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List:       openjdk-2d-dev
Subject:    Re: [OpenJDK 2D-Dev] RFR: 8132850: java.lang.ArrayIndexOutOfBoundsException during text rendering wi
From:       Sergey Bylokhov <Sergey.Bylokhov () oracle ! com>
Date:       2015-08-13 18:35:05
Message-ID: 55CCE359.5090809 () oracle ! com
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Looks fine.

On 13.08.15 19:36, Jennifer Godinez wrote:
> Hi Phil,
>
> Looks good.
>
> Jennifer
>
> On 8/12/15 2:01 PM, Phil Race wrote:
>> Hi all,
>>
>> Still looking for any reviewers for this 7 day old review ...
>>
>> -phil.
>>
>> On 8/5/15 12:15 PM, Phil Race wrote:
>>> https://bugs.openjdk.java.net/browse/JDK-8132850
>>> http://cr.openjdk.java.net/~prr/8132850/
>>>
>>> The bug is an ArrayIndexOutofBoundsException when a very large set 
>>> of fonts are installed on Linux.
>>> It occurred rendering from a compositefont :
>>>
>>> Exception in thread "AWT-EventQueue-0" 
>>> java.lang.ArrayIndexOutOfBoundsException: -35127285
>>>     at 
>>> sun.font.FileFontStrike.setCachedGlyphPtr(FileFontStrike.java:520)
>>>     at 
>>> sun.font.FileFontStrike.setCachedGlyphPtr(FileFontStrike.java:537)
>>>     at 
>>> sun.font.FileFontStrike.getSlot0GlyphImagePtrs(FileFontStrike.java:449)
>>>     at 
>>> sun.font.CompositeStrike.getGlyphImagePtrs(CompositeStrike.java:115)
>>>     at sun.font.GlyphList.mapChars(GlyphList.java:272)
>>>
>>> Note that you do not see the exception on JDK 9 because it is caught 
>>> as a  result of
>>> some other work, but it is seen on 8, and the underlying problems 
>>> affect all releases.
>>>
>>> There are several contributing problems :
>>>
>>> - the native fontconfig code to accumulate the fonts was resetting 
>>> the set of glyphs for each time through the loop.
>>>  thus its heuristic to limit the number of slots was never met and 
>>> so it would add more slots than it should.
>>>  In addition it should limit to 256 (or fewer) anyway.
>>>
>>> - a special case in FileFontStrike accepted a composite glyph id. 
>>> These use the MS byte of the int to store
>>> a slot. Once it was > 127 then the test to see if the glyph was a 
>>> slot zero glyph failed. Hence the AIIOB.
>>>
>>> - finally for extra safety the CompositeFont constructor should 
>>> ignore trailing slots that will not fit.
>>>
>>> I could not devise a regression test since its requires a custom 
>>> system config
>>> and in any case the exception is not seen on 9 as noted above.
>>>
>>> -phil.
>>
>


-- 
Best regards, Sergey.

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