fs/ext2/xattr_trusted.c

   1 /*
   2  * linux/fs/ext2/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/fs.h>
  11 #include <linux/smp_lock.h>
  12 #include <linux/ext2_fs.h>
  13 #include "xattr.h"
  14
  15 #define XATTR_TRUSTED_PREFIX "trusted."
  16
  17 static size_t
  18 ext2_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
  19                         const char *name, size_t name_len)
  20 {
  21         const int prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;
  22         const size_t total_len = prefix_len + name_len + 1;
  23
  24         if (!capable(CAP_SYS_ADMIN))
  25                 return 0;
  26
  27         if (list && total_len <= list_size) {
  28                 memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
  29                 memcpy(list+prefix_len, name, name_len);
  30                 list[prefix_len + name_len] = '\0';
  31         }
  32         return total_len;
  33 }
  34
  35 static int
  36 ext2_xattr_trusted_get(struct inode *inode, const char *name,
  37                        void *buffer, size_t size)
  38 {
  39         if (strcmp(name, "") == 0)
  40                 return -EINVAL;
  41         if (!capable(CAP_SYS_ADMIN))
  42                 return -EPERM;
  43         return ext2_xattr_get(inode, EXT2_XATTR_INDEX_TRUSTED, name,
  44                               buffer, size);
  45 }
  46
  47 static int
  48 ext2_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         if (!capable(CAP_SYS_ADMIN))
  54                 return -EPERM;
  55         return ext2_xattr_set(inode, EXT2_XATTR_INDEX_TRUSTED, name,
  56                               value, size, flags);
  57 }
  58
  59 struct xattr_handler ext2_xattr_trusted_handler = {
  60         .prefix = XATTR_TRUSTED_PREFIX,
  61         .list   = ext2_xattr_trusted_list,
  62         .get    = ext2_xattr_trusted_get,
  63         .set    = ext2_xattr_trusted_set,
  64 };