xfrm: fix the if_id check in changelink

BugLink: https://bugs.launchpad.net/bugs/1964361
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@denx.de>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index 57448fc519fcd9b6b09f66bcaf996ceb9b34f8d8..4e3c62d1ad9e91aead01b88d3c0ebe824bc29235 100644 (file)
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -673,12 +673,12 @@ static int xfrmi_changelink(struct net_device *dev, struct nlattr *tb[],
        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);