[PATCH 4.19 061/103] netfilter: nft_tunnel: fix null-attribute check

[Greg Kroah-Hartman]

From: Florian Westphal <fw@xxxxxxxxx>

commit 1c702bf902bd37349f6d91cd7f4b372b1e46d0ed upstream.

else we get null deref when one of the attributes is missing, both
must be non-null.

Reported-by: syzbot+76d0b80493ac881ff77b@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: aaecfdb5c5dd8ba ("netfilter: nf_tables: match on tunnel metadata")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/netfilter/nft_tunnel.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netfilter/nft_tunnel.c
+++ b/net/netfilter/nft_tunnel.c
@@ -56,7 +56,7 @@ static int nft_tunnel_get_init(const str
 	struct nft_tunnel *priv = nft_expr_priv(expr);
 	u32 len;
 
-	if (!tb[NFTA_TUNNEL_KEY] &&
+	if (!tb[NFTA_TUNNEL_KEY] ||
 	    !tb[NFTA_TUNNEL_DREG])
 		return -EINVAL;