1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 1998-2011 H. Peter Anvin - All Rights Reserved 4 * Copyright 2009-2011 Intel Corporation; author H. Peter Anvin 5 * Copyright 2011 Paulo Alcantara <pcacjr (at) gmail.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation, Inc., 53 Temple Place Ste 330, 10 * Boston MA 02111-1307, USA; either version 2 of the License, or 11 * (at your option) any later version; incorporated herein by reference. 12 * 13 * ----------------------------------------------------------------------- */ 14 15 /* 16 * fs.c - Generic sanity check for FAT/NTFS-based installers 17 */ 18 19 #define _XOPEN_SOURCE 500 /* Required on glibc 2.x */ 20 #define _BSD_SOURCE 21 /* glibc 2.20 deprecates _BSD_SOURCE in favour of _DEFAULT_SOURCE */ 22 #define _DEFAULT_SOURCE 1 23 #include <stdio.h> 24 #include <inttypes.h> 25 #include <string.h> 26 #include <stddef.h> 27 #include <stdlib.h> 28 29 #include "syslinux.h" 30 #include "syslxint.h" 31 #include "syslxcom.h" 32 #include "syslxfs.h" 33 34 void syslinux_make_bootsect(void *bs, int fs_type) 35 { 36 if (fs_type == VFAT) { 37 struct fat_boot_sector *bootsect = bs; 38 const struct fat_boot_sector *sbs = 39 (const struct fat_boot_sector *)boot_sector; 40 41 memcpy(&bootsect->FAT_bsHead, &sbs->FAT_bsHead, FAT_bsHeadLen); 42 memcpy(&bootsect->FAT_bsCode, &sbs->FAT_bsCode, FAT_bsCodeLen); 43 } else if (fs_type == NTFS) { 44 struct ntfs_boot_sector *bootsect = bs; 45 const struct ntfs_boot_sector *sbs = 46 (const struct ntfs_boot_sector *)boot_sector; 47 48 memcpy(&bootsect->NTFS_bsHead, &sbs->NTFS_bsHead, NTFS_bsHeadLen); 49 memcpy(&bootsect->NTFS_bsCode, &sbs->NTFS_bsCode, NTFS_bsCodeLen); 50 } 51 } 52 53 static const char *check_fat_bootsect(const void *bs, int *fs_type) 54 { 55 int sectorsize; 56 const struct fat_boot_sector *sectbuf = bs; 57 long long sectors, fatsectors, dsectors; 58 long long clusters; 59 int rootdirents, clustersize; 60 61 sectorsize = get_16(§buf->bsBytesPerSec); 62 63 clustersize = get_8(§buf->bsSecPerClust); 64 if (clustersize == 0 || (clustersize & (clustersize - 1))) 65 return "impossible cluster size on an FAT volume"; 66 67 sectors = get_16(§buf->bsSectors); 68 sectors = sectors ? sectors : get_32(§buf->bsHugeSectors); 69 70 dsectors = sectors - get_16(§buf->bsResSectors); 71 72 fatsectors = get_16(§buf->bsFATsecs); 73 fatsectors = fatsectors ? fatsectors : get_32(§buf->bs32.FATSz32); 74 fatsectors *= get_8(§buf->bsFATs); 75 dsectors -= fatsectors; 76 77 rootdirents = get_16(§buf->bsRootDirEnts); 78 dsectors -= (rootdirents + sectorsize / 32 - 1) / sectorsize; 79 80 if (dsectors < 0) 81 return "negative number of data sectors on an FAT volume"; 82 83 clusters = dsectors / clustersize; 84 85 fatsectors = get_16(§buf->bsFATsecs); 86 fatsectors = fatsectors ? fatsectors : get_32(§buf->bs32.FATSz32); 87 fatsectors *= get_8(§buf->bsFATs); 88 89 if (!fatsectors) 90 return "zero FAT sectors"; 91 92 if (clusters < 0xFFF5) { 93 /* FAT12 or FAT16 */ 94 if (!get_16(§buf->bsFATsecs)) 95 return "zero FAT sectors (FAT12/16)"; 96 97 if (get_8(§buf->bs16.BootSignature) == 0x29) { 98 if (!memcmp(§buf->bs16.FileSysType, "FAT12 ", 8)) { 99 if (clusters >= 0xFF5) 100 return "more than 4084 clusters but claims FAT12"; 101 } else if (!memcmp(§buf->bs16.FileSysType, "FAT16 ", 8)) { 102 if (clusters < 0xFF5) 103 return "less than 4084 clusters but claims FAT16"; 104 } else if (!memcmp(§buf->bs16.FileSysType, "FAT32 ", 8)) { 105 return "less than 65525 clusters but claims FAT32"; 106 } else if (memcmp(§buf->bs16.FileSysType, "FAT ", 8)) { 107 static char fserr[] = "filesystem type \"????????\" not " 108 "supported"; 109 memcpy(fserr + 17, §buf->bs16.FileSysType, 8); 110 return fserr; 111 } 112 } 113 } else if (clusters < 0x0FFFFFF5) { 114 /* 115 * FAT32... 116 * 117 * Moving the FileSysType and BootSignature was a lovely stroke 118 * of M$ idiocy... 119 */ 120 if (get_8(§buf->bs32.BootSignature) != 0x29 || 121 memcmp(§buf->bs32.FileSysType, "FAT32 ", 8)) 122 return "missing FAT32 signature"; 123 } else { 124 return "impossibly large number of clusters on an FAT volume"; 125 } 126 127 if (fs_type) 128 *fs_type = VFAT; 129 130 return NULL; 131 } 132 133 static const char *check_ntfs_bootsect(const void *bs, int *fs_type) 134 { 135 const struct ntfs_boot_sector *sectbuf = bs; 136 137 if (memcmp(§buf->bsOemName, "NTFS ", 8) && 138 memcmp(§buf->bsOemName, "MSWIN4.0", 8) && 139 memcmp(§buf->bsOemName, "MSWIN4.1", 8)) 140 return "unknown OEM name but claims NTFS"; 141 142 if (fs_type) 143 *fs_type = NTFS; 144 145 return NULL; 146 } 147 148 const char *syslinux_check_bootsect(const void *bs, int *fs_type) 149 { 150 uint8_t media_sig; 151 int sectorsize; 152 const struct fat_boot_sector *sectbuf = bs; 153 const char *retval; 154 155 media_sig = get_8(§buf->bsMedia); 156 /* Must be 0xF0 or 0xF8-0xFF for FAT/NTFS volumes */ 157 if (media_sig != 0xF0 && media_sig < 0xF8) 158 return "invalid media signature (not an FAT/NTFS volume?)"; 159 160 sectorsize = get_16(§buf->bsBytesPerSec); 161 if (sectorsize == SECTOR_SIZE) ; /* ok */ 162 else if (sectorsize >= 512 && sectorsize <= 4096 && 163 (sectorsize & (sectorsize - 1)) == 0) 164 return "unsupported sectors size"; 165 else 166 return "impossible sector size"; 167 168 if (ntfs_check_zero_fields((struct ntfs_boot_sector *)bs)) 169 retval = check_ntfs_bootsect(bs, fs_type); 170 else 171 retval = check_fat_bootsect(bs, fs_type); 172 173 return retval; 174 } 175
