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

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