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Commit 3fff2274 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

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: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent e60fea79

drivers/staging/iio/iio_simple_dummy.c

+7 −13
Original line number Diff line number Diff line
@@ -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);

	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.

	 * 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_buffer_register(indio_dev, iio_dummy_channels, 5);

	ret = iio_simple_dummy_configure_buffer(indio_dev, iio_dummy_channels, 5);

	if (ret < 0)

		goto error_unconfigure_buffer;

		goto error_unregister_events;



	ret = iio_device_register(indio_dev);

	if (ret < 0)

		goto error_unregister_buffer;

		goto error_unconfigure_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);

drivers/staging/iio/iio_simple_dummy.h

+4 −2
Original line number Diff line number Diff line
@@ -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;

};

drivers/staging/iio/iio_simple_dummy_buffer.c

+10 −1
Original line number Diff line number Diff line
@@ -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);

}