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);
 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 static inline const struct ebt_entry_target *
 181 ebt_get_target_c(const struct ebt_entry *e)
 182 {
 183         return ebt_get_target((struct ebt_entry *)e);
 184 }
 185
 186 /* Do some firewalling */
 187 unsigned int ebt_do_table(struct sk_buff *skb,
 188                           const struct nf_hook_state *state,
 189                           struct ebt_table *table)
 190 {
 191         unsigned int hook = state->hook;
 192         int i, nentries;
 193         struct ebt_entry *point;
 194         struct ebt_counter *counter_base, *cb_base;
 195         const struct ebt_entry_target *t;
 196         int verdict, sp = 0;
 197         struct ebt_chainstack *cs;
 198         struct ebt_entries *chaininfo;
 199         const char *base;
 200         const struct ebt_table_info *private;
 201         struct xt_action_param acpar;
 202
 203         acpar.state   = state;
 204         acpar.hotdrop = false;
 205
 206         read_lock_bh(&table->lock);
 207         private = table->private;
 208         cb_base = COUNTER_BASE(private->counters, private->nentries,
 209            smp_processor_id());
 210         if (private->chainstack)
 211                 cs = private->chainstack[smp_processor_id()];
 212         else
 213                 cs = NULL;
 214         chaininfo = private->hook_entry[hook];
 215         nentries = private->hook_entry[hook]->nentries;
 216         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 217         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 218         /* base for chain jumps */
 219         base = private->entries;
 220         i = 0;
 221         while (i < nentries) {
 222                 if (ebt_basic_match(point, skb, state->in, state->out))
 223                         goto letscontinue;
 224
 225                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 226                         goto letscontinue;
 227                 if (acpar.hotdrop) {
 228                         read_unlock_bh(&table->lock);
 229                         return NF_DROP;
 230                 }
 231
 232                 ADD_COUNTER(*(counter_base + i), 1, skb->len);
 233
 234                 /* these should only watch: not modify, nor tell us
 235                  * what to do with the packet
 236                  */
 237                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 238
 239                 t = ebt_get_target_c(point);
 240                 /* standard target */
 241                 if (!t->u.target->target)
 242                         verdict = ((struct ebt_standard_target *)t)->verdict;
 243                 else {
 244                         acpar.target   = t->u.target;
 245                         acpar.targinfo = t->data;
 246                         verdict = t->u.target->target(skb, &acpar);
 247                 }
 248                 if (verdict == EBT_ACCEPT) {
 249                         read_unlock_bh(&table->lock);
 250                         return NF_ACCEPT;
 251                 }
 252                 if (verdict == EBT_DROP) {
 253                         read_unlock_bh(&table->lock);
 254                         return NF_DROP;
 255                 }
 256                 if (verdict == EBT_RETURN) {
 257 letsreturn:
 258                         if (WARN(sp == 0, "RETURN on base chain")) {
 259                                 /* act like this is EBT_CONTINUE */
 260                                 goto letscontinue;
 261                         }
 262
 263                         sp--;
 264                         /* put all the local variables right */
 265                         i = cs[sp].n;
 266                         chaininfo = cs[sp].chaininfo;
 267                         nentries = chaininfo->nentries;
 268                         point = cs[sp].e;
 269                         counter_base = cb_base +
 270                            chaininfo->counter_offset;
 271                         continue;
 272                 }
 273                 if (verdict == EBT_CONTINUE)
 274                         goto letscontinue;
 275
 276                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 277                         read_unlock_bh(&table->lock);
 278                         return NF_DROP;
 279                 }
 280
 281                 /* jump to a udc */
 282                 cs[sp].n = i + 1;
 283                 cs[sp].chaininfo = chaininfo;
 284                 cs[sp].e = ebt_next_entry(point);
 285                 i = 0;
 286                 chaininfo = (struct ebt_entries *) (base + verdict);
 287
 288                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 289                         read_unlock_bh(&table->lock);
 290                         return NF_DROP;
 291                 }
 292
 293                 nentries = chaininfo->nentries;
 294                 point = (struct ebt_entry *)chaininfo->data;
 295                 counter_base = cb_base + chaininfo->counter_offset;
 296                 sp++;
 297                 continue;
 298 letscontinue:
 299                 point = ebt_next_entry(point);
 300                 i++;
 301         }
 302
 303         /* I actually like this :) */
 304         if (chaininfo->policy == EBT_RETURN)
 305                 goto letsreturn;
 306         if (chaininfo->policy == EBT_ACCEPT) {
 307                 read_unlock_bh(&table->lock);
 308                 return NF_ACCEPT;
 309         }
 310         read_unlock_bh(&table->lock);
 311         return NF_DROP;
 312 }
 313
 314 /* If it succeeds, returns element and locks mutex */
 315 static inline void *
 316 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 317                         struct mutex *mutex)
 318 {
 319         struct {
 320                 struct list_head list;
 321                 char name[EBT_FUNCTION_MAXNAMELEN];
 322         } *e;
 323
 324         mutex_lock(mutex);
 325         list_for_each_entry(e, head, list) {
 326                 if (strcmp(e->name, name) == 0)
 327                         return e;
 328         }
 329         *error = -ENOENT;
 330         mutex_unlock(mutex);
 331         return NULL;
 332 }
 333
 334 static void *
 335 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 336                  int *error, struct mutex *mutex)
 337 {
 338         return try_then_request_module(
 339                         find_inlist_lock_noload(head, name, error, mutex),
 340                         "%s%s", prefix, name);
 341 }
 342
 343 static inline struct ebt_table *
 344 find_table_lock(struct net *net, const char *name, int *error,
 345                 struct mutex *mutex)
 346 {
 347         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 348                                 "ebtable_", error, mutex);
 349 }
 350
 351 static inline void ebt_free_table_info(struct ebt_table_info *info)
 352 {
 353         int i;
 354
 355         if (info->chainstack) {
 356                 for_each_possible_cpu(i)
 357                         vfree(info->chainstack[i]);
 358                 vfree(info->chainstack);
 359         }
 360 }
 361 static inline int
 362 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 363                 unsigned int *cnt)
 364 {
 365         const struct ebt_entry *e = par->entryinfo;
 366         struct xt_match *match;
 367         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 368         int ret;
 369
 370         if (left < sizeof(struct ebt_entry_match) ||
 371             left - sizeof(struct ebt_entry_match) < m->match_size)
 372                 return -EINVAL;
 373
 374         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 375         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 376                 if (!IS_ERR(match))
 377                         module_put(match->me);
 378                 request_module("ebt_%s", m->u.name);
 379                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 380         }
 381         if (IS_ERR(match))
 382                 return PTR_ERR(match);
 383         m->u.match = match;
 384
 385         par->match     = match;
 386         par->matchinfo = m->data;
 387         ret = xt_check_match(par, m->match_size,
 388               e->ethproto, e->invflags & EBT_IPROTO);
 389         if (ret < 0) {
 390                 module_put(match->me);
 391                 return ret;
 392         }
 393
 394         (*cnt)++;
 395         return 0;
 396 }
 397
 398 static inline int
 399 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 400                   unsigned int *cnt)
 401 {
 402         const struct ebt_entry *e = par->entryinfo;
 403         struct xt_target *watcher;
 404         size_t left = ((char *)e + e->target_offset) - (char *)w;
 405         int ret;
 406
 407         if (left < sizeof(struct ebt_entry_watcher) ||
 408            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 409                 return -EINVAL;
 410
 411         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 412         if (IS_ERR(watcher))
 413                 return PTR_ERR(watcher);
 414
 415         if (watcher->family != NFPROTO_BRIDGE) {
 416                 module_put(watcher->me);
 417                 return -ENOENT;
 418         }
 419
 420         w->u.watcher = watcher;
 421
 422         par->target   = watcher;
 423         par->targinfo = w->data;
 424         ret = xt_check_target(par, w->watcher_size,
 425               e->ethproto, e->invflags & EBT_IPROTO);
 426         if (ret < 0) {
 427                 module_put(watcher->me);
 428                 return ret;
 429         }
 430
 431         (*cnt)++;
 432         return 0;
 433 }
 434
 435 static int ebt_verify_pointers(const struct ebt_replace *repl,
 436                                struct ebt_table_info *newinfo)
 437 {
 438         unsigned int limit = repl->entries_size;
 439         unsigned int valid_hooks = repl->valid_hooks;
 440         unsigned int offset = 0;
 441         int i;
 442
 443         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 444                 newinfo->hook_entry[i] = NULL;
 445
 446         newinfo->entries_size = repl->entries_size;
 447         newinfo->nentries = repl->nentries;
 448
 449         while (offset < limit) {
 450                 size_t left = limit - offset;
 451                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 452
 453                 if (left < sizeof(unsigned int))
 454                         break;
 455
 456                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 457                         if ((valid_hooks & (1 << i)) == 0)
 458                                 continue;
 459                         if ((char __user *)repl->hook_entry[i] ==
 460                              repl->entries + offset)
 461                                 break;
 462                 }
 463
 464                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 465                         if (e->bitmask != 0) {
 466                                 /* we make userspace set this right,
 467                                  * so there is no misunderstanding
 468                                  */
 469                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 470                                          "in distinguisher\n");
 471                                 return -EINVAL;
 472                         }
 473                         if (i != NF_BR_NUMHOOKS)
 474                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 475                         if (left < sizeof(struct ebt_entries))
 476                                 break;
 477                         offset += sizeof(struct ebt_entries);
 478                 } else {
 479                         if (left < sizeof(struct ebt_entry))
 480                                 break;
 481                         if (left < e->next_offset)
 482                                 break;
 483                         if (e->next_offset < sizeof(struct ebt_entry))
 484                                 return -EINVAL;
 485                         offset += e->next_offset;
