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Commit fc1221b3 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: x_tables: add compat version of xt_check_entry_offsets 



32bit rulesets have different layout and alignment requirements, so once
more integrity checks get added to xt_check_entry_offsets it will reject
well-formed 32bit rulesets.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent a08e4e19

include/linux/netfilter/x_tables.h

+3 −0
Original line number Diff line number Diff line
@@ -494,6 +494,9 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 
				unsigned int *size);

int xt_compat_target_to_user(const struct xt_entry_target *t,

			     void __user **dstptr, unsigned int *size);

int xt_compat_check_entry_offsets(const void *base,

				  unsigned int target_offset,

				  unsigned int next_offset);



#endif /* CONFIG_COMPAT */

#endif /* _X_TABLES_H */

net/ipv4/netfilter/arp_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -1254,7 +1254,8 @@ check_compat_entry_size_and_hooks(struct compat_arpt_entry *e, 
	if (!arp_checkentry(&e->arp))

		return -EINVAL;



	ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);

	ret = xt_compat_check_entry_offsets(e, e->target_offset,

					    e->next_offset);

	if (ret)

		return ret;

net/ipv4/netfilter/ip_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -1513,7 +1513,8 @@ check_compat_entry_size_and_hooks(struct compat_ipt_entry *e, 
	if (!ip_checkentry(&e->ip))

		return -EINVAL;



	ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);

	ret = xt_compat_check_entry_offsets(e,

					    e->target_offset, e->next_offset);

	if (ret)

		return ret;

net/ipv6/netfilter/ip6_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -1525,7 +1525,8 @@ check_compat_entry_size_and_hooks(struct compat_ip6t_entry *e, 
	if (!ip6_checkentry(&e->ipv6))

		return -EINVAL;



	ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);

	ret = xt_compat_check_entry_offsets(e,

					    e->target_offset, e->next_offset);

	if (ret)

		return ret;

net/netfilter/x_tables.c

+22 −0
Original line number Diff line number Diff line
@@ -539,6 +539,27 @@ int xt_compat_match_to_user(const struct xt_entry_match *m, 
	return 0;

}

EXPORT_SYMBOL_GPL(xt_compat_match_to_user);



int xt_compat_check_entry_offsets(const void *base,

				  unsigned int target_offset,

				  unsigned int next_offset)

{

	const struct compat_xt_entry_target *t;

	const char *e = base;



	if (target_offset + sizeof(*t) > next_offset)

		return -EINVAL;



	t = (void *)(e + target_offset);

	if (t->u.target_size < sizeof(*t))

		return -EINVAL;



	if (target_offset + t->u.target_size > next_offset)

		return -EINVAL;



	return 0;

}

EXPORT_SYMBOL(xt_compat_check_entry_offsets);

#endif /* CONFIG_COMPAT */



/**
@@ -549,6 +570,7 @@ EXPORT_SYMBOL_GPL(xt_compat_match_to_user); 
 * @next_offset: the arp/ip/ip6_t->next_offset

 *

 * validates that target_offset and next_offset are sane.

 * Also see xt_compat_check_entry_offsets for CONFIG_COMPAT version.

 *

 * The arp/ip/ip6t_entry structure @base must have passed following tests:

 * - it must point to a valid memory location