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b67dbf9d GKH |
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 */ | |
b67dbf9d GKH |
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> | |
92562927 | 23 | #include <linux/magic.h> |
b67dbf9d GKH |
24 | |
25 | static struct vfsmount *mount; | |
26 | static int mount_count; | |
27 | ||
b67dbf9d GKH |
28 | static int fill_super(struct super_block *sb, void *data, int silent) |
29 | { | |
30 | static struct tree_descr files[] = {{""}}; | |
31 | ||
32 | return simple_fill_super(sb, SECURITYFS_MAGIC, files); | |
33 | } | |
34 | ||
fc14f2fe | 35 | static struct dentry *get_sb(struct file_system_type *fs_type, |
454e2398 | 36 | int flags, const char *dev_name, |
fc14f2fe | 37 | void *data) |
b67dbf9d | 38 | { |
fc14f2fe | 39 | return mount_single(fs_type, flags, data, fill_super); |
b67dbf9d GKH |
40 | } |
41 | ||
42 | static struct file_system_type fs_type = { | |
43 | .owner = THIS_MODULE, | |
44 | .name = "securityfs", | |
fc14f2fe | 45 | .mount = get_sb, |
b67dbf9d GKH |
46 | .kill_sb = kill_litter_super, |
47 | }; | |
48 | ||
4125e8e9 JJ |
49 | int securityfs_pin_fs(void) |
50 | { | |
51 | return simple_pin_fs(&fs_type, &mount, &mount_count); | |
52 | } | |
53 | ||
54 | int __securityfs_setup_d_inode(struct inode *dir, struct dentry *dentry, | |
55 | umode_t mode, void *data, | |
56 | const struct file_operations *fops, | |
57 | const struct inode_operations *iops) | |
58 | { | |
59 | bool is_dir = S_ISDIR(mode); | |
60 | struct inode *inode = new_inode(dir->i_sb); | |
61 | if (!inode) | |
62 | return -ENOMEM; | |
63 | ||
64 | inode->i_ino = get_next_ino(); | |
65 | inode->i_mode = mode; | |
66 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
67 | inode->i_private = data; | |
68 | if (is_dir) { | |
69 | inode->i_op = iops ? iops : &simple_dir_inode_operations; | |
70 | inode->i_fop = &simple_dir_operations; | |
71 | inc_nlink(inode); | |
72 | inc_nlink(dir); | |
73 | } else { | |
74 | inode->i_fop = fops; | |
75 | } | |
76 | d_instantiate(dentry, inode); | |
77 | dget(dentry); | |
78 | ||
79 | return 0; | |
80 | } | |
81 | EXPORT_SYMBOL_GPL(__securityfs_setup_d_inode); | |
82 | ||
b67dbf9d | 83 | /** |
4125e8e9 | 84 | * securityfs_create_dentry - create a file/dir in the securityfs filesystem |
b67dbf9d GKH |
85 | * |
86 | * @name: a pointer to a string containing the name of the file to create. | |
87 | * @mode: the permission that the file should have | |
88 | * @parent: a pointer to the parent dentry for this file. This should be a | |
3f23d815 | 89 | * directory dentry if set. If this parameter is %NULL, then the |
b67dbf9d GKH |
90 | * file will be created in the root of the securityfs filesystem. |
91 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 92 | * on. The inode.i_private pointer will point to this value on |
b67dbf9d GKH |
93 | * the open() call. |
94 | * @fops: a pointer to a struct file_operations that should be used for | |
95 | * this file. | |
4125e8e9 JJ |
96 | * @iops: a point to a struct of inode_operations that should be used for |
97 | * this file/dir | |
b67dbf9d | 98 | * |
4125e8e9 | 99 | * This is the basic "create a xxx" function for securityfs. It allows for a |
3f23d815 | 100 | * wide range of flexibility in creating a file, or a directory (if you |
b67dbf9d | 101 | * want to create a directory, the securityfs_create_dir() function is |
3f23d815 | 102 | * recommended to be used instead). |
b67dbf9d | 103 | * |
3f23d815 | 104 | * This function returns a pointer to a dentry if it succeeds. This |
b67dbf9d GKH |
105 | * pointer must be passed to the securityfs_remove() function when the file is |
106 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
