1217 lines
31 KiB
C
1217 lines
31 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Basic authentication token and access key management
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*
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* Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/export.h>
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#include <linux/init.h>
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#include <linux/poison.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/workqueue.h>
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#include <linux/random.h>
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#include <linux/ima.h>
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#include <linux/err.h>
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#include "internal.h"
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struct kmem_cache *key_jar;
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struct rb_root key_serial_tree; /* tree of keys indexed by serial */
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DEFINE_SPINLOCK(key_serial_lock);
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struct rb_root key_user_tree; /* tree of quota records indexed by UID */
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DEFINE_SPINLOCK(key_user_lock);
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unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */
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unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */
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unsigned int key_quota_maxkeys = 200; /* general key count quota */
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unsigned int key_quota_maxbytes = 20000; /* general key space quota */
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static LIST_HEAD(key_types_list);
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static DECLARE_RWSEM(key_types_sem);
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/* We serialise key instantiation and link */
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DEFINE_MUTEX(key_construction_mutex);
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#ifdef KEY_DEBUGGING
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void __key_check(const struct key *key)
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{
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printk("__key_check: key %p {%08x} should be {%08x}\n",
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key, key->magic, KEY_DEBUG_MAGIC);
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BUG();
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}
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#endif
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/*
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* Get the key quota record for a user, allocating a new record if one doesn't
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* already exist.
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*/
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struct key_user *key_user_lookup(kuid_t uid)
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{
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struct key_user *candidate = NULL, *user;
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struct rb_node *parent, **p;
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try_again:
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parent = NULL;
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p = &key_user_tree.rb_node;
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spin_lock(&key_user_lock);
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/* search the tree for a user record with a matching UID */
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while (*p) {
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parent = *p;
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user = rb_entry(parent, struct key_user, node);
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if (uid_lt(uid, user->uid))
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p = &(*p)->rb_left;
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else if (uid_gt(uid, user->uid))
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p = &(*p)->rb_right;
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else
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goto found;
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}
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/* if we get here, we failed to find a match in the tree */
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if (!candidate) {
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/* allocate a candidate user record if we don't already have
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* one */
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spin_unlock(&key_user_lock);
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user = NULL;
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candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
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if (unlikely(!candidate))
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goto out;
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/* the allocation may have scheduled, so we need to repeat the
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* search lest someone else added the record whilst we were
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* asleep */
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goto try_again;
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}
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/* if we get here, then the user record still hadn't appeared on the
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* second pass - so we use the candidate record */
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refcount_set(&candidate->usage, 1);
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atomic_set(&candidate->nkeys, 0);
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atomic_set(&candidate->nikeys, 0);
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candidate->uid = uid;
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candidate->qnkeys = 0;
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candidate->qnbytes = 0;
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spin_lock_init(&candidate->lock);
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mutex_init(&candidate->cons_lock);
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rb_link_node(&candidate->node, parent, p);
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rb_insert_color(&candidate->node, &key_user_tree);
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spin_unlock(&key_user_lock);
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user = candidate;
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goto out;
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/* okay - we found a user record for this UID */
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found:
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refcount_inc(&user->usage);
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spin_unlock(&key_user_lock);
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kfree(candidate);
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out:
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return user;
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}
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/*
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* Dispose of a user structure
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*/
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void key_user_put(struct key_user *user)
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{
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if (refcount_dec_and_lock(&user->usage, &key_user_lock)) {
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rb_erase(&user->node, &key_user_tree);
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spin_unlock(&key_user_lock);
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kfree(user);
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}
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}
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/*
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* Allocate a serial number for a key. These are assigned randomly to avoid
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* security issues through covert channel problems.
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*/
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static inline void key_alloc_serial(struct key *key)
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{
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struct rb_node *parent, **p;
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struct key *xkey;
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/* propose a random serial number and look for a hole for it in the
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* serial number tree */
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do {
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get_random_bytes(&key->serial, sizeof(key->serial));
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key->serial >>= 1; /* negative numbers are not permitted */
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} while (key->serial < 3);
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spin_lock(&key_serial_lock);
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attempt_insertion:
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parent = NULL;
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p = &key_serial_tree.rb_node;
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while (*p) {
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parent = *p;
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xkey = rb_entry(parent, struct key, serial_node);
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if (key->serial < xkey->serial)
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p = &(*p)->rb_left;
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else if (key->serial > xkey->serial)
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p = &(*p)->rb_right;
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else
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goto serial_exists;
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}
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/* we've found a suitable hole - arrange for this key to occupy it */
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rb_link_node(&key->serial_node, parent, p);
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rb_insert_color(&key->serial_node, &key_serial_tree);
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spin_unlock(&key_serial_lock);
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return;
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/* we found a key with the proposed serial number - walk the tree from
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* that point looking for the next unused serial number */
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serial_exists:
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for (;;) {
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key->serial++;
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if (key->serial < 3) {
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key->serial = 3;
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goto attempt_insertion;
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}
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parent = rb_next(parent);
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if (!parent)
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goto attempt_insertion;
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xkey = rb_entry(parent, struct key, serial_node);
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if (key->serial < xkey->serial)
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goto attempt_insertion;
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}
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}
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/**
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* key_alloc - Allocate a key of the specified type.
