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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 D9A59C433DF for ; Sun, 9 Aug 2020 17:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD89720723 for ; Sun, 9 Aug 2020 17:24:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596993857; bh=2ndZ4RLMsOgn6Iz0bO56Ta8CRVyf7+vErsirG2d9Nzk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=AC0TXxNueHgecQ9CHvvUMxma7mW49duuWDlKUawJ8UxMbh+fDtBP3KqBdNKWu9vK3 /yb2OQ4GFJhFs76eZk3cMqfaoBn6TcAYel54Fxps3zX8Z64ScovVWrNQ1VN4YJgdTr VZXDjh8UArpOHAN16t9MLwdX+7oNGPOo/pYa82MU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726207AbgHIRYR (ORCPT ); Sun, 9 Aug 2020 13:24:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:54856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726296AbgHIRYR (ORCPT ); Sun, 9 Aug 2020 13:24:17 -0400 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (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 8E6D6206C3; Sun, 9 Aug 2020 17:24:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596993856; bh=2ndZ4RLMsOgn6Iz0bO56Ta8CRVyf7+vErsirG2d9Nzk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vY7tCfm3S9J4LTBlAOoC3ZBTPCoFupzoDKFO8ugI6Sg8tuNQGEk89U4C9UJR6RIYl N8jE/UNsGBLcaIFEl8TqvN1OaLMxuOC6x5jkGDG7995rigQXCW/vzPLWNfLuvQZX/R LctUQeqYV1rFTnSDCy/0u/DNKrCVx7jhbiGpPy0k= Date: Sun, 9 Aug 2020 18:24:13 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron Subject: Re: [PATCH v3 09/27] iio:light:max44000 Fix timestamp alignment and prevent data leak. Message-ID: <20200809182413.7791e236@archlinux> In-Reply-To: <20200722155103.979802-10-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> <20200722155103.979802-10-jic23@kernel.org> X-Mailer: Claws Mail 3.17.6 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Wed, 22 Jul 2020 16:50:45 +0100 Jonathan Cameron wrote: > From: Jonathan Cameron > > 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 Applied and marked for stable Thanks, Jonathan > --- > drivers/iio/light/max44000.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c > index aa8ed1e3e89a..b8e721bced5b 100644 > --- a/drivers/iio/light/max44000.c > +++ b/drivers/iio/light/max44000.c > @@ -75,6 +75,11 @@ > 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 */ > @@ -488,7 +493,6 @@ static irqreturn_t max44000_trigger_handler(int irq, void *p) > 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; > @@ -498,17 +502,17 @@ static irqreturn_t max44000_trigger_handler(int irq, void *p) > 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;