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=-8.6 required=3.0 tests=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 6F3F9C433DF for ; Sun, 24 May 2020 15:34:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AC2B207DA for ; Sun, 24 May 2020 15:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590334482; bh=wT+ESqG7vZqzvtm4IF1yCazLxtRoy8QN9SSj2Wr1oNw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=D/77q7RyjcV5X9uZv9uOE+rUD+0LEe/9PubV4jfYyWilad3PTBljwQEdAxJWEA0l8 MquzPBlgqL04E8CDN3xca8PQFMSJXyho0ynaj/SoOHsu377BuLFldieV0llGxqw1KW NYaH99Z81b19yy3wU3Jt6zJ6OpFPAqmKQH+y8mw8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727899AbgEXPel (ORCPT ); Sun, 24 May 2020 11:34:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:38298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727068AbgEXPel (ORCPT ); Sun, 24 May 2020 11:34:41 -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 50754207CB; Sun, 24 May 2020 15:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590334481; bh=wT+ESqG7vZqzvtm4IF1yCazLxtRoy8QN9SSj2Wr1oNw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=K4RlZyCoPWC56P5DgXEeaNWi/roVGgZo9wiqsTi4+juzjzKgxc3UPxdUKEdnCkQlR sx9uVO+wSuOoQf/MSOXWhtREKBwlpKcq57GHt9S/3Ag0farf0aGNvy0sZFFyU1gFrb UeZlF0JW+3udyEfuwwEfeigEueBfoqs7H5L6+RUU= Date: Sun, 24 May 2020 16:34:32 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Jonathan Cameron , Lars-Peter Clausen , "Andrew F . Davis" Subject: Re: [PATCH 08/11] iio:health:afe4404 Fix timestamp alignment and prevent data leak. Message-ID: <20200524163432.2c1407e5@archlinux> In-Reply-To: <20200517173000.220819-9-jic23@kernel.org> References: <20200517173000.220819-1-jic23@kernel.org> <20200517173000.220819-9-jic23@kernel.org> X-Mailer: Claws Mail 3.17.5 (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 Sun, 17 May 2020 18:29:57 +0100 jic23@kernel.org 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 40 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() data with alignment > explicitly requested. This data is allocated with kzalloc so no > data can leak appart from previous readings. > > Fixes: 87aec56e27ef ("iio: health: Add driver for the TI AFE4404 heart monitor") > Reported-by: Lars-Peter Clausen > Signed-off-by: Jonathan Cameron > Cc: Andrew F. Davis Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan > --- > drivers/iio/health/afe4404.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c > index e728bbb21ca8..cebb1fd4d0b1 100644 > --- a/drivers/iio/health/afe4404.c > +++ b/drivers/iio/health/afe4404.c > @@ -83,6 +83,7 @@ static const struct reg_field afe4404_reg_fields[] = { > * @regulator: Pointer to the regulator for the IC > * @trig: IIO trigger for this device > * @irq: ADC_RDY line interrupt number > + * @buffer: Used to construct a scan to push to the iio buffer. > */ > struct afe4404_data { > struct device *dev; > @@ -91,6 +92,7 @@ struct afe4404_data { > struct regulator *regulator; > struct iio_trigger *trig; > int irq; > + s32 buffer[10] __aligned(8); > }; > > enum afe4404_chan_id { > @@ -328,17 +330,17 @@ static irqreturn_t afe4404_trigger_handler(int irq, void *private) > struct iio_dev *indio_dev = pf->indio_dev; > struct afe4404_data *afe = iio_priv(indio_dev); > int ret, bit, i = 0; > - s32 buffer[10]; > > for_each_set_bit(bit, indio_dev->active_scan_mask, > indio_dev->masklength) { > ret = regmap_read(afe->regmap, afe4404_channel_values[bit], > - &buffer[i++]); > + &afe->buffer[i++]); > if (ret) > goto err; > } > > - iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp); > + iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer, > + pf->timestamp); > err: > iio_trigger_notify_done(indio_dev->trig); >