[coreboot] T450S + Coreboot

Thu Aug 30 15:51:51 CEST 2018

Hi Youness,

> The fact that it's closed source and not user-controlled (Even if you had
> the sources, you can't modify them and update it to your custom ME
> version) is where the problem actually is. There *might* be a backdoor
> hidden somewhere in there, or maybe there isn't, nobody knows.

I agree with your statement above. But, please look on this question
from the end user's perspective, who might be not a software
developer. Imagine that you have a choice between two
similar-by-performance coreboot-supported laptops: according to
cpubenchmark's passmark, Lenovo G505S's AMD A10-5750M = 3342 points
(from 886 samples) while Librem 15's Intel i7-6500U = 4429 points
(from 3345 samples), so the CPU performance difference is just 1/3 (
and at the fresh test results there might be little to none, since the
Intel-only Meltdown vulnerability requires a patch which eats up to
30% performance depending on the workload, and there are also some
other Intel-specific "performance-eating" vulnerabilities, the most
serious of which - TLBleed / T1TF - may soon require the disabling of
HyperThreading at all the Intel CPUs, see [1] and [2] )

The essential power user features like 16GB RAM support and Xen-level
hardware virtualization technologies ( IOMMU / AMD-V RVI / NPT/SLAT )
- are also well supported by G505S. But, one laptop has a creepy
management engine (could be creepy enough to a user who didn't study
the tons of Intel documentation) where there *might* be a backdoor, is
not user-controlled (currently) and has a closed-source firmware
(currently). While another laptop does not contain any hardware
management engine at all, neither ME nor PSP. Which laptop you would
have chosen - as a user, not as an employee of Purism - company which
for some unknown-to-me-reasons is hard-tied to Intel CPUs? Even if we
wouldn't be considering the significant price difference between G505S
and Librem 15 - which more than compensates the possible performance
advantage (if it would still exist after patching those Intel-specific
vulnerabilities) as well as lack of some nice features like
kill-switches (unless a user would DIY them), at least to me the
choice is obvious:

no management engine = one less potential problem, one less headache
to deal with...

> Your comparison of saying the ME is a backdoor is like saying that a
> webcam is a spying device because it can capture images of you! [...]
> The fact that the webcam schematics isn't open means that it could
> still have a small wifi or GSM chip embedded inside

Yes, but I could easily put a tape over that webcam, disconnect and
remove a webcam module from the laptop's case (or even make a custom
DIY kill-switch). Same for a microphone - could be easily desoldered
(and maybe soldered back but through a kill-switch). And for the
speakers: according to the recent researches the speakers could act as
a microphone - see [3] - so Librem 15 should have a kill-switch for
the speakers as well. Meanwhile you can't throw away ME the same easy
way.

> you yourself said earlier, when talking about the AtomBIOS
> that "it could be disassembled quite well with AtomDis -
> https://github.com/mikebdp2/AtomDis - reducing any security concerns
> regarding this blob to a minimum.", well, the ME can be disassembled
> with any x86 disassembler, so why can't you also say that "reduces any
> security concerns regarding the ME to a minimum".

Actually this AtomBIOS blob is not required to run this laptop, only
to initialize its' display. It is possible to turn this laptop into a
miniPC/server and still use its' hardware without this blob, although
it wouldn't be exactly a laptop after that. But if we would consider
this blob as required: here is a quality of disassembly I'm getting
with AtomDis - https://pastebin.com/xKW9FV58 . All the command tables
and data tables are named and in many cases it could be understood
what some particular piece of code is doing even after a quick glance.
Are you sure that your ME blob x86 disassembly is providing a similar
or higher level of transparency? Perhaps it is this level of
transparency which allowed to 95% complete the development of the
opensource AtomBIOS alternative called OpenAtom ( I think the
development efforts have stopped partially because no-one have noticed
any backdoors after completing the 95% and it became much less
interesting to complete the remaining 5% , [4] )

> We're about to get full control back of the ME. I've been working for
> the past few weeks on reproducing the PTResearch buffer overflow
> exploit on the ME, and yesterday they released a PoC for Apollolake
> (in case you missed it : https://github.com/ptresearch/IntelTXE-PoC),
> so with the progress I made and with that, I should be able to soon
> port it to skylake (and write docs on how to port to other platforms
> as well) which will at least give us the ability to gain back the
> 'user-controlled' aspect of it as we'd have code execution on it.

Indeed, the things might change if you will find a way to get full
control back of the ME. If you will discover a way to completely
"unlock" it and run your own code on it, this Intel Quark CPU core (on
which Librem 15 Skylake's ME is based) could be really useful - and
not necessarily for the remote management purposes, perhaps there are
infinite possibilities of what you could do with this core. So it
could be turned into the competitive advantage which will be valid
even from a paranoid point of view. It will be really nice to see it
happen. But it didn't happen yet - and I am worried that Intel's
hostile actions might prevent the completion of your benevolent
research or at least prevent it from going public. Because I remember
how they took down your "FSP Reverse Engineering" articles as well as
the source code associated with it. What will prevent them from doing
it again? And if they can't DMCA your work because the reverse
engineering is legal at many countries including USA, they could just
threaten to stop supplying Librem laptops with their CPUs (like they
probably did) and it's all over now.

