Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 1 | /* |
| 2 | * inode.c - securityfs |
| 3 | * |
| 4 | * Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License version |
| 8 | * 2 as published by the Free Software Foundation. |
| 9 | * |
| 10 | * Based on fs/debugfs/inode.c which had the following copyright notice: |
| 11 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> |
| 12 | * Copyright (C) 2004 IBM Inc. |
| 13 | */ |
| 14 | |
| 15 | /* #define DEBUG */ |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 16 | #include <linux/module.h> |
| 17 | #include <linux/fs.h> |
| 18 | #include <linux/mount.h> |
| 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/namei.h> |
| 22 | #include <linux/security.h> |
Mimi Zohar | 9256292 | 2008-10-07 14:00:12 -0400 | [diff] [blame] | 23 | #include <linux/magic.h> |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 24 | |
| 25 | static struct vfsmount *mount; |
| 26 | static int mount_count; |
| 27 | |
| 28 | /* |
| 29 | * TODO: |
| 30 | * I think I can get rid of these default_file_ops, but not quite sure... |
| 31 | */ |
| 32 | static ssize_t default_read_file(struct file *file, char __user *buf, |
| 33 | size_t count, loff_t *ppos) |
| 34 | { |
| 35 | return 0; |
| 36 | } |
| 37 | |
| 38 | static ssize_t default_write_file(struct file *file, const char __user *buf, |
| 39 | size_t count, loff_t *ppos) |
| 40 | { |
| 41 | return count; |
| 42 | } |
| 43 | |
| 44 | static int default_open(struct inode *inode, struct file *file) |
| 45 | { |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 46 | if (inode->i_private) |
| 47 | file->private_data = inode->i_private; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 48 | |
| 49 | return 0; |
| 50 | } |
| 51 | |
Arjan van de Ven | 9c2e08c | 2007-02-12 00:55:37 -0800 | [diff] [blame] | 52 | static const struct file_operations default_file_ops = { |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 53 | .read = default_read_file, |
| 54 | .write = default_write_file, |
| 55 | .open = default_open, |
| 56 | }; |
| 57 | |
| 58 | static struct inode *get_inode(struct super_block *sb, int mode, dev_t dev) |
| 59 | { |
| 60 | struct inode *inode = new_inode(sb); |
| 61 | |
| 62 | if (inode) { |
| 63 | inode->i_mode = mode; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 64 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 65 | switch (mode & S_IFMT) { |
| 66 | default: |
| 67 | init_special_inode(inode, mode, dev); |
| 68 | break; |
| 69 | case S_IFREG: |
| 70 | inode->i_fop = &default_file_ops; |
| 71 | break; |
| 72 | case S_IFDIR: |
| 73 | inode->i_op = &simple_dir_inode_operations; |
| 74 | inode->i_fop = &simple_dir_operations; |
| 75 | |
| 76 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 77 | inc_nlink(inode); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 78 | break; |
| 79 | } |
| 80 | } |
| 81 | return inode; |
| 82 | } |
| 83 | |
| 84 | /* SMP-safe */ |
| 85 | static int mknod(struct inode *dir, struct dentry *dentry, |
| 86 | int mode, dev_t dev) |
| 87 | { |
| 88 | struct inode *inode; |
Tvrtko Ursulin | b8bc83a | 2010-07-15 13:25:06 +0100 | [diff] [blame^] | 89 | int error = -ENOMEM; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 90 | |
| 91 | if (dentry->d_inode) |
| 92 | return -EEXIST; |
| 93 | |
| 94 | inode = get_inode(dir->i_sb, mode, dev); |
| 95 | if (inode) { |
| 96 | d_instantiate(dentry, inode); |
| 97 | dget(dentry); |
| 98 | error = 0; |
| 99 | } |
| 100 | return error; |
| 101 | } |
| 102 | |
| 103 | static int mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| 104 | { |
| 105 | int res; |
| 106 | |
| 107 | mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; |
| 108 | res = mknod(dir, dentry, mode, 0); |
| 109 | if (!res) |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 110 | inc_nlink(dir); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 111 | return res; |
| 112 | } |
| 113 | |
| 114 | static int create(struct inode *dir, struct dentry *dentry, int mode) |
| 115 | { |
| 116 | mode = (mode & S_IALLUGO) | S_IFREG; |
| 117 | return mknod(dir, dentry, mode, 0); |
| 118 | } |
| 119 | |
| 120 | static inline int positive(struct dentry *dentry) |
| 121 | { |
| 122 | return dentry->d_inode && !d_unhashed(dentry); |
| 123 | } |
| 124 | |
| 125 | static int fill_super(struct super_block *sb, void *data, int silent) |
| 126 | { |
| 127 | static struct tree_descr files[] = {{""}}; |
| 128 | |
| 129 | return simple_fill_super(sb, SECURITYFS_MAGIC, files); |
| 130 | } |
| 131 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 132 | static int get_sb(struct file_system_type *fs_type, |
| 133 | int flags, const char *dev_name, |
| 134 | void *data, struct vfsmount *mnt) |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 135 | { |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 136 | return get_sb_single(fs_type, flags, data, fill_super, mnt); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 137 | } |
| 138 | |
| 139 | static struct file_system_type fs_type = { |
| 140 | .owner = THIS_MODULE, |
| 141 | .name = "securityfs", |
| 142 | .get_sb = get_sb, |
| 143 | .kill_sb = kill_litter_super, |
| 144 | }; |
| 145 | |
