www.pudn.com > truecrypt-4.2-source-code.zip > Fat.c

/* Legal Notice: The source code contained in this file has been derived from 
   the source code of Encryption for the Masses 2.02a, which is Copyright (c) 
   1998-99 Paul Le Roux and which is covered by the 'License Agreement for 
   Encryption for the Masses'. Modifications and additions to that source code 
   contained in this file are Copyright (c) 2004-2006 TrueCrypt Foundation and 
   Copyright (c) 2004 TrueCrypt Team, and are covered by TrueCrypt License 2.0 
   the full text of which is contained in the file License.txt included in 
   TrueCrypt binary and source code distribution archives.  */ 
 
#include "Tcdefs.h" 
 
#include "Crypto.h" 
#include "Format.h" 
#include "Fat.h" 
#include "Progress.h" 
#ifdef _WIN32 
#include "Random.h" 
#endif 
 
#include  
 
void 
GetFatParams (fatparams * ft) 
{ 
	int fatsecs; 
	if(ft->cluster_size == 0)	// 'Default' cluster size 
	{ 
		if (ft->num_sectors * 512LL >= 256*BYTES_PER_GB) 
			ft->cluster_size = 128; 
		else if (ft->num_sectors * 512LL >= 64*BYTES_PER_GB) 
			ft->cluster_size = 64; 
		else if (ft->num_sectors * 512LL >= 16*BYTES_PER_GB) 
			ft->cluster_size = 32; 
		else if (ft->num_sectors * 512LL >= 8*BYTES_PER_GB) 
			ft->cluster_size = 16; 
		else if (ft->num_sectors * 512LL >= 128*BYTES_PER_MB) 
			ft->cluster_size = 8; 
		else if (ft->num_sectors * 512LL >= 64*BYTES_PER_MB) 
			ft->cluster_size = 4; 
		else if (ft->num_sectors * 512LL >= 32*BYTES_PER_MB) 
			ft->cluster_size = 2; 
		else 
			ft->cluster_size = 1; 
	} 
 
	// Geometry always set to SECTORS/1/1 
	ft->secs_track = 1;  
	ft->heads = 1;  
 
	ft->dir_entries = 512; 
	ft->fats = 2; 
	ft->create_time = (unsigned int) time (NULL); 
	ft->media = 0xf8; 
	ft->sector_size = SECTOR_SIZE; 
	ft->hidden = 63; 
 
	ft->size_root_dir = ft->dir_entries * 32; 
 
	// FAT12 
	ft->size_fat = 12; 
	ft->reserved = 2; 
	fatsecs = ft->num_sectors - (ft->size_root_dir + SECTOR_SIZE - 1) / SECTOR_SIZE - ft->reserved; 
	ft->cluster_count = (int) (((__int64) fatsecs * SECTOR_SIZE) / (ft->cluster_size * SECTOR_SIZE + 3)); 
	ft->fat_length = (((ft->cluster_count * 3 + 1) >> 1) + SECTOR_SIZE - 1) / SECTOR_SIZE; 
 
	if (ft->cluster_count >= 4085) // FAT16 
	{ 
		ft->size_fat = 16; 
		ft->reserved = 8; 
		fatsecs = ft->num_sectors - (ft->size_root_dir + SECTOR_SIZE - 1) / SECTOR_SIZE - ft->reserved; 
		ft->cluster_count = (int) (((__int64) fatsecs * SECTOR_SIZE) / (ft->cluster_size * SECTOR_SIZE + 4)); 
		ft->fat_length = (ft->cluster_count * 2 + SECTOR_SIZE - 1) / SECTOR_SIZE; 
	} 
	 
	if(ft->cluster_count >= 65525) // FAT32 
	{ 
		ft->size_fat = 32; 
		ft->reserved = 38; 
		fatsecs = ft->num_sectors - ft->reserved; 
		ft->size_root_dir = ft->cluster_size * SECTOR_SIZE; 
		ft->cluster_count = (int) (((__int64) fatsecs * SECTOR_SIZE) / (ft->cluster_size * SECTOR_SIZE + 8)); 
		ft->fat_length = (ft->cluster_count * 4 + SECTOR_SIZE - 1) / SECTOR_SIZE; 
	} 
 
