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|
/*
** fatxxfs
** The Sleuth Kit
**
** Content and meta data layer support for the FATXX file system
**
** Brian Carrier [carrier <at> sleuthkit [dot] org]
** Copyright (c) 2006-2013 Brian Carrier, Basis Technology. All Rights reserved
** Copyright (c) 2003-2005 Brian Carrier. All rights reserved
**
** TASK
** Copyright (c) 2002 Brian Carrier, @stake Inc. All rights reserved
**
**
** This software is distributed under the Common Public License 1.0
**
** Unicode added with support from I.D.E.A.L. Technology Corp (Aug '05)
**
*/
/**
* \file fatxxfs.c
* Contains the internal TSK FATXX (FAT12, FAT16, FAT32) file system code to
* handle basic file system processing for opening file system, processing
* sectors, and directory entries.
*/
#include "tsk_fatxxfs.h"
/*
* Implementation NOTES
*
* TSK_FS_META contains the first cluster. file_walk will return sector
* values though because the cluster numbers do not start until after
* the FAT. That makes it very hard to address the first few blocks!
*
* Inodes numbers do not exist in FAT. To make up for this we will count
* directory entries as the inodes. As the root directory does not have
* any records in FAT, we will give it times of 0 and call it inode 2 to
* keep consistent with UNIX. After that, each 32-byte slot is numbered
* as though it were a directory entry (even if it is not). Therefore,
* when an inode walk is performed, not all inode values will be displayed
* even when '-e' is given for ils.
*
* Progs like 'ils -e' are very slow because we have to look at each
* block to see if it is a file system structure.
*/
/**
* Print details about the file system to a file handle.
*
* @param fs File system to print details on
* @param hFile File handle to print text to
*
* @returns 1 on error and 0 on success
*/
static uint8_t
fatxxfs_fsstat(TSK_FS_INFO * fs, FILE * hFile)
{
unsigned int i;
TSK_DADDR_T next, snext, sstart, send;
FATFS_INFO *fatfs = (FATFS_INFO *) fs;
FATXXFS_SB *sb = (FATXXFS_SB*)fatfs->boot_sector_buffer;
char *data_buf;
FATXXFS_DENTRY *vol_label_dentry = NULL;
ssize_t cnt;
// clean up any error messages that are lying around
tsk_error_reset();
if ((data_buf = (char *) tsk_malloc(fs->block_size)) == NULL) {
return 1;
}
/* Read the root directory sector so that we can get the volume
* label from it */
cnt = tsk_fs_read_block(fs, fatfs->rootsect, data_buf, fs->block_size);
if (cnt != fs->block_size) {
if (cnt >= 0) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_READ);
}
tsk_error_set_errstr2("fatxxfs_fsstat: root directory: %" PRIuDADDR,
fatfs->rootsect);
free(data_buf);
return 1;
}
/* Find the dentry that is set as the volume label */
vol_label_dentry = NULL;
if (fatfs->ssize <= fs->block_size) {
FATXXFS_DENTRY *current_entry = (FATXXFS_DENTRY *) data_buf;
for (i = 0; i < fatfs->ssize; i += sizeof(*current_entry)) {
if (current_entry->attrib == FATFS_ATTR_VOLUME) {
vol_label_dentry = current_entry;
break;
}
current_entry++;
}
}
/* Print the general file system information */
