net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is strongly inspired by the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  37
  38 /* Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48                                  COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_action_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return !m->u.match->match(skb, par);
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 static inline const struct ebt_entry_target *
 181 ebt_get_target_c(const struct ebt_entry *e)
 182 {
 183         return ebt_get_target((struct ebt_entry *)e);
 184 }
 185
 186 /* Do some firewalling */
 187 unsigned int ebt_do_table(struct sk_buff *skb,
 188                           const struct nf_hook_state *state,
 189                           struct ebt_table *table)
 190 {
 191         unsigned int hook = state->hook;
 192         int i, nentries;
 193         struct ebt_entry *point;
 194         struct ebt_counter *counter_base, *cb_base;
 195         const struct ebt_entry_target *t;
 196         int verdict, sp = 0;
 197         struct ebt_chainstack *cs;
 198         struct ebt_entries *chaininfo;
 199         const char *base;
 200         const struct ebt_table_info *private;
 201         struct xt_action_param acpar;
 202
 203         acpar.state   = state;
 204         acpar.hotdrop = false;
 205
 206         read_lock_bh(&table->lock);
 207         private = table->private;
 208         cb_base = COUNTER_BASE(private->counters, private->nentries,
 209            smp_processor_id());
 210         if (private->chainstack)
 211                 cs = private->chainstack[smp_processor_id()];
 212         else
 213                 cs = NULL;
 214         chaininfo = private->hook_entry[hook];
 215         nentries = private->hook_entry[hook]->nentries;
 216         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 217         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 218         /* base for chain jumps */
 219         base = private->entries;
 220         i = 0;
 221         while (i < nentries) {
 222                 if (ebt_basic_match(point, skb, state->in, state->out))
 223                         goto letscontinue;
 224
 225                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 226                         goto letscontinue;
 227                 if (acpar.hotdrop) {
 228                         read_unlock_bh(&table->lock);
 229                         return NF_DROP;
 230                 }
 231
 232                 ADD_COUNTER(*(counter_base + i), 1, skb->len);
 233
 234                 /* these should only watch: not modify, nor tell us
 235                  * what to do with the packet
 236                  */
 237                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 238
 239                 t = ebt_get_target_c(point);
 240                 /* standard target */
 241                 if (!t->u.target->target)
 242                         verdict = ((struct ebt_standard_target *)t)->verdict;
 243                 else {
 244                         acpar.target   = t->u.target;
 245                         acpar.targinfo = t->data;
 246                         verdict = t->u.target->target(skb, &acpar);
 247                 }
 248                 if (verdict == EBT_ACCEPT) {
 249                         read_unlock_bh(&table->lock);
 250                         return NF_ACCEPT;
 251                 }
 252                 if (verdict == EBT_DROP) {
 253                         read_unlock_bh(&table->lock);
 254                         return NF_DROP;
 255                 }
 256                 if (verdict == EBT_RETURN) {
 257 letsreturn:
 258                         if (WARN(sp == 0, "RETURN on base chain")) {
 259                                 /* act like this is EBT_CONTINUE */
 260                                 goto letscontinue;
 261                         }
 262
 263                         sp--;
 264                         /* put all the local variables right */
 265                         i = cs[sp].n;
 266                         chaininfo = cs[sp].chaininfo;
 267                         nentries = chaininfo->nentries;
 268                         point = cs[sp].e;
 269                         counter_base = cb_base +
 270                            chaininfo->counter_offset;
 271                         continue;
 272                 }
 273                 if (verdict == EBT_CONTINUE)
 274                         goto letscontinue;
 275
 276                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 277                         read_unlock_bh(&table->lock);
 278                         return NF_DROP;
 279                 }
 280
 281                 /* jump to a udc */
 282                 cs[sp].n = i + 1;
 283                 cs[sp].chaininfo = chaininfo;
 284                 cs[sp].e = ebt_next_entry(point);
 285                 i = 0;
 286                 chaininfo = (struct ebt_entries *) (base + verdict);
 287
 288                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 289                         read_unlock_bh(&table->lock);
 290                         return NF_DROP;
 291                 }
 292
 293                 nentries = chaininfo->nentries;
 294                 point = (struct ebt_entry *)chaininfo->data;
 295                 counter_base = cb_base + chaininfo->counter_offset;
 296                 sp++;
 297                 continue;
 298 letscontinue:
 299                 point = ebt_next_entry(point);
 300                 i++;
 301         }
 302
 303         /* I actually like this :) */
 304         if (chaininfo->policy == EBT_RETURN)
 305                 goto letsreturn;
 306         if (chaininfo->policy == EBT_ACCEPT) {
 307                 read_unlock_bh(&table->lock);
 308                 return NF_ACCEPT;
 309         }
 310         read_unlock_bh(&table->lock);
 311         return NF_DROP;
 312 }
 313
 314 /* If it succeeds, returns element and locks mutex */
 315 static inline void *
 316 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 317                         struct mutex *mutex)
 318 {
 319         struct {
 320                 struct list_head list;
 321                 char name[EBT_FUNCTION_MAXNAMELEN];
 322         } *e;
 323
 324         mutex_lock(mutex);
 325         list_for_each_entry(e, head, list) {
 326                 if (strcmp(e->name, name) == 0)
 327                         return e;
 328         }
 329         *error = -ENOENT;
 330         mutex_unlock(mutex);
 331         return NULL;
 332 }
 333
 334 static void *
 335 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 336                  int *error, struct mutex *mutex)
 337 {
 338         return try_then_request_module(
 339                         find_inlist_lock_noload(head, name, error, mutex),
 340                         "%s%s", prefix, name);
 341 }
 342
 343 static inline struct ebt_table *
 344 find_table_lock(struct net *net, const char *name, int *error,
 345                 struct mutex *mutex)
 346 {
 347         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 348                                 "ebtable_", error, mutex);
 349 }
 350
 351 static inline void ebt_free_table_info(struct ebt_table_info *info)
 352 {
 353         int i;
 354
 355         if (info->chainstack) {
 356                 for_each_possible_cpu(i)
 357                         vfree(info->chainstack[i]);
 358                 vfree(info->chainstack);
 359         }
 360 }
 361 static inline int
 362 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 363                 unsigned int *cnt)
 364 {
 365         const struct ebt_entry *e = par->entryinfo;
 366         struct xt_match *match;
 367         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 368         int ret;
 369
 370         if (left < sizeof(struct ebt_entry_match) ||
 371             left - sizeof(struct ebt_entry_match) < m->match_size)
 372                 return -EINVAL;
 373
 374         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 375         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 376                 if (!IS_ERR(match))
 377                         module_put(match->me);
 378                 request_module("ebt_%s", m->u.name);
 379                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 380         }
 381         if (IS_ERR(match))
 382                 return PTR_ERR(match);
 383         m->u.match = match;
 384
 385         par->match     = match;
 386         par->matchinfo = m->data;
 387         ret = xt_check_match(par, m->match_size,
 388               e->ethproto, e->invflags & EBT_IPROTO);
 389         if (ret < 0) {
 390                 module_put(match->me);
 391                 return ret;
 392         }
 393
 394         (*cnt)++;
 395         return 0;
 396 }
 397
 398 static inline int
 399 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 400                   unsigned int *cnt)
 401 {
 402         const struct ebt_entry *e = par->entryinfo;
 403         struct xt_target *watcher;
 404         size_t left = ((char *)e + e->target_offset) - (char *)w;
 405         int ret;
 406
 407         if (left < sizeof(struct ebt_entry_watcher) ||
 408            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 409                 return -EINVAL;
 410
 411         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 412         if (IS_ERR(watcher))
 413                 return PTR_ERR(watcher);
 414
 415         if (watcher->family != NFPROTO_BRIDGE) {
 416                 module_put(watcher->me);
 417                 return -ENOENT;
 418         }
 419
 420         w->u.watcher = watcher;
 421
 422         par->target   = watcher;
 423         par->targinfo = w->data;
 424         ret = xt_check_target(par, w->watcher_size,
 425               e->ethproto, e->invflags & EBT_IPROTO);
 426         if (ret < 0) {
 427                 module_put(watcher->me);
 428                 return ret;
 429         }
 430
 431         (*cnt)++;
 432         return 0;
 433 }
 434
 435 static int ebt_verify_pointers(const struct ebt_replace *repl,
 436                                struct ebt_table_info *newinfo)
 437 {
 438         unsigned int limit = repl->entries_size;
 439         unsigned int valid_hooks = repl->valid_hooks;
 440         unsigned int offset = 0;
 441         int i;
 442
 443         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 444                 newinfo->hook_entry[i] = NULL;
 445
 446         newinfo->entries_size = repl->entries_size;
 447         newinfo->nentries = repl->nentries;
 448
 449         while (offset < limit) {
 450                 size_t left = limit - offset;
 451                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 452
 453                 if (left < sizeof(unsigned int))
 454                         break;
 455
 456                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 457                         if ((valid_hooks & (1 << i)) == 0)
 458                                 continue;
 459                         if ((char __user *)repl->hook_entry[i] ==
 460                              repl->entries + offset)
 461                                 break;
 462                 }
 463
 464                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 465                         if (e->bitmask != 0) {
 466                                 /* we make userspace set this right,
 467                                  * so there is no misunderstanding
 468                                  */
 469                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 470                                          "in distinguisher\n");
 471                                 return -EINVAL;
 472                         }
 473                         if (i != NF_BR_NUMHOOKS)
 474                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 475                         if (left < sizeof(struct ebt_entries))
 476                                 break;
 477                         offset += sizeof(struct ebt_entries);
 478                 } else {
 479                         if (left < sizeof(struct ebt_entry))
 480                                 break;
 481                         if (left < e->next_offset)
