Hi Ed,

Any thoughts on the questions below?

Best regards,
Marcin

pon., 20 kwi 2020 o 16:21 Marcin Wojtas <m...@semihalf.com> napisał(a):
>
> Hi Ed,
>
> pt., 17 kwi 2020 o 15:52 Ed Maste <ema...@freebsd.org> napisał(a):
> >
> > On Fri, 17 Apr 2020 at 08:58, Marcin Wojtas <m...@semihalf.com> wrote:
> > >
> > > Hi,
> > >
> > > Together with our customers, Semihalf is interested in improving the 
> > > status
> > > of security mitigations enablement in FreeBSD.
> >
> > Happy to hear that there's interest in this work!
> >
> > > 1. Are there any hard blockers, like missing features or bugs, that 
> > > prevent
> > > enabling ASLR by default in the kernel and building the base system with
> > > -DWITH_PIE?
> >
> > I believe there are no showstopper issues but there are a some
> > prerequisites. One is that there are some applications that may
> > misbehave with randomization enabled. They would need to be
> > identified, and tagged (with the elfctl tool now in the base system).
>
> I was thinking if it is possible to come up with such wide test
> coverage to test every single application from the base system. Do you
> think it is achievable or should we rather follow the approach to do
> as many tests as possible, but rely on the community feedback to catch
> the corner cases (like the ntpd issue mentioned in this thread)?
> What about the ports?
>
> >
> > > 2. In case the enablement becomes eventually approved, will it be better 
> > > to
> > > do it for all archs or focus only on the selected ones?
> >
> > There's a general and increasing preference of avoiding different
> > defaults per architecture. One issue though is that some options may
> > have much larger performance impacts on certain architectures - e.g.
> > position independent executables (PIE) on i386.
>
> Understood. If there is likely a performance trade-off, how about
> doing tests e.g. on i386 and armv7? In case of a big drop or other
> issues, could limiting ALSR/PIE to 64-bit-only be a considered
> solution?
>
> >
> > > 3. IMO it may be worth to benchmark/stress the system for the stability
> > > verification and perf comparison purpose. Do you think it may be 
> > > reasonable
> > > to create a kind of reference matrix (archs vs tests)? Those could be done
> > > to evaluate the current state of the OS, but also for validating each
> > > proposed feature. I also think engaging the FreeBSD CI might be a huge 
> > > help
> > > in such an effort. BTW, any particular tests / benchmarks come to your 
> > > mind
> > > as useful in this case?
> >
> > Yes, benchmarking and testing are very important tasks on a path to
> > enabling these by default. I agree with the CI comment; we should
> > start with CI build + kyua runs with options turned on, in advance of
> > changing the default.
>
> Indeed I thought of kyua and measuring buildworld execution time for
> stressing the DUT and having the first comparison numbers for the low
> price.
>
> Do you think it is possible to get help here, i.e. is there a FreeBSD
> devops team, maintaining the Jenkins CI whose spare cycles could be
> used for this purpose? Or is this a field requiring external help from
> interested parties?
>
> Even before the automation, would it be useful to perform some runs on
> chosen archs?
>
> >
> > I would be interested in seeing macro-level benchmarking with
> > mitigations on/off - for example, I assume Firefox must have a
> > performance test suite that they use for tracking their own
> > performance changes during development, and we could use benchmarks
> > like that to see the impact of mitigations. Coming up with a full set
> > of appropriate benchmarks will be a useful endeavour.
>
> Yes, making use of something actively maintained would be great. Do
> you see a need for IO stressing/benchmarking for the discussed cases?
>
> Best regards,
> Marcin
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