tsk_fprintf(hFile, "FILE SYSTEM INFORMATION\n");
tsk_fprintf(hFile, "--------------------------------------------\n");
tsk_fprintf(hFile, "File System Type: FAT");
if (fs->ftype == TSK_FS_TYPE_FAT12)
tsk_fprintf(hFile, "12\n");
else if (fs->ftype == TSK_FS_TYPE_FAT16)
tsk_fprintf(hFile, "16\n");
else if (fs->ftype == TSK_FS_TYPE_FAT32)
tsk_fprintf(hFile, "32\n");
else
tsk_fprintf(hFile, "\n");
tsk_fprintf(hFile, "\nOEM Name: %c%c%c%c%c%c%c%c\n", sb->oemname[0],
sb->oemname[1], sb->oemname[2], sb->oemname[3], sb->oemname[4],
sb->oemname[5], sb->oemname[6], sb->oemname[7]);
if (fatfs->fs_info.ftype != TSK_FS_TYPE_FAT32) {
tsk_fprintf(hFile, "Volume ID: 0x%" PRIx32 "\n",
tsk_getu32(fs->endian, sb->a.f16.vol_id));
tsk_fprintf(hFile,
"Volume Label (Boot Sector): %c%c%c%c%c%c%c%c%c%c%c\n",
sb->a.f16.vol_lab[0], sb->a.f16.vol_lab[1],
sb->a.f16.vol_lab[2], sb->a.f16.vol_lab[3],
sb->a.f16.vol_lab[4], sb->a.f16.vol_lab[5],
sb->a.f16.vol_lab[6], sb->a.f16.vol_lab[7],
sb->a.f16.vol_lab[8], sb->a.f16.vol_lab[9],
sb->a.f16.vol_lab[10]);
if ((vol_label_dentry) && (vol_label_dentry->name[0])) {
tsk_fprintf(hFile,
"Volume Label (Root Directory): %c%c%c%c%c%c%c%c%c%c%c\n",
vol_label_dentry->name[0], vol_label_dentry->name[1], vol_label_dentry->name[2], vol_label_dentry->name[3],
vol_label_dentry->name[4], vol_label_dentry->name[5], vol_label_dentry->name[6], vol_label_dentry->name[7],
vol_label_dentry->ext[0], vol_label_dentry->ext[1], vol_label_dentry->ext[2]);
}
else {
tsk_fprintf(hFile, "Volume Label (Root Directory):\n");
}
tsk_fprintf(hFile, "File System Type Label: %c%c%c%c%c%c%c%c\n",
sb->a.f16.fs_type[0], sb->a.f16.fs_type[1],
sb->a.f16.fs_type[2], sb->a.f16.fs_type[3],
sb->a.f16.fs_type[4], sb->a.f16.fs_type[5],
sb->a.f16.fs_type[6], sb->a.f16.fs_type[7]);
}
else {
char *fat_fsinfo_buf;
if ((fat_fsinfo_buf = (char *)
tsk_malloc(sizeof(FATXXFS_FSINFO))) == NULL) {
free(data_buf);
return 1;
}
tsk_fprintf(hFile, "Volume ID: 0x%" PRIx32 "\n",
tsk_getu32(fs->endian, sb->a.f32.vol_id));
tsk_fprintf(hFile,
"Volume Label (Boot Sector): %c%c%c%c%c%c%c%c%c%c%c\n",
sb->a.f32.vol_lab[0], sb->a.f32.vol_lab[1],
sb->a.f32.vol_lab[2], sb->a.f32.vol_lab[3],
sb->a.f32.vol_lab[4], sb->a.f32.vol_lab[5],
sb->a.f32.vol_lab[6], sb->a.f32.vol_lab[7],
sb->a.f32.vol_lab[8], sb->a.f32.vol_lab[9],
sb->a.f32.vol_lab[10]);
if ((vol_label_dentry) && (vol_label_dentry->name[0])) {
tsk_fprintf(hFile,
"Volume Label (Root Directory): %c%c%c%c%c%c%c%c%c%c%c\n",
vol_label_dentry->name[0], vol_label_dentry->name[1], vol_label_dentry->name[2], vol_label_dentry->name[3],
vol_label_dentry->name[4], vol_label_dentry->name[5], vol_label_dentry->name[6], vol_label_dentry->name[7],
vol_label_dentry->ext[0], vol_label_dentry->ext[1], vol_label_dentry->ext[2]);
}
else {
tsk_fprintf(hFile, "Volume Label (Root Directory):\n");
}
tsk_fprintf(hFile, "File System Type Label: %c%c%c%c%c%c%c%c\n",
sb->a.f32.fs_type[0], sb->a.f32.fs_type[1],
sb->a.f32.fs_type[2], sb->a.f32.fs_type[3],
sb->a.f32.fs_type[4], sb->a.f32.fs_type[5],
