path: root/fs/ntfs/ea.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Pocessing of EA's
 *
 * Part of this file is based on code from the NTFS-3G.
 *
 * Copyright (c) 2014-2021 Jean-Pierre Andre
 * Copyright (c) 2025 LG Electronics Co., Ltd.
 */

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

#include "layout.h"
#include "attrib.h"
#include "index.h"
#include "dir.h"
#include "ea.h"

static int ntfs_write_ea(struct ntfs_inode *ni, __le32 type, char *value, s64 ea_off,
		s64 ea_size, bool need_truncate)
{
	struct inode *ea_vi;
	int err = 0;
	s64 written;

	ea_vi = ntfs_attr_iget(VFS_I(ni), type, AT_UNNAMED, 0);
	if (IS_ERR(ea_vi))
		return PTR_ERR(ea_vi);

	written = ntfs_inode_attr_pwrite(ea_vi, ea_off, ea_size, value, false);
	if (written != ea_size)
		err = -EIO;
	else {
		struct ntfs_inode *ea_ni = NTFS_I(ea_vi);

		if (need_truncate && ea_ni->data_size > ea_off + ea_size)
			ntfs_attr_truncate(ea_ni, ea_off + ea_size);
		mark_mft_record_dirty(ni);
	}

	iput(ea_vi);
	return err;
}

static int ntfs_ea_lookup(char *ea_buf, s64 ea_buf_size, const char *name,
			  int name_len, s64 *ea_offset, s64 *ea_size)
{
	const struct ea_attr *p_ea;
	size_t actual_size;
	loff_t offset, p_ea_size;
	unsigned int next;

	if (ea_buf_size < sizeof(struct ea_attr))
		goto out;

	offset = 0;
	do {
		p_ea = (const struct ea_attr *)&ea_buf[offset];
		next = le32_to_cpu(p_ea->next_entry_offset);
		p_ea_size = next ? next : (ea_buf_size - offset);

		if (p_ea_size < sizeof(struct ea_attr) ||
		    offset + p_ea_size > ea_buf_size)
			break;

		if ((s64)p_ea->ea_name_length + 1 >
		    p_ea_size - offsetof(struct ea_attr, ea_name))
			break;

		actual_size = ALIGN(struct_size(p_ea, ea_name, 1 + p_ea->ea_name_length +
					le16_to_cpu(p_ea->ea_value_length)), 4);
		if (actual_size > p_ea_size)
			break;

		if (p_ea->ea_name_length == name_len &&
		    !memcmp(p_ea->ea_name, name, name_len)) {
			*ea_offset = offset;
			*ea_size = next ? next : actual_size;

			if (ea_buf_size < *ea_offset + *ea_size)
				goto out;

			return 0;
		}
		offset += next;
	} while (next > 0 && offset < ea_buf_size);

out:
	return -ENOENT;
}

/*
 * Return the existing EA
 *
 * The EA_INFORMATION is not examined and the consistency of the
 * existing EA is not checked.
 *
 * If successful, the full attribute is returned unchanged
 * and its size is returned.
 * If the designated buffer is too small, the needed size is
 * returned, and the buffer is left unchanged.
 * If there is an error, a negative value is returned and errno
 * is set according to the error.
 */
static int ntfs_get_ea(struct inode *inode, const char *name, size_t name_len,
		void *buffer, size_t size)
{
	struct ntfs_inode *ni = NTFS_I(inode);
	const struct ea_attr *p_ea;
	char *ea_buf;
	s64 ea_off, ea_size, all_ea_size, ea_info_size;
	int err;
	u32 ea_info_qlen;
	u16 ea_value_len;
	struct ea_information *p_ea_info;

	if (!NInoHasEA(ni))
		return -ENODATA;

	p_ea_info = ntfs_attr_readall(ni, AT_EA_INFORMATION, NULL, 0,
			&ea_info_size);
	if (!p_ea_info || ea_info_size != sizeof(struct ea_information)) {
		kvfree(p_ea_info);
		return -ENODATA;
	}

	ea_info_qlen = le32_to_cpu(p_ea_info->ea_query_length);
	kvfree(p_ea_info);

	ea_buf = ntfs_attr_readall(ni, AT_EA, NULL, 0, &all_ea_size);
	if (!ea_buf)
		return -ENODATA;

	if (ea_info_qlen > all_ea_size) {
		err = -EIO;
		goto free_ea_buf;