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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3B722C433DF for ; Mon, 18 May 2020 00:10:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EB70206F4 for ; Mon, 18 May 2020 00:10:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="hie88stx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726671AbgERAKN (ORCPT ); Sun, 17 May 2020 20:10:13 -0400 Received: from fllv0015.ext.ti.com ([198.47.19.141]:60152 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726246AbgERAKN (ORCPT ); Sun, 17 May 2020 20:10:13 -0400 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 04I09mdC067061; Sun, 17 May 2020 19:09:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1589760588; bh=uHDWAbUPh1UGoZfwAFTrqfN3qYQnLykoq0dvdTPuMFA=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=hie88stxMbkiRMXvjASjMp+Rxx2NDl6Y2cpBzHn6wOflat+IURp5MOcpRSi+NtniO sNnbNTJzql8Zo0zC09SnTonGw/tJunXNeAwd5McnI0QhDpqde8dxx7fz+wEogb+Eic OrMklhQ0gapcqmkCQlWZZ+S9SgViCV130LytuZqA= Received: from DLEE109.ent.ti.com (dlee109.ent.ti.com [157.170.170.41]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 04I09mMQ006889 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Sun, 17 May 2020 19:09:48 -0500 Received: from DLEE115.ent.ti.com (157.170.170.26) by DLEE109.ent.ti.com (157.170.170.41) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Sun, 17 May 2020 19:09:48 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Sun, 17 May 2020 19:09:48 -0500 Received: from [10.250.38.163] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 04I09lUg027513; Sun, 17 May 2020 19:09:48 -0500 Subject: Re: [PATCH 07/11] iio:health:afe4403 Fix timestamp alignment and prevent data leak. To: , CC: Jonathan Cameron , Lars-Peter Clausen References: <20200517173000.220819-1-jic23@kernel.org> <20200517173000.220819-8-jic23@kernel.org> From: "Andrew F. Davis" Message-ID: <951a305b-b3b4-6cfc-f39a-f7458dfcb54b@ti.com> Date: Sun, 17 May 2020 20:09:47 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200517173000.220819-8-jic23@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On 5/17/20 1:29 PM, jic23@kernel.org wrote: > 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 32 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 structure 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: eec96d1e2d31 ("iio: health: Add driver for the TI AFE4403 heart monitor") > Reported-by: Lars-Peter Clausen > Signed-off-by: Jonathan Cameron > Cc: Andrew F. Davis > --- > drivers/iio/health/afe4403.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c > index e9f87e42ff4f..a3507624b30f 100644 > --- a/drivers/iio/health/afe4403.c > +++ b/drivers/iio/health/afe4403.c > @@ -65,6 +65,7 @@ static const struct reg_field afe4403_reg_fields[] = { > * @regulator: Pointer to the regulator for the IC > * @trig: IIO trigger for this device > * @irq: ADC_RDY line interrupt number > + * @buffer: Used to construct data layout to push into IIO buffer. > */ > struct afe4403_data { > struct device *dev; > @@ -74,6 +75,8 @@ struct afe4403_data { > struct regulator *regulator; > struct iio_trigger *trig; > int irq; > + /* Ensure suitable alignment for timestamp */ > + s32 buffer[8] __aligned(8); One of those fancy structs with the timestamp specified would be nice here like the other patches. IIRC we have 6 s32 channels, plus a s64 ts. Other than that everything looks good. Andrew > }; > > enum afe4403_chan_id { > @@ -309,7 +312,6 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) > struct iio_dev *indio_dev = pf->indio_dev; > struct afe4403_data *afe = iio_priv(indio_dev); > int ret, bit, i = 0; > - s32 buffer[8]; > u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ}; > u8 rx[3]; > > @@ -326,7 +328,7 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) > if (ret) > goto err; > > - buffer[i++] = get_unaligned_be24(&rx[0]); > + afe->buffer[i++] = get_unaligned_be24(&rx[0]); > } > > /* Disable reading from the device */ > @@ -335,7 +337,8 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) > if (ret) > goto err; > > - iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp); > + iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer, > + pf->timestamp); > err: > iio_trigger_notify_done(indio_dev->trig); > >