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[23.128.96.18]) by mx.google.com with ESMTP id y5si11201992edw.306.2020.07.20.08.52.18; Mon, 20 Jul 2020 08:52:18 -0700 (PDT) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="tC/VI29v"; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731345AbgGTPwR (ORCPT + 15 others); Mon, 20 Jul 2020 11:52:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:50024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731334AbgGTPwQ (ORCPT ); Mon, 20 Jul 2020 11:52:16 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 116A62065E; Mon, 20 Jul 2020 15:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595260335; bh=a22zVVN/NvJGBrt6FAWnyk1s+vGlWcTw0O9Xcqc6ys8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tC/VI29vpSgmueeUMcKM4JXBTnKlRvPVkgv2zDELM4xGkBmKfrm40/abZnlk2LmBy rr9MvyyZbICdvnf+INIECpz/j6d5Wa0+BeB++/gO4oiZ8gnYUNbSK74B4vCUQYmn+D vtY7wH4okoLa95FuN+fpIZOI8UkVIPExpfn9ncko= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , "Andrew F. Davis" , Stable@vger.kernel.org Subject: [PATCH 4.19 036/133] iio:health:afe4403 Fix timestamp alignment and prevent data leak. Date: Mon, 20 Jul 2020 17:36:23 +0200 Message-Id: <20200720152805.462507150@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720152803.732195882@linuxfoundation.org> References: <20200720152803.732195882@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit 3f9c6d38797e9903937b007a341dad0c251765d6 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 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 Acked-by: Andrew F. Davis Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/health/afe4403.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/drivers/iio/health/afe4403.c +++ b/drivers/iio/health/afe4403.c @@ -71,6 +71,7 @@ static const struct reg_field afe4403_re * @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; @@ -80,6 +81,8 @@ struct afe4403_data { struct regulator *regulator; struct iio_trigger *trig; int irq; + /* Ensure suitable alignment for timestamp */ + s32 buffer[8] __aligned(8); }; enum afe4403_chan_id { @@ -317,7 +320,6 @@ static irqreturn_t afe4403_trigger_handl 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]; @@ -334,9 +336,9 @@ static irqreturn_t afe4403_trigger_handl if (ret) goto err; - buffer[i++] = (rx[0] << 16) | - (rx[1] << 8) | - (rx[2]); + afe->buffer[i++] = (rx[0] << 16) | + (rx[1] << 8) | + (rx[2]); } /* Disable reading from the device */ @@ -345,7 +347,8 @@ static irqreturn_t afe4403_trigger_handl 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);