[PATCH 2/2] usbnet: cleanup after bind() in probe()

[Luis Henriques]

From: Oliver Neukum <oneukum at suse.com>

In case bind() works, but a later error forces bailing
in probe() in error cases work and a timer may be scheduled.
They must be killed. This fixes an error case related to
the double free reported in
http://www.spinics.net/lists/netdev/msg367669.html
and needs to go on top of Linus' fix to cdc-ncm.

Signed-off-by: Oliver Neukum <ONeukum at suse.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 1666984c8625b3db19a9abc298931d35ab7bc64b)
CVE-2016-3951
BugLink: https://bugs.launchpad.net/bugs/1567191
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/usb/usbnet.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 0744bf2ef2d6..c2ea4e5666fb 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1766,6 +1766,13 @@ out3:
 	if (info->unbind)
 		info->unbind (dev, udev);
 out1:
+	/* subdrivers must undo all they did in bind() if they
+	 * fail it, but we may fail later and a deferred kevent
+	 * may trigger an error resubmitting itself and, worse,
+	 * schedule a timer. So we kill it all just in case.
+	 */
+	cancel_work_sync(&dev->kevent);
+	del_timer_sync(&dev->delay);
 	free_netdev(net);
 out:
 	return status;