net/bridge/netfilter/ebtables.c

   1 /*
   2  *  ebtables
   3  *
   4  *  Author:
   5  *  Bart De Schuymer            <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, July, 2002
   8  *
   9  *  This code is strongly inspired by the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  *
  12  *  This program is free software; you can redistribute it and/or
  13  *  modify it under the terms of the GNU General Public License
  14  *  as published by the Free Software Foundation; either version
  15  *  2 of the License, or (at your option) any later version.
  16  */
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18 #include <linux/kmod.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/netfilter/x_tables.h>
  22 #include <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/smp.h>
  28 #include <linux/cpumask.h>
  29 #include <linux/audit.h>
  30 #include <net/sock.h>
  31 /* needed for logical [in,out]-dev filtering */
  32 #include "../br_private.h"
  33
  34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
  35                                          "report to author: "format, ## args)
  36 /* #define BUGPRINT(format, args...) */
  37
  38 /* Each cpu has its own set of counters, so there is no need for write_lock in
  39  * the softirq
  40  * For reading or updating the counters, the user context needs to
  41  * get a write_lock
  42  */
  43
  44 /* The size of each set of counters is altered to get cache alignment */
  45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  48                                  COUNTER_OFFSET(n) * cpu))
  49
  50
  51
  52 static DEFINE_MUTEX(ebt_mutex);
  53
  54 #ifdef CONFIG_COMPAT
  55 static void ebt_standard_compat_from_user(void *dst, const void *src)
  56 {
  57         int v = *(compat_int_t *)src;
  58
  59         if (v >= 0)
  60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  61         memcpy(dst, &v, sizeof(v));
  62 }
  63
  64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  65 {
  66         compat_int_t cv = *(int *)src;
  67
  68         if (cv >= 0)
  69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  71 }
  72 #endif
  73
  74
  75 static struct xt_target ebt_standard_target = {
  76         .name       = "standard",
  77         .revision   = 0,
  78         .family     = NFPROTO_BRIDGE,
  79         .targetsize = sizeof(int),
  80 #ifdef CONFIG_COMPAT
  81         .compatsize = sizeof(compat_int_t),
  82         .compat_from_user = ebt_standard_compat_from_user,
  83         .compat_to_user =  ebt_standard_compat_to_user,
  84 #endif
  85 };
  86
  87 static inline int
  88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  89                struct xt_action_param *par)
  90 {
  91         par->target   = w->u.watcher;
  92         par->targinfo = w->data;
  93         w->u.watcher->target(skb, par);
  94         /* watchers don't give a verdict */
  95         return 0;
  96 }
  97
  98 static inline int
  99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 100              struct xt_action_param *par)
 101 {
 102         par->match     = m->u.match;
 103         par->matchinfo = m->data;
 104         return !m->u.match->match(skb, par);
 105 }
 106
 107 static inline int
 108 ebt_dev_check(const char *entry, const struct net_device *device)
 109 {
 110         int i = 0;
 111         const char *devname;
 112
 113         if (*entry == '\0')
 114                 return 0;
 115         if (!device)
 116                 return 1;
 117         devname = device->name;
 118         /* 1 is the wildcard token */
 119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 120                 i++;
 121         return devname[i] != entry[i] && entry[i] != 1;
 122 }
 123
 124 /* process standard matches */
 125 static inline int
 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 127                 const struct net_device *in, const struct net_device *out)
 128 {
 129         const struct ethhdr *h = eth_hdr(skb);
 130         const struct net_bridge_port *p;
 131         __be16 ethproto;
 132
 133         if (skb_vlan_tag_present(skb))
 134                 ethproto = htons(ETH_P_8021Q);
 135         else
 136                 ethproto = h->h_proto;
 137
 138         if (e->bitmask & EBT_802_3) {
 139                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 140                         return 1;
 141         } else if (!(e->bitmask & EBT_NOPROTO) &&
 142                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 143                 return 1;
 144
 145         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 146                 return 1;
 147         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 148                 return 1;
 149         /* rcu_read_lock()ed by nf_hook_thresh */
 150         if (in && (p = br_port_get_rcu(in)) != NULL &&
 151             NF_INVF(e, EBT_ILOGICALIN,
 152                     ebt_dev_check(e->logical_in, p->br->dev)))
 153                 return 1;
 154         if (out && (p = br_port_get_rcu(out)) != NULL &&
 155             NF_INVF(e, EBT_ILOGICALOUT,
 156                     ebt_dev_check(e->logical_out, p->br->dev)))
 157                 return 1;
 158
 159         if (e->bitmask & EBT_SOURCEMAC) {
 160                 if (NF_INVF(e, EBT_ISOURCE,
 161                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
 162                                                      e->sourcemsk)))
 163                         return 1;
 164         }
 165         if (e->bitmask & EBT_DESTMAC) {
 166                 if (NF_INVF(e, EBT_IDEST,
 167                             !ether_addr_equal_masked(h->h_dest, e->destmac,
 168                                                      e->destmsk)))
 169                         return 1;
 170         }
 171         return 0;
 172 }
 173
 174 static inline
 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 176 {
 177         return (void *)entry + entry->next_offset;
 178 }
 179
 180 static inline const struct ebt_entry_target *
 181 ebt_get_target_c(const struct ebt_entry *e)
 182 {
 183         return ebt_get_target((struct ebt_entry *)e);
 184 }
 185
 186 /* Do some firewalling */
 187 unsigned int ebt_do_table(struct sk_buff *skb,
 188                           const struct nf_hook_state *state,
 189                           struct ebt_table *table)
 190 {
 191         unsigned int hook = state->hook;
 192         int i, nentries;
 193         struct ebt_entry *point;
 194         struct ebt_counter *counter_base, *cb_base;
 195         const struct ebt_entry_target *t;
 196         int verdict, sp = 0;
 197         struct ebt_chainstack *cs;
 198         struct ebt_entries *chaininfo;
 199         const char *base;
 200         const struct ebt_table_info *private;
 201         struct xt_action_param acpar;
 202
 203         acpar.state   = state;
 204         acpar.hotdrop = false;
 205
 206         read_lock_bh(&table->lock);
 207         private = table->private;
 208         cb_base = COUNTER_BASE(private->counters, private->nentries,
 209            smp_processor_id());
 210         if (private->chainstack)
 211                 cs = private->chainstack[smp_processor_id()];
 212         else
 213                 cs = NULL;
 214         chaininfo = private->hook_entry[hook];
 215         nentries = private->hook_entry[hook]->nentries;
 216         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 217         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 218         /* base for chain jumps */
 219         base = private->entries;
 220         i = 0;
 221         while (i < nentries) {
 222                 if (ebt_basic_match(point, skb, state->in, state->out))
 223                         goto letscontinue;
 224
 225                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 226                         goto letscontinue;
 227                 if (acpar.hotdrop) {
 228                         read_unlock_bh(&table->lock);
 229                         return NF_DROP;
 230                 }
 231
 232                 ADD_COUNTER(*(counter_base + i), 1, skb->len);
 233
 234                 /* these should only watch: not modify, nor tell us
 235                  * what to do with the packet
 236                  */
 237                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 238
 239                 t = ebt_get_target_c(point);
 240                 /* standard target */
 241                 if (!t->u.target->target)
 242                         verdict = ((struct ebt_standard_target *)t)->verdict;
 243                 else {
 244                         acpar.target   = t->u.target;
 245                         acpar.targinfo = t->data;
 246                         verdict = t->u.target->target(skb, &acpar);
 247                 }
 248                 if (verdict == EBT_ACCEPT) {
 249                         read_unlock_bh(&table->lock);
 250                         return NF_ACCEPT;
 251                 }
 252                 if (verdict == EBT_DROP) {
 253                         read_unlock_bh(&table->lock);
 254                         return NF_DROP;
 255                 }
 256                 if (verdict == EBT_RETURN) {
 257 letsreturn:
 258                         if (WARN(sp == 0, "RETURN on base chain")) {
 259                                 /* act like this is EBT_CONTINUE */
 260                                 goto letscontinue;
 261                         }
 262
 263                         sp--;
 264                         /* put all the local variables right */
 265                         i = cs[sp].n;
 266                         chaininfo = cs[sp].chaininfo;
 267                         nentries = chaininfo->nentries;
 268                         point = cs[sp].e;
 269                         counter_base = cb_base +
 270                            chaininfo->counter_offset;
 271                         continue;
 272                 }
 273                 if (verdict == EBT_CONTINUE)
 274                         goto letscontinue;
 275
 276                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
 277                         read_unlock_bh(&table->lock);
 278                         return NF_DROP;
 279                 }
 280
 281                 /* jump to a udc */
 282                 cs[sp].n = i + 1;
 283                 cs[sp].chaininfo = chaininfo;
 284                 cs[sp].e = ebt_next_entry(point);
 285                 i = 0;
 286                 chaininfo = (struct ebt_entries *) (base + verdict);
 287
 288                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 289                         read_unlock_bh(&table->lock);
 290                         return NF_DROP;
 291                 }
 292
 293                 nentries = chaininfo->nentries;
 294                 point = (struct ebt_entry *)chaininfo->data;
