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