path: root/fs/ntfs3/super.c

// SPDX-License-Identifier: GPL-2.0
/*
 *
 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
 *
 *
 *                 terminology
 *
 * cluster - allocation unit     - 512,1K,2K,4K,...,2M
 * vcn - virtual cluster number  - Offset inside the file in clusters.
 * vbo - virtual byte offset     - Offset inside the file in bytes.
 * lcn - logical cluster number  - 0 based cluster in clusters heap.
 * lbo - logical byte offset     - Absolute position inside volume.
 * run - maps VCN to LCN         - Stored in attributes in packed form.
 * attr - attribute segment      - std/name/data etc records inside MFT.
 * mi  - MFT inode               - One MFT record(usually 1024 bytes or 4K), consists of attributes.
 * ni  - NTFS inode              - Extends linux inode. consists of one or more mft inodes.
 * index - unit inside directory - 2K, 4K, <=page size, does not depend on cluster size.
 *
 * WSL - Windows Subsystem for Linux
 * https://docs.microsoft.com/en-us/windows/wsl/file-permissions
 * It stores uid/gid/mode/dev in xattr
 *
 */

#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/exportfs.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/log2.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/nls.h>
#include <linux/seq_file.h>
#include <linux/statfs.h>

#include "debug.h"
#include "ntfs.h"
#include "ntfs_fs.h"
#ifdef CONFIG_NTFS3_LZX_XPRESS
#include "lib/lib.h"
#endif

#ifdef CONFIG_PRINTK
/*
 * ntfs_printk - Trace warnings/notices/errors.
 *
 * Thanks Joe Perches <joe@perches.com> for implementation
 */
void ntfs_printk(const struct super_block *sb, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	int level;
	struct ntfs_sb_info *sbi = sb->s_fs_info;

	/* Should we use different ratelimits for warnings/notices/errors? */
	if (!___ratelimit(&sbi->msg_ratelimit, "ntfs3"))
		return;

	va_start(args, fmt);

	level = printk_get_level(fmt);
	vaf.fmt = printk_skip_level(fmt);
	vaf.va = &args;
	printk("%c%cntfs3: %s: %pV\n", KERN_SOH_ASCII, level, sb->s_id, &vaf);

	va_end(args);
}

static char s_name_buf[512];
static atomic_t s_name_buf_cnt = ATOMIC_INIT(1); // 1 means 'free s_name_buf'.

/*
 * ntfs_inode_printk
 *
 * Print warnings/notices/errors about inode using name or inode number.
 */
void ntfs_inode_printk(struct inode *inode, const char *fmt, ...)
{
	struct super_block *sb = inode->i_sb;
	struct ntfs_sb_info *sbi = sb->s_fs_info;
	char *name;
	va_list args;
	struct va_format vaf;
	int level;

	if (!___ratelimit(&sbi->msg_ratelimit, "ntfs3"))
		return;

	/* Use static allocated buffer, if possible. */
	name = atomic_dec_and_test(&s_name_buf_cnt)
		       ? s_name_buf
		       : kmalloc(sizeof(s_name_buf), GFP_NOFS);

	if (name) {
		struct dentry *de = d_find_alias(inode);
		const u32 name_len = ARRAY_SIZE(s_name_buf) - 1;

		if (de) {
			spin_lock(&de->d_lock);
			snprintf(name, name_len, " \"%s\"", de->d_name.name);
			spin_unlock(&de->d_lock);
			name[name_len] = 0; /* To be sure. */
		} else {
			name[0] = 0;
		}
		dput(de); /* Cocci warns if placed in branch "if (de)" */
	}

	va_start(args, fmt);

	level = printk_get_level(fmt);
	vaf.fmt = printk_skip_level(fmt);
	vaf.va = &args;

	printk("%c%cntfs3: %s: ino=%lx,%s %pV\n", KERN_SOH_ASCII, level,
	       sb->s_id, inode->i_ino, name ? name : "", &vaf);

	va_end(args);

	atomic_inc(&s_name_buf_cnt);
	if (name != s_name_buf)
		kfree(name);
}
#endif

/*
 * Shared memory struct.
 *
 * On-disk ntfs's upcase table is created by ntfs formatter.
 * 'upcase' table is 128K bytes of memory.
 * We should read it into memory when mounting.
 * Several ntfs volumes likely use the same 'upcase' table.
 * It is good idea to share in-memory 'upcase' table between different volumes.
 * Unfortunately winxp/vista/win7 use different upcase tables.
 */
static DEFINE_SPINLOCK(s_shared_lock);

static struct {
	void *ptr;
	u32 len;
	int cnt;
} s_shared[8];

