ntfs-3g/libntfs-3g/object_id.c

/**
 * object_id.c - Processing of object ids
 *
 *	This module is part of ntfs-3g library
 *
 * Copyright (c) 2009-2019 Jean-Pierre Andre
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_SYSMACROS_H
#include <sys/sysmacros.h>
#endif

#include "compat.h"
#include "types.h"
#include "debug.h"
#include "attrib.h"
#include "inode.h"
#include "dir.h"
#include "volume.h"
#include "mft.h"
#include "index.h"
#include "lcnalloc.h"
#include "object_id.h"
#include "logging.h"
#include "misc.h"
#include "xattrs.h"

/*
 *			Endianness considerations
 *
 *	According to RFC 4122, GUIDs should be printed with the most
 *	significant byte first, and the six fields be compared individually
 *	for ordering. RFC 4122 does not define the internal representation.
 *
 *	Windows apparently stores the first three fields in little endian
 *	order, and the last two fields in big endian order.
 *
 *	Here we always copy disk images with no endianness change,
 *	and, for indexing, GUIDs are compared as if they were a sequence
 *	of four little-endian unsigned 32 bit integers (as Windows
 *	does it that way.)
 *
 * --------------------- begin from RFC 4122 ----------------------
 * Consider each field of the UUID to be an unsigned integer as shown
 * in the table in section Section 4.1.2.  Then, to compare a pair of
 * UUIDs, arithmetically compare the corresponding fields from each
 * UUID in order of significance and according to their data type.
 * Two UUIDs are equal if and only if all the corresponding fields
 * are equal.
 *
 * UUIDs, as defined in this document, can also be ordered
 * lexicographically.  For a pair of UUIDs, the first one follows the
 * second if the most significant field in which the UUIDs differ is
 * greater for the first UUID.  The second precedes the first if the
 * most significant field in which the UUIDs differ is greater for
 * the second UUID.
 *
 * The fields are encoded as 16 octets, with the sizes and order of the
 * fields defined above, and with each field encoded with the Most
 * Significant Byte first (known as network byte order).  Note that the
 * field names, particularly for multiplexed fields, follow historical
 * practice.
 *
 * 0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                          time_low                             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |       time_mid                |         time_hi_and_version   |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                         node (2-5)                            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * ---------------------- end from RFC 4122 -----------------------
 */

typedef struct {
	union {
		/* alignment may be needed to evaluate collations */
		u32 alignment;
		GUID guid;
	} object_id;
} OBJECT_ID_INDEX_KEY;

typedef struct {
	le64 file_id;
	GUID birth_volume_id;
	GUID birth_object_id;
	GUID domain_id;
} OBJECT_ID_INDEX_DATA; // known as OBJ_ID_INDEX_DATA

struct OBJECT_ID_INDEX {		/* index entry in $Extend/$ObjId */
	INDEX_ENTRY_HEADER header;
	OBJECT_ID_INDEX_KEY key;
	OBJECT_ID_INDEX_DATA data;
} ;

static ntfschar objid_index_name[] = { const_cpu_to_le16('$'),
					 const_cpu_to_le16('O') };

/*
 *			Set the index for a new object id
 *
 *	Returns 0 if success
 *		-1 if failure, explained by errno
 */

static int set_object_id_index(ntfs_inode *ni, ntfs_index_context *xo,
			const OBJECT_ID_ATTR *object_id)
{
	struct OBJECT_ID_INDEX indx;
	u64 file_id_cpu;
	le64 file_id;
	le16 seqn;

	seqn = ni->mrec->sequence_number;
	file_id_cpu = MK_MREF(ni->mft_no,le16_to_cpu(seqn));
	file_id = cpu_to_le64(file_id_cpu);
	indx.header.data_offset = const_cpu_to_le16(
					sizeof(INDEX_ENTRY_HEADER)
					+ sizeof(OBJECT_ID_INDEX_KEY));
	indx.header.data_length = const_cpu_to_le16(
					sizeof(OBJECT_ID_INDEX_DATA));
	indx.header.reservedV = const_cpu_to_le32(0);
	indx.header.length = const_cpu_to_le16(
					sizeof(struct OBJECT_ID_INDEX));
	indx.header.key_length = const_cpu_to_le16(
					sizeof(OBJECT_ID_INDEX_KEY));
	indx.header.flags = const_cpu_to_le16(0);
	indx.header.reserved = const_cpu_to_le16(0);

	memcpy(&indx.key.object_id,object_id,sizeof(GUID));

	indx.data.file_id = file_id;
	memcpy(&indx.data.birth_volume_id,
			&object_id->birth_volume_id,sizeof(GUID));
	memcpy(&indx.data.birth_object_id,
			&object_id->birth_object_id,sizeof(GUID));
	memcpy(&indx.data.domain_id,
			&object_id->domain_id,sizeof(GUID));
	ntfs_index_ctx_reinit(xo);
	return (ntfs_ie_add(xo,(INDEX_ENTRY*)&indx));
}

