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

media: usbtv: prevent double free in error case

to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: media-usbtv-prevent-double-free-in-error-case.patch and it can be found in the queue-3.18 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 50e7044535537b2a54c7ab798cd34c7f6d900bd2 Mon Sep 17 00:00:00 2001

From: Oliver Neukum oneukum@suse.com Date: Mon, 8 Jan 2018 09:21:07 -0500 Subject: media: usbtv: prevent double free in error case

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:

Patches currently in stable-queue which might be from oneukum@suse.com are

queue-3.18/media-usbtv-prevent-double-free-in-error-case.patch