1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*
* Copyright (C) 2008 IBM Corporation
*
* Authors:
* Mimi Zohar <zohar@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* File: ima_iint.c
* - implements the IMA hooks: ima_inode_alloc, ima_inode_free
* - cache integrity information associated with an inode
* using a radix tree.
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/radix-tree.h>
#include "ima.h"
#define ima_iint_delete ima_inode_free
RADIX_TREE(ima_iint_store, GFP_ATOMIC);
DEFINE_SPINLOCK(ima_iint_lock);
static struct kmem_cache *iint_cache __read_mostly;
/* ima_iint_find_get - return the iint associated with an inode
*
* ima_iint_find_get gets a reference to the iint. Caller must
* remember to put the iint reference.
*/
struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
{
struct ima_iint_cache *iint;
rcu_read_lock();
iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode);
if (!iint)
goto out;
kref_get(&iint->refcount);
out:
rcu_read_unlock();
return iint;
}
/* Allocate memory for the iint associated with the inode
* from the iint_cache slab, initialize the iint, and
* insert it into the radix tree.
*
* On success return a pointer to the iint; on failure return NULL.
*/
struct ima_iint_cache *ima_iint_insert(struct inode *inode)
{
struct ima_iint_cache *iint = NULL;
int rc = 0;
if (!ima_initialized)
return iint;
iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
if (!iint)
return iint;
rc = radix_tree_preload(GFP_NOFS);
if (rc < 0)
goto out;
spin_lock(&ima_iint_lock);
rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint);
spin_unlock(&ima_iint_lock);
out:
if (rc < 0) {
kmem_cache_free(iint_cache, iint);
if (rc == -EEXIST) {
spin_lock(&ima_iint_lock);
iint = radix_tree_lookup(&ima_iint_store,
(unsigned long)inode);
spin_unlock(&ima_iint_lock);
} else
iint = NULL;
}
radix_tree_preload_end();
return iint;
}
/**
* ima_inode_alloc - allocate an iint associated with an inode
* @inode: pointer to the inode
*
* Return 0 on success, 1 on failure.
*/
int ima_inode_alloc(struct inode *inode)
{
struct ima_iint_cache *iint;
if (!ima_initialized)
return 0;
iint = ima_iint_insert(inode);
if (!iint)
return 1;
return 0;
}
/* ima_iint_find_insert_get - get the iint associated with an inode
*
* Most insertions are done at inode_alloc, except those allocated
* before late_initcall. When the iint does not exist, allocate it,
* initialize and insert it, and increment the iint refcount.
*
* (Can't initialize at security_initcall before any inodes are
* allocated, got to wait at least until proc_init.)
*
* Return the iint.
*/
struct ima_iint_cache *ima_iint_find_insert_get(struct inode *inode)
{
struct ima_iint_cache *iint = NULL;
iint = ima_iint_find_get(inode);
if (iint)
return iint;
iint = ima_iint_insert(inode);
if (iint)
kref_get(&iint->refcount);
return iint;
}
EXPORT_SYMBOL_GPL(ima_iint_find_insert_get);
/* iint_free - called when the iint refcount goes to zero */
void iint_free(struct kref *kref)
{
struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache,
refcount);
iint->version = 0;
iint->flags = 0UL;
if (iint->readcount != 0) {
printk(KERN_INFO "%s: readcount: %ld\n", __FUNCTION__,
iint->readcount);
iint->readcount = 0;
}
if (iint->writecount != 0) {
printk(KERN_INFO "%s: writecount: %ld\n", __FUNCTION__,
iint->writecount);
iint->writecount = 0;
}
if (iint->opencount != 0) {
printk(KERN_INFO "%s: opencount: %ld\n", __FUNCTION__,
iint->opencount);
iint->opencount = 0;
}
kref_set(&iint->refcount, 1);
kmem_cache_free(iint_cache, iint);
}
void iint_rcu_free(struct rcu_head *rcu_head)
{
struct ima_iint_cache *iint = container_of(rcu_head,
struct ima_iint_cache, rcu);
kref_put(&iint->refcount, iint_free);
}
/**
* ima_iint_delete - called on integrity_inode_free
* @inode: pointer to the inode
*
* Free the integrity information(iint) associated with an inode.
*/
void ima_iint_delete(struct inode *inode)
{
struct ima_iint_cache *iint;
if (!ima_initialized)
return;
spin_lock(&ima_iint_lock);
iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode);
spin_unlock(&ima_iint_lock);
if (iint)
call_rcu(&iint->rcu, iint_rcu_free);
}
static void init_once(void *foo)
{
struct ima_iint_cache *iint = foo;
memset(iint, 0, sizeof *iint);
iint->version = 0;
iint->flags = 0UL;
mutex_init(&iint->mutex);
iint->readcount = 0;
iint->writecount = 0;
iint->opencount = 0;
kref_set(&iint->refcount, 1);
}
void __init ima_iintcache_init(void)
{
iint_cache =
kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
SLAB_PANIC, init_once);
}
|
