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 A88E3C6FD1F for ; Thu, 16 Mar 2023 18:09:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230457AbjCPSJ5 (ORCPT ); Thu, 16 Mar 2023 14:09:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230460AbjCPSJt (ORCPT ); Thu, 16 Mar 2023 14:09:49 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.216]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1134469CEC; Thu, 16 Mar 2023 11:09:47 -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=A0H0V 2O0pfEGsz1NojrmtfRRySfrSnyGWaGppw4kXvg=; b=BYUYQ0taeZkEQpbkqguYX WARVIRKN50zK5t5w10IhWbjRiosnjoirUe/ebP0+kZN/3ACR6I1ityzVYLtwQmyW bQMexNW32PQU3+7hkyShp7HxR1PK0Vjc6e3pk7K3rFK4pJOKbwpUwYStPMF0UbJJ bHUdwU7b20vc8Sx8/Wyiwo= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g4-1 (Coremail) with SMTP id _____wC3y0FmWxNk2oMdAQ--.18175S2; Fri, 17 Mar 2023 02:09:42 +0800 (CST) From: Zheng Wang To: valentina.manea.m@gmail.com Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, skhan@linuxfoundation.org, Zheng Wang Subject: [PATCH v2] usbip: vudc: Fix use after free bug in vudc_remove due to race condition Date: Fri, 17 Mar 2023 02:09:40 +0800 Message-Id: <20230316180940.1601515-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: _____wC3y0FmWxNk2oMdAQ--.18175S2 X-Coremail-Antispam: 1Uf129KBjvJXoWrtF1UGFy5Jw45ZF18GrWkXrb_yoW8JryUpr ZxWFWxCr4xGFs2qa17Ar90vryrJw43tryY9rWIkayxurW3Ar4UXas0yF1jkFWxAFZaqr43 tF4vvwn5WFykAaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziID7fUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiQgg0U1aEEsHvmQAAsa Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In vudc_probe, it calls init_vudc_hw, which bound &udc->timer with v_timer. When it calls usbip_sockfd_store, it will call v_start_timer to start the timer work. When we call vudc_remove to remove the driver, theremay be a sequence as follows: Fix it by shutdown the timer work before cleanup in vudc_remove. Note that removing a driver is a root-only operation, and should never happen. CPU0 CPU1 |v_timer vudc_remove | kfree(udc); | //free shost | |udc->gadget |//use This bug was found by static analysis. Fixes: b6a0ca111867 ("usbip: vudc: Add UDC specific ops") Signed-off-by: Zheng Wang --- v2: - add more details about how the bug was found suggested by Shuah --- drivers/usb/usbip/vudc_dev.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c index 2bc428f2e261..33d0991755bb 100644 --- a/drivers/usb/usbip/vudc_dev.c +++ b/drivers/usb/usbip/vudc_dev.c @@ -633,6 +633,7 @@ int vudc_remove(struct platform_device *pdev) { struct vudc *udc = platform_get_drvdata(pdev); + timer_shutdown_sync(&udc->timer); usb_del_gadget_udc(&udc->gadget); cleanup_vudc_hw(udc); kfree(udc); -- 2.25.1