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