xattr_security.c revision 9d8f13ba3f4833219e50767b022b82cd0da930eb 
1#include <linux/reiserfs_fs.h>
2#include <linux/errno.h>
3#include <linux/fs.h>
4#include <linux/pagemap.h>
5#include <linux/xattr.h>
6#include <linux/slab.h>
7#include <linux/reiserfs_xattr.h>
8#include <linux/security.h>
9#include <asm/uaccess.h>
10
11static int
12security_get(struct dentry *dentry, const char *name, void *buffer, size_t size,
13		int handler_flags)
14{
15	if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
16		return -EINVAL;
17
18	if (IS_PRIVATE(dentry->d_inode))
19		return -EPERM;
20
21	return reiserfs_xattr_get(dentry->d_inode, name, buffer, size);
22}
23
24static int
25security_set(struct dentry *dentry, const char *name, const void *buffer,
26	     size_t size, int flags, int handler_flags)
27{
28	if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
29		return -EINVAL;
30
31	if (IS_PRIVATE(dentry->d_inode))
32		return -EPERM;
33
34	return reiserfs_xattr_set(dentry->d_inode, name, buffer, size, flags);
35}
36
37static size_t security_list(struct dentry *dentry, char *list, size_t list_len,
38			    const char *name, size_t namelen, int handler_flags)
39{
40	const size_t len = namelen + 1;
41
42	if (IS_PRIVATE(dentry->d_inode))
43		return 0;
44
45	if (list && len <= list_len) {
46		memcpy(list, name, namelen);
47		list[namelen] = '\0';
48	}
49
50	return len;
51}
52
53/* Initializes the security context for a new inode and returns the number
54 * of blocks needed for the transaction. If successful, reiserfs_security
55 * must be released using reiserfs_security_free when the caller is done. */
56int reiserfs_security_init(struct inode *dir, struct inode *inode,
57			   const struct qstr *qstr,
58			   struct reiserfs_security_handle *sec)
59{
60	int blocks = 0;
61	int error;
62
63	sec->name = NULL;
64
65	/* Don't add selinux attributes on xattrs - they'll never get used */
66	if (IS_PRIVATE(dir))
67		return 0;
68
69	error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
70						 &sec->value, &sec->length);
71	if (error) {
72		if (error == -EOPNOTSUPP)
73			error = 0;
74
75		sec->name = NULL;
76		sec->value = NULL;
77		sec->length = 0;
78		return error;
79	}
80
81	if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
82		blocks = reiserfs_xattr_jcreate_nblocks(inode) +
83			 reiserfs_xattr_nblocks(inode, sec->length);
84		/* We don't want to count the directories twice if we have
85		 * a default ACL. */
86		REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
87	}
88	return blocks;
89}
90
91int reiserfs_security_write(struct reiserfs_transaction_handle *th,
92			    struct inode *inode,
93			    struct reiserfs_security_handle *sec)
94{
95	int error;
96	if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
97		return -EINVAL;
98
99	error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
100					  sec->length, XATTR_CREATE);
101	if (error == -ENODATA || error == -EOPNOTSUPP)
102		error = 0;
103
104	return error;
105}
106
107void reiserfs_security_free(struct reiserfs_security_handle *sec)
108{
109	kfree(sec->name);
110	kfree(sec->value);
111	sec->name = NULL;
112	sec->value = NULL;
113}
114
115const struct xattr_handler reiserfs_xattr_security_handler = {
116	.prefix = XATTR_SECURITY_PREFIX,
117	.get = security_get,
118	.set = security_set,
119	.list = security_list,
120};
121