/*
 *		Open the $Extend/$ObjId file and its index
 *
 *	Return the index context if opened
 *		or NULL if an error occurred (errno tells why)
 *
 *	The index has to be freed and inode closed when not needed any more.
 */

static ntfs_index_context *open_object_id_index(ntfs_volume *vol)
{
	u64 inum;
	ntfs_inode *ni;
	ntfs_inode *dir_ni;
	ntfs_index_context *xo;

		/* do not use path_name_to inode - could reopen root */
	dir_ni = ntfs_inode_open(vol, FILE_Extend);
	ni = (ntfs_inode*)NULL;
	if (dir_ni) {
		inum = ntfs_inode_lookup_by_mbsname(dir_ni,"$ObjId");
		if (inum != (u64)-1)
			ni = ntfs_inode_open(vol, inum);
		ntfs_inode_close(dir_ni);
	}
	if (ni) {
		xo = ntfs_index_ctx_get(ni, objid_index_name, 2);
		if (!xo) {
			ntfs_inode_close(ni);
		}
	} else
		xo = (ntfs_index_context*)NULL;
	return (xo);
}


/*
 *		Merge object_id data stored in the index into
 *	a full object_id struct.
 *
 *	returns 0 if merging successful
 *		-1 if no data could be merged. This is generally not an error
 */

static int merge_index_data(ntfs_inode *ni,
			const OBJECT_ID_ATTR *objectid_attr,
			OBJECT_ID_ATTR *full_objectid)
{
	OBJECT_ID_INDEX_KEY key;
	struct OBJECT_ID_INDEX *entry;
	ntfs_index_context *xo;
	ntfs_inode *xoni;
	int res;

	res = -1;
	xo = open_object_id_index(ni->vol);
	if (xo) {
		memcpy(&key.object_id,objectid_attr,sizeof(GUID));
		if (!ntfs_index_lookup(&key,
				sizeof(OBJECT_ID_INDEX_KEY), xo)) {
			entry = (struct OBJECT_ID_INDEX*)xo->entry;
			/* make sure inode numbers match */
			if (entry
			    && (MREF(le64_to_cpu(entry->data.file_id))
					== ni->mft_no)) {
				memcpy(&full_objectid->birth_volume_id,
						&entry->data.birth_volume_id,
						sizeof(GUID));
				memcpy(&full_objectid->birth_object_id,
						&entry->data.birth_object_id,
						sizeof(GUID));
				memcpy(&full_objectid->domain_id,
						&entry->data.domain_id,
						sizeof(GUID));
				res = 0;
			}
		}
		xoni = xo->ni;
		ntfs_index_ctx_put(xo);
		ntfs_inode_close(xoni);
	}
	return (res);
}


/*
 *		Remove an object id index entry if attribute present
 *
 *	Returns the size of existing object id
 *			(the existing object_d is returned)
 *		-1 if failure, explained by errno
 */

static int remove_object_id_index(ntfs_attr *na, ntfs_index_context *xo,
				OBJECT_ID_ATTR *old_attr)
{
	OBJECT_ID_INDEX_KEY key;
	struct OBJECT_ID_INDEX *entry;
	s64 size;
	int ret;

	ret = na->data_size;
	if (ret) {
			/* read the existing object id attribute */
		size = ntfs_attr_pread(na, 0, sizeof(GUID), old_attr);
		if (size >= (s64)sizeof(GUID)) {
			memcpy(&key.object_id,
				&old_attr->object_id,sizeof(GUID));
			if (!ntfs_index_lookup(&key,
					sizeof(OBJECT_ID_INDEX_KEY), xo)) {
				entry = (struct OBJECT_ID_INDEX*)xo->entry;
				memcpy(&old_attr->birth_volume_id,
					&entry->data.birth_volume_id,
					sizeof(GUID));
				memcpy(&old_attr->birth_object_id,
					&entry->data.birth_object_id,
					sizeof(GUID));
				memcpy(&old_attr->domain_id,
					&entry->data.domain_id,
					sizeof(GUID));
				if (ntfs_index_rm(xo))
					ret = -1;
			}
		} else {
			ret = -1;
			errno = ENODATA;
		}
	}
	return (ret);
}


