Merge branch 'for-linville' of git://github.com/kvalo/ath6kl
[~shefty/rdma-dev.git] / security / integrity / iint.c
1 /*
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
24 static struct rb_root integrity_iint_tree = RB_ROOT;
25 static DEFINE_RWLOCK(integrity_iint_lock);
26 static struct kmem_cache *iint_cache __read_mostly;
27
28 int iint_initialized;
29
30 /*
31  * __integrity_iint_find - return the iint associated with an inode
32  */
33 static 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         while (n) {
39                 iint = rb_entry(n, struct integrity_iint_cache, rb_node);
40
41                 if (inode < iint->inode)
42                         n = n->rb_left;
43                 else if (inode > iint->inode)
44                         n = n->rb_right;
45                 else
46                         break;
47         }
48         if (!n)
49                 return NULL;
50
51         return iint;
52 }
53
54 /*
55  * integrity_iint_find - return the iint associated with an inode
56  */
57 struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
58 {
59         struct integrity_iint_cache *iint;
60
61         if (!IS_IMA(inode))
62                 return NULL;
63
64         read_lock(&integrity_iint_lock);
65         iint = __integrity_iint_find(inode);
66         read_unlock(&integrity_iint_lock);
67
68         return iint;
69 }
70
71 static void iint_free(struct integrity_iint_cache *iint)
72 {
73         iint->version = 0;
74         iint->flags = 0UL;
75         iint->ima_status = INTEGRITY_UNKNOWN;
76         iint->evm_status = INTEGRITY_UNKNOWN;
77         kmem_cache_free(iint_cache, iint);
78 }
79
80 /**
81  * integrity_inode_get - find or allocate an iint associated with an inode
82  * @inode: pointer to the inode
83  * @return: allocated iint
84  *
85  * Caller must lock i_mutex
86  */
87 struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
88 {
89         struct rb_node **p;
90         struct rb_node *node, *parent = NULL;
91         struct integrity_iint_cache *iint, *test_iint;
92
93         iint = integrity_iint_find(inode);
94         if (iint)
95                 return iint;
96
97         iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
98         if (!iint)
99                 return NULL;
100
101         write_lock(&integrity_iint_lock);
102
103         p = &integrity_iint_tree.rb_node;
104         while (*p) {
105                 parent = *p;
106                 test_iint = rb_entry(parent, struct integrity_iint_cache,
107                                      rb_node);
108                 if (inode < test_iint->inode)
109                         p = &(*p)->rb_left;
110                 else
111                         p = &(*p)->rb_right;
112         }
113
114         iint->inode = inode;
115         node = &iint->rb_node;
116         inode->i_flags |= S_IMA;
117         rb_link_node(node, parent, p);
118         rb_insert_color(node, &integrity_iint_tree);
119
120         write_unlock(&integrity_iint_lock);
121         return iint;
122 }
123
124 /**
125  * integrity_inode_free - called on security_inode_free
126  * @inode: pointer to the inode
127  *
128  * Free the integrity information(iint) associated with an inode.
129  */
130 void integrity_inode_free(struct inode *inode)
131 {
132         struct integrity_iint_cache *iint;
133
134         if (!IS_IMA(inode))
135                 return;
136
137         write_lock(&integrity_iint_lock);
138         iint = __integrity_iint_find(inode);
139         rb_erase(&iint->rb_node, &integrity_iint_tree);
140         write_unlock(&integrity_iint_lock);
141
142         iint_free(iint);
143 }
144
145 static void init_once(void *foo)
146 {
147         struct integrity_iint_cache *iint = foo;
148
149         memset(iint, 0, sizeof *iint);
150         iint->version = 0;
151         iint->flags = 0UL;
152         iint->ima_status = INTEGRITY_UNKNOWN;
153         iint->evm_status = INTEGRITY_UNKNOWN;
154 }
155
156 static int __init integrity_iintcache_init(void)
157 {
158         iint_cache =
159             kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
160                               0, SLAB_PANIC, init_once);
161         iint_initialized = 1;
162         return 0;
163 }
164 security_initcall(integrity_iintcache_init);