)
1410 {
1411         struct ebt_replace tmp;
1412         const struct ebt_counter *oldcounters;
1413         unsigned int entries_size, nentries;
1414         int ret;
1415         char *entries;
1416
1417         if (cmd == EBT_SO_GET_ENTRIES) {
1418                 entries_size = t->private->entries_size;
1419                 nentries = t->private->nentries;
1420                 entries = t->private->entries;
1421                 oldcounters = t->private->counters;
1422         } else {
1423                 entries_size = t->table->entries_size;
1424                 nentries = t->table->nentries;
1425                 entries = t->table->entries;
1426                 oldcounters = t->table->counters;
1427         }
1428
1429         if (copy_from_user(&tmp, user, sizeof(tmp)))
1430                 return -EFAULT;
1431
1432         if (*len != sizeof(struct ebt_replace) + entries_size +
1433            (tmp.num_counters? nentries * sizeof(struct ebt_counter): 0))
1434                 return -EINVAL;
1435
1436         if (tmp.nentries != nentries) {
1437                 BUGPRINT("Nentries wrong\n");
1438                 return -EINVAL;
1439         }
1440
1441         if (tmp.entries_size != entries_size) {
1442                 BUGPRINT("Wrong size\n");
1443                 return -EINVAL;
1444         }
1445
1446         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1447                                         tmp.num_counters, nentries);
1448         if (ret)
1449                 return ret;
1450
1451         if (copy_to_user(tmp.entries, entries, entries_size)) {
1452                 BUGPRINT("Couldn't copy entries to userspace\n");
1453                 return -EFAULT;
1454         }
1455         /* set the match/watcher/target names right */
1456         return EBT_ENTRY_ITERATE(entries, entries_size,
1457            ebt_make_names, entries, tmp.entries);
1458 }
1459
1460 static int do_ebt_set_ctl(struct sock *sk,
1461         int cmd, void __user *user, unsigned int len)
1462 {
1463         int ret;
1464
1465         if (!capable(CAP_NET_ADMIN))
1466                 return -EPERM;
1467
1468         switch(cmd) {
1469         case EBT_SO_SET_ENTRIES:
1470                 ret = do_replace(sock_net(sk), user, len);
1471                 break;
1472         case EBT_SO_SET_COUNTERS:
1473                 ret = update_counters(sock_net(sk), user, len);
1474                 break;
1475         default:
1476                 ret = -EINVAL;
1477         }
1478         return ret;
1479 }
1480
1481 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1482 {
1483         int ret;
1484         struct ebt_replace tmp;
1485         struct ebt_table *t;
1486
1487         if (!capable(CAP_NET_ADMIN))
1488                 return -EPERM;
1489
1490         if (copy_from_user(&tmp, user, sizeof(tmp)))
1491                 return -EFAULT;
1492
1493         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
1494         if (!t)
1495                 return ret;
1496
1497         switch(cmd) {
1498         case EBT_SO_GET_INFO:
1499         case EBT_SO_GET_INIT_INFO:
1500                 if (*len != sizeof(struct ebt_replace)){
1501                         ret = -EINVAL;
1502                         mutex_unlock(&ebt_mutex);
1503                         break;
1504                 }
1505                 if (cmd == EBT_SO_GET_INFO) {
1506                         tmp.nentries = t->private->nentries;
1507                         tmp.entries_size = t->private->entries_size;
1508                         tmp.valid_hooks = t->valid_hooks;
1509                 } else {
1510                         tmp.nentries = t->table->nentries;
1511                         tmp.entries_size = t->table->entries_size;
1512                         tmp.valid_hooks = t->table->valid_hooks;
1513                 }
1514                 mutex_unlock(&ebt_mutex);
1515                 if (copy_to_user(user, &tmp, *len) != 0){
1516                         BUGPRINT("c2u Didn't work\n");
1517                         ret = -EFAULT;
1518                         break;
1519                 }
1520                 ret = 0;
1521                 break;
1522
1523         case EBT_SO_GET_ENTRIES:
1524         case EBT_SO_GET_INIT_ENTRIES:
1525                 ret = copy_everything_to_user(t, user, len, cmd);
1526                 mutex_unlock(&ebt_mutex);
1527                 break;
1528
1529         default:
1530                 mutex_unlock(&ebt_mutex);
1531                 ret = -EINVAL;
1532         }
1533
1534         return ret;
1535 }
1536
1537 #ifdef CONFIG_COMPAT
1538 /* 32 bit-userspace compatibility definitions. */
1539 struct compat_ebt_replace {
1540         char name[EBT_TABLE_MAXNAMELEN];
1541         compat_uint_t valid_hooks;
1542         compat_uint_t nentries;
1543         compat_uint_t entries_size;
1544         /* start of the chains */
1545         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1546         /* nr of counters userspace expects back */
