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https://git.code.sf.net/p/ntfs-3g/ntfs-3g.git
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894b7dd36e
On startup make sure the lcns of the MFT and the MFTMirr are not null and they are different, so that the mounting is denied gracefully if they are.
309 lines
11 KiB
C
309 lines
11 KiB
C
/**
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* bootsect.c - Boot sector handling code. Originated from the Linux-NTFS project.
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*
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* Copyright (c) 2000-2006 Anton Altaparmakov
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* Copyright (c) 2003-2008 Szabolcs Szakacsits
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* Copyright (c) 2005 Yura Pakhuchiy
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program/include file is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (in the main directory of the NTFS-3G
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* distribution in the file COPYING); if not, write to the Free Software
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* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifdef HAVE_STDIO_H
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#include <stdio.h>
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#endif
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include "param.h"
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#include "compat.h"
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#include "bootsect.h"
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#include "debug.h"
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#include "logging.h"
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/**
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* ntfs_boot_sector_is_ntfs - check if buffer contains a valid ntfs boot sector
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* @b: buffer containing putative boot sector to analyze
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* @silent: if zero, output progress messages to stderr
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*
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* Check if the buffer @b contains a valid ntfs boot sector. The buffer @b
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* must be at least 512 bytes in size.
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*
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* If @silent is zero, output progress messages to stderr. Otherwise, do not
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* output any messages (except when configured with --enable-debug in which
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* case warning/debug messages may be displayed).
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*
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* Return TRUE if @b contains a valid ntfs boot sector and FALSE if not.
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*/
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BOOL ntfs_boot_sector_is_ntfs(NTFS_BOOT_SECTOR *b)
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{
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u32 i;
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BOOL ret = FALSE;
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u16 sectors_per_cluster;
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ntfs_log_debug("Beginning bootsector check.\n");
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ntfs_log_debug("Checking OEMid, NTFS signature.\n");
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if (b->oem_id != const_cpu_to_le64(0x202020205346544eULL)) { /* "NTFS " */
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ntfs_log_error("NTFS signature is missing.\n");
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goto not_ntfs;
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}
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ntfs_log_debug("Checking bytes per sector.\n");
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if (le16_to_cpu(b->bpb.bytes_per_sector) < 256 ||
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le16_to_cpu(b->bpb.bytes_per_sector) > 4096) {
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ntfs_log_error("Unexpected bytes per sector value (%d).\n",
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le16_to_cpu(b->bpb.bytes_per_sector));
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goto not_ntfs;
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}
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ntfs_log_debug("Checking sectors per cluster.\n");
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switch (b->bpb.sectors_per_cluster) {
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case 1: case 2: case 4: case 8: case 16: case 32: case 64: case 128:
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break;
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default:
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if ((b->bpb.sectors_per_cluster < 240)
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|| (b->bpb.sectors_per_cluster > 253)) {
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if (b->bpb.sectors_per_cluster > 128)
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ntfs_log_error("Unexpected sectors"
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" per cluster value (code 0x%x)\n",
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b->bpb.sectors_per_cluster);
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else
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ntfs_log_error("Unexpected sectors"
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" per cluster value (%d).\n",
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b->bpb.sectors_per_cluster);
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goto not_ntfs;
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}
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}
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ntfs_log_debug("Checking cluster size.\n");
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if (b->bpb.sectors_per_cluster > 128)
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sectors_per_cluster = 1 << (256 - b->bpb.sectors_per_cluster);
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else
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sectors_per_cluster = b->bpb.sectors_per_cluster;
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i = (u32)le16_to_cpu(b->bpb.bytes_per_sector) * sectors_per_cluster;
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if (i > NTFS_MAX_CLUSTER_SIZE) {
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ntfs_log_error("Unexpected cluster size (%d).\n", i);
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goto not_ntfs;
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}
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ntfs_log_debug("Checking reserved fields are zero.\n");
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if (le16_to_cpu(b->bpb.reserved_sectors) ||
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le16_to_cpu(b->bpb.root_entries) ||
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le16_to_cpu(b->bpb.sectors) ||
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le16_to_cpu(b->bpb.sectors_per_fat) ||
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le32_to_cpu(b->bpb.large_sectors) ||
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b->bpb.fats) {