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* @type: The type of key to allocate.
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* @desc: The key description to allow the key to be searched out.
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* @uid: The owner of the new key.
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* @gid: The group ID for the new key's group permissions.
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* @cred: The credentials specifying UID namespace.
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* @perm: The permissions mask of the new key.
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* @flags: Flags specifying quota properties.
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* @restrict_link: Optional link restriction for new keyrings.
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*
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* Allocate a key of the specified type with the attributes given. The key is
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* returned in an uninstantiated state and the caller needs to instantiate the
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* key before returning.
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*
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* The restrict_link structure (if not NULL) will be freed when the
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* keyring is destroyed, so it must be dynamically allocated.
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*
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* The user's key count quota is updated to reflect the creation of the key and
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* the user's key data quota has the default for the key type reserved. The
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* instantiation function should amend this as necessary. If insufficient
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* quota is available, -EDQUOT will be returned.
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*
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* The LSM security modules can prevent a key being created, in which case
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* -EACCES will be returned.
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*
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* Returns a pointer to the new key if successful and an error code otherwise.
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*
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* Note that the caller needs to ensure the key type isn't uninstantiated.
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* Internally this can be done by locking key_types_sem. Externally, this can
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* be done by either never unregistering the key type, or making sure
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* key_alloc() calls don't race with module unloading.
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*/
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struct key *key_alloc(struct key_type *type, const char *desc,
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kuid_t uid, kgid_t gid, const struct cred *cred,
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key_perm_t perm, unsigned long flags,
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struct key_restriction *restrict_link)
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{
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struct key_user *user = NULL;
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struct key *key;
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size_t desclen, quotalen;
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int ret;
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key = ERR_PTR(-EINVAL);
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if (!desc || !*desc)
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goto error;
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if (type->vet_description) {
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ret = type->vet_description(desc);
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if (ret < 0) {
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key = ERR_PTR(ret);
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goto error;
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}
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}
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desclen = strlen(desc);
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quotalen = desclen + 1 + type->def_datalen;
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/* get hold of the key tracking for this user */
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user = key_user_lookup(uid);
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if (!user)
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goto no_memory_1;
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/* check that the user's quota permits allocation of another key and
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* its description */
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
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unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
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key_quota_root_maxkeys : key_quota_maxkeys;
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unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
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key_quota_root_maxbytes : key_quota_maxbytes;
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spin_lock(&user->lock);
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if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
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if (user->qnkeys + 1 > maxkeys ||
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user->qnbytes + quotalen > maxbytes ||
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user->qnbytes + quotalen < user->qnbytes)
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goto no_quota;
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}
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user->qnkeys++;
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user->qnbytes += quotalen;
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spin_unlock(&user->lock);
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}
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/* allocate and initialise the key and its description */
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key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
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if (!key)
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goto no_memory_2;
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key->index_key.desc_len = desclen;
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key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
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if (!key->index_key.description)
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goto no_memory_3;
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key->index_key.type = type;
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key_set_index_key(&key->index_key);
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refcount_set(&key->usage, 1);
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init_rwsem(&key->sem);
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lockdep_set_class(&key->sem, &type->lock_class);
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key->user = user;
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key->quotalen = quotalen;
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key->datalen = type->def_datalen;
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key->uid = uid;
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key->gid = gid;
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key->perm = perm;
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key->restrict_link = restrict_link;
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key->last_used_at = ktime_get_real_seconds();
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
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key->flags |= 1 << KEY_FLAG_IN_QUOTA;
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if (flags & KEY_ALLOC_BUILT_IN)
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key->flags |= 1 << KEY_FLAG_BUILTIN;
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if (flags & KEY_ALLOC_UID_KEYRING)
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key->flags |= 1 << KEY_FLAG_UID_KEYRING;
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#ifdef KEY_DEBUGGING
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key->magic = KEY_DEBUG_MAGIC;
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#endif
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/* let the security module know about the key */
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ret = security_key_alloc(key, cred, flags);
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if (ret < 0)
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goto security_error;
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/* publish the key by giving it a serial number */
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refcount_inc(&key->domain_tag->usage);
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atomic_inc(&user->nkeys);
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key_alloc_serial(key);
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error:
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return key;
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security_error:
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kfree(key->description);
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kmem_cache_free(key_jar, key);
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
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spin_lock(&user->lock);
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user->qnkeys--;
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user->qnbytes -= quotalen;
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spin_unlock(&user->lock);
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}
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key_user_put(user);
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key = ERR_PTR(ret);
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goto error;
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no_memory_3:
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kmem_cache_free(key_jar, key);
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no_memory_2:
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
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spin_lock(&user->lock);
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user->qnkeys--;
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user->qnbytes -= quotalen;
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spin_unlock(&user->lock);
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}
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key_user_put(user);
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no_memory_1:
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key = ERR_PTR(-ENOMEM);
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goto error;
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no_quota:
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spin_unlock(&user->lock);
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key_user_put(user);
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key = ERR_PTR(-EDQUOT);
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goto error;
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}
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EXPORT_SYMBOL(key_alloc);
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/**
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* key_payload_reserve - Adjust data quota reservation for the key's payload
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* @key: The key to make the reservation for.