 482                                 break;
 483                         if (e->next_offset < sizeof(struct ebt_entry))
 484                                 return -EINVAL;
 485                         offset += e->next_offset;
 486                 }
 487         }
 488         if (offset != limit) {
 489                 BUGPRINT("entries_size too small\n");
 490                 return -EINVAL;
 491         }
 492
 493         /* check if all valid hooks have a chain */
 494         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 495                 if (!newinfo->hook_entry[i] &&
 496                    (valid_hooks & (1 << i))) {
 497                         BUGPRINT("Valid hook without chain\n");
 498                         return -EINVAL;
 499                 }
 500         }
 501         return 0;
 502 }
 503
 504 /* this one is very careful, as it is the first function
 505  * to parse the userspace data
 506  */
 507 static inline int
 508 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 509                                const struct ebt_table_info *newinfo,
 510                                unsigned int *n, unsigned int *cnt,
 511                                unsigned int *totalcnt, unsigned int *udc_cnt)
 512 {
 513         int i;
 514
 515         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 516                 if ((void *)e == (void *)newinfo->hook_entry[i])
 517                         break;
 518         }
 519         /* beginning of a new chain
 520          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 521          */
 522         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 523                 /* this checks if the previous chain has as many entries
 524                  * as it said it has
 525                  */
 526                 if (*n != *cnt) {
 527                         BUGPRINT("nentries does not equal the nr of entries "
 528                                  "in the chain\n");
 529                         return -EINVAL;
 530                 }
 531                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 532                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 533                         /* only RETURN from udc */
 534                         if (i != NF_BR_NUMHOOKS ||
 535                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 536                                 BUGPRINT("bad policy\n");
 537                                 return -EINVAL;
 538                         }
 539                 }
 540                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 541                         (*udc_cnt)++;
 542                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 543                         BUGPRINT("counter_offset != totalcnt");
 544                         return -EINVAL;
 545                 }
 546                 *n = ((struct ebt_entries *)e)->nentries;
 547                 *cnt = 0;
 548                 return 0;
 549         }
 550         /* a plain old entry, heh */
 551         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 552            e->watchers_offset > e->target_offset ||
 553            e->target_offset >= e->next_offset) {
 554                 BUGPRINT("entry offsets not in right order\n");
 555                 return -EINVAL;
 556         }
 557         /* this is not checked anywhere else */
 558         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 559                 BUGPRINT("target size too small\n");
 560                 return -EINVAL;
 561         }
 562         (*cnt)++;
 563         (*totalcnt)++;
 564         return 0;
 565 }
 566
 567 struct ebt_cl_stack {
 568         struct ebt_chainstack cs;
 569         int from;
 570         unsigned int hookmask;
 571 };
 572
 573 /* We need these positions to check that the jumps to a different part of the
 574  * entries is a jump to the beginning of a new chain.
 575  */
 576 static inline int
 577 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 578                       unsigned int *n, struct ebt_cl_stack *udc)
 579 {
 580         int i;
 581
 582         /* we're only interested in chain starts */
 583         if (e->bitmask)
 584                 return 0;
 585         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 586                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 587                         break;
 588         }
 589         /* only care about udc */
 590         if (i != NF_BR_NUMHOOKS)
 591                 return 0;
 592
 593         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 594         /* these initialisations are depended on later in check_chainloops() */
 595         udc[*n].cs.n = 0;
 596         udc[*n].hookmask = 0;
 597
 598         (*n)++;
 599         return 0;
 600 }
 601
 602 static inline int
 603 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 604 {
 605         struct xt_mtdtor_param par;
 606
 607         if (i && (*i)-- == 0)
 608                 return 1;
 609
 610         par.net       = net;
 611         par.match     = m->u.match;
 612         par.matchinfo = m->data;
 613         par.family    = NFPROTO_BRIDGE;
 614         if (par.match->destroy != NULL)
 615                 par.match->destroy(&par);
 616         module_put(par.match->me);
 617         return 0;
 618 }
 619
 620 static inline int
 621 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 622 {
 623         struct xt_tgdtor_param par;
 624
 625         if (i && (*i)-- == 0)
 626                 return 1;
 627
 628         par.net      = net;
 629         par.target   = w->u.watcher;
 630         par.targinfo = w->data;
 631         par.family   = NFPROTO_BRIDGE;
 632         if (par.target->destroy != NULL)
 633                 par.target->destroy(&par);
 634         module_put(par.target->me);
 635         return 0;
 636 }
 637
 638 static inline int
 639 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 640 {
 641         struct xt_tgdtor_param par;
 642         struct ebt_entry_target *t;
 643
 644         if (e->bitmask == 0)
 645                 return 0;
 646         /* we're done */
 647         if (cnt && (*cnt)-- == 0)
 648                 return 1;
 649         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 650         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 651         t = ebt_get_target(e);
 652
 653         par.net      = net;
 654         par.target   = t->u.target;
 655         par.targinfo = t->data;
 656         par.family   = NFPROTO_BRIDGE;
 657         if (par.target->destroy != NULL)
 658                 par.target->destroy(&par);
 659         module_put(par.target->me);
 660         return 0;
 661 }
 662
 663 static inline int
 664 ebt_check_entry(struct ebt_entry *e, struct net *net,
 665                 const struct ebt_table_info *newinfo,
 666                 const char *name, unsigned int *cnt,
 667                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 668 {
 669         struct ebt_entry_target *t;
 670         struct xt_target *target;
 671         unsigned int i, j, hook = 0, hookmask = 0;
 672         size_t gap;
 673         int ret;
 674         struct xt_mtchk_param mtpar;
 675         struct xt_tgchk_param tgpar;
 676
 677         /* don't mess with the struct ebt_entries */
 678         if (e->bitmask == 0)
 679                 return 0;
 680
 681         if (e->bitmask & ~EBT_F_MASK) {
 682                 BUGPRINT("Unknown flag for bitmask\n");
 683                 return -EINVAL;
 684         }
 685         if (e->invflags & ~EBT_INV_MASK) {
 686                 BUGPRINT("Unknown flag for inv bitmask\n");
 687                 return -EINVAL;
 688         }
 689         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 690                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 691                 return -EINVAL;
 692         }
 693         /* what hook do we belong to? */
 694         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 695                 if (!newinfo->hook_entry[i])
 696                         continue;
 697                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 698                         hook = i;
 699                 else
 700                         break;
 701         }
 702         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 703          * a base chain
 704          */
 705         if (i < NF_BR_NUMHOOKS)
 706                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 707         else {
 708                 for (i = 0; i < udc_cnt; i++)
 709                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 710                                 break;
 711                 if (i == 0)
 712                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 713                 else
 714                         hookmask = cl_s[i - 1].hookmask;
 715         }
 716         i = 0;
 717
 718         memset(&mtpar, 0, sizeof(mtpar));
 719         memset(&tgpar, 0, sizeof(tgpar));
 720         mtpar.net       = tgpar.net       = net;
 721         mtpar.table     = tgpar.table     = name;
 722         mtpar.entryinfo = tgpar.entryinfo = e;
 723         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 724         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 725         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 726         if (ret != 0)
 727                 goto cleanup_matches;
 728         j = 0;
 729         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 730         if (ret != 0)
 731                 goto cleanup_watchers;
 732         t = ebt_get_target(e);
 733         gap = e->next_offset - e->target_offset;
 734
 735         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 736         if (IS_ERR(target)) {
 737                 ret = PTR_ERR(target);
 738                 goto cleanup_watchers;
 739         }
 740
 741         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 742         if (target->family != NFPROTO_BRIDGE) {
 743                 module_put(target->me);
 744                 ret = -ENOENT;
 745                 goto cleanup_watchers;
 746         }
 747
 748         t->u.target = target;
 749         if (t->u.target == &ebt_standard_target) {
 750                 if (gap < sizeof(struct ebt_standard_target)) {
 751                         BUGPRINT("Standard target size too big\n");
 752                         ret = -EFAULT;
 753                         goto cleanup_watchers;
 754                 }
 755                 if (((struct ebt_standard_target *)t)->verdict <
 756                    -NUM_STANDARD_TARGETS) {
 757                         BUGPRINT("Invalid standard target\n");
 758                         ret = -EFAULT;
 759                         goto cleanup_watchers;
 760                 }
 761         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 762                 module_put(t->u.target->me);
 763                 ret = -EFAULT;
 764                 goto cleanup_watchers;
 765         }
 766
 767         tgpar.target   = target;
 768         tgpar.targinfo = t->data;
 769         ret = xt_check_target(&tgpar, t->target_size,
 770               e->ethproto, e->invflags & EBT_IPROTO);
 771         if (ret < 0) {
 772                 module_put(target->me);
 773                 goto cleanup_watchers;
 774         }
 775         (*cnt)++;
 776         return 0;
 777 cleanup_watchers:
 778         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 779 cleanup_matches:
 780         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 781         return ret;
 782 }
 783
 784 /* checks for loops and sets the hook mask for udc
 785  * the hook mask for udc tells us from which base chains the udc can be
 786  * accessed. This mask is a parameter to the check() functions of the extensions
 787  */
 788 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 789                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 790 {
 791         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 792         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 793         const struct ebt_entry_target *t;
 794
 795         while (pos < nentries || chain_nr != -1) {
 796                 /* end of udc, go back one 'recursion' step */
