net/bridge/netfilter/ebtables.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ebtables
   4  *
   5  *  Author:
   6  *  Bart De Schuymer            <[email protected]>
   7  *
   8  *  ebtables.c,v 2.0, July, 2002
   9  *
  10  *  This code is strongly inspired by the iptables code which is
  11  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  12  */
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/kmod.h>
  15 #include <linux/module.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/netfilter/x_tables.h>
  18 #include <linux/netfilter_bridge/ebtables.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/mutex.h>
  21 #include <linux/slab.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/smp.h>
  24 #include <linux/cpumask.h>
  25 #include <linux/audit.h>
  26 #include <net/sock.h>
  27 /* needed for logical [in,out]-dev filtering */
  28 #include "../br_private.h"
  29
  30 /* Each cpu has its own set of counters, so there is no need for write_lock in
  31  * the softirq
  32  * For reading or updating the counters, the user context needs to
  33  * get a write_lock
  34  */
  35
  36 /* The size of each set of counters is altered to get cache alignment */
  37 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  38 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  39 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  40                                  COUNTER_OFFSET(n) * cpu))
  41
  42
  43
  44 static DEFINE_MUTEX(ebt_mutex);
  45
  46 #ifdef CONFIG_COMPAT
  47 static void ebt_standard_compat_from_user(void *dst, const void *src)
  48 {
  49         int v = *(compat_int_t *)src;
  50
  51         if (v >= 0)
  52                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  53         memcpy(dst, &v, sizeof(v));
  54 }
  55
  56 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  57 {
  58         compat_int_t cv = *(int *)src;
  59
  60         if (cv >= 0)
  61                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  62         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  63 }
  64 #endif
  65
  66
  67 static struct xt_target ebt_standard_target = {
  68         .name       = "standard",
  69         .revision   = 0,
  70         .family     = NFPROTO_BRIDGE,
  71         .targetsize = sizeof(int),
  72 #ifdef CONFIG_COMPAT
  73         .compatsize = sizeof(compat_int_t),
  74         .compat_from_user = ebt_standard_compat_from_user,
  75         .compat_to_user =  ebt_standard_compat_to_user,
  76 #endif
  77 };
  78
  79 static inline int
  80 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  81                struct xt_action_param *par)
  82 {
  83         par->target   = w->u.watcher;
  84         par->targinfo = w->data;
  85         w->u.watcher->target(skb, par);
  86         /* watchers don't give a verdict */
  87         return 0;
  88 }
  89
  90 static inline int
  91 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
  92              struct xt_action_param *par)
  93 {
  94         par->match     = m->u.match;
  95         par->matchinfo = m->data;
  96         return !m->u.match->match(skb, par);
  97 }
  98
  99 static inline int
 100 ebt_dev_check(const char *entry, const struct net_device *device)
 101 {
 102         int i = 0;
 103         const char *devname;
 104
 105         if (*entry == '\0')
 106                 return 0;
 107         if (!device)
 108                 return 1;
 109         devname = device->name;
 110         /* 1 is the wildcard token */
 111         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 112                 i++;
 113         return devname[i] != entry[i] && entry[i] != 1;
 114 }
 115
 116 /* process standard matches */
 117 static inline int
 118 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 119                 const struct net_device *in, const struct net_device *out)
 120 {
 121         const struct ethhdr *h = eth_hdr(skb);
 122         const struct net_bridge_port *p;
 123         __be16 ethproto;
 124
 125         if (skb_vlan_tag_present(skb))
 126                 ethproto = htons(ETH_P_8021Q);
 127         else
 128                 ethproto = h->h_proto;
 129
 130         if (e->bitmask & EBT_802_3) {
 131                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 132                         return 1;
 133         } else if (!(e->bitmask & EBT_NOPROTO) &&
 134                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 135                 return 1;
 136
 137         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 138                 return 1;
 139         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 140                 return 1;
 141         /* rcu_read_lock()ed by nf_hook_thresh */
 142         if (in && (p = br_port_get_rcu(in)) != NULL &&
 143             NF_INVF(e, EBT_ILOGICALIN,
 144                     ebt_dev_check(e->logical_in, p->br->dev)))
 145                 return 1;
 146         if (out && (p = br_port_get_rcu(out)) != NULL &&
 147             NF_INVF(e, EBT_ILOGICALOUT,
 148                     ebt_dev_check(e->logical_out, p->br->dev)))
 149                 return 1;
 150
 151         if (e->bitmask & EBT_SOURCEMAC) {
 152                 if (NF_INVF(e, EBT_ISOURCE,
 153                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 154                                                      e->sourcemsk)))
 155                         return 1;
 156         }
 157         if (e->bitmask & EBT_DESTMAC) {
 158                 if (NF_INVF(e, EBT_IDEST,
 159                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 160                                                      e->destmsk)))
 161                         return 1;
 162         }
 163         return 0;
 164 }
 165
 166 static inline
 167 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 168 {
 169         return (void *)entry + entry->next_offset;
 170 }
 171
 172 static inline const struct ebt_entry_target *
 173 ebt_get_target_c(const struct ebt_entry *e)
 174 {
 175         return ebt_get_target((struct ebt_entry *)e);
 176 }
 177
 178 /* Do some firewalling */
 179 unsigned int ebt_do_table(struct sk_buff *skb,
 180                           const struct nf_hook_state *state,
 181                           struct ebt_table *table)
 182 {
 183         unsigned int hook = state->hook;
 184         int i, nentries;
 185         struct ebt_entry *point;
 186         struct ebt_counter *counter_base, *cb_base;
 187         const struct ebt_entry_target *t;
 188         int verdict, sp = 0;
 189         struct ebt_chainstack *cs;
 190         struct ebt_entries *chaininfo;
 191         const char *base;
 192         const struct ebt_table_info *private;
 193         struct xt_action_param acpar;
 194
 195         acpar.state   = state;
 196         acpar.hotdrop = false;
 197
 198         read_lock_bh(&table->lock);
 199         private = table->private;
 200         cb_base = COUNTER_BASE(private->counters, private->nentries,
 201            smp_processor_id());
 202         if (private->chainstack)
 203                 cs = private->chainstack[smp_processor_id()];
 204         else
 205                 cs = NULL;
 206         chaininfo = private->hook_entry[hook];
 207         nentries = private->hook_entry[hook]->nentries;
 208         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 209         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 210         /* base for chain jumps */
 211         base = private->entries;
 212         i = 0;
 213         while (i < nentries) {
 214                 if (ebt_basic_match(point, skb, state->in, state->out))
 215                         goto letscontinue;
 216
 217                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 218                         goto letscontinue;
 219                 if (acpar.hotdrop) {
 220                         read_unlock_bh(&table->lock);
 221                         return NF_DROP;
 222                 }
 223
 224                 ADD_COUNTER(*(counter_base + i), skb->len, 1);
 225
 226                 /* these should only watch: not modify, nor tell us
 227                  * what to do with the packet
 228                  */
 229                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 230
 231                 t = ebt_get_target_c(point);
 232                 /* standard target */
 233                 if (!t->u.target->target)
 234                         verdict = ((struct ebt_standard_target *)t)->verdict;
 235                 else {
 236                         acpar.target   = t->u.target;
 237                         acpar.targinfo = t->data;
 238                         verdict = t->u.target->target(skb, &acpar);
 239                 }
 240                 if (verdict == EBT_ACCEPT) {
 241                         read_unlock_bh(&table->lock);
 242                         return NF_ACCEPT;
 243                 }
 244                 if (verdict == EBT_DROP) {
 245                         read_unlock_bh(&table->lock);
 246                         return NF_DROP;
 247                 }
 248                 if (verdict == EBT_RETURN) {
 249 letsreturn:
 250                         if (WARN(sp == 0, "RETURN on base chain")) {
 251                                 /* act like this is EBT_CONTINUE */
 252                                 goto letscontinue;
 253                         }
 254
 255                         sp--;
 256                         /* put all the local variables right */
 257                         i = cs[sp].n;
 258                         chaininfo = cs[sp].chaininfo;
 259                         nentries = chaininfo->nentries;
 260                         point = cs[sp].e;
 261                         counter_base = cb_base +
 262                            chaininfo->counter_offset;
 263                         continue;
 264                 }
 265                 if (verdict == EBT_CONTINUE)
 266                         goto letscontinue;
 267
 268                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 269                         read_unlock_bh(&table->lock);
 270                         return NF_DROP;
 271                 }
 272
 273                 /* jump to a udc */
 274                 cs[sp].n = i + 1;
 275                 cs[sp].chaininfo = chaininfo;
 276                 cs[sp].e = ebt_next_entry(point);
 277                 i = 0;
 278                 chaininfo = (struct ebt_entries *) (base + verdict);
 279
 280                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 281                         read_unlock_bh(&table->lock);
 282                         return NF_DROP;
 283                 }
 284
 285                 nentries = chaininfo->nentries;
 286                 point = (struct ebt_entry *)chaininfo->data;
 287                 counter_base = cb_base + chaininfo->counter_offset;
 288                 sp++;
 289                 continue;
 290 letscontinue:
 291                 point = ebt_next_entry(point);
 292                 i++;
 293         }
 294
 295         /* I actually like this :) */
 296         if (chaininfo->policy == EBT_RETURN)
 297                 goto letsreturn;
 298         if (chaininfo->policy == EBT_ACCEPT) {
 299                 read_unlock_bh(&table->lock);
 300                 return NF_ACCEPT;
 301         }
 302         read_unlock_bh(&table->lock);
 303         return NF_DROP;
 304 }
 305
 306 /* If it succeeds, returns element and locks mutex */
 307 static inline void *
 308 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 309                         struct mutex *mutex)
 310 {
 311         struct {
 312                 struct list_head list;
 313                 char name[EBT_FUNCTION_MAXNAMELEN];
 314         } *e;
 315
 316         mutex_lock(mutex);
 317         list_for_each_entry(e, head, list) {
 318                 if (strcmp(e->name, name) == 0)
 319                         return e;
 320         }
 321         *error = -ENOENT;
 322         mutex_unlock(mutex);
 323         return NULL;
 324 }
 325
 326 static void *
 327 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 328                  int *error, struct mutex *mutex)
 329 {
 330         return try_then_request_module(
 331                         find_inlist_lock_noload(head, name, error, mutex),
 332                         "%s%s", prefix, name);
 333 }
 334
 335 static inline struct ebt_table *
 336 find_table_lock(struct net *net, const char *name, int *error,
 337                 struct mutex *mutex)
 338 {
 339         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 340                                 "ebtable_", error, mutex);
 341 }
 342
 343 static inline void ebt_free_table_info(struct ebt_table_info *info)
 344 {
 345         int i;
 346
 347         if (info->chainstack) {
 348                 for_each_possible_cpu(i)
 349                         vfree(info->chainstack[i]);
 350                 vfree(info->chainstack);
 351         }
 352 }
 353 static inline int
 354 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 355                 unsigned int *cnt)
 356 {
 357         const struct ebt_entry *e = par->entryinfo;
 358         struct xt_match *match;
 359         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 360         int ret;
 361
 362         if (left < sizeof(struct ebt_entry_match) ||
 363             left - sizeof(struct ebt_entry_match) < m->match_size)
 364                 return -EINVAL;
 365
 366         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 367         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 368                 if (!IS_ERR(match))
 369                         module_put(match->me);
 370                 request_module("ebt_%s", m->u.name);
 371                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 372         }
 373         if (IS_ERR(match))
 374                 return PTR_ERR(match);
 375         m->u.match = match;
 376
 377         par->match     = match;
 378         par->matchinfo = m->data;
 379         ret = xt_check_match(par, m->match_size,
 380               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 381         if (ret < 0) {
 382                 module_put(match->me);
 383                 return ret;
 384         }
 385
 386         (*cnt)++;
 387         return 0;
 388 }
 389
 390 static inline int
 391 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 392                   unsigned int *cnt)
 393 {
 394         const struct ebt_entry *e = par->entryinfo;
 395         struct xt_target *watcher;
 396         size_t left = ((char *)e + e->target_offset) - (char *)w;
 397         int ret;
 398
 399         if (left < sizeof(struct ebt_entry_watcher) ||
 400            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 401                 return -EINVAL;
 402
 403         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 404         if (IS_ERR(watcher))
 405                 return PTR_ERR(watcher);
 406
 407         if (watcher->family != NFPROTO_BRIDGE) {
 408                 module_put(watcher->me);
 409                 return -ENOENT;
 410         }
 411
 412         w->u.watcher = watcher;
 413
 414         par->target   = watcher;
 415         par->targinfo = w->data;
 416         ret = xt_check_target(par, w->watcher_size,
 417               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 418         if (ret < 0) {
 419                 module_put(watcher->me);
 420                 return ret;
 421         }
 422
 423         (*cnt)++;
 424         return 0;
 425 }
 426
 427 static int ebt_verify_pointers(const struct ebt_replace *repl,
 428                                struct ebt_table_info *newinfo)
 429 {
 430         unsigned int limit = repl->entries_size;
 431         unsigned int valid_hooks = repl->valid_hooks;
 432         unsigned int offset = 0;
 433         int i;
 434
 435         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 436                 newinfo->hook_entry[i] = NULL;
 437
 438         newinfo->entries_size = repl->entries_size;
 439         newinfo->nentries = repl->nentries;
 440
 441         while (offset < limit) {
 442                 size_t left = limit - offset;
 443                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 444
 445                 if (left < sizeof(unsigned int))
 446                         break;
 447
 448                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 449                         if ((valid_hooks & (1 << i)) == 0)
 450                                 continue;
 451                         if ((char __user *)repl->hook_entry[i] ==
 452                              repl->entries + offset)
 453                                 break;
 454                 }
 455
 456                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 457                         if (e->bitmask != 0) {
 458                                 /* we make userspace set this right,
 459                                  * so there is no misunderstanding
 460                                  */
 461                                 return -EINVAL;
 462                         }
 463                         if (i != NF_BR_NUMHOOKS)
 464                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 465                         if (left < sizeof(struct ebt_entries))
 466                                 break;
 467                         offset += sizeof(struct ebt_entries);
 468                 } else {
 469                         if (left < sizeof(struct ebt_entry))
 470                                 break;
 471                         if (left < e->next_offset)
 472                                 break;
 473                         if (e->next_offset < sizeof(struct ebt_entry))
 474                                 return -EINVAL;
 475                         offset += e->next_offset;
 476                 }
 477         }
 478         if (offset != limit)
 479                 return -EINVAL;
 480
 481         /* check if all valid hooks have a chain */
 482         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 483                 if (!newinfo->hook_entry[i] &&
 484                    (valid_hooks & (1 << i)))
 485                         return -EINVAL;
 486         }
 487         return 0;
 488 }
 489
 490 /* this one is very careful, as it is the first function
 491  * to parse the userspace data
 492  */
 493 static inline int
 494 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 495                                const struct ebt_table_info *newinfo,
 496                                unsigned int *n, unsigned int *cnt,
 497                                unsigned int *totalcnt, unsigned int *udc_cnt)
 498 {
 499         int i;
 500
 501         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 502                 if ((void *)e == (void *)newinfo->hook_entry[i])
 503                         break;
 504         }
 505         /* beginning of a new chain
 506          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 507          */
 508         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 509                 /* this checks if the previous chain has as many entries
 510                  * as it said it has
 511                  */
 512                 if (*n != *cnt)
 513                         return -EINVAL;
 514
 515                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 516                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 517                         /* only RETURN from udc */
 518                         if (i != NF_BR_NUMHOOKS ||
 519                            ((struct ebt_entries *)e)->policy != EBT_RETURN)
 520                                 return -EINVAL;
 521                 }
 522                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 523                         (*udc_cnt)++;
 524                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
 525                         return -EINVAL;
 526                 *n = ((struct ebt_entries *)e)->nentries;
 527                 *cnt = 0;
 528                 return 0;
 529         }
 530         /* a plain old entry, heh */
 531         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 532            e->watchers_offset > e->target_offset ||
 533            e->target_offset >= e->next_offset)
 534                 return -EINVAL;
 535
 536         /* this is not checked anywhere else */
 537         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
 538                 return -EINVAL;
 539
 540         (*cnt)++;
 541         (*totalcnt)++;
 542         return 0;
 543 }
 544
 545 struct ebt_cl_stack {
 546         struct ebt_chainstack cs;
 547         int from;
 548         unsigned int hookmask;
 549 };
 550
 551 /* We need these positions to check that the jumps to a different part of the
 552  * entries is a jump to the beginning of a new chain.
