From patchwork Sun Jun 7 15:53:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11591693 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 097E7912 for ; Sun, 7 Jun 2020 15:56:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E758B2077D for ; Sun, 7 Jun 2020 15:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545398; bh=S2Jjnh0+tYrXK47pf9FbMkiy83Yzn3uSRUjW1h+pqAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=p0XlozrakltLEL7YMCu87Bj4bCOgjTuo7wiSUEmDJ8VBQ1fwl4lhH3SUQzywUlyfG dhaL8YWt18FPFZ2EHLPGexgUvx+fJQfrGc0nRRaclCm7/u7rkD5nqUZC9FDjF3UIes 3BprODiJQvsE+XYnJ2WHfQgol/Ubg9HTQ++reptQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726738AbgFGP4i (ORCPT ); Sun, 7 Jun 2020 11:56:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:57486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726703AbgFGP4h (ORCPT ); Sun, 7 Jun 2020 11:56:37 -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 B506C20659; Sun, 7 Jun 2020 15:56:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545397; bh=S2Jjnh0+tYrXK47pf9FbMkiy83Yzn3uSRUjW1h+pqAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ze/nVNAwCfjpYsMGM7EnMAupXeEl0qJGKyI2S8myoovk+cOLGcLR0GE6qV4d5fAjb 2JbCCuQ+nfUMkZhVfkXAP+SXNm2EKBYPAc9WA+P7sRVjtXCoHgv0B4OFVsF8u1Vs5U 277CUWr0kGMNyVAMuzLVLtUixyWWw9nOZaO6MGWA= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , Lorenzo Bianconi Subject: [PATCH 17/32] iio:humidity:hts221 Fix alignment and data leak issues Date: Sun, 7 Jun 2020 16:53:53 +0100 Message-Id: <20200607155408.958437-18-jic23@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200607155408.958437-1-jic23@kernel.org> References: <20200607155408.958437-1-jic23@kernel.org> MIME-Version: 1.0 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. Explicit alignment of ts needed to ensure consistent padding on all architectures (particularly x86_32 with it's 4 byte alignment of s64) Fixes: e4a70e3e7d84 ("iio: humidity: add support to hts221 rh/temp combo device") Reported-by: Lars-Peter Clausen Acked-by: Lorenzo Bianconi Signed-off-by: Jonathan Cameron --- drivers/iio/humidity/hts221.h | 7 +++++-- drivers/iio/humidity/hts221_buffer.c | 9 +++++---- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/iio/humidity/hts221.h b/drivers/iio/humidity/hts221.h index 7c650df77556..721359e226cb 100644 --- a/drivers/iio/humidity/hts221.h +++ b/drivers/iio/humidity/hts221.h @@ -14,8 +14,6 @@ #include -#define HTS221_DATA_SIZE 2 - enum hts221_sensor_type { HTS221_SENSOR_H, HTS221_SENSOR_T, @@ -39,6 +37,11 @@ struct hts221_hw { bool enabled; u8 odr; + /* Ensure natural alignment of timestamp */ + struct { + __le16 channels[2]; + s64 ts __aligned(8); + } scan; }; extern const struct dev_pm_ops hts221_pm_ops; diff --git a/drivers/iio/humidity/hts221_buffer.c b/drivers/iio/humidity/hts221_buffer.c index 21c6c160462d..59ede9860185 100644 --- a/drivers/iio/humidity/hts221_buffer.c +++ b/drivers/iio/humidity/hts221_buffer.c @@ -160,7 +160,6 @@ static const struct iio_buffer_setup_ops hts221_buffer_ops = { static irqreturn_t hts221_buffer_handler_thread(int irq, void *p) { - u8 buffer[ALIGN(2 * HTS221_DATA_SIZE, sizeof(s64)) + sizeof(s64)]; struct iio_poll_func *pf = p; struct iio_dev *iio_dev = pf->indio_dev; struct hts221_hw *hw = iio_priv(iio_dev); @@ -170,18 +169,20 @@ static irqreturn_t hts221_buffer_handler_thread(int irq, void *p) /* humidity data */ ch = &iio_dev->channels[HTS221_SENSOR_H]; err = regmap_bulk_read(hw->regmap, ch->address, - buffer, HTS221_DATA_SIZE); + &hw->scan.channels[0], + sizeof(hw->scan.channels[0])); if (err < 0) goto out; /* temperature data */ ch = &iio_dev->channels[HTS221_SENSOR_T]; err = regmap_bulk_read(hw->regmap, ch->address, - buffer + HTS221_DATA_SIZE, HTS221_DATA_SIZE); + &hw->scan.channels[1], + sizeof(hw->scan.channels[1])); if (err < 0) goto out; - iio_push_to_buffers_with_timestamp(iio_dev, buffer, + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, iio_get_time_ns(iio_dev)); out: