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1d9b7d97d6
Cause an attempt to add a duplicate non-updateable key (such as a keyring) to a keyring to discard the extant copy in favour of the new one rather than failing with EEXIST: # do the test in an empty session keyctl session # create a new keyring called "a" and attach to session keyctl newring a @s # create another new keyring called "a" and attach to session, # displacing the keyring added by the second command: keyctl newring a @s Without this patch, the third command will fail. For updateable keys (such as those of "user" type), the update method will still be called rather than a new key being created. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1029 lines
24 KiB
C
1029 lines
24 KiB
C
/* key.c: basic authentication token and access key management
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*
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* Copyright (C) 2004-6 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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.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/err.h>
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#include "internal.h"
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static kmem_cache_t *key_jar;
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static key_serial_t key_serial_next = 3;
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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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static LIST_HEAD(key_types_list);
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static DECLARE_RWSEM(key_types_sem);
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static void key_cleanup(void *data);
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static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL);
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/* we serialise key instantiation and link */
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DECLARE_RWSEM(key_construction_sem);
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/* any key who's type gets unegistered will be re-typed to this */
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static struct key_type key_type_dead = {
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.name = "dead",
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};
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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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/*
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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(uid_t uid)
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{
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struct key_user *candidate = NULL, *user;
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struct rb_node *parent = NULL;
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struct rb_node **p;
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try_again:
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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 < user->uid)
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p = &(*p)->rb_left;
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else if (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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atomic_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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INIT_LIST_HEAD(&candidate->consq);
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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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atomic_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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} /* end key_user_lookup() */
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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 (atomic_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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} /* end key_user_put() */
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/*****************************************************************************/
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/*
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* insert a key with a fixed serial number
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*/
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static void __init __key_insert_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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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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BUG();
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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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} /* end __key_insert_serial() */
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/*****************************************************************************/
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/*
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* assign a key the next unique serial number
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* - we work through all the serial numbers between 2 and 2^31-1 in turn and
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* then wrap
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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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spin_lock(&key_serial_lock);
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/* propose a likely serial number and look for a hole for it in the
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* serial number tree */
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key->serial = key_serial_next;
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if (key->serial < 3)
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key->serial = 3;
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key_serial_next = key->serial + 1;
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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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goto insert_here;
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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 = key_serial_next;
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if (key->serial < 2)
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key->serial = 2;
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key_serial_next = key->serial + 1;
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if (!parent->rb_parent)
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p = &key_serial_tree.rb_node;
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else if (parent->rb_parent->rb_left == parent)
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p = &parent->rb_parent->rb_left;
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else
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p = &parent->rb_parent->rb_right;
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parent = rb_next(parent);
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if (!parent)
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break;
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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 insert_here;
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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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insert_here:
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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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} /* end key_alloc_serial() */
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/*****************************************************************************/
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/*
