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=-10.1 required=3.0 tests=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=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 55B4DC433E0 for ; Mon, 25 May 2020 17:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 32AF620878 for ; Mon, 25 May 2020 17:09:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590426550; bh=2ZongO4r61nzcvxv3gVNk8l5fF2nHAYt8WrvrUHK6PI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UXkDmutwIZyNC36IRaJj+k4tfUq2vRx98XXORbe1O1Y/jT18O/e53AX4tw8kkomfz mBQiM4JkzwHd8wgwCdfjHcOvYzNeRCOjmFzBCl6HcvSQQjndm9oC3x6W4n67iY/t0P 3/6FUTn2oDetjjq1mRjC20dd3vVR/6yDXCiaNPp0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391275AbgEYRJJ (ORCPT ); Mon, 25 May 2020 13:09:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:42602 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388812AbgEYRJJ (ORCPT ); Mon, 25 May 2020 13:09:09 -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 A98532078B; Mon, 25 May 2020 17:09:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590426548; bh=2ZongO4r61nzcvxv3gVNk8l5fF2nHAYt8WrvrUHK6PI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tfW3fbN59Y81bT2okCVlNyvD44wESrnqEnmbu/fCvGkdUFLKCI0m1uNkMDwIEOZW0 L6K8oB6xH9eBPeOGhP9/fAbh2MtE1+6e9U4E07H8mTn+zqcZadviZTK41UlA8Yga5Q 8zalC3Z6s25Iqzy40MQ2p/i+teRjuqHGzGUWHD90= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Jonathan Cameron , Lars-Peter Clausen , Gregor Boirie , Andy Shevchenko , Linus Walleij Subject: [PATCH 07/25] iio:magnetometer:ak8975 Fix alignment and data leak issues. Date: Mon, 25 May 2020 18:06:10 +0100 Message-Id: <20200525170628.503283-8-jic23@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200525170628.503283-1-jic23@kernel.org> References: <20200525170628.503283-1-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 structure in the iio_priv() data. This data is allocated with kzalloc so no data can leak apart from previous readings. Fixes: bc11ca4a0b84 ("iio:magnetometer:ak8975: triggered buffer support") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Cc: Gregor Boirie Cc: Andy Shevchenko Cc: Linus Walleij --- drivers/iio/magnetometer/ak8975.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c index 3c881541ae72..673ac70d014d 100644 --- a/drivers/iio/magnetometer/ak8975.c +++ b/drivers/iio/magnetometer/ak8975.c @@ -365,6 +365,12 @@ struct ak8975_data { struct iio_mount_matrix orientation; struct regulator *vdd; struct regulator *vid; + + /* Ensure natural alignment of timestamp */ + struct { + s16 channels[3]; + s64 ts; + } scan; }; /* Enable attached power regulator if any. */ @@ -787,7 +793,6 @@ static void ak8975_fill_buffer(struct iio_dev *indio_dev) const struct i2c_client *client = data->client; const struct ak_def *def = data->def; int ret; - s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */ __le16 fval[3]; mutex_lock(&data->lock); @@ -810,11 +815,14 @@ static void ak8975_fill_buffer(struct iio_dev *indio_dev) mutex_unlock(&data->lock); /* Clamp to valid range. */ - buff[0] = clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range); - buff[1] = clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range); - buff[2] = clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range); - - iio_push_to_buffers_with_timestamp(indio_dev, buff, + data->scan.channels[0] = + clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range); + data->scan.channels[1] = + clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range); + data->scan.channels[2] = + clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range); + + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); return; -- 2.26.2