From nobody Tue Feb 10 12:42:23 2026 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 D6257C7618B for ; Fri, 17 Mar 2023 09:56:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229560AbjCQJ4B (ORCPT ); Fri, 17 Mar 2023 05:56:01 -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 Content-Transfer-Encoding: quoted-printable 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-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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_rol= e_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 whic= h 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 r= ole 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 Shimo= da 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); =20 + cancel_work_sync(&usb3->role_work); usb_role_switch_unregister(usb3->role_sw); =20 usb_del_gadget_udc(&usb3->gadget); --=20 2.25.1