1 /* 2 * ebtables 3 * 4 * Author: 5 * Bart De Schuymer <bdschuym@pandora.be> 6 * 7 * ebtables.c,v 2.0, July, 2002 8 * 9 * This code is strongly inspired by the iptables code which is 10 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 #include <linux/kmod.h> 19 #include <linux/module.h> 20 #include <linux/vmalloc.h> 21 #include <linux/netfilter/x_tables.h> 22 #include <linux/netfilter_bridge/ebtables.h> 23 #include <linux/spinlock.h> 24 #include <linux/mutex.h> 25 #include <linux/slab.h> 26 #include <linux/uaccess.h> 27 #include <linux/smp.h> 28 #include <linux/cpumask.h> 29 #include <linux/audit.h> 30 #include <net/sock.h> 31 /* needed for logical [in,out]-dev filtering */ 32 #include "../br_private.h" 33 34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\ 35 "report to author: "format, ## args) 36 /* #define BUGPRINT(format, args...) */ 37 38 /* Each cpu has its own set of counters, so there is no need for write_lock in 39 * the softirq 40 * For reading or updating the counters, the user context needs to 41 * get a write_lock 42 */ 43 44 /* The size of each set of counters is altered to get cache alignment */ 45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) 46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter))) 47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \ 48 COUNTER_OFFSET(n) * cpu)) 49 50 51 52 static DEFINE_MUTEX(ebt_mutex); 53 54 #ifdef CONFIG_COMPAT 55 static void ebt_standard_compat_from_user(void *dst, const void *src) 56 { 57 int v = *(compat_int_t *)src; 58 59 if (v >= 0) 60 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v); 61 memcpy(dst, &v, sizeof(v)); 62 } 63 64 static int ebt_standard_compat_to_user(void __user *dst, const void *src) 65 { 66 compat_int_t cv = *(int *)src; 67 68 if (cv >= 0) 69 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv); 70 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 71 } 72 #endif 73 74 75 static struct xt_target ebt_standard_target = { 76 .name = "standard", 77 .revision = 0, 78 .family = NFPROTO_BRIDGE, 79 .targetsize = sizeof(int), 80 #ifdef CONFIG_COMPAT 81 .compatsize = sizeof(compat_int_t), 82 .compat_from_user = ebt_standard_compat_from_user, 83 .compat_to_user = ebt_standard_compat_to_user, 84 #endif 85 }; 86 87 static inline int 88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb, 89 struct xt_action_param *par) 90 { 91 par->target = w->u.watcher; 92 par->targinfo = w->data; 93 w->u.watcher->target(skb, par); 94 /* watchers don't give a verdict */ 95 return 0; 96 } 97 98 static inline int 99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb, 100 struct xt_action_param *par) 101 { 102 par->match = m->u.match; 103 par->matchinfo = m->data; 104 return !m->u.match->match(skb, par); 105 } 106 107 static inline int 108 ebt_dev_check(const char *entry, const struct net_device *device) 109 { 110 int i = 0; 111 const char *devname; 112 113 if (*entry == '\0') 114 return 0; 115 if (!device) 116 return 1; 117 devname = device->name; 118 /* 1 is the wildcard token */ 119 while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i]) 120 i++; 121 return devname[i] != entry[i] && entry[i] != 1; 122 } 123 124 /* process standard matches */ 125 static inline int 126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb, 127 const struct net_device *in, const struct net_device *out) 128 { 129 const struct ethhdr *h = eth_hdr(skb); 130 const struct net_bridge_port *p; 131 __be16 ethproto; 132 133 if (skb_vlan_tag_present(skb)) 134 ethproto = htons(ETH_P_8021Q); 135 else 136 ethproto = h->h_proto; 137 138 if (e->bitmask & EBT_802_3) { 139 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto))) 140 return 1; 141 } else if (!(e->bitmask & EBT_NOPROTO) && 142 NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto)) 143 return 1; 144 145 if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in))) 146 return 1; 147 if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out))) 148 return 1; 149 /* rcu_read_lock()ed by nf_hook_thresh */ 150 if (in && (p = br_port_get_rcu(in)) != NULL && 151 NF_INVF(e, EBT_ILOGICALIN, 152 ebt_dev_check(e->logical_in, p->br->dev))) 153 return 1; 154 if (out && (p = br_port_get_rcu(out)) != NULL && 155 NF_INVF(e, EBT_ILOGICALOUT, 156 ebt_dev_check(e->logical_out, p->br->dev))) 157 return 1; 158 159 if (e->bitmask & EBT_SOURCEMAC) { 160 if (NF_INVF(e, EBT_ISOURCE, 161 !ether_addr_equal_masked(h->h_source, e->sourcemac, 162 e->sourcemsk))) 163 return 1; 164 } 165 if (e->bitmask & EBT_DESTMAC) { 166 if (NF_INVF(e, EBT_IDEST, 167 !ether_addr_equal_masked(h->h_dest, e->destmac, 168 e->destmsk))) 169 return 1; 170 } 171 return 0; 172 } 173 174 static inline 175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry) 176 { 177 return (void *)entry + entry->next_offset; 178 } 179 180 static inline const struct ebt_entry_target * 181 ebt_get_target_c(const struct ebt_entry *e) 182 { 183 return ebt_get_target((struct ebt_entry *)e); 184 } 185 186 /* Do some firewalling */ 187 unsigned int ebt_do_table(struct sk_buff *skb, 188 const struct nf_hook_state *state, 189 struct ebt_table *table) 190 { 191 unsigned int hook = state->hook; 192 int i, nentries; 193 struct ebt_entry *point; 194 struct ebt_counter *counter_base, *cb_base; 195 const struct ebt_entry_target *t; 196 int verdict, sp = 0; 197 struct ebt_chainstack *cs; 198 struct ebt_entries *chaininfo; 199 const char *base; 200 const struct ebt_table_info *private; 201 struct xt_action_param acpar; 202 203 acpar.state = state; 204 acpar.hotdrop = false; 205 206 read_lock_bh(&table->lock); 207 private = table->private; 208 cb_base = COUNTER_BASE(private->counters, private->nentries, 209 smp_processor_id()); 210 if (private->chainstack) 211 cs = private->chainstack[smp_processor_id()]; 212 else 213 cs = NULL; 214 chaininfo = private->hook_entry[hook]; 215 nentries = private->hook_entry[hook]->nentries; 216 point = (struct ebt_entry *)(private->hook_entry[hook]->data); 217 counter_base = cb_base + private->hook_entry[hook]->counter_offset; 218 /* base for chain jumps */ 219 base = private->entries; 220 i = 0; 221 while (i < nentries) { 222 if (ebt_basic_match(point, skb, state->in, state->out)) 223 goto letscontinue; 224 225 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0) 226 goto letscontinue; 227 if (acpar.hotdrop) { 228 read_unlock_bh(&table->lock); 229 return NF_DROP; 230 } 231 232 ADD_COUNTER(*(counter_base + i), 1, skb->len); 233 234 /* these should only watch: not modify, nor tell us 235 * what to do with the packet 236 */ 237 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar); 238 239 t = ebt_get_target_c(point); 240 /* standard target */ 241 if (!t->u.target->target) 242 verdict = ((struct ebt_standard_target *)t)->verdict; 243 else { 244 acpar.target = t->u.target; 245 acpar.targinfo = t->data; 246 verdict = t->u.target->target(skb, &acpar); 247 } 248 if (verdict == EBT_ACCEPT) { 249 read_unlock_bh(&table->lock); 250 return NF_ACCEPT; 251 } 252 if (verdict == EBT_DROP) { 253 read_unlock_bh(&table->lock); 254 return NF_DROP; 255 } 256 if (verdict == EBT_RETURN) { 257 letsreturn: 258 if (WARN(sp == 0, "RETURN on base chain")) { 259 /* act like this is EBT_CONTINUE */ 260 goto letscontinue; 261 } 262 263 sp--; 264 /* put all the local variables right */ 265 i = cs[sp].n; 266 chaininfo = cs[sp].chaininfo; 267 nentries = chaininfo->nentries; 268 point = cs[sp].e; 269 counter_base = cb_base + 270 chaininfo->counter_offset; 271 continue; 272 } 273 if (verdict == EBT_CONTINUE) 274 goto letscontinue; 275 276 if (WARN(verdict < 0, "bogus standard verdict\n")) { 277 read_unlock_bh(&table->lock); 278 return NF_DROP; 279 } 280 281 /* jump to a udc */ 282 cs[sp].n = i + 1; 283 cs[sp].chaininfo = chaininfo; 284 cs[sp].e = ebt_next_entry(point); 285 i = 0; 286 chaininfo = (struct ebt_entries *) (base + verdict); 287 288 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) { 289 read_unlock_bh(&table->lock); 290 return NF_DROP; 291 } 292 293 nentries = chaininfo->nentries; 294 point = (struct ebt_entry *)chaininfo->data; 295 counter_base = cb_base + chaininfo->counter_offset; 296 sp++; 297 continue; 298 letscontinue: 299 point = ebt_next_entry(point); 300 i++; 301 } 302 303 /* I actually like this :) */ 304 if (chaininfo->policy == EBT_RETURN) 305 goto letsreturn; 306 if (chaininfo->policy == EBT_ACCEPT) { 307 read_unlock_bh(&table->lock); 308 return NF_ACCEPT; 309 } 310 read_unlock_bh(&table->lock); 311 return NF_DROP; 312 } 313 314 /* If it succeeds, returns element and locks mutex */ 315 static inline void * 316 find_inlist_lock_noload(struct list_head *head, const char *name, int *error, 317 struct mutex *mutex) 318 { 319 struct { 320 struct list_head list; 321 char name[EBT_FUNCTION_MAXNAMELEN]; 322 } *e; 323 324 mutex_lock(mutex); 325 list_for_each_entry(e, head, list) { 326 if (strcmp(e->name, name) == 0) 327 return e; 328 } 329 *error = -ENOENT; 330 mutex_unlock(mutex); 