3.18-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum oneukum@suse.com
commit 50e7044535537b2a54c7ab798cd34c7f6d900bd2 upstream.
Quoting the original report:
It looks like there is a double-free vulnerability in Linux usbtv driver on an error path of usbtv_probe function. When audio registration fails, usbtv_video_free function ends up freeing usbtv data structure, which gets freed the second time under usbtv_video_fail label.
usbtv_audio_fail:
usbtv_video_free(usbtv); =>
v4l2_device_put(&usbtv->v4l2_dev);
=> v4l2_device_put
=> kref_put
=> v4l2_device_release
=> usbtv_release (CALLBACK)
=> kfree(usbtv) (1st time)
usbtv_video_fail:
usb_set_intfdata(intf, NULL);
usb_put_dev(usbtv->udev);
kfree(usbtv); (2nd time)
So, as we have refcounting, use it
Reported-by: Yavuz, Tuba tuba@ece.ufl.edu Signed-off-by: Oliver Neukum oneukum@suse.com CC: stable@vger.kernel.org Signed-off-by: Hans Verkuil hans.verkuil@cisco.com Signed-off-by: Mauro Carvalho Chehab mchehab@s-opensource.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/usb/usbtv/usbtv-core.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/media/usb/usbtv/usbtv-core.c +++ b/drivers/media/usb/usbtv/usbtv-core.c @@ -95,6 +95,8 @@ static int usbtv_probe(struct usb_interf return 0;
usbtv_audio_fail: + /* we must not free at this point */ + usb_get_dev(usbtv->udev); usbtv_video_free(usbtv);
usbtv_video_fail: