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 drm_file_t *drm_find_file(drm_device_t * dev, drm_magic_t magic)
49{
50	drm_file_t *retval = NULL;
51	drm_magic_entry_t *pt;
52	drm_hash_item_t *hash;
53
54	mutex_lock(&dev->struct_mutex);
55	if (!drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
56		pt = drm_hash_entry(hash, drm_magic_entry_t, hash_item);
57		retval = pt->priv;
58	}
59	mutex_unlock(&dev->struct_mutex);
60	return retval;
61}
62
63/**
64 * Adds a magic number.
65 *
66 * \param dev DRM device.
67 * \param priv file private data.
68 * \param magic magic number.
69 *
70 * Creates a drm_magic_entry structure and appends to the linked list
71 * associated the magic number hash key in drm_device::magiclist, while holding
72 * the drm_device::struct_mutex lock.
73 */
74static int drm_add_magic(drm_device_t * dev, drm_file_t * priv,
75			 drm_magic_t magic)
76{
77	drm_magic_entry_t *entry;
78
79	DRM_DEBUG("%d\n", magic);
80
81	entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC);
82	if (!entry)
83		return -ENOMEM;
84	memset(entry, 0, sizeof(*entry));
85	entry->priv = priv;
86
87	entry->hash_item.key = (unsigned long)magic;
88	mutex_lock(&dev->struct_mutex);
89	drm_ht_insert_item(&dev->magiclist, &entry->hash_item);
90	list_add_tail(&entry->head, &dev->magicfree);
91	mutex_unlock(&dev->struct_mutex);
92
93	return 0;
94}
95
96/**
97 * Remove a magic number.
98 *
99 * \param dev DRM device.
100 * \param magic magic number.
101 *
102 * Searches and unlinks the entry in drm_device::magiclist with the magic
103 * number hash key, while holding the drm_device::struct_mutex lock.
104 */
105static int drm_remove_magic(drm_device_t * dev, drm_magic_t magic)
106{
107	drm_magic_entry_t *pt;
108	drm_hash_item_t *hash;
109
110	DRM_DEBUG("%d\n", magic);
111
112	mutex_lock(&dev->struct_mutex);
113	if (drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
114		mutex_unlock(&dev->struct_mutex);
115		return -EINVAL;
116	}
117	pt = drm_hash_entry(hash, drm_magic_entry_t, hash_item);
118	drm_ht_remove_item(&dev->magiclist, hash);
119	list_del(&pt->head);
120	mutex_unlock(&dev->struct_mutex);
121
122	drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
123
124	return 0;
125}
126
127/**
128 * Get a unique magic number (ioctl).
129 *
130 * \param inode device inode.
131 * \param filp file pointer.
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 * filp.
139 */
140int drm_getmagic(struct inode *inode, struct file *filp,
141		 unsigned int cmd, unsigned long arg)
142{
143	static drm_magic_t sequence = 0;
144	static DEFINE_SPINLOCK(lock);
145	drm_file_t *priv = filp->private_data;
146	drm_device_t *dev = priv->head->dev;
147	drm_auth_t auth;
148
149	/* Find unique magic */
150	if (priv->magic) {
151		auth.magic = priv->magic;
152	} else {
153		do {
154			spin_lock(&lock);
155			if (!sequence)
156				++sequence;	/* reserve 0 */
157			auth.magic = sequence++;
158			spin_unlock(&lock);
159		} while (drm_find_file(dev, auth.magic));
160		priv->magic = auth.magic;
161		drm_add_magic(dev, priv, auth.magic);
162	}
163
164	DRM_DEBUG("%u\n", auth.magic);
165	if (copy_to_user((drm_auth_t __user *) arg, &auth, sizeof(auth)))
166		return -EFAULT;
167	return 0;
168}
169
170/**
171 * Authenticate with a magic.
172 *
173 * \param inode device inode.
174 * \param filp file pointer.
175 * \param cmd command.
176 * \param arg pointer to a drm_auth structure.
177 * \return zero if authentication successed, or a negative number otherwise.
178 *
179 * Checks if \p filp is associated with the magic number passed in \arg.
180 */
181int drm_authmagic(struct inode *inode, struct file *filp,
182		  unsigned int cmd, unsigned long arg)
183{
184	drm_file_t *priv = filp->private_data;
185	drm_device_t *dev = priv->head->dev;
186	drm_auth_t auth;
187	drm_file_t *file;
188
189	if (copy_from_user(&auth, (drm_auth_t __user *) arg, sizeof(auth)))
190		return -EFAULT;
191	DRM_DEBUG("%u\n", auth.magic);
192	if ((file = drm_find_file(dev, auth.magic))) {
193		file->authenticated = 1;
194		drm_remove_magic(dev, auth.magic);
195		return 0;
196	}
197	return -EINVAL;
198}
199