331 return NULL; 332 } 333 334 static void * 335 find_inlist_lock(struct list_head *head, const char *name, const char *prefix, 336 int *error, struct mutex *mutex) 337 { 338 return try_then_request_module( 339 find_inlist_lock_noload(head, name, error, mutex), 340 "%s%s", prefix, name); 341 } 342 343 static inline struct ebt_table * 344 find_table_lock(struct net *net, const char *name, int *error, 345 struct mutex *mutex) 346 { 347 return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name, 348 "ebtable_", error, mutex); 349 } 350 351 static inline void ebt_free_table_info(struct ebt_table_info *info) 352 { 353 int i; 354 355 if (info->chainstack) { 356 for_each_possible_cpu(i) 357 vfree(info->chainstack[i]); 358 vfree(info->chainstack); 359 } 360 } 361 static inline int 362 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, 363 unsigned int *cnt) 364 { 365 const struct ebt_entry *e = par->entryinfo; 366 struct xt_match *match; 367 size_t left = ((char *)e + e->watchers_offset) - (char *)m; 368 int ret; 369 370 if (left < sizeof(struct ebt_entry_match) || 371 left - sizeof(struct ebt_entry_match) < m->match_size) 372 return -EINVAL; 373 374 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); 375 if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { 376 if (!IS_ERR(match)) 377 module_put(match->me); 378 request_module("ebt_%s", m->u.name); 379 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); 380 } 381 if (IS_ERR(match)) 382 return PTR_ERR(match); 383 m->u.match = match; 384 385 par->match = match; 386 par->matchinfo = m->data; 387 ret = xt_check_match(par, m->match_size, 388 e->ethproto, e->invflags & EBT_IPROTO); 389 if (ret < 0) { 390 module_put(match->me); 391 return ret; 392 } 393 394 (*cnt)++; 395 return 0; 396 } 397 398 static inline int 399 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par, 400 unsigned int *cnt) 401 { 402 const struct ebt_entry *e = par->entryinfo; 403 struct xt_target *watcher; 404 size_t left = ((char *)e + e->target_offset) - (char *)w; 405 int ret; 406 407 if (left < sizeof(struct ebt_entry_watcher) || 408 left - sizeof(struct ebt_entry_watcher) < w->watcher_size) 409 return -EINVAL; 410 411 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); 412 if (IS_ERR(watcher)) 413 return PTR_ERR(watcher); 414 415 if (watcher->family != NFPROTO_BRIDGE) { 416 module_put(watcher->me); 417 return -ENOENT; 418 } 419 420 w->u.watcher = watcher; 421 422 par->target = watcher; 423 par->targinfo = w->data; 424 ret = xt_check_target(par, w->watcher_size, 425 e->ethproto, e->invflags & EBT_IPROTO); 426 if (ret < 0) { 427 module_put(watcher->me); 428 return ret; 429 } 430 431 (*cnt)++; 432 return 0; 433 } 434 435 static int ebt_verify_pointers(const struct ebt_replace *repl, 436 struct ebt_table_info *newinfo) 437 { 438 unsigned int limit = repl->entries_size; 439 unsigned int valid_hooks = repl->valid_hooks; 440 unsigned int offset = 0; 441 int i; 442 443 for (i = 0; i < NF_BR_NUMHOOKS; i++) 444 newinfo->hook_entry[i] = NULL; 445 446 newinfo->entries_size = repl->entries_size; 447 newinfo->nentries = repl->nentries; 448 449 while (offset < limit) { 450 size_t left = limit - offset; 451 struct ebt_entry *e = (void *)newinfo->entries + offset; 452 453 if (left < sizeof(unsigned int)) 454 break; 455 456 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 457 if ((valid_hooks & (1 << i)) == 0) 458 continue; 459 if ((char __user *)repl->hook_entry[i] == 460 repl->entries + offset) 461 break; 462 } 463 464 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { 465 if (e->bitmask != 0) { 466 /* we make userspace set this right, 467 * so there is no misunderstanding 468 */ 469 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set " 470 "in distinguisher\n"); 471 return -EINVAL; 472 } 473 if (i != NF_BR_NUMHOOKS) 474 newinfo->hook_entry[i] = (struct ebt_entries *)e; 475 if (left < sizeof(struct ebt_entries)) 476 break; 477 offset += sizeof(struct ebt_entries); 478 } else { 479 if (left < sizeof(struct ebt_entry)) 480 break; 481 if (left < e->next_offset) 482 break; 483 if (e->next_offset < sizeof(struct ebt_entry)) 484 return -EINVAL; 485 offset += e->next_offset; 486 } 487 } 488 if (offset != limit) { 489 BUGPRINT("entries_size too small\n"); 490 return -EINVAL; 491 } 492 493 /* check if all valid hooks have a chain */ 494 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 495 if (!newinfo->hook_entry[i] && 496 (valid_hooks & (1 << i))) { 497 BUGPRINT("Valid hook without chain\n"); 498 return -EINVAL; 499 } 500 } 501 return 0; 502 } 503 504 /* this one is very careful, as it is the first function 505 * to parse the userspace data 506 */ 507 static inline int 508 ebt_check_entry_size_and_hooks(const struct ebt_entry *e, 509 const struct ebt_table_info *newinfo, 510 unsigned int *n, unsigned int *cnt, 511 unsigned int *totalcnt, unsigned int *udc_cnt) 512 { 513 int i; 514 515 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 516 if ((void *)e == (void *)newinfo->hook_entry[i]) 517 break; 518 } 519 /* beginning of a new chain 520 * if i == NF_BR_NUMHOOKS it must be a user defined chain 521 */ 522 if (i != NF_BR_NUMHOOKS || !e->bitmask) { 523 /* this checks if the previous chain has as many entries 524 * as it said it has 525 */ 526 if (*n != *cnt) { 527 BUGPRINT("nentries does not equal the nr of entries " 528 "in the chain\n"); 529 return -EINVAL; 530 } 531 if (((struct ebt_entries *)e)->policy != EBT_DROP && 532 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { 533 /* only RETURN from udc */ 534 if (i != NF_BR_NUMHOOKS || 535 ((struct ebt_entries *)e)->policy != EBT_RETURN) { 536 BUGPRINT("bad policy\n"); 537 return -EINVAL; 538 } 539 } 540 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ 541 (*udc_cnt)++; 542 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) { 543 BUGPRINT("counter_offset != totalcnt"); 544 return -EINVAL; 545 } 546 *n = ((struct ebt_entries *)e)->nentries; 547 *cnt = 0; 548 return 0; 549 } 550 /* a plain old entry, heh */ 551 if (sizeof(struct ebt_entry) > e->watchers_offset || 552 e->watchers_offset > e->target_offset || 553 e->target_offset >= e->next_offset) { 554 BUGPRINT("entry offsets not in right order\n"); 555 return -EINVAL; 556 } 557 /* this is not checked anywhere else */ 558 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) { 559 BUGPRINT("target size too small\n"); 560 return -EINVAL; 561 } 562 (*cnt)++; 563 (*totalcnt)++; 564 return 0; 565 } 566 567 struct ebt_cl_stack { 568 struct ebt_chainstack cs; 569 int from; 570 unsigned int hookmask; 571 }; 572 573 /* We need these positions to check that the jumps to a different part of the 574 * entries is a jump to the beginning of a new chain. 575 */ 576 static inline int 577 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, 578 unsigned int *n, struct ebt_cl_stack *udc) 579 { 580 int i; 581 582 /* we're only interested in chain starts */ 583 if (e->bitmask) 584 return 0; 585 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 586 if (newinfo->hook_entry[i] == (struct ebt_entries *)e) 587 break; 588 } 589 /* only care about udc */ 590 if (i != NF_BR_NUMHOOKS) 591 return 0; 592 593 udc[*n].cs.chaininfo = (struct ebt_entries *)e; 594 /* these initialisations are depended on later in check_chainloops() */ 595 udc[*n].cs.n = 0; 596 udc[*n].hookmask = 0; 597 598 (*n)++; 599 return 0; 600 } 601 602 static inline int 603 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i) 604 { 605 struct xt_mtdtor_param par; 606 607 if (i && (*i)-- == 0) 608 return 1; 609 610 par.net = net; 611 par.match = m->u.match; 612 par.matchinfo = m->data; 613 par.family = NFPROTO_BRIDGE; 614 if (par.match->destroy != NULL) 615 par.match->destroy(&par); 616 module_put(par.match->me); 617 return 0; 618 } 619 620 static inline int 621 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i) 622 { 623 struct xt_tgdtor_param par; 624 625 if (i && (*i)-- == 0) 626 return 1; 627 628 par.net = net; 629 par.target = w->u.watcher; 630 par.targinfo = w->data; 631 par.family = NFPROTO_BRIDGE; 632 if (par.target->destroy != NULL) 633 par.target->destroy(&par); 634 module_put(par.target->me); 635 return 0; 636 } 637 638 static inline int 639 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt) 640 { 641 struct xt_tgdtor_param par; 642 struct ebt_entry_target *t; 643 644 if (e->bitmask == 0) 645 return 0; 646 /* we're done */ 647 if (cnt && (*cnt)-- == 0) 648 return 1; 649 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL); 650 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL); 651 t = ebt_get_target(e); 652 653 par.net = net; 654 par.target = t->u.target; 655 par.targinfo = t->data; 656 par.family = NFPROTO_BRIDGE; 657 if (par.target->destroy != NULL) 658 par.target->destroy(&par); 659 module_put(par.target->me); 660 return 0; 661 } 662 663 static inline int 664 ebt_check_entry(struct ebt_entry *e, struct net *net, 665 const struct ebt_table_info *newinfo, 666 const char *name, unsigned int *cnt, 667 struct ebt_cl_stack *cl_s, unsigned int udc_cnt) 668 { 669 struct ebt_entry_target *t; 670 struct xt_target *target; 671 unsigned int i, j, hook = 0, hookmask = 0; 672 size_t gap; 673 int ret; 674 struct xt_mtchk_param mtpar; 675 struct xt_tgchk_param tgpar; 676 677 /* don't mess with the struct ebt_entries */ 678 if (e->bitmask == 0) 679 return 0; 680 681 if (e->bitmask & ~EBT_F_MASK) { 682 BUGPRINT("Unknown flag for bitmask\n"); 683 return -EINVAL; 684 } 685 if (e->invflags & ~EBT_INV_MASK) { 686 BUGPRINT("Unknown flag for inv bitmask\n"); 687 return -EINVAL; 688 } 689 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) { 690 BUGPRINT("NOPROTO & 802_3 not allowed\n"); 691 return -EINVAL; 692 } 693 /* what hook do we belong to? */ 694 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 695 if (!newinfo->hook_entry[i]) 696 continue; 697 if ((char *)newinfo->hook_entry[i] < (char *)e) 698 hook = i; 699 else 700 break; 701 } 702 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on 703 * a base chain 704 */ 705 if (i < NF_BR_NUMHOOKS) 706 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 707 else { 708 for (i = 0; i < udc_cnt; i++) 709 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) 710 break; 711 if (i == 0) 712 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 713 else 714 hookmask = cl_s[i - 1].hookmask; 715 } 716 i = 0; 717 718 memset(&mtpar, 0, sizeof(mtpar)); 719 memset(&tgpar, 0, sizeof(tgpar)); 720 mtpar.net = tgpar.net = net; 721 mtpar.table = tgpar.table = name; 722 mtpar.entryinfo = tgpar.entryinfo = e; 723 mtpar.hook_mask = tgpar.hook_mask = hookmask; 724 mtpar.family = tgpar.family = NFPROTO_BRIDGE; 725 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i); 726 if (ret != 0) 727 goto cleanup_matches; 728 j = 0; 729 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j); 730 if (ret != 0) 731 goto cleanup_watchers; 732 t = ebt_get_target(e); 733 gap = e->next_offset - e->target_offset; 734 735 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0); 736 if (IS_ERR(target)) { 737 ret = PTR_ERR(target); 738 goto cleanup_watchers; 739 } 740 741 /* Reject UNSPEC, xtables verdicts/return values are incompatible */ 742 if (target->family != NFPROTO_BRIDGE) { 743 module_put(target->me); 744 ret = -ENOENT; 745 goto cleanup_watchers; 746 } 747 748 t->u.target = target; 749 if (t->u.target == &ebt_standard_target) { 750 if (gap < sizeof(struct ebt_standard_target)) { 751 BUGPRINT("Standard target size too big\n"); 752 ret = -EFAULT; 753 goto cleanup_watchers; 754 } 755 if (((struct ebt_standard_target *)t)->verdict < 756 -NUM_STANDARD_TARGETS) { 757 BUGPRINT("Invalid standard target\n"); 758 ret = -EFAULT; 759 goto cleanup_watchers; 760 } 761 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) { 762 module_put(t->u.target->me); 763 ret = -EFAULT; 764 goto cleanup_watchers; 765 } 766 767 tgpar.target = target; 768 tgpar.targinfo = t->data; 769 ret = xt_check_target(&tgpar, t->target_size, 770 e->ethproto, e->invflags & EBT_IPROTO); 771 if (ret < 0) { 772 module_put(target->me); 773 goto cleanup_watchers; 774 } 775 (*cnt)++; 776 return 0; 777 cleanup_watchers: 778 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j); 779 cleanup_matches: 780 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i); 781 return ret; 782 } 783 784 /* checks for loops and sets the hook mask for udc 785 * the hook mask for udc tells us from which base chains the udc can be 786 * accessed. This mask is a parameter to the check() functions of the extensions 787 */ 788 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s, 789 unsigned int udc_cnt, unsigned int hooknr, char *base) 790 { 791 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; 792 const struct ebt_entry *e = (struct ebt_entry *)chain->data; 793 const struct ebt_entry_target *t; 794 795 while (pos < nentries || chain_nr != -1) { 796 /* end of udc, go back one 'recursion' step */ 797 if (pos == nentries) { 798 /* put back values of the time when this chain was called */ 799 e = cl_s[chain_nr].cs.e; 800 if (cl_s[chain_nr].from != -1) 801 nentries = 802 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; 803 else 804 nentries = chain->nentries; 805 pos = cl_s[chain_nr].cs.n; 806 /* make sure we won't see a loop that isn't one */ 807 cl_s[chain_nr].cs.n = 0; 808 chain_nr = cl_s[chain_nr].from; 809 if (pos == nentries) 810 continue; 811 } 812 t = ebt_get_target_c(e); 813 if (strcmp(t->u.name, EBT_STANDARD_TARGET)) 814 goto letscontinue; 815 if (e->target_offset + sizeof(struct ebt_standard_target) > 816 e->next_offset) { 817 BUGPRINT("Standard target size too big\n"); 818 return -1; 819 } 820 verdict = ((struct ebt_standard_target *)t)->verdict; 821 if (verdict >= 0) { /* jump to another chain */ 822 struct ebt_entries *hlp2 = 823 (struct ebt_entries *)(base + verdict); 824 for (i = 0; i < udc_cnt; i++) 825 if (hlp2 == cl_s[i].cs.chaininfo) 826 break; 827 /* bad destination or loop */ 828 if (i == udc_cnt) { 829 BUGPRINT("bad destination\n"); 830 return -1; 831 } 832 if (cl_s[i].cs.n) { 833 BUGPRINT("loop\n"); 834 return -1; 835 } 836 if (cl_s[i].hookmask & (1 << hooknr)) 837 goto letscontinue; 838 /* this can't be 0, so the loop test is correct */ 839 cl_s[i].cs.n = pos + 1; 840 pos = 0; 841 cl_s[i].cs.e = ebt_next_entry(e); 842 e = (struct ebt_entry *)(hlp2->data); 843 nentries = hlp2->nentries; 844 cl_s[i].from = chain_nr; 845 chain_nr = i; 846 /* this udc is accessible from the base chain for hooknr */ 847 cl_s[i].hookmask |= (1 << hooknr); 848 continue; 849 } 850 letscontinue: 851 e = ebt_next_entry(e); 852 pos++; 853 } 854 return 0; 855 } 856 857 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ 858 static int translate_table(struct net *net, const char *name, 859 struct ebt_table_info *newinfo) 860 { 861 unsigned int i, j, k, udc_cnt; 862 int ret; 863 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ 864 865 i = 0; 866 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i]) 867 i++; 868 if (i == NF_BR_NUMHOOKS) { 869 BUGPRINT("No valid hooks specified\n"); 870 return -EINVAL; 871 } 872 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) { 873 BUGPRINT("Chains don't start at beginning\n"); 874 return -EINVAL; 875 } 876 /* make sure chains are ordered after each other in same order 877 * as their corresponding hooks 878 */ 879 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { 880 if (!newinfo->hook_entry[j]) 881 continue; 882 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) { 883 BUGPRINT("Hook order must be followed\n"); 884 return -EINVAL; 885 } 886 i = j; 887 } 888 889 /* do some early checkings and initialize some things */ 890 i = 0; /* holds the expected nr. of entries for the chain */ 891 j = 0; /* holds the up to now counted entries for the chain */ 892 k = 0; /* holds the total nr. of entries, should equal 893 * newinfo->nentries afterwards 894 */ 895 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ 896 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 897 ebt_check_entry_size_and_hooks, newinfo, 898 &i, &j, &k, &udc_cnt); 899 900 if (ret != 0) 901 return ret; 902 903 if (i != j) { 904 BUGPRINT("nentries does not equal the nr of entries in the " 905 "(last) chain\n"); 906 return -EINVAL; 907 } 908 if (k != newinfo->nentries) { 909 BUGPRINT("Total nentries is wrong\n"); 910 return -EINVAL; 911 } 912 913 /* get the location of the udc, put them in an array 914 * while we're at it, allocate the chainstack 915 */ 916 if (udc_cnt) { 917 /* this will get free'd in do_replace()/ebt_register_table() 918 * if an error occurs 919 */ 920 newinfo->chainstack = 921 vmalloc(array_size(nr_cpu_ids, 922 sizeof(*(newinfo->chainstack)))); 923 if (!newinfo->chainstack) 924 return -ENOMEM; 925 for_each_possible_cpu(i) { 926 newinfo->chainstack[i] = 927 vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0])))); 928 if (!newinfo->chainstack[i]) { 929 while (i) 930 vfree(newinfo->chainstack[--i]); 931 vfree(newinfo->chainstack); 932 newinfo->chainstack = NULL; 933 return -ENOMEM; 934 } 935 } 936 937 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s))); 938 if (!cl_s) 939 return -ENOMEM; 940 i = 0; /* the i'th udc */ 941 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 942 ebt_get_udc_positions, newinfo, &i, cl_s); 943 /* sanity check */ 944 if (i != udc_cnt) { 945 BUGPRINT("i != udc_cnt\n"); 946 vfree(cl_s); 947 return -EFAULT; 948 } 949 } 950 951 /* Check for loops */ 952 for (i = 0; i < NF_BR_NUMHOOKS; i++) 953 if (newinfo->hook_entry[i]) 954 if (check_chainloops(newinfo->hook_entry[i], 955 cl_s, udc_cnt, i, newinfo->entries)) { 956 vfree(cl_s); 957 return -EINVAL; 958 } 959 960 /* we now know the following (along with E=mc²): 961 * - the nr of entries in each chain is right 962 * - the size of the allocated space is right 963 * - all valid hooks