net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is strongly inspired by the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  37
  38 /* Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48                                  COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_action_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 /* Do some firewalling */
 181 unsigned int ebt_do_table(struct sk_buff *skb,
 182                           const struct nf_hook_state *state,
 183                           struct ebt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         int i, nentries;
 187         struct ebt_entry *point;
 188         struct ebt_counter *counter_base, *cb_base;
 189         const struct ebt_entry_target *t;
 190         int verdict, sp = 0;
 191         struct ebt_chainstack *cs;
 192         struct ebt_entries *chaininfo;
 193         const char *base;
 194         const struct ebt_table_info *private;
 195         struct xt_action_param acpar;
 196
 197         acpar.state   = state;
 198         acpar.hotdrop = false;
 199
 200         read_lock_bh(&table->lock);
 201         private = table->private;
 202         cb_base = COUNTER_BASE(private->counters, private->nentries,
 203            smp_processor_id());
 204         if (private->chainstack)
 205                 cs = private->chainstack[smp_processor_id()];
 206         else
 207                 cs = NULL;
 208         chaininfo = private->hook_entry[hook];
 209         nentries = private->hook_entry[hook]->nentries;
 210         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 211         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 212         /* base for chain jumps */
 213         base = private->entries;
 214         i = 0;
 215         while (i < nentries) {
 216                 if (ebt_basic_match(point, skb, state->in, state->out))
 217                         goto letscontinue;
 218
 219                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 220                         goto letscontinue;
 221                 if (acpar.hotdrop) {
 222                         read_unlock_bh(&table->lock);
 223                         return NF_DROP;
 224                 }
 225
 226                 /* increase counter */
 227                 (*(counter_base + i)).pcnt++;
 228                 (*(counter_base + i)).bcnt += skb->len;
 229
 230                 /* these should only watch: not modify, nor tell us
 231                  * what to do with the packet
 232                  */
 233                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 234
 235                 t = (struct ebt_entry_target *)
 236                    (((char *)point) + point->target_offset);
 237                 /* standard target */
 238                 if (!t->u.target->target)
 239                         verdict = ((struct ebt_standard_target *)t)->verdict;
 240                 else {
 241                         acpar.target   = t->u.target;
 242                         acpar.targinfo = t->data;
 243                         verdict = t->u.target->target(skb, &acpar);
 244                 }
 245                 if (verdict == EBT_ACCEPT) {
 246                         read_unlock_bh(&table->lock);
 247                         return NF_ACCEPT;
 248                 }
 249                 if (verdict == EBT_DROP) {
 250                         read_unlock_bh(&table->lock);
 251                         return NF_DROP;
 252                 }
 253                 if (verdict == EBT_RETURN) {
 254 letsreturn:
 255 #ifdef CONFIG_NETFILTER_DEBUG
 256                         if (sp == 0) {
 257                                 BUGPRINT("RETURN on base chain");
 258                                 /* act like this is EBT_CONTINUE */
 259                                 goto letscontinue;
 260                         }
 261 #endif
 262                         sp--;
 263                         /* put all the local variables right */
 264                         i = cs[sp].n;
 265                         chaininfo = cs[sp].chaininfo;
 266                         nentries = chaininfo->nentries;
 267                         point = cs[sp].e;
 268                         counter_base = cb_base +
 269                            chaininfo->counter_offset;
 270                         continue;
 271                 }
 272                 if (verdict == EBT_CONTINUE)
 273                         goto letscontinue;
 274 #ifdef CONFIG_NETFILTER_DEBUG
 275                 if (verdict < 0) {
 276                         BUGPRINT("bogus standard verdict\n");
 277                         read_unlock_bh(&table->lock);
 278                         return NF_DROP;
 279                 }
 280 #endif
 281                 /* jump to a udc */
 282                 cs[sp].n = i + 1;
 283                 cs[sp].chaininfo = chaininfo;
 284                 cs[sp].e = ebt_next_entry(point);
 285                 i = 0;
 286                 chaininfo = (struct ebt_entries *) (base + verdict);
 287 #ifdef CONFIG_NETFILTER_DEBUG
 288                 if (chaininfo->distinguisher) {
 289                         BUGPRINT("jump to non-chain\n");
 290                         read_unlock_bh(&table->lock);
 291                         return NF_DROP;
 292                 }
 293 #endif
 294                 nentries = chaininfo->nentries;
 295                 point = (struct ebt_entry *)chaininfo->data;
 296                 counter_base = cb_base + chaininfo->counter_offset;
 297                 sp++;
 298                 continue;
 299 letscontinue:
 300                 point = ebt_next_entry(point);
 301                 i++;
 302         }
 303
 304         /* I actually like this :) */
 305         if (chaininfo->policy == EBT_RETURN)
 306                 goto letsreturn;
 307         if (chaininfo->policy == EBT_ACCEPT) {
 308                 read_unlock_bh(&table->lock);
 309                 return NF_ACCEPT;
 310         }
 311         read_unlock_bh(&table->lock);
 312         return NF_DROP;
 313 }
 314
 315 /* If it succeeds, returns element and locks mutex */
 316 static inline void *
 317 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 318                         struct mutex *mutex)
 319 {
 320         struct {
 321                 struct list_head list;
 322                 char name[EBT_FUNCTION_MAXNAMELEN];
 323         } *e;
 324
 325         mutex_lock(mutex);
 326         list_for_each_entry(e, head, list) {
 327                 if (strcmp(e->name, name) == 0)
 328                         return e;
 329         }
 330         *error = -ENOENT;
 331         mutex_unlock(mutex);
 332         return NULL;
 333 }
 334
 335 static void *
 336 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 337                  int *error, struct mutex *mutex)
 338 {
 339         return try_then_request_module(
 340                         find_inlist_lock_noload(head, name, error, mutex),
 341                         "%s%s", prefix, name);
 342 }
 343
 344 static inline struct ebt_table *
 345 find_table_lock(struct net *net, const char *name, int *error,
 346                 struct mutex *mutex)
 347 {
 348         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 349                                 "ebtable_", error, mutex);
 350 }
 351
 352 static inline int
 353 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 354                 unsigned int *cnt)
 355 {
 356         const struct ebt_entry *e = par->entryinfo;
 357         struct xt_match *match;
 358         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 359         int ret;
 360
 361         if (left < sizeof(struct ebt_entry_match) ||
 362             left - sizeof(struct ebt_entry_match) < m->match_size)
 363                 return -EINVAL;
 364
 365         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 366         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 367                 if (!IS_ERR(match))
 368                         module_put(match->me);
 369                 request_module("ebt_%s", m->u.name);
 370                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 371         }
 372         if (IS_ERR(match))
 373                 return PTR_ERR(match);
 374         m->u.match = match;
 375
 376         par->match     = match;
 377         par->matchinfo = m->data;
 378         ret = xt_check_match(par, m->match_size,
 379               e->ethproto, e->invflags & EBT_IPROTO);
 380         if (ret < 0) {
 381                 module_put(match->me);
 382                 return ret;
 383         }
 384
 385         (*cnt)++;
 386         return 0;
 387 }
 388
 389 static inline int
 390 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 391                   unsigned int *cnt)
 392 {
 393         const struct ebt_entry *e = par->entryinfo;
 394         struct xt_target *watcher;
 395         size_t left = ((char *)e + e->target_offset) - (char *)w;
 396         int ret;
 397
 398         if (left < sizeof(struct ebt_entry_watcher) ||
 399            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 400                 return -EINVAL;
 401
 402         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 403         if (IS_ERR(watcher))
 404                 return PTR_ERR(watcher);
 405         w->u.watcher = watcher;
 406
 407         par->target   = watcher;
 408         par->targinfo = w->data;
 409         ret = xt_check_target(par, w->watcher_size,
 410               e->ethproto, e->invflags & EBT_IPROTO);
 411         if (ret < 0) {
 412                 module_put(watcher->me);
 413                 return ret;
 414         }
 415
 416         (*cnt)++;
 417         return 0;
 418 }
 419
 420 static int ebt_verify_pointers(const struct ebt_replace *repl,
 421                                struct ebt_table_info *newinfo)
 422 {
 423         unsigned int limit = repl->entries_size;
 424         unsigned int valid_hooks = repl->valid_hooks;
 425         unsigned int offset = 0;
 426         int i;
 427
 428         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 429                 newinfo->hook_entry[i] = NULL;
 430
 431         newinfo->entries_size = repl->entries_size;
 432         newinfo->nentries = repl->nentries;
 433
 434         while (offset < limit) {
 435                 size_t left = limit - offset;
 436                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 437
 438                 if (left < sizeof(unsigned int))
 439                         break;
 440
 441                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 442                         if ((valid_hooks & (1 << i)) == 0)
 443                                 continue;
 444                         if ((char __user *)repl->hook_entry[i] ==
 445                              repl->entries + offset)
 446                                 break;
 447                 }
 448
 449                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 450                         if (e->bitmask != 0) {
 451                                 /* we make userspace set this right,
 452                                  * so there is no misunderstanding
 453                                  */
 454                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 455                                          "in distinguisher\n");
 456                                 return -EINVAL;
 457                         }
 458                         if (i != NF_BR_NUMHOOKS)
 459                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 460                         if (left < sizeof(struct ebt_entries))
 461                                 break;
 462                         offset += sizeof(struct ebt_entries);
 463                 } else {
 464                         if (left < sizeof(struct ebt_entry))
 465                                 break;
 466                         if (left < e->next_offset)
 467                                 break;
 468                         if (e->next_offset < sizeof(struct ebt_entry))
 469                                 return -EINVAL;
 470                         offset += e->next_offset;
 471                 }
 472         }
 473         if (offset != limit) {
 474                 BUGPRINT("entries_size too small\n");
 475                 return -EINVAL;
 476         }
 477
 478         /* check if all valid hooks have a chain */
 479         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 480                 if (!newinfo->hook_entry[i] &&
 481                    (valid_hooks & (1 << i))) {
 482                         BUGPRINT("Valid hook without chain\n");
 483                         return -EINVAL;
 484                 }
 485         }
 486         return 0;
 487 }
 488
 489 /* this one is very careful, as it is the first function
 490  * to parse the userspace data
 491  */
 492 static inline int
 493 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 494                                const struct ebt_table_info *newinfo,
 495                                unsigned int *n, unsigned int *cnt,
 496                                unsigned int *totalcnt, unsigned int *udc_cnt)
 497 {
 498         int i;
 499
 500         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 501                 if ((void *)e == (void *)newinfo->hook_entry[i])
 502                         break;
 503         }
 504         /* beginning of a new chain
 505          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 506          */
 507         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 508                 /* this checks if the previous chain has as many entries
 509                  * as it said it has
 510                  */
 511                 if (*n != *cnt) {
 512                         BUGPRINT("nentries does not equal the nr of entries "
 513                                  "in the chain\n");
 514                         return -EINVAL;
 515                 }
 516                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 517                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 518                         /* only RETURN from udc */
 519                         if (i != NF_BR_NUMHOOKS ||
 520                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 521                                 BUGPRINT("bad policy\n");
 522                                 return -EINVAL;
 523                         }
 524                 }
 525                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 526                         (*udc_cnt)++;
 527                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 528                         BUGPRINT("counter_offset != totalcnt");
 529                         return -EINVAL;
 530                 }
 531                 *n = ((struct ebt_entries *)e)->nentries;
 532                 *cnt = 0;
 533                 return 0;
 534         }
 535         /* a plain old entry, heh */
 536         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 537            e->watchers_offset > e->target_offset ||
 538            e->target_offset >= e->next_offset) {
 539                 BUGPRINT("entry offsets not in right order\n");
 540                 return -EINVAL;
 541         }
 542         /* this is not checked anywhere else */
 543         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 544                 BUGPRINT("target size too small\n");
 545                 return -EINVAL;
 546         }
 547         (*cnt)++;
 548         (*totalcnt)++;
 549         return 0;
 550 }
 551
 552 struct ebt_cl_stack {
 553         struct ebt_chainstack cs;
 554         int from;
 555         unsigned int hookmask;
 556 };
 557
 558 /* We need these positions to check that the jumps to a different part of the
 559  * entries is a jump to the beginning of a new chain.
 560  */
 561 static inline int
 562 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 563                       unsigned int *n, struct ebt_cl_stack *udc)
 564 {
 565         int i;
 566
 567         /* we're only interested in chain starts */
 568         if (e->bitmask)
 569                 return 0;
 570         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 571                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 572                         break;
 573         }
 574         /* only care about udc */
 575         if (i != NF_BR_NUMHOOKS)
 576                 return 0;
 577
 578         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 579         /* these initialisations are depended on later in check_chainloops() */
 580         udc[*n].cs.n = 0;
 581         udc[*n].hookmask = 0;
 582
 583         (*n)++;
 584         return 0;
 585 }
 586
 587 static inline int
 588 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 589 {
 590         struct xt_mtdtor_param par;
 591
 592         if (i && (*i)-- == 0)
 593                 return 1;
 594
 595         par.net       = net;
 596         par.match     = m->u.match;
 597         par.matchinfo = m->data;
 598         par.family    = NFPROTO_BRIDGE;
 599         if (par.match->destroy != NULL)
 600                 par.match->destroy(&par);
 601         module_put(par.match->me);
 602         return 0;
 603 }
 604
 605 static inline int
 606 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 607 {
 608         struct xt_tgdtor_param par;
 609
 610         if (i && (*i)-- == 0)
 611                 return 1;
 612
 613         par.net      = net;
 614         par.target   = w->u.watcher;
 615         par.targinfo = w->data;
 616         par.family   = NFPROTO_BRIDGE;
 617         if (par.target->destroy != NULL)
 618                 par.target->destroy(&par);
 619         module_put(par.target->me);
 620         return 0;
 621 }
 622
 623 static inline int
 624 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 625 {
 626         struct xt_tgdtor_param par;
 627         struct ebt_entry_target *t;
 628
 629         if (e->bitmask == 0)
 630                 return 0;
 631         /* we're done */
 632         if (cnt && (*cnt)-- == 0)
 633                 return 1;
 634         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 635         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 636         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 637
 638         par.net      = net;
 639         par.target   = t->u.target;
 640         par.targinfo = t->data;
 641         par.family   = NFPROTO_BRIDGE;
 642         if (par.target->destroy != NULL)
 643                 par.target->destroy(&par);
 644         module_put(par.target->me);
 645         return 0;
 646 }
 647
 648 static inline int
 649 ebt_check_entry(struct ebt_entry *e, struct net *net,
 650                 const struct ebt_table_info *newinfo,
 651                 const char *name, unsigned int *cnt,
 652                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 653 {
 654         struct ebt_entry_target *t;
 655         struct xt_target *target;
 656         unsigned int i, j, hook = 0, hookmask = 0;
 657         size_t gap;
 658         int ret;
 659         struct xt_mtchk_param mtpar;
 660         struct xt_tgchk_param tgpar;
 661
 662         /* don't mess with the struct ebt_entries */
 663         if (e->bitmask == 0)
 664                 return 0;
 665
 666         if (e->bitmask & ~EBT_F_MASK) {
 667                 BUGPRINT("Unknown flag for bitmask\n");
 668                 return -EINVAL;
 669         }
 670         if (e->invflags & ~EBT_INV_MASK) {
 671                 BUGPRINT("Unknown flag for inv bitmask\n");
 672                 return -EINVAL;
 673         }
 674         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 675                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 676                 return -EINVAL;
 677         }
 678         /* what hook do we belong to? */
 679         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 680                 if (!newinfo->hook_entry[i])
 681                         continue;
 682                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 683                         hook = i;
 684                 else
 685                         break;
 686         }
 687         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 688          * a base chain
 689          */
 690         if (i < NF_BR_NUMHOOKS)
 691                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 692         else {
 693                 for (i = 0; i < udc_cnt; i++)
 694                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 695                                 break;
 696                 if (i == 0)
 697                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 698                 else
 699                         hookmask = cl_s[i - 1].hookmask;
 700         }
 701         i = 0;
 702
 703         mtpar.net       = tgpar.net       = net;
 704         mtpar.table     = tgpar.table     = name;
 705         mtpar.entryinfo = tgpar.entryinfo = e;
 706         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 707         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 708         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 709         if (ret != 0)
 710                 goto cleanup_matches;
 711         j = 0;
 712         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 713         if (ret != 0)
 714                 goto cleanup_watchers;
 715         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 716         gap = e->next_offset - e->target_offset;
 717
 718         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 719         if (IS_ERR(target)) {
 720                 ret = PTR_ERR(target);
 721                 goto cleanup_watchers;
 722         }
 723
 724         t->u.target = target;
 725         if (t->u.target == &ebt_standard_target) {
 726                 if (gap < sizeof(struct ebt_standard_target)) {
 727                         BUGPRINT("Standard target size too big\n");
 728                         ret = -EFAULT;
 729                         goto cleanup_watchers;
 730                 }
 731                 if (((struct ebt_standard_target *)t)->verdict <
 732                    -NUM_STANDARD_TARGETS) {
 733                         BUGPRINT("Invalid standard target\n");
 734                         ret = -EFAULT;
 735                         goto cleanup_watchers;
 736                 }
 737         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 738                 module_put(t->u.target->me);
 739                 ret = -EFAULT;
 740                 goto cleanup_watchers;
 741         }
 742
 743         tgpar.target   = target;
 744         tgpar.targinfo = t->data;
 745         ret = xt_check_target(&tgpar, t->target_size,
 746               e->ethproto, e->invflags & EBT_IPROTO);
 747         if (ret < 0) {
 748                 module_put(target->me);
 749                 goto cleanup_watchers;
 750         }
 751         (*cnt)++;
 752         return 0;
 753 cleanup_watchers:
 754         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 755 cleanup_matches:
 756         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 757         return ret;
 758 }
 759
 760 /* checks for loops and sets the hook mask for udc
 761  * the hook mask for udc tells us from which base chains the udc can be
 762  * accessed. This mask is a parameter to the check() functions of the extensions
 763  */
 764 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 765                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 766 {
 767         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 768         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 769         const struct ebt_entry_target *t;
 770
 771         while (pos < nentries || chain_nr != -1) {
 772                 /* end of udc, go back one 'recursion' step */
 773                 if (pos == nentries) {
 774                         /* put back values of the time when this chain was called */
 775                         e = cl_s[chain_nr].cs.e;
 776                         if (cl_s[chain_nr].from != -1)
 777                                 nentries =
 778                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 779                         else
 780                                 nentries = chain->nentries;
 781                         pos = cl_s[chain_nr].cs.n;
 782                         /* make sure we won't see a loop that isn't one */
 783                         cl_s[chain_nr].cs.n = 0;
 784                         chain_nr = cl_s[chain_nr].from;
 785                         if (pos == nentries)
 786                                 continue;
 787                 }
 788                 t = (struct ebt_entry_target *)
 789                    (((char *)e) + e->target_offset);
 790                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 791                         goto letscontinue;
 792                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 793                    e->next_offset) {
 794                         BUGPRINT("Standard target size too big\n");
 795                         return -1;
 796                 }
 797                 verdict = ((struct ebt_standard_target *)t)->verdict;
 798                 if (verdict >= 0) { /* jump to another chain */
 799                         struct ebt_entries *hlp2 =
 800                            (struct ebt_entries *)(base + verdict);
 801                         for (i = 0; i < udc_cnt; i++)
 802                                 if (hlp2 == cl_s[i].cs.chaininfo)
 803                                         break;
 804                         /* bad destination or loop */
 805                         if (i == udc_cnt) {
 806                                 BUGPRINT("bad destination\n");
 807                                 return -1;
 808                         }
 809                         if (cl_s[i].cs.n) {
 810                                 BUGPRINT("loop\n");
 811                                 return -1;
 812                         }
 813                         if (cl_s[i].hookmask & (1 << hooknr))
 814                                 goto letscontinue;
 815                         /* this can't be 0, so the loop test is correct */
 816                         cl_s[i].cs.n = pos + 1;
 817                         pos = 0;
 818                         cl_s[i].cs.e = ebt_next_entry(e);
 819                         e = (struct ebt_entry *)(hlp2->data);
 820                         nentries = hlp2->nentries;
 821                         cl_s[i].from = chain_nr;
 822                         chain_nr = i;
 823                         /* this udc is accessible from the base chain for hooknr */
 824                         cl_s[i].hookmask |= (1 << hooknr);
 825                         continue;
 826                 }
 827 letscontinue:
 828                 e = ebt_next_entry(e);
 829                 pos++;
 830         }
 831         return 0;
 832 }
 833
 834 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 835 static int translate_table(struct net *net, const char *name,
 836                            struct ebt_table_info *newinfo)
 837 {
 838         unsigned int i, j, k, udc_cnt;
 839         int ret;
 840         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 841
 842         i = 0;
 843         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 844                 i++;
 845         if (i == NF_BR_NUMHOOKS) {
 846                 BUGPRINT("No valid hooks specified\n");
 847                 return -EINVAL;
 848         }
 849         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 850                 BUGPRINT("Chains don't start at beginning\n");
 851                 return -EINVAL;
 852         }
 853         /* make sure chains are ordered after each other in same order
 854          * as their corresponding hooks
 855          */
 856         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 857                 if (!newinfo->hook_entry[j])
 858                         continue;
 859                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 860                         BUGPRINT("Hook order must be followed\n");
 861                         return -EINVAL;
 862                 }
 863                 i = j;
 864         }
 865
 866         /* do some early checkings and initialize some things */
 867         i = 0; /* holds the expected nr. of entries for the chain */
 868         j = 0; /* holds the up to now counted entries for the chain */
 869         k = 0; /* holds the total nr. of entries, should equal
 870                 * newinfo->nentries afterwards
 871                 */
 872         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 873         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 874            ebt_check_entry_size_and_hooks, newinfo,
 875            &i, &j, &k, &udc_cnt);
 876
 877         if (ret != 0)
 878                 return ret;
 879
 880         if (i != j) {
 881                 BUGPRINT("nentries does not equal the nr of entries in the "
 882                          "(last) chain\n");
 883                 return -EINVAL;
 884         }
 885         if (k != newinfo->nentries) {
 886                 BUGPRINT("Total nentries is wrong\n");
 887                 return -EINVAL;
 888         }
 889
 890         /* get the location of the udc, put them in an array
 891          * while we're at it, allocate the chainstack
 892          */
 893         if (udc_cnt) {
 894                 /* this will get free'd in do_replace()/ebt_register_table()
 895                  * if an error occurs
 896                  */
 897                 newinfo->chainstack =
 898                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 899                 if (!newinfo->chainstack)
 900                         return -ENOMEM;
 901                 for_each_possible_cpu(i) {
 902                         newinfo->chainstack[i] =
 903                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 904                         if (!newinfo->chainstack[i]) {
 905                                 while (i)
 906                                         vfree(newinfo->chainstack[--i]);
 907                                 vfree(newinfo->chainstack);
 908                                 newinfo->chainstack = NULL;
 909                                 return -ENOMEM;
 910                         }
 911                 }
 912
 913                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 914                 if (!cl_s)
 915                         return -ENOMEM;
 916                 i = 0; /* the i'th udc */
 917                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 918                    ebt_get_udc_positions, newinfo, &i, cl_s);
 919                 /* sanity check */
 920                 if (i != udc_cnt) {
 921                         BUGPRINT("i != udc_cnt\n");
 922                         vfree(cl_s);
 923                         return -EFAULT;
 924                 }
 925         }
 926
 927         /* Check for loops */
 928         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 929                 if (newinfo->hook_entry[i])
 930                         if (check_chainloops(newinfo->hook_entry[i],
 931                            cl_s, udc_cnt, i, newinfo->entries)) {
 932                                 vfree(cl_s);
 933                                 return -EINVAL;
 934                         }
 935
 936         /* we now know the following (along with E=mc²):
 937          *  - the nr of entries in each chain is right
 938          *  - the size of the allocated space is right
 939          *  - all valid hooks have a corresponding chain
 940          *  - there are no loops
 941          *  - wrong data can still be on the level of a single entry
 942          *  - could be there are jumps to places that are not the
 943          *    beginning of a chain. This can only occur in chains that
 944          *    are not accessible from any base chains, so we don't care.
 945          */
 946
 947         /* used to know what we need to clean up if something goes wrong */
 948         i = 0;
 949         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 950            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 951         if (ret != 0) {
 952                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 953                                   ebt_cleanup_entry, net, &i);
 954         }
 955         vfree(cl_s);
 956         return ret;
 957 }
 958
 959 /* called under write_lock */
 960 static void get_counters(const struct ebt_counter *oldcounters,
 961                          struct ebt_counter *counters, unsigned int nentries)
 962 {
 963         int i, cpu;
 964         struct ebt_counter *counter_base;
 965
 966         /* counters of cpu 0 */
 967         memcpy(counters, oldcounters,
 968                sizeof(struct ebt_counter) * nentries);
 969
 970         /* add other counters to those of cpu 0 */
 971         for_each_possible_cpu(cpu) {
 972                 if (cpu == 0)
 973                         continue;
 974                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 975                 for (i = 0; i < nentries; i++) {
 976                         counters[i].pcnt += counter_base[i].pcnt;
 977                         counters[i].bcnt += counter_base[i].bcnt;
 978                 }
 979         }
 980 }
 981
 982 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 983                               struct ebt_table_info *newinfo)
 984 {
 985         int ret, i;
 986         struct ebt_counter *counterstmp = NULL;
 987         /* used to be able to unlock earlier */
 988         struct ebt_table_info *table;
 989         struct ebt_table *t;
 990
 991         /* the user wants counters back
 992          * the check on the size is done later, when we have the lock
 993          */
 994         if (repl->num_counters) {
 995                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 996                 counterstmp = vmalloc(size);
 997                 if (!counterstmp)
 998                         return -ENOMEM;
 999         }
1000
1001         newinfo->chainstack = NULL;
1002         ret = ebt_verify_pointers(repl, newinfo);
1003         if (ret != 0)
1004                 goto free_counterstmp;
1005
1006         ret = translate_table(net, repl->name, newinfo);
1007
1008         if (ret != 0)
1009                 goto free_counterstmp;
1010
1011         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1012         if (!t) {
1013                 ret = -ENOENT;
1014                 goto free_iterate;
1015         }
1016
1017         /* the table doesn't like it */
1018         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1019                 goto free_unlock;
1020
1021         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1022                 BUGPRINT("Wrong nr. of counters requested\n");
1023                 ret = -EINVAL;
1024                 goto free_unlock;
1025         }
1026
1027         /* we have the mutex lock, so no danger in reading this pointer */
1028         table = t->private;
1029         /* make sure the table can only be rmmod'ed if it contains no rules */
1030         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1031                 ret = -ENOENT;
1032                 goto free_unlock;
1033         } else if (table->nentries && !newinfo->nentries)
1034                 module_put(t->me);
1035         /* we need an atomic snapshot of the counters */
1036         write_lock_bh(&t->lock);
1037         if (repl->num_counters)
1038                 get_counters(t->private->counters, counterstmp,
1039                    t->private->nentries);
1040
1041         t->private = newinfo;
1042         write_unlock_bh(&t->lock);
1043         mutex_unlock(&ebt_mutex);
1044         /* so, a user can change the chains while having messed up her counter
1045          * allocation. Only reason why this is done is because this way the lock
1046          * is held only once, while this doesn't bring the kernel into a
1047          * dangerous state.
