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3323eec9 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: ima_iint.c | |
13 | * - implements the IMA hooks: ima_inode_alloc, ima_inode_free | |
14 | * - cache integrity information associated with an inode | |
15 | * using a radix tree. | |
16 | */ | |
17 | #include <linux/module.h> | |
18 | #include <linux/spinlock.h> | |
19 | #include <linux/radix-tree.h> | |
20 | #include "ima.h" | |
21 | ||
22 | #define ima_iint_delete ima_inode_free | |
23 | ||
24 | RADIX_TREE(ima_iint_store, GFP_ATOMIC); | |
25 | DEFINE_SPINLOCK(ima_iint_lock); | |
26 | ||
27 | static struct kmem_cache *iint_cache __read_mostly; | |
28 | ||
29 | /* ima_iint_find_get - return the iint associated with an inode | |
30 | * | |
31 | * ima_iint_find_get gets a reference to the iint. Caller must | |
32 | * remember to put the iint reference. | |
33 | */ | |
34 | struct ima_iint_cache *ima_iint_find_get(struct inode *inode) | |
35 | { | |
36 | struct ima_iint_cache *iint; | |
37 | ||
38 | rcu_read_lock(); | |
39 | iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode); | |
40 | if (!iint) | |
41 | goto out; | |
42 | kref_get(&iint->refcount); | |
43 | out: | |
44 | rcu_read_unlock(); | |
45 | return iint; | |
46 | } | |
47 | ||
9353384e EP |
48 | /** |
49 | * ima_inode_alloc - allocate an iint associated with an inode | |
50 | * @inode: pointer to the inode | |
3323eec9 | 51 | */ |
9353384e | 52 | int ima_inode_alloc(struct inode *inode) |
3323eec9 MZ |
53 | { |
54 | struct ima_iint_cache *iint = NULL; | |
55 | int rc = 0; | |
56 | ||
57 | if (!ima_initialized) | |
9353384e EP |
58 | return 0; |
59 | ||
c09c59e6 | 60 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
3323eec9 | 61 | if (!iint) |
9353384e | 62 | return -ENOMEM; |
3323eec9 | 63 | |
c09c59e6 | 64 | rc = radix_tree_preload(GFP_NOFS); |
3323eec9 MZ |
65 | if (rc < 0) |
66 | goto out; | |
67 | ||
68 | spin_lock(&ima_iint_lock); | |
69 | rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint); | |
70 | spin_unlock(&ima_iint_lock); | |
71 | out: | |
9353384e | 72 | if (rc < 0) |
3323eec9 | 73 | kmem_cache_free(iint_cache, iint); |
3323eec9 | 74 | |
9353384e | 75 | radix_tree_preload_end(); |
3323eec9 | 76 | |
9353384e | 77 | return rc; |
3323eec9 MZ |
78 | } |
79 | ||
80 | /* iint_free - called when the iint refcount goes to zero */ | |
81 | void iint_free(struct kref *kref) | |
82 | { | |
83 | struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache, | |
84 | refcount); | |
85 | iint->version = 0; | |
86 | iint->flags = 0UL; | |
1df9f0a7 MZ |
87 | if (iint->readcount != 0) { |
88 | printk(KERN_INFO "%s: readcount: %ld\n", __FUNCTION__, | |
89 | iint->readcount); | |
90 | iint->readcount = 0; | |
91 | } | |
92 | if (iint->writecount != 0) { | |
93 | printk(KERN_INFO "%s: writecount: %ld\n", __FUNCTION__, | |
94 | iint->writecount); | |
95 | iint->writecount = 0; | |
96 | } | |
97 | if (iint->opencount != 0) { | |
98 | printk(KERN_INFO "%s: opencount: %ld\n", __FUNCTION__, | |
99 | iint->opencount); | |
100 | iint->opencount = 0; | |
101 | } | |
3323eec9 MZ |
102 | kref_set(&iint->refcount, 1); |
103 | kmem_cache_free(iint_cache, iint); | |
104 | } | |
105 | ||
106 | void iint_rcu_free(struct rcu_head *rcu_head) | |
107 | { | |
108 | struct ima_iint_cache *iint = container_of(rcu_head, | |
109 | struct ima_iint_cache, rcu); | |
110 | kref_put(&iint->refcount, iint_free); | |
111 | } | |
112 | ||
113 | /** | |
114 | * ima_iint_delete - called on integrity_inode_free | |
115 | * @inode: pointer to the inode | |
116 | * | |
117 | * Free the integrity information(iint) associated with an inode. | |
118 | */ | |
119 | void ima_iint_delete(struct inode *inode) | |
120 | { | |
121 | struct ima_iint_cache *iint; | |
122 | ||
123 | if (!ima_initialized) | |
124 | return; | |
125 | spin_lock(&ima_iint_lock); | |
126 | iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode); | |
127 | spin_unlock(&ima_iint_lock); | |
128 | if (iint) | |
129 | call_rcu(&iint->rcu, iint_rcu_free); | |
130 | } | |
131 | ||
132 | static void init_once(void *foo) | |
133 | { | |
134 | struct ima_iint_cache *iint = foo; | |
135 | ||
136 | memset(iint, 0, sizeof *iint); | |
137 | iint->version = 0; | |
138 | iint->flags = 0UL; | |
139 | mutex_init(&iint->mutex); | |
140 | iint->readcount = 0; | |
141 | iint->writecount = 0; | |
1df9f0a7 | 142 | iint->opencount = 0; |
3323eec9 MZ |
143 | kref_set(&iint->refcount, 1); |
144 | } | |
145 | ||
932995f0 | 146 | void __init ima_iintcache_init(void) |
3323eec9 MZ |
147 | { |
148 | iint_cache = | |
149 | kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0, | |
150 | SLAB_PANIC, init_once); | |
151 | } |