have a corresponding chain 964 * - there are no loops 965 * - wrong data can still be on the level of a single entry 966 * - could be there are jumps to places that are not the 967 * beginning of a chain. This can only occur in chains that 968 * are not accessible from any base chains, so we don't care. 969 */ 970 971 /* used to know what we need to clean up if something goes wrong */ 972 i = 0; 973 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 974 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt); 975 if (ret != 0) { 976 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 977 ebt_cleanup_entry, net, &i); 978 } 979 vfree(cl_s); 980 return ret; 981 } 982 983 /* called under write_lock */ 984 static void get_counters(const struct ebt_counter *oldcounters, 985 struct ebt_counter *counters, unsigned int nentries) 986 { 987 int i, cpu; 988 struct ebt_counter *counter_base; 989 990 /* counters of cpu 0 */ 991 memcpy(counters, oldcounters, 992 sizeof(struct ebt_counter) * nentries); 993 994 /* add other counters to those of cpu 0 */ 995 for_each_possible_cpu(cpu) { 996 if (cpu == 0) 997 continue; 998 counter_base = COUNTER_BASE(oldcounters, nentries, cpu); 999 for (i = 0; i < nentries; i++) 1000 ADD_COUNTER(counters[i], counter_base[i].pcnt, 1001 counter_base[i].bcnt); 1002 } 1003 } 1004 1005 static int do_replace_finish(struct net *net, struct ebt_replace *repl, 1006 struct ebt_table_info *newinfo) 1007 { 1008 int ret; 1009 struct ebt_counter *counterstmp = NULL; 1010 /* used to be able to unlock earlier */ 1011 struct ebt_table_info *table; 1012 struct ebt_table *t; 1013 1014 /* the user wants counters back 1015 * the check on the size is done later, when we have the lock 1016 */ 1017 if (repl->num_counters) { 1018 unsigned long size = repl->num_counters * sizeof(*counterstmp); 1019 counterstmp = vmalloc(size); 1020 if (!counterstmp) 1021 return -ENOMEM; 1022 } 1023 1024 newinfo->chainstack = NULL; 1025 ret = ebt_verify_pointers(repl, newinfo); 1026 if (ret != 0) 1027 goto free_counterstmp; 1028 1029 ret = translate_table(net, repl->name, newinfo); 1030 1031 if (ret != 0) 1032 goto free_counterstmp; 1033 1034 t = find_table_lock(net, repl->name, &ret, &ebt_mutex); 1035 if (!t) { 1036 ret = -ENOENT; 1037 goto free_iterate; 1038 } 1039 1040 /* the table doesn't like it */ 1041 if (t->check && (ret = t->check(newinfo, repl->valid_hooks))) 1042 goto free_unlock; 1043 1044 if (repl->num_counters && repl->num_counters != t->private->nentries) { 1045 BUGPRINT("Wrong nr. of counters requested\n"); 1046 ret = -EINVAL; 1047 goto free_unlock; 1048 } 1049 1050 /* we have the mutex lock, so no danger in reading this pointer */ 1051 table = t->private; 1052 /* make sure the table can only be rmmod'ed if it contains no rules */ 1053 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) { 1054 ret = -ENOENT; 1055 goto free_unlock; 1056 } else if (table->nentries && !newinfo->nentries) 1057 module_put(t->me); 1058 /* we need an atomic snapshot of the counters */ 1059 write_lock_bh(&t->lock); 1060 if (repl->num_counters) 1061 get_counters(t->private->counters, counterstmp, 1062 t->private->nentries); 1063 1064 t->private = newinfo; 1065 write_unlock_bh(&t->lock); 1066 mutex_unlock(&ebt_mutex); 1067 /* so, a user can change the chains while having messed up her counter 1068 * allocation. Only reason why this is done is because this way the lock 1069 * is held only once, while this doesn't bring the kernel into a 1070 * dangerous state. 1071 */ 1072 if (repl->num_counters && 1073 copy_to_user(repl->counters, counterstmp, 1074 repl->num_counters * sizeof(struct ebt_counter))) { 1075 /* Silent error, can't fail, new table is already in place */ 1076 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n"); 1077 } 1078 1079 /* decrease module count and free resources */ 1080 EBT_ENTRY_ITERATE(table->entries, table->entries_size, 1081 ebt_cleanup_entry, net, NULL); 1082 1083 vfree(table->entries); 1084 ebt_free_table_info(table); 1085 vfree(table); 1086 vfree(counterstmp); 1087 1088 #ifdef CONFIG_AUDIT 1089 if (audit_enabled) { 1090 audit_log(audit_context(), GFP_KERNEL, 1091 AUDIT_NETFILTER_CFG, 1092 "table=%s family=%u entries=%u", 1093 repl->name, AF_BRIDGE, repl->nentries); 1094 } 1095 #endif 1096 return ret; 1097 1098 free_unlock: 1099 mutex_unlock(&ebt_mutex); 1100 free_iterate: 1101 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 1102 ebt_cleanup_entry, net, NULL); 1103 free_counterstmp: 1104 vfree(counterstmp); 1105 /* can be initialized in translate_table() */ 1106 ebt_free_table_info(newinfo); 1107 return ret; 1108 } 1109 1110 /* replace the table */ 1111 static int do_replace(struct net *net, const void __user *user, 1112 unsigned int len) 1113 { 1114 int ret, countersize; 1115 struct ebt_table_info *newinfo; 1116 struct ebt_replace tmp; 1117 1118 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1119 return -EFAULT; 1120 1121 if (len != sizeof(tmp) + tmp.entries_size) { 1122 BUGPRINT("Wrong len argument\n"); 1123 return -EINVAL; 1124 } 1125 1126 if (tmp.entries_size == 0) { 1127 BUGPRINT("Entries_size never zero\n"); 1128 return -EINVAL; 1129 } 1130 /* overflow check */ 1131 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / 1132 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) 1133 return -ENOMEM; 1134 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) 1135 return -ENOMEM; 1136 1137 tmp.name[sizeof(tmp.name) - 1] = 0; 1138 1139 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; 1140 newinfo = vmalloc(sizeof(*newinfo) + countersize); 1141 if (!newinfo) 1142 return -ENOMEM; 1143 1144 if (countersize) 1145 memset(newinfo->counters, 0, countersize); 1146 1147 newinfo->entries = vmalloc(tmp.entries_size); 1148 if (!newinfo->entries) { 1149 ret = -ENOMEM; 1150 goto free_newinfo; 1151 } 1152 if (copy_from_user( 1153 newinfo->entries, tmp.entries, tmp.entries_size) != 0) { 1154 BUGPRINT("Couldn't copy entries from userspace\n"); 1155 ret = -EFAULT; 1156 goto free_entries; 1157 } 1158 1159 ret = do_replace_finish(net, &tmp, newinfo); 1160 if (ret == 0) 1161 return ret; 1162 free_entries: 1163 vfree(newinfo->entries); 1164 free_newinfo: 1165 vfree(newinfo); 1166 return ret; 1167 } 1168 1169 static void __ebt_unregister_table(struct net *net, struct ebt_table *table) 1170 { 1171 mutex_lock(&ebt_mutex); 1172 list_del(&table->list); 1173 mutex_unlock(&ebt_mutex); 1174 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size, 1175 ebt_cleanup_entry, net, NULL); 1176 if (table->private->nentries) 1177 module_put(table->me); 1178 vfree(table->private->entries); 1179 ebt_free_table_info(table->private); 1180 vfree(table->private); 1181 kfree(table); 1182 } 1183 1184 int ebt_register_table(struct net *net, const struct ebt_table *input_table, 1185 const struct nf_hook_ops *ops, struct ebt_table **res) 1186 { 1187 struct ebt_table_info *newinfo; 1188 struct ebt_table *t, *table; 1189 struct ebt_replace_kernel *repl; 1190 int ret, i, countersize; 1191 void *p; 1192 1193 if (input_table == NULL || (repl = input_table->table) == NULL || 1194 repl->entries == NULL || repl->entries_size == 0 || 1195 repl->counters != NULL || input_table->private != NULL) { 1196 BUGPRINT("Bad table data for ebt_register_table!!!\n"); 1197 return -EINVAL; 1198 } 1199 1200 /* Don't add one table to multiple lists. */ 1201 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL); 1202 if (!table) { 1203 ret = -ENOMEM; 1204 goto out; 1205 } 1206 1207 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids; 1208 newinfo = vmalloc(sizeof(*newinfo) + countersize); 1209 ret = -ENOMEM; 1210 if (!newinfo) 1211 goto free_table; 1212 1213 p = vmalloc(repl->entries_size); 1214 if (!p) 1215 goto free_newinfo; 1216 1217 memcpy(p, repl->entries, repl->entries_size); 1218 newinfo->entries = p; 1219 1220 newinfo->entries_size = repl->entries_size; 1221 newinfo->nentries = repl->nentries; 1222 1223 if (countersize) 1224 memset(newinfo->counters, 0, countersize); 1225 1226 /* fill in newinfo and parse the entries */ 1227 newinfo->chainstack = NULL; 1228 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1229 if ((repl->valid_hooks & (1 << i)) == 0) 1230 newinfo->hook_entry[i] = NULL; 1231 else 1232 newinfo->hook_entry[i] = p + 1233 ((char *)repl->hook_entry[i] - repl->entries); 1234 } 1235 ret = translate_table(net, repl->name, newinfo); 1236 if (ret != 0) { 1237 BUGPRINT("Translate_table failed\n"); 1238 goto free_chainstack; 1239 } 1240 1241 if (table->check && table->check(newinfo, table->valid_hooks)) { 1242 BUGPRINT("The table doesn't like its own initial data, lol\n"); 1243 ret = -EINVAL; 1244 goto free_chainstack; 1245 } 1246 1247 table->private = newinfo; 1248 rwlock_init(&table->lock); 1249 mutex_lock(&ebt_mutex); 1250 list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) { 1251 if (strcmp(t->name, table->name) == 0) { 1252 ret = -EEXIST; 1253 BUGPRINT("Table