[PATCH net-next v2 1/4] net: sched: em_ipt: match only on ip/ipv6 traffic

From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
To: netdev@vger.kernel.org
Cc: roopa@cumulusnetworks.com, pablo@netfilter.org,
	xiyou.wangcong@gmail.com, davem@davemloft.net, jiri@resnulli.us,
	jhs@mojatatu.com, eyal.birger@gmail.com,
	Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Subject: [PATCH net-next v2 1/4] net: sched: em_ipt: match only on ip/ipv6 traffic
Date: Wed, 26 Jun 2019 18:56:12 +0300	[thread overview]
Message-ID: <20190626155615.16639-2-nikolay@cumulusnetworks.com> (raw)
In-Reply-To: <20190626155615.16639-1-nikolay@cumulusnetworks.com>

Restrict matching only to ip/ipv6 traffic and make sure we can use the
headers, otherwise matches will be attempted on any protocol which can
be unexpected by the xt matches. Currently policy supports only ipv4/6.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
---
 net/sched/em_ipt.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/sched/em_ipt.c b/net/sched/em_ipt.c
index 243fd22f2248..64dbafe4e94c 100644
--- a/net/sched/em_ipt.c
+++ b/net/sched/em_ipt.c
@@ -185,6 +185,19 @@ static int em_ipt_match(struct sk_buff *skb, struct tcf_ematch *em,
 	struct nf_hook_state state;
 	int ret;
 
+	switch (tc_skb_protocol(skb)) {
+	case htons(ETH_P_IP):
+		if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
+			return 0;
+		break;
+	case htons(ETH_P_IPV6):
+		if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
+			return 0;
+		break;
+	default:
+		return 0;
+	}
+
 	rcu_read_lock();
 
 	if (skb->skb_iif)
-- 
2.20.1

