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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 12DBEC4743C for ; Mon, 21 Jun 2021 13:58:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF74161042 for ; Mon, 21 Jun 2021 13:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbhFUOBH (ORCPT ); Mon, 21 Jun 2021 10:01:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229736AbhFUOBH (ORCPT ); Mon, 21 Jun 2021 10:01:07 -0400 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6105CC061574 for ; Mon, 21 Jun 2021 06:58:52 -0700 (PDT) Received: by mail-pj1-x102d.google.com with SMTP id m15-20020a17090a5a4fb029016f385ffad0so58023pji.0 for ; Mon, 21 Jun 2021 06:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=p3A1VusKl6uX5GDoa6CBzjWStucuaSh9zBU2efKSA4M=; b=jmhGkTlQPswKDP1sWz/jSx4qs8MD2RTWzs0MPwAaMF6xGp20sZnTQyqkFi8eqpn1xO qyLmUK5Rpla9H7zx/vPmcvQAq/cwt9pUA19W8DN0TTlk45XLmmD4/DnRaAqTj0KEACYR HGMNj7SzN4ySGRWa7YVKj4nIXiFXCM5M70cys++iTTDSCMcu6rYm90ePOynGl9gyxZVD 5CXTS3CfCmwzTYKcciB9Vj2WomIgKU/Mgva76Is5KQ81LOmzMKJDxz8XHkXwcpPl3+DU JYCAipj3uXCXnBCfGUtMM4NbWZggn6VQGQvK5Hrrd4yNSZMUrPyM34y4HG1ld7pH5R+r TlVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=p3A1VusKl6uX5GDoa6CBzjWStucuaSh9zBU2efKSA4M=; b=DPnd/aFdKeLWZx48uUhRcF4oQLgcx6IQgCG143eksbxJXqnPmD/xbV+zZm761IUtsh 31dRWcyan7aSnS0HxULybxsBZknHS0jnYXfgHv40uqWBIh2E7/JhOsbk0f7vRgtFeDhj e6aK2aL78OUNp5pjBgYxv5a64SarGHjngbhLEtvGmCERFle0RxffOElUcvYyhQe/PJPD 9Xqya7t9d2XyZjPro6udENxuhRhdFYidcaYlNxeS8Ug5qDdxz5h3Leoew2cNoDhYVHNY RbgOeGiv+a72Lqo7dz04hIIHRemz0x/HaNEqEuMUrV/nxv2/zX3xWbL8JVp8ROm7FoBa CtQw== X-Gm-Message-State: AOAM5336EAx6OfmWISd/xYkG4GjY4d0HZ3p7U9KoDg6LahmLKUcyBSFF eOpAtxMFDWSg3utdt8kAC9uZrMNM/m7Am2vaiNA= X-Google-Smtp-Source: ABdhPJzaqN4ilINnJWZPW2RprNE4aqQ0lJojT5IMQKrOduUIehXVZa3fFT0+yAo9L0DNv1On6mYkUptZXDyfc9v5V6I= X-Received: by 2002:a17:90a:bc89:: with SMTP id x9mr27628788pjr.228.1624283931949; Mon, 21 Jun 2021 06:58:51 -0700 (PDT) MIME-Version: 1.0 References: <20210621132354.57127-1-hdegoede@redhat.com> In-Reply-To: <20210621132354.57127-1-hdegoede@redhat.com> From: Andy Shevchenko Date: Mon, 21 Jun 2021 16:58:15 +0300 Message-ID: Subject: Re: [PATCH] platform/x86: think-lmi: Return EINVAL when kbdlang gets set to a 0 length string To: Hans de Goede Cc: Mark Gross , Andy Shevchenko , Mark Pearson , Platform Driver Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org On Mon, Jun 21, 2021 at 4:24 PM Hans de Goede wrote: > > Commit 0ddcf3a6b442 ("platform/x86: think-lmi: Avoid potential read before > start of the buffer") moved the lengt == 0 up to before stripping the '\n' length > which typically gets added when users echo a value to a sysfs-attribute > from the shell. > > This avoids a potential buffer-underrun, but it also causes a behavioral > change, prior to this change "echo > kbdlang", iow writing just a single > '\n' would result in an EINVAL error, but after the change this gets > accepted setting kbdlang to an empty string. And why is it a problem? I mean since we haven't yet released this in any of the kernels, the ABIU can be adjusted one way or another. > Re-add the length != 0 check after stripping the '\n' to reject this > again, as before the change. -- With Best Regards, Andy Shevchenko