path: root/fs/ntfs3/xattr.c

// SPDX-License-Identifier: GPL-2.0
/*
 *
 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
 *
 */

#include <linux/fs.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>

#include "debug.h"
#include "ntfs.h"
#include "ntfs_fs.h"

// clang-format off
#define SYSTEM_DOS_ATTRIB     "system.dos_attrib"
#define SYSTEM_NTFS_ATTRIB    "system.ntfs_attrib"
#define SYSTEM_NTFS_ATTRIB_BE "system.ntfs_attrib_be"
#define SYSTEM_NTFS_SECURITY  "system.ntfs_security"
// clang-format on

static inline size_t unpacked_ea_size(const struct EA_FULL *ea)
{
	return ea->size ? le32_to_cpu(ea->size) :
			  ALIGN(struct_size(ea, name,
					    1 + ea->name_len +
						    le16_to_cpu(ea->elength)),
				4);
}

static inline size_t packed_ea_size(const struct EA_FULL *ea)
{
	return struct_size(ea, name,
			   1 + ea->name_len + le16_to_cpu(ea->elength)) -
	       offsetof(struct EA_FULL, flags);
}

/*
 * find_ea
 *
 * Assume there is at least one xattr in the list.
 */
static inline bool find_ea(const struct EA_FULL *ea_all, u32 bytes,
			   const char *name, u8 name_len, u32 *off, u32 *ea_sz)
{
	u32 ea_size;

	*off = 0;
	if (!ea_all)
		return false;

	for (; *off < bytes; *off += ea_size) {
		const struct EA_FULL *ea = Add2Ptr(ea_all, *off);
		ea_size = unpacked_ea_size(ea);
		if (ea->name_len == name_len &&
		    !memcmp(ea->name, name, name_len)) {
			if (ea_sz)
				*ea_sz = ea_size;
			return true;
		}
	}

	return false;
}

/*
 * ntfs_read_ea - Read all extended attributes.
 * @ea:		New allocated memory.
 * @info:	Pointer into resident data.
 */
static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,
			size_t add_bytes, const struct EA_INFO **info)
{
	int err = -EINVAL;
	struct ntfs_sb_info *sbi = ni->mi.sbi;
	struct ATTR_LIST_ENTRY *le = NULL;
	struct ATTRIB *attr_info, *attr_ea;
	void *ea_p;
	u32 size, off, ea_size;

	static_assert(le32_to_cpu(ATTR_EA_INFO) < le32_to_cpu(ATTR_EA));

	*ea = NULL;
	*info = NULL;

	attr_info =
		ni_find_attr(ni, NULL, &le, ATTR_EA_INFO, NULL, 0, NULL, NULL);
	attr_ea =
		ni_find_attr(ni, attr_info, &le, ATTR_EA, NULL, 0, NULL, NULL);

	if (!attr_ea || !attr_info)
		return 0;

	*info = resident_data_ex(attr_info, sizeof(struct EA_INFO));
	if (!*info)
		goto out;

	/* Check Ea limit. */
	size = le32_to_cpu((*info)->size);
	if (size > sbi->ea_max_size) {
		err = -EFBIG;
		goto out;
	}

	if (attr_size(attr_ea) > sbi->ea_max_size) {
		err = -EFBIG;
		goto out;
	}

	if (!size) {
		/* EA info persists, but xattr is empty. Looks like EA problem. */
		goto out;
	}

	/* Allocate memory for packed Ea. */
	ea_p = kmalloc(size_add(size, add_bytes), GFP_NOFS);
	if (!ea_p)
		return -ENOMEM;

	if (attr_ea->non_res) {
		struct runs_tree run;

		run_init(&run);

		err = attr_load_runs_range(ni, ATTR_EA, NULL, 0, &run, 0, size);
		if (!err)
			err = ntfs_read_run_nb(sbi, &run, 0, ea_p, size, NULL);
		run_close(&run);

		if (err)
			goto out1;
	} else {
		void *p = resident_data_ex(attr_ea, size);

		if (!p)
			goto out1;
		memcpy(ea_p, p, size);
	}

	memset(Add2Ptr(ea_p, size), 0, add_bytes);

	err = -EINVAL;
	/* Check all attributes for consistency. */
	for (off = 0; off < size; off += ea_size) {
		const struct EA_FULL *ef = Add2Ptr(ea_p, off);
		u32 bytes = size - off;

		/* Check if we can use field ea->size. */
		if (bytes < sizeof(ef->size))
			goto out1;

		if (ef->size) {
			ea_size = le32_to_cpu(ef->size);
			if (ea_size > bytes)
				goto out1;
			continue;
		}

		/* Check if we can use fields ef->name_len and ef->elength. */
		if (bytes < offsetof(struct EA_FULL, name))
			goto out1;

		ea_size = ALIGN(struct_size(ef, name,
					    1 + ef->name_len +
						    le16_to_cpu(ef->elength)),
				4);
		if (ea_size > bytes)
			goto out1;
	}

	*ea = ea_p;
	return 0;

out1:
	kfree(ea_p);
out:
	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
	return err;
}

/*