 553  */
 554 static inline int
 555 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 556                       unsigned int *n, struct ebt_cl_stack *udc)
 557 {
 558         int i;
 559
 560         /* we're only interested in chain starts */
 561         if (e->bitmask)
 562                 return 0;
 563         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 564                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 565                         break;
 566         }
 567         /* only care about udc */
 568         if (i != NF_BR_NUMHOOKS)
 569                 return 0;
 570
 571         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 572         /* these initialisations are depended on later in check_chainloops() */
 573         udc[*n].cs.n = 0;
 574         udc[*n].hookmask = 0;
 575
 576         (*n)++;
 577         return 0;
 578 }
 579
 580 static inline int
 581 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 582 {
 583         struct xt_mtdtor_param par;
 584
 585         if (i && (*i)-- == 0)
 586                 return 1;
 587
 588         par.net       = net;
 589         par.match     = m->u.match;
 590         par.matchinfo = m->data;
 591         par.family    = NFPROTO_BRIDGE;
 592         if (par.match->destroy != NULL)
 593                 par.match->destroy(&par);
 594         module_put(par.match->me);
 595         return 0;
 596 }
 597
 598 static inline int
 599 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 600 {
 601         struct xt_tgdtor_param par;
 602
 603         if (i && (*i)-- == 0)
 604                 return 1;
 605
 606         par.net      = net;
 607         par.target   = w->u.watcher;
 608         par.targinfo = w->data;
 609         par.family   = NFPROTO_BRIDGE;
 610         if (par.target->destroy != NULL)
 611                 par.target->destroy(&par);
 612         module_put(par.target->me);
 613         return 0;
 614 }
 615
 616 static inline int
 617 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 618 {
 619         struct xt_tgdtor_param par;
 620         struct ebt_entry_target *t;
 621
 622         if (e->bitmask == 0)
 623                 return 0;
 624         /* we're done */
 625         if (cnt && (*cnt)-- == 0)
 626                 return 1;
 627         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 628         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 629         t = ebt_get_target(e);
 630
 631         par.net      = net;
 632         par.target   = t->u.target;
 633         par.targinfo = t->data;
 634         par.family   = NFPROTO_BRIDGE;
 635         if (par.target->destroy != NULL)
 636                 par.target->destroy(&par);
 637         module_put(par.target->me);
 638         return 0;
 639 }
 640
 641 static inline int
 642 ebt_check_entry(struct ebt_entry *e, struct net *net,
 643                 const struct ebt_table_info *newinfo,
 644                 const char *name, unsigned int *cnt,
 645                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 646 {
 647         struct ebt_entry_target *t;
 648         struct xt_target *target;
 649         unsigned int i, j, hook = 0, hookmask = 0;
 650         size_t gap;
 651         int ret;
 652         struct xt_mtchk_param mtpar;
 653         struct xt_tgchk_param tgpar;
 654
 655         /* don't mess with the struct ebt_entries */
 656         if (e->bitmask == 0)
 657                 return 0;
 658
 659         if (e->bitmask & ~EBT_F_MASK)
 660                 return -EINVAL;
 661
 662         if (e->invflags & ~EBT_INV_MASK)
 663                 return -EINVAL;
 664
 665         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
 666                 return -EINVAL;
 667
 668         /* what hook do we belong to? */
 669         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 670                 if (!newinfo->hook_entry[i])
 671                         continue;
 672                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 673                         hook = i;
 674                 else
 675                         break;
 676         }
 677         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 678          * a base chain
 679          */
 680         if (i < NF_BR_NUMHOOKS)
 681                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 682         else {
 683                 for (i = 0; i < udc_cnt; i++)
 684                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 685                                 break;
 686                 if (i == 0)
 687                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 688                 else
 689                         hookmask = cl_s[i - 1].hookmask;
 690         }
 691         i = 0;
 692
 693         memset(&mtpar, 0, sizeof(mtpar));
 694         memset(&tgpar, 0, sizeof(tgpar));
 695         mtpar.net       = tgpar.net       = net;
 696         mtpar.table     = tgpar.table     = name;
 697         mtpar.entryinfo = tgpar.entryinfo = e;
 698         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 699         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 700         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 701         if (ret != 0)
 702                 goto cleanup_matches;
 703         j = 0;
 704         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 705         if (ret != 0)
 706                 goto cleanup_watchers;
 707         t = ebt_get_target(e);
 708         gap = e->next_offset - e->target_offset;
 709
 710         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 711         if (IS_ERR(target)) {
 712                 ret = PTR_ERR(target);
 713                 goto cleanup_watchers;
 714         }
 715
 716         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 717         if (target->family != NFPROTO_BRIDGE) {
 718                 module_put(target->me);
 719                 ret = -ENOENT;
 720                 goto cleanup_watchers;
 721         }
 722
 723         t->u.target = target;
 724         if (t->u.target == &ebt_standard_target) {
 725                 if (gap < sizeof(struct ebt_standard_target)) {
 726                         ret = -EFAULT;
 727                         goto cleanup_watchers;
 728                 }
 729                 if (((struct ebt_standard_target *)t)->verdict <
 730                    -NUM_STANDARD_TARGETS) {
 731                         ret = -EFAULT;
 732                         goto cleanup_watchers;
 733                 }
 734         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 735                 module_put(t->u.target->me);
 736                 ret = -EFAULT;
 737                 goto cleanup_watchers;
 738         }
 739
 740         tgpar.target   = target;
 741         tgpar.targinfo = t->data;
 742         ret = xt_check_target(&tgpar, t->target_size,
 743               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 744         if (ret < 0) {
 745                 module_put(target->me);
 746                 goto cleanup_watchers;
 747         }
 748         (*cnt)++;
 749         return 0;
 750 cleanup_watchers:
 751         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 752 cleanup_matches:
 753         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 754         return ret;
 755 }
 756
 757 /* checks for loops and sets the hook mask for udc
 758  * the hook mask for udc tells us from which base chains the udc can be
 759  * accessed. This mask is a parameter to the check() functions of the extensions
 760  */
 761 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 762                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 763 {
 764         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 765         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 766         const struct ebt_entry_target *t;
 767
 768         while (pos < nentries || chain_nr != -1) {
 769                 /* end of udc, go back one 'recursion' step */
 770                 if (pos == nentries) {
 771                         /* put back values of the time when this chain was called */
 772                         e = cl_s[chain_nr].cs.e;
 773                         if (cl_s[chain_nr].from != -1)
 774                                 nentries =
 775                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 776                         else
 777                                 nentries = chain->nentries;
 778                         pos = cl_s[chain_nr].cs.n;
 779                         /* make sure we won't see a loop that isn't one */
 780                         cl_s[chain_nr].cs.n = 0;
 781                         chain_nr = cl_s[chain_nr].from;
 782                         if (pos == nentries)
 783                                 continue;
 784                 }
 785                 t = ebt_get_target_c(e);
 786                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 787                         goto letscontinue;
 788                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 789                    e->next_offset)
 790                         return -1;
 791
 792                 verdict = ((struct ebt_standard_target *)t)->verdict;
 793                 if (verdict >= 0) { /* jump to another chain */
 794                         struct ebt_entries *hlp2 =
 795                            (struct ebt_entries *)(base + verdict);
 796                         for (i = 0; i < udc_cnt; i++)
 797                                 if (hlp2 == cl_s[i].cs.chaininfo)
 798                                         break;
 799                         /* bad destination or loop */
 800                         if (i == udc_cnt)
 801                                 return -1;
 802
 803                         if (cl_s[i].cs.n)
 804                                 return -1;
 805
 806                         if (cl_s[i].hookmask & (1 << hooknr))
 807                                 goto letscontinue;
 808                         /* this can't be 0, so the loop test is correct */
 809                         cl_s[i].cs.n = pos + 1;
 810                         pos = 0;
 811                         cl_s[i].cs.e = ebt_next_entry(e);
 812                         e = (struct ebt_entry *)(hlp2->data);
 813                         nentries = hlp2->nentries;
 814                         cl_s[i].from = chain_nr;
 815                         chain_nr = i;
 816                         /* this udc is accessible from the base chain for hooknr */
 817                         cl_s[i].hookmask |= (1 << hooknr);
 818                         continue;
 819                 }
 820 letscontinue:
 821                 e = ebt_next_entry(e);
 822                 pos++;
 823         }
 824         return 0;
 825 }
 826
 827 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 828 static int translate_table(struct net *net, const char *name,
 829                            struct ebt_table_info *newinfo)
 830 {
 831         unsigned int i, j, k, udc_cnt;
 832         int ret;
 833         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 834
 835         i = 0;
 836         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 837                 i++;
 838         if (i == NF_BR_NUMHOOKS)
 839                 return -EINVAL;
 840
 841         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
 842                 return -EINVAL;
 843
 844         /* make sure chains are ordered after each other in same order
 845          * as their corresponding hooks
 846          */
 847         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 848                 if (!newinfo->hook_entry[j])
 849                         continue;
 850                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
 851                         return -EINVAL;
 852
 853                 i = j;
 854         }
 855
 856         /* do some early checkings and initialize some things */
 857         i = 0; /* holds the expected nr. of entries for the chain */
 858         j = 0; /* holds the up to now counted entries for the chain */
 859         k = 0; /* holds the total nr. of entries, should equal
 860                 * newinfo->nentries afterwards
 861                 */
 862         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 863         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 864            ebt_check_entry_size_and_hooks, newinfo,
 865            &i, &j, &k, &udc_cnt);
 866
 867         if (ret != 0)
 868                 return ret;
 869
 870         if (i != j)
 871                 return -EINVAL;
 872
 873         if (k != newinfo->nentries)
 874                 return -EINVAL;
 875
 876         /* get the location of the udc, put them in an array
 877          * while we're at it, allocate the chainstack
 878          */
 879         if (udc_cnt) {
 880                 /* this will get free'd in do_replace()/ebt_register_table()
 881                  * if an error occurs
 882                  */
 883                 newinfo->chainstack =
 884                         vmalloc(array_size(nr_cpu_ids,
 885                                            sizeof(*(newinfo->chainstack))));
 886                 if (!newinfo->chainstack)
 887                         return -ENOMEM;
 888                 for_each_possible_cpu(i) {
 889                         newinfo->chainstack[i] =
 890                           vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 891                         if (!newinfo->chainstack[i]) {
 892                                 while (i)
 893                                         vfree(newinfo->chainstack[--i]);
 894                                 vfree(newinfo->chainstack);
 895                                 newinfo->chainstack = NULL;
 896                                 return -ENOMEM;
 897                         }
 898                 }
 899
 900                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 901                 if (!cl_s)
 902                         return -ENOMEM;
 903                 i = 0; /* the i'th udc */
 904                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 905                    ebt_get_udc_positions, newinfo, &i, cl_s);
 906                 /* sanity check */
 907                 if (i != udc_cnt) {
 908                         vfree(cl_s);
 909                         return -EFAULT;
 910                 }
 911         }
 912
 913         /* Check for loops */
 914         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 915                 if (newinfo->hook_entry[i])
 916                         if (check_chainloops(newinfo->hook_entry[i],
 917                            cl_s, udc_cnt, i, newinfo->entries)) {
 918                                 vfree(cl_s);
 919                                 return -EINVAL;
 920                         }
 921
 922         /* we now know the following (along with E=mc²):
 923          *  - the nr of entries in each chain is right
 924          *  - the size of the allocated space is right
 925          *  - all valid hooks have a corresponding chain
 926          *  - there are no loops
 927          *  - wrong data can still be on the level of a single entry
 928          *  - could be there are jumps to places that are not the
 929          *    beginning of a chain. This can only occur in chains that
 930          *    are not accessible from any base chains, so we don't care.