/*
 *		Update the object id and index
 *
 *	The object_id attribute should have been created and the
 *	non-duplication of the GUID should have been checked before.
 *
 *	Returns 0 if success
 *		-1 if failure, explained by errno
 *	If could not remove the existing index, nothing is done,
 *	If could not write the new data, no index entry is inserted
 *	If failed to insert the index, data is removed
 */

static int update_object_id(ntfs_inode *ni, ntfs_index_context *xo,
			const OBJECT_ID_ATTR *value, size_t size)
{
	OBJECT_ID_ATTR old_attr;
	ntfs_attr *na;
	int oldsize;
	int written;
	int res;

	res = 0;

	na = ntfs_attr_open(ni, AT_OBJECT_ID, AT_UNNAMED, 0);
	if (na) {
		memset(&old_attr, 0, sizeof(OBJECT_ID_ATTR));
			/* remove the existing index entry */
		oldsize = remove_object_id_index(na,xo,&old_attr);
		if (oldsize < 0)
			res = -1;
		else {
			/* resize attribute */
			res = ntfs_attr_truncate(na, (s64)sizeof(GUID));
				/* write the object_id in attribute */
			if (!res && value) {
				written = (int)ntfs_attr_pwrite(na,
					(s64)0, (s64)sizeof(GUID),
					&value->object_id);
				if (written != (s64)sizeof(GUID)) {
					ntfs_log_error("Failed to update "
							"object id\n");
					errno = EIO;
					res = -1;
				}
			}
				/* overwrite index data with new value */
			memcpy(&old_attr, value,
				(size < sizeof(OBJECT_ID_ATTR)
					? size : sizeof(OBJECT_ID_ATTR)));
			if (!res
			    && set_object_id_index(ni,xo,&old_attr)) {
				/*
				 * If cannot index, try to remove the object
				 * id and log the error. There will be an
				 * inconsistency if removal fails.
				 */
				ntfs_attr_rm(na);
				ntfs_log_error("Failed to index object id."
						" Possible corruption.\n");
			}
		}
		ntfs_attr_close(na);
		NInoSetDirty(ni);
	} else
		res = -1;
	return (res);
}

/*
 *		Add a (dummy) object id to an inode if it does not exist
 *
 *	returns 0 if attribute was inserted (or already present)
 *		-1 if adding failed (explained by errno)
 */

static int add_object_id(ntfs_inode *ni, int flags)
{
	int res;
	u8 dummy;

	res = -1; /* default return */
	if (!ntfs_attr_exist(ni,AT_OBJECT_ID, AT_UNNAMED,0)) {
		if (!(flags & XATTR_REPLACE)) {
			/*
			 * no object id attribute : add one,
			 * apparently, this does not feed the new value in
			 * Note : NTFS version must be >= 3
			 */
			if (ni->vol->major_ver >= 3) {
				res = ntfs_attr_add(ni, AT_OBJECT_ID,
						AT_UNNAMED, 0, &dummy, (s64)0);
				NInoSetDirty(ni);
			} else
				errno = EOPNOTSUPP;
		} else
			errno = ENODATA;
	} else {
		if (flags & XATTR_CREATE)
			errno = EEXIST;
		else
			res = 0;
	}
	return (res);
}


/*
 *		Delete an object_id index entry
 *
 *	Returns 0 if success
 *		-1 if failure, explained by errno
 */

int ntfs_delete_object_id_index(ntfs_inode *ni)
{
	ntfs_index_context *xo;
	ntfs_inode *xoni;
	ntfs_attr *na;
	OBJECT_ID_ATTR old_attr;
	int res;

	res = 0;
	na = ntfs_attr_open(ni, AT_OBJECT_ID, AT_UNNAMED, 0);
	if (na) {
			/*
			 * read the existing object id
			 * and un-index it
			 */
		xo = open_object_id_index(ni->vol);
		if (xo) {
			if (remove_object_id_index(na,xo,&old_attr) < 0)
				res = -1;
			xoni = xo->ni;
			ntfs_index_entry_mark_dirty(xo);
			NInoSetDirty(xoni);
			ntfs_index_ctx_put(xo);
			ntfs_inode_close(xoni);
		}
		ntfs_attr_close(na);
	}
	return (res);
}