 797                 if (pos == nentries) {
 798                         /* put back values of the time when this chain was called */
 799                         e = cl_s[chain_nr].cs.e;
 800                         if (cl_s[chain_nr].from != -1)
 801                                 nentries =
 802                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 803                         else
 804                                 nentries = chain->nentries;
 805                         pos = cl_s[chain_nr].cs.n;
 806                         /* make sure we won't see a loop that isn't one */
 807                         cl_s[chain_nr].cs.n = 0;
 808                         chain_nr = cl_s[chain_nr].from;
 809                         if (pos == nentries)
 810                                 continue;
 811                 }
 812                 t = ebt_get_target_c(e);
 813                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 814                         goto letscontinue;
 815                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 816                    e->next_offset) {
 817                         BUGPRINT("Standard target size too big\n");
 818                         return -1;
 819                 }
 820                 verdict = ((struct ebt_standard_target *)t)->verdict;
 821                 if (verdict >= 0) { /* jump to another chain */
 822                         struct ebt_entries *hlp2 =
 823                            (struct ebt_entries *)(base + verdict);
 824                         for (i = 0; i < udc_cnt; i++)
 825                                 if (hlp2 == cl_s[i].cs.chaininfo)
 826                                         break;
 827                         /* bad destination or loop */
 828                         if (i == udc_cnt) {
 829                                 BUGPRINT("bad destination\n");
 830                                 return -1;
 831                         }
 832                         if (cl_s[i].cs.n) {
 833                                 BUGPRINT("loop\n");
 834                                 return -1;
 835                         }
 836                         if (cl_s[i].hookmask & (1 << hooknr))
 837                                 goto letscontinue;
 838                         /* this can't be 0, so the loop test is correct */
 839                         cl_s[i].cs.n = pos + 1;
 840                         pos = 0;
 841                         cl_s[i].cs.e = ebt_next_entry(e);
 842                         e = (struct ebt_entry *)(hlp2->data);
 843                         nentries = hlp2->nentries;
 844                         cl_s[i].from = chain_nr;
 845                         chain_nr = i;
 846                         /* this udc is accessible from the base chain for hooknr */
 847                         cl_s[i].hookmask |= (1 << hooknr);
 848                         continue;
 849                 }
 850 letscontinue:
 851                 e = ebt_next_entry(e);
 852                 pos++;
 853         }
 854         return 0;
 855 }
 856
 857 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 858 static int translate_table(struct net *net, const char *name,
 859                            struct ebt_table_info *newinfo)
 860 {
 861         unsigned int i, j, k, udc_cnt;
 862         int ret;
 863         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 864
 865         i = 0;
 866         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 867                 i++;
 868         if (i == NF_BR_NUMHOOKS) {
 869                 BUGPRINT("No valid hooks specified\n");
 870                 return -EINVAL;
 871         }
 872         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 873                 BUGPRINT("Chains don't start at beginning\n");
 874                 return -EINVAL;
 875         }
 876         /* make sure chains are ordered after each other in same order
 877          * as their corresponding hooks
 878          */
 879         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 880                 if (!newinfo->hook_entry[j])
 881                         continue;
 882                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 883                         BUGPRINT("Hook order must be followed\n");
 884                         return -EINVAL;
 885                 }
 886                 i = j;
 887         }
 888
 889         /* do some early checkings and initialize some things */
 890         i = 0; /* holds the expected nr. of entries for the chain */
 891         j = 0; /* holds the up to now counted entries for the chain */
 892         k = 0; /* holds the total nr. of entries, should equal
 893                 * newinfo->nentries afterwards
 894                 */
 895         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 896         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 897            ebt_check_entry_size_and_hooks, newinfo,
 898            &i, &j, &k, &udc_cnt);
 899
 900         if (ret != 0)
 901                 return ret;
 902
 903         if (i != j) {
 904                 BUGPRINT("nentries does not equal the nr of entries in the "
 905                          "(last) chain\n");
 906                 return -EINVAL;
 907         }
 908         if (k != newinfo->nentries) {
 909                 BUGPRINT("Total nentries is wrong\n");
 910                 return -EINVAL;
 911         }
 912
 913         /* get the location of the udc, put them in an array
 914          * while we're at it, allocate the chainstack
 915          */
 916         if (udc_cnt) {
 917                 /* this will get free'd in do_replace()/ebt_register_table()
 918                  * if an error occurs
 919                  */
 920                 newinfo->chainstack =
 921                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 922                 if (!newinfo->chainstack)
 923                         return -ENOMEM;
 924                 for_each_possible_cpu(i) {
 925                         newinfo->chainstack[i] =
 926                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
 927                         if (!newinfo->chainstack[i]) {
 928                                 while (i)
 929                                         vfree(newinfo->chainstack[--i]);
 930                                 vfree(newinfo->chainstack);
 931                                 newinfo->chainstack = NULL;
 932                                 return -ENOMEM;
 933                         }
 934                 }
 935
 936                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
 937                 if (!cl_s)
 938                         return -ENOMEM;
 939                 i = 0; /* the i'th udc */
 940                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 941                    ebt_get_udc_positions, newinfo, &i, cl_s);
 942                 /* sanity check */
 943                 if (i != udc_cnt) {
 944                         BUGPRINT("i != udc_cnt\n");
 945                         vfree(cl_s);
 946                         return -EFAULT;
 947                 }
 948         }
 949
 950         /* Check for loops */
 951         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 952                 if (newinfo->hook_entry[i])
 953                         if (check_chainloops(newinfo->hook_entry[i],
 954                            cl_s, udc_cnt, i, newinfo->entries)) {
 955                                 vfree(cl_s);
 956                                 return -EINVAL;
 957                         }
 958
 959         /* we now know the following (along with E=mc²):
 960          *  - the nr of entries in each chain is right
 961          *  - the size of the allocated space is right
 962          *  - all valid hooks have a corresponding chain
 963          *  - there are no loops
 964          *  - wrong data can still be on the level of a single entry
 965          *  - could be there are jumps to places that are not the
 966          *    beginning of a chain. This can only occur in chains that
 967          *    are not accessible from any base chains, so we don't care.
 968          */
 969
 970         /* used to know what we need to clean up if something goes wrong */
 971         i = 0;
 972         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 973            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 974         if (ret != 0) {
 975                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 976                                   ebt_cleanup_entry, net, &i);
 977         }
 978         vfree(cl_s);
 979         return ret;
 980 }
 981
 982 /* called under write_lock */
 983 static void get_counters(const struct ebt_counter *oldcounters,
 984                          struct ebt_counter *counters, unsigned int nentries)
 985 {
 986         int i, cpu;
 987         struct ebt_counter *counter_base;
 988
 989         /* counters of cpu 0 */
 990         memcpy(counters, oldcounters,
 991                sizeof(struct ebt_counter) * nentries);
 992
 993         /* add other counters to those of cpu 0 */
 994         for_each_possible_cpu(cpu) {
 995                 if (cpu == 0)
 996                         continue;
 997                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 998                 for (i = 0; i < nentries; i++)
 999                         ADD_COUNTER(counters[i], counter_base[i].pcnt,
1000                                     counter_base[i].bcnt);
1001         }
1002 }
1003
1004 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1005                               struct ebt_table_info *newinfo)
1006 {
1007         int ret;
1008         struct ebt_counter *counterstmp = NULL;
1009         /* used to be able to unlock earlier */
1010         struct ebt_table_info *table;
1011         struct ebt_table *t;
1012
1013         /* the user wants counters back
1014          * the check on the size is done later, when we have the lock
1015          */
1016         if (repl->num_counters) {
1017                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1018                 counterstmp = vmalloc(size);
1019                 if (!counterstmp)
1020                         return -ENOMEM;
1021         }
1022
1023         newinfo->chainstack = NULL;
1024         ret = ebt_verify_pointers(repl, newinfo);
1025         if (ret != 0)
1026                 goto free_counterstmp;
1027
1028         ret = translate_table(net, repl->name, newinfo);
1029
1030         if (ret != 0)
1031                 goto free_counterstmp;
1032
1033         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1034         if (!t) {
1035                 ret = -ENOENT;
1036                 goto free_iterate;
1037         }
1038
1039         /* the table doesn't like it */
1040         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1041                 goto free_unlock;
1042
1043         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1044                 BUGPRINT("Wrong nr. of counters requested\n");
1045                 ret = -EINVAL;
1046                 goto free_unlock;
1047         }
1048
1049         /* we have the mutex lock, so no danger in reading this pointer */
1050         table = t->private;
1051         /* make sure the table can only be rmmod'ed if it contains no rules */
1052         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1053                 ret = -ENOENT;
1054                 goto free_unlock;
1055         } else if (table->nentries && !newinfo->nentries)
1056                 module_put(t->me);
1057         /* we need an atomic snapshot of the counters */
1058         write_lock_bh(&t->lock);
1059         if (repl->num_counters)
1060                 get_counters(t->private->counters, counterstmp,
1061                    t->private->nentries);
1062
1063         t->private = newinfo;
1064         write_unlock_bh(&t->lock);
1065         mutex_unlock(&ebt_mutex);
1066         /* so, a user can change the chains while having messed up her counter
1067          * allocation. Only reason why this is done is because this way the lock
1068          * is held only once, while this doesn't bring the kernel into a
1069          * dangerous state.
