1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2008 IBM Corporation
6 * Mimi Zohar <zohar@us.ibm.com>
8 * File: integrity_iint.c
9 * - implements the integrity hooks: integrity_inode_alloc,
10 * integrity_inode_free
11 * - cache integrity information associated with an inode
12 * using a rbtree tree.
14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/rbtree.h>
18 #include <linux/file.h>
19 #include <linux/uaccess.h>
20 #include <linux/security.h>
21 #include <linux/lsm_hooks.h>
22 #include "integrity.h"
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;
28 struct dentry *integrity_dir;
31 * __integrity_iint_find - return the iint associated with an inode
33 static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
35 struct integrity_iint_cache *iint;
36 struct rb_node *n = integrity_iint_tree.rb_node;
39 iint = rb_entry(n, struct integrity_iint_cache, rb_node);
41 if (inode < iint->inode)
43 else if (inode > iint->inode)
53 * integrity_iint_find - return the iint associated with an inode
55 struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
57 struct integrity_iint_cache *iint;
62 read_lock(&integrity_iint_lock);
63 iint = __integrity_iint_find(inode);
64 read_unlock(&integrity_iint_lock);
69 static void iint_free(struct integrity_iint_cache *iint)
71 kfree(iint->ima_hash);
72 iint->ima_hash = NULL;
75 iint->atomic_flags = 0UL;
76 iint->ima_file_status = INTEGRITY_UNKNOWN;
77 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
78 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
79 iint->ima_read_status = INTEGRITY_UNKNOWN;
80 iint->ima_creds_status = INTEGRITY_UNKNOWN;
81 iint->evm_status = INTEGRITY_UNKNOWN;
82 iint->measured_pcrs = 0;
83 kmem_cache_free(iint_cache, iint);
87 * integrity_inode_get - find or allocate an iint associated with an inode
88 * @inode: pointer to the inode
89 * @return: allocated iint
91 * Caller must lock i_mutex
93 struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
96 struct rb_node *node, *parent = NULL;
97 struct integrity_iint_cache *iint, *test_iint;
99 iint = integrity_iint_find(inode);
103 iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
107 write_lock(&integrity_iint_lock);
109 p = &integrity_iint_tree.rb_node;
112 test_iint = rb_entry(parent, struct integrity_iint_cache,
114 if (inode < test_iint->inode) {
116 } else if (inode > test_iint->inode) {
119 write_unlock(&integrity_iint_lock);
120 kmem_cache_free(iint_cache, iint);
126 node = &iint->rb_node;
127 inode->i_flags |= S_IMA;
128 rb_link_node(node, parent, p);
129 rb_insert_color(node, &integrity_iint_tree);
131 write_unlock(&integrity_iint_lock);
136 * integrity_inode_free - called on security_inode_free
137 * @inode: pointer to the inode
139 * Free the integrity information(iint) associated with an inode.
141 void integrity_inode_free(struct inode *inode)
143 struct integrity_iint_cache *iint;
148 write_lock(&integrity_iint_lock);
149 iint = __integrity_iint_find(inode);
150 rb_erase(&iint->rb_node, &integrity_iint_tree);
151 write_unlock(&integrity_iint_lock);
156 static void init_once(void *foo)
158 struct integrity_iint_cache *iint = (struct integrity_iint_cache *) foo;
160 memset(iint, 0, sizeof(*iint));
161 iint->ima_file_status = INTEGRITY_UNKNOWN;
162 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
163 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
164 iint->ima_read_status = INTEGRITY_UNKNOWN;
165 iint->ima_creds_status = INTEGRITY_UNKNOWN;
166 iint->evm_status = INTEGRITY_UNKNOWN;
167 mutex_init(&iint->mutex);
170 static int __init integrity_iintcache_init(void)
173 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
174 0, SLAB_PANIC, init_once);
177 DEFINE_LSM(integrity) = {
179 .init = integrity_iintcache_init,
180 .order = LSM_ORDER_LAST,
185 * integrity_kernel_read - read data from the file
187 * This is a function for reading file content instead of kernel_read().
188 * It does not perform locking checks to ensure it cannot be blocked.
189 * It does not perform security checks because it is irrelevant for IMA.
192 int integrity_kernel_read(struct file *file, loff_t offset,
193 void *addr, unsigned long count)
195 return __kernel_read(file, addr, count, &offset);
199 * integrity_load_keys - load integrity keys hook
201 * Hooks is called from init/main.c:kernel_init_freeable()
202 * when rootfs is ready
204 void __init integrity_load_keys(void)
208 if (!IS_ENABLED(CONFIG_IMA_LOAD_X509))
212 static int __init integrity_fs_init(void)
214 integrity_dir = securityfs_create_dir("integrity", NULL);
215 if (IS_ERR(integrity_dir)) {
216 int ret = PTR_ERR(integrity_dir);
219 pr_err("Unable to create integrity sysfs dir: %d\n",
221 integrity_dir = NULL;
228 late_initcall(integrity_fs_init)