1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * ebtables 4 * 5 * Author: 6 * Bart De Schuymer <bdschuym@pandora.be> 7 * 8 * ebtables.c,v 2.0, July, 2002 9 * 10 * This code is strongly inspired by the iptables code which is 11 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 12 */ 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 #include <linux/kmod.h> 15 #include <linux/module.h> 16 #include <linux/vmalloc.h> 17 #include <linux/netfilter/x_tables.h> 18 #include <linux/netfilter_bridge/ebtables.h> 19 #include <linux/spinlock.h> 20 #include <linux/mutex.h> 21 #include <linux/slab.h> 22 #include <linux/uaccess.h> 23 #include <linux/smp.h> 24 #include <linux/cpumask.h> 25 #include <linux/audit.h> 26 #include <net/sock.h> 27 #include <net/netns/generic.h> 28 /* needed for logical [in,out]-dev filtering */ 29 #include "../br_private.h" 30 31 /* Each cpu has its own set of counters, so there is no need for write_lock in 32 * the softirq 33 * For reading or updating the counters, the user context needs to 34 * get a write_lock 35 */ 36 37 /* The size of each set of counters is altered to get cache alignment */ 38 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) 39 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter))) 40 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \ 41 COUNTER_OFFSET(n) * cpu)) 42 43 struct ebt_pernet { 44 struct list_head tables; 45 }; 46 47 struct ebt_template { 48 struct list_head list; 49 char name[EBT_TABLE_MAXNAMELEN]; 50 struct module *owner; 51 /* called when table is needed in the given netns */ 52 int (*table_init)(struct net *net); 53 }; 54 55 static unsigned int ebt_pernet_id __read_mostly; 56 static LIST_HEAD(template_tables); 57 static DEFINE_MUTEX(ebt_mutex); 58 59 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 60 static void ebt_standard_compat_from_user(void *dst, const void *src) 61 { 62 int v = *(compat_int_t *)src; 63 64 if (v >= 0) 65 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v); 66 memcpy(dst, &v, sizeof(v)); 67 } 68 69 static int ebt_standard_compat_to_user(void __user *dst, const void *src) 70 { 71 compat_int_t cv = *(int *)src; 72 73 if (cv >= 0) 74 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv); 75 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 76 } 77 #endif 78 79 80 static struct xt_target ebt_standard_target = { 81 .name = "standard", 82 .revision = 0, 83 .family = NFPROTO_BRIDGE, 84 .targetsize = sizeof(int), 85 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 86 .compatsize = sizeof(compat_int_t), 87 .compat_from_user = ebt_standard_compat_from_user, 88 .compat_to_user = ebt_standard_compat_to_user, 89 #endif 90 }; 91 92 static inline int 93 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb, 94 struct xt_action_param *par) 95 { 96 par->target = w->u.watcher; 97 par->targinfo = w->data; 98 w->u.watcher->target(skb, par); 99 /* watchers don't give a verdict */ 100 return 0; 101 } 102 103 static inline int 104 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb, 105 struct xt_action_param *par) 106 { 107 par->match = m->u.match; 108 par->matchinfo = m->data; 109 return !m->u.match->match(skb, par); 110 } 111 112 static inline int 113 ebt_dev_check(const char *entry, const struct net_device *device) 114 { 115 int i = 0; 116 const char *devname; 117 118 if (*entry == '\0') 119 return 0; 120 if (!device) 121 return 1; 122 devname = device->name; 123 /* 1 is the wildcard token */ 124 while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i]) 125 i++; 126 return devname[i] != entry[i] && entry[i] != 1; 127 } 128 129 /* process standard matches */ 130 static inline int 131 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb, 132 const struct net_device *in, const struct net_device *out) 133 { 134 const struct ethhdr *h = eth_hdr(skb); 135 const struct net_bridge_port *p; 136 __be16 ethproto; 137 138 if (skb_vlan_tag_present(skb)) 139 ethproto = htons(ETH_P_8021Q); 140 else 141 ethproto = h->h_proto; 142 143 if (e->bitmask & EBT_802_3) { 144 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto))) 145 return 1; 146 } else if (!(e->bitmask & EBT_NOPROTO) && 147 NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto)) 148 return 1; 149 150 if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in))) 151 return 1; 152 if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out))) 153 return 1; 154 /* rcu_read_lock()ed by nf_hook_thresh */ 155 if (in && (p = br_port_get_rcu(in)) != NULL && 156 NF_INVF(e, EBT_ILOGICALIN, 157 ebt_dev_check(e->logical_in, p->br->dev))) 158 return 1; 159 if (out && (p = br_port_get_rcu(out)) != NULL && 160 NF_INVF(e, EBT_ILOGICALOUT, 161 ebt_dev_check(e->logical_out, p->br->dev))) 162 return 1; 163 164 if (e->bitmask & EBT_SOURCEMAC) { 165 if (NF_INVF(e, EBT_ISOURCE, 166 !ether_addr_equal_masked(h->h_source, e->sourcemac, 167 e->sourcemsk))) 168 return 1; 169 } 170 if (e->bitmask & EBT_DESTMAC) { 171 if (NF_INVF(e, EBT_IDEST, 172 !ether_addr_equal_masked(h->h_dest, e->destmac, 173 e->destmsk))) 174 return 1; 175 } 176 return 0; 177 } 178 179 static inline 180 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry) 181 { 182 return (void *)entry + entry->next_offset; 183 } 184 185 static inline const struct ebt_entry_target * 186 ebt_get_target_c(const struct ebt_entry *e) 187 { 188 return ebt_get_target((struct ebt_entry *)e); 189 } 190 191 /* Do some firewalling */ 192 unsigned int ebt_do_table(void *priv, struct sk_buff *skb, 193 const struct nf_hook_state *state) 194 { 195 struct ebt_table *table = priv; 196 unsigned int hook = state->hook; 197 int i, nentries; 198 struct ebt_entry *point; 199 struct ebt_counter *counter_base, *cb_base; 200 const struct ebt_entry_target *t; 201 int verdict, sp = 0; 202 struct ebt_chainstack *cs; 203 struct ebt_entries *chaininfo; 204 const char *base; 205 const struct ebt_table_info *private; 206 struct xt_action_param acpar; 207 208 acpar.state = state; 209 acpar.hotdrop = false; 210 211 read_lock_bh(&table->lock); 212 private = table->private; 213 cb_base = COUNTER_BASE(private->counters, private->nentries, 214 smp_processor_id()); 215 if (private->chainstack) 216 cs = private->chainstack[smp_processor_id()]; 217 else 218 cs = NULL; 219 chaininfo = private->hook_entry[hook]; 220 nentries = private->hook_entry[hook]->nentries; 221 point = (struct ebt_entry *)(private->hook_entry[hook]->data); 222 counter_base = cb_base + private->hook_entry[hook]->counter_offset; 223 /* base for chain jumps */ 224 base = private->entries; 225 i = 0; 226 while (i < nentries) { 227 if (ebt_basic_match(point, skb, state->in, state->out)) 228 goto letscontinue; 229 230 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0) 231 goto letscontinue; 232 if (acpar.hotdrop) { 233 read_unlock_bh(&table->lock); 234 return NF_DROP; 235 } 236 237 ADD_COUNTER(*(counter_base + i), skb->len, 1); 238 239 /* these should only watch: not modify, nor tell us 240 * what to do with the packet 241 */ 242 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar); 243 244 t = ebt_get_target_c(point); 245 /* standard target */ 246 if (!t->u.target->target) 247 verdict = ((struct ebt_standard_target *)t)->verdict; 248 else { 249 acpar.target = t->u.target; 250 acpar.targinfo = t->data; 251 verdict = t->u.target->target(skb, &acpar); 252 } 253 if (verdict == EBT_ACCEPT) { 254 read_unlock_bh(&table->lock); 255 return NF_ACCEPT; 256 } 257 if (verdict == EBT_DROP) { 258 read_unlock_bh(&table->lock); 259 return NF_DROP; 260 } 261 if (verdict == EBT_RETURN) { 262 letsreturn: 263 if (WARN(sp == 0, "RETURN on base chain")) { 264 /* act like this is EBT_CONTINUE */ 265 goto letscontinue; 266 } 267 268 sp--; 269 /* put all the local variables right */ 270 i = cs[sp].n; 271 chaininfo = cs[sp].chaininfo; 272 nentries = chaininfo->nentries; 273 point = cs[sp].e; 274 counter_base = cb_base + 275 chaininfo->counter_offset; 276 continue; 277 } 278 if (verdict == EBT_CONTINUE) 279 goto letscontinue; 280 281 if (WARN(verdict < 0, "bogus standard verdict\n")) { 282 read_unlock_bh(&table->lock); 283 return NF_DROP; 284 } 285 286 /* jump to a udc */ 287 cs[sp].n = i + 1; 288 cs[sp].chaininfo = chaininfo; 289 cs[sp].e = ebt_next_entry(point); 290 i = 0; 291 chaininfo = (struct ebt_entries *) (base + verdict); 292 293 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) { 294 read_unlock_bh(&table->lock); 295 return NF_DROP; 296 } 297 298 nentries = chaininfo->nentries; 299 point = (struct ebt_entry *)chaininfo->data; 300 counter_base = cb_base + chaininfo->counter_offset; 301 sp++; 302 continue; 303 letscontinue: 304 point = ebt_next_entry(point); 305 i++; 306 } 307 308 /* I actually like this :) */ 309 if (chaininfo->policy == EBT_RETURN) 310 goto letsreturn; 311 if (chaininfo->policy == EBT_ACCEPT) { 312 read_unlock_bh(&table->lock); 313 return NF_ACCEPT; 314 } 315 read_unlock_bh(&table->lock); 316 return NF_DROP; 317 } 318 319 /* If it succeeds, returns element and locks mutex */ 320 static inline void * 321 find_inlist_lock_noload(struct net *net, const char *name, int *error, 322 struct mutex *mutex) 323 { 324 struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); 325 struct