net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is strongly inspired by the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  37
  38 /* Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48                                  COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_action_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 /* Do some firewalling */
 181 unsigned int ebt_do_table(struct sk_buff *skb,
 182                           const struct nf_hook_state *state,
 183                           struct ebt_table *table)
 184 {
 185         unsigned int hook = state->hook;
 186         int i, nentries;
 187         struct ebt_entry *point;
 188         struct ebt_counter *counter_base, *cb_base;
 189         const struct ebt_entry_target *t;
 190         int verdict, sp = 0;
 191         struct ebt_chainstack *cs;
 192         struct ebt_entries *chaininfo;
 193         const char *base;
 194         const struct ebt_table_info *private;
 195         struct xt_action_param acpar;
 196
 197         acpar.state   = state;
 198         acpar.hotdrop = false;
 199
 200         read_lock_bh(&table->lock);
 201         private = table->private;
 202         cb_base = COUNTER_BASE(private->counters, private->nentries,
 203            smp_processor_id());
 204         if (private->chainstack)
 205                 cs = private->chainstack[smp_processor_id()];
 206         else
 207                 cs = NULL;
 208         chaininfo = private->hook_entry[hook];
 209         nentries = private->hook_entry[hook]->nentries;
 210         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 211         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 212         /* base for chain jumps */
 213         base = private->entries;
 214         i = 0;
 215         while (i < nentries) {
 216                 if (ebt_basic_match(point, skb, state->in, state->out))
 217                         goto letscontinue;
 218
 219                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 220                         goto letscontinue;
 221                 if (acpar.hotdrop) {
 222                         read_unlock_bh(&table->lock);
 223                         return NF_DROP;
 224                 }
 225
 226                 /* increase counter */
 227                 (*(counter_base + i)).pcnt++;
 228                 (*(counter_base + i)).bcnt += skb->len;
 229
 230                 /* these should only watch: not modify, nor tell us
 231                  * what to do with the packet
 232                  */
 233                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 234
 235                 t = (struct ebt_entry_target *)
 236                    (((char *)point) + point->target_offset);
 237                 /* standard target */
 238                 if (!t->u.target->target)
 239                         verdict = ((struct ebt_standard_target *)t)->verdict;
 240                 else {
 241                         acpar.target   = t->u.target;
 242                         acpar.targinfo = t->data;
 243                         verdict = t->u.target->target(skb, &acpar);
 244                 }
 245                 if (verdict == EBT_ACCEPT) {
 246                         read_unlock_bh(&table->lock);
 247                         return NF_ACCEPT;
 248                 }
 249                 if (verdict == EBT_DROP) {
 250                         read_unlock_bh(&table->lock);
 251                         return NF_DROP;
 252                 }
 253                 if (verdict == EBT_RETURN) {
 254 letsreturn:
 255                         if (WARN(sp == 0, "RETURN on base chain")) {
 256                                 /* act like this is EBT_CONTINUE */
 257                                 goto letscontinue;
 258                         }
 259
 260                         sp--;
 261                         /* put all the local variables right */
 262                         i = cs[sp].n;
 263                         chaininfo = cs[sp].chaininfo;
 264                         nentries = chaininfo->nentries;
 265                         point = cs[sp].e;
 266                         counter_base = cb_base +
 267                            chaininfo->counter_offset;
 268                         continue;
 269                 }
 270                 if (verdict == EBT_CONTINUE)
 271                         goto letscontinue;
 272
 273                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 274                         read_unlock_bh(&table->lock);
 275                         return NF_DROP;
 276                 }
 277
 278                 /* jump to a udc */
 279                 cs[sp].n = i + 1;
 280                 cs[sp].chaininfo = chaininfo;
 281                 cs[sp].e = ebt_next_entry(point);
 282                 i = 0;
 283                 chaininfo = (struct ebt_entries *) (base + verdict);
 284
 285                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 286                         read_unlock_bh(&table->lock);
 287                         return NF_DROP;
 288                 }
 289
 290                 nentries = chaininfo->nentries;
 291                 point = (struct ebt_entry *)chaininfo->data;
 292                 counter_base = cb_base + chaininfo->counter_offset;
 293                 sp++;
 294                 continue;
 295 letscontinue:
 296                 point = ebt_next_entry(point);
 297                 i++;
 298         }
 299
 300         /* I actually like this :) */
 301         if (chaininfo->policy == EBT_RETURN)
 302                 goto letsreturn;
 303         if (chaininfo->policy == EBT_ACCEPT) {
 304                 read_unlock_bh(&table->lock);
 305                 return NF_ACCEPT;
 306         }
 307         read_unlock_bh(&table->lock);
 308         return NF_DROP;
 309 }
 310
 311 /* If it succeeds, returns element and locks mutex */
 312 static inline void *
 313 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 314                         struct mutex *mutex)
 315 {
 316         struct {
 317                 struct list_head list;
 318                 char name[EBT_FUNCTION_MAXNAMELEN];
 319         } *e;
 320
 321         mutex_lock(mutex);
 322         list_for_each_entry(e, head, list) {
 323                 if (strcmp(e->name, name) == 0)
 324                         return e;
 325         }
 326         *error = -ENOENT;
 327         mutex_unlock(mutex);
 328         return NULL;
 329 }
 330
 331 static void *
 332 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 333                  int *error, struct mutex *mutex)
 334 {
 335         return try_then_request_module(
 336                         find_inlist_lock_noload(head, name, error, mutex),
 337                         "%s%s", prefix, name);
 338 }
 339
 340 static inline struct ebt_table *
 341 find_table_lock(struct net *net, const char *name, int *error,
 342                 struct mutex *mutex)
 343 {
 344         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 345                                 "ebtable_", error, mutex);
 346 }
 347
 348 static inline int
 349 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 350                 unsigned int *cnt)
 351 {
 352         const struct ebt_entry *e = par->entryinfo;
 353         struct xt_match *match;
 354         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 355         int ret;
 356
 357         if (left < sizeof(struct ebt_entry_match) ||
 358             left - sizeof(struct ebt_entry_match) < m->match_size)
 359                 return -EINVAL;
 360
 361         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 362         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 363                 if (!IS_ERR(match))
 364                         module_put(match->me);
 365                 request_module("ebt_%s", m->u.name);
 366                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
 367         }
 368         if (IS_ERR(match))
 369                 return PTR_ERR(match);
 370         m->u.match = match;
 371
 372         par->match     = match;
 373         par->matchinfo = m->data;
 374         ret = xt_check_match(par, m->match_size,
 375               e->ethproto, e->invflags & EBT_IPROTO);
 376         if (ret < 0) {
 377                 module_put(match->me);
 378                 return ret;
 379         }
 380
 381         (*cnt)++;
 382         return 0;
 383 }
 384
 385 static inline int
 386 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 387                   unsigned int *cnt)
 388 {
 389         const struct ebt_entry *e = par->entryinfo;
 390         struct xt_target *watcher;
 391         size_t left = ((char *)e + e->target_offset) - (char *)w;
 392         int ret;
 393
 394         if (left < sizeof(struct ebt_entry_watcher) ||
 395            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 396                 return -EINVAL;
 397
 398         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 399         if (IS_ERR(watcher))
 400                 return PTR_ERR(watcher);
 401         w->u.watcher = watcher;
 402
 403         par->target   = watcher;
 404         par->targinfo = w->data;
 405         ret = xt_check_target(par, w->watcher_size,
 406               e->ethproto, e->invflags & EBT_IPROTO);
 407         if (ret < 0) {
 408                 module_put(watcher->me);
 409                 return ret;
 410         }
 411
 412         (*cnt)++;
 413         return 0;
 414 }
 415
 416 static int ebt_verify_pointers(const struct ebt_replace *repl,
 417                                struct ebt_table_info *newinfo)
 418 {
 419         unsigned int limit = repl->entries_size;
 420         unsigned int valid_hooks = repl->valid_hooks;
 421         unsigned int offset = 0;
 422         int i;
 423
 424         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 425                 newinfo->hook_entry[i] = NULL;
 426
 427         newinfo->entries_size = repl->entries_size;
 428         newinfo->nentries = repl->nentries;
 429
 430         while (offset < limit) {
 431                 size_t left = limit - offset;
 432                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 433
 434                 if (left < sizeof(unsigned int))
 435                         break;
 436
 437                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 438                         if ((valid_hooks & (1 << i)) == 0)
 439                                 continue;
 440                         if ((char __user *)repl->hook_entry[i] ==
 441                              repl->entries + offset)
 442                                 break;
 443                 }
 444
 445                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 446                         if (e->bitmask != 0) {
 447                                 /* we make userspace set this right,
 448                                  * so there is no misunderstanding
 449                                  */
 450                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 451                                          "in distinguisher\n");
 452                                 return -EINVAL;
 453                         }
 454                         if (i != NF_BR_NUMHOOKS)
 455                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 456                         if (left < sizeof(struct ebt_entries))
 457                                 break;
 458                         offset += sizeof(struct ebt_entries);
 459                 } else {
 460                         if (left < sizeof(struct ebt_entry))
 461                                 break;
 462                         if (left < e->next_offset)
 463                                 break;
 464                         if (e->next_offset < sizeof(struct ebt_entry))
 465                                 return -EINVAL;
 466                         offset += e->next_offset;
 467                 }
