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From: Jonathan Cameron <jic23@kernel.org>
To: linux-iio@vger.kernel.org
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald <pmeerw@pmeerw.net>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH v3 09/27] iio:light:max44000 Fix timestamp alignment and prevent data leak.
Date: Wed, 22 Jul 2020 16:50:45 +0100	[thread overview]
Message-ID: <20200722155103.979802-10-jic23@kernel.org> (raw)
In-Reply-To: <20200722155103.979802-1-jic23@kernel.org>

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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 16 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().
This data is allocated with kzalloc so no data can leak appart
from previous readings.

It is necessary to force the alignment of ts to avoid the padding
on x86_32 being different from 64 bit platorms (it alows for
4 bytes aligned 8 byte types.

Fixes: 06ad7ea10e2b ("max44000: Initial triggered buffer support")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/light/max44000.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
index aa8ed1e3e89a..b8e721bced5b 100644
--- a/drivers/iio/light/max44000.c
+++ b/drivers/iio/light/max44000.c
@@ -75,6 +75,11 @@
 struct max44000_data {
 	struct mutex lock;
 	struct regmap *regmap;
+	/* Ensure naturally aligned timestamp */
+	struct {
+		u16 channels[2];
+		s64 ts __aligned(8);
+	} scan;
 };
 
 /* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
@@ -488,7 +493,6 @@ static irqreturn_t max44000_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct max44000_data *data = iio_priv(indio_dev);
-	u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */
 	int index = 0;
 	unsigned int regval;
 	int ret;
@@ -498,17 +502,17 @@ static irqreturn_t max44000_trigger_handler(int irq, void *p)
 		ret = max44000_read_alsval(data);
 		if (ret < 0)
 			goto out_unlock;
-		buf[index++] = ret;
+		data->scan.channels[index++] = ret;
 	}
 	if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) {
 		ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, &regval);
 		if (ret < 0)
 			goto out_unlock;
-		buf[index] = regval;
+		data->scan.channels[index] = regval;
 	}
 	mutex_unlock(&data->lock);
 
-	iio_push_to_buffers_with_timestamp(indio_dev, buf,
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 					   iio_get_time_ns(indio_dev));
 	iio_trigger_notify_done(indio_dev->trig);
 	return IRQ_HANDLED;
-- 
2.27.0


  parent reply	other threads:[~2020-07-22 15:53 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22 15:50 [PATCH v3 00/27] IIO: Fused set 1 and 2 of timestamp alignment fixes Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 01/27] iio: accel: kxsd9: Fix alignment of local buffer Jonathan Cameron
2020-08-09 17:07   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 02/27] iio:accel:mma8452: Fix timestamp alignment and prevent data leak Jonathan Cameron
2020-08-09 17:14   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 03/27] iio:accel:bmc150-accel: " Jonathan Cameron
2020-07-29 17:12   ` Srinivas Pandruvada
2020-08-09 17:18     ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 04/27] iio:accel:mma7455: " Jonathan Cameron
2020-08-09 17:19   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 05/27] iio:gyro:itg3200: " Jonathan Cameron
2020-09-19 15:41   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 06/27] iio:proximity:mb1232: " Jonathan Cameron
2020-08-09 17:20   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 07/27] iio:chemical:ccs811: " Jonathan Cameron
2020-08-09 17:23   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 08/27] iio:light:si1145: " Jonathan Cameron
2020-07-22 19:43   ` Andy Shevchenko
2020-07-22 19:45     ` Andy Shevchenko
2020-07-23 11:25       ` Jonathan Cameron
2020-09-19 15:46         ` Jonathan Cameron
2020-07-22 15:50 ` Jonathan Cameron [this message]
2020-08-09 17:24   ` [PATCH v3 09/27] iio:light:max44000 " Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 10/27] iio:light:rpr0521 " Jonathan Cameron
2020-07-22 19:47   ` Andy Shevchenko
2020-07-23 11:29     ` Jonathan Cameron
2020-09-19 16:31       ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 11/27] iio:light:st_uvis25 " Jonathan Cameron
2020-07-22 19:48   ` Andy Shevchenko
2020-07-22 15:50 ` [PATCH v3 12/27] iio:light:ltr501 Fix timestamp alignment issue Jonathan Cameron
2020-08-09 17:27   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 13/27] iio:magnetometer:ak8975 Fix alignment and data leak issues Jonathan Cameron
2020-08-09 17:30   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 14/27] iio:magnetometer:mag3110 " Jonathan Cameron
2020-07-23 12:13   ` Andy Shevchenko
2020-07-22 15:50 ` [PATCH v3 15/27] iio:imu:bmi160 " Jonathan Cameron
2020-09-19 15:58   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 16/27] iio:imu:st_lsm6dsx " Jonathan Cameron
2020-09-19 16:09   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 17/27] iio:imu:inv_mpu6050 Fix dma and ts " Jonathan Cameron
2020-07-24  8:27   ` Jean-Baptiste Maneyrol
2020-09-19 16:51     ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 18/27] iio:imu:inv_mpu6050: Use regmap_noinc_read for fifo reads Jonathan Cameron
2020-07-23 12:15   ` Andy Shevchenko
2020-07-23 12:28     ` Jonathan Cameron
2020-07-24  8:29   ` Jean-Baptiste Maneyrol
2020-09-19 16:55     ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 19/27] iio:pressure:mpl3115 Force alignment of buffer Jonathan Cameron
2020-07-23 12:17   ` Andy Shevchenko
2020-07-23 12:31     ` Jonathan Cameron
2020-09-19 17:02       ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 20/27] iio:adc:ti-adc081c Fix alignment and data leak issues Jonathan Cameron
2020-08-09 17:34   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 21/27] iio:adc:ti-adc084s021 " Jonathan Cameron
2020-08-09 17:36   ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 22/27] iio:adc:ti-adc084s021 Tidy up endian types Jonathan Cameron
2020-08-09 17:47   ` Jonathan Cameron
2020-09-13 12:01     ` Jonathan Cameron
2020-09-13 12:06       ` Jonathan Cameron
2020-11-29 13:28         ` Jonathan Cameron
2020-07-22 15:50 ` [PATCH v3 23/27] iio:adc:ti-ads124s08 Fix alignment and data leak issues Jonathan Cameron
2020-07-22 20:54   ` Andy Shevchenko
2020-07-23 11:23     ` Jonathan Cameron
2020-07-22 15:51 ` [PATCH v3 24/27] iio:adc:ti-adc0832 Fix alignment issue with timestamp Jonathan Cameron
2020-09-19 16:18   ` Jonathan Cameron
2020-07-22 15:51 ` [PATCH v3 25/27] iio:adc:ti-adc12138 " Jonathan Cameron
2020-09-19 16:21   ` Jonathan Cameron
2020-07-22 15:51 ` [PATCH v3 26/27] iio:adc:ina2xx Fix timestamp alignment issue Jonathan Cameron
2020-08-09 17:38   ` Jonathan Cameron
2020-07-22 15:51 ` [PATCH v3 27/27] iio:adc:max1118 Fix alignment of timestamp and data leak issues Jonathan Cameron
2020-08-09 17:39   ` Jonathan Cameron
2020-07-23 12:23 ` [PATCH v3 00/27] IIO: Fused set 1 and 2 of timestamp alignment fixes Andy Shevchenko

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