sb->a.f32.fs_type[6], sb->a.f32.fs_type[7]);
/* Process the FS info */
if (tsk_getu16(fs->endian, sb->a.f32.fsinfo)) {
FATXXFS_FSINFO *fat_info;
cnt =
tsk_fs_read(fs,
(TSK_DADDR_T) tsk_getu16(fs->endian, sb->a.f32.fsinfo) * fs->block_size,
fat_fsinfo_buf, sizeof(FATXXFS_FSINFO));
if (cnt != sizeof(FATXXFS_FSINFO)) {
if (cnt >= 0) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_READ);
}
tsk_error_set_errstr2
("fatxxfs_fsstat: TSK_FS_TYPE_FAT32 FSINFO block: %"
PRIuDADDR, (TSK_DADDR_T) tsk_getu16(fs->endian,
sb->a.f32.fsinfo));
free(data_buf);
free(fat_fsinfo_buf);
return 1;
}
fat_info = (FATXXFS_FSINFO *) fat_fsinfo_buf;
tsk_fprintf(hFile,
"Next Free Sector (FS Info): %" PRIuDADDR "\n",
FATFS_CLUST_2_SECT(fatfs, tsk_getu32(fs->endian,
fat_info->nextfree)));
tsk_fprintf(hFile,
"Free Sector Count (FS Info): %" PRIu32 "\n",
(tsk_getu32(fs->endian,
fat_info->freecnt) * fatfs->csize));
free(fat_fsinfo_buf);
}
}
free(data_buf);
tsk_fprintf(hFile, "\nSectors before file system: %" PRIu32 "\n",
tsk_getu32(fs->endian, sb->prevsect));
tsk_fprintf(hFile, "\nFile System Layout (in sectors)\n");
tsk_fprintf(hFile, "Total Range: %" PRIuDADDR " - %" PRIuDADDR "\n",
fs->first_block, fs->last_block);
if (fs->last_block != fs->last_block_act)
tsk_fprintf(hFile,
"Total Range in Image: %" PRIuDADDR " - %" PRIuDADDR "\n",
fs->first_block, fs->last_block_act);
tsk_fprintf(hFile, "* Reserved: 0 - %" PRIuDADDR "\n",
fatfs->firstfatsect - 1);
tsk_fprintf(hFile, "** Boot Sector: 0\n");
if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT32) {
tsk_fprintf(hFile, "** FS Info Sector: %" PRIu16 "\n",
tsk_getu16(fs->endian, sb->a.f32.fsinfo));
tsk_fprintf(hFile, "** Backup Boot Sector: %" PRIu16 "\n",
tsk_getu16(fs->endian, sb->a.f32.bs_backup));
}
for (i = 0; i < fatfs->numfat; i++) {
TSK_DADDR_T base = fatfs->firstfatsect + i * (fatfs->sectperfat);
tsk_fprintf(hFile, "* FAT %d: %" PRIuDADDR " - %" PRIuDADDR "\n",
i, base, (base + fatfs->sectperfat - 1));
}
tsk_fprintf(hFile, "* Data Area: %" PRIuDADDR " - %" PRIuDADDR "\n",
fatfs->firstdatasect, fs->last_block);
if (fatfs->fs_info.ftype != TSK_FS_TYPE_FAT32) {
TSK_DADDR_T x = fatfs->csize * fatfs->clustcnt;
tsk_fprintf(hFile,
"** Root Directory: %" PRIuDADDR " - %" PRIuDADDR "\n",
fatfs->firstdatasect, fatfs->firstclustsect - 1);
tsk_fprintf(hFile,
"** Cluster Area: %" PRIuDADDR " - %" PRIuDADDR "\n",
fatfs->firstclustsect, (fatfs->firstclustsect + x - 1));
if ((fatfs->firstclustsect + x - 1) != fs->last_block) {
tsk_fprintf(hFile,
"** Non-clustered: %" PRIuDADDR " - %" PRIuDADDR "\n",
(fatfs->firstclustsect + x), fs->last_block);
}
}
else {
TSK_LIST *list_seen = NULL;
TSK_DADDR_T x = fatfs->csize * (fatfs->lastclust - 1);
TSK_DADDR_T clust, clust_p;
tsk_fprintf(hFile,
"** Cluster Area: %" PRIuDADDR " - %" PRIuDADDR "\n",
fatfs->firstclustsect, (fatfs->firstclustsect + x - 1));
clust_p = fatfs->rootsect;
clust = FATFS_SECT_2_CLUST(fatfs, fatfs->rootsect);
while ((clust) && (0 == FATFS_ISEOF(clust, FATFS_32_MASK))) {
TSK_DADDR_T nxt;
