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	audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1050			AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1051	return ret;
1052
1053free_unlock:
1054	mutex_unlock(&ebt_mutex);
1055free_iterate:
1056	EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1057			  ebt_cleanup_entry, net, NULL);
1058free_counterstmp:
1059	vfree(counterstmp);
1060	/* can be initialized in translate_table() */
1061	ebt_free_table_info(newinfo);
1062	return ret;
1063}
1064
1065/* replace the table */
1066static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1067{
1068	int ret, countersize;
1069	struct ebt_table_info *newinfo;
1070	struct ebt_replace tmp;
1071
 
 
1072	if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1073		return -EFAULT;
1074
1075	if (len != sizeof(tmp) + tmp.entries_size)
1076		return -EINVAL;
1077
1078	if (tmp.entries_size == 0)
1079		return -EINVAL;
1080
1081	/* overflow check */
1082	if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1083			NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1084		return -ENOMEM;
1085	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1086		return -ENOMEM;
1087
1088	tmp.name[sizeof(tmp.name) - 1] = 0;
1089
1090	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1091	newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1092	if (!newinfo)
1093		return -ENOMEM;
1094
1095	if (countersize)
1096		memset(newinfo->counters, 0, countersize);
1097
1098	newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1099	if (!newinfo->entries) {
1100		ret = -ENOMEM;
1101		goto free_newinfo;
1102	}
1103	if (copy_from_user(
1104	   newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1105		ret = -EFAULT;
1106		goto free_entries;
1107	}
1108
1109	ret = do_replace_finish(net, &tmp, newinfo);
1110	if (ret == 0)
1111		return ret;
1112free_entries:
1113	vfree(newinfo->entries);
1114free_newinfo:
1115	vfree(newinfo);
1116	return ret;
1117}
1118
1119static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1120{
1121	mutex_lock(&ebt_mutex);
1122	list_del(&table->list);
1123	mutex_unlock(&ebt_mutex);
1124	audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1125			AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1126	EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1127			  ebt_cleanup_entry, net, NULL);
1128	if (table->private->nentries)
1129		module_put(table->me);
1130	vfree(table->private->entries);
1131	ebt_free_table_info(table->private);
1132	vfree(table->private);
 
1133	kfree(table);
1134}
1135
1136int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1137		       const struct nf_hook_ops *ops, struct ebt_table **res)
1138{
 
1139	struct ebt_table_info *newinfo;
1140	struct ebt_table *t, *table;
 
 
1141	struct ebt_replace_kernel *repl;
1142	int ret, i, countersize;
1143	void *p;
1144
1145	if (input_table == NULL || (repl = input_table->table) == NULL ||
1146	    repl->entries == NULL || repl->entries_size == 0 ||
1147	    repl->counters != NULL || input_table->private != NULL)
1148		return -EINVAL;
1149
1150	/* Don't add one table to multiple lists. */
1151	table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1152	if (!table) {
1153		ret = -ENOMEM;
1154		goto out;
1155	}
1156
1157	countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1158	newinfo = vmalloc(sizeof(*newinfo) + countersize);
1159	ret = -ENOMEM;
1160	if (!newinfo)
1161		goto free_table;
1162
1163	p = vmalloc(repl->entries_size);
1164	if (!p)
1165		goto free_newinfo;
1166
1167	memcpy(p, repl->entries, repl->entries_size);
1168	newinfo->entries = p;
1169
1170	newinfo->entries_size = repl->entries_size;
1171	newinfo->nentries = repl->nentries;
1172
1173	if (countersize)
1174		memset(newinfo->counters, 0, countersize);
1175
1176	/* fill in newinfo and parse the entries */
1177	newinfo->chainstack = NULL;
1178	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1179		if ((repl->valid_hooks & (1 << i)) == 0)
1180			newinfo->hook_entry[i] = NULL;
1181		else
1182			newinfo->hook_entry[i] = p +
1183				((char *)repl->hook_entry[i] - repl->entries);
1184	}
1185	ret = translate_table(net, repl->name, newinfo);
1186	if (ret != 0)
1187		goto free_chainstack;
1188
1189	if (table->check && table->check(newinfo, table->valid_hooks)) {
1190		ret = -EINVAL;
1191		goto free_chainstack;
1192	}
1193
1194	table->private = newinfo;
1195	rwlock_init(&table->lock);
1196	mutex_lock(&ebt_mutex);
1197	list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1198		if (strcmp(t->name, table->name) == 0) {
1199			ret = -EEXIST;
1200			goto free_unlock;
1201		}
1202	}
1203
1204	/* Hold a reference count if the chains aren't empty */
1205	if (newinfo->nentries && !try_module_get(table->me)) {
1206		ret = -ENOENT;
1207		goto free_unlock;
1208	}
1209	list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1210	mutex_unlock(&ebt_mutex);
1211
1212	WRITE_ONCE(*res, table);
1213	ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1214	if (ret) {
1215		__ebt_unregister_table(net, table);
1216		*res = NULL;
1217	}
1218
1219	audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1220			AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1221	return ret;
1222free_unlock:
1223	mutex_unlock(&ebt_mutex);
1224free_chainstack:
1225	ebt_free_table_info(newinfo);
1226	vfree(newinfo->entries);
1227free_newinfo:
1228	vfree(newinfo);
1229free_table:
1230	kfree(table);
1231out:
1232	return ret;
1233}
1234
1235void ebt_unregister_table(struct net *net, struct ebt_table *table,
1236			  const struct nf_hook_ops *ops)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1237{
1238	nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1239	__ebt_unregister_table(net, table);
 
