tun_dst: Fix potential NULL dereference

In tun_dst_unclone() the return value of skb_metadata_dst() is checked
for being NULL after it is dereferenced. Fix this by moving the
dereference after the NULL check.

Found by the Coverity scanner (CID 1338068).

Fixes: fc4099f17240 ("openvswitch: Fix egress tunnel info.")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index ce009710120ca8b541615b237a329ee089ec357b..6816f0fa5693dc275e1e4997375f29b5d99f7b64 100644 (file)
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h
@@ -63,12 +63,13 @@ static inline struct metadata_dst *tun_rx_dst(int md_size)
 static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb)
 {
        struct metadata_dst *md_dst = skb_metadata_dst(skb);
-       int md_size = md_dst->u.tun_info.options_len;
+       int md_size;
        struct metadata_dst *new_md;
 
        if (!md_dst)
                return ERR_PTR(-EINVAL);
 
+       md_size = md_dst->u.tun_info.options_len;
        new_md = metadata_dst_alloc(md_size, GFP_ATOMIC);
        if (!new_md)
                return ERR_PTR(-ENOMEM);