1070          */
1071         if (repl->num_counters &&
1072            copy_to_user(repl->counters, counterstmp,
1073            repl->num_counters * sizeof(struct ebt_counter))) {
1074                 /* Silent error, can't fail, new table is already in place */
1075                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1076         }
1077
1078         /* decrease module count and free resources */
1079         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1080                           ebt_cleanup_entry, net, NULL);
1081
1082         vfree(table->entries);
1083         ebt_free_table_info(table);
1084         vfree(table);
1085         vfree(counterstmp);
1086
1087 #ifdef CONFIG_AUDIT
1088         if (audit_enabled) {
1089                 audit_log(audit_context(), GFP_KERNEL,
1090                           AUDIT_NETFILTER_CFG,
1091                           "table=%s family=%u entries=%u",
1092                           repl->name, AF_BRIDGE, repl->nentries);
1093         }
1094 #endif
1095         return ret;
1096
1097 free_unlock:
1098         mutex_unlock(&ebt_mutex);
1099 free_iterate:
1100         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1101                           ebt_cleanup_entry, net, NULL);
1102 free_counterstmp:
1103         vfree(counterstmp);
1104         /* can be initialized in translate_table() */
1105         ebt_free_table_info(newinfo);
1106         return ret;
1107 }
1108
1109 /* replace the table */
1110 static int do_replace(struct net *net, const void __user *user,
1111                       unsigned int len)
1112 {
1113         int ret, countersize;
1114         struct ebt_table_info *newinfo;
1115         struct ebt_replace tmp;
1116
1117         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1118                 return -EFAULT;
1119
1120         if (len != sizeof(tmp) + tmp.entries_size) {
1121                 BUGPRINT("Wrong len argument\n");
1122                 return -EINVAL;
1123         }
1124
1125         if (tmp.entries_size == 0) {
1126                 BUGPRINT("Entries_size never zero\n");
1127                 return -EINVAL;
1128         }
1129         /* overflow check */
1130         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1131                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1132                 return -ENOMEM;
1133         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1134                 return -ENOMEM;
1135
1136         tmp.name[sizeof(tmp.name) - 1] = 0;
1137
1138         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1139         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1140         if (!newinfo)
1141                 return -ENOMEM;
1142
1143         if (countersize)
1144                 memset(newinfo->counters, 0, countersize);
1145
1146         newinfo->entries = vmalloc(tmp.entries_size);
1147         if (!newinfo->entries) {
1148                 ret = -ENOMEM;
1149                 goto free_newinfo;
1150         }
1151         if (copy_from_user(
1152            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1153                 BUGPRINT("Couldn't copy entries from userspace\n");
1154                 ret = -EFAULT;
1155                 goto free_entries;
1156         }
1157
1158         ret = do_replace_finish(net, &tmp, newinfo);
1159         if (ret == 0)
1160                 return ret;
1161 free_entries:
1162         vfree(newinfo->entries);
1163 free_newinfo:
1164         vfree(newinfo);
1165         return ret;
1166 }
1167
1168 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1169 {
1170         mutex_lock(&ebt_mutex);
1171         list_del(&table->list);
1172         mutex_unlock(&ebt_mutex);
1173         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1174                           ebt_cleanup_entry, net, NULL);
1175         if (table->private->nentries)
1176                 module_put(table->me);
1177         vfree(table->private->entries);
1178         ebt_free_table_info(table->private);
1179         vfree(table->private);
1180         kfree(table);
1181 }
1182
1183 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1184                        const struct nf_hook_ops *ops, struct ebt_table **res)
1185 {
1186         struct ebt_table_info *newinfo;
1187         struct ebt_table *t, *table;
1188         struct ebt_replace_kernel *repl;
1189         int ret, i, countersize;
1190         void *p;
1191
1192         if (input_table == NULL || (repl = input_table->table) == NULL ||
1193             repl->entries == NULL || repl->entries_size == 0 ||
1194             repl->counters != NULL || input_table->private != NULL) {
1195                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1196                 return -EINVAL;
1197         }
1198
1199         /* Don't add one table to multiple lists. */
1200         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1201         if (!table) {
1202                 ret = -ENOMEM;
1203                 goto out;
1204         }
1205
1206         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1207         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1208         ret = -ENOMEM;
1209         if (!newinfo)
1210                 goto free_table;
1211
1212         p = vmalloc(repl->entries_size);
1213         if (!p)
1214                 goto free_newinfo;
1215
1216         memcpy(p, repl->entries, repl->entries_size);
1217         newinfo->entries = p;
1218
1219         newinfo->entries_size = repl->entries_size;
1220         newinfo->nentries = repl->nentries;
1221
1222         if (countersize)
1223                 memset(newinfo->counters, 0, countersize);
1224
1225         /* fill in newinfo and parse the entries */
1226         newinfo->chainstack = NULL;
1227         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1228                 if ((repl->valid_hooks & (1 << i)) == 0)
1229                         newinfo->hook_entry[i] = NULL;
1230                 else
1231                         newinfo->hook_entry[i] = p +
1232                                 ((char *)repl->hook_entry[i] - repl->entries);
1233         }
1234         ret = translate_table(net, repl->name, newinfo);
1235         if (ret != 0) {
1236                 BUGPRINT("Translate_table failed\n");
1237                 goto free_chainstack;
1238         }
1239
1240         if (table->check && table->check(newinfo, table->valid_hooks)) {
1241                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1242                 ret = -EINVAL;
1243                 goto free_chainstack;
1244         }
1245
1246         table->private = newinfo;
1247         rwlock_init(&table->lock);
1248         mutex_lock(&ebt_mutex);
1249         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1250                 if (strcmp(t->name, table->name) == 0) {
1251                         ret = -EEXIST;
1252                         BUGPRINT("Table name already exists\n");
1253                         goto free_unlock;
1254                 }
1255         }
1256
1257         /* Hold a reference count if the chains aren't empty */
1258         if (newinfo->nentries && !try_module_get(table->me)) {
1259                 ret = -ENOENT;
1260                 goto free_unlock;
1261         }
1262         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1263         mutex_unlock(&ebt_mutex);
1264
1265         WRITE_ONCE(*res, table);
1266
1267         if (!ops)
1268                 return 0;
1269
1270         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1271         if (ret) {
1272                 __ebt_unregister_table(net, table);
1273                 *res = NULL;
1274         }
1275
1276         return ret;
1277 free_unlock:
1278         mutex_unlock(&ebt_mutex);
1279 free_chainstack:
1280         ebt_free_table_info(newinfo);
1281         vfree(newinfo->entries);
1282 free_newinfo:
1283         vfree(newinfo);
1284 free_table:
1285         kfree(table);
1286 out:
1287         return ret;
1288 }
1289
1290 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1291                           const struct nf_hook_ops *ops)
1292 {
1293         if (ops)
1294                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1295         __ebt_unregister_table(net, table);
1296 }
1297
1298 /* userspace just supplied us with counters */
1299 static int do_update_counters(struct net *net, const char *name,
1300                                 struct ebt_counter __user *counters,
1301                                 unsigned int num_counters,
1302                                 const void __user *user, unsigned int len)
1303 {
1304         int i, ret;
1305         struct ebt_counter *tmp;
1306         struct ebt_table *t;
1307
1308         if (num_counters == 0)
1309                 return -EINVAL;
1310
1311         tmp = vmalloc(num_counters * sizeof(*tmp));
1312         if (!tmp)
1313                 return -ENOMEM;
1314
1315         t = find_table_lock(net, name, &ret, &ebt_mutex);
1316         if (!t)
1317                 goto free_tmp;
1318
1319         if (num_counters != t->private->nentries) {
1320                 BUGPRINT("Wrong nr of counters\n");
1321                 ret = -EINVAL;
1322                 goto unlock_mutex;
1323         }
1324
1325         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1326                 ret = -EFAULT;
1327                 goto unlock_mutex;
1328         }
1329
1330         /* we want an atomic add of the counters */
1331         write_lock_bh(&t->lock);
1332
1333         /* we add to the counters of the first cpu */
1334         for (i = 0; i < num_counters; i++)
1335                 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt);
1336
1337         write_unlock_bh(&t->lock);
1338         ret = 0;
1339 unlock_mutex:
1340         mutex_unlock(&ebt_mutex);
1341 free_tmp:
1342         vfree(tmp);
1343         return ret;
1344 }
1345
1346 static int update_counters(struct net *net, const void __user *user,
1347                             unsigned int len)
1348 {
1349         struct ebt_replace hlp;
1350
1351         if (copy_from_user(&hlp, user, sizeof(hlp)))
1352                 return -EFAULT;
1353
1354         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1355                 return -EINVAL;
1356
1357         return do_update_counters(net, hlp.name, hlp.counters,
1358                                 hlp.num_counters, user, len);
1359 }
1360
1361 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1362                                   const char *data, int entrysize,
1363                                   int usersize, int datasize, u8 revision)
1364 {
1365         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1366
1367         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1368          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1369          */
1370         strlcpy(name, _name, sizeof(name));
1371         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1372             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1373             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1374             xt_data_to_user(um + entrysize, data, usersize, datasize,
1375                             XT_ALIGN(datasize)))
1376                 return -EFAULT;
1377
1378         return 0;
1379 }
1380
1381 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1382                                     const char *base, char __user *ubase)
1383 {
1384         return ebt_obj_to_user(ubase + ((char *)m - base),
1385                                m->u.match->name, m->data, sizeof(*m),
1386                                m->u.match->usersize, m->match_size,
1387                                m->u.match->revision);
1388 }
1389
1390 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1391                                       const char *base, char __user *ubase)
1392 {
1393         return ebt_obj_to_user(ubase + ((char *)w - base),
1394                                w->u.watcher->name, w->data, sizeof(*w),
1395                                w->u.watcher->usersize, w->watcher_size,
1396                                w->u.watcher->revision);
1397 }
1398
1399 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1400                                     char __user *ubase)
1401 {
1402         int ret;
1403         char __user *hlp;
1404         const struct ebt_entry_target *t;
1405
1406         if (e->bitmask == 0) {
1407                 /* special case !EBT_ENTRY_OR_ENTRIES */
1408                 if (copy_to_user(ubase + ((char *)e - base), e,
1409                                  sizeof(struct ebt_entries)))
1410                         return -EFAULT;
1411                 return 0;
1412         }
1413
1414         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1415                 return -EFAULT;
1416
1417         hlp = ubase + (((char *)e + e->target_offset) - base);
1418         t = ebt_get_target_c(e);
1419
1420         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1421         if (ret != 0)
1422                 return ret;
1423         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1424         if (ret != 0)
1425                 return ret;
1426         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1427                               t->u.target->usersize, t->target_size,
1428                               t->u.target->revision);
1429         if (ret != 0)
1430                 return ret;
1431
1432         return 0;
1433 }
1434
1435 static int copy_counters_to_user(struct ebt_table *t,
1436                                  const struct ebt_counter *oldcounters,
1437                                  void __user *user, unsigned int num_counters,
1438                                  unsigned int nentries)
1439 {
1440         struct ebt_counter *counterstmp;
1441         int ret = 0;
1442
1443         /* userspace might not need the counters */
1444         if (num_counters == 0)
1445                 return 0;
1446
1447         if (num_counters != nentries) {
1448                 BUGPRINT("Num_counters wrong\n");
1449                 return -EINVAL;
1450         }
1451
1452         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1453         if (!counterstmp)
1454                 return -ENOMEM;
1455
1456         write_lock_bh(&t->lock);
1457         get_counters(oldcounters, counterstmp, nentries);
1458         write_unlock_bh(&t->lock);
1459
1460         if (copy_to_user(user, counterstmp,
1461            nentries * sizeof(struct ebt_counter)))
1462                 ret = -EFAULT;
1463         vfree(counterstmp);
1464         return ret;
1465 }
1466
1467 /* called with ebt_mutex locked */
1468 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1469                                    const int *len, int cmd)
1470 {
1471         struct ebt_replace tmp;
1472         const struct ebt_counter *oldcounters;
1473         unsigned int entries_size, nentries;
1474         int ret;
1475         char *entries;
1476
1477         if (cmd == EBT_SO_GET_ENTRIES) {
1478                 entries_size = t->private->entries_size;
1479                 nentries = t->private->nentries;
1480                 entries = t->private->entries;
1481                 oldcounters = t->private->counters;
1482         } else {
1483                 entries_size = t->table->entries_size;
1484                 nentries = t->table->nentries;
1485                 entries = t->table->entries;
1486                 oldcounters = t->table->counters;
1487         }
1488
1489         if (copy_from_user(&tmp, user, sizeof(tmp)))
1490                 return -EFAULT;
1491
1492         if (*len != sizeof(struct ebt_replace) + entries_size +
1493            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1494                 return -EINVAL;
1495
1496         if (tmp.nentries != nentries) {
1497                 BUGPRINT("Nentries wrong\n");
1498                 return -EINVAL;
1499         }
1500
1501         if (tmp.entries_size != entries_size) {
1502                 BUGPRINT("Wrong size\n");
1503                 return -EINVAL;
1504         }
1505
1506         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1507                                         tmp.num_counters, nentries);
1508         if (ret)
1509                 return ret;
1510
1511         /* set the match/watcher/target names right */
1512         return EBT_ENTRY_ITERATE(entries, entries_size,
1513            ebt_entry_to_user, entries, tmp.entries);
1514 }
1515
1516 static int do_ebt_set_ctl(struct sock *sk,
1517         int cmd, void __user *user, unsigned int len)
1518 {
1519         int ret;
1520         struct net *net = sock_net(sk);
1521
1522         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1523                 return -EPERM;
1524
1525         switch (cmd) {
1526         case EBT_SO_SET_ENTRIES:
1527                 ret = do_replace(net, user, len);
1528                 break;
1529         case EBT_SO_SET_COUNTERS:
1530                 ret = update_counters(net, user, len);
1531                 break;
1532         default:
1533                 ret = -EINVAL;
1534         }
1535         return ret;
1536 }
1537
1538 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1539 {
1540         int ret;
1541         struct ebt_replace tmp;
1542         struct ebt_table *t;
1543         struct net *net = sock_net(sk);
1544
1545         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1546                 return -EPERM;
1547
1548         if (copy_from_user(&tmp, user, sizeof(tmp)))
1549                 return -EFAULT;
1550
1551         tmp.name[sizeof(tmp.name) - 1] = '\0';
1552
1553         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1554         if (!t)
1555                 return ret;
1556
1557         switch (cmd) {
1558         case EBT_SO_GET_INFO:
1559         case EBT_SO_GET_INIT_INFO:
1560                 if (*len != sizeof(struct ebt_replace)) {
1561                         ret = -EINVAL;
1562                         mutex_unlock(&ebt_mutex);
1563                         break;
1564                 }
1565                 if (cmd == EBT_SO_GET_INFO) {
1566                         tmp.nentries = t->private->nentries;
1567                         tmp.entries_size = t->private->entries_size;
1568                         tmp.valid_hooks = t->valid_hooks;
1569                 } else {
1570                         tmp.nentries = t->table->nentries;
1571                         tmp.entries_size = t->table->entries_size;
1572                         tmp.valid_hooks = t->table->valid_hooks;
1573                 }
1574                 mutex_unlock(&ebt_mutex);
1575                 if (copy_to_user(user, &tmp, *len) != 0) {
1576                         BUGPRINT("c2u Didn't work\n");
1577                         ret = -EFAULT;
1578                         break;
1579                 }
1580                 ret = 0;
1581                 break;
1582
1583         case EBT_SO_GET_ENTRIES:
1584         case EBT_SO_GET_INIT_ENTRIES:
1585                 ret = copy_everything_to_user(t, user, len, cmd);
1586                 mutex_unlock(&ebt_mutex);
1587                 break;
1588
1589         default:
1590                 mutex_unlock(&ebt_mutex);
1591                 ret = -EINVAL;
1592         }
1593
1594         return ret;
1595 }
1596
1597 #ifdef CONFIG_COMPAT
1598 /* 32 bit-userspace compatibility definitions. */
1599 struct compat_ebt_replace {
1600         char name[EBT_TABLE_MAXNAMELEN];
1601         compat_uint_t valid_hooks;
1602         compat_uint_t nentries;
1603         compat_uint_t entries_size;
1604         /* start of the chains */
1605         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1606         /* nr of counters userspace expects back */
1607         compat_uint_t num_counters;
1608         /* where the kernel will put the old counters. */
1609         compat_uptr_t counters;
1610         compat_uptr_t entries;
1611 };
1612
1613 /* struct ebt_entry_match, _target and _watcher have same layout */
1614 struct compat_ebt_entry_mwt {
1615         union {
1616                 struct {
1617                         char name[EBT_EXTENSION_MAXNAMELEN];
1618                         u8 revision;
1619                 };
1620                 compat_uptr_t ptr;
1621         } u;
1622         compat_uint_t match_size;
1623         compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace))));
1624 };
1625
1626 /* account for possible padding between match_size and ->data */
1627 static int ebt_compat_entry_padsize(void)
1628 {
1629         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1630                         sizeof(struct compat_ebt_entry_mwt));
1631         return (int) sizeof(struct ebt_entry_match) -
1632                         sizeof(struct compat_ebt_entry_mwt);
1633 }
1634
1635 static int ebt_compat_match_offset(const struct xt_match *match,
1636                                    unsigned int userlen)
1637 {
1638         /* ebt_among needs special handling. The kernel .matchsize is
1639          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1640          * value is expected.
