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Re: [ft-devel] details on iPhone exploit caused by FreeType?

From: Werner LEMBERG
Subject: Re: [ft-devel] details on iPhone exploit caused by FreeType?
Date: Sat, 09 Jul 2011 06:53:05 +0200 (CEST)

> I would have this check under default: on line 1013 because other
> cases have good checks already.

But the `default' label continues, while `Unexpected_OtherSubr'

> That default is rather strange: "wish me luck".  Really?

:-)  Obviously, you aren't aware of TeX's warning messages like

  I've inserted a begin-math/end-math symbol since I think you left
  one out.  Proceed, with fingers crossed.

If you process the PDF used as the iPhone exploit with acroread, you
actually get a visible result inspite of the buggy font!  In other
words, acroread is extremely fault-tolerant.  However, it's luck IMHO
whether the PS font engine can continue or not.

Ideally, FreeType's PS engine should try to be fault-tolerant too.
For example, in case of negative arguments to `callothersubr' it is
possible to simply ignore the opcode and its two arguments.  For the
moment, I've decided to abort.  Patches to improve this are highly


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