ebt_template *tmpl; 326 struct ebt_table *table; 327 328 mutex_lock(mutex); 329 list_for_each_entry(table, &ebt_net->tables, list) { 330 if (strcmp(table->name, name) == 0) 331 return table; 332 } 333 334 list_for_each_entry(tmpl, &template_tables, list) { 335 if (strcmp(name, tmpl->name) == 0) { 336 struct module *owner = tmpl->owner; 337 338 if (!try_module_get(owner)) 339 goto out; 340 341 mutex_unlock(mutex); 342 343 *error = tmpl->table_init(net); 344 if (*error) { 345 module_put(owner); 346 return NULL; 347 } 348 349 mutex_lock(mutex); 350 module_put(owner); 351 break; 352 } 353 } 354 355 list_for_each_entry(table, &ebt_net->tables, list) { 356 if (strcmp(table->name, name) == 0) 357 return table; 358 } 359 360 out: 361 *error = -ENOENT; 362 mutex_unlock(mutex); 363 return NULL; 364 } 365 366 static void * 367 find_inlist_lock(struct net *net, const char *name, const char *prefix, 368 int *error, struct mutex *mutex) 369 { 370 return try_then_request_module( 371 find_inlist_lock_noload(net, name, error, mutex), 372 "%s%s", prefix, name); 373 } 374 375 static inline struct ebt_table * 376 find_table_lock(struct net *net, const char *name, int *error, 377 struct mutex *mutex) 378 { 379 return find_inlist_lock(net, name, "ebtable_", error, mutex); 380 } 381 382 static inline void ebt_free_table_info(struct ebt_table_info *info) 383 { 384 int i; 385 386 if (info->chainstack) { 387 for_each_possible_cpu(i) 388 vfree(info->chainstack[i]); 389 vfree(info->chainstack); 390 } 391 } 392 static inline int 393 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, 394 unsigned int *cnt) 395 { 396 const struct ebt_entry *e = par->entryinfo; 397 struct xt_match *match; 398 size_t left = ((char *)e + e->watchers_offset) - (char *)m; 399 int ret; 400 401 if (left < sizeof(struct ebt_entry_match) || 402 left - sizeof(struct ebt_entry_match) < m->match_size) 403 return -EINVAL; 404 405 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); 406 if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { 407 if (!IS_ERR(match)) 408 module_put(match->me); 409 request_module("ebt_%s", m->u.name); 410 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); 411 } 412 if (IS_ERR(match)) 413 return PTR_ERR(match); 414 m->u.match = match; 415 416 par->match = match; 417 par->matchinfo = m->data; 418 ret = xt_check_match(par, m->match_size, 419 ntohs(e->ethproto), e->invflags & EBT_IPROTO); 420 if (ret < 0) { 421 module_put(match->me); 422 return ret; 423 } 424 425 (*cnt)++; 426 return 0; 427 } 428 429 static inline int 430 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par, 431 unsigned int *cnt) 432 { 433 const struct ebt_entry *e = par->entryinfo; 434 struct xt_target *watcher; 435 size_t left = ((char *)e + e->target_offset) - (char *)w; 436 int ret; 437 438 if (left < sizeof(struct ebt_entry_watcher) || 439 left - sizeof(struct ebt_entry_watcher) < w->watcher_size) 440 return -EINVAL; 441 442 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); 443 if (IS_ERR(watcher)) 444 return PTR_ERR(watcher); 445 446 if (watcher->family != NFPROTO_BRIDGE) { 447 module_put(watcher->me); 448 return -ENOENT; 449 } 450 451 w->u.watcher = watcher; 452 453 par->target = watcher; 454 par->targinfo = w->data; 455 ret = xt_check_target(par, w->watcher_size, 456 ntohs(e->ethproto), e->invflags & EBT_IPROTO); 457 if (ret < 0) { 458 module_put(watcher->me); 459 return ret; 460 } 461 462 (*cnt)++; 463 return 0; 464 } 465 466 static int ebt_verify_pointers(const struct ebt_replace *repl, 467 struct ebt_table_info *newinfo) 468 { 469 unsigned int limit = repl->entries_size; 470 unsigned int valid_hooks = repl->valid_hooks; 471 unsigned int offset = 0; 472 int i; 473 474 for (i = 0; i < NF_BR_NUMHOOKS; i++) 475 newinfo->hook_entry[i] = NULL; 476 477 newinfo->entries_size = repl->entries_size; 478 newinfo->nentries = repl->nentries; 479 480 while (offset < limit) { 481 size_t left = limit - offset; 482 struct ebt_entry *e = (void *)newinfo->entries + offset; 483 484 if (left < sizeof(unsigned int)) 485 break; 486 487 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 488 if ((valid_hooks & (1 << i)) == 0) 489 continue; 490 if ((char __user *)repl->hook_entry[i] == 491 repl->entries + offset) 492 break; 493 } 494 495 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { 496 if (e->bitmask != 0) { 497 /* we make userspace set this right, 498 * so there is no misunderstanding 499 */ 500 return -EINVAL; 501 } 502 if (i != NF_BR_NUMHOOKS) 503 newinfo->hook_entry[i] = (struct ebt_entries *)e; 504 if (left < sizeof(struct ebt_entries)) 505 break; 506 offset += sizeof(struct ebt_entries); 507 } else { 508 if (left < sizeof(struct ebt_entry)) 509 break; 510 if (left < e->next_offset) 511 break; 512 if (e->next_offset < sizeof(struct ebt_entry)) 513 return -EINVAL; 514 offset += e->next_offset; 515 } 516 } 517 if (offset != limit) 518 return -EINVAL; 519 520 /* check if all valid hooks have a chain */ 521 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 522 if (!newinfo->hook_entry[i] && 523 (valid_hooks & (1 << i))) 524 return -EINVAL; 525 } 526 return 0; 527 } 528 529 /* this one is very careful, as it is the first function 530 * to parse the userspace data 531 */ 532 static inline int 533 ebt_check_entry_size_and_hooks(const struct ebt_entry *e, 534 const struct ebt_table_info *newinfo, 535 unsigned int *n, unsigned int *cnt, 536 unsigned int *totalcnt, unsigned int *udc_cnt) 537 { 538 int i; 539 540 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 541 if ((void *)e == (void *)newinfo->hook_entry[i]) 542 break; 543 } 544 /* beginning of a new chain 545 * if i == NF_BR_NUMHOOKS it must be a user defined chain 546 */ 547 if (i != NF_BR_NUMHOOKS || !e->bitmask) { 548 /* this checks if the previous chain has as many entries 549 * as it said it has 550 */ 551 if (*n != *cnt) 552 return -EINVAL; 553 554 if (((struct ebt_entries *)e)->policy != EBT_DROP && 555 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { 556 /* only RETURN from udc */ 557 if (i != NF_BR_NUMHOOKS || 558 ((struct ebt_entries *)e)->policy != EBT_RETURN) 559 return -EINVAL; 560 } 561 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ 562 (*udc_cnt)++; 563 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) 564 return -EINVAL; 565 *n = ((struct ebt_entries *)e)->nentries; 566 *cnt = 0; 567 return 0; 568 } 569 /* a plain old entry, heh */ 570 if (sizeof(struct ebt_entry) > e->watchers_offset || 571 e->watchers_offset > e->target_offset || 572 e->target_offset >= e->next_offset) 573 return -EINVAL; 574 575 /* this is not checked anywhere else */ 576 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) 577 return -EINVAL; 578 579 (*cnt)++; 580 (*totalcnt)++; 581 return 0; 582 } 583 584 struct ebt_cl_stack { 585 struct ebt_chainstack cs; 586 int from; 587 unsigned int hookmask; 588 }; 589 590 /* We need these positions to check that the jumps to a different part of the 591 * entries is a jump to the beginning of a new chain. 592 */ 593 static inline int 594 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, 595 unsigned int *n, struct ebt_cl_stack *udc) 596 { 597 int i; 598 599 /* we're only interested in chain starts */ 600 if (e->bitmask) 601 return 0; 602 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 603 if (newinfo->hook_entry[i] == (struct ebt_entries *)e) 604 break; 605 } 606 /* only care about udc */ 607 if (i != NF_BR_NUMHOOKS) 608 return 0; 609 610 udc[*n].cs.chaininfo = (struct ebt_entries *)e; 611 /* these initialisations are depended on later in check_chainloops() */ 612 udc[*n].cs.n = 0; 613 udc[*n].hookmask = 0; 614 615 (*n)++; 616 return 0; 617 } 618 619 static inline int 620 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i) 621 { 622 struct xt_mtdtor_param par; 623 624 if (i && (*i)-- == 0) 625 return 1; 626 627 par.net = net; 628 par.match = m->u.match; 629 par.matchinfo = m->data; 630 par.family = NFPROTO_BRIDGE; 631 if (par.match->destroy != NULL) 632 par.match->destroy(&par); 633 module_put(par.match->me); 634 return 0; 635 } 636 637 static inline int 638 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i) 639 { 640 struct xt_tgdtor_param par; 641 642 if (i && (*i)-- == 0) 643 return 1; 644 645 par.net = net; 646 par.target = w->u.watcher; 647 par.targinfo = w->data; 648 par.family = NFPROTO_BRIDGE; 649 if (par.target->destroy != NULL) 650 par.target->destroy(&par); 651 module_put(par.target->me); 652 return 0; 653 } 654 655 static inline int 656 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt) 657 { 658 struct xt_tgdtor_param par; 659 struct ebt_entry_target *t; 660 661 if (e->bitmask == 0) 662 return 0; 663 /* we're done */ 664 if (cnt && (*cnt)-- == 0) 665 return 1; 666 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL); 667 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL); 668 t = ebt_get_target(e); 669 670 par.net = net; 671 par.target = t->u.target; 672 par.targinfo = t->data; 673 par.family = NFPROTO_BRIDGE; 674 if (par.target->destroy != NULL) 675 par.target->destroy(&par); 676 module_put(par.target->me); 677 return 0; 678 } 679 680 static inline int 681 ebt_check_entry(struct ebt_entry *e, struct