From patchwork Mon Sep 21 16:27:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 263721 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 E4661C43468 for ; Mon, 21 Sep 2020 16:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA36623998 for ; Mon, 21 Sep 2020 16:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706346; bh=xWfbtvQi6jRbi8I/P0rqnE1igmz3Uiqjn4b6VweDl4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fK60KnUILbW5EVTznlu854IDMIBVciCKhpU1sjcEN8kv/ZbNSPYgy2lpCmyLF4ZmS SYf3tdCDGvTdY08PEJH8Qi+br3s3/rJ/R78+8ZcRMyj4ns6MuABctcs5eLeQn1k7ko CvU/ad+KYWTwo5lHrTtJ3ExJ0jch9olQOXEq5R4o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728614AbgIUQi4 (ORCPT ); Mon, 21 Sep 2020 12:38:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:40380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729202AbgIUQi4 (ORCPT ); Mon, 21 Sep 2020 12:38:56 -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 BE1A4238E6; Mon, 21 Sep 2020 16:38:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706334; bh=xWfbtvQi6jRbi8I/P0rqnE1igmz3Uiqjn4b6VweDl4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VMBw+NxRFQkp3Jm56pdYKgZ3rTGydrgGlsw5Jc32fncFDC8v40lini5NpbVTkhb5M GOjX94mk8JRyiVZ44bdJtc6SVWBz+qMaBJeYVhV5FpeuIExzqfZbPiQeGAmemV1XKs 3zgQdpOjuzFKeUk5W0W+Kk3fuMrkDo+uOfsrieHM= 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_Lindahl?= , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.14 28/94] iio:adc:ti-adc084s021 Fix alignment and data leak issues. Date: Mon, 21 Sep 2020 18:27:15 +0200 Message-Id: <20200921162036.847880785@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 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 @@ -28,6 +28,11 @@ 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. @@ -143,14 +148,13 @@ 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);