Am 09.01.2015 um 00:35 schrieb drago01:
On Fri, Jan 9, 2015 at 12:16 AM, Dennis Gilmore
<dennis(a)ausil.us> wrote:
> On Thu, 08 Jan 2015 20:25:36 +0100
> Reindl Harald <h.reindl(a)thelounge.net> wrote:
>>
>> Am 08.01.2015 um 19:45 schrieb Miloslav Trmač:
>>>> = Proposed System Wide Change: Harden all packages with
>>>> position-independent code =
>>>>
>>>> Harden all packages with position-independent code to limit the
>>>> damage from certain security vulnerabilities.
>>>
>>> So this proposal is for _all_ architectures, including the
>>> register-starved 32-bit i?86 where the overhead is, IIRC, around
>>> 10%. I am by now quite convinced that x86_64 should be using PIE
>>> by default. As for 32-bit, I’m torn between “this is too much
>>> overhead” and “32-bit isn’t worth the worry, let’s instead make the
>>> defaults consistent.”
>>
>> probably not worth the worry, new machines are x86_64 mostly, keep in
>> mind RHEL7 dropped i686 at all
>>
>> even if they are still used - 10% sounds much *but* such old machines
>> mostly have a special task and are far away from noticeable load and
>> it really depends on the workload if you even notice 20% performance
>> drop
>>
>> at least i doubt there is a noticeable userbase with i686 running
>> Fedora at all *and* would notice the drop noticeable
>
> all of the OLPC XO 1.0 and 1.5 devices are running i686 fedora, that
> userbase is in the millions, but would they notice the performance
> drop I do not know.
>
> It would be interesting to see how performance was impacted on 32 bit
> arm
The address space on 32 bit is relatively small so randomization does
not gain much in terms of security anyway (you could bruteforce the
addresses in a reasonable amount of time).
So high cost low benefit
don't ignore the maintainance costs for handle i686 different, take that
into account (including bugreports with different build-flags) the
benefit may be higher and the main question is still: how much is the
*feelable and real* impact for the user in case of normal operations
besides benchmarks