net *net, 682 const struct ebt_table_info *newinfo, 683 const char *name, unsigned int *cnt, 684 struct ebt_cl_stack *cl_s, unsigned int udc_cnt) 685 { 686 struct ebt_entry_target *t; 687 struct xt_target *target; 688 unsigned int i, j, hook = 0, hookmask = 0; 689 size_t gap; 690 int ret; 691 struct xt_mtchk_param mtpar; 692 struct xt_tgchk_param tgpar; 693 694 /* don't mess with the struct ebt_entries */ 695 if (e->bitmask == 0) 696 return 0; 697 698 if (e->bitmask & ~EBT_F_MASK) 699 return -EINVAL; 700 701 if (e->invflags & ~EBT_INV_MASK) 702 return -EINVAL; 703 704 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) 705 return -EINVAL; 706 707 /* what hook do we belong to? */ 708 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 709 if (!newinfo->hook_entry[i]) 710 continue; 711 if ((char *)newinfo->hook_entry[i] < (char *)e) 712 hook = i; 713 else 714 break; 715 } 716 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on 717 * a base chain 718 */ 719 if (i < NF_BR_NUMHOOKS) 720 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 721 else { 722 for (i = 0; i < udc_cnt; i++) 723 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) 724 break; 725 if (i == 0) 726 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 727 else 728 hookmask = cl_s[i - 1].hookmask; 729 } 730 i = 0; 731 732 memset(&mtpar, 0, sizeof(mtpar)); 733 memset(&tgpar, 0, sizeof(tgpar)); 734 mtpar.net = tgpar.net = net; 735 mtpar.table = tgpar.table = name; 736 mtpar.entryinfo = tgpar.entryinfo = e; 737 mtpar.hook_mask = tgpar.hook_mask = hookmask; 738 mtpar.family = tgpar.family = NFPROTO_BRIDGE; 739 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i); 740 if (ret != 0) 741 goto cleanup_matches; 742 j = 0; 743 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j); 744 if (ret != 0) 745 goto cleanup_watchers; 746 t = ebt_get_target(e); 747 gap = e->next_offset - e->target_offset; 748 749 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0); 750 if (IS_ERR(target)) { 751 ret = PTR_ERR(target); 752 goto cleanup_watchers; 753 } 754 755 /* Reject UNSPEC, xtables verdicts/return values are incompatible */ 756 if (target->family != NFPROTO_BRIDGE) { 757 module_put(target->me); 758 ret = -ENOENT; 759 goto cleanup_watchers; 760 } 761 762 t->u.target = target; 763 if (t->u.target == &ebt_standard_target) { 764 if (gap < sizeof(struct ebt_standard_target)) { 765 ret = -EFAULT; 766 goto cleanup_watchers; 767 } 768 if (((struct ebt_standard_target *)t)->verdict < 769 -NUM_STANDARD_TARGETS) { 770 ret = -EFAULT; 771 goto cleanup_watchers; 772 } 773 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) { 774 module_put(t->u.target->me); 775 ret = -EFAULT; 776 goto cleanup_watchers; 777 } 778 779 tgpar.target = target; 780 tgpar.targinfo = t->data; 781 ret = xt_check_target(&tgpar, t->target_size, 782 ntohs(e->ethproto), e->invflags & EBT_IPROTO); 783 if (ret < 0) { 784 module_put(target->me); 785 goto cleanup_watchers; 786 } 787 (*cnt)++; 788 return 0; 789 cleanup_watchers: 790 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j); 791 cleanup_matches: 792 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i); 793 return ret; 794 } 795 796 /* checks for loops and sets the hook mask for udc 797 * the hook mask for udc tells us from which base chains the udc can be 798 * accessed. This mask is a parameter to the check() functions of the extensions 799 */ 800 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s, 801 unsigned int udc_cnt, unsigned int hooknr, char *base) 802 { 803 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; 804 const struct ebt_entry *e = (struct ebt_entry *)chain->data; 805 const struct ebt_entry_target *t; 806 807 while (pos < nentries || chain_nr != -1) { 808 /* end of udc, go back one 'recursion' step */ 809 if (pos == nentries) { 810 /* put back values of the time when this chain was called */ 811 e = cl_s[chain_nr].cs.e; 812 if (cl_s[chain_nr].from != -1) 813 nentries = 814 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; 815 else 816 nentries = chain->nentries; 817 pos = cl_s[chain_nr].cs.n; 818 /* make sure we won't see a loop that isn't one */ 819 cl_s[chain_nr].cs.n = 0; 820 chain_nr = cl_s[chain_nr].from; 821 if (pos == nentries) 822 continue; 823 } 824 t = ebt_get_target_c(e); 825 if (strcmp(t->u.name, EBT_STANDARD_TARGET)) 826 goto letscontinue; 827 if (e->target_offset + sizeof(struct ebt_standard_target) > 828 e->next_offset) 829 return -1; 830 831 verdict = ((struct ebt_standard_target *)t)->verdict; 832 if (verdict >= 0) { /* jump to another chain */ 833 struct ebt_entries *hlp2 = 834 (struct ebt_entries *)(base + verdict); 835 for (i = 0; i < udc_cnt; i++) 836 if (hlp2 == cl_s[i].cs.chaininfo) 837 break; 838 /* bad destination or loop */ 839 if (i == udc_cnt) 840 return -1; 841 842 if (cl_s[i].cs.n) 843 return -1; 844 845 if (cl_s[i].hookmask & (1 << hooknr)) 846 goto letscontinue; 847 /* this can't be 0, so the loop test is correct */ 848 cl_s[i].cs.n = pos + 1; 849 pos = 0; 850 cl_s[i].cs.e = ebt_next_entry(e); 851 e = (struct ebt_entry *)(hlp2->data); 852 nentries = hlp2->nentries; 853 cl_s[i].from = chain_nr; 854 chain_nr = i; 855 /* this udc is accessible from the base chain for hooknr */ 856 cl_s[i].hookmask |= (1 << hooknr); 857 continue; 858 } 859 letscontinue: 860 e = ebt_next_entry(e); 861 pos++; 862 } 863 return 0; 864 } 865 866 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ 867 static int translate_table(struct net *net, const char *name, 868 struct ebt_table_info *newinfo) 869 { 870 unsigned int i, j, k, udc_cnt; 871 int ret; 872 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ 873 874 i = 0; 875 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i]) 876 i++; 877 if (i == NF_BR_NUMHOOKS) 878 return -EINVAL; 879 880 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) 881 return -EINVAL; 882 883 /* make sure chains are ordered after each other in same order 884 * as their corresponding hooks 885 */ 886 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { 887 if (!newinfo->hook_entry[j]) 888 continue; 889 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) 890 return -EINVAL; 891 892 i = j; 893 } 894 895 /* do some early checkings and initialize some things */ 896 i = 0; /* holds the expected nr. of entries for the chain */ 897 j = 0; /* holds the up to now counted entries for the chain */ 898 k = 0; /* holds the total nr. of entries, should equal 899 * newinfo->nentries afterwards 900 */ 901 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ 902 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 903 ebt_check_entry_size_and_hooks, newinfo, 904 &i, &j, &k, &udc_cnt); 905 906 if (ret != 0) 907 return ret; 908 909 if (i != j) 910 return -EINVAL; 911 912 if (k != newinfo->nentries) 913 return -EINVAL; 914 915 /* get the location of the udc, put them in an array 916 * while we're at it, allocate the chainstack 917 */ 918 if (udc_cnt) { 919 /* this will get free'd in do_replace()/ebt_register_table() 920 * if an error occurs 921 */ 922 newinfo->chainstack = 923 vmalloc(array_size(nr_cpu_ids, 924 sizeof(*(newinfo->chainstack)))); 925 if (!newinfo->chainstack) 926 return -ENOMEM; 927 for_each_possible_cpu(i) { 928 newinfo->chainstack[i] = 929 vmalloc_node(array_size(udc_cnt, 930 sizeof(*(newinfo->chainstack[0]))), 931 cpu_to_node(i)); 932 if (!newinfo->chainstack[i]) { 933 while (i) 934 vfree(newinfo->chainstack[--i]); 935 vfree(newinfo->chainstack); 936 newinfo->chainstack = NULL; 937 return -ENOMEM; 938 } 939 } 940 941 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s))); 942 if (!cl_s) 943 return -ENOMEM; 944 i = 0; /* the i'th udc */ 945 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 946 ebt_get_udc_positions, newinfo, &i, cl_s); 947 /* sanity check */ 948 if (i != udc_cnt) { 949 vfree(cl_s); 950 return -EFAULT; 951 } 952 } 953 954 /* Check for loops */ 955 for (i = 0; i < NF_BR_NUMHOOKS; i++) 956 if (newinfo->hook_entry[i]) 957 if (check_chainloops(newinfo->hook_entry[i], 958 cl_s, udc_cnt, i, newinfo->entries)) { 959 vfree(cl_s); 960 return -EINVAL; 961 } 962 963 /* we now know the following (along with E=mc²): 964 * - the nr of entries in each chain is right 965 * - the size of the allocated space is right 966 * - all valid hooks have a corresponding chain 967 * - there are no loops 968 * - wrong data can still be on the level of a single entry 969 * - could be there are jumps to places that are not the 970 * beginning of a chain. This can only occur in chains that 971 * are not accessible from any base chains, so we don't care. 972 */ 973 974 /* used to know what we need to clean up if something goes wrong */ 975 i = 0; 976 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 977 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt); 978 if (ret != 0) { 979 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 980 ebt_cleanup_entry, net, &i); 981 } 982 vfree(cl_s); 983 return ret; 984 } 985 986 /* called under write_lock */ 987 static void get_counters(const struct ebt_counter *oldcounters, 988 struct ebt_counter *counters, unsigned int nentries) 989 { 990 int i, cpu; 991 struct ebt_counter *counter_base; 992 993 /* counters