kernel/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/string.h>
   9 #include <linux/capability.h>
  10 #include <linux/fs.h>
  11 #include "ext4_jbd2.h"
  12 #include "ext4.h"
  13 #include "xattr.h"
  14
  15 static size_t
  16 ext4_xattr_trusted_list(struct dentry *dentry, char *list, size_t list_size,
  17                 const char *name, size_t name_len, int type)
  18 {
  19         const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
  20         const size_t total_len = prefix_len + name_len + 1;
  21
  22         if (!capable(CAP_SYS_ADMIN))
  23                 return 0;
  24
  25         if (list && total_len <= list_size) {
  26                 memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
  27                 memcpy(list+prefix_len, name, name_len);
  28                 list[prefix_len + name_len] = '\0';
  29         }
  30         return total_len;
  31 }
  32
  33 static int
  34 ext4_xattr_trusted_get(struct dentry *dentry, const char *name, void *buffer,
  35                 size_t size, int type)
  36 {
  37         if (strcmp(name, "") == 0)
  38                 return -EINVAL;
  39         return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_TRUSTED,
  40                               name, buffer, size);
  41 }
  42
  43 static int
  44 ext4_xattr_trusted_set(struct dentry *dentry, const char *name,
  45                 const void *value, size_t size, int flags, int type)
  46 {
  47         if (strcmp(name, "") == 0)
  48                 return -EINVAL;
  49         return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_TRUSTED,
  50                               name, value, size, flags);
  51 }
  52
  53 const struct xattr_handler ext4_xattr_trusted_handler = {
  54         .prefix = XATTR_TRUSTED_PREFIX,
  55         .list   = ext4_xattr_trusted_list,
  56         .get    = ext4_xattr_trusted_get,
  57         .set    = ext4_xattr_trusted_set,
  58 };