Problem with miniFAT sectors when numMiniFatSectors > 1

[adepasquale]

Hello,
I noticed an issue when parsing documents with more then one MiniFAT sectors.

version : major = 3, minor = 0x003e
sectorShift = 9
numDirectorySectors = 0
numFatSectors = 1
firstDirectorySectorLocation = 52
transactionSignatureNumber = 0
firstMiniFatSectorLocation = 55
numMiniFatSectors = 2
firstDifatSectorLocation = END
numDifatSectors = 0
difat size=1
 51
dataSize=45056(0xb000)
sectorSize=512
# of mini fat sectors = 2
exception:ms:cfb:FatSectors:bad idx:128

00000000: d0cf 11e0 a1b1 1ae1 0000 0000 0000 0000  ................
00000010: 0000 0000 0000 0000 3e00 0300 feff 0900  ........>.......
00000020: 0600 0000 0000 0000 0000 0000 0100 0000  ................
00000030: 3400 0000 0000 0000 0010 0000 3700 0000  4...........7...
00000040: 0200 0000 feff ffff 0000 0000 3300 0000  ............3...
00000050: ffff ffff ffff ffff ffff ffff ffff ffff  ................
...
000001f0: ffff ffff ffff ffff ffff ffff ffff ffff  ................

I have added a check to avoid this exception but it doesn't seem to be enough, probably because the additional MiniFAT sectors are not consecutive? I can share the sample document via email if it helps.

adepasquale@7f5c00e

I haven't been able to find documentation about the location of additional MiniFAT sectors in case there's more than one (for this sample there are two). Anyway I have identified the locations below:

• 0x00007000 from the 0x00000037 in the header;
• 0x00009400 by manually analysing the rest of the file.

00007000: 0100 0000 0200 0000 0300 0000 0400 0000  ................
00007010: feff ffff 0600 0000 0700 0000 0800 0000  ................
00007020: 0900 0000 0a00 0000 feff ffff 0c00 0000  ................
00007030: 0d00 0000 0e00 0000 0f00 0000 1000 0000  ................
00007040: 1100 0000 1200 0000 1300 0000 1400 0000  ................
00007050: 1500 0000 1600 0000 1700 0000 1800 0000  ................
00007060: feff ffff 1a00 0000 1b00 0000 1c00 0000  ................
00007070: 1d00 0000 1e00 0000 1f00 0000 2000 0000  ............ ...
00007080: 2100 0000 2200 0000 2300 0000 2400 0000  !..."...#...$...
00007090: 2500 0000 2600 0000 2700 0000 2800 0000  %...&...'...(...
000070a0: 2900 0000 2a00 0000 2b00 0000 2c00 0000  )...*...+...,...
000070b0: 2d00 0000 2e00 0000 2f00 0000 3000 0000  -......./...0...
000070c0: 3100 0000 3200 0000 3300 0000 3400 0000  1...2...3...4...
000070d0: 3500 0000 3600 0000 3700 0000 3800 0000  5...6...7...8...
000070e0: 3900 0000 3a00 0000 3b00 0000 3c00 0000  9...:...;...<...
000070f0: 3d00 0000 3e00 0000 3f00 0000 4000 0000  =...>...?...@...
00007100: 4100 0000 4200 0000 4300 0000 4400 0000  A...B...C...D...
00007110: feff ffff 4600 0000 4700 0000 4800 0000  ....F...G...H...
00007120: 4900 0000 4a00 0000 4b00 0000 4c00 0000  I...J...K...L...
00007130: 4d00 0000 4e00 0000 4f00 0000 5000 0000  M...N...O...P...
00007140: 5100 0000 5200 0000 5300 0000 5400 0000  Q...R...S...T...
00007150: 5500 0000 5600 0000 5700 0000 5800 0000  U...V...W...X...
00007160: 5900 0000 5a00 0000 5b00 0000 5c00 0000  Y...Z...[...\...
00007170: 5d00 0000 5e00 0000 5f00 0000 6000 0000  ]...^..._...`...
00007180: feff ffff 6200 0000 6300 0000 6400 0000  ....b...c...d...
00007190: 6500 0000 6600 0000 6700 0000 6800 0000  e...f...g...h...
000071a0: 6900 0000 6a00 0000 6b00 0000 6c00 0000  i...j...k...l...
000071b0: 6d00 0000 6e00 0000 6f00 0000 7000 0000  m...n...o...p...
000071c0: 7100 0000 feff ffff 7300 0000 7400 0000  q.......s...t...
000071d0: 7500 0000 7600 0000 7700 0000 7800 0000  u...v...w...x...
000071e0: 7900 0000 7a00 0000 7b00 0000 7c00 0000  y...z...{...|...
000071f0: 7d00 0000 7e00 0000 7f00 0000 8000 0000  }...~...........

00009400: 8100 0000 8200 0000 8300 0000 8400 0000  ................
00009410: 8500 0000 8600 0000 8700 0000 8800 0000  ................
00009420: 8900 0000 8a00 0000 8b00 0000 8c00 0000  ................
00009430: 8d00 0000 8e00 0000 8f00 0000 9000 0000  ................
00009440: 9100 0000 9200 0000 9300 0000 9400 0000  ................
00009450: 9500 0000 9600 0000 9700 0000 9800 0000  ................
00009460: 9900 0000 9a00 0000 9b00 0000 9c00 0000  ................
00009470: 9d00 0000 9e00 0000 9f00 0000 a000 0000  ................
00009480: a100 0000 a200 0000 a300 0000 a400 0000  ................
00009490: a500 0000 a600 0000 a700 0000 a800 0000  ................
000094a0: feff ffff aa00 0000 ab00 0000 ac00 0000  ................
000094b0: ad00 0000 ae00 0000 af00 0000 b000 0000  ................
000094c0: b100 0000 b200 0000 feff ffff b400 0000  ................
000094d0: feff ffff b600 0000 b700 0000 b800 0000  ................
000094e0: b900 0000 feff ffff bb00 0000 bc00 0000  ................
000094f0: bd00 0000 be00 0000 bf00 0000 c000 0000  ................
00009500: c100 0000 c200 0000 feff ffff c400 0000  ................
00009510: feff ffff c600 0000 c700 0000 c800 0000  ................
00009520: c900 0000 feff ffff cb00 0000 feff ffff  ................
00009530: ffff ffff ffff ffff ffff ffff ffff ffff  ................
...
000095f0: ffff ffff ffff ffff ffff ffff ffff ffff  ................

[herumi]

Thank you for your detailed explanation and pull req.
I want to check it by the files which caused this problem if possible.
Could you mind giving me the file?

[adepasquale]

File sent to your N I F T Y dot C O M email

[herumi]

Thank you. I got it and will see it.

[adepasquale]

Hello, did you find some time to investigate the issue?

[herumi]

I'm sorry to wait for long time. I'm now busy so can not take time to remember the specification of the file format and improve it.