From 7eaecf7963c1c8f62d62c6a8e7c439b0e7f2d365 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sat, 18 Jan 2020 11:27:25 +0100 Subject: netfilter: nft_osf: add missing check for DREG attribute syzbot reports just another NULL deref crash because of missing test for presence of the attribute. Reported-by: syzbot+cf23983d697c26c34f60@syzkaller.appspotmail.com Fixes: b96af92d6eaf9fadd ("netfilter: nf_tables: implement Passive OS fingerprint module in nft_osf") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- 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) -- cgit