[RFC] ASLR Whitepaper and Candidate Final Patch

[Shawn Webb]

On Jul 23, 2014 06:50 PM -0500, Pedro Giffuni wrote:
> 
> Il giorno 23/lug/2014, alle ore 18:44, Shawn Webb <lattera at gmail.com> ha scritto:
> 
> > On Jul 23, 2014 06:37 PM -0500, Pedro Giffuni wrote:
> >> Hi;
> >> 
> >> Il giorno 22/lug/2014, alle ore 19:45, Shawn Webb <lattera at gmail.com> ha scritto:
> >> 
> >>>>> ...
> >>>> 
> >>>> Hi Shawn:
> >>>> 
> >>>> Great news that this work is coming to fruition -- ASLR is long overdue.
> >>>> 
> >>>> Are you having any luck with performance measurements?  Unixbench seems like a 
> >>>> good starting point, but I wonder if it would be useful to look, in 
> >>>> particular, at memory-mapping intensive workloads that might be affected as a 
> >>>> result of changes in kernel VM data-structure use, or greater fragmentation of
> >>>> the address space.  I'm not sure I have a specific application here in mind -- 
> >>>> in the past I might have pointed out tools such as ElectricFence that tend to 
> >>>> increase fragmentation themselves.
> >>> 
> >>> The unixbench tests on that laptop have finished. However, I've been
> >>> fighting a pesky migraine these last couple days, so I haven't had the
> >>> opportunity to aggregate the results into a nice little spreadsheet. I'm
> >>> hoping to finish it up by the end of the week.
> >>> 
> >>> I'll take a look at ElectricFence this weekend. Additionally, I have a
> >>> netbook somewhere. Once I find it and its power cord, I'll install
> >>> FreeBSD/x86 and re-run the same tests on that.
> >>> 
> >> 
> >> Somewhat related to ElectricFence? will ASLR have an adverse effect on debuggers?
> >> 
> >> I googled around and got to this:
> >> 
> >> http://www.outflux.net/blog/archives/2010/07/03/gdb-turns-off-aslr/
> > 
> > I've been doing all my ClamAV development on my FreeBSD box with ASLR
> > enabled. Development tools like gdb and valgrind work great, even with
> > corefiles. I have not, however, tried lldb.
> > 
> 
> OK, but it?s worth to take a look if we need to support something to turn it off.
> Apparently gdb disables ASLR on MacOSX too:
> 
> http://reverse.put.as/2011/08/11/how-gdb-disables-aslr-in-mac-os-x-lion/

Completely agreed. It's easily possible my use case is different than
others'. The more eyes on this project and the more testers we have, the
better.

Thanks,

Shawn
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