 295                 counter_base = cb_base + chaininfo->counter_offset;
 296                 sp++;
 297                 continue;
 298 letscontinue:
 299                 point = ebt_next_entry(point);
 300                 i++;
 301         }
 302
 303         /* I actually like this :) */
 304         if (chaininfo->policy == EBT_RETURN)
 305                 goto letsreturn;
 306         if (chaininfo->policy == EBT_ACCEPT) {
 307                 read_unlock_bh(&table->lock);
 308                 return NF_ACCEPT;
 309         }
 310         read_unlock_bh(&table->lock);
 311         return NF_DROP;
 312 }
 313
 314 /* If it succeeds, returns element and locks mutex */
 315 static inline void *
 316 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 317                         struct mutex *mutex)
 318 {
 319         struct {
 320                 struct list_head list;
 321                 char name[EBT_FUNCTION_MAXNAMELEN];
 322         } *e;
 323
 324         mutex_lock(mutex);
 325         list_for_each_entry(e, head, list) {
 326                 if (strcmp(e->name, name) == 0)
 327                         return e;
 328         }
 329         *error = -ENOENT;
 330         mutex_unlock(mutex);
 331         return NULL;
 332 }
 333
 334 static void *
 335 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 336                  int *error, struct mutex *mutex)
 337 {
 338         return try_then_request_module(
 339                         find_inlist_lock_noload(head, name, error, mutex),
 340                         "%s%s", prefix, name);
 341 }
 342
 343 static inline struct ebt_table *
 344 find_table_lock(struct net *net, const char *name, int *error,
 345                 struct mutex *mutex)
 346 {
 347         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 348                                 "ebtable_", error, mutex);
 349 }
 350
 351 static inline void ebt_free_table_info(struct ebt_table_info *info)
 352 {
 353         int i;
 354
 355         if (info->chainstack) {
 356                 for_each_possible_cpu(i)
 357                         vfree(info->chainstack[i]);
 358                 vfree(info->chainstack);
 359         }
 360 }
 361 static inline int
 362 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 363                 unsigned int *cnt)
 364 {
 365         const struct ebt_entry *e = par->entryinfo;
 366         struct xt_match *match;
 367         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 368         int ret;
 369
 370         if (left < sizeof(struct ebt_entry_match) ||
 371             left - sizeof(struct ebt_entry_match) < m->match_size)
 372                 return -EINVAL;
 373
 374         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 375         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 376                 if (!IS_ERR(match))
 377                         module_put(match->me);
 378                 request_module("ebt_%s", m->u.name);
 379                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 380         }
 381         if (IS_ERR(match))
 382                 return PTR_ERR(match);
 383         m->u.match = match;
 384
 385         par->match     = match;
 386         par->matchinfo = m->data;
 387         ret = xt_check_match(par, m->match_size,
 388               e->ethproto, e->invflags & EBT_IPROTO);
 389         if (ret < 0) {
 390                 module_put(match->me);
 391                 return ret;
 392         }
 393
 394         (*cnt)++;
 395         return 0;
 396 }
 397
 398 static inline int
 399 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 400                   unsigned int *cnt)
 401 {
 402         const struct ebt_entry *e = par->entryinfo;
 403         struct xt_target *watcher;
 404         size_t left = ((char *)e + e->target_offset) - (char *)w;
 405         int ret;
 406
 407         if (left < sizeof(struct ebt_entry_watcher) ||
 408            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 409                 return -EINVAL;
 410
 411         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 412         if (IS_ERR(watcher))
 413                 return PTR_ERR(watcher);
 414
 415         if (watcher->family != NFPROTO_BRIDGE) {
 416                 module_put(watcher->me);
 417                 return -ENOENT;
 418         }
 419
 420         w->u.watcher = watcher;
 421
 422         par->target   = watcher;
 423         par->targinfo = w->data;
 424         ret = xt_check_target(par, w->watcher_size,
 425               e->ethproto, e->invflags & EBT_IPROTO);
 426         if (ret < 0) {
 427                 module_put(watcher->me);
 428                 return ret;
 429         }
 430
 431         (*cnt)++;
 432         return 0;
 433 }
 434
 435 static int ebt_verify_pointers(const struct ebt_replace *repl,
 436                                struct ebt_table_info *newinfo)
 437 {
 438         unsigned int limit = repl->entries_size;
 439         unsigned int valid_hooks = repl->valid_hooks;
 440         unsigned int offset = 0;
 441         int i;
 442
 443         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 444                 newinfo->hook_entry[i] = NULL;
 445
 446         newinfo->entries_size = repl->entries_size;
 447         newinfo->nentries = repl->nentries;
 448
 449         while (offset < limit) {
 450                 size_t left = limit - offset;
 451                 struct ebt_entry *e = (void *)newinfo->entries + offset;
 452
 453                 if (left < sizeof(unsigned int))
 454                         break;
 455
 456                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 457                         if ((valid_hooks & (1 << i)) == 0)
 458                                 continue;
 459                         if ((char __user *)repl->hook_entry[i] ==
 460                              repl->entries + offset)
 461                                 break;
 462                 }
 463
 464                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 465                         if (e->bitmask != 0) {
 466                                 /* we make userspace set this right,
 467                                  * so there is no misunderstanding
 468                                  */
 469                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
 470                                          "in distinguisher\n");
 471                                 return -EINVAL;
 472                         }
 473                         if (i != NF_BR_NUMHOOKS)
 474                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
 475                         if (left < sizeof(struct ebt_entries))
 476                                 break;
 477                         offset += sizeof(struct ebt_entries);
 478                 } else {
 479                         if (left < sizeof(struct ebt_entry))
 480                                 break;
 481                         if (left < e->next_offset)
 482                                 break;
 483                         if (e->next_offset < sizeof(struct ebt_entry))
 484                                 return -EINVAL;
 485                         offset += e->next_offset;
 486                 }
 487         }
 488         if (offset != limit) {
 489                 BUGPRINT("entries_size too small\n");
 490                 return -EINVAL;
 491         }
 492
 493         /* check if all valid hooks have a chain */
 494         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 495                 if (!newinfo->hook_entry[i] &&
 496                    (valid_hooks & (1 << i))) {
 497                         BUGPRINT("Valid hook without chain\n");
 498                         return -EINVAL;
 499                 }
 500         }
 501         return 0;
 502 }
 503
 504 /* this one is very careful, as it is the first function
 505  * to parse the userspace data
 506  */
 507 static inline int
 508 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 509                                const struct ebt_table_info *newinfo,
 510                                unsigned int *n, unsigned int *cnt,
 511                                unsigned int *totalcnt, unsigned int *udc_cnt)
 512 {
 513         int i;
 514
 515         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 516                 if ((void *)e == (void *)newinfo->hook_entry[i])
 517                         break;
 518         }
 519         /* beginning of a new chain
 520          * if i == NF_BR_NUMHOOKS it must be a user defined chain
 521          */
 522         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 523                 /* this checks if the previous chain has as many entries
 524                  * as it said it has
 525                  */
 526                 if (*n != *cnt) {
 527                         BUGPRINT("nentries does not equal the nr of entries "
 528                                  "in the chain\n");
 529                         return -EINVAL;
 530                 }
 531                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 532                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 533                         /* only RETURN from udc */
 534                         if (i != NF_BR_NUMHOOKS ||
 535                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
 536                                 BUGPRINT("bad policy\n");
 537                                 return -EINVAL;
 538                         }
 539                 }
 540                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 541                         (*udc_cnt)++;
 542                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
 543                         BUGPRINT("counter_offset != totalcnt");
 544                         return -EINVAL;
 545                 }
 546                 *n = ((struct ebt_entries *)e)->nentries;
 547                 *cnt = 0;
 548                 return 0;
 549         }
 550         /* a plain old entry, heh */
 551         if (sizeof(struct ebt_entry) > e->watchers_offset ||
 552            e->watchers_offset > e->target_offset ||
 553            e->target_offset >= e->next_offset) {
 554                 BUGPRINT("entry offsets not in right order\n");
 555                 return -EINVAL;
 556         }
 557         /* this is not checked anywhere else */
 558         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
 559                 BUGPRINT("target size too small\n");
 560                 return -EINVAL;
 561         }
 562         (*cnt)++;
 563         (*totalcnt)++;
 564         return 0;
 565 }
 566
 567 struct ebt_cl_stack {
 568         struct ebt_chainstack cs;
 569         int from;
 570         unsigned int hookmask;
 571 };
 572
 573 /* We need these positions to check that the jumps to a different part of the
 574  * entries is a jump to the beginning of a new chain.