 
 
 
 
 
 
 
 
 
 
1240}
1241
1242/* userspace just supplied us with counters */
1243static int do_update_counters(struct net *net, const char *name,
1244			      struct ebt_counter __user *counters,
1245			      unsigned int num_counters, unsigned int len)
1246{
1247	int i, ret;
1248	struct ebt_counter *tmp;
1249	struct ebt_table *t;
1250
1251	if (num_counters == 0)
1252		return -EINVAL;
1253
1254	tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1255	if (!tmp)
1256		return -ENOMEM;
1257
1258	t = find_table_lock(net, name, &ret, &ebt_mutex);
1259	if (!t)
1260		goto free_tmp;
1261
1262	if (num_counters != t->private->nentries) {
1263		ret = -EINVAL;
1264		goto unlock_mutex;
1265	}
1266
1267	if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
 
1268		ret = -EFAULT;
1269		goto unlock_mutex;
1270	}
1271
1272	/* we want an atomic add of the counters */
1273	write_lock_bh(&t->lock);
1274
1275	/* we add to the counters of the first cpu */
1276	for (i = 0; i < num_counters; i++)
1277		ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1278
1279	write_unlock_bh(&t->lock);
1280	ret = 0;
1281unlock_mutex:
1282	mutex_unlock(&ebt_mutex);
1283free_tmp:
1284	vfree(tmp);
1285	return ret;
1286}
1287
1288static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1289{
1290	struct ebt_replace hlp;
1291
 