1547         compat_uint_t num_counters;
1548         /* where the kernel will put the old counters. */
1549         compat_uptr_t counters;
1550         compat_uptr_t entries;
1551 };
1552
1553 /* struct ebt_entry_match, _target and _watcher have same layout */
1554 struct compat_ebt_entry_mwt {
1555         union {
1556                 char name[EBT_FUNCTION_MAXNAMELEN];
1557                 compat_uptr_t ptr;
1558         } u;
1559         compat_uint_t match_size;
1560         compat_uint_t data[0];
1561 };
1562
1563 /* account for possible padding between match_size and ->data */
1564 static int ebt_compat_entry_padsize(void)
1565 {
1566         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1567                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1568         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1569                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1570 }
1571
1572 static int ebt_compat_match_offset(const struct xt_match *match,
1573                                    unsigned int userlen)
1574 {
1575         /*
1576          * ebt_among needs special handling. The kernel .matchsize is
1577          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1578          * value is expected.
1579          * Example: userspace sends 4500, ebt_among.c wants 4504.
1580          */
1581         if (unlikely(match->matchsize == -1))
1582                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1583         return xt_compat_match_offset(match);
1584 }
1585
1586 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1587                                 unsigned int *size)
1588 {
1589         const struct xt_match *match = m->u.match;
1590         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1591         int off = ebt_compat_match_offset(match, m->match_size);
1592         compat_uint_t msize = m->match_size - off;
1593
1594         BUG_ON(off >= m->match_size);
1595
1596         if (copy_to_user(cm->u.name, match->name,
1597             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1598                 return -EFAULT;
1599
1600         if (match->compat_to_user) {
1601                 if (match->compat_to_user(cm->data, m->data))
1602                         return -EFAULT;
1603         } else if (copy_to_user(cm->data, m->data, msize))
1604                         return -EFAULT;
1605
1606         *size -= ebt_compat_entry_padsize() + off;
1607         *dstptr = cm->data;
1608         *dstptr += msize;
1609         return 0;
1610 }
1611
1612 static int compat_target_to_user(struct ebt_entry_target *t,
1613                                  void __user **dstptr,
1614                                  unsigned int *size)
1615 {
1616         const struct xt_target *target = t->u.target;
1617         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1618         int off = xt_compat_target_offset(target);
1619         compat_uint_t tsize = t->target_size - off;
1620
1621         BUG_ON(off >= t->target_size);
1622
1623         if (copy_to_user(cm->u.name, target->name,
1624             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1625                 return -EFAULT;
1626
1627         if (target->compat_to_user) {
1628                 if (target->compat_to_user(cm->data, t->data))
1629                         return -EFAULT;
1630         } else if (copy_to_user(cm->data, t->data, tsize))
1631                 return -EFAULT;
1632
1633         *size -= ebt_compat_entry_padsize() + off;
1634         *dstptr = cm->data;
1635         *dstptr += tsize;
1636         return 0;
1637 }
1638
1639 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1640                                   void __user **dstptr,
1641                                   unsigned int *size)
1642 {
1643         return compat_target_to_user((struct ebt_entry_target *)w,
1644                                                         dstptr, size);
1645 }
1646
1647 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1648                                 unsigned int *size)
1649 {
1650         struct ebt_entry_target *t;
1651         struct ebt_entry __user *ce;
1652         u32 watchers_offset, target_offset, next_offset;
1653         compat_uint_t origsize;
1654         int ret;
1655
1656         if (e->bitmask == 0) {
1657                 if (*size < sizeof(struct ebt_entries))
1658                         return -EINVAL;
1659                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1660                         return -EFAULT;
1661
1662                 *dstptr += sizeof(struct ebt_entries);
1663                 *size -= sizeof(struct ebt_entries);
1664                 return 0;
1665         }
1666
1667         if (*size < sizeof(*ce))
1668                 return -EINVAL;
1669
1670         ce = (struct ebt_entry __user *)*dstptr;
1671         if (copy_to_user(ce, e, sizeof(*ce)))
1672                 return -EFAULT;
1673
1674         origsize = *size;
