1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  ebtables
   4 *
   5 *  Author:
   6 *  Bart De Schuymer		<bdschuym@pandora.be>
   7 *
   8 *  ebtables.c,v 2.0, July, 2002
   9 *
  10 *  This code is strongly inspired by the iptables code which is
  11 *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 
 
 
 
 
  12 */
  13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14#include <linux/kmod.h>
  15#include <linux/module.h>
  16#include <linux/vmalloc.h>
  17#include <linux/netfilter/x_tables.h>
  18#include <linux/netfilter_bridge/ebtables.h>
  19#include <linux/spinlock.h>
  20#include <linux/mutex.h>
  21#include <linux/slab.h>
  22#include <linux/uaccess.h>
  23#include <linux/smp.h>
  24#include <linux/cpumask.h>
  25#include <linux/audit.h>
  26#include <net/sock.h>
  27#include <net/netns/generic.h>
  28/* needed for logical [in,out]-dev filtering */
  29#include "../br_private.h"
  30
 
 
 
 
  31/* Each cpu has its own set of counters, so there is no need for write_lock in
  32 * the softirq
  33 * For reading or updating the counters, the user context needs to
  34 * get a write_lock
  35 */
  36
  37/* The size of each set of counters is altered to get cache alignment */
  38#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  39#define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  40#define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  41				 COUNTER_OFFSET(n) * cpu))
  42
  43struct ebt_pernet {
  44	struct list_head tables;
  45};
  46
  47struct ebt_template {
  48	struct list_head list;
  49	char name[EBT_TABLE_MAXNAMELEN];
  50	struct module *owner;
  51	/* called when table is needed in the given netns */
  52	int (*table_init)(struct net *net);
  53};
  54
  55static unsigned int ebt_pernet_id __read_mostly;
  56static LIST_HEAD(template_tables);
  57static DEFINE_MUTEX(ebt_mutex);
  58
  59#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  60static void ebt_standard_compat_from_user(void *dst, const void *src)
  61{
  62	int v = *(compat_int_t *)src;
  63
  64	if (v >= 0)
  65		v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  66	memcpy(dst, &v, sizeof(v));
  67}
  68
  69static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  70{
  71	compat_int_t cv = *(int *)src;
  72
  73	if (cv >= 0)
  74		cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  75	return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  76}
  77#endif
  78
  79
  80static struct xt_target ebt_standard_target = {
  81	.name       = "standard",
  82	.revision   = 0,
  83	.family     = NFPROTO_BRIDGE,
  84	.targetsize = sizeof(int),
  85#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
  86	.compatsize = sizeof(compat_int_t),
  87	.compat_from_user = ebt_standard_compat_from_user,
  88	.compat_to_user =  ebt_standard_compat_to_user,
  89#endif
  90};
  91
  92static inline int
  93ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  94	       struct xt_action_param *par)
  95{
  96	par->target   = w->u.watcher;
  97	par->targinfo = w->data;
  98	w->u.watcher->target(skb, par);
  99	/* watchers don't give a verdict */
 100	return 0;
 101}
 102
 103static inline int
 104ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
 105	     struct xt_action_param *par)
 106{
 107	par->match     = m->u.match;
 108	par->matchinfo = m->data;
 109	return !m->u.match->match(skb, par);
 110}
 111
 112static inline int
 113ebt_dev_check(const char *entry, const struct net_device *device)
 114{
 115	int i = 0;
 116	const char *devname;
 117
 118	if (*entry == '\0')
 119		return 0;
 120	if (!device)
 121		return 1;
 122	devname = device->name;
 123	/* 1 is the wildcard token */
 124	while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 125		i++;
 126	return devname[i] != entry[i] && entry[i] != 1;
 127}
 128
 129/* process standard matches */
 130static inline int
 131ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 132		const struct net_device *in, const struct net_device *out)
 133{
 134	const struct ethhdr *h = eth_hdr(skb);
 135	const struct net_bridge_port *p;
 136	__be16 ethproto;
 137
 138	if (skb_vlan_tag_present(skb))
 139		ethproto = htons(ETH_P_8021Q);
 140	else
 141		ethproto = h->h_proto;
 142
 143	if (e->bitmask & EBT_802_3) {
 144		if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 145			return 1;
 146	} else if (!(e->bitmask & EBT_NOPROTO) &&
 147		   NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 148		return 1;
 149
 150	if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 151		return 1;
 152	if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 153		return 1;
 154	/* rcu_read_lock()ed by nf_hook_thresh */
 155	if (in && (p = br_port_get_rcu(in)) != NULL &&
 156	    NF_INVF(e, EBT_ILOGICALIN,
 157		    ebt_dev_check(e->logical_in, p->br->dev)))
 158		return 1;
 159	if (out && (p = br_port_get_rcu(out)) != NULL &&
 160	    NF_INVF(e, EBT_ILOGICALOUT,
 161		    ebt_dev_check(e->logical_out, p->br->dev)))
 162		return 1;
 163
 164	if (e->bitmask & EBT_SOURCEMAC) {
 165		if (NF_INVF(e, EBT_ISOURCE,
 166			    !ether_addr_equal_masked(h->h_source, e->sourcemac,
 167						     e->sourcemsk)))
 168			return 1;
 169	}
 170	if (e->bitmask & EBT_DESTMAC) {
 171		if (NF_INVF(e, EBT_IDEST,
 172			    !ether_addr_equal_masked(h->h_dest, e->destmac,
 173						     e->destmsk)))
 174			return 1;
 175	}
 176	return 0;
 177}
 178
 179static inline
 180struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 181{
 182	return (void *)entry + entry->next_offset;
 183}
 184
 185static inline const struct ebt_entry_target *
 186ebt_get_target_c(const struct ebt_entry *e)
 187{
 188	return ebt_get_target((struct ebt_entry *)e);
 189}
 190
 191/* Do some firewalling */
 192unsigned int ebt_do_table(void *priv, struct sk_buff *skb,
 193			  const struct nf_hook_state *state)
 
 194{
 195	struct ebt_table *table = priv;
 196	unsigned int hook = state->hook;
 197	int i, nentries;
 198	struct ebt_entry *point;
 199	struct ebt_counter *counter_base, *cb_base;
 200	const struct ebt_entry_target *t;
 201	int verdict, sp = 0;
 202	struct ebt_chainstack *cs;
 203	struct ebt_entries *chaininfo;
 204	const char *base;
 205	const struct ebt_table_info *private;
 206	struct xt_action_param acpar;
 207
 208	acpar.state   = state;
 209	acpar.hotdrop = false;
 210
 211	read_lock_bh(&table->lock);
 212	private = table->private;
 213	cb_base = COUNTER_BASE(private->counters, private->nentries,
 214	   smp_processor_id());
 215	if (private->chainstack)
 216		cs = private->chainstack[smp_processor_id()];
 217	else
 218		cs = NULL;
 219	chaininfo = private->hook_entry[hook];
 220	nentries = private->hook_entry[hook]->nentries;
 221	point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 222	counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 223	/* base for chain jumps */
 224	base = private->entries;
 225	i = 0;
 226	while (i < nentries) {
 227		if (ebt_basic_match(point, skb, state->in, state->out))
 228			goto letscontinue;
 229
 230		if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 231			goto letscontinue;
 232		if (acpar.hotdrop) {
 233			read_unlock_bh(&table->lock);
 234			return NF_DROP;
 235		}
 236
 237		ADD_COUNTER(*(counter_base + i), skb->len, 1);
 238
 239		/* these should only watch: not modify, nor tell us
 240		 * what to do with the packet
 241		 */
 242		EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 243
 244		t = ebt_get_target_c(point);
 
 245		/* standard target */
 246		if (!t->u.target->target)
 247			verdict = ((struct ebt_standard_target *)t)->verdict;
 248		else {
 249			acpar.target   = t->u.target;
 250			acpar.targinfo = t->data;
 251			verdict = t->u.target->target(skb, &acpar);
 252		}
 253		if (verdict == EBT_ACCEPT) {
 254			read_unlock_bh(&table->lock);
 255			return NF_ACCEPT;
 256		}
 257		if (verdict == EBT_DROP) {
 258			read_unlock_bh(&table->lock);
 259			return NF_DROP;
 260		}
 261		if (verdict == EBT_RETURN) {
 262letsreturn:
 263			if (WARN(sp == 0, "RETURN on base chain")) {
 264				/* act like this is EBT_CONTINUE */
 265				goto letscontinue;
 266			}
 267
 268			sp--;
 269			/* put all the local variables right */
 270			i = cs[sp].n;
 271			chaininfo = cs[sp].chaininfo;
 272			nentries = chaininfo->nentries;
 273			point = cs[sp].e;
 274			counter_base = cb_base +
 275			   chaininfo->counter_offset;
 276			continue;
 277		}
 278		if (verdict == EBT_CONTINUE)
 279			goto letscontinue;
 280
 281		if (WARN(verdict < 0, "bogus standard verdict\n")) {
 282			read_unlock_bh(&table->lock);
 283			return NF_DROP;
 284		}
 285
 286		/* jump to a udc */
 287		cs[sp].n = i + 1;
 288		cs[sp].chaininfo = chaininfo;
 289		cs[sp].e = ebt_next_entry(point);
 290		i = 0;
 291		chaininfo = (struct ebt_entries *) (base + verdict);
 292
 293		if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 294			read_unlock_bh(&table->lock);
 295			return NF_DROP;
 296		}
 297
 298		nentries = chaininfo->nentries;
 299		point = (struct ebt_entry *)chaininfo->data;
 300		counter_base = cb_base + chaininfo->counter_offset;
 301		sp++;
 302		continue;
 303letscontinue:
 304		point = ebt_next_entry(point);
 305		i++;
 306	}
 307
 308	/* I actually like this :) */
 309	if (chaininfo->policy == EBT_RETURN)
 310		goto letsreturn;
 311	if (chaininfo->policy == EBT_ACCEPT) {
 312		read_unlock_bh(&table->lock);
 313		return NF_ACCEPT;
 314	}
 315	read_unlock_bh(&table->lock);
 316	return NF_DROP;
 317}
 318
 319/* If it succeeds, returns element and locks mutex */
 320static inline void *
 321find_inlist_lock_noload(struct net *net, const char *name, int *error,
 322			struct mutex *mutex)
 323{
 324	struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
 325	struct ebt_template *tmpl;
 326	struct ebt_table *table;
 
