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 B9BCCC433DF for ; Sun, 9 Aug 2020 17:36:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 94B79206CD for ; Sun, 9 Aug 2020 17:36:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994606; bh=fqvCUxbPL0VuyK2/JldCW/ot+bbQbu5DhzCk451T4NY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=P40+htggxS4Mz2PJ65jxlucRGHNzXyKGKRvxqZawooiXpTwhA/RX2FhGQql3TPNwb CYRThhmGY1vidd6ZJJ3fqp1D8sxWInXmHPoeBpS0RJ4ks2fW8i3k4rQMoMzOfTc4mb ZYAu41ryA5E9XRNM/3DSw4q9Y3R15EjB85azgxl0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726229AbgHIRgq (ORCPT ); Sun, 9 Aug 2020 13:36:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60542 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbgHIRgq (ORCPT ); Sun, 9 Aug 2020 13:36:46 -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 25CCD206C0; Sun, 9 Aug 2020 17:36:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994605; bh=fqvCUxbPL0VuyK2/JldCW/ot+bbQbu5DhzCk451T4NY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QSnbAuNjZmkVhMqSSqpv/Td9WlYIWqeEYdhX4zMklm531AuPBNY1Oi5Q26OgXg2ZL zmQqsVqo23XwfnjMeAWOvMrJCkdjx+AdwNfsA1n19avZyBpOo79G1D6XiX4eIs6Vpo Qw4FAjIeidNURGl7Lc3OBKaoisNX9jSOoWHqxY2g= Date: Sun, 9 Aug 2020 18:36:41 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron , =?UTF-8?B?TcOlcnRlbg==?= Lindahl Subject: Re: [PATCH v3 21/27] iio:adc:ti-adc084s021 Fix alignment and data leak issues. Message-ID: <20200809183641.44a22a39@archlinux> In-Reply-To: <20200722155103.979802-22-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> <20200722155103.979802-22-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=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Wed, 22 Jul 2020 16:50:57 +0100 Jonathan Cameron wrote: > From: Jonathan Cameron >=20 > 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 an 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(). >=20 > This data is allocated with kzalloc so no data can leak apart from > previous readings. >=20 > The force alignment of ts is not strictly necessary in this case > but reduces the fragility of the code. >=20 > Fixes: 3691e5a69449 ("iio: adc: add driver for the ti-adc084s021 chip") > Reported-by: Lars-Peter Clausen > Cc: M=C3=A5rten Lindahl > Signed-off-by: Jonathan Cameron Applied and marked for stable. thanks, Jonathan > --- > drivers/iio/adc/ti-adc084s021.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) >=20 > diff --git a/drivers/iio/adc/ti-adc084s021.c b/drivers/iio/adc/ti-adc084s= 021.c > index 9017e1e24273..dfba34834a57 100644 > --- a/drivers/iio/adc/ti-adc084s021.c > +++ b/drivers/iio/adc/ti-adc084s021.c > @@ -26,6 +26,11 @@ struct adc084s021 { > struct spi_transfer spi_trans; > struct regulator *reg; > struct mutex lock; > + /* Buffer used to align data */ > + struct { > + __be16 channels[4]; > + s64 ts __aligned(8); > + } scan; > /* > * DMA (thus cache coherency maintenance) requires the > * transfer buffers to live in their own cache line. > @@ -141,14 +146,13 @@ static irqreturn_t adc084s021_buffer_trigger_handle= r(int irq, void *pollfunc) > struct iio_poll_func *pf =3D pollfunc; > struct iio_dev *indio_dev =3D pf->indio_dev; > struct adc084s021 *adc =3D iio_priv(indio_dev); > - __be16 data[8] =3D {0}; /* 4 * 16-bit words of data + 8 bytes timestamp= */ > =20 > mutex_lock(&adc->lock); > =20 > - if (adc084s021_adc_conversion(adc, &data) < 0) > + if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0) > dev_err(&adc->spi->dev, "Failed to read data\n"); > =20 > - iio_push_to_buffers_with_timestamp(indio_dev, data, > + iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, > iio_get_time_ns(indio_dev)); > mutex_unlock(&adc->lock); > iio_trigger_notify_done(indio_dev->trig);