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* @datalen: The amount of data payload the caller now wants.
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*
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* Adjust the amount of the owning user's key data quota that a key reserves.
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* If the amount is increased, then -EDQUOT may be returned if there isn't
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* enough free quota available.
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*
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* If successful, 0 is returned.
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*/
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int key_payload_reserve(struct key *key, size_t datalen)
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{
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int delta = (int)datalen - key->datalen;
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int ret = 0;
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key_check(key);
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/* contemplate the quota adjustment */
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if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
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unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
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key_quota_root_maxbytes : key_quota_maxbytes;
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spin_lock(&key->user->lock);
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if (delta > 0 &&
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(key->user->qnbytes + delta > maxbytes ||
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key->user->qnbytes + delta < key->user->qnbytes)) {
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ret = -EDQUOT;
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}
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else {
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key->user->qnbytes += delta;
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key->quotalen += delta;
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}
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spin_unlock(&key->user->lock);
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}
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/* change the recorded data length if that didn't generate an error */
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if (ret == 0)
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key->datalen = datalen;
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return ret;
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}
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EXPORT_SYMBOL(key_payload_reserve);
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/*
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* Change the key state to being instantiated.
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*/
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static void mark_key_instantiated(struct key *key, int reject_error)
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{
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/* Commit the payload before setting the state; barrier versus
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* key_read_state().
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*/
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smp_store_release(&key->state,
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(reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
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}
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|
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/*
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* Instantiate a key and link it into the target keyring atomically. Must be
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* called with the target keyring's semaphore writelocked. The target key's
|
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* semaphore need not be locked as instantiation is serialised by
|
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* key_construction_mutex.
|
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*/
|
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static int __key_instantiate_and_link(struct key *key,
|
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struct key_preparsed_payload *prep,
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struct key *keyring,
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struct key *authkey,
|
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struct assoc_array_edit **_edit)
|
|
{
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int ret, awaken;
|
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|
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key_check(key);
|
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key_check(keyring);
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|
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awaken = 0;
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ret = -EBUSY;
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|
|
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mutex_lock(&key_construction_mutex);
|
|
|
|
/* can't instantiate twice */
|
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if (key->state == KEY_IS_UNINSTANTIATED) {
|
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/* instantiate the key */
|
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ret = key->type->instantiate(key, prep);
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|
|
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if (ret == 0) {
|
|
/* mark the key as being instantiated */
|
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atomic_inc(&key->user->nikeys);
|
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mark_key_instantiated(key, 0);
|
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notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);
|
|
|
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if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
|
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awaken = 1;
|
|
|
|
/* and link it into the destination keyring */
|
|
if (keyring) {
|
|
if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
|
|
set_bit(KEY_FLAG_KEEP, &key->flags);
|
|
|
|
__key_link(keyring, key, _edit);
|
|
}
|
|
|
|
/* disable the authorisation key */
|
|
if (authkey)
|
|
key_invalidate(authkey);
|
|
|
|
if (prep->expiry != TIME64_MAX) {
|
|
key->expiry = prep->expiry;
|
|
key_schedule_gc(prep->expiry + key_gc_delay);
|
|
}
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&key_construction_mutex);
|
|
|
|
/* wake up anyone waiting for a key to be constructed */
|
|
if (awaken)
|
|
wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* key_instantiate_and_link - Instantiate a key and link it into the keyring.
|
|
* @key: The key to instantiate.
|
|
* @data: The data to use to instantiate the keyring.
|
|
* @datalen: The length of @data.
|
|
* @keyring: Keyring to create a link in on success (or NULL).
|
|
* @authkey: The authorisation token permitting instantiation.
|
|
*
|
|
* Instantiate a key that's in the uninstantiated state using the provided data
|
|
* and, if successful, link it in to the destination keyring if one is
|
|
* supplied.
|
|
*
|
|
* If successful, 0 is returned, the authorisation token is revoked and anyone
|
|
* waiting for the key is woken up. If the key was already instantiated,
|
|
* -EBUSY will be returned.
