/** * bootsect.c - Boot sector handling code. Originated from the Linux-NTFS project. * * Copyright (c) 2000-2006 Anton Altaparmakov * Copyright (c) 2003-2008 Szabolcs Szakacsits * Copyright (c) 2005 Yura Pakhuchiy * * 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_STDIO_H #include #endif #ifdef HAVE_STDLIB_H #include #endif #ifdef HAVE_STRING_H #include #endif #ifdef HAVE_ERRNO_H #include #endif #include "compat.h" #include "bootsect.h" #include "debug.h" #include "logging.h" /** * ntfs_boot_sector_is_ntfs - check if buffer contains a valid ntfs boot sector * @b: buffer containing putative boot sector to analyze * @silent: if zero, output progress messages to stderr * * Check if the buffer @b contains a valid ntfs boot sector. The buffer @b * must be at least 512 bytes in size. * * If @silent is zero, output progress messages to stderr. Otherwise, do not * output any messages (except when configured with --enable-debug in which * case warning/debug messages may be displayed). * * Return TRUE if @b contains a valid ntfs boot sector and FALSE if not. */ BOOL ntfs_boot_sector_is_ntfs(NTFS_BOOT_SECTOR *b) { u32 i; BOOL ret = FALSE; ntfs_log_debug("Beginning bootsector check.\n"); ntfs_log_debug("Checking OEMid, NTFS signature.\n"); ntfs_log_debug((char *)b); if (b->oem_id != cpu_to_le64(0x202020205346544eULL)) { /* "NTFS " */ ntfs_log_error("NTFS signature is missing.\n"); goto not_ntfs; } ntfs_log_debug("Checking bytes per sector.\n"); if (le16_to_cpu(b->bpb.bytes_per_sector) < 256 || le16_to_cpu(b->bpb.bytes_per_sector) > 4096) { ntfs_log_error("Unexpected bytes per sector value (%d).\n", le16_to_cpu(b->bpb.bytes_per_sector)); goto not_ntfs; } ntfs_log_debug("Checking sectors per cluster.\n"); switch (b->bpb.sectors_per_cluster) { case 1: case 2: case 4: case 8: case 16: case 32: case 64: case 128: break; default: ntfs_log_error("Unexpected sectors per cluster value (%d).\n", b->bpb.sectors_per_cluster); goto not_ntfs; } ntfs_log_debug("Checking cluster size.\n"); i = (u32)le16_to_cpu(b->bpb.bytes_per_sector) * b->bpb.sectors_per_cluster; if (i > 65536) { ntfs_log_error("Unexpected cluster size (%d).\n", i); goto not_ntfs; } ntfs_log_debug("Checking reserved fields are zero.\n"); if (le16_to_cpu(b->bpb.reserved_sectors) || le16_to_cpu(b->bpb.root_entries) || le16_to_cpu(b->bpb.sectors) || le16_to_cpu(b->bpb.sectors_per_fat) || le32_to_cpu(b->bpb.large_sectors) || b->bpb.fats) { ntfs_log_error("Reserved fields aren't zero " "(%d, %d, %d, %d, %d, %d).\n", le16_to_cpu(b->bpb.reserved_sectors), le16_to_cpu(b->bpb.root_entries), le16_to_cpu(b->bpb.sectors), le16_to_cpu(b->bpb.sectors_per_fat), le32_to_cpu(b->bpb.large_sectors), b->bpb.fats); goto not_ntfs; } ntfs_log_debug("Checking clusters per mft record.\n"); if ((u8)b->clusters_per_mft_record < 0xe1 || (u8)b->clusters_per_mft_record > 0xf7) { switch (b->clusters_per_mft_record) { case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40: break; default: ntfs_log_error("Unexpected clusters per mft record " "(%d).\n", b->clusters_per_mft_record); goto not_ntfs; } } ntfs_log_debug("Checking clusters per index block.\n"); if ((u8)b->clusters_per_index_record < 0xe1 || (u8)b->clusters_per_index_record > 0xf7) { switch (b->clusters_per_index_record) { case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40: break; default: ntfs_log_error("Unexpected clusters per index record " "(%d).\n", b->clusters_per_index_record); goto not_ntfs; } } if (b->end_of_sector_marker != cpu_to_le16(0xaa55)) ntfs_log_debug("Warning: Bootsector has invalid end of sector " "marker.\n"); ntfs_log_debug("Bootsector check completed successfully.\n"); ret = TRUE; not_ntfs: return ret; } static const char *last_sector_error = "HINTS: Either the volume is a RAID/LDM but it wasn't setup yet,\n" " or it was not setup correctly (e.g. by not using mdadm --build ...),\n" " or a wrong device is tried to be mounted,\n" " or the partition table is corrupt (partition is smaller than NTFS),\n" " or the NTFS boot sector is corrupt (NTFS size is not valid).