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* allocate a key of the specified type
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* - update the user's quota to reflect the existence of the key
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* - called from a key-type operation with key_types_sem read-locked by
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* key_create_or_update()
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* - this prevents unregistration of the key type
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* - upon return the key is as yet uninstantiated; the caller needs to either
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* instantiate the key or discard it before returning
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*/
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struct key *key_alloc(struct key_type *type, const char *desc,
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uid_t uid, gid_t gid, key_perm_t perm,
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int not_in_quota)
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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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desclen = strlen(desc) + 1;
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quotalen = desclen + 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 (!not_in_quota) {
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spin_lock(&user->lock);
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if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
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user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
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)
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goto no_quota;
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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_alloc(key_jar, SLAB_KERNEL);
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if (!key)
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goto no_memory_2;
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if (desc) {
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key->description = kmalloc(desclen, GFP_KERNEL);
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if (!key->description)
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goto no_memory_3;
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memcpy(key->description, desc, desclen);
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}
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atomic_set(&key->usage, 1);
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init_rwsem(&key->sem);
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key->type = type;
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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->flags = 0;
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key->expiry = 0;
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key->payload.data = NULL;
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key->security = NULL;
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if (!not_in_quota)
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key->flags |= 1 << KEY_FLAG_IN_QUOTA;
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memset(&key->type_data, 0, sizeof(key->type_data));
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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);
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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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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 (!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 (!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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} /* end key_alloc() */
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EXPORT_SYMBOL(key_alloc);
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/*****************************************************************************/
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/*
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* reserve an amount of quota for the key's payload
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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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spin_lock(&key->user->lock);
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if (delta > 0 &&
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key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES
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) {
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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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} /* end key_payload_reserve() */
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EXPORT_SYMBOL(key_payload_reserve);
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/*****************************************************************************/
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/*
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* instantiate a key and link it into the target keyring atomically
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* - called with the target keyring's semaphore writelocked
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*/
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static int __key_instantiate_and_link(struct key *key,
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const void *data,
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size_t datalen,
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struct key *keyring,
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struct key *instkey)
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{
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int ret, awaken;
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key_check(key);
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key_check(keyring);
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awaken = 0;
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ret = -EBUSY;
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down_write(&key_construction_sem);
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/* can't instantiate twice */
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if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
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/* instantiate the key */
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ret = key->type->instantiate(key, data, datalen);
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if (ret == 0) {
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/* mark the key as being instantiated */
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atomic_inc(&key->user->nikeys);
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set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
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if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
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awaken = 1;
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/* and link it into the destination keyring */
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if (keyring)
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ret = __key_link(keyring, key);
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/* disable the authorisation key */
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if (instkey)
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key_revoke(instkey);
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}
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}
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up_write(&key_construction_sem);
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/* wake up anyone waiting for a key to be constructed */
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if (awaken)
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wake_up_all(&request_key_conswq);
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return ret;
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} /* end __key_instantiate_and_link() */
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/*****************************************************************************/
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/*
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* instantiate a key and link it into the target keyring atomically
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*/
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int key_instantiate_and_link(struct key *key,
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const void *data,
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size_t datalen,
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struct key *keyring,
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struct key *instkey)
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{
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int ret;
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if (keyring)
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down_write(&keyring->sem);
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ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey);
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if (keyring)
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up_write(&keyring->sem);
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return ret;
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} /* end key_instantiate_and_link() */
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|
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EXPORT_SYMBOL(key_instantiate_and_link);
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|
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/*****************************************************************************/
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/*
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* negatively instantiate a key and link it into the target keyring atomically
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*/
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int key_negate_and_link(struct key *key,
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unsigned timeout,
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struct key *keyring,
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struct key *instkey)
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{
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struct timespec now;
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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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awaken = 0;
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ret = -EBUSY;
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|
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if (keyring)
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down_write(&keyring->sem);
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|
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down_write(&key_construction_sem);
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|
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/* can't instantiate twice */
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if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
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/* mark the key as being negatively instantiated */
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atomic_inc(&key->user->nikeys);
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set_bit(KEY_FLAG_NEGATIVE, &key->flags);
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set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
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now = current_kernel_time();
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key->expiry = now.tv_sec + timeout;
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|
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if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
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awaken = 1;
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|
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ret = 0;
|
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|
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/* and link it into the destination keyring */
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if (keyring)
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ret = __key_link(keyring, key);
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|
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/* disable the authorisation key */
|
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if (instkey)
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key_revoke(instkey);
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}
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|
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up_write(&key_construction_sem);
|
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|
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if (keyring)
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up_write(&keyring->sem);
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|
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/* wake up anyone waiting for a key to be constructed */
|
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if (awaken)
|
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wake_up_all(&request_key_conswq);
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|
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return ret;
|
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|
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} /* end key_negate_and_link() */
|
|
|
|
EXPORT_SYMBOL(key_negate_and_link);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* do cleaning up in process context so that we don't have to disable
|
|
* interrupts all over the place
|
|
*/
|
|
static void key_cleanup(void *data)
|
|
{
|
|
struct rb_node *_n;
|
|
struct key *key;
|
|
|
|
go_again:
|
|
/* look for a dead key in the tree */
|
|
spin_lock(&key_serial_lock);
|
|
|
|
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
|
|
key = rb_entry(_n, struct key, serial_node);
|
|
|
|
if (atomic_read(&key->usage) == 0)
|
|
goto found_dead_key;
|
|
}
|
|
|
|
spin_unlock(&key_serial_lock);
|
|
return;
|
|
|
|
found_dead_key:
|
|
/* we found a dead key - once we've removed it from the tree, we can
|
|
* drop the lock */
|
|
rb_erase(&key->serial_node, &key_serial_tree);
|
|
spin_unlock(&key_serial_lock);
|
|
|
|
key_check(key);
|
|
|
|
security_key_free(key);
|
|
|
|
/* deal with the user's key tracking and quota */
|
|
if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
|
|
spin_lock(&key->user->lock);
|
|
key->user->qnkeys--;
|
|
key->user->qnbytes -= key->quotalen;
|
|
spin_unlock(&key->user->lock);
|
|
}
|
|
|
|
atomic_dec(&key->user->nkeys);
|
|
if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
|
|
atomic_dec(&key->user->nikeys);
|
|
|
|
key_user_put(key->user);
|
|
|
|
/* now throw away the key memory */
|
|
if (key->type->destroy)
|
|
key->type->destroy(key);
|
|
|
|
kfree(key->description);
|
|
|
|
#ifdef KEY_DEBUGGING
|
|
key->magic = KEY_DEBUG_MAGIC_X;
|
|
#endif
|
|
kmem_cache_free(key_jar, key);
|
|
|
|
/* there may, of course, be more than one key to destroy */
|
|
goto go_again;
|
|
|
|
} /* end key_cleanup() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* dispose of a reference to a key
|
|
* - when all the references are gone, we schedule the cleanup task to come and
|
|
* pull it out of the tree in definite process context
