ExifTool trips over SHORT-typed StripOffsets values in TIFF files

[marhop]

Hi,

ExifTool 12.00 seems to have a problem with StripOffsets pointers in TIFF files if they have type SHORT instead of LONG (both are permitted by the TIFF 6.0 spec).

Consider the attached files:

• stripoffsets-short-0.tif has three StripOffsets values of type SHORT (source)
• stripoffsets-long-0.tif is the same file with exactly one difference: the three StripOffsets values have type LONG

Writing some tag to these files (I used exiftool -ISO=42) results in these files:

• stripoffsets-short-1.tif is damaged, it has three StripByteCounts values (0 16448 8100, first one is zero?!) but only two StripOffsets values (248 8348); the file cannot be displayed by various viewers and exiftool -validate -warning -a issues matching warnings:
  • Wrong number of values in IFD0 0x0111 StripOffsets
  • Oversized IFD0 StripByteCounts (24548 bytes, but expected 24300)
• stripoffsets-long-1.tif is OK though

Any idea what's going wrong here?

Thanks,
Martin

[boardhead]

Hi Martin,

Wow. This is serious. I guess that using 16-bit offsets is very rare or I would have seen this before.

I'll get on this right away.

• Phil

[boardhead]

This should be fixed in version 12.01 (just released)

Thanks for this report!

[marhop]

Hi Phil,

This is awesome, how can you be so fast? It took me longer to find this bug than it took you to fix it. :-)

using 16-bit offsets is very rare

Agreed! This file is just a contrived example. I don't expect to see 16-bit offsets in many real-world files since these would have to be quite small.

As far as I'm concerned this issue may be closed now.

Cheers,
Martin

[boardhead]

Great, thanks!