	if (ft->num_sectors >= 65536 || ft->size_fat == 32) 
	{ 
		ft->sectors = 0; 
		ft->total_sect = ft->num_sectors; 
	} 
	else 
	{ 
		ft->sectors = ft->num_sectors; 
		ft->total_sect = 0; 
	} 
} 
 
void 
PutBoot (fatparams * ft, unsigned char *boot) 
{ 
	int cnt = 0; 
 
	boot[cnt++] = 0xeb;	/* boot jump */ 
	boot[cnt++] = 0x3c; 
	boot[cnt++] = 0x90; 
	memcpy (boot + cnt, "MSDOS5.0", 8); /* system id */ 
	cnt += 8; 
	memcpy (boot + cnt, &ft->sector_size, 2);	/* bytes per sector */ 
	cnt += 2; 
	memcpy (boot + cnt, &ft->cluster_size, 1);	/* sectors per cluster */ 
	cnt++; 
	memcpy (boot + cnt, &ft->reserved, 2);		/* reserved sectors */ 
	cnt += 2; 
	memcpy (boot + cnt, &ft->fats, 1);			/* 2 fats */ 
	cnt++; 
 
	if(ft->size_fat == 32) 
	{ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x00; 
	} 
	else 
	{ 
		memcpy (boot + cnt, &ft->dir_entries, 2);	/* 512 root entries */ 
		cnt += 2; 
	} 
 
	memcpy (boot + cnt, &ft->sectors, 2);			/* # sectors */ 
	cnt += 2; 
	memcpy (boot + cnt, &ft->media, 1);				/* media byte */ 
	cnt++; 
 
	if(ft->size_fat == 32)	 
	{ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x00; 
	} 
	else  
	{  
		memcpy (boot + cnt, &ft->fat_length, 2);	/* fat size */ 
		cnt += 2; 
	} 
 
	memcpy (boot + cnt, &ft->secs_track, 2);	/* # sectors per track */ 
	cnt += 2; 
	memcpy (boot + cnt, &ft->heads, 2);			/* # heads */ 
	cnt += 2; 
	memcpy (boot + cnt, &ft->hidden, 4);		/* # hidden sectors */ 
	cnt += 4; 
	memcpy (boot + cnt, &ft->total_sect, 4);	/* # huge sectors */ 
	cnt += 4; 
 
	if(ft->size_fat == 32) 
	{ 
		memcpy (boot + cnt, &ft->fat_length, 4); cnt += 4;	/* fat size 32 */ 
		boot[cnt++] = 0x00;	/* ExtFlags */ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x00;	/* FSVer */ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x02;	/* RootClus */ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x01;	/* FSInfo */ 
		boot[cnt++] = 0x00; 
		boot[cnt++] = 0x06;	/* BkBootSec */ 
		boot[cnt++] = 0x00; 
		memset(boot+cnt, 0, 12); cnt+=12;	/* Reserved */ 
	} 
 
	boot[cnt++] = 0x00;	/* drive number */   // FIXED 80 > 00 
	boot[cnt++] = 0x00;	/* reserved */ 
	boot[cnt++] = 0x29;	/* boot sig */ 
	memcpy (boot + cnt, &ft->create_time, 4);	/* vol id */ 
	cnt += 4; 
	memcpy (boot + cnt, ft->volume_name, 11);	/* vol title */ 
	cnt += 11; 
 
	switch(ft->size_fat) /* filesystem type */ 
	{ 
		case 12: memcpy (boot + cnt, "FAT12   ", 8); break; 
		case 16: memcpy (boot + cnt, "FAT16   ", 8); break; 
		case 32: memcpy (boot + cnt, "FAT32   ", 8); break; 
	} 
	cnt += 8; 
 
	memset (boot + cnt, 0, ft->size_fat==32 ? 420:448);	/* boot code */ 
	cnt += ft->size_fat==32 ? 420:448; 
	boot[cnt++] = 0x55; 
	boot[cnt++] = 0xaa;	/* boot sig */ 
} 
 