Actually it might be a good idea for Purism to at least consider the
switch to AMD Ryzen CPUs. Yes, unlike the 15h/early16h gen AMD CPUs,
their new Ryzen CPUs contain the PSP, Platform Security Processor -
which is also a management engine. But it is significantly younger
than Intel ME (Skylake's ME is already generation 11), so PSP should
have less sophisticated protections and it should be easier to
"jailbreak" this "young PSP" rather than "modern ME". Early ME
implementations were also weak, after all, and I expect "young PSP" to
be weak also. Also, those AMD CPUs do not suffer from the
recently-discovered Intel-specific vulnerabilities and their
performance-degrading patches will not be required. Finally, AMD had a
good collaboration history with coreboot (although this collaboration
is not active currently, it might be renewed if there will be enough
mutual interest) - and I believe AMD at least will not be as hostile
towards your opensource/reverse-engineering efforts as Intel is
currently. If any of these statements seems reasonable to you, please
think of trying to make your Purism company to at least consider this
AMD switch.

Best regards,
Mike

"disable Intel hyperthreading" :
[1] - https://news.ycombinator.com/item?id=17829790
[2] - https://marc.info/?l=openbsd-tech&m=153504937925732&w=2
speaker as a microphone:
[3] - https://security.stackexchange.com/questions/154343/can-a-speaker-be-used-as-a-microphone
[4] - https://mail.coreboot.org/pipermail/coreboot/2018-January/085979.html
On Thu, Aug 30, 2018 at 12:41 AM Youness Alaoui
<kakaroto at kakaroto.homelinux.net> wrote:
>
>  Wow, Mike, seriously, I am going to side 100% with Nico, you are
> spreading FUD, making your own personal opinions (which are themselves
> derived from other people's FUD) and stating them as the universal
> law.
> The ME is not known to be a backdoor. It doesn't mean that it's not a
> backdoor, it simply means that it's not known to be a backdoor. The
> fact that it's closed source and not user-controlled (Even if you had
> the sources, you can't modify them and update it to your custom ME
> version) is where the problem actually is. There *might* be a backdoor
> hidden somewhere in there, or maybe there isn't, nobody knows, but
> there has been a lot of research done on the ME and so far, none have
> been found as far as I know.
>
> Your worry about what the ME does, how it can give someone control
> over the PC, etc.. are NOT what qualifies it as a "backdoor", but like
> Nico said, it's a frontdoor, it's not a "hidden access", it's a
> "promoted access" to the PC, it's the main ME functionality which is
> well documented. You don't have to use some "only known to some secret
> person" trick to access the ME, you just need to point your web
> browser to the right port on localhost.
> Your comparison of saying the ME is a backdoor is like saying that a
> webcam is a spying device because it can capture images of you! Yeah,
> sure, that's technically true, it can capture images of you, but only
> after you plug it in and open an image capture software, and you still
> have control of those images. The fact that the webcam schematics
> isn't open means that it could still have a small wifi or GSM chip
> embedded inside which makes it send the images to the CIA, but it's
> not a guarantee that it does. So, yes, you can complain that the
> webcam isn't open hardware so you can't technically trust what it
> does, but you can't just come out and say with absolute certainty that
> any and all webcams in the world are spying devices for the CIA,
> that's just ridiculous.
>
> So, back to the ME, we know exactly what it does, it's all extremely
> well documented and explained, the fact that it allows remote control
> of the PC is actually the reason for its existence and it's a very
> very valid reason in the corporate context and the fact that those
> features also 'coincidentally' resemble the features of an actual
> 'trojan horse' virus, doesn't mean that the ME itself is a virus..
> otherwise the 'rm' linux command would be considered a virus since it
> deletes files and there are some viruses that can delete your files as
> well....
> Now the problem is that it's closed source, and not user controlled
> (remote control features *are* user controlled, I'm talking about
> being able to replace the firmware with your own), so yes, it can't be
> audited by the larger open source community, but that also doesn't
> guarantee any security necessarily (how many open source programs
> still have security bugs?).
>
> Either way, you yourself said earlier, when talking about the AtomBIOS
> that "it could be disassembled quite well with AtomDis -
> https://github.com/mikebdp2/AtomDis - reducing any security concerns
> regarding this blob to a minimum.", well, the ME can be disassembled
> with any x86 disassembler, so why can't you also say that "reduces any
> security concerns regarding the ME to a minimum".
>
> We're about to get full control back of the ME. I've been working for
> the past few weeks on reproducing the PTResearch buffer overflow
> exploit on the ME, and yesterday they released a PoC for Apollolake
> (in case you missed it : https://github.com/ptresearch/IntelTXE-PoC),
> so with the progress I made and with that, I should be able to soon
> port it to skylake (and write docs on how to port to other platforms
> as well) which will at least give us the ability to gain back the