of cpu 0 */ 994 memcpy(counters, oldcounters, 995 sizeof(struct ebt_counter) * nentries); 996 997 /* add other counters to those of cpu 0 */ 998 for_each_possible_cpu(cpu) { 999 if (cpu == 0) 1000 continue; 1001 counter_base = COUNTER_BASE(oldcounters, nentries, cpu); 1002 for (i = 0; i < nentries; i++) 1003 ADD_COUNTER(counters[i], counter_base[i].bcnt, 1004 counter_base[i].pcnt); 1005 } 1006 } 1007 1008 static int do_replace_finish(struct net *net, struct ebt_replace *repl, 1009 struct ebt_table_info *newinfo) 1010 { 1011 int ret; 1012 struct ebt_counter *counterstmp = NULL; 1013 /* used to be able to unlock earlier */ 1014 struct ebt_table_info *table; 1015 struct ebt_table *t; 1016 1017 /* the user wants counters back 1018 * the check on the size is done later, when we have the lock 1019 */ 1020 if (repl->num_counters) { 1021 unsigned long size = repl->num_counters * sizeof(*counterstmp); 1022 counterstmp = vmalloc(size); 1023 if (!counterstmp) 1024 return -ENOMEM; 1025 } 1026 1027 newinfo->chainstack = NULL; 1028 ret = ebt_verify_pointers(repl, newinfo); 1029 if (ret != 0) 1030 goto free_counterstmp; 1031 1032 ret = translate_table(net, repl->name, newinfo); 1033 1034 if (ret != 0) 1035 goto free_counterstmp; 1036 1037 t = find_table_lock(net, repl->name, &ret, &ebt_mutex); 1038 if (!t) { 1039 ret = -ENOENT; 1040 goto free_iterate; 1041 } 1042 1043 if (repl->valid_hooks != t->valid_hooks) 1044 goto free_unlock; 1045 1046 if (repl->num_counters && repl->num_counters != t->private->nentries) { 1047 ret = -EINVAL; 1048 goto free_unlock; 1049 } 1050 1051 /* we have the mutex lock, so no danger in reading this pointer */ 1052 table = t->private; 1053 /* make sure the table can only be rmmod'ed if it contains no rules */ 1054 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) { 1055 ret = -ENOENT; 1056 goto free_unlock; 1057 } else if (table->nentries && !newinfo->nentries) 1058 module_put(t->me); 1059 /* we need an atomic snapshot of the counters */ 1060 write_lock_bh(&t->lock); 1061 if (repl->num_counters) 1062 get_counters(t->private->counters, counterstmp, 1063 t->private->nentries); 1064 1065 t->private = newinfo; 1066 write_unlock_bh(&t->lock); 1067 mutex_unlock(&ebt_mutex); 1068 /* so, a user can change the chains while having messed up her counter 1069 * allocation. Only reason why this is done is because this way the lock 1070 * is held only once, while this doesn't bring the kernel into a 1071 * dangerous state. 1072 */ 1073 if (repl->num_counters && 1074 copy_to_user(repl->counters, counterstmp, 1075 array_size(repl->num_counters, sizeof(struct ebt_counter)))) { 1076 /* Silent error, can't fail, new table is already in place */ 1077 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n"); 1078 } 1079 1080 /* decrease module count and free resources */ 1081 EBT_ENTRY_ITERATE(table->entries, table->entries_size, 1082 ebt_cleanup_entry, net, NULL); 1083 1084 vfree(table->entries); 1085 ebt_free_table_info(table); 1086 vfree(table); 1087 vfree(counterstmp); 1088 1089 audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries, 1090 AUDIT_XT_OP_REPLACE, GFP_KERNEL); 1091 return ret; 1092 1093 free_unlock: 1094 mutex_unlock(&ebt_mutex); 1095 free_iterate: 1096 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 1097 ebt_cleanup_entry, net, NULL); 1098 free_counterstmp: 1099 vfree(counterstmp); 1100 /* can be initialized in translate_table() */ 1101 ebt_free_table_info(newinfo); 1102 return ret; 1103 } 1104 1105 /* replace the table */ 1106 static int do_replace(struct net *net, sockptr_t arg, unsigned int len) 1107 { 1108 int ret, countersize; 1109 struct ebt_table_info *newinfo; 1110 struct ebt_replace tmp; 1111 1112 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) 1113 return -EFAULT; 1114 1115 if (len != sizeof(tmp) + tmp.entries_size) 1116 return -EINVAL; 1117 1118 if (tmp.entries_size == 0) 1119 return -EINVAL; 1120 1121 /* overflow check */ 1122 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / 1123 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) 1124 return -ENOMEM; 1125 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) 1126 return -ENOMEM; 1127 1128 tmp.name[sizeof(tmp.name) - 1] = 0; 1129 1130 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; 1131 newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT); 1132 if (!newinfo) 1133 return -ENOMEM; 1134 1135 if (countersize) 1136 memset(newinfo->counters, 0, countersize); 1137 1138 newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT); 1139 if (!newinfo->entries) { 1140 ret = -ENOMEM; 1141 goto free_newinfo; 1142 } 1143 if (copy_from_user( 1144 newinfo->entries, tmp.entries, tmp.entries_size) != 0) { 1145 ret = -EFAULT; 1146 goto free_entries; 1147 } 1148 1149 ret = do_replace_finish(net, &tmp, newinfo); 1150 if (ret == 0) 1151 return ret; 1152 free_entries: 1153 vfree(newinfo->entries); 1154 free_newinfo: 1155 vfree(newinfo); 1156 return ret; 1157 } 1158 1159 static void __ebt_unregister_table(struct net *net, struct ebt_table *table) 1160 { 1161 mutex_lock(&ebt_mutex); 1162 list_del(&table->list); 1163 mutex_unlock(&ebt_mutex); 1164 audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries, 1165 AUDIT_XT_OP_UNREGISTER, GFP_KERNEL); 1166 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size, 1167 ebt_cleanup_entry, net, NULL); 1168 if (table->private->nentries) 1169 module_put(table->me); 1170 vfree(table->private->entries); 1171 ebt_free_table_info(table->private); 1172 vfree(table->private); 1173 kfree(table->ops); 1174 kfree(table); 1175 } 1176 1177 int ebt_register_table(struct net *net, const struct ebt_table *input_table, 1178 const struct nf_hook_ops *template_ops) 1179 { 1180 struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); 1181 struct ebt_table_info *newinfo; 1182 struct ebt_table *t, *table; 1183 struct nf_hook_ops *ops; 1184 unsigned int num_ops; 1185 struct ebt_replace_kernel *repl; 1186 int ret, i, countersize; 1187 void *p; 1188 1189 if (input_table == NULL || (repl = input_table->table) == NULL || 1190 repl->entries == NULL || repl->entries_size == 0 || 1191 repl->counters != NULL || input_table->private != NULL) 1192 return -EINVAL; 1193 1194 /* Don't add one table to multiple lists. */ 1195 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL); 1196 if (!table) { 1197 ret = -ENOMEM; 1198 goto out; 1199 } 1200 1201 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids; 1202 newinfo = vmalloc(sizeof(*newinfo) + countersize); 1203 ret = -ENOMEM; 1204 if (!newinfo) 1205 goto free_table; 1206 1207 p = vmalloc(repl->entries_size); 1208 if (!p) 1209 goto free_newinfo; 1210 1211 memcpy(p, repl->entries, repl->entries_size); 1212 newinfo->entries = p; 1213 1214 newinfo->entries_size = repl->entries_size; 1215 newinfo->nentries = repl->nentries; 1216 1217 if (countersize) 1218 memset(newinfo->counters, 0, countersize); 1219 1220 /* fill in newinfo and parse the entries */ 1221 newinfo->chainstack = NULL; 1222 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1223 if ((repl->valid_hooks & (1 << i)) == 0) 1224 newinfo->hook_entry[i] = NULL; 1225 else 1226 newinfo->hook_entry[i] = p + 1227 ((char *)repl->hook_entry[i] - repl->entries); 1228 } 1229 ret = translate_table(net, repl->name, newinfo); 1230 if (ret != 0) 1231 goto free_chainstack; 1232 1233 table->private = newinfo; 1234 rwlock_init(&table->lock); 1235 mutex_lock(&ebt_mutex); 1236 list_for_each_entry(t, &ebt_net->tables, list) { 1237 if (strcmp(t->name, table->name) == 0) { 1238 ret = -EEXIST; 1239 goto free_unlock; 1240 } 1241 } 1242 1243 /* Hold a reference count if the chains aren't empty */ 1244 if (newinfo->nentries && !try_module_get(table->me)) { 1245 ret = -ENOENT; 1246 goto free_unlock; 1247 } 1248 1249 num_ops = hweight32(table->valid_hooks); 1250 if (num_ops == 0) { 1251 ret = -EINVAL; 1252 goto free_unlock; 1253 } 1254 1255 ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL); 1256 if (!ops) { 1257 ret = -ENOMEM; 1258 if (newinfo->nentries) 1259 module_put(table->me); 1260 goto free_unlock; 1261 } 1262 1263 for (i = 0; i < num_ops; i++) 1264 ops[i].priv = table; 1265 1266 list_add(&table->list, &ebt_net->tables); 1267 mutex_unlock(&ebt_mutex); 1268 1269 table->ops = ops; 1270 ret = nf_register_net_hooks(net, ops, num_ops); 1271 if (ret) 1272 __ebt_unregister_table(net, table); 1273 1274 audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries, 1275 AUDIT_XT_OP_REGISTER, GFP_KERNEL); 1276 return ret; 1277 free_unlock: 1278 mutex_unlock(&ebt_mutex); 1279 free_chainstack: 1280 ebt_free_table_info(newinfo); 1281 vfree(newinfo->entries); 1282 free_newinfo: 1283 vfree(newinfo); 1284 free_table: 1285 kfree(table); 1286 out: 1287 return ret; 1288 } 1289 1290 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net)) 1291 { 1292 struct ebt_template *tmpl; 1293 1294 mutex_lock(&ebt_mutex); 1295 list_for_each_entry(tmpl, &template_tables, list) { 1296 if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) { 1297 mutex_unlock(&ebt_mutex); 1298 return -EEXIST; 1299 } 1300 } 1301 1302 tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL); 1303 if (!tmpl) { 1304 mutex_unlock(&ebt_mutex); 1305 return -ENOMEM; 