[PATCH 5.4 17/62] s390/qeth: fix L2 header access in qeth_l3_osa_features_check()

Greg Kroah-Hartman
2021-01-15T12:54:03Z

From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit f9c4845385c8f6631ebd5dddfb019ea7a285fba4 ]

ip_finish_output_gso() may call .ndo_features_check() even before the
skb has a L2 header. This conflicts with qeth_get_ip_version()'s attempt
to inspect the L2 header via vlan_eth_hdr().

Switch to vlan_get_protocol(), as already used further down in the
common qeth_features_check() path.

Fixes: f13ade199391 ("s390/qeth: run non-offload L3 traffic over common xmit path")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/s390/net/qeth_l3_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2114,7 +2114,7 @@ static netdev_features_t qeth_l3_osa_fea
struct net_device *dev,
netdev_features_t features)
{
- if (qeth_get_ip_version(skb) != 4)
+ if (vlan_get_protocol(skb) != htons(ETH_P_IP))
features &= ~NETIF_F_HW_VLAN_CTAG_TX;
return qeth_features_check(skb, dev, features);
}