> 'user-controlled' aspect of it as we'd have code execution on it.
> Which by the way, also means that BootGuard can be disabled (since the
> ME is the one checking for the boot guard signatures), which should
> enable the ability to port coreboot to a lot more machines (including
> the T450S that this thread is supposed to be about). Hopefully....
>
> On Wed, Aug 29, 2018 at 5:50 AM Mike Banon <mikebdp2 at gmail.com> wrote:
> >
> > > What suspicious activities? I know, for many people the Intel ME firmware
> > > contains unwanted features. But these features are documented.
> > > In your world, a device becomes backdoored because somebody
> > > didn't read the manual?!?
> >
> > Somewhere I've seen a report about Intel ME suspicious network
> > activities (if I remember correctly they were using Wireshark on a PC
> > placed between a computer with ME and the outside network) which has
> > affected my personal opinion. Although it could be argued that its
> > just some OEM has set up their ME in such a way, maybe even in a
> > documented way (although a way undesirable to the end user), still it
> > didn't look good to me. In addition, regarding all those Intel ME
> > vulnerabilities recently discovered: one could assume that at least
> > some of these "vulnerabilities" @ were actually the backdoors which
> > have been patched just because they have been discovered by someone
> > else than the american intelligence agencies who always knew them @ .
> > Now Intel has patched these "vulnerabilities", but we do not know if
> > some other "vulnerabilities" have been left unnoticed by the outsiders
> > or if some new "vulnerabilities" have been added. And we the open
> > source enthusiasts can't even verify that personally, because the
> > source code of Intel ME firmware is closed. I cannot understand, how
> > such a high level professional open source developer as you, Nico,
> > finds it okay to just trust Intel ME despite its' deeply proprietary
> > nature. Management engine with a closed source proprietary firmware -
> > it even sounds awful..... I totally agree with Richard Stallman when
> > he calls Intel ME a backdoor - https://stallman.org/intel.html
> >
> > > Please read [1] and [2] very carefully, I hope even you will spot
> > > technical differences. [...] You cannot just take somebody's words
> > > and give them a different meaning just because somebody else used
> > > them in a different context. [...] You did it again, btw., stating something
> > > (definition of frontdoor) and making it look like the generally accepted definition.
> >
> > Before receiving your message I knew only one definition of a
> > "frontdoor" computing term which I described in my previous message.
> > Although I don't know which definition is more popular, sorry for
> > misunderstanding you.
> >
> > Mike
> >
> >
> > On Wed, Aug 29, 2018 at 12:24 AM Nico Huber <nico.h at gmx.de> wrote:
> > >
> > > *sigh*,
> > >
> > > On 28.08.2018 22:00, Mike Banon wrote:
> > > > You are right, my choice of words has been far from ideal. I apologize
> > > > for that. However, to be confident that Intel ME is a backdoor
> > > > (personal opinion) - one does not have to be its' creator.
> > >
> > > sorry I meant the creator of us (God) not the ME. I doubt the creator
> > > of the ME knows everybody's opinion either. Which is what I was talking
> > > about. A good practice is to quote and answer below that quote, this way
> > > you can easily check if what you write makes sense in the given context.
> > >
> > > > I think
> > > > there are enough documents describing its' functionality and enough
> > > > evidence gathered by the independent security researchers about the
> > > > suspicious activities of this hardware module. If it looks like a
> > > > duck, swims like a duck, and quacks like a duck, then it probably is a
> > > > duck?
> > >
> > > WTF again? what suspicious activities? I know, for many people the ME
> > > firmware contains unwanted features. But these features are documented.
> > > In your world, a device becomes backdoored because somebody didn't read
> > > the manual?!?
> > >
> > > > There are no technical differences between the 'backdoor', and
> > > > 'frontdoor'.
> > >
> > > Please read [1] and [2] very carefully, I hope even you will spot tech-
> > > nical differences.
> > >
> > > > Like a 'conspiracy theorist', 'frontdoor' is a term
> > > > coming from the american 3-letter-agencies. 'Frontdoor' is their term
> > > > for a 'backdoor' to which only they (currently) have an access. This
> > > > article summarizes it well:
> > > > https://www.justsecurity.org/16503/security-front-doors-vs-back-doors-distinction-difference/
> > > > . 'Backdoor' term has a negative reputation, so they would like to
> > > > push this 'frontdoor' term forward.
> > >
> > > This is very infantile. You cannot just take somebody's words and give
> > > them a different meaning just because somebody else used them in a dif-
> > > ferent context. When I say frontdoor, I mean a door at a front where
> > > everyone can see it. A backdoor implies something hidden, the ME fea-
> > > tures were never hidden (AFAIK, a stupid OEM may prove me wrong, but I
> > > don't know any instance).
> > >
> > > You did it again, btw., stating something (definition of frontdoor) and
> > > making it look like the generally accepted definition.
> > >
> > > Nico
> > >
> > > [1] https://en.wiktionary.org/wiki/back_door
> > > [2] https://en.wiktionary.org/wiki/front_door