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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; | |
2fe5d6de | 77 | iint->ima_status = INTEGRITY_UNKNOWN; |
fb788d8b | 78 | iint->evm_status = INTEGRITY_UNKNOWN; |
f381c272 MZ |
79 | kmem_cache_free(iint_cache, iint); |
80 | } | |
81 | ||
82 | /** | |
bf2276d1 | 83 | * integrity_inode_get - find or allocate an iint associated with an inode |
f381c272 | 84 | * @inode: pointer to the inode |
bf2276d1 DK |
85 | * @return: allocated iint |
86 | * | |
87 | * Caller must lock i_mutex | |
f381c272 | 88 | */ |
bf2276d1 | 89 | struct integrity_iint_cache *integrity_inode_get(struct inode *inode) |
f381c272 MZ |
90 | { |
91 | struct rb_node **p; | |
bf2276d1 DK |
92 | struct rb_node *node, *parent = NULL; |
93 | struct integrity_iint_cache *iint, *test_iint; | |
f381c272 | 94 | |
bf2276d1 DK |
95 | iint = integrity_iint_find(inode); |
96 | if (iint) | |
97 | return iint; | |
f381c272 | 98 | |
bf2276d1 DK |
99 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
100 | if (!iint) | |
101 | return NULL; | |
f381c272 | 102 | |
f381c272 MZ |
103 | spin_lock(&integrity_iint_lock); |
104 | ||
105 | p = &integrity_iint_tree.rb_node; | |
106 | while (*p) { | |
107 | parent = *p; | |
108 | test_iint = rb_entry(parent, struct integrity_iint_cache, | |
109 | rb_node); | |
f381c272 MZ |
110 | if (inode < test_iint->inode) |
111 | p = &(*p)->rb_left; | |
f381c272 | 112 | else |
bf2276d1 | 113 | p = &(*p)->rb_right; |
f381c272 MZ |
114 | } |
115 | ||
bf2276d1 DK |
116 | iint->inode = inode; |
117 | node = &iint->rb_node; | |
f381c272 | 118 | inode->i_flags |= S_IMA; |
bf2276d1 DK |
119 | rb_link_node(node, parent, p); |
120 | rb_insert_color(node, &integrity_iint_tree); | |
f381c272 MZ |
121 | |
122 | spin_unlock(&integrity_iint_lock); | |
bf2276d1 | 123 | return iint; |
f381c272 MZ |
124 | } |
125 | ||
126 | /** | |
127 | * integrity_inode_free - called on security_inode_free | |
128 | * @inode: pointer to the inode | |
129 | * | |
130 | * Free the integrity information(iint) associated with an inode. | |
131 | */ | |
132 | void integrity_inode_free(struct inode *inode) | |
133 | { | |
134 | struct integrity_iint_cache *iint; | |
135 | ||
136 | if (!IS_IMA(inode)) | |
137 | return; | |
138 | ||
139 | spin_lock(&integrity_iint_lock); | |
140 | iint = __integrity_iint_find(inode); | |
141 | rb_erase(&iint->rb_node, &integrity_iint_tree); | |
142 | spin_unlock(&integrity_iint_lock); | |
143 | ||
144 | iint_free(iint); | |
145 | } | |
146 | ||
147 | static void init_once(void *foo) | |
148 | { | |
149 | struct integrity_iint_cache *iint = foo; | |
150 | ||
151 | memset(iint, 0, sizeof *iint); | |
152 | iint->version = 0; | |
153 | iint->flags = 0UL; | |
2fe5d6de | 154 | iint->ima_status = INTEGRITY_UNKNOWN; |
24e0198e | 155 | iint->evm_status = INTEGRITY_UNKNOWN; |
f381c272 MZ |
156 | } |
157 | ||
158 | static int __init integrity_iintcache_init(void) | |
159 | { | |
160 | iint_cache = | |
161 | kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), | |
162 | 0, SLAB_PANIC, init_once); | |
163 | iint_initialized = 1; | |
164 | return 0; | |
165 | } | |
166 | security_initcall(integrity_iintcache_init); |