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) ? EBT_MATCH : EBT_NOMATCH; 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 /* Do some firewalling */ 181 unsigned int ebt_do_table(struct sk_buff *skb, 182 const struct nf_hook_state *state, 183 struct ebt_table *table) 184 { 185 unsigned int hook = state->hook; 186 int i, nentries; 187 struct ebt_entry *point; 188 struct ebt_counter *counter_base, *cb_base; 189 const struct ebt_entry_target *t; 190 int verdict, sp = 0; 191 struct ebt_chainstack *cs; 192 struct ebt_entries *chaininfo; 193 const char *base; 194 const struct ebt_table_info *private; 195 struct xt_action_param acpar; 196 197 acpar.state = state; 198 acpar.hotdrop = false; 199 200 read_lock_bh(&table->lock); 201 private = table->private; 202 cb_base = COUNTER_BASE(private->counters, private->nentries, 203 smp_processor_id()); 204 if (private->chainstack) 205 cs = private->chainstack[smp_processor_id()]; 206 else 207 cs = NULL; 208 chaininfo = private->hook_entry[hook]; 209 nentries = private->hook_entry[hook]->nentries; 210 point = (struct ebt_entry *)(private->hook_entry[hook]->data); 211 counter_base = cb_base + private->hook_entry[hook]->counter_offset; 212 /* base for chain jumps */ 213 base = private->entries; 214 i = 0; 215 while (i < nentries) { 216 if (ebt_basic_match(point, skb, state->in, state->out)) 217 goto letscontinue; 218 219 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0) 220 goto letscontinue; 221 if (acpar.hotdrop) { 222 read_unlock_bh(&table->lock); 223 return NF_DROP; 224 } 225 226 /* increase counter */ 227 (*(counter_base + i)).pcnt++; 228 (*(counter_base + i)).bcnt += skb->len; 229 230 /* these should only watch: not modify, nor tell us 231 * what to do with the packet 232 */ 233 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar); 234 235 t = (struct ebt_entry_target *) 236 (((char *)point) + point->target_offset); 237 /* standard target */ 238 if (!t->u.target->target) 239 verdict = ((struct ebt_standard_target *)t)->verdict; 240 else { 241 acpar.target = t->u.target; 242 acpar.targinfo = t->data; 243 verdict = t->u.target->target(skb, &acpar); 244 } 245 if (verdict == EBT_ACCEPT) { 246 read_unlock_bh(&table->lock); 247 return NF_ACCEPT; 248 } 249 if (verdict == EBT_DROP) { 250 read_unlock_bh(&table->lock); 251 return NF_DROP; 252 } 253 if (verdict == EBT_RETURN) { 254 letsreturn: 255 #ifdef CONFIG_NETFILTER_DEBUG 256 if (sp == 0) { 257 BUGPRINT("RETURN on base chain"); 258 /* act like this is EBT_CONTINUE */ 259 goto letscontinue; 260 } 261 #endif 262 sp--; 263 /* put all the local variables right */ 264 i = cs[sp].n; 265 chaininfo = cs[sp].chaininfo; 266 nentries = chaininfo->nentries; 267 point = cs[sp].e; 268 counter_base = cb_base + 269 chaininfo->counter_offset; 270 continue; 271 } 272 if (verdict == EBT_CONTINUE) 273 goto letscontinue; 274 #ifdef CONFIG_NETFILTER_DEBUG 275 if (verdict < 0) { 276 BUGPRINT("bogus standard verdict\n"); 277 read_unlock_bh(&table->lock); 278 return NF_DROP; 279 } 280 #endif 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 #ifdef CONFIG_NETFILTER_DEBUG 288 if (chaininfo->distinguisher) { 289 BUGPRINT("jump to non-chain\n"); 290 read_unlock_bh(&table->lock); 291 return NF_DROP; 292 } 293 #endif 294 nentries = chaininfo->nentries; 295 point = (struct ebt_entry *)chaininfo->data; 296 counter_base = cb_base + chaininfo->counter_offset; 297 sp++; 298 continue; 299 letscontinue: 300 point = ebt_next_entry(point); 301 i++; 302 } 303 304 /* I actually like this :) */ 305 if (chaininfo->policy == EBT_RETURN) 306 goto letsreturn; 307 if (chaininfo->policy == EBT_ACCEPT) { 308 read_unlock_bh(&table->lock); 309 return NF_ACCEPT; 310 } 311 read_unlock_bh(&table->lock); 312 return NF_DROP; 313 } 314 315 /* If it succeeds, returns element and locks mutex */ 316 static inline void * 317 find_inlist_lock_noload(struct list_head *head, const char *name, int *error, 318 struct mutex *mutex) 319 { 320 struct { 321 struct list_head list; 322 char name[EBT_FUNCTION_MAXNAMELEN]; 323 } *e; 324 325 mutex_lock(mutex); 326 list_for_each_entry(e, head, list) { 327 if (strcmp(e->name, name) == 0) 328 return e; 329 } 330 *error = -ENOENT; 331 mutex_unlock(mutex); 332 return NULL; 333 } 334 335 static void * 336 find_inlist_lock(struct list_head *head, const char *name, const char *prefix, 337 int *error, struct mutex *mutex) 338 { 339 return try_then_request_module( 340 find_inlist_lock_noload(head, name, error, mutex), 341 "%s%s", prefix, name); 342 } 343 344 static inline struct ebt_table * 345 find_table_lock(struct net *net, const char *name, int *error, 346 struct mutex *mutex) 347 { 348 return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name, 349 "ebtable_", error, mutex); 350 } 351 352 static inline int 353 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, 354 unsigned int *cnt) 355 { 356 const struct ebt_entry *e = par->entryinfo; 357 struct xt_match *match; 358 size_t left = ((char *)e + e->watchers_offset) - (char *)m; 359 int ret; 360 361 if (left < sizeof(struct ebt_entry_match) || 362 left - sizeof(struct ebt_entry_match) < m->match_size) 363 return -EINVAL; 364 365 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); 366 if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { 367 if (!IS_ERR(match)) 368 module_put(match->me); 369 request_module("ebt_%s", m->u.name); 370 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); 371 } 372 if (IS_ERR(match)) 373 return PTR_ERR(match); 374 m->u.match = match; 375 376 par->match = match; 377 par->matchinfo = m->data; 378 ret = xt_check_match(par, m->match_size, 379 e->ethproto, e->invflags & EBT_IPROTO); 380 if (ret < 0) { 381 module_put(match->me); 382 return ret; 383 } 384 385 (*cnt)++; 386 return 0; 387 } 388 389 static inline int 390 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par, 391 unsigned int *cnt) 392 { 393 const struct ebt_entry *e = par->entryinfo; 394 struct xt_target *watcher; 395 size_t left = ((char *)e + e->target_offset) - (char *)w; 396 int ret; 397 398 if (left < sizeof(struct ebt_entry_watcher) || 399 left - sizeof(struct ebt_entry_watcher) < w->watcher_size) 400 return -EINVAL; 401 402 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); 403 if (IS_ERR(watcher)) 404 return PTR_ERR(watcher); 405 w->u.watcher = watcher; 406 407 par->target = watcher; 408 par->targinfo = w->data; 409 ret = xt_check_target(par, w->watcher_size, 410 e->ethproto, e->invflags & EBT_IPROTO); 411 if (ret < 0) { 412 module_put(watcher->me); 413 return ret; 414 } 415 416 (*cnt)++; 417 return 0; 418 } 419 420 static int ebt_verify_pointers(const struct ebt_replace *repl, 421 struct ebt_table_info *newinfo) 422 { 423 unsigned int limit = repl->entries_size; 424 unsigned int valid_hooks = repl->valid_hooks; 425 unsigned int offset = 0; 426 int i; 427 428 for (i = 0; i < NF_BR_NUMHOOKS; i++) 429 newinfo->hook_entry[i] = NULL; 430 431 newinfo->entries_size = repl->entries_size; 432 newinfo->nentries = repl->nentries; 433 434 while (offset < limit) { 435 size_t left = limit - offset; 436 struct ebt_entry *e = (void *)newinfo->entries + offset; 437 438 if (left < sizeof(unsigned int)) 439 break; 440 441 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 442 if ((valid_hooks & (1 << i)) == 0) 443 continue; 444 if ((char __user *)repl->hook_entry[i] == 445 repl->entries + offset) 446 break; 447 } 448 449 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { 450 if (e->bitmask != 0) { 451 /* we make userspace set this right, 452 * so there is no misunderstanding 453 */ 454 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set " 455 "in distinguisher\n"); 456 return -EINVAL; 457 } 458 if (i != NF_BR_NUMHOOKS) 459 newinfo->hook_entry[i] = (struct ebt_entries *)e; 460 if (left < sizeof(struct ebt_entries)) 461 break; 462 offset += sizeof(struct ebt_entries); 463 } else { 464 if (left < sizeof(struct ebt_entry)) 465 break; 466 if (left < e->next_offset) 467 break; 468 if (e->next_offset < sizeof(struct