1048          */
1049         if (repl->num_counters &&
1050            copy_to_user(repl->counters, counterstmp,
1051            repl->num_counters * sizeof(struct ebt_counter))) {
1052                 /* Silent error, can't fail, new table is already in place */
1053                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1054         }
1055
1056         /* decrease module count and free resources */
1057         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1058                           ebt_cleanup_entry, net, NULL);
1059
1060         vfree(table->entries);
1061         if (table->chainstack) {
1062                 for_each_possible_cpu(i)
1063                         vfree(table->chainstack[i]);
1064                 vfree(table->chainstack);
1065         }
1066         vfree(table);
1067
1068         vfree(counterstmp);
1069
1070 #ifdef CONFIG_AUDIT
1071         if (audit_enabled) {
1072                 struct audit_buffer *ab;
1073
1074                 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1075                                      AUDIT_NETFILTER_CFG);
1076                 if (ab) {
1077                         audit_log_format(ab, "table=%s family=%u entries=%u",
1078                                          repl->name, AF_BRIDGE, repl->nentries);
1079                         audit_log_end(ab);
1080                 }
1081         }
1082 #endif
1083         return ret;
1084
1085 free_unlock:
1086         mutex_unlock(&ebt_mutex);
1087 free_iterate:
1088         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1089                           ebt_cleanup_entry, net, NULL);
1090 free_counterstmp:
1091         vfree(counterstmp);
1092         /* can be initialized in translate_table() */
1093         if (newinfo->chainstack) {
1094                 for_each_possible_cpu(i)
1095                         vfree(newinfo->chainstack[i]);
1096                 vfree(newinfo->chainstack);
1097         }
1098         return ret;
1099 }
1100
1101 /* replace the table */
1102 static int do_replace(struct net *net, const void __user *user,
1103                       unsigned int len)
1104 {
1105         int ret, countersize;
1106         struct ebt_table_info *newinfo;
1107         struct ebt_replace tmp;
1108
1109         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1110                 return -EFAULT;
1111
1112         if (len != sizeof(tmp) + tmp.entries_size) {
1113                 BUGPRINT("Wrong len argument\n");
1114                 return -EINVAL;
1115         }
1116
1117         if (tmp.entries_size == 0) {
1118                 BUGPRINT("Entries_size never zero\n");
1119                 return -EINVAL;
1120         }
1121         /* overflow check */
1122         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1123                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1124                 return -ENOMEM;
1125         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1126                 return -ENOMEM;
1127
1128         tmp.name[sizeof(tmp.name) - 1] = 0;
1129
1130         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1131         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1132         if (!newinfo)
1133                 return -ENOMEM;
1134
1135         if (countersize)
1136                 memset(newinfo->counters, 0, countersize);
1137
1138         newinfo->entries = vmalloc(tmp.entries_size);
1139         if (!newinfo->entries) {
1140                 ret = -ENOMEM;
1141                 goto free_newinfo;
1142         }
1143         if (copy_from_user(
1144            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1145                 BUGPRINT("Couldn't copy entries from userspace\n");
1146                 ret = -EFAULT;
1147                 goto free_entries;
1148         }
1149
1150         ret = do_replace_finish(net, &tmp, newinfo);
1151         if (ret == 0)
1152                 return ret;
1153 free_entries:
1154         vfree(newinfo->entries);
1155 free_newinfo:
1156         vfree(newinfo);
1157         return ret;
1158 }
1159
1160 struct ebt_table *
1161 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1162 {
1163         struct ebt_table_info *newinfo;
1164         struct ebt_table *t, *table;
1165         struct ebt_replace_kernel *repl;
1166         int ret, i, countersize;
1167         void *p;
1168
1169         if (input_table == NULL || (repl = input_table->table) == NULL ||
1170             repl->entries == NULL || repl->entries_size == 0 ||
1171             repl->counters != NULL || input_table->private != NULL) {
1172                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1173                 return ERR_PTR(-EINVAL);
1174         }
1175
1176         /* Don't add one table to multiple lists. */
1177         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1178         if (!table) {
1179                 ret = -ENOMEM;
1180                 goto out;
1181         }
1182
1183         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1184         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1185         ret = -ENOMEM;
1186         if (!newinfo)
1187                 goto free_table;
1188
1189         p = vmalloc(repl->entries_size);
1190         if (!p)
1191                 goto free_newinfo;
1192
1193         memcpy(p, repl->entries, repl->entries_size);
1194         newinfo->entries = p;
1195
1196         newinfo->entries_size = repl->entries_size;
1197         newinfo->nentries = repl->nentries;
1198
1199         if (countersize)
1200                 memset(newinfo->counters, 0, countersize);
1201
1202         /* fill in newinfo and parse the entries */
1203         newinfo->chainstack = NULL;
1204         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1205                 if ((repl->valid_hooks & (1 << i)) == 0)
1206                         newinfo->hook_entry[i] = NULL;
1207                 else
1208                         newinfo->hook_entry[i] = p +
1209                                 ((char *)repl->hook_entry[i] - repl->entries);
1210         }
1211         ret = translate_table(net, repl->name, newinfo);
1212         if (ret != 0) {
1213                 BUGPRINT("Translate_table failed\n");
1214                 goto free_chainstack;
1215         }
1216
1217         if (table->check && table->check(newinfo, table->valid_hooks)) {
1218                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1219                 ret = -EINVAL;
1220                 goto free_chainstack;
1221         }
1222
1223         table->private = newinfo;
1224         rwlock_init(&table->lock);
1225         mutex_lock(&ebt_mutex);
1226         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1227                 if (strcmp(t->name, table->name) == 0) {
1228                         ret = -EEXIST;
1229                         BUGPRINT("Table name already exists\n");
1230                         goto free_unlock;
1231                 }
1232         }
1233
1234         /* Hold a reference count if the chains aren't empty */
1235         if (newinfo->nentries && !try_module_get(table->me)) {
1236                 ret = -ENOENT;
1237                 goto free_unlock;
1238         }
1239         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1240         mutex_unlock(&ebt_mutex);
1241         return table;
1242 free_unlock:
1243         mutex_unlock(&ebt_mutex);
1244 free_chainstack:
1245         if (newinfo->chainstack) {
1246                 for_each_possible_cpu(i)
1247                         vfree(newinfo->chainstack[i]);
1248                 vfree(newinfo->chainstack);
1249         }
1250         vfree(newinfo->entries);
1251 free_newinfo:
1252         vfree(newinfo);
1253 free_table:
1254         kfree(table);
1255 out:
1256         return ERR_PTR(ret);
1257 }
1258
1259 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1260 {
1261         int i;
1262
1263         if (!table) {
1264                 BUGPRINT("Request to unregister NULL table!!!\n");
1265                 return;
1266         }
1267         mutex_lock(&ebt_mutex);
1268         list_del(&table->list);
1269         mutex_unlock(&ebt_mutex);
1270         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1271                           ebt_cleanup_entry, net, NULL);
1272         if (table->private->nentries)
1273                 module_put(table->me);
1274         vfree(table->private->entries);
1275         if (table->private->chainstack) {
1276                 for_each_possible_cpu(i)
1277                         vfree(table->private->chainstack[i]);
1278                 vfree(table->private->chainstack);
1279         }
1280         vfree(table->private);
1281         kfree(table);
1282 }
1283
1284 /* userspace just supplied us with counters */
1285 static int do_update_counters(struct net *net, const char *name,
1286                                 struct ebt_counter __user *counters,
1287                                 unsigned int num_counters,
1288                                 const void __user *user, unsigned int len)
1289 {
1290         int i, ret;
1291         struct ebt_counter *tmp;
1292         struct ebt_table *t;
1293
1294         if (num_counters == 0)
1295                 return -EINVAL;
1296
1297         tmp = vmalloc(num_counters * sizeof(*tmp));
1298         if (!tmp)
1299                 return -ENOMEM;
1300
1301         t = find_table_lock(net, name, &ret, &ebt_mutex);
1302         if (!t)
1303                 goto free_tmp;
1304
1305         if (num_counters != t->private->nentries) {
1306                 BUGPRINT("Wrong nr of counters\n");
1307                 ret = -EINVAL;
1308                 goto unlock_mutex;
1309         }
1310
1311         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1312                 ret = -EFAULT;
1313                 goto unlock_mutex;
1314         }
1315
1316         /* we want an atomic add of the counters */
1317         write_lock_bh(&t->lock);
1318
1319         /* we add to the counters of the first cpu */
1320         for (i = 0; i < num_counters; i++) {
1321                 t->private->counters[i].pcnt += tmp[i].pcnt;
1322                 t->private->counters[i].bcnt += tmp[i].bcnt;
1323         }
1324
1325         write_unlock_bh(&t->lock);
1326         ret = 0;
1327 unlock_mutex:
1328         mutex_unlock(&ebt_mutex);
1329 free_tmp:
1330         vfree(tmp);
1331         return ret;
1332 }
1333
1334 static int update_counters(struct net *net, const void __user *user,
1335                             unsigned int len)
1336 {
1337         struct ebt_replace hlp;
1338
1339         if (copy_from_user(&hlp, user, sizeof(hlp)))
1340                 return -EFAULT;
1341
1342         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1343                 return -EINVAL;
1344
1345         return do_update_counters(net, hlp.name, hlp.counters,
1346                                 hlp.num_counters, user, len);
1347 }
1348
1349 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1350                                      const char *base, char __user *ubase)
1351 {
1352         char __user *hlp = ubase + ((char *)m - base);
1353         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1354
1355         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1356          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1357          */
1358         strlcpy(name, m->u.match->name, sizeof(name));
1359         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1360                 return -EFAULT;
1361         return 0;
1362 }
1363
1364 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1365                                        const char *base, char __user *ubase)
1366 {
1367         char __user *hlp = ubase + ((char *)w - base);
1368         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1369
1370         strlcpy(name, w->u.watcher->name, sizeof(name));
1371         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1372                 return -EFAULT;
1373         return 0;
1374 }
1375
1376 static inline int ebt_make_names(struct ebt_entry *e, const char *base,
1377                                  char __user *ubase)
1378 {
1379         int ret;
1380         char __user *hlp;
1381         const struct ebt_entry_target *t;
1382         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1383
1384         if (e->bitmask == 0)
1385                 return 0;
1386
1387         hlp = ubase + (((char *)e + e->target_offset) - base);
1388         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1389
1390         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1391         if (ret != 0)
1392                 return ret;
1393         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1394         if (ret != 0)
1395                 return ret;
1396         strlcpy(name, t->u.target->name, sizeof(name));
1397         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1398                 return -EFAULT;
1399         return 0;
1400 }
1401
1402 static int copy_counters_to_user(struct ebt_table *t,
1403                                  const struct ebt_counter *oldcounters,
1404                                  void __user *user, unsigned int num_counters,
1405                                  unsigned int nentries)
1406 {
1407         struct ebt_counter *counterstmp;
1408         int ret = 0;
1409
1410         /* userspace might not need the counters */
1411         if (num_counters == 0)
1412                 return 0;
1413
1414         if (num_counters != nentries) {
1415                 BUGPRINT("Num_counters wrong\n");
1416                 return -EINVAL;
1417         }
1418
1419         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1420         if (!counterstmp)
1421                 return -ENOMEM;
1422
1423         write_lock_bh(&t->lock);
1424         get_counters(oldcounters, counterstmp, nentries);
1425         write_unlock_bh(&t->lock);
1426
1427         if (copy_to_user(user, counterstmp,
1428            nentries * sizeof(struct ebt_counter)))
1429                 ret = -EFAULT;
1430         vfree(counterstmp);
1431         return ret;
1432 }
1433
1434 /* called with ebt_mutex locked */
1435 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1436                                    const int *len, int cmd)
1437 {
1438         struct ebt_replace tmp;
1439         const struct ebt_counter *oldcounters;
1440         unsigned int entries_size, nentries;
1441         int ret;
1442         char *entries;
1443
1444         if (cmd == EBT_SO_GET_ENTRIES) {
1445                 entries_size = t->private->entries_size;
1446                 nentries = t->private->nentries;
1447                 entries = t->private->entries;
1448                 oldcounters = t->private->counters;
1449         } else {
1450                 entries_size = t->table->entries_size;
1451                 nentries = t->table->nentries;
1452                 entries = t->table->entries;
1453                 oldcounters = t->table->counters;
1454         }
1455
1456         if (copy_from_user(&tmp, user, sizeof(tmp)))
1457                 return -EFAULT;
1458
1459         if (*len != sizeof(struct ebt_replace) + entries_size +
1460            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1461                 return -EINVAL;
1462
1463         if (tmp.nentries != nentries) {
1464                 BUGPRINT("Nentries wrong\n");
1465                 return -EINVAL;
1466         }
1467
1468         if (tmp.entries_size != entries_size) {
1469                 BUGPRINT("Wrong size\n");
1470                 return -EINVAL;
1471         }
1472
1473         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1474                                         tmp.num_counters, nentries);
1475         if (ret)
1476                 return ret;
1477
1478         if (copy_to_user(tmp.entries, entries, entries_size)) {
1479                 BUGPRINT("Couldn't copy entries to userspace\n");
1480                 return -EFAULT;
1481         }
1482         /* set the match/watcher/target names right */
1483         return EBT_ENTRY_ITERATE(entries, entries_size,
1484            ebt_make_names, entries, tmp.entries);
1485 }
1486
1487 static int do_ebt_set_ctl(struct sock *sk,
1488         int cmd, void __user *user, unsigned int len)
1489 {
1490         int ret;
1491         struct net *net = sock_net(sk);
1492
1493         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1494                 return -EPERM;
1495
1496         switch (cmd) {
1497         case EBT_SO_SET_ENTRIES:
1498                 ret = do_replace(net, user, len);
1499                 break;
1500         case EBT_SO_SET_COUNTERS:
1501                 ret = update_counters(net, user, len);
1502                 break;
1503         default:
1504                 ret = -EINVAL;
1505         }
1506         return ret;
1507 }
1508
1509 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1510 {
1511         int ret;
1512         struct ebt_replace tmp;
1513         struct ebt_table *t;
1514         struct net *net = sock_net(sk);
1515
1516         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1517                 return -EPERM;
1518
1519         if (copy_from_user(&tmp, user, sizeof(tmp)))
1520                 return -EFAULT;
1521
1522         tmp.name[sizeof(tmp.name) - 1] = '\0';
1523
1524         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1525         if (!t)
1526                 return ret;
1527
1528         switch (cmd) {
1529         case EBT_SO_GET_INFO:
1530         case EBT_SO_GET_INIT_INFO:
1531                 if (*len != sizeof(struct ebt_replace)) {
1532                         ret = -EINVAL;
1533                         mutex_unlock(&ebt_mutex);
1534                         break;
1535                 }
1536                 if (cmd == EBT_SO_GET_INFO) {
1537                         tmp.nentries = t->private->nentries;
1538                         tmp.entries_size = t->private->entries_size;
1539                         tmp.valid_hooks = t->valid_hooks;
1540                 } else {
1541                         tmp.nentries = t->table->nentries;
1542                         tmp.entries_size = t->table->entries_size;
1543                         tmp.valid_hooks = t->table->valid_hooks;
1544                 }
1545                 mutex_unlock(&ebt_mutex);
1546                 if (copy_to_user(user, &tmp, *len) != 0) {
1547                         BUGPRINT("c2u Didn't work\n");
1548                         ret = -EFAULT;
1549                         break;
1550                 }
1551                 ret = 0;
1552                 break;
1553
1554         case EBT_SO_GET_ENTRIES:
1555         case EBT_SO_GET_INIT_ENTRIES:
1556                 ret = copy_everything_to_user(t, user, len, cmd);
1557                 mutex_unlock(&ebt_mutex);
1558                 break;
1559
1560         default:
1561                 mutex_unlock(&ebt_mutex);
1562                 ret = -EINVAL;
1563         }
1564
1565         return ret;
1566 }
1567
1568 #ifdef CONFIG_COMPAT
1569 /* 32 bit-userspace compatibility definitions. */
1570 struct compat_ebt_replace {
1571         char name[EBT_TABLE_MAXNAMELEN];
1572         compat_uint_t valid_hooks;
1573         compat_uint_t nentries;
1574         compat_uint_t entries_size;
1575         /* start of the chains */
1576         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1577         /* nr of counters userspace expects back */
1578         compat_uint_t num_counters;
1579         /* where the kernel will put the old counters. */
1580         compat_uptr_t counters;
1581         compat_uptr_t entries;
1582 };
1583
1584 /* struct ebt_entry_match, _target and _watcher have same layout */
1585 struct compat_ebt_entry_mwt {
1586         union {
1587                 char name[EBT_FUNCTION_MAXNAMELEN];
1588                 compat_uptr_t ptr;
1589         } u;
1590         compat_uint_t match_size;
1591         compat_uint_t data[0];
1592 };
1593
1594 /* account for possible padding between match_size and ->data */
1595 static int ebt_compat_entry_padsize(void)
1596 {
1597         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1598                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1599         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1600                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1601 }
1602
1603 static int ebt_compat_match_offset(const struct xt_match *match,
1604                                    unsigned int userlen)
1605 {
1606         /* ebt_among needs special handling. The kernel .matchsize is
1607          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1608          * value is expected.
