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Date: Sun, 26 Oct 2014 18:35:59 -0700
From: Michal Zalewski <lcamtuf@...edump.cx>
To: oss-security <oss-security@...ts.openwall.com>
Subject: Re: Re: strings / libbfd crasher

> I don't know whether it's the same crash or not but I've dug results of my
> older experiments with zzuf. Attached are two crasher for `objdump -x` --
> one pe and one elf. elf also crashes `strings`. Sorry, not researched.

objdump-elf-crasher looks like a stack exhaustion with
/usr/bin/strings, so probably not a big deal.

objdump-pe-crasher doesn't affect strings, but if you do run objdump
-x, it looks like an attempt to do fprintf() with a bogus pointer,
called from pe_print_edata(). Specifically, there's a line that goes
like this:

  fprintf (file,
           " %s\n", data + edt.name - adj);

...and edt.name, looks like, comes from:

  edt.name           = bfd_get_32 (abfd, data + 12);

...and the value is completely off-charts. So, probably another
instance of essentially no range checking, although this particular
crash may be not exploitable at a very quick glance, unless something
interesting happened beforehand.

/mz

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