net/bridge/netfilter/ebtables.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ebtables
   4  *
   5  *  Author:
   6  *  Bart De Schuymer            <bdschuym@pandora.be>
   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), 1, skb->len);
 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].pcnt,
 963                                     counter_base[i].bcnt);
 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 #ifdef CONFIG_AUDIT
1050         if (audit_enabled) {
1051                 audit_log(audit_context(), GFP_KERNEL,
1052                           AUDIT_NETFILTER_CFG,
1053                           "table=%s family=%u entries=%u",
1054                           repl->name, AF_BRIDGE, repl->nentries);
1055         }
1056 #endif
1057         return ret;
1058
1059 free_unlock:
1060         mutex_unlock(&ebt_mutex);
1061 free_iterate:
1062         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1063                           ebt_cleanup_entry, net, NULL);
1064 free_counterstmp:
1065         vfree(counterstmp);
1066         /* can be initialized in translate_table() */
1067         ebt_free_table_info(newinfo);
1068         return ret;
1069 }
1070
1071 /* replace the table */
1072 static int do_replace(struct net *net, const void __user *user,
1073                       unsigned int len)
1074 {
1075         int ret, countersize;
1076         struct ebt_table_info *newinfo;
1077         struct ebt_replace tmp;
1078
1079         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1080                 return -EFAULT;
1081
1082         if (len != sizeof(tmp) + tmp.entries_size)
1083                 return -EINVAL;
1084
1085         if (tmp.entries_size == 0)
1086                 return -EINVAL;
1087
1088         /* overflow check */
1089         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1090                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1091                 return -ENOMEM;
1092         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1093                 return -ENOMEM;
1094
1095         tmp.name[sizeof(tmp.name) - 1] = 0;
1096
1097         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1098         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT,
1099                             PAGE_KERNEL);
1100         if (!newinfo)
1101                 return -ENOMEM;
1102
1103         if (countersize)
1104                 memset(newinfo->counters, 0, countersize);
1105
1106         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT,
1107                                      PAGE_KERNEL);
1108         if (!newinfo->entries) {
1109                 ret = -ENOMEM;
1110                 goto free_newinfo;
1111         }
1112         if (copy_from_user(
1113            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1114                 ret = -EFAULT;
1115                 goto free_entries;
1116         }
1117
1118         ret = do_replace_finish(net, &tmp, newinfo);
1119         if (ret == 0)
1120                 return ret;
1121 free_entries:
1122         vfree(newinfo->entries);
1123 free_newinfo:
1124         vfree(newinfo);
1125         return ret;
1126 }
1127
1128 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1129 {
1130         mutex_lock(&ebt_mutex);
1131         list_del(&table->list);
1132         mutex_unlock(&ebt_mutex);
1133         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1134                           ebt_cleanup_entry, net, NULL);
1135         if (table->private->nentries)
1136                 module_put(table->me);
1137         vfree(table->private->entries);
1138         ebt_free_table_info(table->private);
1139         vfree(table->private);
1140         kfree(table);
1141 }
1142
1143 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1144                        const struct nf_hook_ops *ops, struct ebt_table **res)
1145 {
1146         struct ebt_table_info *newinfo;
1147         struct ebt_table *t, *table;
1148         struct ebt_replace_kernel *repl;
1149         int ret, i, countersize;
1150         void *p;
1151
1152         if (input_table == NULL || (repl = input_table->table) == NULL ||
1153             repl->entries == NULL || repl->entries_size == 0 ||
1154             repl->counters != NULL || input_table->private != NULL)
1155                 return -EINVAL;
1156
1157         /* Don't add one table to multiple lists. */
1158         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1159         if (!table) {
1160                 ret = -ENOMEM;
1161                 goto out;
1162         }
1163
1164         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1165         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1166         ret = -ENOMEM;
1167         if (!newinfo)
1168                 goto free_table;
1169
1170         p = vmalloc(repl->entries_size);
1171         if (!p)
1172                 goto free_newinfo;
1173
1174         memcpy(p, repl->entries, repl->entries_size);
1175         newinfo->entries = p;
1176
1177         newinfo->entries_size = repl->entries_size;
1178         newinfo->nentries = repl->nentries;
1179
1180         if (countersize)
1181                 memset(newinfo->counters, 0, countersize);
1182
1183         /* fill in newinfo and parse the entries */
1184         newinfo->chainstack = NULL;
1185         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1186                 if ((repl->valid_hooks & (1 << i)) == 0)
1187                         newinfo->hook_entry[i] = NULL;
1188                 else
1189                         newinfo->hook_entry[i] = p +
1190                                 ((char *)repl->hook_entry[i] - repl->entries);
1191         }
1192         ret = translate_table(net, repl->name, newinfo);
1193         if (ret != 0)
1194                 goto free_chainstack;
1195
1196         if (table->check && table->check(newinfo, table->valid_hooks)) {
1197                 ret = -EINVAL;
1198                 goto free_chainstack;
1199         }
1200
1201         table->private = newinfo;
1202         rwlock_init(&table->lock);
1203         mutex_lock(&ebt_mutex);
1204         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1205                 if (strcmp(t->name, table->name) == 0) {
1206                         ret = -EEXIST;
1207                         goto free_unlock;
1208                 }
1209         }
1210
1211         /* Hold a reference count if the chains aren't empty */
1212         if (newinfo->nentries && !try_module_get(table->me)) {
1213                 ret = -ENOENT;
1214                 goto free_unlock;
1215         }
1216         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1217         mutex_unlock(&ebt_mutex);
