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 1BCAEC38145 for ; Thu, 8 Sep 2022 08:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231508AbiIHIKn (ORCPT ); Thu, 8 Sep 2022 04:10:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231460AbiIHIK0 (ORCPT ); Thu, 8 Sep 2022 04:10:26 -0400 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1776171BF9 for ; Thu, 8 Sep 2022 01:10:16 -0700 (PDT) Received: by mail-ej1-f51.google.com with SMTP id bj12so36134137ejb.13 for ; Thu, 08 Sep 2022 01:10:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date; bh=Bj+mLV6GrBWexFrxYIG1e6IyShZ1xzdoaItMhP88h9U=; b=DYD9H3kNrMMX1v9aGFkGmSJPdsk6yOOj902oYmmJTRFDo8Zgz0C+fXTLI+cVbBneaW W5HRO4GJUA42yo3BG3yqmWE33xPhkHRRyuRJvOU0SAAdRzJ8aEkm8oY71WoeVQ6rZNP9 8xLHgyDa7KgTEL+MbBPt3gw6lRNErmtmjB9z8eeTenUWbX/2qMwpwOpYI9Ucq3aLG3TD Wv6JbU3cKcsPBSYTa35EfNYrc3667+DnZueyvVexl+T9/SPYWRuqAqHWuUlOdVaFR3+Y 1gdupqjpyWi3FdTDxBNJo+3la3WJKO2qN65K0nzuRXTzipzkVwvsvKtwJcVe5LkYEeNd pgSQ== X-Gm-Message-State: ACgBeo0HQ7DF61FiQ8ZKazOvDNv6/mD9Gc8mfAM3O7Ami13e4Gt3Bpfu F7VqkT+RfbGxTzoTUqWtyNtCEoeO630= X-Google-Smtp-Source: AA6agR6k1Um0VmSoHS4As+BSzUbpu1RWDNGgrfO4GNVwN+5EjmH2dmPTHcms2++xzuWuoe8RrY7guw== X-Received: by 2002:a17:907:2c44:b0:770:8623:66c4 with SMTP id hf4-20020a1709072c4400b00770862366c4mr4364644ejc.3.1662624614380; Thu, 08 Sep 2022 01:10:14 -0700 (PDT) Received: from [192.168.1.49] (185-219-167-24-static.vivo.cz. [185.219.167.24]) by smtp.gmail.com with ESMTPSA id b5-20020aa7c6c5000000b00450206d9dfbsm783233eds.84.2022.09.08.01.10.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Sep 2022 01:10:13 -0700 (PDT) Message-ID: <6236da54-c651-9dc7-f5ce-824be96b3e9d@kernel.org> Date: Thu, 8 Sep 2022 10:10:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH] tty: vt: add a bounds checking in vt_do_kdgkb_ioctl() To: Hangyu Hua , gregkh@linuxfoundation.org, changlianzhi@uniontech.com, dmitry.torokhov@gmail.com Cc: linux-kernel@vger.kernel.org References: <20220908075403.27930-1-hbh25y@gmail.com> Content-Language: en-US From: Jiri Slaby In-Reply-To: <20220908075403.27930-1-hbh25y@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08. 09. 22, 9:54, Hangyu Hua wrote: > As array_index_nospec's comments indicateļ¼Œa bounds checking need to add > before calling array_index_nospec. > > Signed-off-by: Hangyu Hua > --- > drivers/tty/vt/keyboard.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c > index be8313cdbac3..b9845455df79 100644 > --- a/drivers/tty/vt/keyboard.c > +++ b/drivers/tty/vt/keyboard.c > @@ -2067,6 +2067,9 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) > if (get_user(kb_func, &user_kdgkb->kb_func)) > return -EFAULT; > > + if (kb_func >= MAX_NR_FUNC) kb_func is unsigned char and MAX_NR_FUNC is 256. So this should be eliminated by the compiler anyway. But the check might be a good idea if we ever decide to support more keys. But will/can we? I am not so sure, so adding it right now is kind of superfluous. In any way we'd need to introduce a completely different iterface/ioctls. > + return -EFAULT; EINVAL would be more appropriate, IMO. > + > kb_func = array_index_nospec(kb_func, MAX_NR_FUNC); > > switch (cmd) { thanks, -- js suse labs