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                 ADD_COUNTER(*(counter_base + i), 1, skb->len);
 227
 228                 /* these should only watch: not modify, nor tell us
 229                  * what to do with the packet
 230                  */
 231                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 232
 233                 t = (struct ebt_entry_target *)
 234                    (((char *)point) + point->target_offset);
 235                 /* standard target */
 236                 if (!t->u.target->target)
 237                         verdict = ((struct ebt_standard_target *)t)->verdict;
 238                 else {
 239                         acpar.target   = t->u.target;
 240                         acpar.targinfo = t->data;
 241                         verdict = t->u.target->target(skb, &acpar);
 242                 }
 243                 if (verdict == EBT_ACCEPT) {
 244                         read_unlock_bh(&table->lock);
 245                         return NF_ACCEPT;
 246                 }
 247                 if (verdict == EBT_DROP) {
 248                         read_unlock_bh(&table->lock);
 249                         return NF_DROP;
 250                 }
 251                 if (verdict == EBT_RETURN) {
 252 letsreturn:
 253                         if (WARN(sp == 0, "RETURN on base chain")) {
 254                                 /* act like this is EBT_CONTINUE */
 255                                 goto letscontinue;
 256                         }
 257
 258                         sp--;
 259                         /* put all the local variables right */
 260                         i = cs[sp].n;
 261                         chaininfo = cs[sp].chaininfo;
 262                         nentries = chaininfo->nentries;
 263                         point = cs[sp].e;
 264                         counter_base = cb_base +
 265                            chaininfo->counter_offset;
 266                         continue;
 267                 }
 268                 if (verdict == EBT_CONTINUE)
 269                         goto letscontinue;
 270
 271                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 272                         read_unlock_bh(&table->lock);
 273                         return NF_DROP;
 274                 }
 275
 276                 /* jump to a udc */
 277                 cs[sp].n = i + 1;
 278                 cs[sp].chaininfo = chaininfo;
 279                 cs[sp].e = ebt_next_entry(point);
 280                 i = 0;
 281                 chaininfo = (struct ebt_entries *) (base + verdict);
 282
 283                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 284                         read_unlock_bh(&table->lock);
 285                         return NF_DROP;
 286                 }
 287
 288                 nentries = chaininfo->nentries;
 289                 point = (struct ebt_entry *)chaininfo->data;
 290                 counter_base = cb_base + chaininfo->counter_offset;
 291                 sp++;
 292                 continue;
 293 letscontinue:
 294                 point = ebt_next_entry(point);
 295                 i++;
 296         }
 297
 298         /* I actually like this :) */
 299         if (chaininfo->policy == EBT_RETURN)
 300                 goto letsreturn;
 301         if (chaininfo->policy == EBT_ACCEPT) {
 302                 read_unlock_bh(&table->lock);
 303                 return NF_ACCEPT;
 304         }
 305         read_unlock_bh(&table->lock);
 306         return NF_DROP;
 307 }
 308
 309 /* If it succeeds, returns element and locks mutex */
 310 static inline void *
 311 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 312                         struct mutex *mutex)
 313 {
 314         struct {
 315                 struct list_head list;
 316                 char name[EBT_FUNCTION_MAXNAMELEN];
 317         } *e;
 318
 319         mutex_lock(mutex);
 320         list_for_each_entry(e, head, list) {
 321                 if (strcmp(e->name, name) == 0)
 322                         return e;
 323         }
 324         *error = -ENOENT;
 325         mutex_unlock(mutex);
 326         return NULL;
 327 }
 328
 329 static void *
 330 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 331                  int *error, struct mutex *mutex)
 332 {
 333         return try_then_request_module(
 334                         find_inlist_lock_noload(head, name, error, mutex),
 335                         "%s%s", prefix, name);
 336 }
 337
 338 static inline struct ebt_table *
 339 find_table_lock(struct net *net, const char *name, int *error,
 340                 struct mutex *mutex)
 341 {
 342         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 343                                 "ebtable_", error, mutex);
 344 }
 345
 346 static inline int
 347 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 348                 unsigned int *cnt)
 349 {
 350         const struct ebt_entry *e = par->entryinfo;
 351         struct xt_match *match;
 352         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 353         int ret;
 354
 355         if (left < sizeof(struct ebt_entry_match) ||
 356             left - sizeof(struct ebt_entry_match) < m->match_size)
 357                 return -EINVAL;
 358
 359         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 360         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 361                 if (!IS_ERR(match))
 362                         module_put(match->me);
 363                 request_module("ebt_%s", m->u.name);
 364                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 365         }
 366         if (IS_ERR(match))
 367                 return PTR_ERR(match);
 368         m->u.match = match;
 369
 370         par->match     = match;
 371         par->matchinfo = m->data;
 372         ret = xt_check_match(par, m->match_size,
 373               e->ethproto, e->invflags & EBT_IPROTO);
 374         if (ret < 0) {
 375                 module_put(match->me);
 376                 return ret;
 377         }
 378
 379         (*cnt)++;
 380         return 0;
 381 }
 382
 383 static inline int
 384 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 385                   unsigned int *cnt)
 386 {
 387         const struct ebt_entry *e = par->entryinfo;
 388         struct xt_target *watcher;
 389         size_t left = ((char *)e + e->target_offset) - (char *)w;
 390         int ret;
 391
 392         if (left < sizeof(struct ebt_entry_watcher) ||
 393            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 394                 return -EINVAL;
 395
 396         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 397         if (IS_ERR(watcher))
 398                 return PTR_ERR(watcher);
 399         w->u.watcher = watcher;
 400
 401         par->target   = watcher;
 402         par->targinfo = w->data;
 403         ret = xt_check_target(par, w->watcher_size,
 404               e->ethproto, e->invflags & EBT_IPROTO);
 405         if (ret < 0) {
 406                 module_put(watcher->me);
 407                 return ret;
 408         }
 409
 410         (*cnt)++;
 411         return 0;
 412 }
 413
 414 static int ebt_verify_pointers(const struct ebt_replace *repl,
 415                                struct ebt_table_info *newinfo)
 416 {
 417         unsigned int limit = repl->entries_size;
 418         unsigned int valid_hooks = repl->valid_hooks;
 419         unsigned int offset = 0;
 420         int i;
 421
 422         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 423                 newinfo->hook_entry[i] = NULL;
 424
 425         newinfo->entries_size = repl->entries_size;
 426         newinfo->nentries = repl->nentries;
 427
 428         while (offset < limit) {
 429                 size_t left = limit - offset;
 430                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 431
 432                 if (left < sizeof(unsigned int))
 433                         break;
 434
 435                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 436                         if ((valid_hooks & (1 << i)) == 0)
 437                                 continue;
 438                         if ((char __user *)repl->hook_entry[i] ==
 439                              repl->entries + offset)
 440                                 break;
 441                 }
 442
 443                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 444                         if (e->bitmask != 0) {
 445                                 /* we make userspace set this right,
 446                                  * so there is no misunderstanding
 447                                  */
 448                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 449                                          "in distinguisher\n");
 450                                 return -EINVAL;
 451                         }
 452                         if (i != NF_BR_NUMHOOKS)
 453                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 454                         if (left < sizeof(struct ebt_entries))
 455                                 break;
 456                         offset += sizeof(struct ebt_entries);
 457                 } else {
 458                         if (left < sizeof(struct ebt_entry))
 459                                 break;
 460                         if (left < e->next_offset)
 461                                 break;
 462                         if (e->next_offset < sizeof(struct ebt_entry))
 463                                 return -EINVAL;
 464                         offset += e->next_offset;
 465                 }
 466         }
 467         if (offset != limit) {
 468                 BUGPRINT("entries_size too small\n");
 469                 return -EINVAL;
 470         }
 471
 472         /* check if all valid hooks have a chain */
 473         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 474                 if (!newinfo->hook_entry[i] &&
 475                    (valid_hooks & (1 << i))) {
 476                         BUGPRINT("Valid hook without chain\n");
 477                         return -EINVAL;
 478                 }
 479         }
 480         return 0;
 481 }
 482
 483 /* this one is very careful, as it is the first function
 484  * to parse the userspace data
 485  */
 486 static inline int
 487 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 488                                const struct ebt_table_info *newinfo,
 489                                unsigned int *n, unsigned int *cnt,
 490                                unsigned int *totalcnt, unsigned int *udc_cnt)
 491 {
 492         int i;
 493
 494         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 495                 if ((void *)e == (void *)newinfo->hook_entry[i])
 496                         break;
 497         }
 498         /* beginning of a new chain
 499          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 500          */
 501         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 502                 /* this checks if the previous chain has as many entries
 503                  * as it said it has
 504                  */
 505                 if (*n != *cnt) {
 506                         BUGPRINT("nentries does not equal the nr of entries "
 507                                  "in the chain\n");
 508                         return -EINVAL;
 509                 }
 510                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 511                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 512                         /* only RETURN from udc */
 513                         if (i != NF_BR_NUMHOOKS ||
 514                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 515                                 BUGPRINT("bad policy\n");
 516                                 return -EINVAL;
 517                         }
 518                 }
 519                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 520                         (*udc_cnt)++;
 521                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 522                         BUGPRINT("counter_offset != totalcnt");
 523                         return -EINVAL;
 524                 }
 525                 *n = ((struct ebt_entries *)e)->nentries;
 526                 *cnt = 0;
 527                 return 0;
 528         }
 529         /* a plain old entry, heh */
 530         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 531            e->watchers_offset > e->target_offset ||
 532            e->target_offset >= e->next_offset) {
 533                 BUGPRINT("entry offsets not in right order\n");
 534                 return -EINVAL;
 535         }
 536         /* this is not checked anywhere else */
 537         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 538                 BUGPRINT("target size too small\n");
 539                 return -EINVAL;
 540         }
 541         (*cnt)++;
 542         (*totalcnt)++;
 543         return 0;
 544 }
 545
 546 struct ebt_cl_stack {
 547         struct ebt_chainstack cs;
 548         int from;
 549         unsigned int hookmask;
 550 };
 551
 552 /* We need these positions to check that the jumps to a different part of the
 553  * entries is a jump to the beginning of a new chain.