 486                 }
 487         }
 488         if (offset != limit) {
 489                 BUGPRINT("entries_size too small\n");
 490                 return -EINVAL;
 491         }
 492
 493         /* check if all valid hooks have a chain */
 494         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 495                 if (!newinfo->hook_entry[i] &&
 496                    (valid_hooks & (1 << i))) {
 497                         BUGPRINT("Valid hook without chain\n");
 498                         return -EINVAL;
 499                 }
 500         }
 501         return 0;
 502 }
 503
 504 /* this one is very careful, as it is the first function
 505  * to parse the userspace data
 506  */
 507 static inline int
 508 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 509                                const struct ebt_table_info *newinfo,
 510                                unsigned int *n, unsigned int *cnt,
 511                                unsigned int *totalcnt, unsigned int *udc_cnt)
 512 {
 513         int i;
 514
 515         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 516                 if ((void *)e == (void *)newinfo->hook_entry[i])
 517                         break;
 518         }
 519         /* beginning of a new chain
 520          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 521          */
 522         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 523                 /* this checks if the previous chain has as many entries
 524                  * as it said it has
 525                  */
 526                 if (*n != *cnt) {
 527                         BUGPRINT("nentries does not equal the nr of entries "
 528                                  "in the chain\n");
 529                         return -EINVAL;
 530                 }
 531                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 532                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 533                         /* only RETURN from udc */
 534                         if (i != NF_BR_NUMHOOKS ||
 535                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 536                                 BUGPRINT("bad policy\n");
 537                                 return -EINVAL;
 538                         }
 539                 }
 540                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 541                         (*udc_cnt)++;
 542                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 543                         BUGPRINT("counter_offset != totalcnt");
 544                         return -EINVAL;
 545                 }
 546                 *n = ((struct ebt_entries *)e)->nentries;
 547                 *cnt = 0;
 548                 return 0;
 549         }
 550         /* a plain old entry, heh */
 551         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 552            e->watchers_offset > e->target_offset ||
 553            e->target_offset >= e->next_offset) {
 554                 BUGPRINT("entry offsets not in right order\n");
 555                 return -EINVAL;
 556         }
 557         /* this is not checked anywhere else */
 558         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 559                 BUGPRINT("target size too small\n");
 560                 return -EINVAL;
 561         }
 562         (*cnt)++;
 563         (*totalcnt)++;
 564         return 0;
 565 }
 566
 567 struct ebt_cl_stack {
 568         struct ebt_chainstack cs;
 569         int from;
 570         unsigned int hookmask;
 571 };
 572
 573 /* We need these positions to check that the jumps to a different part of the
 574  * entries is a jump to the beginning of a new chain.
 575  */
 576 static inline int
 577 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 578                       unsigned int *n, struct ebt_cl_stack *udc)
 579 {
 580         int i;
 581
 582         /* we're only interested in chain starts */
 583         if (e->bitmask)
 584                 return 0;
 585         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 586                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 587                         break;
 588         }
 589         /* only care about udc */
 590         if (i != NF_BR_NUMHOOKS)
 591                 return 0;
 592
 593         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 594         /* these initialisations are depended on later in check_chainloops() */
 595         udc[*n].cs.n = 0;
 596         udc[*n].hookmask = 0;
 597
 598         (*n)++;
 599         return 0;
 600 }
 601
 602 static inline int
 603 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 604 {
 605         struct xt_mtdtor_param par;
 606
 607         if (i && (*i)-- == 0)
 608                 return 1;
 609
 610         par.net       = net;
 611         par.match     = m->u.match;
 612         par.matchinfo = m->data;
 613         par.family    = NFPROTO_BRIDGE;
 614         if (par.match->destroy != NULL)
 615                 par.match->destroy(&par);
 616         module_put(par.match->me);
 617         return 0;
 618 }
 619
 620 static inline int
 621 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 622 {
 623         struct xt_tgdtor_param par;
 624
 625         if (i && (*i)-- == 0)
 626                 return 1;
 627
 628         par.net      = net;
 629         par.target   = w->u.watcher;
 630         par.targinfo = w->data;
 631         par.family   = NFPROTO_BRIDGE;
 632         if (par.target->destroy != NULL)
 633                 par.target->destroy(&par);
 634         module_put(par.target->me);
 635         return 0;
 636 }
 637
 638 static inline int
 639 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 640 {
 641         struct xt_tgdtor_param par;
 642         struct ebt_entry_target *t;
 643
 644         if (e->bitmask == 0)
 645                 return 0;
 646         /* we're done */
 647         if (cnt && (*cnt)-- == 0)
 648                 return 1;
 649         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 650         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 651         t = ebt_get_target(e);
 652
 653         par.net      = net;
 654         par.target   = t->u.target;
 655         par.targinfo = t->data;
 656         par.family   = NFPROTO_BRIDGE;
 657         if (par.target->destroy != NULL)
 658                 par.target->destroy(&par);
 659         module_put(par.target->me);
 660         return 0;
 661 }
 662
 663 static inline int
 664 ebt_check_entry(struct ebt_entry *e, struct net *net,
 665                 const struct ebt_table_info *newinfo,
 666                 const char *name, unsigned int *cnt,
 667                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 668 {
 669         struct ebt_entry_target *t;
 670         struct xt_target *target;
 671         unsigned int i, j, hook = 0, hookmask = 0;
 672         size_t gap;
 673         int ret;
 674         struct xt_mtchk_param mtpar;
 675         struct xt_tgchk_param tgpar;
 676
 677         /* don't mess with the struct ebt_entries */
 678         if (e->bitmask == 0)
 679                 return 0;
 680
 681         if (e->bitmask & ~EBT_F_MASK) {
 682                 BUGPRINT("Unknown flag for bitmask\n");
 683                 return -EINVAL;
 684         }
 685         if (e->invflags & ~EBT_INV_MASK) {
 686                 BUGPRINT("Unknown flag for inv bitmask\n");
 687                 return -EINVAL;
 688         }
 689         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 690                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 691                 return -EINVAL;
 692         }
 693         /* what hook do we belong to? */
 694         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 695                 if (!newinfo->hook_entry[i])
 696                         continue;
 697                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 698                         hook = i;
 699                 else
 700                         break;
 701         }
 702         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 703          * a base chain
 704          */
 705         if (i < NF_BR_NUMHOOKS)
 706                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 707         else {
 708                 for (i = 0; i < udc_cnt; i++)
 709                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 710                                 break;
 711                 if (i == 0)
 712                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 713                 else
 714                         hookmask = cl_s[i - 1].hookmask;
 715         }
 716         i = 0;
 717
 718         memset(&mtpar, 0, sizeof(mtpar));
 719         memset(&tgpar, 0, sizeof(tgpar));
 720         mtpar.net       = tgpar.net       = net;
 721         mtpar.table     = tgpar.table     = name;
 722         mtpar.entryinfo = tgpar.entryinfo = e;
 723         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 724         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 725         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 726         if (ret != 0)
 727                 goto cleanup_matches;
 728         j = 0;
 729         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 730         if (ret != 0)
 731                 goto cleanup_watchers;
 732         t = ebt_get_target(e);
 733         gap = e->next_offset - e->target_offset;
 734
 735         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 736         if (IS_ERR(target)) {
 737                 ret = PTR_ERR(target);
 738                 goto cleanup_watchers;
 739         }
 740
 741         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 742         if (target->family != NFPROTO_BRIDGE) {
 743                 module_put(target->me);
 744                 ret = -ENOENT;
 745                 goto cleanup_watchers;
 746         }
 747
 748         t->u.target = target;
 749         if (t->u.target == &ebt_standard_target) {
 750                 if (gap < sizeof(struct ebt_standard_target)) {
 751                         BUGPRINT("Standard target size too big\n");
 752                         ret = -EFAULT;
 753                         goto cleanup_watchers;
 754                 }
 755                 if (((struct ebt_standard_target *)t)->verdict <
 756                    -NUM_STANDARD_TARGETS) {
 757                         BUGPRINT("Invalid standard target\n");
 758                         ret = -EFAULT;
 759                         goto cleanup_watchers;
 760                 }
 761         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 762                 module_put(t->u.target->me);
 763                 ret = -EFAULT;
 764                 goto cleanup_watchers;
 765         }
 766
 767         tgpar.target   = target;
 768         tgpar.targinfo = t->data;
 769         ret = xt_check_target(&tgpar, t->target_size,
 770               e->ethproto, e->invflags & EBT_IPROTO);
 771         if (ret < 0) {
 772                 module_put(target->me);
 773                 goto cleanup_watchers;
 774         }
 775         (*cnt)++;
 776         return 0;
 777 cleanup_watchers:
 778         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 779 cleanup_matches:
 780         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 781         return ret;
 782 }
 783
 784 /* checks for loops and sets the hook mask for udc
 785  * the hook mask for udc tells us from which base chains the udc can be
 786  * accessed. This mask is a parameter to the check() functions of the extensions
 787  */
 788 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 789                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 790 {
 791         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 792         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 793         const struct ebt_entry_target *t;
 794
 795         while (pos < nentries || chain_nr != -1) {
 796                 /* end of udc, go back one 'recursion' step */
 797                 if (pos == nentries) {
 798                         /* put back values of the time when this chain was called */