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ntfs_log_error("Reserved fields aren't zero "
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"(%d, %d, %d, %d, %d, %d).\n",
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le16_to_cpu(b->bpb.reserved_sectors),
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le16_to_cpu(b->bpb.root_entries),
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le16_to_cpu(b->bpb.sectors),
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le16_to_cpu(b->bpb.sectors_per_fat),
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le32_to_cpu(b->bpb.large_sectors),
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b->bpb.fats);
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goto not_ntfs;
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}
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ntfs_log_debug("Checking clusters per mft record.\n");
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if ((u8)b->clusters_per_mft_record < 0xe1 ||
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(u8)b->clusters_per_mft_record > 0xf7) {
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switch (b->clusters_per_mft_record) {
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case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40:
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break;
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default:
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ntfs_log_error("Unexpected clusters per mft record "
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"(%d).\n", b->clusters_per_mft_record);
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goto not_ntfs;
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}
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}
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ntfs_log_debug("Checking clusters per index block.\n");
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if ((u8)b->clusters_per_index_record < 0xe1 ||
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(u8)b->clusters_per_index_record > 0xf7) {
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switch (b->clusters_per_index_record) {
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case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40:
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break;
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default:
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ntfs_log_error("Unexpected clusters per index record "
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"(%d).\n", b->clusters_per_index_record);
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goto not_ntfs;
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}
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}
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/* MFT and MFTMirr may not overlap the boot sector or be the same */
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if (!b->mft_lcn || !b->mftmirr_lcn || (b->mft_lcn == b->mftmirr_lcn)) {
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ntfs_log_error("Invalid location of MFT or MFTMirr.\n");
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goto not_ntfs;
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}
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if (b->end_of_sector_marker != const_cpu_to_le16(0xaa55))
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ntfs_log_debug("Warning: Bootsector has invalid end of sector "
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"marker.\n");
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ntfs_log_debug("Bootsector check completed successfully.\n");
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ret = TRUE;
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not_ntfs:
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return ret;
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}
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static const char *last_sector_error =
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"HINTS: Either the volume is a RAID/LDM but it wasn't setup yet,\n"
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" or it was not setup correctly (e.g. by not using mdadm --build ...),\n"
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" or a wrong device is tried to be mounted,\n"
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" or the partition table is corrupt (partition is smaller than NTFS),\n"
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" or the NTFS boot sector is corrupt (NTFS size is not valid).\n";
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/**
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* ntfs_boot_sector_parse - setup an ntfs volume from an ntfs boot sector
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* @vol: ntfs_volume to setup
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* @bs: buffer containing ntfs boot sector to parse
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*
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* Parse the ntfs bootsector @bs and setup the ntfs volume @vol with the
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* obtained values.
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*
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* Return 0 on success or -1 on error with errno set to the error code EINVAL.
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*/
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int ntfs_boot_sector_parse(ntfs_volume *vol, const NTFS_BOOT_SECTOR *bs)
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{
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s64 sectors;
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u16 sectors_per_cluster;
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s8 c;
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/* We return -1 with errno = EINVAL on error. */
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errno = EINVAL;
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vol->sector_size = le16_to_cpu(bs->bpb.bytes_per_sector);
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vol->sector_size_bits = ffs(vol->sector_size) - 1;
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ntfs_log_debug("SectorSize = 0x%x\n", vol->sector_size);
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ntfs_log_debug("SectorSizeBits = %u\n", vol->sector_size_bits);
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/*
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* The bounds checks on mft_lcn and mft_mirr_lcn (i.e. them being
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* below or equal the number_of_clusters) really belong in the
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* ntfs_boot_sector_is_ntfs but in this way we can just do this once.
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*/
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if (bs->bpb.sectors_per_cluster > 128)
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sectors_per_cluster = 1 << (256 - bs->bpb.sectors_per_cluster);
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else
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sectors_per_cluster = bs->bpb.sectors_per_cluster;
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ntfs_log_debug("SectorsPerCluster = 0x%x\n", sectors_per_cluster);
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if (sectors_per_cluster & (sectors_per_cluster - 1)) {
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ntfs_log_error("sectors_per_cluster (%d) is not a power of 2."