 327
 328	mutex_lock(mutex);
 329	list_for_each_entry(table, &ebt_net->tables, list) {
 330		if (strcmp(table->name, name) == 0)
 331			return table;
 332	}
 333
 334	list_for_each_entry(tmpl, &template_tables, list) {
 335		if (strcmp(name, tmpl->name) == 0) {
 336			struct module *owner = tmpl->owner;
 337
 338			if (!try_module_get(owner))
 339				goto out;
 340
 341			mutex_unlock(mutex);
 342
 343			*error = tmpl->table_init(net);
 344			if (*error) {
 345				module_put(owner);
 346				return NULL;
 347			}
 348
 349			mutex_lock(mutex);
 350			module_put(owner);
 351			break;
 352		}
 353	}
 354
 355	list_for_each_entry(table, &ebt_net->tables, list) {
 356		if (strcmp(table->name, name) == 0)
 357			return table;
 358	}
 359
 360out:
 361	*error = -ENOENT;
 362	mutex_unlock(mutex);
 363	return NULL;
 364}
 365
 366static void *
 367find_inlist_lock(struct net *net, const char *name, const char *prefix,
 368		 int *error, struct mutex *mutex)
 369{
 370	return try_then_request_module(
 371			find_inlist_lock_noload(net, name, error, mutex),
 372			"%s%s", prefix, name);
 373}
 374
 375static inline struct ebt_table *
 376find_table_lock(struct net *net, const char *name, int *error,
 377		struct mutex *mutex)
 378{
 379	return find_inlist_lock(net, name, "ebtable_", error, mutex);
 
 380}
 381
 382static inline void ebt_free_table_info(struct ebt_table_info *info)
 383{
 384	int i;
 385
 386	if (info->chainstack) {
 387		for_each_possible_cpu(i)
 388			vfree(info->chainstack[i]);
 389		vfree(info->chainstack);
 390	}
 391}
 392static inline int
 393ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 394		unsigned int *cnt)
 395{
 396	const struct ebt_entry *e = par->entryinfo;
 397	struct xt_match *match;
 398	size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 399	int ret;
 400
 401	if (left < sizeof(struct ebt_entry_match) ||
 402	    left - sizeof(struct ebt_entry_match) < m->match_size)
 403		return -EINVAL;
 404
 405	match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 406	if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 407		if (!IS_ERR(match))
 408			module_put(match->me);
 409		request_module("ebt_%s", m->u.name);
 410		match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 411	}
 412	if (IS_ERR(match))
 413		return PTR_ERR(match);
 414	m->u.match = match;
 415
 416	par->match     = match;
 417	par->matchinfo = m->data;
 418	ret = xt_check_match(par, m->match_size,
 419	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 420	if (ret < 0) {
 421		module_put(match->me);
 422		return ret;
 423	}
 424
 425	(*cnt)++;
 426	return 0;
 427}
 428
 429static inline int
 430ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 431		  unsigned int *cnt)
 432{
 433	const struct ebt_entry *e = par->entryinfo;
 434	struct xt_target *watcher;
 435	size_t left = ((char *)e + e->target_offset) - (char *)w;
 436	int ret;
 437
 438	if (left < sizeof(struct ebt_entry_watcher) ||
 439	   left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 440		return -EINVAL;
 441
 442	watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 443	if (IS_ERR(watcher))
 444		return PTR_ERR(watcher);
 445
 446	if (watcher->family != NFPROTO_BRIDGE) {
 447		module_put(watcher->me);
 448		return -ENOENT;
 449	}
 450
 451	w->u.watcher = watcher;
 452
 453	par->target   = watcher;
 454	par->targinfo = w->data;
 455	ret = xt_check_target(par, w->watcher_size,
 456	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 457	if (ret < 0) {
 458		module_put(watcher->me);
 459		return ret;
 460	}
 461
 462	(*cnt)++;
 463	return 0;
 464}
 465
 466static int ebt_verify_pointers(const struct ebt_replace *repl,
 467			       struct ebt_table_info *newinfo)
 468{
 469	unsigned int limit = repl->entries_size;
 470	unsigned int valid_hooks = repl->valid_hooks;
 471	unsigned int offset = 0;
 472	int i;
 473
 474	for (i = 0; i < NF_BR_NUMHOOKS; i++)
 475		newinfo->hook_entry[i] = NULL;
 476
 477	newinfo->entries_size = repl->entries_size;
 478	newinfo->nentries = repl->nentries;
 479
 480	while (offset < limit) {
 481		size_t left = limit - offset;
 482		struct ebt_entry *e = (void *)newinfo->entries + offset;
 483
 484		if (left < sizeof(unsigned int))
 485			break;
 486
 487		for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 488			if ((valid_hooks & (1 << i)) == 0)
 489				continue;
 490			if ((char __user *)repl->hook_entry[i] ==
 491			     repl->entries + offset)
 492				break;
 493		}
 494
 495		if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 496			if (e->bitmask != 0) {
 497				/* we make userspace set this right,
 498				 * so there is no misunderstanding
 499				 */
 
 
 500				return -EINVAL;
 501			}
 502			if (i != NF_BR_NUMHOOKS)
 503				newinfo->hook_entry[i] = (struct ebt_entries *)e;
 504			if (left < sizeof(struct ebt_entries))
 505				break;
 506			offset += sizeof(struct ebt_entries);
 507		} else {
 508			if (left < sizeof(struct ebt_entry))
 509				break;
 510			if (left < e->next_offset)
 511				break;
 512			if (e->next_offset < sizeof(struct ebt_entry))
 513				return -EINVAL;
 514			offset += e->next_offset;
 515		}
 516	}
 517	if (offset != limit)
 
 518		return -EINVAL;
 
 519
 520	/* check if all valid hooks have a chain */
 521	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 522		if (!newinfo->hook_entry[i] &&
 523		   (valid_hooks & (1 << i)))
 
 524			return -EINVAL;
 
 525	}
 526	return 0;
 527}
 528
 529/* this one is very careful, as it is the first function
 530 * to parse the userspace data
 531 */
 532static inline int
 533ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 534			       const struct ebt_table_info *newinfo,
 535			       unsigned int *n, unsigned int *cnt,
 536			       unsigned int *totalcnt, unsigned int *udc_cnt)
 537{
 538	int i;
 539
 540	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 541		if ((void *)e == (void *)newinfo->hook_entry[i])
 542			break;
 543	}
 544	/* beginning of a new chain
 545	 * if i == NF_BR_NUMHOOKS it must be a user defined chain
 546	 */
 547	if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 548		/* this checks if the previous chain has as many entries
 549		 * as it said it has
 550		 */
 551		if (*n != *cnt)
 
 
 552			return -EINVAL;
 553
 554		if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 555		   ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 556			/* only RETURN from udc */
 557			if (i != NF_BR_NUMHOOKS ||
 558			   ((struct ebt_entries *)e)->policy != EBT_RETURN)
 
 559				return -EINVAL;
 
 560		}
 561		if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 562			(*udc_cnt)++;
 563		if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
 
 564			return -EINVAL;
 
 565		*n = ((struct ebt_entries *)e)->nentries;
 566		*cnt = 0;
 567		return 0;
 568	}
 569	/* a plain old entry, heh */
 570	if (sizeof(struct ebt_entry) > e->watchers_offset ||
 571	   e->watchers_offset > e->target_offset ||
 572	   e->target_offset >= e->next_offset)
 
 573		return -EINVAL;
 574
 575	/* this is not checked anywhere else */
 576	if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
 
 577		return -EINVAL;
 578
 579	(*cnt)++;
 580	(*totalcnt)++;
 581	return 0;
 582}
 583
 584struct ebt_cl_stack {
 585	struct ebt_chainstack cs;
 586	int from;
 587	unsigned int hookmask;
 588};
 589
 590/* We need these positions to check that the jumps to a different part of the
 591 * entries is a jump to the beginning of a new chain.
 592 */
 593static inline int
 594ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 595		      unsigned int *n, struct ebt_cl_stack *udc)
 596{
 597	int i;
 598
 599	/* we're only interested in chain starts */
 600	if (e->bitmask)
 601		return 0;
 602	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 603		if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 604			break;
 605	}
 606	/* only care about udc */
 607	if (i != NF_BR_NUMHOOKS)
 608		return 0;
 609
 610	udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 611	/* these initialisations are depended on later in check_chainloops() */
 612	udc[*n].cs.n = 0;
 613	udc[*n].hookmask = 0;
 614
 615	(*n)++;
 616	return 0;
 617}
 618
 619static inline int
 620ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 621{
 622	struct xt_mtdtor_param par;
 623
 624	if (i && (*i)-- == 0)
 625		return 1;
 626
 627	par.net       = net;
 628	par.match     = m->u.match;
 629	par.matchinfo = m->data;
 630	par.family    = NFPROTO_BRIDGE;
 631	if (par.match->destroy != NULL)
 632		par.match->destroy(&par);
 633	module_put(par.match->me);
 634	return 0;
 635}
 636
 637static inline int
 638ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 639{
 640	struct xt_tgdtor_param par;
 641
 642	if (i && (*i)-- == 0)
 643		return 1;
 644
 645	par.net      = net;
 646	par.target   = w->u.watcher;
 647	par.targinfo = w->data;
 648	par.family   = NFPROTO_BRIDGE;
 649	if (par.target->destroy != NULL)
 650		par.target->destroy(&par);
 651	module_put(par.target->me);
 652	return 0;
 653}
 654
 655static inline int
 656ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 657{
 658	struct xt_tgdtor_param par;
 659	struct ebt_entry_target *t;
 660
 661	if (e->bitmask == 0)
 662		return 0;
 663	/* we're done */
 664	if (cnt && (*cnt)-- == 0)
 665		return 1;
 666	EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 667	EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 668	t = ebt_get_target(e);
 669
 670	par.net      = net;
 671	par.target   = t->u.target;
 672	par.targinfo = t->data;
 673	par.family   = NFPROTO_BRIDGE;
 674	if (par.target->destroy != NULL)
 675		par.target->destroy(&par);
 676	module_put(par.target->me);
 677	return 0;
 678}
 679
 680static inline int
 681ebt_check_entry(struct ebt_entry *e, struct net *net,
 682		const struct ebt_table_info *newinfo,
 683		const char *name, unsigned int *cnt,
 684		struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 685{
 686	struct ebt_entry_target *t;
 687	struct xt_target *target;
 688	unsigned int i, j, hook = 0, hookmask = 0;
 689	size_t gap;
 690	int ret;
 691	struct xt_mtchk_param mtpar;
 692	struct xt_tgchk_param tgpar;
 693
 694	/* don't mess with the struct ebt_entries */
 695	if (e->bitmask == 0)
 696		return 0;
 697
 698	if (e->bitmask & ~EBT_F_MASK)
 