 468         }
 469         if (offset != limit) {
 470                 BUGPRINT("entries_size too small\n");
 471                 return -EINVAL;
 472         }
 473
 474         /* check if all valid hooks have a chain */
 475         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 476                 if (!newinfo->hook_entry[i] &&
 477                    (valid_hooks & (1 << i))) {
 478                         BUGPRINT("Valid hook without chain\n");
 479                         return -EINVAL;
 480                 }
 481         }
 482         return 0;
 483 }
 484
 485 /* this one is very careful, as it is the first function
 486  * to parse the userspace data
 487  */
 488 static inline int
 489 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 490                                const struct ebt_table_info *newinfo,
 491                                unsigned int *n, unsigned int *cnt,
 492                                unsigned int *totalcnt, unsigned int *udc_cnt)
 493 {
 494         int i;
 495
 496         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 497                 if ((void *)e == (void *)newinfo->hook_entry[i])
 498                         break;
 499         }
 500         /* beginning of a new chain
 501          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 502          */
 503         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 504                 /* this checks if the previous chain has as many entries
 505                  * as it said it has
 506                  */
 507                 if (*n != *cnt) {
 508                         BUGPRINT("nentries does not equal the nr of entries "
 509                                  "in the chain\n");
 510                         return -EINVAL;
 511                 }
 512                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 513                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 514                         /* only RETURN from udc */
 515                         if (i != NF_BR_NUMHOOKS ||
 516                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 517                                 BUGPRINT("bad policy\n");
 518                                 return -EINVAL;
 519                         }
 520                 }
 521                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 522                         (*udc_cnt)++;
 523                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 524                         BUGPRINT("counter_offset != totalcnt");
 525                         return -EINVAL;
 526                 }
 527                 *n = ((struct ebt_entries *)e)->nentries;
 528                 *cnt = 0;
 529                 return 0;
 530         }
 531         /* a plain old entry, heh */
 532         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 533            e->watchers_offset > e->target_offset ||
 534            e->target_offset >= e->next_offset) {
 535                 BUGPRINT("entry offsets not in right order\n");
 536                 return -EINVAL;
 537         }
 538         /* this is not checked anywhere else */
 539         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 540                 BUGPRINT("target size too small\n");
 541                 return -EINVAL;
 542         }
 543         (*cnt)++;
 544         (*totalcnt)++;
 545         return 0;
 546 }
 547
 548 struct ebt_cl_stack {
 549         struct ebt_chainstack cs;
 550         int from;
 551         unsigned int hookmask;
 552 };
 553
 554 /* We need these positions to check that the jumps to a different part of the
 555  * entries is a jump to the beginning of a new chain.
 556  */
 557 static inline int
 558 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 559                       unsigned int *n, struct ebt_cl_stack *udc)
 560 {
 561         int i;
 562
 563         /* we're only interested in chain starts */
 564         if (e->bitmask)
 565                 return 0;
 566         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 567                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 568                         break;
 569         }
 570         /* only care about udc */
 571         if (i != NF_BR_NUMHOOKS)
 572                 return 0;
 573
 574         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 575         /* these initialisations are depended on later in check_chainloops() */
 576         udc[*n].cs.n = 0;
 577         udc[*n].hookmask = 0;
 578
 579         (*n)++;
 580         return 0;
 581 }
 582
 583 static inline int
 584 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 585 {
 586         struct xt_mtdtor_param par;
 587
 588         if (i && (*i)-- == 0)
 589                 return 1;
 590
 591         par.net       = net;
 592         par.match     = m->u.match;
 593         par.matchinfo = m->data;
 594         par.family    = NFPROTO_BRIDGE;
 595         if (par.match->destroy != NULL)
 596                 par.match->destroy(&par);
 597         module_put(par.match->me);
 598         return 0;
 599 }
 600
 601 static inline int
 602 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 603 {
 604         struct xt_tgdtor_param par;
 605
 606         if (i && (*i)-- == 0)
 607                 return 1;
 608
 609         par.net      = net;
 610         par.target   = w->u.watcher;
 611         par.targinfo = w->data;
 612         par.family   = NFPROTO_BRIDGE;
 613         if (par.target->destroy != NULL)
 614                 par.target->destroy(&par);
 615         module_put(par.target->me);
 616         return 0;
 617 }
 618
 619 static inline int
 620 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 621 {
 622         struct xt_tgdtor_param par;
 623         struct ebt_entry_target *t;
 624
 625         if (e->bitmask == 0)
 626                 return 0;
 627         /* we're done */
 628         if (cnt && (*cnt)-- == 0)
 629                 return 1;
 630         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 631         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 632         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 633
 634         par.net      = net;
 635         par.target   = t->u.target;
 636         par.targinfo = t->data;
 637         par.family   = NFPROTO_BRIDGE;
 638         if (par.target->destroy != NULL)
 639                 par.target->destroy(&par);
 640         module_put(par.target->me);
 641         return 0;
 642 }
 643
 644 static inline int
 645 ebt_check_entry(struct ebt_entry *e, struct net *net,
 646                 const struct ebt_table_info *newinfo,
 647                 const char *name, unsigned int *cnt,
 648                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 649 {
 650         struct ebt_entry_target *t;
 651         struct xt_target *target;
 652         unsigned int i, j, hook = 0, hookmask = 0;
 653         size_t gap;
 654         int ret;
 655         struct xt_mtchk_param mtpar;
 656         struct xt_tgchk_param tgpar;
 657
 658         /* don't mess with the struct ebt_entries */
 659         if (e->bitmask == 0)
 660                 return 0;
 661
 662         if (e->bitmask & ~EBT_F_MASK) {
 663                 BUGPRINT("Unknown flag for bitmask\n");
 664                 return -EINVAL;
 665         }
 666         if (e->invflags & ~EBT_INV_MASK) {
 667                 BUGPRINT("Unknown flag for inv bitmask\n");
 668                 return -EINVAL;
 669         }
 670         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 671                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 672                 return -EINVAL;
 673         }
 674         /* what hook do we belong to? */
 675         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 676                 if (!newinfo->hook_entry[i])
 677                         continue;
 678                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 679                         hook = i;
 680                 else
 681                         break;
 682         }
 683         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 684          * a base chain
 685          */
 686         if (i < NF_BR_NUMHOOKS)
 687                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 688         else {
 689                 for (i = 0; i < udc_cnt; i++)
 690                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 691                                 break;
 692                 if (i == 0)
 693                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 694                 else
 695                         hookmask = cl_s[i - 1].hookmask;
 696         }
 697         i = 0;
 698
 699         mtpar.net       = tgpar.net       = net;
 700         mtpar.table     = tgpar.table     = name;
 701         mtpar.entryinfo = tgpar.entryinfo = e;
 702         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 703         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 704         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 705         if (ret != 0)
 706                 goto cleanup_matches;
 707         j = 0;
 708         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 709         if (ret != 0)
 710                 goto cleanup_watchers;
 711         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
 712         gap = e->next_offset - e->target_offset;
 713
 714         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 715         if (IS_ERR(target)) {
 716                 ret = PTR_ERR(target);
 717                 goto cleanup_watchers;
 718         }
 719
 720         t->u.target = target;
 721         if (t->u.target == &ebt_standard_target) {
 722                 if (gap < sizeof(struct ebt_standard_target)) {
 723                         BUGPRINT("Standard target size too big\n");
 724                         ret = -EFAULT;
 725                         goto cleanup_watchers;
 726                 }
 727                 if (((struct ebt_standard_target *)t)->verdict <
 728                    -NUM_STANDARD_TARGETS) {
 729                         BUGPRINT("Invalid standard target\n");
 730                         ret = -EFAULT;
 731                         goto cleanup_watchers;
 732                 }
 733         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 734                 module_put(t->u.target->me);
 735                 ret = -EFAULT;
 736                 goto cleanup_watchers;
 737         }
 738
 739         tgpar.target   = target;
 740         tgpar.targinfo = t->data;
 741         ret = xt_check_target(&tgpar, t->target_size,
 742               e->ethproto, e->invflags & EBT_IPROTO);
 743         if (ret < 0) {
 744                 module_put(target->me);
 745                 goto cleanup_watchers;
 746         }
 747         (*cnt)++;
 748         return 0;
 749 cleanup_watchers:
 750         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 751 cleanup_matches:
 752         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 753         return ret;
 754 }
 755
 756 /* checks for loops and sets the hook mask for udc
 757  * the hook mask for udc tells us from which base chains the udc can be
 758  * accessed. This mask is a parameter to the check() functions of the extensions
 759  */
 760 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 761                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 762 {
 763         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 764         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 765         const struct ebt_entry_target *t;
 766
 767         while (pos < nentries || chain_nr != -1) {
 768                 /* end of udc, go back one 'recursion' step */
 769                 if (pos == nentries) {
 770                         /* put back values of the time when this chain was called */
 771                         e = cl_s[chain_nr].cs.e;
 772                         if (cl_s[chain_nr].from != -1)
 773                                 nentries =
 774                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 775                         else
 776                                 nentries = chain->nentries;
 777                         pos = cl_s[chain_nr].cs.n;
 778                         /* make sure we won't see a loop that isn't one */
 779                         cl_s[chain_nr].cs.n = 0;
 780                         chain_nr = cl_s[chain_nr].from;
 781                         if (pos == nentries)
 782                                 continue;
 783                 }
 784                 t = (struct ebt_entry_target *)
 785                    (((char *)e) + e->target_offset);
 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                         BUGPRINT("Standard target size too big\n");
 791                         return -1;
 792                 }
 793                 verdict = ((struct ebt_standard_target *)t)->verdict;
 794                 if (verdict >= 0) { /* jump to another chain */
 795                         struct ebt_entries *hlp2 =
 796                            (struct ebt_entries *)(base + verdict);
 797                         for (i = 0; i < udc_cnt; i++)
 798                                 if (hlp2 == cl_s[i].cs.chaininfo)
 799                                         break;
 800                         /* bad destination or loop */
 801                         if (i == udc_cnt) {
 802                                 BUGPRINT("bad destination\n");
 803                                 return -1;
 804                         }
 805                         if (cl_s[i].cs.n) {
 806                                 BUGPRINT("loop\n");
 807                                 return -1;
 808                         }
 809                         if (cl_s[i].hookmask & (1 << hooknr))
 810                                 goto letscontinue;
 811                         /* this can't be 0, so the loop test is correct */
 812                         cl_s[i].cs.n = pos + 1;
 813                         pos = 0;
 814                         cl_s[i].cs.e = ebt_next_entry(e);
 815                         e = (struct ebt_entry *)(hlp2->data);
 816                         nentries = hlp2->nentries;
 817                         cl_s[i].from = chain_nr;
 818                         chain_nr = i;
 819                         /* this udc is accessible from the base chain for hooknr */
 820                         cl_s[i].hookmask |= (1 << hooknr);
 821                         continue;
 822                 }
 823 letscontinue:
 824                 e = ebt_next_entry(e);
 825                 pos++;
 826         }
 827         return 0;
 828 }
 829
 830 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 831 static int translate_table(struct net *net, const char *name,
 832                            struct ebt_table_info *newinfo)
 833 {
 834         unsigned int i, j, k, udc_cnt;
 835         int ret;
 836         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 837
 838         i = 0;
 839         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 840                 i++;
 841         if (i == NF_BR_NUMHOOKS) {
 842                 BUGPRINT("No valid hooks specified\n");
 843                 return -EINVAL;
 844         }
 845         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 846                 BUGPRINT("Chains don't start at beginning\n");
 847                 return -EINVAL;
 848         }
 849         /* make sure chains are ordered after each other in same order
 850          * as their corresponding hooks
 851          */
 852         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 853                 if (!newinfo->hook_entry[j])
 854                         continue;
 855                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 856                         BUGPRINT("Hook order must be followed\n");
 857                         return -EINVAL;
 858                 }
 859                 i = j;
 860         }
 861
 862         /* do some early checkings and initialize some things */
 863         i = 0; /* holds the expected nr. of entries for the chain */
 864         j = 0; /* holds the up to now counted entries for the chain */
 865         k = 0; /* holds the total nr. of entries, should equal
 866                 * newinfo->nentries afterwards
 867                 */
 868         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 869         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 870            ebt_check_entry_size_and_hooks, newinfo,
 871            &i, &j, &k, &udc_cnt);
 872
 873         if (ret != 0)
 874                 return ret;
 875
 876         if (i != j) {
 877                 BUGPRINT("nentries does not equal the nr of entries in the "
 878                          "(last) chain\n");
 879                 return -EINVAL;
 880         }
 881         if (k != newinfo->nentries) {
 882                 BUGPRINT("Total nentries is wrong\n");
 883                 return -EINVAL;
 884         }
 885
 886         /* get the location of the udc, put them in an array
 887          * while we're at it, allocate the chainstack
 888          */
 889         if (udc_cnt) {
 890                 /* this will get free'd in do_replace()/ebt_register_table()
 891                  * if an error occurs
 892                  */
 893                 newinfo->chainstack =
 894                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 895                 if (!newinfo->chainstack)
 896                         return -ENOMEM;
 897                 for_each_possible_cpu(i) {
 898                         newinfo->chainstack[i] =
 899                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 900                         if (!newinfo->chainstack[i]) {
 901                                 while (i)
 902                                         vfree(newinfo->chainstack[--i]);
 903                                 vfree(newinfo->chainstack);
 904                                 newinfo->chainstack = NULL;
 905                                 return -ENOMEM;
 906                         }
 907                 }
 908
 909                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 910                 if (!cl_s)
 911                         return -ENOMEM;
 912                 i = 0; /* the i'th udc */
 913                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 914                    ebt_get_udc_positions, newinfo, &i, cl_s);
 915                 /* sanity check */
 916                 if (i != udc_cnt) {
 917                         BUGPRINT("i != udc_cnt\n");
 918                         vfree(cl_s);
 919                         return -EFAULT;
 920                 }
 921         }
 922
 923         /* Check for loops */
 924         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 925                 if (newinfo->hook_entry[i])
 926                         if (check_chainloops(newinfo->hook_entry[i],
 927                            cl_s, udc_cnt, i, newinfo->entries)) {
 928                                 vfree(cl_s);
 929                                 return -EINVAL;
 930                         }
 931
 932         /* we now know the following (along with E=mc²):
 933          *  - the nr of entries in each chain is right
 934          *  - the size of the allocated space is right
 935          *  - all valid hooks have a corresponding chain
 936          *  - there are no loops
 937          *  - wrong data can still be on the level of a single entry
 938          *  - could be there are jumps to places that are not the
 939          *    beginning of a chain. This can only occur in chains that
 940          *    are not accessible from any base chains, so we don't care.
 941          */
 942
 943         /* used to know what we need to clean up if something goes wrong */
 944         i = 0;
 945         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 946            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 947         if (ret != 0) {
 948                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 949                                   ebt_cleanup_entry, net, &i);
 950         }
 951         vfree(cl_s);
 952         return ret;
 953 }
 954
 955 /* called under write_lock */
 956 static void get_counters(const struct ebt_counter *oldcounters,
 957                          struct ebt_counter *counters, unsigned int nentries)
 958 {
 959         int i, cpu;
 960         struct ebt_counter *counter_base;
 961
 962         /* counters of cpu 0 */
 963         memcpy(counters, oldcounters,
 964                sizeof(struct ebt_counter) * nentries);
 965
 966         /* add other counters to those of cpu 0 */
 967         for_each_possible_cpu(cpu) {
 968                 if (cpu == 0)
 969                         continue;
 970                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 971                 for (i = 0; i < nentries; i++) {
 972                         counters[i].pcnt += counter_base[i].pcnt;
 973                         counters[i].bcnt += counter_base[i].bcnt;
 974                 }
 975         }
 976 }
 977
 978 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 979                               struct ebt_table_info *newinfo)
 980 {
 981         int ret, i;
 982         struct ebt_counter *counterstmp = NULL;
 983         /* used to be able to unlock earlier */
 984         struct ebt_table_info *table;
 985         struct ebt_table *t;
 986
 987         /* the user wants counters back
 988          * the check on the size is done later, when we have the lock
 989          */
 990         if (repl->num_counters) {
 991                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
 992                 counterstmp = vmalloc(size);
 993                 if (!counterstmp)
 994                         return -ENOMEM;
 995         }
 996
 997         newinfo->chainstack = NULL;
 998         ret = ebt_verify_pointers(repl, newinfo);
 999         if (ret != 0)
1000                 goto free_counterstmp;
1001
1002         ret = translate_table(net, repl->name, newinfo);
1003
1004         if (ret != 0)
1005                 goto free_counterstmp;
1006
1007         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1008         if (!t) {
1009                 ret = -ENOENT;
1010                 goto free_iterate;
1011         }
1012
1013         /* the table doesn't like it */
1014         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1015                 goto free_unlock;
1016
1017         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1018                 BUGPRINT("Wrong nr. of counters requested\n");
1019                 ret = -EINVAL;
1020                 goto free_unlock;
1021         }
1022
1023         /* we have the mutex lock, so no danger in reading this pointer */
1024         table = t->private;
1025         /* make sure the table can only be rmmod'ed if it contains no rules */
1026         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1027                 ret = -ENOENT;
1028                 goto free_unlock;
1029         } else if (table->nentries && !newinfo->nentries)
1030                 module_put(t->me);
1031         /* we need an atomic snapshot of the counters */
1032         write_lock_bh(&t->lock);
1033         if (repl->num_counters)
1034                 get_counters(t->private->counters, counterstmp,
1035                    t->private->nentries);
1036
1037         t->private = newinfo;
1038         write_unlock_bh(&t->lock);
1039         mutex_unlock(&ebt_mutex);
1040         /* so, a user can change the chains while having messed up her counter
1041          * allocation. Only reason why this is done is because this way the lock
1042          * is held only once, while this doesn't bring the kernel into a
1043          * dangerous state.
1044          */
1045         if (repl->num_counters &&
1046            copy_to_user(repl->counters, counterstmp,
1047            repl->num_counters * sizeof(struct ebt_counter))) {
1048                 /* Silent error, can't fail, new table is already in place */
1049                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1050         }
1051
1052         /* decrease module count and free resources */
1053         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1054                           ebt_cleanup_entry, net, NULL);
1055
1056         vfree(table->entries);
1057         if (table->chainstack) {
1058                 for_each_possible_cpu(i)
1059                         vfree(table->chainstack[i]);
1060                 vfree(table->chainstack);
1061         }
1062         vfree(table);
1063
1064         vfree(counterstmp);
1065
1066 #ifdef CONFIG_AUDIT
1067         if (audit_enabled) {
1068                 audit_log(current->audit_context, GFP_KERNEL,
1069                           AUDIT_NETFILTER_CFG,
1070                           "table=%s family=%u entries=%u",
1071                           repl->name, AF_BRIDGE, repl->nentries);
1072         }
1073 #endif
1074         return ret;
1075
1076 free_unlock:
1077         mutex_unlock(&ebt_mutex);
1078 free_iterate:
1079         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1080                           ebt_cleanup_entry, net, NULL);
1081 free_counterstmp:
1082         vfree(counterstmp);
1083         /* can be initialized in translate_table() */
1084         if (newinfo->chainstack) {
1085                 for_each_possible_cpu(i)
1086                         vfree(newinfo->chainstack[i]);
1087                 vfree(newinfo->chainstack);
1088         }
1089         return ret;
1090 }
1091
1092 /* replace the table */
1093 static int do_replace(struct net *net, const void __user *user,
1094                       unsigned int len)
1095 {
1096         int ret, countersize;
1097         struct ebt_table_info *newinfo;
1098         struct ebt_replace tmp;
1099
1100         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1101                 return -EFAULT;
1102
1103         if (len != sizeof(tmp) + tmp.entries_size) {
1104                 BUGPRINT("Wrong len argument\n");
1105                 return -EINVAL;
1106         }
1107
1108         if (tmp.entries_size == 0) {
1109                 BUGPRINT("Entries_size never zero\n");
1110                 return -EINVAL;
1111         }
1112         /* overflow check */
1113         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1114                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1115                 return -ENOMEM;
1116         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1117                 return -ENOMEM;
1118
1119         tmp.name[sizeof(tmp.name) - 1] = 0;
1120
1121         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1122         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1123         if (!newinfo)
1124                 return -ENOMEM;
1125
1126         if (countersize)
1127                 memset(newinfo->counters, 0, countersize);
1128
1129         newinfo->entries = vmalloc(tmp.entries_size);
1130         if (!newinfo->entries) {
1131                 ret = -ENOMEM;
1132                 goto free_newinfo;
1133         }
1134         if (copy_from_user(
1135            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1136                 BUGPRINT("Couldn't copy entries from userspace\n");
1137                 ret = -EFAULT;
1138                 goto free_entries;
1139         }
1140
1141         ret = do_replace_finish(net, &tmp, newinfo);
1142         if (ret == 0)
1143                 return ret;
1144 free_entries:
1145         vfree(newinfo->entries);
1146 free_newinfo:
1147         vfree(newinfo);
1148         return ret;
1149 }
1150
1151 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1152 {
1153         int i;
1154
1155         mutex_lock(&ebt_mutex);
1156         list_del(&table->list);
1157         mutex_unlock(&ebt_mutex);
1158         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1159                           ebt_cleanup_entry, net, NULL);
1160         if (table->private->nentries)
1161                 module_put(table->me);
1162         vfree(table->private->entries);
1163         if (table->private->chainstack) {
1164                 for_each_possible_cpu(i)
1165                         vfree(table->private->chainstack[i]);
1166                 vfree(table->private->chainstack);
1167         }
1168         vfree(table->private);
1169         kfree(table);
1170 }
1171
1172 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1173                        const struct nf_hook_ops *ops, struct ebt_table **res)
1174 {
1175         struct ebt_table_info *newinfo;
1176         struct ebt_table *t, *table;
1177         struct ebt_replace_kernel *repl;
1178         int ret, i, countersize;
1179         void *p;
1180
1181         if (input_table == NULL || (repl = input_table->table) == NULL ||
1182             repl->entries == NULL || repl->entries_size == 0 ||
1183             repl->counters != NULL || input_table->private != NULL) {
1184                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1185                 return -EINVAL;
1186         }
1187
1188         /* Don't add one table to multiple lists. */
1189         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1190         if (!table) {
1191                 ret = -ENOMEM;
1192                 goto out;
1193         }
1194
1195         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1196         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1197         ret = -ENOMEM;
1198         if (!newinfo)
1199                 goto free_table;
1200
1201         p = vmalloc(repl->entries_size);
1202         if (!p)
1203                 goto free_newinfo;
1204
1205         memcpy(p, repl->entries, repl->entries_size);
1206         newinfo->entries = p;
1207
1208         newinfo->entries_size = repl->entries_size;
1209         newinfo->nentries = repl->nentries;
1210
1211         if (countersize)
1212                 memset(newinfo->counters, 0, countersize);
1213
1214         /* fill in newinfo and parse the entries */
1215         newinfo->chainstack = NULL;
1216         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1217                 if ((repl->valid_hooks & (1 << i)) == 0)
1218                         newinfo->hook_entry[i] = NULL;
1219                 else
1220                         newinfo->hook_entry[i] = p +
1221                                 ((char *)repl->hook_entry[i] - repl->entries);
1222         }
1223         ret = translate_table(net, repl->name, newinfo);
1224         if (ret != 0) {
1225                 BUGPRINT("Translate_table failed\n");
1226                 goto free_chainstack;
1227         }
1228
1229         if (table->check && table->check(newinfo, table->valid_hooks)) {
1230                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1231                 ret = -EINVAL;
1232                 goto free_chainstack;
1233         }
1234
1235         table->private = newinfo;
1236         rwlock_init(&table->lock);
1237         mutex_lock(&ebt_mutex);
1238         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1239                 if (strcmp(t->name, table->name) == 0) {
1240                         ret = -EEXIST;
1241                         BUGPRINT("Table name already exists\n");
1242                         goto free_unlock;
1243                 }
1244         }
1245
1246         /* Hold a reference count if the chains aren't empty */
1247         if (newinfo->nentries && !try_module_get(table->me)) {
1248                 ret = -ENOENT;
1249                 goto free_unlock;
1250         }
1251         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1252         mutex_unlock(&ebt_mutex);
1253
1254         WRITE_ONCE(*res, table);
1255
1256         if (!ops)
1257                 return 0;
1258
1259         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1260         if (ret) {
1261                 __ebt_unregister_table(net, table);
1262                 *res = NULL;
1263         }
1264
1265         return ret;
1266 free_unlock:
1267         mutex_unlock(&ebt_mutex);
1268 free_chainstack:
1269         if (newinfo->chainstack) {
1270                 for_each_possible_cpu(i)
1271                         vfree(newinfo->chainstack[i]);
1272                 vfree(newinfo->chainstack);
1273         }
1274         vfree(newinfo->entries);
1275 free_newinfo:
1276         vfree(newinfo);
1277 free_table:
1278         kfree(table);
1279 out:
1280         return ret;
1281 }
1282
1283 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1284                           const struct nf_hook_ops *ops)
1285 {
1286         if (ops)
1287                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1288         __ebt_unregister_table(net, table);
1289 }
1290
1291 /* userspace just supplied us with counters */
1292 static int do_update_counters(struct net *net, const char *name,
1293                                 struct ebt_counter __user *counters,
1294                                 unsigned int num_counters,
1295                                 const void __user *user, unsigned int len)
1296 {
1297         int i, ret;
1298         struct ebt_counter *tmp;
1299         struct ebt_table *t;
1300
1301         if (num_counters == 0)
1302                 return -EINVAL;
1303
1304         tmp = vmalloc(num_counters * sizeof(*tmp));
1305         if (!tmp)
1306                 return -ENOMEM;
1307
1308         t = find_table_lock(net, name, &ret, &ebt_mutex);
1309         if (!t)
1310                 goto free_tmp;
1311
1312         if (num_counters != t->private->nentries) {
1313                 BUGPRINT("Wrong nr of counters\n");
1314                 ret = -EINVAL;
1315                 goto unlock_mutex;
1316         }
1317
1318         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1319                 ret = -EFAULT;
1320                 goto unlock_mutex;
1321         }
1322
1323         /* we want an atomic add of the counters */
1324         write_lock_bh(&t->lock);
1325
1326         /* we add to the counters of the first cpu */
1327         for (i = 0; i < num_counters; i++) {
1328                 t->private->counters[i].pcnt += tmp[i].pcnt;
1329                 t->private->counters[i].bcnt += tmp[i].bcnt;
1330         }
1331
1332         write_unlock_bh(&t->lock);
1333         ret = 0;
1334 unlock_mutex:
1335         mutex_unlock(&ebt_mutex);
1336 free_tmp:
1337         vfree(tmp);
1338         return ret;
1339 }
1340
1341 static int update_counters(struct net *net, const void __user *user,
1342                             unsigned int len)
