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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 | ||
3323eec9 MZ |
22 | RADIX_TREE(ima_iint_store, GFP_ATOMIC); |
23 | DEFINE_SPINLOCK(ima_iint_lock); | |
24 | ||
25 | static struct kmem_cache *iint_cache __read_mostly; | |
26 | ||
27 | /* ima_iint_find_get - return the iint associated with an inode | |
28 | * | |
29 | * ima_iint_find_get gets a reference to the iint. Caller must | |
30 | * remember to put the iint reference. | |
31 | */ | |
32 | struct ima_iint_cache *ima_iint_find_get(struct inode *inode) | |
33 | { | |
34 | struct ima_iint_cache *iint; | |
35 | ||
36 | rcu_read_lock(); | |
37 | iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode); | |
38 | if (!iint) | |
39 | goto out; | |
40 | kref_get(&iint->refcount); | |
41 | out: | |
42 | rcu_read_unlock(); | |
43 | return iint; | |
44 | } | |
45 | ||
9353384e EP |
46 | /** |
47 | * ima_inode_alloc - allocate an iint associated with an inode | |
48 | * @inode: pointer to the inode | |
3323eec9 | 49 | */ |
9353384e | 50 | int ima_inode_alloc(struct inode *inode) |
3323eec9 MZ |
51 | { |
52 | struct ima_iint_cache *iint = NULL; | |
53 | int rc = 0; | |
54 | ||
c09c59e6 | 55 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
3323eec9 | 56 | if (!iint) |
9353384e | 57 | return -ENOMEM; |
3323eec9 | 58 | |
c09c59e6 | 59 | rc = radix_tree_preload(GFP_NOFS); |
3323eec9 MZ |
60 | if (rc < 0) |
61 | goto out; | |
62 | ||
63 | spin_lock(&ima_iint_lock); | |
64 | rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint); | |
65 | spin_unlock(&ima_iint_lock); | |
baac35c4 | 66 | radix_tree_preload_end(); |
3323eec9 | 67 | out: |
9353384e | 68 | if (rc < 0) |
3323eec9 | 69 | kmem_cache_free(iint_cache, iint); |
3323eec9 | 70 | |
9353384e | 71 | return rc; |
3323eec9 MZ |
72 | } |
73 | ||
74 | /* iint_free - called when the iint refcount goes to zero */ | |
75 | void iint_free(struct kref *kref) | |
76 | { | |
77 | struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache, | |
78 | refcount); | |
79 | iint->version = 0; | |
80 | iint->flags = 0UL; | |
1df9f0a7 MZ |
81 | if (iint->readcount != 0) { |
82 | printk(KERN_INFO "%s: readcount: %ld\n", __FUNCTION__, | |
83 | iint->readcount); | |
84 | iint->readcount = 0; | |
85 | } | |
86 | if (iint->writecount != 0) { | |
87 | printk(KERN_INFO "%s: writecount: %ld\n", __FUNCTION__, | |
88 | iint->writecount); | |
89 | iint->writecount = 0; | |
90 | } | |
91 | if (iint->opencount != 0) { | |
92 | printk(KERN_INFO "%s: opencount: %ld\n", __FUNCTION__, | |
93 | iint->opencount); | |
94 | iint->opencount = 0; | |
95 | } | |
3323eec9 MZ |
96 | kref_set(&iint->refcount, 1); |
97 | kmem_cache_free(iint_cache, iint); | |
98 | } | |
99 | ||
100 | void iint_rcu_free(struct rcu_head *rcu_head) | |
101 | { | |
102 | struct ima_iint_cache *iint = container_of(rcu_head, | |
103 | struct ima_iint_cache, rcu); | |
104 | kref_put(&iint->refcount, iint_free); | |
105 | } | |
106 | ||
107 | /** | |
85a17f55 | 108 | * ima_inode_free - called on security_inode_free |
3323eec9 MZ |
109 | * @inode: pointer to the inode |
110 | * | |
111 | * Free the integrity information(iint) associated with an inode. | |
112 | */ | |
85a17f55 | 113 | void ima_inode_free(struct inode *inode) |
3323eec9 MZ |
114 | { |
115 | struct ima_iint_cache *iint; | |
116 | ||
3323eec9 MZ |
117 | spin_lock(&ima_iint_lock); |
118 | iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode); | |
119 | spin_unlock(&ima_iint_lock); | |
120 | if (iint) | |
121 | call_rcu(&iint->rcu, iint_rcu_free); | |
122 | } | |
123 | ||
124 | static void init_once(void *foo) | |
125 | { | |
126 | struct ima_iint_cache *iint = foo; | |
127 | ||
128 | memset(iint, 0, sizeof *iint); | |
129 | iint->version = 0; | |
130 | iint->flags = 0UL; | |
131 | mutex_init(&iint->mutex); | |
132 | iint->readcount = 0; | |
133 | iint->writecount = 0; | |
1df9f0a7 | 134 | iint->opencount = 0; |
3323eec9 MZ |
135 | kref_set(&iint->refcount, 1); |
136 | } | |
137 | ||
54bb6552 | 138 | static int __init ima_iintcache_init(void) |
3323eec9 MZ |
139 | { |
140 | iint_cache = | |
141 | kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0, | |
142 | SLAB_PANIC, init_once); | |
54bb6552 | 143 | return 0; |
3323eec9 | 144 | } |
54bb6552 | 145 | security_initcall(ima_iintcache_init); |