|
|
*/
|
|
void key_put(struct key *key)
|
|
{
|
|
if (key) {
|
|
key_check(key);
|
|
|
|
if (atomic_dec_and_test(&key->usage))
|
|
schedule_work(&key_cleanup_task);
|
|
}
|
|
|
|
} /* end key_put() */
|
|
|
|
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:
|
|
/* pretend it doesn't exist if it's dead */
|
|
if (atomic_read(&key->usage) == 0 ||
|
|
test_bit(KEY_FLAG_DEAD, &key->flags) ||
|
|
key->type == &key_type_dead)
|
|
goto not_found;
|
|
|
|
/* this races with key_put(), but that doesn't matter since key_put()
|
|
* doesn't actually change the key
|
|
*/
|
|
atomic_inc(&key->usage);
|
|
|
|
error:
|
|
spin_unlock(&key_serial_lock);
|
|
return key;
|
|
|
|
} /* end key_lookup() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* find and lock the specified key type against removal
|
|
* - we return with the sem readlocked
|
|
*/
|
|
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;
|
|
|
|
} /* end key_type_lookup() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* unlock a key type
|
|
*/
|
|
void key_type_put(struct key_type *ktype)
|
|
{
|
|
up_read(&key_types_sem);
|
|
|
|
} /* end key_type_put() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* attempt to update an existing key
|
|
* - the key has an incremented refcount
|
|
* - we need to put the key if we get an error
|
|
*/
|
|
static inline key_ref_t __key_update(key_ref_t key_ref,
|
|
const void *payload, size_t plen)
|
|
{
|
|
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_WRITE);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
ret = -EEXIST;
|
|
if (!key->type->update)
|
|
goto error;
|
|
|
|
down_write(&key->sem);
|
|
|
|
ret = key->type->update(key, payload, plen);
|
|
if (ret == 0)
|
|
/* updating a negative key instantiates it */
|
|
clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
|
|
|
|
up_write(&key->sem);
|
|
|
|
if (ret < 0)
|
|
goto error;
|
|
out:
|
|
return key_ref;
|
|
|
|
error:
|
|
key_put(key);
|
|
key_ref = ERR_PTR(ret);
|
|
goto out;
|
|
|
|
} /* end __key_update() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* search the specified keyring for a key of the same description; if one is
|
|
* found, update it, otherwise add a new one
|
|
*/
|
|
key_ref_t key_create_or_update(key_ref_t keyring_ref,
|
|
const char *type,
|
|
const char *description,
|
|
const void *payload,
|
|
size_t plen,
|
|
int not_in_quota)
|
|
{
|
|
struct key_type *ktype;
|
|
struct key *keyring, *key = NULL;
|
|
key_perm_t perm;
|
|
key_ref_t key_ref;
|
|
int ret;
|
|
|
|
/* look up the key type to see if it's one of the registered kernel
|
|
* types */
|
|
ktype = key_type_lookup(type);
|
|
if (IS_ERR(ktype)) {
|
|
key_ref = ERR_PTR(-ENODEV);
|
|
goto error;
|
|
}
|
|
|
|
key_ref = ERR_PTR(-EINVAL);
|
|
if (!ktype->match || !ktype->instantiate)
|
|
goto error_2;
|
|
|
|
keyring = key_ref_to_ptr(keyring_ref);
|
|
|
|
key_check(keyring);
|
|
|
|
down_write(&keyring->sem);
|
|
|
|
/* if we're going to allocate a new key, we're going to have
|
|
* to modify the keyring */
|
|
ret = key_permission(keyring_ref, KEY_WRITE);
|
|
if (ret < 0) {
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_3;
|
|
}
|
|
|
|
/* 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 (ktype->update) {
|
|
key_ref = __keyring_search_one(keyring_ref, ktype, description,
|
|
0);
|
|
if (!IS_ERR(key_ref))
|
|
goto found_matching_key;
|
|
}
|
|
|
|
/* decide on the permissions we want */
|
|
perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
|
|
perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
|
|
|
|
if (ktype->read)
|
|
perm |= KEY_POS_READ | KEY_USR_READ;
|
|
|
|
if (ktype == &key_type_keyring || ktype->update)
|
|
perm |= KEY_USR_WRITE;
|
|
|
|
/* allocate a new key */
|
|
key = key_alloc(ktype, description, current->fsuid, current->fsgid,
|
|
perm, not_in_quota);
|
|
if (IS_ERR(key)) {
|
|
key_ref = ERR_PTR(PTR_ERR(key));
|
|
goto error_3;
|
|
}
|
|
|
|
/* instantiate it and link it into the target keyring */
|
|
ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
|
|
if (ret < 0) {
|
|
key_put(key);
|
|
key_ref = ERR_PTR(ret);
|
|
goto error_3;
|
|
}
|
|
|
|
key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
|
|
|
|
error_3:
|
|
up_write(&keyring->sem);
|
|
error_2:
|
|
key_type_put(ktype);
|
|
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
|
|
*/
|
|
up_write(&keyring->sem);
|
|
key_type_put(ktype);
|
|
|
|
key_ref = __key_update(key_ref, payload, plen);
|
|
goto error;
|
|
|
|
} /* end key_create_or_update() */
|
|
|
|
EXPORT_SYMBOL(key_create_or_update);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* update a key
|
|
*/
|
|
int key_update(key_ref_t key_ref, const void *payload, size_t plen)
|
|
{
|
|
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_WRITE);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
/* attempt to update it if supported */
|
|
ret = -EOPNOTSUPP;
|
|
if (key->type->update) {
|
|
down_write(&key->sem);
|
|
|
|
ret = key->type->update(key, payload, plen);
|
|
if (ret == 0)
|
|
/* updating a negative key instantiates it */
|
|
clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
|
|
|
|
up_write(&key->sem);
|
|
}
|
|
|
|
error:
|
|
return ret;
|
|
|
|
} /* end key_update() */
|
|
|
|
EXPORT_SYMBOL(key_update);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* revoke a key
|
|
*/
|
|
void key_revoke(struct key *key)
|
|
{
|
|
key_check(key);
|
|
|
|
/* make sure no one's trying to change or use the key when we mark
|
|
* it */
|
|
down_write(&key->sem);
|
|
set_bit(KEY_FLAG_REVOKED, &key->flags);
|
|
up_write(&key->sem);
|
|
|
|
} /* end key_revoke() */
|
|
|
|
EXPORT_SYMBOL(key_revoke);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* register a type of key
|
|
*/
|
|
int register_key_type(struct key_type *ktype)
|
|
{
|
|
struct key_type *p;
|
|
int ret;
|
|
|
|
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);
|
|
ret = 0;
|
|
|
|
out:
|
|
up_write(&key_types_sem);
|
|
return ret;
|
|
|
|
} /* end register_key_type() */
|
|
|
|
EXPORT_SYMBOL(register_key_type);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* unregister a type of key
|
|
*/
|
|
void unregister_key_type(struct key_type *ktype)
|
|
{
|
|
struct rb_node *_n;
|
|
struct key *key;
|
|
|
|
down_write(&key_types_sem);
|
|
|
|
/* withdraw the key type */
|
|
list_del_init(&ktype->link);
|
|
|
|
/* mark all the keys of this type dead */
|
|
spin_lock(&key_serial_lock);
|
|
|
|
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
|
|
key = rb_entry(_n, struct key, serial_node);
|
|
|
|
if (key->type == ktype)
|
|
key->type = &key_type_dead;
|
|
}
|
|
|
|
spin_unlock(&key_serial_lock);
|
|
|
|
/* make sure everyone revalidates their keys */
|
|
synchronize_rcu();
|
|
|
|
/* we should now be able to destroy the payloads of all the keys of
|
|
* this type with impunity */
|
|
spin_lock(&key_serial_lock);
|
|
|
|
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
|
|
key = rb_entry(_n, struct key, serial_node);
|
|
|
|
if (key->type == ktype) {
|
|
if (ktype->destroy)
|
|
ktype->destroy(key);
|
|
memset(&key->payload, 0xbd, sizeof(key->payload));
|
|
}
|
|
}
|
|
|
|
spin_unlock(&key_serial_lock);
|
|
up_write(&key_types_sem);
|
|
|
|
} /* end unregister_key_type() */
|
|
|
|
EXPORT_SYMBOL(unregister_key_type);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* initialise the key management stuff
|
|
*/
|
|
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, 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);
|
|
|
|
/* 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);
|
|
|
|
/* record root's user standard keyrings */
|
|
key_check(&root_user_keyring);
|
|
key_check(&root_session_keyring);
|
|
|
|
__key_insert_serial(&root_user_keyring);
|
|
__key_insert_serial(&root_session_keyring);
|
|
|
|
keyring_publish_name(&root_user_keyring);
|
|
keyring_publish_name(&root_session_keyring);
|
|
|
|
/* link the two root keyrings together */
|
|
key_link(&root_session_keyring, &root_user_keyring);
|
|
|
|
} /* end key_init() */
|