From patchwork Thu Mar 16 18:16:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Wang X-Patchwork-Id: 664978 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3CE4C7618A for ; Thu, 16 Mar 2023 18:17:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231126AbjCPSRR (ORCPT ); Thu, 16 Mar 2023 14:17:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230102AbjCPSRM (ORCPT ); Thu, 16 Mar 2023 14:17:12 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.196]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2DD015BA4; Thu, 16 Mar 2023 11:17:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=UGlVF hKvm+OVmmeFuzi8z9E6fZiz9gpJF1uOXlesQSc=; b=EuNaBNv2s8eZ0qUNoxPS9 2jbHZTb72rYNh5lqGA/zJLDl3JPjsSzCelDvC+APKaE6/qg6BzmYX5YObYU/tayu KlKjZFUuyoH9KhgBywyJO6iohbSvjQdgCY8br1amrJGgVlZJVx4ymKdFMbTTXn+k LxJCZCNv884NRGiD01//+U= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g0-4 (Coremail) with SMTP id _____wA33PX4XBNkYs_bAA--.57770S2; Fri, 17 Mar 2023 02:16:24 +0800 (CST) From: Zheng Wang To: gregkh@linuxfoundation.org Cc: skhan@linuxfoundation.org, p.zabel@pengutronix.de, biju.das.jz@bp.renesas.com, phil.edworthy@renesas.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, yoshihiro.shimoda.uh@renesas.com, Zheng Wang Subject: [PATCH v8] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition Date: Fri, 17 Mar 2023 02:16:23 +0800 Message-Id: <20230316181623.1603914-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wA33PX4XBNkYs_bAA--.57770S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Zr45Xr15Jr4rCF4UXr4DXFb_yoW8ZF4UpF WDKFW5Ar4rJFWqqay7GFykZF1rCF9rKry7ZFWxKw48uF1rG3y8XryIqF45CFnrJFZ3AF40 vayDu34jqa47u37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zina9DUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiGgI0U1aEEmcYkgAAsS Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org In renesas_usb3_probe, role_work is bound with renesas_usb3_role_work. renesas_usb3_start will be called to start the work. If we remove the driver which will call usbhs_remove, there may be an unfinished work. The possible sequence is as follows: Fix it by canceling the work before cleanup in the renesas_usb3_remove. Note that removing a driver is a root-only operation, and should never happen. CPU0 CPU1 renesas_usb3_role_work renesas_usb3_remove usb_role_switch_unregister device_unregister kfree(sw) free usb3->role_sw usb_role_switch_set_role //use usb3->role_sw This bug was found by static analysis. Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch") Signed-off-by: Zheng Wang Reviewed-by: Yoshihiro Shimoda --- v8: - replace | with spaces to make line up suggested by Greg KH v7: - add more details about how the bug was found suggested by Shuah v6: - beautify the format and add note suggested by Greg KH v5: - fix typo v4: - add Reviewed-by label and resubmit v4 suggested by Greg KH v3: - modify the commit message to make it clearer suggested by Yoshihiro Shimoda v2: - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda --- drivers/usb/gadget/udc/renesas_usb3.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c index bee6bceafc4f..a301af66bd91 100644 --- a/drivers/usb/gadget/udc/renesas_usb3.c +++ b/drivers/usb/gadget/udc/renesas_usb3.c @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev) debugfs_remove_recursive(usb3->dentry); device_remove_file(&pdev->dev, &dev_attr_role); + cancel_work_sync(&usb3->role_work); usb_role_switch_unregister(usb3->role_sw); usb_del_gadget_udc(&usb3->gadget);