1 /*- 2 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. 3 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice (including the next 14 * paragraph) shall be included in all copies or substantial portions of the 15 * Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 23 * OTHER DEALINGS IN THE SOFTWARE. 24 * 25 * Authors: 26 * Rickard E. (Rik) Faith <faith@valinux.com> 27 * Gareth Hughes <gareth@valinux.com> 28 * 29 * $FreeBSD: src/sys/dev/drm2/drm_auth.c,v 1.1 2012/05/22 11:07:44 kib Exp $ 30 */ 31 32 /** @file drm_auth.c 33 * Implementation of the get/authmagic ioctls implementing the authentication 34 * scheme between the master and clients. 35 */ 36 37 #include <drm/drmP.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 drm_magic_entry_t *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, drm_magic_entry_t, 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 drm_magic_entry_t *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 drm_magic_entry_t *pt; 95 struct drm_hash_item *hash; 96 97 DRM_DEBUG("%d\n", magic); 98 99 mutex_lock(&dev->struct_mutex); 100 if (drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) { 101 mutex_unlock(&dev->struct_mutex); 102 return -EINVAL; 103 } 104 pt = drm_hash_entry(hash, drm_magic_entry_t, hash_item); 105 drm_ht_remove_item(&dev->magiclist, hash); 106 list_del(&pt->head); 107 mutex_unlock(&dev->struct_mutex); 108 109 kfree(pt); 110 111 return 0; 112 } 113 114 /** 115 * Get a unique magic number (ioctl). 116 * 117 * \param inode device inode. 118 * \param file_priv DRM file private. 119 * \param cmd command. 120 * \param arg pointer to a resulting drm_auth structure. 121 * \return zero on success, or a negative number on failure. 122 * 123 * If there is a magic number in drm_file::magic then use it, otherwise 124 * searches an unique non-zero magic number and add it associating it with \p 125 * file_priv. 126 * This ioctl needs protection by the drm_global_mutex, which protects 127 * struct drm_file::magic and struct drm_magic_entry::priv. 128 */ 129 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 130 { 131 static drm_magic_t sequence = 0; 132 static struct spinlock lock = SPINLOCK_INITIALIZER(&lock, "drm_gm"); 133 struct drm_auth *auth = data; 134 135 /* Find unique magic */ 136 if (file_priv->magic) { 137 auth->magic = file_priv->magic; 138 } else { 139 do { 140 spin_lock(&lock); 141 if (!sequence) 142 ++sequence; /* reserve 0 */ 143 auth->magic = sequence++; 144 spin_unlock(&lock); 145 } while (drm_find_file(dev, auth->magic)); 146 file_priv->magic = auth->magic; 147 drm_add_magic(dev, file_priv, auth->magic); 148 } 149 150 DRM_DEBUG("%u\n", auth->magic); 151 152 return 0; 153 } 154 155 /** 156 * Authenticate with a magic. 157 * 158 * \param inode device inode. 159 * \param file_priv DRM file private. 160 * \param cmd command. 161 * \param arg pointer to a drm_auth structure. 162 * \return zero if authentication successed, or a negative number otherwise. 163 * 164 * Checks if \p file_priv is associated with the magic number passed in \arg. 165 * This ioctl needs protection by the drm_global_mutex, which protects 166 * struct drm_file::magic and struct drm_magic_entry::priv. 167 */ 168 int drm_authmagic(struct drm_device *dev, void *data, 169 struct drm_file *file_priv) 170 { 171 struct drm_auth *auth = data; 172 struct drm_file *file; 173 174 DRM_DEBUG("%u\n", auth->magic); 175 if ((file = drm_find_file(dev, auth->magic))) { 176 file->authenticated = 1; 177 drm_remove_magic(dev, auth->magic); 178 return 0; 179 } 180 return -EINVAL; 181 } 182