1343 {
1344         struct ebt_replace hlp;
1345
1346         if (copy_from_user(&hlp, user, sizeof(hlp)))
1347                 return -EFAULT;
1348
1349         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1350                 return -EINVAL;
1351
1352         return do_update_counters(net, hlp.name, hlp.counters,
1353                                 hlp.num_counters, user, len);
1354 }
1355
1356 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1357                                   const char *data, int entrysize,
1358                                   int usersize, int datasize)
1359 {
1360         char name[EBT_FUNCTION_MAXNAMELEN] = {0};
1361
1362         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1363          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1364          */
1365         strlcpy(name, _name, sizeof(name));
1366         if (copy_to_user(um, name, EBT_FUNCTION_MAXNAMELEN) ||
1367             put_user(datasize, (int __user *)(um + EBT_FUNCTION_MAXNAMELEN)) ||
1368             xt_data_to_user(um + entrysize, data, usersize, datasize,
1369                             XT_ALIGN(datasize)))
1370                 return -EFAULT;
1371
1372         return 0;
1373 }
1374
1375 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1376                                     const char *base, char __user *ubase)
1377 {
1378         return ebt_obj_to_user(ubase + ((char *)m - base),
1379                                m->u.match->name, m->data, sizeof(*m),
1380                                m->u.match->usersize, m->match_size);
1381 }
1382
1383 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1384                                       const char *base, char __user *ubase)
1385 {
1386         return ebt_obj_to_user(ubase + ((char *)w - base),
1387                                w->u.watcher->name, w->data, sizeof(*w),
1388                                w->u.watcher->usersize, w->watcher_size);
1389 }
1390
1391 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1392                                     char __user *ubase)
1393 {
1394         int ret;
1395         char __user *hlp;
1396         const struct ebt_entry_target *t;
1397
1398         if (e->bitmask == 0) {
1399                 /* special case !EBT_ENTRY_OR_ENTRIES */
1400                 if (copy_to_user(ubase + ((char *)e - base), e,
1401                                  sizeof(struct ebt_entries)))
1402                         return -EFAULT;
1403                 return 0;
1404         }
1405
1406         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1407                 return -EFAULT;
1408
1409         hlp = ubase + (((char *)e + e->target_offset) - base);
1410         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1411
1412         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1413         if (ret != 0)
1414                 return ret;
1415         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1416         if (ret != 0)
1417                 return ret;
1418         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1419                               t->u.target->usersize, t->target_size);
1420         if (ret != 0)
1421                 return ret;
1422
1423         return 0;
1424 }
1425
1426 static int copy_counters_to_user(struct ebt_table *t,
1427                                  const struct ebt_counter *oldcounters,
1428                                  void __user *user, unsigned int num_counters,
1429                                  unsigned int nentries)
1430 {
1431         struct ebt_counter *counterstmp;
1432         int ret = 0;
1433
1434         /* userspace might not need the counters */
1435         if (num_counters == 0)
1436                 return 0;
1437
1438         if (num_counters != nentries) {
1439                 BUGPRINT("Num_counters wrong\n");
1440                 return -EINVAL;
1441         }
1442
1443         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1444         if (!counterstmp)
1445                 return -ENOMEM;
1446
1447         write_lock_bh(&t->lock);
1448         get_counters(oldcounters, counterstmp, nentries);
1449         write_unlock_bh(&t->lock);
1450
1451         if (copy_to_user(user, counterstmp,
1452            nentries * sizeof(struct ebt_counter)))
1453                 ret = -EFAULT;
1454         vfree(counterstmp);
1455         return ret;
1456 }
1457
1458 /* called with ebt_mutex locked */
1459 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1460                                    const int *len, int cmd)
1461 {
1462         struct ebt_replace tmp;
1463         const struct ebt_counter *oldcounters;
1464         unsigned int entries_size, nentries;
1465         int ret;
1466         char *entries;
1467
1468         if (cmd == EBT_SO_GET_ENTRIES) {
1469                 entries_size = t->private->entries_size;
1470                 nentries = t->private->nentries;
1471                 entries = t->private->entries;
1472                 oldcounters = t->private->counters;
1473         } else {
1474                 entries_size = t->table->entries_size;
1475                 nentries = t->table->nentries;
1476                 entries = t->table->entries;
1477                 oldcounters = t->table->counters;
1478         }
1479
1480         if (copy_from_user(&tmp, user, sizeof(tmp)))
1481                 return -EFAULT;
1482
1483         if (*len != sizeof(struct ebt_replace) + entries_size +
1484            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1485                 return -EINVAL;
1486
1487         if (tmp.nentries != nentries) {
1488                 BUGPRINT("Nentries wrong\n");
1489                 return -EINVAL;
1490         }
1491
1492         if (tmp.entries_size != entries_size) {
1493                 BUGPRINT("Wrong size\n");
1494                 return -EINVAL;
1495         }
1496
1497         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1498                                         tmp.num_counters, nentries);
1499         if (ret)
1500                 return ret;
1501
1502         /* set the match/watcher/target names right */
1503         return EBT_ENTRY_ITERATE(entries, entries_size,
1504            ebt_entry_to_user, entries, tmp.entries);
1505 }
1506
1507 static int do_ebt_set_ctl(struct sock *sk,
1508         int cmd, void __user *user, unsigned int len)
1509 {
1510         int ret;
1511         struct net *net = sock_net(sk);
1512
1513         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1514                 return -EPERM;
1515
1516         switch (cmd) {
1517         case EBT_SO_SET_ENTRIES:
1518                 ret = do_replace(net, user, len);
1519                 break;
1520         case EBT_SO_SET_COUNTERS:
1521                 ret = update_counters(net, user, len);
1522                 break;
1523         default:
1524                 ret = -EINVAL;
1525         }
1526         return ret;
1527 }
1528
1529 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1530 {
1531         int ret;
1532         struct ebt_replace tmp;
1533         struct ebt_table *t;
1534         struct net *net = sock_net(sk);
1535
1536         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1537                 return -EPERM;
1538
1539         if (copy_from_user(&tmp, user, sizeof(tmp)))
1540                 return -EFAULT;
1541
1542         tmp.name[sizeof(tmp.name) - 1] = '\0';
1543
1544         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1545         if (!t)
1546                 return ret;
1547
1548         switch (cmd) {
1549         case EBT_SO_GET_INFO:
1550         case EBT_SO_GET_INIT_INFO:
1551                 if (*len != sizeof(struct ebt_replace)) {
1552                         ret = -EINVAL;
1553                         mutex_unlock(&ebt_mutex);
1554                         break;
1555                 }
1556                 if (cmd == EBT_SO_GET_INFO) {
1557                         tmp.nentries = t->private->nentries;
1558                         tmp.entries_size = t->private->entries_size;
1559                         tmp.valid_hooks = t->valid_hooks;
1560                 } else {
1561                         tmp.nentries = t->table->nentries;
1562                         tmp.entries_size = t->table->entries_size;
1563                         tmp.valid_hooks = t->table->valid_hooks;
1564                 }
1565                 mutex_unlock(&ebt_mutex);
1566                 if (copy_to_user(user, &tmp, *len) != 0) {
1567                         BUGPRINT("c2u Didn't work\n");
1568                         ret = -EFAULT;
1569                         break;
1570                 }
1571                 ret = 0;
1572                 break;
1573
1574         case EBT_SO_GET_ENTRIES:
1575         case EBT_SO_GET_INIT_ENTRIES:
1576                 ret = copy_everything_to_user(t, user, len, cmd);
1577                 mutex_unlock(&ebt_mutex);
1578                 break;
1579
1580         default:
1581                 mutex_unlock(&ebt_mutex);
1582                 ret = -EINVAL;
1583         }
1584
1585         return ret;
1586 }
1587
1588 #ifdef CONFIG_COMPAT
1589 /* 32 bit-userspace compatibility definitions. */
1590 struct compat_ebt_replace {
1591         char name[EBT_TABLE_MAXNAMELEN];
1592         compat_uint_t valid_hooks;
1593         compat_uint_t nentries;
1594         compat_uint_t entries_size;
1595         /* start of the chains */
1596         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1597         /* nr of counters userspace expects back */
1598         compat_uint_t num_counters;
1599         /* where the kernel will put the old counters. */
1600         compat_uptr_t counters;
1601         compat_uptr_t entries;
1602 };
1603
1604 /* struct ebt_entry_match, _target and _watcher have same layout */
1605 struct compat_ebt_entry_mwt {
1606         union {
1607                 char name[EBT_FUNCTION_MAXNAMELEN];
1608                 compat_uptr_t ptr;
1609         } u;
1610         compat_uint_t match_size;
1611         compat_uint_t data[0];
1612 };
1613
1614 /* account for possible padding between match_size and ->data */
1615 static int ebt_compat_entry_padsize(void)
1616 {
1617         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1618                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1619         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1620                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1621 }
1622
1623 static int ebt_compat_match_offset(const struct xt_match *match,
1624                                    unsigned int userlen)
1625 {
1626         /* ebt_among needs special handling. The kernel .matchsize is
1627          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1628          * value is expected.
