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=-12.7 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 E6A00C43461 for ; Tue, 15 Sep 2020 23:21:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A412F208E4 for ; Tue, 15 Sep 2020 23:21:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600212089; bh=oPnzkviW5RFXpkvip4Qi0MFpC8KohykpXyGJM8vAqeQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oPtGgcIcEgf3I562lEeGiVi8UnR+wNP5Yh6f+r2Mas7QBhuWA16vm9fDFup91oxg9 R07xgGw6wVfWNdSis/pGeJH63A+BaMUm7fvVj3YO8CZTr/iYxNsVNzfKVgk/OMrGkb 6D7B9JKu5gFACLD8qqF0nr5NCj0zEDCt4sWVetlY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727390AbgIOXVS (ORCPT ); Tue, 15 Sep 2020 19:21:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:48808 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727210AbgIOOiW (ORCPT ); Tue, 15 Sep 2020 10:38:22 -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 1BB36224B0; Tue, 15 Sep 2020 14:28:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180119; bh=oPnzkviW5RFXpkvip4Qi0MFpC8KohykpXyGJM8vAqeQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NKLVLJBVqNU7DPljzO050VuUL+VzZfR3OlbQMwf2qr5chWssqIp5gi7dVQLokHto9 uHn0iRp3KHpHxB4ZmPWiOAyv013NqUf/EkVLy5WM2EO/9A9RipAG/nllvoYJKSsJXl yxI2giacJMuZa89uTwvtBzXXzglzrrPFizUmDu7g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , =?UTF-8?q?M=C3=A5rten=20Lindahl?= , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 5.8 115/177] iio:adc:ti-adc084s021 Fix alignment and data leak issues. Date: Tue, 15 Sep 2020 16:13:06 +0200 Message-Id: <20200915140659.155360656@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140653.610388773@linuxfoundation.org> References: <20200915140653.610388773@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jonathan Cameron commit a661b571e3682705cb402a5cd1e970586a3ec00f 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 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(). This data is allocated with kzalloc so no data can leak apart from previous readings. The force alignment of ts is not strictly necessary in this case but reduces the fragility of the code. Fixes: 3691e5a69449 ("iio: adc: add driver for the ti-adc084s021 chip") Reported-by: Lars-Peter Clausen Cc: Mårten Lindahl Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/ti-adc084s021.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/iio/adc/ti-adc084s021.c +++ b/drivers/iio/adc/ti-adc084s021.c @@ -25,6 +25,11 @@ struct adc084s021 { struct spi_transfer spi_trans; struct regulator *reg; struct mutex lock; + /* Buffer used to align data */ + struct { + __be16 channels[4]; + s64 ts __aligned(8); + } scan; /* * DMA (thus cache coherency maintenance) requires the * transfer buffers to live in their own cache line. @@ -140,14 +145,13 @@ static irqreturn_t adc084s021_buffer_tri struct iio_poll_func *pf = pollfunc; struct iio_dev *indio_dev = pf->indio_dev; struct adc084s021 *adc = iio_priv(indio_dev); - __be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */ mutex_lock(&adc->lock); - if (adc084s021_adc_conversion(adc, &data) < 0) + if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0) dev_err(&adc->spi->dev, "Failed to read data\n"); - iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, iio_get_time_ns(indio_dev)); mutex_unlock(&adc->lock); iio_trigger_notify_done(indio_dev->trig);