geneve: fix an uninitialized value in geneve_changelink()

geneve_nl2info() sets 'df' conditionally, so we have to
initialize it by copying the value from existing geneve
device in geneve_changelink().

Fixes: 56c09de347e4 ("geneve: allow changing DF behavior after creation")
Reported-by: syzbot+7ebc2e088af5e4c0c9fa@syzkaller.appspotmail.com
Cc: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 4661ef8..dec52b7 100644 (file)
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1615,11 +1615,11 @@ static int geneve_changelink(struct net_device *dev, struct nlattr *tb[],
                             struct netlink_ext_ack *extack)
 {
        struct geneve_dev *geneve = netdev_priv(dev);
+       enum ifla_geneve_df df = geneve->df;
        struct geneve_sock *gs4, *gs6;
        struct ip_tunnel_info info;
        bool metadata;
        bool use_udp6_rx_checksums;
-       enum ifla_geneve_df df;
        bool ttl_inherit;
        int err;