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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 DBE43C433E0 for ; Sun, 17 May 2020 19:08:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4BC420709 for ; Sun, 17 May 2020 19:08:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726280AbgEQTIv (ORCPT ); Sun, 17 May 2020 15:08:51 -0400 Received: from smtpout1.mo528.mail-out.ovh.net ([46.105.34.251]:49675 "EHLO smtpout1.mo528.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbgEQTIv (ORCPT ); Sun, 17 May 2020 15:08:51 -0400 Received: from pro2.mail.ovh.net (unknown [10.108.1.143]) by mo528.mail-out.ovh.net (Postfix) with ESMTPS id 3B9835E1A4B8; Sun, 17 May 2020 21:08:48 +0200 (CEST) Received: from localhost (34.99.246.4) by DAG2EX1.emp2.local (172.16.2.11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Sun, 17 May 2020 21:08:47 +0200 Date: Sun, 17 May 2020 21:06:55 +0200 From: Tomasz Duszynski To: CC: , Jonathan Cameron , Lars-Peter Clausen , Tomasz Duszynski Subject: Re: [PATCH 11/11] iio:chemical:pms7003: Fix timestamp alignment and prevent data leak. Message-ID: <20200517190655.GA18033@arch> References: <20200517173000.220819-1-jic23@kernel.org> <20200517173000.220819-12-jic23@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <20200517173000.220819-12-jic23@kernel.org> X-Originating-IP: [34.99.246.4] X-ClientProxiedBy: DAG1EX1.emp2.local (172.16.2.1) To DAG2EX1.emp2.local (172.16.2.11) X-Ovh-Tracer-Id: 10070048767487466578 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduhedruddtfedgudefvdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpeffhffvuffkfhggtggujghisehttdertddttdejnecuhfhrohhmpefvohhmrghsiicuffhushiihihnshhkihcuoehtohhmrghsiidrughushiihihnshhkihesohgtthgrkhhonhdrtghomheqnecuggftrfgrthhtvghrnheptdehveethfffudetjeeftdekueehjeegjedvteffgfevkefffeegffeugeehgfejnecukfhppedtrddtrddtrddtpdefgedrleelrddvgeeirdegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmohguvgepshhmthhpqdhouhhtpdhhvghlohepphhrohdvrdhmrghilhdrohhvhhdrnhgvthdpihhnvghtpedtrddtrddtrddtpdhmrghilhhfrhhomhepthhomhgrshiirdguuhhsiiihnhhskhhisehotghtrghkohhnrdgtohhmpdhrtghpthhtohepthguuhhsiiihnhhssehgmhgrihhlrdgtohhm Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sun, May 17, 2020 at 06:30:00PM +0100, 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 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() data with alignment > explicitly requested. This data is allocated with kzalloc so no > data can leak appart from previous readings. > > Fixes: a1d642266c14 ("iio: chemical: add support for Plantower PMS7003 sensor") > Reported-by: Lars-Peter Clausen > Signed-off-by: Jonathan Cameron > Cc: Tomasz Duszynski > --- > drivers/iio/chemical/pms7003.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c > index 23c9ab252470..07bb90d72434 100644 > --- a/drivers/iio/chemical/pms7003.c > +++ b/drivers/iio/chemical/pms7003.c > @@ -73,6 +73,11 @@ struct pms7003_state { > struct pms7003_frame frame; > struct completion frame_ready; > struct mutex lock; /* must be held whenever state gets touched */ > + /* Used to construct scan to push to the IIO buffer */ > + struct { > + u16 data[3]; /* PM1, PM2P5, PM10 */ > + s64 ts; > + } scan; > }; > > static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd) > @@ -104,7 +109,6 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > struct iio_dev *indio_dev = pf->indio_dev; > struct pms7003_state *state = iio_priv(indio_dev); > struct pms7003_frame *frame = &state->frame; > - u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */ > int ret; > > mutex_lock(&state->lock); > @@ -114,12 +118,15 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > goto err; > } > > - data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > - data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > - data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > + state->scan.data[PM1] = > + pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > + state->scan.data[PM2P5] = > + pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > + state->scan.data[PM10] = > + pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > mutex_unlock(&state->lock); > > - iio_push_to_buffers_with_timestamp(indio_dev, data, > + iio_push_to_buffers_with_timestamp(indio_dev, &state->scan, > iio_get_time_ns(indio_dev)); > err: > iio_trigger_notify_done(indio_dev->trig); > -- > 2.26.2 > Thanks for the fix. Acked-by: Tomasz Duszynski