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media: video-i2c: avoid accessing released memory area when removing driver 

The video device release() callback for video-i2c driver frees the whole
struct video_i2c_data.  If there is no user left for the video device
when video_unregister_device() is called, the release callback is executed.

However, in video_i2c_remove() some fields (v4l2_dev, lock, and queue_lock)
in struct video_i2c_data are still accessed after video_unregister_device()
is called.

This fixes the use after free by moving the code from video_i2c_remove()
to the release() callback.

Fixes: 5cebaac609 ("media: video-i2c: add video-i2c driver")

Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Akinobu Mita 2018-10-20 10:26:23 -04:00 committed by Mauro Carvalho Chehab
parent 8e782fcf78
commit c764da98a6
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/media/i2c/video-i2c.c
View File

@ -510,7 +510,12 @@ static const struct v4l2_ioctl_ops video_i2c_ioctl_ops = {
static void video_i2c_release(struct video_device *vdev)
{
kfree(video_get_drvdata(vdev));
struct video_i2c_data *data = video_get_drvdata(vdev);
v4l2_device_unregister(&data->v4l2_dev);
mutex_destroy(&data->lock);
mutex_destroy(&data->queue_lock);
kfree(data);
}
static int video_i2c_probe(struct i2c_client *client,
@ -608,10 +613,6 @@ static int video_i2c_remove(struct i2c_client *client)
struct video_i2c_data *data = i2c_get_clientdata(client);
video_unregister_device(&data->vdev);
v4l2_device_unregister(&data->v4l2_dev);
mutex_destroy(&data->lock);
mutex_destroy(&data->queue_lock);
return 0;
}