[PATCH 3.14 118/140] ip6_tunnel: fix potential NULL pointer dereference

From: Greg Kroah-Hartman
Date: Thu May 29 2014 - 01:09:36 EST


3.14-stable review patch. If anyone has any objections, please let me know.

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

From: Susant Sahani <susant@xxxxxxxxxx>

[ Upstream commit c8965932a2e3b70197ec02c6741c29460279e2a8 ]

The function ip6_tnl_validate assumes that the rtnl
attribute IFLA_IPTUN_PROTO always be filled . If this
attribute is not filled by the userspace application
kernel get crashed with NULL pointer dereference. This
patch fixes the potential kernel crash when
IFLA_IPTUN_PROTO is missing .

Signed-off-by: Susant Sahani <susant@xxxxxxxxxx>
Acked-by: Thomas Graf <tgraf@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_tunnel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1564,7 +1564,7 @@ static int ip6_tnl_validate(struct nlatt
{
u8 proto;

- if (!data)
+ if (!data || !data[IFLA_IPTUN_PROTO])
return 0;

proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);


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