From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Thu, 10 Jun 2021 18:20:31 +0000 (+0200)
Subject: netfilter: nft_osf: check for TCP packet before further processing
X-Git-Tag: io_uring-5.14-2021-07-09~10^2^2~22^2~5
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=8f518d43f89ae00b9cf5460e10b91694944ca1a8;p=linux-block.git

netfilter: nft_osf: check for TCP packet before further processing

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@netfilter.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index ac61f708b82d..d82677e83400 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;
+		return;
+	}
+
 	tcp = skb_header_pointer(skb, ip_hdrlen(skb),
 				 sizeof(struct tcphdr), &_tcph);
 	if (!tcp) {