ebt_entry)) 469 return -EINVAL; 470 offset += e->next_offset; 471 } 472 } 473 if (offset != limit) { 474 BUGPRINT("entries_size too small\n"); 475 return -EINVAL; 476 } 477 478 /* check if all valid hooks have a chain */ 479 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 480 if (!newinfo->hook_entry[i] && 481 (valid_hooks & (1 << i))) { 482 BUGPRINT("Valid hook without chain\n"); 483 return -EINVAL; 484 } 485 } 486 return 0; 487 } 488 489 /* this one is very careful, as it is the first function 490 * to parse the userspace data 491 */ 492 static inline int 493 ebt_check_entry_size_and_hooks(const struct ebt_entry *e, 494 const struct ebt_table_info *newinfo, 495 unsigned int *n, unsigned int *cnt, 496 unsigned int *totalcnt, unsigned int *udc_cnt) 497 { 498 int i; 499 500 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 501 if ((void *)e == (void *)newinfo->hook_entry[i]) 502 break; 503 } 504 /* beginning of a new chain 505 * if i == NF_BR_NUMHOOKS it must be a user defined chain 506 */ 507 if (i != NF_BR_NUMHOOKS || !e->bitmask) { 508 /* this checks if the previous chain has as many entries 509 * as it said it has 510 */ 511 if (*n != *cnt) { 512 BUGPRINT("nentries does not equal the nr of entries " 513 "in the chain\n"); 514 return -EINVAL; 515 } 516 if (((struct ebt_entries *)e)->policy != EBT_DROP && 517 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { 518 /* only RETURN from udc */ 519 if (i != NF_BR_NUMHOOKS || 520 ((struct ebt_entries *)e)->policy != EBT_RETURN) { 521 BUGPRINT("bad policy\n"); 522 return -EINVAL; 523 } 524 } 525 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ 526 (*udc_cnt)++; 527 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) { 528 BUGPRINT("counter_offset != totalcnt"); 529 return -EINVAL; 530 } 531 *n = ((struct ebt_entries *)e)->nentries; 532 *cnt = 0; 533 return 0; 534 } 535 /* a plain old entry, heh */ 536 if (sizeof(struct ebt_entry) > e->watchers_offset || 537 e->watchers_offset > e->target_offset || 538 e->target_offset >= e->next_offset) { 539 BUGPRINT("entry offsets not in right order\n"); 540 return -EINVAL; 541 } 542 /* this is not checked anywhere else */ 543 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) { 544 BUGPRINT("target size too small\n"); 545 return -EINVAL; 546 } 547 (*cnt)++; 548 (*totalcnt)++; 549 return 0; 550 } 551 552 struct ebt_cl_stack { 553 struct ebt_chainstack cs; 554 int from; 555 unsigned int hookmask; 556 }; 557 558 /* We need these positions to check that the jumps to a different part of the 559 * entries is a jump to the beginning of a new chain. 560 */ 561 static inline int 562 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, 563 unsigned int *n, struct ebt_cl_stack *udc) 564 { 565 int i; 566 567 /* we're only interested in chain starts */ 568 if (e->bitmask) 569 return 0; 570 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 571 if (newinfo->hook_entry[i] == (struct ebt_entries *)e) 572 break; 573 } 574 /* only care about udc */ 575 if (i != NF_BR_NUMHOOKS) 576 return 0; 577 578 udc[*n].cs.chaininfo = (struct ebt_entries *)e; 579 /* these initialisations are depended on later in check_chainloops() */ 580 udc[*n].cs.n = 0; 581 udc[*n].hookmask = 0; 582 583 (*n)++; 584 return 0; 585 } 586 587 static inline int 588 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i) 589 { 590 struct xt_mtdtor_param par; 591 592 if (i && (*i)-- == 0) 593 return 1; 594 595 par.net = net; 596 par.match = m->u.match; 597 par.matchinfo = m->data; 598 par.family = NFPROTO_BRIDGE; 599 if (par.match->destroy != NULL) 600 par.match->destroy(&par); 601 module_put(par.match->me); 602 return 0; 603 } 604 605 static inline int 606 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i) 607 { 608 struct xt_tgdtor_param par; 609 610 if (i && (*i)-- == 0) 611 return 1; 612 613 par.net = net; 614 par.target = w->u.watcher; 615 par.targinfo = w->data; 616 par.family = NFPROTO_BRIDGE; 617 if (par.target->destroy != NULL) 618 par.target->destroy(&par); 619 module_put(par.target->me); 620 return 0; 621 } 622 623 static inline int 624 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt) 625 { 626 struct xt_tgdtor_param par; 627 struct ebt_entry_target *t; 628 629 if (e->bitmask == 0) 630 return 0; 631 /* we're done */ 632 if (cnt && (*cnt)-- == 0) 633 return 1; 634 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL); 635 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL); 636 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); 637 638 par.net = net; 639 par.target = t->u.target; 640 par.targinfo = t->data; 641 par.family = NFPROTO_BRIDGE; 642 if (par.target->destroy != NULL) 643 par.target->destroy(&par); 644 module_put(par.target->me); 645 return 0; 646 } 647 648 static inline int 649 ebt_check_entry(struct ebt_entry *e, struct net *net, 650 const struct ebt_table_info *newinfo, 651 const char *name, unsigned int *cnt, 652 struct ebt_cl_stack *cl_s, unsigned int udc_cnt) 653 { 654 struct ebt_entry_target *t; 655 struct xt_target *target; 656 unsigned int i, j, hook = 0, hookmask = 0; 657 size_t gap; 658 int ret; 659 struct xt_mtchk_param mtpar; 660 struct xt_tgchk_param tgpar; 661 662 /* don't mess with the struct ebt_entries */ 663 if (e->bitmask == 0) 664 return 0; 665 666 if (e->bitmask & ~EBT_F_MASK) { 667 BUGPRINT("Unknown flag for bitmask\n"); 668 return -EINVAL; 669 } 670 if (e->invflags & ~EBT_INV_MASK) { 671 BUGPRINT("Unknown flag for inv bitmask\n"); 672 return -EINVAL; 673 } 674 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) { 675 BUGPRINT("NOPROTO & 802_3 not allowed\n"); 676 return -EINVAL; 677 } 678 /* what hook do we belong to? */ 679 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 680 if (!newinfo->hook_entry[i]) 681 continue; 682 if ((char *)newinfo->hook_entry[i] < (char *)e) 683 hook = i; 684 else 685 break; 686 } 687 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on 688 * a base chain 689 */ 690 if (i < NF_BR_NUMHOOKS) 691 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 692 else { 693 for (i = 0; i < udc_cnt; i++) 694 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) 695 break; 696 if (i == 0) 697 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); 698 else 699 hookmask = cl_s[i - 1].hookmask; 700 } 701 i = 0; 702 703 mtpar.net = tgpar.net = net; 704 mtpar.table = tgpar.table = name; 705 mtpar.entryinfo = tgpar.entryinfo = e; 706 mtpar.hook_mask = tgpar.hook_mask = hookmask; 707 mtpar.family = tgpar.family = NFPROTO_BRIDGE; 708 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i); 709 if (ret != 0) 710 goto cleanup_matches; 711 j = 0; 712 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j); 713 if (ret != 0) 714 goto cleanup_watchers; 715 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); 716 gap = e->next_offset - e->target_offset; 717 718 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0); 719 if (IS_ERR(target)) { 720 ret = PTR_ERR(target); 721 goto cleanup_watchers; 722 } 723 724 t->u.target = target; 725 if (t->u.target == &ebt_standard_target) { 726 if (gap < sizeof(struct ebt_standard_target)) { 727 BUGPRINT("Standard target size too big\n"); 728 ret = -EFAULT; 729 goto cleanup_watchers; 730 } 731 if (((struct ebt_standard_target *)t)->verdict < 732 -NUM_STANDARD_TARGETS) { 733 BUGPRINT("Invalid standard target\n"); 734 ret = -EFAULT; 735 goto cleanup_watchers; 736 } 737 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) { 738 module_put(t->u.target->me); 739 ret = -EFAULT; 740 goto cleanup_watchers; 741 } 742 743 tgpar.target = target; 744 tgpar.targinfo = t->data; 745 ret = xt_check_target(&tgpar, t->target_size, 746 e->ethproto, e->invflags & EBT_IPROTO); 747 if (ret < 0) { 748 module_put(target->me); 749 goto cleanup_watchers; 750 } 751 (*cnt)++; 752 return 0; 753 cleanup_watchers: 754 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j); 755 cleanup_matches: 756 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i); 757 return ret; 758 } 759 760 /* checks