From 3fff22743640637c2b61473d3cc8d7dc2215984f Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Wed, 12 Sep 2012 12:06:00 +0100 Subject: [PATCH] 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 Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/staging/iio/iio_simple_dummy.c | 20 +++++++------------ drivers/staging/iio/iio_simple_dummy.h | 6 ++++-- drivers/staging/iio/iio_simple_dummy_buffer.c | 11 +++++++++- 3 files changed, 21 insertions(+), 16 deletions(-) diff --git a/drivers/staging/iio/iio_simple_dummy.c b/drivers/staging/iio/iio_simple_dummy.c index 029bcc67f16..dc6c728ea47 100644 --- a/drivers/staging/iio/iio_simple_dummy.c +++ b/drivers/staging/iio/iio_simple_dummy.c @@ -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); diff --git a/drivers/staging/iio/iio_simple_dummy.h b/drivers/staging/iio/iio_simple_dummy.h index 53975d916fc..c9e8702caca 100644 --- a/drivers/staging/iio/iio_simple_dummy.h +++ b/drivers/staging/iio/iio_simple_dummy.h @@ -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; }; diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c index 1fd38095b2c..697d9700db2 100644 --- a/drivers/staging/iio/iio_simple_dummy_buffer.c +++ b/drivers/staging/iio/iio_simple_dummy_buffer.c @@ -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); } -- 2.20.1