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Mimi Zohar3323eec92009-02-04 09:06:58 -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: ima_iint.c
13 * - implements the IMA hooks: ima_inode_alloc, ima_inode_free
14 * - cache integrity information associated with an inode
Eric Paris85491642010-10-25 14:41:18 -040015 * using a rbtree tree.
Mimi Zohar3323eec92009-02-04 09:06:58 -050016 */
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
Mimi Zohar3323eec92009-02-04 09:06:58 -050018#include <linux/module.h>
19#include <linux/spinlock.h>
Eric Paris85491642010-10-25 14:41:18 -040020#include <linux/rbtree.h>
Mimi Zohar3323eec92009-02-04 09:06:58 -050021#include "ima.h"
22
Eric Paris85491642010-10-25 14:41:18 -040023static struct rb_root ima_iint_tree = RB_ROOT;
24static DEFINE_SPINLOCK(ima_iint_lock);
Mimi Zohar3323eec92009-02-04 09:06:58 -050025static struct kmem_cache *iint_cache __read_mostly;
26
Mimi Zohare9505982010-08-31 09:38:51 -040027int iint_initialized = 0;
28
Eric Paris85491642010-10-25 14:41:18 -040029/*
30 * __ima_iint_find - return the iint associated with an inode
31 */
32static struct ima_iint_cache *__ima_iint_find(struct inode *inode)
33{
34 struct ima_iint_cache *iint;
35 struct rb_node *n = ima_iint_tree.rb_node;
36
37 assert_spin_locked(&ima_iint_lock);
38
39 while (n) {
40 iint = rb_entry(n, struct ima_iint_cache, rb_node);
41
42 if (inode < iint->inode)
43 n = n->rb_left;
44 else if (inode > iint->inode)
45 n = n->rb_right;
46 else
47 break;
48 }
49 if (!n)
50 return NULL;
51
52 return iint;
53}
54
55/*
Eric Paris64c62f02010-10-25 14:42:12 -040056 * ima_iint_find - return the iint associated with an inode
Mimi Zohar3323eec92009-02-04 09:06:58 -050057 */
Eric Paris64c62f02010-10-25 14:42:12 -040058struct ima_iint_cache *ima_iint_find(struct inode *inode)
Mimi Zohar3323eec92009-02-04 09:06:58 -050059{
60 struct ima_iint_cache *iint;
61
Eric Paris196f5182010-10-25 14:42:19 -040062 if (!IS_IMA(inode))
63 return NULL;
64
Eric Paris85491642010-10-25 14:41:18 -040065 spin_lock(&ima_iint_lock);
66 iint = __ima_iint_find(inode);
Eric Paris85491642010-10-25 14:41:18 -040067 spin_unlock(&ima_iint_lock);
68
Mimi Zohar3323eec92009-02-04 09:06:58 -050069 return iint;
70}
71
Eric Paris64c62f02010-10-25 14:42:12 -040072static void iint_free(struct ima_iint_cache *iint)
73{
74 iint->version = 0;
75 iint->flags = 0UL;
76 kmem_cache_free(iint_cache, iint);
77}
78
Eric Paris93533842009-12-04 15:47:52 -050079/**
80 * ima_inode_alloc - allocate an iint associated with an inode
81 * @inode: pointer to the inode
Mimi Zohar3323eec92009-02-04 09:06:58 -050082 */
Eric Paris93533842009-12-04 15:47:52 -050083int ima_inode_alloc(struct inode *inode)
Mimi Zohar3323eec92009-02-04 09:06:58 -050084{
Eric Paris85491642010-10-25 14:41:18 -040085 struct rb_node **p;
86 struct rb_node *new_node, *parent = NULL;
87 struct ima_iint_cache *new_iint, *test_iint;
88 int rc;
Mimi Zohar3323eec92009-02-04 09:06:58 -050089
Eric Paris85491642010-10-25 14:41:18 -040090 new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
91 if (!new_iint)
Eric Paris93533842009-12-04 15:47:52 -050092 return -ENOMEM;
Mimi Zohar3323eec92009-02-04 09:06:58 -050093