name already exists\n"); 1254 goto free_unlock; 1255 } 1256 } 1257 1258 /* Hold a reference count if the chains aren't empty */ 1259 if (newinfo->nentries && !try_module_get(table->me)) { 1260 ret = -ENOENT; 1261 goto free_unlock; 1262 } 1263 list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]); 1264 mutex_unlock(&ebt_mutex); 1265 1266 WRITE_ONCE(*res, table); 1267 1268 if (!ops) 1269 return 0; 1270 1271 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1272 if (ret) { 1273 __ebt_unregister_table(net, table); 1274 *res = NULL; 1275 } 1276 1277 return ret; 1278 free_unlock: 1279 mutex_unlock(&ebt_mutex); 1280 free_chainstack: 1281 ebt_free_table_info(newinfo); 1282 vfree(newinfo->entries); 1283 free_newinfo: 1284 vfree(newinfo); 1285 free_table: 1286 kfree(table); 1287 out: 1288 return ret; 1289 } 1290 1291 void ebt_unregister_table(struct net *net, struct ebt_table *table, 1292 const struct nf_hook_ops *ops) 1293 { 1294 if (ops) 1295 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); 1296 __ebt_unregister_table(net, table); 1297 } 1298 1299 /* userspace just supplied us with counters */ 1300 static int do_update_counters(struct net *net, const char *name, 1301 struct ebt_counter __user *counters, 1302 unsigned int num_counters, 1303 const void __user *user, unsigned int len) 1304 { 1305 int i, ret; 1306 struct ebt_counter *tmp; 1307 struct ebt_table *t; 1308 1309 if (num_counters == 0) 1310 return -EINVAL; 1311 1312 tmp = vmalloc(array_size(num_counters, sizeof(*tmp))); 1313 if (!tmp) 1314 return -ENOMEM; 1315 1316 t = find_table_lock(net, name, &ret, &ebt_mutex); 1317 if (!t) 1318 goto free_tmp; 1319 1320 if (num_counters != t->private->nentries) { 1321 BUGPRINT("Wrong nr of counters\n"); 1322 ret = -EINVAL; 1323 goto unlock_mutex; 1324 } 1325 1326 if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) { 1327 ret = -EFAULT; 1328 goto unlock_mutex; 1329 } 1330 1331 /* we want an atomic add of the counters */ 1332 write_lock_bh(&t->lock); 1333 1334 /* we add to the counters of the first cpu */ 1335 for (i = 0; i < num_counters; i++) 1336 ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt); 1337 1338 write_unlock_bh(&t->lock); 1339 ret = 0; 1340 unlock_mutex: 1341 mutex_unlock(&ebt_mutex); 1342 free_tmp: 1343 vfree(tmp); 1344 return ret; 1345 } 1346 1347 static int update_counters(struct net *net, const void __user *user, 1348 unsigned int len) 1349 { 1350 struct ebt_replace hlp; 1351 1352 if (copy_from_user(&hlp, user, sizeof(hlp))) 1353 return -EFAULT; 1354 1355 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 1356 return -EINVAL; 1357 1358 return do_update_counters(net, hlp.name, hlp.counters, 1359 hlp.num_counters, user, len); 1360 } 1361 1362 static inline int ebt_obj_to_user(char __user *um, const char *_name, 1363 const char *data, int entrysize, 1364 int usersize, int datasize, u8 revision) 1365 { 1366 char name[EBT_EXTENSION_MAXNAMELEN] = {0}; 1367 1368 /* ebtables expects 31 bytes long names but xt_match names are 29 bytes 1369 * long. Copy 29 bytes and fill remaining bytes with zeroes. 1370 */ 1371 strlcpy(name, _name, sizeof(name)); 1372 if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) || 1373 put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) || 1374 put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) || 1375 xt_data_to_user(um + entrysize, data, usersize, datasize, 1376 XT_ALIGN(datasize))) 1377 return -EFAULT; 1378 1379 return 0; 1380 } 1381 1382 static inline int ebt_match_to_user(const struct ebt_entry_match *m, 1383 const char *base, char __user *ubase) 1384 { 1385 return ebt_obj_to_user(ubase + ((char *)m - base), 1386 m->u.match->name, m->data, sizeof(*m), 1387 m->u.match->usersize, m->match_size, 1388 m->u.match->revision); 1389 } 1390 1391 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w, 1392 const char *base, char __user *ubase) 1393 { 1394 return ebt_obj_to_user(ubase + ((char *)w - base), 1395 w->u.watcher->name, w->data, sizeof(*w), 1396 w->u.watcher->usersize, w->watcher_size, 1397 w->u.watcher->revision); 1398 } 1399 1400 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base, 1401 char __user *ubase) 1402 { 1403 int ret; 1404 char __user *hlp; 1405 const struct ebt_entry_target *t; 1406 1407 if (e->bitmask == 0) { 1408 /* special case !EBT_ENTRY_OR_ENTRIES */ 1409 if (copy_to_user(ubase + ((char *)e - base), e, 1410 sizeof(struct ebt_entries))) 1411 return -EFAULT; 1412 return 0; 1413 } 1414 1415 if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e))) 1416 return -EFAULT; 1417 1418 hlp = ubase + (((char *)e + e->target_offset) - base); 1419 t = ebt_get_target_c(e); 1420 1421 ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase); 1422 if (ret != 0) 1423 return ret; 1424 ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase); 1425 if (ret != 0) 1426 return ret; 1427 ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t), 1428 t->u.target->usersize, t->target_size, 1429 t->u.target->revision); 1430 if (ret != 0) 1431 return ret; 1432 1433 return 0; 1434 } 1435 1436 static int copy_counters_to_user(struct ebt_table *t, 1437 const struct ebt_counter *oldcounters, 1438 void __user *user, unsigned int num_counters, 1439 unsigned int nentries) 1440 { 1441 struct ebt_counter *counterstmp; 1442 int ret = 0; 1443 1444 /* userspace might not need the counters */ 1445 if (num_counters == 0) 1446 return 0; 1447 1448 if (num_counters != nentries) { 1449 BUGPRINT("Num_counters wrong\n"); 1450 return -EINVAL; 1451 } 1452 1453 counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp))); 1454 if (!counterstmp) 1455 return -ENOMEM; 1456 1457 write_lock_bh(&t->lock); 1458 get_counters(oldcounters, counterstmp, nentries); 1459 write_unlock_bh(&t->lock); 1460 1461 if (copy_to_user(user, counterstmp, 1462 nentries * sizeof(struct ebt_counter))) 1463 ret = -EFAULT; 1464 vfree(counterstmp); 1465 return ret; 1466 } 1467 1468 /* called with ebt_mutex locked */ 1469 static int copy_everything_to_user(struct ebt_table *t, void __user *user, 1470 const int *len, int cmd) 1471 { 1472 struct ebt_replace tmp; 1473 const struct ebt_counter *oldcounters; 1474 unsigned int entries_size, nentries; 1475 int ret; 1476 char *entries; 1477 1478 if (cmd == EBT_SO_GET_ENTRIES) { 1479 entries_size = t->private->entries_size; 1480 nentries = t->private->nentries; 1481 entries = t->private->entries; 1482 oldcounters = t->private->counters; 1483 } else { 1484 entries_size = t->table->entries_size; 1485 nentries = t->table->nentries; 1486 entries = t->table->entries; 1487 oldcounters = t->table->counters; 1488 } 1489 1490 if (copy_from_user(&tmp, user, sizeof(tmp))) 1491 return -EFAULT; 1492 1493 if (*len != sizeof(struct ebt_replace) + entries_size + 1494 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0)) 1495 return -EINVAL; 1496 1497 if (tmp.nentries != nentries) { 1498 BUGPRINT("Nentries wrong\n"); 1499 return -EINVAL; 1500 } 1501 1502 if (tmp.entries_size != entries_size) { 1503 BUGPRINT("Wrong size\n"); 1504 return -EINVAL; 1505 } 1506 1507 ret = copy_counters_to_user(t, oldcounters, tmp.counters, 1508 tmp.num_counters, nentries); 1509 if (ret) 1510 return ret; 1511 1512 /* set the match/watcher/target names right */ 1513 return EBT_ENTRY_ITERATE(entries, entries_size, 1514 ebt_entry_to_user, entries, tmp.entries); 1515 } 1516 1517 static int do_ebt_set_ctl(struct sock *sk, 1518 int cmd, void __user *user, unsigned int len) 1519 { 1520 int ret; 1521 struct net *net = sock_net(sk); 1522 1523 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1524 return -EPERM; 1525 1526 switch (cmd) { 1527 case EBT_SO_SET_ENTRIES: 1528 ret = do_replace(net, user, len); 1529 break; 1530 case EBT_SO_SET_COUNTERS: 1531 ret = update_counters(net, user, len); 1532 break; 1533 default: 1534 ret = -EINVAL; 1535 } 1536 return ret; 1537 } 1538 1539 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1540 { 1541 int ret; 1542 struct ebt_replace tmp; 1543 struct ebt_table *t; 1544 struct net *net = sock_net(sk); 1545 1546 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1547 return -EPERM; 1548 1549 if (copy_from_user(&tmp, user, sizeof(tmp))) 1550 return -EFAULT; 1551 1552 tmp.name[sizeof(tmp.name) - 1] = '\0'; 1553 1554 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 1555 if (!t) 1556 return ret; 1557 1558 switch (cmd) { 1559 case EBT_SO_GET_INFO: 1560 case EBT_SO_GET_INIT_INFO: 1561 if (*len != sizeof(struct ebt_replace)) { 1562 ret = -EINVAL; 1563 mutex_unlock(&ebt_mutex); 1564 break; 1565 } 1566 if (cmd == EBT_SO_GET_INFO) { 1567 tmp.nentries = t->private->nentries; 1568 tmp.entries_size = t->private->entries_size; 1569 tmp.valid_hooks = t->valid_hooks; 1570 } else { 1571 tmp.nentries = t->table->nentries; 1572 tmp.entries_size = t->table->entries_size; 1573 tmp.valid_hooks = t->table->valid_hooks; 1574 } 1575 mutex_unlock(&ebt_mutex); 1576 if (copy_to_user(user, &tmp, *len) != 0) { 1577 