From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757854AbeAHO0C (ORCPT + 1 other); Mon, 8 Jan 2018 09:26:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:38679 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757769AbeAHO0A (ORCPT ); Mon, 8 Jan 2018 09:26:00 -0500 From: Oliver Neukum To: khoroshilov@ispras.ru, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, mchehab@s-opensource.com Cc: Oliver Neukum , stable@vger.kernel.org Subject: [PATCH] media: usbtv: prevent double free in error case Date: Mon, 8 Jan 2018 15:21:07 +0100 Message-Id: <20180108142107.29045-1-oneukum@suse.com> X-Mailer: git-send-email 2.13.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 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 Signed-off-by: Oliver Neukum CC: stable@vger.kernel.org --- drivers/media/usb/usbtv/usbtv-core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/usb/usbtv/usbtv-core.c b/drivers/media/usb/usbtv/usbtv-core.c index 127f8a0c098b..0c2e628e8723 100644 --- a/drivers/media/usb/usbtv/usbtv-core.c +++ b/drivers/media/usb/usbtv/usbtv-core.c @@ -112,6 +112,8 @@ static int usbtv_probe(struct usb_interface *intf, return 0; usbtv_audio_fail: + /* we must not free at this point */ + usb_get_dev(usbtv->udev); usbtv_video_free(usbtv); usbtv_video_fail: -- 2.13.6