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=-13.1 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_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 2A796C433F4 for ; Wed, 22 Jul 2020 15:53:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00DA120717 for ; Wed, 22 Jul 2020 15:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433213; bh=bU/B4ZHBPu2q5zoajXKveNEYO5LK3+e8NB0+jBTWcak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2R/QuT9ffmE10mnGLdjobxMDGn4W5Lwmg2IrkxyXpurmevN6+QVevJzPgnHrEeiHj xaSfj8I1BBNKqVVHH0Inq702N776BZkbd9P9VUs+dfgwhxjg5BRPKfeonp5wRviglM OBGBwDOscnwxGfa+Q3DamvwVJVd2dXhmqwBjP/W0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729178AbgGVPxc (ORCPT ); Wed, 22 Jul 2020 11:53:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:35734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726427AbgGVPxb (ORCPT ); Wed, 22 Jul 2020 11:53:31 -0400 Received: from localhost.localdomain (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0019E2080D; Wed, 22 Jul 2020 15:53:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433211; bh=bU/B4ZHBPu2q5zoajXKveNEYO5LK3+e8NB0+jBTWcak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y6BcVgGpPAeIUZ/oxXM+kS0H6Qqumluva5gkJsAN1lHAEHuadAas8pdGL0pU4ycV/ 9HpHLVsbQ4LlzcjWuKi2cPA/5/r6cdzk2+Rq/4A/cL98MJbqvunpl5VH1s23bn2dcp NE2pzHSLY6LO5h9qC3juevCcwUSyggz+7gMB4W9Y= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron , Daniel Baluta Subject: [PATCH v3 15/27] iio:imu:bmi160 Fix alignment and data leak issues Date: Wed, 22 Jul 2020 16:50:51 +0100 Message-Id: <20200722155103.979802-16-jic23@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200722155103.979802-1-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org 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 array in the iio_priv() data with alignment explicitly requested. This data is allocated with kzalloc so no data can leak apart from previous readings. In this driver, depending on which channels are enabled, the timestamp can be in a number of locations. Hence we cannot use a structure to specify the datalayout without it being missleading. Fixes: 77c4ad2d6a9b ("iio: imu: Add initial support for Bosch BMI160") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Cc: Daniel Baluta Signed-off-by: Jonathan Cameron --- drivers/iio/imu/bmi160/bmi160.h | 2 ++ drivers/iio/imu/bmi160/bmi160_core.c | 5 ++--- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iio/imu/bmi160/bmi160.h b/drivers/iio/imu/bmi160/bmi160.h index a82e040bd109..d29f1b5d1658 100644 --- a/drivers/iio/imu/bmi160/bmi160.h +++ b/drivers/iio/imu/bmi160/bmi160.h @@ -10,6 +10,8 @@ struct bmi160_data { struct iio_trigger *trig; struct regulator_bulk_data supplies[2]; struct iio_mount_matrix orientation; + /* Ensure natural alignment for timestamp if present */ + __le16 buf[16] __aligned(8); }; extern const struct regmap_config bmi160_regmap_config; diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi160/bmi160_core.c index 222ebb26f013..86cfd75ea125 100644 --- a/drivers/iio/imu/bmi160/bmi160_core.c +++ b/drivers/iio/imu/bmi160/bmi160_core.c @@ -427,7 +427,6 @@ static irqreturn_t bmi160_trigger_handler(int irq, void *p) struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct bmi160_data *data = iio_priv(indio_dev); - __le16 buf[16]; /* 3 sens x 3 axis x __le16 + 3 x __le16 pad + 4 x __le16 tstamp */ int i, ret, j = 0, base = BMI160_REG_DATA_MAGN_XOUT_L; __le16 sample; @@ -438,10 +437,10 @@ static irqreturn_t bmi160_trigger_handler(int irq, void *p) &sample, sizeof(sample)); if (ret) goto done; - buf[j++] = sample; + data->buf[j++] = sample; } - iio_push_to_buffers_with_timestamp(indio_dev, buf, pf->timestamp); + iio_push_to_buffers_with_timestamp(indio_dev, data->buf, pf->timestamp); done: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; -- 2.27.0