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/net/bridge/netfilter/ebtables.c

http://github.com/mirrors/linux
C | 2464 lines | 1925 code | 360 blank | 179 comment | 487 complexity | cf71b9ca7ab48fa5e813ad97fe1d7510 MD5 | raw file

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   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/* needed for logical [in,out]-dev filtering */
  28#include "../br_private.h"
  29
  30/* Each cpu has its own set of counters, so there is no need for write_lock in
  31 * the softirq
  32 * For reading or updating the counters, the user context needs to
  33 * get a write_lock
  34 */
  35
  36/* The size of each set of counters is altered to get cache alignment */
  37#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  38#define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
  39#define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
  40				 COUNTER_OFFSET(n) * cpu))
  41
  42
  43
  44static DEFINE_MUTEX(ebt_mutex);
  45
  46#ifdef CONFIG_COMPAT
  47static void ebt_standard_compat_from_user(void *dst, const void *src)
  48{
  49	int v = *(compat_int_t *)src;
  50
  51	if (v >= 0)
  52		v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
  53	memcpy(dst, &v, sizeof(v));
  54}
  55
  56static int ebt_standard_compat_to_user(void __user *dst, const void *src)
  57{
  58	compat_int_t cv = *(int *)src;
  59
  60	if (cv >= 0)
  61		cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
  62	return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  63}
  64#endif
  65
  66
  67static struct xt_target ebt_standard_target = {
  68	.name       = "standard",
  69	.revision   = 0,
  70	.family     = NFPROTO_BRIDGE,
  71	.targetsize = sizeof(int),
  72#ifdef CONFIG_COMPAT
  73	.compatsize = sizeof(compat_int_t),
  74	.compat_from_user = ebt_standard_compat_from_user,
  75	.compat_to_user =  ebt_standard_compat_to_user,
  76#endif
  77};
  78
  79static inline int
  80ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
  81	       struct xt_action_param *par)
  82{
  83	par->target   = w->u.watcher;
  84	par->targinfo = w->data;
  85	w->u.watcher->target(skb, par);
  86	/* watchers don't give a verdict */
  87	return 0;
  88}
  89
  90static inline int
  91ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
  92	     struct xt_action_param *par)
  93{
  94	par->match     = m->u.match;
  95	par->matchinfo = m->data;
  96	return !m->u.match->match(skb, par);
  97}
  98
  99static inline int
 100ebt_dev_check(const char *entry, const struct net_device *device)
 101{
 102	int i = 0;
 103	const char *devname;
 104
 105	if (*entry == '\0')
 106		return 0;
 107	if (!device)
 108		return 1;
 109	devname = device->name;
 110	/* 1 is the wildcard token */
 111	while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
 112		i++;
 113	return devname[i] != entry[i] && entry[i] != 1;
 114}
 115
 116/* process standard matches */
 117static inline int
 118ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 119		const struct net_device *in, const struct net_device *out)
 120{
 121	const struct ethhdr *h = eth_hdr(skb);
 122	const struct net_bridge_port *p;
 123	__be16 ethproto;
 124
 125	if (skb_vlan_tag_present(skb))
 126		ethproto = htons(ETH_P_8021Q);
 127	else
 128		ethproto = h->h_proto;
 129
 130	if (e->bitmask & EBT_802_3) {
 131		if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
 132			return 1;
 133	} else if (!(e->bitmask & EBT_NOPROTO) &&
 134		   NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
 135		return 1;
 136
 137	if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
 138		return 1;
 139	if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 140		return 1;
 141	/* rcu_read_lock()ed by nf_hook_thresh */
 142	if (in && (p = br_port_get_rcu(in)) != NULL &&
 143	    NF_INVF(e, EBT_ILOGICALIN,
 144		    ebt_dev_check(e->logical_in, p->br->dev)))
 145		return 1;
 146	if (out && (p = br_port_get_rcu(out)) != NULL &&
 147	    NF_INVF(e, EBT_ILOGICALOUT,
 148		    ebt_dev_check(e->logical_out, p->br->dev)))
 149		return 1;
 150
 151	if (e->bitmask & EBT_SOURCEMAC) {
 152		if (NF_INVF(e, EBT_ISOURCE,
 153			    !ether_addr_equal_masked(h->h_source, e->sourcemac,
 154						     e->sourcemsk)))
 155			return 1;
 156	}
 157	if (e->bitmask & EBT_DESTMAC) {
 158		if (NF_INVF(e, EBT_IDEST,
 159			    !ether_addr_equal_masked(h->h_dest, e->destmac,
 160						     e->destmsk)))
 161			return 1;
 162	}
 163	return 0;
 164}
 165
 166static inline
 167struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
 168{
 169	return (void *)entry + entry->next_offset;
 170}
 171
 172static inline const struct ebt_entry_target *
 173ebt_get_target_c(const struct ebt_entry *e)
 174{
 175	return ebt_get_target((struct ebt_entry *)e);
 176}
 177
 178/* Do some firewalling */
 179unsigned int ebt_do_table(struct sk_buff *skb,
 180			  const struct nf_hook_state *state,
 181			  struct ebt_table *table)
 182{
 183	unsigned int hook = state->hook;
 184	int i, nentries;
 185	struct ebt_entry *point;
 186	struct ebt_counter *counter_base, *cb_base;
 187	const struct ebt_entry_target *t;
 188	int verdict, sp = 0;
 189	struct ebt_chainstack *cs;
 190	struct ebt_entries *chaininfo;
 191	const char *base;
 192	const struct ebt_table_info *private;
 193	struct xt_action_param acpar;
 194
 195	acpar.state   = state;
 196	acpar.hotdrop = false;
 197
 198	read_lock_bh(&table->lock);
 199	private = table->private;
 200	cb_base = COUNTER_BASE(private->counters, private->nentries,
 201	   smp_processor_id());
 202	if (private->chainstack)
 203		cs = private->chainstack[smp_processor_id()];
 204	else
 205		cs = NULL;
 206	chaininfo = private->hook_entry[hook];
 207	nentries = private->hook_entry[hook]->nentries;
 208	point = (struct ebt_entry *)(private->hook_entry[hook]->data);
 209	counter_base = cb_base + private->hook_entry[hook]->counter_offset;
 210	/* base for chain jumps */
 211	base = private->entries;
 212	i = 0;
 213	while (i < nentries) {
 214		if (ebt_basic_match(point, skb, state->in, state->out))
 215			goto letscontinue;
 216
 217		if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
 218			goto letscontinue;
 219		if (acpar.hotdrop) {
 220			read_unlock_bh(&table->lock);
 221			return NF_DROP;
 222		}
 223
 224		ADD_COUNTER(*(counter_base + i), skb->len, 1);
 225
 226		/* these should only watch: not modify, nor tell us
 227		 * what to do with the packet
 228		 */
 229		EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 230
 231		t = ebt_get_target_c(point);
 232		/* standard target */
 233		if (!t->u.target->target)
 234			verdict = ((struct ebt_standard_target *)t)->verdict;
 235		else {
 236			acpar.target   = t->u.target;
 237			acpar.targinfo = t->data;
 238			verdict = t->u.target->target(skb, &acpar);
 239		}
 240		if (verdict == EBT_ACCEPT) {
 241			read_unlock_bh(&table->lock);
 242			return NF_ACCEPT;
 243		}
 244		if (verdict == EBT_DROP) {
 245			read_unlock_bh(&table->lock);
 246			return NF_DROP;
 247		}
 248		if (verdict == EBT_RETURN) {
 249letsreturn:
 250			if (WARN(sp == 0, "RETURN on base chain")) {
 251				/* act like this is EBT_CONTINUE */
 252				goto letscontinue;
 253			}
 254
 255			sp--;
 256			/* put all the local variables right */
 257			i = cs[sp].n;
 258			chaininfo = cs[sp].chaininfo;
 259			nentries = chaininfo->nentries;
 260			point = cs[sp].e;
 261			counter_base = cb_base +
 262			   chaininfo->counter_offset;
 263			continue;
 264		}
 265		if (verdict == EBT_CONTINUE)
 266			goto letscontinue;
 267
 268		if (WARN(verdict < 0, "bogus standard verdict\n")) {
 269			read_unlock_bh(&table->lock);
 270			return NF_DROP;
 271		}
 272
 273		/* jump to a udc */
 274		cs[sp].n = i + 1;
 275		cs[sp].chaininfo = chaininfo;
 276		cs[sp].e = ebt_next_entry(point);
 277		i = 0;