| 146 | static int create_by_name(const char *name, mode_t mode, |
| 147 | struct dentry *parent, |
| 148 | struct dentry **dentry) |
| 149 | { |
| 150 | int error = 0; |
| 151 | |
| 152 | *dentry = NULL; |
| 153 | |
| 154 | /* If the parent is not specified, we create it in the root. |
| 155 | * We need the root dentry to do this, which is in the super |
| 156 | * block. A pointer to that is in the struct vfsmount that we |
| 157 | * have around. |
| 158 | */ |
Al Viro | ef52c75 | 2010-01-25 04:50:43 -0500 | [diff] [blame] | 159 | if (!parent) |
| 160 | parent = mount->mnt_sb->s_root; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 161 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 162 | mutex_lock(&parent->d_inode->i_mutex); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 163 | *dentry = lookup_one_len(name, parent, strlen(name)); |
Dan Carpenter | b338cc8 | 2010-04-22 12:05:35 +0200 | [diff] [blame] | 164 | if (!IS_ERR(*dentry)) { |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 165 | if ((mode & S_IFMT) == S_IFDIR) |
| 166 | error = mkdir(parent->d_inode, *dentry, mode); |
| 167 | else |
| 168 | error = create(parent->d_inode, *dentry, mode); |
Tvrtko Ursulin | b8bc83a | 2010-07-15 13:25:06 +0100 | [diff] [blame^] | 169 | if (error) |
| 170 | dput(*dentry); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 171 | } else |
Dan Carpenter | b338cc8 | 2010-04-22 12:05:35 +0200 | [diff] [blame] | 172 | error = PTR_ERR(*dentry); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 173 | mutex_unlock(&parent->d_inode->i_mutex); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 174 | |
| 175 | return error; |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * securityfs_create_file - create a file in the securityfs filesystem |
| 180 | * |
| 181 | * @name: a pointer to a string containing the name of the file to create. |
| 182 | * @mode: the permission that the file should have |
| 183 | * @parent: a pointer to the parent dentry for this file. This should be a |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 184 | * directory dentry if set. If this parameter is %NULL, then the |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 185 | * file will be created in the root of the securityfs filesystem. |
| 186 | * @data: a pointer to something that the caller will want to get to later |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 187 | * on. The inode.i_private pointer will point to this value on |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 188 | * the open() call. |
| 189 | * @fops: a pointer to a struct file_operations that should be used for |
| 190 | * this file. |
| 191 | * |
| 192 | * This is the basic "create a file" function for securityfs. It allows for a |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 193 | * wide range of flexibility in creating a file, or a directory (if you |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 194 | * want to create a directory, the securityfs_create_dir() function is |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 195 | * recommended to be used instead). |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 196 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 197 | * This function returns a pointer to a dentry if it succeeds. This |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 198 | * pointer must be passed to the securityfs_remove() function when the file is |
| 199 | * to be removed (no automatic cleanup happens if your module is unloaded, |
Serge E. Hallyn | faa3aad | 2009-02-02 15:07:33 -0800 | [diff] [blame] | 200 | * you are responsible here). If an error occurs, the function will return |
| 201 | * the erorr value (via ERR_PTR). |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 202 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 203 | * If securityfs is not enabled in the kernel, the value %-ENODEV is |
Serge E. Hallyn | faa3aad | 2009-02-02 15:07:33 -0800 | [diff] [blame] | 204 | * returned. |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 205 | */ |
| 206 | struct dentry *securityfs_create_file(const char *name, mode_t mode, |
| 207 | struct dentry *parent, void *data, |
Arjan van de Ven | 9c2e08c | 2007-02-12 00:55:37 -0800 | [diff] [blame] | 208 | const struct file_operations *fops) |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 209 | { |
| 210 | struct dentry *dentry = NULL; |
| 211 | int error; |
| 212 | |
| 213 | pr_debug("securityfs: creating file '%s'\n",name); |
| 214 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 215 | error = simple_pin_fs(&fs_type, &mount, &mount_count); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 216 | if (error) { |
| 217 | dentry = ERR_PTR(error); |
| 218 | goto exit; |
| 219 | } |
| 220 | |
| 221 | error = create_by_name(name, mode, parent, &dentry); |
| 222 | if (error) { |
| 223 | dentry = ERR_PTR(error); |
| 224 | simple_release_fs(&mount, &mount_count); |
| 225 | goto exit; |
| 226 | } |
| 227 | |
| 228 | if (dentry->d_inode) { |
| 229 | if (fops) |
| 230 | dentry->d_inode->i_fop = fops; |
| 231 | if (data) |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 232 | dentry->d_inode->i_private = data; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 233 | } |
