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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FC26C63697 for ; Tue, 17 Nov 2020 20:11:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB2A020707 for ; Tue, 17 Nov 2020 20:10:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jZM/9RMq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731187AbgKQUKj (ORCPT ); Tue, 17 Nov 2020 15:10:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725771AbgKQUKh (ORCPT ); Tue, 17 Nov 2020 15:10:37 -0500 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4911C0613CF; Tue, 17 Nov 2020 12:10:37 -0800 (PST) Received: by mail-pj1-x1043.google.com with SMTP id f12so1074992pjp.4; Tue, 17 Nov 2020 12:10:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=bmbJEohduwIPhnsFk/cfq3mtQUXTQveb1Iq9VOsGuMU=; b=jZM/9RMqhYJxtofwet0Zn613Rc8plW58KNwfn1ShIQjROJ5GlqgnuRc3EY2GyZA/2H eK/0gn7vkgWnlC+1vElgkJOMFlZVdbCNoxfVb4awATNTv3IMPsz2OCIz9XcR7KyhXRq/ HY/F5JTv5PY16HTaPfCAwv9DdfYiaxYN+OXAZhJ+UXyZdAzrXNMpZnVfwgWVkPbHfXk+ cewSFd0i0ynorooarcBhYRx+Ht+blCi36jqFc7aqMGBvwdNJX3PfYn61oHxx0FUvACiJ THQJ5IB4xxrVnJyLaVIGzTQ3Hyy1qsaHvy8oyIpzlomQmm/tYMGehXj+zkcksv/ZPzhz 6FJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=bmbJEohduwIPhnsFk/cfq3mtQUXTQveb1Iq9VOsGuMU=; b=pUN8BczV0iaN07Q4uM1XB4j2lpabc1nI24eO3Th24efxpL+CzC6APSotWCqivwDVsf zhfK7BJ1h+dOBGyQWF+Uhd4Z37Q3qZMFoRjwQMbMjchhWcliIQ5Jymz/oRebix7blgCU WppAEn/9vHBEJzkMWMhJ7ryz64WKjBCsuZ9icv74ELyovdvv77pxB06625616LuO7BeU HXj8Gzz1Ua5Rev80Yk6vSCN6j3klhX4mYF1jtso+ycjBpmONIwZRYfLq9S7CtQP7NrVr TPpxh1PqZs+fLbVX3THLjB/wBVMBeAmeFJlLpVoxOmnV7odngafpD+Vsv2O5/WIzI3MU bTTA== X-Gm-Message-State: AOAM532n5SG2tIv2od76EYAqdj7g8No5hKKj2yXR5HM3elPqFOhnKygO RpzVgJhOB2CR3hxocXmoRMY= X-Google-Smtp-Source: ABdhPJz5uefSitZ/i0yMZ12HAGdsOeL40fwWRL8vg1C3nO+a8kN0tYqDfbzee8n5UI0eCMDZxR/hRg== X-Received: by 2002:a17:90a:fa93:: with SMTP id cu19mr735753pjb.117.1605643837076; Tue, 17 Nov 2020 12:10:37 -0800 (PST) Received: from dtor-ws ([2620:15c:202:201:a6ae:11ff:fe11:fcc3]) by smtp.gmail.com with ESMTPSA id h32sm19167326pgl.36.2020.11.17.12.10.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Nov 2020 12:10:36 -0800 (PST) Date: Tue, 17 Nov 2020 12:10:34 -0800 From: Dmitry Torokhov To: Yang Yingliang Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org Subject: Re: [PATCH] Input: sunkbd - fix UAF in sunkbd_reinit() Message-ID: <20201117201034.GA2009714@dtor-ws> References: <20201117132751.14863-1-yangyingliang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201117132751.14863-1-yangyingliang@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Yang, On Tue, Nov 17, 2020 at 09:27:51PM +0800, Yang Yingliang wrote: > > After sunkbd->tq is added to workqueue, before scheduled work finish, sunkbd is > freed by sunkbd_disconnect(), when sunkbd is used in sunkbd_reinit(), it causes > a UAF. Fix this by calling flush_scheduled_work() before free sunkbd. > > This fixes CVE-2020-25669. > > Signed-off-by: Yang Yingliang > --- > drivers/input/keyboard/sunkbd.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/input/keyboard/sunkbd.c b/drivers/input/keyboard/sunkbd.c > index 27126e621eb6..b6222896acdf 100644 > --- a/drivers/input/keyboard/sunkbd.c > +++ b/drivers/input/keyboard/sunkbd.c > @@ -316,6 +316,7 @@ static void sunkbd_disconnect(struct serio *serio) > { > struct sunkbd *sunkbd = serio_get_drvdata(serio); > > + flush_scheduled_work(); This is unfortunately racy as we may get interrupt and reschedule the work again before we get to disabling the port. It is properly fixed by 77e70d351db7de07a46ac49b87a6c3c7a60fca7e. > sunkbd_enable(sunkbd, false); > input_unregister_device(sunkbd->dev); > serio_close(serio); > -- > 2.17.1 > Thanks. -- Dmitry