Commit c996fd0b authored by Thomas Hellstrom's avatar Thomas Hellstrom

drm: Protect the master management with a drm_device::master_mutex v3

The master management was previously protected by the drm_device::struct_mutex.
In order to avoid locking order violations in a reworked dropped master
security check in the vmwgfx driver, break it out into a separate master_mutex.
Locking order is master_mutex -> struct_mutex.

Also remove drm_master::blocked since it's not used.

v2: Add an inline comment about what drm_device::master_mutex is protecting.
v3: Remove unneeded struct_mutex locks. Fix error returns in
    drm_setmaster_ioctl().
Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarBrian Paul <brianp@vmware.com>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: default avatarDaniel Vetter <daniel@ffwll.ch>
parent a12cd002
...@@ -231,12 +231,11 @@ static int drm_open_helper(struct inode *inode, struct file *filp, ...@@ -231,12 +231,11 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
/* if there is no current master make this fd it, but do not create /* if there is no current master make this fd it, but do not create
* any master object for render clients */ * any master object for render clients */
mutex_lock(&dev->struct_mutex); mutex_lock(&dev->master_mutex);
if (drm_is_primary_client(priv) && !priv->minor->master) { if (drm_is_primary_client(priv) && !priv->minor->master) {
/* create a new master */ /* create a new master */
priv->minor->master = drm_master_create(priv->minor); priv->minor->master = drm_master_create(priv->minor);
if (!priv->minor->master) { if (!priv->minor->master) {
mutex_unlock(&dev->struct_mutex);
ret = -ENOMEM; ret = -ENOMEM;
goto out_close; goto out_close;
} }
...@@ -244,29 +243,23 @@ static int drm_open_helper(struct inode *inode, struct file *filp, ...@@ -244,29 +243,23 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
priv->is_master = 1; priv->is_master = 1;
/* take another reference for the copy in the local file priv */ /* take another reference for the copy in the local file priv */
priv->master = drm_master_get(priv->minor->master); priv->master = drm_master_get(priv->minor->master);
priv->authenticated = 1; priv->authenticated = 1;
mutex_unlock(&dev->struct_mutex);
if (dev->driver->master_create) { if (dev->driver->master_create) {
ret = dev->driver->master_create(dev, priv->master); ret = dev->driver->master_create(dev, priv->master);
if (ret) { if (ret) {
mutex_lock(&dev->struct_mutex);
/* drop both references if this fails */ /* drop both references if this fails */
drm_master_put(&priv->minor->master); drm_master_put(&priv->minor->master);
drm_master_put(&priv->master); drm_master_put(&priv->master);
mutex_unlock(&dev->struct_mutex);
goto out_close; goto out_close;
} }
} }
mutex_lock(&dev->struct_mutex);
if (dev->driver->master_set) { if (dev->driver->master_set) {
ret = dev->driver->master_set(dev, priv, true); ret = dev->driver->master_set(dev, priv, true);
if (ret) { if (ret) {
/* drop both references if this fails */ /* drop both references if this fails */
drm_master_put(&priv->minor->master); drm_master_put(&priv->minor->master);
drm_master_put(&priv->master); drm_master_put(&priv->master);
mutex_unlock(&dev->struct_mutex);
goto out_close; goto out_close;
} }
} }
...@@ -274,7 +267,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp, ...@@ -274,7 +267,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
/* get a reference to the master */ /* get a reference to the master */
priv->master = drm_master_get(priv->minor->master); priv->master = drm_master_get(priv->minor->master);
} }
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->master_mutex);
mutex_lock(&dev->struct_mutex); mutex_lock(&dev->struct_mutex);
list_add(&priv->lhead, &dev->filelist); list_add(&priv->lhead, &dev->filelist);
...@@ -302,6 +295,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp, ...@@ -302,6 +295,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
return 0; return 0;
out_close: out_close:
mutex_unlock(&dev->master_mutex);
if (dev->driver->postclose) if (dev->driver->postclose)
dev->driver->postclose(dev, priv); dev->driver->postclose(dev, priv);
out_prime_destroy: out_prime_destroy:
...@@ -489,11 +483,13 @@ int drm_release(struct inode *inode, struct file *filp) ...@@ -489,11 +483,13 @@ int drm_release(struct inode *inode, struct file *filp)
} }
mutex_unlock(&dev->ctxlist_mutex); mutex_unlock(&dev->ctxlist_mutex);
mutex_lock(&dev->struct_mutex); mutex_lock(&dev->master_mutex);
if (file_priv->is_master) { if (file_priv->is_master) {
struct drm_master *master = file_priv->master; struct drm_master *master = file_priv->master;
struct drm_file *temp; struct drm_file *temp;
mutex_lock(&dev->struct_mutex);
list_for_each_entry(temp, &dev->filelist, lhead) { list_for_each_entry(temp, &dev->filelist, lhead) {
if ((temp->master == file_priv->master) && if ((temp->master == file_priv->master) &&
(temp != file_priv)) (temp != file_priv))
...@@ -512,6 +508,7 @@ int drm_release(struct inode *inode, struct file *filp) ...@@ -512,6 +508,7 @@ int drm_release(struct inode *inode, struct file *filp)
master->lock.file_priv = NULL; master->lock.file_priv = NULL;
wake_up_interruptible_all(&master->lock.lock_queue); wake_up_interruptible_all(&master->lock.lock_queue);
} }
mutex_unlock(&dev->struct_mutex);
if (file_priv->minor->master == file_priv->master) { if (file_priv->minor->master == file_priv->master) {
/* drop the reference held my the minor */ /* drop the reference held my the minor */
...@@ -521,10 +518,13 @@ int drm_release(struct inode *inode, struct file *filp) ...@@ -521,10 +518,13 @@ int drm_release(struct inode *inode, struct file *filp)
} }
} }
/* drop the reference held my the file priv */ /* drop the master reference held by the file priv */
if (file_priv->master) if (file_priv->master)
drm_master_put(&file_priv->master); drm_master_put(&file_priv->master);
file_priv->is_master = 0; file_priv->is_master = 0;
mutex_unlock(&dev->master_mutex);
mutex_lock(&dev->struct_mutex);
list_del(&file_priv->lhead); list_del(&file_priv->lhead);
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->struct_mutex);
......