Eric Paris85491642010-10-25 14:41:18 -040094 new_iint->inode = inode;
95 new_node = &new_iint->rb_node;
Mimi Zohar3323eec92009-02-04 09:06:58 -050096
Eric Paris196f5182010-10-25 14:42:19 -040097 mutex_lock(&inode->i_mutex); /* i_flags */
Mimi Zohar3323eec92009-02-04 09:06:58 -050098 spin_lock(&ima_iint_lock);
Eric Paris93533842009-12-04 15:47:52 -050099
Eric Paris85491642010-10-25 14:41:18 -0400100 p = &ima_iint_tree.rb_node;
101 while (*p) {
102 parent = *p;
103 test_iint = rb_entry(parent, struct ima_iint_cache, rb_node);
104
105 rc = -EEXIST;
106 if (inode < test_iint->inode)
107 p = &(*p)->rb_left;
108 else if (inode > test_iint->inode)
109 p = &(*p)->rb_right;
110 else
111 goto out_err;
112 }
113
Eric Paris196f5182010-10-25 14:42:19 -0400114 inode->i_flags |= S_IMA;
Eric Paris85491642010-10-25 14:41:18 -0400115 rb_link_node(new_node, parent, p);
116 rb_insert_color(new_node, &ima_iint_tree);
117
118 spin_unlock(&ima_iint_lock);
Eric Paris196f5182010-10-25 14:42:19 -0400119 mutex_unlock(&inode->i_mutex); /* i_flags */
Eric Paris85491642010-10-25 14:41:18 -0400120
121 return 0;
122out_err:
123 spin_unlock(&ima_iint_lock);
Eric Paris196f5182010-10-25 14:42:19 -0400124 mutex_unlock(&inode->i_mutex); /* i_flags */
Eric Paris64c62f02010-10-25 14:42:12 -0400125 iint_free(new_iint);
Mimi Zohar3323eec92009-02-04 09:06:58 -0500126
Eric Paris64c62f02010-10-25 14:42:12 -0400127 return rc;
Mimi Zohar3323eec92009-02-04 09:06:58 -0500128}
129
Mimi Zohar3323eec92009-02-04 09:06:58 -0500130/**
Eric Paris85a17f52009-12-04 15:48:08 -0500131 * ima_inode_free - called on security_inode_free
Mimi Zohar3323eec92009-02-04 09:06:58 -0500132 * @inode: pointer to the inode
133 *
134 * Free the integrity information(iint) associated with an inode.
135 */
Eric Paris85a17f52009-12-04 15:48:08 -0500136void ima_inode_free(struct inode *inode)
Mimi Zohar3323eec92009-02-04 09:06:58 -0500137{
138 struct ima_iint_cache *iint;
139
Eric Paris196f5182010-10-25 14:42:19 -0400140 if (!IS_IMA(inode))
141 return;
142
Mimi Zohar3323eec92009-02-04 09:06:58 -0500143 spin_lock(&ima_iint_lock);
Eric Paris85491642010-10-25 14:41:18 -0400144 iint = __ima_iint_find(inode);
Eric Paris196f5182010-10-25 14:42:19 -0400145 rb_erase(&iint->rb_node, &ima_iint_tree);
Mimi Zohar3323eec92009-02-04 09:06:58 -0500146 spin_unlock(&ima_iint_lock);
Eric Paris64c62f02010-10-25 14:42:12 -0400147
Eric Paris64c62f02010-10-25 14:42:12 -0400148 iint_free(iint);
Mimi Zohar3323eec92009-02-04 09:06:58 -0500149}
150
151static void init_once(void *foo)
152{
153 struct ima_iint_cache *iint = foo;
154
155 memset(iint, 0, sizeof *iint);
156 iint->version = 0;
157 iint->flags = 0UL;
158 mutex_init(&iint->mutex);
Mimi Zohar3323eec92009-02-04 09:06:58 -0500159}
160
Eric Paris54bb6552009-12-09 15:29:01 -0500161static int __init ima_iintcache_init(void)
Mimi Zohar3323eec92009-02-04 09:06:58 -0500162{
163 iint_cache =
164 kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
165 SLAB_PANIC, init_once);
Mimi Zohare9505982010-08-31 09:38:51 -0400166 iint_initialized = 1;
Eric Paris54bb6552009-12-09 15:29:01 -0500167 return 0;
Mimi Zohar3323eec92009-02-04 09:06:58 -0500168}
Eric Paris54bb6552009-12-09 15:29:01 -0500169security_initcall(ima_iintcache_init);