2007.11.02 20:26 "[Tiff] Recent bug fixes in CVS head", by Frank
Warmerdam
Thread
2007.11.22 08:05 "RE: [Tiff] tag content size limit?", by Tillaart, Rob van den
Hi,
If I understand correctly the code lines you refering to are about the number of Directory Entries in an IFD. As far as I know this count is not related to the number of strips.
Or could it be some unwanted sideeffect? overflow or overwritten memory buffer? Does the value of tdir_count make sense?
>From the point of strip administration I see the following logical restrictions:
1 <= StripByteCounts <= RowsPerStrip * ImageWidth
1 <= # RowsPerStrip <= ImageLength
recommendation each strip is about 8K (6.0 spec page 39) but
that seems to me a historical practical buffersize.
1 <= # StripOffsets < FileSize/StripByteCounts
Furthermore all offsets should comply to
TiffHeadersize < offset < filesize
Conclusion no reason for some 4MB limit,
sofar my 2 cents,
rob tillaart
> -----Original Message-----
> From: tiff-bounces@lists.maptools.org
> [mailto:tiff-bounces@lists.maptools.org] On Behalf Of Frank Warmerdam
Joris,
I have run into problems with my attempts to create a TIFF file with 1333333 strips. Attempts to read the the stripoffsets tag results in an error in TIFFReadDirEntryErr() with this logic:
if ((uint64)(4*1024*1024/typesize)<direntry->tdir_count)
return(TIFFReadDirEntryErrSizesan);
if ((uint64)(4*1024*1024/desttypesize)<direntry->tdir_count)
return(TIFFReadDirEntryErrSizesan);The logic seems to assume that any tag contents larger than 4MB likely implies a corrupt file. Is there a particular reason we should put in place such a restriction? Should the restriction be removed? Relaxed? (perhaps upped to any tag value larger than 1GB is likely corruption? or any tag value larger than the file itself is?
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