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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 82223C433DB for ; Wed, 13 Jan 2021 09:31:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 261212339D for ; Wed, 13 Jan 2021 09:31:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727056AbhAMJa5 (ORCPT ); Wed, 13 Jan 2021 04:30:57 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43666 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726803AbhAMJa4 (ORCPT ); Wed, 13 Jan 2021 04:30:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610530169; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4NzzU9gTPLBRDuVevAdWIrw84i9fziQn8LtNJFPsNd0=; b=IvLG2/qQM43Yehh2SjzkinyVH03TQgxhFzsXy7lwjqiCLpIP2PJOmBsG3x1z6G6O0HHq9+ xWoPlHnLWuzJ1fpLs4J4q1/yTczEJSHLCDFnlMKHUoAWyiX+vKApmNI7I7iiYCjy//qlcl gqYOd0qkNDSVfKcJlksAQ6l+TJ0LRcU= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-23-jW5Spf7DPym3xS6IHBiAmw-1; Wed, 13 Jan 2021 04:29:27 -0500 X-MC-Unique: jW5Spf7DPym3xS6IHBiAmw-1 Received: by mail-ej1-f70.google.com with SMTP id r26so666943ejx.6 for ; Wed, 13 Jan 2021 01:29:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4NzzU9gTPLBRDuVevAdWIrw84i9fziQn8LtNJFPsNd0=; b=sYn+0cyzxIHNrYrRfbOdZEgXrbgv5q7J9ZBUjTBbpmeVot9wpfTf227paH9O9ToaJP OkIekY4eIvZfI2pojtC0BdLg9tRB7SsjlwHCbv7EfnCCiVAmquvBjALg23NrJP3yneKg dHC142nY4OHHmI0+2zA/9hB/KeZHu0WbxDoxKfhM7uEvFRzhS9xVsn4wSUjk3P9Z+7Tb GtbmmA9lG5yCiSSiUTgU51/rPrdozMhrgyCaF+ptRLRVkxrpXu7Pu7kvqhPWlcLsXxKJ LRc4fHsTwdKbduhnjmfHpbourJqlbDIc7+eQwSiVU4aohtfU70BIjrnsu9gWHVwwo7S7 kgGg== X-Gm-Message-State: AOAM533W/B1eM8ODf+cwFIb0FN7sLueut6P7qt19GdqoE/D3FX1Vava1 lvQ4Uo8HK/EN6lDiaZlVWEMGPndaHK25Q4ajsu+QjgsVBsB1/C6x/K9bMGUU4neP/zsQ9HvrHXD N15XfJOhScum4XiWeJrvzFBeuJkmeqCQB7Q== X-Received: by 2002:a05:6402:1383:: with SMTP id b3mr1018146edv.100.1610530166182; Wed, 13 Jan 2021 01:29:26 -0800 (PST) X-Google-Smtp-Source: ABdhPJw08XHHl+TDZXjj1je5Q6TE0RpJVI0OZmCedBYN1dWUmsBxearRIitgOcyOVfvefIbxc6D4MA== X-Received: by 2002:a05:6402:1383:: with SMTP id b3mr1018139edv.100.1610530166059; Wed, 13 Jan 2021 01:29:26 -0800 (PST) Received: from x1.localdomain (2001-1c00-0c1e-bf00-37a3-353b-be90-1238.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:37a3:353b:be90:1238]) by smtp.gmail.com with ESMTPSA id bq20sm469449ejb.64.2021.01.13.01.29.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 13 Jan 2021 01:29:25 -0800 (PST) Subject: Re: [PATCH] platform/surface: aggregator: prevent information leak in ssam_cdev_request() To: Dan Carpenter , Maximilian Luz Cc: Mark Gross , platform-driver-x86@vger.kernel.org, kernel-janitors@vger.kernel.org References: From: Hans de Goede Message-ID: Date: Wed, 13 Jan 2021 10:29:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Hi, On 1/13/21 9:16 AM, Dan Carpenter wrote: > If copy_struct_from_user() fails at the start of the function then this > function calls put_user(rsp.length, &r->response.length) before > "rsp.length" is set to zero. That is a potential security issue because > it discloses kernel stack data to user space. > > Fixes: 178f6ab77e61 ("platform/surface: Add Surface Aggregator user-space interface") > Signed-off-by: Dan Carpenter Thank you for your patch, another fix for this was already submitted: https://patchwork.kernel.org/project/platform-driver-x86/patch/20210111154851.325404-2-luzmaximilian@gmail.com/ So I'm dropping this patch from my queue. Regards, Hans > --- > drivers/platform/surface/surface_aggregator_cdev.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c > index 340d15b148b9..05e9eb118d76 100644 > --- a/drivers/platform/surface/surface_aggregator_cdev.c > +++ b/drivers/platform/surface/surface_aggregator_cdev.c > @@ -67,7 +67,7 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) > struct ssam_cdev_request __user *r; > struct ssam_cdev_request rqst; > struct ssam_request spec; > - struct ssam_response rsp; > + struct ssam_response rsp = {}; > const void __user *plddata; > void __user *rspdata; > int status = 0, ret = 0, tmp; > @@ -96,8 +96,6 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) > spec.flags |= SSAM_REQUEST_UNSEQUENCED; > > rsp.capacity = rqst.response.length; > - rsp.length = 0; > - rsp.pointer = NULL; > > /* Get request payload from user-space. */ > if (spec.length) { >