[PATCH 4.19 19/51] xfrm: fix the if_id check in changelink

[Greg Kroah-Hartman]

From: Antony Antony <antony.antony@xxxxxxxxxxx>

commit 6d0d95a1c2b07270870e7be16575c513c29af3f1 upstream.

if_id will be always 0, because it was not yet initialized.

Fixes: 8dce43919566 ("xfrm: interface with if_id 0 should return error")
Reported-by: Pavel Machek <pavel@xxxxxxx>
Signed-off-by: Antony Antony <antony.antony@xxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/xfrm/xfrm_interface.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -698,12 +698,12 @@ static int xfrmi_changelink(struct net_d
 	struct net *net = xi->net;
 	struct xfrm_if_parms p = {};
 
+	xfrmi_netlink_parms(data, &p);
 	if (!p.if_id) {
 		NL_SET_ERR_MSG(extack, "if_id must be non zero");
 		return -EINVAL;
 	}
 
-	xfrmi_netlink_parms(data, &p);
 	xi = xfrmi_locate(net, &p);
 	if (!xi) {
 		xi = netdev_priv(dev);