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"\n", sectors_per_cluster);
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return -1;
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}
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sectors = sle64_to_cpu(bs->number_of_sectors);
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ntfs_log_debug("NumberOfSectors = %lld\n", (long long)sectors);
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if (!sectors) {
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ntfs_log_error("Volume size is set to zero.\n");
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return -1;
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}
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if (vol->dev->d_ops->seek(vol->dev,
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(sectors - 1) << vol->sector_size_bits,
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SEEK_SET) == -1) {
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ntfs_log_perror("Failed to read last sector (%lld)",
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(long long)(sectors - 1));
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ntfs_log_error("%s", last_sector_error);
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return -1;
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}
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vol->nr_clusters = sectors >> (ffs(sectors_per_cluster) - 1);
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vol->mft_lcn = sle64_to_cpu(bs->mft_lcn);
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vol->mftmirr_lcn = sle64_to_cpu(bs->mftmirr_lcn);
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ntfs_log_debug("MFT LCN = %lld\n", (long long)vol->mft_lcn);
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ntfs_log_debug("MFTMirr LCN = %lld\n", (long long)vol->mftmirr_lcn);
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if ((vol->mft_lcn < 0 || vol->mft_lcn > vol->nr_clusters) ||
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(vol->mftmirr_lcn < 0 || vol->mftmirr_lcn > vol->nr_clusters)) {
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ntfs_log_error("$MFT LCN (%lld) or $MFTMirr LCN (%lld) is "
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"greater than the number of clusters (%lld).\n",
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(long long)vol->mft_lcn, (long long)vol->mftmirr_lcn,
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(long long)vol->nr_clusters);
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return -1;
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}
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vol->cluster_size = sectors_per_cluster * vol->sector_size;
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if (vol->cluster_size & (vol->cluster_size - 1)) {
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ntfs_log_error("cluster_size (%d) is not a power of 2.\n",
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vol->cluster_size);
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return -1;
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}
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vol->cluster_size_bits = ffs(vol->cluster_size) - 1;
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/*
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* Need to get the clusters per mft record and handle it if it is
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* negative. Then calculate the mft_record_size. A value of 0x80 is
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* illegal, thus signed char is actually ok!
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*/
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c = bs->clusters_per_mft_record;
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ntfs_log_debug("ClusterSize = 0x%x\n", (unsigned)vol->cluster_size);
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ntfs_log_debug("ClusterSizeBits = %u\n", vol->cluster_size_bits);
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ntfs_log_debug("ClustersPerMftRecord = 0x%x\n", c);
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/*
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* When clusters_per_mft_record is negative, it means that it is to
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* be taken to be the negative base 2 logarithm of the mft_record_size
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* min bytes. Then:
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* mft_record_size = 2^(-clusters_per_mft_record) bytes.
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*/
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if (c < 0)
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vol->mft_record_size = 1 << -c;
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else
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vol->mft_record_size = c << vol->cluster_size_bits;
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if (vol->mft_record_size & (vol->mft_record_size - 1)) {
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ntfs_log_error("mft_record_size (%d) is not a power of 2.\n",
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vol->mft_record_size);
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return -1;
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}
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vol->mft_record_size_bits = ffs(vol->mft_record_size) - 1;
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ntfs_log_debug("MftRecordSize = 0x%x\n", (unsigned)vol->mft_record_size);
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ntfs_log_debug("MftRecordSizeBits = %u\n", vol->mft_record_size_bits);
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/* Same as above for INDX record. */
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c = bs->clusters_per_index_record;
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ntfs_log_debug("ClustersPerINDXRecord = 0x%x\n", c);
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if (c < 0)
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vol->indx_record_size = 1 << -c;
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else
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vol->indx_record_size = c << vol->cluster_size_bits;
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vol->indx_record_size_bits = ffs(vol->indx_record_size) - 1;
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ntfs_log_debug("INDXRecordSize = 0x%x\n", (unsigned)vol->indx_record_size);
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ntfs_log_debug("INDXRecordSizeBits = %u\n", vol->indx_record_size_bits);
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/*
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* Work out the size of the MFT mirror in number of mft records. If the
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* cluster size is less than or equal to the size taken by four mft
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* records, the mft mirror stores the first four mft records. If the
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* cluster size is bigger than the size taken by four mft records, the
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* mft mirror contains as many mft records as will fit into one
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* cluster.
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*/
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if (vol->cluster_size <= 4 * vol->mft_record_size)
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vol->mftmirr_size = 4;
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else
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vol->mftmirr_size = vol->cluster_size / vol->mft_record_size;
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return 0;
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}
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