 931          */
 932
 933         /* used to know what we need to clean up if something goes wrong */
 934         i = 0;
 935         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 936            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 937         if (ret != 0) {
 938                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 939                                   ebt_cleanup_entry, net, &i);
 940         }
 941         vfree(cl_s);
 942         return ret;
 943 }
 944
 945 /* called under write_lock */
 946 static void get_counters(const struct ebt_counter *oldcounters,
 947                          struct ebt_counter *counters, unsigned int nentries)
 948 {
 949         int i, cpu;
 950         struct ebt_counter *counter_base;
 951
 952         /* counters of cpu 0 */
 953         memcpy(counters, oldcounters,
 954                sizeof(struct ebt_counter) * nentries);
 955
 956         /* add other counters to those of cpu 0 */
 957         for_each_possible_cpu(cpu) {
 958                 if (cpu == 0)
 959                         continue;
 960                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 961                 for (i = 0; i < nentries; i++)
 962                         ADD_COUNTER(counters[i], counter_base[i].bcnt,
 963                                     counter_base[i].pcnt);
 964         }
 965 }
 966
 967 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 968                               struct ebt_table_info *newinfo)
 969 {
 970         int ret;
 971         struct ebt_counter *counterstmp = NULL;
 972         /* used to be able to unlock earlier */
 973         struct ebt_table_info *table;
 974         struct ebt_table *t;
 975
 976         /* the user wants counters back
 977          * the check on the size is done later, when we have the lock
 978          */
 979         if (repl->num_counters) {
 980                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 981                 counterstmp = vmalloc(size);
 982                 if (!counterstmp)
 983                         return -ENOMEM;
 984         }
 985
 986         newinfo->chainstack = NULL;
 987         ret = ebt_verify_pointers(repl, newinfo);
 988         if (ret != 0)
 989                 goto free_counterstmp;
 990
 991         ret = translate_table(net, repl->name, newinfo);
 992
 993         if (ret != 0)
 994                 goto free_counterstmp;
 995
 996         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
 997         if (!t) {
 998                 ret = -ENOENT;
 999                 goto free_iterate;
1000         }
1001
1002         /* the table doesn't like it */
1003         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1004                 goto free_unlock;
1005
1006         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1007                 ret = -EINVAL;
1008                 goto free_unlock;
1009         }
1010
1011         /* we have the mutex lock, so no danger in reading this pointer */
1012         table = t->private;
1013         /* make sure the table can only be rmmod'ed if it contains no rules */
1014         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1015                 ret = -ENOENT;
1016                 goto free_unlock;
1017         } else if (table->nentries && !newinfo->nentries)
1018                 module_put(t->me);
1019         /* we need an atomic snapshot of the counters */
1020         write_lock_bh(&t->lock);
1021         if (repl->num_counters)
1022                 get_counters(t->private->counters, counterstmp,
1023                    t->private->nentries);
1024
1025         t->private = newinfo;
1026         write_unlock_bh(&t->lock);
1027         mutex_unlock(&ebt_mutex);
1028         /* so, a user can change the chains while having messed up her counter
1029          * allocation. Only reason why this is done is because this way the lock
1030          * is held only once, while this doesn't bring the kernel into a
1031          * dangerous state.
1032          */
1033         if (repl->num_counters &&
1034            copy_to_user(repl->counters, counterstmp,
1035            repl->num_counters * sizeof(struct ebt_counter))) {
1036                 /* Silent error, can't fail, new table is already in place */
1037                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1038         }
1039
1040         /* decrease module count and free resources */
1041         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1042                           ebt_cleanup_entry, net, NULL);
1043
1044         vfree(table->entries);
1045         ebt_free_table_info(table);
1046         vfree(table);
1047         vfree(counterstmp);
1048
1049         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1050                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1051         return ret;
1052
1053 free_unlock:
1054         mutex_unlock(&ebt_mutex);
1055 free_iterate:
1056         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1057                           ebt_cleanup_entry, net, NULL);
1058 free_counterstmp:
1059         vfree(counterstmp);
1060         /* can be initialized in translate_table() */
1061         ebt_free_table_info(newinfo);
1062         return ret;
1063 }
1064
1065 /* replace the table */
1066 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1067 {
1068         int ret, countersize;
1069         struct ebt_table_info *newinfo;
1070         struct ebt_replace tmp;
1071
1072         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1073                 return -EFAULT;
1074
1075         if (len != sizeof(tmp) + tmp.entries_size)
1076                 return -EINVAL;
1077
1078         if (tmp.entries_size == 0)
1079                 return -EINVAL;
1080
1081         /* overflow check */
1082         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1083                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1084                 return -ENOMEM;
1085         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1086                 return -ENOMEM;
1087
1088         tmp.name[sizeof(tmp.name) - 1] = 0;
1089
1090         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1091         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1092         if (!newinfo)
1093                 return -ENOMEM;
1094
1095         if (countersize)
1096                 memset(newinfo->counters, 0, countersize);
1097
1098         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1099         if (!newinfo->entries) {
1100                 ret = -ENOMEM;
1101                 goto free_newinfo;
1102         }
1103         if (copy_from_user(
1104            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1105                 ret = -EFAULT;
1106                 goto free_entries;
1107         }
1108
1109         ret = do_replace_finish(net, &tmp, newinfo);
1110         if (ret == 0)
1111                 return ret;
1112 free_entries:
1113         vfree(newinfo->entries);
1114 free_newinfo:
1115         vfree(newinfo);
1116         return ret;
1117 }
1118
1119 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1120 {
1121         mutex_lock(&ebt_mutex);
1122         list_del(&table->list);
1123         mutex_unlock(&ebt_mutex);
1124         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1125                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1126         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1127                           ebt_cleanup_entry, net, NULL);
1128         if (table->private->nentries)
1129                 module_put(table->me);
1130         vfree(table->private->entries);
1131         ebt_free_table_info(table->private);
1132         vfree(table->private);
1133         kfree(table);
1134 }
1135
1136 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1137                        const struct nf_hook_ops *ops, struct ebt_table **res)
1138 {
1139         struct ebt_table_info *newinfo;
1140         struct ebt_table *t, *table;
1141         struct ebt_replace_kernel *repl;
1142         int ret, i, countersize;
1143         void *p;
1144
1145         if (input_table == NULL || (repl = input_table->table) == NULL ||
1146             repl->entries == NULL || repl->entries_size == 0 ||
1147             repl->counters != NULL || input_table->private != NULL)
1148                 return -EINVAL;
1149
1150         /* Don't add one table to multiple lists. */
1151         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1152         if (!table) {
1153                 ret = -ENOMEM;
1154                 goto out;
1155         }
1156
1157         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1158         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1159         ret = -ENOMEM;
1160         if (!newinfo)
1161                 goto free_table;
1162
1163         p = vmalloc(repl->entries_size);
1164         if (!p)
1165                 goto free_newinfo;
1166
1167         memcpy(p, repl->entries, repl->entries_size);
1168         newinfo->entries = p;
1169
1170         newinfo->entries_size = repl->entries_size;
1171         newinfo->nentries = repl->nentries;
1172
1173         if (countersize)
1174                 memset(newinfo->counters, 0, countersize);
1175
1176         /* fill in newinfo and parse the entries */
1177         newinfo->chainstack = NULL;
1178         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1179                 if ((repl->valid_hooks & (1 << i)) == 0)
1180                         newinfo->hook_entry[i] = NULL;
1181                 else
1182                         newinfo->hook_entry[i] = p +
1183                                 ((char *)repl->hook_entry[i] - repl->entries);
1184         }
1185         ret = translate_table(net, repl->name, newinfo);
1186         if (ret != 0)
1187                 goto free_chainstack;
1188
1189         if (table->check && table->check(newinfo, table->valid_hooks)) {
1190                 ret = -EINVAL;
1191                 goto free_chainstack;
1192         }
1193
1194         table->private = newinfo;
1195         rwlock_init(&table->lock);
1196         mutex_lock(&ebt_mutex);
1197         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1198                 if (strcmp(t->name, table->name) == 0) {
1199                         ret = -EEXIST;
1200                         goto free_unlock;
1201                 }
1202         }
1203
1204         /* Hold a reference count if the chains aren't empty */
1205         if (newinfo->nentries && !try_module_get(table->me)) {
1206                 ret = -ENOENT;
1207                 goto free_unlock;
1208         }
1209         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1210         mutex_unlock(&ebt_mutex);
1211
1212         WRITE_ONCE(*res, table);
1213         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1214         if (ret) {
1215                 __ebt_unregister_table(net, table);
1216                 *res = NULL;
1217         }
1218
1219         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1220                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1221         return ret;
1222 free_unlock:
1223         mutex_unlock(&ebt_mutex);
1224 free_chainstack:
1225         ebt_free_table_info(newinfo);
1226         vfree(newinfo->entries);
1227 free_newinfo:
1228         vfree(newinfo);
1229 free_table:
1230         kfree(table);
1231 out:
1232         return ret;
1233 }
1234
1235 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1236                           const struct nf_hook_ops *ops)
1237 {
1238         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1239         __ebt_unregister_table(net, table);
1240 }
1241
1242 /* userspace just supplied us with counters */
1243 static int do_update_counters(struct net *net, const char *name,
1244                               struct ebt_counter __user *counters,
1245                               unsigned int num_counters, unsigned int len)
1246 {
1247         int i, ret;
1248         struct ebt_counter *tmp;
1249         struct ebt_table *t;
1250
1251         if (num_counters == 0)
1252                 return -EINVAL;
1253
1254         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1255         if (!tmp)
1256                 return -ENOMEM;
1257
1258         t = find_table_lock(net, name, &ret, &ebt_mutex);
1259         if (!t)
1260                 goto free_tmp;
1261
1262         if (num_counters != t->private->nentries) {
1263                 ret = -EINVAL;
1264                 goto unlock_mutex;
1265         }
1266
1267         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1268                 ret = -EFAULT;
1269                 goto unlock_mutex;
1270         }
1271
1272         /* we want an atomic add of the counters */
1273         write_lock_bh(&t->lock);
1274
1275         /* we add to the counters of the first cpu */
1276         for (i = 0; i < num_counters; i++)
1277                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1278
1279         write_unlock_bh(&t->lock);
1280         ret = 0;
1281 unlock_mutex:
1282         mutex_unlock(&ebt_mutex);
1283 free_tmp:
1284         vfree(tmp);
1285         return ret;
1286 }
1287
1288 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1289 {
1290         struct ebt_replace hlp;
1291
1292         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1293                 return -EFAULT;
1294
1295         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1296                 return -EINVAL;
1297
1298         return do_update_counters(net, hlp.name, hlp.counters,
1299                                   hlp.num_counters, len);
1300 }
1301
1302 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1303                                   const char *data, int entrysize,
1304                                   int usersize, int datasize, u8 revision)
1305 {
1306         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1307
1308         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1309          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1310          */
1311         strlcpy(name, _name, sizeof(name));
1312         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1313             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1314             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1315             xt_data_to_user(um + entrysize, data, usersize, datasize,
1316                             XT_ALIGN(datasize)))
1317                 return -EFAULT;
1318
1319         return 0;
1320 }
1321
1322 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1323                                     const char *base, char __user *ubase)
1324 {
1325         return ebt_obj_to_user(ubase + ((char *)m - base),
1326                                m->u.match->name, m->data, sizeof(*m),
1327                                m->u.match->usersize, m->match_size,
1328                                m->u.match->revision);
1329 }
1330
1331 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1332                                       const char *base, char __user *ubase)
1333 {
1334         return ebt_obj_to_user(ubase + ((char *)w - base),
1335                                w->u.watcher->name, w->data, sizeof(*w),
1336                                w->u.watcher->usersize, w->watcher_size,
1337                                w->u.watcher->revision);
1338 }
1339
1340 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1341                                     char __user *ubase)
1342 {
1343         int ret;
1344         char __user *hlp;
1345         const struct ebt_entry_target *t;
1346
1347         if (e->bitmask == 0) {
1348                 /* special case !EBT_ENTRY_OR_ENTRIES */
1349                 if (copy_to_user(ubase + ((char *)e - base), e,
1350                                  sizeof(struct ebt_entries)))
1351                         return -EFAULT;
1352                 return 0;
1353         }
1354
1355         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1356                 return -EFAULT;
1357
1358         hlp = ubase + (((char *)e + e->target_offset) - base);
1359         t = ebt_get_target_c(e);
1360
1361         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1362         if (ret != 0)
1363                 return ret;
1364         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1365         if (ret != 0)
1366                 return ret;
1367         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1368                               t->u.target->usersize, t->target_size,
1369                               t->u.target->revision);
1370         if (ret != 0)
1371                 return ret;
1372
1373         return 0;
1374 }
1375
1376 static int copy_counters_to_user(struct ebt_table *t,
1377                                  const struct ebt_counter *oldcounters,
1378                                  void __user *user, unsigned int num_counters,
1379                                  unsigned int nentries)
1380 {
1381         struct ebt_counter *counterstmp;
1382         int ret = 0;
1383
1384         /* userspace might not need the counters */
1385         if (num_counters == 0)
1386                 return 0;
1387
1388         if (num_counters != nentries)
1389                 return -EINVAL;
1390
1391         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1392         if (!counterstmp)
1393                 return -ENOMEM;
1394
1395         write_lock_bh(&t->lock);
1396         get_counters(oldcounters, counterstmp, nentries);
1397         write_unlock_bh(&t->lock);
1398
1399         if (copy_to_user(user, counterstmp,
1400            nentries * sizeof(struct ebt_counter)))
1401                 ret = -EFAULT;
1402         vfree(counterstmp);
1403         return ret;
1404 }
1405
1406 /* called with ebt_mutex locked */
1407 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1408                                    const int *len, int cmd)
1409 {
1410         struct ebt_replace tmp;
1411         const struct ebt_counter *oldcounters;
1412         unsigned int entries_size, nentries;
1413         int ret;
1414         char *entries;
1415
1416         if (cmd == EBT_SO_GET_ENTRIES) {
1417                 entries_size = t->private->entries_size;
1418                 nentries = t->private->nentries;
1419                 entries = t->private->entries;
1420                 oldcounters = t->private->counters;
1421         } else {
1422                 entries_size = t->table->entries_size;
1423                 nentries = t->table->nentries;
1424                 entries = t->table->entries;
1425                 oldcounters = t->table->counters;
1426         }
1427
1428         if (copy_from_user(&tmp, user, sizeof(tmp)))
1429                 return -EFAULT;
1430
1431         if (*len != sizeof(struct ebt_replace) + entries_size +
1432            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1433                 return -EINVAL;
1434
1435         if (tmp.nentries != nentries)
1436                 return -EINVAL;
1437
1438         if (tmp.entries_size != entries_size)
1439                 return -EINVAL;
1440
1441         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1442                                         tmp.num_counters, nentries);
1443         if (ret)
1444                 return ret;
1445
1446         /* set the match/watcher/target names right */
1447         return EBT_ENTRY_ITERATE(entries, entries_size,
1448            ebt_entry_to_user, entries, tmp.entries);
1449 }
1450
1451 #ifdef CONFIG_COMPAT
1452 /* 32 bit-userspace compatibility definitions. */
1453 struct compat_ebt_replace {
1454         char name[EBT_TABLE_MAXNAMELEN];
1455         compat_uint_t valid_hooks;
1456         compat_uint_t nentries;
1457         compat_uint_t entries_size;
1458         /* start of the chains */
1459         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1460         /* nr of counters userspace expects back */
1461         compat_uint_t num_counters;
1462         /* where the kernel will put the old counters. */
1463         compat_uptr_t counters;
1464         compat_uptr_t entries;
1465 };
1466
1467 /* struct ebt_entry_match, _target and _watcher have same layout */
1468 struct compat_ebt_entry_mwt {
1469         union {
1470                 struct {
1471                         char name[EBT_EXTENSION_MAXNAMELEN];
1472                         u8 revision;
1473                 };
1474                 compat_uptr_t ptr;
1475         } u;
1476         compat_uint_t match_size;
1477         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1478 };
1479
1480 /* account for possible padding between match_size and ->data */
1481 static int ebt_compat_entry_padsize(void)
1482 {
1483         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1484                         sizeof(struct compat_ebt_entry_mwt));
1485         return (int) sizeof(struct ebt_entry_match) -
1486                         sizeof(struct compat_ebt_entry_mwt);
1487 }
1488
1489 static int ebt_compat_match_offset(const struct xt_match *match,
1490                                    unsigned int userlen)
1491 {
1492         /* ebt_among needs special handling. The kernel .matchsize is
1493          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1494          * value is expected.
1495          * Example: userspace sends 4500, ebt_among.c wants 4504.
1496          */
1497         if (unlikely(match->matchsize == -1))
1498                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1499         return xt_compat_match_offset(match);
1500 }
1501
1502 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1503                                 unsigned int *size)
1504 {
1505         const struct xt_match *match = m->u.match;
1506         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1507         int off = ebt_compat_match_offset(match, m->match_size);
1508         compat_uint_t msize = m->match_size - off;
1509
1510         if (WARN_ON(off >= m->match_size))
1511                 return -EINVAL;
1512
1513         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1514             put_user(match->revision, &cm->u.revision) ||
1515             put_user(msize, &cm->match_size))
1516                 return -EFAULT;
1517
1518         if (match->compat_to_user) {
1519                 if (match->compat_to_user(cm->data, m->data))
1520                         return -EFAULT;
1521         } else {
1522                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1523                                     COMPAT_XT_ALIGN(msize)))
1524                         return -EFAULT;
1525         }
1526
1527         *size -= ebt_compat_entry_padsize() + off;
1528         *dstptr = cm->data;
1529         *dstptr += msize;
1530         return 0;
1531 }
1532
1533 static int compat_target_to_user(struct ebt_entry_target *t,
1534                                  void __user **dstptr,
1535                                  unsigned int *size)
1536 {
1537         const struct xt_target *target = t->u.target;
1538         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1539         int off = xt_compat_target_offset(target);
1540         compat_uint_t tsize = t->target_size - off;
1541
1542         if (WARN_ON(off >= t->target_size))
1543                 return -EINVAL;
1544
1545         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1546             put_user(target->revision, &cm->u.revision) ||
1547             put_user(tsize, &cm->match_size))
1548                 return -EFAULT;
1549
1550         if (target->compat_to_user) {
1551                 if (target->compat_to_user(cm->data, t->data))
1552                         return -EFAULT;
1553         } else {
1554                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1555                                     COMPAT_XT_ALIGN(tsize)))
1556                         return -EFAULT;
1557         }
1558
1559         *size -= ebt_compat_entry_padsize() + off;
1560         *dstptr = cm->data;
1561         *dstptr += tsize;
1562         return 0;
1563 }
1564
1565 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1566                                   void __user **dstptr,
1567                                   unsigned int *size)
1568 {
1569         return compat_target_to_user((struct ebt_entry_target *)w,
1570                                                         dstptr, size);
1571 }
1572
1573 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1574                                 unsigned int *size)
1575 {
1576         struct ebt_entry_target *t;
1577         struct ebt_entry __user *ce;
1578         u32 watchers_offset, target_offset, next_offset;
1579         compat_uint_t origsize;
1580         int ret;
1581
1582         if (e->bitmask == 0) {
1583                 if (*size < sizeof(struct ebt_entries))
1584                         return -EINVAL;
1585                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1586                         return -EFAULT;
1587
1588                 *dstptr += sizeof(struct ebt_entries);
1589                 *size -= sizeof(struct ebt_entries);
1590                 return 0;
1591         }
1592
1593         if (*size < sizeof(*ce))
1594                 return -EINVAL;
1595
1596         ce = *dstptr;
1597         if (copy_to_user(ce, e, sizeof(*ce)))
1598                 return -EFAULT;
1599
1600         origsize = *size;
1601         *dstptr += sizeof(*ce);
1602
1603         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1604         if (ret)
1605                 return ret;
1606         watchers_offset = e->watchers_offset - (origsize - *size);
1607
1608         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1609         if (ret)
1610                 return ret;
1611         target_offset = e->target_offset - (origsize - *size);
1612
1613         t = ebt_get_target(e);
1614
1615         ret = compat_target_to_user(t, dstptr, size);
1616         if (ret)
1617                 return ret;
1618         next_offset = e->next_offset - (origsize - *size);
1619
1620         if (put_user(watchers_offset, &ce->watchers_offset) ||
1621             put_user(target_offset, &ce->target_offset) ||
1622             put_user(next_offset, &ce->next_offset))
1623                 return -EFAULT;
1624
1625         *size -= sizeof(*ce);
1626         return 0;
1627 }
1628
1629 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1630 {
1631         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1632         *off += ebt_compat_entry_padsize();
1633         return 0;
1634 }
1635
1636 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1637 {
1638         *off += xt_compat_target_offset(w->u.watcher);
1639         *off += ebt_compat_entry_padsize();
1640         return 0;
1641 }
1642
1643 static int compat_calc_entry(const struct ebt_entry *e,
1644                              const struct ebt_table_info *info,
1645                              const void *base,
1646                              struct compat_ebt_replace *newinfo)
1647 {
1648         const struct ebt_entry_target *t;
1649         unsigned int entry_offset;
1650         int off, ret, i;
1651
1652         if (e->bitmask == 0)
1653                 return 0;
1654
1655         off = 0;
1656         entry_offset = (void *)e - base;
1657
1658         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1659         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1660
1661         t = ebt_get_target_c(e);
1662
1663         off += xt_compat_target_offset(t->u.target);
1664         off += ebt_compat_entry_padsize();
1665
1666         newinfo->entries_size -= off;
1667
1668         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1669         if (ret)
1670                 return ret;
1671
1672         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1673                 const void *hookptr = info->hook_entry[i];
1674                 if (info->hook_entry[i] &&
1675                     (e < (struct ebt_entry *)(base - hookptr))) {
1676                         newinfo->hook_entry[i] -= off;
1677                         pr_debug("0x%08X -> 0x%08X\n",
1678                                         newinfo->hook_entry[i] + off,
1679                                         newinfo->hook_entry[i]);
1680                 }
1681         }
1682
1683         return 0;
1684 }
1685
1686 static int ebt_compat_init_offsets(unsigned int number)
1687 {
1688         if (number > INT_MAX)
1689                 return -EINVAL;
1690
1691         /* also count the base chain policies */
1692         number += NF_BR_NUMHOOKS;
1693
1694         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1695 }
1696
1697 static int compat_table_info(const struct ebt_table_info *info,
1698                              struct compat_ebt_replace *newinfo)
1699 {
1700         unsigned int size = info->entries_size;
1701         const void *entries = info->entries;
1702         int ret;
1703
1704         newinfo->entries_size = size;
1705         ret = ebt_compat_init_offsets(info->nentries);
1706         if (ret)
1707                 return ret;
1708
1709         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1710                                                         entries, newinfo);
1711 }
1712
1713 static int compat_copy_everything_to_user(struct ebt_table *t,
1714                                           void __user *user, int *len, int cmd)
1715 {
1716         struct compat_ebt_replace repl, tmp;
1717         struct ebt_counter *oldcounters;
1718         struct ebt_table_info tinfo;
1719         int ret;
1720         void __user *pos;
1721
1722         memset(&tinfo, 0, sizeof(tinfo));
1723
1724         if (cmd == EBT_SO_GET_ENTRIES) {
1725                 tinfo.entries_size = t->private->entries_size;
1726                 tinfo.nentries = t->private->nentries;
1727                 tinfo.entries = t->private->entries;
1728                 oldcounters = t->private->counters;
1729         } else {
1730                 tinfo.entries_size = t->table->entries_size;
1731                 tinfo.nentries = t->table->nentries;
1732                 tinfo.entries = t->table->entries;
1733                 oldcounters = t->table->counters;
1734         }
1735
1736         if (copy_from_user(&tmp, user, sizeof(tmp)))
1737                 return -EFAULT;
1738
1739         if (tmp.nentries != tinfo.nentries ||
1740            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1741                 return -EINVAL;
1742
1743         memcpy(&repl, &tmp, sizeof(repl));
1744         if (cmd == EBT_SO_GET_ENTRIES)
1745                 ret = compat_table_info(t->private, &repl);
1746         else
1747                 ret = compat_table_info(&tinfo, &repl);
1748         if (ret)
1749                 return ret;
1750
1751         if (*len != sizeof(tmp) + repl.entries_size +
1752            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1753                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1754                                 *len, tinfo.entries_size, repl.entries_size);
1755                 return -EINVAL;
1756         }
1757
1758         /* userspace might not need the counters */
1759         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1760                                         tmp.num_counters, tinfo.nentries);
1761         if (ret)
1762                 return ret;
1763
1764         pos = compat_ptr(tmp.entries);
1765         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1766                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1767 }
1768
1769 struct ebt_entries_buf_state {
1770         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1771         u32 buf_kern_len;       /* total size of kernel buffer */
1772         u32 buf_kern_offset;    /* amount of data copied so far */
1773         u32 buf_user_offset;    /* read position in userspace buffer */
1774 };
1775
1776 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1777 {
1778         state->buf_kern_offset += sz;
1779         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1780 }
1781
1782 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1783                        const void *data, unsigned int sz)
1784 {
1785         if (state->buf_kern_start == NULL)
1786                 goto count_only;
1787
1788         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1789                 return -EINVAL;
1790
1791         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1792
1793  count_only:
1794         state->buf_user_offset += sz;
1795         return ebt_buf_count(state, sz);
1796 }
1797
1798 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1799 {
1800         char *b = state->buf_kern_start;
1801
1802         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1803                 return -EINVAL;
1804
1805         if (b != NULL && sz > 0)
1806                 memset(b + state->buf_kern_offset, 0, sz);
1807         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1808         return ebt_buf_count(state, sz);
1809 }
1810
1811 enum compat_mwt {
1812         EBT_COMPAT_MATCH,
1813         EBT_COMPAT_WATCHER,
1814         EBT_COMPAT_TARGET,
1815 };
1816
1817 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1818                                 enum compat_mwt compat_mwt,
1819                                 struct ebt_entries_buf_state *state,
1820                                 const unsigned char *base)
1821 {
1822         char name[EBT_EXTENSION_MAXNAMELEN];
1823         struct xt_match *match;
1824         struct xt_target *wt;
1825         void *dst = NULL;
1826         int off, pad = 0;
1827         unsigned int size_kern, match_size = mwt->match_size;
1828
1829         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1830                 return -EINVAL;
1831
1832         if (state->buf_kern_start)
1833                 dst = state->buf_kern_start + state->buf_kern_offset;
1834
1835         switch (compat_mwt) {
1836         case EBT_COMPAT_MATCH:
1837                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1838                                               mwt->u.revision);
1839                 if (IS_ERR(match))
1840                         return PTR_ERR(match);
1841
1842                 off = ebt_compat_match_offset(match, match_size);
1843                 if (dst) {
1844                         if (match->compat_from_user)
1845                                 match->compat_from_user(dst, mwt->data);
1846                         else
1847                                 memcpy(dst, mwt->data, match_size);
1848                 }
1849
1850                 size_kern = match->matchsize;
1851                 if (unlikely(size_kern == -1))
1852                         size_kern = match_size;
1853                 module_put(match->me);
1854                 break;
1855         case EBT_COMPAT_WATCHER:
1856         case EBT_COMPAT_TARGET:
1857                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1858                                             mwt->u.revision);
1859                 if (IS_ERR(wt))
1860                         return PTR_ERR(wt);
1861                 off = xt_compat_target_offset(wt);
1862
1863                 if (dst) {
1864                         if (wt->compat_from_user)
1865                                 wt->compat_from_user(dst, mwt->data);
1866                         else
1867                                 memcpy(dst, mwt->data, match_size);
1868                 }
1869
1870                 size_kern = wt->targetsize;
1871                 module_put(wt->me);
1872                 break;
1873
1874         default:
1875                 return -EINVAL;
1876         }
1877
1878         state->buf_kern_offset += match_size + off;
1879         state->buf_user_offset += match_size;
1880         pad = XT_ALIGN(size_kern) - size_kern;
1881
1882         if (pad > 0 && dst) {
1883                 if (WARN_ON(state->buf_kern_len <= pad))
1884                         return -EINVAL;
1885                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
1886                         return -EINVAL;
1887                 memset(dst + size_kern, 0, pad);
1888         }
1889         return off + match_size;
1890 }
1891
1892 /* return size of all matches, watchers or target, including necessary
1893  * alignment and padding.
1894  */
1895 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
1896                         unsigned int size_left, enum compat_mwt type,
1897                         struct ebt_entries_buf_state *state, const void *base)
1898 {
1899         const char *buf = (const char *)match32;
1900         int growth = 0;
1901
1902         if (size_left == 0)
1903                 return 0;
1904
1905         do {
1906                 struct ebt_entry_match *match_kern;
1907                 int ret;
1908
1909                 if (size_left < sizeof(*match32))
1910                         return -EINVAL;
1911
1912                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1913                 if (match_kern) {
1914                         char *tmp;
1915                         tmp = state->buf_kern_start + state->buf_kern_offset;
1916                         match_kern = (struct ebt_entry_match *) tmp;
1917                 }
1918                 ret = ebt_buf_add(state, buf, sizeof(*match32));
1919                 if (ret < 0)
1920                         return ret;
1921                 size_left -= sizeof(*match32);
1922
1923                 /* add padding before match->data (if any) */
1924                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1925                 if (ret < 0)
1926                         return ret;
1927
1928                 if (match32->match_size > size_left)
1929                         return -EINVAL;
1930
1931                 size_left -= match32->match_size;
1932
1933                 ret = compat_mtw_from_user(match32, type, state, base);
1934                 if (ret < 0)
1935                         return ret;
1936
1937                 if (WARN_ON(ret < match32->match_size))
1938                         return -EINVAL;
1939                 growth += ret - match32->match_size;
1940                 growth += ebt_compat_entry_padsize();
1941
1942                 buf += sizeof(*match32);
1943                 buf += match32->match_size;
1944
1945                 if (match_kern)
1946                         match_kern->match_size = ret;
1947
1948                 match32 = (struct compat_ebt_entry_mwt *) buf;
1949         } while (size_left);
1950
1951         return growth;
1952 }
1953
1954 /* called for all ebt_entry structures. */
1955 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
1956                           unsigned int *total,
1957                           struct ebt_entries_buf_state *state)
1958 {
1959         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
1960         /* stores match/watchers/targets & offset of next struct ebt_entry: */
1961         unsigned int offsets[4];
1962         unsigned int *offsets_update = NULL;
1963         int ret;
1964         char *buf_start;
1965
1966         if (*total < sizeof(struct ebt_entries))
1967                 return -EINVAL;
1968
1969         if (!entry->bitmask) {
1970                 *total -= sizeof(struct ebt_entries);
1971                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
1972         }
1973         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
1974                 return -EINVAL;
1975
1976         startoff = state->buf_user_offset;
1977         /* pull in most part of ebt_entry, it does not need to be changed. */
1978         ret = ebt_buf_add(state, entry,
1979                         offsetof(struct ebt_entry, watchers_offset));
1980         if (ret < 0)
1981                 return ret;
1982
1983         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
1984         memcpy(&offsets[1], &entry->watchers_offset,
1985                         sizeof(offsets) - sizeof(offsets[0]));
1986
1987         if (state->buf_kern_start) {
1988                 buf_start = state->buf_kern_start + state->buf_kern_offset;
1989                 offsets_update = (unsigned int *) buf_start;
1990         }
1991         ret = ebt_buf_add(state, &offsets[1],
1992                         sizeof(offsets) - sizeof(offsets[0]));
1993         if (ret < 0)
1994                 return ret;
1995         buf_start = (char *) entry;
1996         /* 0: matches offset, always follows ebt_entry.
1997          * 1: watchers offset, from ebt_entry structure
1998          * 2: target offset, from ebt_entry structure
1999          * 3: next ebt_entry offset, from ebt_entry structure
2000          *
2001          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2002          */
2003         for (i = 0; i < 4 ; ++i) {
2004                 if (offsets[i] > *total)
2005                         return -EINVAL;
2006
2007                 if (i < 3 && offsets[i] == *total)
2008                         return -EINVAL;
2009
2010                 if (i == 0)
2011                         continue;
2012                 if (offsets[i-1] > offsets[i])
2013                         return -EINVAL;
2014         }
2015
2016         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2017                 struct compat_ebt_entry_mwt *match32;
2018                 unsigned int size;
2019                 char *buf = buf_start + offsets[i];
2020
2021                 if (offsets[i] > offsets[j])
2022                         return -EINVAL;
2023
2024                 match32 = (struct compat_ebt_entry_mwt *) buf;
2025                 size = offsets[j] - offsets[i];
2026                 ret = ebt_size_mwt(match32, size, i, state, base);
2027                 if (ret < 0)
2028                         return ret;
2029                 new_offset += ret;
2030                 if (offsets_update && new_offset) {
2031                         pr_debug("change offset %d to %d\n",
2032                                 offsets_update[i], offsets[j] + new_offset);
2033                         offsets_update[i] = offsets[j] + new_offset;
2034                 }
2035         }
2036
2037         if (state->buf_kern_start == NULL) {
2038                 unsigned int offset = buf_start - (char *) base;
2039
2040                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2041                 if (ret < 0)
2042                         return ret;
2043         }
2044
2045         next_expected_off = state->buf_user_offset - startoff;
2046         if (next_expected_off != entry->next_offset)
2047                 return -EINVAL;
2048
2049         if (*total < entry->next_offset)
2050                 return -EINVAL;
2051         *total -= entry->next_offset;
2052         return 0;
2053 }
2054
2055 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2056  * It might need more memory when copied to a 64 bit kernel in case
2057  * userspace is 32-bit. So, first task: find out how much memory is needed.
2058  *
2059  * Called before validation is performed.
