Date: Thu, 17 Jul 2014 18:54:06 -0500 From: Bryan Drewery <bdrewery@FreeBSD.org> To: freebsd-arch@freebsd.org Cc: PaX Team <pageexec@freemail.hu>, alc@rice.edu, Oliver Pinter <oliver.pntr@gmail.com>, des@freebsd.org, Shawn Webb <lattera@gmail.com> Subject: Re: [RFC] ASLR Whitepaper and Candidate Final Patch Message-ID: <53C8621E.5040101@FreeBSD.org> In-Reply-To: <20140711232914.GH41807@pwnie.vrt.sourcefire.com> References: <20140711232914.GH41807@pwnie.vrt.sourcefire.com>
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On 7/11/14, 6:29 PM, Shawn Webb wrote: > Hey All, > > Oliver Pinter and I have been working hard on our ASLR implementation. > We're now in the final stages of development and would like to get > feedback from the community. I've attached to this email a small > whitepaper that details our implementation and the accompanying patch. > > There is one part of the patch that I wrote that is quite an ugly hack > and would like to get some feedback on. I added a little hack to > sys_mmap() to apply ASLR to calls to mmap(2) when MAP_32BIT is > specified. I'd like to remove that ugly hack to something a bit more > beautiful, so if anyone has any suggestions, I'm all ears. > > Other than that ugly hack, the code adheres to FreeBSD's style(9) > standards. I believe we have an awesome implementation, one I've > personally been using without issue for months. > > I'm looking forward to your comments and questions. I've CC'd the PaX > team. Please keep them CC'd in your replies. > > Thank you very much, > > Shawn Webb > CC: PaX Team > CC: Oliver Pinter > CC: des@freebsd.org > CC: alc@rice.edu > CC: bdrewery@freebsd.org > > PS - Sorry for the duplicate emails. I hit the wrong key and didn't CC > everyone. I plan to review and test this and then commit it likely next weekend (7/27). I would do it sooner but will be busy next week. One big shortcoming I reported to Shawn was lack of committable documentation. He is working on that now. There was a lot of outrage over the NO_PIE commit which seemed to be much more directed at ASLR and its support scope across the system than the simple -fPIE change that was committed. If anyone has any concerns please do speak up now with constructive input. I am leaning towards leaving by PIE/ASLR off by default on head until more widespread testing can be done. Eventually we will want it enabled by default though. -- Regards, Bryan Drewery
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