 
1292	if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1293		return -EFAULT;
1294
1295	if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1296		return -EINVAL;
1297
1298	return do_update_counters(net, hlp.name, hlp.counters,
1299				  hlp.num_counters, len);
1300}
1301
1302static inline int ebt_obj_to_user(char __user *um, const char *_name,
1303				  const char *data, int entrysize,
1304				  int usersize, int datasize, u8 revision)
1305{
1306	char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1307
1308	/* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1309	 * long. Copy 29 bytes and fill remaining bytes with zeroes.
1310	 */
1311	strlcpy(name, _name, sizeof(name));
1312	if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1313	    put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1314	    put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1315	    xt_data_to_user(um + entrysize, data, usersize, datasize,
1316			    XT_ALIGN(datasize)))
1317		return -EFAULT;
1318
1319	return 0;
1320}
1321
1322static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1323				    const char *base, char __user *ubase)
1324{
1325	return ebt_obj_to_user(ubase + ((char *)m - base),
1326			       m->u.match->name, m->data, sizeof(*m),
1327			       m->u.match->usersize, m->match_size,
1328			       m->u.match->revision);
1329}
1330
1331static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1332				      const char *base, char __user *ubase)
1333{
1334	return ebt_obj_to_user(ubase + ((char *)w - base),
1335			       w->u.watcher->name, w->data, sizeof(*w),
1336			       w->u.watcher->usersize, w->watcher_size,
1337			       w->u.watcher->revision);
1338}
1339
1340static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1341				    char __user *ubase)
1342{
1343	int ret;
1344	char __user *hlp;
1345	const struct ebt_entry_target *t;
1346
1347	if (e->bitmask == 0) {
1348		/* special case !EBT_ENTRY_OR_ENTRIES */
1349		if (copy_to_user(ubase + ((char *)e - base), e,
1350				 sizeof(struct ebt_entries)))
1351			return -EFAULT;
1352		return 0;
1353	}
1354
1355	if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1356		return -EFAULT;
1357
1358	hlp = ubase + (((char *)e + e->target_offset) - base);
1359	t = ebt_get_target_c(e);
1360
1361	ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1362	if (ret != 0)
1363		return ret;
1364	ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1365	if (ret != 0)
1366		return ret;
1367	ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1368			      t->u.target->usersize, t->target_size,
1369			      t->u.target->revision);
1370	if (ret != 0)
1371		return ret;
1372
1373	return 0;
1374}
1375
1376static int copy_counters_to_user(struct ebt_table *t,
1377				 const struct ebt_counter *oldcounters,
1378				 void __user *user, unsigned int num_counters,
1379				 unsigned int nentries)
1380{
1381	struct ebt_counter *counterstmp;
1382	int ret = 0;
1383
1384	/* userspace might not need the counters */
1385	if (num_counters == 0)
1386		return 0;
1387
1388	if (num_counters != nentries)
1389		return -EINVAL;
1390
1391	counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1392	if (!counterstmp)
1393		return -ENOMEM;
1394
1395	write_lock_bh(&t->lock);
1396	get_counters(oldcounters, counterstmp, nentries);
1397	write_unlock_bh(&t->lock);
1398
1399	if (copy_to_user(user, counterstmp,
1400	   nentries * sizeof(struct ebt_counter)))
1401		ret = -EFAULT;
1402	vfree(counterstmp);
1403	return ret;
1404}
1405
1406/* called with ebt_mutex locked */
1407static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1408				   const int *len, int cmd)
1409{
1410	struct ebt_replace tmp;
1411	const struct ebt_counter *oldcounters;
1412	unsigned int entries_size, nentries;
1413	int ret;
1414	char *entries;
1415
1416	if (cmd == EBT_SO_GET_ENTRIES) {
1417		entries_size = t->private->entries_size;
1418		nentries = t->private->nentries;
1419		entries = t->private->entries;
1420		oldcounters = t->private->counters;
1421	} else {
1422		entries_size = t->table->entries_size;
1423		nentries = t->table->nentries;
1424		entries = t->table->entries;
1425		oldcounters = t->table->counters;
1426	}
1427
1428	if (copy_from_user(&tmp, user, sizeof(tmp)))
1429		return -EFAULT;
1430
1431	if (*len != sizeof(struct ebt_replace) + entries_size +
1432	   (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1433		return -EINVAL;
1434
1435	if (tmp.nentries != nentries)
1436		return -EINVAL;
1437
1438	if (tmp.entries_size != entries_size)
1439		return -EINVAL;
1440
1441	ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1442					tmp.num_counters, nentries);
1443	if (ret)
1444		return ret;
1445
1446	/* set the match/watcher/target names right */
1447	return EBT_ENTRY_ITERATE(entries, entries_size,
1448	   ebt_entry_to_user, entries, tmp.entries);
1449}
1450
1451#ifdef CONFIG_COMPAT
1452/* 32 bit-userspace compatibility definitions. */
1453struct compat_ebt_replace {
1454	char name[EBT_TABLE_MAXNAMELEN];
1455	compat_uint_t valid_hooks;
1456	compat_uint_t nentries;
1457	compat_uint_t entries_size;
1458	/* start of the chains */
1459	compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1460	/* nr of counters userspace expects back */
1461	compat_uint_t num_counters;
1462	/* where the kernel will put the old counters. */
1463	compat_uptr_t counters;
1464	compat_uptr_t entries;
1465};
1466
1467/* struct ebt_entry_match, _target and _watcher have same layout */
1468struct compat_ebt_entry_mwt {
1469	union {
