Public bug reported:
The patch debian/patches/CVE-2014-8128-5.patch appears to break saving TIFF
files with compression predictor.
It seems the data is correctly saved, but the "predictor" tag is not, which
prevents reading the data correctly again.
This happens both on precise (release 3.9.5-2ubuntu1.7) and on trusty
(release 4.0.3-7ubuntu0.2).
I'm attaching an example TIFF file "small.tiff" for showing the
behaviour. It is compressed in LZW without predictor, so it is
written/read correctly.
However, if you recompress it with this command, the error happens:
$ tiffcp -c lzw:2 small.tiff small-c2.tiff
Then displaying it in eog shows a completely different image. Tiffinfo
indicates a problem with the tags:
$ tiffinfo small-c2-bad.tiff | grep Predictor
TIFFReadDirectory: Warning, small-c2-bad.tiff: unknown field with tag 8224
(0x2020) encountered.
Comparing it with a good version of the file (generated with a previous version
of libtiff):
$ tiffinfo small-c2-good.tiff | grep Predictor
Predictor: horizontal differencing 2 (0x2)
$ tiffcmp small-c2.tiff small-c2-good.tiff
TIFFReadDirectory: Warning, small-c2-bad.tiff: unknown field with tag 8224
(0x2020) encountered.
Predictor tag appears only in small-c2-good.tiff
** Affects: tiff (Ubuntu)
Importance: Undecided
Status: New
** Attachment added: "Example TIFF file without predictor"
https://bugs.launchpad.net/bugs/1439186/+attachment/4362958/+files/small.tiff
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https://bugs.launchpad.net/bugs/1439186
Title:
[REGRESSION] Predictor tag fails to be written correctly
Status in tiff package in Ubuntu:
New
Bug description:
The patch debian/patches/CVE-2014-8128-5.patch appears to break saving TIFF
files with compression predictor.
It seems the data is correctly saved, but the "predictor" tag is not, which
prevents reading the data correctly again.
This happens both on precise (release 3.9.5-2ubuntu1.7) and on trusty
(release 4.0.3-7ubuntu0.2).
I'm attaching an example TIFF file "small.tiff" for showing the
behaviour. It is compressed in LZW without predictor, so it is
written/read correctly.
However, if you recompress it with this command, the error happens:
$ tiffcp -c lzw:2 small.tiff small-c2.tiff
Then displaying it in eog shows a completely different image. Tiffinfo
indicates a problem with the tags:
$ tiffinfo small-c2-bad.tiff | grep Predictor
TIFFReadDirectory: Warning, small-c2-bad.tiff: unknown field with tag 8224
(0x2020) encountered.
Comparing it with a good version of the file (generated with a previous
version of libtiff):
$ tiffinfo small-c2-good.tiff | grep Predictor
Predictor: horizontal differencing 2 (0x2)
$ tiffcmp small-c2.tiff small-c2-good.tiff
TIFFReadDirectory: Warning, small-c2-bad.tiff: unknown field with tag 8224
(0x2020) encountered.
Predictor tag appears only in small-c2-good.tiff
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/tiff/+bug/1439186/+subscriptions
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