tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
24static struct rb_root integrity_iint_tree = RB_ROOT;
25static DEFINE_RWLOCK(integrity_iint_lock);
26static struct kmem_cache *iint_cache __read_mostly;
27
28int iint_initialized;
29
30/*
31 * __integrity_iint_find - return the iint associated with an inode
32 */
33static 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 */
57struct 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
71static void iint_free(struct integrity_iint_cache *iint)
72{
73 kfree(iint->ima_hash);
74 iint->ima_hash = NULL;
75 iint->version = 0;
76 iint->flags = 0UL;
77 iint->ima_file_status = INTEGRITY_UNKNOWN;
78 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
79 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
80 iint->ima_module_status = INTEGRITY_UNKNOWN;
81 iint->evm_status = INTEGRITY_UNKNOWN;
82 kmem_cache_free(iint_cache, iint);
83}
84
85/**
86 * integrity_inode_get - find or allocate an iint associated with an inode
87 * @inode: pointer to the inode
88 * @return: allocated iint
89 *
90 * Caller must lock i_mutex
91 */
92struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
93{
94 struct rb_node **p;
95 struct rb_node *node, *parent = NULL;
96 struct integrity_iint_cache *iint, *test_iint;
97
98 iint = integrity_iint_find(inode);
99 if (iint)
100 return iint;
101
102 iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
103 if (!iint)
104 return NULL;
105
106 write_lock(&integrity_iint_lock);
107
108 p = &integrity_iint_tree.rb_node;
109 while (*p) {
110 parent = *p;
111 test_iint = rb_entry(parent, struct integrity_iint_cache,
112 rb_node);
113 if (inode < test_iint->inode)
114 p = &(*p)->rb_left;
115 else
116 p = &(*p)->rb_right;
117 }
118
119 iint->inode = inode;
120 node = &iint->rb_node;
121 inode->i_flags |= S_IMA;
122 rb_link_node(node, parent, p);
123 rb_insert_color(node, &integrity_iint_tree);
124
125 write_unlock(&integrity_iint_lock);
126 return iint;
127}
128
129/**
130 * integrity_inode_free - called on security_inode_free
131 * @inode: pointer to the inode
132 *
133 * Free the integrity information(iint) associated with an inode.
134 */
135void integrity_inode_free(struct inode *inode)
136{
137 struct integrity_iint_cache *iint;
138
139 if (!IS_IMA(inode))
140 return;
141
142 write_lock(&integrity_iint_lock);
143 iint = __integrity_iint_find(inode);
144 rb_erase(&iint->rb_node, &integrity_iint_tree);
145 write_unlock(&integrity_iint_lock);
146
147 iint_free(iint);
148}
149
150static void init_once(void *foo)
151{
152 struct integrity_iint_cache *iint = foo;
153
154 memset(iint, 0, sizeof(*iint));
155 iint->version = 0;
156 iint->flags = 0UL;
157 iint->ima_file_status = INTEGRITY_UNKNOWN;
158 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
159 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
160 iint->ima_module_status = INTEGRITY_UNKNOWN;
161 iint->evm_status = INTEGRITY_UNKNOWN;
162}
163
164static int __init integrity_iintcache_init(void)
165{
166 iint_cache =
167 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
168 0, SLAB_PANIC, init_once);
169 iint_initialized = 1;
170 return 0;
171}
172security_initcall(integrity_iintcache_init);