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[23.128.96.18]) by mx.google.com with ESMTP id cf15si10810462edb.350.2020.07.20.09.43.54; Mon, 20 Jul 2020 09:43:55 -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=pleLd+oj; 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 S1729984AbgGTQnu (ORCPT + 15 others); Mon, 20 Jul 2020 12:43:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:34280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729324AbgGTPlw (ORCPT ); Mon, 20 Jul 2020 11:41:52 -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 16E6E22CB3; Mon, 20 Jul 2020 15:41:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595259711; bh=Vk7IagyqnoRmnENC1u/iaiaXIz648HETL5Ky4FZuhwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pleLd+oj1Z1OLKcHxcOHqSQYtCigmcEwgDAYmzxEGIkfVT3sCw/KNM2Mb8Q3lTb86 uYWMCn9B0SxKAQWu+hJwwOguRfLsQB2lFkGXdzYl3WtsN9YvZu7qVzRRZq4Bv+Z4CK gGzFGWvNUnsixtkmY0P4LOjdUJ+YlDS4SCD2Zn5A= 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" , Sasha Levin Subject: [PATCH 4.9 52/86] iio:health:afe4404 Fix timestamp alignment and prevent data leak. Date: Mon, 20 Jul 2020 17:36:48 +0200 Message-Id: <20200720152755.782160784@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720152753.138974850@linuxfoundation.org> References: <20200720152753.138974850@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 [ Upstream commit f88ecccac4be348bbcc6d056bdbc622a8955c04d ] 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 40 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: 87aec56e27ef ("iio: health: Add driver for the TI AFE4404 heart monitor") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Acked-by: Andrew F. Davis Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/health/afe4404.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 2.25.1 diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c index 964f5231a831c..5e256b11ac877 100644 --- a/drivers/iio/health/afe4404.c +++ b/drivers/iio/health/afe4404.c @@ -91,6 +91,7 @@ static const struct reg_field afe4404_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 a scan to push to the iio buffer. */ struct afe4404_data { struct device *dev; @@ -99,6 +100,7 @@ struct afe4404_data { struct regulator *regulator; struct iio_trigger *trig; int irq; + s32 buffer[10] __aligned(8); }; enum afe4404_chan_id { @@ -337,17 +339,17 @@ static irqreturn_t afe4404_trigger_handler(int irq, void *private) struct iio_dev *indio_dev = pf->indio_dev; struct afe4404_data *afe = iio_priv(indio_dev); int ret, bit, i = 0; - s32 buffer[10]; for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) { ret = regmap_read(afe->regmap, afe4404_channel_values[bit], - &buffer[i++]); + &afe->buffer[i++]); 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);