2007.11.02 20:26 "[Tiff] Recent bug fixes in CVS head", by Frank Warmerdam

2007.11.22 08:05 "RE: [Tiff] tag content size limit?", by Tillaart, Rob van den


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


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)
        if ((uint64)(4*1024*1024/desttypesize)<direntry->tdir_count)

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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