1629          * Example: userspace sends 4500, ebt_among.c wants 4504.
1630          */
1631         if (unlikely(match->matchsize == -1))
1632                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1633         return xt_compat_match_offset(match);
1634 }
1635
1636 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1637                                 unsigned int *size)
1638 {
1639         const struct xt_match *match = m->u.match;
1640         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1641         int off = ebt_compat_match_offset(match, m->match_size);
1642         compat_uint_t msize = m->match_size - off;
1643
1644         BUG_ON(off >= m->match_size);
1645
1646         if (copy_to_user(cm->u.name, match->name,
1647             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1648                 return -EFAULT;
1649
1650         if (match->compat_to_user) {
1651                 if (match->compat_to_user(cm->data, m->data))
1652                         return -EFAULT;
1653         } else {
1654                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1655                                     COMPAT_XT_ALIGN(msize)))
1656                         return -EFAULT;
1657         }
1658
1659         *size -= ebt_compat_entry_padsize() + off;
1660         *dstptr = cm->data;
1661         *dstptr += msize;
1662         return 0;
1663 }
1664
1665 static int compat_target_to_user(struct ebt_entry_target *t,
1666                                  void __user **dstptr,
1667                                  unsigned int *size)
1668 {
1669         const struct xt_target *target = t->u.target;
1670         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1671         int off = xt_compat_target_offset(target);
1672         compat_uint_t tsize = t->target_size - off;
1673
1674         BUG_ON(off >= t->target_size);
1675
1676         if (copy_to_user(cm->u.name, target->name,
1677             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1678                 return -EFAULT;
1679
1680         if (target->compat_to_user) {
1681                 if (target->compat_to_user(cm->data, t->data))
1682                         return -EFAULT;
1683         } else {
1684                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1685                                     COMPAT_XT_ALIGN(tsize)))
1686                         return -EFAULT;
1687         }
1688
1689         *size -= ebt_compat_entry_padsize() + off;
1690         *dstptr = cm->data;
1691         *dstptr += tsize;
1692         return 0;
1693 }
1694
1695 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1696                                   void __user **dstptr,
1697                                   unsigned int *size)
1698 {
1699         return compat_target_to_user((struct ebt_entry_target *)w,
1700                                                         dstptr, size);
1701 }
1702
1703 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1704                                 unsigned int *size)
1705 {
1706         struct ebt_entry_target *t;
1707         struct ebt_entry __user *ce;
1708         u32 watchers_offset, target_offset, next_offset;
1709         compat_uint_t origsize;
1710         int ret;
1711
1712         if (e->bitmask == 0) {
1713                 if (*size < sizeof(struct ebt_entries))
1714                         return -EINVAL;
1715                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1716                         return -EFAULT;
1717
1718                 *dstptr += sizeof(struct ebt_entries);
1719                 *size -= sizeof(struct ebt_entries);
1720                 return 0;
1721         }
1722
1723         if (*size < sizeof(*ce))
1724                 return -EINVAL;
1725
1726         ce = *dstptr;
1727         if (copy_to_user(ce, e, sizeof(*ce)))
1728                 return -EFAULT;
1729
1730         origsize = *size;
1731         *dstptr += sizeof(*ce);
1732
1733         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1734         if (ret)
1735                 return ret;
1736         watchers_offset = e->watchers_offset - (origsize - *size);
1737
1738         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1739         if (ret)
1740                 return ret;
1741         target_offset = e->target_offset - (origsize - *size);
1742
1743         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1744
1745         ret = compat_target_to_user(t, dstptr, size);
1746         if (ret)
1747                 return ret;
1748         next_offset = e->next_offset - (origsize - *size);
1749
1750         if (put_user(watchers_offset, &ce->watchers_offset) ||
1751             put_user(target_offset, &ce->target_offset) ||
1752             put_user(next_offset, &ce->next_offset))
1753                 return -EFAULT;
1754
1755         *size -= sizeof(*ce);
1756         return 0;
1757 }
1758
1759 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1760 {
1761         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1762         *off += ebt_compat_entry_padsize();
1763         return 0;
1764 }
1765
1766 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1767 {
1768         *off += xt_compat_target_offset(w->u.watcher);
1769         *off += ebt_compat_entry_padsize();
1770         return 0;
1771 }
1772
1773 static int compat_calc_entry(const struct ebt_entry *e,
1774                              const struct ebt_table_info *info,
1775                              const void *base,
1776                              struct compat_ebt_replace *newinfo)
1777 {
1778         const struct ebt_entry_target *t;
1779         unsigned int entry_offset;
1780         int off, ret, i;
1781
1782         if (e->bitmask == 0)
1783                 return 0;
1784
1785         off = 0;
1786         entry_offset = (void *)e - base;
1787
1788         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1789         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1790
1791         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1792
1793         off += xt_compat_target_offset(t->u.target);
1794         off += ebt_compat_entry_padsize();
1795
1796         newinfo->entries_size -= off;
1797
1798         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1799         if (ret)
1800                 return ret;
1801
1802         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1803                 const void *hookptr = info->hook_entry[i];
1804                 if (info->hook_entry[i] &&
1805                     (e < (struct ebt_entry *)(base - hookptr))) {
1806                         newinfo->hook_entry[i] -= off;
1807                         pr_debug("0x%08X -> 0x%08X\n",
1808                                         newinfo->hook_entry[i] + off,
1809                                         newinfo->hook_entry[i]);
1810                 }
1811         }
1812
1813         return 0;
1814 }
1815
1816
1817 static int compat_table_info(const struct ebt_table_info *info,
1818                              struct compat_ebt_replace *newinfo)
1819 {
1820         unsigned int size = info->entries_size;
1821         const void *entries = info->entries;
1822
1823         newinfo->entries_size = size;
1824
1825         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1826         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1827                                                         entries, newinfo);
1828 }
1829
1830 static int compat_copy_everything_to_user(struct ebt_table *t,
1831                                           void __user *user, int *len, int cmd)
1832 {
1833         struct compat_ebt_replace repl, tmp;
1834         struct ebt_counter *oldcounters;
1835         struct ebt_table_info tinfo;
1836         int ret;
1837         void __user *pos;
1838
1839         memset(&tinfo, 0, sizeof(tinfo));
1840
1841         if (cmd == EBT_SO_GET_ENTRIES) {
1842                 tinfo.entries_size = t->private->entries_size;
1843                 tinfo.nentries = t->private->nentries;
1844                 tinfo.entries = t->private->entries;
1845                 oldcounters = t->private->counters;
1846         } else {
1847                 tinfo.entries_size = t->table->entries_size;
1848                 tinfo.nentries = t->table->nentries;
1849                 tinfo.entries = t->table->entries;
1850                 oldcounters = t->table->counters;
1851         }
1852
1853         if (copy_from_user(&tmp, user, sizeof(tmp)))
1854                 return -EFAULT;
1855
1856         if (tmp.nentries != tinfo.nentries ||
1857            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1858                 return -EINVAL;
1859
1860         memcpy(&repl, &tmp, sizeof(repl));
1861         if (cmd == EBT_SO_GET_ENTRIES)
1862                 ret = compat_table_info(t->private, &repl);
1863         else
1864                 ret = compat_table_info(&tinfo, &repl);
1865         if (ret)
1866                 return ret;
1867
1868         if (*len != sizeof(tmp) + repl.entries_size +
1869            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1870                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1871                                 *len, tinfo.entries_size, repl.entries_size);
1872                 return -EINVAL;
1873         }
1874
1875         /* userspace might not need the counters */
1876         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1877                                         tmp.num_counters, tinfo.nentries);
1878         if (ret)
1879                 return ret;
1880
1881         pos = compat_ptr(tmp.entries);
1882         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1883                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1884 }
1885
1886 struct ebt_entries_buf_state {
1887         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1888         u32 buf_kern_len;       /* total size of kernel buffer */
1889         u32 buf_kern_offset;    /* amount of data copied so far */
1890         u32 buf_user_offset;    /* read position in userspace buffer */
1891 };
1892
1893 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1894 {