for loops and sets the hook mask for udc 761 * the hook mask for udc tells us from which base chains the udc can be 762 * accessed. This mask is a parameter to the check() functions of the extensions 763 */ 764 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s, 765 unsigned int udc_cnt, unsigned int hooknr, char *base) 766 { 767 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; 768 const struct ebt_entry *e = (struct ebt_entry *)chain->data; 769 const struct ebt_entry_target *t; 770 771 while (pos < nentries || chain_nr != -1) { 772 /* end of udc, go back one 'recursion' step */ 773 if (pos == nentries) { 774 /* put back values of the time when this chain was called */ 775 e = cl_s[chain_nr].cs.e; 776 if (cl_s[chain_nr].from != -1) 777 nentries = 778 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; 779 else 780 nentries = chain->nentries; 781 pos = cl_s[chain_nr].cs.n; 782 /* make sure we won't see a loop that isn't one */ 783 cl_s[chain_nr].cs.n = 0; 784 chain_nr = cl_s[chain_nr].from; 785 if (pos == nentries) 786 continue; 787 } 788 t = (struct ebt_entry_target *) 789 (((char *)e) + e->target_offset); 790 if (strcmp(t->u.name, EBT_STANDARD_TARGET)) 791 goto letscontinue; 792 if (e->target_offset + sizeof(struct ebt_standard_target) > 793 e->next_offset) { 794 BUGPRINT("Standard target size too big\n"); 795 return -1; 796 } 797 verdict = ((struct ebt_standard_target *)t)->verdict; 798 if (verdict >= 0) { /* jump to another chain */ 799 struct ebt_entries *hlp2 = 800 (struct ebt_entries *)(base + verdict); 801 for (i = 0; i < udc_cnt; i++) 802 if (hlp2 == cl_s[i].cs.chaininfo) 803 break; 804 /* bad destination or loop */ 805 if (i == udc_cnt) { 806 BUGPRINT("bad destination\n"); 807 return -1; 808 } 809 if (cl_s[i].cs.n) { 810 BUGPRINT("loop\n"); 811 return -1; 812 } 813 if (cl_s[i].hookmask & (1 << hooknr)) 814 goto letscontinue; 815 /* this can't be 0, so the loop test is correct */ 816 cl_s[i].cs.n = pos + 1; 817 pos = 0; 818 cl_s[i].cs.e = ebt_next_entry(e); 819 e = (struct ebt_entry *)(hlp2->data); 820 nentries = hlp2->nentries; 821 cl_s[i].from = chain_nr; 822 chain_nr = i; 823 /* this udc is accessible from the base chain for hooknr */ 824 cl_s[i].hookmask |= (1 << hooknr); 825 continue; 826 } 827 letscontinue: 828 e = ebt_next_entry(e); 829 pos++; 830 } 831 return 0; 832 } 833 834 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ 835 static int translate_table(struct net *net, const char *name, 836 struct ebt_table_info *newinfo) 837 { 838 unsigned int i, j, k, udc_cnt; 839 int ret; 840 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ 841 842 i = 0; 843 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i]) 844 i++; 845 if (i == NF_BR_NUMHOOKS) { 846 BUGPRINT("No valid hooks specified\n"); 847 return -EINVAL; 848 } 849 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) { 850 BUGPRINT("Chains don't start at beginning\n"); 851 return -EINVAL; 852 } 853 /* make sure chains are ordered after each other in same order 854 * as their corresponding hooks 855 */ 856 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { 857 if (!newinfo->hook_entry[j]) 858 continue; 859 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) { 860 BUGPRINT("Hook order must be followed\n"); 861 return -EINVAL; 862 } 863 i = j; 864 } 865 866 /* do some early checkings and initialize some things */ 867 i = 0; /* holds the expected nr. of entries for the chain */ 868 j = 0; /* holds the up to now counted entries for the chain */ 869 k = 0; /* holds the total nr. of entries, should equal 870 * newinfo->nentries afterwards 871 */ 872 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ 873 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 874 ebt_check_entry_size_and_hooks, newinfo, 875 &i, &j, &k, &udc_cnt); 876 877 if (ret != 0) 878 return ret; 879 880 if (i != j) { 881 BUGPRINT("nentries does not equal the nr of entries in the " 882 "(last) chain\n"); 883 return -EINVAL; 884 } 885 if (k != newinfo->nentries) { 886 BUGPRINT("Total nentries is wrong\n"); 887 return -EINVAL; 888 } 889 890 /* get the location of the udc, put them in an array 891 * while we're at it, allocate the chainstack 892 */ 893 if (udc_cnt) { 894 /* this will get free'd in do_replace()/ebt_register_table() 895 * if an error occurs 896 */ 897 newinfo->chainstack = 898 vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack))); 899 if (!newinfo->chainstack) 900 return -ENOMEM; 901 for_each_possible_cpu(i) { 902 newinfo->chainstack[i] = 903 vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0]))); 904 if (!newinfo->chainstack[i]) { 905 while (i) 906 vfree(newinfo->chainstack[--i]); 907 vfree(newinfo->chainstack); 908 newinfo->chainstack = NULL; 909 return -ENOMEM; 910 } 911 } 912 913 cl_s = vmalloc(udc_cnt * sizeof(*cl_s)); 914 if (!cl_s) 915 return -ENOMEM; 916 i = 0; /* the i'th udc */ 917 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 918 ebt_get_udc_positions, newinfo, &i, cl_s); 919 /* sanity check */ 920 if (i != udc_cnt) { 921 BUGPRINT("i != udc_cnt\n"); 922 vfree(cl_s); 923 return -EFAULT; 924 } 925 } 926 927 /* Check for loops */ 928 for (i = 0; i < NF_BR_NUMHOOKS; i++) 929 if (newinfo->hook_entry[i]) 930 if (check_chainloops(newinfo->hook_entry[i], 931 cl_s, udc_cnt, i, newinfo->entries)) { 932 vfree(cl_s); 933 return -EINVAL; 934 } 935 936 /* we now know the following (along with E=mc²): 937 * - the nr of entries in each chain is right 938 * - the size of the allocated space is right 939 * - all valid hooks have a corresponding chain 940 * - there are no loops 941 * - wrong data can still be on the level of a single entry 942 * - could be there are jumps to places that are not the 943 * beginning of a chain. This can only occur in chains that 944 * are not accessible from any base chains, so we don't care. 945 */ 946 947 /* used to know what we need to clean up if something goes wrong */ 948 i = 0; 949 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 950 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt); 951 if (ret != 0) { 952 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 953 ebt_cleanup_entry, net, &i); 954 } 955 vfree(cl_s); 956 return ret; 957 } 958 959 /* called under write_lock */ 960 static void get_counters(const struct ebt_counter *oldcounters, 961 struct ebt_counter *counters, unsigned int nentries) 962 { 963 int i, cpu; 964 struct ebt_counter *counter_base; 965 966 /* counters of cpu 0 */ 967 memcpy(counters, oldcounters, 968 sizeof(struct ebt_counter) * nentries); 969 970 /* add other counters to those of cpu 0 */ 971 for_each_possible_cpu(cpu) { 972 if (cpu == 0) 973 continue; 974 counter_base = COUNTER_BASE(oldcounters, nentries, cpu); 975 for (i = 0; i < nentries; i++) { 976 counters[i].pcnt += counter_base[i].pcnt; 977 counters[i].bcnt += counter_base[i].bcnt; 978 } 979 } 980 } 981 982 static int do_replace_finish(struct net *net, struct ebt_replace *repl, 983 struct ebt_table_info *newinfo) 984 { 985 int ret, i; 986 struct ebt_counter *counterstmp = NULL; 987 /* used to be able to unlock earlier */ 988 struct ebt_table_info *table; 989 struct ebt_table *t; 990 991 /* the user wants counters back 992 * the check on the size is done later, when we have the lock 993 */ 994 if (repl->num_counters) { 995 unsigned long size = repl->num_counters * sizeof(*counterstmp); 996 counterstmp = vmalloc(size); 997 if (!counterstmp) 998 return -ENOMEM; 999 } 1000 1001 newinfo->chainstack = NULL; 1002 ret = ebt_verify_pointers(repl, newinfo); 1003 if (ret != 0) 1004 goto free_counterstmp; 1005 1006 ret = translate_table(net, repl->name, newinfo); 1007 1008 if (ret != 0) 1009 goto free_counterstmp; 1010 1011 t = find_table_lock(net, repl->name, &ret, &ebt_mutex); 1012 if (!t) { 1013 ret = -ENOENT; 1014 goto free_iterate; 1015 } 1016 1017 /* the table doesn't like it */ 1018 if (t->check && (ret = t->check(newinfo, repl->valid_hooks))) 1019 goto free_unlock; 1020 1021 if (repl->num_counters && repl->num_counters != t->private->nentries) { 1022 BUGPRINT("Wrong nr. of counters requested\n"); 1023 ret = -EINVAL; 1024 goto free_unlock; 1025 } 1026 1027 /* we have the mutex lock, so no danger in reading this pointer */ 1028 table = t->private; 1029 /* make sure the table can only be rmmod'ed if it contains no rules */ 1030 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) { 1031 ret = -ENOENT; 1032 goto free_unlock; 1033 } else if (table->nentries && !newinfo->nentries) 1034 module_put(t->me); 1035 /* we need an atomic snapshot of the counters */ 1036 write_lock_bh(&t->lock); 1037 if (repl->num_counters) 1038 get_counters(t->private->counters, counterstmp, 1039 t->private->nentries); 1040 1041 t->private = newinfo; 1042 write_unlock_bh(&t->lock); 1043 mutex_unlock(&ebt_mutex); 1044 /* so, a user can change the chains while having messed up her counter 1045 * allocation. Only reason why this is done is because this way the lock 1046 * is held only once, while this doesn't bring the kernel into a 1047 * dangerous state. 