BUGPRINT("c2u Didn't work\n"); 1578 ret = -EFAULT; 1579 break; 1580 } 1581 ret = 0; 1582 break; 1583 1584 case EBT_SO_GET_ENTRIES: 1585 case EBT_SO_GET_INIT_ENTRIES: 1586 ret = copy_everything_to_user(t, user, len, cmd); 1587 mutex_unlock(&ebt_mutex); 1588 break; 1589 1590 default: 1591 mutex_unlock(&ebt_mutex); 1592 ret = -EINVAL; 1593 } 1594 1595 return ret; 1596 } 1597 1598 #ifdef CONFIG_COMPAT 1599 /* 32 bit-userspace compatibility definitions. */ 1600 struct compat_ebt_replace { 1601 char name[EBT_TABLE_MAXNAMELEN]; 1602 compat_uint_t valid_hooks; 1603 compat_uint_t nentries; 1604 compat_uint_t entries_size; 1605 /* start of the chains */ 1606 compat_uptr_t hook_entry[NF_BR_NUMHOOKS]; 1607 /* nr of counters userspace expects back */ 1608 compat_uint_t num_counters; 1609 /* where the kernel will put the old counters. */ 1610 compat_uptr_t counters; 1611 compat_uptr_t entries; 1612 }; 1613 1614 /* struct ebt_entry_match, _target and _watcher have same layout */ 1615 struct compat_ebt_entry_mwt { 1616 union { 1617 struct { 1618 char name[EBT_EXTENSION_MAXNAMELEN]; 1619 u8 revision; 1620 }; 1621 compat_uptr_t ptr; 1622 } u; 1623 compat_uint_t match_size; 1624 compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace)))); 1625 }; 1626 1627 /* account for possible padding between match_size and ->data */ 1628 static int ebt_compat_entry_padsize(void) 1629 { 1630 BUILD_BUG_ON(sizeof(struct ebt_entry_match) < 1631 sizeof(struct compat_ebt_entry_mwt)); 1632 return (int) sizeof(struct ebt_entry_match) - 1633 sizeof(struct compat_ebt_entry_mwt); 1634 } 1635 1636 static int ebt_compat_match_offset(const struct xt_match *match, 1637 unsigned int userlen) 1638 { 1639 /* ebt_among needs special handling. The kernel .matchsize is 1640 * set to -1 at registration time; at runtime an EBT_ALIGN()ed 1641 * value is expected. 1642 * Example: userspace sends 4500, ebt_among.c wants 4504. 1643 */ 1644 if (unlikely(match->matchsize == -1)) 1645 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen); 1646 return xt_compat_match_offset(match); 1647 } 1648 1649 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr, 1650 unsigned int *size) 1651 { 1652 const struct xt_match *match = m->u.match; 1653 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1654 int off = ebt_compat_match_offset(match, m->match_size); 1655 compat_uint_t msize = m->match_size - off; 1656 1657 if (WARN_ON(off >= m->match_size)) 1658 return -EINVAL; 1659 1660 if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) || 1661 put_user(match->revision, &cm->u.revision) || 1662 put_user(msize, &cm->match_size)) 1663 return -EFAULT; 1664 1665 if (match->compat_to_user) { 1666 if (match->compat_to_user(cm->data, m->data)) 1667 return -EFAULT; 1668 } else { 1669 if (xt_data_to_user(cm->data, m->data, match->usersize, msize, 1670 COMPAT_XT_ALIGN(msize))) 1671 return -EFAULT; 1672 } 1673 1674 *size -= ebt_compat_entry_padsize() + off; 1675 *dstptr = cm->data; 1676 *dstptr += msize; 1677 return 0; 1678 } 1679 1680 static int compat_target_to_user(struct ebt_entry_target *t, 1681 void __user **dstptr, 1682 unsigned int *size) 1683 { 1684 const struct xt_target *target = t->u.target; 1685 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1686 int off = xt_compat_target_offset(target); 1687 compat_uint_t tsize = t->target_size - off; 1688 1689 if (WARN_ON(off >= t->target_size)) 1690 return -EINVAL; 1691 1692 if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) || 1693 put_user(target->revision, &cm->u.revision) || 1694 put_user(tsize, &cm->match_size)) 1695 return -EFAULT; 1696 1697 if (target->compat_to_user) { 1698 if (target->compat_to_user(cm->data, t->data)) 1699 return -EFAULT; 1700 } else { 1701 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize, 1702 COMPAT_XT_ALIGN(tsize))) 1703 return -EFAULT; 1704 } 1705 1706 *size -= ebt_compat_entry_padsize() + off; 1707 *dstptr = cm->data; 1708 *dstptr += tsize; 1709 return 0; 1710 } 1711 1712 static int compat_watcher_to_user(struct ebt_entry_watcher *w, 1713 void __user **dstptr, 1714 unsigned int *size) 1715 { 1716 return compat_target_to_user((struct ebt_entry_target *)w, 1717 dstptr, size); 1718 } 1719 1720 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr, 1721 unsigned int *size) 1722 { 1723 struct ebt_entry_target *t; 1724 struct ebt_entry __user *ce; 1725 u32 watchers_offset, target_offset, next_offset; 1726 compat_uint_t origsize; 1727 int ret; 1728 1729 if (e->bitmask == 0) { 1730 if (*size < sizeof(struct ebt_entries)) 1731 return -EINVAL; 1732 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries))) 1733 return -EFAULT; 1734 1735 *dstptr += sizeof(struct ebt_entries); 1736 *size -= sizeof(struct ebt_entries); 1737 return 0; 1738 } 1739 1740 if (*size < sizeof(*ce)) 1741 return -EINVAL; 1742 1743 ce = *dstptr; 1744 if (copy_to_user(ce, e, sizeof(*ce))) 1745 return -EFAULT; 1746 1747 origsize = *size; 1748 *dstptr += sizeof(*ce); 1749 1750 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size); 1751 if (ret) 1752 return ret; 1753 watchers_offset = e->watchers_offset - (origsize - *size); 1754 1755 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size); 1756 if (ret) 1757 return ret; 1758 target_offset = e->target_offset - (origsize - *size); 1759 1760 t = ebt_get_target(e); 1761 1762 ret = compat_target_to_user(t, dstptr, size); 1763 if (ret) 1764 return ret; 1765 next_offset = e->next_offset - (origsize - *size); 1766 1767 if (put_user(watchers_offset, &ce->watchers_offset) || 1768 put_user(target_offset, &ce->target_offset) || 1769 put_user(next_offset, &ce->next_offset)) 1770 return -EFAULT; 1771 1772 *size -= sizeof(*ce); 1773 return 0; 1774 } 1775 1776 static int compat_calc_match(struct ebt_entry_match *m, int *off) 1777 { 1778 *off += ebt_compat_match_offset(m->u.match, m->match_size); 1779 *off += ebt_compat_entry_padsize(); 1780 return 0; 1781 } 1782 1783 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off) 1784 { 1785 *off += xt_compat_target_offset(w->u.watcher); 1786 *off += ebt_compat_entry_padsize(); 1787 return 0; 1788 } 1789 1790 static int compat_calc_entry(const struct ebt_entry *e, 1791 const struct ebt_table_info *info, 1792 const void *base, 1793 struct compat_ebt_replace *newinfo) 1794 { 1795 const struct ebt_entry_target *t; 1796 unsigned int entry_offset; 1797 int off, ret, i; 1798 1799 if (e->bitmask == 0) 1800 return 0; 1801 1802 off = 0; 1803 entry_offset = (void *)e - base; 1804 1805 EBT_MATCH_ITERATE(e, compat_calc_match, &off); 1806 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off); 1807 1808 t = ebt_get_target_c(e); 1809 1810 off += xt_compat_target_offset(t->u.target); 1811 off += ebt_compat_entry_padsize(); 1812 1813 newinfo->entries_size -= off; 1814 1815 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off); 1816 if (ret) 1817 return ret; 1818 1819 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1820 const void *hookptr = info->hook_entry[i]; 1821 if (info->hook_entry[i] && 1822 (e < (struct ebt_entry *)(base - hookptr))) { 1823 newinfo->hook_entry[i] -= off; 1824 pr_debug("0x%08X -> 0x%08X\n", 1825 newinfo->hook_entry[i] + off, 1826 newinfo->hook_entry[i]); 1827 } 1828 } 1829 1830 return 0; 1831 } 1832 1833 1834 static int compat_table_info(const struct ebt_table_info *info, 1835 struct compat_ebt_replace *newinfo) 1836 { 1837 unsigned int size = info->entries_size; 1838 const void *entries = info->entries; 1839 1840 newinfo->entries_size = size; 1841 if (info->nentries) { 1842 int ret = xt_compat_init_offsets(NFPROTO_BRIDGE, 1843 info->nentries); 1844 if (ret) 1845 return ret; 1846 } 1847 1848 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, 1849 entries, newinfo); 1850 } 1851 1852 static int compat_copy_everything_to_user(struct ebt_table *t, 1853 void __user *user, int *len, int cmd) 1854 { 1855 struct compat_ebt_replace repl, tmp; 1856 struct ebt_counter *oldcounters; 1857 struct ebt_table_info tinfo; 1858 int ret; 1859 void __user *pos; 1860 1861 memset(&tinfo, 0, sizeof(tinfo)); 1862 1863 if (cmd == EBT_SO_GET_ENTRIES) { 1864 tinfo.entries_size = t->private->entries_size; 1865 tinfo.nentries = t->private->nentries; 1866 tinfo.entries = t->private->entries; 1867 oldcounters = t->private->counters; 1868 } else { 1869 tinfo.entries_size = t->table->entries_size; 1870 tinfo.nentries = t->table->nentries; 1871 tinfo.entries = t->table->entries; 1872 oldcounters = t->table->counters; 1873 } 1874 1875 if (copy_from_user(&tmp, user, sizeof(tmp))) 1876 return -EFAULT; 1877 1878 if (tmp.nentries != tinfo.nentries || 1879 (tmp.num_counters && tmp.num_counters != tinfo.nentries)) 1880 return -EINVAL; 1881 1882 memcpy(&repl, &tmp, sizeof(repl)); 1883 if (cmd == EBT_SO_GET_ENTRIES) 1884 ret = compat_table_info(t->private, &repl); 1885 else 1886 ret = compat_table_info(&tinfo, &repl); 1887 if (ret) 1888 return ret; 1889 1890 if (*len != sizeof(tmp) + repl.entries_size + 1891 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) { 1892 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n", 1893 *len, tinfo.entries_size, repl.entries_size); 1894 return -EINVAL; 1895 } 1896 1897 /* userspace might not need the counters */ 1898 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters), 1899 tmp.num_counters, tinfo.nentries); 1900 if (ret) 1901 return ret; 1902 1903 pos = compat_ptr(tmp.entries); 1904 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size, 1905 compat_copy_entry_to_user, &pos, &tmp.entries_size); 1906 } 1907 1908 struct ebt_entries_buf_state { 1909 char *buf_kern_start; /* kernel buffer to copy (translated) data to */ 1910 u32 buf_kern_len; /* total size of kernel buffer */ 1911 u32 buf_kern_offset; /* amount of data copied so far */ 1912 u32 buf_user_offset; /* read position in userspace buffer */ 1913 }; 1914 1915 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz) 1916 { 1917 state->buf_kern_offset += sz; 1918 return state->buf_kern_offset >= sz ? 