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->ima_file_status = INTEGRITY_UNKNOWN;
78 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
79 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
80 iint->ima_read_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)
121 node = &iint->rb_node;
122 inode->i_flags |= S_IMA;
123 rb_link_node(node, parent, p);
124 rb_insert_color(node, &integrity_iint_tree);
126 write_unlock(&integrity_iint_lock);
131 * integrity_inode_free - called on security_inode_free
132 * @inode: pointer to the inode
134 * Free the integrity information(iint) associated with an inode.
136 void integrity_inode_free(struct inode *inode)
138 struct integrity_iint_cache *iint;
143 write_lock(&integrity_iint_lock);
144 iint = __integrity_iint_find(inode);
145 rb_erase(&iint->rb_node, &integrity_iint_tree);
146 write_unlock(&integrity_iint_lock);
151 static void init_once(void *foo)
153 struct integrity_iint_cache *iint = foo;
155 memset(iint, 0, sizeof(*iint));
158 iint->ima_file_status = INTEGRITY_UNKNOWN;
159 iint->ima_mmap_status = INTEGRITY_UNKNOWN;
160 iint->ima_bprm_status = INTEGRITY_UNKNOWN;
161 iint->ima_read_status = INTEGRITY_UNKNOWN;
162 iint->evm_status = INTEGRITY_UNKNOWN;
163 iint->measured_pcrs = 0;
166 static int __init integrity_iintcache_init(void)
169 kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
170 0, SLAB_PANIC, init_once);
173 security_initcall(integrity_iintcache_init);
177 * integrity_kernel_read - read data from the file
179 * This is a function for reading file content instead of kernel_read().
180 * It does not perform locking checks to ensure it cannot be blocked.
181 * It does not perform security checks because it is irrelevant for IMA.
184 int integrity_kernel_read(struct file *file, loff_t offset,
185 char *addr, unsigned long count)
188 char __user *buf = (char __user *)addr;
191 if (!(file->f_mode & FMODE_READ))
196 ret = __vfs_read(file, buf, count, &offset);
203 * integrity_read_file - read entire file content into the buffer
205 * This is function opens a file, allocates the buffer of required
206 * size, read entire file content to the buffer and closes the file
208 * It is used only by init code.
211 int __init integrity_read_file(const char *path, char **data)
221 file = filp_open(path, O_RDONLY, 0);
224 pr_err("Unable to open file: %s (%d)", path, rc);
228 size = i_size_read(file_inode(file));
232 buf = kmalloc(size, GFP_KERNEL);
238 rc = integrity_kernel_read(file, 0, buf, size);
252 * integrity_load_keys - load integrity keys hook
254 * Hooks is called from init/main.c:kernel_init_freeable()
255 * when rootfs is ready
257 void __init integrity_load_keys(void)