| 234 | exit: |
| 235 | return dentry; |
| 236 | } |
| 237 | EXPORT_SYMBOL_GPL(securityfs_create_file); |
| 238 | |
| 239 | /** |
| 240 | * securityfs_create_dir - create a directory in the securityfs filesystem |
| 241 | * |
| 242 | * @name: a pointer to a string containing the name of the directory to |
| 243 | * create. |
| 244 | * @parent: a pointer to the parent dentry for this file. This should be a |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 245 | * directory dentry if set. If this parameter is %NULL, then the |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 246 | * directory will be created in the root of the securityfs filesystem. |
| 247 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 248 | * This function creates a directory in securityfs with the given @name. |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 249 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 250 | * This function returns a pointer to a dentry if it succeeds. This |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 251 | * pointer must be passed to the securityfs_remove() function when the file is |
| 252 | * to be removed (no automatic cleanup happens if your module is unloaded, |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 253 | * you are responsible here). If an error occurs, %NULL will be returned. |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 254 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 255 | * If securityfs is not enabled in the kernel, the value %-ENODEV is |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 256 | * returned. It is not wise to check for this value, but rather, check for |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 257 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 258 | * code. |
| 259 | */ |
| 260 | struct dentry *securityfs_create_dir(const char *name, struct dentry *parent) |
| 261 | { |
| 262 | return securityfs_create_file(name, |
| 263 | S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, |
| 264 | parent, NULL, NULL); |
| 265 | } |
| 266 | EXPORT_SYMBOL_GPL(securityfs_create_dir); |
| 267 | |
| 268 | /** |
| 269 | * securityfs_remove - removes a file or directory from the securityfs filesystem |
| 270 | * |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 271 | * @dentry: a pointer to a the dentry of the file or directory to be removed. |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 272 | * |
| 273 | * This function removes a file or directory in securityfs that was previously |
| 274 | * created with a call to another securityfs function (like |
| 275 | * securityfs_create_file() or variants thereof.) |
| 276 | * |
| 277 | * This function is required to be called in order for the file to be |
Randy Dunlap | 3f23d81 | 2008-08-17 21:44:22 -0700 | [diff] [blame] | 278 | * removed. No automatic cleanup of files will happen when a module is |
| 279 | * removed; you are responsible here. |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 280 | */ |
| 281 | void securityfs_remove(struct dentry *dentry) |
| 282 | { |
| 283 | struct dentry *parent; |
| 284 | |
Eric Paris | d93e4c9 | 2009-05-11 20:47:15 -0400 | [diff] [blame] | 285 | if (!dentry || IS_ERR(dentry)) |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 286 | return; |
| 287 | |
| 288 | parent = dentry->d_parent; |
| 289 | if (!parent || !parent->d_inode) |
| 290 | return; |
| 291 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 292 | mutex_lock(&parent->d_inode->i_mutex); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 293 | if (positive(dentry)) { |
| 294 | if (dentry->d_inode) { |
| 295 | if (S_ISDIR(dentry->d_inode->i_mode)) |
| 296 | simple_rmdir(parent->d_inode, dentry); |
| 297 | else |
| 298 | simple_unlink(parent->d_inode, dentry); |
| 299 | dput(dentry); |
| 300 | } |
| 301 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 302 | mutex_unlock(&parent->d_inode->i_mutex); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 303 | simple_release_fs(&mount, &mount_count); |
| 304 | } |
| 305 | EXPORT_SYMBOL_GPL(securityfs_remove); |
| 306 | |
Greg Kroah-Hartman | 69d8e13 | 2007-10-29 20:13:17 +0100 | [diff] [blame] | 307 | static struct kobject *security_kobj; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 308 | |
| 309 | static int __init securityfs_init(void) |
| 310 | { |
| 311 | int retval; |
| 312 | |
Greg Kroah-Hartman | 0ff21e4 | 2007-11-06 10:36:58 -0800 | [diff] [blame] | 313 | security_kobj = kobject_create_and_add("security", kernel_kobj); |
Greg Kroah-Hartman | 69d8e13 | 2007-10-29 20:13:17 +0100 | [diff] [blame] | 314 | if (!security_kobj) |
| 315 | return -EINVAL; |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 316 | |
| 317 | retval = register_filesystem(&fs_type); |
| 318 | if (retval) |
Greg Kroah-Hartman | 78a2d90 | 2007-12-20 08:13:05 -0800 | [diff] [blame] | 319 | kobject_put(security_kobj); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 320 | return retval; |
| 321 | } |
| 322 | |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 323 | core_initcall(securityfs_init); |
Greg KH | b67dbf9 | 2005-07-07 14:37:53 -0700 | [diff] [blame] | 324 | MODULE_LICENSE("GPL"); |
| 325 | |