|
|
*/
|
|
int key_instantiate_and_link(struct key *key,
|
|
const void *data,
|
|
size_t datalen,
|
|
struct key *keyring,
|
|
struct key *authkey)
|
|
{
|
|
struct key_preparsed_payload prep;
|
|
struct assoc_array_edit *edit = NULL;
|
|
int ret;
|
|
|
|
memset(&prep, 0, sizeof(prep));
|
|
prep.data = data;
|
|
prep.datalen = datalen;
|
|
prep.quotalen = key->type->def_datalen;
|
|
prep.expiry = TIME64_MAX;
|
|
if (key->type->preparse) {
|
|
ret = key->type->preparse(&prep);
|
|
if (ret < 0)
|
|
goto error;
|
|
}
|
|
|
|
if (keyring) {
|
|
ret = __key_link_lock(keyring, &key->index_key);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
ret = __key_link_begin(keyring, &key->index_key, &edit);
|
|
if (ret < 0)
|
|
goto error_link_end;
|
|
|
|
if (keyring->restrict_link && keyring->restrict_link->check) {
|
|
struct key_restriction *keyres = keyring->restrict_link;
|
|
|
|
ret = keyres->check(keyring, key->type, &prep.payload,
|
|
keyres->key);
|
|
if (ret < 0)
|
|
goto error_link_end;
|
|
}
|
|
}
|
|
|
|
ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
|
|
|
|
error_link_end:
|
|
if (keyring)
|
|
__key_link_end(keyring, &key->index_key, edit);
|
|
|
|
error:
|
|
if (key->type->preparse)
|
|
key->type->free_preparse(&prep);
|
|
return ret;
|
|
}
|
|
|
|
EXPORT_SYMBOL(key_instantiate_and_link);
|
|
|
|
/**
|
|
* key_reject_and_link - Negatively instantiate a key and link it into the keyring.
|
|
* @key: The key to instantiate.
|
|
* @timeout: The timeout on the negative key.
|
|
* @error: The error to return when the key is hit.
|
|
* @keyring: Keyring to create a link in on success (or NULL).
|
|
* @authkey: The authorisation token permitting instantiation.
|
|
*
|
|
* Negatively instantiate a key that's in the uninstantiated state and, if
|
|
* successful, set its timeout and stored error and link it in to the
|
|
* destination keyring if one is supplied. The key and any links to the key
|
|
* will be automatically garbage collected after the timeout expires.
|
|
*
|
|
* Negative keys are used to rate limit repeated request_key() calls by causing
|
|
* them to return the stored error code (typically ENOKEY) until the negative
|
|
* key expires.
|
|
*
|
|
* If successful, 0 is returned, the authorisation token is revoked and anyone
|
|
* waiting for the key is woken up. If the key was already instantiated,
|
|
* -EBUSY will be returned.
|
|
*/
|
|
int key_reject_and_link(struct key *key,
|
|
unsigned timeout,
|
|
unsigned error,
|
|
struct key *keyring,
|
|
struct key *authkey)
|
|
{
|
|
struct assoc_array_edit *edit = NULL;
|
|
int ret, awaken, link_ret = 0;
|
|
|
|
key_check(key);
|
|
key_check(keyring);
|
|
|
|
awaken = 0;
|
|
ret = -EBUSY;
|
|
|
|
if (keyring) {
|
|
if (keyring->restrict_link)
|
|
return -EPERM;
|
|
|
|
link_ret = __key_link_lock(keyring, &key->index_key);
|
|
if (link_ret == 0) {
|
|
link_ret = __key_link_begin(keyring, &key->index_key, &edit);
|
|
if (link_ret < 0)
|
|
__key_link_end(keyring, &key->index_key, edit);
|
|
}
|
|
}
|
|
|
|
mutex_lock(&key_construction_mutex);
|
|
|
|
/* can't instantiate twice */
|
|
if (key->state == KEY_IS_UNINSTANTIATED) {
|
|
/* mark the key as being negatively instantiated */
|
|
atomic_inc(&key->user->nikeys);
|
|
mark_key_instantiated(key, -error);
|
|
notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
|
|
key->expiry = ktime_get_real_seconds() + timeout;
|
|
key_schedule_gc(key->expiry + key_gc_delay);
|
|
|
|
if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
|
|
awaken = 1;
|
|
|
|
ret = 0;
|
|
|
|
/* and link it into the destination keyring */
|
|
if (keyring && link_ret == 0)
|
|
__key_link(keyring, key, &edit);
|
|
|
|
/* disable the authorisation key */
|
|
if (authkey)
|
|
key_invalidate(authkey);
|
|
}
|
|
|
|
mutex_unlock(&key_construction_mutex);
|
|
|
|
if (keyring && link_ret == 0)
|
|
__key_link_end(keyring, &key->index_key, edit);
|
|
|
|
/* wake up anyone waiting for a key to be constructed */
|
|
if (awaken)
|
|
wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
|
|
|
|
return ret == 0 ? link_ret : ret;
|
|
}
|
|
EXPORT_SYMBOL(key_reject_and_link);
|
|
|
|
/**
|
|
* key_put - Discard a reference to a key.