 554  */
 555 static inline int
 556 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 557                       unsigned int *n, struct ebt_cl_stack *udc)
 558 {
 559         int i;
 560
 561         /* we're only interested in chain starts */
 562         if (e->bitmask)
 563                 return 0;
 564         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 565                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 566                         break;
 567         }
 568         /* only care about udc */
 569         if (i != NF_BR_NUMHOOKS)
 570                 return 0;
 571
 572         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 573         /* these initialisations are depended on later in check_chainloops() */
 574         udc[*n].cs.n = 0;
 575         udc[*n].hookmask = 0;
 576
 577         (*n)++;
 578         return 0;
 579 }
 580
 581 static inline int
 582 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 583 {
 584         struct xt_mtdtor_param par;
 585
 586         if (i && (*i)-- == 0)
 587                 return 1;
 588
 589         par.net       = net;
 590         par.match     = m->u.match;
 591         par.matchinfo = m->data;
 592         par.family    = NFPROTO_BRIDGE;
 593         if (par.match->destroy != NULL)
 594                 par.match->destroy(&par);
 595         module_put(par.match->me);
 596         return 0;
 597 }
 598
 599 static inline int
 600 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 601 {
 602         struct xt_tgdtor_param par;
 603
 604         if (i && (*i)-- == 0)
 605                 return 1;
 606
 607         par.net      = net;
 608         par.target   = w->u.watcher;
 609         par.targinfo = w->data;
 610         par.family   = NFPROTO_BRIDGE;
 611         if (par.target->destroy != NULL)
 612                 par.target->destroy(&par);
 613         module_put(par.target->me);
 614         return 0;
 615 }
 616
 617 static inline int
 618 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 619 {
 620         struct xt_tgdtor_param par;
 621         struct ebt_entry_target *t;
 622
 623         if (e->bitmask == 0)
 624                 return 0;
 625         /* we're done */
 626         if (cnt && (*cnt)-- == 0)
 627                 return 1;
 628         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 629         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 630         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 631
 632         par.net      = net;
 633         par.target   = t->u.target;
 634         par.targinfo = t->data;
 635         par.family   = NFPROTO_BRIDGE;
 636         if (par.target->destroy != NULL)
 637                 par.target->destroy(&par);
 638         module_put(par.target->me);
 639         return 0;
 640 }
 641
 642 static inline int
 643 ebt_check_entry(struct ebt_entry *e, struct net *net,
 644                 const struct ebt_table_info *newinfo,
 645                 const char *name, unsigned int *cnt,
 646                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 647 {
 648         struct ebt_entry_target *t;
 649         struct xt_target *target;
 650         unsigned int i, j, hook = 0, hookmask = 0;
 651         size_t gap;
 652         int ret;
 653         struct xt_mtchk_param mtpar;
 654         struct xt_tgchk_param tgpar;
 655
 656         /* don't mess with the struct ebt_entries */
 657         if (e->bitmask == 0)
 658                 return 0;
 659
 660         if (e->bitmask & ~EBT_F_MASK) {
 661                 BUGPRINT("Unknown flag for bitmask\n");
 662                 return -EINVAL;
 663         }
 664         if (e->invflags & ~EBT_INV_MASK) {
 665                 BUGPRINT("Unknown flag for inv bitmask\n");
 666                 return -EINVAL;
 667         }
 668         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 669                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 670                 return -EINVAL;
 671         }
 672         /* what hook do we belong to? */
 673         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 674                 if (!newinfo->hook_entry[i])
 675                         continue;
 676                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 677                         hook = i;
 678                 else
 679                         break;
 680         }
 681         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 682          * a base chain
 683          */
 684         if (i < NF_BR_NUMHOOKS)
 685                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 686         else {
 687                 for (i = 0; i < udc_cnt; i++)
 688                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 689                                 break;
 690                 if (i == 0)
 691                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 692                 else
 693                         hookmask = cl_s[i - 1].hookmask;
 694         }
 695         i = 0;
 696
 697         mtpar.net       = tgpar.net       = net;
 698         mtpar.table     = tgpar.table     = name;
 699         mtpar.entryinfo = tgpar.entryinfo = e;
 700         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 701         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 702         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 703         if (ret != 0)
 704                 goto cleanup_matches;
 705         j = 0;
 706         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 707         if (ret != 0)
 708                 goto cleanup_watchers;
 709         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 710         gap = e->next_offset - e->target_offset;
 711
 712         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 713         if (IS_ERR(target)) {
 714                 ret = PTR_ERR(target);
 715                 goto cleanup_watchers;
 716         }
 717
 718         t->u.target = target;
 719         if (t->u.target == &ebt_standard_target) {
 720                 if (gap < sizeof(struct ebt_standard_target)) {
 721                         BUGPRINT("Standard target size too big\n");
 722                         ret = -EFAULT;
 723                         goto cleanup_watchers;
 724                 }
 725                 if (((struct ebt_standard_target *)t)->verdict <
 726                    -NUM_STANDARD_TARGETS) {
 727                         BUGPRINT("Invalid standard target\n");
 728                         ret = -EFAULT;
 729                         goto cleanup_watchers;
 730                 }
 731         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 732                 module_put(t->u.target->me);
 733                 ret = -EFAULT;
 734                 goto cleanup_watchers;
 735         }
 736
 737         tgpar.target   = target;
 738         tgpar.targinfo = t->data;
 739         ret = xt_check_target(&tgpar, t->target_size,
 740               e->ethproto, e->invflags & EBT_IPROTO);
 741         if (ret < 0) {
 742                 module_put(target->me);
 743                 goto cleanup_watchers;
 744         }
 745         (*cnt)++;
 746         return 0;
 747 cleanup_watchers:
 748         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 749 cleanup_matches:
 750         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 751         return ret;
 752 }
 753
 754 /* checks for loops and sets the hook mask for udc
 755  * the hook mask for udc tells us from which base chains the udc can be
 756  * accessed. This mask is a parameter to the check() functions of the extensions
 757  */
 758 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 759                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 760 {
 761         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 762         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 763         const struct ebt_entry_target *t;
 764
 765         while (pos < nentries || chain_nr != -1) {
 766                 /* end of udc, go back one 'recursion' step */
 767                 if (pos == nentries) {
 768                         /* put back values of the time when this chain was called */
 769                         e = cl_s[chain_nr].cs.e;
 770                         if (cl_s[chain_nr].from != -1)
 771                                 nentries =
 772                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 773                         else
 774                                 nentries = chain->nentries;
 775                         pos = cl_s[chain_nr].cs.n;
 776                         /* make sure we won't see a loop that isn't one */
 777                         cl_s[chain_nr].cs.n = 0;
 778                         chain_nr = cl_s[chain_nr].from;
 779                         if (pos == nentries)
 780                                 continue;
 781                 }
 782                 t = (struct ebt_entry_target *)
 783                    (((char *)e) + e->target_offset);
 784                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 785                         goto letscontinue;
 786                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 787                    e->next_offset) {
 788                         BUGPRINT("Standard target size too big\n");
 789                         return -1;
 790                 }
 791                 verdict = ((struct ebt_standard_target *)t)->verdict;
 792                 if (verdict >= 0) { /* jump to another chain */
 793                         struct ebt_entries *hlp2 =
 794                            (struct ebt_entries *)(base + verdict);
 795                         for (i = 0; i < udc_cnt; i++)
 796                                 if (hlp2 == cl_s[i].cs.chaininfo)
 797                                         break;
 798                         /* bad destination or loop */
 799                         if (i == udc_cnt) {
 800                                 BUGPRINT("bad destination\n");
 801                                 return -1;
 802                         }
 803                         if (cl_s[i].cs.n) {
 804                                 BUGPRINT("loop\n");
 805                                 return -1;
 806                         }
 807                         if (cl_s[i].hookmask & (1 << hooknr))
 808                                 goto letscontinue;
 809                         /* this can't be 0, so the loop test is correct */
 810                         cl_s[i].cs.n = pos + 1;
 811                         pos = 0;
 812                         cl_s[i].cs.e = ebt_next_entry(e);
 813                         e = (struct ebt_entry *)(hlp2->data);
 814                         nentries = hlp2->nentries;
 815                         cl_s[i].from = chain_nr;
 816                         chain_nr = i;
 817                         /* this udc is accessible from the base chain for hooknr */
 818                         cl_s[i].hookmask |= (1 << hooknr);
 819                         continue;
 820                 }
 821 letscontinue:
 822                 e = ebt_next_entry(e);
 823                 pos++;
 824         }
 825         return 0;
 826 }
 827
 828 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 829 static int translate_table(struct net *net, const char *name,
 830                            struct ebt_table_info *newinfo)
 831 {
 832         unsigned int i, j, k, udc_cnt;
 833         int ret;
 834         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 835
 836         i = 0;
 837         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 838                 i++;
 839         if (i == NF_BR_NUMHOOKS) {
 840                 BUGPRINT("No valid hooks specified\n");
 841                 return -EINVAL;
 842         }
 843         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 844                 BUGPRINT("Chains don't start at beginning\n");
 845                 return -EINVAL;
 846         }
 847         /* make sure chains are ordered after each other in same order
 848          * as their corresponding hooks
 849          */
 850         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 851                 if (!newinfo->hook_entry[j])
 852                         continue;
 853                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 854                         BUGPRINT("Hook order must be followed\n");
 855                         return -EINVAL;
 856                 }
 857                 i = j;
 858         }
 859
 860         /* do some early checkings and initialize some things */
 861         i = 0; /* holds the expected nr. of entries for the chain */
 862         j = 0; /* holds the up to now counted entries for the chain */
 863         k = 0; /* holds the total nr. of entries, should equal
 864                 * newinfo->nentries afterwards
 865                 */
 866         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 867         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 868            ebt_check_entry_size_and_hooks, newinfo,
 869            &i, &j, &k, &udc_cnt);
 870
 871         if (ret != 0)
 872                 return ret;
 873
 874         if (i != j) {
 875                 BUGPRINT("nentries does not equal the nr of entries in the "
 876                          "(last) chain\n");
 877                 return -EINVAL;
 878         }
 879         if (k != newinfo->nentries) {
 880                 BUGPRINT("Total nentries is wrong\n");
 881                 return -EINVAL;
 882         }
 883
 884         /* get the location of the udc, put them in an array
 885          * while we're at it, allocate the chainstack
 886          */
 887         if (udc_cnt) {
 888                 /* this will get free'd in do_replace()/ebt_register_table()
 889                  * if an error occurs
 890                  */
 891                 newinfo->chainstack =
 892                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 893                 if (!newinfo->chainstack)
 894                         return -ENOMEM;
 895                 for_each_possible_cpu(i) {
 896                         newinfo->chainstack[i] =
 897                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 898                         if (!newinfo->chainstack[i]) {
 899                                 while (i)
 900                                         vfree(newinfo->chainstack[--i]);
 901                                 vfree(newinfo->chainstack);
 902                                 newinfo->chainstack = NULL;
 903                                 return -ENOMEM;
 904                         }
 905                 }
 906
 907                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 908                 if (!cl_s)
 909                         return -ENOMEM;
 910                 i = 0; /* the i'th udc */
 911                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 912                    ebt_get_udc_positions, newinfo, &i, cl_s);
 913                 /* sanity check */
 914                 if (i != udc_cnt) {
 915                         BUGPRINT("i != udc_cnt\n");
 916                         vfree(cl_s);
 917                         return -EFAULT;
 918                 }
 919         }
 920
 921         /* Check for loops */
 922         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 923                 if (newinfo->hook_entry[i])
 924                         if (check_chainloops(newinfo->hook_entry[i],
 925                            cl_s, udc_cnt, i, newinfo->entries)) {
 926                                 vfree(cl_s);
 927                                 return -EINVAL;
 928                         }
 929
 930         /* we now know the following (along with E=mc²):
 931          *  - the nr of entries in each chain is right
 932          *  - the size of the allocated space is right
 933          *  - all valid hooks have a corresponding chain
 934          *  - there are no loops
 935          *  - wrong data can still be on the level of a single entry
 936          *  - could be there are jumps to places that are not the
 937          *    beginning of a chain. This can only occur in chains that
 938          *    are not accessible from any base chains, so we don't care.
 939          */
 940
 941         /* used to know what we need to clean up if something goes wrong */
 942         i = 0;
 943         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 944            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 945         if (ret != 0) {
 946                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 947                                   ebt_cleanup_entry, net, &i);
 948         }
 949         vfree(cl_s);
 950         return ret;
 951 }
 952
 953 /* called under write_lock */
 954 static void get_counters(const struct ebt_counter *oldcounters,
 955                          struct ebt_counter *counters, unsigned int nentries)
 956 {
 957         int i, cpu;
 958         struct ebt_counter *counter_base;
 959
 960         /* counters of cpu 0 */
 961         memcpy(counters, oldcounters,
 962                sizeof(struct ebt_counter) * nentries);
 963
 964         /* add other counters to those of cpu 0 */
 965         for_each_possible_cpu(cpu) {
 966                 if (cpu == 0)
 967                         continue;
 968                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 969                 for (i = 0; i < nentries; i++)
 970                         ADD_COUNTER(counters[i], counter_base[i].pcnt,
 971                                     counter_base[i].bcnt);
 972         }
 973 }
 974
 975 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 976                               struct ebt_table_info *newinfo)
 977 {
 978         int ret, i;
 979         struct ebt_counter *counterstmp = NULL;
 980         /* used to be able to unlock earlier */
 981         struct ebt_table_info *table;
 982         struct ebt_table *t;
 983
 984         /* the user wants counters back
 985          * the check on the size is done later, when we have the lock
 986          */
 987         if (repl->num_counters) {
 988                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 989                 counterstmp = vmalloc(size);
 990                 if (!counterstmp)
 991                         return -ENOMEM;
 992         }
 993
 994         newinfo->chainstack = NULL;
 995         ret = ebt_verify_pointers(repl, newinfo);
 996         if (ret != 0)
 997                 goto free_counterstmp;
 998
 999         ret = translate_table(net, repl->name, newinfo);
1000
1001         if (ret != 0)
1002                 goto free_counterstmp;
1003
1004         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1005         if (!t) {
1006                 ret = -ENOENT;
1007                 goto free_iterate;
1008         }
1009
1010         /* the table doesn't like it */
1011         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1012                 goto free_unlock;
1013
1014         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1015                 BUGPRINT("Wrong nr. of counters requested\n");
1016                 ret = -EINVAL;
1017                 goto free_unlock;
1018         }
1019
1020         /* we have the mutex lock, so no danger in reading this pointer */
1021         table = t->private;
1022         /* make sure the table can only be rmmod'ed if it contains no rules */
1023         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1024                 ret = -ENOENT;
1025                 goto free_unlock;
1026         } else if (table->nentries && !newinfo->nentries)
1027                 module_put(t->me);
1028         /* we need an atomic snapshot of the counters */
1029         write_lock_bh(&t->lock);
1030         if (repl->num_counters)
1031                 get_counters(t->private->counters, counterstmp,
1032                    t->private->nentries);
1033
1034         t->private = newinfo;
1035         write_unlock_bh(&t->lock);
1036         mutex_unlock(&ebt_mutex);
1037         /* so, a user can change the chains while having messed up her counter
1038          * allocation. Only reason why this is done is because this way the lock
1039          * is held only once, while this doesn't bring the kernel into a
1040          * dangerous state.
1041          */
1042         if (repl->num_counters &&
1043            copy_to_user(repl->counters, counterstmp,
1044            repl->num_counters * sizeof(struct ebt_counter))) {
1045                 /* Silent error, can't fail, new table is already in place */
1046                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1047         }
1048
1049         /* decrease module count and free resources */
1050         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1051                           ebt_cleanup_entry, net, NULL);
1052
1053         vfree(table->entries);
1054         if (table->chainstack) {
1055                 for_each_possible_cpu(i)
1056                         vfree(table->chainstack[i]);
1057                 vfree(table->chainstack);
1058         }
1059         vfree(table);
1060
1061         vfree(counterstmp);
1062
1063 #ifdef CONFIG_AUDIT
1064         if (audit_enabled) {
1065                 audit_log(current->audit_context, GFP_KERNEL,
1066                           AUDIT_NETFILTER_CFG,
1067                           "table=%s family=%u entries=%u",
1068                           repl->name, AF_BRIDGE, repl->nentries);
1069         }
1070 #endif
1071         return ret;
1072
1073 free_unlock:
1074         mutex_unlock(&ebt_mutex);
1075 free_iterate:
1076         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1077                           ebt_cleanup_entry, net, NULL);
1078 free_counterstmp:
1079         vfree(counterstmp);
1080         /* can be initialized in translate_table() */
1081         if (newinfo->chainstack) {
1082                 for_each_possible_cpu(i)
1083                         vfree(newinfo->chainstack[i]);
1084                 vfree(newinfo->chainstack);
1085         }
1086         return ret;
1087 }
1088
1089 /* replace the table */
1090 static int do_replace(struct net *net, const void __user *user,
1091                       unsigned int len)
1092 {
1093         int ret, countersize;
1094         struct ebt_table_info *newinfo;
1095         struct ebt_replace tmp;
1096
1097         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1098                 return -EFAULT;
1099
1100         if (len != sizeof(tmp) + tmp.entries_size) {
1101                 BUGPRINT("Wrong len argument\n");
1102                 return -EINVAL;
1103         }
1104
1105         if (tmp.entries_size == 0) {
1106                 BUGPRINT("Entries_size never zero\n");
1107                 return -EINVAL;
1108         }
1109         /* overflow check */
1110         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1111                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1112                 return -ENOMEM;
1113         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1114                 return -ENOMEM;
1115
1116         tmp.name[sizeof(tmp.name) - 1] = 0;
1117
1118         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1119         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1120         if (!newinfo)
1121                 return -ENOMEM;
1122
1123         if (countersize)
1124                 memset(newinfo->counters, 0, countersize);
1125
1126         newinfo->entries = vmalloc(tmp.entries_size);
1127         if (!newinfo->entries) {
1128                 ret = -ENOMEM;
1129                 goto free_newinfo;
1130         }
1131         if (copy_from_user(
1132            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1133                 BUGPRINT("Couldn't copy entries from userspace\n");
1134                 ret = -EFAULT;
1135                 goto free_entries;
1136         }
1137
1138         ret = do_replace_finish(net, &tmp, newinfo);
1139         if (ret == 0)
1140                 return ret;
1141 free_entries:
1142         vfree(newinfo->entries);
1143 free_newinfo:
1144         vfree(newinfo);
1145         return ret;
1146 }
1147
1148 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1149 {
1150         int i;
1151
1152         mutex_lock(&ebt_mutex);
1153         list_del(&table->list);
1154         mutex_unlock(&ebt_mutex);
1155         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1156                           ebt_cleanup_entry, net, NULL);
1157         if (table->private->nentries)
1158                 module_put(table->me);
1159         vfree(table->private->entries);
1160         if (table->private->chainstack) {
1161                 for_each_possible_cpu(i)
1162                         vfree(table->private->chainstack[i]);
1163                 vfree(table->private->chainstack);
1164         }
1165         vfree(table->private);
1166         kfree(table);
1167 }
1168
1169 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1170                        const struct nf_hook_ops *ops, struct ebt_table **res)
1171 {
1172         struct ebt_table_info *newinfo;
1173         struct ebt_table *t, *table;
1174         struct ebt_replace_kernel *repl;
1175         int ret, i, countersize;
1176         void *p;
1177
1178         if (input_table == NULL || (repl = input_table->table) == NULL ||
1179             repl->entries == NULL || repl->entries_size == 0 ||
1180             repl->counters != NULL || input_table->private != NULL) {
1181                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1182                 return -EINVAL;
1183         }
1184
1185         /* Don't add one table to multiple lists. */
1186         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1187         if (!table) {
1188                 ret = -ENOMEM;
1189                 goto out;
1190         }
1191
1192         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1193         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1194         ret = -ENOMEM;
1195         if (!newinfo)
1196                 goto free_table;
1197
1198         p = vmalloc(repl->entries_size);
1199         if (!p)
1200                 goto free_newinfo;
1201
1202         memcpy(p, repl->entries, repl->entries_size);
1203         newinfo->entries = p;
1204
1205         newinfo->entries_size = repl->entries_size;
1206         newinfo->nentries = repl->nentries;
1207
1208         if (countersize)
1209                 memset(newinfo->counters, 0, countersize);
1210
1211         /* fill in newinfo and parse the entries */
1212         newinfo->chainstack = NULL;
1213         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1214                 if ((repl->valid_hooks & (1 << i)) == 0)
1215                         newinfo->hook_entry[i] = NULL;
1216                 else
1217                         newinfo->hook_entry[i] = p +
1218                                 ((char *)repl->hook_entry[i] - repl->entries);
1219         }
1220         ret = translate_table(net, repl->name, newinfo);
1221         if (ret != 0) {
1222                 BUGPRINT("Translate_table failed\n");
1223                 goto free_chainstack;
1224         }
1225
1226         if (table->check && table->check(newinfo, table->valid_hooks)) {
1227                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1228                 ret = -EINVAL;
1229                 goto free_chainstack;
1230         }
1231
1232         table->private = newinfo;
1233         rwlock_init(&table->lock);
1234         mutex_lock(&ebt_mutex);
1235         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1236                 if (strcmp(t->name, table->name) == 0) {
1237                         ret = -EEXIST;
1238                         BUGPRINT("Table name already exists\n");
1239                         goto free_unlock;
1240                 }
1241         }
1242
1243         /* Hold a reference count if the chains aren't empty */
1244         if (newinfo->nentries && !try_module_get(table->me)) {
1245                 ret = -ENOENT;
1246                 goto free_unlock;
1247         }
1248         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1249         mutex_unlock(&ebt_mutex);
1250
1251         WRITE_ONCE(*res, table);
1252
1253         if (!ops)
1254                 return 0;
1255
1256         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1257         if (ret) {
1258                 __ebt_unregister_table(net, table);
1259                 *res = NULL;
1260         }
1261
1262         return ret;
1263 free_unlock:
1264         mutex_unlock(&ebt_mutex);
1265 free_chainstack:
1266         if (newinfo->chainstack) {
1267                 for_each_possible_cpu(i)
1268                         vfree(newinfo->chainstack[i]);
1269                 vfree(newinfo->chainstack);
1270         }
1271         vfree(newinfo->entries);
1272 free_newinfo:
1273         vfree(newinfo);
1274 free_table:
1275         kfree(table);
1276 out:
1277         return ret;
1278 }
1279
1280 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1281                           const struct nf_hook_ops *ops)
1282 {
1283         if (ops)
1284                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1285         __ebt_unregister_table(net, table);
1286 }
1287
1288 /* userspace just supplied us with counters */
1289 static int do_update_counters(struct net *net, const char *name,
1290                                 struct ebt_counter __user *counters,
1291                                 unsigned int num_counters,
1292                                 const void __user *user, unsigned int len)
1293 {
1294         int i, ret;
1295         struct ebt_counter *tmp;
1296         struct ebt_table *t;
1297
1298         if (num_counters == 0)
1299                 return -EINVAL;
1300
1301         tmp = vmalloc(num_counters * sizeof(*tmp));
1302         if (!tmp)
1303                 return -ENOMEM;
1304
1305         t = find_table_lock(net, name, &ret, &ebt_mutex);
1306         if (!t)
1307                 goto free_tmp;
1308
1309         if (num_counters != t->private->nentries) {
1310                 BUGPRINT("Wrong nr of counters\n");
1311                 ret = -EINVAL;
1312                 goto unlock_mutex;
1313         }
1314
1315         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1316                 ret = -EFAULT;
1317                 goto unlock_mutex;
1318         }
1319
1320         /* we want an atomic add of the counters */
1321         write_lock_bh(&t->lock);
1322
1323         /* we add to the counters of the first cpu */
1324         for (i = 0; i < num_counters; i++)
1325                 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt);
1326
1327         write_unlock_bh(&t->lock);
1328         ret = 0;
1329 unlock_mutex:
1330         mutex_unlock(&ebt_mutex);
1331 free_tmp:
1332         vfree(tmp);
1333         return ret;
1334 }
1335
1336 static int update_counters(struct net *net, const void __user *user,
1337                             unsigned int len)
1338 {
1339         struct ebt_replace hlp;
1340
1341         if (copy_from_user(&hlp, user, sizeof(hlp)))
1342                 return -EFAULT;
1343
1344         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1345                 return -EINVAL;
1346
1347         return do_update_counters(net, hlp.name, hlp.counters,
1348                                 hlp.num_counters, user, len);
1349 }
1350
1351 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1352                                   const char *data, int entrysize,
1353                                   int usersize, int datasize, u8 revision)
1354 {
1355         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1356
1357         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1358          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1359          */
1360         strlcpy(name, _name, sizeof(name));
1361         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1362             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1363             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1364             xt_data_to_user(um + entrysize, data, usersize, datasize,
1365                             XT_ALIGN(datasize)))
1366                 return -EFAULT;
1367
1368         return 0;
1369 }
1370
1371 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1372                                     const char *base, char __user *ubase)
1373 {
1374         return ebt_obj_to_user(ubase + ((char *)m - base),
1375                                m->u.match->name, m->data, sizeof(*m),
1376                                m->u.match->usersize, m->match_size,
1377                                m->u.match->revision);
1378 }
1379
1380 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1381                                       const char *base, char __user *ubase)
1382 {
1383         return ebt_obj_to_user(ubase + ((char *)w - base),
1384                                w->u.watcher->name, w->data, sizeof(*w),
1385                                w->u.watcher->usersize, w->watcher_size,
1386                                w->u.watcher->revision);
1387 }
1388
1389 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1390                                     char __user *ubase)
1391 {
1392         int ret;
1393         char __user *hlp;
1394         const struct ebt_entry_target *t;
1395
1396         if (e->bitmask == 0) {
1397                 /* special case !EBT_ENTRY_OR_ENTRIES */
1398                 if (copy_to_user(ubase + ((char *)e - base), e,
1399                                  sizeof(struct ebt_entries)))
1400                         return -EFAULT;
1401                 return 0;
1402         }
1403
1404         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1405                 return -EFAULT;
1406
1407         hlp = ubase + (((char *)e + e->target_offset) - base);
1408         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1409
1410         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1411         if (ret != 0)
1412                 return ret;
1413         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1414         if (ret != 0)
1415                 return ret;
1416         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1417                               t->u.target->usersize, t->target_size,
1418                               t->u.target->revision);
1419         if (ret != 0)
1420                 return ret;
1421
1422         return 0;
1423 }
1424
1425 static int copy_counters_to_user(struct ebt_table *t,
1426                                  const struct ebt_counter *oldcounters,
1427                                  void __user *user, unsigned int num_counters,
1428                                  unsigned int nentries)
1429 {
1430         struct ebt_counter *counterstmp;
1431         int ret = 0;
1432
1433         /* userspace might not need the counters */
1434         if (num_counters == 0)
1435                 return 0;
1436
1437         if (num_counters != nentries) {
1438                 BUGPRINT("Num_counters wrong\n");
1439                 return -EINVAL;
1440         }
1441
1442         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1443         if (!counterstmp)
1444                 return -ENOMEM;
1445
1446         write_lock_bh(&t->lock);
1447         get_counters(oldcounters, counterstmp, nentries);
1448         write_unlock_bh(&t->lock);
1449
1450         if (copy_to_user(user, counterstmp,
1451            nentries * sizeof(struct ebt_counter)))
1452                 ret = -EFAULT;
1453         vfree(counterstmp);
1454         return ret;
1455 }
1456
1457 /* called with ebt_mutex locked */
1458 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1459                                    const int *len, int cmd)
1460 {
1461         struct ebt_replace tmp;
1462         const struct ebt_counter *oldcounters;
1463         unsigned int entries_size, nentries;
1464         int ret;
1465         char *entries;
1466
1467         if (cmd == EBT_SO_GET_ENTRIES) {
1468                 entries_size = t->private->entries_size;
1469                 nentries = t->private->nentries;
1470                 entries = t->private->entries;
1471                 oldcounters = t->private->counters;
1472         } else {
1473                 entries_size = t->table->entries_size;
1474                 nentries = t->table->nentries;
1475                 entries = t->table->entries;
1476                 oldcounters = t->table->counters;
1477         }
1478
1479         if (copy_from_user(&tmp, user, sizeof(tmp)))
1480                 return -EFAULT;
1481
1482         if (*len != sizeof(struct ebt_replace) + entries_size +
1483            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1484                 return -EINVAL;
1485
1486         if (tmp.nentries != nentries) {
1487                 BUGPRINT("Nentries wrong\n");
1488                 return -EINVAL;
1489         }
1490
1491         if (tmp.entries_size != entries_size) {
1492                 BUGPRINT("Wrong size\n");
1493                 return -EINVAL;
1494         }
1495
1496         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1497                                         tmp.num_counters, nentries);
1498         if (ret)
1499                 return ret;
1500
1501         /* set the match/watcher/target names right */
1502         return EBT_ENTRY_ITERATE(entries, entries_size,
1503            ebt_entry_to_user, entries, tmp.entries);
1504 }
1505
1506 static int do_ebt_set_ctl(struct sock *sk,
1507         int cmd, void __user *user, unsigned int len)
1508 {
1509         int ret;
1510         struct net *net = sock_net(sk);
1511
1512         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1513                 return -EPERM;
1514
1515         switch (cmd) {
1516         case EBT_SO_SET_ENTRIES:
1517                 ret = do_replace(net, user, len);
1518                 break;
1519         case EBT_SO_SET_COUNTERS:
1520                 ret = update_counters(net, user, len);
1521                 break;
1522         default:
1523                 ret = -EINVAL;
1524         }
1525         return ret;
1526 }
1527
1528 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1529 {
1530         int ret;
1531         struct ebt_replace tmp;
1532         struct ebt_table *t;
1533         struct net *net = sock_net(sk);
1534
1535         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1536                 return -EPERM;
1537
1538         if (copy_from_user(&tmp, user, sizeof(tmp)))
1539                 return -EFAULT;
1540
1541         tmp.name[sizeof(tmp.name) - 1] = '\0';
1542
1543         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1544         if (!t)
1545                 return ret;
1546
1547         switch (cmd) {
1548         case EBT_SO_GET_INFO:
1549         case EBT_SO_GET_INIT_INFO:
1550                 if (*len != sizeof(struct ebt_replace)) {
1551                         ret = -EINVAL;
1552                         mutex_unlock(&ebt_mutex);
1553                         break;
1554                 }
1555                 if (cmd == EBT_SO_GET_INFO) {
1556                         tmp.nentries = t->private->nentries;
1557                         tmp.entries_size = t->private->entries_size;
1558                         tmp.valid_hooks = t->valid_hooks;
1559                 } else {
1560                         tmp.nentries = t->table->nentries;
1561                         tmp.entries_size = t->table->entries_size;
1562                         tmp.valid_hooks = t->table->valid_hooks;
1563                 }
1564                 mutex_unlock(&ebt_mutex);
1565                 if (copy_to_user(user, &tmp, *len) != 0) {
1566                         BUGPRINT("c2u Didn't work\n");
1567                         ret = -EFAULT;
1568                         break;
1569                 }
1570                 ret = 0;
1571                 break;
1572
1573         case EBT_SO_GET_ENTRIES:
1574         case EBT_SO_GET_INIT_ENTRIES:
1575                 ret = copy_everything_to_user(t, user, len, cmd);
1576                 mutex_unlock(&ebt_mutex);
1577                 break;
1578
1579         default:
1580                 mutex_unlock(&ebt_mutex);
1581                 ret = -EINVAL;
1582         }
1583
1584         return ret;
1585 }
1586
1587 #ifdef CONFIG_COMPAT
1588 /* 32 bit-userspace compatibility definitions. */
1589 struct compat_ebt_replace {
1590         char name[EBT_TABLE_MAXNAMELEN];
1591         compat_uint_t valid_hooks;
1592         compat_uint_t nentries;
1593         compat_uint_t entries_size;
1594         /* start of the chains */
1595         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1596         /* nr of counters userspace expects back */
1597         compat_uint_t num_counters;
1598         /* where the kernel will put the old counters. */
1599         compat_uptr_t counters;
1600         compat_uptr_t entries;
1601 };
1602
1603 /* struct ebt_entry_match, _target and _watcher have same layout */
1604 struct compat_ebt_entry_mwt {
1605         union {
1606                 struct {
1607                         char name[EBT_EXTENSION_MAXNAMELEN];
1608                         u8 revision;
1609                 };
1610                 compat_uptr_t ptr;
1611         } u;
1612         compat_uint_t match_size;
1613         compat_uint_t data[0];
1614 };
1615
1616 /* account for possible padding between match_size and ->data */
1617 static int ebt_compat_entry_padsize(void)
1618 {
1619         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1620                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1621         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1622                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1623 }
1624
1625 static int ebt_compat_match_offset(const struct xt_match *match,
1626                                    unsigned int userlen)
1627 {
1628         /* ebt_among needs special handling. The kernel .matchsize is
1629          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1630          * value is expected.
1631          * Example: userspace sends 4500, ebt_among.c wants 4504.
