drivers/gpu/drm/drm_auth.c

   1 /*
   2  * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
   3  *
   4  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   5  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
   6  * All Rights Reserved.
   7  *
   8  * Author Rickard E. (Rik) Faith <faith@valinux.com>
   9  * Author Gareth Hughes <gareth@valinux.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a
  12  * copy of this software and associated documentation files (the "Software"),
  13  * to deal in the Software without restriction, including without limitation
  14  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  15  * and/or sell copies of the Software, and to permit persons to whom the
  16  * Software is furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice (including the next
  19  * paragraph) shall be included in all copies or substantial portions of the
  20  * Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  25  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  26  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  27  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  28  * OTHER DEALINGS IN THE SOFTWARE.
  29  */
  30
  31 #include <drm/drmP.h>
  32 #include "drm_internal.h"
  33 #include "drm_legacy.h"
  34
  35 /**
  36  * drm_getmagic - Get unique magic of a client
  37  * @dev: DRM device to operate on
  38  * @data: ioctl data containing the drm_auth object
  39  * @file_priv: DRM file that performs the operation
  40  *
  41  * This looks up the unique magic of the passed client and returns it. If the
  42  * client did not have a magic assigned, yet, a new one is registered. The magic
  43  * is stored in the passed drm_auth object.
  44  *
  45  * Returns: 0 on success, negative error code on failure.
  46  */
  47 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
  48 {
  49         struct drm_auth *auth = data;
  50         int ret = 0;
  51
  52         mutex_lock(&dev->master_mutex);
  53         if (!file_priv->magic) {
  54                 ret = idr_alloc(&file_priv->master->magic_map, file_priv,
  55                                 1, 0, GFP_KERNEL);
  56                 if (ret >= 0)
  57                         file_priv->magic = ret;
  58         }
  59         auth->magic = file_priv->magic;
  60         mutex_unlock(&dev->master_mutex);
  61
  62         DRM_DEBUG("%u\n", auth->magic);
  63
  64         return ret < 0 ? ret : 0;
  65 }
  66
  67 /**
  68  * drm_authmagic - Authenticate client with a magic
  69  * @dev: DRM device to operate on
  70  * @data: ioctl data containing the drm_auth object
  71  * @file_priv: DRM file that performs the operation
  72  *
  73  * This looks up a DRM client by the passed magic and authenticates it.
  74  *
  75  * Returns: 0 on success, negative error code on failure.
  76  */
  77 int drm_authmagic(struct drm_device *dev, void *data,
  78                   struct drm_file *file_priv)
  79 {
  80         struct drm_auth *auth = data;
  81         struct drm_file *file;
  82
  83         DRM_DEBUG("%u\n", auth->magic);
  84
  85         mutex_lock(&dev->master_mutex);
  86         file = idr_find(&file_priv->master->magic_map, auth->magic);
  87         if (file) {
  88                 file->authenticated = 1;
  89                 idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
  90         }
  91         mutex_unlock(&dev->master_mutex);
  92
  93         return file ? 0 : -EINVAL;
  94 }
  95
  96 static struct drm_master *drm_master_create(struct drm_device *dev)
  97 {
  98         struct drm_master *master;
  99
 100         master = kzalloc(sizeof(*master), GFP_KERNEL);
 101         if (!master)
 102                 return NULL;
 103
 104         kref_init(&master->refcount);
 105         spin_lock_init(&master->lock.spinlock);
 106         init_waitqueue_head(&master->lock.lock_queue);
 107         idr_init(&master->magic_map);
 108         master->dev = dev;
 109
 110         return master;
 111 }
 112
 113 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
 114                           bool new_master)
 115 {
 116         int ret = 0;
 117
 118         dev->master = drm_master_get(fpriv->master);
 119         fpriv->is_master = 1;
 120         if (dev->driver->master_set) {
 121                 ret = dev->driver->master_set(dev, fpriv, new_master);
 122                 if (unlikely(ret != 0)) {
 123                         fpriv->is_master = 0;
 124                         drm_master_put(&dev->master);
 125                 }
 126         }
 127
 128         return ret;
 129 }
 130
 131 /*
 132  * drm_new_set_master - Allocate a new master object and become master for the
 133  * associated master realm.
 134  *
 135  * @dev: The associated device.
 136  * @fpriv: File private identifying the client.
 137  *
 138  * This function must be called with dev::master_mutex held.
 139  * Returns negative error code on failure. Zero on success.