 799                         e = cl_s[chain_nr].cs.e;
 800                         if (cl_s[chain_nr].from != -1)
 801                                 nentries =
 802                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 803                         else
 804                                 nentries = chain->nentries;
 805                         pos = cl_s[chain_nr].cs.n;
 806                         /* make sure we won't see a loop that isn't one */
 807                         cl_s[chain_nr].cs.n = 0;
 808                         chain_nr = cl_s[chain_nr].from;
 809                         if (pos == nentries)
 810                                 continue;
 811                 }
 812                 t = ebt_get_target_c(e);
 813                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 814                         goto letscontinue;
 815                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 816                    e->next_offset) {
 817                         BUGPRINT("Standard target size too big\n");
 818                         return -1;
 819                 }
 820                 verdict = ((struct ebt_standard_target *)t)->verdict;
 821                 if (verdict >= 0) { /* jump to another chain */
 822                         struct ebt_entries *hlp2 =
 823                            (struct ebt_entries *)(base + verdict);
 824                         for (i = 0; i < udc_cnt; i++)
 825                                 if (hlp2 == cl_s[i].cs.chaininfo)
 826                                         break;
 827                         /* bad destination or loop */
 828                         if (i == udc_cnt) {
 829                                 BUGPRINT("bad destination\n");
 830                                 return -1;
 831                         }
 832                         if (cl_s[i].cs.n) {
 833                                 BUGPRINT("loop\n");
 834                                 return -1;
 835                         }
 836                         if (cl_s[i].hookmask & (1 << hooknr))
 837                                 goto letscontinue;
 838                         /* this can't be 0, so the loop test is correct */
 839                         cl_s[i].cs.n = pos + 1;
 840                         pos = 0;
 841                         cl_s[i].cs.e = ebt_next_entry(e);
 842                         e = (struct ebt_entry *)(hlp2->data);
 843                         nentries = hlp2->nentries;
 844                         cl_s[i].from = chain_nr;
 845                         chain_nr = i;
 846                         /* this udc is accessible from the base chain for hooknr */
 847                         cl_s[i].hookmask |= (1 << hooknr);
 848                         continue;
 849                 }
 850 letscontinue:
 851                 e = ebt_next_entry(e);
 852                 pos++;
 853         }
 854         return 0;
 855 }
 856
 857 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 858 static int translate_table(struct net *net, const char *name,
 859                            struct ebt_table_info *newinfo)
 860 {
 861         unsigned int i, j, k, udc_cnt;
 862         int ret;
 863         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 864
 865         i = 0;
 866         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 867                 i++;
 868         if (i == NF_BR_NUMHOOKS) {
 869                 BUGPRINT("No valid hooks specified\n");
 870                 return -EINVAL;
 871         }
 872         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 873                 BUGPRINT("Chains don't start at beginning\n");
 874                 return -EINVAL;
 875         }
 876         /* make sure chains are ordered after each other in same order
 877          * as their corresponding hooks
 878          */
 879         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 880                 if (!newinfo->hook_entry[j])
 881                         continue;
 882                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 883                         BUGPRINT("Hook order must be followed\n");
 884                         return -EINVAL;
 885                 }
 886                 i = j;
 887         }
 888
 889         /* do some early checkings and initialize some things */
 890         i = 0; /* holds the expected nr. of entries for the chain */
 891         j = 0; /* holds the up to now counted entries for the chain */
 892         k = 0; /* holds the total nr. of entries, should equal
 893                 * newinfo->nentries afterwards
 894                 */
 895         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 896         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 897            ebt_check_entry_size_and_hooks, newinfo,
 898            &i, &j, &k, &udc_cnt);
 899
 900         if (ret != 0)
 901                 return ret;
 902
 903         if (i != j) {
 904                 BUGPRINT("nentries does not equal the nr of entries in the "
 905                          "(last) chain\n");
 906                 return -EINVAL;
 907         }
 908         if (k != newinfo->nentries) {
 909                 BUGPRINT("Total nentries is wrong\n");
 910                 return -EINVAL;
 911         }
 912
 913         /* get the location of the udc, put them in an array
 914          * while we're at it, allocate the chainstack
 915          */
 916         if (udc_cnt) {
 917                 /* this will get free'd in do_replace()/ebt_register_table()
 918                  * if an error occurs
 919                  */
 920                 newinfo->chainstack =
 921                         vmalloc(array_size(nr_cpu_ids,
 922                                            sizeof(*(newinfo->chainstack))));
 923                 if (!newinfo->chainstack)
 924                         return -ENOMEM;
 925                 for_each_possible_cpu(i) {
 926                         newinfo->chainstack[i] =
 927                           vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 928                         if (!newinfo->chainstack[i]) {
 929                                 while (i)
 930                                         vfree(newinfo->chainstack[--i]);
 931                                 vfree(newinfo->chainstack);
 932                                 newinfo->chainstack = NULL;
 933                                 return -ENOMEM;
 934                         }
 935                 }
 936
 937                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 938                 if (!cl_s)
 939                         return -ENOMEM;
 940                 i = 0; /* the i'th udc */
 941                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 942                    ebt_get_udc_positions, newinfo, &i, cl_s);
 943                 /* sanity check */
 944                 if (i != udc_cnt) {
 945                         BUGPRINT("i != udc_cnt\n");
 946                         vfree(cl_s);
 947                         return -EFAULT;
 948                 }
 949         }
 950
 951         /* Check for loops */
 952         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 953                 if (newinfo->hook_entry[i])
 954                         if (check_chainloops(newinfo->hook_entry[i],
 955                            cl_s, udc_cnt, i, newinfo->entries)) {
 956                                 vfree(cl_s);
 957                                 return -EINVAL;
 958                         }
 959
 960         /* we now know the following (along with E=mc²):
 961          *  - the nr of entries in each chain is right
 962          *  - the size of the allocated space is right
 963          *  - all valid hooks have a corresponding chain
 964          *  - there are no loops
 965          *  - wrong data can still be on the level of a single entry
 966          *  - could be there are jumps to places that are not the
 967          *    beginning of a chain. This can only occur in chains that
 968          *    are not accessible from any base chains, so we don't care.
 969          */
 970
 971         /* used to know what we need to clean up if something goes wrong */
 972         i = 0;
 973         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 974            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 975         if (ret != 0) {
 976                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 977                                   ebt_cleanup_entry, net, &i);
 978         }
 979         vfree(cl_s);
 980         return ret;
 981 }
 982
 983 /* called under write_lock */
 984 static void get_counters(const struct ebt_counter *oldcounters,
 985                          struct ebt_counter *counters, unsigned int nentries)
 986 {
 987         int i, cpu;
 988         struct ebt_counter *counter_base;
 989
 990         /* counters of cpu 0 */
 991         memcpy(counters, oldcounters,
 992                sizeof(struct ebt_counter) * nentries);
 993
 994         /* add other counters to those of cpu 0 */
 995         for_each_possible_cpu(cpu) {
 996                 if (cpu == 0)
 997                         continue;
 998                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 999                 for (i = 0; i < nentries; i++)
1000                         ADD_COUNTER(counters[i], counter_base[i].pcnt,
1001                                     counter_base[i].bcnt);
1002         }
1003 }
1004
1005 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1006                               struct ebt_table_info *newinfo)
1007 {
1008         int ret;
1009         struct ebt_counter *counterstmp = NULL;
1010         /* used to be able to unlock earlier */
1011         struct ebt_table_info *table;
1012         struct ebt_table *t;
1013
1014         /* the user wants counters back
1015          * the check on the size is done later, when we have the lock
1016          */
1017         if (repl->num_counters) {
1018                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1019                 counterstmp = vmalloc(size);
1020                 if (!counterstmp)
1021                         return -ENOMEM;
1022         }
1023
1024         newinfo->chainstack = NULL;
1025         ret = ebt_verify_pointers(repl, newinfo);
1026         if (ret != 0)
1027                 goto free_counterstmp;
1028
1029         ret = translate_table(net, repl->name, newinfo);
1030
1031         if (ret != 0)
1032                 goto free_counterstmp;
1033
1034         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1035         if (!t) {
1036                 ret = -ENOENT;
1037                 goto free_iterate;
1038         }
1039
1040         /* the table doesn't like it */
1041         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1042                 goto free_unlock;
1043
1044         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1045                 BUGPRINT("Wrong nr. of counters requested\n");
1046                 ret = -EINVAL;
1047                 goto free_unlock;
1048         }
1049
1050         /* we have the mutex lock, so no danger in reading this pointer */
1051         table = t->private;
1052         /* make sure the table can only be rmmod'ed if it contains no rules */
1053         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1054                 ret = -ENOENT;
1055                 goto free_unlock;
1056         } else if (table->nentries && !newinfo->nentries)
1057                 module_put(t->me);
1058         /* we need an atomic snapshot of the counters */
1059         write_lock_bh(&t->lock);
1060         if (repl->num_counters)
1061                 get_counters(t->private->counters, counterstmp,
1062                    t->private->nentries);
1063
1064         t->private = newinfo;
1065         write_unlock_bh(&t->lock);
1066         mutex_unlock(&ebt_mutex);
1067         /* so, a user can change the chains while having messed up her counter
1068          * allocation. Only reason why this is done is because this way the lock
1069          * is held only once, while this doesn't bring the kernel into a
1070          * dangerous state.