|
|
* @key: The key to discard a reference from.
|
|
*
|
|
* Discard a reference to a key, and when all the references are gone, we
|
|
* schedule the cleanup task to come and pull it out of the tree in process
|
|
* context at some later time.
|
|
*/
|
|
void key_put(struct key *key)
|
|
{
|
|
if (key) {
|
|
key_check(key);
|
|
|
|
if (refcount_dec_and_test(&key->usage))
|
|
schedule_work(&key_gc_work);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(key_put);
|
|
|
|
/*
|
|
* Find a key by its serial number.
|
|
*/
|
|
struct key *key_lookup(key_serial_t id)
|
|
{
|
|
struct rb_node *n;
|
|
struct key *key;
|
|
|
|
spin_lock(&key_serial_lock);
|
|
|
|
/* search the tree for the specified key */
|
|
n = key_serial_tree.rb_node;
|
|
while (n) {
|
|
key = rb_entry(n, struct key, serial_node);
|
|
|
|
if (id < key->serial)
|
|
n = n->rb_left;
|
|
else if (id > key->serial)
|
|
n = n->rb_right;
|
|
else
|
|
goto found;
|
|
}
|
|
|
|
not_found:
|
|
key = ERR_PTR(-ENOKEY);
|
|
goto error;
|
|
|
|
found:
|
|
/* A key is allowed to be looked up only if someone still owns a
|
|
* reference to it - otherwise it's awaiting the gc.
|
|
*/
|
|
if (!refcount_inc_not_zero(&key->usage))
|
|
goto not_found;
|
|
|
|
error:
|
|
spin_unlock(&key_serial_lock);
|
|
return key;
|
|
}
|
|
|
|
/*
|
|
* Find and lock the specified key type against removal.
|
|
*
|
|
* We return with the sem read-locked if successful. If the type wasn't
|
|
* available -ENOKEY is returned instead.
|
|
*/
|
|
struct key_type *key_type_lookup(const char *type)
|
|
{
|
|
struct key_type *ktype;
|
|
|
|
down_read(&key_types_sem);
|
|
|
|
/* look up the key type to see if it's one of the registered kernel
|
|
* types */
|
|
list_for_each_entry(ktype, &key_types_list, link) {
|
|
if (strcmp(ktype->name, type) == 0)
|
|
goto found_kernel_type;
|
|
}
|
|
|
|
up_read(&key_types_sem);
|
|
ktype = ERR_PTR(-ENOKEY);
|
|
|
|
found_kernel_type:
|
|
return ktype;
|
|
}
|
|
|
|
void key_set_timeout(struct key *key, unsigned timeout)
|
|
{
|
|
time64_t expiry = 0;
|
|
|
|
/* make the changes with the locks held to prevent races */
|
|
down_write(&key->sem);
|
|
|
|
if (timeout > 0)
|
|
expiry = ktime_get_real_seconds() + timeout;
|
|
|
|
key->expiry = expiry;
|
|
key_schedule_gc(key->expiry + key_gc_delay);
|
|
|
|
up_write(&key->sem);
|
|
}
|
|
EXPORT_SYMBOL_GPL(key_set_timeout);
|
|
|
|
/*
|
|
* Unlock a key type locked by key_type_lookup().
|
|
*/
|
|
void key_type_put(struct key_type *ktype)
|
|
{
|
|
up_read(&key_types_sem);
|
|
}
|
|
|
|
/*
|
|
* Attempt to update an existing key.
|
|
*
|
|
* The key is given to us with an incremented refcount that we need to discard
|
|
* if we get an error.
|
|
*/
|
|
static inline key_ref_t __key_update(key_ref_t key_ref,
|
|
struct key_preparsed_payload *prep)
|
|
{
|
|
struct key *key = key_ref_to_ptr(key_ref);
|
|
int ret;
|
|
|
|
/* need write permission on the key to update it */
|
|
ret = key_permission(key_ref, KEY_NEED_WRITE);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
ret = -EEXIST;
|
|
if (!key->type->update)
|
|
goto error;
|
|
|
|
down_write(&key->sem);
|
|
|
|
ret = key->type->update(key, prep);
|
|
if (ret == 0) {
|
|
/* Updating a negative key positively instantiates it */
|
|
mark_key_instantiated(key, 0);
|
|
notify_key(key, NOTIFY_KEY_UPDATED, 0);
|
|
}
|
|
|
|
up_write(&key->sem);
|
|
|
|
if (ret < 0)
|
|
goto error;
|
|
out:
|
|
return key_ref;
|
|
|
|
error:
|
|
key_put(key);
|
|
key_ref = ERR_PTR(ret);
|
|
goto out;
|
|
}
|
|
|
|
/**
|
|
* key_create_or_update - Update or create and instantiate a key.
