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Subject: Re: ImageMagick maybe broken by libgs9 upgrade
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Message-ID: <7577f575-9a66-bdb6-1cb9-30a6f9e305ad@gmail.com>
Date: Wed, 24 Jun 2020 20:21:56 +0200
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From: Marco Atzeri via Cygwin <cygwin@cygwin.com>
Reply-To: Marco Atzeri <marco.atzeri@gmail.com>
Cc: emilyw@yahoo.com
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On 24.06.2020 12:24, Ken Brown via Cygwin wrote:
> On 6/24/2020 1:30 AM, Marco Atzeri via Cygwin wrote:
>> On 23.06.2020 23:02, Marco Atzeri wrote:
>>> On 23.06.2020 22:56, Ken Brown via Cygwin wrote:
>>>>
>>>> I think I've found the problem, although it will take patching and 
>>>> rebuilding ImageMagick (which I haven't done) to confirm that I'm 
>>>> right.
>>>>
>>>> In the ImageMagick source file coders/ps.c:237, there's a call to 
>>>> ghost_info->new_instance, a.k.a. gsapi_new_instance (see line 214). 
>>>> The documentation of the latter in the ghostscript sources 
>>>> (psi/iapi.c:57) says that the first argument pinstance should 
>>>> satisfy *pinstance == NULL in the first call to that function.
>>>>
>>>> But *pinstance in this call is the variable 'interpreter', defined 
>>>> without initialization in ps.c:191.  As a result, **pinstance 
>>>> contains garbage, and the program eventually crashes when it tries 
>>>> to dereference a garbage pointer.
>>>>
>>>> The fix, if I'm right, is to initialize interpreter to NULL in 
>>>> ps.c:191.
>>>>
>>>> Ken
>>>
>>> Noted.
>>>
>>> Regards
>>> MArco
>>>
>>
>> a test ImageMagick-6.9.10.11-3 is going up.
>> Let me know if it solves the problem
> 
> That fixes it for my .eps file.  I didn't think of it before, but a 
> similar patch to coders/pdf.c:201 will be needed for .pdf files.  I 
> won't be able to test that because I haven't found a .pdf file that 
> exhibits the problem.
> 
> Ken
> 


test version 6.9.10.11-4 is going up.

If Emily tests with her pdf files, it will be nice

Regards
Marco

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