 699		return -EINVAL;
 700
 701	if (e->invflags & ~EBT_INV_MASK)
 
 702		return -EINVAL;
 703
 704	if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
 
 705		return -EINVAL;
 706
 707	/* what hook do we belong to? */
 708	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 709		if (!newinfo->hook_entry[i])
 710			continue;
 711		if ((char *)newinfo->hook_entry[i] < (char *)e)
 712			hook = i;
 713		else
 714			break;
 715	}
 716	/* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 717	 * a base chain
 718	 */
 719	if (i < NF_BR_NUMHOOKS)
 720		hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 721	else {
 722		for (i = 0; i < udc_cnt; i++)
 723			if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 724				break;
 725		if (i == 0)
 726			hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 727		else
 728			hookmask = cl_s[i - 1].hookmask;
 729	}
 730	i = 0;
 731
 732	memset(&mtpar, 0, sizeof(mtpar));
 733	memset(&tgpar, 0, sizeof(tgpar));
 734	mtpar.net	= tgpar.net       = net;
 735	mtpar.table     = tgpar.table     = name;
 736	mtpar.entryinfo = tgpar.entryinfo = e;
 737	mtpar.hook_mask = tgpar.hook_mask = hookmask;
 738	mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 739	ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 740	if (ret != 0)
 741		goto cleanup_matches;
 742	j = 0;
 743	ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 744	if (ret != 0)
 745		goto cleanup_watchers;
 746	t = ebt_get_target(e);
 747	gap = e->next_offset - e->target_offset;
 748
 749	target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 750	if (IS_ERR(target)) {
 751		ret = PTR_ERR(target);
 752		goto cleanup_watchers;
 753	}
 754
 755	/* Reject UNSPEC, xtables verdicts/return values are incompatible */
 756	if (target->family != NFPROTO_BRIDGE) {
 757		module_put(target->me);
 758		ret = -ENOENT;
 759		goto cleanup_watchers;
 760	}
 761
 762	t->u.target = target;
 763	if (t->u.target == &ebt_standard_target) {
 764		if (gap < sizeof(struct ebt_standard_target)) {
 
 765			ret = -EFAULT;
 766			goto cleanup_watchers;
 767		}
 768		if (((struct ebt_standard_target *)t)->verdict <
 769		   -NUM_STANDARD_TARGETS) {
 
 770			ret = -EFAULT;
 771			goto cleanup_watchers;
 772		}
 773	} else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 774		module_put(t->u.target->me);
 775		ret = -EFAULT;
 776		goto cleanup_watchers;
 777	}
 778
 779	tgpar.target   = target;
 780	tgpar.targinfo = t->data;
 781	ret = xt_check_target(&tgpar, t->target_size,
 782	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 783	if (ret < 0) {
 784		module_put(target->me);
 785		goto cleanup_watchers;
 786	}
 787	(*cnt)++;
 788	return 0;
 789cleanup_watchers:
 790	EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 791cleanup_matches:
 792	EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 793	return ret;
 794}
 795
 796/* checks for loops and sets the hook mask for udc
 797 * the hook mask for udc tells us from which base chains the udc can be
 798 * accessed. This mask is a parameter to the check() functions of the extensions
 799 */
 800static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 801			    unsigned int udc_cnt, unsigned int hooknr, char *base)
 802{
 803	int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 804	const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 805	const struct ebt_entry_target *t;
 806
 807	while (pos < nentries || chain_nr != -1) {
 808		/* end of udc, go back one 'recursion' step */
 809		if (pos == nentries) {
 810			/* put back values of the time when this chain was called */
 811			e = cl_s[chain_nr].cs.e;
 812			if (cl_s[chain_nr].from != -1)
 813				nentries =
 814				cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 815			else
 816				nentries = chain->nentries;
 817			pos = cl_s[chain_nr].cs.n;
 818			/* make sure we won't see a loop that isn't one */
 819			cl_s[chain_nr].cs.n = 0;
 820			chain_nr = cl_s[chain_nr].from;
 821			if (pos == nentries)
 822				continue;
 823		}
 824		t = ebt_get_target_c(e);
 
 825		if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 826			goto letscontinue;
 827		if (e->target_offset + sizeof(struct ebt_standard_target) >
 828		   e->next_offset)
 
 829			return -1;
 830
 831		verdict = ((struct ebt_standard_target *)t)->verdict;
 832		if (verdict >= 0) { /* jump to another chain */
 833			struct ebt_entries *hlp2 =
 834			   (struct ebt_entries *)(base + verdict);
 835			for (i = 0; i < udc_cnt; i++)
 836				if (hlp2 == cl_s[i].cs.chaininfo)
 837					break;
 838			/* bad destination or loop */
 839			if (i == udc_cnt)
 
 840				return -1;
 841
 842			if (cl_s[i].cs.n)
 
 843				return -1;
 844
 845			if (cl_s[i].hookmask & (1 << hooknr))
 846				goto letscontinue;
 847			/* this can't be 0, so the loop test is correct */
 848			cl_s[i].cs.n = pos + 1;
 849			pos = 0;
 850			cl_s[i].cs.e = ebt_next_entry(e);
 851			e = (struct ebt_entry *)(hlp2->data);
 852			nentries = hlp2->nentries;
 853			cl_s[i].from = chain_nr;
 854			chain_nr = i;
 855			/* this udc is accessible from the base chain for hooknr */
 856			cl_s[i].hookmask |= (1 << hooknr);
 857			continue;
 858		}
 859letscontinue:
 860		e = ebt_next_entry(e);
 861		pos++;
 862	}
 863	return 0;
 864}
 865
 866/* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 867static int translate_table(struct net *net, const char *name,
 868			   struct ebt_table_info *newinfo)
 869{
 870	unsigned int i, j, k, udc_cnt;
 871	int ret;
 872	struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 873
 874	i = 0;
 875	while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 876		i++;
 877	if (i == NF_BR_NUMHOOKS)
 
 878		return -EINVAL;
 879
 880	if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
 
 881		return -EINVAL;
 882
 883	/* make sure chains are ordered after each other in same order
 884	 * as their corresponding hooks
 885	 */
 886	for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 887		if (!newinfo->hook_entry[j])
 888			continue;
 889		if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
 
 890			return -EINVAL;
 891
 892		i = j;
 893	}
 894
 895	/* do some early checkings and initialize some things */
 896	i = 0; /* holds the expected nr. of entries for the chain */
 897	j = 0; /* holds the up to now counted entries for the chain */
 898	k = 0; /* holds the total nr. of entries, should equal
 899		* newinfo->nentries afterwards
 900		*/
 901	udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 902	ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 903	   ebt_check_entry_size_and_hooks, newinfo,
 904	   &i, &j, &k, &udc_cnt);
 905
 906	if (ret != 0)
 907		return ret;
 908
 909	if (i != j)
 
 
 910		return -EINVAL;
 911
 912	if (k != newinfo->nentries)
 
 913		return -EINVAL;
 
 914
 915	/* get the location of the udc, put them in an array
 916	 * while we're at it, allocate the chainstack
 917	 */
 918	if (udc_cnt) {
 919		/* this will get free'd in do_replace()/ebt_register_table()
 920		 * if an error occurs
 921		 */
 922		newinfo->chainstack =
 923			vmalloc(array_size(nr_cpu_ids,
 924					   sizeof(*(newinfo->chainstack))));
 925		if (!newinfo->chainstack)
 926			return -ENOMEM;
 927		for_each_possible_cpu(i) {
 928			newinfo->chainstack[i] =
 929			  vmalloc_node(array_size(udc_cnt,
 930					  sizeof(*(newinfo->chainstack[0]))),
 931				       cpu_to_node(i));
 932			if (!newinfo->chainstack[i]) {
 933				while (i)
 934					vfree(newinfo->chainstack[--i]);
 935				vfree(newinfo->chainstack);
 936				newinfo->chainstack = NULL;
 937				return -ENOMEM;
 938			}
 939		}
 940
 941		cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 942		if (!cl_s)
 943			return -ENOMEM;
 944		i = 0; /* the i'th udc */
 945		EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 946		   ebt_get_udc_positions, newinfo, &i, cl_s);
 947		/* sanity check */
 948		if (i != udc_cnt) {
 