 278		chaininfo = (struct ebt_entries *) (base + verdict);
 279
 280		if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
 281			read_unlock_bh(&table->lock);
 282			return NF_DROP;
 283		}
 284
 285		nentries = chaininfo->nentries;
 286		point = (struct ebt_entry *)chaininfo->data;
 287		counter_base = cb_base + chaininfo->counter_offset;
 288		sp++;
 289		continue;
 290letscontinue:
 291		point = ebt_next_entry(point);
 292		i++;
 293	}
 294
 295	/* I actually like this :) */
 296	if (chaininfo->policy == EBT_RETURN)
 297		goto letsreturn;
 298	if (chaininfo->policy == EBT_ACCEPT) {
 299		read_unlock_bh(&table->lock);
 300		return NF_ACCEPT;
 301	}
 302	read_unlock_bh(&table->lock);
 303	return NF_DROP;
 304}
 305
 306/* If it succeeds, returns element and locks mutex */
 307static inline void *
 308find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
 309			struct mutex *mutex)
 310{
 311	struct {
 312		struct list_head list;
 313		char name[EBT_FUNCTION_MAXNAMELEN];
 314	} *e;
 315
 316	mutex_lock(mutex);
 317	list_for_each_entry(e, head, list) {
 318		if (strcmp(e->name, name) == 0)
 319			return e;
 320	}
 321	*error = -ENOENT;
 322	mutex_unlock(mutex);
 323	return NULL;
 324}
 325
 326static void *
 327find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
 328		 int *error, struct mutex *mutex)
 329{
 330	return try_then_request_module(
 331			find_inlist_lock_noload(head, name, error, mutex),
 332			"%s%s", prefix, name);
 333}
 334
 335static inline struct ebt_table *
 336find_table_lock(struct net *net, const char *name, int *error,
 337		struct mutex *mutex)
 338{
 339	return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
 340				"ebtable_", error, mutex);
 341}
 342
 343static inline void ebt_free_table_info(struct ebt_table_info *info)
 344{
 345	int i;
 346
 347	if (info->chainstack) {
 348		for_each_possible_cpu(i)
 349			vfree(info->chainstack[i]);
 350		vfree(info->chainstack);
 351	}
 352}
 353static inline int
 354ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
 355		unsigned int *cnt)
 356{
 357	const struct ebt_entry *e = par->entryinfo;
 358	struct xt_match *match;
 359	size_t left = ((char *)e + e->watchers_offset) - (char *)m;
 360	int ret;
 361
 362	if (left < sizeof(struct ebt_entry_match) ||
 363	    left - sizeof(struct ebt_entry_match) < m->match_size)
 364		return -EINVAL;
 365
 366	match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 367	if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
 368		if (!IS_ERR(match))
 369			module_put(match->me);
 370		request_module("ebt_%s", m->u.name);
 371		match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
 372	}
 373	if (IS_ERR(match))
 374		return PTR_ERR(match);
 375	m->u.match = match;
 376
 377	par->match     = match;
 378	par->matchinfo = m->data;
 379	ret = xt_check_match(par, m->match_size,
 380	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 381	if (ret < 0) {
 382		module_put(match->me);
 383		return ret;
 384	}
 385
 386	(*cnt)++;
 387	return 0;
 388}
 389
 390static inline int
 391ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
 392		  unsigned int *cnt)
 393{
 394	const struct ebt_entry *e = par->entryinfo;
 395	struct xt_target *watcher;
 396	size_t left = ((char *)e + e->target_offset) - (char *)w;
 397	int ret;
 398
 399	if (left < sizeof(struct ebt_entry_watcher) ||
 400	   left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
 401		return -EINVAL;
 402
 403	watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
 404	if (IS_ERR(watcher))
 405		return PTR_ERR(watcher);
 406
 407	if (watcher->family != NFPROTO_BRIDGE) {
 408		module_put(watcher->me);
 409		return -ENOENT;
 410	}
 411
 412	w->u.watcher = watcher;
 413
 414	par->target   = watcher;
 415	par->targinfo = w->data;
 416	ret = xt_check_target(par, w->watcher_size,
 417	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 418	if (ret < 0) {
 419		module_put(watcher->me);
 420		return ret;
 421	}
 422
 423	(*cnt)++;
 424	return 0;
 425}
 426
 427static int ebt_verify_pointers(const struct ebt_replace *repl,
 428			       struct ebt_table_info *newinfo)
 429{
 430	unsigned int limit = repl->entries_size;
 431	unsigned int valid_hooks = repl->valid_hooks;
 432	unsigned int offset = 0;
 433	int i;
 434
 435	for (i = 0; i < NF_BR_NUMHOOKS; i++)
 436		newinfo->hook_entry[i] = NULL;
 437
 438	newinfo->entries_size = repl->entries_size;
 439	newinfo->nentries = repl->nentries;
 440
 441	while (offset < limit) {
 442		size_t left = limit - offset;
 443		struct ebt_entry *e = (void *)newinfo->entries + offset;
 444
 445		if (left < sizeof(unsigned int))
 446			break;
 447
 448		for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 449			if ((valid_hooks & (1 << i)) == 0)
 450				continue;
 451			if ((char __user *)repl->hook_entry[i] ==
 452			     repl->entries + offset)
 453				break;
 454		}
 455
 456		if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
 457			if (e->bitmask != 0) {
 458				/* we make userspace set this right,
 459				 * so there is no misunderstanding
 460				 */
 461				return -EINVAL;
 462			}
 463			if (i != NF_BR_NUMHOOKS)
 464				newinfo->hook_entry[i] = (struct ebt_entries *)e;
 465			if (left < sizeof(struct ebt_entries))
 466				break;
 467			offset += sizeof(struct ebt_entries);
 468		} else {
 469			if (left < sizeof(struct ebt_entry))
 470				break;
 471			if (left < e->next_offset)
 472				break;
 473			if (e->next_offset < sizeof(struct ebt_entry))
 474				return -EINVAL;
 475			offset += e->next_offset;
 476		}
 477	}
 478	if (offset != limit)
 479		return -EINVAL;
 480
 481	/* check if all valid hooks have a chain */
 482	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 483		if (!newinfo->hook_entry[i] &&
 484		   (valid_hooks & (1 << i)))
 485			return -EINVAL;
 486	}
 487	return 0;
 488}
 489
 490/* this one is very careful, as it is the first function
 491 * to parse the userspace data
 492 */
 493static inline int
 494ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
 495			       const struct ebt_table_info *newinfo,
 496			       unsigned int *n, unsigned int *cnt,
 497			       unsigned int *totalcnt, unsigned int *udc_cnt)
 498{
 499	int i;
 500
 501	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 502		if ((void *)e == (void *)newinfo->hook_entry[i])
 503			break;
 504	}
 505	/* beginning of a new chain
 506	 * if i == NF_BR_NUMHOOKS it must be a user defined chain
 507	 */
 508	if (i != NF_BR_NUMHOOKS || !e->bitmask) {
 509		/* this checks if the previous chain has as many entries
 510		 * as it said it has
 511		 */
 512		if (*n != *cnt)
 513			return -EINVAL;
 514
 515		if (((struct ebt_entries *)e)->policy != EBT_DROP &&
 516		   ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
 517			/* only RETURN from udc */
 518			if (i != NF_BR_NUMHOOKS ||
 519			   ((struct ebt_entries *)e)->policy != EBT_RETURN)
 520				return -EINVAL;
 521		}
 522		if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
 523			(*udc_cnt)++;
 524		if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
 525			return -EINVAL;
 526		*n = ((struct ebt_entries *)e)->nentries;
 527		*cnt = 0;
 528		return 0;
 529	}
 530	/* a plain old entry, heh */
 531	if (sizeof(struct ebt_entry) > e->watchers_offset ||
 532	   e->watchers_offset > e->target_offset ||
 533	   e->target_offset >= e->next_offset)
 534		return -EINVAL;
 535
 536	/* this is not checked anywhere else */
 537	if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
 538		return -EINVAL;
 539
 540	(*cnt)++;
 541	(*totalcnt)++;
 542	return 0;
 543}
 544
 545struct ebt_cl_stack {
 546	struct ebt_chainstack cs;
 547	int from;
 548	unsigned int hookmask;
 549};
 550
 551/* We need these positions to check that the jumps to a different part of the
 552 * entries is a jump to the beginning of a new chain.
