Am 09.01.2015 um 00:35 schrieb drago01:
On Fri, Jan 9, 2015 at 12:16 AM, Dennis Gilmore <dennis@xxxxxxxx> wrote:On Thu, 08 Jan 2015 20:25:36 +0100 Reindl Harald <h.reindl@xxxxxxxxxxxxx> 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 noticeableall 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 armThe 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
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