 575  */
 576 static inline int
 577 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 578                       unsigned int *n, struct ebt_cl_stack *udc)
 579 {
 580         int i;
 581
 582         /* we're only interested in chain starts */
 583         if (e->bitmask)
 584                 return 0;
 585         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 586                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 587                         break;
 588         }
 589         /* only care about udc */
 590         if (i != NF_BR_NUMHOOKS)
 591                 return 0;
 592
 593         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 594         /* these initialisations are depended on later in check_chainloops() */
 595         udc[*n].cs.n = 0;
 596         udc[*n].hookmask = 0;
 597
 598         (*n)++;
 599         return 0;
 600 }
 601
 602 static inline int
 603 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 604 {
 605         struct xt_mtdtor_param par;
 606
 607         if (i && (*i)-- == 0)
 608                 return 1;
 609
 610         par.net       = net;
 611         par.match     = m->u.match;
 612         par.matchinfo = m->data;
 613         par.family    = NFPROTO_BRIDGE;
 614         if (par.match->destroy != NULL)
 615                 par.match->destroy(&par);
 616         module_put(par.match->me);
 617         return 0;
 618 }
 619
 620 static inline int
 621 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 622 {
 623         struct xt_tgdtor_param par;
 624
 625         if (i && (*i)-- == 0)
 626                 return 1;
 627
 628         par.net      = net;
 629         par.target   = w->u.watcher;
 630         par.targinfo = w->data;
 631         par.family   = NFPROTO_BRIDGE;
 632         if (par.target->destroy != NULL)
 633                 par.target->destroy(&par);
 634         module_put(par.target->me);
 635         return 0;
 636 }
 637
 638 static inline int
 639 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 640 {
 641         struct xt_tgdtor_param par;
 642         struct ebt_entry_target *t;
 643
 644         if (e->bitmask == 0)
 645                 return 0;
 646         /* we're done */
 647         if (cnt && (*cnt)-- == 0)
 648                 return 1;
 649         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 650         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 651         t = ebt_get_target(e);
 652
 653         par.net      = net;
 654         par.target   = t->u.target;
 655         par.targinfo = t->data;
 656         par.family   = NFPROTO_BRIDGE;
 657         if (par.target->destroy != NULL)
 658                 par.target->destroy(&par);
 659         module_put(par.target->me);
 660         return 0;
 661 }
 662
 663 static inline int
 664 ebt_check_entry(struct ebt_entry *e, struct net *net,
 665                 const struct ebt_table_info *newinfo,
 666                 const char *name, unsigned int *cnt,
 667                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 668 {
 669         struct ebt_entry_target *t;
 670         struct xt_target *target;
 671         unsigned int i, j, hook = 0, hookmask = 0;
 672         size_t gap;
 673         int ret;
 674         struct xt_mtchk_param mtpar;
 675         struct xt_tgchk_param tgpar;
 676
 677         /* don't mess with the struct ebt_entries */
 678         if (e->bitmask == 0)
 679                 return 0;
 680
 681         if (e->bitmask & ~EBT_F_MASK) {
 682                 BUGPRINT("Unknown flag for bitmask\n");
 683                 return -EINVAL;
 684         }
 685         if (e->invflags & ~EBT_INV_MASK) {
 686                 BUGPRINT("Unknown flag for inv bitmask\n");
 687                 return -EINVAL;
 688         }
 689         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
 690                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
 691                 return -EINVAL;
 692         }
 693         /* what hook do we belong to? */
 694         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 695                 if (!newinfo->hook_entry[i])
 696                         continue;
 697                 if ((char *)newinfo->hook_entry[i] < (char *)e)
 698                         hook = i;
 699                 else
 700                         break;
 701         }
 702         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 703          * a base chain
 704          */
 705         if (i < NF_BR_NUMHOOKS)
 706                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 707         else {
 708                 for (i = 0; i < udc_cnt; i++)
 709                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 710                                 break;
 711                 if (i == 0)
 712                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 713                 else
 714                         hookmask = cl_s[i - 1].hookmask;
 715         }
 716         i = 0;
 717
 718         memset(&mtpar, 0, sizeof(mtpar));
 719         memset(&tgpar, 0, sizeof(tgpar));
 720         mtpar.net       = tgpar.net       = net;
 721         mtpar.table     = tgpar.table     = name;
 722         mtpar.entryinfo = tgpar.entryinfo = e;
 723         mtpar.hook_mask = tgpar.hook_mask = hookmask;
 724         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 725         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 726         if (ret != 0)
 727                 goto cleanup_matches;
 728         j = 0;
 729         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 730         if (ret != 0)
 731                 goto cleanup_watchers;
 732         t = ebt_get_target(e);
 733         gap = e->next_offset - e->target_offset;
 734
 735         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 736         if (IS_ERR(target)) {
 737                 ret = PTR_ERR(target);
 738                 goto cleanup_watchers;
 739         }
 740
 741         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
 742         if (target->family != NFPROTO_BRIDGE) {
 743                 module_put(target->me);
 744                 ret = -ENOENT;
 745                 goto cleanup_watchers;
 746         }
 747
 748         t->u.target = target;
 749         if (t->u.target == &ebt_standard_target) {
 750                 if (gap < sizeof(struct ebt_standard_target)) {
 751                         BUGPRINT("Standard target size too big\n");
 752                         ret = -EFAULT;
 753                         goto cleanup_watchers;
 754                 }
 755                 if (((struct ebt_standard_target *)t)->verdict <
 756                    -NUM_STANDARD_TARGETS) {
 757                         BUGPRINT("Invalid standard target\n");
 758                         ret = -EFAULT;
 759                         goto cleanup_watchers;
 760                 }
 761         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 762                 module_put(t->u.target->me);
 763                 ret = -EFAULT;
 764                 goto cleanup_watchers;
 765         }
 766
 767         tgpar.target   = target;
 768         tgpar.targinfo = t->data;
 769         ret = xt_check_target(&tgpar, t->target_size,
 770               e->ethproto, e->invflags & EBT_IPROTO);
 771         if (ret < 0) {
 772                 module_put(target->me);
 773                 goto cleanup_watchers;
 774         }
 775         (*cnt)++;
 776         return 0;
 777 cleanup_watchers:
 778         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 779 cleanup_matches:
 780         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 781         return ret;
 782 }
 783
 784 /* checks for loops and sets the hook mask for udc
 785  * the hook mask for udc tells us from which base chains the udc can be
 786  * accessed. This mask is a parameter to the check() functions of the extensions
 787  */
 788 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 789                             unsigned int udc_cnt, unsigned int hooknr, char *base)
 790 {
 791         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 792         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 793         const struct ebt_entry_target *t;
 794
 795         while (pos < nentries || chain_nr != -1) {
 796                 /* end of udc, go back one 'recursion' step */
 797                 if (pos == nentries) {
 798                         /* put back values of the time when this chain was called */
 799                         e = cl_s[chain_nr].cs.e;
 800                         if (cl_s[chain_nr].from != -1)
 801                                 nentries =
 802                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 803                         else
 804                                 nentries = chain->nentries;
 805                         pos = cl_s[chain_nr].cs.n;
 806                         /* make sure we won't see a loop that isn't one */
 807                         cl_s[chain_nr].cs.n = 0;
 808                         chain_nr = cl_s[chain_nr].from;
 809                         if (pos == nentries)
 810                                 continue;
 811                 }
 812                 t = ebt_get_target_c(e);
 813                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 814                         goto letscontinue;
 815                 if (e->target_offset + sizeof(struct ebt_standard_target) >
 816                    e->next_offset) {
 817                         BUGPRINT("Standard target size too big\n");
 818                         return -1;
 819                 }
 820                 verdict = ((struct ebt_standard_target *)t)->verdict;
 821                 if (verdict >= 0) { /* jump to another chain */
 822                         struct ebt_entries *hlp2 =
 823                            (struct ebt_entries *)(base + verdict);
 824                         for (i = 0; i < udc_cnt; i++)
 825                                 if (hlp2 == cl_s[i].cs.chaininfo)
 826                                         break;
 827                         /* bad destination or loop */
 828                         if (i == udc_cnt) {
 829                                 BUGPRINT("bad destination\n");
 830                                 return -1;
 831                         }
 832                         if (cl_s[i].cs.n) {
 833                                 BUGPRINT("loop\n");
 834                                 return -1;
 835                         }
 836                         if (cl_s[i].hookmask & (1 << hooknr))
 837                                 goto letscontinue;
 838                         /* this can't be 0, so the loop test is correct */
 839                         cl_s[i].cs.n = pos + 1;
 840                         pos = 0;
 841                         cl_s[i].cs.e = ebt_next_entry(e);
 842                         e = (struct ebt_entry *)(hlp2->data);
 843                         nentries = hlp2->nentries;
 844                         cl_s[i].from = chain_nr;
 845                         chain_nr = i;
 846                         /* this udc is accessible from the base chain for hooknr */
 847                         cl_s[i].hookmask |= (1 << hooknr);
 848                         continue;
 849                 }
 850 letscontinue:
 851                 e = ebt_next_entry(e);
 852                 pos++;
 853         }
 854         return 0;
 855 }
 856
 857 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 858 static int translate_table(struct net *net, const char *name,
 859                            struct ebt_table_info *newinfo)
 860 {
 861         unsigned int i, j, k, udc_cnt;
 862         int ret;
 863         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 864
 865         i = 0;
 866         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 867                 i++;
 868         if (i == NF_BR_NUMHOOKS) {
 869                 BUGPRINT("No valid hooks specified\n");
 870                 return -EINVAL;
 871         }
 872         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
 873                 BUGPRINT("Chains don't start at beginning\n");
 874                 return -EINVAL;
 875         }
 876         /* make sure chains are ordered after each other in same order
 877          * as their corresponding hooks
 878          */
 879         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 880                 if (!newinfo->hook_entry[j])
 881                         continue;
 882                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
 883                         BUGPRINT("Hook order must be followed\n");
 884                         return -EINVAL;
 885                 }
 886                 i = j;
 887         }
 888
 889         /* do some early checkings and initialize some things */
 890         i = 0; /* holds the expected nr. of entries for the chain */
 891         j = 0; /* holds the up to now counted entries for the chain */
 892         k = 0; /* holds the total nr. of entries, should equal
 893                 * newinfo->nentries afterwards
 894                 */
 895         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 896         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 897            ebt_check_entry_size_and_hooks, newinfo,
 898            &i, &j, &k, &udc_cnt);
 899
 900         if (ret != 0)
 901                 return ret;
 902
 903         if (i != j) {
 904                 BUGPRINT("nentries does not equal the nr of entries in the "
 905                          "(last) chain\n");
 906                 return -EINVAL;
 907         }
 908         if (k != newinfo->nentries) {
 909                 BUGPRINT("Total nentries is wrong\n");
 910                 return -EINVAL;
 911         }
 912
 913         /* get the location of the udc, put them in an array
 914          * while we're at it, allocate the chainstack
 915          */
 916         if (udc_cnt) {
 917                 /* this will get free'd in do_replace()/ebt_register_table()
 918                  * if an error occurs
 919                  */
 920                 newinfo->chainstack =
 921                         vmalloc(array_size(nr_cpu_ids,
 922                                            sizeof(*(newinfo->chainstack))));
 923                 if (!newinfo->chainstack)
 924                         return -ENOMEM;
 925                 for_each_possible_cpu(i) {
 926                         newinfo->chainstack[i] =
 927                           vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 928                         if (!newinfo->chainstack[i]) {
 929                                 while (i)
 930                                         vfree(newinfo->chainstack[--i]);
 931                                 vfree(newinfo->chainstack);
 932                                 newinfo->chainstack = NULL;
 933                                 return -ENOMEM;
 934                         }
 935                 }
 936
 937                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 938                 if (!cl_s)
 939                         return -ENOMEM;
 940                 i = 0; /* the i'th udc */
 941                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 942                    ebt_get_udc_positions, newinfo, &i, cl_s);
 943                 /* sanity check */
 944                 if (i != udc_cnt) {
 945                         BUGPRINT("i != udc_cnt\n");
 946                         vfree(cl_s);
 947                         return -EFAULT;
 948                 }
 949         }
 950
 951         /* Check for loops */
 952         for (i = 0; i < NF_BR_NUMHOOKS; i++)
 953                 if (newinfo->hook_entry[i])
 954                         if (check_chainloops(newinfo->hook_entry[i],
 955                            cl_s, udc_cnt, i, newinfo->entries)) {
 956                                 vfree(cl_s);
 957                                 return -EINVAL;
 958                         }
 959
 960         /* we now know the following (along with E=mc²):
 961          *  - the nr of entries in each chain is right
 962          *  - the size of the allocated space is right
 963          *  - all valid hooks have a corresponding chain
 964          *  - there are no loops
 965          *  - wrong data can still be on the level of a single entry
 966          *  - could be there are jumps to places that are not the
 967          *    beginning of a chain. This can only occur in chains that
 968          *    are not accessible from any base chains, so we don't care.
 969          */
 970
 971         /* used to know what we need to clean up if something goes wrong */
 972         i = 0;
 973         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 974            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 975         if (ret != 0) {
 976                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 977                                   ebt_cleanup_entry, net, &i);
 978         }
 979         vfree(cl_s);
 980         return ret;
 981 }
 982
 983 /* called under write_lock */
 984 static void get_counters(const struct ebt_counter *oldcounters,
 985                          struct ebt_counter *counters, unsigned int nentries)
 986 {
 987         int i, cpu;
 988         struct ebt_counter *counter_base;
 989
 990         /* counters of cpu 0 */
 991         memcpy(counters, oldcounters,
 992                sizeof(struct ebt_counter) * nentries);
 993
 994         /* add other counters to those of cpu 0 */
 995         for_each_possible_cpu(cpu) {
 996                 if (cpu == 0)
 997                         continue;
 998                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 999                 for (i = 0; i < nentries; i++)
1000                         ADD_COUNTER(counters[i], counter_base[i].pcnt,
1001                                     counter_base[i].bcnt);
1002         }
1003 }
1004
1005 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1006                               struct ebt_table_info *newinfo)
1007 {
1008         int ret;
1009         struct ebt_counter *counterstmp = NULL;
1010         /* used to be able to unlock earlier */
1011         struct ebt_table_info *table;
1012         struct ebt_table *t;
1013
1014         /* the user wants counters back
1015          * the check on the size is done later, when we have the lock
1016          */
1017         if (repl->num_counters) {
1018                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1019                 counterstmp = vmalloc(size);
1020                 if (!counterstmp)
1021                         return -ENOMEM;
1022         }
1023
1024         newinfo->chainstack = NULL;
1025         ret = ebt_verify_pointers(repl, newinfo);
1026         if (ret != 0)
1027                 goto free_counterstmp;
1028
1029         ret = translate_table(net, repl->name, newinfo);
1030
1031         if (ret != 0)
1032                 goto free_counterstmp;
1033
1034         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1035         if (!t) {
1036                 ret = -ENOENT;
1037                 goto free_iterate;
1038         }
1039
1040         /* the table doesn't like it */
1041         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1042                 goto free_unlock;
1043
1044         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1045                 BUGPRINT("Wrong nr. of counters requested\n");
1046                 ret = -EINVAL;
1047                 goto free_unlock;
1048         }
1049
1050         /* we have the mutex lock, so no danger in reading this pointer */
1051         table = t->private;
1052         /* make sure the table can only be rmmod'ed if it contains no rules */
1053         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1054                 ret = -ENOENT;
1055                 goto free_unlock;
1056         } else if (table->nentries && !newinfo->nentries)
1057                 module_put(t->me);
1058         /* we need an atomic snapshot of the counters */
1059         write_lock_bh(&t->lock);
1060         if (repl->num_counters)
1061                 get_counters(t->private->counters, counterstmp,
1062                    t->private->nentries);
1063
1064         t->private = newinfo;
1065         write_unlock_bh(&t->lock);
1066         mutex_unlock(&ebt_mutex);
1067         /* so, a user can change the chains while having messed up her counter
1068          * allocation. Only reason why this is done is because this way the lock
1069          * is held only once, while this doesn't bring the kernel into a
1070          * dangerous state.
1071          */
1072         if (repl->num_counters &&
1073            copy_to_user(repl->counters, counterstmp,
1074            repl->num_counters * sizeof(struct ebt_counter))) {
1075                 /* Silent error, can't fail, new table is already in place */
1076                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1077         }
1078
1079         /* decrease module count and free resources */
1080         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1081                           ebt_cleanup_entry, net, NULL);
1082
1083         vfree(table->entries);
1084         ebt_free_table_info(table);
1085         vfree(table);
1086         vfree(counterstmp);
1087
1088 #ifdef CONFIG_AUDIT
1089         if (audit_enabled) {
1090                 audit_log(audit_context(), GFP_KERNEL,
1091                           AUDIT_NETFILTER_CFG,
1092                           "table=%s family=%u entries=%u",
1093                           repl->name, AF_BRIDGE, repl->nentries);
1094         }
1095 #endif
1096         return ret;
1097
1098 free_unlock:
1099         mutex_unlock(&ebt_mutex);
1100 free_iterate:
1101         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1102                           ebt_cleanup_entry, net, NULL);
1103 free_counterstmp:
1104         vfree(counterstmp);
1105         /* can be initialized in translate_table() */
1106         ebt_free_table_info(newinfo);
1107         return ret;
1108 }
1109
1110 /* replace the table */
1111 static int do_replace(struct net *net, const void __user *user,
1112                       unsigned int len)
1113 {
1114         int ret, countersize;
1115         struct ebt_table_info *newinfo;
1116         struct ebt_replace tmp;
1117
1118         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1119                 return -EFAULT;
1120
1121         if (len != sizeof(tmp) + tmp.entries_size) {
1122                 BUGPRINT("Wrong len argument\n");
1123                 return -EINVAL;
1124         }
1125
1126         if (tmp.entries_size == 0) {
1127                 BUGPRINT("Entries_size never zero\n");
1128                 return -EINVAL;
1129         }
1130         /* overflow check */
1131         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1132                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1133                 return -ENOMEM;
1134         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1135                 return -ENOMEM;
1136
1137         tmp.name[sizeof(tmp.name) - 1] = 0;
1138
1139         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1140         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1141         if (!newinfo)
1142                 return -ENOMEM;
1143
1144         if (countersize)
1145                 memset(newinfo->counters, 0, countersize);
1146
1147         newinfo->entries = vmalloc(tmp.entries_size);
1148         if (!newinfo->entries) {
1149                 ret = -ENOMEM;
1150                 goto free_newinfo;
1151         }
1152         if (copy_from_user(
1153            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1154                 BUGPRINT("Couldn't copy entries from userspace\n");
1155                 ret = -EFAULT;
1156                 goto free_entries;
1157         }
1158
1159         ret = do_replace_finish(net, &tmp, newinfo);
1160         if (ret == 0)
1161                 return ret;
1162 free_entries:
1163         vfree(newinfo->entries);
1164 free_newinfo:
1165         vfree(newinfo);
1166         return ret;
1167 }
1168
1169 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1170 {
1171         mutex_lock(&ebt_mutex);
1172         list_del(&table->list);
1173         mutex_unlock(&ebt_mutex);
1174         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1175                           ebt_cleanup_entry, net, NULL);
1176         if (table->private->nentries)
1177                 module_put(table->me);
1178         vfree(table->private->entries);
1179         ebt_free_table_info(table->private);
1180         vfree(table->private);
1181         kfree(table);
1182 }
1183
1184 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1185                        const struct nf_hook_ops *ops, struct ebt_table **res)
1186 {
1187         struct ebt_table_info *newinfo;
1188         struct ebt_table *t, *table;
1189         struct ebt_replace_kernel *repl;
1190         int ret, i, countersize;
1191         void *p;
1192
1193         if (input_table == NULL || (repl = input_table->table) == NULL ||
1194             repl->entries == NULL || repl->entries_size == 0 ||
1195             repl->counters != NULL || input_table->private != NULL) {
1196                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1197                 return -EINVAL;
1198         }
1199
1200         /* Don't add one table to multiple lists. */
1201         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1202         if (!table) {
1203                 ret = -ENOMEM;
1204                 goto out;
1205         }
1206
1207         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1208         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1209         ret = -ENOMEM;
1210         if (!newinfo)
1211                 goto free_table;
1212
1213         p = vmalloc(repl->entries_size);
1214         if (!p)
1215                 goto free_newinfo;
1216
1217         memcpy(p, repl->entries, repl->entries_size);
1218         newinfo->entries = p;
1219
1220         newinfo->entries_size = repl->entries_size;
1221         newinfo->nentries = repl->nentries;
1222
1223         if (countersize)
1224                 memset(newinfo->counters, 0, countersize);
1225
1226         /* fill in newinfo and parse the entries */
1227         newinfo->chainstack = NULL;
1228         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1229                 if ((repl->valid_hooks & (1 << i)) == 0)
1230                         newinfo->hook_entry[i] = NULL;
1231                 else
1232                         newinfo->hook_entry[i] = p +
1233                                 ((char *)repl->hook_entry[i] - repl->entries);
1234         }
1235         ret = translate_table(net, repl->name, newinfo);
1236         if (ret != 0) {
1237                 BUGPRINT("Translate_table failed\n");
1238                 goto free_chainstack;
1239         }
1240
1241         if (table->check && table->check(newinfo, table->valid_hooks)) {
1242                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1243                 ret = -EINVAL;
1244                 goto free_chainstack;
1245         }
1246
1247         table->private = newinfo;
1248         rwlock_init(&table->lock);
1249         mutex_lock(&ebt_mutex);
1250         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1251                 if (strcmp(t->name, table->name) == 0) {
1252                         ret = -EEXIST;
1253                         BUGPRINT("Table name already exists\n");
1254                         goto free_unlock;
1255                 }
1256         }
1257
1258         /* Hold a reference count if the chains aren't empty */
1259         if (newinfo->nentries && !try_module_get(table->me)) {
1260                 ret = -ENOENT;
1261                 goto free_unlock;
1262         }
1263         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1264         mutex_unlock(&ebt_mutex);
1265
1266         WRITE_ONCE(*res, table);
1267
1268         if (!ops)
1269                 return 0;
1270
1271         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1272         if (ret) {
1273                 __ebt_unregister_table(net, table);
1274                 *res = NULL;
1275         }
1276
1277         return ret;
1278 free_unlock:
1279         mutex_unlock(&ebt_mutex);
1280 free_chainstack:
1281         ebt_free_table_info(newinfo);
1282         vfree(newinfo->entries);
1283 free_newinfo:
1284         vfree(newinfo);
1285 free_table:
1286         kfree(table);
1287 out:
1288         return ret;
1289 }
1290
1291 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1292                           const struct nf_hook_ops *ops)
1293 {
1294         if (ops)
1295                 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1296         __ebt_unregister_table(net, table);
1297 }
1298
1299 /* userspace just supplied us with counters */
1300 static int do_update_counters(struct net *net, const char *name,
1301                                 struct ebt_counter __user *counters,
1302                                 unsigned int num_counters,
1303                                 const void __user *user, unsigned int len)
1304 {
1305         int i, ret;
1306         struct ebt_counter *tmp;
1307         struct ebt_table *t;
1308
1309         if (num_counters == 0)
1310                 return -EINVAL;
1311
1312         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1313         if (!tmp)
1314                 return -ENOMEM;
1315
1316         t = find_table_lock(net, name, &ret, &ebt_mutex);
1317         if (!t)
1318                 goto free_tmp;
1319
1320         if (num_counters != t->private->nentries) {
1321                 BUGPRINT("Wrong nr of counters\n");
1322                 ret = -EINVAL;
1323                 goto unlock_mutex;
1324         }
1325
1326         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1327                 ret = -EFAULT;
1328                 goto unlock_mutex;
1329         }
1330
1331         /* we want an atomic add of the counters */
1332         write_lock_bh(&t->lock);
1333
1334         /* we add to the counters of the first cpu */
1335         for (i = 0; i < num_counters; i++)
1336                 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt);
1337
1338         write_unlock_bh(&t->lock);
1339         ret = 0;
1340 unlock_mutex:
1341         mutex_unlock(&ebt_mutex);
1342 free_tmp:
1343         vfree(tmp);
1344         return ret;
1345 }
1346
1347 static int update_counters(struct net *net, const void __user *user,
1348                             unsigned int len)
1349 {
1350         struct ebt_replace hlp;
1351
1352         if (copy_from_user(&hlp, user, sizeof(hlp)))
1353                 return -EFAULT;
1354
1355         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1356                 return -EINVAL;
1357
1358         return do_update_counters(net, hlp.name, hlp.counters,
1359                                 hlp.num_counters, user, len);
1360 }
1361
1362 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1363                                   const char *data, int entrysize,
1364                                   int usersize, int datasize, u8 revision)
1365 {
1366         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1367
1368         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1369          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1370          */
1371         strlcpy(name, _name, sizeof(name));
1372         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1373             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1374             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1375             xt_data_to_user(um + entrysize, data, usersize, datasize,
1376                             XT_ALIGN(datasize)))
1377                 return -EFAULT;
1378
1379         return 0;
1380 }
1381
1382 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1383                                     const char *base, char __user *ubase)
1384 {
1385         return ebt_obj_to_user(ubase + ((char *)m - base),
1386                                m->u.match->name, m->data, sizeof(*m),
1387                                m->u.match->usersize, m->match_size,
1388                                m->u.match->revision);
1389 }
1390
1391 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1392                                       const char *base, char __user *ubase)
1393 {
1394         return ebt_obj_to_user(ubase + ((char *)w - base),
1395                                w->u.watcher->name, w->data, sizeof(*w),
1396                                w->u.watcher->usersize, w->watcher_size,
1397                                w->u.watcher->revision);
1398 }
1399
1400 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1401                                     char __user *ubase)
1402 {
1403         int ret;
1404         char __user *hlp;
1405         const struct ebt_entry_target *t;
1406
1407         if (e->bitmask == 0) {
1408                 /* special case !EBT_ENTRY_OR_ENTRIES */
1409                 if (copy_to_user(ubase + ((char *)e - base), e,
1410                                  sizeof(struct ebt_entries)))
1411                         return -EFAULT;
1412                 return 0;
1413         }
1414
1415         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1416                 return -EFAULT;
1417
1418         hlp = ubase + (((char *)e + e->target_offset) - base);
1419         t = ebt_get_target_c(e);
1420
1421         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1422         if (ret != 0)
1423                 return ret;
1424         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1425         if (ret != 0)
1426                 return ret;
1427         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1428                               t->u.target->usersize, t->target_size,
1429                               t->u.target->revision);
1430         if (ret != 0)
1431                 return ret;
1432
1433         return 0;
1434 }
1435
1436 static int copy_counters_to_user(struct ebt_table *t,
1437                                  const struct ebt_counter *oldcounters,
1438                                  void __user *user, unsigned int num_counters,
1439                                  unsigned int nentries)
1440 {
1441         struct ebt_counter *counterstmp;
1442         int ret = 0;
1443
1444         /* userspace might not need the counters */
1445         if (num_counters == 0)
1446                 return 0;
1447
1448         if (num_counters != nentries) {
1449                 BUGPRINT("Num_counters wrong\n");
1450                 return -EINVAL;
1451         }
1452
1453         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1454         if (!counterstmp)
1455                 return -ENOMEM;
1456
1457         write_lock_bh(&t->lock);
1458         get_counters(oldcounters, counterstmp, nentries);
1459         write_unlock_bh(&t->lock);
1460
1461         if (copy_to_user(user, counterstmp,
1462            nentries * sizeof(struct ebt_counter)))
1463                 ret = -EFAULT;
1464         vfree(counterstmp);
1465         return ret;
1466 }
1467
1468 /* called with ebt_mutex locked */
1469 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1470                                    const int *len, int cmd)
1471 {
1472         struct ebt_replace tmp;
1473         const struct ebt_counter *oldcounters;
1474         unsigned int entries_size, nentries;
1475         int ret;
1476         char *entries;
1477
1478         if (cmd == EBT_SO_GET_ENTRIES) {
1479                 entries_size = t->private->entries_size;
1480                 nentries = t->private->nentries;
1481                 entries = t->private->entries;
1482                 oldcounters = t->private->counters;
1483         } else {
1484                 entries_size = t->table->entries_size;
1485                 nentries = t->table->nentries;
1486                 entries = t->table->entries;
1487                 oldcounters = t->table->counters;
1488         }
1489
1490         if (copy_from_user(&tmp, user, sizeof(tmp)))
1491                 return -EFAULT;
1492
1493         if (*len != sizeof(struct ebt_replace) + entries_size +
1494            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1495                 return -EINVAL;
1496
1497         if (tmp.nentries != nentries) {
1498                 BUGPRINT("Nentries wrong\n");
1499                 return -EINVAL;
1500         }
1501
1502         if (tmp.entries_size != entries_size) {
1503                 BUGPRINT("Wrong size\n");
1504                 return -EINVAL;
1505         }
1506
1507         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1508                                         tmp.num_counters, nentries);
1509         if (ret)
1510                 return ret;
1511
1512         /* set the match/watcher/target names right */
1513         return EBT_ENTRY_ITERATE(entries, entries_size,
1514            ebt_entry_to_user, entries, tmp.entries);
1515 }
1516
1517 static int do_ebt_set_ctl(struct sock *sk,
1518         int cmd, void __user *user, unsigned int len)
1519 {
1520         int ret;
1521         struct net *net = sock_net(sk);
1522
1523         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1524                 return -EPERM;
1525
1526         switch (cmd) {
1527         case EBT_SO_SET_ENTRIES:
1528                 ret = do_replace(net, user, len);
1529                 break;
1530         case EBT_SO_SET_COUNTERS:
1531                 ret = update_counters(net, user, len);
1532                 break;
1533         default:
1534                 ret = -EINVAL;
1535         }
1536         return ret;
1537 }
1538
1539 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1540 {
1541         int ret;
1542         struct ebt_replace tmp;
1543         struct ebt_table *t;
1544         struct net *net = sock_net(sk);
1545
1546         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1547                 return -EPERM;
1548
1549         if (copy_from_user(&tmp, user, sizeof(tmp)))
1550                 return -EFAULT;
1551
1552         tmp.name[sizeof(tmp.name) - 1] = '\0';
1553
1554         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1555         if (!t)
1556                 return ret;
1557
1558         switch (cmd) {
1559         case EBT_SO_GET_INFO:
1560         case EBT_SO_GET_INIT_INFO:
1561                 if (*len != sizeof(struct ebt_replace)) {
1562                         ret = -EINVAL;
1563                         mutex_unlock(&ebt_mutex);
1564                         break;
1565                 }
1566                 if (cmd == EBT_SO_GET_INFO) {
1567                         tmp.nentries = t->private->nentries;
1568                         tmp.entries_size = t->private->entries_size;
1569                         tmp.valid_hooks = t->valid_hooks;
1570                 } else {
1571                         tmp.nentries = t->table->nentries;
1572                         tmp.entries_size = t->table->entries_size;
1573                         tmp.valid_hooks = t->table->valid_hooks;
1574                 }
1575                 mutex_unlock(&ebt_mutex);
1576                 if (copy_to_user(user, &tmp, *len) != 0) {
1577                         BUGPRINT("c2u Didn't work\n");
1578                         ret = -EFAULT;
1579                         break;
1580                 }
1581                 ret = 0;
1582                 break;
1583
1584         case EBT_SO_GET_ENTRIES:
1585         case EBT_SO_GET_INIT_ENTRIES:
1586                 ret = copy_everything_to_user(t, user, len, cmd);
1587                 mutex_unlock(&ebt_mutex);
1588                 break;
1589
1590         default:
1591                 mutex_unlock(&ebt_mutex);
1592                 ret = -EINVAL;
1593         }
1594
1595         return ret;
1596 }
1597
1598 #ifdef CONFIG_COMPAT
1599 /* 32 bit-userspace compatibility definitions. */
1600 struct compat_ebt_replace {
1601         char name[EBT_TABLE_MAXNAMELEN];
1602         compat_uint_t valid_hooks;
1603         compat_uint_t nentries;
1604         compat_uint_t entries_size;
1605         /* start of the chains */
1606         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1607         /* nr of counters userspace expects back */
1608         compat_uint_t num_counters;
1609         /* where the kernel will put the old counters. */
1610         compat_uptr_t counters;
1611         compat_uptr_t entries;
1612 };
1613
1614 /* struct ebt_entry_match, _target and _watcher have same layout */
1615 struct compat_ebt_entry_mwt {
1616         union {
1617                 struct {
1618                         char name[EBT_EXTENSION_MAXNAMELEN];
1619                         u8 revision;
1620                 };
1621                 compat_uptr_t ptr;
1622         } u;
1623         compat_uint_t match_size;
1624         compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace))));
1625 };
1626
1627 /* account for possible padding between match_size and ->data */
1628 static int ebt_compat_entry_padsize(void)
1629 {
1630         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1631                         sizeof(struct compat_ebt_entry_mwt));
1632         return (int) sizeof(struct ebt_entry_match) -
1633                         sizeof(struct compat_ebt_entry_mwt);
1634 }
1635
1636 static int ebt_compat_match_offset(const struct xt_match *match,
1637                                    unsigned int userlen)
1638 {
1639         /* ebt_among needs special handling. The kernel .matchsize is
1640          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1641          * value is expected.