/* FAT32 FSInfo */ 
PutFSInfo (unsigned char *sector) 
{ 
	memset (sector, 0, 512); 
	sector[3]=0x41; /* LeadSig */ 
	sector[2]=0x61;  
	sector[1]=0x52;  
	sector[0]=0x52;  
	sector[484+3]=0x61; /* StrucSig */ 
	sector[484+2]=0x41;  
	sector[484+1]=0x72;  
	sector[484+0]=0x72;  
	sector[488+3]=0xff; /* Free_Count */ 
	sector[488+2]=0xff; 
	sector[488+1]=0xff; 
	sector[488+0]=0xff; 
	sector[492+3]=0xff; /* Nxt_Free */ 
	sector[492+2]=0xff; 
	sector[492+1]=0xff; 
	sector[492+0]=0xff; 
	sector[508+3]=0xaa; /* TrailSig */ 
	sector[508+2]=0x55; 
	sector[508+1]=0x00; 
	sector[508+0]=0x00; 
} 
 
 
int 
FormatFat (unsigned __int64 startSector, fatparams * ft, void * dev, PCRYPTO_INFO cryptoInfo, BOOL quickFormat) 
{ 
	int write_buf_cnt = 0; 
	char sector[SECTOR_SIZE], *write_buf; 
	unsigned __int64 nSecNo = startSector; 
	int x, n; 
	int retVal; 
	char temporaryKey[DISKKEY_SIZE]; 
 
#ifdef _WIN32 
	LARGE_INTEGER startOffset; 
	LARGE_INTEGER newOffset; 
 
	// Seek to start sector 
	startOffset.QuadPart = startSector * SECTOR_SIZE; 
	if (!SetFilePointerEx ((HANDLE) dev, startOffset, &newOffset, FILE_BEGIN) 
		|| newOffset.QuadPart != startOffset.QuadPart) 
	{ 
		return ERR_VOL_SEEKING; 
	} 
#endif 
 
	/* Write the data area */ 
 
	write_buf = (char *)TCalloc (WRITE_BUF_SIZE); 
	memset (sector, 0, sizeof (sector)); 
 
	PutBoot (ft, (unsigned char *) sector); 
	if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
		cryptoInfo) == FALSE) 
		goto fail; 
 
	/* fat32 boot area */ 
	if (ft->size_fat == 32)				 
	{ 
		/* fsinfo */ 
		PutFSInfo((unsigned char *) sector); 
		if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
			cryptoInfo) == FALSE) 
			goto fail; 
 
		/* reserved */ 
		while (nSecNo - startSector < 6) 
		{ 
			memset (sector, 0, sizeof (sector)); 
			sector[508+3]=0xaa; /* TrailSig */ 
			sector[508+2]=0x55; 
			if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
				cryptoInfo) == FALSE) 
				goto fail; 
		} 
		 
		/* bootsector backup */ 
		memset (sector, 0, sizeof (sector)); 
		PutBoot (ft, (unsigned char *) sector); 
		if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
				 cryptoInfo) == FALSE) 
			goto fail; 
 
		PutFSInfo((unsigned char *) sector); 
		if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
			cryptoInfo) == FALSE) 
			goto fail; 
	} 
 
	/* reserved */ 
	while (nSecNo - startSector < (unsigned int)ft->reserved) 
	{ 
		memset (sector, 0, sizeof (sector)); 
		if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
			cryptoInfo) == FALSE) 
			goto fail; 
	} 
 
	/* write fat */ 
	for (x = 1; x <= ft->fats; x++) 
	{ 
		for (n = 0; n < ft->fat_length; n++) 
		{ 
			memset (sector, 0, SECTOR_SIZE); 
 
