1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
|
/*
Legal Notice: Some portions of the source code contained in this file were
derived from the source code of TrueCrypt 7.1a, which is
Copyright (c) 2003-2012 TrueCrypt Developers Association and which is
governed by the TrueCrypt License 3.0, also from the source code of
Encryption for the Masses 2.02a, which is Copyright (c) 1998-2000 Paul Le Roux
and which is governed by the 'License Agreement for Encryption for the Masses'
Modifications and additions to the original source code (contained in this file)
and all other portions of this file are Copyright (c) 2013-2017 IDRIX
and are governed by the Apache License 2.0 the full text of which is
contained in the file License.txt included in VeraCrypt binary and source
code distribution packages. */
#include "Common/Tcdefs.h"
#include "Platform/Platform.h"
#include "Volume/VolumeHeader.h"
#include "FatFormatter.h"
#include "RandomNumberGenerator.h"
namespace VeraCrypt
{
struct fatparams
{
char volume_name[11];
uint32 num_sectors; /* total number of sectors */
uint32 cluster_count; /* number of clusters */
uint32 size_root_dir; /* size of the root directory in bytes */
uint32 size_fat; /* size of FAT */
uint32 fats;
uint32 media;
uint32 cluster_size;
uint32 fat_length;
uint16 dir_entries;
uint16 sector_size;
uint32 hidden;
uint16 reserved;
uint16 sectors;
uint32 total_sect;
uint16 heads;
uint16 secs_track;
};
static void GetFatParams (fatparams * ft)
{
uint64 volumeSize = (uint64) ft->num_sectors * ft->sector_size;
unsigned int fatsecs;
if(ft->cluster_size == 0) // 'Default' cluster size
{
uint32 clusterSize;
// Determine optimal cluster size to minimize FAT size (mounting delay), maximize number of files, keep 4 KB alignment, etc.
if (volumeSize >= 2 * BYTES_PER_TB)
clusterSize = 256 * BYTES_PER_KB;
else if (volumeSize >= 512 * BYTES_PER_GB)
clusterSize = 128 * BYTES_PER_KB;
else if (volumeSize >= 128 * BYTES_PER_GB)
clusterSize = 64 * BYTES_PER_KB;
else if (volumeSize >= 64 * BYTES_PER_GB)
clusterSize = 32 * BYTES_PER_KB;
else if (volumeSize >= 32 * BYTES_PER_GB)
clusterSize = 16 * BYTES_PER_KB;
else if (volumeSize >= 16 * BYTES_PER_GB)
clusterSize = 8 * BYTES_PER_KB;
else if (volumeSize >= 512 * BYTES_PER_MB)
clusterSize = 4 * BYTES_PER_KB;
else if (volumeSize >= 256 * BYTES_PER_MB)
clusterSize = 2 * BYTES_PER_KB;
else if (volumeSize >= 1 * BYTES_PER_MB)
clusterSize = 1 * BYTES_PER_KB;
else
clusterSize = 512;
ft->cluster_size = clusterSize / ft->sector_size;
if (ft->cluster_size == 0)
ft->cluster_size = 1;
if (ft->cluster_size * ft->sector_size > TC_MAX_FAT_CLUSTER_SIZE)
ft->cluster_size = TC_MAX_FAT_CLUSTER_SIZE / ft->sector_size;
if (ft->cluster_size > 128)
ft->cluster_size = 128;
}
if (volumeSize <= TC_MAX_FAT_CLUSTER_SIZE * 4)
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->media = 0xf8;
ft->hidden = 0;
ft->size_root_dir = ft->dir_entries * 32;
// FAT12
ft->size_fat = 12;
ft->reserved = 2;
fatsecs = ft->num_sectors - (ft->size_root_dir + ft->sector_size - 1) / ft->sector_size - ft->reserved;
ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
ft->fat_length = (((ft->cluster_count * 3 + 1) >> 1) + ft->sector_size - 1) / ft->sector_size;
if (ft->cluster_count >= 4085) // FAT16
{
ft->size_fat = 16;
ft->reserved = 2;
fatsecs = ft->num_sectors - (ft->size_root_dir + ft->sector_size - 1) / ft->sector_size - ft->reserved;
ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
ft->fat_length = (ft->cluster_count * 2 + ft->sector_size - 1) / ft->sector_size;
}
if(ft->cluster_count >= 65525) // FAT32
{
ft->size_fat = 32;
ft->reserved = 32 - 1;
do
{
ft->reserved++;
fatsecs = ft->num_sectors - ft->reserved;
ft->size_root_dir = ft->cluster_size * ft->sector_size;
ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
ft->fat_length = (ft->cluster_count * 4 + ft->sector_size - 1) / ft->sector_size;
// Align data area on TC_MAX_VOLUME_SECTOR_SIZE
} while (ft->sector_size == TC_SECTOR_SIZE_LEGACY
&& (ft->reserved * ft->sector_size + ft->fat_length * ft->fats * ft->sector_size) % TC_MAX_VOLUME_SECTOR_SIZE != 0);
}
ft->cluster_count -= ft->fat_length * ft->fats / ft->cluster_size;
if (ft->num_sectors >= 65536 || ft->size_fat == 32)
{
ft->sectors = 0;
