1/*
2 * linux/fs/ext4/xattr_security.c
3 * Handler for storing security labels as extended attributes.
4 */
5
6#include <linux/string.h>
7#include <linux/fs.h>
8#include <linux/security.h>
9#include <linux/slab.h>
10#include "ext4_jbd2.h"
11#include "ext4.h"
12#include "xattr.h"
13
14static size_t
15ext4_xattr_security_list(const struct xattr_handler *handler,
16			 struct dentry *dentry, char *list, size_t list_size,
17			 const char *name, size_t name_len)
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(const struct xattr_handler *handler,
33			struct dentry *dentry, const char *name,
34			void *buffer, size_t size)
35{
36	if (strcmp(name, "") == 0)
37		return -EINVAL;
38	return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
39			      name, buffer, size);
40}
41
42static int
43ext4_xattr_security_set(const struct xattr_handler *handler,
44			struct dentry *dentry, const char *name,
45			const void *value, size_t size, int flags)
46{
47	if (strcmp(name, "") == 0)
48		return -EINVAL;
49	return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
50			      name, value, size, flags);
51}
52
53static int
54ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
55		void *fs_info)
56{
57	const struct xattr *xattr;
58	handle_t *handle = fs_info;
59	int err = 0;
60
61	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
62		err = ext4_xattr_set_handle(handle, inode,
63					    EXT4_XATTR_INDEX_SECURITY,
64					    xattr->name, xattr->value,
65					    xattr->value_len, 0);
66		if (err < 0)
67			break;
68	}
69	return err;
70}
71
72int
73ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
74		   const struct qstr *qstr)
75{
76	return security_inode_init_security(inode, dir, qstr,
77					    &ext4_initxattrs, handle);
78}
79
80const struct xattr_handler ext4_xattr_security_handler = {
81	.prefix	= XATTR_SECURITY_PREFIX,
82	.list	= ext4_xattr_security_list,
83	.get	= ext4_xattr_security_get,
84	.set	= ext4_xattr_security_set,
85};
86