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staging:iio:dummy: Fix potential NULL pointer dereference 

If the config contains CONFIG_IIO_BUFFER=y and CONFIG_IIO_SIMPLE_DUMMY_BUFFER=n
iio_simple_dummy_configure_buffer() is stubbed out and iio_buffer_register() is
not. As a result we try to register a buffer which has not been configured.
This will causes a NULL pointer deref in iio_buffer_register. To solve this
issue move the iio_buffer_register() call to iio_simple_dummy_configure_buffer(),
so it will only be called if iio_simple_dummy_configure_buffer() has been called.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2012-09-12 12:06:00 +01:00 committed by Jonathan Cameron
parent e60fea794e
commit 3fff227436
3 changed files with 22 additions and 17 deletions
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22
drivers/staging/iio/iio_simple_dummy.c
View File

@ -445,26 +445,20 @@ static int __devinit iio_dummy_probe(int index)
if (ret < 0)
goto error_free_device;
/* Configure buffered capture support. */
ret = iio_simple_dummy_configure_buffer(indio_dev);
/*
* Configure buffered capture support and register the channels with the
* buffer, but avoid the output channel being registered by reducing the
* number of channels by 1.
*/
ret = iio_simple_dummy_configure_buffer(indio_dev, iio_dummy_channels, 5);
if (ret < 0)
goto error_unregister_events;
/*
* Register the channels with the buffer, but avoid the output
* channel being registered by reducing the number of channels by 1.
*/
ret = iio_buffer_register(indio_dev, iio_dummy_channels, 5);
ret = iio_device_register(indio_dev);
if (ret < 0)
goto error_unconfigure_buffer;
ret = iio_device_register(indio_dev);
if (ret < 0)
goto error_unregister_buffer;
return 0;
error_unregister_buffer:
iio_buffer_unregister(indio_dev);
error_unconfigure_buffer:
iio_simple_dummy_unconfigure_buffer(indio_dev);
error_unregister_events:
@ -499,7 +493,6 @@ static int iio_dummy_remove(int index)
/* Device specific code to power down etc */
/* Buffered capture related cleanup */
iio_buffer_unregister(indio_dev);
iio_simple_dummy_unconfigure_buffer(indio_dev);
ret = iio_simple_dummy_events_unregister(indio_dev);
@ -530,6 +523,7 @@ static __init int iio_dummy_init(void)
instances = 1;
return -EINVAL;
}
/* Fake a bus */
iio_dummy_devs = kcalloc(instances, sizeof(*iio_dummy_devs),
GFP_KERNEL);

6
drivers/staging/iio/iio_simple_dummy.h
View File

@ -95,10 +95,12 @@ enum iio_simple_dummy_scan_elements {
};
#ifdef CONFIG_IIO_SIMPLE_DUMMY_BUFFER
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev);
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels, unsigned int num_channels);
void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev);
#else
static inline int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
static inline int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels, unsigned int num_channels)
{
return 0;
};

11
drivers/staging/iio/iio_simple_dummy_buffer.c
View File

@ -126,7 +126,8 @@ static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {
.predisable = &iio_triggered_buffer_predisable,
};
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels, unsigned int num_channels)
{
int ret;
struct iio_buffer *buffer;
@ -182,8 +183,15 @@ int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
* driven by a trigger.
*/
indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
ret = iio_buffer_register(indio_dev, channels, num_channels);
if (ret)
goto error_dealloc_pollfunc;
return 0;
error_dealloc_pollfunc:
iio_dealloc_pollfunc(indio_dev->pollfunc);
error_free_buffer:
iio_kfifo_free(indio_dev->buffer);
error_ret:
@ -197,6 +205,7 @@ error_ret:
*/
void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
{
iio_buffer_unregister(indio_dev);
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_kfifo_free(indio_dev->buffer);
}