ft->total_sect = ft->num_sectors;
}
else
{
ft->sectors = (uint16) ft->num_sectors;
ft->total_sect = 0;
}
}
static void PutBoot (fatparams * ft, byte *boot, uint32 volumeId)
{
int cnt = 0;
boot[cnt++] = 0xeb; /* boot jump */
boot[cnt++] = (ft->size_fat == 32)? 0x58: 0x3c;
boot[cnt++] = 0x90;
memcpy (boot + cnt, "MSDOS5.0", 8); /* system id */
cnt += 8;
*(int16 *)(boot + cnt) = Endian::Little (ft->sector_size); /* bytes per sector */
cnt += 2;
boot[cnt++] = (int8) ft->cluster_size; /* sectors per cluster */
*(int16 *)(boot + cnt) = Endian::Little (ft->reserved); /* reserved sectors */
cnt += 2;
boot[cnt++] = (int8) ft->fats; /* 2 fats */
if(ft->size_fat == 32)
{
boot[cnt++] = 0x00;
boot[cnt++] = 0x00;
}
else
{
*(int16 *)(boot + cnt) = Endian::Little (ft->dir_entries); /* 512 root entries */
cnt += 2;
}
*(int16 *)(boot + cnt) = Endian::Little (ft->sectors); /* # sectors */
cnt += 2;
boot[cnt++] = (int8) ft->media; /* media byte */
if(ft->size_fat == 32)
{
boot[cnt++] = 0x00;
boot[cnt++] = 0x00;
}
else
{
*(uint16 *)(boot + cnt) = Endian::Little ((uint16) ft->fat_length); /* fat size */
cnt += 2;
}
*(int16 *)(boot + cnt) = Endian::Little (ft->secs_track); /* # sectors per track */
cnt += 2;
*(int16 *)(boot + cnt) = Endian::Little (ft->heads); /* # heads */
cnt += 2;
*(int32 *)(boot + cnt) = Endian::Little (ft->hidden); /* # hidden sectors */
cnt += 4;
*(int32 *)(boot + cnt) = Endian::Little (ft->total_sect); /* # huge sectors */
cnt += 4;
if(ft->size_fat == 32)
{
*(int32 *)(boot + cnt) = Endian::Little (ft->fat_length); 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 */
*(int32 *)(boot + cnt) = volumeId;
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 */
static void PutFSInfo (byte *sector, fatparams *ft)
{
memset (sector, 0, ft->sector_size);
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;
// Free cluster count
*(uint32 *)(sector + 488) = Endian::Little (ft->cluster_count - ft->size_root_dir / ft->sector_size / ft->cluster_size);
// Next free cluster
*(uint32 *)(sector + 492) = Endian::Little ((uint32) 2);
sector[508+3] = 0xaa; /* TrailSig */
sector[508+2] = 0x55;
sector[508+1] = 0x00;
sector[508+0] = 0x00;
}
void FatFormatter::Format (WriteSectorCallback &writeSector, uint64 deviceSize, uint32 clusterSize, uint32 sectorSize)
{
fatparams fatParams;
#if TC_MAX_VOLUME_SECTOR_SIZE > 0xFFFF
#error TC_MAX_VOLUME_SECTOR_SIZE > 0xFFFF
#endif
fatParams.sector_size = (uint16) sectorSize;
if (deviceSize / fatParams.sector_size > 0xffffFFFF)
throw ParameterIncorrect (SRC_POS);
fatParams.num_sectors = (uint32) (deviceSize / fatParams.sector_size);
fatParams.cluster_size = clusterSize / fatParams.sector_size;
memcpy (fatParams.volume_name, "NO NAME ", 11);
GetFatParams (&fatParams);
fatparams *ft = &fatParams;
SecureBuffer sector (ft->sector_size);
uint32 sectorNumber = 0;
/* Write the data area */
sector.Zero();
uint32 volumeId;
RandomNumberGenerator::GetDataFast (BufferPtr ((byte *) &volumeId, sizeof (volumeId)));
PutBoot (ft, (byte *) sector, volumeId);
writeSector (sector); ++sectorNumber;
/* fat32 boot area */
if (ft->size_fat == 32)
{
/* fsinfo */
PutFSInfo((byte *) sector, ft);
writeSector (sector); ++sectorNumber;
/* reserved */
while (sectorNumber < 6)
{
sector.Zero();
sector[508+3] = 0xaa; /* TrailSig */
sector[508+2] = 0x55;
writeSector (sector); ++sectorNumber;
}
/* bootsector backup */
sector.Zero();
PutBoot (ft, (byte *) sector, volumeId);
writeSector (sector); ++sectorNumber;
PutFSInfo((byte *) sector, ft);
writeSector (sector); ++sectorNumber;
}
/* reserved */
while (sectorNumber < (uint32)ft->reserved)
{
sector.Zero();
writeSector (sector); ++sectorNumber;
}
/* write fat */
for (uint32 x = 1; x <= ft->fats; x++)
{
for (uint32 n = 0; n < ft->fat_length; n++)
{
sector.Zero();
if (n == 0)
{
byte fat_sig[12];
if (ft->size_fat == 32)
{
fat_sig[0] = (byte) 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] = (byte) 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] = (byte) ft->media;
fat_sig[1] = 0xff;
fat_sig[2] = 0xff;
fat_sig[3] = 0x00;
memcpy (sector, fat_sig, 4);
}
}
if (!writeSector (sector))
return;
}
}
/* write rootdir */
for (uint32 x = 0; x < ft->size_root_dir / ft->sector_size; x++)
{
sector.Zero();
if (!writeSector (sector))
return;
}
}
}
|