1632          */
1633         if (unlikely(match->matchsize == -1))
1634                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1635         return xt_compat_match_offset(match);
1636 }
1637
1638 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1639                                 unsigned int *size)
1640 {
1641         const struct xt_match *match = m->u.match;
1642         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1643         int off = ebt_compat_match_offset(match, m->match_size);
1644         compat_uint_t msize = m->match_size - off;
1645
1646         if (WARN_ON(off >= m->match_size))
1647                 return -EINVAL;
1648
1649         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1650             put_user(match->revision, &cm->u.revision) ||
1651             put_user(msize, &cm->match_size))
1652                 return -EFAULT;
1653
1654         if (match->compat_to_user) {
1655                 if (match->compat_to_user(cm->data, m->data))
1656                         return -EFAULT;
1657         } else {
1658                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1659                                     COMPAT_XT_ALIGN(msize)))
1660                         return -EFAULT;
1661         }
1662
1663         *size -= ebt_compat_entry_padsize() + off;
1664         *dstptr = cm->data;
1665         *dstptr += msize;
1666         return 0;
1667 }
1668
1669 static int compat_target_to_user(struct ebt_entry_target *t,
1670                                  void __user **dstptr,
1671                                  unsigned int *size)
1672 {
1673         const struct xt_target *target = t->u.target;
1674         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1675         int off = xt_compat_target_offset(target);
1676         compat_uint_t tsize = t->target_size - off;
1677
1678         if (WARN_ON(off >= t->target_size))
1679                 return -EINVAL;
1680
1681         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1682             put_user(target->revision, &cm->u.revision) ||
1683             put_user(tsize, &cm->match_size))
1684                 return -EFAULT;
1685
1686         if (target->compat_to_user) {
1687                 if (target->compat_to_user(cm->data, t->data))
1688                         return -EFAULT;
1689         } else {
1690                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1691                                     COMPAT_XT_ALIGN(tsize)))
1692                         return -EFAULT;
1693         }
1694
1695         *size -= ebt_compat_entry_padsize() + off;
1696         *dstptr = cm->data;
1697         *dstptr += tsize;
1698         return 0;
1699 }
1700
1701 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1702                                   void __user **dstptr,
1703                                   unsigned int *size)
1704 {
1705         return compat_target_to_user((struct ebt_entry_target *)w,
1706                                                         dstptr, size);
1707 }
1708
1709 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1710                                 unsigned int *size)
1711 {
1712         struct ebt_entry_target *t;
1713         struct ebt_entry __user *ce;
1714         u32 watchers_offset, target_offset, next_offset;
1715         compat_uint_t origsize;
1716         int ret;
1717
1718         if (e->bitmask == 0) {
1719                 if (*size < sizeof(struct ebt_entries))
1720                         return -EINVAL;
1721                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1722                         return -EFAULT;
1723
1724                 *dstptr += sizeof(struct ebt_entries);
1725                 *size -= sizeof(struct ebt_entries);
1726                 return 0;
1727         }
1728
1729         if (*size < sizeof(*ce))
1730                 return -EINVAL;
1731
1732         ce = *dstptr;
1733         if (copy_to_user(ce, e, sizeof(*ce)))
1734                 return -EFAULT;
1735
1736         origsize = *size;
1737         *dstptr += sizeof(*ce);
1738
1739         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1740         if (ret)
1741                 return ret;
1742         watchers_offset = e->watchers_offset - (origsize - *size);
1743
1744         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1745         if (ret)
1746                 return ret;
1747         target_offset = e->target_offset - (origsize - *size);
1748
1749         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1750
1751         ret = compat_target_to_user(t, dstptr, size);
1752         if (ret)
1753                 return ret;
1754         next_offset = e->next_offset - (origsize - *size);
1755
1756         if (put_user(watchers_offset, &ce->watchers_offset) ||
1757             put_user(target_offset, &ce->target_offset) ||
1758             put_user(next_offset, &ce->next_offset))
1759                 return -EFAULT;
1760
1761         *size -= sizeof(*ce);
1762         return 0;
1763 }
1764
1765 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1766 {
1767         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1768         *off += ebt_compat_entry_padsize();
1769         return 0;
1770 }
1771
1772 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1773 {
1774         *off += xt_compat_target_offset(w->u.watcher);
1775         *off += ebt_compat_entry_padsize();
1776         return 0;
1777 }
1778
1779 static int compat_calc_entry(const struct ebt_entry *e,
1780                              const struct ebt_table_info *info,
1781                              const void *base,
1782                              struct compat_ebt_replace *newinfo)
1783 {
1784         const struct ebt_entry_target *t;
1785         unsigned int entry_offset;
1786         int off, ret, i;
1787
1788         if (e->bitmask == 0)
1789                 return 0;
1790
1791         off = 0;
1792         entry_offset = (void *)e - base;
1793
1794         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1795         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1796
1797         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1798
1799         off += xt_compat_target_offset(t->u.target);
1800         off += ebt_compat_entry_padsize();
1801
1802         newinfo->entries_size -= off;
1803
1804         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1805         if (ret)
1806                 return ret;
1807
1808         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1809                 const void *hookptr = info->hook_entry[i];
1810                 if (info->hook_entry[i] &&
1811                     (e < (struct ebt_entry *)(base - hookptr))) {
1812                         newinfo->hook_entry[i] -= off;
1813                         pr_debug("0x%08X -> 0x%08X\n",
1814                                         newinfo->hook_entry[i] + off,
1815                                         newinfo->hook_entry[i]);
1816                 }
1817         }
1818
1819         return 0;
1820 }
1821
1822
1823 static int compat_table_info(const struct ebt_table_info *info,
1824                              struct compat_ebt_replace *newinfo)
1825 {
1826         unsigned int size = info->entries_size;
1827         const void *entries = info->entries;
1828
1829         newinfo->entries_size = size;
1830         if (info->nentries) {
1831                 int ret = xt_compat_init_offsets(NFPROTO_BRIDGE,
1832                                                  info->nentries);
1833                 if (ret)
1834                         return ret;
1835         }
1836
1837         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1838                                                         entries, newinfo);
1839 }
1840
1841 static int compat_copy_everything_to_user(struct ebt_table *t,
1842                                           void __user *user, int *len, int cmd)
1843 {
1844         struct compat_ebt_replace repl, tmp;
1845         struct ebt_counter *oldcounters;
1846         struct ebt_table_info tinfo;
1847         int ret;
1848         void __user *pos;
1849
1850         memset(&tinfo, 0, sizeof(tinfo));
1851
1852         if (cmd == EBT_SO_GET_ENTRIES) {
1853                 tinfo.entries_size = t->private->entries_size;
1854                 tinfo.nentries = t->private->nentries;
1855                 tinfo.entries = t->private->entries;
1856                 oldcounters = t->private->counters;
1857         } else {
1858                 tinfo.entries_size = t->table->entries_size;
1859                 tinfo.nentries = t->table->nentries;
1860                 tinfo.entries = t->table->entries;
1861                 oldcounters = t->table->counters;
1862         }
1863
1864         if (copy_from_user(&tmp, user, sizeof(tmp)))
1865                 return -EFAULT;
1866
1867         if (tmp.nentries != tinfo.nentries ||
1868            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1869                 return -EINVAL;
1870
1871         memcpy(&repl, &tmp, sizeof(repl));
1872         if (cmd == EBT_SO_GET_ENTRIES)
1873                 ret = compat_table_info(t->private, &repl);
1874         else
1875                 ret = compat_table_info(&tinfo, &repl);
1876         if (ret)
1877                 return ret;
1878
1879         if (*len != sizeof(tmp) + repl.entries_size +
1880            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1881                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1882                                 *len, tinfo.entries_size, repl.entries_size);
1883                 return -EINVAL;
1884         }
1885
1886         /* userspace might not need the counters */
1887         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1888                                         tmp.num_counters, tinfo.nentries);
1889         if (ret)
1890                 return ret;
1891
1892         pos = compat_ptr(tmp.entries);
1893         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1894                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1895 }
1896
1897 struct ebt_entries_buf_state {
1898         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1899         u32 buf_kern_len;       /* total size of kernel buffer */
1900         u32 buf_kern_offset;    /* amount of data copied so far */
1901         u32 buf_user_offset;    /* read position in userspace buffer */
1902 };
1903
1904 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1905 {
1906         state->buf_kern_offset += sz;
1907         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1908 }
1909
1910 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1911                        void *data, unsigned int sz)