/*
 * ntfs_set_shared
 *
 * Return:
 * * @ptr - If pointer was saved in shared memory.
 * * NULL - If pointer was not shared.
 */
void *ntfs_set_shared(void *ptr, u32 bytes)
{
	void *ret = NULL;
	int i, j = -1;

	spin_lock(&s_shared_lock);
	for (i = 0; i < ARRAY_SIZE(s_shared); i++) {
		if (!s_shared[i].cnt) {
			j = i;
		} else if (bytes == s_shared[i].len &&
			   !memcmp(s_shared[i].ptr, ptr, bytes)) {
			s_shared[i].cnt += 1;
			ret = s_shared[i].ptr;
			break;
		}
	}

	if (!ret && j != -1) {
		s_shared[j].ptr = ptr;
		s_shared[j].len = bytes;
		s_shared[j].cnt = 1;
		ret = ptr;
	}
	spin_unlock(&s_shared_lock);

	return ret;
}

/*
 * ntfs_put_shared
 *
 * Return:
 * * @ptr - If pointer is not shared anymore.
 * * NULL - If pointer is still shared.
 */
void *ntfs_put_shared(void *ptr)
{
	void *ret = ptr;
	int i;

	spin_lock(&s_shared_lock);
	for (i = 0; i < ARRAY_SIZE(s_shared); i++) {
		if (s_shared[i].cnt && s_shared[i].ptr == ptr) {
			if (--s_shared[i].cnt)
				ret = NULL;
			break;
		}
	}
	spin_unlock(&s_shared_lock);

	return ret;
}

static inline void put_mount_options(struct ntfs_mount_options *options)
{
	kfree(options->nls_name);
	unload_nls(options->nls);
	kfree(options);
}

enum Opt {
	Opt_uid,
	Opt_gid,
	Opt_umask,
	Opt_dmask,
	Opt_fmask,
	Opt_immutable,
	Opt_discard,
	Opt_force,
	Opt_sparse,
	Opt_nohidden,
	Opt_showmeta,
	Opt_acl,
	Opt_iocharset,
	Opt_prealloc,
	Opt_noacsrules,
	Opt_err,
};

static const struct fs_parameter_spec ntfs_fs_parameters[] = {
	fsparam_u32("uid",			Opt_uid),
	fsparam_u32("gid",			Opt_gid),
	fsparam_u32oct("umask",			Opt_umask),
	fsparam_u32oct("dmask",			Opt_dmask),
	fsparam_u32oct("fmask",			Opt_fmask),
	fsparam_flag_no("sys_immutable",	Opt_immutable),
	fsparam_flag_no("discard",		Opt_discard),
	fsparam_flag_no("force",		Opt_force),
	fsparam_flag_no("sparse",		Opt_sparse),
	fsparam_flag_no("hidden",		Opt_nohidden),
	fsparam_flag_no("acl",			Opt_acl),
	fsparam_flag_no("showmeta",		Opt_showmeta),
	fsparam_flag_no("prealloc",		Opt_prealloc),
	fsparam_flag_no("acsrules",		Opt_noacsrules),
	fsparam_string("iocharset",		Opt_iocharset),
	{}
};

/*
 * Load nls table or if @nls is utf8 then return NULL.
 */
static struct nls_table *ntfs_load_nls(char *nls)
{
	struct nls_table *ret;

	if (!nls)
		nls = CONFIG_NLS_DEFAULT;

	if (strcmp(nls, "utf8") == 0)
		return NULL;

	if (strcmp(nls, CONFIG_NLS_DEFAULT) == 0)
		return load_nls_default();

	ret = load_nls(nls);
	if (ret)
		return ret;

	return ERR_PTR(-EINVAL);
}

static int ntfs_fs_parse_param(struct fs_context *fc,
			       struct fs_parameter *param)
{
	struct ntfs_mount_options *opts = fc->fs_private;
	struct fs_parse_result result;
	int opt;

	opt = fs_parse(fc, ntfs_fs_parameters, param, &result);
	if (opt < 0)
		return opt;

	switch (opt) {
	case Opt_uid:
		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
		if (!uid_valid(opts->fs_uid))
			return invalf(fc, "ntfs3: Invalid value for uid.");
		break;
	case Opt_gid:
		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
		if (!gid_valid(opts->fs_gid))
			return invalf(fc, "ntfs3: Invalid value for gid.");
		break;
	case Opt_umask:
		if (result.uint_32 & ~07777)
			return invalf(fc, "ntfs3: Invalid value for umask.");
		opts->fs_fmask_inv = ~result.uint_32;
		opts->fs_dmask_inv = ~result.uint_32;
		opts->fmask = 1;
		opts->dmask = 1;
		break;
	case Opt_dmask:
		if (result.uint_32 & ~07777)
			return invalf(fc, "ntfs3: Invalid value for dmask.");
		opts->fs_dmask_inv = ~result.uint_32;
		opts->dmask = 1;
		break;
	case Opt_fmask:
		if (result.uint_32 & ~07777)
			return invalf(fc, "ntfs3: Invalid value for fmask.");
		opts->fs_fmask_inv = ~result.uint_32;
		opts->fmask = 1;
		break;
	case Opt_immutable:
		opts->sys_immutable = result.negated ? 0 : 1;
		break;
	case Opt_discard:
		opts->discard = result.negated ? 0 : 1;
		break;
	case Opt_force:
		opts->force = result.negated ? 0 : 1;
		break;
	case Opt_sparse:
		opts->sparse = result.negated ?