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1/**
2 * \file drm_auth.c
3 * IOCTLs for authentication
4 *
5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
7 */
8
9/*
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
11 *
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
22 *
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
34 */
35
36#include "drmP.h"
37
38/**
39 * Find the file with the given magic number.
40 *
41 * \param dev DRM device.
42 * \param magic magic number.
43 *
44 * Searches in drm_device::magiclist within all files with the same hash key
45 * the one with matching magic number, while holding the drm_device::struct_mutex
46 * lock.
47 */
48static struct drm_file *drm_find_file(struct drm_master *master, drm_magic_t magic)
49{
50 struct drm_file *retval = NULL;
51 struct drm_magic_entry *pt;
52 struct drm_hash_item *hash;
53 struct drm_device *dev = master->minor->dev;
54
55 mutex_lock(&dev->struct_mutex);
56 if (!drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
57 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
58 retval = pt->priv;
59 }
60 mutex_unlock(&dev->struct_mutex);
61 return retval;
62}
63
64/**
65 * Adds a magic number.
66 *
67 * \param dev DRM device.
68 * \param priv file private data.
69 * \param magic magic number.
70 *
71 * Creates a drm_magic_entry structure and appends to the linked list
72 * associated the magic number hash key in drm_device::magiclist, while holding
73 * the drm_device::struct_mutex lock.
74 */
75static int drm_add_magic(struct drm_master *master, struct drm_file *priv,
76 drm_magic_t magic)
77{
78 struct drm_magic_entry *entry;
79 struct drm_device *dev = master->minor->dev;
80 DRM_DEBUG("%d\n", magic);
81
82 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
83 if (!entry)
84 return -ENOMEM;
85 entry->priv = priv;
86 entry->hash_item.key = (unsigned long)magic;
87 mutex_lock(&dev->struct_mutex);
88 drm_ht_insert_item(&master->magiclist, &entry->hash_item);
89 list_add_tail(&entry->head, &master->magicfree);
90 mutex_unlock(&dev->struct_mutex);
91
92 return 0;
93}
94
95/**
96 * Remove a magic number.
97 *
98 * \param dev DRM device.
99 * \param magic magic number.
100 *
101 * Searches and unlinks the entry in drm_device::magiclist with the magic
102 * number hash key, while holding the drm_device::struct_mutex lock.
103 */
104static int drm_remove_magic(struct drm_master *master, drm_magic_t magic)
105{
106 struct drm_magic_entry *pt;
107 struct drm_hash_item *hash;
108 struct drm_device *dev = master->minor->dev;
109
110 DRM_DEBUG("%d\n", magic);
111
112 mutex_lock(&dev->struct_mutex);
113 if (drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
114 mutex_unlock(&dev->struct_mutex);
115 return -EINVAL;
116 }
117 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
118 drm_ht_remove_item(&master->magiclist, hash);
119 list_del(&pt->head);
120 mutex_unlock(&dev->struct_mutex);
121
122 kfree(pt);
123
124 return 0;
125}
126
127/**
128 * Get a unique magic number (ioctl).
129 *
130 * \param inode device inode.
131 * \param file_priv DRM file private.
132 * \param cmd command.
133 * \param arg pointer to a resulting drm_auth structure.
134 * \return zero on success, or a negative number on failure.
135 *
136 * If there is a magic number in drm_file::magic then use it, otherwise
137 * searches an unique non-zero magic number and add it associating it with \p
138 * file_priv.
139 */
140int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
141{
142 static drm_magic_t sequence = 0;
143 static DEFINE_SPINLOCK(lock);
144 struct drm_auth *auth = data;
145
146 /* Find unique magic */
147 if (file_priv->magic) {
148 auth->magic = file_priv->magic;
149 } else {
150 do {
151 spin_lock(&lock);
152 if (!sequence)
153 ++sequence; /* reserve 0 */
154 auth->magic = sequence++;
155 spin_unlock(&lock);
156 } while (drm_find_file(file_priv->master, auth->magic));
157 file_priv->magic = auth->magic;
158 drm_add_magic(file_priv->master, file_priv, auth->magic);
159 }
160
161 DRM_DEBUG("%u\n", auth->magic);
162
163 return 0;
164}
165
166/**
167 * Authenticate with a magic.
168 *
169 * \param inode device inode.
170 * \param file_priv DRM file private.
171 * \param cmd command.
172 * \param arg pointer to a drm_auth structure.
173 * \return zero if authentication successed, or a negative number otherwise.
174 *
175 * Checks if \p file_priv is associated with the magic number passed in \arg.