1048 */ 1049 if (repl->num_counters && 1050 copy_to_user(repl->counters, counterstmp, 1051 repl->num_counters * sizeof(struct ebt_counter))) { 1052 /* Silent error, can't fail, new table is already in place */ 1053 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n"); 1054 } 1055 1056 /* decrease module count and free resources */ 1057 EBT_ENTRY_ITERATE(table->entries, table->entries_size, 1058 ebt_cleanup_entry, net, NULL); 1059 1060 vfree(table->entries); 1061 if (table->chainstack) { 1062 for_each_possible_cpu(i) 1063 vfree(table->chainstack[i]); 1064 vfree(table->chainstack); 1065 } 1066 vfree(table); 1067 1068 vfree(counterstmp); 1069 1070 #ifdef CONFIG_AUDIT 1071 if (audit_enabled) { 1072 struct audit_buffer *ab; 1073 1074 ab = audit_log_start(current->audit_context, GFP_KERNEL, 1075 AUDIT_NETFILTER_CFG); 1076 if (ab) { 1077 audit_log_format(ab, "table=%s family=%u entries=%u", 1078 repl->name, AF_BRIDGE, repl->nentries); 1079 audit_log_end(ab); 1080 } 1081 } 1082 #endif 1083 return ret; 1084 1085 free_unlock: 1086 mutex_unlock(&ebt_mutex); 1087 free_iterate: 1088 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, 1089 ebt_cleanup_entry, net, NULL); 1090 free_counterstmp: 1091 vfree(counterstmp); 1092 /* can be initialized in translate_table() */ 1093 if (newinfo->chainstack) { 1094 for_each_possible_cpu(i) 1095 vfree(newinfo->chainstack[i]); 1096 vfree(newinfo->chainstack); 1097 } 1098 return ret; 1099 } 1100 1101 /* replace the table */ 1102 static int do_replace(struct net *net, const void __user *user, 1103 unsigned int len) 1104 { 1105 int ret, countersize; 1106 struct ebt_table_info *newinfo; 1107 struct ebt_replace tmp; 1108 1109 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1110 return -EFAULT; 1111 1112 if (len != sizeof(tmp) + tmp.entries_size) { 1113 BUGPRINT("Wrong len argument\n"); 1114 return -EINVAL; 1115 } 1116 1117 if (tmp.entries_size == 0) { 1118 BUGPRINT("Entries_size never zero\n"); 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); 1132 if (!newinfo) 1133 return -ENOMEM; 1134 1135 if (countersize) 1136 memset(newinfo->counters, 0, countersize); 1137 1138 newinfo->entries = vmalloc(tmp.entries_size); 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 BUGPRINT("Couldn't copy entries from userspace\n"); 1146 ret = -EFAULT; 1147 goto free_entries; 1148 } 1149 1150 ret = do_replace_finish(net, &tmp, newinfo); 1151 if (ret == 0) 1152 return ret; 1153 free_entries: 1154 vfree(newinfo->entries); 1155 free_newinfo: 1156 vfree(newinfo); 1157 return ret; 1158 } 1159 1160 static void __ebt_unregister_table(struct net *net, struct ebt_table *table) 1161 { 1162 int i; 1163 1164 mutex_lock(&ebt_mutex); 1165 list_del(&table->list); 1166 mutex_unlock(&ebt_mutex); 1167 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size, 1168 ebt_cleanup_entry, net, NULL); 1169 if (table->private->nentries) 1170 module_put(table->me); 1171 vfree(table->private->entries); 1172 if (table->private->chainstack) { 1173 for_each_possible_cpu(i) 1174 vfree(table->private->chainstack[i]); 1175 vfree(table->private->chainstack); 1176 } 1177 vfree(table->private); 1178 kfree(table); 1179 } 1180 1181 struct ebt_table * 1182 ebt_register_table(struct net *net, const struct ebt_table *input_table, 1183 const struct nf_hook_ops *ops) 1184 { 1185 struct ebt_table_info *newinfo; 1186 struct ebt_table *t, *table; 1187 struct ebt_replace_kernel *repl; 1188 int ret, i, countersize; 1189 void *p; 1190 1191 if (input_table == NULL || (repl = input_table->table) == NULL || 1192 repl->entries == NULL || repl->entries_size == 0 || 1193 repl->counters != NULL || input_table->private != NULL) { 1194 BUGPRINT("Bad table data for ebt_register_table!!!\n"); 1195 return ERR_PTR(-EINVAL); 1196 } 1197 1198 /* Don't add one table to multiple lists. */ 1199 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL); 1200 if (!table) { 1201 ret = -ENOMEM; 1202 goto out; 1203 } 1204 1205 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids; 1206 newinfo = vmalloc(sizeof(*newinfo) + countersize); 1207 ret = -ENOMEM; 1208 if (!newinfo) 1209 goto free_table; 1210 1211 p = vmalloc(repl->entries_size); 1212 if (!p) 1213 goto free_newinfo; 1214 1215 memcpy(p, repl->entries, repl->entries_size); 1216 newinfo->entries = p; 1217 1218 newinfo->entries_size = repl->entries_size; 1219 newinfo->nentries = repl->nentries; 1220 1221 if (countersize) 1222 memset(newinfo->counters, 0, countersize); 1223 1224 /* fill in newinfo and parse the entries */ 1225 newinfo->chainstack = NULL; 1226 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1227 if ((repl->valid_hooks & (1 << i)) == 0) 1228 newinfo->hook_entry[i] = NULL; 1229 else 1230 newinfo->hook_entry[i] = p + 1231 ((char *)repl->hook_entry[i] - repl->entries); 1232 } 1233 ret = translate_table(net, repl->name, newinfo); 1234 if (ret != 0) { 1235 BUGPRINT("Translate_table failed\n"); 1236 goto free_chainstack; 1237 } 1238 1239 if (table->check && table->check(newinfo, table->valid_hooks)) { 1240 BUGPRINT("The table doesn't like its own initial data, lol\n"); 1241 ret = -EINVAL; 1242 goto free_chainstack; 1243 } 1244 1245 table->private = newinfo; 1246 rwlock_init(&table->lock); 1247 mutex_lock(&ebt_mutex); 1248 list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) { 1249 if (strcmp(t->name, table->name) == 0) { 1250 ret = -EEXIST; 1251 BUGPRINT("Table name already exists\n"); 1252 goto free_unlock; 1253 } 1254 } 1255 1256 /* Hold a reference count if the chains aren't empty */ 1257 if (newinfo->nentries && !try_module_get(table->me)) { 1258 ret = -ENOENT; 1259 goto free_unlock; 1260 } 1261 list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]); 1262 mutex_unlock(&ebt_mutex); 1263 1264 if (!ops) 1265 return table; 1266 1267 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1268 if (ret) { 1269 __ebt_unregister_table(net, table); 1270 return ERR_PTR(ret); 1271 } 1272 1273 return table; 1274 free_unlock: 1275 mutex_unlock(&ebt_mutex); 1276 free_chainstack: 1277 if (newinfo->chainstack) { 1278 for_each_possible_cpu(i) 1279 vfree(newinfo->chainstack[i]); 1280 vfree(newinfo->chainstack); 1281 } 1282 vfree(newinfo->entries); 1283 free_newinfo: 1284 vfree(newinfo); 1285 free_table: 1286 kfree(table); 1287 out: 1288 return ERR_PTR(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(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 t->private->counters[i].pcnt += tmp[i].pcnt; 1337 t->private->counters[i].bcnt += tmp[i].bcnt; 1338 } 1339 1340 write_unlock_bh(&t->lock); 1341 ret = 0; 1342 unlock_mutex: 1343 mutex_unlock(&ebt_mutex); 1344 free_tmp: 1345 vfree(tmp); 1346 return ret; 1347 } 1348 1349 static int update_counters(struct net *net, const void __user *user, 1350 unsigned int len) 1351 { 1352 struct ebt_replace hlp; 1353 1354 if (copy_from_user(&hlp, user, sizeof(hlp))) 1355 return -EFAULT; 1356 1357 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 1358 return -EINVAL; 1359 1360 return do_update_counters(net, hlp.name, hlp.counters, 1361 hlp.num_counters, user, len); 1362 } 1363 1364 static inline int ebt_obj_to_user(char __user *um, const char *_name, 1365 const char *data, int entrysize, 1366 int usersize, int datasize) 1367 { 1368 char name[EBT_FUNCTION_MAXNAMELEN] = {0}; 1369 1370 /* ebtables expects 32 bytes long names but xt_match names are 29 bytes 1371 * long. Copy 29 bytes and fill remaining bytes with zeroes. 