 553 */
 554static inline int
 555ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
 556		      unsigned int *n, struct ebt_cl_stack *udc)
 557{
 558	int i;
 559
 560	/* we're only interested in chain starts */
 561	if (e->bitmask)
 562		return 0;
 563	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 564		if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
 565			break;
 566	}
 567	/* only care about udc */
 568	if (i != NF_BR_NUMHOOKS)
 569		return 0;
 570
 571	udc[*n].cs.chaininfo = (struct ebt_entries *)e;
 572	/* these initialisations are depended on later in check_chainloops() */
 573	udc[*n].cs.n = 0;
 574	udc[*n].hookmask = 0;
 575
 576	(*n)++;
 577	return 0;
 578}
 579
 580static inline int
 581ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
 582{
 583	struct xt_mtdtor_param par;
 584
 585	if (i && (*i)-- == 0)
 586		return 1;
 587
 588	par.net       = net;
 589	par.match     = m->u.match;
 590	par.matchinfo = m->data;
 591	par.family    = NFPROTO_BRIDGE;
 592	if (par.match->destroy != NULL)
 593		par.match->destroy(&par);
 594	module_put(par.match->me);
 595	return 0;
 596}
 597
 598static inline int
 599ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
 600{
 601	struct xt_tgdtor_param par;
 602
 603	if (i && (*i)-- == 0)
 604		return 1;
 605
 606	par.net      = net;
 607	par.target   = w->u.watcher;
 608	par.targinfo = w->data;
 609	par.family   = NFPROTO_BRIDGE;
 610	if (par.target->destroy != NULL)
 611		par.target->destroy(&par);
 612	module_put(par.target->me);
 613	return 0;
 614}
 615
 616static inline int
 617ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
 618{
 619	struct xt_tgdtor_param par;
 620	struct ebt_entry_target *t;
 621
 622	if (e->bitmask == 0)
 623		return 0;
 624	/* we're done */
 625	if (cnt && (*cnt)-- == 0)
 626		return 1;
 627	EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
 628	EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
 629	t = ebt_get_target(e);
 630
 631	par.net      = net;
 632	par.target   = t->u.target;
 633	par.targinfo = t->data;
 634	par.family   = NFPROTO_BRIDGE;
 635	if (par.target->destroy != NULL)
 636		par.target->destroy(&par);
 637	module_put(par.target->me);
 638	return 0;
 639}
 640
 641static inline int
 642ebt_check_entry(struct ebt_entry *e, struct net *net,
 643		const struct ebt_table_info *newinfo,
 644		const char *name, unsigned int *cnt,
 645		struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
 646{
 647	struct ebt_entry_target *t;
 648	struct xt_target *target;
 649	unsigned int i, j, hook = 0, hookmask = 0;
 650	size_t gap;
 651	int ret;
 652	struct xt_mtchk_param mtpar;
 653	struct xt_tgchk_param tgpar;
 654
 655	/* don't mess with the struct ebt_entries */
 656	if (e->bitmask == 0)
 657		return 0;
 658
 659	if (e->bitmask & ~EBT_F_MASK)
 660		return -EINVAL;
 661
 662	if (e->invflags & ~EBT_INV_MASK)
 663		return -EINVAL;
 664
 665	if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
 666		return -EINVAL;
 667
 668	/* what hook do we belong to? */
 669	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
 670		if (!newinfo->hook_entry[i])
 671			continue;
 672		if ((char *)newinfo->hook_entry[i] < (char *)e)
 673			hook = i;
 674		else
 675			break;
 676	}
 677	/* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
 678	 * a base chain
 679	 */
 680	if (i < NF_BR_NUMHOOKS)
 681		hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 682	else {
 683		for (i = 0; i < udc_cnt; i++)
 684			if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
 685				break;
 686		if (i == 0)
 687			hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
 688		else
 689			hookmask = cl_s[i - 1].hookmask;
 690	}
 691	i = 0;
 692
 693	memset(&mtpar, 0, sizeof(mtpar));
 694	memset(&tgpar, 0, sizeof(tgpar));
 695	mtpar.net	= tgpar.net       = net;
 696	mtpar.table     = tgpar.table     = name;
 697	mtpar.entryinfo = tgpar.entryinfo = e;
 698	mtpar.hook_mask = tgpar.hook_mask = hookmask;
 699	mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
 700	ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
 701	if (ret != 0)
 702		goto cleanup_matches;
 703	j = 0;
 704	ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
 705	if (ret != 0)
 706		goto cleanup_watchers;
 707	t = ebt_get_target(e);
 708	gap = e->next_offset - e->target_offset;
 709
 710	target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
 711	if (IS_ERR(target)) {
 712		ret = PTR_ERR(target);
 713		goto cleanup_watchers;
 714	}
 715
 716	/* Reject UNSPEC, xtables verdicts/return values are incompatible */
 717	if (target->family != NFPROTO_BRIDGE) {
 718		module_put(target->me);
 719		ret = -ENOENT;
 720		goto cleanup_watchers;
 721	}
 722
 723	t->u.target = target;
 724	if (t->u.target == &ebt_standard_target) {
 725		if (gap < sizeof(struct ebt_standard_target)) {
 726			ret = -EFAULT;
 727			goto cleanup_watchers;
 728		}
 729		if (((struct ebt_standard_target *)t)->verdict <
 730		   -NUM_STANDARD_TARGETS) {
 731			ret = -EFAULT;
 732			goto cleanup_watchers;
 733		}
 734	} else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
 735		module_put(t->u.target->me);
 736		ret = -EFAULT;
 737		goto cleanup_watchers;
 738	}
 739
 740	tgpar.target   = target;
 741	tgpar.targinfo = t->data;
 742	ret = xt_check_target(&tgpar, t->target_size,
 743	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 744	if (ret < 0) {
 745		module_put(target->me);
 746		goto cleanup_watchers;
 747	}
 748	(*cnt)++;
 749	return 0;
 750cleanup_watchers:
 751	EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
 752cleanup_matches:
 753	EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
 754	return ret;
 755}
 756
 757/* checks for loops and sets the hook mask for udc