1642          * Example: userspace sends 4500, ebt_among.c wants 4504.
1643          */
1644         if (unlikely(match->matchsize == -1))
1645                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1646         return xt_compat_match_offset(match);
1647 }
1648
1649 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1650                                 unsigned int *size)
1651 {
1652         const struct xt_match *match = m->u.match;
1653         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1654         int off = ebt_compat_match_offset(match, m->match_size);
1655         compat_uint_t msize = m->match_size - off;
1656
1657         if (WARN_ON(off >= m->match_size))
1658                 return -EINVAL;
1659
1660         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1661             put_user(match->revision, &cm->u.revision) ||
1662             put_user(msize, &cm->match_size))
1663                 return -EFAULT;
1664
1665         if (match->compat_to_user) {
1666                 if (match->compat_to_user(cm->data, m->data))
1667                         return -EFAULT;
1668         } else {
1669                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1670                                     COMPAT_XT_ALIGN(msize)))
1671                         return -EFAULT;
1672         }
1673
1674         *size -= ebt_compat_entry_padsize() + off;
1675         *dstptr = cm->data;
1676         *dstptr += msize;
1677         return 0;
1678 }
1679
1680 static int compat_target_to_user(struct ebt_entry_target *t,
1681                                  void __user **dstptr,
1682                                  unsigned int *size)
1683 {
1684         const struct xt_target *target = t->u.target;
1685         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1686         int off = xt_compat_target_offset(target);
1687         compat_uint_t tsize = t->target_size - off;
1688
1689         if (WARN_ON(off >= t->target_size))
1690                 return -EINVAL;
1691
1692         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1693             put_user(target->revision, &cm->u.revision) ||
1694             put_user(tsize, &cm->match_size))
1695                 return -EFAULT;
1696
1697         if (target->compat_to_user) {
1698                 if (target->compat_to_user(cm->data, t->data))
1699                         return -EFAULT;
1700         } else {
1701                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1702                                     COMPAT_XT_ALIGN(tsize)))
1703                         return -EFAULT;
1704         }
1705
1706         *size -= ebt_compat_entry_padsize() + off;
1707         *dstptr = cm->data;
1708         *dstptr += tsize;
1709         return 0;
1710 }
1711
1712 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1713                                   void __user **dstptr,
1714                                   unsigned int *size)
1715 {
1716         return compat_target_to_user((struct ebt_entry_target *)w,
1717                                                         dstptr, size);
1718 }
1719
1720 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1721                                 unsigned int *size)
1722 {
1723         struct ebt_entry_target *t;
1724         struct ebt_entry __user *ce;
1725         u32 watchers_offset, target_offset, next_offset;
1726         compat_uint_t origsize;
1727         int ret;
1728
1729         if (e->bitmask == 0) {
1730                 if (*size < sizeof(struct ebt_entries))
1731                         return -EINVAL;
1732                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1733                         return -EFAULT;
1734
1735                 *dstptr += sizeof(struct ebt_entries);
1736                 *size -= sizeof(struct ebt_entries);
1737                 return 0;
1738         }
1739
1740         if (*size < sizeof(*ce))
1741                 return -EINVAL;
1742
1743         ce = *dstptr;
1744         if (copy_to_user(ce, e, sizeof(*ce)))
1745                 return -EFAULT;
1746
1747         origsize = *size;
1748         *dstptr += sizeof(*ce);
1749
1750         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1751         if (ret)
1752                 return ret;
1753         watchers_offset = e->watchers_offset - (origsize - *size);
1754
1755         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1756         if (ret)
1757                 return ret;
1758         target_offset = e->target_offset - (origsize - *size);
1759
1760         t = ebt_get_target(e);
1761
1762         ret = compat_target_to_user(t, dstptr, size);
1763         if (ret)
1764                 return ret;
1765         next_offset = e->next_offset - (origsize - *size);
1766
1767         if (put_user(watchers_offset, &ce->watchers_offset) ||
1768             put_user(target_offset, &ce->target_offset) ||
1769             put_user(next_offset, &ce->next_offset))
1770                 return -EFAULT;
1771
1772         *size -= sizeof(*ce);
1773         return 0;
1774 }
1775
1776 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1777 {
1778         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1779         *off += ebt_compat_entry_padsize();
1780         return 0;
1781 }
1782
1783 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1784 {
1785         *off += xt_compat_target_offset(w->u.watcher);
1786         *off += ebt_compat_entry_padsize();
1787         return 0;
1788 }
1789
1790 static int compat_calc_entry(const struct ebt_entry *e,
1791                              const struct ebt_table_info *info,
1792                              const void *base,
1793                              struct compat_ebt_replace *newinfo)
1794 {
1795         const struct ebt_entry_target *t;
1796         unsigned int entry_offset;
1797         int off, ret, i;
1798
1799         if (e->bitmask == 0)
1800                 return 0;
1801
1802         off = 0;
1803         entry_offset = (void *)e - base;
1804
1805         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1806         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1807
1808         t = ebt_get_target_c(e);
1809
1810         off += xt_compat_target_offset(t->u.target);
1811         off += ebt_compat_entry_padsize();
1812
1813         newinfo->entries_size -= off;
1814
1815         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1816         if (ret)
1817                 return ret;
1818
1819         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1820                 const void *hookptr = info->hook_entry[i];
1821                 if (info->hook_entry[i] &&
1822                     (e < (struct ebt_entry *)(base - hookptr))) {
1823                         newinfo->hook_entry[i] -= off;
1824                         pr_debug("0x%08X -> 0x%08X\n",
1825                                         newinfo->hook_entry[i] + off,
1826                                         newinfo->hook_entry[i]);
1827                 }
1828         }
1829
1830         return 0;
1831 }
1832
1833
1834 static int compat_table_info(const struct ebt_table_info *info,
1835                              struct compat_ebt_replace *newinfo)
1836 {
1837         unsigned int size = info->entries_size;
1838         const void *entries = info->entries;
1839
1840         newinfo->entries_size = size;
1841         if (info->nentries) {
1842                 int ret = xt_compat_init_offsets(NFPROTO_BRIDGE,
1843                                                  info->nentries);
1844                 if (ret)
1845                         return ret;
1846         }
1847
1848         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1849                                                         entries, newinfo);
1850 }
1851
1852 static int compat_copy_everything_to_user(struct ebt_table *t,
1853                                           void __user *user, int *len, int cmd)
1854 {
1855         struct compat_ebt_replace repl, tmp;
1856         struct ebt_counter *oldcounters;
1857         struct ebt_table_info tinfo;
1858         int ret;
1859         void __user *pos;
1860
1861         memset(&tinfo, 0, sizeof(tinfo));
1862
1863         if (cmd == EBT_SO_GET_ENTRIES) {
1864                 tinfo.entries_size = t->private->entries_size;
1865                 tinfo.nentries = t->private->nentries;
1866                 tinfo.entries = t->private->entries;
1867                 oldcounters = t->private->counters;
1868         } else {
1869                 tinfo.entries_size = t->table->entries_size;
1870                 tinfo.nentries = t->table->nentries;
1871                 tinfo.entries = t->table->entries;
1872                 oldcounters = t->table->counters;
1873         }
1874
1875         if (copy_from_user(&tmp, user, sizeof(tmp)))
1876                 return -EFAULT;
1877
1878         if (tmp.nentries != tinfo.nentries ||
1879            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1880                 return -EINVAL;
1881
1882         memcpy(&repl, &tmp, sizeof(repl));
1883         if (cmd == EBT_SO_GET_ENTRIES)
1884                 ret = compat_table_info(t->private, &repl);
1885         else
1886                 ret = compat_table_info(&tinfo, &repl);
1887         if (ret)
1888                 return ret;
1889
1890         if (*len != sizeof(tmp) + repl.entries_size +
1891            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1892                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1893                                 *len, tinfo.entries_size, repl.entries_size);
1894                 return -EINVAL;
1895         }
1896
1897         /* userspace might not need the counters */
1898         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1899                                         tmp.num_counters, tinfo.nentries);
1900         if (ret)
1901                 return ret;
1902
1903         pos = compat_ptr(tmp.entries);
1904         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1905                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1906 }
1907
1908 struct ebt_entries_buf_state {
1909         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1910         u32 buf_kern_len;       /* total size of kernel buffer */
1911         u32 buf_kern_offset;    /* amount of data copied so far */
1912         u32 buf_user_offset;    /* read position in userspace buffer */
1913 };
1914
1915 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1916 {
1917         state->buf_kern_offset += sz;
1918         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1919 }
1920
1921 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1922                        void *data, unsigned int sz)
1923 {
1924         if (state->buf_kern_start == NULL)
1925                 goto count_only;
1926
1927         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1928                 return -EINVAL;
1929
1930         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1931
1932  count_only:
1933         state->buf_user_offset += sz;
1934         return ebt_buf_count(state, sz);
1935 }
1936
1937 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1938 {
1939         char *b = state->buf_kern_start;
1940
1941         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1942                 return -EINVAL;
1943
1944         if (b != NULL && sz > 0)
1945                 memset(b + state->buf_kern_offset, 0, sz);
1946         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1947         return ebt_buf_count(state, sz);
1948 }
1949
1950 enum compat_mwt {
1951         EBT_COMPAT_MATCH,
1952         EBT_COMPAT_WATCHER,
1953         EBT_COMPAT_TARGET,
1954 };
1955
1956 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1957                                 enum compat_mwt compat_mwt,
1958                                 struct ebt_entries_buf_state *state,
1959                                 const unsigned char *base)
1960 {
1961         char name[EBT_EXTENSION_MAXNAMELEN];
1962         struct xt_match *match;
1963         struct xt_target *wt;
1964         void *dst = NULL;
1965         int off, pad = 0;
1966         unsigned int size_kern, match_size = mwt->match_size;
1967
1968         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1969                 return -EINVAL;
1970
1971         if (state->buf_kern_start)
1972                 dst = state->buf_kern_start + state->buf_kern_offset;
1973
1974         switch (compat_mwt) {
1975         case EBT_COMPAT_MATCH:
1976                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1977                                               mwt->u.revision);
1978                 if (IS_ERR(match))
1979                         return PTR_ERR(match);
1980
1981                 off = ebt_compat_match_offset(match, match_size);
1982                 if (dst) {
1983                         if (match->compat_from_user)
1984                                 match->compat_from_user(dst, mwt->data);
1985                         else
1986                                 memcpy(dst, mwt->data, match_size);
1987                 }
1988
1989                 size_kern = match->matchsize;
1990                 if (unlikely(size_kern == -1))
1991                         size_kern = match_size;
1992                 module_put(match->me);
1993                 break;
1994         case EBT_COMPAT_WATCHER: /* fallthrough */
1995         case EBT_COMPAT_TARGET:
1996                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1997                                             mwt->u.revision);
1998                 if (IS_ERR(wt))
1999                         return PTR_ERR(wt);
2000                 off = xt_compat_target_offset(wt);
2001
2002                 if (dst) {
2003                         if (wt->compat_from_user)
2004                                 wt->compat_from_user(dst, mwt->data);
2005                         else
2006                                 memcpy(dst, mwt->data, match_size);
2007                 }
2008
2009                 size_kern = wt->targetsize;
2010                 module_put(wt->me);
2011                 break;
2012
2013         default:
2014                 return -EINVAL;
2015         }
2016
2017         state->buf_kern_offset += match_size + off;
2018         state->buf_user_offset += match_size;
2019         pad = XT_ALIGN(size_kern) - size_kern;
2020
2021         if (pad > 0 && dst) {
2022                 if (WARN_ON(state->buf_kern_len <= pad))
2023                         return -EINVAL;
2024                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2025                         return -EINVAL;
2026                 memset(dst + size_kern, 0, pad);
2027         }
2028         return off + match_size;
2029 }
2030
2031 /* return size of all matches, watchers or target, including necessary
2032  * alignment and padding.
2033  */
2034 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2035                         unsigned int size_left, enum compat_mwt type,
2036                         struct ebt_entries_buf_state *state, const void *base)
2037 {
2038         int growth = 0;
2039         char *buf;
2040
2041         if (size_left == 0)
2042                 return 0;
2043
2044         buf = (char *) match32;
2045
2046         while (size_left >= sizeof(*match32)) {
2047                 struct ebt_entry_match *match_kern;
2048                 int ret;
2049
2050                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2051                 if (match_kern) {
2052                         char *tmp;
2053                         tmp = state->buf_kern_start + state->buf_kern_offset;
2054                         match_kern = (struct ebt_entry_match *) tmp;
2055                 }
2056                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2057                 if (ret < 0)
2058                         return ret;
2059                 size_left -= sizeof(*match32);
2060
2061                 /* add padding before match->data (if any) */
2062                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2063                 if (ret < 0)
2064                         return ret;
2065
2066                 if (match32->match_size > size_left)
2067                         return -EINVAL;
2068
2069                 size_left -= match32->match_size;
2070
2071                 ret = compat_mtw_from_user(match32, type, state, base);
2072                 if (ret < 0)
2073                         return ret;
2074
2075                 if (WARN_ON(ret < match32->match_size))
2076                         return -EINVAL;
2077                 growth += ret - match32->match_size;
2078                 growth += ebt_compat_entry_padsize();
2079
2080                 buf += sizeof(*match32);
2081                 buf += match32->match_size;
2082
2083                 if (match_kern)
2084                         match_kern->match_size = ret;
2085
2086                 if (WARN_ON(type == EBT_COMPAT_TARGET && size_left))
2087                         return -EINVAL;
2088
2089                 match32 = (struct compat_ebt_entry_mwt *) buf;
2090         }
2091
2092         return growth;
2093 }
2094
2095 /* called for all ebt_entry structures. */
2096 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2097                           unsigned int *total,
2098                           struct ebt_entries_buf_state *state)
2099 {
2100         unsigned int i, j, startoff, new_offset = 0;
2101         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2102         unsigned int offsets[4];
2103         unsigned int *offsets_update = NULL;
2104         int ret;
2105         char *buf_start;
2106
2107         if (*total < sizeof(struct ebt_entries))
2108                 return -EINVAL;
2109
2110         if (!entry->bitmask) {
2111                 *total -= sizeof(struct ebt_entries);
2112                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2113         }
2114         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2115                 return -EINVAL;
2116
2117         startoff = state->buf_user_offset;
2118         /* pull in most part of ebt_entry, it does not need to be changed. */
2119         ret = ebt_buf_add(state, entry,
2120                         offsetof(struct ebt_entry, watchers_offset));
2121         if (ret < 0)
2122                 return ret;
2123
2124         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2125         memcpy(&offsets[1], &entry->watchers_offset,
2126                         sizeof(offsets) - sizeof(offsets[0]));
2127
2128         if (state->buf_kern_start) {
2129                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2130                 offsets_update = (unsigned int *) buf_start;
2131         }
2132         ret = ebt_buf_add(state, &offsets[1],
2133                         sizeof(offsets) - sizeof(offsets[0]));
2134         if (ret < 0)
2135                 return ret;
2136         buf_start = (char *) entry;
2137         /* 0: matches offset, always follows ebt_entry.
2138          * 1: watchers offset, from ebt_entry structure
2139          * 2: target offset, from ebt_entry structure
2140          * 3: next ebt_entry offset, from ebt_entry structure
2141          *
2142          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2143          */
2144         for (i = 0; i < 4 ; ++i) {
2145                 if (offsets[i] > *total)
2146                         return -EINVAL;
2147
2148                 if (i < 3 && offsets[i] == *total)
2149                         return -EINVAL;
2150
2151                 if (i == 0)
2152                         continue;
2153                 if (offsets[i-1] > offsets[i])
2154                         return -EINVAL;
2155         }
2156
2157         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2158                 struct compat_ebt_entry_mwt *match32;
2159                 unsigned int size;
2160                 char *buf = buf_start + offsets[i];
2161
2162                 if (offsets[i] > offsets[j])
2163                         return -EINVAL;
2164
2165                 match32 = (struct compat_ebt_entry_mwt *) buf;
2166                 size = offsets[j] - offsets[i];
2167                 ret = ebt_size_mwt(match32, size, i, state, base);
2168                 if (ret < 0)
2169                         return ret;
2170                 new_offset += ret;
2171                 if (offsets_update && new_offset) {
2172                         pr_debug("change offset %d to %d\n",
2173                                 offsets_update[i], offsets[j] + new_offset);
2174                         offsets_update[i] = offsets[j] + new_offset;
2175                 }
2176         }
2177
2178         if (state->buf_kern_start == NULL) {
2179                 unsigned int offset = buf_start - (char *) base;
2180
2181                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2182                 if (ret < 0)
2183                         return ret;
2184         }
2185
2186         startoff = state->buf_user_offset - startoff;
2187
2188         if (WARN_ON(*total < startoff))
2189                 return -EINVAL;
2190         *total -= startoff;
2191         return 0;
2192 }
2193
2194 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2195  * It might need more memory when copied to a 64 bit kernel in case
2196  * userspace is 32-bit. So, first task: find out how much memory is needed.