1675         *dstptr += sizeof(*ce);
1676
1677         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1678         if (ret)
1679                 return ret;
1680         watchers_offset = e->watchers_offset - (origsize - *size);
1681
1682         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1683         if (ret)
1684                 return ret;
1685         target_offset = e->target_offset - (origsize - *size);
1686
1687         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1688
1689         ret = compat_target_to_user(t, dstptr, size);
1690         if (ret)
1691                 return ret;
1692         next_offset = e->next_offset - (origsize - *size);
1693
1694         if (put_user(watchers_offset, &ce->watchers_offset) ||
1695             put_user(target_offset, &ce->target_offset) ||
1696             put_user(next_offset, &ce->next_offset))
1697                 return -EFAULT;
1698
1699         *size -= sizeof(*ce);
1700         return 0;
1701 }
1702
1703 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1704 {
1705         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1706         *off += ebt_compat_entry_padsize();
1707         return 0;
1708 }
1709
1710 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1711 {
1712         *off += xt_compat_target_offset(w->u.watcher);
1713         *off += ebt_compat_entry_padsize();
1714         return 0;
1715 }
1716
1717 static int compat_calc_entry(const struct ebt_entry *e,
1718                              const struct ebt_table_info *info,
1719                              const void *base,
1720                              struct compat_ebt_replace *newinfo)
1721 {
1722         const struct ebt_entry_target *t;
1723         unsigned int entry_offset;
1724         int off, ret, i;
1725
1726         if (e->bitmask == 0)
1727                 return 0;
1728
1729         off = 0;
1730         entry_offset = (void *)e - base;
1731
1732         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1733         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1734
1735         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1736
1737         off += xt_compat_target_offset(t->u.target);
1738         off += ebt_compat_entry_padsize();
1739
1740         newinfo->entries_size -= off;
1741
1742         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1743         if (ret)
1744                 return ret;
1745
1746         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1747                 const void *hookptr = info->hook_entry[i];
1748                 if (info->hook_entry[i] &&
1749                     (e < (struct ebt_entry *)(base - hookptr))) {
1750                         newinfo->hook_entry[i] -= off;
1751                         pr_debug("0x%08X -> 0x%08X\n",
1752                                         newinfo->hook_entry[i] + off,
1753                                         newinfo->hook_entry[i]);
1754                 }
1755         }
1756
1757         return 0;
1758 }
1759
1760
1761 static int compat_table_info(const struct ebt_table_info *info,
1762                              struct compat_ebt_replace *newinfo)
1763 {
1764         unsigned int size = info->entries_size;
1765         const void *entries = info->entries;
1766
1767         newinfo->entries_size = size;
1768
1769         xt_compat_init_offsets(AF_INET, info->nentries);
1770         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1771                                                         entries, newinfo);
1772 }
1773
1774 static int compat_copy_everything_to_user(struct ebt_table *t,
1775                                           void __user *user, int *len, int cmd)
1776 {
1777         struct compat_ebt_replace repl, tmp;
1778         struct ebt_counter *oldcounters;
1779         struct ebt_table_info tinfo;
1780         int ret;
1781         void __user *pos;
1782
1783         memset(&tinfo, 0, sizeof(tinfo));
1784
1785         if (cmd == EBT_SO_GET_ENTRIES) {
1786                 tinfo.entries_size = t->private->entries_size;
1787                 tinfo.nentries = t->private->nentries;
1788                 tinfo.entries = t->private->entries;
1789                 oldcounters = t->private->counters;
1790         } else {
1791                 tinfo.entries_size = t->table->entries_size;
1792                 tinfo.nentries = t->table->nentries;
1793                 tinfo.entries = t->table->entries;
1794                 oldcounters = t->table->counters;
1795         }
1796
1797         if (copy_from_user(&tmp, user, sizeof(tmp)))
1798                 return -EFAULT;
1799
1800         if (tmp.nentries != tinfo.nentries ||
1801            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1802                 return -EINVAL;
1803
1804         memcpy(&repl, &tmp, sizeof(repl));
1805         if (cmd == EBT_SO_GET_ENTRIES)
1806                 ret = compat_table_info(t->private, &repl);
1807         else
1808                 ret = compat_table_info(&tinfo, &repl);