 140  */
 141 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
 142 {
 143         struct drm_master *old_master;
 144         int ret;
 145
 146         lockdep_assert_held_once(&dev->master_mutex);
 147
 148         old_master = fpriv->master;
 149         fpriv->master = drm_master_create(dev);
 150         if (!fpriv->master) {
 151                 fpriv->master = old_master;
 152                 return -ENOMEM;
 153         }
 154
 155         if (dev->driver->master_create) {
 156                 ret = dev->driver->master_create(dev, fpriv->master);
 157                 if (ret)
 158                         goto out_err;
 159         }
 160         fpriv->allowed_master = 1;
 161         fpriv->authenticated = 1;
 162
 163         ret = drm_set_master(dev, fpriv, true);
 164         if (ret)
 165                 goto out_err;
 166
 167         if (old_master)
 168                 drm_master_put(&old_master);
 169
 170         return 0;
 171
 172 out_err:
 173         /* drop references and restore old master on failure */
 174         drm_master_put(&fpriv->master);
 175         fpriv->master = old_master;
 176
 177         return ret;
 178 }
 179
 180 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 181                         struct drm_file *file_priv)
 182 {
 183         int ret = 0;
 184
 185         mutex_lock(&dev->master_mutex);
 186         if (drm_is_current_master(file_priv))
 187                 goto out_unlock;
 188
 189         if (dev->master) {
 190                 ret = -EINVAL;
 191                 goto out_unlock;
 192         }
 193
 194         if (!file_priv->master) {
 195                 ret = -EINVAL;
 196                 goto out_unlock;
 197         }
 198
 199         if (!file_priv->allowed_master) {
 200                 ret = drm_new_set_master(dev, file_priv);
 201                 goto out_unlock;
 202         }
 203
 204         ret = drm_set_master(dev, file_priv, false);
 205 out_unlock:
 206         mutex_unlock(&dev->master_mutex);
 207         return ret;
 208 }
 209
 210 static void drm_drop_master(struct drm_device *dev,
 211                             struct drm_file *fpriv)
 212 {
 213         if (dev->driver->master_drop)
 214                 dev->driver->master_drop(dev, fpriv);
 215         drm_master_put(&dev->master);
 216         fpriv->is_master = 0;
 217 }
 218
 219 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 220                          struct drm_file *file_priv)
 221 {
 222         int ret = -EINVAL;
 223
 224         mutex_lock(&dev->master_mutex);
 225         if (!drm_is_current_master(file_priv))
 226                 goto out_unlock;
 227
 228         if (!dev->master)
 229                 goto out_unlock;
 230
 231         ret = 0;
 232         drm_drop_master(dev, file_priv);
 233 out_unlock:
 234         mutex_unlock(&dev->master_mutex);
 235         return ret;
 236 }
 237
 238 int drm_master_open(struct drm_file *file_priv)
 239 {
 240         struct drm_device *dev = file_priv->minor->dev;
 241         int ret = 0;
 242
 243         /* if there is no current master make this fd it, but do not create
 244          * any master object for render clients */
 245         mutex_lock(&dev->master_mutex);
 246         if (!dev->master)
 247                 ret = drm_new_set_master(dev, file_priv);
 248         else
 249                 file_priv->master = drm_master_get(dev->master);
 250         mutex_unlock(&dev->master_mutex);
 251
 252         return ret;
 253 }
 254
 255 void drm_master_release(struct drm_file *file_priv)
 256 {
 257         struct drm_device *dev = file_priv->minor->dev;
 258         struct drm_master *master = file_priv->master;
 259
 260         mutex_lock(&dev->master_mutex);
 261         if (file_priv->magic)
 262                 idr_remove(&file_priv->master->magic_map, file_priv->magic);
 263
 264         if (!drm_is_current_master(file_priv))
 265                 goto out;
 266
 267         if (!drm_core_check_feature(dev, DRIVER_MODESET)) {
 268                 /*
 269                  * Since the master is disappearing, so is the
 270                  * possibility to lock.
 271                  */
 272                 mutex_lock(&dev->struct_mutex);
 273                 if (master->lock.hw_lock) {
 274                         if (dev->sigdata.lock == master->lock.hw_lock)
 275                                 dev->sigdata.lock = NULL;
 276                         master->lock.hw_lock = NULL;
 277                         master->lock.file_priv = NULL;
 278                         wake_up_interruptible_all(&master->lock.lock_queue);
 279                 }
 280                 mutex_unlock(&dev->struct_mutex);
 281         }
 282
 283         if (dev->master == file_priv->master)
 284                 drm_drop_master(dev, file_priv);
 285 out:
 286         /* drop the master reference held by the file priv */
 287         if (file_priv->master)
 288                 drm_master_put(&file_priv->master);
 289         mutex_unlock(&dev->master_mutex);
 290 }
 291
 292 bool drm_is_current_master(struct drm_file *fpriv)
 293 {
 294         return fpriv->is_master;
 295 }
 296 EXPORT_SYMBOL(drm_is_current_master);
 297
 298 struct drm_master *drm_master_get(struct drm_master *master)
 299 {
 300         kref_get(&master->refcount);
 301         return master;
 302 }
 303 EXPORT_SYMBOL(drm_master_get);
 304
 305 static void drm_master_destroy(struct kref *kref)
 306 {
 307         struct drm_master *master = container_of(kref, struct drm_master, refcount);
 308         struct drm_device *dev = master->dev;
 309
 310         if (dev->driver->master_destroy)
 311                 dev->driver->master_destroy(dev, master);
 312
 313         drm_legacy_master_rmmaps(dev, master);
 314
 315         idr_destroy(&master->magic_map);
 316         kfree(master->unique);
 317         kfree(master);
 318 }
 319
 320 void drm_master_put(struct drm_master **master)
 321 {
 322         kref_put(&(*master)->refcount, drm_master_destroy);
 323         *master = NULL;
 324 }
 325 EXPORT_SYMBOL(drm_master_put);