1071          */
1072         if (repl->num_counters &&
1073            copy_to_user(repl->counters, counterstmp,
1074            repl->num_counters * sizeof(struct ebt_counter))) {
1075                 /* Silent error, can't fail, new table is already in place */
1076                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1077         }
1078
1079         /* decrease module count and free resources */
1080         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1081                           ebt_cleanup_entry, net, NULL);
1082
1083         vfree(table->entries);
1084         ebt_free_table_info(table);
1085         vfree(table);
1086         vfree(counterstmp);
1087
1088 #ifdef CONFIG_AUDIT
1089         if (audit_enabled) {
1090                 audit_log(audit_context(), GFP_KERNEL,
1091                           AUDIT_NETFILTER_CFG,
1092                           "table=%s family=%u entries=%u",
1093                           repl->name, AF_BRIDGE, repl->nentries);
1094         }
1095 #endif
1096         return ret;
1097
1098 free_unlock:
1099         mutex_unlock(&ebt_mutex);
1100 free_iterate:
1101         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1102                           ebt_cleanup_entry, net, NULL);
1103 free_counterstmp:
1104         vfree(counterstmp);
1105         /* can be initialized in translate_table() */
1106         ebt_free_table_info(newinfo);
1107         return ret;
1108 }
1109
1110 /* replace the table */
1111 static int do_replace(struct net *net, const void __user *user,
1112                       unsigned int len)
1113 {
1114         int ret, countersize;
1115         struct ebt_table_info *newinfo;
1116         struct ebt_replace tmp;
1117
1118         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1119                 return -EFAULT;
1120
1121         if (len != sizeof(tmp) + tmp.entries_size) {
1122                 BUGPRINT("Wrong len argument\n");
1123                 return -EINVAL;
1124         }
1125
1126         if (tmp.entries_size == 0) {
1127                 BUGPRINT("Entries_size never zero\n");
1128                 return -EINVAL;
1129         }
1130         /* overflow check */
1131         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1132                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1133                 return -ENOMEM;
1134         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1135                 return -ENOMEM;
1136
1137         tmp.name[sizeof(tmp.name) - 1] = 0;
1138
1139         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1140         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT,
1141                             PAGE_KERNEL);
1142         if (!newinfo)
1143                 return -ENOMEM;
1144
1145         if (countersize)
1146                 memset(newinfo->counters, 0, countersize);
1147
1148         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT,
1149                                      PAGE_KERNEL);
1150         if (!newinfo->entries) {
1151                 ret = -ENOMEM;
1152                 goto free_newinfo;
1153         }
1154         if (copy_from_user(
1155            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1156                 BUGPRINT("Couldn't copy entries from userspace\n");
1157                 ret = -EFAULT;
1158                 goto free_entries;
1159         }
1160
1161         ret = do_replace_finish(net, &tmp, newinfo);
1162         if (ret == 0)
1163                 return ret;
1164 free_entries:
1165         vfree(newinfo->entries);
1166 free_newinfo:
1167         vfree(newinfo);
1168         return ret;
1169 }
1170
1171 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1172 {
1173         mutex_lock(&ebt_mutex);
1174         list_del(&table->list);
1175         mutex_unlock(&ebt_mutex);
1176         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1177                           ebt_cleanup_entry, net, NULL);
1178         if (table->private->nentries)
1179                 module_put(table->me);
1180         vfree(table->private->entries);
1181         ebt_free_table_info(table->private);
1182         vfree(table->private);
1183         kfree(table);
1184 }
1185
1186 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1187                        const struct nf_hook_ops *ops, struct ebt_table **res)
1188 {
1189         struct ebt_table_info *newinfo;
1190         struct ebt_table *t, *table;
1191         struct ebt_replace_kernel *repl;
1192         int ret, i, countersize;
1193         void *p;
1194
1195         if (input_table == NULL || (repl = input_table->table) == NULL ||
1196             repl->entries == NULL || repl->entries_size == 0 ||
1197             repl->counters != NULL || input_table->private != NULL) {
1198                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1199                 return -EINVAL;
1200         }
1201
1202         /* Don't add one table to multiple lists. */
1203         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1204         if (!table) {
1205                 ret = -ENOMEM;
1206                 goto out;
1207         }
1208
1209         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1210         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1211         ret = -ENOMEM;
1212         if (!newinfo)
1213                 goto free_table;
1214
1215         p = vmalloc(repl->entries_size);
1216         if (!p)
1217                 goto free_newinfo;
1218
1219         memcpy(p, repl->entries, repl->entries_size);
1220         newinfo->entries = p;
1221
1222         newinfo->entries_size = repl->entries_size;
1223         newinfo->nentries = repl->nentries;
1224
1225         if (countersize)
1226                 memset(newinfo->counters, 0, countersize);
1227
1228         /* fill in newinfo and parse the entries */
1229         newinfo->chainstack = NULL;
1230         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1231                 if ((repl->valid_hooks & (1 << i)) == 0)
1232                         newinfo->hook_entry[i] = NULL;
1233                 else
1234                         newinfo->hook_entry[i] = p +
1235                                 ((char *)repl->hook_entry[i] - repl->entries);
1236         }
1237         ret = translate_table(net, repl->name, newinfo);
1238         if (ret != 0) {
1239                 BUGPRINT("Translate_table failed\n");
1240                 goto free_chainstack;
1241         }
1242
1243         if (table->check && table->check(newinfo, table->valid_hooks)) {
1244                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1245                 ret = -EINVAL;
1246                 goto free_chainstack;
1247         }
1248
1249         table->private = newinfo;
1250         rwlock_init(&table->lock);
1251         mutex_lock(&ebt_mutex);
1252         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1253                 if (strcmp(t->name, table->name) == 0) {
1254                         ret = -EEXIST;
1255                         BUGPRINT("Table name already exists\n");
1256                         goto free_unlock;
1257                 }
1258         }
1259
1260         /* Hold a reference count if the chains aren't empty */
1261         if (newinfo->nentries && !try_module_get(table->me)) {
1262                 ret = -ENOENT;
1263                 goto free_unlock;
1264         }
1265         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1266         mutex_unlock(&ebt_mutex);
1267
1268         WRITE_ONCE(*res, table);
1269
1270         if (!ops)
1271                 return 0;
1272
1273         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1274         if (ret) {
1275                 __ebt_unregister_table(net, table);
1276                 *res = NULL;
1277         }
1278
1279         return ret;
1280 free_unlock:
1281         mutex_unlock(&ebt_mutex);
1282 free_chainstack:
1283         ebt_free_table_info(newinfo);
1284         vfree(newinfo->entries);
1285 free_newinfo:
1286         vfree(newinfo);
1287 free_table:
1288         kfree(table);
1289 out:
1290         return ret;
1291 }
1292
1293 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1294                           const struct nf_hook_ops *ops)
1295 {
1296         if (ops)
1297                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1298         __ebt_unregister_table(net, table);
1299 }
1300
1301 /* userspace just supplied us with counters */
1302 static int do_update_counters(struct net *net, const char *name,
1303                                 struct ebt_counter __user *counters,
1304                                 unsigned int num_counters,
1305                                 const void __user *user, unsigned int len)
1306 {
1307         int i, ret;
1308         struct ebt_counter *tmp;
1309         struct ebt_table *t;
1310
1311         if (num_counters == 0)
1312                 return -EINVAL;
1313
1314         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1315         if (!tmp)
1316                 return -ENOMEM;
1317
1318         t = find_table_lock(net, name, &ret, &ebt_mutex);
1319         if (!t)
1320                 goto free_tmp;
1321
1322         if (num_counters != t->private->nentries) {
1323                 BUGPRINT("Wrong nr of counters\n");
1324                 ret = -EINVAL;
1325                 goto unlock_mutex;
1326         }
1327
1328         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1329                 ret = -EFAULT;
1330                 goto unlock_mutex;
1331         }
1332
1333         /* we want an atomic add of the counters */
1334         write_lock_bh(&t->lock);
1335
1336         /* we add to the counters of the first cpu */
1337         for (i = 0; i < num_counters; i++)
1338                 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt);
1339
1340         write_unlock_bh(&t->lock);
1341         ret = 0;
1342 unlock_mutex:
1343         mutex_unlock(&ebt_mutex);
1344 free_tmp:
1345         vfree(tmp);
1346         return ret;
1347 }
1348
1349 static int update_counters(struct net *net, const void __user *user,
1350                             unsigned int len)
1351 {
1352         struct ebt_replace hlp;
1353
1354         if (copy_from_user(&hlp, user, sizeof(hlp)))
1355                 return -EFAULT;
1356
1357         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1358                 return -EINVAL;
1359
1360         return do_update_counters(net, hlp.name, hlp.counters,
1361                                 hlp.num_counters, user, len);
1362 }
1363
1364 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1365                                   const char *data, int entrysize,
