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[209.132.180.67]) by mx.google.com with ESMTP id 5si3350970edy.95.2019.10.17.22.05.25; Thu, 17 Oct 2019 22:05:48 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=NzqcPwWL; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389491AbfJPWUC (ORCPT + 99 others); Wed, 16 Oct 2019 18:20:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:43300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437617AbfJPVxz (ORCPT ); Wed, 16 Oct 2019 17:53:55 -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 23D5121925; Wed, 16 Oct 2019 21:53:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571262835; bh=02Z9UXwgMEO0Eqk3cS/X3mhPJ6TaJuHCY2mB028kJWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NzqcPwWL1ojfXiP85EiKMZjX6Nx/HwcQXwAa07FBrc3Q40Qj4dnXYc8Eh/xRoTP73 9dVkm+RMdk9npqIGe5Nf1DJgEI0vQ6RY15OcNPZ0ut1kg15KQHWvA80YhtGUAzGC7G 4oUZO/HgZiBZvQutnjpSJGvjBMbeVtrr5+9TphhU= 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 4.4 42/79] USB: iowarrior: fix use-after-free on disconnect Date: Wed, 16 Oct 2019 14:50:17 -0700 Message-Id: <20191016214804.538019762@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214729.758892904@linuxfoundation.org> References: <20191016214729.758892904@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 @@ -898,8 +898,6 @@ 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); @@ -910,8 +908,7 @@ 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 , @@ -921,8 +918,10 @@ 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); }