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(NFPROTO_BRIDGE, 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;
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         state->buf_kern_offset += match_size + off;
1939         state->buf_user_offset += match_size;
1940         pad = XT_ALIGN(size_kern) - size_kern;
1941
1942         if (pad > 0 && dst) {
1943                 BUG_ON(state->buf_kern_len <= pad);
1944                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1945                 memset(dst + size_kern, 0, pad);
1946         }
1947         return off + match_size;
1948 }
1949
1950 /*
1951  * return size of all matches, watchers or target, including necessary
1952  * alignment and padding.
1953  */
1954 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1955                         unsigned int size_left, enum compat_mwt type,
1956                         struct ebt_entries_buf_state *state, const void *base)
1957 {
1958         int growth = 0;
1959         char *buf;
1960
1961         if (size_left == 0)
1962                 return 0;
1963
1964         buf = (char *) match32;
1965
1966         while (size_left >= sizeof(*match32)) {
1967                 struct ebt_entry_match *match_kern;
1968                 int ret;
1969
1970                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1971                 if (match_kern) {
1972                         char *tmp;
1973                         tmp = state->buf_kern_start + state->buf_kern_offset;
1974                         match_kern = (struct ebt_entry_match *) tmp;
1975                 }
1976                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1977                 if (ret < 0)
1978                         return ret;
1979                 size_left -= sizeof(*match32);
1980
1981                 /* add padding before match->data (if any) */
1982                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1983                 if (ret < 0)
1984                         return ret;
1985
1986                 if (match32->match_size > size_left)
1987                         return -EINVAL;
1988
1989                 size_left -= match32->match_size;
1990
1991                 ret = compat_mtw_from_user(match32, type, state, base);
1992                 if (ret < 0)
1993                         return ret;
1994
1995                 BUG_ON(ret < match32->match_size);
1996                 growth += ret - match32->match_size;
1997                 growth += ebt_compat_entry_padsize();
1998
1999                 buf += sizeof(*match32);
2000                 buf += match32->match_size;
2001
2002                 if (match_kern)
2003                         match_kern->match_size = ret;
2004
2005                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2006                 match32 = (struct compat_ebt_entry_mwt *) buf;
2007         }
2008
2009         return growth;
2010 }
2011
2012 /* called for all ebt_entry structures. */
2013 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2014                           unsigned int *total,
2015                           struct ebt_entries_buf_state *state)
2016 {
2017         unsigned int i, j, startoff, new_offset = 0;
2018         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2019         unsigned int offsets[4];
2020         unsigned int *offsets_update = NULL;
2021         int ret;
2022         char *buf_start;
2023
2024         if (*total < sizeof(struct ebt_entries))
2025                 return -EINVAL;
2026
2027         if (!entry->bitmask) {
2028                 *total -= sizeof(struct ebt_entries);
2029                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2030         }
2031         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2032                 return -EINVAL;
2033
2034         startoff = state->buf_user_offset;
2035         /* pull in most part of ebt_entry, it does not need to be changed. */
2036         ret = ebt_buf_add(state, entry,
2037                         offsetof(struct ebt_entry, watchers_offset));
2038         if (ret < 0)
2039                 return ret;
2040
2041         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2042         memcpy(&offsets[1], &entry->watchers_offset,
2043                         sizeof(offsets) - sizeof(offsets[0]));
2044
2045         if (state->buf_kern_start) {
2046                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2047                 offsets_update = (unsigned int *) buf_start;
2048         }
2049         ret = ebt_buf_add(state, &offsets[1],
2050                         sizeof(offsets) - sizeof(offsets[0]));
2051         if (ret < 0)
2052                 return ret;
2053         buf_start = (char *) entry;
2054         /*
2055          * 0: matches offset, always follows ebt_entry.
2056          * 1: watchers offset, from ebt_entry structure
2057          * 2: target offset, from ebt_entry structure
2058          * 3: next ebt_entry offset, from ebt_entry structure
2059          *
2060          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2061          */
2062         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2063                 struct compat_ebt_entry_mwt *match32;
2064                 unsigned int size;
2065                 char *buf = buf_start;
2066
2067                 buf = buf_start + offsets[i];
2068                 if (offsets[i] > offsets[j])
2069                         return -EINVAL;
2070
2071                 match32 = (struct compat_ebt_entry_mwt *) buf;
2072                 size = offsets[j] - offsets[i];
2073                 ret = ebt_size_mwt(match32, size, i, state, base);
2074                 if (ret < 0)
2075                         return ret;
2076                 new_offset += ret;
2077                 if (offsets_update && new_offset) {
2078                         pr_debug("change offset %d to %d\n",
2079                                 offsets_update[i], offsets[j] + new_offset);
2080                         offsets_update[i] = offsets[j] + new_offset;
2081                 }
2082         }
2083
2084         if (state->buf_kern_start == NULL) {
2085                 unsigned int offset = buf_start - (char *) base;
2086
2087                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2088                 if (ret < 0)
2089                         return ret;
2090         }
2091
2092         startoff = state->buf_user_offset - startoff;
2093
2094         BUG_ON(*total < startoff);
2095         *total -= startoff;
2096         return 0;
2097 }
2098
2099 /*
2100  * repl->entries_size is the size of the ebt_entry blob in userspace.
2101  * It might need more memory when copied to a 64 bit kernel in case
2102  * userspace is 32-bit. So, first task: find out how much memory is needed.
2103  *
2104  * Called before validation is performed.
2105  */
2106 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2107                                 struct ebt_entries_buf_state *state)
2108 {
2109         unsigned int size_remaining = size_user;
2110         int ret;
2111
2112         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2113                                         &size_remaining, state);
2114         if (ret < 0)
2115                 return ret;
2116
2117         WARN_ON(size_remaining);
2118         return state->buf_kern_offset;
2119 }
2120
2121
2122 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2123                                             void __user *user, unsigned int len)
2124 {
2125         struct compat_ebt_replace tmp;
2126         int i;
2127
2128         if (len < sizeof(tmp))
2129                 return -EINVAL;
2130
2131         if (copy_from_user(&tmp, user, sizeof(tmp)))
2132                 return -EFAULT;
2133
2134         if (len != sizeof(tmp) + tmp.entries_size)
2135                 return -EINVAL;
2136
2137         if (tmp.entries_size == 0)
2138                 return -EINVAL;
2139
2140         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2141                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2142                 return -ENOMEM;
2143         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2144                 return -ENOMEM;
2145
2146         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2147
2148         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2149         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2150                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2151
2152         repl->num_counters = tmp.num_counters;
2153         repl->counters = compat_ptr(tmp.counters);
2154         repl->entries = compat_ptr(tmp.entries);
2155         return 0;
2156 }
2157
2158 static int compat_do_replace(struct net *net, void __user *user,
2159                              unsigned int len)
2160 {
2161         int ret, i, countersize, size64;
2162         struct ebt_table_info *newinfo;
2163         struct ebt_replace tmp;
2164         struct ebt_entries_buf_state state;
2165         void *entries_tmp;
2166
2167         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2168         if (ret) {
2169                 /* try real handler in case userland supplied needed padding */
2170                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2171                         ret = 0;
2172                 return ret;
2173         }
2174
2175         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2176         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2177         if (!newinfo)
2178                 return -ENOMEM;
2179
2180         if (countersize)
2181                 memset(newinfo->counters, 0, countersize);
2182
2183         memset(&state, 0, sizeof(state));
2184
2185         newinfo->entries = vmalloc(tmp.entries_size);
2186         if (!newinfo->entries) {
2187                 ret = -ENOMEM;
2188                 goto free_newinfo;
2189         }
2190         if (copy_from_user(
2191            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2192                 ret = -EFAULT;
2193                 goto free_entries;
2194         }
2195
2196         entries_tmp = newinfo->entries;
2197
2198         xt_compat_lock(NFPROTO_BRIDGE);
2199
2200         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2201         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2202         if (ret < 0)
2203                 goto out_unlock;
2204
2205         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2206                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2207                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2208
2209         size64 = ret;
2210         newinfo->entries = vmalloc(size64);
2211         if (!newinfo->entries) {
2212                 vfree(entries_tmp);
2213                 ret = -ENOMEM;
2214                 goto out_unlock;
2215         }
2216
2217         memset(&state, 0, sizeof(state));
2218         state.buf_kern_start = newinfo->entries;
2219         state.buf_kern_len = size64;
2220
2221         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2222         BUG_ON(ret < 0);        /* parses same data again */
2223
2224         vfree(entries_tmp);
2225         tmp.entries_size = size64;
2226
2227         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2228                 char __user *usrptr;
2229                 if (tmp.hook_entry[i]) {
2230                         unsigned int delta;
2231                         usrptr = (char __user *) tmp.hook_entry[i];
2232                         delta = usrptr - tmp.entries;
2233                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2234                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2235                 }
2236         }
2237
2238         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2239         xt_compat_unlock(NFPROTO_BRIDGE);
2240
2241         ret = do_replace_finish(net, &tmp, newinfo);
2242         if (ret == 0)
2243                 return ret;
2244 free_entries:
2245         vfree(newinfo->entries);
2246 free_newinfo:
2247         vfree(newinfo);
2248         return ret;
2249 out_unlock:
2250         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2251         xt_compat_unlock(NFPROTO_BRIDGE);
2252         goto free_entries;
2253 }
2254
2255 static int compat_update_counters(struct net *net, void __user *user,
