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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 38A8BC43468 for ; Mon, 21 Sep 2020 16:38:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 007E9206DC for ; Mon, 21 Sep 2020 16:38:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706307; bh=QtLLmG3kh0dT55OUon/4hi34yStQhL40NliPqaR7GU4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Horyt8yJ5B3I89DEoIWLuN605PRIp0wslK4xK9NIIyZNvdfHz+Y+lb29gklHaPg2u V9SUmaEm8+I62w7+OW+KrxCjQ4i/ah71ITcZfqZMS/KjlKh1uUlCDHv3bI4RfANy9J eLw/c99gaI9NdLQM4OxJ7xJUVOTA69wX2IxRAqX8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728432AbgIUQiH (ORCPT ); Mon, 21 Sep 2020 12:38:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:38810 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728766AbgIUQh5 (ORCPT ); Mon, 21 Sep 2020 12:37:57 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5E47C206DC; Mon, 21 Sep 2020 16:37:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706277; bh=QtLLmG3kh0dT55OUon/4hi34yStQhL40NliPqaR7GU4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XGUGHUEJJ30CxlhH/c4Ha6RFJ7cowCSFcVLdV5VV82j98KGaxwRC0bmRTfLhElu7x 8crn6r9FxvkPtIJY2HrK7Guiy2RVj3wOFeydLJ7aPzYk9o+VdpkqLZ6Rn2Xnka7e8b bZC3lwLjh24umsh0G8EnqpGXpByID4m1wuf2M0a8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Stable@vger.kernel.org, Andy Shevchenko Subject: [PATCH 4.14 36/94] iio:accel:mma7455: Fix timestamp alignment and prevent data leak. Date: Mon, 21 Sep 2020 18:27:23 +0200 Message-Id: <20200921162037.207424110@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jonathan Cameron commit 7e5ac1f2206eda414f90c698fe1820dee873394d upstream. 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 16 byte u8 array 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 ensured by use of an explicit c structure. This data is allocated with kzalloc so no data can leak appart from previous readings. The force alignment of ts is not strictly necessary in this particularly case but does make the code less fragile. Fixes: a84ef0d181d9 ("iio: accel: add Freescale MMA7455L/MMA7456L 3-axis accelerometer driver") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Cc: Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/iio/accel/mma7455_core.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/drivers/iio/accel/mma7455_core.c +++ b/drivers/iio/accel/mma7455_core.c @@ -55,6 +55,14 @@ struct mma7455_data { struct regmap *regmap; + /* + * Used to reorganize data. Will ensure correct alignment of + * the timestamp if present + */ + struct { + __le16 channels[3]; + s64 ts __aligned(8); + } scan; }; static int mma7455_drdy(struct mma7455_data *mma7455) @@ -85,19 +93,19 @@ static irqreturn_t mma7455_trigger_handl struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct mma7455_data *mma7455 = iio_priv(indio_dev); - u8 buf[16]; /* 3 x 16-bit channels + padding + ts */ int ret; ret = mma7455_drdy(mma7455); if (ret) goto done; - ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf, - sizeof(__le16) * 3); + ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, + mma7455->scan.channels, + sizeof(mma7455->scan.channels)); if (ret) goto done; - iio_push_to_buffers_with_timestamp(indio_dev, buf, + iio_push_to_buffers_with_timestamp(indio_dev, &mma7455->scan, iio_get_time_ns(indio_dev)); done: