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 /*
 114  * drm_new_set_master - Allocate a new master object and become master for the
 115  * associated master realm.
 116  *
 117  * @dev: The associated device.
 118  * @fpriv: File private identifying the client.
 119  *
 120  * This function must be called with dev::master_mutex held.
 121  * Returns negative error code on failure. Zero on success.
 122  */
 123 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
 124 {
 125         struct drm_master *old_master;
 126         int ret;
 127
 128         lockdep_assert_held_once(&dev->master_mutex);
 129
 130         /* create a new master */
 131         fpriv->minor->master = drm_master_create(fpriv->minor->dev);
 132         if (!fpriv->minor->master)
 133                 return -ENOMEM;
 134
 135         /* take another reference for the copy in the local file priv */
 136         old_master = fpriv->master;
 137         fpriv->master = drm_master_get(fpriv->minor->master);
 138
 139         if (dev->driver->master_create) {
 140                 ret = dev->driver->master_create(dev, fpriv->master);
 141                 if (ret)
 142                         goto out_err;
 143         }
 144         if (dev->driver->master_set) {
 145                 ret = dev->driver->master_set(dev, fpriv, true);
 146                 if (ret)
 147                         goto out_err;
 148         }
 149
 150         fpriv->is_master = 1;
 151         fpriv->allowed_master = 1;
 152         fpriv->authenticated = 1;
 153         if (old_master)
 154                 drm_master_put(&old_master);
 155
 156         return 0;
 157
 158 out_err:
 159         /* drop both references and restore old master on failure */
 160         drm_master_put(&fpriv->minor->master);
 161         drm_master_put(&fpriv->master);
 162         fpriv->master = old_master;
 163
 164         return ret;
 165 }
 166
 167 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 168                         struct drm_file *file_priv)
 169 {
 170         int ret = 0;
 171
 172         mutex_lock(&dev->master_mutex);
 173         if (file_priv->is_master)
 174                 goto out_unlock;
 175
 176         if (file_priv->minor->master) {
 177                 ret = -EINVAL;
 178                 goto out_unlock;
 179         }
 180
 181         if (!file_priv->master) {
 182                 ret = -EINVAL;
 183                 goto out_unlock;
 184         }
 185
 186         if (!file_priv->allowed_master) {
 187                 ret = drm_new_set_master(dev, file_priv);
 188                 goto out_unlock;
 189         }
 190
 191         file_priv->minor->master = drm_master_get(file_priv->master);
 192         file_priv->is_master = 1;
 193         if (dev->driver->master_set) {
 194                 ret = dev->driver->master_set(dev, file_priv, false);
 195                 if (unlikely(ret != 0)) {
 196                         file_priv->is_master = 0;
 197                         drm_master_put(&file_priv->minor->master);
 198                 }
 199         }
 200
 201 out_unlock:
 202         mutex_unlock(&dev->master_mutex);
 203         return ret;
 204 }
 205
 206 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 207                          struct drm_file *file_priv)
 208 {
 209         int ret = -EINVAL;
 210
 211         mutex_lock(&dev->master_mutex);
 212         if (!file_priv->is_master)
 213                 goto out_unlock;
 214
 215         if (!file_priv->minor->master)
 216                 goto out_unlock;
 217
 218         ret = 0;
 219         if (dev->driver->master_drop)
 220                 dev->driver->master_drop(dev, file_priv, false);
 221         drm_master_put(&file_priv->minor->master);
 222         file_priv->is_master = 0;
 223
 224 out_unlock:
 225         mutex_unlock(&dev->master_mutex);
 226         return ret;
 227 }
 228
 229 int drm_master_open(struct drm_file *file_priv)
 230 {
 231         struct drm_device *dev = file_priv->minor->dev;
 232         int ret = 0;
 233
 234         /* if there is no current master make this fd it, but do not create
 235          * any master object for render clients */
 236         mutex_lock(&dev->master_mutex);
 237         if (!file_priv->minor->master)
 238                 ret = drm_new_set_master(dev, file_priv);
 239         else
 240                 file_priv->master = drm_master_get(file_priv->minor->master);
 241         mutex_unlock(&dev->master_mutex);
 242
 243         return ret;
 244 }
 245
 246 void drm_master_release(struct drm_file *file_priv)
 247 {
 248         struct drm_device *dev = file_priv->minor->dev;
 249         struct drm_master *master = file_priv->master;
 250
 251         mutex_lock(&dev->master_mutex);
 252         if (file_priv->magic)
 253                 idr_remove(&file_priv->master->magic_map, file_priv->magic);
 254
 255         if (!file_priv->is_master)
 256                 goto out;
 257
 258         if (!drm_core_check_feature(dev, DRIVER_MODESET)) {
 259                 /*
 260                  * Since the master is disappearing, so is the
 261                  * possibility to lock.
 262                  */
 263                 mutex_lock(&dev->struct_mutex);
 264                 if (master->lock.hw_lock) {
 265                         if (dev->sigdata.lock == master->lock.hw_lock)
 266                                 dev->sigdata.lock = NULL;
 267                         master->lock.hw_lock = NULL;
 268                         master->lock.file_priv = NULL;
 269                         wake_up_interruptible_all(&master->lock.lock_queue);
 270                 }
 271                 mutex_unlock(&dev->struct_mutex);
 272         }
 273
 274         if (file_priv->minor->master == file_priv->master) {
 275                 /* drop the reference held my the minor */
 276                 if (dev->driver->master_drop)
 277                         dev->driver->master_drop(dev, file_priv, true);
 278                 drm_master_put(&file_priv->minor->master);
 279         }
 280 out:
 281         /* drop the master reference held by the file priv */
 282         if (file_priv->master)
 283                 drm_master_put(&file_priv->master);
 284         file_priv->is_master = 0;
 285         mutex_unlock(&dev->master_mutex);
 286 }
 287
 288 struct drm_master *drm_master_get(struct drm_master *master)
 289 {
 290         kref_get(&master->refcount);
 291         return master;
 292 }
 293 EXPORT_SYMBOL(drm_master_get);
 294
 295 static void drm_master_destroy(struct kref *kref)
 296 {
 297         struct drm_master *master = container_of(kref, struct drm_master, refcount);
 298         struct drm_device *dev = master->dev;
 299
 300         if (dev->driver->master_destroy)
 301                 dev->driver->master_destroy(dev, master);
 302
 303         drm_legacy_master_rmmaps(dev, master);
 304
 305         idr_destroy(&master->magic_map);
 306         kfree(master->unique);
 307         kfree(master);
 308 }
 309
 310 void drm_master_put(struct drm_master **master)
 311 {
 312         kref_put(&(*master)->refcount, drm_master_destroy);
 313         *master = NULL;
 314 }
 315 EXPORT_SYMBOL(drm_master_put);