Intel processors are dead, so I have an AMD question

Post Reply New Topic

List: openbsd-misc
Subject: Intel Core 2
From: Theo de Raadt <deraadt () cvs ! openbsd ! org>
Date: 2007-06-27 17:08:16
Message-ID: 200706271708.l5RH8GkK024621 () cvs ! openbsd ! org
[Download message RAW]

Various developers are busy implimenting workarounds for serious bugs
in Intel's Core 2 cpu.

These processors are buggy as hell, and some of these bugs don't just
cause development/debugging problems, but will *ASSUREDLY* be
exploitable from userland code.

As is typical, BIOS vendors will be very late providing workarounds /
fixes for these processors bugs. Some bugs are unfixable and cannot
be worked around. Intel only provides detailed fixes to BIOS vendors
and large operating system groups. Open Source operating systems are
largely left in the cold.

Full (current) errata from Intel:

http://download.intel.com/design/proces ... 327914.pdf

- We bet there are many more errata not yet announced -- every month
this file gets larger.
- Intel understates the impact of these erraata very significantly.
Almost all operating systems will run into these bugs.
- Basically the MMU simply does not operate as specified/implimented
in previous generations of x86 hardware. It is not just buggy, but
Intel has gone further and defined "new ways to handle page tables"
(see page 58).
- Some of these bugs are along the lines of "buffer overflow"; where
a write-protect or non-execute bit for a page table entry is ignored.
Others are floating point instruction non-coherencies, or memory
corruptions -- outside of the range of permitted writing for the
process -- running common instruction sequences.
- All of this is just unbelievable to many of us.

An easier summary document for some people to read:

http://www.geek.com/images/geeknews/200 ... __full.gif

Note that some errata like AI65, AI79, AI43, AI39, AI90, AI99 scare
the hell out of us. Some of these are things that cannot be fixed in
running code, and some are things that every operating system will do
until about mid-2008, because that is how the MMU has always been
managed on all generations of Intel/AMD/whoeverelse hardware. Now
Intel is telling people to manage the MMU's TLB flushes in a new and
different way. Yet even if we do so, some of the errata listed are
unaffected by doing so.

As I said before, hiding in this list are 20-30 bugs that cannot be
worked around by operating systems, and will be potentially
exploitable. I would bet a lot of money that at least 2-3 of them
are.

For instance, AI90 is exploitable on some operating systems (but not
OpenBSD running default binaries).

At this time, I cannot recommend purchase of any machines based on the
Intel Core 2 until these issues are dealt with (which I suspect will
take more than a year). Intel must be come more transparent.

(While here, I would like to say that AMD is becoming less helpful day
by day towards open source operating systems too, perhaps because
their serious errata lists are growing rapidly too).

Without zero chance that there could have been a china teapot in orbit, no burden of proof would have been required because a valid proof could not possibly exist.

Well, yes. However, the Russel's teapot principle is not about the comparison of the chances. It's about the burden of proof.

It sounds like you had a freshman logic course and flunked it.

You're too predictable. Try harder.

The stupidest thing about your argument is that Russell's Teapot analogy has absolutely no applicability to the question of whether AMD's processors might be vulnerable to Meltdown.

Well, it seems that you're just beyond redemption. Good luck.

It's one thing to say "Russell's Teapot" as if they are some kind of magic words. It's another thing to show that the argument actually applies in any given situation.

It applies to every single situation where you say that something exists or may exist without any proofs. And, as I said, good luck. Go read some good rational thinking book.

No, it doesn't.

Go read the freaking book. Stop wasting my time.

You don't have the foggiest idea of what you are talking about. Your understanding of logic is clearly very poor. You don't understand the analogy and so you use it wrongly.

AMD doesn't claim that their CPUs are not vulnerable to Meltdown, but you do. Why is that, do you suppose? Do you know something AMD doesn't? Or do you just not have the logical capacity to understand what they are saying.

They say that they don't believe that their CPUs are vulnerable -- they clearly cannot prove that or they would have stated it in stronger terms like those they use for their GPUs which they unequivocally say are not effected by Meltdown. They would love to be able to claim that they aren't affected, but cannot.

If you can learn anything from this, your time is not being wasted. if you cannot learn from it, then you should go back to playing video games.

How about you kokopelli and Xenomind go to this link and download Inspectre and see for yourself. It's free.

https://www.grc.com/inspectre.htm

The results from this tell me that on my 4th Gen Intel processor, it's protected from Meltdown but not Spectre and all I'm waiting for is the firmware update on the motherboard and the CPU for Spectre.

For some of us the link is rather useless -- you have to use Microsoft Windows for the link to work.

Also, while AMD processors are believed to not be vulnerable to Meltdown, it cannot be ruled out completely at this point in time. We cannot say that all variants of Meltdown have been discovered.