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 4879FC4345A for ; Wed, 22 Jul 2020 15:53:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21CAE22BEF for ; Wed, 22 Jul 2020 15:53:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433229; bh=dkvt+oaphgkTDUnzSW8KJtLMYyCSAN74BaQkzRu7QWc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dknuRIoYKZMVQZEpXdb4A3GISXZc9+anKljfs5F0MBsQQ+ECI3/WdD4/5jHDaaK5p 6UXwo3TDzB8CBmFOQiRmkoXfJGFIe28fEFgV5/0nx5t2e1xIJThNL1Zs0D2Zf4lsVZ oBLMxdWQcSPxQ6PfZVkk3Df2Mikiy9Ei5AWu6cFo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732726AbgGVPxs (ORCPT ); Wed, 22 Jul 2020 11:53:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:35928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732624AbgGVPxs (ORCPT ); Wed, 22 Jul 2020 11:53:48 -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 CCF5320717; Wed, 22 Jul 2020 15:53:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433228; bh=dkvt+oaphgkTDUnzSW8KJtLMYyCSAN74BaQkzRu7QWc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m5T7Sps7jm+JVRfwvn7PtYKDI9gSbAT2mb9e+LA+OFTop2O/C/sU2hRwFLxcjCud3 ePxJSkDUOCUzVH9MpsebHL9j4UJTrNU9dYGVXUhIlhrpBnBe8lcbd7k/LbfTL5vE03 brIiem1If4E2r6jXExr+5bKcQEsWnr1Rl9uwkXY0= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron , =?UTF-8?q?Stefan=20Br=C3=BCns?= , Marc Titinger Subject: [PATCH v3 26/27] iio:adc:ina2xx Fix timestamp alignment issue. Date: Wed, 22 Jul 2020 16:51:02 +0100 Message-Id: <20200722155103.979802-27-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-Type: text/plain; charset=UTF-8 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 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. The explicit alignment isn't technically needed here, but it reduced fragility and avoids cut and paste into drivers where it will be needed. 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 | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c index 5ed63e874292..b573ec60a8b8 100644 --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -146,6 +146,11 @@ 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 timestamp */ + struct { + u16 chan[4]; + u64 ts __aligned(8); + } scan; }; static const struct ina2xx_config ina2xx_config[] = { @@ -738,8 +743,6 @@ 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 +761,10 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev) if (ret < 0) return ret; - data[i++] = val; + chip->scan.chan[i++] = val; } - iio_push_to_buffers_with_timestamp(indio_dev, data, time); + iio_push_to_buffers_with_timestamp(indio_dev, &chip->scan, time); return 0; }; -- 2.27.0