1470		struct {
1471			char name[EBT_EXTENSION_MAXNAMELEN];
1472			u8 revision;
1473		};
1474		compat_uptr_t ptr;
1475	} u;
1476	compat_uint_t match_size;
1477	compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1478};
1479
1480/* account for possible padding between match_size and ->data */
1481static int ebt_compat_entry_padsize(void)
1482{
1483	BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1484			sizeof(struct compat_ebt_entry_mwt));
1485	return (int) sizeof(struct ebt_entry_match) -
1486			sizeof(struct compat_ebt_entry_mwt);
1487}
1488
1489static int ebt_compat_match_offset(const struct xt_match *match,
1490				   unsigned int userlen)
1491{
1492	/* ebt_among needs special handling. The kernel .matchsize is
1493	 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1494	 * value is expected.
1495	 * Example: userspace sends 4500, ebt_among.c wants 4504.
1496	 */
1497	if (unlikely(match->matchsize == -1))
1498		return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1499	return xt_compat_match_offset(match);
1500}
1501
1502static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1503				unsigned int *size)
1504{
1505	const struct xt_match *match = m->u.match;
1506	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1507	int off = ebt_compat_match_offset(match, m->match_size);
1508	compat_uint_t msize = m->match_size - off;
1509
1510	if (WARN_ON(off >= m->match_size))
1511		return -EINVAL;
1512
1513	if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1514	    put_user(match->revision, &cm->u.revision) ||
1515	    put_user(msize, &cm->match_size))
1516		return -EFAULT;
1517
1518	if (match->compat_to_user) {
1519		if (match->compat_to_user(cm->data, m->data))
1520			return -EFAULT;
1521	} else {
1522		if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1523				    COMPAT_XT_ALIGN(msize)))
1524			return -EFAULT;
1525	}
1526
1527	*size -= ebt_compat_entry_padsize() + off;
1528	*dstptr = cm->data;
1529	*dstptr += msize;
1530	return 0;
1531}
1532
1533static int compat_target_to_user(struct ebt_entry_target *t,
1534				 void __user **dstptr,
1535				 unsigned int *size)
1536{
1537	const struct xt_target *target = t->u.target;
1538	struct compat_ebt_entry_mwt __user *cm = *dstptr;
1539	int off = xt_compat_target_offset(target);
1540	compat_uint_t tsize = t->target_size - off;
1541
1542	if (WARN_ON(off >= t->target_size))
1543		return -EINVAL;
1544
1545	if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1546	    put_user(target->revision, &cm->u.revision) ||
1547	    put_user(tsize, &cm->match_size))
1548		return -EFAULT;
1549
1550	if (target->compat_to_user) {
1551		if (target->compat_to_user(cm->data, t->data))
1552			return -EFAULT;
1553	} else {
1554		if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1555				    COMPAT_XT_ALIGN(tsize)))
1556			return -EFAULT;
1557	}
1558
1559	*size -= ebt_compat_entry_padsize() + off;
1560	*dstptr = cm->data;
1561	*dstptr += tsize;
1562	return 0;
1563}
1564
1565static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1566				  void __user **dstptr,
1567				  unsigned int *size)
1568{
1569	return compat_target_to_user((struct ebt_entry_target *)w,
1570							dstptr, size);
1571}
1572
1573static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1574				unsigned int *size)
1575{
1576	struct ebt_entry_target *t;
1577	struct ebt_entry __user *ce;
1578	u32 watchers_offset, target_offset, next_offset;
1579	compat_uint_t origsize;
1580	int ret;
1581
1582	if (e->bitmask == 0) {
1583		if (*size < sizeof(struct ebt_entries))
1584			return -EINVAL;
1585		if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1586			return -EFAULT;
1587
1588		*dstptr += sizeof(struct ebt_entries);
1589		*size -= sizeof(struct ebt_entries);
1590		return 0;
1591	}
1592
1593	if (*size < sizeof(*ce))
1594		return -EINVAL;
1595
1596	ce = *dstptr;
1597	if (copy_to_user(ce, e, sizeof(*ce)))
1598		return -EFAULT;
1599
1600	origsize = *size;
1601	*dstptr += sizeof(*ce);
1602
1603	ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1604	if (ret)
1605		return ret;
1606	watchers_offset = e->watchers_offset - (origsize - *size);
1607
1608	ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1609	if (ret)
1610		return ret;
1611	target_offset = e->target_offset - (origsize - *size);
1612
1613	t = ebt_get_target(e);
1614
1615	ret = compat_target_to_user(t, dstptr, size);
1616	if (ret)
1617		return ret;
1618	next_offset = e->next_offset - (origsize - *size);
1619
1620	if (put_user(watchers_offset, &ce->watchers_offset) ||
1621	    put_user(target_offset, &ce->target_offset) ||
1622	    put_user(next_offset, &ce->next_offset))
1623		return -EFAULT;
1624
1625	*size -= sizeof(*ce);
1626	return 0;
1627}
1628
1629static int compat_calc_match(struct ebt_entry_match *m, int *off)
1630{
1631	*off += ebt_compat_match_offset(m->u.match, m->match_size);
1632	*off += ebt_compat_entry_padsize();
1633	return 0;
1634}
1635
1636static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1637{
1638	*off += xt_compat_target_offset(w->u.watcher);
1639	*off += ebt_compat_entry_padsize();
1640	return 0;
1641}
1642
1643static int compat_calc_entry(const struct ebt_entry *e,
1644			     const struct ebt_table_info *info,
1645			     const void *base,
1646			     struct compat_ebt_replace *newinfo)
1647{
1648	const struct ebt_entry_target *t;
1649	unsigned int entry_offset;
1650	int off, ret, i;
1651
1652	if (e->bitmask == 0)
1653		return 0;
1654
1655	off = 0;
1656	entry_offset = (void *)e - base;