1895         state->buf_kern_offset += sz;
1896         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1897 }
1898
1899 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1900                        void *data, unsigned int sz)
1901 {
1902         if (state->buf_kern_start == NULL)
1903                 goto count_only;
1904
1905         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1906
1907         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1908
1909  count_only:
1910         state->buf_user_offset += sz;
1911         return ebt_buf_count(state, sz);
1912 }
1913
1914 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1915 {
1916         char *b = state->buf_kern_start;
1917
1918         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1919
1920         if (b != NULL && sz > 0)
1921                 memset(b + state->buf_kern_offset, 0, sz);
1922         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1923         return ebt_buf_count(state, sz);
1924 }
1925
1926 enum compat_mwt {
1927         EBT_COMPAT_MATCH,
1928         EBT_COMPAT_WATCHER,
1929         EBT_COMPAT_TARGET,
1930 };
1931
1932 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1933                                 enum compat_mwt compat_mwt,
1934                                 struct ebt_entries_buf_state *state,
1935                                 const unsigned char *base)
1936 {
1937         char name[EBT_FUNCTION_MAXNAMELEN];
1938         struct xt_match *match;
1939         struct xt_target *wt;
1940         void *dst = NULL;
1941         int off, pad = 0;
1942         unsigned int size_kern, match_size = mwt->match_size;
1943
1944         strlcpy(name, mwt->u.name, sizeof(name));
1945
1946         if (state->buf_kern_start)
1947                 dst = state->buf_kern_start + state->buf_kern_offset;
1948
1949         switch (compat_mwt) {
1950         case EBT_COMPAT_MATCH:
1951                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1952                 if (IS_ERR(match))
1953                         return PTR_ERR(match);
1954
1955                 off = ebt_compat_match_offset(match, match_size);
1956                 if (dst) {
1957                         if (match->compat_from_user)
1958                                 match->compat_from_user(dst, mwt->data);
1959                         else
1960                                 memcpy(dst, mwt->data, match_size);
1961                 }
1962
1963                 size_kern = match->matchsize;
1964                 if (unlikely(size_kern == -1))
1965                         size_kern = match_size;
1966                 module_put(match->me);
1967                 break;
1968         case EBT_COMPAT_WATCHER: /* fallthrough */
1969         case EBT_COMPAT_TARGET:
1970                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1971                 if (IS_ERR(wt))
1972                         return PTR_ERR(wt);
1973                 off = xt_compat_target_offset(wt);
1974
1975                 if (dst) {
1976                         if (wt->compat_from_user)
1977                                 wt->compat_from_user(dst, mwt->data);
1978                         else
1979                                 memcpy(dst, mwt->data, match_size);
1980                 }
1981
1982                 size_kern = wt->targetsize;
1983                 module_put(wt->me);
1984                 break;
1985
1986         default:
1987                 return -EINVAL;
1988         }
1989
1990         state->buf_kern_offset += match_size + off;
1991         state->buf_user_offset += match_size;
1992         pad = XT_ALIGN(size_kern) - size_kern;
1993
1994         if (pad > 0 && dst) {
1995                 BUG_ON(state->buf_kern_len <= pad);
1996                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1997                 memset(dst + size_kern, 0, pad);
1998         }
1999         return off + match_size;
2000 }
2001
2002 /* return size of all matches, watchers or target, including necessary
2003  * alignment and padding.
2004  */
2005 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2006                         unsigned int size_left, enum compat_mwt type,
2007                         struct ebt_entries_buf_state *state, const void *base)
2008 {
2009         int growth = 0;
2010         char *buf;
2011
2012         if (size_left == 0)
2013                 return 0;
2014
2015         buf = (char *) match32;
2016
2017         while (size_left >= sizeof(*match32)) {
2018                 struct ebt_entry_match *match_kern;
2019                 int ret;
2020
2021                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2022                 if (match_kern) {
2023                         char *tmp;
2024                         tmp = state->buf_kern_start + state->buf_kern_offset;
2025                         match_kern = (struct ebt_entry_match *) tmp;
2026                 }
2027                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2028                 if (ret < 0)
2029                         return ret;
2030                 size_left -= sizeof(*match32);
2031
2032                 /* add padding before match->data (if any) */
2033                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2034                 if (ret < 0)
2035                         return ret;
2036
2037                 if (match32->match_size > size_left)
2038                         return -EINVAL;
2039
2040                 size_left -= match32->match_size;
2041
2042                 ret = compat_mtw_from_user(match32, type, state, base);
2043                 if (ret < 0)
2044                         return ret;
2045
2046                 BUG_ON(ret < match32->match_size);
2047                 growth += ret - match32->match_size;
2048                 growth += ebt_compat_entry_padsize();
2049
2050                 buf += sizeof(*match32);
2051                 buf += match32->match_size;
2052
2053                 if (match_kern)
2054                         match_kern->match_size = ret;
2055
2056                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2057                 match32 = (struct compat_ebt_entry_mwt *) buf;
2058         }
2059
2060         return growth;
2061 }
2062
2063 /* called for all ebt_entry structures. */
2064 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2065                           unsigned int *total,
2066                           struct ebt_entries_buf_state *state)
2067 {
2068         unsigned int i, j, startoff, new_offset = 0;
2069         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2070         unsigned int offsets[4];
2071         unsigned int *offsets_update = NULL;
2072         int ret;
2073         char *buf_start;
2074
2075         if (*total < sizeof(struct ebt_entries))
2076                 return -EINVAL;
2077
2078         if (!entry->bitmask) {
2079                 *total -= sizeof(struct ebt_entries);
2080                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2081         }
2082         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2083                 return -EINVAL;
2084
2085         startoff = state->buf_user_offset;
2086         /* pull in most part of ebt_entry, it does not need to be changed. */
2087         ret = ebt_buf_add(state, entry,
2088                         offsetof(struct ebt_entry, watchers_offset));
2089         if (ret < 0)
2090                 return ret;
2091
2092         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2093         memcpy(&offsets[1], &entry->watchers_offset,
2094                         sizeof(offsets) - sizeof(offsets[0]));
2095
2096         if (state->buf_kern_start) {
2097                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2098                 offsets_update = (unsigned int *) buf_start;
2099         }
2100         ret = ebt_buf_add(state, &offsets[1],
2101                         sizeof(offsets) - sizeof(offsets[0]));
2102         if (ret < 0)
2103                 return ret;
2104         buf_start = (char *) entry;
2105         /* 0: matches offset, always follows ebt_entry.
2106          * 1: watchers offset, from ebt_entry structure
2107          * 2: target offset, from ebt_entry structure
2108          * 3: next ebt_entry offset, from ebt_entry structure
2109          *
2110          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2111          */
2112         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2113                 struct compat_ebt_entry_mwt *match32;
2114                 unsigned int size;
2115                 char *buf = buf_start;
2116
2117                 buf = buf_start + offsets[i];
2118                 if (offsets[i] > offsets[j])
2119                         return -EINVAL;
2120
2121                 match32 = (struct compat_ebt_entry_mwt *) buf;
2122                 size = offsets[j] - offsets[i];
2123                 ret = ebt_size_mwt(match32, size, i, state, base);
2124                 if (ret < 0)
2125                         return ret;
2126                 new_offset += ret;
2127                 if (offsets_update && new_offset) {
2128                         pr_debug("change offset %d to %d\n",
2129                                 offsets_update[i], offsets[j] + new_offset);
2130                         offsets_update[i] = offsets[j] + new_offset;
2131                 }
2132         }
2133
2134         if (state->buf_kern_start == NULL) {
2135                 unsigned int offset = buf_start - (char *) base;
2136
2137                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2138                 if (ret < 0)
2139                         return ret;
2140         }
2141
2142         startoff = state->buf_user_offset - startoff;
2143
2144         BUG_ON(*total < startoff);
2145         *total -= startoff;
2146         return 0;
2147 }
2148
2149 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2150  * It might need more memory when copied to a 64 bit kernel in case
2151  * userspace is 32-bit. So, first task: find out how much memory is needed.
2152  *
2153  * Called before validation is performed.