 949			vfree(cl_s);
 950			return -EFAULT;
 951		}
 952	}
 953
 954	/* Check for loops */
 955	for (i = 0; i < NF_BR_NUMHOOKS; i++)
 956		if (newinfo->hook_entry[i])
 957			if (check_chainloops(newinfo->hook_entry[i],
 958			   cl_s, udc_cnt, i, newinfo->entries)) {
 959				vfree(cl_s);
 960				return -EINVAL;
 961			}
 962
 963	/* we now know the following (along with E=mc²):
 964	 *  - the nr of entries in each chain is right
 965	 *  - the size of the allocated space is right
 966	 *  - all valid hooks have a corresponding chain
 967	 *  - there are no loops
 968	 *  - wrong data can still be on the level of a single entry
 969	 *  - could be there are jumps to places that are not the
 970	 *    beginning of a chain. This can only occur in chains that
 971	 *    are not accessible from any base chains, so we don't care.
 972	 */
 973
 974	/* used to know what we need to clean up if something goes wrong */
 975	i = 0;
 976	ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 977	   ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 978	if (ret != 0) {
 979		EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 980				  ebt_cleanup_entry, net, &i);
 981	}
 982	vfree(cl_s);
 983	return ret;
 984}
 985
 986/* called under write_lock */
 987static void get_counters(const struct ebt_counter *oldcounters,
 988			 struct ebt_counter *counters, unsigned int nentries)
 989{
 990	int i, cpu;
 991	struct ebt_counter *counter_base;
 992
 993	/* counters of cpu 0 */
 994	memcpy(counters, oldcounters,
 995	       sizeof(struct ebt_counter) * nentries);
 996
 997	/* add other counters to those of cpu 0 */
 998	for_each_possible_cpu(cpu) {
 999		if (cpu == 0)
1000			continue;
1001		counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
1002		for (i = 0; i < nentries; i++)
1003			ADD_COUNTER(counters[i], counter_base[i].bcnt,
1004				    counter_base[i].pcnt);
1005	}
1006}
1007
1008static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1009			      struct ebt_table_info *newinfo)
1010{
1011	int ret;
1012	struct ebt_counter *counterstmp = NULL;
1013	/* used to be able to unlock earlier */
1014	struct ebt_table_info *table;
1015	struct ebt_table *t;
1016
1017	/* the user wants counters back
1018	 * the check on the size is done later, when we have the lock
1019	 */
1020	if (repl->num_counters) {
1021		unsigned long size = repl->num_counters * sizeof(*counterstmp);
1022		counterstmp = vmalloc(size);
1023		if (!counterstmp)
1024			return -ENOMEM;
1025	}
1026
1027	newinfo->chainstack = NULL;
1028	ret = ebt_verify_pointers(repl, newinfo);
1029	if (ret != 0)
1030		goto free_counterstmp;
1031
1032	ret = translate_table(net, repl->name, newinfo);
1033
1034	if (ret != 0)
1035		goto free_counterstmp;
1036
1037	t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1038	if (!t) {
1039		ret = -ENOENT;
1040		goto free_iterate;
1041	}
1042
1043	if (repl->valid_hooks != t->valid_hooks) {
1044		ret = -EINVAL;
1045		goto free_unlock;
1046	}
1047
1048	if (repl->num_counters && repl->num_counters != t->private->nentries) {
 
1049		ret = -EINVAL;
1050		goto free_unlock;
1051	}
1052
1053	/* we have the mutex lock, so no danger in reading this pointer */
1054	table = t->private;
1055	/* make sure the table can only be rmmod'ed if it contains no rules */
1056	if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1057		ret = -ENOENT;
1058		goto free_unlock;
1059	} else if (table->nentries && !newinfo->nentries)
1060		module_put(t->me);
1061	/* we need an atomic snapshot of the counters */
1062	write_lock_bh(&t->lock);
1063	if (repl->num_counters)
1064		get_counters(t->private->counters, counterstmp,
1065		   t->private->nentries);
1066
1067	t->private = newinfo;
1068	write_unlock_bh(&t->lock);
1069	mutex_unlock(&ebt_mutex);
1070	/* so, a user can change the chains while having messed up her counter
1071	 * allocation. Only reason why this is done is because this way the lock
1072	 * is held only once, while this doesn't bring the kernel into a
1073	 * dangerous state.
1074	 */
1075	if (repl->num_counters &&
1076	   copy_to_user(repl->counters, counterstmp,
1077	   array_size(repl->num_counters, sizeof(struct ebt_counter)))) {
1078		/* Silent error, can't fail, new table is already in place */
1079		net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1080	}
1081
1082	/* decrease module count and free resources */
1083	EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1084			  ebt_cleanup_entry, net, NULL);
1085
1086	vfree(table->entries);
1087	ebt_free_table_info(table);
 
 
 
 
1088	vfree(table);
 
1089	vfree(counterstmp);
1090
1091	audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1092			AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1093	return 0;
 
 
 
 
 
 
1094
1095free_unlock:
1096	mutex_unlock(&ebt_mutex);
1097free_iterate:
1098	EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1099			  ebt_cleanup_entry, net, NULL);
1100free_counterstmp:
1101	vfree(counterstmp);
1102	/* can be initialized in translate_table() */
1103	ebt_free_table_info(newinfo);
 
 
 
 
1104	return ret;
1105}
1106
1107/* replace the table */
1108static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
 
1109{
1110	int ret, countersize;
1111	struct ebt_table_info *newinfo;
1112	struct ebt_replace tmp;
1113
1114	if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1115		return -EFAULT;
1116
1117	if (len != sizeof(tmp) + tmp.entries_size)
 
1118		return -EINVAL;
 
1119
1120	if (tmp.entries_size == 0)
 
1121		return -EINVAL;
1122
1123	/* overflow check */
1124	if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1125			NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1126		return -ENOMEM;
1127	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1128		return -ENOMEM;
1129
1130	tmp.name[sizeof(tmp.name) - 1] = 0;
1131
1132	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1133	newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1134	if (!newinfo)
1135		return -ENOMEM;
1136
1137	if (countersize)
1138		memset(newinfo->counters, 0, countersize);
1139
1140	newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1141	if (!newinfo->entries) {
1142		ret = -ENOMEM;
1143		goto free_newinfo;
1144	}
1145	if (copy_from_user(
1146	   newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
 
1147		ret = -EFAULT;
1148		goto free_entries;
1149	}
1150
1151	ret = do_replace_finish(net, &tmp, newinfo);
1152	if (ret == 0)
1153		return ret;
1154free_entries:
1155	vfree(newinfo->entries);
1156free_newinfo:
1157	vfree(newinfo);
1158	return ret;
1159}
1160
1161static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1162{
 
 
1163	mutex_lock(&ebt_mutex);
1164	list_del(&table->list);
1165	mutex_unlock(&ebt_mutex);
1166	audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1167			AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1168	EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1169			  ebt_cleanup_entry, net, NULL);
1170	if (table->private->nentries)
1171		module_put(table->me);
1172	vfree(table->private->entries);
1173	ebt_free_table_info(table->private);
 
 
 
 
1174	vfree(table->private);
1175	kfree(table->ops);
1176	kfree(table);
1177}
1178
1179int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1180		       const struct nf_hook_ops *template_ops)
1181{
1182	struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1183	struct ebt_table_info *newinfo;
1184	struct ebt_table *t, *table;
1185	struct nf_hook_ops *ops;
1186	unsigned int num_ops;
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		return -EINVAL;
 
1195
1196	/* Don't add one table to multiple lists. */
1197	table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1198	if (!table) {
1199		ret = -ENOMEM;
1200		goto out;
1201	}
1202
1203	countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1204	newinfo = vmalloc(sizeof(*newinfo) + countersize);
1205	ret = -ENOMEM;
1206	if (!newinfo)
1207		goto free_table;
1208
1209	p = vmalloc(repl->entries_size);
1210	if (!p)
1211		goto free_newinfo;
1212
1213	memcpy(p, repl->entries, repl->entries_size);
1214	newinfo->entries = p;
1215
1216	newinfo->entries_size = repl->entries_size;
1217	newinfo->nentries = repl->nentries;
1218
1219	if (countersize)
1220		memset(newinfo->counters, 0, countersize);
1221
1222	/* fill in newinfo and parse the entries */
1223	newinfo->chainstack = NULL;
1224	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1225		if ((repl->valid_hooks & (1 << i)) == 0)
1226			newinfo->hook_entry[i] = NULL;
1227		else
1228			newinfo->hook_entry[i] = p +
1229				((char *)repl->hook_entry[i] - repl->entries);
1230	}
1231	ret = translate_table(net, repl->name, newinfo);
1232	if (ret != 0)
 
 
 
 
 
 
 
1233		goto free_chainstack;
 
1234
1235	table->private = newinfo;
1236	rwlock_init(&table->lock);
1237	mutex_lock(&ebt_mutex);
1238	list_for_each_entry(t, &ebt_net->tables, list) {
1239		if (strcmp(t->name, table->name) == 0) {
1240			ret = -EEXIST;
 
1241			goto free_unlock;
1242		}
1243	}
1244
1245	/* Hold a reference count if the chains aren't empty */
1246	if (newinfo->nentries && !try_module_get(table->me)) {
1247		ret = -ENOENT;
1248		goto free_unlock;
1249	}
 
 
1250
1251	num_ops = hweight32(table->valid_hooks);
1252	if (num_ops == 0) {
1253		ret = -EINVAL;
1254		goto free_unlock;
1255	}
1256
1257	ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1258	if (!ops) {
1259		ret = -ENOMEM;
1260		if (newinfo->nentries)
1261			module_put(table->me);
1262		goto free_unlock;
1263	}
1264
1265	for (i = 0; i < num_ops; i++)
1266		ops[i].priv = table;
1267
1268	list_add(&table->list, &ebt_net->tables);
1269	mutex_unlock(&ebt_mutex);
1270
1271	table->ops = ops;
1272	ret = nf_register_net_hooks(net, ops, num_ops);
1273	if (ret)
1274		__ebt_unregister_table(net, table);
 
 
1275
1276	audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1277			AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1278	return ret;
1279free_unlock:
1280	mutex_unlock(&ebt_mutex);
1281free_chainstack:
1282	ebt_free_table_info(newinfo);
 
 
 
 
1283	vfree(newinfo->entries);
1284free_newinfo:
1285	vfree(newinfo);
1286free_table:
1287	kfree(table);
1288out:
1289	return ret;
1290}
1291
1292int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1293{
1294	struct ebt_template *tmpl;
1295
1296	mutex_lock(&ebt_mutex);
1297	list_for_each_entry(tmpl, &template_tables, list) {
1298		if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1299			mutex_unlock(&ebt_mutex);
1300			return -EEXIST;
1301		}
1302	}
1303
1304	tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1305	if (!tmpl) {
1306		mutex_unlock(&ebt_mutex);
1307		return -ENOMEM;
1308	}
1309
1310	tmpl->table_init = table_init;
1311	strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1312	tmpl->owner = t->me;
1313	list_add(&tmpl->list, &template_tables);
1314
1315	mutex_unlock(&ebt_mutex);
1316	return 0;
1317}
1318EXPORT_SYMBOL(ebt_register_template);
1319
1320void ebt_unregister_template(const struct ebt_table *t)
1321{
1322	struct ebt_template *tmpl;
1323
1324	mutex_lock(&ebt_mutex);
1325	list_for_each_entry(tmpl, &template_tables, list) {
1326		if (strcmp(t->name, tmpl->name))
1327			continue;
1328
1329		list_del(&tmpl->list);
1330		mutex_unlock(&ebt_mutex);
1331		kfree(tmpl);
1332		return;
1333	}
1334
1335	mutex_unlock(&ebt_mutex);
1336	WARN_ON_ONCE(1);
1337}
1338EXPORT_SYMBOL(ebt_unregister_template);
1339
1340static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1341{
1342	struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1343	struct ebt_table *t;
1344
1345	mutex_lock(&ebt_mutex);
1346
1347	list_for_each_entry(t, &ebt_net->tables, list) {
1348		if (strcmp(t->name, name) == 0) {
1349			mutex_unlock(&ebt_mutex);
1350			return t;
1351		}
1352	}
1353
1354	mutex_unlock(&ebt_mutex);
1355	return NULL;
1356}
1357
1358void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1359{
1360	struct ebt_table *table = __ebt_find_table(net, name);
1361
1362	if (table)
1363		nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1364}
1365EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1366
1367void ebt_unregister_table(struct net *net, const char *name)
1368{
1369	struct ebt_table *table = __ebt_find_table(net, name);
1370
1371	if (table)
1372		__ebt_unregister_table(net, table);
1373}
1374
1375/* userspace just supplied us with counters */
1376static int do_update_counters(struct net *net, const char *name,
1377			      struct ebt_counter __user *counters,
1378			      unsigned int num_counters, unsigned int len)
 
1379{
1380	int i, ret;
1381	struct ebt_counter *tmp;
1382	struct ebt_table *t;
1383
1384	if (num_counters == 0)
1385		return -EINVAL;
1386
1387	tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1388	if (!tmp)
1389		return -ENOMEM;
1390
1391	t = find_table_lock(net, name, &ret, &ebt_mutex);
1392	if (!t)
1393		goto free_tmp;
1394
1395	if (num_counters != t->private->nentries) {
 
1396		ret = -EINVAL;
1397		goto unlock_mutex;
1398	}
1399
1400	if (copy_from_user(tmp, counters,
1401			   array_size(num_counters, sizeof(*counters)))) {
1402		ret = -EFAULT;
1403		goto unlock_mutex;
1404	}
1405
1406	/* we want an atomic add of the counters */
1407	write_lock_bh(&t->lock);
1408
1409	/* we add to the counters of the first cpu */
1410	for (i = 0; i < num_counters; i++)
1411		ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1412
1413	write_unlock_bh(&t->lock);
1414	ret = 0;
1415unlock_mutex:
1416	mutex_unlock(&ebt_mutex);
1417free_tmp:
1418	vfree(tmp);
1419	return ret;
1420}
1421
1422static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
 
1423{
1424	struct ebt_replace hlp;
1425
1426	if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1427		return -EFAULT;
1428
1429	if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1430		return -EINVAL;
1431
1432	return do_update_counters(net, hlp.name, hlp.counters,
1433				  hlp.num_counters, len);
1434}
1435
1436static inline int ebt_obj_to_user(char __user *um, const char *_name,
1437				  const char *data, int entrysize,
1438				  int usersize, int datasize, u8 revision)
1439{
1440	char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1441
1442	/* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1443	 * long. Copy 29 bytes and fill remaining bytes with zeroes.
1444	 */
1445	strscpy(name, _name, sizeof(name));
1446	if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1447	    put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1448	    put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1449	    xt_data_to_user(um + entrysize, data, usersize, datasize,
1450			    XT_ALIGN(datasize)))
1451		return -EFAULT;
1452
1453	return 0;
1454}
1455
1456static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1457				    const char *base, char __user *ubase)
1458{
1459	return ebt_obj_to_user(ubase + ((char *)m - base),
1460			       m->u.match->name, m->data, sizeof(*m),
1461			       m->u.match->usersize, m->match_size,
1462			       m->u.match->revision);
1463}
1464
1465static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1466				      const char *base, char __user *ubase)
1467{
1468	return ebt_obj_to_user(ubase + ((char *)w - base),
1469			       w->u.watcher->name, w->data, sizeof(*w),
1470			       w->u.watcher->usersize, w->watcher_size,
1471			       w->u.watcher->revision);
1472}
1473
1474static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1475				    char __user *ubase)
1476{
1477	int ret;
1478	char __user *hlp;
1479	const struct ebt_entry_target *t;
1480
1481	if (e->bitmask == 0) {
1482		/* special case !EBT_ENTRY_OR_ENTRIES */
1483		if (copy_to_user(ubase + ((char *)e - base), e,
1484				 sizeof(struct ebt_entries)))
1485			return -EFAULT;
1486		return 0;
1487	}
1488
1489	if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1490		return -EFAULT;
1491
1492	hlp = ubase + (((char *)e + e->target_offset) - base);
1493	t = ebt_get_target_c(e);
1494
1495	ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1496	if (ret != 0)
1497		return ret;
1498	ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1499	if (ret != 0)
1500		return ret;
1501	ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1502			      t->u.target->usersize, t->target_size,
1503			      t->u.target->revision);
1504	if (ret != 0)
1505		return ret;
1506
1507	return 0;
1508}
1509
1510static int copy_counters_to_user(struct ebt_table *t,
1511				 const struct ebt_counter *oldcounters,
1512				 void __user *user, unsigned int num_counters,
1513				 unsigned int nentries)
1514{
1515	struct ebt_counter *counterstmp;
1516	int ret = 0;
1517
1518	/* userspace might not need the counters */
1519	if (num_counters == 0)
1520		return 0;
1521
1522	if (num_counters != nentries)
 
1523		return -EINVAL;
 
1524
1525	counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1526	if (!counterstmp)
1527		return -ENOMEM;
1528
1529	write_lock_bh(&t->lock);
1530	get_counters(oldcounters, counterstmp, nentries);
1531	write_unlock_bh(&t->lock);
1532
1533	if (copy_to_user(user, counterstmp,
1534	    array_size(nentries, sizeof(struct ebt_counter))))
1535		ret = -EFAULT;
1536	vfree(counterstmp);
1537	return ret;
1538}
1539
1540/* called with ebt_mutex locked */
1541static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1542				   const int *len, int cmd)
1543{
1544	struct ebt_replace tmp;
1545	const struct ebt_counter *oldcounters;
1546	unsigned int entries_size, nentries;
1547	int ret;
1548	char *entries;
1549
1550	if (cmd == EBT_SO_GET_ENTRIES) {
1551		entries_size = t->private->entries_size;
1552		nentries = t->private->nentries;
1553		entries = t->private->entries;
1554		oldcounters = t->private->counters;
1555	} else {
1556		entries_size = t->table->entries_size;
1557		nentries = t->table->nentries;
1558		entries = t->table->entries;
1559		oldcounters = t->table->counters;
1560	}
1561
1562	if (copy_from_user(&tmp, user, sizeof(tmp)))
1563		return -EFAULT;
1564
1565	if (*len != sizeof(struct ebt_replace) + entries_size +
1566	   (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1567		return -EINVAL;
1568
1569	if (tmp.nentries != nentries)
 
1570		return -EINVAL;
 
1571
1572	if (tmp.entries_size != entries_size)
 
1573		return -EINVAL;
 
1574
1575	ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1576					tmp.num_counters, nentries);
1577	if (ret)
1578		return ret;
1579
1580	/* set the match/watcher/target names right */
1581	return EBT_ENTRY_ITERATE(entries, entries_size,
1582	   ebt_entry_to_user, entries, tmp.entries);
1583}
1584
1585#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1586/* 32 bit-userspace compatibility definitions. */
1587struct compat_ebt_replace {
1588	char name[EBT_TABLE_MAXNAMELEN];
1589	compat_uint_t valid_hooks;
1590	compat_uint_t nentries;
1591	compat_uint_t entries_size;
1592	/* start of the chains */
1593	compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1594	/* nr of counters userspace expects back */
1595	compat_uint_t num_counters;
1596	/* where the kernel will put the old counters. */
1597	compat_uptr_t counters;
1598	compat_uptr_t entries;
1599};
1600
1601/* struct ebt_entry_match, _target and _watcher have same layout */
1602struct compat_ebt_entry_mwt {
1603	union {
1604		struct {
1605			char name[EBT_EXTENSION_MAXNAMELEN];
1606			u8 revision;
1607		};
1608		compat_uptr_t ptr;
1609	} u;
1610	compat_uint_t match_size;
1611	compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1612};
1613
1614/* account for possible padding between match_size and ->data */
1615static int ebt_compat_entry_padsize(void)
1616{
1617	BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1618			sizeof(struct compat_ebt_entry_mwt));
1619	return (int) sizeof(struct ebt_entry_match) -
1620			sizeof(struct compat_ebt_entry_mwt);
1621}
1622
1623static int ebt_compat_match_offset(const struct xt_match *match,
1624				   unsigned int userlen)
1625{
1626	/* ebt_among needs special handling. The kernel .matchsize is
1627	 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1628	 * value is expected.
1629	 * Example: userspace sends 4500, ebt_among.c wants 4504.
1630	 */
1631	if (unlikely(match->matchsize == -1))
1632		return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1633	return xt_compat_match_offset(match);
1634}
1635
1636static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1637				unsigned int *size)
1638{
1639	const struct xt_match *match = m->u.match;
1640	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1641	int off = ebt_compat_match_offset(match, m->match_size);
1642	compat_uint_t msize = m->match_size - off;
1643
1644	if (WARN_ON(off >= m->match_size))
1645		return -EINVAL;
1646
1647	if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1648	    put_user(match->revision, &cm->u.revision) ||
1649	    put_user(msize, &cm->match_size))
1650		return -EFAULT;
1651
1652	if (match->compat_to_user) {
1653		if (match->compat_to_user(cm->data, m->data))
1654			return -EFAULT;
1655	} else {
1656		if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1657				    COMPAT_XT_ALIGN(msize)))
1658			return -EFAULT;
1659	}
1660
1661	*size -= ebt_compat_entry_padsize() + off;
1662	*dstptr = cm->data;
1663	*dstptr += msize;
1664	return 0;
1665}
1666
1667static int compat_target_to_user(struct ebt_entry_target *t,
1668				 void __user **dstptr,
1669				 unsigned int *size)
1670{
1671	const struct xt_target *target = t->u.target;
1672	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1673	int off = xt_compat_target_offset(target);
1674	compat_uint_t tsize = t->target_size - off;
1675
1676	if (WARN_ON(off >= t->target_size))
1677		return -EINVAL;
1678
1679	if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1680	    put_user(target->revision, &cm->u.revision) ||
1681	    put_user(tsize, &cm->match_size))
1682		return -EFAULT;
1683
1684	if (target->compat_to_user) {
1685		if (target->compat_to_user(cm->data, t->data))
1686			return -EFAULT;
1687	} else {
1688		if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1689				    COMPAT_XT_ALIGN(tsize)))
1690			return -EFAULT;
1691	}
1692
1693	*size -= ebt_compat_entry_padsize() + off;
1694	*dstptr = cm->data;
1695	*dstptr += tsize;
1696	return 0;
1697}
1698
1699static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1700				  void __user **dstptr,
1701				  unsigned int *size)
1702{
1703	return compat_target_to_user((struct ebt_entry_target *)w,
1704							dstptr, size);
1705}
1706
1707static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1708				unsigned int *size)
1709{
1710	struct ebt_entry_target *t;
1711	struct ebt_entry __user *ce;
1712	u32 watchers_offset, target_offset, next_offset;
1713	compat_uint_t origsize;
1714	int ret;
1715
1716	if (e->bitmask == 0) {
1717		if (*size < sizeof(struct ebt_entries))
1718			return -EINVAL;
1719		if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1720			return -EFAULT;
1721
1722		*dstptr += sizeof(struct ebt_entries);
1723		*size -= sizeof(struct ebt_entries);
1724		return 0;
1725	}
1726
1727	if (*size < sizeof(*ce))
1728		return -EINVAL;
1729
1730	ce = *dstptr;
1731	if (copy_to_user(ce, e, sizeof(*ce)))
1732		return -EFAULT;
1733
1734	origsize = *size;
1735	*dstptr += sizeof(*ce);
1736
1737	ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1738	if (ret)
1739		return ret;
1740	watchers_offset = e->watchers_offset - (origsize - *size);
1741
1742	ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1743	if (ret)
1744		return ret;
1745	target_offset = e->target_offset - (origsize - *size);
1746
1747	t = ebt_get_target(e);
1748
1749	ret = compat_target_to_user(t, dstptr, size);
1750	if (ret)
1751		return ret;
1752	next_offset = e->next_offset - (origsize - *size);
1753
1754	if (put_user(watchers_offset, &ce->watchers_offset) ||
1755	    put_user(target_offset, &ce->target_offset) ||
1756	    put_user(next_offset, &ce->next_offset))
1757		return -EFAULT;
1758
1759	*size -= sizeof(*ce);
1760	return 0;
1761}
1762
1763static int compat_calc_match(struct ebt_entry_match *m, int *off)
1764{
1765	*off += ebt_compat_match_offset(m->u.match, m->match_size);
1766	*off += ebt_compat_entry_padsize();
1767	return 0;
1768}
1769
1770static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1771{
1772	*off += xt_compat_target_offset(w->u.watcher);
1773	*off += ebt_compat_entry_padsize();
1774	return 0;
1775}
1776
1777static int compat_calc_entry(const struct ebt_entry *e,
1778			     const struct ebt_table_info *info,
1779			     const void *base,
1780			     struct compat_ebt_replace *newinfo)
1781{
1782	const struct ebt_entry_target *t;
1783	unsigned int entry_offset;
1784	int off, ret, i;
1785
1786	if (e->bitmask == 0)
1787		return 0;
1788
1789	off = 0;
1790	entry_offset = (void *)e - base;
1791
1792	EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1793	EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1794
1795	t = ebt_get_target_c(e);
1796
1797	off += xt_compat_target_offset(t->u.target);
1798	off += ebt_compat_entry_padsize();
1799
1800	newinfo->entries_size -= off;
1801
1802	ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1803	if (ret)
1804		return ret;
1805
1806	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1807		const void *hookptr = info->hook_entry[i];
1808		if (info->hook_entry[i] &&
1809		    (e < (struct ebt_entry *)(base - hookptr))) {
1810			newinfo->hook_entry[i] -= off;
1811			pr_debug("0x%08X -> 0x%08X\n",
1812					newinfo->hook_entry[i] + off,
1813					newinfo->hook_entry[i]);
1814		}
1815	}
1816
1817	return 0;
1818}
1819
1820static int ebt_compat_init_offsets(unsigned int number)
1821{
1822	if (number > INT_MAX)
1823		return -EINVAL;
1824
1825	/* also count the base chain policies */
1826	number += NF_BR_NUMHOOKS;
1827
1828	return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1829}
1830
1831static int compat_table_info(const struct ebt_table_info *info,
1832			     struct compat_ebt_replace *newinfo)
1833{
1834	unsigned int size = info->entries_size;
1835	const void *entries = info->entries;
1836	int ret;
1837
1838	newinfo->entries_size = size;
1839	ret = ebt_compat_init_offsets(info->nentries);
1840	if (ret)
1841		return ret;
 
 
 
1842
1843	return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1844							entries, newinfo);
1845}
1846
1847static int compat_copy_everything_to_user(struct ebt_table *t,
1848					  void __user *user, int *len, int cmd)
1849{
1850	struct compat_ebt_replace repl, tmp;
1851	struct ebt_counter *oldcounters;
1852	struct ebt_table_info tinfo;
1853	int ret;
1854	void __user *pos;
1855
1856	memset(&tinfo, 0, sizeof(tinfo));
1857
1858	if (cmd == EBT_SO_GET_ENTRIES) {
1859		tinfo.entries_size = t->private->entries_size;
1860		tinfo.nentries = t->private->nentries;
1861		tinfo.entries = t->private->entries;
1862		oldcounters = t->private->counters;
1863	} else {
1864		tinfo.entries_size = t->table->entries_size;
1865		tinfo.nentries = t->table->nentries;
1866		tinfo.entries = t->table->entries;
1867		oldcounters = t->table->counters;
1868	}
1869
1870	if (copy_from_user(&tmp, user, sizeof(tmp)))
1871		return -EFAULT;
1872
1873	if (tmp.nentries != tinfo.nentries ||
1874	   (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1875		return -EINVAL;
1876
1877	memcpy(&repl, &tmp, sizeof(repl));
1878	if (cmd == EBT_SO_GET_ENTRIES)
1879		ret = compat_table_info(t->private, &repl);
1880	else
1881		ret = compat_table_info(&tinfo, &repl);
1882	if (ret)
1883		return ret;
1884
1885	if (*len != sizeof(tmp) + repl.entries_size +
1886	   (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1887		pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1888				*len, tinfo.entries_size, repl.entries_size);
1889		return -EINVAL;
1890	}
1891
1892	/* userspace might not need the counters */
1893	ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1894					tmp.num_counters, tinfo.nentries);
1895	if (ret)
1896		return ret;
1897
1898	pos = compat_ptr(tmp.entries);
1899	return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1900			compat_copy_entry_to_user, &pos, &tmp.entries_size);
1901}
1902
1903struct ebt_entries_buf_state {
1904	char *buf_kern_start;	/* kernel buffer to copy (translated) data to */
1905	u32 buf_kern_len;	/* total size of kernel buffer */
1906	u32 buf_kern_offset;	/* amount of data copied so far */
1907	u32 buf_user_offset;	/* read position in userspace buffer */
1908};
1909
1910static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1911{
1912	state->buf_kern_offset += sz;
1913	return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1914}
1915
1916static int ebt_buf_add(struct ebt_entries_buf_state *state,
1917		       const void *data, unsigned int sz)
1918{
1919	if (state->buf_kern_start == NULL)
1920		goto count_only;
1921
1922	if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1923		return -EINVAL;
1924
1925	memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1926
1927 count_only:
1928	state->buf_user_offset += sz;
1929	return ebt_buf_count(state, sz);
1930}
1931
1932static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1933{
1934	char *b = state->buf_kern_start;
1935
1936	if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1937		return -EINVAL;
1938
1939	if (b != NULL && sz > 0)
1940		memset(b + state->buf_kern_offset, 0, sz);
1941	/* do not adjust ->buf_user_offset here, we added kernel-side padding */
1942	return ebt_buf_count(state, sz);
1943}
1944
1945enum compat_mwt {
1946	EBT_COMPAT_MATCH,
1947	EBT_COMPAT_WATCHER,
1948	EBT_COMPAT_TARGET,
1949};
1950
1951static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1952				enum compat_mwt compat_mwt,
1953				struct ebt_entries_buf_state *state,
1954				const unsigned char *base)
1955{
1956	char name[EBT_EXTENSION_MAXNAMELEN];
1957	struct xt_match *match;
1958	struct xt_target *wt;
1959	void *dst = NULL;
1960	int off, pad = 0;
1961	unsigned int size_kern, match_size = mwt->match_size;
1962
1963	if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1964		return -EINVAL;
1965
1966	if (state->buf_kern_start)
1967		dst = state->buf_kern_start + state->buf_kern_offset;
1968
1969	switch (compat_mwt) {
1970	case EBT_COMPAT_MATCH:
1971		match = xt_request_find_match(NFPROTO_BRIDGE, name,
1972					      mwt->u.revision);
1973		if (IS_ERR(match))
1974			return PTR_ERR(match);
1975
1976		off = ebt_compat_match_offset(match, match_size);
1977		if (dst) {
1978			if (match->compat_from_user)
1979				match->compat_from_user(dst, mwt->data);
1980			else
1981				memcpy(dst, mwt->data, match_size);
1982		}
1983
1984		size_kern = match->matchsize;
1985		if (unlikely(size_kern == -1))
1986			size_kern = match_size;
1987		module_put(match->me);
1988		break;
1989	case EBT_COMPAT_WATCHER:
1990	case EBT_COMPAT_TARGET:
1991		wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1992					    mwt->u.revision);
1993		if (IS_ERR(wt))
1994			return PTR_ERR(wt);
1995		off = xt_compat_target_offset(wt);
1996
1997		if (dst) {
1998			if (wt->compat_from_user)
1999				wt->compat_from_user(dst, mwt->data);
2000			else
2001				memcpy(dst, mwt->data, match_size);
2002		}
2003
2004		size_kern = wt->targetsize;
2005		module_put(wt->me);
2006		break;
2007
2008	default:
2009		return -EINVAL;
2010	}
2011
2012	state->buf_kern_offset += match_size + off;
2013	state->buf_user_offset += match_size;
2014	pad = XT_ALIGN(size_kern) - size_kern;
2015
2016	if (pad > 0 && dst) {
2017		if (WARN_ON(state->buf_kern_len <= pad))
2018			return -EINVAL;
2019		if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2020			return -EINVAL;
2021		memset(dst + size_kern, 0, pad);
2022	}
2023	return off + match_size;
2024}
2025
2026/* return size of all matches, watchers or target, including necessary
2027 * alignment and padding.
2028 */
2029static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2030			unsigned int size_left, enum compat_mwt type,
2031			struct ebt_entries_buf_state *state, const void *base)
2032{
2033	const char *buf = (const char *)match32;
2034	int growth = 0;
 
