[PATCH AUTOSEL 5.4 091/107] netfilter: nft_tunnel: fix null-attribute check

From: Sasha Levin
Date: Fri Jan 24 2020 - 09:20:27 EST


From: Florian Westphal <fw@xxxxxxxxx>

[ Upstream commit 1c702bf902bd37349f6d91cd7f4b372b1e46d0ed ]

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: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netfilter/nft_tunnel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nft_tunnel.c b/net/netfilter/nft_tunnel.c
index 3d4c2ae605a8e..d89c7c5530309 100644
--- a/net/netfilter/nft_tunnel.c
+++ b/net/netfilter/nft_tunnel.c
@@ -76,7 +76,7 @@ static int nft_tunnel_get_init(const struct nft_ctx *ctx,
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;

--
2.20.1