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
|
/*
* 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/slab.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/radix-tree.h>
#include "ima.h"
RADIX_TREE(ima_iint_store, GFP_ATOMIC);
DEFINE_SPINLOCK(ima_iint_lock);
static struct kmem_cache *iint_cache __read_mostly;
int iint_initialized = 0;
/* 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;
}
/**
* ima_inode_alloc - allocate an iint associated with an inode
* @inode: pointer to the inode
*/
int ima_inode_alloc(struct inode *inode)
{
struct ima_iint_cache *iint = NULL;
int rc = 0;
iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
if (!iint)
return -ENOMEM;
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);
radix_tree_preload_end();
out:
if (rc < 0)
kmem_cache_free(iint_cache, iint);
return rc;
}
/* 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", __func__,
iint->readcount);
iint->readcount = 0;
}
if (iint->writecount != 0) {
printk(KERN_INFO "%s: writecount: %ld\n", __func__,
iint->writecount);
iint->writecount = 0;
}
if (iint->opencount != 0) {
printk(KERN_INFO "%s: opencount: %ld\n", __func__,
iint->opencount);
iint->opencount = 0;
}
kref_init(&iint->refcount);
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_inode_free - called on security_inode_free
* @inode: pointer to the inode
*
* Free the integrity information(iint) associated with an inode.
*/
void ima_inode_free(struct inode *inode)
{
struct ima_iint_cache *iint;
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_init(&iint->refcount);
}
static int __init ima_iintcache_init(void)
{
iint_cache =
kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
SLAB_PANIC, init_once);
iint_initialized = 1;
return 0;
}
security_initcall(ima_iintcache_init);
|
