fs/ext4/xattr_trusted.c

   1 /*
   2  * linux/fs/ext4/xattr_trusted.c
   3  * Handler for trusted extended attributes.
   4  *
   5  * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/string.h>
  10 #include <linux/capability.h>
  11 #include <linux/fs.h>
  12 #include "ext4_jbd2.h"
  13 #include "ext4.h"
  14 #include "xattr.h"
  15
  16 static size_t
  17 ext4_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
  18                         const char *name, size_t name_len)
  19 {
  20         const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
  21         const size_t total_len = prefix_len + name_len + 1;
  22
  23         if (!capable(CAP_SYS_ADMIN))
  24                 return 0;
  25
  26         if (list && total_len <= list_size) {
  27                 memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
  28                 memcpy(list+prefix_len, name, name_len);
  29                 list[prefix_len + name_len] = '\0';
  30         }
  31         return total_len;
  32 }
  33
  34 static int
  35 ext4_xattr_trusted_get(struct inode *inode, const char *name,
  36                        void *buffer, size_t size)
  37 {
  38         if (strcmp(name, "") == 0)
  39                 return -EINVAL;
  40         return ext4_xattr_get(inode, EXT4_XATTR_INDEX_TRUSTED, name,
  41                               buffer, size);
  42 }
  43
  44 static int
  45 ext4_xattr_trusted_set(struct inode *inode, const char *name,
  46                        const void *value, size_t size, int flags)
  47 {
  48         if (strcmp(name, "") == 0)
  49                 return -EINVAL;
  50         return ext4_xattr_set(inode, EXT4_XATTR_INDEX_TRUSTED, name,
  51                               value, size, flags);
  52 }
  53
  54 struct xattr_handler ext4_xattr_trusted_handler = {
  55         .prefix = XATTR_TRUSTED_PREFIX,
  56         .list   = ext4_xattr_trusted_list,
  57         .get    = ext4_xattr_trusted_get,
  58         .set    = ext4_xattr_trusted_set,
  59 };