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f381c272 MZ |
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_SPINLOCK(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 | 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 | */ | |
59 | struct 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 | ||
73 | static void iint_free(struct integrity_iint_cache *iint) | |
74 | { | |
75 | iint->version = 0; | |
76 | iint->flags = 0UL; | |
77 | kmem_cache_free(iint_cache, iint); | |
78 | } | |
79 | ||
80 | /** | |
81 | * integrity_inode_alloc - allocate an iint associated with an inode | |
82 | * @inode: pointer to the inode | |
83 | */ | |
84 | int integrity_inode_alloc(struct inode *inode) | |
85 | { | |
86 | struct rb_node **p; | |
87 | struct rb_node *new_node, *parent = NULL; | |
88 | struct integrity_iint_cache *new_iint, *test_iint; | |
89 | int rc; | |
90 | ||
91 | new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS); | |
92 | if (!new_iint) | |
93 | return -ENOMEM; | |
94 | ||
95 | new_iint->inode = inode; | |
96 | new_node = &new_iint->rb_node; | |
97 | ||
98 | mutex_lock(&inode->i_mutex); /* i_flags */ | |
99 | spin_lock(&integrity_iint_lock); | |
100 | ||
101 | p = &integrity_iint_tree.rb_node; | |
102 | while (*p) { | |
103 | parent = *p; | |
104 | test_iint = rb_entry(parent, struct integrity_iint_cache, | |
105 | rb_node); | |
106 | rc = -EEXIST; | |
107 | if (inode < test_iint->inode) | |
108 | p = &(*p)->rb_left; | |
109 | else if (inode > test_iint->inode) | |
110 | p = &(*p)->rb_right; | |
111 | else | |
112 | goto out_err; | |
113 | } | |
114 | ||
115 | inode->i_flags |= S_IMA; | |
116 | rb_link_node(new_node, parent, p); | |
117 | rb_insert_color(new_node, &integrity_iint_tree); | |
118 | ||
119 | spin_unlock(&integrity_iint_lock); | |
120 | mutex_unlock(&inode->i_mutex); /* i_flags */ | |
121 | ||
122 | return 0; | |
123 | out_err: | |
124 | spin_unlock(&integrity_iint_lock); | |
125 | mutex_unlock(&inode->i_mutex); /* i_flags */ | |
126 | iint_free(new_iint); | |
127 | ||
128 | return rc; | |
129 | } | |
130 | ||
131 | /** | |
132 | * integrity_inode_free - called on security_inode_free | |
133 | * @inode: pointer to the inode | |
134 | * | |
135 | * Free the integrity information(iint) associated with an inode. | |
136 | */ | |
137 | void integrity_inode_free(struct inode *inode) | |
138 | { | |
139 | struct integrity_iint_cache *iint; | |
140 | ||
141 | if (!IS_IMA(inode)) | |
142 | return; | |
143 | ||
144 | spin_lock(&integrity_iint_lock); | |
145 | iint = __integrity_iint_find(inode); | |
146 | rb_erase(&iint->rb_node, &integrity_iint_tree); | |
147 | spin_unlock(&integrity_iint_lock); | |
148 | ||
149 | iint_free(iint); | |
150 | } | |
151 | ||
152 | static void init_once(void *foo) | |
153 | { | |
154 | struct integrity_iint_cache *iint = foo; | |
155 | ||
156 | memset(iint, 0, sizeof *iint); | |
157 | iint->version = 0; | |
158 | iint->flags = 0UL; | |
159 | mutex_init(&iint->mutex); | |
66dbc325 | 160 | iint->hmac_status = INTEGRITY_UNKNOWN; |
f381c272 MZ |
161 | } |
162 | ||
163 | static int __init integrity_iintcache_init(void) | |
164 | { | |
165 | iint_cache = | |
166 | kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), | |
167 | 0, SLAB_PANIC, init_once); | |
168 | iint_initialized = 1; | |
169 | return 0; | |
170 | } | |
171 | security_initcall(integrity_iintcache_init); |