2035
2036	if (size_left == 0)
2037		return 0;
2038
2039	do {
 
 
2040		struct ebt_entry_match *match_kern;
2041		int ret;
2042
2043		if (size_left < sizeof(*match32))
2044			return -EINVAL;
2045
2046		match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2047		if (match_kern) {
2048			char *tmp;
2049			tmp = state->buf_kern_start + state->buf_kern_offset;
2050			match_kern = (struct ebt_entry_match *) tmp;
2051		}
2052		ret = ebt_buf_add(state, buf, sizeof(*match32));
2053		if (ret < 0)
2054			return ret;
2055		size_left -= sizeof(*match32);
2056
2057		/* add padding before match->data (if any) */
2058		ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2059		if (ret < 0)
2060			return ret;
2061
2062		if (match32->match_size > size_left)
2063			return -EINVAL;
2064
2065		size_left -= match32->match_size;
2066
2067		ret = compat_mtw_from_user(match32, type, state, base);
2068		if (ret < 0)
2069			return ret;
2070
2071		if (WARN_ON(ret < match32->match_size))
2072			return -EINVAL;
2073		growth += ret - match32->match_size;
2074		growth += ebt_compat_entry_padsize();
2075
2076		buf += sizeof(*match32);
2077		buf += match32->match_size;
2078
2079		if (match_kern)
2080			match_kern->match_size = ret;
2081
 
 
 
2082		match32 = (struct compat_ebt_entry_mwt *) buf;
2083	} while (size_left);
2084
2085	return growth;
2086}
2087
2088/* called for all ebt_entry structures. */
2089static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2090			  unsigned int *total,
2091			  struct ebt_entries_buf_state *state)
2092{
2093	unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2094	/* stores match/watchers/targets & offset of next struct ebt_entry: */
2095	unsigned int offsets[4];
2096	unsigned int *offsets_update = NULL;
2097	int ret;
2098	char *buf_start;
2099
2100	if (*total < sizeof(struct ebt_entries))
2101		return -EINVAL;
2102
2103	if (!entry->bitmask) {
2104		*total -= sizeof(struct ebt_entries);
2105		return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2106	}
2107	if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2108		return -EINVAL;
2109
2110	startoff = state->buf_user_offset;
2111	/* pull in most part of ebt_entry, it does not need to be changed. */
2112	ret = ebt_buf_add(state, entry,
2113			offsetof(struct ebt_entry, watchers_offset));
2114	if (ret < 0)
2115		return ret;
2116
2117	offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2118	memcpy(&offsets[1], &entry->offsets, sizeof(entry->offsets));
 
2119
2120	if (state->buf_kern_start) {
2121		buf_start = state->buf_kern_start + state->buf_kern_offset;
2122		offsets_update = (unsigned int *) buf_start;
2123	}
2124	ret = ebt_buf_add(state, &offsets[1],
2125			sizeof(offsets) - sizeof(offsets[0]));
2126	if (ret < 0)
2127		return ret;
2128	buf_start = (char *) entry;
2129	/* 0: matches offset, always follows ebt_entry.
2130	 * 1: watchers offset, from ebt_entry structure
2131	 * 2: target offset, from ebt_entry structure
2132	 * 3: next ebt_entry offset, from ebt_entry structure
2133	 *
2134	 * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2135	 */
2136	for (i = 0; i < 4 ; ++i) {
2137		if (offsets[i] > *total)
2138			return -EINVAL;
2139
2140		if (i < 3 && offsets[i] == *total)
2141			return -EINVAL;
2142
2143		if (i == 0)
2144			continue;
2145		if (offsets[i-1] > offsets[i])
2146			return -EINVAL;
2147	}
2148
2149	for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2150		struct compat_ebt_entry_mwt *match32;
2151		unsigned int size;
2152		char *buf = buf_start + offsets[i];
2153
2154		if (offsets[i] > offsets[j])
2155			return -EINVAL;
2156
2157		match32 = (struct compat_ebt_entry_mwt *) buf;
2158		size = offsets[j] - offsets[i];
2159		ret = ebt_size_mwt(match32, size, i, state, base);
2160		if (ret < 0)
2161			return ret;
2162		new_offset += ret;
2163		if (offsets_update && new_offset) {
2164			pr_debug("change offset %d to %d\n",
2165				offsets_update[i], offsets[j] + new_offset);
2166			offsets_update[i] = offsets[j] + new_offset;
2167		}
2168	}
2169
2170	if (state->buf_kern_start == NULL) {
2171		unsigned int offset = buf_start - (char *) base;
2172
2173		ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2174		if (ret < 0)
2175			return ret;
2176	}
2177
2178	next_expected_off = state->buf_user_offset - startoff;
2179	if (next_expected_off != entry->next_offset)
2180		return -EINVAL;
2181
2182	if (*total < entry->next_offset)
2183		return -EINVAL;
2184	*total -= entry->next_offset;
2185	return 0;
2186}
2187
2188/* repl->entries_size is the size of the ebt_entry blob in userspace.
2189 * It might need more memory when copied to a 64 bit kernel in case
2190 * userspace is 32-bit. So, first task: find out how much memory is needed.
2191 *
2192 * Called before validation is performed.
2193 */
2194static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2195				struct ebt_entries_buf_state *state)
2196{
2197	unsigned int size_remaining = size_user;
2198	int ret;
2199
2200	ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2201					&size_remaining, state);
2202	if (ret < 0)
2203		return ret;
2204
2205	if (size_remaining)
2206		return -EINVAL;
2207
2208	return state->buf_kern_offset;
2209}
2210
2211
2212static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2213					     sockptr_t arg, unsigned int len)
2214{
2215	struct compat_ebt_replace tmp;
2216	int i;
2217
2218	if (len < sizeof(tmp))
2219		return -EINVAL;
2220
2221	if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2222		return -EFAULT;
2223
2224	if (len != sizeof(tmp) + tmp.entries_size)
2225		return -EINVAL;
2226
2227	if (tmp.entries_size == 0)
2228		return -EINVAL;
2229
2230	if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2231			NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2232		return -ENOMEM;
2233	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2234		return -ENOMEM;
2235
2236	memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2237
2238	/* starting with hook_entry, 32 vs. 64 bit structures are different */
2239	for (i = 0; i < NF_BR_NUMHOOKS; i++)
2240		repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2241
2242	repl->num_counters = tmp.num_counters;
2243	repl->counters = compat_ptr(tmp.counters);
2244	repl->entries = compat_ptr(tmp.entries);
2245	return 0;
2246}
2247
2248static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
 