1218
1219         WRITE_ONCE(*res, table);
1220         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1221         if (ret) {
1222                 __ebt_unregister_table(net, table);
1223                 *res = NULL;
1224         }
1225
1226         return ret;
1227 free_unlock:
1228         mutex_unlock(&ebt_mutex);
1229 free_chainstack:
1230         ebt_free_table_info(newinfo);
1231         vfree(newinfo->entries);
1232 free_newinfo:
1233         vfree(newinfo);
1234 free_table:
1235         kfree(table);
1236 out:
1237         return ret;
1238 }
1239
1240 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1241                           const struct nf_hook_ops *ops)
1242 {
1243         nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1244         __ebt_unregister_table(net, table);
1245 }
1246
1247 /* userspace just supplied us with counters */
1248 static int do_update_counters(struct net *net, const char *name,
1249                                 struct ebt_counter __user *counters,
1250                                 unsigned int num_counters,
1251                                 const void __user *user, unsigned int len)
1252 {
1253         int i, ret;
1254         struct ebt_counter *tmp;
1255         struct ebt_table *t;
1256
1257         if (num_counters == 0)
1258                 return -EINVAL;
1259
1260         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1261         if (!tmp)
1262                 return -ENOMEM;
1263
1264         t = find_table_lock(net, name, &ret, &ebt_mutex);
1265         if (!t)
1266                 goto free_tmp;
1267
1268         if (num_counters != t->private->nentries) {
1269                 ret = -EINVAL;
1270                 goto unlock_mutex;
1271         }
1272
1273         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1274                 ret = -EFAULT;
1275                 goto unlock_mutex;
1276         }
1277
1278         /* we want an atomic add of the counters */
1279         write_lock_bh(&t->lock);
1280
1281         /* we add to the counters of the first cpu */
1282         for (i = 0; i < num_counters; i++)
1283                 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt);
1284
1285         write_unlock_bh(&t->lock);
1286         ret = 0;
1287 unlock_mutex:
1288         mutex_unlock(&ebt_mutex);
1289 free_tmp:
1290         vfree(tmp);
1291         return ret;
1292 }
1293
1294 static int update_counters(struct net *net, const void __user *user,
1295                             unsigned int len)
1296 {
1297         struct ebt_replace hlp;
1298
1299         if (copy_from_user(&hlp, user, sizeof(hlp)))
1300                 return -EFAULT;
1301
1302         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1303                 return -EINVAL;
1304
1305         return do_update_counters(net, hlp.name, hlp.counters,
1306                                 hlp.num_counters, user, len);
1307 }
1308
1309 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1310                                   const char *data, int entrysize,
1311                                   int usersize, int datasize, u8 revision)
1312 {
1313         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1314
1315         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1316          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1317          */
1318         strlcpy(name, _name, sizeof(name));
1319         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1320             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1321             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1322             xt_data_to_user(um + entrysize, data, usersize, datasize,
1323                             XT_ALIGN(datasize)))
1324                 return -EFAULT;
1325
1326         return 0;
1327 }
1328
1329 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1330                                     const char *base, char __user *ubase)
1331 {
1332         return ebt_obj_to_user(ubase + ((char *)m - base),
1333                                m->u.match->name, m->data, sizeof(*m),
1334                                m->u.match->usersize, m->match_size,
1335                                m->u.match->revision);
1336 }
1337
1338 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1339                                       const char *base, char __user *ubase)
1340 {
1341         return ebt_obj_to_user(ubase + ((char *)w - base),
1342                                w->u.watcher->name, w->data, sizeof(*w),
1343                                w->u.watcher->usersize, w->watcher_size,
1344                                w->u.watcher->revision);
1345 }
1346
1347 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1348                                     char __user *ubase)
1349 {
1350         int ret;
1351         char __user *hlp;
1352         const struct ebt_entry_target *t;
1353
1354         if (e->bitmask == 0) {
1355                 /* special case !EBT_ENTRY_OR_ENTRIES */
1356                 if (copy_to_user(ubase + ((char *)e - base), e,
1357                                  sizeof(struct ebt_entries)))
1358                         return -EFAULT;
1359                 return 0;
1360         }
1361
1362         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1363                 return -EFAULT;
1364
1365         hlp = ubase + (((char *)e + e->target_offset) - base);
1366         t = ebt_get_target_c(e);
1367
1368         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1369         if (ret != 0)
1370                 return ret;
1371         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1372         if (ret != 0)
1373                 return ret;
1374         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1375                               t->u.target->usersize, t->target_size,
1376                               t->u.target->revision);
1377         if (ret != 0)
1378                 return ret;
1379
1380         return 0;
1381 }
1382
1383 static int copy_counters_to_user(struct ebt_table *t,
1384                                  const struct ebt_counter *oldcounters,
1385                                  void __user *user, unsigned int num_counters,
1386                                  unsigned int nentries)
1387 {
1388         struct ebt_counter *counterstmp;
1389         int ret = 0;
1390
1391         /* userspace might not need the counters */
1392         if (num_counters == 0)
1393                 return 0;
1394
1395         if (num_counters != nentries)
1396                 return -EINVAL;
1397
1398         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1399         if (!counterstmp)
