2 * Copyright (C) 2008 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation, version 2 of the
13 * - implements the IMA hooks: ima_inode_alloc, ima_inode_free
14 * - cache integrity information associated with an inode
15 * using a rbtree tree.
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/spinlock.h>
20 #include <linux/rbtree.h>
23 static struct rb_root ima_iint_tree = RB_ROOT;
24 static DEFINE_SPINLOCK(ima_iint_lock);
25 static struct kmem_cache *iint_cache __read_mostly;
27 int iint_initialized = 0;
30 * __ima_iint_find - return the iint associated with an inode
32 static struct ima_iint_cache *__ima_iint_find(struct inode *inode)
34 struct ima_iint_cache *iint;
35 struct rb_node *n = ima_iint_tree.rb_node;
37 assert_spin_locked(&ima_iint_lock);
40 iint = rb_entry(n, struct ima_iint_cache, rb_node);
42 if (inode < iint->inode)
44 else if (inode > iint->inode)
56 * ima_iint_find_get - return the iint associated with an inode
58 * ima_iint_find_get gets a reference to the iint. Caller must
59 * remember to put the iint reference.
61 struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
63 struct ima_iint_cache *iint;
65 spin_lock(&ima_iint_lock);
66 iint = __ima_iint_find(inode);
68 kref_get(&iint->refcount);
69 spin_unlock(&ima_iint_lock);
75 * ima_inode_alloc - allocate an iint associated with an inode
76 * @inode: pointer to the inode
78 int ima_inode_alloc(struct inode *inode)
81 struct rb_node *new_node, *parent = NULL;
82 struct ima_iint_cache *new_iint, *test_iint;
85 new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
89 new_iint->inode = inode;
90 new_node = &new_iint->rb_node;
92 spin_lock(&ima_iint_lock);
94 p = &ima_iint_tree.rb_node;
97 test_iint = rb_entry(parent, struct ima_iint_cache, rb_node);
100 if (inode < test_iint->inode)
102 else if (inode > test_iint->inode)
108 rb_link_node(new_node, parent, p);
109 rb_insert_color(new_node, &ima_iint_tree);
111 spin_unlock(&ima_iint_lock);
115 spin_unlock(&ima_iint_lock);
116 kref_put(&new_iint->refcount, iint_free);
120 /* iint_free - called when the iint refcount goes to zero */
121 void iint_free(struct kref *kref)
123 struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache,
127 if (iint->readcount != 0) {
128 printk(KERN_INFO "%s: readcount: %ld\n", __func__,
132 if (iint->writecount != 0) {
133 printk(KERN_INFO "%s: writecount: %ld\n", __func__,
135 iint->writecount = 0;
137 kref_init(&iint->refcount);
138 kmem_cache_free(iint_cache, iint);
142 * ima_inode_free - called on security_inode_free
143 * @inode: pointer to the inode
145 * Free the integrity information(iint) associated with an inode.
147 void ima_inode_free(struct inode *inode)
149 struct ima_iint_cache *iint;
151 spin_lock(&ima_iint_lock);
152 iint = __ima_iint_find(inode);
154 rb_erase(&iint->rb_node, &ima_iint_tree);
155 spin_unlock(&ima_iint_lock);
157 kref_put(&iint->refcount, iint_free);
160 static void init_once(void *foo)
162 struct ima_iint_cache *iint = foo;
164 memset(iint, 0, sizeof *iint);
167 mutex_init(&iint->mutex);
169 iint->writecount = 0;
170 kref_init(&iint->refcount);
173 static int __init ima_iintcache_init(void)
176 kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
177 SLAB_PANIC, init_once);
178 iint_initialized = 1;
181 security_initcall(ima_iintcache_init);