			if (n == 0) 
			{ 
				unsigned char fat_sig[12]; 
				if (ft->size_fat == 32) 
				{ 
					fat_sig[0] = (unsigned char) ft->media; 
					fat_sig[1] = fat_sig[2] = 0xff; 
					fat_sig[3] = 0x0f; 
					fat_sig[4] = fat_sig[5] = fat_sig[6] = 0xff; 
					fat_sig[7] = 0x0f; 
					fat_sig[8] = fat_sig[9] = fat_sig[10] = 0xff; 
					fat_sig[11] = 0x0f; 
					memcpy (sector, fat_sig, 12); 
				}				 
				else if (ft->size_fat == 16) 
				{ 
					fat_sig[0] = (unsigned char) ft->media; 
					fat_sig[1] = 0xff; 
					fat_sig[2] = 0xff; 
					fat_sig[3] = 0xff; 
					memcpy (sector, fat_sig, 4); 
				} 
				else if (ft->size_fat == 12) 
				{ 
					fat_sig[0] = (unsigned char) ft->media; 
					fat_sig[1] = 0xff; 
					fat_sig[2] = 0xff; 
					fat_sig[3] = 0x00; 
					memcpy (sector, fat_sig, 4); 
				} 
			} 
 
			if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
				    cryptoInfo) == FALSE) 
				goto fail; 
		} 
	} 
 
 
	/* write rootdir */ 
	for (x = 0; x < ft->size_root_dir / SECTOR_SIZE; x++) 
	{ 
		memset (sector, 0, SECTOR_SIZE); 
		if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
				 cryptoInfo) == FALSE) 
			goto fail; 
 
	} 
 
	/* Fill the rest of the data area with random data */ 
 
	if(!quickFormat) 
	{ 
		/* Generate a random temporary key set to be used for "dummy" encryption that will fill 
		the free disk space (data area) with random data.  This is necessary for plausible 
		deniability of hidden volumes (and also reduces the amount of predictable plaintext 
		within the volume). */ 
 
		RandgetBytes (temporaryKey, EAGetKeySize (cryptoInfo->ea), FALSE); 	// Temporary master key 
		RandgetBytes (cryptoInfo->iv, sizeof cryptoInfo->iv, FALSE);		// Secondary key (LRW mode) 
 
		retVal = EAInit (cryptoInfo->ea, temporaryKey, cryptoInfo->ks); 
		if (retVal != 0) 
		{ 
			burn (temporaryKey, sizeof(temporaryKey)); 
			return retVal; 
		} 
		if (!EAInitMode (cryptoInfo)) 
		{ 
			burn (temporaryKey, sizeof(temporaryKey)); 
			return ERR_MODE_INIT_FAILED; 
		} 
 
		x = ft->num_sectors - ft->reserved - ft->size_root_dir / SECTOR_SIZE - ft->fat_length * 2; 
		while (x--) 
		{ 
			/* Generate random plaintext. Note that reused plaintext blocks are not a concern 
			here since LRW mode is designed to hide patterns. Furthermore, patterns in plaintext 
			do occur commonly on media in the "real world", so it might actually be a fatal 
			mistake to try to avoid them completely. */ 
#if defined(RNG_POOL_SIZE) && (RNG_POOL_SIZE < SECTOR_SIZE)  
			RandpeekBytes (sector, RNG_POOL_SIZE); 
			RandpeekBytes (sector + RNG_POOL_SIZE, SECTOR_SIZE - RNG_POOL_SIZE); 
#else 
			if ((nSecNo & 0xff) == 0) 
				RandpeekBytes (sector, SECTOR_SIZE); 
#endif 
			// Encrypt the random plaintext and write it to the disk 
			if (WriteSector (dev, sector, write_buf, &write_buf_cnt, &nSecNo, 
				cryptoInfo) == FALSE) 
				goto fail; 
		} 
		UpdateProgressBar (nSecNo); 
	} 
	else 
		UpdateProgressBar (ft->num_sectors); 
 
	if (write_buf_cnt != 0 
#ifdef _WIN32 
		&& _lwrite ((HFILE)dev, write_buf, write_buf_cnt) == HFILE_ERROR) 
#else 
		&& fwrite (write_buf, 1, write_buf_cnt, (FILE *)dev) != (size_t)write_buf_cnt) 
#endif 
		goto fail; 
 
	TCfree (write_buf); 
	burn (temporaryKey, sizeof(temporaryKey)); 
	return 0; 
 
fail: 
 
	TCfree (write_buf); 
	burn (temporaryKey, sizeof(temporaryKey)); 
	return ERR_OS_ERROR; 
}