1400                 return -ENOMEM;
1401
1402         write_lock_bh(&t->lock);
1403         get_counters(oldcounters, counterstmp, nentries);
1404         write_unlock_bh(&t->lock);
1405
1406         if (copy_to_user(user, counterstmp,
1407            nentries * sizeof(struct ebt_counter)))
1408                 ret = -EFAULT;
1409         vfree(counterstmp);
1410         return ret;
1411 }
1412
1413 /* called with ebt_mutex locked */
1414 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1415                                    const int *len, int cmd)
1416 {
1417         struct ebt_replace tmp;
1418         const struct ebt_counter *oldcounters;
1419         unsigned int entries_size, nentries;
1420         int ret;
1421         char *entries;
1422
1423         if (cmd == EBT_SO_GET_ENTRIES) {
1424                 entries_size = t->private->entries_size;
1425                 nentries = t->private->nentries;
1426                 entries = t->private->entries;
1427                 oldcounters = t->private->counters;
1428         } else {
1429                 entries_size = t->table->entries_size;
1430                 nentries = t->table->nentries;
1431                 entries = t->table->entries;
1432                 oldcounters = t->table->counters;
1433         }
1434
1435         if (copy_from_user(&tmp, user, sizeof(tmp)))
1436                 return -EFAULT;
1437
1438         if (*len != sizeof(struct ebt_replace) + entries_size +
1439            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1440                 return -EINVAL;
1441
1442         if (tmp.nentries != nentries)
1443                 return -EINVAL;
1444
1445         if (tmp.entries_size != entries_size)
1446                 return -EINVAL;
1447
1448         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1449                                         tmp.num_counters, nentries);
1450         if (ret)
1451                 return ret;
1452
1453         /* set the match/watcher/target names right */
1454         return EBT_ENTRY_ITERATE(entries, entries_size,
1455            ebt_entry_to_user, entries, tmp.entries);
1456 }
1457
1458 static int do_ebt_set_ctl(struct sock *sk,
1459         int cmd, void __user *user, unsigned int len)
1460 {
1461         int ret;
1462         struct net *net = sock_net(sk);
1463
1464         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1465                 return -EPERM;
1466
1467         switch (cmd) {
1468         case EBT_SO_SET_ENTRIES:
1469                 ret = do_replace(net, user, len);
1470                 break;
1471         case EBT_SO_SET_COUNTERS:
1472                 ret = update_counters(net, user, len);
1473                 break;
1474         default:
1475                 ret = -EINVAL;
1476         }
1477         return ret;
1478 }
1479
1480 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1481 {
1482         int ret;
1483         struct ebt_replace tmp;
1484         struct ebt_table *t;
1485         struct net *net = sock_net(sk);
1486
1487         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1488                 return -EPERM;
1489
1490         if (copy_from_user(&tmp, user, sizeof(tmp)))
1491                 return -EFAULT;
1492
1493         tmp.name[sizeof(tmp.name) - 1] = '\0';
1494
1495         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1496         if (!t)
1497                 return ret;
1498
1499         switch (cmd) {
1500         case EBT_SO_GET_INFO:
1501         case EBT_SO_GET_INIT_INFO:
1502                 if (*len != sizeof(struct ebt_replace)) {
1503                         ret = -EINVAL;
1504                         mutex_unlock(&ebt_mutex);
1505                         break;
1506                 }
1507                 if (cmd == EBT_SO_GET_INFO) {
1508                         tmp.nentries = t->private->nentries;
1509                         tmp.entries_size = t->private->entries_size;
1510                         tmp.valid_hooks = t->valid_hooks;
1511                 } else {
1512                         tmp.nentries = t->table->nentries;
1513                         tmp.entries_size = t->table->entries_size;
1514                         tmp.valid_hooks = t->table->valid_hooks;
1515                 }
1516                 mutex_unlock(&ebt_mutex);
1517                 if (copy_to_user(user, &tmp, *len) != 0) {
1518                         ret = -EFAULT;
1519                         break;
1520                 }
1521                 ret = 0;
1522                 break;
1523
1524         case EBT_SO_GET_ENTRIES:
1525         case EBT_SO_GET_INIT_ENTRIES:
1526                 ret = copy_everything_to_user(t, user, len, cmd);
1527                 mutex_unlock(&ebt_mutex);
1528                 break;
1529
1530         default:
1531                 mutex_unlock(&ebt_mutex);
1532                 ret = -EINVAL;
1533         }
1534
1535         return ret;
1536 }
1537
1538 #ifdef CONFIG_COMPAT
1539 /* 32 bit-userspace compatibility definitions. */
1540 struct compat_ebt_replace {
1541         char name[EBT_TABLE_MAXNAMELEN];
1542         compat_uint_t valid_hooks;
1543         compat_uint_t nentries;
1544         compat_uint_t entries_size;
1545         /* start of the chains */
1546         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1547         /* nr of counters userspace expects back */
1548         compat_uint_t num_counters;
1549         /* where the kernel will put the old counters. */
1550         compat_uptr_t counters;
1551         compat_uptr_t entries;
1552 };
1553
1554 /* struct ebt_entry_match, _target and _watcher have same layout */
1555 struct compat_ebt_entry_mwt {
1556         union {
1557                 struct {
1558                         char name[EBT_EXTENSION_MAXNAMELEN];
1559                         u8 revision;
1560                 };
1561                 compat_uptr_t ptr;
1562         } u;
1563         compat_uint_t match_size;
1564         compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace))));
1565 };
1566
1567 /* account for possible padding between match_size and ->data */
1568 static int ebt_compat_entry_padsize(void)
1569 {
1570         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1571                         sizeof(struct compat_ebt_entry_mwt));
1572         return (int) sizeof(struct ebt_entry_match) -
1573                         sizeof(struct compat_ebt_entry_mwt);
1574 }
1575
1576 static int ebt_compat_match_offset(const struct xt_match *match,
1577                                    unsigned int userlen)
1578 {
1579         /* ebt_among needs special handling. The kernel .matchsize is
1580          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1581          * value is expected.
