From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69031ECE599 for ; Wed, 16 Oct 2019 22:07:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32FFE207FF for ; Wed, 16 Oct 2019 22:07:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571263633; bh=hAsqppvURYM9GWpczI9rGWlTdjnFjUFXQk2AxTJM8U8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HWzvuj+KQ9MkRnefpm3blE9dXuki3KYP5ykd+6OuAM6X0bhKUCHaDOBcj1SRcODOy 99VBV6JAIr4IFNkG2f/2L3z8ie9KugBRSv2ci7HkG5zY/ZSLdtzoVQtwTBQE27GxMq VYWwYw8VCCA7kk8vx3Um+3NhuMh6SbfDcJkhvEOs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729379AbfJPWHL (ORCPT ); Wed, 16 Oct 2019 18:07:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:51696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388728AbfJPV6Q (ORCPT ); Wed, 16 Oct 2019 17:58:16 -0400 Received: from localhost (unknown [192.55.54.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 25D8920872; Wed, 16 Oct 2019 21:58:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571263096; bh=hAsqppvURYM9GWpczI9rGWlTdjnFjUFXQk2AxTJM8U8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S1XVAlPmFSYX+she1GXYovLEHjHO14p+71+zSowO8CQsTq+s1pQLKe66VG9DCsKpU /eyQX9EZC1Ic9rHsP8+KO7XmipZMm2P8A2N8fCr1C4P9fWAqUqPbkJ8iCX4sd87VDJ fUgCruHhDt9mbOG/ZEJuD8a7zD8yMlZLuHUud8nU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com, Johan Hovold Subject: [PATCH 5.3 018/112] USB: iowarrior: fix use-after-free on disconnect Date: Wed, 16 Oct 2019 14:50:10 -0700 Message-Id: <20191016214848.809765930@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214844.038848564@linuxfoundation.org> References: <20191016214844.038848564@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold commit edc4746f253d907d048de680a621e121517f484b upstream. A recent fix addressing a deadlock on disconnect introduced a new bug by moving the present flag out of the critical section protected by the driver-data mutex. This could lead to a racing release() freeing the driver data before disconnect() is done with it. Due to insufficient locking a related use-after-free could be triggered also before the above mentioned commit. Specifically, the driver needs to hold the driver-data mutex also while checking the opened flag at disconnect(). Fixes: c468a8aa790e ("usb: iowarrior: fix deadlock on disconnect") Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.") Cc: stable # 2.6.21 Reported-by: syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20191009104846.5925-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/iowarrior.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/drivers/usb/misc/iowarrior.c +++ b/drivers/usb/misc/iowarrior.c @@ -866,8 +866,6 @@ static void iowarrior_disconnect(struct dev = usb_get_intfdata(interface); mutex_lock(&iowarrior_open_disc_lock); usb_set_intfdata(interface, NULL); - /* prevent device read, write and ioctl */ - dev->present = 0; minor = dev->minor; mutex_unlock(&iowarrior_open_disc_lock); @@ -878,8 +876,7 @@ static void iowarrior_disconnect(struct mutex_lock(&dev->mutex); /* prevent device read, write and ioctl */ - - mutex_unlock(&dev->mutex); + dev->present = 0; if (dev->opened) { /* There is a process that holds a filedescriptor to the device , @@ -889,8 +886,10 @@ static void iowarrior_disconnect(struct usb_kill_urb(dev->int_in_urb); wake_up_interruptible(&dev->read_wait); wake_up_interruptible(&dev->write_wait); + mutex_unlock(&dev->mutex); } else { /* no process is using the device, cleanup now */ + mutex_unlock(&dev->mutex); iowarrior_delete(dev); }