| Message ID | 20200517173000.220819-9-jic23@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | IIO: 1st set of timestamp alignment fixes. | expand |
On Sun, 17 May 2020 18:29:57 +0100 jic23@kernel.org wrote: > 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 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> > Cc: Andrew F. Davis <afd@ti.com> Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan > --- > drivers/iio/health/afe4404.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > 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); >
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);