From patchwork Fri Mar 17 09:55:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Wang X-Patchwork-Id: 664971 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 9437CC74A5B for ; Fri, 17 Mar 2023 09:56:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229754AbjCQJ4A (ORCPT ); Fri, 17 Mar 2023 05:56:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229665AbjCQJz7 (ORCPT ); Fri, 17 Mar 2023 05:55:59 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.199]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6F2D4DF71B; Fri, 17 Mar 2023 02:55:57 -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=rwAEm +cWbN5Z7WMrvgzF8eqPAyvKEM6UBaWx8s5mWAM=; b=n/kj1aMJq/S1ynzCYLvih dC/y+E1Xr6cF7tp5O2gCwpXtFVmhhF7X+eRoXyifIsk/xoCvaB1elMhFXKHNkV7g yzCIoTO9cHcUR8x55v8zpgdv54lsNH2Gs1wFhc9GqZvPpT3TiWvSqRqmGTQrNkkg 8B8+7duuO2+H6eRIO4eA3U= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g3-1 (Coremail) with SMTP id _____wCni237OBRk5O1cAQ--.3872S2; Fri, 17 Mar 2023 17:55:07 +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 v9] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition Date: Fri, 17 Mar 2023 17:55:05 +0800 Message-Id: <20230317095505.2599838-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wCni237OBRk5O1cAQ--.3872S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Zr45Xr15Jry8JFW3Zr4UCFg_yoW8tFWrpF WDKFW5Aw4rJFWqv3y7GFykZF1rCFnrKr1UZFWxGw48uF1rG3y0qry2qa15Cr9rJFZ3AF40 vayDu34jva47ua7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziznQ8UUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiGh01U1aEEm6rjwAAsr 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: 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 The usb3->role_sw could be freed under such circumstance and use in usb_role_switch_set_role. This bug was found by static analysis. And note that removing a driver is a root-only operation, and should never happen in normal case. But the attacker can directly remove the device which will also triggering remove function. Fix it by canceling the work before cleanup in the renesas_usb3_remove. Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch") Signed-off-by: Zheng Wang Reviewed-by: Yoshihiro Shimoda --- v9: - append with more information suggested by Greg KH 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);