| From 3f9c6d38797e9903937b007a341dad0c251765d6 Mon Sep 17 00:00:00 2001 |
| From: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Date: Sun, 17 May 2020 18:29:56 +0100 |
| Subject: iio:health:afe4403 Fix timestamp alignment and prevent data leak. |
| |
| From: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| |
| commit 3f9c6d38797e9903937b007a341dad0c251765d6 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 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/iio/health/afe4403.c | 13 ++++++++----- |
| 1 file changed, 8 insertions(+), 5 deletions(-) |
| |
| --- a/drivers/iio/health/afe4403.c |
| +++ b/drivers/iio/health/afe4403.c |
| @@ -71,6 +71,7 @@ static const struct reg_field afe4403_re |
| * @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; |
| @@ -80,6 +81,8 @@ 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 { |
| @@ -318,7 +321,6 @@ static irqreturn_t afe4403_trigger_handl |
| 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]; |
| |
| @@ -335,9 +337,9 @@ static irqreturn_t afe4403_trigger_handl |
| if (ret) |
| goto err; |
| |
| - buffer[i++] = (rx[0] << 16) | |
| - (rx[1] << 8) | |
| - (rx[2]); |
| + afe->buffer[i++] = (rx[0] << 16) | |
| + (rx[1] << 8) | |
| + (rx[2]); |
| } |
| |
| /* Disable reading from the device */ |
| @@ -346,7 +348,8 @@ static irqreturn_t afe4403_trigger_handl |
| 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); |
| |