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 4D5EFC433E0 for ; Sun, 9 Aug 2020 17:34:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CF26206CD for ; Sun, 9 Aug 2020 17:34:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994490; bh=KTEt82N9f2jzG6+h0qF0Lkw+0MYoxoDF1V+dk9uXIqs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=RMsuVYR5IqWubbzAtIBCAhKd77R02Nls0zhO/MrGwlG8Fx/P+uYOXffEtNApmH8gH ddwWQaKgQepQftKJZj3WG5NEvqk+rTnFiK1pErDy94op5jxlx13wqv1mbNNvecooWA iq9R9I0YKzui83uV8osA92CSrjnttYB9c7bIpe9I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726236AbgHIRet (ORCPT ); Sun, 9 Aug 2020 13:34:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:59486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726229AbgHIRet (ORCPT ); Sun, 9 Aug 2020 13:34:49 -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 27FEF2065D; Sun, 9 Aug 2020 17:34:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994489; bh=KTEt82N9f2jzG6+h0qF0Lkw+0MYoxoDF1V+dk9uXIqs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uE7bsbZNEP9DJsbuUgXhhDMX7Z/fPhJKoj0kqJGO7nbP2CEjCAOsSzLp4PSIqgkoV Xjpsiyk1ZE63ItZ7A35sgMV+SVBEY55DEox91eqq9E8glZdspjBPfz3LIq+nr0KaKM 3mbmqKmvYLNhZFSIYIEZ9m9Cq0wtu0woUpR6HRBI= Date: Sun, 9 Aug 2020 18:34:45 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron Subject: Re: [PATCH v3 20/27] iio:adc:ti-adc081c Fix alignment and data leak issues Message-ID: <20200809183445.4a9fad59@archlinux> In-Reply-To: <20200722155103.979802-21-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> <20200722155103.979802-21-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 16:50:56 +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 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(). > > This data is allocated with kzalloc so no data can leak apart > from previous readings. > > The eplicit alignment of ts is necessary to ensure correct padding > on x86_32 where s64 is only aligned to 4 bytes. > > Fixes: 08e05d1fce5c (" ti-adc081c: Initial triggered buffer support") > Reported-by: Lars-Peter Clausen > Signed-off-by: Jonathan Cameron Applied and marked for stable. Thanks, Jonathan > --- > drivers/iio/adc/ti-adc081c.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/ti-adc081c.c b/drivers/iio/adc/ti-adc081c.c > index 9426f70a8005..cf63983a54d9 100644 > --- a/drivers/iio/adc/ti-adc081c.c > +++ b/drivers/iio/adc/ti-adc081c.c > @@ -33,6 +33,12 @@ struct adc081c { > > /* 8, 10 or 12 */ > int bits; > + > + /* Ensure natural alignment of buffer elements */ > + struct { > + u16 channel; > + s64 ts __aligned(8); > + } scan; > }; > > #define REG_CONV_RES 0x00 > @@ -128,14 +134,13 @@ static irqreturn_t adc081c_trigger_handler(int irq, void *p) > struct iio_poll_func *pf = p; > struct iio_dev *indio_dev = pf->indio_dev; > struct adc081c *data = iio_priv(indio_dev); > - u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */ > int ret; > > ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES); > if (ret < 0) > goto out; > - buf[0] = ret; > - iio_push_to_buffers_with_timestamp(indio_dev, buf, > + data->scan.channel = ret; > + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, > iio_get_time_ns(indio_dev)); > out: > iio_trigger_notify_done(indio_dev->trig);