 758 * the hook mask for udc tells us from which base chains the udc can be
 759 * accessed. This mask is a parameter to the check() functions of the extensions
 760 */
 761static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
 762			    unsigned int udc_cnt, unsigned int hooknr, char *base)
 763{
 764	int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
 765	const struct ebt_entry *e = (struct ebt_entry *)chain->data;
 766	const struct ebt_entry_target *t;
 767
 768	while (pos < nentries || chain_nr != -1) {
 769		/* end of udc, go back one 'recursion' step */
 770		if (pos == nentries) {
 771			/* put back values of the time when this chain was called */
 772			e = cl_s[chain_nr].cs.e;
 773			if (cl_s[chain_nr].from != -1)
 774				nentries =
 775				cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
 776			else
 777				nentries = chain->nentries;
 778			pos = cl_s[chain_nr].cs.n;
 779			/* make sure we won't see a loop that isn't one */
 780			cl_s[chain_nr].cs.n = 0;
 781			chain_nr = cl_s[chain_nr].from;
 782			if (pos == nentries)
 783				continue;
 784		}
 785		t = ebt_get_target_c(e);
 786		if (strcmp(t->u.name, EBT_STANDARD_TARGET))
 787			goto letscontinue;
 788		if (e->target_offset + sizeof(struct ebt_standard_target) >
 789		   e->next_offset)
 790			return -1;
 791
 792		verdict = ((struct ebt_standard_target *)t)->verdict;
 793		if (verdict >= 0) { /* jump to another chain */
 794			struct ebt_entries *hlp2 =
 795			   (struct ebt_entries *)(base + verdict);
 796			for (i = 0; i < udc_cnt; i++)
 797				if (hlp2 == cl_s[i].cs.chaininfo)
 798					break;
 799			/* bad destination or loop */
 800			if (i == udc_cnt)
 801				return -1;
 802
 803			if (cl_s[i].cs.n)
 804				return -1;
 805
 806			if (cl_s[i].hookmask & (1 << hooknr))
 807				goto letscontinue;
 808			/* this can't be 0, so the loop test is correct */
 809			cl_s[i].cs.n = pos + 1;
 810			pos = 0;
 811			cl_s[i].cs.e = ebt_next_entry(e);
 812			e = (struct ebt_entry *)(hlp2->data);
 813			nentries = hlp2->nentries;
 814			cl_s[i].from = chain_nr;
 815			chain_nr = i;
 816			/* this udc is accessible from the base chain for hooknr */
 817			cl_s[i].hookmask |= (1 << hooknr);
 818			continue;
 819		}
 820letscontinue:
 821		e = ebt_next_entry(e);
 822		pos++;
 823	}
 824	return 0;
 825}
 826
 827/* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
 828static int translate_table(struct net *net, const char *name,
 829			   struct ebt_table_info *newinfo)
 830{
 831	unsigned int i, j, k, udc_cnt;
 832	int ret;
 833	struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
 834
 835	i = 0;
 836	while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
 837		i++;
 838	if (i == NF_BR_NUMHOOKS)
 839		return -EINVAL;
 840
 841	if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
 842		return -EINVAL;
 843
 844	/* make sure chains are ordered after each other in same order
 845	 * as their corresponding hooks
 846	 */
 847	for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
 848		if (!newinfo->hook_entry[j])
 849			continue;
 850		if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
 851			return -EINVAL;
 852
 853		i = j;
 854	}
 855
 856	/* do some early checkings and initialize some things */
 857	i = 0; /* holds the expected nr. of entries for the chain */
 858	j = 0; /* holds the up to now counted entries for the chain */
 859	k = 0; /* holds the total nr. of entries, should equal
 860		* newinfo->nentries afterwards
 861		*/
 862	udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
 863	ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 864	   ebt_check_entry_size_and_hooks, newinfo,
 865	   &i, &j, &k, &udc_cnt);
 866
 867	if (ret != 0)
 868		return ret;
 869
 870	if (i != j)
 871		return -EINVAL;
 872
 873	if (k != newinfo->nentries)
 874		return -EINVAL;
 875
 876	/* get the location of the udc, put them in an array
 877	 * while we're at it, allocate the chainstack
 878	 */
 879	if (udc_cnt) {
 880		/* this will get free'd in do_replace()/ebt_register_table()
 881		 * if an error occurs
 882		 */
 883		newinfo->chainstack =
 884			vmalloc(array_size(nr_cpu_ids,
 885					   sizeof(*(newinfo->chainstack))));
 886		if (!newinfo->chainstack)
 887			return -ENOMEM;
 888		for_each_possible_cpu(i) {
 889			newinfo->chainstack[i] =
 890			  vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0]))));
 891			if (!newinfo->chainstack[i]) {
 892				while (i)
 893					vfree(newinfo->chainstack[--i]);
 894				vfree(newinfo->chainstack);
 895				newinfo->chainstack = NULL;
 896				return -ENOMEM;
 897			}
 898		}
 899
 900		cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
 901		if (!cl_s)
 902			return -ENOMEM;
 903		i = 0; /* the i'th udc */
 904		EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 905		   ebt_get_udc_positions, newinfo, &i, cl_s);
 906		/* sanity check */
 907		if (i != udc_cnt) {
 908			vfree(cl_s);
 909			return -EFAULT;
 910		}
 911	}
 912
 913	/* Check for loops */
 914	for (i = 0; i < NF_BR_NUMHOOKS; i++)
 915		if (newinfo->hook_entry[i])
 916			if (check_chainloops(newinfo->hook_entry[i],
 917			   cl_s, udc_cnt, i, newinfo->entries)) {
 918				vfree(cl_s);
 919				return -EINVAL;
 920			}
 921
 922	/* we now know the following (along with E=mc²):
 923	 *  - the nr of entries in each chain is right
 924	 *  - the size of the allocated space is right
 925	 *  - all valid hooks have a corresponding chain
 926	 *  - there are no loops
 927	 *  - wrong data can still be on the level of a single entry
 928	 *  - could be there are jumps to places that are not the
 929	 *    beginning of a chain. This can only occur in chains that
 930	 *    are not accessible from any base chains, so we don't care.
