From patchwork Sun Jun 7 15:53:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11591675 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 E4175912 for ; Sun, 7 Jun 2020 15:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD983207C3 for ; Sun, 7 Jun 2020 15:56:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545386; bh=Qa0PTvT+TZfKmIYSONfUAPX9vxxkYEnSVb1RnyUP/Zg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yidlfnmdNaAVabedeUrndQHeIojaKGYENDn0BI8Oe64+/5LCZ7xFNPlm539n3NWpN 5Pcp9JlleMvAkqLHAyCVT36do5RLwl06mdXY7SiWDl7vMlLlsGeyThfBcoH3mrIvkc R9U+wH45Fp6BDEms9BRCvXbNEIe4h5pQzLsPOJio= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726692AbgFGP40 (ORCPT ); Sun, 7 Jun 2020 11:56:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:57304 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726631AbgFGP4Z (ORCPT ); Sun, 7 Jun 2020 11:56:25 -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 8BD3920774; Sun, 7 Jun 2020 15:56:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545385; bh=Qa0PTvT+TZfKmIYSONfUAPX9vxxkYEnSVb1RnyUP/Zg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vx1gqlpISGv5L9Nu/+OGQx/CE8/XDSf2gOmxt2q9qJz0rC+CY3Z5nVH9XEYZIIyOf Vb5jIfA6/qewa2FrxPdIhksPXOU8Y0FzEPYqOgLCHPiy2hafhooXKmjYK4TteJSbyB LY8Up1NuSDWnbqzkwVeos851I0UOp13ERFBLzeEk= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald-Stadler Subject: [PATCH 08/32] iio:light:si1145: Fix timestamp alignment and prevent data leak. Date: Sun, 7 Jun 2020 16:53:44 +0100 Message-Id: <20200607155408.958437-9-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 24 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 array in the iio_priv() data with alignment explicitly requested. This data is allocated with kzalloc so no data can leak appart from previous readings. Fixes: ac45e57f1590 ("iio: light: Add driver for Silabs si1132, si1141/2/3 and si1145/6/7 ambient light, uv index and proximity sensors") Reported-by: Lars-Peter Clausen Cc: Peter Meerwald-Stadler Signed-off-by: Jonathan Cameron --- drivers/iio/light/si1145.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iio/light/si1145.c b/drivers/iio/light/si1145.c index e1f989dd3a3d..16958160cf63 100644 --- a/drivers/iio/light/si1145.c +++ b/drivers/iio/light/si1145.c @@ -179,6 +179,8 @@ struct si1145_data { bool autonomous; struct iio_trigger *trig; int meas_rate; + /* Ensure timestamp will be naturally aligned if present */ + u8 buffer[24] __aligned(8); }; /** @@ -445,7 +447,6 @@ static irqreturn_t si1145_trigger_handler(int irq, void *private) * 6*2 bytes channels data + 4 bytes alignment + * 8 bytes timestamp */ - u8 buffer[24]; int i, j = 0; int ret; u8 irq_status = 0; @@ -478,7 +479,7 @@ static irqreturn_t si1145_trigger_handler(int irq, void *private) ret = i2c_smbus_read_i2c_block_data_or_emulated( data->client, indio_dev->channels[i].address, - sizeof(u16) * run, &buffer[j]); + sizeof(u16) * run, &data->buffer[j]); if (ret < 0) goto done; j += run * sizeof(u16); @@ -493,7 +494,7 @@ static irqreturn_t si1145_trigger_handler(int irq, void *private) goto done; } - iio_push_to_buffers_with_timestamp(indio_dev, buffer, + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, iio_get_time_ns(indio_dev)); done: