| Message ID | 20200517173000.220819-12-jic23@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | IIO: 1st set of timestamp alignment fixes. | expand |
On Sun, May 17, 2020 at 06:30:00PM +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 an 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: a1d642266c14 ("iio: chemical: add support for Plantower PMS7003 sensor") > Reported-by: Lars-Peter Clausen <lars@metafoo.de> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > Cc: Tomasz Duszynski <tduszyns@gmail.com> > --- > drivers/iio/chemical/pms7003.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c > index 23c9ab252470..07bb90d72434 100644 > --- a/drivers/iio/chemical/pms7003.c > +++ b/drivers/iio/chemical/pms7003.c > @@ -73,6 +73,11 @@ struct pms7003_state { > struct pms7003_frame frame; > struct completion frame_ready; > struct mutex lock; /* must be held whenever state gets touched */ > + /* Used to construct scan to push to the IIO buffer */ > + struct { > + u16 data[3]; /* PM1, PM2P5, PM10 */ > + s64 ts; > + } scan; > }; > > static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd) > @@ -104,7 +109,6 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > struct iio_dev *indio_dev = pf->indio_dev; > struct pms7003_state *state = iio_priv(indio_dev); > struct pms7003_frame *frame = &state->frame; > - u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */ > int ret; > > mutex_lock(&state->lock); > @@ -114,12 +118,15 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > goto err; > } > > - data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > - data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > - data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > + state->scan.data[PM1] = > + pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > + state->scan.data[PM2P5] = > + pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > + state->scan.data[PM10] = > + pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > mutex_unlock(&state->lock); > > - iio_push_to_buffers_with_timestamp(indio_dev, data, > + iio_push_to_buffers_with_timestamp(indio_dev, &state->scan, > iio_get_time_ns(indio_dev)); > err: > iio_trigger_notify_done(indio_dev->trig); > -- > 2.26.2 > Thanks for the fix. Acked-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
On Sun, 17 May 2020 21:06:55 +0200 Tomasz Duszynski <tomasz.duszynski@octakon.com> wrote: > On Sun, May 17, 2020 at 06:30:00PM +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 an 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: a1d642266c14 ("iio: chemical: add support for Plantower PMS7003 sensor") > > Reported-by: Lars-Peter Clausen <lars@metafoo.de> > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > > Cc: Tomasz Duszynski <tduszyns@gmail.com> > > --- > > drivers/iio/chemical/pms7003.c | 17 ++++++++++++----- > > 1 file changed, 12 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c > > index 23c9ab252470..07bb90d72434 100644 > > --- a/drivers/iio/chemical/pms7003.c > > +++ b/drivers/iio/chemical/pms7003.c > > @@ -73,6 +73,11 @@ struct pms7003_state { > > struct pms7003_frame frame; > > struct completion frame_ready; > > struct mutex lock; /* must be held whenever state gets touched */ > > + /* Used to construct scan to push to the IIO buffer */ > > + struct { > > + u16 data[3]; /* PM1, PM2P5, PM10 */ > > + s64 ts; > > + } scan; > > }; > > > > static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd) > > @@ -104,7 +109,6 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > > struct iio_dev *indio_dev = pf->indio_dev; > > struct pms7003_state *state = iio_priv(indio_dev); > > struct pms7003_frame *frame = &state->frame; > > - u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */ > > int ret; > > > > mutex_lock(&state->lock); > > @@ -114,12 +118,15 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) > > goto err; > > } > > > > - data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > > - data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > > - data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > > + state->scan.data[PM1] = > > + pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); > > + state->scan.data[PM2P5] = > > + pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); > > + state->scan.data[PM10] = > > + pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); > > mutex_unlock(&state->lock); > > > > - iio_push_to_buffers_with_timestamp(indio_dev, data, > > + iio_push_to_buffers_with_timestamp(indio_dev, &state->scan, > > iio_get_time_ns(indio_dev)); > > err: > > iio_trigger_notify_done(indio_dev->trig); > > -- > > 2.26.2 > > > > Thanks for the fix. > Acked-by: Tomasz Duszynski <tomasz.duszynski@octakon.com> > Applied. Thanks,
diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c index 23c9ab252470..07bb90d72434 100644 --- a/drivers/iio/chemical/pms7003.c +++ b/drivers/iio/chemical/pms7003.c @@ -73,6 +73,11 @@ struct pms7003_state { struct pms7003_frame frame; struct completion frame_ready; struct mutex lock; /* must be held whenever state gets touched */ + /* Used to construct scan to push to the IIO buffer */ + struct { + u16 data[3]; /* PM1, PM2P5, PM10 */ + s64 ts; + } scan; }; static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd) @@ -104,7 +109,6 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) struct iio_dev *indio_dev = pf->indio_dev; struct pms7003_state *state = iio_priv(indio_dev); struct pms7003_frame *frame = &state->frame; - u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */ int ret; mutex_lock(&state->lock); @@ -114,12 +118,15 @@ static irqreturn_t pms7003_trigger_handler(int irq, void *p) goto err; } - data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); - data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); - data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); + state->scan.data[PM1] = + pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET); + state->scan.data[PM2P5] = + pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET); + state->scan.data[PM10] = + pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET); mutex_unlock(&state->lock); - iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_push_to_buffers_with_timestamp(indio_dev, &state->scan, iio_get_time_ns(indio_dev)); err: iio_trigger_notify_done(indio_dev->trig);