From patchwork Sun Jun 7 15:53:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11591691 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 9E7D9913 for ; Sun, 7 Jun 2020 15:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86D0B2076A for ; Sun, 7 Jun 2020 15:56:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545397; bh=HP6QiGsO6mZHJotBLGSvYQhGJVexxnVRqWQ+bd20rzA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YQbXX98oyrxfIhruWmtgW72GZSSGlfIVXfypoNimR7SKiPQZar0cHp/YXTVtDMbTO VdsfBfNEEi93ki4J9PSTWt5XvyHXV8uF8CGLBHqVPvJ2Ms7DOd/lJCXhpDmk8tFOAB ANC2e/y9dPmfYzcuVics+dDz4++J10+sxRsrD1mU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726732AbgFGP4h (ORCPT ); Sun, 7 Jun 2020 11:56:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:57466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726703AbgFGP4g (ORCPT ); Sun, 7 Jun 2020 11:56:36 -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 338402075A; Sun, 7 Jun 2020 15:56:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545396; bh=HP6QiGsO6mZHJotBLGSvYQhGJVexxnVRqWQ+bd20rzA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c7r+EwMLudIA5OV3n3KetK2rQ7qX3EBA4snowR3rNK8dqXdvqjmQff2xB+Obcqo7B 8uqcScypEGV4BRlJfuxMifEJ9vxXfYSd5pyeAaAi3II43w82DEzOqRg/Z2s/ObduRQ qjulse46bEXBFmPRFBVm8B7xMCx8UZh2hJ9R2k8c= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , Matt Ranostay , Alison Schofield Subject: [PATCH 16/32] iio:humidity:hdc100x Fix alignment and data leak issues Date: Sun, 7 Jun 2020 16:53:52 +0100 Message-Id: <20200607155408.958437-17-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. Fixes: 16bf793f86b2 ("iio: humidity: hdc100x: add triggered buffer support for HDC100X") Reported-by: Lars-Peter Clausen Acked-by: Matt Ranostay Cc: Alison Schofield Signed-off-by: Jonathan Cameron --- drivers/iio/humidity/hdc100x.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c index 3331141734c8..e64af35f5f6f 100644 --- a/drivers/iio/humidity/hdc100x.c +++ b/drivers/iio/humidity/hdc100x.c @@ -38,6 +38,11 @@ struct hdc100x_data { /* integration time of the sensor */ int adc_int_us[2]; + /* Ensure natural alignment of timestamp */ + struct { + __be16 channels[2]; + s64 ts __aligned(8); + } scan; }; /* integration time in us */ @@ -322,7 +327,6 @@ static irqreturn_t hdc100x_trigger_handler(int irq, void *p) struct i2c_client *client = data->client; int delay = data->adc_int_us[0] + data->adc_int_us[1]; int ret; - s16 buf[8]; /* 2x s16 + padding + 8 byte timestamp */ /* dual read starts at temp register */ mutex_lock(&data->lock); @@ -333,13 +337,13 @@ static irqreturn_t hdc100x_trigger_handler(int irq, void *p) } usleep_range(delay, delay + 1000); - ret = i2c_master_recv(client, (u8 *)buf, 4); + ret = i2c_master_recv(client, (u8 *)data->scan.channels, 4); if (ret < 0) { dev_err(&client->dev, "cannot read sensor data\n"); goto err; } - iio_push_to_buffers_with_timestamp(indio_dev, buf, + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); err: mutex_unlock(&data->lock);