1582          * Example: userspace sends 4500, ebt_among.c wants 4504.
1583          */
1584         if (unlikely(match->matchsize == -1))
1585                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1586         return xt_compat_match_offset(match);
1587 }
1588
1589 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1590                                 unsigned int *size)
1591 {
1592         const struct xt_match *match = m->u.match;
1593         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1594         int off = ebt_compat_match_offset(match, m->match_size);
1595         compat_uint_t msize = m->match_size - off;
1596
1597         if (WARN_ON(off >= m->match_size))
1598                 return -EINVAL;
1599
1600         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1601             put_user(match->revision, &cm->u.revision) ||
1602             put_user(msize, &cm->match_size))
1603                 return -EFAULT;
1604
1605         if (match->compat_to_user) {
1606                 if (match->compat_to_user(cm->data, m->data))
1607                         return -EFAULT;
1608         } else {
1609                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1610                                     COMPAT_XT_ALIGN(msize)))
1611                         return -EFAULT;
1612         }
1613
1614         *size -= ebt_compat_entry_padsize() + off;
1615         *dstptr = cm->data;
1616         *dstptr += msize;
1617         return 0;
1618 }
1619
1620 static int compat_target_to_user(struct ebt_entry_target *t,
1621                                  void __user **dstptr,
1622                                  unsigned int *size)
1623 {
1624         const struct xt_target *target = t->u.target;
1625         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1626         int off = xt_compat_target_offset(target);
1627         compat_uint_t tsize = t->target_size - off;
1628
1629         if (WARN_ON(off >= t->target_size))
1630                 return -EINVAL;
1631
1632         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1633             put_user(target->revision, &cm->u.revision) ||
1634             put_user(tsize, &cm->match_size))
1635                 return -EFAULT;
1636
1637         if (target->compat_to_user) {
1638                 if (target->compat_to_user(cm->data, t->data))
1639                         return -EFAULT;
1640         } else {
1641                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1642                                     COMPAT_XT_ALIGN(tsize)))
1643                         return -EFAULT;
1644         }
1645
1646         *size -= ebt_compat_entry_padsize() + off;
1647         *dstptr = cm->data;
1648         *dstptr += tsize;
1649         return 0;
1650 }
1651
1652 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1653                                   void __user **dstptr,
1654                                   unsigned int *size)
1655 {
1656         return compat_target_to_user((struct ebt_entry_target *)w,
1657                                                         dstptr, size);
1658 }
1659
1660 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1661                                 unsigned int *size)
1662 {
1663         struct ebt_entry_target *t;
1664         struct ebt_entry __user *ce;
1665         u32 watchers_offset, target_offset, next_offset;
1666         compat_uint_t origsize;
1667         int ret;
1668
1669         if (e->bitmask == 0) {
1670                 if (*size < sizeof(struct ebt_entries))
1671                         return -EINVAL;
1672                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1673                         return -EFAULT;
1674
1675                 *dstptr += sizeof(struct ebt_entries);
1676                 *size -= sizeof(struct ebt_entries);
1677                 return 0;
1678         }
1679
1680         if (*size < sizeof(*ce))
1681                 return -EINVAL;
1682
1683         ce = *dstptr;
1684         if (copy_to_user(ce, e, sizeof(*ce)))
1685                 return -EFAULT;
1686
1687         origsize = *size;
1688         *dstptr += sizeof(*ce);
1689
1690         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1691         if (ret)
1692                 return ret;
1693         watchers_offset = e->watchers_offset - (origsize - *size);
1694
1695         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1696         if (ret)
1697                 return ret;
1698         target_offset = e->target_offset - (origsize - *size);
1699
1700         t = ebt_get_target(e);
1701
1702         ret = compat_target_to_user(t, dstptr, size);
1703         if (ret)
1704                 return ret;
1705         next_offset = e->next_offset - (origsize - *size);
1706
1707         if (put_user(watchers_offset, &ce->watchers_offset) ||
1708             put_user(target_offset, &ce->target_offset) ||
1709             put_user(next_offset, &ce->next_offset))
1710                 return -EFAULT;
1711
1712         *size -= sizeof(*ce);
1713         return 0;
1714 }
1715
1716 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1717 {
1718         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1719         *off += ebt_compat_entry_padsize();
1720         return 0;
1721 }
1722
1723 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1724 {
1725         *off += xt_compat_target_offset(w->u.watcher);
1726         *off += ebt_compat_entry_padsize();
1727         return 0;
1728 }
1729
1730 static int compat_calc_entry(const struct ebt_entry *e,
1731                              const struct ebt_table_info *info,
1732                              const void *base,
1733                              struct compat_ebt_replace *newinfo)
1734 {
1735         const struct ebt_entry_target *t;
1736         unsigned int entry_offset;
1737         int off, ret, i;
1738
1739         if (e->bitmask == 0)
1740                 return 0;
1741
1742         off = 0;
1743         entry_offset = (void *)e - base;
1744
1745         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1746         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1747
1748         t = ebt_get_target_c(e);
1749
1750         off += xt_compat_target_offset(t->u.target);
1751         off += ebt_compat_entry_padsize();
1752
1753         newinfo->entries_size -= off;
1754
1755         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1756         if (ret)
1757                 return ret;
1758
1759         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1760                 const void *hookptr = info->hook_entry[i];
1761                 if (info->hook_entry[i] &&
1762                     (e < (struct ebt_entry *)(base - hookptr))) {
1763                         newinfo->hook_entry[i] -= off;
1764                         pr_debug("0x%08X -> 0x%08X\n",
1765                                         newinfo->hook_entry[i] + off,
1766                                         newinfo->hook_entry[i]);
1767                 }
1768         }
1769
1770         return 0;
1771 }
1772
1773 static int ebt_compat_init_offsets(unsigned int number)
1774 {
1775         if (number > INT_MAX)
1776                 return -EINVAL;
1777
1778         /* also count the base chain policies */
1779         number += NF_BR_NUMHOOKS;
1780
1781         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1782 }
1783
1784 static int compat_table_info(const struct ebt_table_info *info,
1785                              struct compat_ebt_replace *newinfo)
1786 {
