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;
100 * The integrity's "iint_cache" is initialized at security_init(),
101 * unless it is not included in the ordered list of LSMs enabled
102 * on the boot command line.
105 panic("%s: lsm=integrity required.\n", __func__);
107 iint = integrity_iint_find(inode);
111 iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
115 write_lock(&integrity_iint_lock);
117 p = &integrity_iint_tree.rb_node;
120 test_iint = rb_entry(parent, struct integrity_iint_cache,
122 if (inode < test_iint->inode) {
124 } else if (inode > test_iint->inode) {
127 write_unlock(&integrity_iint_lock);
128 kmem_cache_free(iint_cache, iint);
134 node = &iint->rb_node;
135 inode->i_flags |= S_IMA;
136 rb_link_node(node, parent, p);
137 rb_insert_color(node, &integrity_iint_tree);
139 write_unlock(&integrity_iint_lock);
144 * integrity_inode_free - called on security_inode_free
145 * @inode: pointer to the inode
147 * Free the integrity information(iint) associated with an inode.
149 void integrity_inode_free(struct inode *inode)
151 struct integrity_iint_cache *iint;
156 write_lock(&integrity_iint_lock);
157 iint = __integrity_iint_find(inode);
158 rb_erase(&iint->rb_node, &integrity_iint_tree);
159 write_unlock(&integrity_iint_lock);
164 static void init_once(void *foo)
166 struct integrity_iint_cache *iint = (struct integrity_iint_cache *) foo;
168 memset(iint, 0, sizeof(*iint));
169 iint->ima_file_status = INTEGRITY_UNKNOWN;
170 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
171 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
172 iint->ima_read_status = INTEGRITY_UNKNOWN;
173 iint->ima_creds_status = INTEGRITY_UNKNOWN;
174 iint->evm_status = INTEGRITY_UNKNOWN;
175 mutex_init(&iint->mutex);
178 static int __init integrity_iintcache_init(void)
181 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
182 0, SLAB_PANIC, init_once);
185 DEFINE_LSM(integrity) = {
187 .init = integrity_iintcache_init,
192 * integrity_kernel_read - read data from the file
194 * This is a function for reading file content instead of kernel_read().
195 * It does not perform locking checks to ensure it cannot be blocked.
196 * It does not perform security checks because it is irrelevant for IMA.
199 int integrity_kernel_read(struct file *file, loff_t offset,
200 void *addr, unsigned long count)
202 return __kernel_read(file, addr, count, &offset);
206 * integrity_load_keys - load integrity keys hook
208 * Hooks is called from init/main.c:kernel_init_freeable()
209 * when rootfs is ready
211 void __init integrity_load_keys(void)
215 if (!IS_ENABLED(CONFIG_IMA_LOAD_X509))
219 static int __init integrity_fs_init(void)
221 integrity_dir = securityfs_create_dir("integrity", NULL);
222 if (IS_ERR(integrity_dir)) {
223 int ret = PTR_ERR(integrity_dir);
226 pr_err("Unable to create integrity sysfs dir: %d\n",
228 integrity_dir = NULL;
235 late_initcall(integrity_fs_init)