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Meltdown Update Kernel doesnt boot

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Re: Meltdown Update Kernel doesnt boot

#161

Post by jijji »

andrewflnr wrote: post #116
Animats wrote: post #113

Earlier quoted context omitted.

The Intel Management Engine is a backdoor. Speed variations in speculative execution are an inherent property of the technology. Until recently, few people thought this was exploitable, and it took a lot of work to figure out how to exploit this.

You do realize those are ideal properties for a backdoor, don't you? If you were writing the spec for a dream backdoor, you would write that down. The only way you could improve it would be "everyone thinks it's impossible, and they never figure it out."

the ideal properties of a backdoor were visualized to me the day i hacked into an author of a largely distributed piece of smtp mail server, only to find sitting in his home directory an unpublished integer overflow exploit written by him years earlier for a version of the software that is currently in wide distribution...

Re: Meltdown Update Kernel doesnt boot

#162

Post by frik »

_Nat_ wrote: post #55
ask098 wrote: post #2

it's the fault of Intel, why don't they recall all the CPU? just like vehicle company

Are you suggesting that we recall the great bulk of modern CPU's? Like, literally gut everyone's computers, including those in data centers and running critical infrastructure, until replacements are eventually manufactured? Or did you mean something else?

> Are you suggesting that we recall the great bulk of modern CPU's? Like, literally gut everyone's computers

(not OP) but YES!

INTL had to recall their Pentium 1 too, but did so after a lot of pressure and mainly in US. Many Pentium 1 were still left unfixed because of INTL. All operating systems and BIOS needed a fix to correct the problem. Though back then internet wasn't mainstream, neither were OS updates, so many broken CPUs never run the fix but also never run a program that crashed the CPU with that bug.

INTL has to recall all Pentium Pro, Pentium 2, Pentium 3, Pentium M, Pentium 4, Pentium D, Core, Core 2 Duo, Core 2 Quad, Atom (2013+), i3/i5/i7 and the equivalent server Xeon counterparts.

Even if it means financial troubles for INTL, they fxcked up big time. Who knows how long this backdoor was known or who designed it.

The question is why are commentor here defending INTL?? Do you have stock, or are an employee or otherwise benefit from them and have a certain interest in their wellbeing??

Re: Meltdown Update Kernel doesnt boot

#163

Post by dvfjsdhgfv »

jijji wrote: post #161
andrewflnr wrote: post #116

Earlier quoted context omitted.

You do realize those are ideal properties for a backdoor, don't you? If you were writing the spec for a dream backdoor, you would write that down. The only way you could improve it would be "everyone thinks it's impossible, and they never figure it out."

the ideal properties of a backdoor were visualized to me the day i hacked into an author of a largely distributed piece of smtp mail server, only to find sitting in his home directory an unpublished integer overflow exploit written by him years earlier for a version of the software that is currently in wide distribution...

That's close to perfect, indeed. The drawbacks in this scenario are that (1) not everybody runs an SMTP server, (2) if it's open source (and if it's very popular, then it is), some other smart people will look for the bug and publish it for fame. That's quite different from a backdoor built into a processor (although I really doubt Intel was really involved in any shady practices, it looks like they were not smart enough).

Re: Meltdown Update Kernel doesnt boot

#164

Post by hvidgaard »

Zakharov wrote: post #146
brokenmachine wrote: post #74

Earlier quoted context omitted.

Not sure if Meltdown is the same, but I read that Spectre can recover memory at about 10kb/sec. So it wouldn't be very efficient to scan the entire memory for a known pattern. I suppose if there was an exploit targeted at a specific program, it would be possible to work out what location the secrets are stored in?

According to the paper, Meltdown can recover memory at about 500 kb/s

It's still "only" 1.7gb/hour. If programs follow reasonable security practices, it shouldn't be possible to stumble upon secrets in the memory. This underlines the importance of things such as ASLR and not holding your key in memory longer than needed and rotating them as well.

Re: Meltdown Update Kernel doesnt boot

#165

Post by PatchMonkey »

bArray wrote: post #47
gkya wrote: post #20

Would this entire Meltdown/Spectre thing count as the biggest mess-up of computing history? When yesterday the PoC repo was posted here, the spy.mp4 demo video gave me some chills. And now I can't update my OS before making an installation USB because Canonical can't just follow Linus' releases. Thanks.

