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 */ 48 static 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 */ 75 static 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 = kmalloc(sizeof(*entry), GFP_KERNEL); 83 if (!entry) 84 return -ENOMEM; 85 memset(entry, 0, sizeof(*entry)); 86 entry->priv = priv; 87 entry->hash_item.key = (unsigned long)magic; 88 mutex_lock(&dev->struct_mutex); 89 drm_ht_insert_item(&master->magiclist, &entry->hash_item); 90 list_add_tail(&entry->head, &master->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 */ 105 static int drm_remove_magic(struct drm_master *master, drm_magic_t magic) 106 { 107 struct drm_magic_entry *pt; 108 struct drm_hash_item *hash; 109 struct drm_device *dev = master->minor->dev; 110 111 DRM_DEBUG("%d\n", magic); 112 113 mutex_lock(&dev->struct_mutex); 114 if (drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) { 115 mutex_unlock(&dev->struct_mutex); 116 return -EINVAL; 117 } 118 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item); 119 drm_ht_remove_item(&master->magiclist, hash); 120 list_del(&pt->head); 121 mutex_unlock(&dev->struct_mutex); 122 123 kfree(pt); 124 125 return 0; 126 } 127 128 /** 129 * Get a unique magic number (ioctl). 130 * 131 * \param inode device inode. 132 * \param file_priv DRM file private. 133 * \param cmd command. 134 * \param arg pointer to a resulting drm_auth structure. 135 * \return zero on success, or a negative number on failure. 136 * 137 * If there is a magic number in drm_file::magic then use it, otherwise 138 * searches an unique non-zero magic number and add it associating it with \p 139 * file_priv. 140 */ 141 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 142 { 143 static drm_magic_t sequence = 0; 144 static DEFINE_SPINLOCK(lock); 145 struct drm_auth *auth = data; 146 147 /* Find unique magic */ 148 if (file_priv->magic) { 149 auth->magic = file_priv->magic; 150 } else { 151 do { 152 spin_lock(&lock); 153 if (!sequence) 154 ++sequence; /* reserve 0 */ 155 auth->magic = sequence++; 156 spin_unlock(&lock); 157 } while (drm_find_file(file_priv->master, auth->magic)); 158 file_priv->magic = auth->magic; 159 drm_add_magic(file_priv->master, file_priv, auth->magic); 160 } 161 162 DRM_DEBUG("%u\n", auth->magic); 163 164 return 0; 165 } 166 167 /** 168 * Authenticate with a magic. 169 * 170 * \param inode device inode. 171 * \param file_priv DRM file private. 172 * \param cmd command. 173 * \param arg pointer to a drm_auth structure. 174 * \return zero if authentication successed, or a negative number otherwise. 175 * 176 * Checks if \p file_priv is associated with the magic number passed in \arg. 177 */ 178 int drm_authmagic(struct drm_device *dev, void *data, 179 struct drm_file *file_priv) 180 { 181 struct drm_auth *auth = data; 182 struct drm_file *file; 183 184 DRM_DEBUG("%u\n", auth->magic); 185 if ((file = drm_find_file(file_priv->master, auth->magic))) { 186 file->authenticated = 1; 187 drm_remove_magic(file_priv->master, auth->magic); 188 return 0; 189 } 190 return -EINVAL; 191 } 192