netdev - [PATCH] ipvlan: add the check of ip header checksum

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Date:   Tue, 21 Jul 2020 21:09:22 +0800
From:   guodeqing <geffrey.guo@...wei.com>
To:     <davem@...emloft.net>
CC:     <kuba@...nel.org>, <maheshb@...gle.com>, <edumazet@...gle.com>,
        <netdev@...r.kernel.org>, <geffrey.guo@...wei.com>
Subject: [PATCH] ipvlan: add the check of ip header checksum

The ip header checksum can be error in the following steps.
$ ip netns add ns1
$ ip link add gw link eth0 type ipvlan
$ ip addr add 168.16.0.1/24 dev gw
$ ip link set dev gw up
$ ip link add ip1 link eth0 type ipvlan
$ ip link set ip1 netns ns1
$ ip netns exec ns1 ip link set ip1 up
$ ip netns exec ns1 ip addr add 168.16.0.2/24 dev ip1
$ ip netns exec ns1 tc qdisc add dev ip1 root netem corrupt 50%
$ ip netns exec ns1 ping 168.16.0.1

The ip header of a packet maybe modified when it steps in
ipvlan_process_v4_outbound because of the netem, the corruptted
packets should be dropped.

Here I add the check of ip header to drop the corruptted packets
and to avoid a problem in some cases.

Signed-off-by: guodeqing <geffrey.guo@...wei.com>
---
 drivers/net/ipvlan/ipvlan_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 8801d09..22cef89 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -428,6 +428,12 @@ static int ipvlan_process_v4_outbound(struct sk_buff *skb)
 		.saddr = ip4h->saddr,
 	};

+	if (ip4h->ihl < 5)
+		goto err;
+
+	if (unlikely(ip_fast_csum((u8 *)ip4h, ip4h->ihl)))
+		goto err;
+
 	rt = ip_route_output_flow(net, &fl4, NULL);
 	if (IS_ERR(rt))
 		goto err;
-- 
2.7.4