]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - security/inode.c
perf annotate browser: Display titles in left frame
[mirror_ubuntu-artful-kernel.git] / security / inode.c
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 */
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>
23 #include <linux/lsm_hooks.h>
24 #include <linux/magic.h>
25
26 static struct vfsmount *mount;
27 static int mount_count;
28
29 static int fill_super(struct super_block *sb, void *data, int silent)
30 {
31 static const struct tree_descr files[] = {{""}};
32
33 return simple_fill_super(sb, SECURITYFS_MAGIC, files);
34 }
35
36 static struct dentry *get_sb(struct file_system_type *fs_type,
37 int flags, const char *dev_name,
38 void *data)
39 {
40 return mount_single(fs_type, flags, data, fill_super);
41 }
42
43 static struct file_system_type fs_type = {
44 .owner = THIS_MODULE,
45 .name = "securityfs",
46 .mount = get_sb,
47 .kill_sb = kill_litter_super,
48 };
49
50 /**
51 * securityfs_create_file - create a file in the securityfs filesystem
52 *
53 * @name: a pointer to a string containing the name of the file to create.
54 * @mode: the permission that the file should have
55 * @parent: a pointer to the parent dentry for this file. This should be a
56 * directory dentry if set. If this parameter is %NULL, then the
57 * file will be created in the root of the securityfs filesystem.
58 * @data: a pointer to something that the caller will want to get to later
59 * on. The inode.i_private pointer will point to this value on
60 * the open() call.
61 * @fops: a pointer to a struct file_operations that should be used for
62 * this file.
63 *
64 * This is the basic "create a file" function for securityfs. It allows for a
65 * wide range of flexibility in creating a file, or a directory (if you
66 * want to create a directory, the securityfs_create_dir() function is
67 * recommended to be used instead).
68 *
69 * This function returns a pointer to a dentry if it succeeds. This
70 * pointer must be passed to the securityfs_remove() function when the file is
71 * to be removed (no automatic cleanup happens if your module is unloaded,
72 * you are responsible here). If an error occurs, the function will return
73 * the error value (via ERR_PTR).
74 *
75 * If securityfs is not enabled in the kernel, the value %-ENODEV is
76 * returned.
77 */
78 struct dentry *securityfs_create_file(const char *name, umode_t mode,
79 struct dentry *parent, void *data,
80 const struct file_operations *fops)
81 {
82 struct dentry *dentry;
83 int is_dir = S_ISDIR(mode);
84 struct inode *dir, *inode;
85 int error;
86
87 if (!is_dir) {
88 BUG_ON(!fops);
89 mode = (mode & S_IALLUGO) | S_IFREG;
90 }
91
92 pr_debug("securityfs: creating file '%s'\n",name);
93
94 error = simple_pin_fs(&fs_type, &mount, &mount_count);
95 if (error)
96 return ERR_PTR(error);
97
98 if (!parent)
99 parent = mount->mnt_root;
100
101 dir = d_inode(parent);
102
103 inode_lock(dir);
104 dentry = lookup_one_len(name, parent, strlen(name));
105 if (IS_ERR(dentry))
106 goto out;
107
108 if (d_really_is_positive(dentry)) {
109 error = -EEXIST;
110 goto out1;
111 }
112
113 inode = new_inode(dir->i_sb);
114 if (!inode) {
115 error = -ENOMEM;
116 goto out1;
117 }
118
119 inode->i_ino = get_next_ino();
120 inode->i_mode = mode;
121 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
122 inode->i_private = data;
123 if (is_dir) {
124 inode->i_op = &simple_dir_inode_operations;
125 inode->i_fop = &simple_dir_operations;
126 inc_nlink(inode);
127 inc_nlink(dir);
128 } else {
129 inode->i_fop = fops;
130 }
131 d_instantiate(dentry, inode);
132 dget(dentry);
133 inode_unlock(dir);
134 return dentry;
135
136 out1:
137 dput(dentry);
138 dentry = ERR_PTR(error);
139 out:
140 inode_unlock(dir);
141 simple_release_fs(&mount, &mount_count);
142 return dentry;
143 }
144 EXPORT_SYMBOL_GPL(securityfs_create_file);
145
146 /**
147 * securityfs_create_dir - create a directory in the securityfs filesystem
148 *
149 * @name: a pointer to a string containing the name of the directory to
150 * create.
151 * @parent: a pointer to the parent dentry for this file. This should be a
152 * directory dentry if set. If this parameter is %NULL, then the
153 * directory will be created in the root of the securityfs filesystem.
154 *
155 * This function creates a directory in securityfs with the given @name.
156 *
157 * This function returns a pointer to a dentry if it succeeds. This
158 * pointer must be passed to the securityfs_remove() function when the file is
159 * to be removed (no automatic cleanup happens if your module is unloaded,
160 * you are responsible here). If an error occurs, the function will return
161 * the error value (via ERR_PTR).
162 *
163 * If securityfs is not enabled in the kernel, the value %-ENODEV is
164 * returned.
165 */
166 struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
167 {
168 return securityfs_create_file(name,
169 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
170 parent, NULL, NULL);
171 }
172 EXPORT_SYMBOL_GPL(securityfs_create_dir);
173
174 /**
175 * securityfs_remove - removes a file or directory from the securityfs filesystem
176 *
177 * @dentry: a pointer to a the dentry of the file or directory to be removed.
178 *
179 * This function removes a file or directory in securityfs that was previously
180 * created with a call to another securityfs function (like
181 * securityfs_create_file() or variants thereof.)
182 *
183 * This function is required to be called in order for the file to be
184 * removed. No automatic cleanup of files will happen when a module is
185 * removed; you are responsible here.
186 */
187 void securityfs_remove(struct dentry *dentry)
188 {
189 struct inode *dir;
190
191 if (!dentry || IS_ERR(dentry))
192 return;
193
194 dir = d_inode(dentry->d_parent);
195 inode_lock(dir);
196 if (simple_positive(dentry)) {
197 if (d_is_dir(dentry))
198 simple_rmdir(dir, dentry);
199 else
200 simple_unlink(dir, dentry);
201 dput(dentry);
202 }
203 inode_unlock(dir);
204 simple_release_fs(&mount, &mount_count);
205 }
206 EXPORT_SYMBOL_GPL(securityfs_remove);
207
208 #ifdef CONFIG_SECURITY
209 static struct dentry *lsm_dentry;
210 static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count,
211 loff_t *ppos)
212 {
213 return simple_read_from_buffer(buf, count, ppos, lsm_names,
214 strlen(lsm_names));
215 }
216
217 static const struct file_operations lsm_ops = {
218 .read = lsm_read,
219 .llseek = generic_file_llseek,
220 };
221 #endif
222
223 static int __init securityfs_init(void)
224 {
225 int retval;
226
227 retval = sysfs_create_mount_point(kernel_kobj, "security");
228 if (retval)
229 return retval;
230
231 retval = register_filesystem(&fs_type);
232 if (retval) {
233 sysfs_remove_mount_point(kernel_kobj, "security");
234 return retval;
235 }
236 #ifdef CONFIG_SECURITY
237 lsm_dentry = securityfs_create_file("lsm", 0444, NULL, NULL,
238 &lsm_ops);
239 #endif
240 return 0;
241 }
242
243 core_initcall(securityfs_init);
244 MODULE_LICENSE("GPL");
245