...@@ -144,6 +144,7 @@ static void drm_master_destroy(struct kref *kref) ...@@ -144,6 +144,7 @@ static void drm_master_destroy(struct kref *kref)
struct drm_device *dev = master->minor->dev; struct drm_device *dev = master->minor->dev;
struct drm_map_list *r_list, *list_temp; struct drm_map_list *r_list, *list_temp;
mutex_lock(&dev->struct_mutex);
if (dev->driver->master_destroy) if (dev->driver->master_destroy)
dev->driver->master_destroy(dev, master); dev->driver->master_destroy(dev, master);
...@@ -171,6 +172,7 @@ static void drm_master_destroy(struct kref *kref) ...@@ -171,6 +172,7 @@ static void drm_master_destroy(struct kref *kref)
drm_ht_remove(&master->magiclist); drm_ht_remove(&master->magiclist);
mutex_unlock(&dev->struct_mutex);
kfree(master); kfree(master);
} }
...@@ -186,19 +188,20 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data, ...@@ -186,19 +188,20 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
{ {
int ret = 0; int ret = 0;
mutex_lock(&dev->master_mutex);
if (file_priv->is_master) if (file_priv->is_master)
return 0; goto out_unlock;
if (file_priv->minor->master && file_priv->minor->master != file_priv->master) if (file_priv->minor->master) {
return -EINVAL; ret = -EINVAL;
goto out_unlock;
if (!file_priv->master) }
return -EINVAL;
if (file_priv->minor->master) if (!file_priv->master) {
return -EINVAL; ret = -EINVAL;
goto out_unlock;
}
mutex_lock(&dev->struct_mutex);
file_priv->minor->master = drm_master_get(file_priv->master); file_priv->minor->master = drm_master_get(file_priv->master);
file_priv->is_master = 1; file_priv->is_master = 1;
if (dev->driver->master_set) { if (dev->driver->master_set) {
...@@ -208,27 +211,33 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data, ...@@ -208,27 +211,33 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
drm_master_put(&file_priv->minor->master); drm_master_put(&file_priv->minor->master);
} }
} }
mutex_unlock(&dev->struct_mutex);
out_unlock:
mutex_unlock(&dev->master_mutex);
return ret; return ret;
} }
int drm_dropmaster_ioctl(struct drm_device *dev, void *data, int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv) struct drm_file *file_priv)
{ {
int ret = -EINVAL;
mutex_lock(&dev->master_mutex);
if (!file_priv->is_master) if (!file_priv->is_master)
return -EINVAL; goto out_unlock;
if (!file_priv->minor->master) if (!file_priv->minor->master)
return -EINVAL; goto out_unlock;
mutex_lock(&dev->struct_mutex); ret = 0;
if (dev->driver->master_drop) if (dev->driver->master_drop)
dev->driver->master_drop(dev, file_priv, false); dev->driver->master_drop(dev, file_priv, false);
drm_master_put(&file_priv->minor->master); drm_master_put(&file_priv->minor->master);
file_priv->is_master = 0; file_priv->is_master = 0;
mutex_unlock(&dev->struct_mutex);
return 0; out_unlock:
mutex_unlock(&dev->master_mutex);
return ret;
} }
/* /*
...@@ -559,6 +568,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver, ...@@ -559,6 +568,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
spin_lock_init(&dev->event_lock); spin_lock_init(&dev->event_lock);
mutex_init(&dev->struct_mutex); mutex_init(&dev->struct_mutex);
mutex_init(&dev->ctxlist_mutex); mutex_init(&dev->ctxlist_mutex);
mutex_init(&dev->master_mutex);
dev->anon_inode = drm_fs_inode_new(); dev->anon_inode = drm_fs_inode_new();
if (IS_ERR(dev->anon_inode)) { if (IS_ERR(dev->anon_inode)) {
...@@ -612,6 +622,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver, ...@@ -612,6 +622,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
drm_minor_free(dev, DRM_MINOR_CONTROL); drm_minor_free(dev, DRM_MINOR_CONTROL);
drm_fs_inode_free(dev->anon_inode); drm_fs_inode_free(dev->anon_inode);
err_free: err_free:
mutex_destroy(&dev->master_mutex);
kfree(dev); kfree(dev);
return NULL; return NULL;
} }
...@@ -633,6 +644,8 @@ static void drm_dev_release(struct kref *ref) ...@@ -633,6 +644,8 @@ static void drm_dev_release(struct kref *ref)
drm_minor_free(dev, DRM_MINOR_CONTROL); drm_minor_free(dev, DRM_MINOR_CONTROL);
kfree(dev->devname); kfree(dev->devname);
mutex_destroy(&dev->master_mutex);
kfree(dev); kfree(dev);
} }
......
