The osf expression only supports for TCP packets, add a upfront sanity
check to skip packet parsing if this is not a TCP packet.
Fixes: b96af92d6eaf ("netfilter: nf_tables: implement Passive OS fingerprint module in nft_osf")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nft_osf.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index ac61f708b82d..4e6c65eaf567 100644
--- a/net/netfilter/nft_osf.c
+++ b/net/netfilter/nft_osf.c
@@ -28,6 +28,11 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
struct nf_osf_data data;
struct tcphdr _tcph;
+ if (pkt->tprot != IPPROTO_TCP) {
+ regs->verdict.code = NFT_BREAK;
+ break;
+ }
+
tcp = skb_header_pointer(skb, ip_hdrlen(skb),
sizeof(struct tcphdr), &_tcph);
if (!tcp) {
--
2.20.1