|
|
* @keyring_ref: A pointer to the destination keyring with possession flag.
|
|
* @type: The type of key.
|
|
* @description: The searchable description for the key.
|
|
* @payload: The data to use to instantiate or update the key.
|
|
* @plen: The length of @payload.
|
|
* @perm: The permissions mask for a new key.
|
|
* @flags: The quota flags for a new key.
|
|
*
|
|
* Search the destination keyring for a key of the same description and if one
|
|
* is found, update it, otherwise create and instantiate a new one and create a
|
|
* link to it from that keyring.
|
|
*
|
|
* If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
|
|
* concocted.
|
|
*
|
|
* Returns a pointer to the new key if successful, -ENODEV if the key type
|
|
* wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
|
|
* caller isn't permitted to modify the keyring or the LSM did not permit
|
|
* creation of the key.
|
|
*
|
|
* On success, the possession flag from the keyring ref will be tacked on to
|
|
* the key ref before it is returned.
|
|
*/
|
|
key_ref_t key_create_or_update(key_ref_t keyring_ref,
|
|
const char *type,
|
|
const char *description,
|
|
const void *payload,
|
|
size_t plen,
|
|
key_perm_t perm,
|
|
unsigned long flags)
|
|
{
|
|
struct keyring_index_key index_key = {
|
|
.description = description,
|
|
};
|
|
struct key_preparsed_payload prep;
|
|
struct assoc_array_edit *edit = NULL;
|
|
const struct cred *cred = current_cred();
|
|
struct key *keyring, *key = NULL;
|
|
key_ref_t key_ref;
|
|
int ret;
|
|
struct key_restriction *restrict_link = NULL;
|
|
|
|
/* look up the key type to see if it's one of the registered kernel
|
|
* types */
|
|
index_key.type = key_type_lookup(type);
|
|
if (IS_ERR(index_key.type)) {
|
|
key_ref = ERR_PTR(-ENODEV);
|
|
goto error;
|
|
}
|
|
|
|
key_ref = ERR_PTR(-EINVAL);
|
|
if (!index_key.type->instantiate ||
|
|
(!index_key.description && !index_key.type->preparse))
|
|
goto error_put_type;
|
|
|
|
keyring = key_ref_to_ptr(keyring_ref);
|
|
|
|
key_check(keyring);
|
|
|
|
if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
|
|
restrict_link = keyring->restrict_link;
|
|
|
|
key_ref = ERR_PTR(-ENOTDIR);
|
|
if (keyring->type != &key_type_keyring)
|
|
goto error_put_type;
|
|
|
|
memset(&prep, 0, sizeof(prep));
|
|
prep.data = payload;
|
|
prep.datalen = plen;
|
|
prep.quotalen = index_key.type->def_datalen;
|
|
prep.expiry = TIME64_MAX;
|
|
if (index_key.type->preparse) {
|
|
ret = index_key.type->preparse(&prep);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_free_prep;
|
|
}
|
|
if (!index_key.description)
|
|
index_key.description = prep.description;
|
|
key_ref = ERR_PTR(-EINVAL);
|
|
if (!index_key.description)
|
|
goto error_free_prep;
|
|
}
|
|
index_key.desc_len = strlen(index_key.description);
|
|
key_set_index_key(&index_key);
|
|
|
|
ret = __key_link_lock(keyring, &index_key);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_free_prep;
|
|
}
|
|
|
|
ret = __key_link_begin(keyring, &index_key, &edit);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_link_end;
|
|
}
|
|
|
|
if (restrict_link && restrict_link->check) {
|
|
ret = restrict_link->check(keyring, index_key.type,
|
|
&prep.payload, restrict_link->key);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_link_end;
|
|
}
|
|
}
|
|
|
|
/* if we're going to allocate a new key, we're going to have
|
|
* to modify the keyring */
|
|
ret = key_permission(keyring_ref, KEY_NEED_WRITE);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_link_end;
|
|
}
|
|
|
|
/* if it's possible to update this type of key, search for an existing
|
|
* key of the same type and description in the destination keyring and
|
|
* update that instead if possible
|
|
*/
|
|
if (index_key.type->update) {
|
|
key_ref = find_key_to_update(keyring_ref, &index_key);
|
|
if (key_ref)
|
|
goto found_matching_key;
|
|
}
|
|
|
|
/* if the client doesn't provide, decide on the permissions we want */
|
|
if (perm == KEY_PERM_UNDEF) {
|
|
perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
|
|
perm |= KEY_USR_VIEW;
|
|
|
|
if (index_key.type->read)
|
|
perm |= KEY_POS_READ;
|
|
|
|
if (index_key.type == &key_type_keyring ||
|
|
index_key.type->update)
|
|
perm |= KEY_POS_WRITE;
|
|
}
|
|
|
|
/* allocate a new key */
|
|
key = key_alloc(index_key.type, index_key.description,
|
|
cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
|
|
if (IS_ERR(key)) {
|
|
key_ref = ERR_CAST(key);
|
|
goto error_link_end;
|
|
}
|
|
|
|
/* instantiate it and link it into the target keyring */
|
|
ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
|
|
if (ret < 0) {
|
|
key_put(key);
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_link_end;
|
|
}
|
|
|
|
ima_post_key_create_or_update(keyring, key, payload, plen,
|
|
flags, true);
|
|
|
|
key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
|
|
|
|
error_link_end:
|
|
__key_link_end(keyring, &index_key, edit);
|
|
error_free_prep:
|
|
if (index_key.type->preparse)
|
|
index_key.type->free_preparse(&prep);
|
|
error_put_type:
|
|
key_type_put(index_key.type);
|
|
error:
|
|
return key_ref;
|
|
|
|
found_matching_key:
|
|
/* we found a matching key, so we're going to try to update it
|
|
* - we can drop the locks first as we have the key pinned
|
|
*/
|
|
__key_link_end(keyring, &index_key, edit);
|
|
|
|
key = key_ref_to_ptr(key_ref);
|
|
if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
|
|
ret = wait_for_key_construction(key, true);
|
|
if (ret < 0) {
|
|
key_ref_put(key_ref);
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_free_prep;
|
|
}
|
|
}
|
|
|
|
key_ref = __key_update(key_ref, &prep);
|
|
|
|
if (!IS_ERR(key_ref))
|
|
ima_post_key_create_or_update(keyring, key,
|
|
payload, plen,
|
|
flags, false);
|
|
|
|
goto error_free_prep;
|
|
}
|
|
EXPORT_SYMBOL(key_create_or_update);
|
|
|
|
/**
|
|
* key_update - Update a key's contents.
|
|
* @key_ref: The pointer (plus possession flag) to the key.
|
|
* @payload: The data to be used to update the key.
|
|
* @plen: The length of @payload.
|
|
*
|
|
* Attempt to update the contents of a key with the given payload data. The
|
|
* caller must be granted Write permission on the key. Negative keys can be
|
|
* instantiated by this method.
|
|
*
|
|
* Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
|
|
* type does not support updating. The key type may return other errors.
|
|
*/
|
|
int key_update(key_ref_t key_ref, const void *payload, size_t plen)
|
|
{
|
|
struct key_preparsed_payload prep;
|
|
struct key *key = key_ref_to_ptr(key_ref);
|
|
int ret;
|
|
|
|
key_check(key);
|
|
|
|
/* the key must be writable */
|
|
ret = key_permission(key_ref, KEY_NEED_WRITE);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* attempt to update it if supported */
|
|
if (!key->type->update)
|
|
return -EOPNOTSUPP;
|
|
|
|
memset(&prep, 0, sizeof(prep));
|
|
prep.data = payload;
|
|
prep.datalen = plen;
|
|
prep.quotalen = key->type->def_datalen;
|
|
prep.expiry = TIME64_MAX;
|
|
if (key->type->preparse) {
|
|
ret = key->type->preparse(&prep);
|
|
if (ret < 0)
|
|
goto error;
|
|
}
|
|
|
|
down_write(&key->sem);
|
|
|
|
ret = key->type->update(key, &prep);
|
|
if (ret == 0) {
|
|
/* Updating a negative key positively instantiates it */
|
|
mark_key_instantiated(key, 0);
|
|
notify_key(key, NOTIFY_KEY_UPDATED, 0);
|
|
}
|
|
|
|
up_write(&key->sem);
|
|
|
|
error:
|
|
if (key->type->preparse)
|
|
key->type->free_preparse(&prep);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(key_update);
|
|
|
|
/**
|
|
* key_revoke - Revoke a key.
|
|
* @key: The key to be revoked.
|
|
*
|
|
* Mark a key as being revoked and ask the type to free up its resources. The
|
|
* revocation timeout is set and the key and all its links will be
|
|
* automatically garbage collected after key_gc_delay amount of time if they
|
|
* are not manually dealt with first.
|
|
*/
|
|
void key_revoke(struct key *key)
|
|
{
|
|
time64_t time;
|
|
|
|
key_check(key);
|
|
|
|
/* make sure no one's trying to change or use the key when we mark it
|
|
* - we tell lockdep that we might nest because we might be revoking an
|
|
* authorisation key whilst holding the sem on a key we've just
|
|
* instantiated
|
|
*/
|
|
down_write_nested(&key->sem, 1);
|
|
if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
|
|
notify_key(key, NOTIFY_KEY_REVOKED, 0);
|
|
if (key->type->revoke)
|
|
key->type->revoke(key);
|
|
|
|
/* set the death time to no more than the expiry time */
|
|
time = ktime_get_real_seconds();
|
|
if (key->revoked_at == 0 || key->revoked_at > time) {
|
|
key->revoked_at = time;
|
|
key_schedule_gc(key->revoked_at + key_gc_delay);
|
|
}
|
|
}
|
|
|
|
up_write(&key->sem);
|
|
}
|
|
EXPORT_SYMBOL(key_revoke);
|
|
|
|
/**
|
|
* key_invalidate - Invalidate a key.
|
|
* @key: The key to be invalidated.
|
|
*
|
|
* Mark a key as being invalidated and have it cleaned up immediately. The key
|
|
* is ignored by all searches and other operations from this point.
|
|
*/
|
|
void key_invalidate(struct key *key)
|
|
{
|
|
kenter("%d", key_serial(key));
|
|
|
|
key_check(key);
|
|
|
|
if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
|
|
down_write_nested(&key->sem, 1);
|
|
if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
|
|
notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
|
|
key_schedule_gc_links();
|
|
}
|
|
up_write(&key->sem);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(key_invalidate);
|
|
|
|
/**
|
|
* generic_key_instantiate - Simple instantiation of a key from preparsed data
|
|
* @key: The key to be instantiated
|
|
* @prep: The preparsed data to load.
|
|
*
|
|
* Instantiate a key from preparsed data. We assume we can just copy the data
|
|
* in directly and clear the old pointers.
|
|
*
|
|
* This can be pointed to directly by the key type instantiate op pointer.
|
|
*/
|
|
int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
|
|
{
|
|
int ret;
|
|
|
|
pr_devel("==>%s()\n", __func__);
|
|
|
|
ret = key_payload_reserve(key, prep->quotalen);
|
|
if (ret == 0) {
|
|
rcu_assign_keypointer(key, prep->payload.data[0]);
|
|
key->payload.data[1] = prep->payload.data[1];
|
|
key->payload.data[2] = prep->payload.data[2];
|
|
key->payload.data[3] = prep->payload.data[3];
|
|
prep->payload.data[0] = NULL;
|
|
prep->payload.data[1] = NULL;
|
|
prep->payload.data[2] = NULL;
|
|
prep->payload.data[3] = NULL;
|
|
}
|
|
pr_devel("<==%s() = %d\n", __func__, ret);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(generic_key_instantiate);
|
|
|
|
/**
|
|
* register_key_type - Register a type of key.
|
|
* @ktype: The new key type.
|
|
*
|
|
* Register a new key type.
|
|
*
|
|
* Returns 0 on success or -EEXIST if a type of this name already exists.
|
|
*/
|
|
int register_key_type(struct key_type *ktype)
|
|
{
|
|
struct key_type *p;
|
|
int ret;
|
|
|
|
memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
|
|
|
|
ret = -EEXIST;
|
|
down_write(&key_types_sem);
|
|
|
|
/* disallow key types with the same name */
|
|
list_for_each_entry(p, &key_types_list, link) {
|
|
if (strcmp(p->name, ktype->name) == 0)
|
|
goto out;
|
|
}
|
|
|
|
/* store the type */
|
|
list_add(&ktype->link, &key_types_list);
|
|
|
|
pr_notice("Key type %s registered\n", ktype->name);
|
|
ret = 0;
|
|
|
|
out:
|
|
up_write(&key_types_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(register_key_type);
|
|
|
|
/**
|
|
* unregister_key_type - Unregister a type of key.
|
|
* @ktype: The key type.
|
|
*
|
|
* Unregister a key type and mark all the extant keys of this type as dead.
|
|
* Those keys of this type are then destroyed to get rid of their payloads and
|
|
* they and their links will be garbage collected as soon as possible.
|
|
*/
|
|
void unregister_key_type(struct key_type *ktype)
|
|
{
|
|
down_write(&key_types_sem);
|
|
list_del_init(&ktype->link);
|
|
downgrade_write(&key_types_sem);
|
|
key_gc_keytype(ktype);
|
|
pr_notice("Key type %s unregistered\n", ktype->name);
|
|
up_read(&key_types_sem);
|
|
}
|
|
EXPORT_SYMBOL(unregister_key_type);
|
|
|
|
/*
|
|
* Initialise the key management state.
|
|
*/
|
|
void __init key_init(void)
|
|
{
|
|
/* allocate a slab in which we can store keys */
|
|
key_jar = kmem_cache_create("key_jar", sizeof(struct key),
|
|
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
|
|
|
|
/* add the special key types */
|
|
list_add_tail(&key_type_keyring.link, &key_types_list);
|
|
list_add_tail(&key_type_dead.link, &key_types_list);
|
|
list_add_tail(&key_type_user.link, &key_types_list);
|
|
list_add_tail(&key_type_logon.link, &key_types_list);
|
|
|
|
/* record the root user tracking */
|
|
rb_link_node(&root_key_user.node,
|
|
NULL,
|
|
&key_user_tree.rb_node);
|
|
|
|
rb_insert_color(&root_key_user.node,
|
|
&key_user_tree);
|
|
}
|