 931	 */
 932
 933	/* used to know what we need to clean up if something goes wrong */
 934	i = 0;
 935	ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 936	   ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
 937	if (ret != 0) {
 938		EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
 939				  ebt_cleanup_entry, net, &i);
 940	}
 941	vfree(cl_s);
 942	return ret;
 943}
 944
 945/* called under write_lock */
 946static void get_counters(const struct ebt_counter *oldcounters,
 947			 struct ebt_counter *counters, unsigned int nentries)
 948{
 949	int i, cpu;
 950	struct ebt_counter *counter_base;
 951
 952	/* counters of cpu 0 */
 953	memcpy(counters, oldcounters,
 954	       sizeof(struct ebt_counter) * nentries);
 955
 956	/* add other counters to those of cpu 0 */
 957	for_each_possible_cpu(cpu) {
 958		if (cpu == 0)
 959			continue;
 960		counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
 961		for (i = 0; i < nentries; i++)
 962			ADD_COUNTER(counters[i], counter_base[i].bcnt,
 963				    counter_base[i].pcnt);
 964	}
 965}
 966
 967static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 968			      struct ebt_table_info *newinfo)
 969{
 970	int ret;
 971	struct ebt_counter *counterstmp = NULL;
 972	/* used to be able to unlock earlier */
 973	struct ebt_table_info *table;
 974	struct ebt_table *t;
 975
 976	/* the user wants counters back
 977	 * the check on the size is done later, when we have the lock
 978	 */
 979	if (repl->num_counters) {
 980		unsigned long size = repl->num_counters * sizeof(*counterstmp);
 981		counterstmp = vmalloc(size);
 982		if (!counterstmp)
 983			return -ENOMEM;
 984	}
 985
 986	newinfo->chainstack = NULL;
 987	ret = ebt_verify_pointers(repl, newinfo);
 988	if (ret != 0)
 989		goto free_counterstmp;
 990
 991	ret = translate_table(net, repl->name, newinfo);
 992
 993	if (ret != 0)
 994		goto free_counterstmp;
 995
 996	t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
 997	if (!t) {
 998		ret = -ENOENT;
 999		goto free_iterate;
1000	}
1001
1002	/* the table doesn't like it */
1003	if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1004		goto free_unlock;
1005
1006	if (repl->num_counters && repl->num_counters != t->private->nentries) {
1007		ret = -EINVAL;
1008		goto free_unlock;
1009	}
1010
1011	/* we have the mutex lock, so no danger in reading this pointer */
1012	table = t->private;
1013	/* make sure the table can only be rmmod'ed if it contains no rules */
1014	if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1015		ret = -ENOENT;
1016		goto free_unlock;
1017	} else if (table->nentries && !newinfo->nentries)
1018		module_put(t->me);
1019	/* we need an atomic snapshot of the counters */
1020	write_lock_bh(&t->lock);
1021	if (repl->num_counters)
1022		get_counters(t->private->counters, counterstmp,
1023		   t->private->nentries);
1024
1025	t->private = newinfo;
1026	write_unlock_bh(&t->lock);
1027	mutex_unlock(&ebt_mutex);
1028	/* so, a user can change the chains while having messed up her counter
1029	 * allocation. Only reason why this is done is because this way the lock
1030	 * is held only once, while this doesn't bring the kernel into a
1031	 * dangerous state.
1032	 */
1033	if (repl->num_counters &&
1034	   copy_to_user(repl->counters, counterstmp,
1035	   repl->num_counters * sizeof(struct ebt_counter))) {
1036		/* Silent error, can't fail, new table is already in place */
1037		net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1038	}
1039
1040	/* decrease module count and free resources */
1041	EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1042			  ebt_cleanup_entry, net, NULL);
1043
1044	vfree(table->entries);
1045	ebt_free_table_info(table);
1046	vfree(table);
1047	vfree(counterstmp);
1048
1049#ifdef CONFIG_AUDIT
1050	if (audit_enabled) {
1051		audit_log(audit_context(), GFP_KERNEL,
1052			  AUDIT_NETFILTER_CFG,
1053			  "table=%s family=%u entries=%u",
1054			  repl->name, AF_BRIDGE, repl->nentries);
1055	}
1056#endif
1057	return ret;
1058
1059free_unlock:
1060	mutex_unlock(&ebt_mutex);
1061free_iterate:
1062	EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1063			  ebt_cleanup_entry, net, NULL);
1064free_counterstmp:
1065	vfree(counterstmp);
1066	/* can be initialized in translate_table() */
1067	ebt_free_table_info(newinfo);
1068	return ret;
1069}
1070
1071/* replace the table */
1072static int do_replace(struct net *net, const void __user *user,
1073		      unsigned int len)
1074{
1075	int ret, countersize;
1076	struct ebt_table_info *newinfo;
1077	struct ebt_replace tmp;
1078
1079	if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1080		return -EFAULT;
1081
1082	if (len != sizeof(tmp) + tmp.entries_size)
1083		return -EINVAL;
1084
1085	if (tmp.entries_size == 0)
1086		return -EINVAL;
1087
1088	/* overflow check */
1089	if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1090			NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1091		return -ENOMEM;
1092	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1093		return -ENOMEM;
1094
1095	tmp.name[sizeof(tmp.name) - 1] = 0;
1096
1097	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1098	newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT,
1099			    PAGE_KERNEL);
1100	if (!newinfo)
1101		return -ENOMEM;
1102
1103	if (countersize)
1104		memset(newinfo->counters, 0, countersize);
1105
1106	newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT,
1107				     PAGE_KERNEL);
1108	if (!newinfo->entries) {
1109		ret = -ENOMEM;
1110		goto free_newinfo;
1111	}
1112	if (copy_from_user(
1113	   newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1114		ret = -EFAULT;
1115		goto free_entries;
1116	}
1117
1118	ret = do_replace_finish(net, &tmp, newinfo);
1119	if (ret == 0)
1120		return ret;
1121free_entries:
1122	vfree(newinfo->entries);
1123free_newinfo:
1124	vfree(newinfo);
1125	return ret;
1126}
1127
1128static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1129{
1130	mutex_lock(&ebt_mutex);
1131	list_del(&table->list);
1132	mutex_unlock(&ebt_mutex);
1133	EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1134			  ebt_cleanup_entry, net, NULL);
1135	if (table->private->nentries)
1136		module_put(table->me);
1137	vfree(table->private->entries);
1138	ebt_free_table_info(table->private);
1139	vfree(table->private);
1140	kfree(table);
1141}
1142
1143int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1144		       const struct nf_hook_ops *ops, struct ebt_table **res)
1145{
1146	struct ebt_table_info *newinfo;
1147	struct ebt_table *t, *table;
1148	struct ebt_replace_kernel *repl;
1149	int ret, i, countersize;
1150	void *p;
1151
1152	if (input_table == NULL || (repl = input_table->table) == NULL ||
1153	    repl->entries == NULL || repl->entries_size == 0 ||
1154	    repl->counters != NULL || input_table->private != NULL)
1155		return -EINVAL;
1156
1157	/* Don't add one table to multiple lists. */
1158	table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1159	if (!table) {
1160		ret = -ENOMEM;
1161		goto out;
1162	}
1163
1164	countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1165	newinfo = vmalloc(sizeof(*newinfo) + countersize);
1166	ret = -ENOMEM;
1167	if (!newinfo)
1168		goto free_table;
1169
1170	p = vmalloc(repl->entries_size);
1171	if (!p)
1172		goto free_newinfo;
1173
1174	memcpy(p, repl->entries, repl->entries_size);
1175	newinfo->entries = p;
1176
1177	newinfo->entries_size = repl->entries_size;
1178	newinfo->nentries = repl->nentries;
1179
1180	if (countersize)
1181		memset(newinfo->counters, 0, countersize);
1182
1183	/* fill in newinfo and parse the entries */
1184	newinfo->chainstack = NULL;
1185	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1186		if ((repl->valid_hooks & (1 << i)) == 0)
1187			newinfo->hook_entry[i] = NULL;
1188		else
1189			newinfo->hook_entry[i] = p +
1190				((char *)repl->hook_entry[i] - repl->entries);
1191	}
1192	ret = translate_table(net, repl->name, newinfo);
1193	if (ret != 0)
1194		goto free_chainstack;
1195
1196	if (table->check && table->check(newinfo, table->valid_hooks)) {
1197		ret = -EINVAL;
1198		goto free_chainstack;
1199	}
1200
1201	table->private = newinfo;
1202	rwlock_init(&table->lock);
1203	mutex_lock(&ebt_mutex);
1204	list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1205		if (strcmp(t->name, table->name) == 0) {
1206			ret = -EEXIST;
1207			goto free_unlock;
1208		}
1209	}
1210
1211	/* Hold a reference count if the chains aren't empty */
1212	if (newinfo->nentries && !try_module_get(table->me)) {
1213		ret = -ENOENT;
1214		goto free_unlock;
1215	}
1216	list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1217	mutex_unlock(&ebt_mutex);
1218
1219	WRITE_ONCE(*res, table);
1220	ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1221	if (ret) {
1222		__ebt_unregister_table(net, table);
1223		*res = NULL;
1224	}
1225
1226	return ret;
1227free_unlock:
1228	mutex_unlock(&ebt_mutex);
1229free_chainstack:
1230	ebt_free_table_info(newinfo);
1231	vfree(newinfo->entries);
1232free_newinfo:
1233	vfree(newinfo);
1234free_table:
1235	kfree(table);
1236out:
1237	return ret;
1238}
1239
1240void ebt_unregister_table(struct net *net, struct ebt_table *table,
1241			  const struct nf_hook_ops *ops)
1242{
1243	nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1244	__ebt_unregister_table(net, table);
1245}
1246
1247/* userspace just supplied us with counters */
1248static int do_update_counters(struct net *net, const char *name,
1249				struct ebt_counter __user *counters,
1250				unsigned int num_counters,
1251				const void __user *user, unsigned int len)
1252{
1253	int i, ret;
1254	struct ebt_counter *tmp;
1255	struct ebt_table *t;
1256
1257	if (num_counters == 0)
1258		return -EINVAL;
1259
1260	tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1261	if (!tmp)
1262		return -ENOMEM;
1263
1264	t = find_table_lock(net, name, &ret, &ebt_mutex);
1265	if (!t)
1266		goto free_tmp;
1267
1268	if (num_counters != t->private->nentries) {
1269		ret = -EINVAL;
1270		goto unlock_mutex;
1271	}
1272
1273	if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1274		ret = -EFAULT;
1275		goto unlock_mutex;
1276	}
1277
1278	/* we want an atomic add of the counters */
1279	write_lock_bh(&t->lock);
1280
1281	/* we add to the counters of the first cpu */
1282	for (i = 0; i < num_counters; i++)
1283		ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1284
1285	write_unlock_bh(&t->lock);
1286	ret = 0;
1287unlock_mutex:
1288	mutex_unlock(&ebt_mutex);
1289free_tmp:
1290	vfree(tmp);
1291	return ret;
1292}
1293
1294static int update_counters(struct net *net, const void __user *user,
1295			    unsigned int len)
1296{
1297	struct ebt_replace hlp;
1298
1299	if (copy_from_user(&hlp, user, sizeof(hlp)))
1300		return -EFAULT;
1301
1302	if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1303		return -EINVAL;
1304
1305	return do_update_counters(net, hlp.name, hlp.counters,
1306				hlp.num_counters, user, len);
1307}
1308
1309static inline int ebt_obj_to_user(char __user *um, const char *_name,
1310				  const char *data, int entrysize,
1311				  int usersize, int datasize, u8 revision)
1312{
1313	char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1314
1315	/* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1316	 * long. Copy 29 bytes and fill remaining bytes with zeroes.
1317	 */
1318	strlcpy(name, _name, sizeof(name));
1319	if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1320	    put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1321	    put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1322	    xt_data_to_user(um + entrysize, data, usersize, datasize,
1323			    XT_ALIGN(datasize)))
1324		return -EFAULT;
1325
1326	return 0;
1327}
1328
1329static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1330				    const char *base, char __user *ubase)
1331{
1332	return ebt_obj_to_user(ubase + ((char *)m - base),
1333			       m->u.match->name, m->data, sizeof(*m),
1334			       m->u.match->usersize, m->match_size,
1335			       m->u.match->revision);
1336}
1337
1338static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1339				      const char *base, char __user *ubase)
1340{
1341	return ebt_obj_to_user(ubase + ((char *)w - base),
1342			       w->u.watcher->name, w->data, sizeof(*w),
1343			       w->u.watcher->usersize, w->watcher_size,
1344			       w->u.watcher->revision);
1345}
1346
1347static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1348				    char __user *ubase)
1349{
1350	int ret;
1351	char __user *hlp;
1352	const struct ebt_entry_target *t;
1353
1354	if (e->bitmask == 0) {
1355		/* special case !EBT_ENTRY_OR_ENTRIES */
1356		if (copy_to_user(ubase + ((char *)e - base), e,
1357				 sizeof(struct ebt_entries)))
1358			return -EFAULT;
1359		return 0;
1360	}
1361
1362	if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1363		return -EFAULT;
1364
1365	hlp = ubase + (((char *)e + e->target_offset) - base);
1366	t = ebt_get_target_c(e);
1367
1368	ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1369	if (ret != 0)
1370		return ret;
1371	ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1372	if (ret != 0)
1373		return ret;
1374	ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1375			      t->u.target->usersize, t->target_size,
1376			      t->u.target->revision);
1377	if (ret != 0)
1378		return ret;
1379
1380	return 0;
1381}
1382
1383static int copy_counters_to_user(struct ebt_table *t,
1384				 const struct ebt_counter *oldcounters,
1385				 void __user *user, unsigned int num_counters,
1386				 unsigned int nentries)
1387{
1388	struct ebt_counter *counterstmp;
1389	int ret = 0;
1390
1391	/* userspace might not need the counters */
1392	if (num_counters == 0)
1393		return 0;
1394
1395	if (num_counters != nentries)
1396		return -EINVAL;
1397
1398	counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1399	if (!counterstmp)
1400		return -ENOMEM;
1401
1402	write_lock_bh(&t->lock);
1403	get_counters(oldcounters, counterstmp, nentries);
1404	write_unlock_bh(&t->lock);
1405
1406	if (copy_to_user(user, counterstmp,
1407	   nentries * sizeof(struct ebt_counter)))
1408		ret = -EFAULT;
1409	vfree(counterstmp);
1410	return ret;
1411}
1412
1413/* called with ebt_mutex locked */
1414static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1415				   const int *len, int cmd)
1416{
1417	struct ebt_replace tmp;
1418	const struct ebt_counter *oldcounters;
1419	unsigned int entries_size, nentries;
1420	int ret;
1421	char *entries;
1422
1423	if (cmd == EBT_SO_GET_ENTRIES) {
1424		entries_size = t->private->entries_size;
1425		nentries = t->private->nentries;
