faulTPM: Exposing AMD fTPMs' Deepest Secrets • Hacker News Board

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#141

Post by hypercube33 » Tue, May 02, 2023, 5:20 PM UTC

als0 wrote: post #67

mastax wrote: post #36

Earlier quoted context omitted.

> there has been a lot of push around moving to things like ARM for energy efficiency reasons There has? Where? Specifically for Windows PCs, not chromebooks or apples.

Not got a reference but one of the new Lenovo ARM laptops claims to have 26 hour battery life. If true then that's pretty compelling.

An AMD Lenovo Laptop supposedly gets 16 hours of battery life and again, this is subject to what you're running, but it runs x86 stuff natively instead of having to translate it. Isnt this 'good enough' for most people? I know we have people wanting week long laptop batteries, but over 12 solid, real world hours should be good enough for the majority of users, I'd think.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#142

Post by kfreds » Tue, May 02, 2023, 5:20 PM UTC

dathinab wrote: post #131

als0 wrote: post #112

Earlier quoted context omitted.

TPM is more or less an API specification. The specification is fine but people are worried about implementation backdoors and pre-provisioned keys. It should be possible to have an open source public trustable implementation that anyone can synthesise onto an FPGA or a real chip design. This ought to avoid fears about backdoors, while keeping a mature security model and good software support. I suspect there isn't su…

> I suspect there isn't sufficient demand or skill for such a project. IMHO more like: There is little to no profit in this, nor much motivations for AMD/Intel to provide this. But it does involve additional work, especially if the fTPM implementation they use currently does (partially) use code they got from other companies which they can't open source. Through you wouldn't need a FPGA, for a TPM to really be secure…

As I'm sure you're aware FPGAs are nice because they can complicate things for an attacker in the physical supply chain. Andrew "bunnie" Huang did an excellent talk on the subject:

https://www.youtube.com/watch?v=Hzb37RyagCQ

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#143

Post by hnj2 » Tue, May 02, 2023, 5:21 PM UTC

labcomputer wrote: post #73

dathinab wrote: post #46

Earlier quoted context omitted.

no they are for boot chain security which is an essential featur for any laptop TPM by itself never prevents anyone from doing anything but it's used with features like secure boot, but as long as they fully implement the spec they don't prevent you from doing with your laptop what you want as long as you don't install software which does so secure enclave and similar used for DRM isn't directly a TPM feature but mor…

Erm… yes, actually. For DRM to work, it has to be running in a trusted environment where the user can’t just load up a debugger as superuser and read the keys from memory. The way you do that is by using secure boot to ensure that you are running a trusted kernel that enforces appropriate access controls… which requires TPM. One of the main selling points of TPM is that you have chain of trust to ensure the boot proc…

Author here: TPMs are not a TEE (trusted execution environment), and the TEE included in AMD's CPUs function completely separately from the TPM. So you could disable the TPM and still have the TEE run DRM code.

The fact that both TEE and fTPM run on the PSP (or AMD-SP) might add a little confusion, but is nevertheless interesting.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#144

Post by gambiting » Tue, May 02, 2023, 5:22 PM UTC

ekianjo wrote: post #71

r2_pilot wrote: post #19

Earlier quoted context omitted.

Microsoft is edging closer and closer to dropping support for Windows 10(even a computer I built in 2017 that's still running perfectly fine can't upgrade). But for many users, changing to another OS besides Windows is tantamount to not functioning, so planned obsolescence continues apace.

Don't reward them for that. The only solution is to move to another OS, that's the only thing they will ultimately understand - no matter how inconvenient it might be.

That's not an option if you use your machine for work and your Dev tools only work on windows. PS5/Xbox toolchains only work on windows, as a gamedev I don't really have a choice.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#145

Post by BlueTemplar » Tue, May 02, 2023, 5:22 PM UTC

charcircuit wrote: post #103

taraharris wrote: post #31

Earlier quoted context omitted.

TPM's true owner is the NSA, not you or I. https://www.stat.rice.edu/~dobelman/kstorm.txt https://news.ycombinator.com/item?id=6337282 https://www.militaryaerospace.com/computers/article/16711478... https://www.businessinsider.com/leaked-german-government-war... https://supplychaindigital.com/technology/nsa-trusted-comput... https://redmondmag.com/articles/2013/08/22/windows-8-securit... https://blogs.ncl.ac.uk/secur…

Protecting American's, American businesses', and the American government's security is in the interest of the NSA.

Probably, but the biggest issue here is that most people aren't American, even on this website.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#146

Post by Cheeeetah » Tue, May 02, 2023, 5:23 PM UTC

wkat4242 wrote: post #126

Cheeeetah wrote: post #106

Earlier quoted context omitted.

TPM allows government to request your data in the first place. So it should not be trusted by individuals from the beginning.

Uhh what? How does that work? Where do they request it? The TPM manufacturer? Microsoft? TPMs aren't very secure and as a discrete component their connection to the CPU can be intercepted (unlike fTPM or apple's integrated solutions).. There's a big difference between having a deliberate backdoor and just a vulnerable design that can be exploited. I haven't seen them accused of being backdoored. Intel's ME (and AMD's…

The manufacturers perhaps. They provide the keys in the modules anyway.

BTW, there is Chinese passport law which states that the algorithm should be independently developed. The law once blocked TPM 1.0 but allows TPM 2.0

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#147

Post by xxpor » Tue, May 02, 2023, 5:25 PM UTC

Workaccount2 wrote: post #30

r2_pilot wrote: post #19

Earlier quoted context omitted.

Microsoft is edging closer and closer to dropping support for Windows 10(even a computer I built in 2017 that's still running perfectly fine can't upgrade). But for many users, changing to another OS besides Windows is tantamount to not functioning, so planned obsolescence continues apace.

I wish there was a linux distro made by people who love windows, not linux.

This is what I ran in 2002 or so: https://en.wikipedia.org/wiki/Linspire

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#148

Post by hnj2 » Tue, May 02, 2023, 5:26 PM UTC

als0 wrote: post #122

cwerling wrote: post #18

Earlier quoted context omitted.

One of the authors here. This attack is relevant if your machine is physically exposed to attacks, e.g., in an office environment or while traveling, and if you don't use any additional pre-boot passphrase to protect the disk (but rely solely on AMD's fTPM). When TPMs became popular, dedicated TPMs were mainly used, being a separate chip on the mainboard connected via the SPI or LPC bus. These were prone to (relative…

> These were prone to (relatively primitive) bus sniffing attacks, where you would hook up a Logic Analyzer to the bus, watch a regular boot procedure grab the disk key, and then use software like Dislocker to extract all data from a USB Live Linux or alike. The TPM supports encrypted sessions, but they are opt in. See Parameter Encryption in the TPM spec. The issue is that Bitlocker doesn't use them for whatever rea…

We haven't looked to much into encrypted sessions, but for anyone wondering how they prevent MITM attacks in such a scenario: systemd-cryptenroll seems to be ahead in this regard: https://github.com/systemd/systemd/commit/acbb504eaf1be51572...

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#149

Post by BlueTemplar » Tue, May 02, 2023, 5:30 PM UTC

Sunspark wrote: post #124

anthk wrote: post #84

Earlier quoted context omitted.

And IntelME.

I sometimes wonder if it'll be a selling point of Chinese CPUs in the future, "our CPU might not be the fastest, but it's the only one running at any given time!". People don't need "flagship" CPUs for every single purpose. There is no reason why one cannot have a slower more private system for specific purposes, say general purpose computing, and the faster one with the autonomous network-aware CPU and OS be used fo…

Issue here is that I trust the Chinese even less to not have something like this hidden in the hardware.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#150

Post by mardifoufs » Tue, May 02, 2023, 5:33 PM UTC

jeroenhd wrote: post #47

doubled112 wrote: post #32

Earlier quoted context omitted.

I did find it odd that my Ryzen 7 1700X (8 cores, 16 threads, 3.4GHz) was suddenly "not good enough" to run the OS.

It'll work fine, Microsoft even explains how to upgrade: https://support.microsoft.com/en-us/windows/installing-windo... They chose an arbitrary cut-off date for hardware support for their new OS. They decided not to support old stuff anymore and they had to pick a date/technology platform. It was always going to be arbitrary. In my opinion they should've picked a clearer distinction (i.e. require a certain level of…

Which is amazing since windows 11 is full of mentions of green energy, lowering energy consumption and asking you to lower screen brightness to lower carbon emissions. Total green washing when you consider the gigantic amounts of ewaste that arbitrary cut off date will lead to. It's just funny tbh, like I get it's most likely very different teams working on those things but it's tone deaf at best.

But hey at least the OS has a revolutionary new green technology called... Battery saving mode!