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_device * dev, drm_magic_t magic) 49 { 50 struct drm_file *retval = NULL; 51 struct drm_magic_entry *pt; 52 struct drm_hash_item *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, struct drm_magic_entry, 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 */ 74 static int drm_add_magic(struct drm_device * dev, struct drm_file * priv, 75 drm_magic_t magic) 76 { 77 struct drm_magic_entry *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 */ 105 static int drm_remove_magic(struct drm_device * dev, drm_magic_t magic) 106 { 107 struct drm_magic_entry *pt; 108 struct drm_hash_item *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, struct drm_magic_entry, 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 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 */ 140 int 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(dev, auth->magic)); 157 file_priv->magic = auth->magic; 158 drm_add_magic(dev, 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 */ 177 int 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(dev, auth->magic))) { 185 file->authenticated = 1; 186 drm_remove_magic(dev, auth->magic); 187 return 0; 188 } 189 return -EINVAL; 190 } 191