0 : -EINVAL; 1919 } 1920 1921 static int ebt_buf_add(struct ebt_entries_buf_state *state, 1922 void *data, unsigned int sz) 1923 { 1924 if (state->buf_kern_start == NULL) 1925 goto count_only; 1926 1927 if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len)) 1928 return -EINVAL; 1929 1930 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz); 1931 1932 count_only: 1933 state->buf_user_offset += sz; 1934 return ebt_buf_count(state, sz); 1935 } 1936 1937 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz) 1938 { 1939 char *b = state->buf_kern_start; 1940 1941 if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len)) 1942 return -EINVAL; 1943 1944 if (b != NULL && sz > 0) 1945 memset(b + state->buf_kern_offset, 0, sz); 1946 /* do not adjust ->buf_user_offset here, we added kernel-side padding */ 1947 return ebt_buf_count(state, sz); 1948 } 1949 1950 enum compat_mwt { 1951 EBT_COMPAT_MATCH, 1952 EBT_COMPAT_WATCHER, 1953 EBT_COMPAT_TARGET, 1954 }; 1955 1956 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt, 1957 enum compat_mwt compat_mwt, 1958 struct ebt_entries_buf_state *state, 1959 const unsigned char *base) 1960 { 1961 char name[EBT_EXTENSION_MAXNAMELEN]; 1962 struct xt_match *match; 1963 struct xt_target *wt; 1964 void *dst = NULL; 1965 int off, pad = 0; 1966 unsigned int size_kern, match_size = mwt->match_size; 1967 1968 if (strscpy(name, mwt->u.name, sizeof(name)) < 0) 1969 return -EINVAL; 1970 1971 if (state->buf_kern_start) 1972 dst = state->buf_kern_start + state->buf_kern_offset; 1973 1974 switch (compat_mwt) { 1975 case EBT_COMPAT_MATCH: 1976 match = xt_request_find_match(NFPROTO_BRIDGE, name, 1977 mwt->u.revision); 1978 if (IS_ERR(match)) 1979 return PTR_ERR(match); 1980 1981 off = ebt_compat_match_offset(match, match_size); 1982 if (dst) { 1983 if (match->compat_from_user) 1984 match->compat_from_user(dst, mwt->data); 1985 else 1986 memcpy(dst, mwt->data, match_size); 1987 } 1988 1989 size_kern = match->matchsize; 1990 if (unlikely(size_kern == -1)) 1991 size_kern = match_size; 1992 module_put(match->me); 1993 break; 1994 case EBT_COMPAT_WATCHER: /* fallthrough */ 1995 case EBT_COMPAT_TARGET: 1996 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 1997 mwt->u.revision); 1998 if (IS_ERR(wt)) 1999 return PTR_ERR(wt); 2000 off = xt_compat_target_offset(wt); 2001 2002 if (dst) { 2003 if (wt->compat_from_user) 2004 wt->compat_from_user(dst, mwt->data); 2005 else 2006 memcpy(dst, mwt->data, match_size); 2007 } 2008 2009 size_kern = wt->targetsize; 2010 module_put(wt->me); 2011 break; 2012 2013 default: 2014 return -EINVAL; 2015 } 2016 2017 state->buf_kern_offset += match_size + off; 2018 state->buf_user_offset += match_size; 2019 pad = XT_ALIGN(size_kern) - size_kern; 2020 2021 if (pad > 0 && dst) { 2022 if (WARN_ON(state->buf_kern_len <= pad)) 2023 return -EINVAL; 2024 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad)) 2025 return -EINVAL; 2026 memset(dst + size_kern, 0, pad); 2027 } 2028 return off + match_size; 2029 } 2030 2031 /* return size of all matches, watchers or target, including necessary 2032 * alignment and padding. 2033 */ 2034 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32, 2035 unsigned int size_left, enum compat_mwt type, 2036 struct ebt_entries_buf_state *state, const void *base) 2037 { 2038 int growth = 0; 2039 char *buf; 2040 2041 if (size_left == 0) 2042 return 0; 2043 2044 buf = (char *) match32; 2045 2046 while (size_left >= sizeof(*match32)) { 2047 struct ebt_entry_match *match_kern; 2048 int ret; 2049 2050 match_kern = (struct ebt_entry_match *) state->buf_kern_start; 2051 if (match_kern) { 2052 char *tmp; 2053 tmp = state->buf_kern_start + state->buf_kern_offset; 2054 match_kern = (struct ebt_entry_match *) tmp; 2055 } 2056 ret = ebt_buf_add(state, buf, sizeof(*match32)); 2057 if (ret < 0) 2058 return ret; 2059 size_left -= sizeof(*match32); 2060 2061 /* add padding before match->data (if any) */ 2062 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize()); 2063 if (ret < 0) 2064 return ret; 2065 2066 if (match32->match_size > size_left) 2067 return -EINVAL; 2068 2069 size_left -= match32->match_size; 2070 2071 ret = compat_mtw_from_user(match32, type, state, base); 2072 if (ret < 0) 2073 return ret; 2074 2075 if (WARN_ON(ret < match32->match_size)) 2076 return -EINVAL; 2077 growth += ret - match32->match_size; 2078 growth += ebt_compat_entry_padsize(); 2079 2080 buf += sizeof(*match32); 2081 buf += match32->match_size; 2082 2083 if (match_kern) 2084 match_kern->match_size = ret; 2085 2086 if (WARN_ON(type == EBT_COMPAT_TARGET && size_left)) 2087 return -EINVAL; 2088 2089 match32 = (struct compat_ebt_entry_mwt *) buf; 2090 } 2091 2092 return growth; 2093 } 2094 2095 /* called for all ebt_entry structures. */ 2096 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, 2097 unsigned int *total, 2098 struct ebt_entries_buf_state *state) 2099 { 2100 unsigned int i, j, startoff, new_offset = 0; 2101 /* stores match/watchers/targets & offset of next struct ebt_entry: */ 2102 unsigned int offsets[4]; 2103 unsigned int *offsets_update = NULL; 2104 int ret; 2105 char *buf_start; 2106 2107 if (*total < sizeof(struct ebt_entries)) 2108 return -EINVAL; 2109 2110 if (!entry->bitmask) { 2111 *total -= sizeof(struct ebt_entries); 2112 return ebt_buf_add(state, entry, sizeof(struct ebt_entries)); 2113 } 2114 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry)) 2115 return -EINVAL; 2116 2117 startoff = state->buf_user_offset; 2118 /* pull in most part of ebt_entry, it does not need to be changed. */ 2119 ret = ebt_buf_add(state, entry, 2120 offsetof(struct ebt_entry, watchers_offset)); 2121 if (ret < 0) 2122 return ret; 2123 2124 offsets[0] = sizeof(struct ebt_entry); /* matches come first */ 2125 memcpy(&offsets[1], &entry->watchers_offset, 2126 sizeof(offsets) - sizeof(offsets[0])); 2127 2128 if (state->buf_kern_start) { 2129 buf_start = state->buf_kern_start + state->buf_kern_offset; 2130 offsets_update = (unsigned int *) buf_start; 2131 } 2132 ret = ebt_buf_add(state, &offsets[1], 2133 sizeof(offsets) - sizeof(offsets[0])); 2134 if (ret < 0) 2135 return ret; 2136 buf_start = (char *) entry; 2137 /* 0: matches offset, always follows ebt_entry. 2138 * 1: watchers offset, from ebt_entry structure 2139 * 2: target offset, from ebt_entry structure 2140 * 3: next ebt_entry offset, from ebt_entry structure 2141 * 2142 * offsets are relative to beginning of struct ebt_entry (i.e., 0). 2143 */ 2144 for (i = 0; i < 4 ; ++i) { 2145 if (offsets[i] > *total) 2146 return -EINVAL; 2147 2148 if (i < 3 && offsets[i] == *total) 2149 return -EINVAL; 2150 2151 if (i == 0) 2152 continue; 2153 if (offsets[i-1] > offsets[i]) 2154 return -EINVAL; 2155 } 2156 2157 for (i = 0, j = 1 ; j < 4 ; j++, i++) { 2158 struct compat_ebt_entry_mwt *match32; 2159 unsigned int size; 2160 char *buf = buf_start + offsets[i]; 2161 2162 if (offsets[i] > offsets[j]) 2163 return -EINVAL; 2164 2165 match32 = (struct compat_ebt_entry_mwt *) buf; 2166 size = offsets[j] - offsets[i]; 2167 ret = ebt_size_mwt(match32, size, i, state, base); 2168 if (ret < 0) 2169 return ret; 2170 new_offset += ret; 2171 if (offsets_update && new_offset) { 2172 pr_debug("change offset %d to %d\n", 2173 offsets_update[i], offsets[j] + new_offset); 2174 offsets_update[i] = offsets[j] + new_offset; 2175 } 2176 } 2177 2178 if (state->buf_kern_start == NULL) { 2179 unsigned int offset = buf_start - (char *) base; 2180 2181 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset); 2182 if (ret < 0) 2183 return ret; 2184 } 2185 2186 startoff = state->buf_user_offset - startoff; 2187 2188 if (WARN_ON(*total < startoff)) 2189 return -EINVAL; 2190 *total -= startoff; 2191 return 0; 2192 } 2193 2194 /* repl->entries_size is the size of the ebt_entry blob in userspace. 2195 * It might need more memory when copied to a 64 bit kernel in case 2196 * userspace is 32-bit. So, first task: find out how much memory is needed. 2197 * 2198 * Called before validation is performed. 2199 */ 2200 static int compat_copy_entries(unsigned char *data, unsigned int size_user, 2201 struct ebt_entries_buf_state *state) 2202 { 2203 unsigned int size_remaining = size_user; 2204 int ret; 2205 2206 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data, 2207 &size_remaining, state); 2208 if (ret < 0) 2209 return ret; 2210 2211 WARN_ON(size_remaining); 2212 return state->buf_kern_offset; 2213 } 2214 2215 2216 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, 2217 void __user *user, unsigned int len) 2218 { 2219 struct compat_ebt_replace tmp; 2220 int i; 2221 2222 if (len < sizeof(tmp)) 2223 return -EINVAL; 2224 2225 if (copy_from_user(&tmp, user, sizeof(tmp))) 2226 return -EFAULT; 2227 2228 if (len != sizeof(tmp) + tmp.entries_size) 2229 return -EINVAL; 2230 2231 if (tmp.entries_size == 0) 2232 return -EINVAL; 2233 2234 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / 2235 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) 2236 return -ENOMEM; 2237 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) 2238 return -ENOMEM; 2239 2240 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry)); 2241 2242 /* starting with hook_entry, 32 vs. 64 bit structures are different */ 2243 for (i = 0; i < NF_BR_NUMHOOKS; i++) 2244 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]); 2245 2246 repl->num_counters = tmp.num_counters; 2247 repl->counters = compat_ptr(tmp.counters); 2248 repl->entries = compat_ptr(tmp.entries); 2249 return 0; 2250 } 2251 2252 static int compat_do_replace(struct net *net, void __user *user, 2253 unsigned int len) 2254 { 2255 int ret, i, countersize, size64; 2256 struct ebt_table_info *newinfo; 2257 struct ebt_replace tmp; 2258 struct ebt_entries_buf_state state; 2259 void *entries_tmp; 2260 2261 ret = compat_copy_ebt_replace_from_user(&tmp, user, len); 2262 if (ret) { 2263 /* try real handler in case userland supplied needed padding */ 2264 if (ret == -EINVAL && do_replace(net, user, len) == 0) 2265 ret = 0; 2266 return ret; 2267 } 2268 2269 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; 2270 newinfo = vmalloc(sizeof(*newinfo) + countersize); 2271 if (!newinfo) 2272 return -ENOMEM; 2273 2274 if (countersize) 2275 memset(newinfo->counters, 0, countersize); 2276 2277 memset(&state, 0, sizeof(state)); 2278 2279 newinfo->entries = vmalloc(tmp.entries_size); 2280 if (!newinfo->entries) { 2281 ret = -ENOMEM; 2282 goto free_newinfo; 2283 } 2284 if (copy_from_user( 2285 newinfo->entries, tmp.entries, tmp.entries_size) != 0) { 2286 ret = -EFAULT; 2287 goto free_entries; 2288 } 2289 2290 entries_tmp = newinfo->entries; 2291 2292 xt_compat_lock(NFPROTO_BRIDGE); 2293 2294 ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries); 2295 if (ret < 0) 2296 goto out_unlock; 2297 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2298 if (ret < 0) 2299 goto out_unlock; 2300 2301 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n", 2302 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset, 2303 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size)); 2304 2305 size64 = ret; 2306 newinfo->entries = vmalloc(size64); 2307 if (!newinfo->entries) { 2308 vfree(entries_tmp); 2309 ret = -ENOMEM; 2310 goto out_unlock; 2311 } 2312 2313 memset(&state, 0, sizeof(state)); 2314 state.buf_kern_start = newinfo->entries; 2315 state.buf_kern_len = size64; 2316 2317 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2318 if (WARN_ON(ret < 0)) 2319 goto out_unlock; 2320 2321 vfree(entries_tmp); 2322 tmp.entries_size = size64; 2323 2324 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 2325 char __user *usrptr; 2326 if (tmp.hook_entry[i]) { 2327 unsigned int delta; 2328 usrptr = (char __user *) tmp.hook_entry[i]; 2329 delta = usrptr - tmp.entries; 2330 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta); 2331 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr; 2332 } 2333 } 2334 2335 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2336 xt_compat_unlock(NFPROTO_BRIDGE); 2337 2338 ret = do_replace_finish(net, &tmp, newinfo); 2339 if (ret == 0) 2340 return ret; 2341 free_entries: 2342 vfree(newinfo->entries); 2343 free_newinfo: 2344 vfree(newinfo); 2345 return ret; 2346 out_unlock: 2347 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2348 xt_compat_unlock(NFPROTO_BRIDGE); 2349 goto free_entries; 2350 } 2351 2352 static int compat_update_counters(struct net *net, void __user *user, 2353 unsigned int len) 2354 { 2355 struct compat_ebt_replace hlp; 2356 2357 if (copy_from_user(&hlp, user, sizeof(hlp))) 2358 return -EFAULT; 2359 2360 /* try real handler in case userland supplied needed padding */ 2361 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 2362 return update_counters(net, user, len); 2363 2364 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters), 2365 hlp.num_counters, user, len); 2366 } 2367 2368 static int compat_do_ebt_set_ctl(struct sock *sk, 2369 int cmd, void __user *user, unsigned int len) 2370 { 2371 int ret; 2372 struct net *net = sock_net(sk); 2373 2374 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2375 return -EPERM; 2376 2377 switch (cmd) { 2378 case EBT_SO_SET_ENTRIES: 2379 ret = compat_do_replace(net, user, len); 2380 break; 2381 case EBT_SO_SET_COUNTERS: 2382 ret = compat_update_counters(net, user, len); 2383 break; 2384 default: 2385 ret = -EINVAL; 2386 } 2387 return ret; 2388 } 2389 2390 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd, 2391 void __user *user, int *len) 2392 { 2393 int ret; 2394 struct compat_ebt_replace tmp; 2395 struct ebt_table *t; 2396 struct net *net = sock_net(sk); 2397 2398 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2399 return -EPERM; 2400 2401 /* try real handler in case userland supplied needed padding */ 2402 if ((cmd == EBT_SO_GET_INFO || 2403 cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp)) 2404 return do_ebt_get_ctl(sk, cmd, user, len); 2405 2406 if (copy_from_user(&tmp, user, sizeof(tmp))) 2407 return -EFAULT; 2408 2409 tmp.name[sizeof(tmp.name) - 1] = '\0'; 2410 2411 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 2412 if (!t) 2413 return ret; 2414 2415 xt_compat_lock(NFPROTO_BRIDGE); 2416 switch (cmd) { 2417 case EBT_SO_GET_INFO: 2418 tmp.nentries = t->private->nentries; 2419 ret = compat_table_info(t->private, &tmp); 2420 if (ret) 2421 goto out; 2422 tmp.valid_hooks = t->valid_hooks; 2423 2424 if (copy_to_user(user, &tmp, *len) != 0) { 2425 ret = -EFAULT; 2426 break; 2427 } 2428 ret = 0; 2429 break; 2430 case EBT_SO_GET_INIT_INFO: 2431 tmp.nentries = t->table->nentries; 2432 tmp.entries_size = t->table->entries_size; 2433 tmp.valid_hooks = t->table->valid_hooks; 2434 2435 if (copy_to_user(user, &tmp, *len) != 0) { 2436 ret = -EFAULT; 2437 break; 2438 } 2439 ret = 0; 2440 break; 2441 case EBT_SO_GET_ENTRIES: 2442 case EBT_SO_GET_INIT_ENTRIES: 2443 /* try real handler first in case of userland-side padding. 2444 * in case we are dealing with an 'ordinary' 32 bit binary 2445 * without 64bit compatibility padding, this will fail right 2446 * after copy_from_user when the *len argument is validated. 2447 * 2448 * the compat_ variant needs to do one pass over the kernel 2449 * data set to adjust for size differences before it the check. 2450 */ 2451 if (copy_everything_to_user(t, user, len, cmd) == 0) 2452 ret = 0; 2453 else 2454 ret = compat_copy_everything_to_user(t, user, len, cmd); 2455 break; 2456 default: 2457 ret = -EINVAL; 2458 } 2459 out: 2460 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2461 xt_compat_unlock(NFPROTO_BRIDGE); 2462 mutex_unlock(&ebt_mutex); 2463 return ret; 2464 } 2465 #endif 2466 2467 static struct nf_sockopt_ops ebt_sockopts = { 2468 .pf = PF_INET, 2469 .set_optmin = EBT_BASE_CTL, 2470 .set_optmax = EBT_SO_SET_MAX + 1, 2471 .set = do_ebt_set_ctl, 2472 #ifdef CONFIG_COMPAT 2473 .compat_set = compat_do_ebt_set_ctl, 2474 #endif 2475 .get_optmin = EBT_BASE_CTL, 2476 .get_optmax = EBT_SO_GET_MAX + 1, 2477 .get = do_ebt_get_ctl, 2478 #ifdef CONFIG_COMPAT 2479 .compat_get = compat_do_ebt_get_ctl, 2480 #endif 2481 .owner = THIS_MODULE, 2482 }; 2483 2484 static int __init ebtables_init(void) 2485 { 2486 int ret; 2487 2488 ret = xt_register_target(&ebt_standard_target); 2489 if (ret < 0) 2490 return ret; 2491 ret = nf_register_sockopt(&ebt_sockopts); 2492 if (ret < 0) { 2493 xt_unregister_target(&ebt_standard_target); 2494 return ret; 2495 } 2496 2497 return 0; 2498 } 2499 2500 static void __exit ebtables_fini(void) 2501 { 2502 nf_unregister_sockopt(&ebt_sockopts); 2503 xt_unregister_target(&ebt_standard_target); 2504 } 2505 2506 EXPORT_SYMBOL(ebt_register_table); 2507 EXPORT_SYMBOL(ebt_unregister_table); 2508 EXPORT_SYMBOL(ebt_do_table); 2509 module_init(ebtables_init); 2510 module_exit(ebtables_fini); 2511 MODULE_LICENSE("GPL"); 2512