1609          * Example: userspace sends 4500, ebt_among.c wants 4504.
1610          */
1611         if (unlikely(match->matchsize == -1))
1612                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1613         return xt_compat_match_offset(match);
1614 }
1615
1616 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1617                                 unsigned int *size)
1618 {
1619         const struct xt_match *match = m->u.match;
1620         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1621         int off = ebt_compat_match_offset(match, m->match_size);
1622         compat_uint_t msize = m->match_size - off;
1623
1624         BUG_ON(off >= m->match_size);
1625
1626         if (copy_to_user(cm->u.name, match->name,
1627             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1628                 return -EFAULT;
1629
1630         if (match->compat_to_user) {
1631                 if (match->compat_to_user(cm->data, m->data))
1632                         return -EFAULT;
1633         } else if (copy_to_user(cm->data, m->data, msize))
1634                         return -EFAULT;
1635
1636         *size -= ebt_compat_entry_padsize() + off;
1637         *dstptr = cm->data;
1638         *dstptr += msize;
1639         return 0;
1640 }
1641
1642 static int compat_target_to_user(struct ebt_entry_target *t,
1643                                  void __user **dstptr,
1644                                  unsigned int *size)
1645 {
1646         const struct xt_target *target = t->u.target;
1647         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1648         int off = xt_compat_target_offset(target);
1649         compat_uint_t tsize = t->target_size - off;
1650
1651         BUG_ON(off >= t->target_size);
1652
1653         if (copy_to_user(cm->u.name, target->name,
1654             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1655                 return -EFAULT;
1656
1657         if (target->compat_to_user) {
1658                 if (target->compat_to_user(cm->data, t->data))
1659                         return -EFAULT;
1660         } else if (copy_to_user(cm->data, t->data, tsize))
1661                 return -EFAULT;
1662
1663         *size -= ebt_compat_entry_padsize() + off;
1664         *dstptr = cm->data;
1665         *dstptr += tsize;
1666         return 0;
1667 }
1668
1669 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1670                                   void __user **dstptr,
1671                                   unsigned int *size)
1672 {
1673         return compat_target_to_user((struct ebt_entry_target *)w,
1674                                                         dstptr, size);
1675 }
1676
1677 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1678                                 unsigned int *size)
1679 {
1680         struct ebt_entry_target *t;
1681         struct ebt_entry __user *ce;
1682         u32 watchers_offset, target_offset, next_offset;
1683         compat_uint_t origsize;
1684         int ret;
1685
1686         if (e->bitmask == 0) {
1687                 if (*size < sizeof(struct ebt_entries))
1688                         return -EINVAL;
1689                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1690                         return -EFAULT;
1691
1692                 *dstptr += sizeof(struct ebt_entries);
1693                 *size -= sizeof(struct ebt_entries);
1694                 return 0;
1695         }
1696
1697         if (*size < sizeof(*ce))
1698                 return -EINVAL;
1699
1700         ce = (struct ebt_entry __user *)*dstptr;
1701         if (copy_to_user(ce, e, sizeof(*ce)))
1702                 return -EFAULT;
1703
1704         origsize = *size;
1705         *dstptr += sizeof(*ce);
1706
1707         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1708         if (ret)
1709                 return ret;
1710         watchers_offset = e->watchers_offset - (origsize - *size);
1711
1712         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1713         if (ret)
1714                 return ret;
1715         target_offset = e->target_offset - (origsize - *size);
1716
1717         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1718
1719         ret = compat_target_to_user(t, dstptr, size);
1720         if (ret)
1721                 return ret;
1722         next_offset = e->next_offset - (origsize - *size);
1723
1724         if (put_user(watchers_offset, &ce->watchers_offset) ||
1725             put_user(target_offset, &ce->target_offset) ||
1726             put_user(next_offset, &ce->next_offset))
1727                 return -EFAULT;
1728
1729         *size -= sizeof(*ce);
1730         return 0;
1731 }
1732
1733 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1734 {
1735         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1736         *off += ebt_compat_entry_padsize();
1737         return 0;
1738 }
1739
1740 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1741 {
1742         *off += xt_compat_target_offset(w->u.watcher);
1743         *off += ebt_compat_entry_padsize();
1744         return 0;
1745 }
1746
1747 static int compat_calc_entry(const struct ebt_entry *e,
1748                              const struct ebt_table_info *info,
1749                              const void *base,
1750                              struct compat_ebt_replace *newinfo)
1751 {
1752         const struct ebt_entry_target *t;
1753         unsigned int entry_offset;
1754         int off, ret, i;
1755
1756         if (e->bitmask == 0)
1757                 return 0;
1758
1759         off = 0;
1760         entry_offset = (void *)e - base;
1761
1762         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1763         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1764
1765         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1766
1767         off += xt_compat_target_offset(t->u.target);
1768         off += ebt_compat_entry_padsize();
1769
1770         newinfo->entries_size -= off;
1771
1772         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1773         if (ret)
1774                 return ret;
1775
1776         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1777                 const void *hookptr = info->hook_entry[i];
1778                 if (info->hook_entry[i] &&
1779                     (e < (struct ebt_entry *)(base - hookptr))) {
1780                         newinfo->hook_entry[i] -= off;
1781                         pr_debug("0x%08X -> 0x%08X\n",
1782                                         newinfo->hook_entry[i] + off,
1783                                         newinfo->hook_entry[i]);
1784                 }
1785         }
1786
1787         return 0;
1788 }
1789
1790
1791 static int compat_table_info(const struct ebt_table_info *info,
1792                              struct compat_ebt_replace *newinfo)
1793 {
1794         unsigned int size = info->entries_size;
1795         const void *entries = info->entries;
1796
1797         newinfo->entries_size = size;
1798
1799         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1800         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1801                                                         entries, newinfo);
1802 }
1803
1804 static int compat_copy_everything_to_user(struct ebt_table *t,
1805                                           void __user *user, int *len, int cmd)
1806 {
1807         struct compat_ebt_replace repl, tmp;
1808         struct ebt_counter *oldcounters;
1809         struct ebt_table_info tinfo;
1810         int ret;
1811         void __user *pos;
1812
1813         memset(&tinfo, 0, sizeof(tinfo));
1814
1815         if (cmd == EBT_SO_GET_ENTRIES) {
1816                 tinfo.entries_size = t->private->entries_size;
1817                 tinfo.nentries = t->private->nentries;
1818                 tinfo.entries = t->private->entries;
1819                 oldcounters = t->private->counters;
1820         } else {
1821                 tinfo.entries_size = t->table->entries_size;
1822                 tinfo.nentries = t->table->nentries;
1823                 tinfo.entries = t->table->entries;
1824                 oldcounters = t->table->counters;
1825         }
1826
1827         if (copy_from_user(&tmp, user, sizeof(tmp)))
1828                 return -EFAULT;
1829
1830         if (tmp.nentries != tinfo.nentries ||
1831            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1832                 return -EINVAL;
1833
1834         memcpy(&repl, &tmp, sizeof(repl));
1835         if (cmd == EBT_SO_GET_ENTRIES)
1836                 ret = compat_table_info(t->private, &repl);
1837         else
1838                 ret = compat_table_info(&tinfo, &repl);
1839         if (ret)
1840                 return ret;
1841
1842         if (*len != sizeof(tmp) + repl.entries_size +
1843            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1844                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1845                                 *len, tinfo.entries_size, repl.entries_size);
1846                 return -EINVAL;
1847         }
1848
1849         /* userspace might not need the counters */
1850         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1851                                         tmp.num_counters, tinfo.nentries);
1852         if (ret)
1853                 return ret;
1854
1855         pos = compat_ptr(tmp.entries);
1856         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1857                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1858 }
1859
1860 struct ebt_entries_buf_state {
1861         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1862         u32 buf_kern_len;       /* total size of kernel buffer */
1863         u32 buf_kern_offset;    /* amount of data copied so far */
1864         u32 buf_user_offset;    /* read position in userspace buffer */
1865 };
1866
1867 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1868 {
1869         state->buf_kern_offset += sz;