/*
 *		Get the ntfs object id into an extended attribute
 *
 *	If present, the object_id from the attribute and the GUIDs
 *	from the index are returned (formatted as OBJECT_ID_ATTR)
 *
 *	Returns the global size (can be 0, 16 or 64)
 *		and the buffer is updated if it is long enough
 */

int ntfs_get_ntfs_object_id(ntfs_inode *ni, char *value, size_t size)
{
	OBJECT_ID_ATTR full_objectid;
	OBJECT_ID_ATTR *objectid_attr;
	s64 attr_size;
	int full_size;

	full_size = 0;	/* default to no data and some error to be defined */
	if (ni) {
		objectid_attr = (OBJECT_ID_ATTR*)ntfs_attr_readall(ni,
			AT_OBJECT_ID,(ntfschar*)NULL, 0, &attr_size);
		if (objectid_attr) {
				/* restrict to only GUID present in attr */
			if (attr_size == sizeof(GUID)) {
				memcpy(&full_objectid.object_id,
						objectid_attr,sizeof(GUID));
				full_size = sizeof(GUID);
					/* get data from index, if any */
				if (!merge_index_data(ni, objectid_attr,
						&full_objectid)) {
					full_size = sizeof(OBJECT_ID_ATTR);
				}
				if (full_size <= (s64)size) {
					if (value)
						memcpy(value,&full_objectid,
							full_size);
					else
						errno = EINVAL;
				}
			} else {
			/* unexpected size, better return unsupported */
				errno = EOPNOTSUPP;
				full_size = 0;
			}
			free(objectid_attr);
		} else
			errno = ENODATA;
	}
	return (full_size ? (int)full_size : -errno);
}

/*
 *		Set the object id from an extended attribute
 *
 *	The first 16 bytes are the new object id, they can be followed
 *	by the birth volume id, the birth object id and the domain id.
 *	If they are not present, their previous value is kept.
 *	Only the object id is stored into the attribute, all the fields
 *	are stored into the index.
 *
 *	Returns 0, or -1 if there is a problem
 */

int ntfs_set_ntfs_object_id(ntfs_inode *ni,
			const char *value, size_t size, int flags)
{
	OBJECT_ID_INDEX_KEY key;
	ntfs_inode *xoni;
	ntfs_index_context *xo;
	int res;

	res = 0;
	if (ni && value && (size >= sizeof(GUID))) {
		xo = open_object_id_index(ni->vol);
		if (xo) {
			/* make sure the GUID was not used elsewhere */
			memcpy(&key.object_id, value, sizeof(GUID));
			if ((ntfs_index_lookup(&key,
					sizeof(OBJECT_ID_INDEX_KEY), xo))
			    || (MREF_LE(((struct OBJECT_ID_INDEX*)xo->entry)
					->data.file_id) == ni->mft_no)) {
				ntfs_index_ctx_reinit(xo);
				res = add_object_id(ni, flags);
				if (!res) {
						/* update value and index */
					res = update_object_id(ni,xo,
						(const OBJECT_ID_ATTR*)value,
						size);
				}
			} else {
					/* GUID is present elsewhere */
				res = -1;
				errno = EEXIST;
			}
			xoni = xo->ni;
			ntfs_index_entry_mark_dirty(xo);
			NInoSetDirty(xoni);
			ntfs_index_ctx_put(xo);
			ntfs_inode_close(xoni);
		} else {
			res = -1;
		}
	} else {
		errno = EINVAL;
		res = -1;
	}
	return (res ? -1 : 0);
}

/*
 *		Remove the object id
 *
 *	Returns 0, or -1 if there is a problem
 */

int ntfs_remove_ntfs_object_id(ntfs_inode *ni)
{
	int res;
	int olderrno;
	ntfs_attr *na;
	ntfs_inode *xoni;
	ntfs_index_context *xo;
	int oldsize;
	OBJECT_ID_ATTR old_attr;

	res = 0;
	if (ni) {
		/*
		 * open and delete the object id
		 */
		na = ntfs_attr_open(ni, AT_OBJECT_ID,
			AT_UNNAMED,0);
		if (na) {
			/* first remove index (old object id needed) */
			xo = open_object_id_index(ni->vol);
			if (xo) {
				oldsize = remove_object_id_index(na,xo,
						&old_attr);
				if (oldsize < 0) {
					res = -1;
				} else {
					/* now remove attribute */
					res = ntfs_attr_rm(na);
					if (res
					    && (oldsize > (int)sizeof(GUID))) {
					/*
					 * If we could not remove the
					 * attribute, try to restore the
					 * index and log the error. There
					 * will be an inconsistency if
					 * the reindexing fails.
					 */
						set_object_id_index(ni, xo,
							&old_attr);
						ntfs_log_error(
						"Failed to remove object id."
						" Possible corruption.\n");
					}
				}

				xoni = xo->ni;
				ntfs_index_entry_mark_dirty(xo);
				NInoSetDirty(xoni);
				ntfs_index_ctx_put(xo);
				ntfs_inode_close(xoni);
			}
			olderrno = errno;
			ntfs_attr_close(na);
					/* avoid errno pollution */
			if (errno == ENOENT)
				errno = olderrno;
		} else {
			errno = ENODATA;
			res = -1;
		}
		NInoSetDirty(ni);
	} else {
		errno = EINVAL;
		res = -1;
	}
	return (res ? -1 : 0);
}