1809         if (ret)
1810                 return ret;
1811
1812         if (*len != sizeof(tmp) + repl.entries_size +
1813            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1814                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1815                                 *len, tinfo.entries_size, repl.entries_size);
1816                 return -EINVAL;
1817         }
1818
1819         /* userspace might not need the counters */
1820         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1821                                         tmp.num_counters, tinfo.nentries);
1822         if (ret)
1823                 return ret;
1824
1825         pos = compat_ptr(tmp.entries);
1826         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1827                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1828 }
1829
1830 struct ebt_entries_buf_state {
1831         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1832         u32 buf_kern_len;       /* total size of kernel buffer */
1833         u32 buf_kern_offset;    /* amount of data copied so far */
1834         u32 buf_user_offset;    /* read position in userspace buffer */
1835 };
1836
1837 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1838 {
1839         state->buf_kern_offset += sz;
1840         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1841 }
1842
1843 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1844                        void *data, unsigned int sz)
1845 {
1846         if (state->buf_kern_start == NULL)
1847                 goto count_only;
1848
1849         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1850
1851         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1852
1853  count_only:
1854         state->buf_user_offset += sz;
1855         return ebt_buf_count(state, sz);
1856 }
1857
1858 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1859 {
1860         char *b = state->buf_kern_start;
1861
1862         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1863
1864         if (b != NULL && sz > 0)
1865                 memset(b + state->buf_kern_offset, 0, sz);
1866         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1867         return ebt_buf_count(state, sz);
1868 }
1869
1870 enum compat_mwt {
1871         EBT_COMPAT_MATCH,
1872         EBT_COMPAT_WATCHER,
1873         EBT_COMPAT_TARGET,
1874 };
1875
1876 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1877                                 enum compat_mwt compat_mwt,
1878                                 struct ebt_entries_buf_state *state,
1879                                 const unsigned char *base)
1880 {
1881         char name[EBT_FUNCTION_MAXNAMELEN];
1882         struct xt_match *match;
1883         struct xt_target *wt;
1884         void *dst = NULL;
1885         int off, pad = 0, ret = 0;
1886         unsigned int size_kern, entry_offset, match_size = mwt->match_size;
1887
1888         strlcpy(name, mwt->u.name, sizeof(name));
1889
1890         if (state->buf_kern_start)
1891                 dst = state->buf_kern_start + state->buf_kern_offset;
1892
1893         entry_offset = (unsigned char *) mwt - base;
1894         switch (compat_mwt) {
1895         case EBT_COMPAT_MATCH:
1896                 match = try_then_request_module(xt_find_match(NFPROTO_BRIDGE,
1897                                                 name, 0), "ebt_%s", name);
1898                 if (match == NULL)
1899                         return -ENOENT;
1900                 if (IS_ERR(match))
1901                         return PTR_ERR(match);
1902
1903                 off = ebt_compat_match_offset(match, match_size);
1904                 if (dst) {
1905                         if (match->compat_from_user)
1906                                 match->compat_from_user(dst, mwt->data);
1907                         else
1908                                 memcpy(dst, mwt->data, match_size);
1909                 }
1910
1911                 size_kern = match->matchsize;
1912                 if (unlikely(size_kern == -1))
1913                         size_kern = match_size;
1914                 module_put(match->me);
1915                 break;
1916         case EBT_COMPAT_WATCHER: /* fallthrough */
1917         case EBT_COMPAT_TARGET:
1918                 wt = try_then_request_module(xt_find_target(NFPROTO_BRIDGE,
1919                                                 name, 0), "ebt_%s", name);
1920                 if (wt == NULL)
1921                         return -ENOENT;
1922                 if (IS_ERR(wt))
1923                         return PTR_ERR(wt);
1924                 off = xt_compat_target_offset(wt);
1925
1926                 if (dst) {
1927                         if (wt->compat_from_user)
1928                                 wt->compat_from_user(dst, mwt->data);
1929                         else
1930                                 memcpy(dst, mwt->data, match_size);
1931                 }
1932
1933                 size_kern = wt->targetsize;