1657
1658	EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1659	EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1660
1661	t = ebt_get_target_c(e);
1662
1663	off += xt_compat_target_offset(t->u.target);
1664	off += ebt_compat_entry_padsize();
1665
1666	newinfo->entries_size -= off;
1667
1668	ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1669	if (ret)
1670		return ret;
1671
1672	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1673		const void *hookptr = info->hook_entry[i];
1674		if (info->hook_entry[i] &&
1675		    (e < (struct ebt_entry *)(base - hookptr))) {
1676			newinfo->hook_entry[i] -= off;
1677			pr_debug("0x%08X -> 0x%08X\n",
1678					newinfo->hook_entry[i] + off,
1679					newinfo->hook_entry[i]);
1680		}
1681	}
1682
1683	return 0;
1684}
1685
1686static int ebt_compat_init_offsets(unsigned int number)
1687{
1688	if (number > INT_MAX)
1689		return -EINVAL;
1690
1691	/* also count the base chain policies */
1692	number += NF_BR_NUMHOOKS;
1693
1694	return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1695}
1696
1697static int compat_table_info(const struct ebt_table_info *info,
1698			     struct compat_ebt_replace *newinfo)
1699{
1700	unsigned int size = info->entries_size;
1701	const void *entries = info->entries;
1702	int ret;
1703
1704	newinfo->entries_size = size;
1705	ret = ebt_compat_init_offsets(info->nentries);
1706	if (ret)
1707		return ret;
1708
1709	return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1710							entries, newinfo);
1711}
1712
1713static int compat_copy_everything_to_user(struct ebt_table *t,
1714					  void __user *user, int *len, int cmd)
1715{
1716	struct compat_ebt_replace repl, tmp;
1717	struct ebt_counter *oldcounters;
1718	struct ebt_table_info tinfo;
1719	int ret;
1720	void __user *pos;
1721
1722	memset(&tinfo, 0, sizeof(tinfo));
1723
1724	if (cmd == EBT_SO_GET_ENTRIES) {
1725		tinfo.entries_size = t->private->entries_size;
1726		tinfo.nentries = t->private->nentries;
1727		tinfo.entries = t->private->entries;
1728		oldcounters = t->private->counters;
1729	} else {
1730		tinfo.entries_size = t->table->entries_size;
1731		tinfo.nentries = t->table->nentries;
1732		tinfo.entries = t->table->entries;
1733		oldcounters = t->table->counters;
1734	}
1735
1736	if (copy_from_user(&tmp, user, sizeof(tmp)))
1737		return -EFAULT;
1738
1739	if (tmp.nentries != tinfo.nentries ||
1740	   (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1741		return -EINVAL;
1742
1743	memcpy(&repl, &tmp, sizeof(repl));
1744	if (cmd == EBT_SO_GET_ENTRIES)
1745		ret = compat_table_info(t->private, &repl);
1746	else
1747		ret = compat_table_info(&tinfo, &repl);
1748	if (ret)
1749		return ret;
1750
1751	if (*len != sizeof(tmp) + repl.entries_size +
1752	   (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1753		pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1754				*len, tinfo.entries_size, repl.entries_size);
1755		return -EINVAL;
1756	}
1757
1758	/* userspace might not need the counters */
1759	ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1760					tmp.num_counters, tinfo.nentries);
1761	if (ret)
1762		return ret;
1763
1764	pos = compat_ptr(tmp.entries);
1765	return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1766			compat_copy_entry_to_user, &pos, &tmp.entries_size);
1767}
1768
1769struct ebt_entries_buf_state {
1770	char *buf_kern_start;	/* kernel buffer to copy (translated) data to */
1771	u32 buf_kern_len;	/* total size of kernel buffer */
1772	u32 buf_kern_offset;	/* amount of data copied so far */
1773	u32 buf_user_offset;	/* read position in userspace buffer */
1774};
1775
1776static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1777{
1778	state->buf_kern_offset += sz;
1779	return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1780}
1781
1782static int ebt_buf_add(struct ebt_entries_buf_state *state,
1783		       const void *data, unsigned int sz)
1784{
1785	if (state->buf_kern_start == NULL)
1786		goto count_only;
1787
1788	if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1789		return -EINVAL;
1790
1791	memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1792
1793 count_only:
1794	state->buf_user_offset += sz;
1795	return ebt_buf_count(state, sz);
1796}
1797
1798static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1799{
1800	char *b = state->buf_kern_start;
1801
1802	if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1803		return -EINVAL;
1804
1805	if (b != NULL && sz > 0)
1806		memset(b + state->buf_kern_offset, 0, sz);
1807	/* do not adjust ->buf_user_offset here, we added kernel-side padding */
1808	return ebt_buf_count(state, sz);
1809}
1810
1811enum compat_mwt {
1812	EBT_COMPAT_MATCH,
1813	EBT_COMPAT_WATCHER,
1814	EBT_COMPAT_TARGET,
1815};
1816
1817static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1818				enum compat_mwt compat_mwt,
1819				struct ebt_entries_buf_state *state,
1820				const unsigned char *base)
1821{
1822	char name[EBT_EXTENSION_MAXNAMELEN];
1823	struct xt_match *match;
1824	struct xt_target *wt;
1825	void *dst = NULL;
1826	int off, pad = 0;
1827	unsigned int size_kern, match_size = mwt->match_size;
1828
1829	if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1830		return -EINVAL;
1831
1832	if (state->buf_kern_start)
1833		dst = state->buf_kern_start + state->buf_kern_offset;
1834
1835	switch (compat_mwt) {
1836	case EBT_COMPAT_MATCH:
1837		match = xt_request_find_match(NFPROTO_BRIDGE, name,
1838					      mwt->u.revision);
1839		if (IS_ERR(match))