1912 {
1913         if (state->buf_kern_start == NULL)
1914                 goto count_only;
1915
1916         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1917                 return -EINVAL;
1918
1919         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1920
1921  count_only:
1922         state->buf_user_offset += sz;
1923         return ebt_buf_count(state, sz);
1924 }
1925
1926 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1927 {
1928         char *b = state->buf_kern_start;
1929
1930         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1931                 return -EINVAL;
1932
1933         if (b != NULL && sz > 0)
1934                 memset(b + state->buf_kern_offset, 0, sz);
1935         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1936         return ebt_buf_count(state, sz);
1937 }
1938
1939 enum compat_mwt {
1940         EBT_COMPAT_MATCH,
1941         EBT_COMPAT_WATCHER,
1942         EBT_COMPAT_TARGET,
1943 };
1944
1945 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1946                                 enum compat_mwt compat_mwt,
1947                                 struct ebt_entries_buf_state *state,
1948                                 const unsigned char *base)
1949 {
1950         char name[EBT_EXTENSION_MAXNAMELEN];
1951         struct xt_match *match;
1952         struct xt_target *wt;
1953         void *dst = NULL;
1954         int off, pad = 0;
1955         unsigned int size_kern, match_size = mwt->match_size;
1956
1957         strlcpy(name, mwt->u.name, sizeof(name));
1958
1959         if (state->buf_kern_start)
1960                 dst = state->buf_kern_start + state->buf_kern_offset;
1961
1962         switch (compat_mwt) {
1963         case EBT_COMPAT_MATCH:
1964                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1965                                               mwt->u.revision);
1966                 if (IS_ERR(match))
1967                         return PTR_ERR(match);
1968
1969                 off = ebt_compat_match_offset(match, match_size);
1970                 if (dst) {
1971                         if (match->compat_from_user)
1972                                 match->compat_from_user(dst, mwt->data);
1973                         else
1974                                 memcpy(dst, mwt->data, match_size);
1975                 }
1976
1977                 size_kern = match->matchsize;
1978                 if (unlikely(size_kern == -1))
1979                         size_kern = match_size;
1980                 module_put(match->me);
1981                 break;
1982         case EBT_COMPAT_WATCHER: /* fallthrough */
1983         case EBT_COMPAT_TARGET:
1984                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1985                                             mwt->u.revision);
1986                 if (IS_ERR(wt))
1987                         return PTR_ERR(wt);
1988                 off = xt_compat_target_offset(wt);
1989
1990                 if (dst) {
1991                         if (wt->compat_from_user)
1992                                 wt->compat_from_user(dst, mwt->data);
1993                         else
1994                                 memcpy(dst, mwt->data, match_size);
1995                 }
1996
1997                 size_kern = wt->targetsize;
1998                 module_put(wt->me);
1999                 break;
2000
2001         default:
2002                 return -EINVAL;
2003         }
2004
2005         state->buf_kern_offset += match_size + off;
2006         state->buf_user_offset += match_size;
2007         pad = XT_ALIGN(size_kern) - size_kern;
2008
2009         if (pad > 0 && dst) {
2010                 if (WARN_ON(state->buf_kern_len <= pad))
2011                         return -EINVAL;
2012                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2013                         return -EINVAL;
2014                 memset(dst + size_kern, 0, pad);
2015         }
2016         return off + match_size;
2017 }
2018
2019 /* return size of all matches, watchers or target, including necessary
2020  * alignment and padding.
2021  */
2022 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2023                         unsigned int size_left, enum compat_mwt type,
2024                         struct ebt_entries_buf_state *state, const void *base)
2025 {
2026         int growth = 0;
2027         char *buf;
2028
2029         if (size_left == 0)
2030                 return 0;
2031
2032         buf = (char *) match32;
2033
2034         while (size_left >= sizeof(*match32)) {
2035                 struct ebt_entry_match *match_kern;
2036                 int ret;
2037
2038                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2039                 if (match_kern) {
2040                         char *tmp;
2041                         tmp = state->buf_kern_start + state->buf_kern_offset;
2042                         match_kern = (struct ebt_entry_match *) tmp;
2043                 }
2044                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2045                 if (ret < 0)
2046                         return ret;
2047                 size_left -= sizeof(*match32);
2048
2049                 /* add padding before match->data (if any) */
2050                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2051                 if (ret < 0)
2052                         return ret;
2053
2054                 if (match32->match_size > size_left)
2055                         return -EINVAL;
2056
2057                 size_left -= match32->match_size;
2058
2059                 ret = compat_mtw_from_user(match32, type, state, base);
2060                 if (ret < 0)
2061                         return ret;
2062
2063                 if (WARN_ON(ret < match32->match_size))
2064                         return -EINVAL;
2065                 growth += ret - match32->match_size;
2066                 growth += ebt_compat_entry_padsize();
2067
2068                 buf += sizeof(*match32);
2069                 buf += match32->match_size;
2070
2071                 if (match_kern)
2072                         match_kern->match_size = ret;
2073
2074                 if (WARN_ON(type == EBT_COMPAT_TARGET && size_left))
2075                         return -EINVAL;
2076
2077                 match32 = (struct compat_ebt_entry_mwt *) buf;
2078         }
2079
2080         return growth;
2081 }
2082
2083 /* called for all ebt_entry structures. */
2084 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2085                           unsigned int *total,
2086                           struct ebt_entries_buf_state *state)
2087 {
2088         unsigned int i, j, startoff, new_offset = 0;
2089         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2090         unsigned int offsets[4];
2091         unsigned int *offsets_update = NULL;
2092         int ret;
2093         char *buf_start;
2094
2095         if (*total < sizeof(struct ebt_entries))
2096                 return -EINVAL;
2097
2098         if (!entry->bitmask) {
2099                 *total -= sizeof(struct ebt_entries);
2100                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2101         }
2102         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2103                 return -EINVAL;
2104
2105         startoff = state->buf_user_offset;
2106         /* pull in most part of ebt_entry, it does not need to be changed. */
2107         ret = ebt_buf_add(state, entry,
2108                         offsetof(struct ebt_entry, watchers_offset));
2109         if (ret < 0)
2110                 return ret;
2111
2112         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2113         memcpy(&offsets[1], &entry->watchers_offset,
2114                         sizeof(offsets) - sizeof(offsets[0]));
2115
2116         if (state->buf_kern_start) {
2117                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2118                 offsets_update = (unsigned int *) buf_start;
2119         }
2120         ret = ebt_buf_add(state, &offsets[1],
2121                         sizeof(offsets) - sizeof(offsets[0]));
2122         if (ret < 0)
2123                 return ret;
2124         buf_start = (char *) entry;
2125         /* 0: matches offset, always follows ebt_entry.
2126          * 1: watchers offset, from ebt_entry structure
2127          * 2: target offset, from ebt_entry structure
2128          * 3: next ebt_entry offset, from ebt_entry structure
2129          *
2130          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2131          */
2132         for (i = 0; i < 4 ; ++i) {
2133                 if (offsets[i] > *total)
2134                         return -EINVAL;
2135
2136                 if (i < 3 && offsets[i] == *total)
2137                         return -EINVAL;
2138
2139                 if (i == 0)
2140                         continue;
2141                 if (offsets[i-1] > offsets[i])
2142                         return -EINVAL;
2143         }
2144
2145         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2146                 struct compat_ebt_entry_mwt *match32;
2147                 unsigned int size;
2148                 char *buf = buf_start + offsets[i];
2149
2150                 if (offsets[i] > offsets[j])
2151                         return -EINVAL;
2152
2153                 match32 = (struct compat_ebt_entry_mwt *) buf;
2154                 size = offsets[j] - offsets[i];
2155                 ret = ebt_size_mwt(match32, size, i, state, base);
2156                 if (ret < 0)
2157                         return ret;
2158                 new_offset += ret;
2159                 if (offsets_update && new_offset) {
2160                         pr_debug("change offset %d to %d\n",
2161                                 offsets_update[i], offsets[j] + new_offset);
2162                         offsets_update[i] = offsets[j] + new_offset;
2163                 }
2164         }
2165
2166         if (state->buf_kern_start == NULL) {
2167                 unsigned int offset = buf_start - (char *) base;
2168
2169                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2170                 if (ret < 0)
2171                         return ret;
2172         }
2173
2174         startoff = state->buf_user_offset - startoff;
2175
2176         if (WARN_ON(*total < startoff))
2177                 return -EINVAL;
2178         *total -= startoff;
2179         return 0;
2180 }
2181
2182 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2183  * It might need more memory when copied to a 64 bit kernel in case
2184  * userspace is 32-bit. So, first task: find out how much memory is needed.
2185  *
2186  * Called before validation is performed.
