LXR linux/fs/ext4/xattr

   1/*
   2 * linux/fs/ext4/xattr_security.c
   3 * Handler for storing security labels as extended attributes.
   4 */
   5
   6#include <linux/module.h>
   7#include <linux/string.h>
   8#include <linux/fs.h>
   9#include <linux/ext4_jbd2.h>
  10#include <linux/ext4_fs.h>
  11#include <linux/security.h>
  12#include "xattr.h"
  13
  14static size_t
  15ext4_xattr_security_list(struct inode *inode, char *list, size_t list_size,
  16                         const char *name, size_t name_len)
  17{
  18        const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
  19        const size_t total_len = prefix_len + name_len + 1;
  20
  21
  22        if (list && total_len <= list_size) {
  23                memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  24                memcpy(list+prefix_len, name, name_len);
  25                list[prefix_len + name_len] = '\0';
  26        }
  27        return total_len;
  28}
  29
  30static int
  31ext4_xattr_security_get(struct inode *inode, const char *name,
  32                       void *buffer, size_t size)
  33{
  34        if (strcmp(name, "") == 0)
  35                return -EINVAL;
  36        return ext4_xattr_get(inode, EXT4_XATTR_INDEX_SECURITY, name,
  37                              buffer, size);
  38}
  39
  40static int
  41ext4_xattr_security_set(struct inode *inode, const char *name,
  42                       const void *value, size_t size, int flags)
  43{
  44        if (strcmp(name, "") == 0)
  45                return -EINVAL;
  46        return ext4_xattr_set(inode, EXT4_XATTR_INDEX_SECURITY, name,
  47                              value, size, flags);
  48}
  49
  50int
  51ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir)
  52{
  53        int err;
  54        size_t len;
  55        void *value;
  56        char *name;
  57
  58        err = security_inode_init_security(inode, dir, &name, &value, &len);
  59        if (err) {
  60                if (err == -EOPNOTSUPP)
  61                        return 0;
  62                return err;
  63        }
  64        err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY,
  65                                    name, value, len, 0);
  66        kfree(name);
  67        kfree(value);
  68        return err;
  69}
  70
  71struct xattr_handler ext4_xattr_security_handler = {
  72        .prefix = XATTR_SECURITY_PREFIX,
  73        .list   = ext4_xattr_security_list,
  74        .get    = ext4_xattr_security_get,
  75        .set    = ext4_xattr_security_set,
  76};
  77