netfilter: nft_osf: check for TCP packet before further processing

[ Upstream commit 8f518d43f89ae00b9cf5460e10b91694944ca1a8 ]

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: b96af92d6e ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pablo Neira Ayuso 2021-06-10 20:20:31 +02:00 committed by Greg Kroah-Hartman
parent 4759c55ff1
commit a3f1e8e316
1 changed files with 5 additions and 0 deletions

View File

@ -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) {