drivers/gpu/drm/drm_auth.c - arm/linux - Git at Google

 /*
  * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
  *
  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  * All Rights Reserved.
  *
  * Author Rickard E. (Rik) Faith <faith@valinux.com>
  * Author Gareth Hughes <gareth@valinux.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */

 #include <drm/drmP.h>
 #include "drm_internal.h"
 #include "drm_legacy.h"

 /**
  * DOC: master and authentication
  *
  * &struct drm_master is used to track groups of clients with open
  * primary/legacy device nodes. For every &struct drm_file which has had at
  * least once successfully became the device master (either through the
  * SET_MASTER IOCTL, or implicitly through opening the primary device node when
  * no one else is the current master that time) there exists one &drm_master.
  * This is noted in &drm_file.is_master. All other clients have just a pointer
  * to the &drm_master they are associated with.
  *
  * In addition only one &drm_master can be the current master for a &drm_device.
  * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
  * implicitly through closing/openeing the primary device node. See also
  * drm_is_current_master().
  *
  * Clients can authenticate against the current master (if it matches their own)
  * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
  * this allows controlled access to the device for an entire group of mutually
  * trusted clients.
  */

 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
 {
 	struct drm_auth *auth = data;
 	int ret = 0;

 	mutex_lock(&dev->master_mutex);
 	if (!file_priv->magic) {
 		ret = idr_alloc(&file_priv->master->magic_map, file_priv,
 				1, 0, GFP_KERNEL);
 		if (ret >= 0)
 			file_priv->magic = ret;
 	}
 	auth->magic = file_priv->magic;
 	mutex_unlock(&dev->master_mutex);

 	DRM_DEBUG("%u\n", auth->magic);

 	return ret < 0 ? ret : 0;
 }

 int drm_authmagic(struct drm_device *dev, void *data,
 		  struct drm_file *file_priv)
 {
 	struct drm_auth *auth = data;
 	struct drm_file *file;

 	DRM_DEBUG("%u\n", auth->magic);

 	mutex_lock(&dev->master_mutex);
 	file = idr_find(&file_priv->master->magic_map, auth->magic);
 	if (file) {
 		file->authenticated = 1;
 		idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
 	}
 	mutex_unlock(&dev->master_mutex);

 	return file ? 0 : -EINVAL;
 }

 static struct drm_master *drm_master_create(struct drm_device *dev)
 {
 	struct drm_master *master;

 	master = kzalloc(sizeof(*master), GFP_KERNEL);
 	if (!master)
 		return NULL;

 	kref_init(&master->refcount);
 	spin_lock_init(&master->lock.spinlock);
 	init_waitqueue_head(&master->lock.lock_queue);
 	idr_init(&master->magic_map);
 	master->dev = dev;

 	return master;
 }

 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
 			  bool new_master)
 {
 	int ret = 0;

 	dev->master = drm_master_get(fpriv->master);
 	if (dev->driver->master_set) {
 		ret = dev->driver->master_set(dev, fpriv, new_master);
 		if (unlikely(ret != 0)) {
 			drm_master_put(&dev->master);
 		}
 	}

 	return ret;
 }

 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
 {
 	struct drm_master *old_master;
 	int ret;

 	lockdep_assert_held_once(&dev->master_mutex);

 	old_master = fpriv->master;
 	fpriv->master = drm_master_create(dev);
 	if (!fpriv->master) {
 		fpriv->master = old_master;
 		return -ENOMEM;
 	}

 	if (dev->driver->master_create) {
 		ret = dev->driver->master_create(dev, fpriv->master);
 		if (ret)
 			goto out_err;
 	}
 	fpriv->is_master = 1;
 	fpriv->authenticated = 1;

 	ret = drm_set_master(dev, fpriv, true);
 	if (ret)
 		goto out_err;

 	if (old_master)
 		drm_master_put(&old_master);

 	return 0;

 out_err:
 	/* drop references and restore old master on failure */
 	drm_master_put(&fpriv->master);
 	fpriv->master = old_master;

 	return ret;
 }

 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv)
 {
 	int ret = 0;

 	mutex_lock(&dev->master_mutex);
 	if (drm_is_current_master(file_priv))
 		goto out_unlock;

 	if (dev->master) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	if (!file_priv->master) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	if (!file_priv->is_master) {
 		ret = drm_new_set_master(dev, file_priv);
 		goto out_unlock;
 	}

 	ret = drm_set_master(dev, file_priv, false);
 out_unlock:
 	mutex_unlock(&dev->master_mutex);
 	return ret;
 }

 static void drm_drop_master(struct drm_device *dev,
 			    struct drm_file *fpriv)
 {
 	if (dev->driver->master_drop)
 		dev->driver->master_drop(dev, fpriv);
 	drm_master_put(&dev->master);
 }