1641          * Example: userspace sends 4500, ebt_among.c wants 4504.
1642          */
1643         if (unlikely(match->matchsize == -1))
1644                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1645         return xt_compat_match_offset(match);
1646 }
1647
1648 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1649                                 unsigned int *size)
1650 {
1651         const struct xt_match *match = m->u.match;
1652         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1653         int off = ebt_compat_match_offset(match, m->match_size);
1654         compat_uint_t msize = m->match_size - off;
1655
1656         if (WARN_ON(off >= m->match_size))
1657                 return -EINVAL;
1658
1659         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1660             put_user(match->revision, &cm->u.revision) ||
1661             put_user(msize, &cm->match_size))
1662                 return -EFAULT;
1663
1664         if (match->compat_to_user) {
1665                 if (match->compat_to_user(cm->data, m->data))
1666                         return -EFAULT;
1667         } else {
1668                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1669                                     COMPAT_XT_ALIGN(msize)))
1670                         return -EFAULT;
1671         }
1672
1673         *size -= ebt_compat_entry_padsize() + off;
1674         *dstptr = cm->data;
1675         *dstptr += msize;
1676         return 0;
1677 }
1678
1679 static int compat_target_to_user(struct ebt_entry_target *t,
1680                                  void __user **dstptr,
1681                                  unsigned int *size)
1682 {
1683         const struct xt_target *target = t->u.target;
1684         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1685         int off = xt_compat_target_offset(target);
1686         compat_uint_t tsize = t->target_size - off;
1687
1688         if (WARN_ON(off >= t->target_size))
1689                 return -EINVAL;
1690
1691         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1692             put_user(target->revision, &cm->u.revision) ||
1693             put_user(tsize, &cm->match_size))
1694                 return -EFAULT;
1695
1696         if (target->compat_to_user) {
1697                 if (target->compat_to_user(cm->data, t->data))
1698                         return -EFAULT;
1699         } else {
1700                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1701                                     COMPAT_XT_ALIGN(tsize)))
1702                         return -EFAULT;
1703         }
1704
1705         *size -= ebt_compat_entry_padsize() + off;
1706         *dstptr = cm->data;
1707         *dstptr += tsize;
1708         return 0;
1709 }
1710
1711 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1712                                   void __user **dstptr,
1713                                   unsigned int *size)
1714 {
1715         return compat_target_to_user((struct ebt_entry_target *)w,
1716                                                         dstptr, size);
1717 }
1718
1719 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1720                                 unsigned int *size)
1721 {
1722         struct ebt_entry_target *t;
1723         struct ebt_entry __user *ce;
1724         u32 watchers_offset, target_offset, next_offset;
1725         compat_uint_t origsize;
1726         int ret;
1727
1728         if (e->bitmask == 0) {
1729                 if (*size < sizeof(struct ebt_entries))
1730                         return -EINVAL;
1731                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1732                         return -EFAULT;
1733
1734                 *dstptr += sizeof(struct ebt_entries);
1735                 *size -= sizeof(struct ebt_entries);
1736                 return 0;
1737         }
1738
1739         if (*size < sizeof(*ce))
1740                 return -EINVAL;
1741
1742         ce = *dstptr;
1743         if (copy_to_user(ce, e, sizeof(*ce)))
1744                 return -EFAULT;
1745
1746         origsize = *size;
1747         *dstptr += sizeof(*ce);
1748
1749         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1750         if (ret)
1751                 return ret;
1752         watchers_offset = e->watchers_offset - (origsize - *size);
1753
1754         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1755         if (ret)
1756                 return ret;
1757         target_offset = e->target_offset - (origsize - *size);
1758
1759         t = ebt_get_target(e);
1760
1761         ret = compat_target_to_user(t, dstptr, size);
1762         if (ret)
1763                 return ret;
1764         next_offset = e->next_offset - (origsize - *size);
1765
1766         if (put_user(watchers_offset, &ce->watchers_offset) ||
1767             put_user(target_offset, &ce->target_offset) ||
1768             put_user(next_offset, &ce->next_offset))
1769                 return -EFAULT;
1770
1771         *size -= sizeof(*ce);
1772         return 0;
1773 }
1774
1775 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1776 {
1777         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1778         *off += ebt_compat_entry_padsize();
1779         return 0;
1780 }
1781
1782 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1783 {
1784         *off += xt_compat_target_offset(w->u.watcher);
1785         *off += ebt_compat_entry_padsize();
1786         return 0;
1787 }
1788
1789 static int compat_calc_entry(const struct ebt_entry *e,
1790                              const struct ebt_table_info *info,
1791                              const void *base,
1792                              struct compat_ebt_replace *newinfo)
1793 {
1794         const struct ebt_entry_target *t;
1795         unsigned int entry_offset;
1796         int off, ret, i;
1797
1798         if (e->bitmask == 0)
1799                 return 0;
1800
1801         off = 0;
1802         entry_offset = (void *)e - base;
1803
1804         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1805         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1806
1807         t = ebt_get_target_c(e);
1808
1809         off += xt_compat_target_offset(t->u.target);
1810         off += ebt_compat_entry_padsize();
1811
1812         newinfo->entries_size -= off;
1813
1814         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1815         if (ret)
1816                 return ret;
1817
1818         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1819                 const void *hookptr = info->hook_entry[i];
1820                 if (info->hook_entry[i] &&
1821                     (e < (struct ebt_entry *)(base - hookptr))) {
1822                         newinfo->hook_entry[i] -= off;
1823                         pr_debug("0x%08X -> 0x%08X\n",
1824                                         newinfo->hook_entry[i] + off,
1825                                         newinfo->hook_entry[i]);
1826                 }
1827         }
1828
1829         return 0;
1830 }
1831
1832
1833 static int compat_table_info(const struct ebt_table_info *info,
1834                              struct compat_ebt_replace *newinfo)
1835 {
1836         unsigned int size = info->entries_size;
1837         const void *entries = info->entries;
1838
1839         newinfo->entries_size = size;
1840         if (info->nentries) {
1841                 int ret = xt_compat_init_offsets(NFPROTO_BRIDGE,
1842                                                  info->nentries);
1843                 if (ret)
1844                         return ret;
1845         }
1846
1847         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1848                                                         entries, newinfo);
1849 }
1850
1851 static int compat_copy_everything_to_user(struct ebt_table *t,
1852                                           void __user *user, int *len, int cmd)
1853 {
1854         struct compat_ebt_replace repl, tmp;
1855         struct ebt_counter *oldcounters;
1856         struct ebt_table_info tinfo;
1857         int ret;
1858         void __user *pos;
1859
1860         memset(&tinfo, 0, sizeof(tinfo));
1861
1862         if (cmd == EBT_SO_GET_ENTRIES) {
1863                 tinfo.entries_size = t->private->entries_size;
1864                 tinfo.nentries = t->private->nentries;
1865                 tinfo.entries = t->private->entries;
1866                 oldcounters = t->private->counters;
1867         } else {
1868                 tinfo.entries_size = t->table->entries_size;
1869                 tinfo.nentries = t->table->nentries;
1870                 tinfo.entries = t->table->entries;
1871                 oldcounters = t->table->counters;
1872         }
1873
1874         if (copy_from_user(&tmp, user, sizeof(tmp)))
1875                 return -EFAULT;
1876
1877         if (tmp.nentries != tinfo.nentries ||
1878            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1879                 return -EINVAL;
1880
1881         memcpy(&repl, &tmp, sizeof(repl));
1882         if (cmd == EBT_SO_GET_ENTRIES)
1883                 ret = compat_table_info(t->private, &repl);
1884         else
1885                 ret = compat_table_info(&tinfo, &repl);
1886         if (ret)
1887                 return ret;
1888
1889         if (*len != sizeof(tmp) + repl.entries_size +
1890            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1891                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1892                                 *len, tinfo.entries_size, repl.entries_size);
1893                 return -EINVAL;
1894         }
1895
1896         /* userspace might not need the counters */
1897         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1898                                         tmp.num_counters, tinfo.nentries);
1899         if (ret)
1900                 return ret;
1901
1902         pos = compat_ptr(tmp.entries);
1903         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1904                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1905 }
1906
1907 struct ebt_entries_buf_state {
1908         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1909         u32 buf_kern_len;       /* total size of kernel buffer */
1910         u32 buf_kern_offset;    /* amount of data copied so far */
1911         u32 buf_user_offset;    /* read position in userspace buffer */
1912 };
1913
1914 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1915 {
1916         state->buf_kern_offset += sz;
1917         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1918 }
1919
1920 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1921                        void *data, unsigned int sz)
1922 {
1923         if (state->buf_kern_start == NULL)
1924                 goto count_only;
1925
1926         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1927                 return -EINVAL;
1928
1929         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1930
1931  count_only:
1932         state->buf_user_offset += sz;
1933         return ebt_buf_count(state, sz);
1934 }
1935
1936 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1937 {
1938         char *b = state->buf_kern_start;
1939
1940         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1941                 return -EINVAL;
1942
1943         if (b != NULL && sz > 0)
1944                 memset(b + state->buf_kern_offset, 0, sz);
1945         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1946         return ebt_buf_count(state, sz);
1947 }
1948
1949 enum compat_mwt {
1950         EBT_COMPAT_MATCH,
1951         EBT_COMPAT_WATCHER,
1952         EBT_COMPAT_TARGET,
1953 };
1954
1955 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1956                                 enum compat_mwt compat_mwt,
1957                                 struct ebt_entries_buf_state *state,
1958                                 const unsigned char *base)
1959 {
1960         char name[EBT_EXTENSION_MAXNAMELEN];
1961         struct xt_match *match;
1962         struct xt_target *wt;
1963         void *dst = NULL;
1964         int off, pad = 0;
1965         unsigned int size_kern, match_size = mwt->match_size;
1966
1967         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1968                 return -EINVAL;
1969
1970         if (state->buf_kern_start)
1971                 dst = state->buf_kern_start + state->buf_kern_offset;
1972
1973         switch (compat_mwt) {
1974         case EBT_COMPAT_MATCH:
1975                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1976                                               mwt->u.revision);
1977                 if (IS_ERR(match))
1978                         return PTR_ERR(match);
1979
1980                 off = ebt_compat_match_offset(match, match_size);
1981                 if (dst) {
1982                         if (match->compat_from_user)
1983                                 match->compat_from_user(dst, mwt->data);
1984                         else
1985                                 memcpy(dst, mwt->data, match_size);
1986                 }
1987
1988                 size_kern = match->matchsize;
1989                 if (unlikely(size_kern == -1))
1990                         size_kern = match_size;
1991                 module_put(match->me);
1992                 break;
1993         case EBT_COMPAT_WATCHER: /* fallthrough */
1994         case EBT_COMPAT_TARGET:
1995                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1996                                             mwt->u.revision);
1997                 if (IS_ERR(wt))
1998                         return PTR_ERR(wt);
1999                 off = xt_compat_target_offset(wt);
2000
2001                 if (dst) {
2002                         if (wt->compat_from_user)
2003                                 wt->compat_from_user(dst, mwt->data);
2004                         else
2005                                 memcpy(dst, mwt->data, match_size);
2006                 }
2007
2008                 size_kern = wt->targetsize;
2009                 module_put(wt->me);
2010                 break;
2011
2012         default:
2013                 return -EINVAL;
2014         }
2015
2016         state->buf_kern_offset += match_size + off;
2017         state->buf_user_offset += match_size;
2018         pad = XT_ALIGN(size_kern) - size_kern;
2019
2020         if (pad > 0 && dst) {
2021                 if (WARN_ON(state->buf_kern_len <= pad))
2022                         return -EINVAL;
2023                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2024                         return -EINVAL;
2025                 memset(dst + size_kern, 0, pad);
2026         }
2027         return off + match_size;
2028 }
2029
2030 /* return size of all matches, watchers or target, including necessary
2031  * alignment and padding.
2032  */
2033 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2034                         unsigned int size_left, enum compat_mwt type,
2035                         struct ebt_entries_buf_state *state, const void *base)
2036 {
2037         int growth = 0;
2038         char *buf;
2039
2040         if (size_left == 0)
2041                 return 0;
2042
2043         buf = (char *) match32;
2044
2045         while (size_left >= sizeof(*match32)) {
2046                 struct ebt_entry_match *match_kern;
2047                 int ret;
2048
2049                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2050                 if (match_kern) {
2051                         char *tmp;
2052                         tmp = state->buf_kern_start + state->buf_kern_offset;
2053                         match_kern = (struct ebt_entry_match *) tmp;
2054                 }
2055                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2056                 if (ret < 0)
2057                         return ret;
2058                 size_left -= sizeof(*match32);
2059
2060                 /* add padding before match->data (if any) */
2061                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2062                 if (ret < 0)
2063                         return ret;
2064
2065                 if (match32->match_size > size_left)
2066                         return -EINVAL;
2067
2068                 size_left -= match32->match_size;
2069
2070                 ret = compat_mtw_from_user(match32, type, state, base);
2071                 if (ret < 0)
2072                         return ret;
2073
2074                 if (WARN_ON(ret < match32->match_size))
2075                         return -EINVAL;
2076                 growth += ret - match32->match_size;
2077                 growth += ebt_compat_entry_padsize();
2078
2079                 buf += sizeof(*match32);
2080                 buf += match32->match_size;
2081
2082                 if (match_kern)
2083                         match_kern->match_size = ret;
2084
2085                 if (WARN_ON(type == EBT_COMPAT_TARGET && size_left))
2086                         return -EINVAL;
2087
2088                 match32 = (struct compat_ebt_entry_mwt *) buf;
2089         }
2090
2091         return growth;
2092 }
2093
2094 /* called for all ebt_entry structures. */
2095 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2096                           unsigned int *total,
2097                           struct ebt_entries_buf_state *state)
2098 {
2099         unsigned int i, j, startoff, new_offset = 0;
2100         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2101         unsigned int offsets[4];
2102         unsigned int *offsets_update = NULL;
2103         int ret;
2104         char *buf_start;
2105
2106         if (*total < sizeof(struct ebt_entries))
2107                 return -EINVAL;
2108
2109         if (!entry->bitmask) {
2110                 *total -= sizeof(struct ebt_entries);
2111                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2112         }
2113         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2114                 return -EINVAL;
2115
2116         startoff = state->buf_user_offset;
2117         /* pull in most part of ebt_entry, it does not need to be changed. */
2118         ret = ebt_buf_add(state, entry,
2119                         offsetof(struct ebt_entry, watchers_offset));
2120         if (ret < 0)
2121                 return ret;
2122
2123         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2124         memcpy(&offsets[1], &entry->watchers_offset,
2125                         sizeof(offsets) - sizeof(offsets[0]));
2126
2127         if (state->buf_kern_start) {
2128                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2129                 offsets_update = (unsigned int *) buf_start;
2130         }
2131         ret = ebt_buf_add(state, &offsets[1],
2132                         sizeof(offsets) - sizeof(offsets[0]));
2133         if (ret < 0)
2134                 return ret;
2135         buf_start = (char *) entry;
2136         /* 0: matches offset, always follows ebt_entry.
2137          * 1: watchers offset, from ebt_entry structure
2138          * 2: target offset, from ebt_entry structure
2139          * 3: next ebt_entry offset, from ebt_entry structure
2140          *
2141          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2142          */
2143         for (i = 0; i < 4 ; ++i) {
2144                 if (offsets[i] > *total)
2145                         return -EINVAL;
2146
2147                 if (i < 3 && offsets[i] == *total)
2148                         return -EINVAL;
2149
2150                 if (i == 0)
2151                         continue;
2152                 if (offsets[i-1] > offsets[i])
2153                         return -EINVAL;
2154         }
2155
2156         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2157                 struct compat_ebt_entry_mwt *match32;
2158                 unsigned int size;
2159                 char *buf = buf_start + offsets[i];
2160
2161                 if (offsets[i] > offsets[j])
2162                         return -EINVAL;
2163
2164                 match32 = (struct compat_ebt_entry_mwt *) buf;
2165                 size = offsets[j] - offsets[i];
2166                 ret = ebt_size_mwt(match32, size, i, state, base);
2167                 if (ret < 0)
2168                         return ret;
2169                 new_offset += ret;
2170                 if (offsets_update && new_offset) {
2171                         pr_debug("change offset %d to %d\n",
2172                                 offsets_update[i], offsets[j] + new_offset);
2173                         offsets_update[i] = offsets[j] + new_offset;
2174                 }
2175         }
2176
2177         if (state->buf_kern_start == NULL) {
2178                 unsigned int offset = buf_start - (char *) base;
2179
2180                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2181                 if (ret < 0)
2182                         return ret;
2183         }
2184
2185         startoff = state->buf_user_offset - startoff;
2186
2187         if (WARN_ON(*total < startoff))
2188                 return -EINVAL;
2189         *total -= startoff;
2190         return 0;
2191 }
2192
2193 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2194  * It might need more memory when copied to a 64 bit kernel in case
2195  * userspace is 32-bit. So, first task: find out how much memory is needed.
2196  *
2197  * Called before validation is performed.