...@@ -405,7 +405,8 @@ struct drm_prime_file_private { ...@@ -405,7 +405,8 @@ struct drm_prime_file_private {
struct drm_file { struct drm_file {
unsigned always_authenticated :1; unsigned always_authenticated :1;
unsigned authenticated :1; unsigned authenticated :1;
unsigned is_master :1; /* this file private is a master for a minor */ /* Whether we're master for a minor. Protected by master_mutex */
unsigned is_master :1;
/* true when the client has asked us to expose stereo 3D mode flags */ /* true when the client has asked us to expose stereo 3D mode flags */
unsigned stereo_allowed :1; unsigned stereo_allowed :1;
...@@ -684,28 +685,29 @@ struct drm_gem_object { ...@@ -684,28 +685,29 @@ struct drm_gem_object {
#include <drm/drm_crtc.h> #include <drm/drm_crtc.h>
/* per-master structure */ /**
* struct drm_master - drm master structure
*
* @refcount: Refcount for this master object.
* @minor: Link back to minor char device we are master for. Immutable.
* @unique: Unique identifier: e.g. busid. Protected by drm_global_mutex.
* @unique_len: Length of unique field. Protected by drm_global_mutex.
* @unique_size: Amount allocated. Protected by drm_global_mutex.
* @magiclist: Hash of used authentication tokens. Protected by struct_mutex.
* @magicfree: List of used authentication tokens. Protected by struct_mutex.
* @lock: DRI lock information.
* @driver_priv: Pointer to driver-private information.
*/
struct drm_master { struct drm_master {
struct kref refcount;
struct kref refcount; /* refcount for this master */ struct drm_minor *minor;
char *unique;
struct drm_minor *minor; /**< link back to minor we are a master for */ int unique_len;
int unique_size;
char *unique; /**< Unique identifier: e.g., busid */
int unique_len; /**< Length of unique field */
int unique_size; /**< amount allocated */
int blocked; /**< Blocked due to VC switch? */
/** \name Authentication */
/*@{ */
struct drm_open_hash magiclist; struct drm_open_hash magiclist;
struct list_head magicfree; struct list_head magicfree;
/*@} */ struct drm_lock_data lock;
void *driver_priv;
struct drm_lock_data lock; /**< Information on hardware lock */
void *driver_priv; /**< Private structure for driver to use */
}; };
/* Size of ringbuffer for vblank timestamps. Just double-buffer /* Size of ringbuffer for vblank timestamps. Just double-buffer
...@@ -1020,7 +1022,8 @@ struct drm_minor { ...@@ -1020,7 +1022,8 @@ struct drm_minor {
struct list_head debugfs_list; struct list_head debugfs_list;
struct mutex debugfs_lock; /* Protects debugfs_list. */ struct mutex debugfs_lock; /* Protects debugfs_list. */
struct drm_master *master; /* currently active master for this node */ /* currently active master for this node. Protected by master_mutex */
struct drm_master *master;
struct drm_mode_group mode_group; struct drm_mode_group mode_group;
}; };
...@@ -1070,6 +1073,7 @@ struct drm_device { ...@@ -1070,6 +1073,7 @@ struct drm_device {
/*@{ */ /*@{ */
spinlock_t count_lock; /**< For inuse, drm_device::open_count, drm_device::buf_use */ spinlock_t count_lock; /**< For inuse, drm_device::open_count, drm_device::buf_use */
struct mutex struct_mutex; /**< For others */ struct mutex struct_mutex; /**< For others */
struct mutex master_mutex; /**< For drm_minor::master and drm_file::is_master */
/*@} */ /*@} */
/** \name Usage Counters */ /** \name Usage Counters */
......
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