From mboxrd@z Thu Jan 1 00:00:00 1970 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 84F0AC6FD19 for ; Thu, 16 Mar 2023 19:09:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230107AbjCPTJ6 (ORCPT ); Thu, 16 Mar 2023 15:09:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229620AbjCPTJ4 (ORCPT ); Thu, 16 Mar 2023 15:09:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 315AB1A95D; Thu, 16 Mar 2023 12:09:55 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BA13D620ED; Thu, 16 Mar 2023 19:09:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5B83C433EF; Thu, 16 Mar 2023 19:09:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678993794; bh=8KIkizWvlt2DPvDyEONJ3fFdM3lCyHdam/VFNf/SBQo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HIdDWkf2BaGbG44tmdrdbzxf/o4IekXDsbNkKR/XNTGD50+CJpTHJlZIyN47Wa/o5 4CnjtZkwxosA/o/PT6TuoEaUQ6mBjBeIouoz0oODGHSAhAmBn8lfNHW7RfAIb8HIqz +AO6lsSMVbHOfzv74S5FCo8APTsg/v6KNoS966FA= Date: Thu, 16 Mar 2023 20:09:51 +0100 From: "gregkh@linuxfoundation.org" To: Zheng Hacker Cc: Shuah Khan , Zheng Wang , "valentina.manea.m@gmail.com" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "1395428693sheep@gmail.com" <1395428693sheep@gmail.com>, "alex000young@gmail.com" Subject: Re: [PATCH v2] usbip: vudc: Fix use after free bug in vudc_remove due to race condition Message-ID: References: <20230316180940.1601515-1-zyytlz.wz@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 17, 2023 at 02:27:05AM +0800, Zheng Hacker wrote: > 在 2023年3月17日星期五，Shuah Khan 写道： > > > On 3/16/23 12:09, Zheng Wang wrote: > > > >> 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. > >> > > > > Tell me which static analysis tool did you use to find this and > > the output from the tool. > > > This is found by codeql，the rule is complicated. It finally found > there is no timer stop behavior in remove function. When using tools like this, you are required to follow the rules in Documentation/process/researcher-guidelines.rst Please do so here. thanks, greg k-h