diff options
author | 2020-07-22 16:50:45 +0100 | |
---|---|---|
committer | 2020-08-22 11:38:57 +0100 | |
commit | 523628852a5f5f34a15252b2634d0498d3cfb347 (patch) | |
tree | 4fed87f8ee7c1823b04b0d839fd6d365c0bcc060 /drivers/iio/light | |
parent | iio:chemical:ccs811: Fix timestamp alignment and prevent data leak. (diff) | |
download | linux-523628852a5f5f34a15252b2634d0498d3cfb347.tar.gz linux-523628852a5f5f34a15252b2634d0498d3cfb347.tar.bz2 linux-523628852a5f5f34a15252b2634d0498d3cfb347.zip |
iio:light:max44000 Fix timestamp alignment and prevent data leak.
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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: <Stable@vger.kernel.org>
Diffstat (limited to 'drivers/iio/light')
-rw-r--r-- | drivers/iio/light/max44000.c | 12 |
1 files 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, ®val); 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; |