1306 } 1307 1308 tmpl->table_init = table_init; 1309 strscpy(tmpl->name, t->name, sizeof(tmpl->name)); 1310 tmpl->owner = t->me; 1311 list_add(&tmpl->list, &template_tables); 1312 1313 mutex_unlock(&ebt_mutex); 1314 return 0; 1315 } 1316 EXPORT_SYMBOL(ebt_register_template); 1317 1318 void ebt_unregister_template(const struct ebt_table *t) 1319 { 1320 struct ebt_template *tmpl; 1321 1322 mutex_lock(&ebt_mutex); 1323 list_for_each_entry(tmpl, &template_tables, list) { 1324 if (strcmp(t->name, tmpl->name)) 1325 continue; 1326 1327 list_del(&tmpl->list); 1328 mutex_unlock(&ebt_mutex); 1329 kfree(tmpl); 1330 return; 1331 } 1332 1333 mutex_unlock(&ebt_mutex); 1334 WARN_ON_ONCE(1); 1335 } 1336 EXPORT_SYMBOL(ebt_unregister_template); 1337 1338 static struct ebt_table *__ebt_find_table(struct net *net, const char *name) 1339 { 1340 struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); 1341 struct ebt_table *t; 1342 1343 mutex_lock(&ebt_mutex); 1344 1345 list_for_each_entry(t, &ebt_net->tables, list) { 1346 if (strcmp(t->name, name) == 0) { 1347 mutex_unlock(&ebt_mutex); 1348 return t; 1349 } 1350 } 1351 1352 mutex_unlock(&ebt_mutex); 1353 return NULL; 1354 } 1355 1356 void ebt_unregister_table_pre_exit(struct net *net, const char *name) 1357 { 1358 struct ebt_table *table = __ebt_find_table(net, name); 1359 1360 if (table) 1361 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks)); 1362 } 1363 EXPORT_SYMBOL(ebt_unregister_table_pre_exit); 1364 1365 void ebt_unregister_table(struct net *net, const char *name) 1366 { 1367 struct ebt_table *table = __ebt_find_table(net, name); 1368 1369 if (table) 1370 __ebt_unregister_table(net, table); 1371 } 1372 1373 /* userspace just supplied us with counters */ 1374 static int do_update_counters(struct net *net, const char *name, 1375 struct ebt_counter __user *counters, 1376 unsigned int num_counters, unsigned int len) 1377 { 1378 int i, ret; 1379 struct ebt_counter *tmp; 1380 struct ebt_table *t; 1381 1382 if (num_counters == 0) 1383 return -EINVAL; 1384 1385 tmp = vmalloc(array_size(num_counters, sizeof(*tmp))); 1386 if (!tmp) 1387 return -ENOMEM; 1388 1389 t = find_table_lock(net, name, &ret, &ebt_mutex); 1390 if (!t) 1391 goto free_tmp; 1392 1393 if (num_counters != t->private->nentries) { 1394 ret = -EINVAL; 1395 goto unlock_mutex; 1396 } 1397 1398 if (copy_from_user(tmp, counters, 1399 array_size(num_counters, sizeof(*counters)))) { 1400 ret = -EFAULT; 1401 goto unlock_mutex; 1402 } 1403 1404 /* we want an atomic add of the counters */ 1405 write_lock_bh(&t->lock); 1406 1407 /* we add to the counters of the first cpu */ 1408 for (i = 0; i < num_counters; i++) 1409 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt); 1410 1411 write_unlock_bh(&t->lock); 1412 ret = 0; 1413 unlock_mutex: 1414 mutex_unlock(&ebt_mutex); 1415 free_tmp: 1416 vfree(tmp); 1417 return ret; 1418 } 1419 1420 static int update_counters(struct net *net, sockptr_t arg, unsigned int len) 1421 { 1422 struct ebt_replace hlp; 1423 1424 if (copy_from_sockptr(&hlp, arg, sizeof(hlp))) 1425 return -EFAULT; 1426 1427 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 1428 return -EINVAL; 1429 1430 return do_update_counters(net, hlp.name, hlp.counters, 1431 hlp.num_counters, len); 1432 } 1433 1434 static inline int ebt_obj_to_user(char __user *um, const char *_name, 1435 const char *data, int entrysize, 1436 int usersize, int datasize, u8 revision) 1437 { 1438 char name[EBT_EXTENSION_MAXNAMELEN] = {0}; 1439 1440 /* ebtables expects 31 bytes long names but xt_match names are 29 bytes 1441 * long. Copy 29 bytes and fill remaining bytes with zeroes. 1442 */ 1443 strlcpy(name, _name, sizeof(name)); 1444 if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) || 1445 put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) || 1446 put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) || 1447 xt_data_to_user(um + entrysize, data, usersize, datasize, 1448 XT_ALIGN(datasize))) 1449 return -EFAULT; 1450 1451 return 0; 1452 } 1453 1454 static inline int ebt_match_to_user(const struct ebt_entry_match *m, 1455 const char *base, char __user *ubase) 1456 { 1457 return ebt_obj_to_user(ubase + ((char *)m - base), 1458 m->u.match->name, m->data, sizeof(*m), 1459 m->u.match->usersize, m->match_size, 1460 m->u.match->revision); 1461 } 1462 1463 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w, 1464 const char *base, char __user *ubase) 1465 { 1466 return ebt_obj_to_user(ubase + ((char *)w - base), 1467 w->u.watcher->name, w->data, sizeof(*w), 1468 w->u.watcher->usersize, w->watcher_size, 1469 w->u.watcher->revision); 1470 } 1471 1472 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base, 1473 char __user *ubase) 1474 { 1475 int ret; 1476 char __user *hlp; 1477 const struct ebt_entry_target *t; 1478 1479 if (e->bitmask == 0) { 1480 /* special case !EBT_ENTRY_OR_ENTRIES */ 1481 if (copy_to_user(ubase + ((char *)e - base), e, 1482 sizeof(struct ebt_entries))) 1483 return -EFAULT; 1484 return 0; 1485 } 1486 1487 if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e))) 1488 return -EFAULT; 1489 1490 hlp = ubase + (((char *)e + e->target_offset) - base); 1491 t = ebt_get_target_c(e); 1492 1493 ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase); 1494 if (ret != 0) 1495 return ret; 1496 ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase); 1497 if (ret != 0) 1498 return ret; 1499 ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t), 1500 t->u.target->usersize, t->target_size, 1501 t->u.target->revision); 1502 if (ret != 0) 1503 return ret; 1504 1505 return 0; 1506 } 1507 1508 static int copy_counters_to_user(struct ebt_table *t, 1509 const struct ebt_counter *oldcounters, 1510 void __user *user, unsigned int num_counters, 1511 unsigned int nentries) 1512 { 1513 struct ebt_counter *counterstmp; 1514 int ret = 0; 1515 1516 /* userspace might not need the counters */ 1517 if (num_counters == 0) 1518 return 0; 1519 1520 if (num_counters != nentries) 1521 return -EINVAL; 1522 1523 counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp))); 1524 if (!counterstmp) 1525 return -ENOMEM; 1526 1527 write_lock_bh(&t->lock); 1528 get_counters(oldcounters, counterstmp, nentries); 1529 write_unlock_bh(&t->lock); 1530 1531 if (copy_to_user(user, counterstmp, 1532 array_size(nentries, sizeof(struct ebt_counter)))) 1533 ret = -EFAULT; 1534 vfree(counterstmp); 1535 return ret; 1536 } 1537 1538 /* called with ebt_mutex locked */ 1539 static int copy_everything_to_user(struct ebt_table *t, void __user *user, 1540 const int *len, int cmd) 1541 { 1542 struct ebt_replace tmp; 1543 const struct ebt_counter *oldcounters; 1544 unsigned int entries_size, nentries; 1545 int ret; 1546 char *entries; 1547 1548 if (cmd == EBT_SO_GET_ENTRIES) { 1549 entries_size = t->private->entries_size; 1550 nentries = t->private->nentries; 1551 entries = t->private->entries; 1552 oldcounters = t->private->counters; 1553 } else { 1554 entries_size = t->table->entries_size; 1555 nentries = t->table->nentries; 1556 entries = t->table->entries; 1557 oldcounters = t->table->counters; 1558 } 1559 1560 if (copy_from_user(&tmp, user, sizeof(tmp))) 1561 return -EFAULT; 1562 1563 if (*len != sizeof(struct ebt_replace) + entries_size + 1564 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0)) 1565 return -EINVAL; 1566 1567 if (tmp.nentries != nentries) 1568 return -EINVAL; 1569 1570 if (tmp.entries_size != entries_size) 1571 return -EINVAL; 1572 1573 ret = copy_counters_to_user(t, oldcounters, tmp.counters, 1574 tmp.num_counters, nentries); 1575 if (ret) 1576 return ret; 1577 1578 /* set the match/watcher/target names right */ 1579 return EBT_ENTRY_ITERATE(entries, entries_size, 1580 ebt_entry_to_user, entries, tmp.entries); 1581 } 1582 1583 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1584 /* 32 bit-userspace compatibility definitions. */ 1585 struct compat_ebt_replace { 1586 char name[EBT_TABLE_MAXNAMELEN]; 1587 compat_uint_t valid_hooks; 1588 compat_uint_t nentries; 1589 compat_uint_t entries_size; 1590 /* start of the chains */ 1591 compat_uptr_t hook_entry[NF_BR_NUMHOOKS]; 1592 /* nr of counters userspace expects back */ 1593 compat_uint_t num_counters; 1594 /* where the kernel will put the old counters. */ 1595 compat_uptr_t counters; 1596 compat_uptr_t entries; 1597 }; 1598 1599 /* struct ebt_entry_match, _target and _watcher have same layout */ 1600 struct compat_ebt_entry_mwt { 1601 union { 1602 struct { 1603 char name[EBT_EXTENSION_MAXNAMELEN]; 1604 u8 revision; 1605 }; 1606 compat_uptr_t ptr; 1607 } u; 1608 compat_uint_t match_size; 1609 compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace)); 1610 }; 1611 1612 /* account for possible padding between match_size and ->data */ 1613 static int ebt_compat_entry_padsize(void) 1614 { 1615 BUILD_BUG_ON(sizeof(struct ebt_entry_match) < 1616 sizeof(struct compat_ebt_entry_mwt)); 1617 return (int) sizeof(struct ebt_entry_match) - 1618 sizeof(struct compat_ebt_entry_mwt); 1619 } 1620 1621 static int ebt_compat_match_offset(const struct xt_match *match, 1622 unsigned int userlen) 1623 { 1624 /* ebt_among needs special handling. The kernel .matchsize is 1625 * set to -1 at registration time; at runtime an EBT_ALIGN()ed 1626 * value is expected. 1627 * Example: userspace sends 4500, ebt_among.c wants 4504. 1628 */ 1629 if (unlikely(match->matchsize == -1)) 1630 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen); 1631 return xt_compat_match_offset(match); 1632 } 1633 1634 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr, 1635 unsigned int *size) 1636 { 1637 const struct xt_match *match = m->u.match; 1638 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1639 int off = ebt_compat_match_offset(match, m->match_size); 1640 compat_uint_t msize = m->match_size - off; 1641 1642 if (WARN_ON(off >= m->match_size)) 1643 return -EINVAL; 1644 1645 if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) || 1646 put_user(match->revision, &cm->u.revision) || 1647 put_user(msize, &cm->match_size)) 1648 return -EFAULT; 1649 1650 if (match->compat_to_user) { 1651 if (match->compat_to_user(cm->data, m->data)) 1652 return -EFAULT; 1653 } else { 1654 if (xt_data_to_user(cm->data, m->data, match->usersize, msize, 1655 COMPAT_XT_ALIGN(msize))) 1656 return -EFAULT; 1657 } 1658 1659 *size -= ebt_compat_entry_padsize() + off; 1660 *dstptr = cm->data; 1661 *dstptr += msize; 1662 return 0; 1663 } 1664 1665 static int compat_target_to_user(struct ebt_entry_target *t, 1666 void __user **dstptr, 1667 unsigned int *size) 1668 { 1669 const struct xt_target *target = t->u.target; 1670 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1671 int off = xt_compat_target_offset(target); 1672 compat_uint_t tsize = t->target_size - off; 1673 1674 if (WARN_ON(off >= t->target_size)) 1675 return -EINVAL; 1676 1677 if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) || 1678 put_user(target->revision, &cm->u.revision) || 1679 put_user(tsize, &cm->match_size)) 1680 return -EFAULT; 1681 1682 if (target->compat_to_user) { 1683 if (target->compat_to_user(cm->data, t->data)) 1684 return -EFAULT; 1685 } else { 1686 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize, 1687 COMPAT_XT_ALIGN(tsize))) 1688 return -EFAULT; 1689 } 1690 1691 *size -= ebt_compat_entry_padsize() + off; 1692 *dstptr = cm->data; 1693 *dstptr += tsize; 1694 return 0; 1695 } 1696 1697 static int compat_watcher_to_user(struct ebt_entry_watcher *w, 1698 void __user **dstptr, 1699 unsigned int *size) 1700 { 1701 return compat_target_to_user((struct ebt_entry_target *)w, 1702 dstptr, size); 1703 } 1704 1705 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr, 1706 unsigned int *size) 1707 { 1708 struct ebt_entry_target *t; 1709 struct ebt_entry __user *ce; 1710 u32 watchers_offset, target_offset, next_offset; 1711 compat_uint_t origsize; 1712 int ret; 1713 1714 if (e->bitmask == 0) { 1715 if (*size < sizeof(struct ebt_entries)) 1716 return -EINVAL; 1717 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries))) 1718 return -EFAULT; 1719 1720 *dstptr += sizeof(struct ebt_entries); 1721 *size -= sizeof(struct ebt_entries); 1722 return 0; 1723 } 1724 1725 if (*size < sizeof(*ce)) 1726 return -EINVAL; 1727 1728 ce = *dstptr; 1729 if (copy_to_user(ce, e, sizeof(*ce))) 1730 return -EFAULT; 1731 1732 origsize = *size; 1733 *dstptr += sizeof(*ce); 1734 1735 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size); 1736 if (ret) 1737 return ret; 1738 watchers_offset = e->watchers_offset - (origsize - *size); 1739 1740 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size); 1741 if (ret) 1742 return ret; 1743 target_offset = e->target_offset - (origsize - *size); 1744 1745 t = ebt_get_target(e); 1746 1747 ret = compat_target_to_user(t, dstptr, size); 1748 if (ret) 1749 return ret; 1750 next_offset = e->next_offset - (origsize - *size); 1751 1752 if (put_user(watchers_offset, &ce->watchers_offset) || 1753 put_user(target_offset, &ce->target_offset) || 1754 put_user(next_offset, &ce->next_offset)) 1755 return -EFAULT; 1756 1757 *size -= sizeof(*ce); 1758 return 0; 1759 } 1760 1761 static int compat_calc_match(struct ebt_entry_match *m, int *off) 1762 { 1763 *off += ebt_compat_match_offset(m->u.match, m->match_size); 1764 *off += ebt_compat_entry_padsize(); 1765 return 0; 1766 } 1767 1768 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off) 1769 { 1770 *off += xt_compat_target_offset(w->u.watcher); 1771 *off += ebt_compat_entry_padsize(); 1772 return 0; 1773 } 1774 1775 static int compat_calc_entry(const struct ebt_entry *e, 1776 const struct ebt_table_info *info, 1777 const void *base, 1778 struct compat_ebt_replace *newinfo) 1779 { 1780 const struct ebt_entry_target *t; 1781 unsigned int entry_offset; 1782 int off, ret, i; 1783 1784 if (e->bitmask == 0) 1785 return 0; 1786 1787 off = 0; 1788 entry_offset = (void *)e - base; 1789 1790 EBT_MATCH_ITERATE(e, compat_calc_match, &off); 1791 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off); 1792 1793 t = ebt_get_target_c(e); 1794 1795 off += xt_compat_target_offset(t->u.target); 1796 off += ebt_compat_entry_padsize(); 1797 1798 newinfo->entries_size -= off; 1799 1800 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off); 1801 if (ret) 1802 return ret; 1803 1804 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1805 const void *hookptr = info->hook_entry[i]; 1806 if (info->hook_entry[i] && 1807 (e < (struct ebt_entry *)(base - hookptr))) { 1808 newinfo->hook_entry[i] -= off; 1809 pr_debug("0x%08X -> 0x%08X\n", 1810 newinfo->hook_entry[i] + off, 1811 newinfo->hook_entry[i]); 1812 } 1813 } 1814 1815 return 0; 1816 } 1817 1818 static int ebt_compat_init_offsets(unsigned int number) 1819 { 1820 if (number > INT_MAX) 1821 return -EINVAL; 1822 1823 /* also count the base chain policies */ 1824 number += NF_BR_NUMHOOKS; 1825 1826 return xt_compat_init_offsets(NFPROTO_BRIDGE, number); 1827 } 1828 1829 static int compat_table_info(const struct ebt_table_info *info, 1830 struct compat_ebt_replace *newinfo) 1831 { 1832 unsigned int size = info->entries_size; 1833 const void *entries = info->entries; 1834 int ret; 1835 1836 newinfo->entries_size = size; 1837 ret = ebt_compat_init_offsets(info->nentries); 1838 if (ret) 1839 return ret; 1840 1841 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, 1842 entries, newinfo); 1843 } 1844 1845 static int compat_copy_everything_to_user(struct ebt_table *t, 1846 void __user *user, int *len, int cmd) 1847 { 1848 struct compat_ebt_replace repl, tmp; 1849 struct ebt_counter *oldcounters; 1850 struct ebt_table_info tinfo; 1851 int ret; 1852 void __user *pos; 1853 1854 memset(&tinfo, 0, sizeof(tinfo)); 1855 1856 if (cmd == EBT_SO_GET_ENTRIES) { 1857 tinfo.entries_size = t->private->entries_size; 1858 tinfo.nentries = t->private->nentries; 1859 tinfo.entries = t->private->entries; 1860 oldcounters = t->private->counters; 1861 } else { 1862 tinfo.entries_size = t->table->entries_size; 1863 tinfo.nentries = t->table->nentries; 1864 tinfo.entries = t->table->entries; 1865 oldcounters = t->table->counters; 1866 } 1867 1868 if (copy_from_user(&tmp, user, sizeof(tmp))) 1869 return -EFAULT; 1870 1871 if (tmp.nentries != tinfo.nentries || 1872 (tmp.num_counters && tmp.num_counters != tinfo.nentries)) 1873 return -EINVAL; 1874 1875 memcpy(&repl, &tmp, sizeof(repl)); 1876 if (cmd == EBT_SO_GET_ENTRIES) 1877 ret = compat_table_info(t->private, &repl); 1878 else 1879 ret = compat_table_info(&tinfo, &repl); 1880 if (ret) 1881 return ret; 1882 1883 if (*len != sizeof(tmp) + repl.entries_size + 1884 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) { 1885 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n", 1886 *len, tinfo.entries_size, repl.entries_size); 1887 return -EINVAL; 1888 } 1889 1890 /* userspace might not need the counters */ 1891 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters), 1892 tmp.num_counters, tinfo.nentries); 1893 if (ret) 1894 return ret; 1895 1896 pos = compat_ptr(tmp.entries); 1897 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size, 1898 compat_copy_entry_to_user, &pos, &tmp.entries_size); 1899 } 1900 1901 struct ebt_entries_buf_state { 1902 char *buf_kern_start; /* kernel buffer to copy (translated) data to */ 1903 u32 buf_kern_len; /* total size of kernel buffer */ 1904 u32 buf_kern_offset; /* amount of data copied so far */ 1905 u32 buf_user_offset; /* read position in userspace buffer */ 1906 }; 1907 1908 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz) 1909 { 1910 state->buf_kern_offset += sz; 1911 return state->buf_kern_offset >= sz ? 