1840			return PTR_ERR(match);
1841
1842		off = ebt_compat_match_offset(match, match_size);
1843		if (dst) {
1844			if (match->compat_from_user)
1845				match->compat_from_user(dst, mwt->data);
1846			else
1847				memcpy(dst, mwt->data, match_size);
1848		}
1849
1850		size_kern = match->matchsize;
1851		if (unlikely(size_kern == -1))
1852			size_kern = match_size;
1853		module_put(match->me);
1854		break;
1855	case EBT_COMPAT_WATCHER:
1856	case EBT_COMPAT_TARGET:
1857		wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1858					    mwt->u.revision);
1859		if (IS_ERR(wt))
1860			return PTR_ERR(wt);
1861		off = xt_compat_target_offset(wt);
1862
1863		if (dst) {
1864			if (wt->compat_from_user)
1865				wt->compat_from_user(dst, mwt->data);
1866			else
1867				memcpy(dst, mwt->data, match_size);
1868		}
1869
1870		size_kern = wt->targetsize;
1871		module_put(wt->me);
1872		break;
1873
1874	default:
1875		return -EINVAL;
1876	}
1877
1878	state->buf_kern_offset += match_size + off;
1879	state->buf_user_offset += match_size;
1880	pad = XT_ALIGN(size_kern) - size_kern;
1881
1882	if (pad > 0 && dst) {
1883		if (WARN_ON(state->buf_kern_len <= pad))
1884			return -EINVAL;
1885		if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
1886			return -EINVAL;
1887		memset(dst + size_kern, 0, pad);
1888	}
1889	return off + match_size;
1890}
1891
1892/* return size of all matches, watchers or target, including necessary
1893 * alignment and padding.
1894 */
1895static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
1896			unsigned int size_left, enum compat_mwt type,
1897			struct ebt_entries_buf_state *state, const void *base)
1898{
1899	const char *buf = (const char *)match32;
1900	int growth = 0;
1901
1902	if (size_left == 0)
1903		return 0;
1904
1905	do {
1906		struct ebt_entry_match *match_kern;
1907		int ret;
1908
1909		if (size_left < sizeof(*match32))
1910			return -EINVAL;
1911
1912		match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1913		if (match_kern) {
1914			char *tmp;
1915			tmp = state->buf_kern_start + state->buf_kern_offset;
1916			match_kern = (struct ebt_entry_match *) tmp;
1917		}
1918		ret = ebt_buf_add(state, buf, sizeof(*match32));
1919		if (ret < 0)
1920			return ret;
1921		size_left -= sizeof(*match32);
1922
1923		/* add padding before match->data (if any) */
1924		ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
1925		if (ret < 0)
1926			return ret;
1927
1928		if (match32->match_size > size_left)
1929			return -EINVAL;
1930
1931		size_left -= match32->match_size;
1932
1933		ret = compat_mtw_from_user(match32, type, state, base);
1934		if (ret < 0)
1935			return ret;
1936
1937		if (WARN_ON(ret < match32->match_size))
1938			return -EINVAL;
1939		growth += ret - match32->match_size;
1940		growth += ebt_compat_entry_padsize();
1941
1942		buf += sizeof(*match32);
1943		buf += match32->match_size;
1944
1945		if (match_kern)
1946			match_kern->match_size = ret;
1947
1948		match32 = (struct compat_ebt_entry_mwt *) buf;
1949	} while (size_left);
1950
1951	return growth;
1952}
1953
1954/* called for all ebt_entry structures. */
1955static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
1956			  unsigned int *total,
1957			  struct ebt_entries_buf_state *state)
1958{
1959	unsigned int i, j, startoff, next_expected_off, new_offset = 0;
1960	/* stores match/watchers/targets & offset of next struct ebt_entry: */
1961	unsigned int offsets[4];
1962	unsigned int *offsets_update = NULL;
1963	int ret;
1964	char *buf_start;
1965
1966	if (*total < sizeof(struct ebt_entries))
1967		return -EINVAL;
1968
1969	if (!entry->bitmask) {
1970		*total -= sizeof(struct ebt_entries);
1971		return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
1972	}
1973	if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
1974		return -EINVAL;
1975
1976	startoff = state->buf_user_offset;
1977	/* pull in most part of ebt_entry, it does not need to be changed. */
1978	ret = ebt_buf_add(state, entry,
1979			offsetof(struct ebt_entry, watchers_offset));
1980	if (ret < 0)
1981		return ret;
1982
1983	offsets[0] = sizeof(struct ebt_entry); /* matches come first */
1984	memcpy(&offsets[1], &entry->watchers_offset,
1985			sizeof(offsets) - sizeof(offsets[0]));
1986
1987	if (state->buf_kern_start) {
1988		buf_start = state->buf_kern_start + state->buf_kern_offset;
1989		offsets_update = (unsigned int *) buf_start;
1990	}
1991	ret = ebt_buf_add(state, &offsets[1],
1992			sizeof(offsets) - sizeof(offsets[0]));
1993	if (ret < 0)
1994		return ret;
1995	buf_start = (char *) entry;
1996	/* 0: matches offset, always follows ebt_entry.
1997	 * 1: watchers offset, from ebt_entry structure
1998	 * 2: target offset, from ebt_entry structure
1999	 * 3: next ebt_entry offset, from ebt_entry structure
2000	 *
2001	 * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2002	 */
2003	for (i = 0; i < 4 ; ++i) {
2004		if (offsets[i] > *total)
2005			return -EINVAL;
2006
2007		if (i < 3 && offsets[i] == *total)
2008			return -EINVAL;
2009
2010		if (i == 0)
2011			continue;
2012		if (offsets[i-1] > offsets[i])
2013			return -EINVAL;
2014	}
2015
2016	for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2017		struct compat_ebt_entry_mwt *match32;
2018		unsigned int size;
2019		char *buf = buf_start + offsets[i];
2020
2021		if (offsets[i] > offsets[j])
2022			return -EINVAL;
2023
2024		match32 = (struct compat_ebt_entry_mwt *) buf;
2025		size = offsets[j] - offsets[i];
2026		ret = ebt_size_mwt(match32, size, i, state, base);
2027		if (ret < 0)
