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[49/93] netfilter: xtables: compat out of scope fix

From:  Greg KH <gregkh-AT-suse.de>
To:  linux-kernel-AT-vger.kernel.org, stable-AT-kernel.org
Subject:  [49/93] netfilter: xtables: compat out of scope fix
Date:  Fri, 19 Feb 2010 08:29:42 -0800
Cc:  stable-review-AT-kernel.org, torvalds-AT-linux-foundation.org, akpm-AT-linux-foundation.org, alan-AT-lxorguk.ukuu.org.uk, Alexey Dobriyan <adobriyan-AT-gmail.com>, Patrick McHardy <kaber-AT-trash.net>
Archive-link:  Article, Thread

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alexey Dobriyan <adobriyan@gmail.com>

commit 14c7dbe043d01a83a30633ab6b109ba2ac61d9f7 upstream.

As per C99 6.2.4(2) when temporary table data goes out of scope,
the behaviour is undefined:

	if (compat) {
		struct foo tmp;
		...
		private = &tmp;
	}
	[dereference private]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 net/ipv4/netfilter/arp_tables.c |    4 ++--
 net/ipv4/netfilter/ip_tables.c  |    4 ++--
 net/ipv6/netfilter/ip6_tables.c |    4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -925,10 +925,10 @@ static int get_info(struct net *net, voi
 	if (t && !IS_ERR(t)) {
 		struct arpt_getinfo info;
 		const struct xt_table_info *private = t->private;
-
 #ifdef CONFIG_COMPAT
+		struct xt_table_info tmp;
+
 		if (compat) {
-			struct xt_table_info tmp;
 			ret = compat_table_info(private, &tmp);
 			xt_compat_flush_offsets(NFPROTO_ARP);
 			private = &tmp;
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1132,10 +1132,10 @@ static int get_info(struct net *net, voi
 	if (t && !IS_ERR(t)) {
 		struct ipt_getinfo info;
 		const struct xt_table_info *private = t->private;
-
 #ifdef CONFIG_COMPAT
+		struct xt_table_info tmp;
+
 		if (compat) {
-			struct xt_table_info tmp;
 			ret = compat_table_info(private, &tmp);
 			xt_compat_flush_offsets(AF_INET);
 			private = &tmp;
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1164,10 +1164,10 @@ static int get_info(struct net *net, voi
 	if (t && !IS_ERR(t)) {
 		struct ip6t_getinfo info;
 		const struct xt_table_info *private = t->private;
-
 #ifdef CONFIG_COMPAT
+		struct xt_table_info tmp;
+
 		if (compat) {
-			struct xt_table_info tmp;
 			ret = compat_table_info(private, &tmp);
 			xt_compat_flush_offsets(AF_INET6);
 			private = &tmp;




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