\n"; /** * ntfs_boot_sector_parse - setup an ntfs volume from an ntfs boot sector * @vol: ntfs_volume to setup * @bs: buffer containing ntfs boot sector to parse * * Parse the ntfs bootsector @bs and setup the ntfs volume @vol with the * obtained values. * * Return 0 on success or -1 on error with errno set to the error code EINVAL. */ int ntfs_boot_sector_parse(ntfs_volume *vol, const NTFS_BOOT_SECTOR *bs) { s64 sectors; u8 sectors_per_cluster; s8 c; /* We return -1 with errno = EINVAL on error. */ errno = EINVAL; vol->sector_size = le16_to_cpu(bs->bpb.bytes_per_sector); vol->sector_size_bits = ffs(vol->sector_size) - 1; ntfs_log_debug("SectorSize = 0x%x\n", vol->sector_size); ntfs_log_debug("SectorSizeBits = %u\n", vol->sector_size_bits); /* * The bounds checks on mft_lcn and mft_mirr_lcn (i.e. them being * below or equal the number_of_clusters) really belong in the * ntfs_boot_sector_is_ntfs but in this way we can just do this once. */ sectors_per_cluster = bs->bpb.sectors_per_cluster; ntfs_log_debug("SectorsPerCluster = 0x%x\n", sectors_per_cluster); if (sectors_per_cluster & (sectors_per_cluster - 1)) { ntfs_log_error("sectors_per_cluster (%d) is not a power of 2." "\n", sectors_per_cluster); return -1; } sectors = sle64_to_cpu(bs->number_of_sectors); ntfs_log_debug("NumberOfSectors = %l\n", (long long)sectors); if (!sectors) { ntfs_log_error("Volume size is set to zero.\n"); return -1; } if (vol->dev->d_ops->seek(vol->dev, (sectors - 1) << vol->sector_size_bits, SEEK_SET) == -1) { ntfs_log_perror("Failed to read last sector (%l)", (long long)sectors); ntfs_log_error("%s", last_sector_error); return -1; } vol->nr_clusters = sectors >> (ffs(sectors_per_cluster) - 1); vol->mft_lcn = sle64_to_cpu(bs->mft_lcn); vol->mftmirr_lcn = sle64_to_cpu(bs->mftmirr_lcn); ntfs_log_debug("MFT LCN = %l\n", (long long)vol->mft_lcn); ntfs_log_debug("MFTMirr LCN = %l\n", (long long)vol->mftmirr_lcn); if ((vol->mft_lcn < 0 || vol->mft_lcn > vol->nr_clusters) || (vol->mftmirr_lcn < 0 || vol->mftmirr_lcn > vol->nr_clusters)) { ntfs_log_error("$MFT LCN (%l) or $MFTMirr LCN (%l) is " "greater than the number of clusters (%l).\n", (long long)vol->mft_lcn, (long long)vol->mftmirr_lcn, (long long)vol->nr_clusters); return -1; } vol->cluster_size = sectors_per_cluster * vol->sector_size; if (vol->cluster_size & (vol->cluster_size - 1)) { ntfs_log_error("cluster_size (%d) is not a power of 2.\n", vol->cluster_size); return -1; } vol->cluster_size_bits = ffs(vol->cluster_size) - 1; /* * Need to get the clusters per mft record and handle it if it is * negative. Then calculate the mft_record_size. A value of 0x80 is * illegal, thus signed char is actually ok! */ c = bs->clusters_per_mft_record; ntfs_log_debug("ClusterSize = 0x%x\n", (unsigned)vol->cluster_size); ntfs_log_debug("ClusterSizeBits = %u\n", vol->cluster_size_bits); ntfs_log_debug("ClustersPerMftRecord = 0x%x\n", c); /* * When clusters_per_mft_record is negative, it means that it is to * be taken to be the negative base 2 logarithm of the mft_record_size * min bytes. Then: * mft_record_size = 2^(-clusters_per_mft_record) bytes. */ if (c < 0) vol->mft_record_size = 1 << -c; else vol->mft_record_size = c << vol->cluster_size_bits; if (vol->mft_record_size & (vol->mft_record_size - 1)) { ntfs_log_error("mft_record_size (%d) is not a power of 2.\n", vol->mft_record_size); return -1; } vol->mft_record_size_bits = ffs(vol->mft_record_size) - 1; ntfs_log_debug("MftRecordSize = 0x%x\n", (unsigned)vol->mft_record_size); ntfs_log_debug("MftRecordSizeBits = %u\n", vol->mft_record_size_bits); /* Same as above for INDX record. */ c = bs->clusters_per_index_record; ntfs_log_debug("ClustersPerINDXRecord = 0x%x\n", c); if (c < 0) vol->indx_record_size = 1 << -c; else vol->indx_record_size = c << vol->cluster_size_bits; vol->indx_record_size_bits = ffs(vol->indx_record_size) - 1; ntfs_log_debug("INDXRecordSize = 0x%x\n", (unsigned)vol->indx_record_size); ntfs_log_debug("INDXRecordSizeBits = %u\n", vol->indx_record_size_bits); /* * Work out the size of the MFT mirror in number of mft records. If the * cluster size is less than or equal to the size taken by four mft * records, the mft mirror stores the first four mft records. If the * cluster size is bigger than the size taken by four mft records, the * mft mirror contains as many mft records as will fit into one * cluster. */ if (vol->cluster_size <= 4 * vol->mft_record_size) vol->mftmirr_size = 4; else vol->mftmirr_size = vol->cluster_size / vol->mft_record_size; return 0; }