2028			return ret;
2029		new_offset += ret;
2030		if (offsets_update && new_offset) {
2031			pr_debug("change offset %d to %d\n",
2032				offsets_update[i], offsets[j] + new_offset);
2033			offsets_update[i] = offsets[j] + new_offset;
2034		}
2035	}
2036
2037	if (state->buf_kern_start == NULL) {
2038		unsigned int offset = buf_start - (char *) base;
2039
2040		ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2041		if (ret < 0)
2042			return ret;
2043	}
2044
2045	next_expected_off = state->buf_user_offset - startoff;
2046	if (next_expected_off != entry->next_offset)
2047		return -EINVAL;
2048
2049	if (*total < entry->next_offset)
2050		return -EINVAL;
2051	*total -= entry->next_offset;
2052	return 0;
2053}
2054
2055/* repl->entries_size is the size of the ebt_entry blob in userspace.
2056 * It might need more memory when copied to a 64 bit kernel in case
2057 * userspace is 32-bit. So, first task: find out how much memory is needed.
2058 *
2059 * Called before validation is performed.
2060 */
2061static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2062				struct ebt_entries_buf_state *state)
2063{
2064	unsigned int size_remaining = size_user;
2065	int ret;
2066
2067	ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2068					&size_remaining, state);
2069	if (ret < 0)
2070		return ret;
2071
2072	if (size_remaining)
2073		return -EINVAL;
2074
2075	return state->buf_kern_offset;
2076}
2077
2078
2079static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2080					     sockptr_t arg, unsigned int len)
2081{
2082	struct compat_ebt_replace tmp;
2083	int i;
2084
2085	if (len < sizeof(tmp))
2086		return -EINVAL;
2087
2088	if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2089		return -EFAULT;
2090
2091	if (len != sizeof(tmp) + tmp.entries_size)
2092		return -EINVAL;
2093
2094	if (tmp.entries_size == 0)
2095		return -EINVAL;
2096
2097	if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2098			NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2099		return -ENOMEM;
2100	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2101		return -ENOMEM;
2102
2103	memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2104
2105	/* starting with hook_entry, 32 vs. 64 bit structures are different */
2106	for (i = 0; i < NF_BR_NUMHOOKS; i++)
2107		repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2108
2109	repl->num_counters = tmp.num_counters;
2110	repl->counters = compat_ptr(tmp.counters);
2111	repl->entries = compat_ptr(tmp.entries);
2112	return 0;
2113}
2114
2115static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2116{
2117	int ret, i, countersize, size64;
2118	struct ebt_table_info *newinfo;
2119	struct ebt_replace tmp;
2120	struct ebt_entries_buf_state state;
2121	void *entries_tmp;
2122
2123	ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2124	if (ret) {
2125		/* try real handler in case userland supplied needed padding */
2126		if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2127			ret = 0;
2128		return ret;
2129	}
2130
2131	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2132	newinfo = vmalloc(sizeof(*newinfo) + countersize);
2133	if (!newinfo)
2134		return -ENOMEM;
2135
2136	if (countersize)
2137		memset(newinfo->counters, 0, countersize);
2138
2139	memset(&state, 0, sizeof(state));
2140
2141	newinfo->entries = vmalloc(tmp.entries_size);
2142	if (!newinfo->entries) {
2143		ret = -ENOMEM;
2144		goto free_newinfo;
2145	}
2146	if (copy_from_user(
2147	   newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2148		ret = -EFAULT;
2149		goto free_entries;
2150	}
2151
2152	entries_tmp = newinfo->entries;
2153
2154	xt_compat_lock(NFPROTO_BRIDGE);
2155
2156	ret = ebt_compat_init_offsets(tmp.nentries);
2157	if (ret < 0)
2158		goto out_unlock;
2159
2160	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2161	if (ret < 0)
2162		goto out_unlock;
2163
2164	pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2165		tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2166		xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2167
2168	size64 = ret;
2169	newinfo->entries = vmalloc(size64);
2170	if (!newinfo->entries) {
2171		vfree(entries_tmp);
2172		ret = -ENOMEM;
2173		goto out_unlock;
2174	}
2175
2176	memset(&state, 0, sizeof(state));
2177	state.buf_kern_start = newinfo->entries;
2178	state.buf_kern_len = size64;
2179
2180	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2181	if (WARN_ON(ret < 0)) {
2182		vfree(entries_tmp);
2183		goto out_unlock;
2184	}
2185
2186	vfree(entries_tmp);
2187	tmp.entries_size = size64;
2188
2189	for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2190		char __user *usrptr;
2191		if (tmp.hook_entry[i]) {
2192			unsigned int delta;
2193			usrptr = (char __user *) tmp.hook_entry[i];
2194			delta = usrptr - tmp.entries;
2195			usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2196			tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2197		}
2198	}
2199
2200	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2201	xt_compat_unlock(NFPROTO_BRIDGE);
2202
2203	ret = do_replace_finish(net, &tmp, newinfo);
2204	if (ret == 0)
2205		return ret;
2206free_entries:
2207	vfree(newinfo->entries);
2208free_newinfo:
2209	vfree(newinfo);
2210	return ret;
2211out_unlock:
2212	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2213	xt_compat_unlock(NFPROTO_BRIDGE);
2214	goto free_entries;
2215}
2216
2217static int compat_update_counters(struct net *net, sockptr_t arg,
2218				  unsigned int len)
2219{
2220	struct compat_ebt_replace hlp;
2221
 
