| From 0f386f0e32f4b145adc8410114cd0bbfe577c332 Mon Sep 17 00:00:00 2001 |
| From: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Date: Sun, 17 May 2020 18:29:57 +0100 |
| Subject: [PATCH] iio:health:afe4404 Fix timestamp alignment and prevent data |
| leak. |
| |
| commit f88ecccac4be348bbcc6d056bdbc622a8955c04d 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 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 <lars@metafoo.de> |
| Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Acked-by: Andrew F. Davis <afd@ti.com> |
| Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c |
| index e728bbb21ca8..cebb1fd4d0b1 100644 |
| --- a/drivers/iio/health/afe4404.c |
| +++ b/drivers/iio/health/afe4404.c |
| @@ -83,6 +83,7 @@ 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; |
| @@ -91,6 +92,7 @@ struct afe4404_data { |
| struct regulator *regulator; |
| struct iio_trigger *trig; |
| int irq; |
| + s32 buffer[10] __aligned(8); |
| }; |
| |
| enum afe4404_chan_id { |
| @@ -328,17 +330,17 @@ 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); |
| |
| -- |
| 2.27.0 |
| |