1934                 module_put(wt->me);
1935                 break;
1936         }
1937
1938         if (!dst) {
1939                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset,
1940                                         off + ebt_compat_entry_padsize());
1941                 if (ret < 0)
1942                         return ret;
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 #define EBT_COMPAT_WATCHER_ITERATE(e, fn, args...)          \
2020 ({                                                          \
2021         unsigned int __i;                                   \
2022         int __ret = 0;                                      \
2023         struct compat_ebt_entry_mwt *__watcher;             \
2024                                                             \
2025         for (__i = e->watchers_offset;                      \
2026              __i < (e)->target_offset;                      \
2027              __i += __watcher->watcher_size +               \
2028              sizeof(struct compat_ebt_entry_mwt)) {         \
2029                 __watcher = (void *)(e) + __i;              \
2030                 __ret = fn(__watcher , ## args);            \
2031                 if (__ret != 0)                             \
2032                         break;                              \
2033         }                                                   \
2034         if (__ret == 0) {                                   \
2035                 if (__i != (e)->target_offset)              \
2036                         __ret = -EINVAL;                    \
2037         }                                                   \
2038         __ret;                                              \
2039 })
2040
2041 #define EBT_COMPAT_MATCH_ITERATE(e, fn, args...)            \
2042 ({                                                          \
2043         unsigned int __i;                                   \
2044         int __ret = 0;                                      \
2045         struct compat_ebt_entry_mwt *__match;               \
2046                                                             \
2047         for (__i = sizeof(struct ebt_entry);                \
2048              __i < (e)->watchers_offset;                    \
2049              __i += __match->match_size +                   \
2050              sizeof(struct compat_ebt_entry_mwt)) {         \
2051                 __match = (void *)(e) + __i;                \
2052                 __ret = fn(__match , ## args);              \
2053                 if (__ret != 0)                             \
2054                         break;                              \
2055         }                                                   \
2056         if (__ret == 0) {                                   \
2057                 if (__i != (e)->watchers_offset)            \
2058                         __ret = -EINVAL;                    \
2059         }                                                   \
2060         __ret;                                              \
2061 })
2062
2063 /* called for all ebt_entry structures. */
2064 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2065                           unsigned int *total,
2066                           struct ebt_entries_buf_state *state)
2067 {
2068         unsigned int i, j, startoff, new_offset = 0;
2069         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2070         unsigned int offsets[4];
2071         unsigned int *offsets_update = NULL;
2072         int ret;
2073         char *buf_start;
2074
2075         if (*total < sizeof(struct ebt_entries))
2076                 return -EINVAL;
2077
2078         if (!entry->bitmask) {
2079                 *total -= sizeof(struct ebt_entries);
2080                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2081         }
2082         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2083                 return -EINVAL;
2084
2085         startoff = state->buf_user_offset;
2086         /* pull in most part of ebt_entry, it does not need to be changed. */
2087         ret = ebt_buf_add(state, entry,
2088                         offsetof(struct ebt_entry, watchers_offset));
2089         if (ret < 0)
2090                 return ret;
2091
2092         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2093         memcpy(&offsets[1], &entry->watchers_offset,
2094                         sizeof(offsets) - sizeof(offsets[0]));
2095
2096         if (state->buf_kern_start) {
2097                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2098                 offsets_update = (unsigned int *) buf_start;
2099         }
2100         ret = ebt_buf_add(state, &offsets[1],
2101                         sizeof(offsets) - sizeof(offsets[0]));
2102         if (ret < 0)
2103                 return ret;
2104         buf_start = (char *) entry;
2105         /*
2106          * 0: matches offset, always follows ebt_entry.
2107          * 1: watchers offset, from ebt_entry structure
2108          * 2: target offset, from ebt_entry structure
2109          * 3: next ebt_entry offset, from ebt_entry structure
2110          *
2111          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2112          */
2113         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2114                 struct compat_ebt_entry_mwt *match32;
2115                 unsigned int size;
2116                 char *buf = buf_start;
2117
2118                 buf = buf_start + offsets[i];
2119                 if (offsets[i] > offsets[j])
2120                         return -EINVAL;
2121
2122                 match32 = (struct compat_ebt_entry_mwt *) buf;
2123                 size = offsets[j] - offsets[i];
2124                 ret = ebt_size_mwt(match32, size, i, state, base);
2125                 if (ret < 0)
2126                         return ret;
2127                 new_offset += ret;
2128                 if (offsets_update && new_offset) {
2129                         pr_debug("change offset %d to %d\n",
2130                                 offsets_update[i], offsets[j] + new_offset);
2131                         offsets_update[i] = offsets[j] + new_offset;
2132                 }
2133         }
2134
2135         startoff = state->buf_user_offset - startoff;
2136
2137         BUG_ON(*total < startoff);
2138         *total -= startoff;
2139         return 0;
2140 }
2141
2142 /*
2143  * repl->entries_size is the size of the ebt_entry blob in userspace.
2144  * It might need more memory when copied to a 64 bit kernel in case
2145  * userspace is 32-bit. So, first task: find out how much memory is needed.
2146  *
2147  * Called before validation is performed.
2148  */
2149 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2150                                 struct ebt_entries_buf_state *state)
2151 {
2152         unsigned int size_remaining = size_user;
2153         int ret;
2154
2155         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2156                                         &size_remaining, state);
2157         if (ret < 0)
2158                 return ret;
2159
2160         WARN_ON(size_remaining);
2161         return state->buf_kern_offset;
2162 }
2163
2164
2165 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2166                                             void __user *user, unsigned int len)
2167 {
2168         struct compat_ebt_replace tmp;
2169         int i;
2170
2171         if (len < sizeof(tmp))
2172                 return -EINVAL;
2173
2174         if (copy_from_user(&tmp, user, sizeof(tmp)))
2175                 return -EFAULT;
2176
2177         if (len != sizeof(tmp) + tmp.entries_size)
2178                 return -EINVAL;
2179
2180         if (tmp.entries_size == 0)
2181                 return -EINVAL;
2182
2183         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2184                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2185                 return -ENOMEM;
2186         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2187                 return -ENOMEM;
2188
2189         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2190
2191         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2192         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2193                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2194
2195         repl->num_counters = tmp.num_counters;
2196         repl->counters = compat_ptr(tmp.counters);
2197         repl->entries = compat_ptr(tmp.entries);
2198         return 0;
2199 }
2200
2201 static int compat_do_replace(struct net *net, void __user *user,
2202                              unsigned int len)
2203 {
2204         int ret, i, countersize, size64;
2205         struct ebt_table_info *newinfo;
2206         struct ebt_replace tmp;
2207         struct ebt_entries_buf_state state;
2208         void *entries_tmp;
2209
2210         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2211         if (ret) {
2212                 /* try real handler in case userland supplied needed padding */
2213                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2214                         ret = 0;
2215                 return ret;
2216         }
2217