1787         unsigned int size = info->entries_size;
1788         const void *entries = info->entries;
1789         int ret;
1790
1791         newinfo->entries_size = size;
1792         ret = ebt_compat_init_offsets(info->nentries);
1793         if (ret)
1794                 return ret;
1795
1796         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1797                                                         entries, newinfo);
1798 }
1799
1800 static int compat_copy_everything_to_user(struct ebt_table *t,
1801                                           void __user *user, int *len, int cmd)
1802 {
1803         struct compat_ebt_replace repl, tmp;
1804         struct ebt_counter *oldcounters;
1805         struct ebt_table_info tinfo;
1806         int ret;
1807         void __user *pos;
1808
1809         memset(&tinfo, 0, sizeof(tinfo));
1810
1811         if (cmd == EBT_SO_GET_ENTRIES) {
1812                 tinfo.entries_size = t->private->entries_size;
1813                 tinfo.nentries = t->private->nentries;
1814                 tinfo.entries = t->private->entries;
1815                 oldcounters = t->private->counters;
1816         } else {
1817                 tinfo.entries_size = t->table->entries_size;
1818                 tinfo.nentries = t->table->nentries;
1819                 tinfo.entries = t->table->entries;
1820                 oldcounters = t->table->counters;
1821         }
1822
1823         if (copy_from_user(&tmp, user, sizeof(tmp)))
1824                 return -EFAULT;
1825
1826         if (tmp.nentries != tinfo.nentries ||
1827            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1828                 return -EINVAL;
1829
1830         memcpy(&repl, &tmp, sizeof(repl));
1831         if (cmd == EBT_SO_GET_ENTRIES)
1832                 ret = compat_table_info(t->private, &repl);
1833         else
1834                 ret = compat_table_info(&tinfo, &repl);
1835         if (ret)
1836                 return ret;
1837
1838         if (*len != sizeof(tmp) + repl.entries_size +
1839            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1840                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1841                                 *len, tinfo.entries_size, repl.entries_size);
1842                 return -EINVAL;
1843         }
1844
1845         /* userspace might not need the counters */
1846         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1847                                         tmp.num_counters, tinfo.nentries);
1848         if (ret)
1849                 return ret;
1850
1851         pos = compat_ptr(tmp.entries);
1852         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1853                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1854 }
1855
1856 struct ebt_entries_buf_state {
1857         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1858         u32 buf_kern_len;       /* total size of kernel buffer */
1859         u32 buf_kern_offset;    /* amount of data copied so far */
1860         u32 buf_user_offset;    /* read position in userspace buffer */
1861 };
1862
1863 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1864 {
1865         state->buf_kern_offset += sz;
1866         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1867 }
1868
1869 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1870                        void *data, unsigned int sz)
1871 {
1872         if (state->buf_kern_start == NULL)
1873                 goto count_only;
1874
1875         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1876                 return -EINVAL;
1877
1878         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1879
1880  count_only:
1881         state->buf_user_offset += sz;
1882         return ebt_buf_count(state, sz);
1883 }
1884
1885 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1886 {
1887         char *b = state->buf_kern_start;
1888
1889         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1890                 return -EINVAL;
1891
1892         if (b != NULL && sz > 0)
1893                 memset(b + state->buf_kern_offset, 0, sz);
1894         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1895         return ebt_buf_count(state, sz);
1896 }
1897
1898 enum compat_mwt {
1899         EBT_COMPAT_MATCH,
1900         EBT_COMPAT_WATCHER,
1901         EBT_COMPAT_TARGET,
1902 };
1903
1904 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1905                                 enum compat_mwt compat_mwt,
1906                                 struct ebt_entries_buf_state *state,
1907                                 const unsigned char *base)
1908 {
1909         char name[EBT_EXTENSION_MAXNAMELEN];
1910         struct xt_match *match;
1911         struct xt_target *wt;
1912         void *dst = NULL;
1913         int off, pad = 0;
1914         unsigned int size_kern, match_size = mwt->match_size;
1915
1916         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1917                 return -EINVAL;
1918
1919         if (state->buf_kern_start)
1920                 dst = state->buf_kern_start + state->buf_kern_offset;
1921
1922         switch (compat_mwt) {
1923         case EBT_COMPAT_MATCH:
1924                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1925                                               mwt->u.revision);
1926                 if (IS_ERR(match))
1927                         return PTR_ERR(match);
1928
1929                 off = ebt_compat_match_offset(match, match_size);
1930                 if (dst) {
1931                         if (match->compat_from_user)
1932                                 match->compat_from_user(dst, mwt->data);
1933                         else
1934                                 memcpy(dst, mwt->data, match_size);
1935                 }
1936
1937                 size_kern = match->matchsize;
1938                 if (unlikely(size_kern == -1))
1939                         size_kern = match_size;
1940                 module_put(match->me);
1941                 break;
1942         case EBT_COMPAT_WATCHER: /* fallthrough */
1943         case EBT_COMPAT_TARGET:
1944                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1945                                             mwt->u.revision);
1946                 if (IS_ERR(wt))
1947                         return PTR_ERR(wt);
1948                 off = xt_compat_target_offset(wt);
1949
1950                 if (dst) {
1951                         if (wt->compat_from_user)
1952                                 wt->compat_from_user(dst, mwt->data);
1953                         else
1954                                 memcpy(dst, mwt->data, match_size);
1955                 }
1956
1957                 size_kern = wt->targetsize;
1958                 module_put(wt->me);
1959                 break;
1960
1961         default:
1962                 return -EINVAL;
1963         }
1964
1965         state->buf_kern_offset += match_size + off;
1966         state->buf_user_offset += match_size;
1967         pad = XT_ALIGN(size_kern) - size_kern;
1968
1969         if (pad > 0 && dst) {
1970                 if (WARN_ON(state->buf_kern_len <= pad))
1971                         return -EINVAL;
1972                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
1973                         return -EINVAL;
1974                 memset(dst + size_kern, 0, pad);
1975         }
1976         return off + match_size;
1977 }
1978
1979 /* return size of all matches, watchers or target, including necessary
1980  * alignment and padding.
1981  */
1982 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1983                         unsigned int size_left, enum compat_mwt type,
1984                         struct ebt_entries_buf_state *state, const void *base)
1985 {
1986         int growth = 0;
1987         char *buf;
1988
1989         if (size_left == 0)
1990                 return 0;
1991
1992         buf = (char *) match32;
1993
1994         while (size_left >= sizeof(*match32)) {
1995                 struct ebt_entry_match *match_kern;
1996                 int ret;
1997
1998                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1999                 if (match_kern) {
2000                         char *tmp;
2001                         tmp = state->buf_kern_start + state->buf_kern_offset;
2002                         match_kern = (struct ebt_entry_match *) tmp;
2003                 }
2004                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2005                 if (ret < 0)
2006                         return ret;
2007                 size_left -= sizeof(*match32);
2008
2009                 /* add padding before match->data (if any) */
2010                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2011                 if (ret < 0)
2012                         return ret;
2013
2014                 if (match32->match_size > size_left)
2015                         return -EINVAL;
2016
2017                 size_left -= match32->match_size;
2018
2019                 ret = compat_mtw_from_user(match32, type, state, base);
2020                 if (ret < 0)
2021                         return ret;
2022
2023                 if (WARN_ON(ret < match32->match_size))
2024                         return -EINVAL;
2025                 growth += ret - match32->match_size;
2026                 growth += ebt_compat_entry_padsize();
2027
2028                 buf += sizeof(*match32);
2029                 buf += match32->match_size;
2030
2031                 if (match_kern)
2032                         match_kern->match_size = ret;
2033
2034                 /* rule should have no remaining data after target */
2035                 if (type == EBT_COMPAT_TARGET && size_left)
2036                         return -EINVAL;
2037
2038                 match32 = (struct compat_ebt_entry_mwt *) buf;
2039         }
2040
2041         return growth;
2042 }
2043
2044 /* called for all ebt_entry structures. */
2045 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2046                           unsigned int *total,
2047                           struct ebt_entries_buf_state *state)
2048 {
2049         unsigned int i, j, startoff, new_offset = 0;
2050         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2051         unsigned int offsets[4];
2052         unsigned int *offsets_update = NULL;
2053         int ret;
2054         char *buf_start;
2055
2056         if (*total < sizeof(struct ebt_entries))
2057                 return -EINVAL;
2058
2059         if (!entry->bitmask) {
2060                 *total -= sizeof(struct ebt_entries);
2061                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2062         }
2063         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2064                 return -EINVAL;
2065
2066         startoff = state->buf_user_offset;
2067         /* pull in most part of ebt_entry, it does not need to be changed. */
2068         ret = ebt_buf_add(state, entry,
2069                         offsetof(struct ebt_entry, watchers_offset));
2070         if (ret < 0)
2071                 return ret;
2072
2073         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2074         memcpy(&offsets[1], &entry->watchers_offset,
2075                         sizeof(offsets) - sizeof(offsets[0]));
2076
2077         if (state->buf_kern_start) {
2078                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2079                 offsets_update = (unsigned int *) buf_start;
2080         }
2081         ret = ebt_buf_add(state, &offsets[1],
2082                         sizeof(offsets) - sizeof(offsets[0]));
2083         if (ret < 0)
2084                 return ret;
2085         buf_start = (char *) entry;
2086         /* 0: matches offset, always follows ebt_entry.
2087          * 1: watchers offset, from ebt_entry structure
2088          * 2: target offset, from ebt_entry structure
2089          * 3: next ebt_entry offset, from ebt_entry structure
2090          *
2091          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2092          */
2093         for (i = 0; i < 4 ; ++i) {
2094                 if (offsets[i] > *total)
2095                         return -EINVAL;
2096
2097                 if (i < 3 && offsets[i] == *total)
2098                         return -EINVAL;
2099
2100                 if (i == 0)
2101                         continue;
2102                 if (offsets[i-1] > offsets[i])
2103                         return -EINVAL;
2104         }
2105
2106         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2107                 struct compat_ebt_entry_mwt *match32;
2108                 unsigned int size;
2109                 char *buf = buf_start + offsets[i];
2110
2111                 if (offsets[i] > offsets[j])
2112                         return -EINVAL;
2113
2114                 match32 = (struct compat_ebt_entry_mwt *) buf;
2115                 size = offsets[j] - offsets[i];
2116                 ret = ebt_size_mwt(match32, size, i, state, base);
2117                 if (ret < 0)
2118                         return ret;
2119                 new_offset += ret;
2120                 if (offsets_update && new_offset) {
2121                         pr_debug("change offset %d to %d\n",
2122                                 offsets_update[i], offsets[j] + new_offset);
2123                         offsets_update[i] = offsets[j] + new_offset;
2124                 }
2125         }
2126
2127         if (state->buf_kern_start == NULL) {
2128                 unsigned int offset = buf_start - (char *) base;
2129
2130                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2131                 if (ret < 0)
2132                         return ret;
2133         }
2134
2135         startoff = state->buf_user_offset - startoff;
2136
2137         if (WARN_ON(*total < startoff))
2138                 return -EINVAL;
2139         *total -= startoff;
2140         return 0;
2141 }
2142
2143 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2144  * It might need more memory when copied to a 64 bit kernel in case
2145  * userspace is 32-bit. So, first task: find out how much memory is needed.
2146  *
2147  * Called before validation is performed.
2148  */
2149 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2150                                 struct ebt_entries_buf_state *state)
2151 {
2152         unsigned int size_remaining = size_user;
2153         int ret;
2154
2155         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2156                                         &size_remaining, state);
2157         if (ret < 0)
2158                 return ret;
2159
2160         if (size_remaining)
2161                 return -EINVAL;
2162
2163         return state->buf_kern_offset;
2164 }
2165
2166
2167 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2168                                             void __user *user, unsigned int len)
2169 {
2170         struct compat_ebt_replace tmp;
2171         int i;
2172
2173         if (len < sizeof(tmp))
2174                 return -EINVAL;
2175
2176         if (copy_from_user(&tmp, user, sizeof(tmp)))
2177                 return -EFAULT;
2178
2179         if (len != sizeof(tmp) + tmp.entries_size)
2180                 return -EINVAL;
2181
2182         if (tmp.entries_size == 0)
2183                 return -EINVAL;
2184
2185         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2186                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2187                 return -ENOMEM;
2188         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2189                 return -ENOMEM;
2190
2191         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2192
2193         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2194         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2195                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2196
2197         repl->num_counters = tmp.num_counters;
2198         repl->counters = compat_ptr(tmp.counters);
2199         repl->entries = compat_ptr(tmp.entries);
2200         return 0;
2201 }
2202
2203 static int compat_do_replace(struct net *net, void __user *user,
2204                              unsigned int len)
2205 {
2206         int ret, i, countersize, size64;
2207         struct ebt_table_info *newinfo;
2208         struct ebt_replace tmp;
2209         struct ebt_entries_buf_state state;
2210         void *entries_tmp;
2211
2212         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2213         if (ret) {
2214                 /* try real handler in case userland supplied needed padding */
2215                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2216                         ret = 0;
2217                 return ret;
2218         }
2219
2220         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2221         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2222         if (!newinfo)
2223                 return -ENOMEM;
2224
2225         if (countersize)
2226                 memset(newinfo->counters, 0, countersize);
2227
2228         memset(&state, 0, sizeof(state));
2229
2230         newinfo->entries = vmalloc(tmp.entries_size);
2231         if (!newinfo->entries) {
2232                 ret = -ENOMEM;
2233                 goto free_newinfo;
2234         }
2235         if (copy_from_user(
2236            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2237                 ret = -EFAULT;
2238                 goto free_entries;
2239         }
2240
2241         entries_tmp = newinfo->entries;
2242
2243         xt_compat_lock(NFPROTO_BRIDGE);
2244
2245         ret = ebt_compat_init_offsets(tmp.nentries);
2246         if (ret < 0)
2247                 goto out_unlock;
2248
2249         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2250         if (ret < 0)
2251                 goto out_unlock;
2252
2253         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2254                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2255                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2256
2257         size64 = ret;
2258         newinfo->entries = vmalloc(size64);
2259         if (!newinfo->entries) {
2260                 vfree(entries_tmp);
2261                 ret = -ENOMEM;
2262                 goto out_unlock;
2263         }
2264
2265         memset(&state, 0, sizeof(state));
2266         state.buf_kern_start = newinfo->entries;
2267         state.buf_kern_len = size64;
2268
2269         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2270         if (WARN_ON(ret < 0)) {
2271                 vfree(entries_tmp);
2272                 goto out_unlock;
2273         }
2274
2275         vfree(entries_tmp);
2276         tmp.entries_size = size64;
2277
2278         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2279                 char __user *usrptr;
2280                 if (tmp.hook_entry[i]) {
2281                         unsigned int delta;
2282                         usrptr = (char __user *) tmp.hook_entry[i];
2283                         delta = usrptr - tmp.entries;
2284                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2285                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2286                 }
2287         }
2288
2289         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2290         xt_compat_unlock(NFPROTO_BRIDGE);
2291
2292         ret = do_replace_finish(net, &tmp, newinfo);
2293         if (ret == 0)
2294                 return ret;
2295 free_entries:
2296         vfree(newinfo->entries);
2297 free_newinfo:
2298         vfree(newinfo);
2299         return ret;
2300 out_unlock:
2301         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2302         xt_compat_unlock(NFPROTO_BRIDGE);
2303         goto free_entries;
2304 }
2305
2306 static int compat_update_counters(struct net *net, void __user *user,
2307                                   unsigned int len)
2308 {
2309         struct compat_ebt_replace hlp;
2310
2311         if (copy_from_user(&hlp, user, sizeof(hlp)))
2312                 return -EFAULT;
2313
2314         /* try real handler in case userland supplied needed padding */
2315         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2316                 return update_counters(net, user, len);
2317
2318         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2319                                         hlp.num_counters, user, len);
2320 }
2321
2322 static int compat_do_ebt_set_ctl(struct sock *sk,
2323                 int cmd, void __user *user, unsigned int len)
2324 {
2325         int ret;
2326         struct net *net = sock_net(sk);
2327
2328         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2329                 return -EPERM;
2330
2331         switch (cmd) {
2332         case EBT_SO_SET_ENTRIES:
2333                 ret = compat_do_replace(net, user, len);
2334                 break;
2335         case EBT_SO_SET_COUNTERS:
2336                 ret = compat_update_counters(net, user, len);
2337                 break;
2338         default:
2339                 ret = -EINVAL;
2340         }
2341         return ret;
2342 }
2343
2344 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2345                 void __user *user, int *len)
2346 {
2347         int ret;
2348         struct compat_ebt_replace tmp;
2349         struct ebt_table *t;
2350         struct net *net = sock_net(sk);
2351
2352         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2353                 return -EPERM;
2354
2355         /* try real handler in case userland supplied needed padding */
2356         if ((cmd == EBT_SO_GET_INFO ||
2357              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2358                         return do_ebt_get_ctl(sk, cmd, user, len);
2359
2360         if (copy_from_user(&tmp, user, sizeof(tmp)))
2361                 return -EFAULT;
2362
2363         tmp.name[sizeof(tmp.name) - 1] = '\0';
2364
2365         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2366         if (!t)
2367                 return ret;
2368
2369         xt_compat_lock(NFPROTO_BRIDGE);
2370         switch (cmd) {
2371         case EBT_SO_GET_INFO:
2372                 tmp.nentries = t->private->nentries;
2373                 ret = compat_table_info(t->private, &tmp);
2374                 if (ret)
2375                         goto out;
2376                 tmp.valid_hooks = t->valid_hooks;
2377
2378                 if (copy_to_user(user, &tmp, *len) != 0) {
2379                         ret = -EFAULT;
2380                         break;
2381                 }
2382                 ret = 0;
2383                 break;
2384         case EBT_SO_GET_INIT_INFO:
2385                 tmp.nentries = t->table->nentries;
2386                 tmp.entries_size = t->table->entries_size;
2387                 tmp.valid_hooks = t->table->valid_hooks;
2388
2389                 if (copy_to_user(user, &tmp, *len) != 0) {
2390                         ret = -EFAULT;
2391                         break;
2392                 }
2393                 ret = 0;
2394                 break;
2395         case EBT_SO_GET_ENTRIES:
2396         case EBT_SO_GET_INIT_ENTRIES:
2397                 /* try real handler first in case of userland-side padding.
2398                  * in case we are dealing with an 'ordinary' 32 bit binary
2399                  * without 64bit compatibility padding, this will fail right
2400                  * after copy_from_user when the *len argument is validated.
2401                  *
2402                  * the compat_ variant needs to do one pass over the kernel
2403                  * data set to adjust for size differences before it the check.
2404                  */
2405                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2406                         ret = 0;
2407                 else
2408                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2409                 break;
2410         default:
2411                 ret = -EINVAL;
2412         }
2413  out:
2414         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2415         xt_compat_unlock(NFPROTO_BRIDGE);
2416         mutex_unlock(&ebt_mutex);
2417         return ret;
2418 }
2419 #endif
2420
2421 static struct nf_sockopt_ops ebt_sockopts = {
2422         .pf             = PF_INET,
2423         .set_optmin     = EBT_BASE_CTL,
2424         .set_optmax     = EBT_SO_SET_MAX + 1,
2425         .set            = do_ebt_set_ctl,
2426 #ifdef CONFIG_COMPAT
2427         .compat_set     = compat_do_ebt_set_ctl,
2428 #endif
2429         .get_optmin     = EBT_BASE_CTL,
2430         .get_optmax     = EBT_SO_GET_MAX + 1,
2431         .get            = do_ebt_get_ctl,
2432 #ifdef CONFIG_COMPAT
2433         .compat_get     = compat_do_ebt_get_ctl,
2434 #endif
2435         .owner          = THIS_MODULE,
2436 };
2437
2438 static int __init ebtables_init(void)
2439 {
2440         int ret;
2441
2442         ret = xt_register_target(&ebt_standard_target);
2443         if (ret < 0)
2444                 return ret;
2445         ret = nf_register_sockopt(&ebt_sockopts);
2446         if (ret < 0) {
2447                 xt_unregister_target(&ebt_standard_target);
2448                 return ret;
2449         }
2450
2451         return 0;
2452 }
2453
2454 static void __exit ebtables_fini(void)
2455 {
2456         nf_unregister_sockopt(&ebt_sockopts);
2457         xt_unregister_target(&ebt_standard_target);
2458 }
2459
2460 EXPORT_SYMBOL(ebt_register_table);
2461 EXPORT_SYMBOL(ebt_unregister_table);
2462 EXPORT_SYMBOL(ebt_do_table);
2463 module_init(ebtables_init);
2464 module_exit(ebtables_fini);
2465 MODULE_LICENSE("GPL");