1372 */ 1373 strlcpy(name, _name, sizeof(name)); 1374 if (copy_to_user(um, name, EBT_FUNCTION_MAXNAMELEN) || 1375 put_user(datasize, (int __user *)(um + EBT_FUNCTION_MAXNAMELEN)) || 1376 xt_data_to_user(um + entrysize, data, usersize, datasize, 1377 XT_ALIGN(datasize))) 1378 return -EFAULT; 1379 1380 return 0; 1381 } 1382 1383 static inline int ebt_match_to_user(const struct ebt_entry_match *m, 1384 const char *base, char __user *ubase) 1385 { 1386 return ebt_obj_to_user(ubase + ((char *)m - base), 1387 m->u.match->name, m->data, sizeof(*m), 1388 m->u.match->usersize, m->match_size); 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 } 1398 1399 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base, 1400 char __user *ubase) 1401 { 1402 int ret; 1403 char __user *hlp; 1404 const struct ebt_entry_target *t; 1405 1406 if (e->bitmask == 0) { 1407 /* special case !EBT_ENTRY_OR_ENTRIES */ 1408 if (copy_to_user(ubase + ((char *)e - base), e, 1409 sizeof(struct ebt_entries))) 1410 return -EFAULT; 1411 return 0; 1412 } 1413 1414 if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e))) 1415 return -EFAULT; 1416 1417 hlp = ubase + (((char *)e + e->target_offset) - base); 1418 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); 1419 1420 ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase); 1421 if (ret != 0) 1422 return ret; 1423 ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase); 1424 if (ret != 0) 1425 return ret; 1426 ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t), 1427 t->u.target->usersize, t->target_size); 1428 if (ret != 0) 1429 return ret; 1430 1431 return 0; 1432 } 1433 1434 static int copy_counters_to_user(struct ebt_table *t, 1435 const struct ebt_counter *oldcounters, 1436 void __user *user, unsigned int num_counters, 1437 unsigned int nentries) 1438 { 1439 struct ebt_counter *counterstmp; 1440 int ret = 0; 1441 1442 /* userspace might not need the counters */ 1443 if (num_counters == 0) 1444 return 0; 1445 1446 if (num_counters != nentries) { 1447 BUGPRINT("Num_counters wrong\n"); 1448 return -EINVAL; 1449 } 1450 1451 counterstmp = vmalloc(nentries * sizeof(*counterstmp)); 1452 if (!counterstmp) 1453 return -ENOMEM; 1454 1455 write_lock_bh(&t->lock); 1456 get_counters(oldcounters, counterstmp, nentries); 1457 write_unlock_bh(&t->lock); 1458 1459 if (copy_to_user(user, counterstmp, 1460 nentries * sizeof(struct ebt_counter))) 1461 ret = -EFAULT; 1462 vfree(counterstmp); 1463 return ret; 1464 } 1465 1466 /* called with ebt_mutex locked */ 1467 static int copy_everything_to_user(struct ebt_table *t, void __user *user, 1468 const int *len, int cmd) 1469 { 1470 struct ebt_replace tmp; 1471 const struct ebt_counter *oldcounters; 1472 unsigned int entries_size, nentries; 1473 int ret; 1474 char *entries; 1475 1476 if (cmd == EBT_SO_GET_ENTRIES) { 1477 entries_size = t->private->entries_size; 1478 nentries = t->private->nentries; 1479 entries = t->private->entries; 1480 oldcounters = t->private->counters; 1481 } else { 1482 entries_size = t->table->entries_size; 1483 nentries = t->table->nentries; 1484 entries = t->table->entries; 1485 oldcounters = t->table->counters; 1486 } 1487 1488 if (copy_from_user(&tmp, user, sizeof(tmp))) 1489 return -EFAULT; 1490 1491 if (*len != sizeof(struct ebt_replace) + entries_size + 1492 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0)) 1493 return -EINVAL; 1494 1495 if (tmp.nentries != nentries) { 1496 BUGPRINT("Nentries wrong\n"); 1497 return -EINVAL; 1498 } 1499 1500 if (tmp.entries_size != entries_size) { 1501 BUGPRINT("Wrong size\n"); 1502 return -EINVAL; 1503 } 1504 1505 ret = copy_counters_to_user(t, oldcounters, tmp.counters, 1506 tmp.num_counters, nentries); 1507 if (ret) 1508 return ret; 1509 1510 /* set the match/watcher/target names right */ 1511 return EBT_ENTRY_ITERATE(entries, entries_size, 1512 ebt_entry_to_user, entries, tmp.entries); 1513 } 1514 1515 static int do_ebt_set_ctl(struct sock *sk, 1516 int cmd, void __user *user, unsigned int len) 1517 { 1518 int ret; 1519 struct net *net = sock_net(sk); 1520 1521 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1522 return -EPERM; 1523 1524 switch (cmd) { 1525 case EBT_SO_SET_ENTRIES: 1526 ret = do_replace(net, user, len); 1527 break; 1528 case EBT_SO_SET_COUNTERS: 1529 ret = update_counters(net, user, len); 1530 break; 1531 default: 1532 ret = -EINVAL; 1533 } 1534 return ret; 1535 } 1536 1537 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1538 { 1539 int ret; 1540 struct ebt_replace tmp; 1541 struct ebt_table *t; 1542 struct net *net = sock_net(sk); 1543 1544 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1545 return -EPERM; 1546 1547 if (copy_from_user(&tmp, user, sizeof(tmp))) 1548 return -EFAULT; 1549 1550 tmp.name[sizeof(tmp.name) - 1] = '\0'; 1551 1552 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 1553 if (!t) 1554 return ret; 1555 1556 switch (cmd) { 1557 case EBT_SO_GET_INFO: 1558 case EBT_SO_GET_INIT_INFO: 1559 if (*len != sizeof(struct ebt_replace)) { 1560 ret = -EINVAL; 1561 mutex_unlock(&ebt_mutex); 1562 break; 1563 } 1564 if (cmd == EBT_SO_GET_INFO) { 1565 tmp.nentries = t->private->nentries; 1566 tmp.entries_size = t->private->entries_size; 1567 tmp.valid_hooks = t->valid_hooks; 1568 } else { 1569 tmp.nentries = t->table->nentries; 1570 tmp.entries_size = t->table->entries_size; 1571 tmp.valid_hooks = t->table->valid_hooks; 1572 } 1573 mutex_unlock(&ebt_mutex); 1574 if (copy_to_user(user, &tmp, *len) != 0) { 1575 BUGPRINT("c2u Didn't work\n"); 1576 ret = -EFAULT; 1577 break; 1578 } 1579 ret = 0; 1580 break; 1581 1582 case EBT_SO_GET_ENTRIES: 1583 case EBT_SO_GET_INIT_ENTRIES: 1584 ret = copy_everything_to_user(t, user, len, cmd); 1585 mutex_unlock(&ebt_mutex); 1586 break; 1587 1588 default: 1589 mutex_unlock(&ebt_mutex); 1590 ret = -EINVAL; 1591 } 1592 1593 return ret; 1594 } 1595 1596 #ifdef CONFIG_COMPAT 1597 /* 32 bit-userspace compatibility definitions. */ 1598 struct compat_ebt_replace { 1599 char name[EBT_TABLE_MAXNAMELEN]; 1600 compat_uint_t valid_hooks; 1601 compat_uint_t nentries; 1602 compat_uint_t entries_size; 1603 /* start of the chains */ 1604 compat_uptr_t hook_entry[NF_BR_NUMHOOKS]; 1605 /* nr of counters userspace expects back */ 1606 compat_uint_t num_counters; 1607 /* where the kernel will put the old counters. */ 1608 compat_uptr_t counters; 1609 compat_uptr_t entries; 1610 }; 1611 1612 /* struct ebt_entry_match, _target and _watcher have same layout */ 1613 struct compat_ebt_entry_mwt { 1614 union { 1615 char name[EBT_FUNCTION_MAXNAMELEN]; 1616 compat_uptr_t ptr; 1617 } u; 1618 compat_uint_t match_size; 1619 compat_uint_t data[0]; 1620 }; 1621 1622 /* account for possible padding between match_size and ->data */ 1623 static int ebt_compat_entry_padsize(void) 1624 { 1625 BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) < 1626 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt))); 1627 return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) - 1628 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)); 1629 } 1630 1631 static int ebt_compat_match_offset(const struct xt_match *match, 1632 unsigned int userlen) 1633 { 1634 /* ebt_among needs special handling. The kernel .matchsize is 1635 * set to -1 at registration time; at runtime an EBT_ALIGN()ed 1636 * value is expected. 1637 * Example: userspace sends 4500, ebt_among.c wants 4504. 