2256                                   unsigned int len)
2257 {
2258         struct compat_ebt_replace hlp;
2259
2260         if (copy_from_user(&hlp, user, sizeof(hlp)))
2261                 return -EFAULT;
2262
2263         /* try real handler in case userland supplied needed padding */
2264         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2265                 return update_counters(net, user, len);
2266
2267         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2268                                         hlp.num_counters, user, len);
2269 }
2270
2271 static int compat_do_ebt_set_ctl(struct sock *sk,
2272                 int cmd, void __user *user, unsigned int len)
2273 {
2274         int ret;
2275
2276         if (!capable(CAP_NET_ADMIN))
2277                 return -EPERM;
2278
2279         switch (cmd) {
2280         case EBT_SO_SET_ENTRIES:
2281                 ret = compat_do_replace(sock_net(sk), user, len);
2282                 break;
2283         case EBT_SO_SET_COUNTERS:
2284                 ret = compat_update_counters(sock_net(sk), user, len);
2285                 break;
2286         default:
2287                 ret = -EINVAL;
2288   }
2289         return ret;
2290 }
2291
2292 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2293                 void __user *user, int *len)
2294 {
2295         int ret;
2296         struct compat_ebt_replace tmp;
2297         struct ebt_table *t;
2298
2299         if (!capable(CAP_NET_ADMIN))
2300                 return -EPERM;
2301
2302         /* try real handler in case userland supplied needed padding */
2303         if ((cmd == EBT_SO_GET_INFO ||
2304              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2305                         return do_ebt_get_ctl(sk, cmd, user, len);
2306
2307         if (copy_from_user(&tmp, user, sizeof(tmp)))
2308                 return -EFAULT;
2309
2310         t = find_table_lock(sock_net(sk), tmp.name, &ret, &ebt_mutex);
2311         if (!t)
2312                 return ret;
2313
2314         xt_compat_lock(NFPROTO_BRIDGE);
2315         switch (cmd) {
2316         case EBT_SO_GET_INFO:
2317                 tmp.nentries = t->private->nentries;
2318                 ret = compat_table_info(t->private, &tmp);
2319                 if (ret)
2320                         goto out;
2321                 tmp.valid_hooks = t->valid_hooks;
2322
2323                 if (copy_to_user(user, &tmp, *len) != 0) {
2324                         ret = -EFAULT;
2325                         break;
2326                 }
2327                 ret = 0;
2328                 break;
2329         case EBT_SO_GET_INIT_INFO:
2330                 tmp.nentries = t->table->nentries;
2331                 tmp.entries_size = t->table->entries_size;
2332                 tmp.valid_hooks = t->table->valid_hooks;
2333
2334                 if (copy_to_user(user, &tmp, *len) != 0) {
2335                         ret = -EFAULT;
2336                         break;
2337                 }
2338                 ret = 0;
2339                 break;
2340         case EBT_SO_GET_ENTRIES:
2341         case EBT_SO_GET_INIT_ENTRIES:
2342                 /*
2343                  * try real handler first in case of userland-side padding.
2344                  * in case we are dealing with an 'ordinary' 32 bit binary
2345                  * without 64bit compatibility padding, this will fail right
2346                  * after copy_from_user when the *len argument is validated.
2347                  *
2348                  * the compat_ variant needs to do one pass over the kernel
2349                  * data set to adjust for size differences before it the check.
2350                  */
2351                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2352                         ret = 0;
2353                 else
2354                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2355                 break;
2356         default:
2357                 ret = -EINVAL;
2358         }
2359  out:
2360         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2361         xt_compat_unlock(NFPROTO_BRIDGE);
2362         mutex_unlock(&ebt_mutex);
2363         return ret;
2364 }
2365 #endif
2366
2367 static struct nf_sockopt_ops ebt_sockopts =
2368 {
2369         .pf             = PF_INET,
2370         .set_optmin     = EBT_BASE_CTL,
2371         .set_optmax     = EBT_SO_SET_MAX + 1,
2372         .set            = do_ebt_set_ctl,
2373 #ifdef CONFIG_COMPAT
2374         .compat_set     = compat_do_ebt_set_ctl,
2375 #endif
2376         .get_optmin     = EBT_BASE_CTL,
2377         .get_optmax     = EBT_SO_GET_MAX + 1,
2378         .get            = do_ebt_get_ctl,
2379 #ifdef CONFIG_COMPAT
2380         .compat_get     = compat_do_ebt_get_ctl,
2381 #endif
2382         .owner          = THIS_MODULE,
2383 };
2384
2385 static int __init ebtables_init(void)
2386 {
2387         int ret;
2388
2389         ret = xt_register_target(&ebt_standard_target);
2390         if (ret < 0)
2391                 return ret;
2392         ret = nf_register_sockopt(&ebt_sockopts);
2393         if (ret < 0) {
2394                 xt_unregister_target(&ebt_standard_target);
2395                 return ret;
2396         }
2397
2398         printk(KERN_INFO "Ebtables v2.0 registered\n");
2399         return 0;
2400 }
2401
2402 static void __exit ebtables_fini(void)
2403 {
2404         nf_unregister_sockopt(&ebt_sockopts);
2405         xt_unregister_target(&ebt_standard_target);
2406         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2407 }
2408
2409 EXPORT_SYMBOL(ebt_register_table);
2410 EXPORT_SYMBOL(ebt_unregister_table);
2411 EXPORT_SYMBOL(ebt_do_table);
2412 module_init(ebtables_init);
2413 module_exit(ebtables_fini);
2414 MODULE_LICENSE("GPL");