Don't potentially dereference NULL in net/dcb/dcbnl.c:dcbnl_getapp()

nla_nest_start() may return NULL. If it does then we'll blow up in
nla_nest_end() when we dereference the pointer.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 712ca026040..d5074a56728 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -626,6 +626,9 @@ static int dcbnl_getapp(struct net_device *netdev, struct nlattr **tb,
         dcb->cmd = DCB_CMD_GAPP;
 
         app_nest = nla_nest_start(dcbnl_skb, DCB_ATTR_APP);
+        if (!app_nest)
+                goto out_cancel;
+
         ret = nla_put_u8(dcbnl_skb, DCB_APP_ATTR_IDTYPE, idtype);
         if (ret)
                 goto out_cancel;