0 : -EINVAL; 1912 } 1913 1914 static int ebt_buf_add(struct ebt_entries_buf_state *state, 1915 const void *data, unsigned int sz) 1916 { 1917 if (state->buf_kern_start == NULL) 1918 goto count_only; 1919 1920 if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len)) 1921 return -EINVAL; 1922 1923 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz); 1924 1925 count_only: 1926 state->buf_user_offset += sz; 1927 return ebt_buf_count(state, sz); 1928 } 1929 1930 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz) 1931 { 1932 char *b = state->buf_kern_start; 1933 1934 if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len)) 1935 return -EINVAL; 1936 1937 if (b != NULL && sz > 0) 1938 memset(b + state->buf_kern_offset, 0, sz); 1939 /* do not adjust ->buf_user_offset here, we added kernel-side padding */ 1940 return ebt_buf_count(state, sz); 1941 } 1942 1943 enum compat_mwt { 1944 EBT_COMPAT_MATCH, 1945 EBT_COMPAT_WATCHER, 1946 EBT_COMPAT_TARGET, 1947 }; 1948 1949 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt, 1950 enum compat_mwt compat_mwt, 1951 struct ebt_entries_buf_state *state, 1952 const unsigned char *base) 1953 { 1954 char name[EBT_EXTENSION_MAXNAMELEN]; 1955 struct xt_match *match; 1956 struct xt_target *wt; 1957 void *dst = NULL; 1958 int off, pad = 0; 1959 unsigned int size_kern, match_size = mwt->match_size; 1960 1961 if (strscpy(name, mwt->u.name, sizeof(name)) < 0) 1962 return -EINVAL; 1963 1964 if (state->buf_kern_start) 1965 dst = state->buf_kern_start + state->buf_kern_offset; 1966 1967 switch (compat_mwt) { 1968 case EBT_COMPAT_MATCH: 1969 match = xt_request_find_match(NFPROTO_BRIDGE, name, 1970 mwt->u.revision); 1971 if (IS_ERR(match)) 1972 return PTR_ERR(match); 1973 1974 off = ebt_compat_match_offset(match, match_size); 1975 if (dst) { 1976 if (match->compat_from_user) 1977 match->compat_from_user(dst, mwt->data); 1978 else 1979 memcpy(dst, mwt->data, match_size); 1980 } 1981 1982 size_kern = match->matchsize; 1983 if (unlikely(size_kern == -1)) 1984 size_kern = match_size; 1985 module_put(match->me); 1986 break; 1987 case EBT_COMPAT_WATCHER: 1988 case EBT_COMPAT_TARGET: 1989 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 1990 mwt->u.revision); 1991 if (IS_ERR(wt)) 1992 return PTR_ERR(wt); 1993 off = xt_compat_target_offset(wt); 1994 1995 if (dst) { 1996 if (wt->compat_from_user) 1997 wt->compat_from_user(dst, mwt->data); 1998 else 1999 memcpy(dst, mwt->data, match_size); 2000 } 2001 2002 size_kern = wt->targetsize; 2003 module_put(wt->me); 2004 break; 2005 2006 default: 2007 return -EINVAL; 2008 } 2009 2010 state->buf_kern_offset += match_size + off; 2011 state->buf_user_offset += match_size; 2012 pad = XT_ALIGN(size_kern) - size_kern; 2013 2014 if (pad > 0 && dst) { 2015 if (WARN_ON(state->buf_kern_len <= pad)) 2016 return -EINVAL; 2017 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad)) 2018 return -EINVAL; 2019 memset(dst + size_kern, 0, pad); 2020 } 2021 return off + match_size; 2022 } 2023 2024 /* return size of all matches, watchers or target, including necessary 2025 * alignment and padding. 2026 */ 2027 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32, 2028 unsigned int size_left, enum compat_mwt type, 2029 struct ebt_entries_buf_state *state, const void *base) 2030 { 2031 const char *buf = (const char *)match32; 2032 int growth = 0; 2033 2034 if (size_left == 0) 2035 return 0; 2036 2037 do { 2038 struct ebt_entry_match *match_kern; 2039 int ret; 2040 2041 if (size_left < sizeof(*match32)) 2042 return -EINVAL; 2043 2044 match_kern = (struct ebt_entry_match *) state->buf_kern_start; 2045 if (match_kern) { 2046 char *tmp; 2047 tmp = state->buf_kern_start + state->buf_kern_offset; 2048 match_kern = (struct ebt_entry_match *) tmp; 2049 } 2050 ret = ebt_buf_add(state, buf, sizeof(*match32)); 2051 if (ret < 0) 2052 return ret; 2053 size_left -= sizeof(*match32); 2054 2055 /* add padding before match->data (if any) */ 2056 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize()); 2057 if (ret < 0) 2058 return ret; 2059 2060 if (match32->match_size > size_left) 2061 return -EINVAL; 2062 2063 size_left -= match32->match_size; 2064 2065 ret = compat_mtw_from_user(match32, type, state, base); 2066 if (ret < 0) 2067 return ret; 2068 2069 if (WARN_ON(ret < match32->match_size)) 2070 return -EINVAL; 2071 growth += ret - match32->match_size; 2072 growth += ebt_compat_entry_padsize(); 2073 2074 buf += sizeof(*match32); 2075 buf += match32->match_size; 2076 2077 if (match_kern) 2078 match_kern->match_size = ret; 2079 2080 match32 = (struct compat_ebt_entry_mwt *) buf; 2081 } while (size_left); 2082 2083 return growth; 2084 } 2085 2086 /* called for all ebt_entry structures. */ 2087 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base, 2088 unsigned int *total, 2089 struct ebt_entries_buf_state *state) 2090 { 2091 unsigned int i, j, startoff, next_expected_off, new_offset = 0; 2092 /* stores match/watchers/targets & offset of next struct ebt_entry: */ 2093 unsigned int offsets[4]; 2094 unsigned int *offsets_update = NULL; 2095 int ret; 2096 char *buf_start; 2097 2098 if (*total < sizeof(struct ebt_entries)) 2099 return -EINVAL; 2100 2101 if (!entry->bitmask) { 2102 *total -= sizeof(struct ebt_entries); 2103 return ebt_buf_add(state, entry, sizeof(struct ebt_entries)); 2104 } 2105 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry)) 2106 return -EINVAL; 2107 2108 startoff = state->buf_user_offset; 2109 /* pull in most part of ebt_entry, it does not need to be changed. */ 2110 ret = ebt_buf_add(state, entry, 2111 offsetof(struct ebt_entry, watchers_offset)); 2112 if (ret < 0) 2113 return ret; 2114 2115 offsets[0] = sizeof(struct ebt_entry); /* matches come first */ 2116 memcpy(&offsets[1], &entry->watchers_offset, 2117 sizeof(offsets) - sizeof(offsets[0])); 2118 2119 if (state->buf_kern_start) { 2120 buf_start = state->buf_kern_start + state->buf_kern_offset; 2121 offsets_update = (unsigned int *) buf_start; 2122 } 2123 ret = ebt_buf_add(state, &offsets[1], 2124 sizeof(offsets) - sizeof(offsets[0])); 2125 if (ret < 0) 2126 return ret; 2127 buf_start = (char *) entry; 2128 /* 0: matches offset, always follows ebt_entry. 2129 * 1: watchers offset, from ebt_entry structure 2130 * 2: target offset, from ebt_entry structure 2131 * 3: next ebt_entry offset, from ebt_entry structure 2132 * 2133 * offsets are relative to beginning of struct ebt_entry (i.e., 0). 2134 */ 2135 for (i = 0; i < 4 ; ++i) { 2136 if (offsets[i] > *total) 2137 return -EINVAL; 2138 2139 if (i < 3 && offsets[i] == *total) 2140 return -EINVAL; 2141 2142 if (i == 0) 2143 continue; 2144 if (offsets[i-1] > offsets[i]) 2145 return -EINVAL; 2146 } 2147 2148 for (i = 0, j = 1 ; j < 4 ; j++, i++) { 2149 struct compat_ebt_entry_mwt *match32; 2150 unsigned int size; 2151 char *buf = buf_start + offsets[i]; 2152 2153 if (offsets[i] > offsets[j]) 2154 return -EINVAL; 2155 2156 match32 = (struct compat_ebt_entry_mwt *) buf; 2157 size = offsets[j] - offsets[i]; 2158 ret = ebt_size_mwt(match32, size, i, state, base); 2159 if (ret < 0) 2160 return ret; 2161 new_offset += ret; 2162 if (offsets_update && new_offset) { 2163 pr_debug("change offset %d to %d\n", 2164 offsets_update[i], offsets[j] + new_offset); 2165 offsets_update[i] = offsets[j] + new_offset; 2166 } 2167 } 2168 2169 if (state->buf_kern_start == NULL) { 2170 unsigned int offset = buf_start - (char *) base; 2171 2172 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset); 2173 if (ret < 0) 2174 return ret; 2175 } 2176 2177 next_expected_off = state->buf_user_offset - startoff; 2178 if (next_expected_off != entry->next_offset) 2179 return -EINVAL; 2180 2181 if (*total < entry->next_offset) 2182 return -EINVAL; 2183 *total -= entry->next_offset; 2184 return 0; 2185 } 2186 2187 /* repl->entries_size is the size of the ebt_entry blob in userspace. 2188 * It might need more memory when copied to a 64 bit kernel in case 2189 * userspace is 32-bit. So, first task: find out how much memory is needed. 2190 * 2191 * Called before validation is performed. 2192 */ 2193 static int compat_copy_entries(unsigned char *data, unsigned int size_user, 2194 struct ebt_entries_buf_state *state) 2195 { 2196 unsigned int size_remaining = size_user; 2197 int ret; 2198 2199 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data, 2200 &size_remaining, state); 2201 if (ret < 0) 2202 return ret; 2203 2204 if (size_remaining) 2205 return -EINVAL; 2206 2207 return state->buf_kern_offset; 2208 } 2209 2210 2211 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, 2212 sockptr_t arg, unsigned int len) 2213 { 2214 struct compat_ebt_replace tmp; 2215 int i; 2216 2217 if (len < sizeof(tmp)) 2218 return -EINVAL; 2219 2220 if (copy_from_sockptr(&tmp, arg, sizeof(tmp))) 2221 return -EFAULT; 2222 2223 if (len != sizeof(tmp) + tmp.entries_size) 2224 return -EINVAL; 2225 2226 if (tmp.entries_size == 0) 2227 return -EINVAL; 2228 2229 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / 2230 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) 2231 return -ENOMEM; 2232 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) 2233 return -ENOMEM; 2234 2235 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry)); 2236 2237 /* starting with hook_entry, 32 vs. 64 bit structures are different */ 2238 for (i = 0; i < NF_BR_NUMHOOKS; i++) 2239 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]); 2240 2241 repl->num_counters = tmp.num_counters; 2242 repl->counters = compat_ptr(tmp.counters); 2243 repl->entries = compat_ptr(tmp.entries); 2244 return 0; 2245 } 2246 2247 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len) 2248 { 2249 int ret, i, countersize, size64; 2250 struct ebt_table_info *newinfo; 2251 struct ebt_replace tmp; 2252 struct ebt_entries_buf_state state; 2253 void *entries_tmp; 2254 2255 ret = compat_copy_ebt_replace_from_user(&tmp, arg, len); 2256 if (ret) { 2257 /* try real handler in case userland supplied