2154  */
2155 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2156                                 struct ebt_entries_buf_state *state)
2157 {
2158         unsigned int size_remaining = size_user;
2159         int ret;
2160
2161         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2162                                         &size_remaining, state);
2163         if (ret < 0)
2164                 return ret;
2165
2166         WARN_ON(size_remaining);
2167         return state->buf_kern_offset;
2168 }
2169
2170
2171 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2172                                             void __user *user, unsigned int len)
2173 {
2174         struct compat_ebt_replace tmp;
2175         int i;
2176
2177         if (len < sizeof(tmp))
2178                 return -EINVAL;
2179
2180         if (copy_from_user(&tmp, user, sizeof(tmp)))
2181                 return -EFAULT;
2182
2183         if (len != sizeof(tmp) + tmp.entries_size)
2184                 return -EINVAL;
2185
2186         if (tmp.entries_size == 0)
2187                 return -EINVAL;
2188
2189         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2190                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2191                 return -ENOMEM;
2192         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2193                 return -ENOMEM;
2194
2195         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2196
2197         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2198         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2199                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2200
2201         repl->num_counters = tmp.num_counters;
2202         repl->counters = compat_ptr(tmp.counters);
2203         repl->entries = compat_ptr(tmp.entries);
2204         return 0;
2205 }
2206
2207 static int compat_do_replace(struct net *net, void __user *user,
2208                              unsigned int len)
2209 {
2210         int ret, i, countersize, size64;
2211         struct ebt_table_info *newinfo;
2212         struct ebt_replace tmp;
2213         struct ebt_entries_buf_state state;
2214         void *entries_tmp;
2215
2216         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2217         if (ret) {
2218                 /* try real handler in case userland supplied needed padding */
2219                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2220                         ret = 0;
2221                 return ret;
2222         }
2223
2224         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2225         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2226         if (!newinfo)
2227                 return -ENOMEM;
2228
2229         if (countersize)
2230                 memset(newinfo->counters, 0, countersize);
2231
2232         memset(&state, 0, sizeof(state));
2233
2234         newinfo->entries = vmalloc(tmp.entries_size);
2235         if (!newinfo->entries) {
2236                 ret = -ENOMEM;
2237                 goto free_newinfo;
2238         }
2239         if (copy_from_user(
2240            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2241                 ret = -EFAULT;
2242                 goto free_entries;
2243         }
2244
2245         entries_tmp = newinfo->entries;
2246
2247         xt_compat_lock(NFPROTO_BRIDGE);
2248
2249         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2250         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2251         if (ret < 0)
2252                 goto out_unlock;
2253
2254         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2255                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2256                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2257
2258         size64 = ret;
2259         newinfo->entries = vmalloc(size64);
2260         if (!newinfo->entries) {
2261                 vfree(entries_tmp);
2262                 ret = -ENOMEM;
2263                 goto out_unlock;
2264         }
2265
2266         memset(&state, 0, sizeof(state));
2267         state.buf_kern_start = newinfo->entries;
2268         state.buf_kern_len = size64;
2269
2270         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2271         BUG_ON(ret < 0);        /* parses same data again */
2272
2273         vfree(entries_tmp);
2274         tmp.entries_size = size64;
2275
2276         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2277                 char __user *usrptr;
2278                 if (tmp.hook_entry[i]) {
2279                         unsigned int delta;
2280                         usrptr = (char __user *) tmp.hook_entry[i];
2281                         delta = usrptr - tmp.entries;
2282                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2283                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2284                 }
2285         }
2286
2287         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2288         xt_compat_unlock(NFPROTO_BRIDGE);
2289
2290         ret = do_replace_finish(net, &tmp, newinfo);
2291         if (ret == 0)
2292                 return ret;
2293 free_entries:
2294         vfree(newinfo->entries);
2295 free_newinfo:
2296         vfree(newinfo);
2297         return ret;
2298 out_unlock:
2299         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2300         xt_compat_unlock(NFPROTO_BRIDGE);
2301         goto free_entries;
2302 }
2303
2304 static int compat_update_counters(struct net *net, void __user *user,
2305                                   unsigned int len)
2306 {
2307         struct compat_ebt_replace hlp;
2308
2309         if (copy_from_user(&hlp, user, sizeof(hlp)))
2310                 return -EFAULT;
2311
2312         /* try real handler in case userland supplied needed padding */
2313         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2314                 return update_counters(net, user, len);
2315
2316         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2317                                         hlp.num_counters, user, len);
2318 }
2319
2320 static int compat_do_ebt_set_ctl(struct sock *sk,
2321                 int cmd, void __user *user, unsigned int len)
2322 {
2323         int ret;
2324         struct net *net = sock_net(sk);
2325
2326         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2327                 return -EPERM;
2328
2329         switch (cmd) {
2330         case EBT_SO_SET_ENTRIES:
2331                 ret = compat_do_replace(net, user, len);
2332                 break;
2333         case EBT_SO_SET_COUNTERS:
2334                 ret = compat_update_counters(net, user, len);
2335                 break;
2336         default:
2337                 ret = -EINVAL;
2338         }
2339         return ret;
2340 }
2341
2342 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2343                 void __user *user, int *len)
2344 {
2345         int ret;
2346         struct compat_ebt_replace tmp;
2347         struct ebt_table *t;
2348         struct net *net = sock_net(sk);
2349
2350         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2351                 return -EPERM;
2352
2353         /* try real handler in case userland supplied needed padding */
2354         if ((cmd == EBT_SO_GET_INFO ||
2355              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2356                         return do_ebt_get_ctl(sk, cmd, user, len);
2357
2358         if (copy_from_user(&tmp, user, sizeof(tmp)))
2359                 return -EFAULT;
2360
2361         tmp.name[sizeof(tmp.name) - 1] = '\0';
2362
2363         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2364         if (!t)
2365                 return ret;
2366
2367         xt_compat_lock(NFPROTO_BRIDGE);
2368         switch (cmd) {
2369         case EBT_SO_GET_INFO:
2370                 tmp.nentries = t->private->nentries;
2371                 ret = compat_table_info(t->private, &tmp);
2372                 if (ret)
2373                         goto out;
2374                 tmp.valid_hooks = t->valid_hooks;
2375
2376                 if (copy_to_user(user, &tmp, *len) != 0) {
2377                         ret = -EFAULT;
2378                         break;
2379                 }
2380                 ret = 0;
2381                 break;
2382         case EBT_SO_GET_INIT_INFO:
2383                 tmp.nentries = t->table->nentries;
2384                 tmp.entries_size = t->table->entries_size;
2385                 tmp.valid_hooks = t->table->valid_hooks;
2386
2387                 if (copy_to_user(user, &tmp, *len) != 0) {
2388                         ret = -EFAULT;
2389                         break;
2390                 }
2391                 ret = 0;
2392                 break;
2393         case EBT_SO_GET_ENTRIES:
2394         case EBT_SO_GET_INIT_ENTRIES:
2395                 /* try real handler first in case of userland-side padding.
2396                  * in case we are dealing with an 'ordinary' 32 bit binary
2397                  * without 64bit compatibility padding, this will fail right
2398                  * after copy_from_user when the *len argument is validated.
2399                  *
2400                  * the compat_ variant needs to do one pass over the kernel
2401                  * data set to adjust for size differences before it the check.
2402                  */
2403                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2404                         ret = 0;
2405                 else
2406                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2407                 break;
2408         default:
2409                 ret = -EINVAL;
2410         }
2411  out:
2412         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2413         xt_compat_unlock(NFPROTO_BRIDGE);
2414         mutex_unlock(&ebt_mutex);
2415         return ret;
2416 }
2417 #endif
2418
2419 static struct nf_sockopt_ops ebt_sockopts = {
2420         .pf             = PF_INET,
2421         .set_optmin     = EBT_BASE_CTL,
2422         .set_optmax     = EBT_SO_SET_MAX + 1,
2423         .set            = do_ebt_set_ctl,
2424 #ifdef CONFIG_COMPAT
2425         .compat_set     = compat_do_ebt_set_ctl,
2426 #endif
2427         .get_optmin     = EBT_BASE_CTL,
2428         .get_optmax     = EBT_SO_GET_MAX + 1,
2429         .get            = do_ebt_get_ctl,
2430 #ifdef CONFIG_COMPAT
2431         .compat_get     = compat_do_ebt_get_ctl,
2432 #endif
2433         .owner          = THIS_MODULE,
2434 };
2435
2436 static int __init ebtables_init(void)
2437 {
2438         int ret;
2439
2440         ret = xt_register_target(&ebt_standard_target);
2441         if (ret < 0)
2442                 return ret;
2443         ret = nf_register_sockopt(&ebt_sockopts);
2444         if (ret < 0) {
2445                 xt_unregister_target(&ebt_standard_target);
2446                 return ret;
2447         }
2448
2449         printk(KERN_INFO "Ebtables v2.0 registered\n");
2450         return 0;
2451 }
2452
2453 static void __exit ebtables_fini(void)
2454 {
2455         nf_unregister_sockopt(&ebt_sockopts);
2456         xt_unregister_target(&ebt_standard_target);
2457         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
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");