Excessive CPU in HDR image - IM6 SVN - convert - 3c1c3e63

[JodieC]

Source file:
https://www.dropbox.com/s/o2dwadu5ti11nwn/3c1c3e63?dl=0

To reproduce:
limit cpu to n seconds via

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ulimit -St 600

Then run

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convert 3c1c3e63 null: 

or

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identify 3c1c3e63

Output:
With the ulimit:
Aborted
Without the ulimit:
No output... It just runs for hours.

I don't have a handy BT on this right now, but I did run it through valgrind --tool=callgrind for about 20-30 seconds or so. When I pulled it into kcachegrind it apparently spent 800K calls in ReadHDRImage and 500K to ReadBlobByte. That's a lot for a <1KB file.

I'm running on Im6 from SVN rev17767.

System Details:
AMD64
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

Found with American Fuzzy Lop ( http://lcamtuf.coredump.cx/afl/ )

[dlemstra]

I submitted a patch to fix this infinite loop. It now quits with the following message:

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D:\Images\Fuzz>identify 3c1c3e63
identify.exe: Improper image header `3c1c3e63' @ error/hdr.c/ReadHDRImage/379.

[JodieC]

Dirk:
Thanks for the patch. I have some others that are similar that I'll get submitted.


For Bastien:
The patches for this are in:
http://trac.imagemagick.org/changeset/17845
http://trac.imagemagick.org/changeset/17846

[JodieC]

Can you confirm these 2 for this issue?

[dlemstra]

17845 is for IM7 and 17846 is for IM6. You most likely only need the latter.