Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 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> |
Dmitry Kasatkin | e3c4abb | 2014-11-05 17:01:12 +0200 | [diff] [blame] | 22 | #include <linux/file.h> |
| 23 | #include <linux/uaccess.h> |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 24 | #include "integrity.h" |
| 25 | |
| 26 | static struct rb_root integrity_iint_tree = RB_ROOT; |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 27 | static DEFINE_RWLOCK(integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 28 | static struct kmem_cache *iint_cache __read_mostly; |
| 29 | |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 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 | |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 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 | |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 64 | read_lock(&integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 65 | iint = __integrity_iint_find(inode); |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 66 | read_unlock(&integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 67 | |
| 68 | return iint; |
| 69 | } |
| 70 | |
| 71 | static void iint_free(struct integrity_iint_cache *iint) |
| 72 | { |
Dmitry Kasatkin | a35c3fb | 2013-04-25 10:44:04 +0300 | [diff] [blame] | 73 | kfree(iint->ima_hash); |
| 74 | iint->ima_hash = NULL; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 75 | iint->version = 0; |
| 76 | iint->flags = 0UL; |
Mimi Zohar | d79d72e | 2012-12-03 17:08:11 -0500 | [diff] [blame] | 77 | iint->ima_file_status = INTEGRITY_UNKNOWN; |
| 78 | iint->ima_mmap_status = INTEGRITY_UNKNOWN; |
| 79 | iint->ima_bprm_status = INTEGRITY_UNKNOWN; |
| 80 | iint->ima_module_status = INTEGRITY_UNKNOWN; |
Dmitry Kasatkin | fb788d8 | 2011-08-15 15:30:11 +0300 | [diff] [blame] | 81 | iint->evm_status = INTEGRITY_UNKNOWN; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 82 | kmem_cache_free(iint_cache, iint); |
| 83 | } |
| 84 | |
| 85 | /** |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 86 | * integrity_inode_get - find or allocate an iint associated with an inode |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 87 | * @inode: pointer to the inode |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 88 | * @return: allocated iint |
| 89 | * |
| 90 | * Caller must lock i_mutex |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 91 | */ |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 92 | struct integrity_iint_cache *integrity_inode_get(struct inode *inode) |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 93 | { |
| 94 | struct rb_node **p; |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 95 | struct rb_node *node, *parent = NULL; |
| 96 | struct integrity_iint_cache *iint, *test_iint; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 97 | |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 98 | iint = integrity_iint_find(inode); |
| 99 | if (iint) |
| 100 | return iint; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 101 | |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 102 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
| 103 | if (!iint) |
| 104 | return NULL; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 105 | |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 106 | write_lock(&integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 107 | |
| 108 | p = &integrity_iint_tree.rb_node; |
| 109 | while (*p) { |
| 110 | parent = *p; |
| 111 | test_iint = rb_entry(parent, struct integrity_iint_cache, |
| 112 | rb_node); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 113 | if (inode < test_iint->inode) |
| 114 | p = &(*p)->rb_left; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 115 | else |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 116 | p = &(*p)->rb_right; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 117 | } |
| 118 | |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 119 | iint->inode = inode; |
| 120 | node = &iint->rb_node; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 121 | inode->i_flags |= S_IMA; |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 122 | rb_link_node(node, parent, p); |
| 123 | rb_insert_color(node, &integrity_iint_tree); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 124 | |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 125 | write_unlock(&integrity_iint_lock); |
Dmitry Kasatkin | bf2276d | 2011-10-19 12:04:40 +0300 | [diff] [blame] | 126 | return iint; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 127 | } |
| 128 | |
| 129 | /** |
| 130 | * integrity_inode_free - called on security_inode_free |
| 131 | * @inode: pointer to the inode |
| 132 | * |
| 133 | * Free the integrity information(iint) associated with an inode. |
| 134 | */ |
| 135 | void integrity_inode_free(struct inode *inode) |
| 136 | { |
| 137 | struct integrity_iint_cache *iint; |
| 138 | |
| 139 | if (!IS_IMA(inode)) |
| 140 | return; |
| 141 | |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 142 | write_lock(&integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 143 | iint = __integrity_iint_find(inode); |
| 144 | rb_erase(&iint->rb_node, &integrity_iint_tree); |
Dmitry Kasatkin | a10bf26 | 2012-02-08 14:15:42 -0500 | [diff] [blame] | 145 | write_unlock(&integrity_iint_lock); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 146 | |
| 147 | iint_free(iint); |
| 148 | } |
| 149 | |
| 150 | static void init_once(void *foo) |
| 151 | { |
| 152 | struct integrity_iint_cache *iint = foo; |
| 153 | |
Dmitry Kasatkin | 2bb930a | 2014-03-04 18:04:20 +0200 | [diff] [blame] | 154 | memset(iint, 0, sizeof(*iint)); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 155 | iint->version = 0; |
| 156 | iint->flags = 0UL; |
Mimi Zohar | d79d72e | 2012-12-03 17:08:11 -0500 | [diff] [blame] | 157 | iint->ima_file_status = INTEGRITY_UNKNOWN; |
| 158 | iint->ima_mmap_status = INTEGRITY_UNKNOWN; |
| 159 | iint->ima_bprm_status = INTEGRITY_UNKNOWN; |
| 160 | iint->ima_module_status = INTEGRITY_UNKNOWN; |
Dmitry Kasatkin | 24e0198 | 2011-05-06 11:34:17 +0300 | [diff] [blame] | 161 | iint->evm_status = INTEGRITY_UNKNOWN; |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 162 | } |
| 163 | |
| 164 | static int __init integrity_iintcache_init(void) |
| 165 | { |
| 166 | iint_cache = |
| 167 | kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), |
| 168 | 0, SLAB_PANIC, init_once); |
Mimi Zohar | f381c27 | 2011-03-09 14:13:22 -0500 | [diff] [blame] | 169 | return 0; |
| 170 | } |
| 171 | security_initcall(integrity_iintcache_init); |
Dmitry Kasatkin | e3c4abb | 2014-11-05 17:01:12 +0200 | [diff] [blame] | 172 | |
| 173 | |
| 174 | /* |
| 175 | * integrity_kernel_read - read data from the file |
| 176 | * |
| 177 | * This is a function for reading file content instead of kernel_read(). |
| 178 | * It does not perform locking checks to ensure it cannot be blocked. |
| 179 | * It does not perform security checks because it is irrelevant for IMA. |
| 180 | * |
| 181 | */ |
| 182 | int integrity_kernel_read(struct file *file, loff_t offset, |
| 183 | char *addr, unsigned long count) |
| 184 | { |
| 185 | mm_segment_t old_fs; |
| 186 | char __user *buf = (char __user *)addr; |
Dmitry Kasatkin | 6fb5032 | 2014-11-05 17:01:17 +0200 | [diff] [blame^] | 187 | ssize_t ret; |
Dmitry Kasatkin | e3c4abb | 2014-11-05 17:01:12 +0200 | [diff] [blame] | 188 | |
| 189 | if (!(file->f_mode & FMODE_READ)) |
| 190 | return -EBADF; |
| 191 | |
| 192 | old_fs = get_fs(); |
| 193 | set_fs(get_ds()); |
Dmitry Kasatkin | 6fb5032 | 2014-11-05 17:01:17 +0200 | [diff] [blame^] | 194 | ret = __vfs_read(file, buf, count, &offset); |
Dmitry Kasatkin | e3c4abb | 2014-11-05 17:01:12 +0200 | [diff] [blame] | 195 | set_fs(old_fs); |
Dmitry Kasatkin | 6fb5032 | 2014-11-05 17:01:17 +0200 | [diff] [blame^] | 196 | |
Dmitry Kasatkin | e3c4abb | 2014-11-05 17:01:12 +0200 | [diff] [blame] | 197 | return ret; |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * integrity_read_file - read entire file content into the buffer |
| 202 | * |
| 203 | * This is function opens a file, allocates the buffer of required |
| 204 | * size, read entire file content to the buffer and closes the file |
| 205 | * |
| 206 | * It is used only by init code. |
| 207 | * |
| 208 | */ |
| 209 | int __init integrity_read_file(const char *path, char **data) |
| 210 | { |
| 211 | struct file *file; |
| 212 | loff_t size; |
| 213 | char *buf; |
| 214 | int rc = -EINVAL; |
| 215 | |
| 216 | file = filp_open(path, O_RDONLY, 0); |
| 217 | if (IS_ERR(file)) { |
| 218 | rc = PTR_ERR(file); |
| 219 | pr_err("Unable to open file: %s (%d)", path, rc); |
| 220 | return rc; |
| 221 | } |
| 222 | |
| 223 | size = i_size_read(file_inode(file)); |
| 224 | if (size <= 0) |
| 225 | goto out; |
| 226 | |
| 227 | buf = kmalloc(size, GFP_KERNEL); |
| 228 | if (!buf) { |
| 229 | rc = -ENOMEM; |
| 230 | goto out; |
| 231 | } |
| 232 | |
| 233 | rc = integrity_kernel_read(file, 0, buf, size); |
| 234 | if (rc < 0) |
| 235 | kfree(buf); |
| 236 | else if (rc != size) |
| 237 | rc = -EIO; |
| 238 | else |
| 239 | *data = buf; |
| 240 | out: |
| 241 | fput(file); |
| 242 | return rc; |
| 243 | } |
Dmitry Kasatkin | c9cd2ce | 2014-11-05 17:01:15 +0200 | [diff] [blame] | 244 | |
| 245 | /* |
| 246 | * integrity_load_keys - load integrity keys hook |
| 247 | * |
| 248 | * Hooks is called from init/main.c:kernel_init_freeable() |
| 249 | * when rootfs is ready |
| 250 | */ |
| 251 | void __init integrity_load_keys(void) |
| 252 | { |
| 253 | ima_load_x509(); |
| 254 | } |