1426		entries = t->private->entries;
1427		oldcounters = t->private->counters;
1428	} else {
1429		entries_size = t->table->entries_size;
1430		nentries = t->table->nentries;
1431		entries = t->table->entries;
1432		oldcounters = t->table->counters;
1433	}
1434
1435	if (copy_from_user(&tmp, user, sizeof(tmp)))
1436		return -EFAULT;
1437
1438	if (*len != sizeof(struct ebt_replace) + entries_size +
1439	   (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1440		return -EINVAL;
1441
1442	if (tmp.nentries != nentries)
1443		return -EINVAL;
1444
1445	if (tmp.entries_size != entries_size)
1446		return -EINVAL;
1447
1448	ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1449					tmp.num_counters, nentries);
1450	if (ret)
1451		return ret;
1452
1453	/* set the match/watcher/target names right */
1454	return EBT_ENTRY_ITERATE(entries, entries_size,
1455	   ebt_entry_to_user, entries, tmp.entries);
1456}
1457
1458static int do_ebt_set_ctl(struct sock *sk,
1459	int cmd, void __user *user, unsigned int len)
1460{
1461	int ret;
1462	struct net *net = sock_net(sk);
1463
1464	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1465		return -EPERM;
1466
1467	switch (cmd) {
1468	case EBT_SO_SET_ENTRIES:
1469		ret = do_replace(net, user, len);
1470		break;
1471	case EBT_SO_SET_COUNTERS:
1472		ret = update_counters(net, user, len);
1473		break;
1474	default:
1475		ret = -EINVAL;
1476	}
1477	return ret;
1478}
1479
1480static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1481{
1482	int ret;
1483	struct ebt_replace tmp;
1484	struct ebt_table *t;
1485	struct net *net = sock_net(sk);
1486
1487	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1488		return -EPERM;
1489
1490	if (copy_from_user(&tmp, user, sizeof(tmp)))
1491		return -EFAULT;
1492
1493	tmp.name[sizeof(tmp.name) - 1] = '\0';
1494
1495	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1496	if (!t)
1497		return ret;
1498
1499	switch (cmd) {
1500	case EBT_SO_GET_INFO:
1501	case EBT_SO_GET_INIT_INFO:
1502		if (*len != sizeof(struct ebt_replace)) {
1503			ret = -EINVAL;
1504			mutex_unlock(&ebt_mutex);
1505			break;
1506		}
1507		if (cmd == EBT_SO_GET_INFO) {
1508			tmp.nentries = t->private->nentries;
1509			tmp.entries_size = t->private->entries_size;
1510			tmp.valid_hooks = t->valid_hooks;
1511		} else {
1512			tmp.nentries = t->table->nentries;
1513			tmp.entries_size = t->table->entries_size;
1514			tmp.valid_hooks = t->table->valid_hooks;
1515		}
1516		mutex_unlock(&ebt_mutex);
1517		if (copy_to_user(user, &tmp, *len) != 0) {
1518			ret = -EFAULT;
1519			break;
1520		}
1521		ret = 0;
1522		break;
1523
1524	case EBT_SO_GET_ENTRIES:
1525	case EBT_SO_GET_INIT_ENTRIES:
1526		ret = copy_everything_to_user(t, user, len, cmd);
1527		mutex_unlock(&ebt_mutex);
1528		break;
1529
1530	default:
1531		mutex_unlock(&ebt_mutex);
1532		ret = -EINVAL;
1533	}
1534
1535	return ret;
1536}
1537
1538#ifdef CONFIG_COMPAT
1539/* 32 bit-userspace compatibility definitions. */
1540struct compat_ebt_replace {
1541	char name[EBT_TABLE_MAXNAMELEN];
1542	compat_uint_t valid_hooks;
1543	compat_uint_t nentries;
1544	compat_uint_t entries_size;
1545	/* start of the chains */
1546	compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1547	/* nr of counters userspace expects back */
1548	compat_uint_t num_counters;
1549	/* where the kernel will put the old counters. */
1550	compat_uptr_t counters;
1551	compat_uptr_t entries;
1552};
1553
1554/* struct ebt_entry_match, _target and _watcher have same layout */
1555struct compat_ebt_entry_mwt {
1556	union {
1557		struct {
1558			char name[EBT_EXTENSION_MAXNAMELEN];
1559			u8 revision;
1560		};
1561		compat_uptr_t ptr;
1562	} u;
1563	compat_uint_t match_size;
1564	compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1565};
1566
1567/* account for possible padding between match_size and ->data */
1568static int ebt_compat_entry_padsize(void)
1569{
1570	BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1571			sizeof(struct compat_ebt_entry_mwt));
1572	return (int) sizeof(struct ebt_entry_match) -
1573			sizeof(struct compat_ebt_entry_mwt);
1574}
1575
1576static int ebt_compat_match_offset(const struct xt_match *match,
1577				   unsigned int userlen)
1578{
1579	/* ebt_among needs special handling. The kernel .matchsize is
1580	 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1581	 * value is expected.
1582	 * Example: userspace sends 4500, ebt_among.c wants 4504.
1583	 */
1584	if (unlikely(match->matchsize == -1))
1585		return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1586	return xt_compat_match_offset(match);
1587}
1588
1589static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1590				unsigned int *size)
1591{
1592	const struct xt_match *match = m->u.match;
1593	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1594	int off = ebt_compat_match_offset(match, m->match_size);
1595	compat_uint_t msize = m->match_size - off;
1596
1597	if (WARN_ON(off >= m->match_size))
1598		return -EINVAL;
1599
1600	if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1601	    put_user(match->revision, &cm->u.revision) ||
1602	    put_user(msize, &cm->match_size))
1603		return -EFAULT;
1604
1605	if (match->compat_to_user) {
1606		if (match->compat_to_user(cm->data, m->data))
1607			return -EFAULT;
1608	} else {
1609		if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1610				    COMPAT_XT_ALIGN(msize)))
1611			return -EFAULT;
1612	}
1613
1614	*size -= ebt_compat_entry_padsize() + off;
1615	*dstptr = cm->data;
1616	*dstptr += msize;
1617	return 0;
1618}
1619
1620static int compat_target_to_user(struct ebt_entry_target *t,
1621				 void __user **dstptr,
1622				 unsigned int *size)
1623{
1624	const struct xt_target *target = t->u.target;
1625	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1626	int off = xt_compat_target_offset(target);
1627	compat_uint_t tsize = t->target_size - off;
1628
1629	if (WARN_ON(off >= t->target_size))
1630		return -EINVAL;
1631
1632	if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1633	    put_user(target->revision, &cm->u.revision) ||
1634	    put_user(tsize, &cm->match_size))
1635		return -EFAULT;
1636
1637	if (target->compat_to_user) {
1638		if (target->compat_to_user(cm->data, t->data))
1639			return -EFAULT;
1640	} else {
1641		if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1642				    COMPAT_XT_ALIGN(tsize)))
1643			return -EFAULT;
1644	}
1645
1646	*size -= ebt_compat_entry_padsize() + off;
1647	*dstptr = cm->data;
1648	*dstptr += tsize;
1649	return 0;
1650}
1651
1652static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1653				  void __user **dstptr,
1654				  unsigned int *size)
1655{
1656	return compat_target_to_user((struct ebt_entry_target *)w,
1657							dstptr, size);
1658}
1659
1660static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1661				unsigned int *size)
1662{
1663	struct ebt_entry_target *t;
1664	struct ebt_entry __user *ce;
1665	u32 watchers_offset, target_offset, next_offset;
1666	compat_uint_t origsize;
1667	int ret;
1668
1669	if (e->bitmask == 0) {
1670		if (*size < sizeof(struct ebt_entries))
1671			return -EINVAL;
1672		if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1673			return -EFAULT;
1674
1675		*dstptr += sizeof(struct ebt_entries);
1676		*size -= sizeof(struct ebt_entries);