1638 */ 1639 if (unlikely(match->matchsize == -1)) 1640 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen); 1641 return xt_compat_match_offset(match); 1642 } 1643 1644 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr, 1645 unsigned int *size) 1646 { 1647 const struct xt_match *match = m->u.match; 1648 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1649 int off = ebt_compat_match_offset(match, m->match_size); 1650 compat_uint_t msize = m->match_size - off; 1651 1652 BUG_ON(off >= m->match_size); 1653 1654 if (copy_to_user(cm->u.name, match->name, 1655 strlen(match->name) + 1) || put_user(msize, &cm->match_size)) 1656 return -EFAULT; 1657 1658 if (match->compat_to_user) { 1659 if (match->compat_to_user(cm->data, m->data)) 1660 return -EFAULT; 1661 } else { 1662 if (xt_data_to_user(cm->data, m->data, match->usersize, msize, 1663 COMPAT_XT_ALIGN(msize))) 1664 return -EFAULT; 1665 } 1666 1667 *size -= ebt_compat_entry_padsize() + off; 1668 *dstptr = cm->data; 1669 *dstptr += msize; 1670 return 0; 1671 } 1672 1673 static int compat_target_to_user(struct ebt_entry_target *t, 1674 void __user **dstptr, 1675 unsigned int *size) 1676 { 1677 const struct xt_target *target = t->u.target; 1678 struct compat_ebt_entry_mwt __user *cm = *dstptr; 1679 int off = xt_compat_target_offset(target); 1680 compat_uint_t tsize = t->target_size - off; 1681 1682 BUG_ON(off >= t->target_size); 1683 1684 if (copy_to_user(cm->u.name, target->name, 1685 strlen(target->name) + 1) || put_user(tsize, &cm->match_size)) 1686 return -EFAULT; 1687 1688 if (target->compat_to_user) { 1689 if (target->compat_to_user(cm->data, t->data)) 1690 return -EFAULT; 1691 } else { 1692 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize, 1693 COMPAT_XT_ALIGN(tsize))) 1694 return -EFAULT; 1695 } 1696 1697 *size -= ebt_compat_entry_padsize() + off; 1698 *dstptr = cm->data; 1699 *dstptr += tsize; 1700 return 0; 1701 } 1702 1703 static int compat_watcher_to_user(struct ebt_entry_watcher *w, 1704 void __user **dstptr, 1705 unsigned int *size) 1706 { 1707 return compat_target_to_user((struct ebt_entry_target *)w, 1708 dstptr, size); 1709 } 1710 1711 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr, 1712 unsigned int *size) 1713 { 1714 struct ebt_entry_target *t; 1715 struct ebt_entry __user *ce; 1716 u32 watchers_offset, target_offset, next_offset; 1717 compat_uint_t origsize; 1718 int ret; 1719 1720 if (e->bitmask == 0) { 1721 if (*size < sizeof(struct ebt_entries)) 1722 return -EINVAL; 1723 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries))) 1724 return -EFAULT; 1725 1726 *dstptr += sizeof(struct ebt_entries); 1727 *size -= sizeof(struct ebt_entries); 1728 return 0; 1729 } 1730 1731 if (*size < sizeof(*ce)) 1732 return -EINVAL; 1733 1734 ce = *dstptr; 1735 if (copy_to_user(ce, e, sizeof(*ce))) 1736 return -EFAULT; 1737 1738 origsize = *size; 1739 *dstptr += sizeof(*ce); 1740 1741 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size); 1742 if (ret) 1743 return ret; 1744 watchers_offset = e->watchers_offset - (origsize - *size); 1745 1746 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size); 1747 if (ret) 1748 return ret; 1749 target_offset = e->target_offset - (origsize - *size); 1750 1751 t = (struct ebt_entry_target *) ((char *) e + e->target_offset); 1752 1753 ret = compat_target_to_user(t, dstptr, size); 1754 if (ret) 1755 return ret; 1756 next_offset = e->next_offset - (origsize - *size); 1757 1758 if (put_user(watchers_offset, &ce->watchers_offset) || 1759 put_user(target_offset, &ce->target_offset) || 1760 put_user(next_offset, &ce->next_offset)) 1761 return -EFAULT; 1762 1763 *size -= sizeof(*ce); 1764 return 0; 1765 } 1766 1767 static int compat_calc_match(struct ebt_entry_match *m, int *off) 1768 { 1769 *off += ebt_compat_match_offset(m->u.match, m->match_size); 1770 *off += ebt_compat_entry_padsize(); 1771 return 0; 1772 } 1773 1774 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off) 1775 { 1776 *off += xt_compat_target_offset(w->u.watcher); 1777 *off += ebt_compat_entry_padsize(); 1778 return 0; 1779 } 1780 1781 static int compat_calc_entry(const struct ebt_entry *e, 1782 const struct ebt_table_info *info, 1783 const void *base, 1784 struct compat_ebt_replace *newinfo) 1785 { 1786 const struct ebt_entry_target *t; 1787 unsigned int entry_offset; 1788 int off, ret, i; 1789 1790 if (e->bitmask == 0) 1791 return 0; 1792 1793 off = 0; 1794 entry_offset = (void *)e - base; 1795 1796 EBT_MATCH_ITERATE(e, compat_calc_match, &off); 1797 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off); 1798 1799 t = (const struct ebt_entry_target *) ((char *) e + e->target_offset); 1800 1801 off += xt_compat_target_offset(t->u.target); 1802 off += ebt_compat_entry_padsize(); 1803 1804 newinfo->entries_size -= off; 1805 1806 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off); 1807 if (ret) 1808 return ret; 1809 1810 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 1811 const void *hookptr = info->hook_entry[i]; 1812 if (info->hook_entry[i] && 1813 (e < (struct ebt_entry *)(base - hookptr))) { 1814 newinfo->hook_entry[i] -= off; 1815 pr_debug("0x%08X -> 0x%08X\n", 1816 newinfo->hook_entry[i] + off, 1817 newinfo->hook_entry[i]); 1818 } 1819 } 1820 1821 return 0; 1822 } 1823 1824 1825 static int compat_table_info(const struct ebt_table_info *info, 1826 struct compat_ebt_replace *newinfo) 1827 { 1828 unsigned int size = info->entries_size; 1829 const void *entries = info->entries; 1830 1831 newinfo->entries_size = size; 1832 1833 xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries); 1834 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, 1835 entries, newinfo); 1836 } 1837 1838 static int compat_copy_everything_to_user(struct ebt_table *t, 1839 void __user *user, int *len, int cmd) 1840 { 1841 struct compat_ebt_replace repl, tmp; 1842 struct ebt_counter *oldcounters; 1843 struct ebt_table_info tinfo; 1844 int ret; 1845 void __user *pos; 1846 1847 memset(&tinfo, 0, sizeof(tinfo)); 1848 1849 if (cmd == EBT_SO_GET_ENTRIES) { 1850 tinfo.entries_size = t->private->entries_size; 1851 tinfo.nentries = t->private->nentries; 1852 tinfo.entries = t->private->entries; 1853 oldcounters = t->private->counters; 1854 } else { 1855 tinfo.entries_size = t->table->entries_size; 1856 tinfo.nentries = t->table->nentries; 1857 tinfo.entries = t->table->entries; 1858 oldcounters = t->table->counters; 1859 } 1860 1861 if (copy_from_user(&tmp, user, sizeof(tmp))) 1862 return -EFAULT; 1863 1864 if (tmp.nentries != tinfo.nentries || 1865 (tmp.num_counters && tmp.num_counters != tinfo.nentries)) 1866 return -EINVAL; 1867 1868 memcpy(&repl, &tmp, sizeof(repl)); 1869 if (cmd == EBT_SO_GET_ENTRIES) 1870 ret = compat_table_info(t->private, &repl); 1871 else 1872 ret = compat_table_info(&tinfo, &repl); 1873 if (ret) 1874 return ret; 1875 1876 if (*len != sizeof(tmp) + repl.entries_size + 1877 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) { 1878 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n", 1879 *len, tinfo.entries_size, repl.entries_size); 1880 return -EINVAL; 1881 } 1882 1883 /* userspace might not need the counters */ 1884 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters), 1885 tmp.num_counters, tinfo.nentries); 1886 if (ret) 1887 return ret; 1888 1889 pos = compat_ptr(tmp.entries); 1890 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size, 1891 compat_copy_entry_to_user, &pos, &tmp.entries_size); 1892 } 1893 1894 struct ebt_entries_buf_state { 1895 char *buf_kern_start; /* kernel buffer to copy (translated) data to */ 1896 u32 buf_kern_len; /* total size of kernel buffer */ 1897 u32 buf_kern_offset; /* amount of data copied so far */ 1898 u32 buf_user_offset; /* read position in userspace buffer */ 1899 }; 1900 1901 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz) 1902 { 1903 state->buf_kern_offset += sz; 1904 return state->buf_kern_offset >= sz ? 0 : -EINVAL; 1905 } 1906 1907 static int ebt_buf_add(struct ebt_entries_buf_state *state, 1908 void *data, unsigned int sz) 1909 { 1910 if (state->buf_kern_start == NULL) 1911 goto count_only; 1912 1913 BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len); 1914 1915 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz); 1916 1917 count_only: 1918 state->buf_user_offset += sz; 1919 return ebt_buf_count(state, sz); 1920 } 1921 1922 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz) 1923 { 1924 char *b = state->buf_kern_start; 1925 1926 BUG_ON(b && state->buf_kern_offset > state->buf_kern_len); 1927 1928 if (b != NULL && sz > 0) 1929 memset(b + state->buf_kern_offset, 0, sz); 1930 /* do not adjust ->buf_user_offset here, we added kernel-side padding */ 1931 return ebt_buf_count(state, sz); 1932 } 1933 1934 enum compat_mwt { 1935 EBT_COMPAT_MATCH, 1936 EBT_COMPAT_WATCHER, 1937 EBT_COMPAT_TARGET, 1938 }; 1939 1940 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt, 1941 enum compat_mwt compat_mwt, 1942 struct ebt_entries_buf_state *state, 1943 const unsigned char *base) 1944 { 1945 char name[EBT_FUNCTION_MAXNAMELEN]; 1946 struct xt_match *match; 1947 struct xt_target *wt; 1948 void *dst = NULL; 1949 int off, pad = 0; 1950 unsigned int size_kern, match_size = mwt->match_size; 1951 1952 strlcpy(name, mwt->u.name, sizeof(name)); 1953 1954 if (state->buf_kern_start) 1955 dst = state->buf_kern_start + state->buf_kern_offset; 1956 1957 switch (compat_mwt) { 1958 case EBT_COMPAT_MATCH: 1959 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0); 1960 if (IS_ERR(match)) 1961 return PTR_ERR(match); 1962 1963 off = ebt_compat_match_offset(match, match_size); 1964 if (dst) { 1965 if (match->compat_from_user) 1966 match->compat_from_user(dst, mwt->data); 1967 else 1968 memcpy(dst, mwt->data, match_size); 1969 } 1970 1971 size_kern = match->matchsize; 1972 if (unlikely(size_kern == -1)) 1973 size_kern = match_size; 1974 module_put(match->me); 1975 break; 1976 case EBT_COMPAT_WATCHER: /* fallthrough */ 1977 case EBT_COMPAT_TARGET: 1978 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0); 1979 if (IS_ERR(wt)) 1980 return PTR_ERR(wt); 1981 off = xt_compat_target_offset(wt); 1982 1983 if (dst) { 1984 if (wt->compat_from_user) 1985 wt->compat_from_user(dst, mwt->data); 1986 else 1987 memcpy(dst, mwt->data, match_size); 1988 } 1989 1990 size_kern = wt->targetsize; 1991 module_put(wt->me); 1992 break; 1993 1994 default: 1995 return -EINVAL; 1996 } 1997 1998 state->buf_kern_offset += match_size + off; 1999 state->buf_user_offset += match_size; 2000 pad = XT_ALIGN(size_kern) - size_kern; 2001 2002 if (pad > 0 && dst) { 2003 BUG_ON(state->buf_kern_len <= pad); 2004 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad); 2005 memset(dst + size_kern, 0, pad); 2006 } 2007 return off + match_size; 2008 } 2009 2010 /* return size of all matches, watchers or target, including necessary 2011 * alignment and padding. 2012 */ 2013 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32, 2014 unsigned int size_left, enum compat_mwt type, 2015 struct ebt_entries_buf_state *state, const void *base) 2016 { 2017 int growth = 0; 2018 char *buf; 2019 2020 if (size_left == 0) 2021 return 0; 2022 2023 buf = (char *) match32; 2024 2025 while (size_left >= sizeof(*match32)) { 2026 struct ebt_entry_match *match_kern; 2027 int ret; 2028 2029 match_kern = (struct ebt_entry_match *) state->buf_kern_start; 2030 if (match_kern) { 2031 char *tmp; 2032 tmp = state->buf_kern_start + state->buf_kern_offset; 2033 match_kern = (struct ebt_entry_match *) tmp; 2034 } 2035 ret = ebt_buf_add(state, buf, sizeof(*match32)); 2036 if (ret < 0) 2037 return ret; 2038 size_left -= sizeof(*match32); 2039 2040 /* add padding before match->data (if any) */ 2041 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize()); 2042 if (ret < 0) 2043 return ret; 2044 2045 if (match32->match_size > size_left) 2046 return -EINVAL; 2047 2048 size_left -= match32->match_size; 2049 2050 ret = compat_mtw_from_user(match32, type, state, base); 2051 if (ret < 0) 2052 return ret; 2053 2054 BUG_ON(ret < match32->match_size); 2055 growth += ret - match32->match_size; 2056 growth += ebt_compat_entry_padsize(); 2057 2058 buf += sizeof(*match32); 2059 buf += match32->match_size; 2060 2061 if (match_kern) 2062 match_kern->match_size = ret; 2063 2064 WARN_ON(type == EBT_COMPAT_TARGET && size_left); 2065 match32 = (struct compat_ebt_entry_mwt *) buf; 2066 } 2067 2068 return growth; 2069 } 2070 2071 /* called for all ebt_entry structures. */ 2072 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, 2073 unsigned int *total, 2074 struct ebt_entries_buf_state *state) 2075 { 2076 unsigned int i, j, startoff, new_offset = 0; 2077 /* stores match/watchers/targets & offset of next struct ebt_entry: */ 2078 unsigned int offsets[4]; 2079 unsigned int *offsets_update = NULL; 2080 int ret; 2081 char *buf_start; 2082 2083 if (*total < sizeof(struct ebt_entries)) 2084 return -EINVAL; 2085 2086 if (!entry->bitmask) { 2087 *total -= sizeof(struct ebt_entries); 2088 return ebt_buf_add(state, entry, sizeof(struct ebt_entries)); 2089 } 2090 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry)) 2091 return -EINVAL; 2092 2093 startoff = state->buf_user_offset; 2094 /* pull in most part of ebt_entry, it does not need to be changed. */ 2095 ret = ebt_buf_add(state, entry, 2096 offsetof(struct ebt_entry, watchers_offset)); 2097 if (ret < 0) 2098 return ret; 2099 2100 offsets[0] = sizeof(struct ebt_entry); /* matches come first */ 2101 memcpy(&offsets[1], &entry->watchers_offset, 2102 sizeof(offsets) - sizeof(offsets[0])); 2103 2104 if (state->buf_kern_start) { 2105 buf_start = state->buf_kern_start + state->buf_kern_offset; 2106 offsets_update = (unsigned int *) buf_start; 2107 } 2108 ret = ebt_buf_add(state, &offsets[1], 2109 sizeof(offsets) - sizeof(offsets[0])); 2110 if (ret < 0) 2111 return ret; 2112 buf_start = (char *) entry; 2113 /* 0: matches offset, always follows ebt_entry. 2114 * 1: watchers offset, from ebt_entry structure 2115 * 2: target offset, from ebt_entry structure 2116 * 3: next ebt_entry offset, from ebt_entry structure 2117 * 2118 * offsets are relative to beginning of struct ebt_entry (i.e., 0). 2119 */ 2120 for (i = 0, j = 1 ; j < 4 ; j++, i++) { 2121 struct compat_ebt_entry_mwt *match32; 2122 unsigned int size; 2123 char *buf = buf_start; 2124 2125 buf = buf_start + offsets[i]; 2126 if (offsets[i] > offsets[j]) 2127 return -EINVAL; 2128 2129 match32 = (struct compat_ebt_entry_mwt *) buf; 2130 size = offsets[j] - offsets[i]; 2131 ret = ebt_size_mwt(match32, size, i, state, base); 2132 if (ret < 0) 2133 return ret; 2134 new_offset += ret; 2135 if (offsets_update && new_offset) { 2136 pr_debug("change offset %d to %d\n", 2137 offsets_update[i], offsets[j] + new_offset); 2138 offsets_update[i] = offsets[j] + new_offset; 2139 } 2140 } 2141 2142 if (state->buf_kern_start == NULL) { 2143 unsigned int offset = buf_start - (char *) base; 2144 2145 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset); 2146 if (ret < 0) 2147 return ret; 2148 } 2149 2150 startoff = state->buf_user_offset - startoff; 2151 2152 BUG_ON(*total < startoff); 2153 *total -= startoff; 2154 return 0; 2155 } 2156 2157 /* repl->entries_size is the size of the ebt_entry blob in userspace. 2158 * It might need more memory when copied to a 64 bit kernel in case 2159 * userspace is 32-bit. So, first task: find out how much memory is needed. 2160 * 2161 * Called before validation is performed. 2162 */ 2163 static int compat_copy_entries(unsigned char *data, unsigned int size_user, 2164 struct ebt_entries_buf_state *state) 2165 { 2166 unsigned int size_remaining = size_user; 2167 int ret; 2168 2169 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data, 2170 &size_remaining, state); 2171 if (ret < 0) 2172 return ret; 2173 2174 WARN_ON(size_remaining); 2175 return state->buf_kern_offset; 2176 } 2177 2178 2179 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, 2180 void __user *user, unsigned int len) 2181 { 2182 struct compat_ebt_replace tmp; 2183 int i; 2184 2185 if (len < sizeof(tmp)) 2186 return -EINVAL; 2187 2188 if (copy_from_user(&tmp, user, sizeof(tmp))) 2189 return -EFAULT; 2190 2191 if (len != sizeof(tmp) + tmp.entries_size) 2192 return -EINVAL; 2193 2194 if (tmp.entries_size == 0) 2195 return -EINVAL; 2196 2197 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / 2198 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) 2199 return -ENOMEM; 2200 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) 2201 return -ENOMEM; 2202 2203 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry)); 2204 2205 /* starting with hook_entry, 32 vs. 64 bit structures are different */ 2206 for (i = 0; i < NF_BR_NUMHOOKS; i++) 2207 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]); 2208 2209 repl->num_counters = tmp.num_counters; 2210 repl->counters = compat_ptr(tmp.counters); 2211 repl->entries = compat_ptr(tmp.entries); 2212 return 0; 2213 } 2214 2215 static int compat_do_replace(struct net *net, void __user *user, 2216 unsigned int len) 2217 { 2218 int ret, i, countersize, size64; 2219 struct ebt_table_info *newinfo; 2220 struct ebt_replace tmp; 2221 struct ebt_entries_buf_state state; 2222 void *entries_tmp; 2223 2224 ret = compat_copy_ebt_replace_from_user(&tmp, user, len); 2225 if (ret) { 2226 /* try real handler in case userland supplied needed padding */ 2227 if (ret == -EINVAL && do_replace(net, user, len) == 0) 2228 ret = 0; 2229 return ret; 2230 } 2231 2232 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; 2233 newinfo = vmalloc(sizeof(*newinfo) + countersize); 2234 if (!newinfo) 2235 return -ENOMEM; 2236 2237 if (countersize) 2238 memset(newinfo->counters, 0, countersize); 2239 2240 memset(&state, 0, sizeof(state)); 2241 2242 newinfo->entries = vmalloc(tmp.entries_size); 2243 if (!newinfo->entries) { 2244 ret = -ENOMEM; 2245 goto free_newinfo; 2246 } 2247 if (copy_from_user( 2248 newinfo->entries, tmp.entries, tmp.entries_size) != 0) { 2249 ret = -EFAULT; 2250 goto free_entries; 2251 } 2252 2253 entries_tmp = newinfo->entries; 2254 2255 xt_compat_lock(NFPROTO_BRIDGE); 2256 2257 xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries); 2258 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2259 if (ret < 0) 2260 goto out_unlock; 2261 2262 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n", 2263 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset, 2264 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size)); 2265 2266 size64 = ret; 2267 newinfo->entries = vmalloc(size64); 2268 if (!newinfo->entries) { 2269 vfree(entries_tmp); 2270 ret = -ENOMEM; 2271 goto out_unlock; 2272 } 2273 2274 memset(&state, 0, sizeof(state)); 2275 state.buf_kern_start = newinfo->entries; 2276 state.buf_kern_len = size64; 2277 2278 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 2279 BUG_ON(ret < 0); /* parses same data again */ 2280 2281 vfree(entries_tmp); 2282 tmp.entries_size = size64; 2283 2284 for (i = 0; i < NF_BR_NUMHOOKS; i++) { 2285 char __user *usrptr; 2286 if (tmp.hook_entry[i]) { 2287 unsigned int delta; 2288 usrptr = (char __user *) tmp.hook_entry[i]; 2289 delta = usrptr - tmp.entries; 2290 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta); 2291 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr; 2292 } 2293 } 2294 2295 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2296 xt_compat_unlock(NFPROTO_BRIDGE); 2297 2298 ret = do_replace_finish(net, &tmp, newinfo); 2299 if (ret == 0) 2300 return ret; 2301 free_entries: 2302 vfree(newinfo->entries); 2303 free_newinfo: 2304 vfree(newinfo); 2305 return ret; 2306 out_unlock: 2307 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2308 xt_compat_unlock(NFPROTO_BRIDGE); 2309 goto free_entries; 2310 } 2311 2312 static int compat_update_counters(struct net *net, void __user *user, 2313 unsigned int len) 2314 { 2315 struct compat_ebt_replace hlp; 2316 2317 if (copy_from_user(&hlp, user, sizeof(hlp))) 2318 return -EFAULT; 2319 2320 /* try real handler in case userland supplied needed padding */ 2321 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) 2322 return update_counters(net, user, len); 2323 2324 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters), 2325 hlp.num_counters, user, len); 2326 } 2327 2328 static int compat_do_ebt_set_ctl(struct sock *sk, 2329 int cmd, void __user *user, unsigned int len) 2330 { 2331 int ret; 2332 struct net *net = sock_net(sk); 2333 2334 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2335 return -EPERM; 2336 2337 switch (cmd) { 2338 case EBT_SO_SET_ENTRIES: 2339 ret = compat_do_replace(net, user, len); 2340 break; 2341 case EBT_SO_SET_COUNTERS: 2342 ret = compat_update_counters(net, user, len); 2343 break; 2344 default: 2345 ret = -EINVAL; 2346 } 2347 return ret; 2348 } 2349 2350 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd, 2351 void __user *user, int *len) 2352 { 2353 int ret; 2354 struct compat_ebt_replace tmp; 2355 struct ebt_table *t; 2356 struct net *net = sock_net(sk); 2357 2358 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2359 return -EPERM; 2360 2361 /* try real handler in case userland supplied needed padding */ 2362 if ((cmd == EBT_SO_GET_INFO || 2363 cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp)) 2364 return do_ebt_get_ctl(sk, cmd, user, len); 2365 2366 if (copy_from_user(&tmp, user, sizeof(tmp))) 2367 return -EFAULT; 2368 2369 tmp.name[sizeof(tmp.name) - 1] = '\0'; 2370 2371 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); 2372 if (!t) 2373 return ret; 2374 2375 xt_compat_lock(NFPROTO_BRIDGE); 2376 switch (cmd) { 2377 case EBT_SO_GET_INFO: 2378 tmp.nentries = t->private->nentries; 2379 ret = compat_table_info(t->private, &tmp); 2380 if (ret) 2381 goto out; 2382 tmp.valid_hooks = t->valid_hooks; 2383 2384 if (copy_to_user(user, &tmp, *len) != 0) { 2385 ret = -EFAULT; 2386 break; 2387 } 2388 ret = 0; 2389 break; 2390 case EBT_SO_GET_INIT_INFO: 2391 tmp.nentries = t->table->nentries; 2392 tmp.entries_size = t->table->entries_size; 2393 tmp.valid_hooks = t->table->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_ENTRIES: 2402 case EBT_SO_GET_INIT_ENTRIES: 2403 /* try real handler first in case of userland-side padding. 2404 * in case we are dealing with an 'ordinary' 32 bit binary 2405 * without 64bit compatibility padding, this will fail right 2406 * after copy_from_user when the *len argument is validated. 2407 * 2408 * the compat_ variant needs to do one pass over the kernel 2409 * data set to adjust for size differences before it the check. 2410 */ 2411 if (copy_everything_to_user(t, user, len, cmd) == 0) 2412 ret = 0; 2413 else 2414 ret = compat_copy_everything_to_user(t, user, len, cmd); 2415 break; 2416 default: 2417 ret = -EINVAL; 2418 } 2419 out: 2420 xt_compat_flush_offsets(NFPROTO_BRIDGE); 2421 xt_compat_unlock(NFPROTO_BRIDGE); 2422 mutex_unlock(&ebt_mutex); 2423 return ret; 2424 } 2425 #endif 2426 2427 static struct nf_sockopt_ops ebt_sockopts = { 2428 .pf = PF_INET, 2429 .set_optmin = EBT_BASE_CTL, 2430 .set_optmax = EBT_SO_SET_MAX + 1, 2431 .set = do_ebt_set_ctl, 2432 #ifdef CONFIG_COMPAT 2433 .compat_set = compat_do_ebt_set_ctl, 2434 #endif 2435 .get_optmin = EBT_BASE_CTL, 2436 .get_optmax = EBT_SO_GET_MAX + 1, 2437 .get = do_ebt_get_ctl, 2438 #ifdef CONFIG_COMPAT 2439 .compat_get = compat_do_ebt_get_ctl, 2440 #endif 2441 .owner = THIS_MODULE, 2442 }; 2443 2444 static int __init ebtables_init(void) 2445 { 2446 int ret; 2447 2448 ret = xt_register_target(&ebt_standard_target); 2449 if (ret < 0) 2450 return ret; 2451 ret = nf_register_sockopt(&ebt_sockopts); 2452 if (ret < 0) { 2453 xt_unregister_target(&ebt_standard_target); 2454 return ret; 2455 } 2456 2457 printk(KERN_INFO "Ebtables v2.0 registered\n"); 2458 return 0; 2459 } 2460 2461 static void __exit ebtables_fini(void) 2462 { 2463 nf_unregister_sockopt(&ebt_sockopts); 2464 xt_unregister_target(&ebt_standard_target); 2465 printk(KERN_INFO "Ebtables v2.0 unregistered\n"); 2466 } 2467 2468 EXPORT_SYMBOL(ebt_register_table); 2469 EXPORT_SYMBOL(ebt_unregister_table); 2470 EXPORT_SYMBOL(ebt_do_table); 2471 module_init(ebtables_init); 2472 module_exit(ebtables_fini); 2473 MODULE_LICENSE("GPL"); 2474