From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Mon, 15 Jul 2019 10:00:20 +0000 (+0200)
Subject: xfrm interface: avoid corruption on changelink
X-Git-Tag: v4.19.89~43
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f04f067aaa38246cc8d7392ee27da80ed8d19289;p=platform%2Fkernel%2Flinux-rpi.git

xfrm interface: avoid corruption on changelink

commit e9e7e85d75f3731079ffd77c1a66f037aef04fe7 upstream.

The new parameters must not be stored in the netdev_priv() before
validation, it may corrupt the interface. Note also that if data is NULL,
only a memset() is done.

$ ip link add xfrm1 type xfrm dev lo if_id 1
$ ip link add xfrm2 type xfrm dev lo if_id 2
$ ip link set xfrm1 type xfrm dev lo if_id 2
RTNETLINK answers: File exists
$ ip -d link list dev xfrm1
5: xfrm1@lo: <NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/none 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 minmtu 68 maxmtu 1500
    xfrm if_id 0x2 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

=> "if_id 0x2"

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Julien Floret <julien.floret@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index e1265fd..c811158 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -674,12 +674,12 @@ static int xfrmi_changelink(struct net_device *dev, struct nlattr *tb[],
 			   struct nlattr *data[],
 			   struct netlink_ext_ack *extack)
 {
-	struct xfrm_if *xi = netdev_priv(dev);
 	struct net *net = dev_net(dev);
+	struct xfrm_if_parms p;
+	struct xfrm_if *xi;
 
-	xfrmi_netlink_parms(data, &xi->p);
-
-	xi = xfrmi_locate(net, &xi->p);
+	xfrmi_netlink_parms(data, &p);
+	xi = xfrmi_locate(net, &p);
 	if (!xi) {
 		xi = netdev_priv(dev);
 	} else {
@@ -687,7 +687,7 @@ static int xfrmi_changelink(struct net_device *dev, struct nlattr *tb[],
 			return -EEXIST;
 	}
 
-	return xfrmi_update(xi, &xi->p);
+	return xfrmi_update(xi, &p);
 }
 
 static size_t xfrmi_get_size(const struct net_device *dev)