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 <drm/drmP.h> 37 #include "drm_internal.h" 38 39 struct drm_magic_entry { 40 struct list_head head; 41 struct drm_hash_item hash_item; 42 struct drm_file *priv; 43 }; 44 45 /** 46 * Find the file with the given magic number. 47 * 48 * \param dev DRM device. 49 * \param magic magic number. 50 * 51 * Searches in drm_device::magiclist within all files with the same hash key 52 * the one with matching magic number, while holding the drm_device::struct_mutex 53 * lock. 54 */ 55 static struct drm_file *drm_find_file(struct drm_master *master, drm_magic_t magic) 56 { 57 struct drm_file *retval = NULL; 58 struct drm_magic_entry *pt; 59 struct drm_hash_item *hash; 60 struct drm_device *dev = master->minor->dev; 61 62 mutex_lock(&dev->struct_mutex); 63 if (!drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) { 64 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item); 65 retval = pt->priv; 66 } 67 mutex_unlock(&dev->struct_mutex); 68 return retval; 69 } 70 71 /** 72 * Adds a magic number. 73 * 74 * \param dev DRM device. 75 * \param priv file private data. 76 * \param magic magic number. 77 * 78 * Creates a drm_magic_entry structure and appends to the linked list 79 * associated the magic number hash key in drm_device::magiclist, while holding 80 * the drm_device::struct_mutex lock. 81 */ 82 static int drm_add_magic(struct drm_master *master, struct drm_file *priv, 83 drm_magic_t magic) 84 { 85 struct drm_magic_entry *entry; 86 struct drm_device *dev = master->minor->dev; 87 DRM_DEBUG("%d\n", magic); 88 89 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 90 if (!entry) 91 return -ENOMEM; 92 entry->priv = priv; 93 entry->hash_item.key = (unsigned long)magic; 94 mutex_lock(&dev->struct_mutex); 95 drm_ht_insert_item(&master->magiclist, &entry->hash_item); 96 list_add_tail(&entry->head, &master->magicfree); 97 mutex_unlock(&dev->struct_mutex); 98 99 return 0; 100 } 101 102 /** 103 * Remove a magic number. 104 * 105 * \param dev DRM device. 106 * \param magic magic number. 107 * 108 * Searches and unlinks the entry in drm_device::magiclist with the magic 109 * number hash key, while holding the drm_device::struct_mutex lock. 110 */ 111 int drm_remove_magic(struct drm_master *master, drm_magic_t magic) 112 { 113 struct drm_magic_entry *pt; 114 struct drm_hash_item *hash; 115 struct drm_device *dev = master->minor->dev; 116 117 DRM_DEBUG("%d\n", magic); 118 119 mutex_lock(&dev->struct_mutex); 120 if (drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) { 121 mutex_unlock(&dev->struct_mutex); 122 return -EINVAL; 123 } 124 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item); 125 drm_ht_remove_item(&master->magiclist, hash); 126 list_del(&pt->head); 127 mutex_unlock(&dev->struct_mutex); 128 129 kfree(pt); 130 131 return 0; 132 } 133 134 /** 135 * Get a unique magic number (ioctl). 136 * 137 * \param inode device inode. 138 * \param file_priv DRM file private. 139 * \param cmd command. 140 * \param arg pointer to a resulting drm_auth structure. 141 * \return zero on success, or a negative number on failure. 142 * 143 * If there is a magic number in drm_file::magic then use it, otherwise 144 * searches an unique non-zero magic number and add it associating it with \p 145 * file_priv. 146 * This ioctl needs protection by the drm_global_mutex, which protects 147 * struct drm_file::magic and struct drm_magic_entry::priv. 148 */ 149 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 150 { 151 static drm_magic_t sequence = 0; 152 static DEFINE_SPINLOCK(lock); 153 struct drm_auth *auth = data; 154 155 /* Find unique magic */ 156 if (file_priv->magic) { 157 auth->magic = file_priv->magic; 158 } else { 159 do { 160 spin_lock(&lock); 161 if (!sequence) 162 ++sequence; /* reserve 0 */ 163 auth->magic = sequence++; 164 spin_unlock(&lock); 165 } while (drm_find_file(file_priv->master, auth->magic)); 166 file_priv->magic = auth->magic; 167 drm_add_magic(file_priv->master, file_priv, auth->magic); 168 } 169 170 DRM_DEBUG("%u\n", auth->magic); 171 172 return 0; 173 } 174 175 /** 176 * Authenticate with a magic. 177 * 178 * \param inode device inode. 179 * \param file_priv DRM file private. 180 * \param cmd command. 181 * \param arg pointer to a drm_auth structure. 182 * \return zero if authentication successed, or a negative number otherwise. 183 * 184 * Checks if \p file_priv is associated with the magic number passed in \arg. 185 * This ioctl needs protection by the drm_global_mutex, which protects 186 * struct drm_file::magic and struct drm_magic_entry::priv. 187 */ 188 int drm_authmagic(struct drm_device *dev, void *data, 189 struct drm_file *file_priv) 190 { 191 struct drm_auth *auth = data; 192 struct drm_file *file; 193 194 DRM_DEBUG("%u\n", auth->magic); 195 if ((file = drm_find_file(file_priv->master, auth->magic))) { 196 file->authenticated = 1; 197 drm_remove_magic(file_priv->master, auth->magic); 198 return 0; 199 } 200 return -EINVAL; 201 } 202