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=-18.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D6075C1B087 for ; Sat, 5 Dec 2020 18:34:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC4DE22838 for ; Sat, 5 Dec 2020 18:34:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726330AbgLESef (ORCPT ); Sat, 5 Dec 2020 13:34:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:58726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726534AbgLESe2 (ORCPT ); Sat, 5 Dec 2020 13:34:28 -0500 Subject: patch "iio:light:rpr0521: Fix timestamp alignment and prevent data leak." added to staging-next DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1607183270; bh=DQmAEaLWfrnGNacTll+Sdl2jva7Cs5BUrRgQj5iyhkY=; h=To:From:Date:From; b=WnZhFpx5HdjKZPFU8mlXKc5+mfxjSvrHZh6gRrRkDpN2l7m9568NfVikZNWvDXHUO 2JFJ3zjzbCrLzP1uAwqXpS/rCJj3pb6DWMzZXhIvJjKvXGO28J0vpjvIkh6q0gUUeG CJqVkgFfceVmpG9izXjyXJukbfD1A9U6g2jhbaBw= To: Jonathan.Cameron@huawei.com, Stable@vger.kernel.org, alexandru.ardelean@analog.com, mikko.koivunen@fi.rohmeurope.com From: Date: Sat, 05 Dec 2020 16:46:00 +0100 Message-ID: <1607183160189@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled iio:light:rpr0521: Fix timestamp alignment and prevent data leak. to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-next branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will also be merged in the next major kernel release during the merge window. If you have any questions about this process, please let me know. >From a61817216bcc755eabbcb1cf281d84ccad267ed1 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Sun, 20 Sep 2020 12:27:35 +0100 Subject: iio:light:rpr0521: Fix timestamp alignment and prevent data leak. 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 and in this case the status byte from the device. The forced alignment of ts is not necessary in this case but it potentially makes the code less fragile. >>From personal communications with Mikko: We could probably split the reading of the int register, but it would mean a significant performance cost of 20 i2c clock cycles. Fixes: e12ffd241c00 ("iio: light: rpr0521 triggered buffer") Signed-off-by: Jonathan Cameron Reviewed-by: Alexandru Ardelean Cc: Mikko Koivunen Cc: Link: https://lore.kernel.org/r/20200920112742.170751-2-jic23@kernel.org --- drivers/iio/light/rpr0521.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/iio/light/rpr0521.c b/drivers/iio/light/rpr0521.c index aa2972b04833..31224a33bade 100644 --- a/drivers/iio/light/rpr0521.c +++ b/drivers/iio/light/rpr0521.c @@ -194,6 +194,17 @@ struct rpr0521_data { bool pxs_need_dis; struct regmap *regmap; + + /* + * Ensure correct naturally aligned timestamp. + * Note that the read will put garbage data into + * the padding but this should not be a problem + */ + struct { + __le16 channels[3]; + u8 garbage; + s64 ts __aligned(8); + } scan; }; static IIO_CONST_ATTR(in_intensity_scale_available, RPR0521_ALS_SCALE_AVAIL); @@ -449,8 +460,6 @@ static irqreturn_t rpr0521_trigger_consumer_handler(int irq, void *p) struct rpr0521_data *data = iio_priv(indio_dev); int err; - u8 buffer[16]; /* 3 16-bit channels + padding + ts */ - /* Use irq timestamp when reasonable. */ if (iio_trigger_using_own(indio_dev) && data->irq_timestamp) { pf->timestamp = data->irq_timestamp; @@ -461,11 +470,11 @@ static irqreturn_t rpr0521_trigger_consumer_handler(int irq, void *p) pf->timestamp = iio_get_time_ns(indio_dev); err = regmap_bulk_read(data->regmap, RPR0521_REG_PXS_DATA, - &buffer, + data->scan.channels, (3 * 2) + 1); /* 3 * 16-bit + (discarded) int clear reg. */ if (!err) iio_push_to_buffers_with_timestamp(indio_dev, - buffer, pf->timestamp); + &data->scan, pf->timestamp); else dev_err(&data->client->dev, "Trigger consumer can't read from sensor.\n"); -- 2.29.2