 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	int ret = -EINVAL;

 	mutex_lock(&dev->master_mutex);
 	if (!drm_is_current_master(file_priv))
 		goto out_unlock;

 	if (!dev->master)
 		goto out_unlock;

 	ret = 0;
 	drm_drop_master(dev, file_priv);
 out_unlock:
 	mutex_unlock(&dev->master_mutex);
 	return ret;
 }

 int drm_master_open(struct drm_file *file_priv)
 {
 	struct drm_device *dev = file_priv->minor->dev;
 	int ret = 0;

 	/* if there is no current master make this fd it, but do not create
 	 * any master object for render clients */
 	mutex_lock(&dev->master_mutex);
 	if (!dev->master)
 		ret = drm_new_set_master(dev, file_priv);
 	else
 		file_priv->master = drm_master_get(dev->master);
 	mutex_unlock(&dev->master_mutex);

 	return ret;
 }

 void drm_master_release(struct drm_file *file_priv)
 {
 	struct drm_device *dev = file_priv->minor->dev;
 	struct drm_master *master = file_priv->master;

 	mutex_lock(&dev->master_mutex);
 	if (file_priv->magic)
 		idr_remove(&file_priv->master->magic_map, file_priv->magic);

 	if (!drm_is_current_master(file_priv))
 		goto out;

 	if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
 		/*
 		 * Since the master is disappearing, so is the
 		 * possibility to lock.
 		 */
 		mutex_lock(&dev->struct_mutex);
 		if (master->lock.hw_lock) {
 			if (dev->sigdata.lock == master->lock.hw_lock)
 				dev->sigdata.lock = NULL;
 			master->lock.hw_lock = NULL;
 			master->lock.file_priv = NULL;
 			wake_up_interruptible_all(&master->lock.lock_queue);
 		}
 		mutex_unlock(&dev->struct_mutex);
 	}

 	if (dev->master == file_priv->master)
 		drm_drop_master(dev, file_priv);
 out:
 	/* drop the master reference held by the file priv */
 	if (file_priv->master)
 		drm_master_put(&file_priv->master);
 	mutex_unlock(&dev->master_mutex);
 }

 /**
  * drm_is_current_master - checks whether @priv is the current master
  * @fpriv: DRM file private
  *
  * Checks whether @fpriv is current master on its device. This decides whether a
  * client is allowed to run DRM_MASTER IOCTLs.
  *
  * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
  * - the current master is assumed to own the non-shareable display hardware.
  */
 bool drm_is_current_master(struct drm_file *fpriv)
 {
 	return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
 }
 EXPORT_SYMBOL(drm_is_current_master);

 /**
  * drm_master_get - reference a master pointer
  * @master: &struct drm_master
  *
  * Increments the reference count of @master and returns a pointer to @master.
  */
 struct drm_master *drm_master_get(struct drm_master *master)
 {
 	kref_get(&master->refcount);
 	return master;
 }
 EXPORT_SYMBOL(drm_master_get);

 static void drm_master_destroy(struct kref *kref)
 {
 	struct drm_master *master = container_of(kref, struct drm_master, refcount);
 	struct drm_device *dev = master->dev;

 	if (dev->driver->master_destroy)
 		dev->driver->master_destroy(dev, master);

 	drm_legacy_master_rmmaps(dev, master);

 	idr_destroy(&master->magic_map);
 	kfree(master->unique);
 	kfree(master);
 }

 /**
  * drm_master_put - unreference and clear a master pointer
  * @master: pointer to a pointer of &struct drm_master
  *
  * This decrements the &drm_master behind @master and sets it to NULL.
  */
 void drm_master_put(struct drm_master **master)
 {
 	kref_put(&(*master)->refcount, drm_master_destroy);
 	*master = NULL;
 }
 EXPORT_SYMBOL(drm_master_put);
	/*
	* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
	*
	* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
	* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
	* All Rights Reserved.
	*
	* Author Rickard E. (Rik) Faith <faith@valinux.com>
	* Author Gareth Hughes <gareth@valinux.com>
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/

