2 * Copyright (C) 2008 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
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
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.
18 #include <linux/slab.h>
19 #include <linux/module.h>
20 #include <linux/spinlock.h>
21 #include <linux/rbtree.h>
22 #include <linux/file.h>
23 #include <linux/uaccess.h>
24 #include "integrity.h"
26 static struct rb_root integrity_iint_tree = RB_ROOT;
27 static DEFINE_RWLOCK(integrity_iint_lock);
28 static struct kmem_cache *iint_cache __read_mostly;
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)
55 * integrity_iint_find - return the iint associated with an inode
57 struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
59 struct integrity_iint_cache *iint;
64 read_lock(&integrity_iint_lock);
65 iint = __integrity_iint_find(inode);
66 read_unlock(&integrity_iint_lock);
71 static void iint_free(struct integrity_iint_cache *iint)
73 kfree(iint->ima_hash);
74 iint->ima_hash = NULL;
77 iint->atomic_flags = 0UL;
78 iint->ima_file_status = INTEGRITY_UNKNOWN;
79 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
80 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
81 iint->ima_read_status = INTEGRITY_UNKNOWN;
82 iint->evm_status = INTEGRITY_UNKNOWN;
83 iint->measured_pcrs = 0;
84 kmem_cache_free(iint_cache, iint);
88 * integrity_inode_get - find or allocate an iint associated with an inode
89 * @inode: pointer to the inode
90 * @return: allocated iint
92 * Caller must lock i_mutex
94 struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
97 struct rb_node *node, *parent = NULL;
98 struct integrity_iint_cache *iint, *test_iint;
100 iint = integrity_iint_find(inode);
104 iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
108 write_lock(&integrity_iint_lock);
110 p = &integrity_iint_tree.rb_node;
113 test_iint = rb_entry(parent, struct integrity_iint_cache,
115 if (inode < test_iint->inode)
122 node = &iint->rb_node;
123 inode->i_flags |= S_IMA;
124 rb_link_node(node, parent, p);
125 rb_insert_color(node, &integrity_iint_tree);
127 write_unlock(&integrity_iint_lock);
132 * integrity_inode_free - called on security_inode_free
133 * @inode: pointer to the inode
135 * Free the integrity information(iint) associated with an inode.
137 void integrity_inode_free(struct inode *inode)
139 struct integrity_iint_cache *iint;
144 write_lock(&integrity_iint_lock);
145 iint = __integrity_iint_find(inode);
146 rb_erase(&iint->rb_node, &integrity_iint_tree);
147 write_unlock(&integrity_iint_lock);
152 static void init_once(void *foo)
154 struct integrity_iint_cache *iint = foo;
156 memset(iint, 0, sizeof(*iint));
159 iint->atomic_flags = 0;
160 iint->ima_file_status = INTEGRITY_UNKNOWN;
161 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
162 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
163 iint->ima_read_status = INTEGRITY_UNKNOWN;
164 iint->evm_status = INTEGRITY_UNKNOWN;
165 iint->measured_pcrs = 0;
166 mutex_init(&iint->mutex);
169 static int __init integrity_iintcache_init(void)
172 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
173 0, SLAB_PANIC, init_once);
176 security_initcall(integrity_iintcache_init);
180 * integrity_kernel_read - read data from the file
182 * This is a function for reading file content instead of kernel_read().
183 * It does not perform locking checks to ensure it cannot be blocked.
184 * It does not perform security checks because it is irrelevant for IMA.
187 int integrity_kernel_read(struct file *file, loff_t offset,
188 char *addr, unsigned long count)
191 char __user *buf = (char __user *)addr;
194 if (!(file->f_mode & FMODE_READ))
199 ret = __vfs_read(file, buf, count, &offset);
206 * integrity_read_file - read entire file content into the buffer
208 * This is function opens a file, allocates the buffer of required
209 * size, read entire file content to the buffer and closes the file
211 * It is used only by init code.
214 int __init integrity_read_file(const char *path, char **data)
224 file = filp_open(path, O_RDONLY, 0);
227 pr_err("Unable to open file: %s (%d)", path, rc);
231 size = i_size_read(file_inode(file));
235 buf = kmalloc(size, GFP_KERNEL);
241 rc = integrity_kernel_read(file, 0, buf, size);
255 * integrity_load_keys - load integrity keys hook
257 * Hooks is called from init/main.c:kernel_init_freeable()
258 * when rootfs is ready
260 void __init integrity_load_keys(void)