2187  */
2188 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2189                                 struct ebt_entries_buf_state *state)
2190 {
2191         unsigned int size_remaining = size_user;
2192         int ret;
2193
2194         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2195                                         &size_remaining, state);
2196         if (ret < 0)
2197                 return ret;
2198
2199         WARN_ON(size_remaining);
2200         return state->buf_kern_offset;
2201 }
2202
2203
2204 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2205                                             void __user *user, unsigned int len)
2206 {
2207         struct compat_ebt_replace tmp;
2208         int i;
2209
2210         if (len < sizeof(tmp))
2211                 return -EINVAL;
2212
2213         if (copy_from_user(&tmp, user, sizeof(tmp)))
2214                 return -EFAULT;
2215
2216         if (len != sizeof(tmp) + tmp.entries_size)
2217                 return -EINVAL;
2218
2219         if (tmp.entries_size == 0)
2220                 return -EINVAL;
2221
2222         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2223                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2224                 return -ENOMEM;
2225         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2226                 return -ENOMEM;
2227
2228         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2229
2230         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2231         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2232                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2233
2234         repl->num_counters = tmp.num_counters;
2235         repl->counters = compat_ptr(tmp.counters);
2236         repl->entries = compat_ptr(tmp.entries);
2237         return 0;
2238 }
2239
2240 static int compat_do_replace(struct net *net, void __user *user,
2241                              unsigned int len)
2242 {
2243         int ret, i, countersize, size64;
2244         struct ebt_table_info *newinfo;
2245         struct ebt_replace tmp;
2246         struct ebt_entries_buf_state state;
2247         void *entries_tmp;
2248
2249         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2250         if (ret) {
2251                 /* try real handler in case userland supplied needed padding */
2252                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2253                         ret = 0;
2254                 return ret;
2255         }
2256
2257         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2258         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2259         if (!newinfo)
2260                 return -ENOMEM;
2261
2262         if (countersize)
2263                 memset(newinfo->counters, 0, countersize);
2264
2265         memset(&state, 0, sizeof(state));
2266
2267         newinfo->entries = vmalloc(tmp.entries_size);
2268         if (!newinfo->entries) {
2269                 ret = -ENOMEM;
2270                 goto free_newinfo;
2271         }
2272         if (copy_from_user(
2273            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2274                 ret = -EFAULT;
2275                 goto free_entries;
2276         }
2277
2278         entries_tmp = newinfo->entries;
2279
2280         xt_compat_lock(NFPROTO_BRIDGE);
2281
2282         ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2283         if (ret < 0)
2284                 goto out_unlock;
2285         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2286         if (ret < 0)
2287                 goto out_unlock;
2288
2289         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2290                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2291                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2292
2293         size64 = ret;
2294         newinfo->entries = vmalloc(size64);
2295         if (!newinfo->entries) {
2296                 vfree(entries_tmp);
2297                 ret = -ENOMEM;
2298                 goto out_unlock;
2299         }
2300
2301         memset(&state, 0, sizeof(state));
2302         state.buf_kern_start = newinfo->entries;
2303         state.buf_kern_len = size64;
2304
2305         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2306         if (WARN_ON(ret < 0))
2307                 goto out_unlock;
2308
2309         vfree(entries_tmp);
2310         tmp.entries_size = size64;
2311
2312         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2313                 char __user *usrptr;
2314                 if (tmp.hook_entry[i]) {
2315                         unsigned int delta;
2316                         usrptr = (char __user *) tmp.hook_entry[i];
2317                         delta = usrptr - tmp.entries;
2318                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2319                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2320                 }
2321         }
2322
2323         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2324         xt_compat_unlock(NFPROTO_BRIDGE);
2325
2326         ret = do_replace_finish(net, &tmp, newinfo);
2327         if (ret == 0)
2328                 return ret;
2329 free_entries:
2330         vfree(newinfo->entries);
2331 free_newinfo:
2332         vfree(newinfo);
2333         return ret;
2334 out_unlock:
2335         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2336         xt_compat_unlock(NFPROTO_BRIDGE);
2337         goto free_entries;
2338 }
2339
2340 static int compat_update_counters(struct net *net, void __user *user,
2341                                   unsigned int len)
2342 {
2343         struct compat_ebt_replace hlp;
2344
2345         if (copy_from_user(&hlp, user, sizeof(hlp)))
2346                 return -EFAULT;
2347
2348         /* try real handler in case userland supplied needed padding */
2349         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2350                 return update_counters(net, user, len);
2351
2352         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2353                                         hlp.num_counters, user, len);
2354 }
2355
2356 static int compat_do_ebt_set_ctl(struct sock *sk,
2357                 int cmd, void __user *user, unsigned int len)
2358 {
2359         int ret;
2360         struct net *net = sock_net(sk);
2361
2362         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2363                 return -EPERM;
2364
2365         switch (cmd) {
2366         case EBT_SO_SET_ENTRIES:
2367                 ret = compat_do_replace(net, user, len);
2368                 break;
2369         case EBT_SO_SET_COUNTERS:
2370                 ret = compat_update_counters(net, user, len);
2371                 break;
2372         default:
2373                 ret = -EINVAL;
2374         }
2375         return ret;
2376 }
2377
2378 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2379                 void __user *user, int *len)
2380 {
2381         int ret;
2382         struct compat_ebt_replace tmp;
2383         struct ebt_table *t;
2384         struct net *net = sock_net(sk);
2385
2386         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2387                 return -EPERM;
2388
2389         /* try real handler in case userland supplied needed padding */
2390         if ((cmd == EBT_SO_GET_INFO ||
2391              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2392                         return do_ebt_get_ctl(sk, cmd, user, len);
2393
2394         if (copy_from_user(&tmp, user, sizeof(tmp)))
2395                 return -EFAULT;
2396
2397         tmp.name[sizeof(tmp.name) - 1] = '\0';
2398
2399         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2400         if (!t)
2401                 return ret;
2402
2403         xt_compat_lock(NFPROTO_BRIDGE);
2404         switch (cmd) {
2405         case EBT_SO_GET_INFO:
2406                 tmp.nentries = t->private->nentries;
2407                 ret = compat_table_info(t->private, &tmp);
2408                 if (ret)
2409                         goto out;
2410                 tmp.valid_hooks = t->valid_hooks;
2411
2412                 if (copy_to_user(user, &tmp, *len) != 0) {
2413                         ret = -EFAULT;
2414                         break;
2415                 }
2416                 ret = 0;
2417                 break;
2418         case EBT_SO_GET_INIT_INFO:
2419                 tmp.nentries = t->table->nentries;
2420                 tmp.entries_size = t->table->entries_size;
2421                 tmp.valid_hooks = t->table->valid_hooks;
2422
2423                 if (copy_to_user(user, &tmp, *len) != 0) {
2424                         ret = -EFAULT;
2425                         break;
2426                 }
2427                 ret = 0;
2428                 break;
2429         case EBT_SO_GET_ENTRIES:
2430         case EBT_SO_GET_INIT_ENTRIES:
2431                 /* try real handler first in case of userland-side padding.
2432                  * in case we are dealing with an 'ordinary' 32 bit binary
2433                  * without 64bit compatibility padding, this will fail right
2434                  * after copy_from_user when the *len argument is validated.
2435                  *
2436                  * the compat_ variant needs to do one pass over the kernel
2437                  * data set to adjust for size differences before it the check.
2438                  */
2439                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2440                         ret = 0;
2441                 else
2442                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2443                 break;
2444         default:
2445                 ret = -EINVAL;
2446         }
2447  out:
2448         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2449         xt_compat_unlock(NFPROTO_BRIDGE);
2450         mutex_unlock(&ebt_mutex);
2451         return ret;
2452 }
2453 #endif
2454
2455 static struct nf_sockopt_ops ebt_sockopts = {
2456         .pf             = PF_INET,
2457         .set_optmin     = EBT_BASE_CTL,
2458         .set_optmax     = EBT_SO_SET_MAX + 1,
2459         .set            = do_ebt_set_ctl,
2460 #ifdef CONFIG_COMPAT
2461         .compat_set     = compat_do_ebt_set_ctl,
2462 #endif
2463         .get_optmin     = EBT_BASE_CTL,
2464         .get_optmax     = EBT_SO_GET_MAX + 1,
2465         .get            = do_ebt_get_ctl,
2466 #ifdef CONFIG_COMPAT
2467         .compat_get     = compat_do_ebt_get_ctl,
2468 #endif
2469         .owner          = THIS_MODULE,
2470 };
2471
2472 static int __init ebtables_init(void)
2473 {
2474         int ret;
2475
2476         ret = xt_register_target(&ebt_standard_target);
2477         if (ret < 0)
2478                 return ret;
2479         ret = nf_register_sockopt(&ebt_sockopts);
2480         if (ret < 0) {
2481                 xt_unregister_target(&ebt_standard_target);
2482                 return ret;
2483         }
2484
2485         return 0;
2486 }
2487
2488 static void __exit ebtables_fini(void)
2489 {
2490         nf_unregister_sockopt(&ebt_sockopts);
2491         xt_unregister_target(&ebt_standard_target);
2492 }
2493
2494 EXPORT_SYMBOL(ebt_register_table);
2495 EXPORT_SYMBOL(ebt_unregister_table);
2496 EXPORT_SYMBOL(ebt_do_table);
2497 module_init(ebtables_init);
2498 module_exit(ebtables_fini);
2499 MODULE_LICENSE("GPL");