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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
35/**
36 * DOC: master and authentication
37 *
38 * struct &drm_master is used to track groups of clients with open
39 * primary/legacy device nodes. For every struct &drm_file which has had at
40 * least once successfully became the device master (either through the
41 * SET_MASTER IOCTL, or implicitly through opening the primary device node when
42 * no one else is the current master that time) there exists one &drm_master.
43 * This is noted in the is_master member of &drm_file. All other clients have
44 * just a pointer to the &drm_master they are associated with.
45 *
46 * In addition only one &drm_master can be the current master for a &drm_device.
47 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
48 * implicitly through closing/openeing the primary device node. See also
49 * drm_is_current_master().
50 *
51 * Clients can authenticate against the current master (if it matches their own)
52 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
53 * this allows controlled access to the device for an entire group of mutually
54 * trusted clients.
55 */
56
57int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
58{
59 struct drm_auth *auth = data;
60 int ret = 0;
61
62 mutex_lock(&dev->master_mutex);
63 if (!file_priv->magic) {
64 ret = idr_alloc(&file_priv->master->magic_map, file_priv,
65 1, 0, GFP_KERNEL);
66 if (ret >= 0)
67 file_priv->magic = ret;
68 }
69 auth->magic = file_priv->magic;
70 mutex_unlock(&dev->master_mutex);
71
72 DRM_DEBUG("%u\n", auth->magic);
73
74 return ret < 0 ? ret : 0;
75}
76
77int 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
96static 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
113static 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 if (dev->driver->master_set) {
120 ret = dev->driver->master_set(dev, fpriv, new_master);
121 if (unlikely(ret != 0)) {
122 drm_master_put(&dev->master);
123 }
124 }
125
126 return ret;
127}
128
129static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
130{
131 struct drm_master *old_master;
132 int ret;
133
134 lockdep_assert_held_once(&dev->master_mutex);
135
136 old_master = fpriv->master;
137 fpriv->master = drm_master_create(dev);
138 if (!fpriv->master) {
139 fpriv->master = old_master;
140 return -ENOMEM;
141 }
142
143 if (dev->driver->master_create) {
144 ret = dev->driver->master_create(dev, fpriv->master);
145 if (ret)
146 goto out_err;
147 }
148 fpriv->is_master = 1;
149 fpriv->authenticated = 1;
150
151 ret = drm_set_master(dev, fpriv, true);
152 if (ret)
153 goto out_err;
154
155 if (old_master)
156 drm_master_put(&old_master);
157
158 return 0;
159
160out_err:
161 /* drop references and restore old master on failure */
162 drm_master_put(&fpriv->master);
163 fpriv->master = old_master;
164
165 return ret;
166}
167
168int drm_setmaster_ioctl(struct drm_device *dev, void *data,
169 struct drm_file *file_priv)
170{
171 int ret = 0;
172
173 mutex_lock(&dev->master_mutex);
174 if (drm_is_current_master(file_priv))
175 goto out_unlock;
176
177 if (dev->master) {
178 ret = -EINVAL;
179 goto out_unlock;
180 }
181
182 if (!file_priv->master) {
183 ret = -EINVAL;
184 goto out_unlock;
185 }
186
187 if (!file_priv->is_master) {
188 ret = drm_new_set_master(dev, file_priv);
189 goto out_unlock;
190 }
191
192 ret = drm_set_master(dev, file_priv, false);
193out_unlock:
194 mutex_unlock(&dev->master_mutex);
195 return ret;
196}
197
198static void drm_drop_master(struct drm_device *dev,
199 struct drm_file *fpriv)
200{
201 if (dev->driver->master_drop)
202 dev->driver->master_drop(dev, fpriv);
203 drm_master_put(&dev->master);
204}
205
206int 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 (!drm_is_current_master(file_priv))
213 goto out_unlock;
214
215 if (!dev->master)
216 goto out_unlock;
217
218 ret = 0;
219 drm_drop_master(dev, file_priv);
220out_unlock:
221 mutex_unlock(&dev->master_mutex);
222 return ret;
223}
224
225int drm_master_open(struct drm_file *file_priv)
226{
227 struct drm_device *dev = file_priv->minor->dev;
228 int ret = 0;
229
230 /* if there is no current master make this fd it, but do not create
231 * any master object for render clients */
232 mutex_lock(&dev->master_mutex);
233 if (!dev->master)
234 ret = drm_new_set_master(dev, file_priv);
235 else
236 file_priv->master = drm_master_get(dev->master);
237 mutex_unlock(&dev->master_mutex);
238
239 return ret;
240}
241
242void drm_master_release(struct drm_file *file_priv)
243{
244 struct drm_device *dev = file_priv->minor->dev;
245 struct drm_master *master = file_priv->master;
246
247 mutex_lock(&dev->master_mutex);
248 if (file_priv->magic)
249 idr_remove(&file_priv->master->magic_map, file_priv->magic);
250
251 if (!drm_is_current_master(file_priv))
252 goto out;
253
254 if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
255 /*
256 * Since the master is disappearing, so is the
257 * possibility to lock.
258 */
259 mutex_lock(&dev->struct_mutex);
260 if (master->lock.hw_lock) {
261 if (dev->sigdata.lock == master->lock.hw_lock)
262 dev->sigdata.lock = NULL;
263 master->lock.hw_lock = NULL;
264 master->lock.file_priv = NULL;
265 wake_up_interruptible_all(&master->lock.lock_queue);
266 }
267 mutex_unlock(&dev->struct_mutex);
268 }
269
270 if (dev->master == file_priv->master)
271 drm_drop_master(dev, file_priv);
272out:
273 /* drop the master reference held by the file priv */
274 if (file_priv->master)
275 drm_master_put(&file_priv->master);
276 mutex_unlock(&dev->master_mutex);
277}
278
279/**
280 * drm_is_current_master - checks whether @priv is the current master
281 * @fpriv: DRM file private
282 *
283 * Checks whether @fpriv is current master on its device. This decides whether a
284 * client is allowed to run DRM_MASTER IOCTLs.
285 *
286 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
287 * - the current master is assumed to own the non-shareable display hardware.
288 */
289bool drm_is_current_master(struct drm_file *fpriv)
290{
291 return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
292}
293EXPORT_SYMBOL(drm_is_current_master);
294
295/**
296 * drm_master_get - reference a master pointer
297 * @master: struct &drm_master
298 *
299 * Increments the reference count of @master and returns a pointer to @master.
300 */
301struct drm_master *drm_master_get(struct drm_master *master)
302{
303 kref_get(&master->refcount);
304 return master;
305}
306EXPORT_SYMBOL(drm_master_get);
307
308static void drm_master_destroy(struct kref *kref)
309{
310 struct drm_master *master = container_of(kref, struct drm_master, refcount);
311 struct drm_device *dev = master->dev;
312
313 if (dev->driver->master_destroy)
314 dev->driver->master_destroy(dev, master);
315
316 drm_legacy_master_rmmaps(dev, master);
317
318 idr_destroy(&master->magic_map);
319 kfree(master->unique);
320 kfree(master);
321}
322
323/**
324 * drm_master_put - unreference and clear a master pointer
325 * @master: pointer to a pointer of struct &drm_master
326 *
327 * This decrements the &drm_master behind @master and sets it to NULL.
328 */
329void drm_master_put(struct drm_master **master)
330{
331 kref_put(&(*master)->refcount, drm_master_destroy);
332 *master = NULL;
333}
334EXPORT_SYMBOL(drm_master_put);