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 /** 40 * Find the file with the given magic number. 41 * 42 * \param dev DRM device. 43 * \param magic magic number. 44 * 45 * Searches in drm_device::magiclist within all files with the same hash key 46 * the one with matching magic number, while holding the drm_device::struct_mutex 47 * lock. 48 */ 49 static struct drm_file *drm_find_file(struct drm_device *dev, drm_magic_t magic) 50 { 51 struct drm_file *retval = NULL; 52 struct drm_magic_entry *pt; 53 struct drm_hash_item *hash; 54 55 mutex_lock(&dev->struct_mutex); 56 if (!drm_ht_find_item(&dev->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 * Inserts the given magic number into the hash table of used magic number 66 * lists. 67 */ 68 static int drm_add_magic(struct drm_device *dev, struct drm_file *priv, 69 drm_magic_t magic) 70 { 71 struct drm_magic_entry *entry; 72 73 DRM_DEBUG("%d\n", magic); 74 75 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 76 if (!entry) 77 return -ENOMEM; 78 entry->priv = priv; 79 entry->hash_item.key = (unsigned long)magic; 80 mutex_lock(&dev->struct_mutex); 81 drm_ht_insert_item(&dev->magiclist, &entry->hash_item); 82 list_add_tail(&entry->head, &dev->magicfree); 83 mutex_unlock(&dev->struct_mutex); 84 85 return 0; 86 } 87 88 /** 89 * Removes the given magic number from the hash table of used magic number 90 * lists. 91 */ 92 static int drm_remove_magic(struct drm_device *dev, drm_magic_t magic) 93 { 94 struct drm_magic_entry *pt; 95 struct drm_hash_item *hash; 96 97 DRM_DEBUG("%d\n", magic); 98 99 if (drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) { 100 return -EINVAL; 101 } 102 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item); 103 drm_ht_remove_item(&dev->magiclist, hash); 104 list_del(&pt->head); 105 106 kfree(pt); 107 108 return 0; 109 } 110 111 /** 112 * Get a unique magic number (ioctl). 113 * 114 * \param inode device inode. 115 * \param file_priv DRM file private. 116 * \param cmd command. 117 * \param arg pointer to a resulting drm_auth structure. 118 * \return zero on success, or a negative number on failure. 119 * 120 * If there is a magic number in drm_file::magic then use it, otherwise 121 * searches an unique non-zero magic number and add it associating it with \p 122 * file_priv. 123 * This ioctl needs protection by the drm_global_mutex, which protects 124 * struct drm_file::magic and struct drm_magic_entry::priv. 125 */ 126 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 127 { 128 static drm_magic_t sequence = 0; 129 static struct spinlock lock = SPINLOCK_INITIALIZER(&lock, "drm_gm"); 130 struct drm_auth *auth = data; 131 132 /* Find unique magic */ 133 if (file_priv->magic) { 134 auth->magic = file_priv->magic; 135 } else { 136 do { 137 spin_lock(&lock); 138 if (!sequence) 139 ++sequence; /* reserve 0 */ 140 auth->magic = sequence++; 141 spin_unlock(&lock); 142 } while (drm_find_file(dev, auth->magic)); 143 file_priv->magic = auth->magic; 144 drm_add_magic(dev, file_priv, auth->magic); 145 } 146 147 DRM_DEBUG("%u\n", auth->magic); 148 149 return 0; 150 } 151 152 /** 153 * drm_authmagic - Authenticate client with a magic 154 * @dev: DRM device to operate on 155 * @data: ioctl data containing the drm_auth object 156 * @file_priv: DRM file that performs the operation 157 * 158 * This looks up a DRM client by the passed magic and authenticates it. 159 * 160 * Returns: 0 on success, negative error code on failure. 161 */ 162 int drm_authmagic(struct drm_device *dev, void *data, 163 struct drm_file *file_priv) 164 { 165 struct drm_auth *auth = data; 166 struct drm_file *file; 167 168 DRM_DEBUG("%u\n", auth->magic); 169 170 mutex_lock(&dev->struct_mutex); 171 file = drm_find_file(dev, auth->magic); 172 if (file) { 173 file->authenticated = 1; 174 drm_remove_magic(dev, auth->magic); 175 } 176 mutex_unlock(&dev->struct_mutex); 177 178 return file ? 0 : -EINVAL; 179 } 180