	#include <drm/drmP.h>
	#include "drm_internal.h"
	#include "drm_legacy.h"

	/**
	* DOC: master and authentication
	*
	* &struct drm_master is used to track groups of clients with open
	* primary/legacy device nodes. For every &struct drm_file which has had at
	* least once successfully became the device master (either through the
	* SET_MASTER IOCTL, or implicitly through opening the primary device node when
	* no one else is the current master that time) there exists one &drm_master.
	* This is noted in &drm_file.is_master. All other clients have just a pointer
	* to the &drm_master they are associated with.
	*
	* In addition only one &drm_master can be the current master for a &drm_device.
	* It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
	* implicitly through closing/openeing the primary device node. See also
	* drm_is_current_master().
	*
	* Clients can authenticate against the current master (if it matches their own)
	* using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
	* this allows controlled access to the device for an entire group of mutually
	* trusted clients.
	*/

	int drm_getmagic(struct drm_device dev, void data, struct drm_file *file_priv)
	{
	struct drm_auth *auth = data;
	int ret = 0;

	mutex_lock(&dev->master_mutex);
	if (!file_priv->magic) {
	ret = idr_alloc(&file_priv->master->magic_map, file_priv,
	1, 0, GFP_KERNEL);
	if (ret >= 0)
	file_priv->magic = ret;
	}
	auth->magic = file_priv->magic;
	mutex_unlock(&dev->master_mutex);

	DRM_DEBUG("%u\n", auth->magic);

	return ret < 0 ? ret : 0;
	}

	int drm_authmagic(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_auth *auth = data;
	struct drm_file *file;

	DRM_DEBUG("%u\n", auth->magic);

	mutex_lock(&dev->master_mutex);
	file = idr_find(&file_priv->master->magic_map, auth->magic);
	if (file) {
	file->authenticated = 1;
	idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
	}
	mutex_unlock(&dev->master_mutex);

	return file ? 0 : -EINVAL;
	}

	static struct drm_master drm_master_create(struct drm_device dev)
	{
	struct drm_master *master;

	master = kzalloc(sizeof(*master), GFP_KERNEL);
	if (!master)
	return NULL;

	kref_init(&master->refcount);
	spin_lock_init(&master->lock.spinlock);
	init_waitqueue_head(&master->lock.lock_queue);
	idr_init(&master->magic_map);
	master->dev = dev;

	return master;
	}

	static int drm_set_master(struct drm_device dev, struct drm_file fpriv,
	bool new_master)
	{
	int ret = 0;

	dev->master = drm_master_get(fpriv->master);
	if (dev->driver->master_set) {
	ret = dev->driver->master_set(dev, fpriv, new_master);
	if (unlikely(ret != 0)) {
	drm_master_put(&dev->master);
	}
	}

	return ret;
	}

	static int drm_new_set_master(struct drm_device dev, struct drm_file fpriv)
	{
	struct drm_master *old_master;
	int ret;

	lockdep_assert_held_once(&dev->master_mutex);

	old_master = fpriv->master;
	fpriv->master = drm_master_create(dev);
	if (!fpriv->master) {
	fpriv->master = old_master;
	return -ENOMEM;
	}

	if (dev->driver->master_create) {
	ret = dev->driver->master_create(dev, fpriv->master);
	if (ret)
	goto out_err;
	}
	fpriv->is_master = 1;
	fpriv->authenticated = 1;

	ret = drm_set_master(dev, fpriv, true);
	if (ret)
	goto out_err;

	if (old_master)
	drm_master_put(&old_master);

	return 0;

	out_err:
	/* drop references and restore old master on failure */
	drm_master_put(&fpriv->master);
	fpriv->master = old_master;

	return ret;
	}

	int drm_setmaster_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	int ret = 0;

	mutex_lock(&dev->master_mutex);
	if (drm_is_current_master(file_priv))
	goto out_unlock;