faa3aad7 | 107 | * you are responsible here). If an error occurs, the function will return |
da3dae54 | 108 | * the error value (via ERR_PTR). |
b67dbf9d | 109 | * |
3f23d815 | 110 | * If securityfs is not enabled in the kernel, the value %-ENODEV is |
faa3aad7 | 111 | * returned. |
b67dbf9d | 112 | */ |
4125e8e9 JJ |
113 | struct dentry *securityfs_create_dentry(const char *name, umode_t mode, |
114 | struct dentry *parent, void *data, | |
115 | const struct file_operations *fops, | |
116 | const struct inode_operations *iops) | |
b67dbf9d | 117 | { |
3e25eb9c AV |
118 | struct dentry *dentry; |
119 | int is_dir = S_ISDIR(mode); | |
4125e8e9 | 120 | struct inode *dir; |
b67dbf9d GKH |
121 | int error; |
122 | ||
3e25eb9c AV |
123 | if (!is_dir) { |
124 | BUG_ON(!fops); | |
125 | mode = (mode & S_IALLUGO) | S_IFREG; | |
126 | } | |
127 | ||
b67dbf9d GKH |
128 | pr_debug("securityfs: creating file '%s'\n",name); |
129 | ||
1f5ce9e9 | 130 | error = simple_pin_fs(&fs_type, &mount, &mount_count); |
3e25eb9c AV |
131 | if (error) |
132 | return ERR_PTR(error); | |
133 | ||
134 | if (!parent) | |
135 | parent = mount->mnt_root; | |
136 | ||
ce0b16dd | 137 | dir = d_inode(parent); |
3e25eb9c AV |
138 | |
139 | mutex_lock(&dir->i_mutex); | |
140 | dentry = lookup_one_len(name, parent, strlen(name)); | |
141 | if (IS_ERR(dentry)) | |
142 | goto out; | |
143 | ||
ce0b16dd | 144 | if (d_really_is_positive(dentry)) { |
3e25eb9c AV |
145 | error = -EEXIST; |
146 | goto out1; | |
b67dbf9d GKH |
147 | } |
148 | ||
4125e8e9 JJ |
149 | error = __securityfs_setup_d_inode(dir, dentry, mode, data, fops, iops); |
150 | if (error) | |
3e25eb9c | 151 | goto out1; |
3e25eb9c AV |
152 | mutex_unlock(&dir->i_mutex); |
153 | return dentry; | |
154 | ||
155 | out1: | |
156 | dput(dentry); | |
157 | dentry = ERR_PTR(error); | |
158 | out: | |
159 | mutex_unlock(&dir->i_mutex); | |
160 | simple_release_fs(&mount, &mount_count); | |
b67dbf9d GKH |
161 | return dentry; |
162 | } | |
4125e8e9 JJ |
163 | EXPORT_SYMBOL_GPL(securityfs_create_dentry); |
164 | ||
165 | /** | |
166 | * securityfs_create_file - create a file in the securityfs filesystem | |
167 | * | |
168 | * @name: a pointer to a string containing the name of the file to create. | |
169 | * @mode: the permission that the file should have | |
170 | * @parent: a pointer to the parent dentry for this file. This should be a | |
171 | * directory dentry if set. If this parameter is %NULL, then the | |
172 | * file will be created in the root of the securityfs filesystem. | |
173 | * @data: a pointer to something that the caller will want to get to later | |
174 | * on. The inode.i_private pointer will point to this value on | |
175 | * the open() call. | |
176 | * @fops: a pointer to a struct file_operations that should be used for | |
177 | * this file. | |
178 | * | |
179 | * This function creates a file in securityfs with the given @name. | |
180 | * | |
181 | * This function returns a pointer to a dentry if it succeeds. This | |
182 | * pointer must be passed to the securityfs_remove() function when the file is | |
183 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
184 | * you are responsible here). If an error occurs, the function will return | |
185 | * the error value (via ERR_PTR). | |
186 | * | |
187 | * If securityfs is not enabled in the kernel, the value %-ENODEV is | |
188 | * returned. | |
189 | */ | |
190 | struct dentry *securityfs_create_file(const char *name, umode_t mode, | |
191 | struct dentry *parent, void *data, | |
192 | const struct file_operations *fops) | |
193 | { | |
194 | return securityfs_create_dentry(name, mode, parent, data, fops, NULL); | |
195 | } | |
b67dbf9d GKH |