1677		return 0;
1678	}
1679
1680	if (*size < sizeof(*ce))
1681		return -EINVAL;
1682
1683	ce = *dstptr;
1684	if (copy_to_user(ce, e, sizeof(*ce)))
1685		return -EFAULT;
1686
1687	origsize = *size;
1688	*dstptr += sizeof(*ce);
1689
1690	ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1691	if (ret)
1692		return ret;
1693	watchers_offset = e->watchers_offset - (origsize - *size);
1694
1695	ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1696	if (ret)
1697		return ret;
1698	target_offset = e->target_offset - (origsize - *size);
1699
1700	t = ebt_get_target(e);
1701
1702	ret = compat_target_to_user(t, dstptr, size);
1703	if (ret)
1704		return ret;
1705	next_offset = e->next_offset - (origsize - *size);
1706
1707	if (put_user(watchers_offset, &ce->watchers_offset) ||
1708	    put_user(target_offset, &ce->target_offset) ||
1709	    put_user(next_offset, &ce->next_offset))
1710		return -EFAULT;
1711
1712	*size -= sizeof(*ce);
1713	return 0;
1714}
1715
1716static int compat_calc_match(struct ebt_entry_match *m, int *off)
1717{
1718	*off += ebt_compat_match_offset(m->u.match, m->match_size);
1719	*off += ebt_compat_entry_padsize();
1720	return 0;
1721}
1722
1723static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1724{
1725	*off += xt_compat_target_offset(w->u.watcher);
1726	*off += ebt_compat_entry_padsize();
1727	return 0;
1728}
1729
1730static int compat_calc_entry(const struct ebt_entry *e,
1731			     const struct ebt_table_info *info,
1732			     const void *base,
1733			     struct compat_ebt_replace *newinfo)
1734{
1735	const struct ebt_entry_target *t;
1736	unsigned int entry_offset;
1737	int off, ret, i;
1738
1739	if (e->bitmask == 0)
1740		return 0;
1741
1742	off = 0;
1743	entry_offset = (void *)e - base;
1744
1745	EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1746	EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1747
1748	t = ebt_get_target_c(e);
1749
1750	off += xt_compat_target_offset(t->u.target);
1751	off += ebt_compat_entry_padsize();
1752
1753	newinfo->entries_size -= off;
1754
1755	ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1756	if (ret)
1757		return ret;
1758
1759	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1760		const void *hookptr = info->hook_entry[i];
1761		if (info->hook_entry[i] &&
1762		    (e < (struct ebt_entry *)(base - hookptr))) {
1763			newinfo->hook_entry[i] -= off;
1764			pr_debug("0x%08X -> 0x%08X\n",
1765					newinfo->hook_entry[i] + off,
1766					newinfo->hook_entry[i]);
1767		}
1768	}
1769
1770	return 0;
1771}
1772
1773static int ebt_compat_init_offsets(unsigned int number)
1774{
1775	if (number > INT_MAX)
1776		return -EINVAL;
1777
1778	/* also count the base chain policies */
1779	number += NF_BR_NUMHOOKS;
1780
1781	return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1782}
1783
1784static int compat_table_info(const struct ebt_table_info *info,
1785			     struct compat_ebt_replace *newinfo)
1786{
1787	unsigned int size = info->entries_size;
1788	const void *entries = info->entries;
1789	int ret;
1790
1791	newinfo->entries_size = size;
1792	ret = ebt_compat_init_offsets(info->nentries);
1793	if (ret)
1794		return ret;
1795
1796	return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1797							entries, newinfo);
1798}
1799
1800static int compat_copy_everything_to_user(struct ebt_table *t,
1801					  void __user *user, int *len, int cmd)
1802{
1803	struct compat_ebt_replace repl, tmp;
1804	struct ebt_counter *oldcounters;
1805	struct ebt_table_info tinfo;
1806	int ret;
1807	void __user *pos;
1808
1809	memset(&tinfo, 0, sizeof(tinfo));
1810
1811	if (cmd == EBT_SO_GET_ENTRIES) {
1812		tinfo.entries_size = t->private->entries_size;
1813		tinfo.nentries = t->private->nentries;
1814		tinfo.entries = t->private->entries;
1815		oldcounters = t->private->counters;
1816	} else {
1817		tinfo.entries_size = t->table->entries_size;
1818		tinfo.nentries = t->table->nentries;
1819		tinfo.entries = t->table->entries;
1820		oldcounters = t->table->counters;
1821	}
1822
1823	if (copy_from_user(&tmp, user, sizeof(tmp)))
1824		return -EFAULT;
1825
1826	if (tmp.nentries != tinfo.nentries ||
1827	   (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1828		return -EINVAL;
1829
1830	memcpy(&repl, &tmp, sizeof(repl));
1831	if (cmd == EBT_SO_GET_ENTRIES)
1832		ret = compat_table_info(t->private, &repl);
1833	else
1834		ret = compat_table_info(&tinfo, &repl);
1835	if (ret)
1836		return ret;
1837
1838	if (*len != sizeof(tmp) + repl.entries_size +
1839	   (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1840		pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1841				*len, tinfo.entries_size, repl.entries_size);
1842		return -EINVAL;
1843	}
1844
1845	/* userspace might not need the counters */
1846	ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1847					tmp.num_counters, tinfo.nentries);
1848	if (ret)
1849		return ret;
1850
1851	pos = compat_ptr(tmp.entries);
1852	return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1853			compat_copy_entry_to_user, &pos, &tmp.entries_size);
1854}
1855
1856struct ebt_entries_buf_state {
1857	char *buf_kern_start;	/* kernel buffer to copy (translated) data to */
1858	u32 buf_kern_len;	/* total size of kernel buffer */
1859	u32 buf_kern_offset;	/* amount of data copied so far */
1860	u32 buf_user_offset;	/* read position in userspace buffer */
1861};
1862
1863static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1864{
1865	state->buf_kern_offset += sz;
1866	return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1867}
1868
1869static int ebt_buf_add(struct ebt_entries_buf_state *state,
1870		       const void *data, unsigned int sz)
1871{
1872	if (state->buf_kern_start == NULL)
1873		goto count_only;
1874
1875	if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1876		return -EINVAL;
1877
1878	memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1879
1880 count_only:
1881	state->buf_user_offset += sz;
1882	return ebt_buf_count(state, sz);
1883}
1884
1885static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1886{
1887	char *b = state->buf_kern_start;
1888
1889	if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1890		return -EINVAL;
1891
1892	if (b != NULL && sz > 0)
1893		memset(b + state->buf_kern_offset, 0, sz);
1894	/* do not adjust ->buf_user_offset here, we added kernel-side padding */
1895	return ebt_buf_count(state, sz);
1896}
1897
1898enum compat_mwt {
1899	EBT_COMPAT_MATCH,
1900	EBT_COMPAT_WATCHER,
1901	EBT_COMPAT_TARGET,
1902};
1903
1904static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1905				enum compat_mwt compat_mwt,
1906				struct ebt_entries_buf_state *state,
1907				const unsigned char *base)
1908{
1909	char name[EBT_EXTENSION_MAXNAMELEN];
1910	struct xt_match *match;
1911	struct xt_target *wt;
1912	void *dst = NULL;
1913	int off, pad = 0;
1914	unsigned int size_kern, match_size = mwt->match_size;
1915
1916	if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1917		return -EINVAL;
1918
1919	if (state->buf_kern_start)
1920		dst = state->buf_kern_start + state->buf_kern_offset;
1921
1922	switch (compat_mwt) {
1923	case EBT_COMPAT_MATCH:
1924		match = xt_request_find_match(NFPROTO_BRIDGE, name,
1925					      mwt->u.revision);
1926		if (IS_ERR(m

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