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-rw-r--r--libinstaller/fs.c172
1 files changed, 172 insertions, 0 deletions
diff --git a/libinstaller/fs.c b/libinstaller/fs.c
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--- /dev/null
+++ b/libinstaller/fs.c
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+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 1998-2011 H. Peter Anvin - All Rights Reserved
+ * Copyright 2009-2011 Intel Corporation; author H. Peter Anvin
+ * Copyright 2011 Paulo Alcantara <pcacjr@gmail.com>
+ *
+ * This program 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, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * fs.c - Generic sanity check for FAT/NTFS-based installers
+ */
+
+#define _XOPEN_SOURCE 500 /* Required on glibc 2.x */
+#define _BSD_SOURCE
+#include <stdio.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "syslinux.h"
+#include "syslxint.h"
+#include "syslxcom.h"
+#include "syslxfs.h"
+
+void syslinux_make_bootsect(void *bs, int fs_type)
+{
+ if (fs_type == VFAT) {
+ struct fat_boot_sector *bootsect = bs;
+ const struct fat_boot_sector *sbs =
+ (const struct fat_boot_sector *)boot_sector;
+
+ memcpy(&bootsect->FAT_bsHead, &sbs->FAT_bsHead, FAT_bsHeadLen);
+ memcpy(&bootsect->FAT_bsCode, &sbs->FAT_bsCode, FAT_bsCodeLen);
+ } else if (fs_type == NTFS) {
+ struct ntfs_boot_sector *bootsect = bs;
+ const struct ntfs_boot_sector *sbs =
+ (const struct ntfs_boot_sector *)boot_sector;
+
+ memcpy(&bootsect->NTFS_bsHead, &sbs->NTFS_bsHead, NTFS_bsHeadLen);
+ memcpy(&bootsect->NTFS_bsCode, &sbs->NTFS_bsCode, NTFS_bsCodeLen);
+ }
+}
+
+static const char *check_fat_bootsect(const void *bs, int *fs_type)
+{
+ int sectorsize;
+ const struct fat_boot_sector *sectbuf = bs;
+ long long sectors, fatsectors, dsectors;
+ long long clusters;
+ int rootdirents, clustersize;
+
+ sectorsize = get_16(&sectbuf->bsBytesPerSec);
+
+ clustersize = get_8(&sectbuf->bsSecPerClust);
+ if (clustersize == 0 || (clustersize & (clustersize - 1)))
+ return "impossible cluster size on an FAT volume";
+
+ sectors = get_16(&sectbuf->bsSectors);
+ sectors = sectors ? sectors : get_32(&sectbuf->bsHugeSectors);
+
+ dsectors = sectors - get_16(&sectbuf->bsResSectors);
+
+ fatsectors = get_16(&sectbuf->bsFATsecs);
+ fatsectors = fatsectors ? fatsectors : get_32(&sectbuf->bs32.FATSz32);
+ fatsectors *= get_8(&sectbuf->bsFATs);
+ dsectors -= fatsectors;
+
+ rootdirents = get_16(&sectbuf->bsRootDirEnts);
+ dsectors -= (rootdirents + sectorsize / 32 - 1) / sectorsize;
+
+ if (dsectors < 0)
+ return "negative number of data sectors on an FAT volume";
+
+ clusters = dsectors / clustersize;
+
+ fatsectors = get_16(&sectbuf->bsFATsecs);
+ fatsectors = fatsectors ? fatsectors : get_32(&sectbuf->bs32.FATSz32);
+ fatsectors *= get_8(&sectbuf->bsFATs);
+
+ if (!fatsectors)
+ return "zero FAT sectors";
+
+ if (clusters < 0xFFF5) {
+ /* FAT12 or FAT16 */
+ if (!get_16(&sectbuf->bsFATsecs))
+ return "zero FAT sectors (FAT12/16)";
+
+ if (get_8(&sectbuf->bs16.BootSignature) == 0x29) {
+ if (!memcmp(&sectbuf->bs16.FileSysType, "FAT12 ", 8)) {
+ if (clusters >= 0xFF5)
+ return "more than 4084 clusters but claims FAT12";
+ } else if (!memcmp(&sectbuf->bs16.FileSysType, "FAT16 ", 8)) {
+ if (clusters < 0xFF5)
+ return "less than 4084 clusters but claims FAT16";
+ } else if (!memcmp(&sectbuf->bs16.FileSysType, "FAT32 ", 8)) {
+ return "less than 65525 clusters but claims FAT32";
+ } else if (memcmp(&sectbuf->bs16.FileSysType, "FAT ", 8)) {
+ static char fserr[] = "filesystem type \"????????\" not "
+ "supported";
+ memcpy(fserr + 17, &sectbuf->bs16.FileSysType, 8);
+ return fserr;
+ }
+ }
+ } else if (clusters < 0x0FFFFFF5) {
+ /*
+ * FAT32...
+ *
+ * Moving the FileSysType and BootSignature was a lovely stroke
+ * of M$ idiocy...
+ */
+ if (get_8(&sectbuf->bs32.BootSignature) != 0x29 ||
+ memcmp(&sectbuf->bs32.FileSysType, "FAT32 ", 8))
+ return "missing FAT32 signature";
+ } else {
+ return "impossibly large number of clusters on an FAT volume";
+ }
+
+ if (fs_type)
+ *fs_type = VFAT;
+
+ return NULL;
+}
+
+static const char *check_ntfs_bootsect(const void *bs, int *fs_type)
+{
+ const struct ntfs_boot_sector *sectbuf = bs;
+
+ if (memcmp(&sectbuf->bsOemName, "NTFS ", 8) &&
+ memcmp(&sectbuf->bsOemName, "MSWIN4.0", 8) &&
+ memcmp(&sectbuf->bsOemName, "MSWIN4.1", 8))
+ return "unknown OEM name but claims NTFS";
+
+ if (fs_type)
+ *fs_type = NTFS;
+
+ return NULL;
+}
+
+const char *syslinux_check_bootsect(const void *bs, int *fs_type)
+{
+ uint8_t media_sig;
+ int sectorsize;
+ const struct fat_boot_sector *sectbuf = bs;
+ const char *retval;
+
+ media_sig = get_8(&sectbuf->bsMedia);
+ /* Must be 0xF0 or 0xF8-0xFF for FAT/NTFS volumes */
+ if (media_sig != 0xF0 && media_sig < 0xF8)
+ return "invalid media signature (not an FAT/NTFS volume?)";
+
+ sectorsize = get_16(&sectbuf->bsBytesPerSec);
+ if (sectorsize == SECTOR_SIZE) ; /* ok */
+ else if (sectorsize >= 512 && sectorsize <= 4096 &&
+ (sectorsize & (sectorsize - 1)) == 0)
+ return "unsupported sectors size";
+ else
+ return "impossible sector size";
+
+ if (ntfs_check_zero_fields((struct ntfs_boot_sector *)bs))
+ retval = check_ntfs_bootsect(bs, fs_type);
+ else
+ retval = check_fat_bootsect(bs, fs_type);
+
+ return retval;
+}