176 */
177int drm_authmagic(struct drm_device *dev, void *data,
178 struct drm_file *file_priv)
179{
180 struct drm_auth *auth = data;
181 struct drm_file *file;
182
183 DRM_DEBUG("%u\n", auth->magic);
184 if ((file = drm_find_file(file_priv->master, auth->magic))) {
185 file->authenticated = 1;
186 drm_remove_magic(file_priv->master, auth->magic);
187 return 0;
188 }
189 return -EINVAL;
190}
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#include <drm/drm_lease.h>
35
36/**
37 * DOC: master and authentication
38 *
39 * &struct drm_master is used to track groups of clients with open
40 * primary/legacy device nodes. For every &struct drm_file which has had at
41 * least once successfully became the device master (either through the
42 * SET_MASTER IOCTL, or implicitly through opening the primary device node when
43 * no one else is the current master that time) there exists one &drm_master.
44 * This is noted in &drm_file.is_master. All other clients have just a pointer
45 * to the &drm_master they are associated with.
46 *
47 * In addition only one &drm_master can be the current master for a &drm_device.
48 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
49 * implicitly through closing/openeing the primary device node. See also
50 * drm_is_current_master().
51 *
52 * Clients can authenticate against the current master (if it matches their own)
53 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
54 * this allows controlled access to the device for an entire group of mutually
55 * trusted clients.
56 */
57
58int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
59{
60 struct drm_auth *auth = data;
61 int ret = 0;
62
63 mutex_lock(&dev->master_mutex);
64 if (!file_priv->magic) {
65 ret = idr_alloc(&file_priv->master->magic_map, file_priv,
66 1, 0, GFP_KERNEL);
67 if (ret >= 0)
68 file_priv->magic = ret;
69 }
70 auth->magic = file_priv->magic;
71 mutex_unlock(&dev->master_mutex);
72
73 DRM_DEBUG("%u\n", auth->magic);
74
75 return ret < 0 ? ret : 0;
76}
77
78int drm_authmagic(struct drm_device *dev, void *data,
79 struct drm_file *file_priv)
80{
81 struct drm_auth *auth = data;
82 struct drm_file *file;
83
84 DRM_DEBUG("%u\n", auth->magic);
85
86 mutex_lock(&dev->master_mutex);
87 file = idr_find(&file_priv->master->magic_map, auth->magic);
88 if (file) {
89 file->authenticated = 1;
90 idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
91 }
92 mutex_unlock(&dev->master_mutex);
93
94 return file ? 0 : -EINVAL;
95}
96
97struct drm_master *drm_master_create(struct drm_device *dev)
98{
99 struct drm_master *master;
100
101 master = kzalloc(sizeof(*master), GFP_KERNEL);
102 if (!master)
103 return NULL;
104
105 kref_init(&master->refcount);
106 spin_lock_init(&master->lock.spinlock);
107 init_waitqueue_head(&master->lock.lock_queue);
108 idr_init(&master->magic_map);
109 master->dev = dev;
110
111 /* initialize the tree of output resource lessees */
112 master->lessor = NULL;
113 master->lessee_id = 0;
114 INIT_LIST_HEAD(&master->lessees);
115 INIT_LIST_HEAD(&master->lessee_list);
116 idr_init(&master->leases);
117 idr_init(&master->lessee_idr);
118
119 return master;
120}
121
122static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
123 bool new_master)
124{
125 int ret = 0;
126
127 dev->master = drm_master_get(fpriv->master);
128 if (dev->driver->master_set) {
129 ret = dev->driver->master_set(dev, fpriv, new_master);
130 if (unlikely(ret != 0)) {
131 drm_master_put(&dev->master);
132 }
133 }
134
135 return ret;
136}
137
138static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
139{
140 struct drm_master *old_master;
141 int ret;
142
143 lockdep_assert_held_once(&dev->master_mutex);
144
145 old_master = fpriv->master;
146 fpriv->master = drm_master_create(dev);
147 if (!fpriv->master) {
148 fpriv->master = old_master;
149 return -ENOMEM;
150 }
151
152 if (dev->driver->master_create) {
153 ret = dev->driver->master_create(dev, fpriv->master);
154 if (ret)
155 goto out_err;
156 }
157 fpriv->is_master = 1;
158 fpriv->authenticated = 1;
159
160 ret = drm_set_master(dev, fpriv, true);
161 if (ret)
162 goto out_err;
163
164 if (old_master)
165 drm_master_put(&old_master);
166
167 return 0;
168
169out_err:
170 /* drop references and restore old master on failure */
171 drm_master_put(&fpriv->master);
172 fpriv->master = old_master;
173
174 return ret;
175}
176
177int drm_setmaster_ioctl(struct drm_device *dev, void *data,
178 struct drm_file *file_priv)
179{
180 int ret = 0;
181
182 mutex_lock(&dev->master_mutex);
183 if (drm_is_current_master(file_priv))
184 goto out_unlock;
185
186 if (dev->master) {
187 ret = -EINVAL;
188 goto out_unlock;
189 }
190
191 if (!file_priv->master) {
192 ret = -EINVAL;
193 goto out_unlock;
194 }
195
196 if (!file_priv->is_master) {
