From patchwork Sun Jun 7 15:54:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11591721 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 687B9912 for ; Sun, 7 Jun 2020 15:56:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51EAF207F9 for ; Sun, 7 Jun 2020 15:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545418; bh=du8yk3rKsbhTwjnvXwqDzbgB7MW9kseCaTDwmJK04LA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QF3/IpRN+L5bZXtTJ/cnkRA9XLV8BCq3gwoR/ka/4vDG7DiZA4GaLY1HOKL3darYH SE9/U9c8JIiOPUVCuuW0cZqDrk/AsSSQ2T68CLzygnlMGoQ71EW5ECDy7EtWXBK59i ipf5Z6e5ytUD+ThX3C4AN2uV1cqTGWvaTkA+zAU4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726823AbgFGP45 (ORCPT ); Sun, 7 Jun 2020 11:56:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:57700 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726703AbgFGP45 (ORCPT ); Sun, 7 Jun 2020 11:56:57 -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 7E2642076A; Sun, 7 Jun 2020 15:56:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545416; bh=du8yk3rKsbhTwjnvXwqDzbgB7MW9kseCaTDwmJK04LA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gyt8kpLbBDN3S9xZe4r05e0+O2ujVNNpvWHEGJZU3ycXW+5gxGSJgiZupoG6ytuES Vynp56sPlRQZSkhOL5AwJrB6MN4uwrbiZp9ExQtW5TYdPboS0qYp4hJAmWqdSVkBPR UE2z/XewUlr0aAkRpYgISp0+arBnXEEW2DrJuVEs= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , =?utf-8?q?Stefan_Br=C3=BCns?= , Marc Titinger Subject: [PATCH 31/32] iio:adc:ina2xx Fix timestamp alignment issue. Date: Sun, 7 Jun 2020 16:54:07 +0100 Message-Id: <20200607155408.958437-32-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 a 32 byte 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 with alignment explicitly requested. This data is allocated with kzalloc so no data can leak apart from previous readings. If we want this in older stables will need manual backport due to driver reworks. Fixes: c43a102e67db ("iio: ina2xx: add support for TI INA2xx Power Monitors") Reported-by: Lars-Peter Clausen Cc: Stefan Brüns Cc: Marc Titinger Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ina2xx-adc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c index 467f48b6f451..6f466d42c520 100644 --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -146,6 +146,8 @@ struct ina2xx_chip_info { int range_vbus; /* Bus voltage maximum in V */ int pga_gain_vshunt; /* Shunt voltage PGA gain */ bool allow_async_readout; + /* data buffer needs space for channel data and timestap */ + unsigned short data[4 + sizeof(s64)/sizeof(short)] __aligned(8); }; static const struct ina2xx_config ina2xx_config[] = { @@ -738,8 +740,6 @@ static int ina2xx_conversion_ready(struct iio_dev *indio_dev) static int ina2xx_work_buffer(struct iio_dev *indio_dev) { struct ina2xx_chip_info *chip = iio_priv(indio_dev); - /* data buffer needs space for channel data and timestap */ - unsigned short data[4 + sizeof(s64)/sizeof(short)]; int bit, ret, i = 0; s64 time; @@ -758,10 +758,10 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev) if (ret < 0) return ret; - data[i++] = val; + chip->data[i++] = val; } - iio_push_to_buffers_with_timestamp(indio_dev, data, time); + iio_push_to_buffers_with_timestamp(indio_dev, chip->data, time); return 0; };