mkopec

Joined 5 years ago

Karma
183
Submissions
56
Member since
Aug 6
Open-source firmware engineer.

All opinions mine unless expressly stated otherwise.

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Recent submissions

Comment · 1 day ago
Well, by sealing the LUKS key to a TPM you can get rate limiting. Of course then you need to trust the TPM to do its job correctly, and we're back to the same potential issues as with HW disk encryption, but to be honest I'm going to trust a TPM over OPAL any day. Especially the Google Ti50 in my chromebook.
Comment · 6 days ago
may I introduce you to coreboot and LinuxBoot?
Comment · 1 month ago
Platform: ASRock Rack SPC741D8, Xeon Sapphire Rapids. Firmware: Dasharo, coreboot + edk2 payload. Launch path: GETSEC[SENTER] with the SINIT ACM, Xen and dom0 measured into PCRs 17-18.
Comment · 1 year ago
> If all DVD players came with watermark detection instead of copy protection

That is an enormous "if". Do you think Microsoft is going to or is able to enforce this on every single software provider? Even in your Android example that's just not happening, and you can happily sideload apps. You can still develop your own apps on the same Android phone that you use for banking.

> And sorry but how many people have bypassed Playstations or Switches. This is what you’re talking about. Most people will just accept it.

People accept this with consoles because a console is a device exclusively for consuming media, and all developers apply for a devkit. I just don't see that happening in the PC space. You think Microsoft is suddenly going to dump this on third party software developers and force everyone to go through certification and to buy devkits? Without a mass exodus to Linux?

Comment · 1 year ago
Google SafetyNet is basically swiss cheese with lots of bypass solutions for custom ROMs.

A TPM may only attest that it has received an expected set of measurements (hashes). As long as discrete TPMs or PCs with unlocked CPUs exist (w/o Boot Guard), one may simply take a TPM and replay "golden" measurements to it. Bypassing this would be trivially easy.

A TPM does not have control over execution on the CPU. It only receives data from the CPU. If you have control over execution on the CPU from the reset vector, you can just replay whatever you want to a TPM and extract secrets that way. That's why TPM backed disk encryption without configuring a PIN is insecure.

Microsoft does not have the same level of control over the entire PC ecosystem as Google has over Android. That's why it's important to support open source alternatives.

Comment · 1 year ago
Widevine L1 requires a trusted execution environment for decrypting video and only showing it on HDCP monitors. It's built on top of Intel PAVP, AMD secure display, or ARM TrustZone in the case of ARM chromebooks and Android devices. TPM is not involved, except in the ARM case where I believe it is used for antirollback counters (on x86, the security coprocessor would probably have that responsibility).
Comment · 1 year ago
> Does TPM support/requirements actually have any meaningful impact on a home user?

Disk encryption, Windows Hello and PIN bruteforce prevention. I have no love Microsoft and avoid using Windows whenever I can, but I think making those features accessible to more people is a good thing.

Comment · 1 year ago
There are none. It's so immensely frustrating to me that so many people believe that a TPM is a DRM device. I'm sure Richard Stallman's Treacherous Computing article played a big part in this.

A TPM is useless for DRM, and there are way more suited solutions like Intel's PAVP that takes an encrypted video stream and puts it on the screen directly, yet I don't see nearly as much uproar about that.

Comment · 2 years ago
I think if the process was made easy, it would save quite a bit more than 1% of these devices from the landfill, assuming you have enough power users to build a community. Plenty of people flash their chromebooks to MrChromebox UEFI to give them a new life, because it's easy enough for mere mortals, and because Google doesn't lock them down.

I believe if given the tools, people would gladly donate their time to make something fun with it. Heck, that's what I do in my spare time. But it's impossible if everything is completely locked down, as if a music streaming box contains nuclear launch codes that must be protected at all costs.

Comment · 2 years ago
I firmly believe that permanent key fusing to lock bootloaders should be outlawed. At the very least the keys (and schematics) should be released once the device reaches EOL.

Otherwise we're just manufacturing e-waste.

Comment · 2 years ago
Yeah, that's not something anyone should be saying to random people online.
Comment · 2 years ago
Do Android Auto and VoLTE / VoWiFi work on Graphene these days? I also remember Google Maps and Uber being extremely problematic

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