2198  */
2199 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2200                                 struct ebt_entries_buf_state *state)
2201 {
2202         unsigned int size_remaining = size_user;
2203         int ret;
2204
2205         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2206                                         &size_remaining, state);
2207         if (ret < 0)
2208                 return ret;
2209
2210         WARN_ON(size_remaining);
2211         return state->buf_kern_offset;
2212 }
2213
2214
2215 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2216                                             void __user *user, unsigned int len)
2217 {
2218         struct compat_ebt_replace tmp;
2219         int i;
2220
2221         if (len < sizeof(tmp))
2222                 return -EINVAL;
2223
2224         if (copy_from_user(&tmp, user, sizeof(tmp)))
2225                 return -EFAULT;
2226
2227         if (len != sizeof(tmp) + tmp.entries_size)
2228                 return -EINVAL;
2229
2230         if (tmp.entries_size == 0)
2231                 return -EINVAL;
2232
2233         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2234                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2235                 return -ENOMEM;
2236         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2237                 return -ENOMEM;
2238
2239         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2240
2241         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2242         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2243                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2244
2245         repl->num_counters = tmp.num_counters;
2246         repl->counters = compat_ptr(tmp.counters);
2247         repl->entries = compat_ptr(tmp.entries);
2248         return 0;
2249 }
2250
2251 static int compat_do_replace(struct net *net, void __user *user,
2252                              unsigned int len)
2253 {
2254         int ret, i, countersize, size64;
2255         struct ebt_table_info *newinfo;
2256         struct ebt_replace tmp;
2257         struct ebt_entries_buf_state state;
2258         void *entries_tmp;
2259
2260         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2261         if (ret) {
2262                 /* try real handler in case userland supplied needed padding */
2263                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2264                         ret = 0;
2265                 return ret;
2266         }
2267
2268         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2269         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2270         if (!newinfo)
2271                 return -ENOMEM;
2272
2273         if (countersize)
2274                 memset(newinfo->counters, 0, countersize);
2275
2276         memset(&state, 0, sizeof(state));
2277
2278         newinfo->entries = vmalloc(tmp.entries_size);
2279         if (!newinfo->entries) {
2280                 ret = -ENOMEM;
2281                 goto free_newinfo;
2282         }
2283         if (copy_from_user(
2284            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2285                 ret = -EFAULT;
2286                 goto free_entries;
2287         }
2288
2289         entries_tmp = newinfo->entries;
2290
2291         xt_compat_lock(NFPROTO_BRIDGE);
2292
2293         ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2294         if (ret < 0)
2295                 goto out_unlock;
2296         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2297         if (ret < 0)
2298                 goto out_unlock;
2299
2300         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2301                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2302                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2303
2304         size64 = ret;
2305         newinfo->entries = vmalloc(size64);
2306         if (!newinfo->entries) {
2307                 vfree(entries_tmp);
2308                 ret = -ENOMEM;
2309                 goto out_unlock;
2310         }
2311
2312         memset(&state, 0, sizeof(state));
2313         state.buf_kern_start = newinfo->entries;
2314         state.buf_kern_len = size64;
2315
2316         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2317         if (WARN_ON(ret < 0))
2318                 goto out_unlock;
2319
2320         vfree(entries_tmp);
2321         tmp.entries_size = size64;
2322
2323         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2324                 char __user *usrptr;
2325                 if (tmp.hook_entry[i]) {
2326                         unsigned int delta;
2327                         usrptr = (char __user *) tmp.hook_entry[i];
2328                         delta = usrptr - tmp.entries;
2329                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2330                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2331                 }
2332         }
2333
2334         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2335         xt_compat_unlock(NFPROTO_BRIDGE);
2336
2337         ret = do_replace_finish(net, &tmp, newinfo);
2338         if (ret == 0)
2339                 return ret;
2340 free_entries:
2341         vfree(newinfo->entries);
2342 free_newinfo:
2343         vfree(newinfo);
2344         return ret;
2345 out_unlock:
2346         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2347         xt_compat_unlock(NFPROTO_BRIDGE);
2348         goto free_entries;
2349 }
2350
2351 static int compat_update_counters(struct net *net, void __user *user,
2352                                   unsigned int len)
2353 {
2354         struct compat_ebt_replace hlp;
2355
2356         if (copy_from_user(&hlp, user, sizeof(hlp)))
2357                 return -EFAULT;
2358
2359         /* try real handler in case userland supplied needed padding */
2360         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2361                 return update_counters(net, user, len);
2362
2363         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2364                                         hlp.num_counters, user, len);
2365 }
2366
2367 static int compat_do_ebt_set_ctl(struct sock *sk,
2368                 int cmd, void __user *user, unsigned int len)
2369 {
2370         int ret;
2371         struct net *net = sock_net(sk);
2372
2373         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2374                 return -EPERM;
2375
2376         switch (cmd) {
2377         case EBT_SO_SET_ENTRIES:
2378                 ret = compat_do_replace(net, user, len);
2379                 break;
2380         case EBT_SO_SET_COUNTERS:
2381                 ret = compat_update_counters(net, user, len);
2382                 break;
2383         default:
2384                 ret = -EINVAL;
2385         }
2386         return ret;
2387 }
2388
2389 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2390                 void __user *user, int *len)
2391 {
2392         int ret;
2393         struct compat_ebt_replace tmp;
2394         struct ebt_table *t;
2395         struct net *net = sock_net(sk);
2396
2397         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2398                 return -EPERM;
2399
2400         /* try real handler in case userland supplied needed padding */
2401         if ((cmd == EBT_SO_GET_INFO ||
2402              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2403                         return do_ebt_get_ctl(sk, cmd, user, len);
2404
2405         if (copy_from_user(&tmp, user, sizeof(tmp)))
2406                 return -EFAULT;
2407
2408         tmp.name[sizeof(tmp.name) - 1] = '\0';
2409
2410         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2411         if (!t)
2412                 return ret;
2413
2414         xt_compat_lock(NFPROTO_BRIDGE);
2415         switch (cmd) {
2416         case EBT_SO_GET_INFO:
2417                 tmp.nentries = t->private->nentries;
2418                 ret = compat_table_info(t->private, &tmp);
2419                 if (ret)
2420                         goto out;
2421                 tmp.valid_hooks = t->valid_hooks;
2422
2423                 if (copy_to_user(user, &tmp, *len) != 0) {
2424                         ret = -EFAULT;
2425                         break;
2426                 }
2427                 ret = 0;
2428                 break;
2429         case EBT_SO_GET_INIT_INFO:
2430                 tmp.nentries = t->table->nentries;
2431                 tmp.entries_size = t->table->entries_size;
2432                 tmp.valid_hooks = t->table->valid_hooks;
2433
2434                 if (copy_to_user(user, &tmp, *len) != 0) {
2435                         ret = -EFAULT;
2436                         break;
2437                 }
2438                 ret = 0;
2439                 break;
2440         case EBT_SO_GET_ENTRIES:
2441         case EBT_SO_GET_INIT_ENTRIES:
2442                 /* try real handler first in case of userland-side padding.
2443                  * in case we are dealing with an 'ordinary' 32 bit binary
2444                  * without 64bit compatibility padding, this will fail right
2445                  * after copy_from_user when the *len argument is validated.
2446                  *
2447                  * the compat_ variant needs to do one pass over the kernel
2448                  * data set to adjust for size differences before it the check.
2449                  */
2450                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2451                         ret = 0;
2452                 else
2453                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2454                 break;
2455         default:
2456                 ret = -EINVAL;
2457         }
2458  out:
2459         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2460         xt_compat_unlock(NFPROTO_BRIDGE);
2461         mutex_unlock(&ebt_mutex);
2462         return ret;
2463 }
2464 #endif
2465
2466 static struct nf_sockopt_ops ebt_sockopts = {
2467         .pf             = PF_INET,
2468         .set_optmin     = EBT_BASE_CTL,
2469         .set_optmax     = EBT_SO_SET_MAX + 1,
2470         .set            = do_ebt_set_ctl,
2471 #ifdef CONFIG_COMPAT
2472         .compat_set     = compat_do_ebt_set_ctl,
2473 #endif
2474         .get_optmin     = EBT_BASE_CTL,
2475         .get_optmax     = EBT_SO_GET_MAX + 1,
2476         .get            = do_ebt_get_ctl,
2477 #ifdef CONFIG_COMPAT
2478         .compat_get     = compat_do_ebt_get_ctl,
2479 #endif
2480         .owner          = THIS_MODULE,
2481 };
2482
2483 static int __init ebtables_init(void)
2484 {
2485         int ret;
2486
2487         ret = xt_register_target(&ebt_standard_target);
2488         if (ret < 0)
2489                 return ret;
2490         ret = nf_register_sockopt(&ebt_sockopts);
2491         if (ret < 0) {
2492                 xt_unregister_target(&ebt_standard_target);
2493                 return ret;
2494         }
2495
2496         return 0;
2497 }
2498
2499 static void __exit ebtables_fini(void)
2500 {
2501         nf_unregister_sockopt(&ebt_sockopts);
2502         xt_unregister_target(&ebt_standard_target);
2503 }
2504
2505 EXPORT_SYMBOL(ebt_register_table);
2506 EXPORT_SYMBOL(ebt_unregister_table);
2507 EXPORT_SYMBOL(ebt_do_table);
2508 module_init(ebtables_init);
2509 module_exit(ebtables_fini);
2510 MODULE_LICENSE("GPL");