Patch "macvlan: Fix one possible double free" has been added to the 4.9-stable tree

Patch "macvlan: Fix one possible double free" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    macvlan: Fix one possible double free

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     macvlan-fix-one-possible-double-free.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Feb 28 16:13:29 CET 2018
From: Gao Feng <gfree.wind@vip.163.com>
Date: Tue, 26 Dec 2017 21:44:32 +0800
Subject: macvlan: Fix one possible double free

From: Gao Feng <gfree.wind@vip.163.com>


[ Upstream commit d02fd6e7d2933ede6478a15f9e4ce8a93845824e ]

Because the macvlan_uninit would free the macvlan port, so there is one
double free case in macvlan_common_newlink. When the macvlan port is just
created, then register_netdevice or netdev_upper_dev_link failed and they
would invoke macvlan_uninit. Then it would reach the macvlan_port_destroy
which triggers the double free.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/macvlan.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1377,9 +1377,14 @@ int macvlan_common_newlink(struct net *s
 	return 0;
 
 unregister_netdev:
+	/* macvlan_uninit would free the macvlan port */
 	unregister_netdevice(dev);
+	return err;
 destroy_macvlan_port:
-	if (create)
+	/* the macvlan port may be freed by macvlan_uninit when fail to register.
+	 * so we destroy the macvlan port only when it's valid.
+	 */
+	if (create && macvlan_port_get_rtnl(dev))
 		macvlan_port_destroy(port->dev);
 	return err;
 }


Patches currently in stable-queue which might be from gfree.wind@vip.163.com are

queue-4.9/macvlan-fix-one-possible-double-free.patch