	if (dev->master) {
	ret = -EINVAL;
	goto out_unlock;
	}

	if (!file_priv->master) {
	ret = -EINVAL;
	goto out_unlock;
	}

	if (!file_priv->is_master) {
	ret = drm_new_set_master(dev, file_priv);
	goto out_unlock;
	}

	ret = drm_set_master(dev, file_priv, false);
	out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
	}

	static void drm_drop_master(struct drm_device *dev,
	struct drm_file *fpriv)
	{
	if (dev->driver->master_drop)
	dev->driver->master_drop(dev, fpriv);
	drm_master_put(&dev->master);
	}

	int drm_dropmaster_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	int ret = -EINVAL;

	mutex_lock(&dev->master_mutex);
	if (!drm_is_current_master(file_priv))
	goto out_unlock;

	if (!dev->master)
	goto out_unlock;

	ret = 0;
	drm_drop_master(dev, file_priv);
	out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
	}

	int drm_master_open(struct drm_file *file_priv)
	{
	struct drm_device *dev = file_priv->minor->dev;
	int ret = 0;

	/* if there is no current master make this fd it, but do not create
	* any master object for render clients */
	mutex_lock(&dev->master_mutex);
	if (!dev->master)
	ret = drm_new_set_master(dev, file_priv);
	else
	file_priv->master = drm_master_get(dev->master);
	mutex_unlock(&dev->master_mutex);

	return ret;
	}

	void drm_master_release(struct drm_file *file_priv)
	{
	struct drm_device *dev = file_priv->minor->dev;
	struct drm_master *master = file_priv->master;

	mutex_lock(&dev->master_mutex);
	if (file_priv->magic)
	idr_remove(&file_priv->master->magic_map, file_priv->magic);

	if (!drm_is_current_master(file_priv))
	goto out;

	if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
	/*
	* Since the master is disappearing, so is the
	* possibility to lock.
	*/
	mutex_lock(&dev->struct_mutex);
	if (master->lock.hw_lock) {
	if (dev->sigdata.lock == master->lock.hw_lock)
	dev->sigdata.lock = NULL;
	master->lock.hw_lock = NULL;
	master->lock.file_priv = NULL;
	wake_up_interruptible_all(&master->lock.lock_queue);
	}
	mutex_unlock(&dev->struct_mutex);
	}

	if (dev->master == file_priv->master)
	drm_drop_master(dev, file_priv);
	out:
	/* drop the master reference held by the file priv */
	if (file_priv->master)
	drm_master_put(&file_priv->master);
	mutex_unlock(&dev->master_mutex);
	}

	/**
	* drm_is_current_master - checks whether @priv is the current master
	* @fpriv: DRM file private
	*
	* Checks whether @fpriv is current master on its device. This decides whether a
	* client is allowed to run DRM_MASTER IOCTLs.
	*
	* Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
	* - the current master is assumed to own the non-shareable display hardware.
	*/
	bool drm_is_current_master(struct drm_file *fpriv)
	{
	return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
	}
	EXPORT_SYMBOL(drm_is_current_master);

	/**
	* drm_master_get - reference a master pointer
	* @master: &struct drm_master
	*
	* Increments the reference count of @master and returns a pointer to @master.
	*/
	struct drm_master drm_master_get(struct drm_master master)
	{
	kref_get(&master->refcount);
	return master;
	}
	EXPORT_SYMBOL(drm_master_get);

	static void drm_master_destroy(struct kref *kref)
	{
	struct drm_master *master = container_of(kref, struct drm_master, refcount);
	struct drm_device *dev = master->dev;

	if (dev->driver->master_destroy)
	dev->driver->master_destroy(dev, master);

	drm_legacy_master_rmmaps(dev, master);

	idr_destroy(&master->magic_map);
	kfree(master->unique);
	kfree(master);
	}

	/**
	* drm_master_put - unreference and clear a master pointer
	* @master: pointer to a pointer of &struct drm_master
	*
	* This decrements the &drm_master behind @master and sets it to NULL.
	*/
	void drm_master_put(struct drm_master **master)
	{
	kref_put(&(*master)->refcount, drm_master_destroy);
	*master = NULL;
	}
	EXPORT_SYMBOL(drm_master_put);