linux-imx

/* Provide a way to create a superblock configuration context within the kernel

 * that allows a superblock to be set up prior to mounting.

 *

 * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.

 * Written by David Howells (dhowells@redhat.com)

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public Licence

 * as published by the Free Software Foundation; either version

 * 2 of the Licence, or (at your option) any later version.

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs_context.h>

#include <linux/fs_parser.h>

#include <linux/fs.h>

#include <linux/mount.h>

#include <linux/nsproxy.h>

#include <linux/slab.h>

#include <linux/magic.h>

#include <linux/security.h>

#include <linux/mnt_namespace.h>

#include <linux/pid_namespace.h>

#include <linux/user_namespace.h>

#include <net/net_namespace.h>

#include "mount.h"

#include "internal.h"

​

enum legacy_fs_param {

    LEGACY_FS_UNSET_PARAMS,

    LEGACY_FS_MONOLITHIC_PARAMS,

    LEGACY_FS_INDIVIDUAL_PARAMS,

};

​

struct legacy_fs_context {

    char            *legacy_data;   /* Data page for legacy filesystems */

    size_t          data_size;

    enum legacy_fs_param    param_type;

};

​

static int legacy_init_fs_context(struct fs_context *fc);

​

static const struct constant_table common_set_sb_flag[] = {

    { "dirsync",    SB_DIRSYNC },

    { "lazytime",   SB_LAZYTIME },

    { "mand",   SB_MANDLOCK },

    { "posixacl",   SB_POSIXACL },

    { "ro",     SB_RDONLY },

    { "sync",   SB_SYNCHRONOUS },

};

​

static const struct constant_table common_clear_sb_flag[] = {

    { "async",  SB_SYNCHRONOUS },

    { "nolazytime", SB_LAZYTIME },

    { "nomand", SB_MANDLOCK },

    { "rw",     SB_RDONLY },

    { "silent", SB_SILENT },

};

​

static const char *const forbidden_sb_flag[] = {

    "bind",

    "dev",

    "exec",

    "move",

    "noatime",

    "nodev",

    "nodiratime",

    "noexec",

    "norelatime",

    "nostrictatime",

    "nosuid",

    "private",

    "rec",

    "relatime",

    "remount",

    "shared",

    "slave",

    "strictatime",

    "suid",

    "unbindable",

};

​

/*

 * Check for a common mount option that manipulates s_flags.

 */

static int vfs_parse_sb_flag(struct fs_context *fc, const char *key)

{

    unsigned int token;

    unsigned int i;

​

    for (i = 0; i < ARRAY_SIZE(forbidden_sb_flag); i++)

        if (strcmp(key, forbidden_sb_flag[i]) == 0)