/fs/ext4/xattr_security.c

 1/*
 2 * linux/fs/ext4/xattr_security.c
 3 * Handler for storing security labels as extended attributes.
 4 */
 5
 6#include <linux/module.h>
 7#include <linux/string.h>
 8#include <linux/fs.h>
 9#include <linux/security.h>
10#include <linux/slab.h>
11#include "ext4_jbd2.h"
12#include "ext4.h"
13#include "xattr.h"
14
15static size_t
16ext4_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
17		const char *name, size_t name_len, int type)
18{
19	const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
20	const size_t total_len = prefix_len + name_len + 1;
21
22
23	if (list && total_len <= list_size) {
24		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
25		memcpy(list+prefix_len, name, name_len);
26		list[prefix_len + name_len] = '\0';
27	}
28	return total_len;
29}
30
31static int
32ext4_xattr_security_get(struct dentry *dentry, const char *name,
33		       void *buffer, size_t size, int type)
34{
35	if (strcmp(name, "") == 0)
36		return -EINVAL;
37	return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
38			      name, buffer, size);
39}
40
41static int
42ext4_xattr_security_set(struct dentry *dentry, const char *name,
43		const void *value, size_t size, int flags, int type)
44{
45	if (strcmp(name, "") == 0)
46		return -EINVAL;
47	return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
48			      name, value, size, flags);
49}
50
51int
52ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
53		   const struct qstr *qstr)
54{
55	int err;
56	size_t len;
57	void *value;
58	char *name;
59
60	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
61	if (err) {
62		if (err == -EOPNOTSUPP)
63			return 0;
64		return err;
65	}
66	err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY,
67				    name, value, len, 0);
68	kfree(name);
69	kfree(value);
70	return err;
71}
72
73const struct xattr_handler ext4_xattr_security_handler = {
74	.prefix	= XATTR_SECURITY_PREFIX,
75	.list	= ext4_xattr_security_list,
76	.get	= ext4_xattr_security_get,
77	.set	= ext4_xattr_security_set,
78};