sit: fix an oops when IFLA_IPTUN_PROTO is not set

The use of this attribute has been added in 32b8a8e59c9c (sit: add IPv4 over
IPv4 support). It is optional, by default proto is IPPROTO_IPV6.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 6cee844678e2418c2fefc84ddbfd9c34584ea613..f639866b3dcfb51e3c0fc22e0298fd5cf1816f8e 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1296,7 +1296,7 @@ static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
 {
        u8 proto;
 
-       if (!data)
+       if (!data || !data[IFLA_IPTUN_PROTO])
                return 0;
 
        proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);