1366                                   int usersize, int datasize, u8 revision)
1367 {
1368         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1369
1370         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1371          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1372          */
1373         strlcpy(name, _name, sizeof(name));
1374         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1375             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1376             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1377             xt_data_to_user(um + entrysize, data, usersize, datasize,
1378                             XT_ALIGN(datasize)))
1379                 return -EFAULT;
1380
1381         return 0;
1382 }
1383
1384 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1385                                     const char *base, char __user *ubase)
1386 {
1387         return ebt_obj_to_user(ubase + ((char *)m - base),
1388                                m->u.match->name, m->data, sizeof(*m),
1389                                m->u.match->usersize, m->match_size,
1390                                m->u.match->revision);
1391 }
1392
1393 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1394                                       const char *base, char __user *ubase)
1395 {
1396         return ebt_obj_to_user(ubase + ((char *)w - base),
1397                                w->u.watcher->name, w->data, sizeof(*w),
1398                                w->u.watcher->usersize, w->watcher_size,
1399                                w->u.watcher->revision);
1400 }
1401
1402 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1403                                     char __user *ubase)
1404 {
1405         int ret;
1406         char __user *hlp;
1407         const struct ebt_entry_target *t;
1408
1409         if (e->bitmask == 0) {
1410                 /* special case !EBT_ENTRY_OR_ENTRIES */
1411                 if (copy_to_user(ubase + ((char *)e - base), e,
1412                                  sizeof(struct ebt_entries)))
1413                         return -EFAULT;
1414                 return 0;
1415         }
1416
1417         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1418                 return -EFAULT;
1419
1420         hlp = ubase + (((char *)e + e->target_offset) - base);
1421         t = ebt_get_target_c(e);
1422
1423         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1424         if (ret != 0)
1425                 return ret;
1426         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1427         if (ret != 0)
1428                 return ret;
1429         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1430                               t->u.target->usersize, t->target_size,
1431                               t->u.target->revision);
1432         if (ret != 0)
1433                 return ret;
1434
1435         return 0;
1436 }
1437
1438 static int copy_counters_to_user(struct ebt_table *t,
1439                                  const struct ebt_counter *oldcounters,
1440                                  void __user *user, unsigned int num_counters,
1441                                  unsigned int nentries)
1442 {
1443         struct ebt_counter *counterstmp;
1444         int ret = 0;
1445
1446         /* userspace might not need the counters */
1447         if (num_counters == 0)
1448                 return 0;
1449
1450         if (num_counters != nentries) {
1451                 BUGPRINT("Num_counters wrong\n");
1452                 return -EINVAL;
1453         }
1454
1455         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1456         if (!counterstmp)
1457                 return -ENOMEM;
1458
1459         write_lock_bh(&t->lock);
1460         get_counters(oldcounters, counterstmp, nentries);
1461         write_unlock_bh(&t->lock);
1462
1463         if (copy_to_user(user, counterstmp,
1464            nentries * sizeof(struct ebt_counter)))
1465                 ret = -EFAULT;
1466         vfree(counterstmp);
1467         return ret;
1468 }
1469
1470 /* called with ebt_mutex locked */
1471 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1472                                    const int *len, int cmd)
1473 {
1474         struct ebt_replace tmp;
1475         const struct ebt_counter *oldcounters;
1476         unsigned int entries_size, nentries;
1477         int ret;
1478         char *entries;
1479
1480         if (cmd == EBT_SO_GET_ENTRIES) {
1481                 entries_size = t->private->entries_size;
1482                 nentries = t->private->nentries;
1483                 entries = t->private->entries;
1484                 oldcounters = t->private->counters;
1485         } else {
1486                 entries_size = t->table->entries_size;
1487                 nentries = t->table->nentries;
1488                 entries = t->table->entries;
1489                 oldcounters = t->table->counters;
1490         }
1491
1492         if (copy_from_user(&tmp, user, sizeof(tmp)))
1493                 return -EFAULT;
1494
1495         if (*len != sizeof(struct ebt_replace) + entries_size +
1496            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1497                 return -EINVAL;
1498
1499         if (tmp.nentries != nentries) {
1500                 BUGPRINT("Nentries wrong\n");
1501                 return -EINVAL;
1502         }
1503
1504         if (tmp.entries_size != entries_size) {
1505                 BUGPRINT("Wrong size\n");
1506                 return -EINVAL;
1507         }
1508
1509         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1510                                         tmp.num_counters, nentries);
1511         if (ret)
1512                 return ret;
1513
1514         /* set the match/watcher/target names right */
1515         return EBT_ENTRY_ITERATE(entries, entries_size,
1516            ebt_entry_to_user, entries, tmp.entries);
1517 }
1518
1519 static int do_ebt_set_ctl(struct sock *sk,
1520         int cmd, void __user *user, unsigned int len)
1521 {
1522         int ret;
1523         struct net *net = sock_net(sk);
1524
1525         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1526                 return -EPERM;
1527
1528         switch (cmd) {
1529         case EBT_SO_SET_ENTRIES:
1530                 ret = do_replace(net, user, len);
1531                 break;
1532         case EBT_SO_SET_COUNTERS:
1533                 ret = update_counters(net, user, len);
1534                 break;
1535         default:
1536                 ret = -EINVAL;
1537         }
1538         return ret;
1539 }
1540
1541 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1542 {
1543         int ret;
1544         struct ebt_replace tmp;
1545         struct ebt_table *t;
1546         struct net *net = sock_net(sk);
1547
1548         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1549                 return -EPERM;
1550
1551         if (copy_from_user(&tmp, user, sizeof(tmp)))
1552                 return -EFAULT;
1553
1554         tmp.name[sizeof(tmp.name) - 1] = '\0';
1555
1556         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1557         if (!t)
1558                 return ret;
1559
1560         switch (cmd) {
1561         case EBT_SO_GET_INFO:
1562         case EBT_SO_GET_INIT_INFO:
1563                 if (*len != sizeof(struct ebt_replace)) {
1564                         ret = -EINVAL;
1565                         mutex_unlock(&ebt_mutex);
1566                         break;
1567                 }
1568                 if (cmd == EBT_SO_GET_INFO) {
1569                         tmp.nentries = t->private->nentries;
1570                         tmp.entries_size = t->private->entries_size;
1571                         tmp.valid_hooks = t->valid_hooks;
1572                 } else {
1573                         tmp.nentries = t->table->nentries;
1574                         tmp.entries_size = t->table->entries_size;
1575                         tmp.valid_hooks = t->table->valid_hooks;
1576                 }
1577                 mutex_unlock(&ebt_mutex);
1578                 if (copy_to_user(user, &tmp, *len) != 0) {
1579                         BUGPRINT("c2u Didn't work\n");
1580                         ret = -EFAULT;
1581                         break;
1582                 }
1583                 ret = 0;
1584                 break;
1585
1586         case EBT_SO_GET_ENTRIES:
1587         case EBT_SO_GET_INIT_ENTRIES:
1588                 ret = copy_everything_to_user(t, user, len, cmd);
1589                 mutex_unlock(&ebt_mutex);
1590                 break;
1591
1592         default:
1593                 mutex_unlock(&ebt_mutex);
1594                 ret = -EINVAL;
1595         }
1596
1597         return ret;
1598 }
1599
1600 #ifdef CONFIG_COMPAT
1601 /* 32 bit-userspace compatibility definitions. */
1602 struct compat_ebt_replace {
1603         char name[EBT_TABLE_MAXNAMELEN];
1604         compat_uint_t valid_hooks;
1605         compat_uint_t nentries;
1606         compat_uint_t entries_size;
1607         /* start of the chains */
1608         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1609         /* nr of counters userspace expects back */
1610         compat_uint_t num_counters;
1611         /* where the kernel will put the old counters. */
1612         compat_uptr_t counters;
1613         compat_uptr_t entries;
1614 };
1615
1616 /* struct ebt_entry_match, _target and _watcher have same layout */
1617 struct compat_ebt_entry_mwt {
1618         union {
1619                 struct {
1620                         char name[EBT_EXTENSION_MAXNAMELEN];
1621                         u8 revision;
1622                 };
1623                 compat_uptr_t ptr;
1624         } u;
1625         compat_uint_t match_size;
1626         compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace))));
1627 };
1628
1629 /* account for possible padding between match_size and ->data */
1630 static int ebt_compat_entry_padsize(void)
1631 {
1632         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1633                         sizeof(struct compat_ebt_entry_mwt));
1634         return (int) sizeof(struct ebt_entry_match) -
1635                         sizeof(struct compat_ebt_entry_mwt);
1636 }
1637
1638 static int ebt_compat_match_offset(const struct xt_match *match,
1639                                    unsigned int userlen)
1640 {
1641         /* ebt_among needs special handling. The kernel .matchsize is
1642          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1643          * value is expected.
