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| author | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-05-17 18:29:56 +0100 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-06-14 12:32:22 +0100 |
| commit | 3f9c6d38797e9903937b007a341dad0c251765d6 (patch) | |
| tree | 8ad3c8d5daf0fe9cdef43b74483772152d652228 /drivers/iio/health/afe4403.c | |
| parent | b791d1bdf9212d944d749a5c7ff6febdba241771 (diff) | |
| download | linux-3f9c6d38797e9903937b007a341dad0c251765d6.tar.bz2 | |
iio:health:afe4403 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 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 <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Andrew F. Davis <afd@ti.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio/health/afe4403.c')
| -rw-r--r-- | drivers/iio/health/afe4403.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c index e9f87e42ff4f..a3507624b30f 100644 --- a/drivers/iio/health/afe4403.c +++ b/drivers/iio/health/afe4403.c @@ -65,6 +65,7 @@ static const struct reg_field afe4403_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 data layout to push into IIO buffer. */ struct afe4403_data { struct device *dev; @@ -74,6 +75,8 @@ 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 { @@ -309,7 +312,6 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) 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]; @@ -326,7 +328,7 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) if (ret) goto err; - buffer[i++] = get_unaligned_be24(&rx[0]); + afe->buffer[i++] = get_unaligned_be24(&rx[0]); } /* Disable reading from the device */ @@ -335,7 +337,8 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) 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); |