2197  *
2198  * Called before validation is performed.
2199  */
2200 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2201                                 struct ebt_entries_buf_state *state)
2202 {
2203         unsigned int size_remaining = size_user;
2204         int ret;
2205
2206         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2207                                         &size_remaining, state);
2208         if (ret < 0)
2209                 return ret;
2210
2211         WARN_ON(size_remaining);
2212         return state->buf_kern_offset;
2213 }
2214
2215
2216 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2217                                             void __user *user, unsigned int len)
2218 {
2219         struct compat_ebt_replace tmp;
2220         int i;
2221
2222         if (len < sizeof(tmp))
2223                 return -EINVAL;
2224
2225         if (copy_from_user(&tmp, user, sizeof(tmp)))
2226                 return -EFAULT;
2227
2228         if (len != sizeof(tmp) + tmp.entries_size)
2229                 return -EINVAL;
2230
2231         if (tmp.entries_size == 0)
2232                 return -EINVAL;
2233
2234         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2235                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2236                 return -ENOMEM;
2237         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2238                 return -ENOMEM;
2239
2240         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2241
2242         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2243         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2244                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2245
2246         repl->num_counters = tmp.num_counters;
2247         repl->counters = compat_ptr(tmp.counters);
2248         repl->entries = compat_ptr(tmp.entries);
2249         return 0;
2250 }
2251
2252 static int compat_do_replace(struct net *net, void __user *user,
2253                              unsigned int len)
2254 {
2255         int ret, i, countersize, size64;
2256         struct ebt_table_info *newinfo;
2257         struct ebt_replace tmp;
2258         struct ebt_entries_buf_state state;
2259         void *entries_tmp;
2260
2261         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2262         if (ret) {
2263                 /* try real handler in case userland supplied needed padding */
2264                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2265                         ret = 0;
2266                 return ret;
2267         }
2268
2269         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2270         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2271         if (!newinfo)
2272                 return -ENOMEM;
2273
2274         if (countersize)
2275                 memset(newinfo->counters, 0, countersize);
2276
2277         memset(&state, 0, sizeof(state));
2278
2279         newinfo->entries = vmalloc(tmp.entries_size);
2280         if (!newinfo->entries) {
2281                 ret = -ENOMEM;
2282                 goto free_newinfo;
2283         }
2284         if (copy_from_user(
2285            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2286                 ret = -EFAULT;
2287                 goto free_entries;
2288         }
2289
2290         entries_tmp = newinfo->entries;
2291
2292         xt_compat_lock(NFPROTO_BRIDGE);
2293
2294         ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2295         if (ret < 0)
2296                 goto out_unlock;
2297         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2298         if (ret < 0)
2299                 goto out_unlock;
2300
2301         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2302                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2303                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2304
2305         size64 = ret;
2306         newinfo->entries = vmalloc(size64);
2307         if (!newinfo->entries) {
2308                 vfree(entries_tmp);
2309                 ret = -ENOMEM;
2310                 goto out_unlock;
2311         }
2312
2313         memset(&state, 0, sizeof(state));
2314         state.buf_kern_start = newinfo->entries;
2315         state.buf_kern_len = size64;
2316
2317         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2318         if (WARN_ON(ret < 0))
2319                 goto out_unlock;
2320
2321         vfree(entries_tmp);
2322         tmp.entries_size = size64;
2323
2324         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2325                 char __user *usrptr;
2326                 if (tmp.hook_entry[i]) {
2327                         unsigned int delta;
2328                         usrptr = (char __user *) tmp.hook_entry[i];
2329                         delta = usrptr - tmp.entries;
2330                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2331                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2332                 }
2333         }
2334
2335         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2336         xt_compat_unlock(NFPROTO_BRIDGE);
2337
2338         ret = do_replace_finish(net, &tmp, newinfo);
2339         if (ret == 0)
2340                 return ret;
2341 free_entries:
2342         vfree(newinfo->entries);
2343 free_newinfo:
2344         vfree(newinfo);
2345         return ret;
2346 out_unlock:
2347         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2348         xt_compat_unlock(NFPROTO_BRIDGE);
2349         goto free_entries;
2350 }
2351
2352 static int compat_update_counters(struct net *net, void __user *user,
2353                                   unsigned int len)
2354 {
2355         struct compat_ebt_replace hlp;
2356
2357         if (copy_from_user(&hlp, user, sizeof(hlp)))
2358                 return -EFAULT;
2359
2360         /* try real handler in case userland supplied needed padding */
2361         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2362                 return update_counters(net, user, len);
2363
2364         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2365                                         hlp.num_counters, user, len);
2366 }
2367
2368 static int compat_do_ebt_set_ctl(struct sock *sk,
2369                 int cmd, void __user *user, unsigned int len)
2370 {
2371         int ret;
2372         struct net *net = sock_net(sk);
2373
2374         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2375                 return -EPERM;
2376
2377         switch (cmd) {
2378         case EBT_SO_SET_ENTRIES:
2379                 ret = compat_do_replace(net, user, len);
2380                 break;
2381         case EBT_SO_SET_COUNTERS:
2382                 ret = compat_update_counters(net, user, len);
2383                 break;
2384         default:
2385                 ret = -EINVAL;
2386         }
2387         return ret;
2388 }
2389
2390 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2391                 void __user *user, int *len)
2392 {
2393         int ret;
2394         struct compat_ebt_replace tmp;
2395         struct ebt_table *t;
2396         struct net *net = sock_net(sk);
2397
2398         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2399                 return -EPERM;
2400
2401         /* try real handler in case userland supplied needed padding */
2402         if ((cmd == EBT_SO_GET_INFO ||
2403              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2404                         return do_ebt_get_ctl(sk, cmd, user, len);
2405
2406         if (copy_from_user(&tmp, user, sizeof(tmp)))
2407                 return -EFAULT;
2408
2409         tmp.name[sizeof(tmp.name) - 1] = '\0';
2410
2411         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2412         if (!t)
2413                 return ret;
2414
2415         xt_compat_lock(NFPROTO_BRIDGE);
2416         switch (cmd) {
2417         case EBT_SO_GET_INFO:
2418                 tmp.nentries = t->private->nentries;
2419                 ret = compat_table_info(t->private, &tmp);
2420                 if (ret)
2421                         goto out;
2422                 tmp.valid_hooks = t->valid_hooks;
2423
2424                 if (copy_to_user(user, &tmp, *len) != 0) {
2425                         ret = -EFAULT;
2426                         break;
2427                 }
2428                 ret = 0;
2429                 break;
2430         case EBT_SO_GET_INIT_INFO:
2431                 tmp.nentries = t->table->nentries;
2432                 tmp.entries_size = t->table->entries_size;
2433                 tmp.valid_hooks = t->table->valid_hooks;
2434
2435                 if (copy_to_user(user, &tmp, *len) != 0) {
2436                         ret = -EFAULT;
2437                         break;
2438                 }
2439                 ret = 0;
2440                 break;
2441         case EBT_SO_GET_ENTRIES:
2442         case EBT_SO_GET_INIT_ENTRIES:
2443                 /* try real handler first in case of userland-side padding.
2444                  * in case we are dealing with an 'ordinary' 32 bit binary
2445                  * without 64bit compatibility padding, this will fail right
2446                  * after copy_from_user when the *len argument is validated.
2447                  *
2448                  * the compat_ variant needs to do one pass over the kernel
2449                  * data set to adjust for size differences before it the check.
2450                  */
2451                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2452                         ret = 0;
2453                 else
2454                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2455                 break;
2456         default:
2457                 ret = -EINVAL;
2458         }
2459  out:
2460         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2461         xt_compat_unlock(NFPROTO_BRIDGE);
2462         mutex_unlock(&ebt_mutex);
2463         return ret;
2464 }
2465 #endif
2466
2467 static struct nf_sockopt_ops ebt_sockopts = {
2468         .pf             = PF_INET,
2469         .set_optmin     = EBT_BASE_CTL,
2470         .set_optmax     = EBT_SO_SET_MAX + 1,
2471         .set            = do_ebt_set_ctl,
2472 #ifdef CONFIG_COMPAT
2473         .compat_set     = compat_do_ebt_set_ctl,
2474 #endif
2475         .get_optmin     = EBT_BASE_CTL,
2476         .get_optmax     = EBT_SO_GET_MAX + 1,
2477         .get            = do_ebt_get_ctl,
2478 #ifdef CONFIG_COMPAT
2479         .compat_get     = compat_do_ebt_get_ctl,
2480 #endif
2481         .owner          = THIS_MODULE,
2482 };
2483
2484 static int __init ebtables_init(void)
2485 {
2486         int ret;
2487
2488         ret = xt_register_target(&ebt_standard_target);
2489         if (ret < 0)
2490                 return ret;
2491         ret = nf_register_sockopt(&ebt_sockopts);
2492         if (ret < 0) {
2493                 xt_unregister_target(&ebt_standard_target);
2494                 return ret;
2495         }
2496
2497         return 0;
2498 }
2499
2500 static void __exit ebtables_fini(void)
2501 {
2502         nf_unregister_sockopt(&ebt_sockopts);
2503         xt_unregister_target(&ebt_standard_target);
2504 }
2505
2506 EXPORT_SYMBOL(ebt_register_table);
2507 EXPORT_SYMBOL(ebt_unregister_table);
2508 EXPORT_SYMBOL(ebt_do_table);
2509 module_init(ebtables_init);
2510 module_exit(ebtables_fini);
2511 MODULE_LICENSE("GPL");