1644          * Example: userspace sends 4500, ebt_among.c wants 4504.
1645          */
1646         if (unlikely(match->matchsize == -1))
1647                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1648         return xt_compat_match_offset(match);
1649 }
1650
1651 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1652                                 unsigned int *size)
1653 {
1654         const struct xt_match *match = m->u.match;
1655         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1656         int off = ebt_compat_match_offset(match, m->match_size);
1657         compat_uint_t msize = m->match_size - off;
1658
1659         if (WARN_ON(off >= m->match_size))
1660                 return -EINVAL;
1661
1662         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1663             put_user(match->revision, &cm->u.revision) ||
1664             put_user(msize, &cm->match_size))
1665                 return -EFAULT;
1666
1667         if (match->compat_to_user) {
1668                 if (match->compat_to_user(cm->data, m->data))
1669                         return -EFAULT;
1670         } else {
1671                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1672                                     COMPAT_XT_ALIGN(msize)))
1673                         return -EFAULT;
1674         }
1675
1676         *size -= ebt_compat_entry_padsize() + off;
1677         *dstptr = cm->data;
1678         *dstptr += msize;
1679         return 0;
1680 }
1681
1682 static int compat_target_to_user(struct ebt_entry_target *t,
1683                                  void __user **dstptr,
1684                                  unsigned int *size)
1685 {
1686         const struct xt_target *target = t->u.target;
1687         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1688         int off = xt_compat_target_offset(target);
1689         compat_uint_t tsize = t->target_size - off;
1690
1691         if (WARN_ON(off >= t->target_size))
1692                 return -EINVAL;
1693
1694         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1695             put_user(target->revision, &cm->u.revision) ||
1696             put_user(tsize, &cm->match_size))
1697                 return -EFAULT;
1698
1699         if (target->compat_to_user) {
1700                 if (target->compat_to_user(cm->data, t->data))
1701                         return -EFAULT;
1702         } else {
1703                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1704                                     COMPAT_XT_ALIGN(tsize)))
1705                         return -EFAULT;
1706         }
1707
1708         *size -= ebt_compat_entry_padsize() + off;
1709         *dstptr = cm->data;
1710         *dstptr += tsize;
1711         return 0;
1712 }
1713
1714 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1715                                   void __user **dstptr,
1716                                   unsigned int *size)
1717 {
1718         return compat_target_to_user((struct ebt_entry_target *)w,
1719                                                         dstptr, size);
1720 }
1721
1722 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1723                                 unsigned int *size)
1724 {
1725         struct ebt_entry_target *t;
1726         struct ebt_entry __user *ce;
1727         u32 watchers_offset, target_offset, next_offset;
1728         compat_uint_t origsize;
1729         int ret;
1730
1731         if (e->bitmask == 0) {
1732                 if (*size < sizeof(struct ebt_entries))
1733                         return -EINVAL;
1734                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1735                         return -EFAULT;
1736
1737                 *dstptr += sizeof(struct ebt_entries);
1738                 *size -= sizeof(struct ebt_entries);
1739                 return 0;
1740         }
1741
1742         if (*size < sizeof(*ce))
1743                 return -EINVAL;
1744
1745         ce = *dstptr;
1746         if (copy_to_user(ce, e, sizeof(*ce)))
1747                 return -EFAULT;
1748
1749         origsize = *size;
1750         *dstptr += sizeof(*ce);
1751
1752         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1753         if (ret)
1754                 return ret;
1755         watchers_offset = e->watchers_offset - (origsize - *size);
1756
1757         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1758         if (ret)
1759                 return ret;
1760         target_offset = e->target_offset - (origsize - *size);
1761
1762         t = ebt_get_target(e);
1763
1764         ret = compat_target_to_user(t, dstptr, size);
1765         if (ret)
1766                 return ret;
1767         next_offset = e->next_offset - (origsize - *size);
1768
1769         if (put_user(watchers_offset, &ce->watchers_offset) ||
1770             put_user(target_offset, &ce->target_offset) ||
1771             put_user(next_offset, &ce->next_offset))
1772                 return -EFAULT;
1773
1774         *size -= sizeof(*ce);
1775         return 0;
1776 }
1777
1778 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1779 {
1780         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1781         *off += ebt_compat_entry_padsize();
1782         return 0;
1783 }
1784
1785 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1786 {
1787         *off += xt_compat_target_offset(w->u.watcher);
1788         *off += ebt_compat_entry_padsize();
1789         return 0;
1790 }
1791
1792 static int compat_calc_entry(const struct ebt_entry *e,
1793                              const struct ebt_table_info *info,
1794                              const void *base,
1795                              struct compat_ebt_replace *newinfo)
1796 {
1797         const struct ebt_entry_target *t;
1798         unsigned int entry_offset;
1799         int off, ret, i;
1800
1801         if (e->bitmask == 0)
1802                 return 0;
1803
1804         off = 0;
1805         entry_offset = (void *)e - base;
1806
1807         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1808         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1809
1810         t = ebt_get_target_c(e);
1811
1812         off += xt_compat_target_offset(t->u.target);
1813         off += ebt_compat_entry_padsize();
1814
1815         newinfo->entries_size -= off;
1816
1817         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1818         if (ret)
1819                 return ret;
1820
1821         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1822                 const void *hookptr = info->hook_entry[i];
1823                 if (info->hook_entry[i] &&
1824                     (e < (struct ebt_entry *)(base - hookptr))) {
1825                         newinfo->hook_entry[i] -= off;
1826                         pr_debug("0x%08X -> 0x%08X\n",
1827                                         newinfo->hook_entry[i] + off,
1828                                         newinfo->hook_entry[i]);
1829                 }
1830         }
1831
1832         return 0;
1833 }
1834
1835
1836 static int compat_table_info(const struct ebt_table_info *info,
1837                              struct compat_ebt_replace *newinfo)
1838 {
1839         unsigned int size = info->entries_size;
1840         const void *entries = info->entries;
1841
1842         newinfo->entries_size = size;
1843         if (info->nentries) {
1844                 int ret = xt_compat_init_offsets(NFPROTO_BRIDGE,
1845                                                  info->nentries);
1846                 if (ret)
1847                         return ret;
1848         }
1849
1850         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1851                                                         entries, newinfo);
1852 }
1853
1854 static int compat_copy_everything_to_user(struct ebt_table *t,
1855                                           void __user *user, int *len, int cmd)
1856 {
1857         struct compat_ebt_replace repl, tmp;
1858         struct ebt_counter *oldcounters;
1859         struct ebt_table_info tinfo;
1860         int ret;
1861         void __user *pos;
1862
1863         memset(&tinfo, 0, sizeof(tinfo));
1864
1865         if (cmd == EBT_SO_GET_ENTRIES) {
1866                 tinfo.entries_size = t->private->entries_size;
1867                 tinfo.nentries = t->private->nentries;
1868                 tinfo.entries = t->private->entries;
1869                 oldcounters = t->private->counters;
1870         } else {
1871                 tinfo.entries_size = t->table->entries_size;
1872                 tinfo.nentries = t->table->nentries;
1873                 tinfo.entries = t->table->entries;
1874                 oldcounters = t->table->counters;
1875         }
1876
1877         if (copy_from_user(&tmp, user, sizeof(tmp)))
1878                 return -EFAULT;
1879
1880         if (tmp.nentries != tinfo.nentries ||
1881            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1882                 return -EINVAL;
1883
1884         memcpy(&repl, &tmp, sizeof(repl));
1885         if (cmd == EBT_SO_GET_ENTRIES)
1886                 ret = compat_table_info(t->private, &repl);
1887         else
1888                 ret = compat_table_info(&tinfo, &repl);
1889         if (ret)
1890                 return ret;
1891
1892         if (*len != sizeof(tmp) + repl.entries_size +
1893            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1894                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1895                                 *len, tinfo.entries_size, repl.entries_size);
1896                 return -EINVAL;
1897         }
1898
1899         /* userspace might not need the counters */
1900         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1901                                         tmp.num_counters, tinfo.nentries);
1902         if (ret)
1903                 return ret;
1904
1905         pos = compat_ptr(tmp.entries);
1906         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1907                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1908 }
1909
1910 struct ebt_entries_buf_state {
1911         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1912         u32 buf_kern_len;       /* total size of kernel buffer */
1913         u32 buf_kern_offset;    /* amount of data copied so far */
1914         u32 buf_user_offset;    /* read position in userspace buffer */
1915 };
1916
1917 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1918 {
1919         state->buf_kern_offset += sz;
1920         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1921 }
1922
1923 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1924                        void *data, unsigned int sz)
1925 {
