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 48797C433E0 for ; Sun, 9 Aug 2020 17:39:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28AB3206CD for ; Sun, 9 Aug 2020 17:39:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994783; bh=tt9uCUay/V3Ne3luEQ0Gbf3EM1MjXCZLK/K9UQoM59U=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=jDmZd5IlkZAiCxrqPG+ON+50Dytip2cnqw61E7fs7pcKjJRJy1aOpV7xwLAdxlvSj FeDF5VUtnpDi0i9+uUawC3dsIQNGsYQGZ0vy26qPCyVdQndctw5YX9B1f8g3DtGC5l ktQSwrreIJFvUsdM8kh/oVEZqyMqK1Si8t3AxF7M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726236AbgHIRjm (ORCPT ); Sun, 9 Aug 2020 13:39:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:32998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726199AbgHIRjm (ORCPT ); Sun, 9 Aug 2020 13:39:42 -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 16256206C0; Sun, 9 Aug 2020 17:39:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596994782; bh=tt9uCUay/V3Ne3luEQ0Gbf3EM1MjXCZLK/K9UQoM59U=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=F8BYb0sDWkEmMXFyQdwqt4UAtIDzCxeqo+eKLuRJa1XFTGjBPCWTaFta4XQ/NTP9M N2JF+EwHxYwQ4Xt2a93xc+GBfq5hHQ3kJAI9FirnksIZVYQlOPM4jtufk3C3xzKBLs in0oSDo9rRYlLlkwUKMJpiYD7/SQriL64Q8CBT6w= Date: Sun, 9 Aug 2020 18:39:38 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron , Akinobu Mita Subject: Re: [PATCH v3 27/27] iio:adc:max1118 Fix alignment of timestamp and data leak issues Message-ID: <20200809183938.0f29d680@archlinux> In-Reply-To: <20200722155103.979802-28-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> <20200722155103.979802-28-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 16:51:03 +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() data. > > This data is allocated with kzalloc so no data can leak apart > from previous readings. > > The explicit alignment of ts is necessary to ensure correct padding > on architectures where s64 is only 4 bytes aligned such as x86_32. > > Fixes: a9e9c7153e96 ("iio: adc: add max1117/max1118/max1119 ADC driver") > Reported-by: Lars-Peter Clausen > Cc: Akinobu Mita > Signed-off-by: Jonathan Cameron Applied and marked for stable. Thanks, Jonathan > --- > drivers/iio/adc/max1118.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/max1118.c b/drivers/iio/adc/max1118.c > index 01b20e420ac4..6efb0b43d938 100644 > --- a/drivers/iio/adc/max1118.c > +++ b/drivers/iio/adc/max1118.c > @@ -36,6 +36,11 @@ struct max1118 { > struct spi_device *spi; > struct mutex lock; > struct regulator *reg; > + /* Ensure natural alignment of buffer elements */ > + struct { > + u8 channels[2]; > + s64 ts __aligned(8); > + } scan; > > u8 data ____cacheline_aligned; > }; > @@ -166,7 +171,6 @@ static irqreturn_t max1118_trigger_handler(int irq, void *p) > struct iio_poll_func *pf = p; > struct iio_dev *indio_dev = pf->indio_dev; > struct max1118 *adc = iio_priv(indio_dev); > - u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ > int scan_index; > int i = 0; > > @@ -184,10 +188,10 @@ static irqreturn_t max1118_trigger_handler(int irq, void *p) > goto out; > } > > - data[i] = ret; > + adc->scan.channels[i] = ret; > i++; > } > - 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)); > out: > mutex_unlock(&adc->lock);