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