2218         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2219         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2220         if (!newinfo)
2221                 return -ENOMEM;
2222
2223         if (countersize)
2224                 memset(newinfo->counters, 0, countersize);
2225
2226         memset(&state, 0, sizeof(state));
2227
2228         newinfo->entries = vmalloc(tmp.entries_size);
2229         if (!newinfo->entries) {
2230                 ret = -ENOMEM;
2231                 goto free_newinfo;
2232         }
2233         if (copy_from_user(
2234            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2235                 ret = -EFAULT;
2236                 goto free_entries;
2237         }
2238
2239         entries_tmp = newinfo->entries;
2240
2241         xt_compat_lock(NFPROTO_BRIDGE);
2242
2243         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2244         if (ret < 0)
2245                 goto out_unlock;
2246
2247         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2248                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2249                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2250
2251         size64 = ret;
2252         newinfo->entries = vmalloc(size64);
2253         if (!newinfo->entries) {
2254                 vfree(entries_tmp);
2255                 ret = -ENOMEM;
2256                 goto out_unlock;
2257         }
2258
2259         memset(&state, 0, sizeof(state));
2260         state.buf_kern_start = newinfo->entries;
2261         state.buf_kern_len = size64;
2262
2263         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2264         BUG_ON(ret < 0);        /* parses same data again */
2265
2266         vfree(entries_tmp);
2267         tmp.entries_size = size64;
2268
2269         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2270                 char __user *usrptr;
2271                 if (tmp.hook_entry[i]) {
2272                         unsigned int delta;
2273                         usrptr = (char __user *) tmp.hook_entry[i];
2274                         delta = usrptr - tmp.entries;
2275                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2276                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2277                 }
2278         }
2279
2280         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2281         xt_compat_unlock(NFPROTO_BRIDGE);
2282
2283         ret = do_replace_finish(net, &tmp, newinfo);
2284         if (ret == 0)
2285                 return ret;
2286 free_entries:
2287         vfree(newinfo->entries);
2288 free_newinfo:
2289         vfree(newinfo);
2290         return ret;
2291 out_unlock:
2292         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2293         xt_compat_unlock(NFPROTO_BRIDGE);
2294         goto free_entries;
2295 }
2296
2297 static int compat_update_counters(struct net *net, void __user *user,
2298                                   unsigned int len)
2299 {
2300         struct compat_ebt_replace hlp;
2301
2302         if (copy_from_user(&hlp, user, sizeof(hlp)))
2303                 return -EFAULT;
2304
2305         /* try real handler in case userland supplied needed padding */
2306         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2307                 return update_counters(net, user, len);
2308
2309         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2310                                         hlp.num_counters, user, len);
2311 }
2312
2313 static int compat_do_ebt_set_ctl(struct sock *sk,
2314                 int cmd, void __user *user, unsigned int len)
2315 {
2316         int ret;
2317
2318         if (!capable(CAP_NET_ADMIN))
2319                 return -EPERM;
2320
2321         switch (cmd) {
2322         case EBT_SO_SET_ENTRIES:
2323                 ret = compat_do_replace(sock_net(sk), user, len);
2324                 break;
2325         case EBT_SO_SET_COUNTERS:
2326                 ret = compat_update_counters(sock_net(sk), user, len);
2327                 break;
2328         default:
2329                 ret = -EINVAL;
2330   }
2331         return ret;
2332 }
2333
2334 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2335                 void __user *user, int *len)
2336 {
2337         int ret;
2338         struct compat_ebt_replace tmp;
2339         struct ebt_table *t;
2340