197 ret = drm_new_set_master(dev, file_priv);
198 goto out_unlock;
199 }
200
201 if (file_priv->master->lessor != NULL) {
202 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id);
203 ret = -EINVAL;
204 goto out_unlock;
205 }
206
207 ret = drm_set_master(dev, file_priv, false);
208out_unlock:
209 mutex_unlock(&dev->master_mutex);
210 return ret;
211}
212
213static void drm_drop_master(struct drm_device *dev,
214 struct drm_file *fpriv)
215{
216 if (dev->driver->master_drop)
217 dev->driver->master_drop(dev, fpriv);
218 drm_master_put(&dev->master);
219}
220
221int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
222 struct drm_file *file_priv)
223{
224 int ret = -EINVAL;
225
226 mutex_lock(&dev->master_mutex);
227 if (!drm_is_current_master(file_priv))
228 goto out_unlock;
229
230 if (!dev->master)
231 goto out_unlock;
232
233 if (file_priv->master->lessor != NULL) {
234 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
235 ret = -EINVAL;
236 goto out_unlock;
237 }
238
239 ret = 0;
240 drm_drop_master(dev, file_priv);
241out_unlock:
242 mutex_unlock(&dev->master_mutex);
243 return ret;
244}
245
246int drm_master_open(struct drm_file *file_priv)
247{
248 struct drm_device *dev = file_priv->minor->dev;
249 int ret = 0;
250
251 /* if there is no current master make this fd it, but do not create
252 * any master object for render clients */
253 mutex_lock(&dev->master_mutex);
254 if (!dev->master)
255 ret = drm_new_set_master(dev, file_priv);
256 else
257 file_priv->master = drm_master_get(dev->master);
258 mutex_unlock(&dev->master_mutex);
259
260 return ret;
261}
262
263void drm_master_release(struct drm_file *file_priv)
264{
265 struct drm_device *dev = file_priv->minor->dev;
266 struct drm_master *master = file_priv->master;
267
268 mutex_lock(&dev->master_mutex);
269 if (file_priv->magic)
270 idr_remove(&file_priv->master->magic_map, file_priv->magic);
271
272 if (!drm_is_current_master(file_priv))
273 goto out;
274
275 if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
276 /*
277 * Since the master is disappearing, so is the
278 * possibility to lock.
279 */
280 mutex_lock(&dev->struct_mutex);
281 if (master->lock.hw_lock) {
282 if (dev->sigdata.lock == master->lock.hw_lock)
283 dev->sigdata.lock = NULL;
284 master->lock.hw_lock = NULL;
285 master->lock.file_priv = NULL;
286 wake_up_interruptible_all(&master->lock.lock_queue);
287 }
288 mutex_unlock(&dev->struct_mutex);
289 }
290
291 if (dev->master == file_priv->master)
292 drm_drop_master(dev, file_priv);
293out:
294 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) {
295 /* Revoke any leases held by this or lessees, but only if
296 * this is the "real" master
297 */
298 drm_lease_revoke(master);
299 }
300
301 /* drop the master reference held by the file priv */
302 if (file_priv->master)
303 drm_master_put(&file_priv->master);
304 mutex_unlock(&dev->master_mutex);
305}
306
307/**
308 * drm_is_current_master - checks whether @priv is the current master
309 * @fpriv: DRM file private
310 *
311 * Checks whether @fpriv is current master on its device. This decides whether a
312 * client is allowed to run DRM_MASTER IOCTLs.
313 *
314 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
315 * - the current master is assumed to own the non-shareable display hardware.
316 */
317bool drm_is_current_master(struct drm_file *fpriv)
318{
319 return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
320}
321EXPORT_SYMBOL(drm_is_current_master);
322
323/**
324 * drm_master_get - reference a master pointer
325 * @master: &struct drm_master
326 *
327 * Increments the reference count of @master and returns a pointer to @master.
328 */
329struct drm_master *drm_master_get(struct drm_master *master)
330{
331 kref_get(&master->refcount);
332 return master;
333}
334EXPORT_SYMBOL(drm_master_get);
335
336static void drm_master_destroy(struct kref *kref)
337{
338 struct drm_master *master = container_of(kref, struct drm_master, refcount);
339 struct drm_device *dev = master->dev;
340
341 if (drm_core_check_feature(dev, DRIVER_MODESET))
342 drm_lease_destroy(master);
343
344 if (dev->driver->master_destroy)
345 dev->driver->master_destroy(dev, master);
346
347 drm_legacy_master_rmmaps(dev, master);
348
349 idr_destroy(&master->magic_map);
350 idr_destroy(&master->leases);
351 idr_destroy(&master->lessee_idr);
352
353 kfree(master->unique);
354 kfree(master);
355}
356
357/**
358 * drm_master_put - unreference and clear a master pointer
359 * @master: pointer to a pointer of &struct drm_master
360 *
361 * This decrements the &drm_master behind @master and sets it to NULL.
362 */
363void drm_master_put(struct drm_master **master)
364{
365 kref_put(&(*master)->refcount, drm_master_destroy);
366 *master = NULL;
367}
368EXPORT_SYMBOL(drm_master_put);