Re: [CFT] ASLR and PIE on amd64

On 4/2/14, Oliver Pinter <oliver.pntr_at_gmail.com> wrote:
> On 3/31/14, Shawn Webb <lattera_at_gmail.com> wrote:
>> On Mar 31, 2014 02:07 AM +0200, Oliver Pinter wrote:
>>> On 3/22/14, Shawn Webb <lattera_at_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).