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=ham 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 5A273C433E2 for ; Tue, 15 Sep 2020 14:30:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1748922A84 for ; Tue, 15 Sep 2020 14:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180247; bh=oPnzkviW5RFXpkvip4Qi0MFpC8KohykpXyGJM8vAqeQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=U8fU/yNFwLAWnz931NhK5qy8nF7T0KdkyqFdRfkrwGFeEXII9ktHou2J3uMJMJaAN yPtTNbOc7G4heyN0JO5wlM2Arz+CGwCEnw1+K40fYLbJCShoHs8bh2UCYJ8MQW+BPI t6ak+hs/Wwicif557uqmyrFbGcgaVa0vBBj1qvs8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727020AbgIOOa0 (ORCPT ); Tue, 15 Sep 2020 10:30:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:43012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbgIOO3B (ORCPT ); Tue, 15 Sep 2020 10:29:01 -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 4D2FB22A85; Tue, 15 Sep 2020 14:21:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179691; bh=oPnzkviW5RFXpkvip4Qi0MFpC8KohykpXyGJM8vAqeQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c+ttdepg8aMz0wTG8SFSAby9f6UidHsYkZ2NKw0Ut56P5VTzXh6QHZkMKeyCMtgD/ T3iyHKW0hndHqNw4LpUlODGlrUIq1v/c7sE+hYT2fZQw8sNnj6YJExvJYlu1M1sxFp OI+1eVREMyGhyc1ku5wRdtSSNAepiZyO+AJ2agtY= 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 5.4 080/132] iio:adc:ti-adc084s021 Fix alignment and data leak issues. Date: Tue, 15 Sep 2020 16:13:02 +0200 Message-Id: <20200915140648.104960116@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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);