2249{
2250	int ret, i, countersize, size64;
2251	struct ebt_table_info *newinfo;
2252	struct ebt_replace tmp;
2253	struct ebt_entries_buf_state state;
2254	void *entries_tmp;
2255
2256	ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2257	if (ret) {
2258		/* try real handler in case userland supplied needed padding */
2259		if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2260			ret = 0;
2261		return ret;
2262	}
2263
2264	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2265	newinfo = vmalloc(sizeof(*newinfo) + countersize);
2266	if (!newinfo)
2267		return -ENOMEM;
2268
2269	if (countersize)
2270		memset(newinfo->counters, 0, countersize);
2271
2272	memset(&state, 0, sizeof(state));
2273
2274	newinfo->entries = vmalloc(tmp.entries_size);
2275	if (!newinfo->entries) {
2276		ret = -ENOMEM;
2277		goto free_newinfo;
2278	}
2279	if (copy_from_user(
2280	   newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2281		ret = -EFAULT;
2282		goto free_entries;
2283	}
2284
2285	entries_tmp = newinfo->entries;
2286
2287	xt_compat_lock(NFPROTO_BRIDGE);
2288
2289	ret = ebt_compat_init_offsets(tmp.nentries);
2290	if (ret < 0)
2291		goto out_unlock;
2292
2293	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2294	if (ret < 0)
2295		goto out_unlock;
2296
2297	pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2298		tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2299		xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2300
2301	size64 = ret;
2302	newinfo->entries = vmalloc(size64);
2303	if (!newinfo->entries) {
2304		vfree(entries_tmp);
2305		ret = -ENOMEM;
2306		goto out_unlock;
2307	}
2308
2309	memset(&state, 0, sizeof(state));
2310	state.buf_kern_start = newinfo->entries;
2311	state.buf_kern_len = size64;
2312
2313	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2314	if (WARN_ON(ret < 0)) {
2315		vfree(entries_tmp);
2316		goto out_unlock;
2317	}
2318
2319	vfree(entries_tmp);
2320	tmp.entries_size = size64;
2321
2322	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2323		char __user *usrptr;
2324		if (tmp.hook_entry[i]) {
2325			unsigned int delta;
2326			usrptr = (char __user *) tmp.hook_entry[i];
2327			delta = usrptr - tmp.entries;
2328			usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2329			tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2330		}
2331	}
2332
2333	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2334	xt_compat_unlock(NFPROTO_BRIDGE);
2335
2336	ret = do_replace_finish(net, &tmp, newinfo);
2337	if (ret == 0)
2338		return ret;
2339free_entries:
2340	vfree(newinfo->entries);
2341free_newinfo:
2342	vfree(newinfo);
2343	return ret;
2344out_unlock:
2345	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2346	xt_compat_unlock(NFPROTO_BRIDGE);
2347	goto free_entries;
2348}
2349
2350static int compat_update_counters(struct net *net, sockptr_t arg,
2351				  unsigned int len)
2352{
2353	struct compat_ebt_replace hlp;
2354
2355	if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2356		return -EFAULT;
2357
2358	/* try real handler in case userland supplied needed padding */
2359	if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2360		return update_counters(net, arg, len);
2361
2362	return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2363				  hlp.num_counters, len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2364}
2365
2366static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2367		void __user *user, int *len)
2368{
2369	int ret;
2370	struct compat_ebt_replace tmp;
2371	struct ebt_table *t;
2372	struct net *net = sock_net(sk);
2373
2374	if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2375	    *len != sizeof(struct compat_ebt_replace))
2376		return -EINVAL;
 
 
 
 
2377
2378	if (copy_from_user(&tmp, user, sizeof(tmp)))
2379		return -EFAULT;
2380
2381	tmp.name[sizeof(tmp.name) - 1] = '\0';
2382
2383	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2384	if (!t)
2385		return ret;
2386
2387	xt_compat_lock(NFPROTO_BRIDGE);
2388	switch (cmd) {
2389	case EBT_SO_GET_INFO:
2390		tmp.nentries = t->private->nentries;
2391		ret = compat_table_info(t->private, &tmp);
2392		if (ret)
2393			goto out;
2394		tmp.valid_hooks = t->valid_hooks;
2395
2396		if (copy_to_user(user, &tmp, *len) != 0) {
2397			ret = -EFAULT;
2398			break;
2399		}
2400		ret = 0;
2401		break;
2402	case EBT_SO_GET_INIT_INFO:
2403		tmp.nentries = t->table->nentries;
2404		tmp.entries_size = t->table->entries_size;
2405		tmp.valid_hooks = t->table->valid_hooks;
2406
2407		if (copy_to_user(user, &tmp, *len) != 0) {
2408			ret = -EFAULT;
2409			break;
2410		}
2411		ret = 0;
2412		break;
2413	case EBT_SO_GET_ENTRIES:
2414	case EBT_SO_GET_INIT_ENTRIES:
2415		/* try real handler first in case of userland-side padding.
2416		 * in case we are dealing with an 'ordinary' 32 bit binary
2417		 * without 64bit compatibility padding, this will fail right
2418		 * after copy_from_user when the *len argument is validated.
2419		 *
2420		 * the compat_ variant needs to do one pass over the kernel
2421		 * data set to adjust for size differences before it the check.
2422		 */
2423		if (copy_everything_to_user(t, user, len, cmd) == 0)
2424			ret = 0;
2425		else
2426			ret = compat_copy_everything_to_user(t, user, len, cmd);
2427		break;
2428	default:
2429		ret = -EINVAL;
2430	}
2431 out:
2432	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2433	xt_compat_unlock(NFPROTO_BRIDGE);
2434	mutex_unlock(&ebt_mutex);
2435	return ret;
2436}
2437#endif
2438
2439static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2440{
2441	struct net *net = sock_net(sk);
2442	struct ebt_replace tmp;
2443	struct ebt_table *t;
2444	int ret;
2445
2446	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2447		return -EPERM;
2448
2449#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2450	/* try real handler in case userland supplied needed padding */
2451	if (in_compat_syscall() &&
2452	    ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2453	     *len != sizeof(tmp)))
2454		return compat_do_ebt_get_ctl(sk, cmd, user, len);
2455#endif
2456
2457	if (copy_from_user(&tmp, user, sizeof(tmp)))
2458		return -EFAULT;
2459
2460	tmp.name[sizeof(tmp.name) - 1] = '\0';
2461
2462	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2463	if (!t)
2464		return ret;
2465
2466	switch (cmd) {
2467	case EBT_SO_GET_INFO:
2468	case EBT_SO_GET_INIT_INFO:
2469		if (*len != sizeof(struct ebt_replace)) {
2470			ret = -EINVAL;
2471			mutex_unlock(&ebt_mutex);
2472			break;
2473		}
2474		if (cmd == EBT_SO_GET_INFO) {
2475			tmp.nentries = t->private->nentries;
2476			tmp.entries_size = t->private->entries_size;
2477			tmp.valid_hooks = t->valid_hooks;
2478		} else {
2479			tmp.nentries = t->table->nentries;
2480			tmp.entries_size = t->table->entries_size;
2481			tmp.valid_hooks = t->table->valid_hooks;
2482		}
2483		mutex_unlock(&ebt_mutex);
2484		if (copy_to_user(user, &tmp, *len) != 0) {
2485			ret = -EFAULT;
2486			break;
2487		}
2488		ret = 0;
2489		break;
2490
2491	case EBT_SO_GET_ENTRIES:
2492	case EBT_SO_GET_INIT_ENTRIES:
2493		ret = copy_everything_to_user(t, user, len, cmd);
2494		mutex_unlock(&ebt_mutex);
2495		break;
2496
2497	default:
2498		mutex_unlock(&ebt_mutex);
2499		ret = -EINVAL;
2500	}
2501
2502	return ret;
2503}
2504
2505static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2506		unsigned int len)
2507{
2508	struct net *net = sock_net(sk);
2509	int ret;
2510
2511	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2512		return -EPERM;
2513
2514	switch (cmd) {
2515	case EBT_SO_SET_ENTRIES:
2516#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2517		if (in_compat_syscall())
2518			ret = compat_do_replace(net, arg, len);
2519		else
2520#endif
2521			ret = do_replace(net, arg, len);
2522		break;
2523	case EBT_SO_SET_COUNTERS:
2524#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2525		if (in_compat_syscall())
2526			ret = compat_update_counters(net, arg, len);
2527		else
2528#endif
2529			ret = update_counters(net, arg, len);
2530		break;
2531	default:
2532		ret = -EINVAL;
2533	}
2534	return ret;
2535}
2536
2537static struct nf_sockopt_ops ebt_sockopts = {
2538	.pf		= PF_INET,
2539	.set_optmin	= EBT_BASE_CTL,
2540	.set_optmax	= EBT_SO_SET_MAX + 1,
2541	.set		= do_ebt_set_ctl,
 
 
 
2542	.get_optmin	= EBT_BASE_CTL,
2543	.get_optmax	= EBT_SO_GET_MAX + 1,
2544	.get		= do_ebt_get_ctl,
 
 
 
2545	.owner		= THIS_MODULE,
2546};
2547
2548static int __net_init ebt_pernet_init(struct net *net)
2549{
2550	struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2551
2552	INIT_LIST_HEAD(&ebt_net->tables);
2553	return 0;
2554}
2555
2556static struct pernet_operations ebt_net_ops = {
2557	.init = ebt_pernet_init,
2558	.id   = &ebt_pernet_id,
2559	.size = sizeof(struct ebt_pernet),
2560};
2561
2562static int __init ebtables_init(void)
2563{
2564	int ret;
2565
2566	ret = xt_register_target(&ebt_standard_target);
2567	if (ret < 0)
2568		return ret;
2569	ret = nf_register_sockopt(&ebt_sockopts);
2570	if (ret < 0) {
2571		xt_unregister_target(&ebt_standard_target);
2572		return ret;
2573	}
2574
2575	ret = register_pernet_subsys(&ebt_net_ops);
2576	if (ret < 0) {
2577		nf_unregister_sockopt(&ebt_sockopts);
2578		xt_unregister_target(&ebt_standard_target);
2579		return ret;
2580	}
2581
2582	return 0;
2583}
2584
2585static void ebtables_fini(void)
2586{
2587	nf_unregister_sockopt(&ebt_sockopts);
2588	xt_unregister_target(&ebt_standard_target);
2589	unregister_pernet_subsys(&ebt_net_ops);
2590}
2591
2592EXPORT_SYMBOL(ebt_register_table);
2593EXPORT_SYMBOL(ebt_unregister_table);
2594EXPORT_SYMBOL(ebt_do_table);
2595module_init(ebtables_init);
2596module_exit(ebtables_fini);
2597MODULE_LICENSE("GPL");
2598MODULE_DESCRIPTION("ebtables legacy core");