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Date: Sun, 06 Dec 2009 01:45:15 +0000
From: Greg Chicares <gchicares AT sbcglobal DOT net>
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Subject: Re: Hippo icon for cygwin...
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On 2009-12-05 14:27Z, Charles Wilson wrote:
> Greg Chicares wrote:
>> Might this file:
>>   1a652c4c8c31b80c85d6cbc2b4093060 *hippo.ico
>> be somehow malformed? My computer BSODs every time I try to view
>> it in 'irfanview'. This has happened three times in a row.
> 
> BSOD? Well, *any* BSOD is by definition a bug inside ring 0 (e.g. the
> core Windows kernel, or a graphics driver.  So, it isn't *.ico's fault.

Yes, apparently it's an XP SP1 kernel defect: in 'win32.sys',
PAGE_FAULT_IN_NONPAGED_AREA, STOP 0x00000050.

I also tried the original .ico on an XP SP2 machine, which produced
a different BSOD. That machine was set to reboot itself upon BSOD,
so I didn't have time to record the message; but the program name
began with 'ati', so it was almost certainly a graphics driver.

But those are defects in ring-zero programs, so it's their job to
avoid crashing no matter what .ico file is handed to them. The
resulting vulnerability is their fault--not the .ico's fault.

BTW, both these machines have no known hardware problems, and
recent full runs of memtest86 indicate that their RAM is fine.

> Still, it'd be good to avoid...
> 
>> I tried opening the icon file in gimp-2.2.4, which crashed with:
>>   winicon.exe caused an Access Violation at location 00402795
>>   in module winicon.exe Reading from location 00000008.
>> (no BSOD). Yet the icon displays successfully in 'windows explorer'.
> 
> That's a pretty old version of gimp...

It's a native msw build that was released 2005-03-03: quite old,
I agree. Still, I'm probably not the only person running Cygwin
on a 2005-vintage system, so it's good to isolate the problem...

>> An .ico file actually can cause an application to crash:
>>   http://securitytracker.com/alerts/2007/Jun/1018202.html
>> That tracker says ms planned to patch the problem, but right now
>> I'm using XP SP1, so I wouldn't have that patch.
> 
> Hmmm.  Well, the .ico contains the *vista*-approved sizes:

Okay, yet many large-corporation IT departments are sticking
with XP for the foreseeable future, even for brand-new machines.
And apparently the vista-sized icons aren't gracefully ignored
by XP (SP1 at least), no matter what ms may say. BTW, the
graphics drivers on the SP2 machine were current when I checked
them for updates about two weeks ago.

> Supposedly, the 256x256 png-compressed size should be ignored on
> platforms that do not support it -- but maybe that's causing your
> problem.  Try the attached version, which omits the 256x256 resolution.

This new .ico works fine in every graphics program I can find,
even on the XP SP1 machine--specifically including the two
programs that failed with the original icon.

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