vfs: Distinguish between full xattr names and proper prefixes
[cascardo/linux.git] / 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/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
14 static size_t
15 ext4_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
31 static int
32 ext4_xattr_security_get(const struct xattr_handler *handler,
33                         struct dentry *dentry, const char *name,
34                         void *buffer, size_t size)
35 {
36         return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
37                               name, buffer, size);
38 }
39
40 static int
41 ext4_xattr_security_set(const struct xattr_handler *handler,
42                         struct dentry *dentry, const char *name,
43                         const void *value, size_t size, int flags)
44 {
45         return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
46                               name, value, size, flags);
47 }
48
49 static int
50 ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
51                 void *fs_info)
52 {
53         const struct xattr *xattr;
54         handle_t *handle = fs_info;
55         int err = 0;
56
57         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
58                 err = ext4_xattr_set_handle(handle, inode,
59                                             EXT4_XATTR_INDEX_SECURITY,
60                                             xattr->name, xattr->value,
61                                             xattr->value_len, 0);
62                 if (err < 0)
63                         break;
64         }
65         return err;
66 }
67
68 int
69 ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
70                    const struct qstr *qstr)
71 {
72         return security_inode_init_security(inode, dir, qstr,
73                                             &ext4_initxattrs, handle);
74 }
75
76 const struct xattr_handler ext4_xattr_security_handler = {
77         .prefix = XATTR_SECURITY_PREFIX,
78         .list   = ext4_xattr_security_list,
79         .get    = ext4_xattr_security_get,
80         .set    = ext4_xattr_security_set,
81 };