From patchwork Mon Sep 21 16:27:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 263574 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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 0FFA6C43468 for ; Mon, 21 Sep 2020 17:03:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D021E2073A for ; Mon, 21 Sep 2020 17:03:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707781; bh=zf7oB3PkR2yVlda4d6EQa8QkhzF5w3CdKqr2FqhnXlQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1f8BgfYzVOytxxcKJ/rsMBKv2uOW5+S4eMODTvv/KiHpJFb+gr4k0xyeLc3YbXwF9 L5moCK6bt7Pgs3VU7XPXt+Ke2qob07l3qfTFKyejqisF1VkAwgSV5+BmQBp9PlDKze 7qULhi9VmXlpQxkLnLPoeXBRsakxDbLPEXHhWTN8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729428AbgIURCu (ORCPT ); Mon, 21 Sep 2020 13:02:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:38590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728759AbgIUQhu (ORCPT ); Mon, 21 Sep 2020 12:37:50 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D11AB239D1; Mon, 21 Sep 2020 16:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706269; bh=zf7oB3PkR2yVlda4d6EQa8QkhzF5w3CdKqr2FqhnXlQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kWZsBjo/zDQANAfWyJ9hdtgK/nVqWrDadn0mZP0N1z5gWoiMOaNxdNlqO7OnzOwxw 2NgeSgfBEtwuGXsxUdoP9Ou9bcP300UZkoUGtttJVpKb0aZWb2wbfD+rxd0stAjupn 7cZ3qLHGm+Bjl8M7z3G5jEvOHnkYdmKoxLRwohOc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.14 33/94] iio:light:max44000 Fix timestamp alignment and prevent data leak. Date: Mon, 21 Sep 2020 18:27:20 +0200 Message-Id: <20200921162037.074629662@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit 523628852a5f5f34a15252b2634d0498d3cfb347 upstream. One of a class of bugs pointed out by Lars in a recent review. iio_push_to_buffers_with_timestamp assumes the buffer used is aligned to the size of the timestamp (8 bytes). This is not guaranteed in this driver which uses a 16 byte array of smaller elements on the stack. As Lars also noted this anti pattern can involve a leak of data to userspace and that indeed can happen here. We close both issues by moving to a suitable structure in the iio_priv(). This data is allocated with kzalloc so no data can leak appart from previous readings. It is necessary to force the alignment of ts to avoid the padding on x86_32 being different from 64 bit platorms (it alows for 4 bytes aligned 8 byte types. Fixes: 06ad7ea10e2b ("max44000: Initial triggered buffer support") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/light/max44000.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/drivers/iio/light/max44000.c +++ b/drivers/iio/light/max44000.c @@ -78,6 +78,11 @@ struct max44000_data { struct mutex lock; struct regmap *regmap; + /* Ensure naturally aligned timestamp */ + struct { + u16 channels[2]; + s64 ts __aligned(8); + } scan; }; /* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */ @@ -492,7 +497,6 @@ static irqreturn_t max44000_trigger_hand struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct max44000_data *data = iio_priv(indio_dev); - u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */ int index = 0; unsigned int regval; int ret; @@ -502,17 +506,17 @@ static irqreturn_t max44000_trigger_hand ret = max44000_read_alsval(data); if (ret < 0) goto out_unlock; - buf[index++] = ret; + data->scan.channels[index++] = ret; } if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) { ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val); if (ret < 0) goto out_unlock; - buf[index] = regval; + data->scan.channels[index] = regval; } mutex_unlock(&data->lock); - iio_push_to_buffers_with_timestamp(indio_dev, buf, + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED;