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