Date: Wed, 9 Apr 2014 02:17:48 +0200 From: Oliver Pinter <oliver.pntr@gmail.com> To: FreeBSD-current <freebsd-current@freebsd.org> Cc: Shawn Webb <lattera@gmail.com> Subject: Re: [CFT] ASLR and PIE on amd64 Message-ID: <CAPjTQNEv1m5vznFnJPg5njcX%2BQ2c1N6Xv%2BjfmGYUUqboFg_OFg@mail.gmail.com> In-Reply-To: <20140402152232.GF20907@pwnie.vrt.sourcefire.com> References: <CADt0fhzxTF=CoRZSLXv3MpKJisZx1kCd48O3wqkSL-8vL3ogaA@mail.gmail.com> <CAPjTQNFe7mrBCWNqWiJPPW7kkE9RyhEH-3XqvVkqDzb%2B-YrZkg@mail.gmail.com> <20140331002436.GB14025@pwnie.vrt.sourcefire.com> <CAPjTQNH1x7UYVrV60QpaE3-q%2BJ%2B5OXRnNxhN=_UYpua-VJWvUA@mail.gmail.com> <CAPjTQNEJh6xqOLC0gCZV2zjtqaJtw9%2Brxfg5jW6XJiVSVxWaEA@mail.gmail.com> <20140402152232.GF20907@pwnie.vrt.sourcefire.com>
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On 4/2/14, Shawn Webb <lattera@gmail.com> wrote: > On Apr 02, 2014 04:54 PM +0200, Oliver Pinter wrote: >> On 4/2/14, Oliver Pinter <oliver.pntr@gmail.com> wrote: >> > On 3/31/14, Shawn Webb <lattera@gmail.com> wrote: >> >> On Mar 31, 2014 02:07 AM +0200, Oliver Pinter wrote: >> >>> On 3/22/14, Shawn Webb <lattera@gmail.com> wrote: >> >>> > Hey All, >> >>> > >> >>> > First off, I hope that even as a non-committer, it's okay that I >> >>> > post >> >>> > a call for testing. If not, please excuse my newbishness in this >> >>> > process. This is my first time submitting a major patch upstream to >> >>> > FreeBSD. >> >>> > >> >>> > Over the past few months, I've had the opportunity and pleasure to >> >>> > enhance existing patches to FreeBSD that implement a common exploit >> >>> > mitigation technology called Address Space Layout Randomization >> >>> > (ASLR) >> >>> > along with support for Position Independent Executables (PIE). >> >>> > ASLR+PIE has been a long-requested feature by many people I've met >> >>> > on >> >>> > IRC. >> >>> > >> >>> > I've submitted my patch to PR kernel/181497. I'm currently in the >> >>> > process of adding PIE support to certain high-visibility >> >>> > applications >> >>> > in base (mainly network daemons). I've added a make.conf knob >> >>> > that's >> >>> > default to enabled (WITH_PIE=1). An application has to also >> >>> > explicitly >> >>> > support PIE as well by defining CAN_PIE in the Makefile prior to >> >>> > including bsd.prog.mk. After I get a decent amount of applications >> >>> > enabled with PIE support, I'll submit one last patch. >> >>> > >> >>> > The following sysctl's can be set with a kernel compiled with the >> >>> > PAX_ASLR option: >> >>> > >> >>> > security.pax.aslr.status: 1 >> >>> > security.pax.aslr.debug: 0 >> >>> > security.pax.aslr.mmap_len: 16 >> >>> > security.pax.aslr.stack_len: 12 >> >>> > security.pax.aslr.exec_len: 12 >> >>> > >> >>> > The security.pax.aslr.status sysctl enables and disables the ASLR >> >>> > system as a whole. The debug sysctl gives debugging output. The >> >>> > mmap_len sysctl tells the ASLR system how many bits to randomize >> >>> > with >> >>> > mmap() is called. The stack_len sysctl tells the ASLR system how >> >>> > many >> >>> > bits to randomize in the stack. The exec_len sysctl tells the ASLR >> >>> > system how many bits to randomize the execbase (this controls PIE). >> >>> > These sysctls can be set as a per-jail basis. If you have an >> >>> > application which doesn't support ASLR, yet you want ASLR enabled >> >>> > for >> >>> > everything else, you can simply place that misbehaving application >> >>> > in >> >>> > a jail with only that jail's ASLR settings turned off. >> >>> > >> >>> > Please let me know how your testing goes. I'm giving a presentation >> >>> > at >> >>> > BSDCan regarding this. >> >>> > >> >>> > If you want to keep tabs on my bleeding-edge development process, >> >>> > please follow my progress on GitHub: >> >>> > https://github.com/lattera/freebsd (branch: soldierx/lattera/aslr). >> >>> > >> >>> > Thank you very much, >> >>> >> >>> Hi! >> >>> >> >>> Please apply this patch. This fixed an issue with tunables. >> >> >> >> Patch merged successfully into my GitHub repo. Fixed with commit >> >> d2c0813. I'll include it in my next patch submission upstream when I >> >> submit my PIE work. Thanks! >> > >> > please see the attached patch, compile and boot tested on amd64 >> >> >> Some more patches, and one critical fix >> (0006-PAX-ASLR-use-the-right-sysent-before-this-commit-cal.patch). > > You are awesome. I'll integrate those patches today. In reviewing your > patches, I noticed a few places where I'm keying off the local > pax_aslr_debug variable. I ought to switch that to keying off the jail's > pr_pax_aslr_debug variable. > https://github.com/HardenedBSD/hardenedBSD/commits/hardened/10/aslr
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