clust_p = clust;
/* Make sure we do not get into an infinite loop */
if (tsk_list_find(list_seen, clust)) {
if (tsk_verbose)
tsk_fprintf(stderr,
"Loop found while determining root directory size\n");
break;
}
if (tsk_list_add(&list_seen, clust)) {
tsk_list_free(list_seen);
list_seen = NULL;
return 1;
}
if (fatfs_getFAT(fatfs, clust, &nxt))
break;
clust = nxt;
}
tsk_list_free(list_seen);
list_seen = NULL;
tsk_fprintf(hFile,
"*** Root Directory: %" PRIuDADDR " - %" PRIuDADDR "\n",
fatfs->rootsect, (FATFS_CLUST_2_SECT(fatfs, clust_p + 1) - 1));
if ((fatfs->firstclustsect + x - 1) != fs->last_block) {
tsk_fprintf(hFile,
"** Non-clustered: %" PRIuDADDR " - %" PRIuDADDR "\n",
(fatfs->firstclustsect + x), fs->last_block);
}
}
tsk_fprintf(hFile, "\nMETADATA INFORMATION\n");
tsk_fprintf(hFile, "--------------------------------------------\n");
tsk_fprintf(hFile, "Range: %" PRIuINUM " - %" PRIuINUM "\n",
fs->first_inum, fs->last_inum);
tsk_fprintf(hFile, "Root Directory: %" PRIuINUM "\n", fs->root_inum);
tsk_fprintf(hFile, "\nCONTENT INFORMATION\n");
tsk_fprintf(hFile, "--------------------------------------------\n");
tsk_fprintf(hFile, "Sector Size: %" PRIu16 "\n", fatfs->ssize);
tsk_fprintf(hFile, "Cluster Size: %" PRIu32 "\n",
(uint32_t) fatfs->csize << fatfs->ssize_sh);
tsk_fprintf(hFile, "Total Cluster Range: 2 - %" PRIuDADDR "\n",
fatfs->lastclust);
/* cycle via cluster and look at each cluster in the FAT
* for clusters marked as bad */
cnt = 0;
for (i = 2; i <= fatfs->lastclust; i++) {
TSK_DADDR_T entry;
TSK_DADDR_T sect;
unsigned int a;
/* Get the FAT table entry */
if (fatfs_getFAT(fatfs, i, &entry))
break;
if (FATFS_ISBAD(entry, fatfs->mask) == 0) {
continue;
}
if (cnt == 0)
tsk_fprintf(hFile, "Bad Sectors: ");
sect = FATFS_CLUST_2_SECT(fatfs, i);
for (a = 0; a < fatfs->csize; a++) {
tsk_fprintf(hFile, "%" PRIuDADDR " ", sect + a);
if ((++cnt % 8) == 0)
tsk_fprintf(hFile, "\n");
}
}
if ((cnt > 0) && ((cnt % 8) != 0))
tsk_fprintf(hFile, "\n");
/* Display the FAT Table */
tsk_fprintf(hFile, "\nFAT CONTENTS (in sectors)\n");
tsk_fprintf(hFile, "--------------------------------------------\n");
/* 'sstart' marks the first sector of the current run to print */
sstart = fatfs->firstclustsect;
/* cycle via cluster and look at each cluster in the FAT to make runs */
for (i = 2; i <= fatfs->lastclust; i++) {
/* 'send' marks the end sector of the current run, which will extend
* when the current cluster continues to the next
*/
send = FATFS_CLUST_2_SECT(fatfs, i + 1) - 1;
/* get the next cluster */
if (fatfs_getFAT(fatfs, i, &next))
break;
snext = FATFS_CLUST_2_SECT(fatfs, next);
/* we are also using the next sector (clust) */
if ((next & fatfs->mask) == (i + 1)) {
continue;
}
/* The next clust is either further away or the clust is available,
* print it if is further away
*/
else if ((next & fatfs->mask)) {
if (FATFS_ISEOF(next, fatfs->mask))
tsk_fprintf(hFile,
"%" PRIuDADDR "-%" PRIuDADDR " (%" PRIuDADDR
") -> EOF\n", sstart, send, send - sstart + 1);
else if (FATFS_ISBAD(next, fatfs->mask))
tsk_fprintf(hFile,
"%" PRIuDADDR "-%" PRIuDADDR " (%" PRIuDADDR
") -> BAD\n", sstart, send, send - sstart + 1);
else
tsk_fprintf(hFile,
"%" PRIuDADDR "-%" PRIuDADDR " (%" PRIuDADDR
") -> %" PRIuDADDR "\n", sstart, send,
send - sstart + 1, snext);
}
/* reset the starting counter */
sstart = send + 1;
}
return 0;
}
uint8_t
fatxxfs_open(FATFS_INFO *fatfs)
{
const char *func_name = "fatxxfs_open";
TSK_FS_INFO *fs = &(fatfs->fs_info);
FATXXFS_SB *fatsb = (FATXXFS_SB*)(&fatfs->boot_sector_buffer);
int i = 0;
TSK_DADDR_T sectors = 0;
TSK_FS_DIR * test_dir1; // Directories used to try opening the root directory
// clean up any error messages that are lying around
tsk_error_reset();
/* Calculate block sizes and layout info */
// sector size
fatfs->ssize = tsk_getu16(fs->endian, fatsb->ssize);
if (fatfs->ssize == 512) {
fatfs->ssize_sh = 9;
}
else if (fatfs->ssize == 1024) {
fatfs->ssize_sh = 10;
}
else if (fatfs->ssize == 2048) {
fatfs->ssize_sh = 11;
}
else if (fatfs->ssize == 4096) {
fatfs->ssize_sh = 12;
}
else {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Error: sector size (%d) is not a multiple of device size (%d)\nDo you have a disk image instead of a partition image?",
fatfs->ssize, fs->dev_bsize);
if (tsk_verbose)
fprintf(stderr, "%s: Invalid sector size (%d)\n",
func_name, fatfs->ssize);
return 1;
}
// cluster size
fatfs->csize = fatsb->csize;
if ((fatfs->csize != 0x01) &&
(fatfs->csize != 0x02) &&
(fatfs->csize != 0x04) &&
(fatfs->csize != 0x08) &&
(fatfs->csize != 0x10) &&
(fatfs->csize != 0x20) &&
(fatfs->csize != 0x40) && (fatfs->csize != 0x80)) {
if (tsk_verbose)
fprintf(stderr, "%s: Invalid cluster size (%d)\n",
func_name, fatfs->csize);
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr("Not a FATXX file system (cluster size)");
return 1;
}
// number of FAT tables
fatfs->numfat = fatsb->numfat;
if ((fatfs->numfat == 0) || (fatfs->numfat > 8)) {
if (tsk_verbose)
fprintf(stderr, "%s: Invalid number of FATS (%d)\n",
func_name, fatfs->numfat);
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr("Not a FATXX file system (number of FATs)");
return 1;
}
/* We can't do a sanity check on this b.c. TSK_FS_TYPE_FAT32 has a value of 0 */
/* num of root entries */
fatfs->numroot = tsk_getu16(fs->endian, fatsb->numroot);
/* if sectors16 is 0, then the number of sectors is stored in sectors32 */
if (0 == (sectors = tsk_getu16(fs->endian, fatsb->sectors16)))
sectors = tsk_getu32(fs->endian, fatsb->sectors32);
/* if secperfat16 is 0, then read sectperfat32 */
if (0 == (fatfs->sectperfat =
tsk_getu16(fs->endian, fatsb->sectperfat16)))
fatfs->sectperfat =
tsk_getu32(fs->endian, fatsb->a.f32.sectperfat32);
if (fatfs->sectperfat == 0) {
if (tsk_verbose)
fprintf(stderr,
"%s: Invalid number of sectors per FAT (%d)\n",
func_name, fatfs->sectperfat);
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Not a FATXX file system (invalid sectors per FAT)");
return 1;
}
fatfs->firstfatsect = tsk_getu16(fs->endian, fatsb->reserved);
if ((fatfs->firstfatsect == 0) || (fatfs->firstfatsect > sectors)) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_WALK_RNG);
tsk_error_set_errstr
("Not a FATXX file system (invalid first FAT sector %"
PRIuDADDR ")", fatfs->firstfatsect);
if (tsk_verbose)
fprintf(stderr,
"%s: Invalid first FAT (%" PRIuDADDR ")\n",
func_name, fatfs->firstfatsect);
return 1;
}
/* Calculate the block info
*
* The sector of the beginning of the data area - which is
* after all of the FATs
*
* For TSK_FS_TYPE_FAT12 and TSK_FS_TYPE_FAT16, the data area starts with the root
* directory entries and then the first cluster. For TSK_FS_TYPE_FAT32,
* the data area starts with clusters and the root directory
* is somewhere in the data area
*/
fatfs->firstdatasect = fatfs->firstfatsect +
fatfs->sectperfat * fatfs->numfat;
/* The sector where the first cluster is located. It will be used
* to translate cluster addresses to sector addresses
*
* For TSK_FS_TYPE_FAT32, the first cluster is the start of the data area and
* it is after the root directory for TSK_FS_TYPE_FAT12 and TSK_FS_TYPE_FAT16. At this
* point in the program, numroot is set to 0 for TSK_FS_TYPE_FAT32
*/
fatfs->firstclustsect = fatfs->firstdatasect +
((fatfs->numroot * 32 + fatfs->ssize - 1) / fatfs->ssize);
/* total number of clusters */
fatfs->clustcnt = (sectors - fatfs->firstclustsect) / fatfs->csize;
/* the first cluster is #2, so the final cluster is: */
fatfs->lastclust = 1 + fatfs->clustcnt;
/* identify the FAT type by the total number of data clusters
* this calculation is from the MS FAT Overview Doc
*
* A FAT file system made by another OS could use different values
*/
if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT_DETECT) {
if (fatfs->clustcnt < 4085) {
fatfs->fs_info.ftype = TSK_FS_TYPE_FAT12;
}
else if (fatfs->clustcnt < 65525) {
fatfs->fs_info.ftype = TSK_FS_TYPE_FAT16;
}
else {
fatfs->fs_info.ftype = TSK_FS_TYPE_FAT32;
}
fatfs->fs_info.ftype = fatfs->fs_info.ftype;
}
/* Some sanity checks */
else {
if ((fatfs->fs_info.ftype == TSK_FS_TYPE_FAT12)
&& (fatfs->clustcnt >= 4085)) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Too many sectors for TSK_FS_TYPE_FAT12: try auto-detect mode");
if (tsk_verbose)
fprintf(stderr,
"%s: Too many sectors for FAT12\n", func_name);
return 1;
}
}
if ((fatfs->fs_info.ftype == TSK_FS_TYPE_FAT32) && (fatfs->numroot != 0)) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Invalid TSK_FS_TYPE_FAT32 image (numroot != 0)");
if (tsk_verbose)
fprintf(stderr, "%s: numroom != 0 for FAT32\n", func_name);
return 1;
}
if ((fatfs->fs_info.ftype != TSK_FS_TYPE_FAT32) && (fatfs->numroot == 0)) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Invalid FAT image (numroot == 0, and not TSK_FS_TYPE_FAT32)");
if (tsk_verbose)
fprintf(stderr, "%s: numroom == 0 and not FAT32\n", func_name);
return 1;
}
/* additional sanity checks if we think we are using the backup boot sector.
* The scenario to prevent here is if fat_open is called 6 sectors before the real start
* of the file system, then we want to detect that it was not a backup that we saw.
*/
if (fatfs->using_backup_boot_sector) {
// only FAT32 has backup boot sectors..
if (fatfs->fs_info.ftype != TSK_FS_TYPE_FAT32) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Invalid FAT image (Used what we thought was a backup boot sector, but it is not TSK_FS_TYPE_FAT32)");
if (tsk_verbose)
fprintf(stderr,
"%s: Had to use backup boot sector, but this isn't FAT32\n", func_name);
return 1;
}
if (fatfs->numroot > 1) {
uint8_t buf1[512];
uint8_t buf2[512];
int i2;
int numDiffs;
ssize_t cnt = 0;
cnt =
tsk_fs_read(fs, fatfs->firstfatsect * fatfs->ssize,
(char *) buf1, 512);
if (cnt != 512) {
if (cnt >= 0) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_READ);
}
tsk_error_set_errstr2("%s: FAT1", func_name);
fs->tag = 0;
return 1;
}
cnt =
tsk_fs_read(fs,
(fatfs->firstfatsect + fatfs->sectperfat) * fatfs->ssize,
(char *) buf2, 512);
if (cnt != 512) {
if (cnt >= 0) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_READ);
}
tsk_error_set_errstr2("%s: FAT2", func_name);
fs->tag = 0;
return 1;
}
numDiffs = 0;
for (i2 = 0; i2 < 512; i2++) {
if (buf1[i2] != buf2[i2]) {
numDiffs++;
}
}
if (numDiffs > 25) {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_MAGIC);
tsk_error_set_errstr
("Invalid FAT image (Too many differences between FATS from guessing (%d diffs))",
numDiffs);
if (tsk_verbose)
fprintf(stderr,
"%s: Too many differences in FAT from guessing (%d diffs)\n",
func_name, numDiffs);
return 1;
}
}
}
/* Set the mask to use on the cluster values */
if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT12) {
fatfs->mask = FATFS_12_MASK;
}
else if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT16) {
fatfs->mask = FATFS_16_MASK;
}
else if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT32) {
fatfs->mask = FATFS_32_MASK;
}
else {
tsk_error_reset();
tsk_error_set_errno(TSK_ERR_FS_ARG);
tsk_error_set_errstr("Unknown FAT type in %s: %d\n",
func_name, fatfs->fs_info.ftype);
return 1;
}
fs->duname = "Sector";
/* the root directories are always after the FAT for TSK_FS_TYPE_FAT12 and TSK_FS_TYPE_FAT16,
* but are dynamically located for TSK_FS_TYPE_FAT32
*/
if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT32)
fatfs->rootsect = FATFS_CLUST_2_SECT(fatfs,
tsk_getu32(fs->endian, fatsb->a.f32.rootclust));
else
fatfs->rootsect = fatfs->firstdatasect;
for (i = 0; i < FATFS_FAT_CACHE_N; i++) {
fatfs->fatc_addr[i] = 0;
fatfs->fatc_ttl[i] = 0;
}
/*
* block calculations : although there are no blocks in fat, we will
* use these fields for sector calculations
*/
fs->first_block = 0;
fs->block_count = sectors;
fs->last_block = fs->last_block_act = fs->block_count - 1;
fs->block_size = fatfs->ssize;
// determine the last block we have in this image
if ((TSK_DADDR_T) ((fatfs->fs_info.img_info->size - fatfs->fs_info.offset) / fs->block_size) <
fs->block_count)
fs->last_block_act =
(fatfs->fs_info.img_info->size - fatfs->fs_info.offset) / fs->block_size - 1;
/*
* inode calculations
*/
/* maximum number of dentries in a sector & cluster */
fatfs->dentry_cnt_se = fatfs->ssize / sizeof(FATXXFS_DENTRY);
fatfs->dentry_cnt_cl = fatfs->dentry_cnt_se * fatfs->csize;
fs->root_inum = FATFS_ROOTINO;
fs->first_inum = FATFS_FIRSTINO;
/* Calculate inode addresses for the virtual files (MBR, one or two FATS)
* and the virtual orphan files directory. */
fs->last_inum = (FATFS_SECT_2_INODE(fatfs, fs->last_block_act + 1) - 1) + FATFS_NUM_VIRT_FILES(fatfs);
fatfs->mbr_virt_inum = fs->last_inum - FATFS_NUM_VIRT_FILES(fatfs) + 1;
fatfs->fat1_virt_inum = fatfs->mbr_virt_inum + 1;
if (fatfs->numfat == 2) {
fatfs->fat2_virt_inum = fatfs->fat1_virt_inum + 1;
}
else {
fatfs->fat2_virt_inum = fatfs->fat1_virt_inum;
}
/* Calculate the total number of inodes. */
fs->inum_count = fs->last_inum - fs->first_inum + 1;
/* Volume ID */
for (fs->fs_id_used = 0; fs->fs_id_used < 4; fs->fs_id_used++) {
if (fatfs->fs_info.ftype == TSK_FS_TYPE_FAT32)
fs->fs_id[fs->fs_id_used] =
fatsb->a.f32.vol_id[fs->fs_id_used];
else
fs->fs_id[fs->fs_id_used] =
fatsb->a.f16.vol_id[fs->fs_id_used];
}
/*
* Set the function pointers
*/
fs->block_walk = fatfs_block_walk;
fs->block_getflags = fatfs_block_getflags;
fs->inode_walk = fatfs_inode_walk;
fs->istat = fatfs_istat;
fs->file_add_meta = fatfs_inode_lookup;
fs->get_default_attr_type = fatfs_get_default_attr_type;
fs->load_attrs = fatfs_make_data_runs;
fs->dir_open_meta = fatfs_dir_open_meta;
fs->name_cmp = fatfs_name_cmp;
fs->fsstat = fatxxfs_fsstat;
fs->fscheck = fatfs_fscheck;
fs->close = fatfs_close;
fs->jblk_walk = fatfs_jblk_walk;
fs->jentry_walk = fatfs_jentry_walk;
fs->jopen = fatfs_jopen;
fatfs->is_cluster_alloc = fatxxfs_is_cluster_alloc;
fatfs->is_dentry = fatxxfs_is_dentry;
fatfs->dinode_copy = fatxxfs_dinode_copy;
fatfs->inode_lookup = fatxxfs_inode_lookup;
fatfs->inode_walk_should_skip_dentry = fatxxfs_inode_walk_should_skip_dentry;
fatfs->istat_attr_flags = fatxxfs_istat_attr_flags;
fatfs->dent_parse_buf = fatxxfs_dent_parse_buf;
// initialize the caches
tsk_init_lock(&fatfs->cache_lock);
tsk_init_lock(&fatfs->dir_lock);
fatfs->inum2par = NULL;
// Test to see if this is the odd Android case where the FAT entries have no short name
//
// If there are no entries found with the normal short name
// and we find more entries by removing the short name test for allocated directories, then assume
// this is the case where we have no short names
fatfs->subtype = TSK_FATFS_SUBTYPE_SPEC;
test_dir1 = tsk_fs_dir_open_meta(fs, fs->root_inum);
if (test_dir1 != NULL && test_dir1->names_used <= 4){ // At most four automatic directories ($MBR, $FAT1, $FAT1, $OrphanFiles)
TSK_FS_DIR * test_dir2; // to see if it's the Android FAT version
fatfs->subtype = TSK_FATFS_SUBTYPE_ANDROID_1;
test_dir2 = tsk_fs_dir_open_meta(fs, fs->root_inum);
if (test_dir2 != NULL && test_dir2->names_used > test_dir1->names_used){
fatfs->subtype = TSK_FATFS_SUBTYPE_ANDROID_1;
}
else{
fatfs->subtype = TSK_FATFS_SUBTYPE_SPEC;
}
tsk_fs_dir_close(test_dir2);
}
tsk_fs_dir_close(test_dir1);
return 0;
}
/* Return 1 if allocated, 0 if unallocated, and -1 if error */
int8_t
fatxxfs_is_cluster_alloc(FATFS_INFO *fatfs, TSK_DADDR_T clust)
{
TSK_DADDR_T content = 0;
if (fatfs_getFAT(fatfs, clust, &content))
return -1;
else if (content == FATFS_UNALLOC)
return 0;
else
return 1;
}
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