>Would this entire Meltdown/Spectre thing count as the biggest mess-up of computing history? When yesterday the PoC repo was posted here, the spy.mp4 demo video gave me some chills. It must be up there amongst the greats, probably with the "halt and catch fire" op code. Normally they just patch this stuff with microcode and never really tell anybody, this time that won't work. I'm not entirely convinced it was a mist…

Those undocumented features & byte code? HAP mode - something the NSA doesnt want you to know exists, but that they had put into intelME from Skylake onward.

But yet and still we found out. So yes, this security through obscurity approach is terrible (with a code embargo being the obvious exception).

They only update microcode when they have to. When doing otherwise risks... Well, this kind of mess.

You dont wanna know how many times I've rebuilt my gentoo system chasing after retpoline kernel & gcc builds that just... Break everything.

It should be interesting to see how it all develops

Re: Meltdown Update Kernel doesnt boot

#166

Post by IceyEC »

snuxoll wrote: post #149
nykolasz wrote: post #130

Waiting a few days to patch my own servers... Not sure what is more dangerous right now: applying these rushed patches or the vuln itself.

What distro are you running? I trust Red Hat to get kernel updates right the first time, I just patched externally facing servers and systems that handle PHI tonight with no issues (outside of one of my PostgreSQL servers showing a non-neglible increase in CPU usage, damnit Intel). Of course, I also go into any updates with a rollback plan. ITIL sucks, but one thing it taught me was the value of well documented plans…

This seems like one of those things that is very hard to get right: https://forums.aws.amazon.com/thread.jspa?messageID=823033

Re: Meltdown Update Kernel doesnt boot

#167

Post by _0w8t »

eli_gottlieb wrote: post #131
Animats wrote: post #113

Earlier quoted context omitted.

The Intel Management Engine is a backdoor. Speed variations in speculative execution are an inherent property of the technology. Until recently, few people thought this was exploitable, and it took a lot of work to figure out how to exploit this.

If any quantity about what the processor does, outside the intended effect, has a different distribution when X happens versus Y, then the distribution of that quantity is exploitable. Period. Any nonuniform distribution in any quantity that is not part of the spec is exploitable!

It is only exploitable if one can measure the difference and extract useful information. Until Spectre guys discovered the double read technique, the expectation was that speculative execution did not allow to extract useful information besides extremely artificial theoretical cases.

Re: Meltdown Update Kernel doesnt boot

#168

Post by _0w8t »

hvidgaard wrote: post #164
Zakharov wrote: post #146

Earlier quoted context omitted.

According to the paper, Meltdown can recover memory at about 500 kb/s

It's still "only" 1.7gb/hour. If programs follow reasonable security practices, it shouldn't be possible to stumble upon secrets in the memory. This underlines the importance of things such as ASLR and not holding your key in memory longer than needed and rotating them as well.

Meltdown is fast enough to learn everything about layout of data structures in kernel or other programs and then use it to extract information from particular areas holding the keys.

Re: Meltdown Update Kernel doesnt boot

#169

Post by paulie_a »

dvfjsdhgfv wrote: post #163
jijji wrote: post #161

Earlier quoted context omitted.

the ideal properties of a backdoor were visualized to me the day i hacked into an author of a largely distributed piece of smtp mail server, only to find sitting in his home directory an unpublished integer overflow exploit written by him years earlier for a version of the software that is currently in wide distribution...

That's close to perfect, indeed. The drawbacks in this scenario are that (1) not everybody runs an SMTP server, (2) if it's open source (and if it's very popular, then it is), some other smart people will look for the bug and publish it for fame. That's quite different from a backdoor built into a processor (although I really doubt Intel was really involved in any shady practices, it looks like they were not smart en…

Judging from the numerous decades old bugs recently found, the concept of many eyes needs to die.

And in the case of SMTP, it's basically a pinata of bugs for the last 30 years regardless of platform

Re: Meltdown Update Kernel doesnt boot

#170

Post by zoe1337 »

1stranger wrote: post #140
dbenhur wrote: post #114

Earlier quoted context omitted.

Most vehicle recalls are not of the form: return your vehicle, we give you a new fixed one; but rather: bring your vehicle to one of our dealers and they'll perform some action to repair the defect. The later is pretty analogous to issuing firmware and OS patches to mitigate the flaw.

What if the fix to the car reduced your MPG by 30% to address a safety issue? This seems somewhat analogous to the number being bandied about as the CPU performance decrease. (Depends on workload, etc, etc.) I think most car owners would expect some kind of compensation for a product that no longer has the same efficiency as when they bought it.

This issue is similar to what happened with the Volkswagen emission cheat. After they fix the ECU to have the advertised NOx emissions, the car lost peak power and fuel efficiency.
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