2341         if (!capable(CAP_NET_ADMIN))
2342                 return -EPERM;
2343
2344         /* try real handler in case userland supplied needed padding */
2345         if ((cmd == EBT_SO_GET_INFO ||
2346              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2347                         return do_ebt_get_ctl(sk, cmd, user, len);
2348
2349         if (copy_from_user(&tmp, user, sizeof(tmp)))
2350                 return -EFAULT;
2351
2352         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
2353         if (!t)
2354                 return ret;
2355
2356         xt_compat_lock(NFPROTO_BRIDGE);
2357         switch (cmd) {
2358         case EBT_SO_GET_INFO:
2359                 tmp.nentries = t->private->nentries;
2360                 ret = compat_table_info(t->private, &tmp);
2361                 if (ret)
2362                         goto out;
2363                 tmp.valid_hooks = t->valid_hooks;
2364
2365                 if (copy_to_user(user, &tmp, *len) != 0) {
2366                         ret = -EFAULT;
2367                         break;
2368                 }
2369                 ret = 0;
2370                 break;
2371         case EBT_SO_GET_INIT_INFO:
2372                 tmp.nentries = t->table->nentries;
2373                 tmp.entries_size = t->table->entries_size;
2374                 tmp.valid_hooks = t->table->valid_hooks;
2375
2376                 if (copy_to_user(user, &tmp, *len) != 0) {
2377                         ret = -EFAULT;
2378                         break;
2379                 }
2380                 ret = 0;
2381                 break;
2382         case EBT_SO_GET_ENTRIES:
2383         case EBT_SO_GET_INIT_ENTRIES:
2384                 /*
2385                  * try real handler first in case of userland-side padding.
2386                  * in case we are dealing with an 'ordinary' 32 bit binary
2387                  * without 64bit compatibility padding, this will fail right
2388                  * after copy_from_user when the *len argument is validated.
2389                  *
2390                  * the compat_ variant needs to do one pass over the kernel
2391                  * data set to adjust for size differences before it the check.
2392                  */
2393                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2394                         ret = 0;
2395                 else
2396                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2397                 break;
2398         default:
2399                 ret = -EINVAL;
2400         }
2401  out:
2402         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2403         xt_compat_unlock(NFPROTO_BRIDGE);
2404         mutex_unlock(&ebt_mutex);
2405         return ret;
2406 }
2407 #endif
2408
2409 static struct nf_sockopt_ops ebt_sockopts =
2410 {
2411         .pf             = PF_INET,
2412         .set_optmin     = EBT_BASE_CTL,
2413         .set_optmax     = EBT_SO_SET_MAX + 1,
2414         .set            = do_ebt_set_ctl,
2415 #ifdef CONFIG_COMPAT
2416         .compat_set     = compat_do_ebt_set_ctl,
2417 #endif
2418         .get_optmin     = EBT_BASE_CTL,
2419         .get_optmax     = EBT_SO_GET_MAX + 1,
2420         .get            = do_ebt_get_ctl,
2421 #ifdef CONFIG_COMPAT
2422         .compat_get     = compat_do_ebt_get_ctl,
2423 #endif
2424         .owner          = THIS_MODULE,
2425 };
2426
2427 static int __init ebtables_init(void)
2428 {
2429         int ret;
2430
2431         ret = xt_register_target(&ebt_standard_target);
2432         if (ret < 0)
2433                 return ret;
2434         ret = nf_register_sockopt(&ebt_sockopts);
2435         if (ret < 0) {
2436                 xt_unregister_target(&ebt_standard_target);
2437                 return ret;
2438         }
2439
2440         printk(KERN_INFO "Ebtables v2.0 registered\n");
2441         return 0;
2442 }
2443
2444 static void __exit ebtables_fini(void)
2445 {
2446         nf_unregister_sockopt(&ebt_sockopts);
2447         xt_unregister_target(&ebt_standard_target);
2448         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2449 }
2450
2451 EXPORT_SYMBOL(ebt_register_table);
2452 EXPORT_SYMBOL(ebt_unregister_table);
2453 EXPORT_SYMBOL(ebt_do_table);
2454 module_init(ebtables_init);
2455 module_exit(ebtables_fini);
2456 MODULE_LICENSE("GPL");