1926         if (state->buf_kern_start == NULL)
1927                 goto count_only;
1928
1929         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1930                 return -EINVAL;
1931
1932         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1933
1934  count_only:
1935         state->buf_user_offset += sz;
1936         return ebt_buf_count(state, sz);
1937 }
1938
1939 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1940 {
1941         char *b = state->buf_kern_start;
1942
1943         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1944                 return -EINVAL;
1945
1946         if (b != NULL && sz > 0)
1947                 memset(b + state->buf_kern_offset, 0, sz);
1948         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1949         return ebt_buf_count(state, sz);
1950 }
1951
1952 enum compat_mwt {
1953         EBT_COMPAT_MATCH,
1954         EBT_COMPAT_WATCHER,
1955         EBT_COMPAT_TARGET,
1956 };
1957
1958 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1959                                 enum compat_mwt compat_mwt,
1960                                 struct ebt_entries_buf_state *state,
1961                                 const unsigned char *base)
1962 {
1963         char name[EBT_EXTENSION_MAXNAMELEN];
1964         struct xt_match *match;
1965         struct xt_target *wt;
1966         void *dst = NULL;
1967         int off, pad = 0;
1968         unsigned int size_kern, match_size = mwt->match_size;
1969
1970         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1971                 return -EINVAL;
1972
1973         if (state->buf_kern_start)
1974                 dst = state->buf_kern_start + state->buf_kern_offset;
1975
1976         switch (compat_mwt) {
1977         case EBT_COMPAT_MATCH:
1978                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1979                                               mwt->u.revision);
1980                 if (IS_ERR(match))
1981                         return PTR_ERR(match);
1982
1983                 off = ebt_compat_match_offset(match, match_size);
1984                 if (dst) {
1985                         if (match->compat_from_user)
1986                                 match->compat_from_user(dst, mwt->data);
1987                         else
1988                                 memcpy(dst, mwt->data, match_size);
1989                 }
1990
1991                 size_kern = match->matchsize;
1992                 if (unlikely(size_kern == -1))
1993                         size_kern = match_size;
1994                 module_put(match->me);
1995                 break;
1996         case EBT_COMPAT_WATCHER: /* fallthrough */
1997         case EBT_COMPAT_TARGET:
1998                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1999                                             mwt->u.revision);
2000                 if (IS_ERR(wt))
2001                         return PTR_ERR(wt);
2002                 off = xt_compat_target_offset(wt);
2003
2004                 if (dst) {
2005                         if (wt->compat_from_user)
2006                                 wt->compat_from_user(dst, mwt->data);
2007                         else
2008                                 memcpy(dst, mwt->data, match_size);
2009                 }
2010
2011                 size_kern = wt->targetsize;
2012                 module_put(wt->me);
2013                 break;
2014
2015         default:
2016                 return -EINVAL;
2017         }
2018
2019         state->buf_kern_offset += match_size + off;
2020         state->buf_user_offset += match_size;
2021         pad = XT_ALIGN(size_kern) - size_kern;
2022
2023         if (pad > 0 && dst) {
2024                 if (WARN_ON(state->buf_kern_len <= pad))
2025                         return -EINVAL;
2026                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2027                         return -EINVAL;
2028                 memset(dst + size_kern, 0, pad);
2029         }
2030         return off + match_size;
2031 }
2032
2033 /* return size of all matches, watchers or target, including necessary
2034  * alignment and padding.
2035  */
2036 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2037                         unsigned int size_left, enum compat_mwt type,
2038                         struct ebt_entries_buf_state *state, const void *base)
2039 {
2040         int growth = 0;
2041         char *buf;
2042
2043         if (size_left == 0)
2044                 return 0;
2045
2046         buf = (char *) match32;
2047
2048         while (size_left >= sizeof(*match32)) {
2049                 struct ebt_entry_match *match_kern;
2050                 int ret;
2051
2052                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2053                 if (match_kern) {
2054                         char *tmp;
2055                         tmp = state->buf_kern_start + state->buf_kern_offset;
2056                         match_kern = (struct ebt_entry_match *) tmp;
2057                 }
2058                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2059                 if (ret < 0)
2060                         return ret;
2061                 size_left -= sizeof(*match32);
2062
2063                 /* add padding before match->data (if any) */
2064                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2065                 if (ret < 0)
2066                         return ret;
2067
2068                 if (match32->match_size > size_left)
2069                         return -EINVAL;
2070
2071                 size_left -= match32->match_size;
2072
2073                 ret = compat_mtw_from_user(match32, type, state, base);
2074                 if (ret < 0)
2075                         return ret;
2076
2077                 if (WARN_ON(ret < match32->match_size))
2078                         return -EINVAL;
2079                 growth += ret - match32->match_size;
2080                 growth += ebt_compat_entry_padsize();
2081
2082                 buf += sizeof(*match32);
2083                 buf += match32->match_size;
2084
2085                 if (match_kern)
2086                         match_kern->match_size = ret;
2087
2088                 if (WARN_ON(type == EBT_COMPAT_TARGET && size_left))
2089                         return -EINVAL;
2090
2091                 match32 = (struct compat_ebt_entry_mwt *) buf;
2092         }
2093
2094         return growth;
2095 }
2096
2097 /* called for all ebt_entry structures. */
2098 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2099                           unsigned int *total,
2100                           struct ebt_entries_buf_state *state)
2101 {
2102         unsigned int i, j, startoff, new_offset = 0;
2103         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2104         unsigned int offsets[4];
2105         unsigned int *offsets_update = NULL;
2106         int ret;
2107         char *buf_start;
2108
2109         if (*total < sizeof(struct ebt_entries))
2110                 return -EINVAL;
2111
2112         if (!entry->bitmask) {
2113                 *total -= sizeof(struct ebt_entries);
2114                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2115         }
2116         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2117                 return -EINVAL;
2118
2119         startoff = state->buf_user_offset;
2120         /* pull in most part of ebt_entry, it does not need to be changed. */
2121         ret = ebt_buf_add(state, entry,
2122                         offsetof(struct ebt_entry, watchers_offset));
2123         if (ret < 0)
2124                 return ret;
2125
2126         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2127         memcpy(&offsets[1], &entry->watchers_offset,
2128                         sizeof(offsets) - sizeof(offsets[0]));
2129
2130         if (state->buf_kern_start) {
2131                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2132                 offsets_update = (unsigned int *) buf_start;
2133         }
2134         ret = ebt_buf_add(state, &offsets[1],
2135                         sizeof(offsets) - sizeof(offsets[0]));
2136         if (ret < 0)
2137                 return ret;
2138         buf_start = (char *) entry;
2139         /* 0: matches offset, always follows ebt_entry.
2140          * 1: watchers offset, from ebt_entry structure
2141          * 2: target offset, from ebt_entry structure
2142          * 3: next ebt_entry offset, from ebt_entry structure
2143          *
2144          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2145          */
2146         for (i = 0; i < 4 ; ++i) {
2147                 if (offsets[i] > *total)
2148                         return -EINVAL;
2149
2150                 if (i < 3 && offsets[i] == *total)
2151                         return -EINVAL;
2152
2153                 if (i == 0)
2154                         continue;
2155                 if (offsets[i-1] > offsets[i])
2156                         return -EINVAL;
2157         }
2158
2159         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2160                 struct compat_ebt_entry_mwt *match32;
2161                 unsigned int size;
2162                 char *buf = buf_start + offsets[i];
2163
2164                 if (offsets[i] > offsets[j])
2165                         return -EINVAL;
2166
2167                 match32 = (struct compat_ebt_entry_mwt *) buf;
2168                 size = offsets[j] - offsets[i];
2169                 ret = ebt_size_mwt(match32, size, i, state, base);
2170                 if (ret < 0)
2171                         return ret;
2172                 new_offset += ret;
2173                 if (offsets_update && new_offset) {
2174                         pr_debug("change offset %d to %d\n",
2175                                 offsets_update[i], offsets[j] + new_offset);
2176                         offsets_update[i] = offsets[j] + new_offset;
2177                 }
2178         }
2179
2180         if (state->buf_kern_start == NULL) {
2181                 unsigned int offset = buf_start - (char *) base;
2182
2183                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2184                 if (ret < 0)
2185                         return ret;
2186         }
2187
2188         startoff = state->buf_user_offset - startoff;
2189
2190         if (WARN_ON(*total < startoff))
2191                 return -EINVAL;
2192         *total -= startoff;
2193         return 0;
2194 }
2195
2196 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2197  * It might need more memory when copied to a 64 bit kernel in case
2198  * userspace is 32-bit. So, first task: find out how much memory is needed.
2199  *
2200  * Called before validation is performed.