2060  */
2061 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2062                                 struct ebt_entries_buf_state *state)
2063 {
2064         unsigned int size_remaining = size_user;
2065         int ret;
2066
2067         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2068                                         &size_remaining, state);
2069         if (ret < 0)
2070                 return ret;
2071
2072         if (size_remaining)
2073                 return -EINVAL;
2074
2075         return state->buf_kern_offset;
2076 }
2077
2078
2079 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2080                                              sockptr_t arg, unsigned int len)
2081 {
2082         struct compat_ebt_replace tmp;
2083         int i;
2084
2085         if (len < sizeof(tmp))
2086                 return -EINVAL;
2087
2088         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2089                 return -EFAULT;
2090
2091         if (len != sizeof(tmp) + tmp.entries_size)
2092                 return -EINVAL;
2093
2094         if (tmp.entries_size == 0)
2095                 return -EINVAL;
2096
2097         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2098                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2099                 return -ENOMEM;
2100         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2101                 return -ENOMEM;
2102
2103         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2104
2105         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2106         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2107                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2108
2109         repl->num_counters = tmp.num_counters;
2110         repl->counters = compat_ptr(tmp.counters);
2111         repl->entries = compat_ptr(tmp.entries);
2112         return 0;
2113 }
2114
2115 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2116 {
2117         int ret, i, countersize, size64;
2118         struct ebt_table_info *newinfo;
2119         struct ebt_replace tmp;
2120         struct ebt_entries_buf_state state;
2121         void *entries_tmp;
2122
2123         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2124         if (ret) {
2125                 /* try real handler in case userland supplied needed padding */
2126                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2127                         ret = 0;
2128                 return ret;
2129         }
2130
2131         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2132         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2133         if (!newinfo)
2134                 return -ENOMEM;
2135
2136         if (countersize)
2137                 memset(newinfo->counters, 0, countersize);
2138
2139         memset(&state, 0, sizeof(state));
2140
2141         newinfo->entries = vmalloc(tmp.entries_size);
2142         if (!newinfo->entries) {
2143                 ret = -ENOMEM;
2144                 goto free_newinfo;
2145         }
2146         if (copy_from_user(
2147            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2148                 ret = -EFAULT;
2149                 goto free_entries;
2150         }
2151
2152         entries_tmp = newinfo->entries;
2153
2154         xt_compat_lock(NFPROTO_BRIDGE);
2155
2156         ret = ebt_compat_init_offsets(tmp.nentries);
2157         if (ret < 0)
2158                 goto out_unlock;
2159
2160         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2161         if (ret < 0)
2162                 goto out_unlock;
2163
2164         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2165                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2166                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2167
2168         size64 = ret;
2169         newinfo->entries = vmalloc(size64);
2170         if (!newinfo->entries) {
2171                 vfree(entries_tmp);
2172                 ret = -ENOMEM;
2173                 goto out_unlock;
2174         }
2175
2176         memset(&state, 0, sizeof(state));
2177         state.buf_kern_start = newinfo->entries;
2178         state.buf_kern_len = size64;
2179
2180         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2181         if (WARN_ON(ret < 0)) {
2182                 vfree(entries_tmp);
2183                 goto out_unlock;
2184         }
2185
2186         vfree(entries_tmp);
2187         tmp.entries_size = size64;
2188
2189         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2190                 char __user *usrptr;
2191                 if (tmp.hook_entry[i]) {
2192                         unsigned int delta;
2193                         usrptr = (char __user *) tmp.hook_entry[i];
2194                         delta = usrptr - tmp.entries;
2195                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2196                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2197                 }
2198         }
2199
2200         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2201         xt_compat_unlock(NFPROTO_BRIDGE);
2202
2203         ret = do_replace_finish(net, &tmp, newinfo);
2204         if (ret == 0)
2205                 return ret;
2206 free_entries:
2207         vfree(newinfo->entries);
2208 free_newinfo:
2209         vfree(newinfo);
2210         return ret;
2211 out_unlock:
2212         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2213         xt_compat_unlock(NFPROTO_BRIDGE);
2214         goto free_entries;
2215 }
2216
2217 static int compat_update_counters(struct net *net, sockptr_t arg,
2218                                   unsigned int len)
2219 {
2220         struct compat_ebt_replace hlp;
2221
2222         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2223                 return -EFAULT;
2224
2225         /* try real handler in case userland supplied needed padding */
2226         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2227                 return update_counters(net, arg, len);
2228
2229         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2230                                   hlp.num_counters, len);
2231 }
2232
2233 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2234                 void __user *user, int *len)
2235 {
2236         int ret;
2237         struct compat_ebt_replace tmp;
2238         struct ebt_table *t;
2239         struct net *net = sock_net(sk);
2240
2241         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2242             *len != sizeof(struct compat_ebt_replace))
2243                 return -EINVAL;
2244
2245         if (copy_from_user(&tmp, user, sizeof(tmp)))
2246                 return -EFAULT;
2247
2248         tmp.name[sizeof(tmp.name) - 1] = '\0';
2249
2250         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2251         if (!t)
2252                 return ret;
2253
2254         xt_compat_lock(NFPROTO_BRIDGE);
2255         switch (cmd) {
2256         case EBT_SO_GET_INFO:
2257                 tmp.nentries = t->private->nentries;
2258                 ret = compat_table_info(t->private, &tmp);
2259                 if (ret)
2260                         goto out;
2261                 tmp.valid_hooks = t->valid_hooks;
2262
2263                 if (copy_to_user(user, &tmp, *len) != 0) {
2264                         ret = -EFAULT;
2265                         break;
2266                 }
2267                 ret = 0;
2268                 break;
2269         case EBT_SO_GET_INIT_INFO:
2270                 tmp.nentries = t->table->nentries;
2271                 tmp.entries_size = t->table->entries_size;
2272                 tmp.valid_hooks = t->table->valid_hooks;
2273
2274                 if (copy_to_user(user, &tmp, *len) != 0) {
2275                         ret = -EFAULT;
2276                         break;
2277                 }
2278                 ret = 0;
2279                 break;
2280         case EBT_SO_GET_ENTRIES:
2281         case EBT_SO_GET_INIT_ENTRIES:
2282                 /* try real handler first in case of userland-side padding.
2283                  * in case we are dealing with an 'ordinary' 32 bit binary
2284                  * without 64bit compatibility padding, this will fail right
2285                  * after copy_from_user when the *len argument is validated.
2286                  *
2287                  * the compat_ variant needs to do one pass over the kernel
2288                  * data set to adjust for size differences before it the check.
2289                  */
2290                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2291                         ret = 0;
2292                 else
2293                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2294                 break;
2295         default:
2296                 ret = -EINVAL;
2297         }
2298  out:
2299         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2300         xt_compat_unlock(NFPROTO_BRIDGE);
2301         mutex_unlock(&ebt_mutex);
2302         return ret;
2303 }
2304 #endif
2305
2306 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2307 {
2308         struct net *net = sock_net(sk);
2309         struct ebt_replace tmp;
2310         struct ebt_table *t;
2311         int ret;
2312
2313         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2314                 return -EPERM;
2315
2316 #ifdef CONFIG_COMPAT
2317         /* try real handler in case userland supplied needed padding */
2318         if (in_compat_syscall() &&
2319             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2320              *len != sizeof(tmp)))
2321                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2322 #endif
2323
2324         if (copy_from_user(&tmp, user, sizeof(tmp)))
2325                 return -EFAULT;
2326
2327         tmp.name[sizeof(tmp.name) - 1] = '\0';
2328
2329         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2330         if (!t)
2331                 return ret;
2332
2333         switch (cmd) {
2334         case EBT_SO_GET_INFO:
2335         case EBT_SO_GET_INIT_INFO:
2336                 if (*len != sizeof(struct ebt_replace)) {
2337                         ret = -EINVAL;
2338                         mutex_unlock(&ebt_mutex);
2339                         break;
2340                 }
2341                 if (cmd == EBT_SO_GET_INFO) {
2342                         tmp.nentries = t->private->nentries;
2343                         tmp.entries_size = t->private->entries_size;
2344                         tmp.valid_hooks = t->valid_hooks;
2345                 } else {
2346                         tmp.nentries = t->table->nentries;
2347                         tmp.entries_size = t->table->entries_size;
2348                         tmp.valid_hooks = t->table->valid_hooks;
2349                 }
2350                 mutex_unlock(&ebt_mutex);
2351                 if (copy_to_user(user, &tmp, *len) != 0) {
2352                         ret = -EFAULT;
2353                         break;
2354                 }
2355                 ret = 0;
2356                 break;
2357
2358         case EBT_SO_GET_ENTRIES:
2359         case EBT_SO_GET_INIT_ENTRIES:
2360                 ret = copy_everything_to_user(t, user, len, cmd);
2361                 mutex_unlock(&ebt_mutex);
2362                 break;
2363
2364         default:
2365                 mutex_unlock(&ebt_mutex);
2366                 ret = -EINVAL;
2367         }
2368
2369         return ret;
2370 }
2371
2372 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2373                 unsigned int len)
2374 {
2375         struct net *net = sock_net(sk);
2376         int ret;
2377
2378         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2379                 return -EPERM;
2380
2381         switch (cmd) {
2382         case EBT_SO_SET_ENTRIES:
2383 #ifdef CONFIG_COMPAT
2384                 if (in_compat_syscall())
2385                         ret = compat_do_replace(net, arg, len);
2386                 else
2387 #endif
2388                         ret = do_replace(net, arg, len);
2389                 break;
2390         case EBT_SO_SET_COUNTERS:
2391 #ifdef CONFIG_COMPAT
2392                 if (in_compat_syscall())
2393                         ret = compat_update_counters(net, arg, len);
2394                 else
2395 #endif
2396                         ret = update_counters(net, arg, len);
2397                 break;
2398         default:
2399                 ret = -EINVAL;
2400         }
2401         return ret;
2402 }
2403
2404 static struct nf_sockopt_ops ebt_sockopts = {
2405         .pf             = PF_INET,
2406         .set_optmin     = EBT_BASE_CTL,
2407         .set_optmax     = EBT_SO_SET_MAX + 1,
2408         .set            = do_ebt_set_ctl,
2409         .get_optmin     = EBT_BASE_CTL,
2410         .get_optmax     = EBT_SO_GET_MAX + 1,
2411         .get            = do_ebt_get_ctl,
2412         .owner          = THIS_MODULE,
2413 };
2414
2415 static int __init ebtables_init(void)
2416 {
2417         int ret;
2418
2419         ret = xt_register_target(&ebt_standard_target);
2420         if (ret < 0)
2421                 return ret;
2422         ret = nf_register_sockopt(&ebt_sockopts);
2423         if (ret < 0) {
2424                 xt_unregister_target(&ebt_standard_target);
2425                 return ret;
2426         }
2427
2428         return 0;
2429 }
2430
2431 static void __exit ebtables_fini(void)
2432 {
2433         nf_unregister_sockopt(&ebt_sockopts);
2434         xt_unregister_target(&ebt_standard_target);
2435 }
2436
2437 EXPORT_SYMBOL(ebt_register_table);
2438 EXPORT_SYMBOL(ebt_unregister_table);
2439 EXPORT_SYMBOL(ebt_do_table);
2440 module_init(ebtables_init);
2441 module_exit(ebtables_fini);
2442 MODULE_LICENSE("GPL");