/** * \file drm_auth.c * IOCTLs for authentication * * \author Rickard E. (Rik) Faith * \author Gareth Hughes */ /* * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com * * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include "drmP.h" /** * Generate a hash key from a magic. * * \param magic magic. * \return hash key. * * The key is the modulus of the hash table size, #DRM_HASH_SIZE, which must be * a power of 2. */ static int drm_hash_magic(drm_magic_t magic) { return magic & (DRM_HASH_SIZE - 1); } /** * Find the file with the given magic number. * * \param dev DRM device. * \param magic magic number. * * Searches in drm_device::magiclist within all files with the same hash key * the one with matching magic number, while holding the drm_device::struct_mutex * lock. */ static drm_file_t *drm_find_file(drm_device_t * dev, drm_magic_t magic) { drm_file_t *retval = NULL; drm_magic_entry_t *pt; int hash = drm_hash_magic(magic); mutex_lock(&dev->struct_mutex); for (pt = dev->magiclist[hash].head; pt; pt = pt->next) { if (pt->magic == magic) { retval = pt->priv; break; } } mutex_unlock(&dev->struct_mutex); return retval; } /** * Adds a magic number. * * \param dev DRM device. * \param priv file private data. * \param magic magic number. * * Creates a drm_magic_entry structure and appends to the linked list * associated the magic number hash key in drm_device::magiclist, while holding * the drm_device::struct_mutex lock. */ static int drm_add_magic(drm_device_t * dev, drm_file_t * priv, drm_magic_t magic) { int hash; drm_magic_entry_t *entry; DRM_DEBUG("%d\n", magic); hash = drm_hash_magic(magic); entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC); if (!entry) return -ENOMEM; memset(entry, 0, sizeof(*entry)); entry->magic = magic; entry->priv = priv; entry->next = NULL; mutex_lock(&dev->struct_mutex); if (dev->magiclist[hash].tail) { dev->magiclist[hash].tail->next = entry; dev->magiclist[hash].tail = entry; } else { dev->magiclist[hash].head = entry; dev->magiclist[hash].tail = entry; } mutex_unlock(&dev->struct_mutex); return 0; } /** * Remove a magic number. * * \param dev DRM device. * \param magic magic number. * * Searches and unlinks the entry in drm_device::magiclist with the magic * number hash key, while holding the drm_device::struct_mutex lock. */ static int drm_remove_magic(drm_device_t * dev, drm_magic_t magic) { drm_magic_entry_t *prev = NULL; drm_magic_entry_t *pt; int hash; DRM_DEBUG("%d\n", magic); hash = drm_hash_magic(magic); mutex_lock(&dev->struct_mutex); for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) { if (pt->magic == magic) { if (dev->magiclist[hash].head == pt) { dev->magiclist[hash].head = pt->next; } if (dev->magiclist[hash].tail == pt) { dev->magiclist[hash].tail = prev; } if (prev) { prev->next = pt->next; } mutex_unlock(&dev->struct_mutex); return 0; } } mutex_unlock(&dev->struct_mutex); drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC); return -EINVAL; } /** * Get a unique magic number (ioctl). * * \param inode device inode. * \param filp file pointer. * \param cmd command. * \param arg pointer to a resulting drm_auth structure. * \return zero on success, or a negative number on failure. * * If there is a magic number in drm_file::magic then use it, otherwise * searches an unique non-zero magic number and add it associating it with \p * filp. */ int drm_getmagic(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { static drm_magic_t sequence = 0; static DEFINE_SPINLOCK(lock); drm_file_t *priv = filp->private_data; drm_device_t *dev = priv->head->dev; drm_auth_t auth; /* Find unique magic */ if (priv->magic) { auth.magic = priv->magic; } else { do { spin_lock(&lock); if (!sequence) ++sequence; /* reserve 0 */ auth.magic = sequence++; spin_unlock(&lock); } while (drm_find_file(dev, auth.magic)); priv->magic = auth.magic; drm_add_magic(dev, priv, auth.magic); } DRM_DEBUG("%u\n", auth.magic); if (copy_to_user((drm_auth_t __user *) arg, &auth, sizeof(auth))) return -EFAULT; return 0; } /** * Authenticate with a magic. * * \param inode device inode. * \param filp file pointer. * \param cmd command. * \param arg pointer to a drm_auth structure. * \return zero if authentication successed, or a negative number otherwise. * * Checks if \p filp is associated with the magic number passed in \arg. */ int drm_authmagic(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { drm_file_t *priv = filp->private_data; drm_device_t *dev = priv->head->dev; drm_auth_t auth; drm_file_t *file; if (copy_from_user(&auth, (drm_auth_t __user *) arg, sizeof(auth))) return -EFAULT; DRM_DEBUG("%u\n", auth.magic); if ((file = drm_find_file(dev, auth.magic))) { file->authenticated = 1; drm_remove_magic(dev, auth.magic); return 0; } return -EINVAL; }