2201  */
2202 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2203                                 struct ebt_entries_buf_state *state)
2204 {
2205         unsigned int size_remaining = size_user;
2206         int ret;
2207
2208         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2209                                         &size_remaining, state);
2210         if (ret < 0)
2211                 return ret;
2212
2213         WARN_ON(size_remaining);
2214         return state->buf_kern_offset;
2215 }
2216
2217
2218 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2219                                             void __user *user, unsigned int len)
2220 {
2221         struct compat_ebt_replace tmp;
2222         int i;
2223
2224         if (len < sizeof(tmp))
2225                 return -EINVAL;
2226
2227         if (copy_from_user(&tmp, user, sizeof(tmp)))
2228                 return -EFAULT;
2229
2230         if (len != sizeof(tmp) + tmp.entries_size)
2231                 return -EINVAL;
2232
2233         if (tmp.entries_size == 0)
2234                 return -EINVAL;
2235
2236         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2237                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2238                 return -ENOMEM;
2239         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2240                 return -ENOMEM;
2241
2242         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2243
2244         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2245         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2246                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2247
2248         repl->num_counters = tmp.num_counters;
2249         repl->counters = compat_ptr(tmp.counters);
2250         repl->entries = compat_ptr(tmp.entries);
2251         return 0;
2252 }
2253
2254 static int compat_do_replace(struct net *net, void __user *user,
2255                              unsigned int len)
2256 {
2257         int ret, i, countersize, size64;
2258         struct ebt_table_info *newinfo;
2259         struct ebt_replace tmp;
2260         struct ebt_entries_buf_state state;
2261         void *entries_tmp;
2262
2263         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2264         if (ret) {
2265                 /* try real handler in case userland supplied needed padding */
2266                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2267                         ret = 0;
2268                 return ret;
2269         }
2270
2271         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2272         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2273         if (!newinfo)
2274                 return -ENOMEM;
2275
2276         if (countersize)
2277                 memset(newinfo->counters, 0, countersize);
2278
2279         memset(&state, 0, sizeof(state));
2280
2281         newinfo->entries = vmalloc(tmp.entries_size);
2282         if (!newinfo->entries) {
2283                 ret = -ENOMEM;
2284                 goto free_newinfo;
2285         }
2286         if (copy_from_user(
2287            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2288                 ret = -EFAULT;
2289                 goto free_entries;
2290         }
2291
2292         entries_tmp = newinfo->entries;
2293
2294         xt_compat_lock(NFPROTO_BRIDGE);
2295
2296         ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2297         if (ret < 0)
2298                 goto out_unlock;
2299         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2300         if (ret < 0)
2301                 goto out_unlock;
2302
2303         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2304                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2305                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2306
2307         size64 = ret;
2308         newinfo->entries = vmalloc(size64);
2309         if (!newinfo->entries) {
2310                 vfree(entries_tmp);
2311                 ret = -ENOMEM;
2312                 goto out_unlock;
2313         }
2314
2315         memset(&state, 0, sizeof(state));
2316         state.buf_kern_start = newinfo->entries;
2317         state.buf_kern_len = size64;
2318
2319         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2320         if (WARN_ON(ret < 0))
2321                 goto out_unlock;
2322
2323         vfree(entries_tmp);
2324         tmp.entries_size = size64;
2325
2326         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2327                 char __user *usrptr;
2328                 if (tmp.hook_entry[i]) {
2329                         unsigned int delta;
2330                         usrptr = (char __user *) tmp.hook_entry[i];
2331                         delta = usrptr - tmp.entries;
2332                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2333                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2334                 }
2335         }
2336
2337         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2338         xt_compat_unlock(NFPROTO_BRIDGE);
2339
2340         ret = do_replace_finish(net, &tmp, newinfo);
2341         if (ret == 0)
2342                 return ret;
2343 free_entries:
2344         vfree(newinfo->entries);
2345 free_newinfo:
2346         vfree(newinfo);
2347         return ret;
2348 out_unlock:
2349         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2350         xt_compat_unlock(NFPROTO_BRIDGE);
2351         goto free_entries;
2352 }
2353
2354 static int compat_update_counters(struct net *net, void __user *user,
2355                                   unsigned int len)
2356 {
2357         struct compat_ebt_replace hlp;
2358
2359         if (copy_from_user(&hlp, user, sizeof(hlp)))
2360                 return -EFAULT;
2361
2362         /* try real handler in case userland supplied needed padding */
2363         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2364                 return update_counters(net, user, len);
2365
2366         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2367                                         hlp.num_counters, user, len);
2368 }
2369
2370 static int compat_do_ebt_set_ctl(struct sock *sk,
2371                 int cmd, void __user *user, unsigned int len)
2372 {
2373         int ret;
2374         struct net *net = sock_net(sk);
2375
2376         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2377                 return -EPERM;
2378
2379         switch (cmd) {
2380         case EBT_SO_SET_ENTRIES:
2381                 ret = compat_do_replace(net, user, len);
2382                 break;
2383         case EBT_SO_SET_COUNTERS:
2384                 ret = compat_update_counters(net, user, len);
2385                 break;
2386         default:
2387                 ret = -EINVAL;
2388         }
2389         return ret;
2390 }
2391
2392 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2393                 void __user *user, int *len)
2394 {
2395         int ret;
2396         struct compat_ebt_replace tmp;
2397         struct ebt_table *t;
2398         struct net *net = sock_net(sk);
2399
2400         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2401                 return -EPERM;
2402
2403         /* try real handler in case userland supplied needed padding */
2404         if ((cmd == EBT_SO_GET_INFO ||
2405              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2406                         return do_ebt_get_ctl(sk, cmd, user, len);
2407
2408         if (copy_from_user(&tmp, user, sizeof(tmp)))
2409                 return -EFAULT;
2410
2411         tmp.name[sizeof(tmp.name) - 1] = '\0';
2412
2413         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2414         if (!t)
2415                 return ret;
2416
2417         xt_compat_lock(NFPROTO_BRIDGE);
2418         switch (cmd) {
2419         case EBT_SO_GET_INFO:
2420                 tmp.nentries = t->private->nentries;
2421                 ret = compat_table_info(t->private, &tmp);
2422                 if (ret)
2423                         goto out;
2424                 tmp.valid_hooks = t->valid_hooks;
2425
2426                 if (copy_to_user(user, &tmp, *len) != 0) {
2427                         ret = -EFAULT;
2428                         break;
2429                 }
2430                 ret = 0;
2431                 break;
2432         case EBT_SO_GET_INIT_INFO:
2433                 tmp.nentries = t->table->nentries;
2434                 tmp.entries_size = t->table->entries_size;
2435                 tmp.valid_hooks = t->table->valid_hooks;
2436
2437                 if (copy_to_user(user, &tmp, *len) != 0) {
2438                         ret = -EFAULT;
2439                         break;
2440                 }
2441                 ret = 0;
2442                 break;
2443         case EBT_SO_GET_ENTRIES:
2444         case EBT_SO_GET_INIT_ENTRIES:
2445                 /* try real handler first in case of userland-side padding.
2446                  * in case we are dealing with an 'ordinary' 32 bit binary
2447                  * without 64bit compatibility padding, this will fail right
2448                  * after copy_from_user when the *len argument is validated.
2449                  *
2450                  * the compat_ variant needs to do one pass over the kernel
2451                  * data set to adjust for size differences before it the check.
2452                  */
2453                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2454                         ret = 0;
2455                 else
2456                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2457                 break;
2458         default:
2459                 ret = -EINVAL;
2460         }
2461  out:
2462         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2463         xt_compat_unlock(NFPROTO_BRIDGE);
2464         mutex_unlock(&ebt_mutex);
2465         return ret;
2466 }
2467 #endif
2468
2469 static struct nf_sockopt_ops ebt_sockopts = {
2470         .pf             = PF_INET,
2471         .set_optmin     = EBT_BASE_CTL,
2472         .set_optmax     = EBT_SO_SET_MAX + 1,
2473         .set            = do_ebt_set_ctl,
2474 #ifdef CONFIG_COMPAT
2475         .compat_set     = compat_do_ebt_set_ctl,
2476 #endif
2477         .get_optmin     = EBT_BASE_CTL,
2478         .get_optmax     = EBT_SO_GET_MAX + 1,
2479         .get            = do_ebt_get_ctl,
2480 #ifdef CONFIG_COMPAT
2481         .compat_get     = compat_do_ebt_get_ctl,
2482 #endif
2483         .owner          = THIS_MODULE,
2484 };
2485
2486 static int __init ebtables_init(void)
2487 {
2488         int ret;
2489
2490         ret = xt_register_target(&ebt_standard_target);
2491         if (ret < 0)
2492                 return ret;
2493         ret = nf_register_sockopt(&ebt_sockopts);
2494         if (ret < 0) {
2495                 xt_unregister_target(&ebt_standard_target);
2496                 return ret;
2497         }
2498
2499         return 0;
2500 }
2501
2502 static void __exit ebtables_fini(void)
2503 {
2504         nf_unregister_sockopt(&ebt_sockopts);
2505         xt_unregister_target(&ebt_standard_target);
2506 }
2507
2508 EXPORT_SYMBOL(ebt_register_table);
2509 EXPORT_SYMBOL(ebt_unregister_table);
2510 EXPORT_SYMBOL(ebt_do_table);
2511 module_init(ebtables_init);
2512 module_exit(ebtables_fini);
2513 MODULE_LICENSE("GPL");