Bug#1057270: libimager-perl: FTBFS: t/t10tiff.t failure

[Niko Tyni]

Control: forwarded -1 https://github.com/tonycoz/imager/issues/522

On Sat, Dec 02, 2023 at 07:24:39PM +0200, Niko Tyni wrote:
> On Sat, Dec 02, 2023 at 01:40:51PM +0100, gregor herrmann wrote:
> > On Sat, 02 Dec 2023 14:24:01 +0200, Niko Tyni wrote:

> It can be reproduced like this with the libimager-perl binaries
> currently in sid and every tiff file I tried with, for example
> test/images/palette-1c-8b.tiff in src:tiff.

Further simplifying, this fails in the exact same way:

  $ perl -MImager -e '$i=Imager->new; Imager::init_log(); $i->read(file => shift) or die $i->_error_as_msg()' tiff/test/images/palette-1c-8b.tiff

> I note it says "filesize 0". The patch determines the file size with
> 
>   uint64_t filesize = TIFFGetFileSize(tif);
> 
> and TIFFGetFileSize() is in src:tiff libtiff/tiffiop.h as follows:
> 
>   #define TIFFGetFileSize(tif) ((*(tif)->tif_sizeproc)((tif)->tif_clientdata))
 
>From http://www.simplesystems.org/libtiff/functions/TIFFOpen.html

  TIFFClientOpen() is like TIFFOpen() except that the caller supplies a
  collection of functions that the library will use to do UNIX-like I/O
  operations. The readproc and writeproc functions are called to read and
  write data at the current file position. seekproc is called to change
  the current file position à la lseek() (2). closeproc is invoked to
  release any resources associated with an open file. sizeproc is invoked
  to obtain the size in bytes of a file. mapproc and unmapproc are called
  to map and unmap a file's contents in memory; c.f. mmap() (2) and
  munmap() (2). The clientdata parameter is an opaque "handle" passed to
  the client-specified routines passed as parameters to TIFFClientOpen().

>From https://sources.debian.org/src/libimager-perl/1.020%2Bdfsg-1/TIFF/imtiff.c/#L302

  static toff_t sizeproc(thandle_t x) {
  	return 0;
  }

which is used as the TIFFClientOpen() argument in i_readtiff_wiol():

  https://sources.debian.org/src/libimager-perl/1.020%2Bdfsg-1/TIFF/imtiff.c/#L710

So it looks like libimager-perl is always saying the file size is 0,
and this hasn't hurt earlier but now does with the src:tiff CVE-2023-6277
patch.

Not sure where this leaves us, but I've just reported it at

  https://github.com/tonycoz/imager/issues/522

-- 
Niko