From: Florian Westphal <fw@xxxxxxxxx>
syzbot reports just another NULL deref crash because of missing test
for presence of the attribute.
Reported-by: syzbot+cf23983d697c26c34f60@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: b96af92d6eaf9fadd ("netfilter: nf_tables: implement Passive OS fingerprint module in nft_osf")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nft_osf.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index f54d6ae15bb1..b42247aa48a9 100644
--- a/net/netfilter/nft_osf.c
+++ b/net/netfilter/nft_osf.c
@@ -61,6 +61,9 @@ static int nft_osf_init(const struct nft_ctx *ctx,
int err;
u8 ttl;
+ if (!tb[NFTA_OSF_DREG])
+ return -EINVAL;
+
if (tb[NFTA_OSF_TTL]) {
ttl = nla_get_u8(tb[NFTA_OSF_TTL]);
if (ttl > 2)
--
2.11.0
