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Mimi Zoharf381c272011-03-09 14:13:22 -05001/*
2 * Copyright (C) 2008 IBM Corporation
3 *
4 * Authors:
5 * Mimi Zohar <zohar@us.ibm.com>
6 *
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
10 * License.
11 *
12 * File: integrity_iint.c
13 * - implements the integrity hooks: integrity_inode_alloc,
14 * integrity_inode_free
15 * - cache integrity information associated with an inode
16 * using a rbtree tree.
17 */
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/spinlock.h>
21#include <linux/rbtree.h>
22#include "integrity.h"
23
24static struct rb_root integrity_iint_tree = RB_ROOT;
25static DEFINE_SPINLOCK(integrity_iint_lock);
26static struct kmem_cache *iint_cache __read_mostly;
27
28int iint_initialized;
29
30/*
31 * __integrity_iint_find - return the iint associated with an inode
32 */
33static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
34{
35 struct integrity_iint_cache *iint;
36 struct rb_node *n = integrity_iint_tree.rb_node;
37
38 assert_spin_locked(&integrity_iint_lock);
39
40 while (n) {
41 iint = rb_entry(n, struct integrity_iint_cache, rb_node);
42
43 if (inode < iint->inode)
44 n = n->rb_left;
45 else if (inode > iint->inode)
46 n = n->rb_right;
47 else
48 break;
49 }
50 if (!n)
51 return NULL;
52
53 return iint;
54}
55
56/*
57 * integrity_iint_find - return the iint associated with an inode
58 */
59struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
60{
61 struct integrity_iint_cache *iint;
62
63 if (!IS_IMA(inode))
64 return NULL;
65
66 spin_lock(&integrity_iint_lock);
67 iint = __integrity_iint_find(inode);
68 spin_unlock(&integrity_iint_lock);
69
70 return iint;
71}
72
73static void iint_free(struct integrity_iint_cache *iint)
74{
75 iint->version = 0;
76 iint->flags = 0UL;
Mimi Zohar2fe5d6d2012-02-13 10:15:05 -050077 iint->ima_status = INTEGRITY_UNKNOWN;
Dmitry Kasatkinfb788d82011-08-15 15:30:11 +030078 iint->evm_status = INTEGRITY_UNKNOWN;
Mimi Zoharf381c272011-03-09 14:13:22 -050079 kmem_cache_free(iint_cache, iint);
80}
81
82/**
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030083 * integrity_inode_get - find or allocate an iint associated with an inode
Mimi Zoharf381c272011-03-09 14:13:22 -050084 * @inode: pointer to the inode
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030085 * @return: allocated iint
86 *
87 * Caller must lock i_mutex
Mimi Zoharf381c272011-03-09 14:13:22 -050088 */
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030089struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
Mimi Zoharf381c272011-03-09 14:13:22 -050090{
91 struct rb_node **p;
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030092 struct rb_node *node, *parent = NULL;
93 struct integrity_iint_cache *iint, *test_iint;
Mimi Zoharf381c272011-03-09 14:13:22 -050094
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030095 iint = integrity_iint_find(inode);
96 if (iint)
97 return iint;
Mimi Zoharf381c272011-03-09 14:13:22 -050098
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +030099 iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
100 if (!iint)
101 return NULL;
Mimi Zoharf381c272011-03-09 14:13:22 -0500102
Mimi Zoharf381c272011-03-09 14:13:22 -0500103 spin_lock(&integrity_iint_lock);
104
105 p = &integrity_iint_tree.rb_node;
106 while (*p) {
107 parent = *p;
108 test_iint = rb_entry(parent, struct integrity_iint_cache,
109 rb_node);
Mimi Zoharf381c272011-03-09 14:13:22 -0500110 if (inode < test_iint->inode)
111 p = &(*p)->rb_left;
Mimi Zoharf381c272011-03-09 14:13:22 -0500112 else
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +0300113 p = &(*p)->rb_right;
Mimi Zoharf381c272011-03-09 14:13:22 -0500114 }
115
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +0300116 iint->inode = inode;
117 node = &iint->rb_node;
Mimi Zoharf381c272011-03-09 14:13:22 -0500118 inode->i_flags |= S_IMA;
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +0300119 rb_link_node(node, parent, p);
120 rb_insert_color(node, &integrity_iint_tree);
Mimi Zoharf381c272011-03-09 14:13:22 -0500121
122 spin_unlock(&integrity_iint_lock);
Dmitry Kasatkinbf2276d2011-10-19 12:04:40 +0300123 return iint;
Mimi Zoharf381c272011-03-09 14:13:22 -0500124}
125
126/**
127 * integrity_inode_free - called on security_inode_free
128 * @inode: pointer to the inode
129 *
130 * Free the integrity information(iint) associated with an inode.
131 */
132void integrity_inode_free(struct inode *inode)
133{
134 struct integrity_iint_cache *iint;
135
136 if (!IS_IMA(inode))
137 return;
138
139 spin_lock(&integrity_iint_lock);
140 iint = __integrity_iint_find(inode);
141 rb_erase(&iint->rb_node, &integrity_iint_tree);
142 spin_unlock(&integrity_iint_lock);
143
144 iint_free(iint);
145}
146
147static void init_once(void *foo)
148{
149 struct integrity_iint_cache *iint = foo;
150
151 memset(iint, 0, sizeof *iint);
152 iint->version = 0;
153 iint->flags = 0UL;
Mimi Zohar2fe5d6d2012-02-13 10:15:05 -0500154 iint->ima_status = INTEGRITY_UNKNOWN;
Dmitry Kasatkin24e01982011-05-06 11:34:17 +0300155 iint->evm_status = INTEGRITY_UNKNOWN;
Mimi Zoharf381c272011-03-09 14:13:22 -0500156}
157
158static int __init integrity_iintcache_init(void)
159{
160 iint_cache =
161 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
162 0, SLAB_PANIC, init_once);
163 iint_initialized = 1;
164 return 0;
165}
166security_initcall(integrity_iintcache_init);