From patchwork Tue Nov 3 20:37:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 316984 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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D6AF0C2D0A3 for ; Tue, 3 Nov 2020 21:20:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D431206DC for ; Tue, 3 Nov 2020 21:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604438444; bh=XiOVlSx8Y8OV3R6NNOf+x3pi9FwzEiFGpXqenKISlFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=knYSx/n4kqQBN6BmDY4WdekgxgRDUrCXrN4NKRC53yEaYRs15+z0sZy8CJk8lUjnV rFuVEhf9pIjJwAyLbvjxVTdS9uk3J9cXOzbv70J5ICLkIhwMhWx0GJTcp+N950E1hT kFrc8V0N8EnCE8SpRFEYMlNWdYfsQL25p9Zwp58M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388034AbgKCVGw (ORCPT ); Tue, 3 Nov 2020 16:06:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:45910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388221AbgKCVGv (ORCPT ); Tue, 3 Nov 2020 16:06:51 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 41B0B206B5; Tue, 3 Nov 2020 21:06:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437610; bh=XiOVlSx8Y8OV3R6NNOf+x3pi9FwzEiFGpXqenKISlFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TmrRdwTnkGV2f6Aq9LgT19qDgwBxTmFMldSCJEniTCAVEhXgU1lXHi1h3AZ1/bKKr +KpthjPuPdS9GcHavXjdo2YlRPhbiKpjYe/4e0FrWAkYQwn4Tsr62/D/JlBgjX82Fi BI5ZYdSx+qlhODAsSmrk7Z7r5r1EK21bwMmSC8+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Andy Shevchenko , Akinobu Mita , Stable@vger.kernel.org Subject: [PATCH 4.19 150/191] iio:adc:ti-adc0832 Fix alignment issue with timestamp Date: Tue, 3 Nov 2020 21:37:22 +0100 Message-Id: <20201103203246.727251082@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203232.656475008@linuxfoundation.org> References: <20201103203232.656475008@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit 39e91f3be4cba51c1560bcda3a343ed1f64dc916 upstream. 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. We fix this 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 apart from previous readings. Note that previously no data could leak 'including' previous readings but I don't think it is an issue to potentially leak them like this now does. In this case the postioning of the timestamp is depends on what other channels are enabled. As such we cannot use a structure to make the alignment explicit as it would be missleading by suggesting only one possible location for the timestamp. Fixes: 815bbc87462a ("iio: ti-adc0832: add triggered buffer support") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Akinobu Mita Cc: Link: https://lore.kernel.org/r/20200722155103.979802-25-jic23@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/ti-adc0832.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/iio/adc/ti-adc0832.c +++ b/drivers/iio/adc/ti-adc0832.c @@ -31,6 +31,12 @@ struct adc0832 { struct regulator *reg; struct mutex lock; u8 mux_bits; + /* + * Max size needed: 16x 1 byte ADC data + 8 bytes timestamp + * May be shorter if not all channels are enabled subject + * to the timestamp remaining 8 byte aligned. + */ + u8 data[24] __aligned(8); u8 tx_buf[2] ____cacheline_aligned; u8 rx_buf[2]; @@ -202,7 +208,6 @@ static irqreturn_t adc0832_trigger_handl struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct adc0832 *adc = iio_priv(indio_dev); - u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */ int scan_index; int i = 0; @@ -220,10 +225,10 @@ static irqreturn_t adc0832_trigger_handl goto out; } - data[i] = ret; + adc->data[i] = ret; i++; } - iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_push_to_buffers_with_timestamp(indio_dev, adc->data, iio_get_time_ns(indio_dev)); out: mutex_unlock(&adc->lock);