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 <linux/smp_lock.h>
  13 #include <linux/ext4_jbd2.h>
  14 #include <linux/ext4_fs.h>
  15 #include "xattr.h"
  16
  17 #define XATTR_TRUSTED_PREFIX "trusted."
  18
  19 static size_t
  20 ext4_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
  21                         const char *name, size_t name_len)
  22 {
  23         const size_t prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;
  24         const size_t total_len = prefix_len + name_len + 1;
  25
  26         if (!capable(CAP_SYS_ADMIN))
  27                 return 0;
  28
  29         if (list && total_len <= list_size) {
  30                 memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
  31                 memcpy(list+prefix_len, name, name_len);
  32                 list[prefix_len + name_len] = '\0';
  33         }
  34         return total_len;
  35 }
  36
  37 static int
  38 ext4_xattr_trusted_get(struct inode *inode, const char *name,
  39                        void *buffer, size_t size)
  40 {
  41         if (strcmp(name, "") == 0)
  42                 return -EINVAL;
  43         return ext4_xattr_get(inode, EXT4_XATTR_INDEX_TRUSTED, name,
  44                               buffer, size);
  45 }
  46
  47 static int
  48 ext4_xattr_trusted_set(struct inode *inode, const char *name,
  49                        const void *value, size_t size, int flags)
  50 {
  51         if (strcmp(name, "") == 0)
  52                 return -EINVAL;
  53         return ext4_xattr_set(inode, EXT4_XATTR_INDEX_TRUSTED, name,
  54                               value, size, flags);
  55 }
  56
  57 struct xattr_handler ext4_xattr_trusted_handler = {
  58         .prefix = XATTR_TRUSTED_PREFIX,
  59         .list   = ext4_xattr_trusted_list,
  60         .get    = ext4_xattr_trusted_get,
  61         .set    = ext4_xattr_trusted_set,
  62 };