196 | EXPORT_SYMBOL_GPL(securityfs_create_file); |
197 | ||
198 | /** | |
199 | * securityfs_create_dir - create a directory in the securityfs filesystem | |
200 | * | |
201 | * @name: a pointer to a string containing the name of the directory to | |
202 | * create. | |
203 | * @parent: a pointer to the parent dentry for this file. This should be a | |
3f23d815 | 204 | * directory dentry if set. If this parameter is %NULL, then the |
b67dbf9d GKH |
205 | * directory will be created in the root of the securityfs filesystem. |
206 | * | |
3f23d815 | 207 | * This function creates a directory in securityfs with the given @name. |
b67dbf9d | 208 | * |
3f23d815 | 209 | * This function returns a pointer to a dentry if it succeeds. This |
b67dbf9d GKH |
210 | * pointer must be passed to the securityfs_remove() function when the file is |
211 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
3f23d815 | 212 | * you are responsible here). If an error occurs, %NULL will be returned. |
b67dbf9d | 213 | * |
3f23d815 | 214 | * If securityfs is not enabled in the kernel, the value %-ENODEV is |
b67dbf9d | 215 | * returned. It is not wise to check for this value, but rather, check for |
3f23d815 | 216 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
b67dbf9d GKH |
217 | * code. |
218 | */ | |
219 | struct dentry *securityfs_create_dir(const char *name, struct dentry *parent) | |
220 | { | |
221 | return securityfs_create_file(name, | |
222 | S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, | |
223 | parent, NULL, NULL); | |
224 | } | |
225 | EXPORT_SYMBOL_GPL(securityfs_create_dir); | |
226 | ||
227 | /** | |
228 | * securityfs_remove - removes a file or directory from the securityfs filesystem | |
229 | * | |
3f23d815 | 230 | * @dentry: a pointer to a the dentry of the file or directory to be removed. |
b67dbf9d GKH |
231 | * |
232 | * This function removes a file or directory in securityfs that was previously | |
233 | * created with a call to another securityfs function (like | |
234 | * securityfs_create_file() or variants thereof.) | |
235 | * | |
236 | * This function is required to be called in order for the file to be | |
3f23d815 RD |
237 | * removed. No automatic cleanup of files will happen when a module is |
238 | * removed; you are responsible here. | |
b67dbf9d GKH |
239 | */ |
240 | void securityfs_remove(struct dentry *dentry) | |
241 | { | |
242 | struct dentry *parent; | |
243 | ||
d93e4c94 | 244 | if (!dentry || IS_ERR(dentry)) |
b67dbf9d GKH |
245 | return; |
246 | ||
247 | parent = dentry->d_parent; | |
ce0b16dd | 248 | if (!parent || d_really_is_negative(parent)) |
b67dbf9d GKH |
249 | return; |
250 | ||
ce0b16dd | 251 | mutex_lock(&d_inode(parent)->i_mutex); |
dc3f4198 AV |
252 | if (simple_positive(dentry)) { |
253 | if (d_is_dir(dentry)) | |
254 | simple_rmdir(d_inode(parent), dentry); | |
255 | else | |
256 | simple_unlink(d_inode(parent), dentry); | |
257 | dput(dentry); | |
b67dbf9d | 258 | } |
ce0b16dd | 259 | mutex_unlock(&d_inode(parent)->i_mutex); |
b67dbf9d GKH |
260 | simple_release_fs(&mount, &mount_count); |
261 | } | |
262 | EXPORT_SYMBOL_GPL(securityfs_remove); | |
263 | ||
b67dbf9d GKH |
264 | static int __init securityfs_init(void) |
265 | { | |
266 | int retval; | |
267 | ||
f9bb4882 EB |
268 | retval = sysfs_create_mount_point(kernel_kobj, "security"); |
269 | if (retval) | |
270 | return retval; | |
b67dbf9d GKH |
271 | |
272 | retval = register_filesystem(&fs_type); | |
273 | if (retval) | |
f9bb4882 | 274 | sysfs_remove_mount_point(kernel_kobj, "security"); |
b67dbf9d GKH |
275 | return retval; |
276 | } | |
277 | ||
b67dbf9d | 278 | core_initcall(securityfs_init); |
b67dbf9d GKH |
279 | MODULE_LICENSE("GPL"); |
280 |