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 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:
media-usbtv-prevent-double-free-in-error-case.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@xxxxxxxxxxxxxxx> know about it.
>From 50e7044535537b2a54c7ab798cd34c7f6d900bd2 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@xxxxxxxx>
Date: Mon, 8 Jan 2018 09:21:07 -0500
Subject: media: usbtv: prevent double free in error case
From: Oliver Neukum <oneukum@xxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -109,6 +109,8 @@ 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@xxxxxxxx are
queue-4.9/media-usbtv-prevent-double-free-in-error-case.patch