 
2222	if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2223		return -EFAULT;
2224
2225	/* try real handler in case userland supplied needed padding */
2226	if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2227		return update_counters(net, arg, len);
2228
2229	return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2230				  hlp.num_counters, len);
2231}
2232
2233static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2234		void __user *user, int *len)
2235{
2236	int ret;
2237	struct compat_ebt_replace tmp;
2238	struct ebt_table *t;
2239	struct net *net = sock_net(sk);
2240
2241	if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2242	    *len != sizeof(struct compat_ebt_replace))
2243		return -EINVAL;
2244
2245	if (copy_from_user(&tmp, user, sizeof(tmp)))
2246		return -EFAULT;
2247
2248	tmp.name[sizeof(tmp.name) - 1] = '\0';
2249
2250	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2251	if (!t)
2252		return ret;
2253
2254	xt_compat_lock(NFPROTO_BRIDGE);
2255	switch (cmd) {
2256	case EBT_SO_GET_INFO:
2257		tmp.nentries = t->private->nentries;
2258		ret = compat_table_info(t->private, &tmp);
2259		if (ret)
2260			goto out;
2261		tmp.valid_hooks = t->valid_hooks;
2262
2263		if (copy_to_user(user, &tmp, *len) != 0) {
2264			ret = -EFAULT;
2265			break;
2266		}
2267		ret = 0;
2268		break;
2269	case EBT_SO_GET_INIT_INFO:
2270		tmp.nentries = t->table->nentries;
2271		tmp.entries_size = t->table->entries_size;
2272		tmp.valid_hooks = t->table->valid_hooks;
2273
2274		if (copy_to_user(user, &tmp, *len) != 0) {
2275			ret = -EFAULT;
2276			break;
2277		}
2278		ret = 0;
2279		break;
2280	case EBT_SO_GET_ENTRIES:
2281	case EBT_SO_GET_INIT_ENTRIES:
2282		/* try real handler first in case of userland-side padding.
2283		 * in case we are dealing with an 'ordinary' 32 bit binary
2284		 * without 64bit compatibility padding, this will fail right
2285		 * after copy_from_user when the *len argument is validated.
2286		 *
2287		 * the compat_ variant needs to do one pass over the kernel
2288		 * data set to adjust for size differences before it the check.
2289		 */
2290		if (copy_everything_to_user(t, user, len, cmd) == 0)
2291			ret = 0;
2292		else
2293			ret = compat_copy_everything_to_user(t, user, len, cmd);
2294		break;
2295	default:
2296		ret = -EINVAL;
2297	}
2298 out:
2299	xt_compat_flush_offsets(NFPROTO_BRIDGE);
2300	xt_compat_unlock(NFPROTO_BRIDGE);
2301	mutex_unlock(&ebt_mutex);
2302	return ret;
2303}
2304#endif
2305
2306static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2307{
2308	struct net *net = sock_net(sk);
2309	struct ebt_replace tmp;
2310	struct ebt_table *t;
2311	int ret;
2312
2313	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2314		return -EPERM;
2315
2316#ifdef CONFIG_COMPAT
2317	/* try real handler in case userland supplied needed padding */
2318	if (in_compat_syscall() &&
2319	    ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2320	     *len != sizeof(tmp)))
2321		return compat_do_ebt_get_ctl(sk, cmd, user, len);
2322#endif
2323
2324	if (copy_from_user(&tmp, user, sizeof(tmp)))
2325		return -EFAULT;
2326
2327	tmp.name[sizeof(tmp.name) - 1] = '\0';
2328
2329	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2330	if (!t)
2331		return ret;
2332
2333	switch (cmd) {
2334	case EBT_SO_GET_INFO:
2335	case EBT_SO_GET_INIT_INFO:
2336		if (*len != sizeof(struct ebt_replace)) {
2337			ret = -EINVAL;
2338			mutex_unlock(&ebt_mutex);
2339			break;
2340		}
2341		if (cmd == EBT_SO_GET_INFO) {
2342			tmp.nentries = t->private->nentries;
2343			tmp.entries_size = t->private->entries_size;
2344			tmp.valid_hooks = t->valid_hooks;
2345		} else {
2346			tmp.nentries = t->table->nentries;
2347			tmp.entries_size = t->table->entries_size;
2348			tmp.valid_hooks = t->table->valid_hooks;
2349		}
2350		mutex_unlock(&ebt_mutex);
2351		if (copy_to_user(user, &tmp, *len) != 0) {
2352			ret = -EFAULT;
2353			break;
2354		}
2355		ret = 0;
2356		break;
2357
2358	case EBT_SO_GET_ENTRIES:
2359	case EBT_SO_GET_INIT_ENTRIES:
2360		ret = copy_everything_to_user(t, user, len, cmd);
2361		mutex_unlock(&ebt_mutex);
2362		break;
2363
2364	default:
2365		mutex_unlock(&ebt_mutex);
2366		ret = -EINVAL;
2367	}
2368
2369	return ret;
2370}
2371
2372static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2373		unsigned int len)
2374{
2375	struct net *net = sock_net(sk);
2376	int ret;
2377
2378	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2379		return -EPERM;
2380
2381	switch (cmd) {
2382	case EBT_SO_SET_ENTRIES:
2383#ifdef CONFIG_COMPAT
2384		if (in_compat_syscall())
2385			ret = compat_do_replace(net, arg, len);
2386		else
2387#endif
2388			ret = do_replace(net, arg, len);
2389		break;
2390	case EBT_SO_SET_COUNTERS:
2391#ifdef CONFIG_COMPAT
2392		if (in_compat_syscall())
2393			ret = compat_update_counters(net, arg, len);
2394		else
2395#endif
2396			ret = update_counters(net, arg, len);
2397		break;
2398	default:
2399		ret = -EINVAL;
2400	}
2401	return ret;
2402}
2403
2404static struct nf_sockopt_ops ebt_sockopts = {
2405	.pf		= PF_INET,
2406	.set_optmin	= EBT_BASE_CTL,
2407	.set_optmax	= EBT_SO_SET_MAX + 1,
2408	.set		= do_ebt_set_ctl,
2409	.get_optmin	= EBT_BASE_CTL,
2410	.get_optmax	= EBT_SO_GET_MAX + 1,
2411	.get		= do_ebt_get_ctl,
2412	.owner		= THIS_MODULE,
2413};
2414
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2415static int __init ebtables_init(void)
2416{
2417	int ret;
2418
2419	ret = xt_register_target(&ebt_standard_target);
2420	if (ret < 0)
2421		return ret;
2422	ret = nf_register_sockopt(&ebt_sockopts);
2423	if (ret < 0) {
2424		xt_unregister_target(&ebt_standard_target);
2425		return ret;
2426	}
2427
 
 
 
 
 
 
 
2428	return 0;
2429}
2430
2431static void __exit ebtables_fini(void)
2432{
2433	nf_unregister_sockopt(&ebt_sockopts);
2434	xt_unregister_target(&ebt_standard_target);
 
2435}
2436
2437EXPORT_SYMBOL(ebt_register_table);
2438EXPORT_SYMBOL(ebt_unregister_table);
2439EXPORT_SYMBOL(ebt_do_table);
2440module_init(ebtables_init);
2441module_exit(ebtables_fini);
2442MODULE_LICENSE("GPL");