1870         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1871 }
1872
1873 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1874                        void *data, unsigned int sz)
1875 {
1876         if (state->buf_kern_start == NULL)
1877                 goto count_only;
1878
1879         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1880
1881         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1882
1883  count_only:
1884         state->buf_user_offset += sz;
1885         return ebt_buf_count(state, sz);
1886 }
1887
1888 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1889 {
1890         char *b = state->buf_kern_start;
1891
1892         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1893
1894         if (b != NULL && sz > 0)
1895                 memset(b + state->buf_kern_offset, 0, sz);
1896         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1897         return ebt_buf_count(state, sz);
1898 }
1899
1900 enum compat_mwt {
1901         EBT_COMPAT_MATCH,
1902         EBT_COMPAT_WATCHER,
1903         EBT_COMPAT_TARGET,
1904 };
1905
1906 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1907                                 enum compat_mwt compat_mwt,
1908                                 struct ebt_entries_buf_state *state,
1909                                 const unsigned char *base)
1910 {
1911         char name[EBT_FUNCTION_MAXNAMELEN];
1912         struct xt_match *match;
1913         struct xt_target *wt;
1914         void *dst = NULL;
1915         int off, pad = 0;
1916         unsigned int size_kern, match_size = mwt->match_size;
1917
1918         strlcpy(name, mwt->u.name, sizeof(name));
1919
1920         if (state->buf_kern_start)
1921                 dst = state->buf_kern_start + state->buf_kern_offset;
1922
1923         switch (compat_mwt) {
1924         case EBT_COMPAT_MATCH:
1925                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1926                 if (IS_ERR(match))
1927                         return PTR_ERR(match);
1928
1929                 off = ebt_compat_match_offset(match, match_size);
1930                 if (dst) {
1931                         if (match->compat_from_user)
1932                                 match->compat_from_user(dst, mwt->data);
1933                         else
1934                                 memcpy(dst, mwt->data, match_size);
1935                 }
1936
1937                 size_kern = match->matchsize;
1938                 if (unlikely(size_kern == -1))
1939                         size_kern = match_size;
1940                 module_put(match->me);
1941                 break;
1942         case EBT_COMPAT_WATCHER: /* fallthrough */
1943         case EBT_COMPAT_TARGET:
1944                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1945                 if (IS_ERR(wt))
1946                         return PTR_ERR(wt);
1947                 off = xt_compat_target_offset(wt);
1948
1949                 if (dst) {
1950                         if (wt->compat_from_user)
1951                                 wt->compat_from_user(dst, mwt->data);
1952                         else
1953                                 memcpy(dst, mwt->data, match_size);
1954                 }
1955
1956                 size_kern = wt->targetsize;
1957                 module_put(wt->me);
1958                 break;
1959
1960         default:
1961                 return -EINVAL;
1962         }
1963
1964         state->buf_kern_offset += match_size + off;
1965         state->buf_user_offset += match_size;
1966         pad = XT_ALIGN(size_kern) - size_kern;
1967
1968         if (pad > 0 && dst) {
1969                 BUG_ON(state->buf_kern_len <= pad);
1970                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1971                 memset(dst + size_kern, 0, pad);
1972         }
1973         return off + match_size;
1974 }
1975
1976 /* return size of all matches, watchers or target, including necessary
1977  * alignment and padding.
1978  */
1979 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1980                         unsigned int size_left, enum compat_mwt type,
1981                         struct ebt_entries_buf_state *state, const void *base)
1982 {
1983         int growth = 0;
1984         char *buf;
1985
1986         if (size_left == 0)
1987                 return 0;
1988
1989         buf = (char *) match32;
1990
1991         while (size_left >= sizeof(*match32)) {
1992                 struct ebt_entry_match *match_kern;
1993                 int ret;
1994
1995                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1996                 if (match_kern) {
1997                         char *tmp;
1998                         tmp = state->buf_kern_start + state->buf_kern_offset;
1999                         match_kern = (struct ebt_entry_match *) tmp;
2000                 }
2001                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2002                 if (ret < 0)
2003                         return ret;
2004                 size_left -= sizeof(*match32);
2005
2006                 /* add padding before match->data (if any) */
2007                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2008                 if (ret < 0)
2009                         return ret;
2010
2011                 if (match32->match_size > size_left)
2012                         return -EINVAL;
2013
2014                 size_left -= match32->match_size;
2015
2016                 ret = compat_mtw_from_user(match32, type, state, base);
2017                 if (ret < 0)
2018                         return ret;
2019
2020                 BUG_ON(ret < match32->match_size);
2021                 growth += ret - match32->match_size;
2022                 growth += ebt_compat_entry_padsize();
2023
2024                 buf += sizeof(*match32);
2025                 buf += match32->match_size;
2026
2027                 if (match_kern)
2028                         match_kern->match_size = ret;
2029
2030                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2031                 match32 = (struct compat_ebt_entry_mwt *) buf;
2032         }
2033
2034         return growth;
2035 }
2036
2037 /* called for all ebt_entry structures. */
2038 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2039                           unsigned int *total,
2040                           struct ebt_entries_buf_state *state)
2041 {
2042         unsigned int i, j, startoff, new_offset = 0;
2043         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2044         unsigned int offsets[4];
2045         unsigned int *offsets_update = NULL;
2046         int ret;
2047         char *buf_start;
2048
2049         if (*total < sizeof(struct ebt_entries))
2050                 return -EINVAL;
2051
2052         if (!entry->bitmask) {
2053                 *total -= sizeof(struct ebt_entries);
2054                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2055         }
2056         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2057                 return -EINVAL;
2058
2059         startoff = state->buf_user_offset;
2060         /* pull in most part of ebt_entry, it does not need to be changed. */
2061         ret = ebt_buf_add(state, entry,
2062                         offsetof(struct ebt_entry, watchers_offset));
2063         if (ret < 0)
2064                 return ret;
2065
2066         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2067         memcpy(&offsets[1], &entry->watchers_offset,
2068                         sizeof(offsets) - sizeof(offsets[0]));
2069
2070         if (state->buf_kern_start) {
2071                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2072                 offsets_update = (unsigned int *) buf_start;
2073         }
2074         ret = ebt_buf_add(state, &offsets[1],
2075                         sizeof(offsets) - sizeof(offsets[0]));
2076         if (ret < 0)
2077                 return ret;
2078         buf_start = (char *) entry;
2079         /* 0: matches offset, always follows ebt_entry.
2080          * 1: watchers offset, from ebt_entry structure
2081          * 2: target offset, from ebt_entry structure
2082          * 3: next ebt_entry offset, from ebt_entry structure
2083          *
2084          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2085          */
2086         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2087                 struct compat_ebt_entry_mwt *match32;
2088                 unsigned int size;
2089                 char *buf = buf_start;
2090
2091                 buf = buf_start + offsets[i];
2092                 if (offsets[i] > offsets[j])
2093                         return -EINVAL;
2094
2095                 match32 = (struct compat_ebt_entry_mwt *) buf;
2096                 size = offsets[j] - offsets[i];
2097                 ret = ebt_size_mwt(match32, size, i, state, base);
2098                 if (ret < 0)
2099                         return ret;
2100                 new_offset += ret;
2101                 if (offsets_update && new_offset) {
2102                         pr_debug("change offset %d to %d\n",
2103                                 offsets_update[i], offsets[j] + new_offset);
2104                         offsets_update[i] = offsets[j] + new_offset;
2105                 }
2106         }
2107
2108         if (state->buf_kern_start == NULL) {
2109                 unsigned int offset = buf_start - (char *) base;
2110
2111                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2112                 if (ret < 0)
2113                         return ret;
2114         }
2115
2116         startoff = state->buf_user_offset - startoff;
2117
2118         BUG_ON(*total < startoff);
2119         *total -= startoff;
2120         return 0;
2121 }
2122
2123 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2124  * It might need more memory when copied to a 64 bit kernel in case
2125  * userspace is 32-bit. So, first task: find out how much memory is needed.
2126  *
2127  * Called before validation is performed.
2128  */
2129 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2130                                 struct ebt_entries_buf_state *state)
2131 {
2132         unsigned int size_remaining = size_user;
2133         int ret;
2134
2135         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2136                                         &size_remaining, state);
2137         if (ret < 0)
2138                 return ret;
2139
2140         WARN_ON(size_remaining);
2141         return state->buf_kern_offset;
2142 }
2143
2144
2145 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2146                                             void __user *user, unsigned int len)
2147 {
2148         struct compat_ebt_replace tmp;
2149         int i;
2150
2151         if (len < sizeof(tmp))
2152                 return -EINVAL;
2153
2154         if (copy_from_user(&tmp, user, sizeof(tmp)))
2155                 return -EFAULT;
2156
2157         if (len != sizeof(tmp) + tmp.entries_size)
2158                 return -EINVAL;
2159
2160         if (tmp.entries_size == 0)
2161                 return -EINVAL;
2162
2163         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2164                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2165                 return -ENOMEM;
2166         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2167                 return -ENOMEM;
2168
2169         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2170
2171         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2172         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2173                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2174
2175         repl->num_counters = tmp.num_counters;
2176         repl->counters = compat_ptr(tmp.counters);
2177         repl->entries = compat_ptr(tmp.entries);
2178         return 0;
2179 }
2180
2181 static int compat_do_replace(struct net *net, void __user *user,
2182                              unsigned int len)
2183 {
2184         int ret, i, countersize, size64;
2185         struct ebt_table_info *newinfo;
2186         struct ebt_replace tmp;
2187         struct ebt_entries_buf_state state;
2188         void *entries_tmp;
2189
2190         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2191         if (ret) {
2192                 /* try real handler in case userland supplied needed padding */
2193                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2194                         ret = 0;
2195                 return ret;
2196         }
2197
2198         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2199         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2200         if (!newinfo)
2201                 return -ENOMEM;
2202
2203         if (countersize)
2204                 memset(newinfo->counters, 0, countersize);
2205
2206         memset(&state, 0, sizeof(state));
2207
2208         newinfo->entries = vmalloc(tmp.entries_size);
2209         if (!newinfo->entries) {
2210                 ret = -ENOMEM;
2211                 goto free_newinfo;
2212         }
2213         if (copy_from_user(
2214            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2215                 ret = -EFAULT;
2216                 goto free_entries;
2217         }
2218
2219         entries_tmp = newinfo->entries;
2220
2221         xt_compat_lock(NFPROTO_BRIDGE);
2222
2223         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2224         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2225         if (ret < 0)
2226                 goto out_unlock;
2227
2228         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2229                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2230                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2231
2232         size64 = ret;
2233         newinfo->entries = vmalloc(size64);
2234         if (!newinfo->entries) {
2235                 vfree(entries_tmp);
2236                 ret = -ENOMEM;
2237                 goto out_unlock;
2238         }
2239
2240         memset(&state, 0, sizeof(state));
2241         state.buf_kern_start = newinfo->entries;
2242         state.buf_kern_len = size64;
2243
2244         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2245         BUG_ON(ret < 0);        /* parses same data again */
2246
2247         vfree(entries_tmp);
2248         tmp.entries_size = size64;
2249
2250         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2251                 char __user *usrptr;
2252                 if (tmp.hook_entry[i]) {
2253                         unsigned int delta;
2254                         usrptr = (char __user *) tmp.hook_entry[i];
2255                         delta = usrptr - tmp.entries;
2256                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2257                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2258                 }
2259         }
2260
2261         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2262         xt_compat_unlock(NFPROTO_BRIDGE);
2263
2264         ret = do_replace_finish(net, &tmp, newinfo);
2265         if (ret == 0)
2266                 return ret;
2267 free_entries:
2268         vfree(newinfo->entries);
2269 free_newinfo:
2270         vfree(newinfo);
2271         return ret;
2272 out_unlock:
2273         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2274         xt_compat_unlock(NFPROTO_BRIDGE);
2275         goto free_entries;
2276 }
2277
2278 static int compat_update_counters(struct net *net, void __user *user,
2279                                   unsigned int len)
2280 {
2281         struct compat_ebt_replace hlp;
2282
2283         if (copy_from_user(&hlp, user, sizeof(hlp)))
2284                 return -EFAULT;
2285
2286         /* try real handler in case userland supplied needed padding */
2287         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2288                 return update_counters(net, user, len);
2289
2290         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2291                                         hlp.num_counters, user, len);
2292 }
2293
2294 static int compat_do_ebt_set_ctl(struct sock *sk,
2295                 int cmd, void __user *user, unsigned int len)
2296 {
2297         int ret;
2298         struct net *net = sock_net(sk);
2299
2300         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2301                 return -EPERM;
2302
2303         switch (cmd) {
2304         case EBT_SO_SET_ENTRIES:
2305                 ret = compat_do_replace(net, user, len);
2306                 break;
2307         case EBT_SO_SET_COUNTERS:
2308                 ret = compat_update_counters(net, user, len);
2309                 break;
2310         default:
2311                 ret = -EINVAL;
2312         }
2313         return ret;
2314 }
2315
2316 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2317                 void __user *user, int *len)
2318 {
2319         int ret;
2320         struct compat_ebt_replace tmp;
2321         struct ebt_table *t;
2322         struct net *net = sock_net(sk);
2323
2324         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2325                 return -EPERM;
2326
2327         /* try real handler in case userland supplied needed padding */
2328         if ((cmd == EBT_SO_GET_INFO ||
2329              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2330                         return do_ebt_get_ctl(sk, cmd, user, len);
2331
2332         if (copy_from_user(&tmp, user, sizeof(tmp)))
2333                 return -EFAULT;
2334
2335         tmp.name[sizeof(tmp.name) - 1] = '\0';
2336
2337         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2338         if (!t)
2339                 return ret;
2340
2341         xt_compat_lock(NFPROTO_BRIDGE);
2342         switch (cmd) {
2343         case EBT_SO_GET_INFO:
2344                 tmp.nentries = t->private->nentries;
2345                 ret = compat_table_info(t->private, &tmp);
2346                 if (ret)
2347                         goto out;
2348                 tmp.valid_hooks = t->valid_hooks;
2349
2350                 if (copy_to_user(user, &tmp, *len) != 0) {
2351                         ret = -EFAULT;
2352                         break;
2353                 }
2354                 ret = 0;
2355                 break;
2356         case EBT_SO_GET_INIT_INFO:
2357                 tmp.nentries = t->table->nentries;
2358                 tmp.entries_size = t->table->entries_size;
2359                 tmp.valid_hooks = t->table->valid_hooks;
2360
2361                 if (copy_to_user(user, &tmp, *len) != 0) {
2362                         ret = -EFAULT;
2363                         break;
2364                 }
2365                 ret = 0;
2366                 break;
2367         case EBT_SO_GET_ENTRIES:
2368         case EBT_SO_GET_INIT_ENTRIES:
2369                 /* try real handler first in case of userland-side padding.
2370                  * in case we are dealing with an 'ordinary' 32 bit binary
2371                  * without 64bit compatibility padding, this will fail right
2372                  * after copy_from_user when the *len argument is validated.
2373                  *
2374                  * the compat_ variant needs to do one pass over the kernel
2375                  * data set to adjust for size differences before it the check.
2376                  */
2377                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2378                         ret = 0;
2379                 else
2380                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2381                 break;
2382         default:
2383                 ret = -EINVAL;
2384         }
2385  out:
2386         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2387         xt_compat_unlock(NFPROTO_BRIDGE);
2388         mutex_unlock(&ebt_mutex);
2389         return ret;
2390 }
2391 #endif
2392
2393 static struct nf_sockopt_ops ebt_sockopts = {
2394         .pf             = PF_INET,
2395         .set_optmin     = EBT_BASE_CTL,
2396         .set_optmax     = EBT_SO_SET_MAX + 1,
2397         .set            = do_ebt_set_ctl,
2398 #ifdef CONFIG_COMPAT
2399         .compat_set     = compat_do_ebt_set_ctl,
2400 #endif
2401         .get_optmin     = EBT_BASE_CTL,
2402         .get_optmax     = EBT_SO_GET_MAX + 1,
2403         .get            = do_ebt_get_ctl,
2404 #ifdef CONFIG_COMPAT
2405         .compat_get     = compat_do_ebt_get_ctl,
2406 #endif
2407         .owner          = THIS_MODULE,
2408 };
2409
2410 static int __init ebtables_init(void)
2411 {
2412         int ret;
2413
2414         ret = xt_register_target(&ebt_standard_target);
2415         if (ret < 0)
2416                 return ret;
2417         ret = nf_register_sockopt(&ebt_sockopts);
2418         if (ret < 0) {
2419                 xt_unregister_target(&ebt_standard_target);
2420                 return ret;
2421         }
2422
2423         printk(KERN_INFO "Ebtables v2.0 registered\n");
2424         return 0;
2425 }
2426
2427 static void __exit ebtables_fini(void)
2428 {
2429         nf_unregister_sockopt(&ebt_sockopts);
2430         xt_unregister_target(&ebt_standard_target);
2431         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2432 }
2433
2434 EXPORT_SYMBOL(ebt_register_table);
2435 EXPORT_SYMBOL(ebt_unregister_table);
2436 EXPORT_SYMBOL(ebt_do_table);
2437 module_init(ebtables_init);
2438 module_exit(ebtables_fini);
2439 MODULE_LICENSE("GPL");