needed padding */ 2258 if (ret == -EINVAL && do_replace(net, arg, len) == 0) 2259 ret = 0; 2260 return ret; 2261 } 2262 2263 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; 2264 newinfo = vmalloc(sizeof(*newinfo) + countersize); 2265 if (!newinfo) 2266 return -ENOMEM; 2267 2268 if (countersize) 2269 memset(newinfo->counters, 0, countersize); 2270 2271 memset(&state, 0, sizeof(state)); 2272 2273 newinfo->entries = vmalloc(tmp.entries_size); 2274 if (!newinfo->entries) { 2275 ret = -ENOMEM; 2276 goto free_newinfo; 2277 } 2278 if (copy_from_user( 2279 newinfo->entries, tmp.entries, tmp.entries_size) != 0) { 2280 ret = -EFAULT; 2281 goto free_entries; 2282 } 2283 2284 entries_tmp = newinfo->entries; 2285 2286 xt_compat_lock(NFPROTO_BRIDGE); 2287 2288 ret = ebt_compat_init_offsets(tmp.nentries); 2289 if (ret < 0) 2290 goto out_unlock; 2291 2292 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2293 if (ret < 0) 2294 goto out_unlock; 2295 2296 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n", 2297 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset, 2298 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size)); 2299 2300 size64 = ret; 2301 newinfo->entries = vmalloc(size64); 2302 if (!newinfo->entries) { 2303 vfree(entries_tmp); 2304 ret = -ENOMEM; 2305 goto out_unlock; 2306 } 2307 2308 memset(&state, 0, sizeof(state)); 2309 state.buf_kern_start = newinfo->entries; 2310 state.buf_kern_len = size64; 2311 2312 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2313 if (WARN_ON(ret < 0)) { 2314 vfree(entries_tmp); 2315 goto out_unlock; 2316 } 2317 2318 vfree(entries_tmp); 2319 tmp.entries_size = size64; 2320 2321 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 2322 char __user *usrptr; 2323 if (tmp.hook_entry[i]) { 2324 unsigned int delta; 2325 usrptr = (char __user *) tmp.hook_entry[i]; 2326 delta = usrptr - tmp.entries; 2327 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta); 2328 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr; 2329 } 2330 } 2331 2332 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2333 xt_compat_unlock(NFPROTO_BRIDGE); 2334 2335 ret = do_replace_finish(net, &tmp, newinfo); 2336 if (ret == 0) 2337 return ret; 2338 free_entries: 2339 vfree(newinfo->entries); 2340 free_newinfo: 2341 vfree(newinfo); 2342 return ret; 2343 out_unlock: 2344 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2345 xt_compat_unlock(NFPROTO_BRIDGE); 2346 goto free_entries; 2347 } 2348 2349 static int compat_update_counters(struct net *net, sockptr_t arg, 2350 unsigned int len) 2351 { 2352 struct compat_ebt_replace hlp; 2353 2354 if (copy_from_sockptr(&hlp, arg, sizeof(hlp))) 2355 return -EFAULT; 2356 2357 /* try real handler in case userland supplied needed padding */ 2358 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 2359 return update_counters(net, arg, len); 2360 2361 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters), 2362 hlp.num_counters, len); 2363 } 2364 2365 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd, 2366 void __user *user, int *len) 2367 { 2368 int ret; 2369 struct compat_ebt_replace tmp; 2370 struct ebt_table *t; 2371 struct net *net = sock_net(sk); 2372 2373 if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) && 2374 *len != sizeof(struct compat_ebt_replace)) 2375 return -EINVAL; 2376 2377 if (copy_from_user(&tmp, user, sizeof(tmp))) 2378 return -EFAULT; 2379 2380 tmp.name[sizeof(tmp.name) - 1] = '\0'; 2381 2382 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 2383 if (!t) 2384 return ret; 2385 2386 xt_compat_lock(NFPROTO_BRIDGE); 2387 switch (cmd) { 2388 case EBT_SO_GET_INFO: 2389 tmp.nentries = t->private->nentries; 2390 ret = compat_table_info(t->private, &tmp); 2391 if (ret) 2392 goto out; 2393 tmp.valid_hooks = t->valid_hooks; 2394 2395 if (copy_to_user(user, &tmp, *len) != 0) { 2396 ret = -EFAULT; 2397 break; 2398 } 2399 ret = 0; 2400 break; 2401 case EBT_SO_GET_INIT_INFO: 2402 tmp.nentries = t->table->nentries; 2403 tmp.entries_size = t->table->entries_size; 2404 tmp.valid_hooks = t->table->valid_hooks; 2405 2406 if (copy_to_user(user, &tmp, *len) != 0) { 2407 ret = -EFAULT; 2408 break; 2409 } 2410 ret = 0; 2411 break; 2412 case EBT_SO_GET_ENTRIES: 2413 case EBT_SO_GET_INIT_ENTRIES: 2414 /* try real handler first in case of userland-side padding. 2415 * in case we are dealing with an 'ordinary' 32 bit binary 2416 * without 64bit compatibility padding, this will fail right 2417 * after copy_from_user when the *len argument is validated. 2418 * 2419 * the compat_ variant needs to do one pass over the kernel 2420 * data set to adjust for size differences before it the check. 2421 */ 2422 if (copy_everything_to_user(t, user, len, cmd) == 0) 2423 ret = 0; 2424 else 2425 ret = compat_copy_everything_to_user(t, user, len, cmd); 2426 break; 2427 default: 2428 ret = -EINVAL; 2429 } 2430 out: 2431 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2432 xt_compat_unlock(NFPROTO_BRIDGE); 2433 mutex_unlock(&ebt_mutex); 2434 return ret; 2435 } 2436 #endif 2437 2438 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 2439 { 2440 struct net *net = sock_net(sk); 2441 struct ebt_replace tmp; 2442 struct ebt_table *t; 2443 int ret; 2444 2445 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2446 return -EPERM; 2447 2448 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 2449 /* try real handler in case userland supplied needed padding */ 2450 if (in_compat_syscall() && 2451 ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) || 2452 *len != sizeof(tmp))) 2453 return compat_do_ebt_get_ctl(sk, cmd, user, len); 2454 #endif 2455 2456 if (copy_from_user(&tmp, user, sizeof(tmp))) 2457 return -EFAULT; 2458 2459 tmp.name[sizeof(tmp.name) - 1] = '\0'; 2460 2461 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 2462 if (!t) 2463 return ret; 2464 2465 switch (cmd) { 2466 case EBT_SO_GET_INFO: 2467 case EBT_SO_GET_INIT_INFO: 2468 if (*len != sizeof(struct ebt_replace)) { 2469 ret = -EINVAL; 2470 mutex_unlock(&ebt_mutex); 2471 break; 2472 } 2473 if (cmd == EBT_SO_GET_INFO) { 2474 tmp.nentries = t->private->nentries; 2475 tmp.entries_size = t->private->entries_size; 2476 tmp.valid_hooks = t->valid_hooks; 2477 } else { 2478 tmp.nentries = t->table->nentries; 2479 tmp.entries_size = t->table->entries_size; 2480 tmp.valid_hooks = t->table->valid_hooks; 2481 } 2482 mutex_unlock(&ebt_mutex); 2483 if (copy_to_user(user, &tmp, *len) != 0) { 2484 ret = -EFAULT; 2485 break; 2486 } 2487 ret = 0; 2488 break; 2489 2490 case EBT_SO_GET_ENTRIES: 2491 case EBT_SO_GET_INIT_ENTRIES: 2492 ret = copy_everything_to_user(t, user, len, cmd); 2493 mutex_unlock(&ebt_mutex); 2494 break; 2495 2496 default: 2497 mutex_unlock(&ebt_mutex); 2498 ret = -EINVAL; 2499 } 2500 2501 return ret; 2502 } 2503 2504 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg, 2505 unsigned int len) 2506 { 2507 struct net *net = sock_net(sk); 2508 int ret; 2509 2510 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2511 return -EPERM; 2512 2513 switch (cmd) { 2514 case EBT_SO_SET_ENTRIES: 2515 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 2516 if (in_compat_syscall()) 2517 ret = compat_do_replace(net, arg, len); 2518 else 2519 #endif 2520 ret = do_replace(net, arg, len); 2521 break; 2522 case EBT_SO_SET_COUNTERS: 2523 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 2524 if (in_compat_syscall()) 2525 ret = compat_update_counters(net, arg, len); 2526 else 2527 #endif 2528 ret = update_counters(net, arg, len); 2529 break; 2530 default: 2531 ret = -EINVAL; 2532 } 2533 return ret; 2534 } 2535 2536 static struct nf_sockopt_ops ebt_sockopts = { 2537 .pf = PF_INET, 2538 .set_optmin = EBT_BASE_CTL, 2539 .set_optmax = EBT_SO_SET_MAX + 1, 2540 .set = do_ebt_set_ctl, 2541 .get_optmin = EBT_BASE_CTL, 2542 .get_optmax = EBT_SO_GET_MAX + 1, 2543 .get = do_ebt_get_ctl, 2544 .owner = THIS_MODULE, 2545 }; 2546 2547 static int __net_init ebt_pernet_init(struct net *net) 2548 { 2549 struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); 2550 2551 INIT_LIST_HEAD(&ebt_net->tables); 2552 return 0; 2553 } 2554 2555 static struct pernet_operations ebt_net_ops = { 2556 .init = ebt_pernet_init, 2557 .id = &ebt_pernet_id, 2558 .size = sizeof(struct ebt_pernet), 2559 }; 2560 2561 static int __init ebtables_init(void) 2562 { 2563 int ret; 2564 2565 ret = xt_register_target(&ebt_standard_target); 2566 if (ret < 0) 2567 return ret; 2568 ret = nf_register_sockopt(&ebt_sockopts); 2569 if (ret < 0) { 2570 xt_unregister_target(&ebt_standard_target); 2571 return ret; 2572 } 2573 2574 ret = register_pernet_subsys(&ebt_net_ops); 2575 if (ret < 0) { 2576 nf_unregister_sockopt(&ebt_sockopts); 2577 xt_unregister_target(&ebt_standard_target); 2578 return ret; 2579 } 2580 2581 return 0; 2582 } 2583 2584 static void ebtables_fini(void) 2585 { 2586 nf_unregister_sockopt(&ebt_sockopts); 2587 xt_unregister_target(&ebt_standard_target); 2588 unregister_pernet_subsys(&ebt_net_ops); 2589 } 2590 2591 EXPORT_SYMBOL(ebt_register_table); 2592 EXPORT_SYMBOL(ebt_unregister_table); 2593 EXPORT_SYMBOL(ebt_do_table); 2594 module_init(ebtables_init); 2595 module_exit(ebtables_fini); 2596 MODULE_LICENSE("GPL"); 2597