Protecting against rogue devices with Full Disk Encryption and TPM
Protecting against rogue devices with Full Disk Encryption and TPM
news.opensuse.org
Protecting against rogue devices in openSUSE with Full Disk Encryption
18 comments
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Integrated TPM chips have been busted for a while
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TPM + Pin with Secure Boot is still unbroken AFAIK
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And as far als inux goes, physical access to TPM is game over
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Is it possible to configure the kernel to allow access to decrypted contend only through the user session?
Theoretically, kernel keys can be set to be readable only by the user session, and in an uncompromised root is not able to read those keys. I can imagine a filesystem encryption design that uses a user session key to en/decrypt data on the fly using a user session key, such that not even root or a process in another user session could read the mounted filesystem.
Does such a system exist? As I understand, this is not the way dm-crypt or LUKS work. FDE and TPM are still vulnerable to hacking while everything is running, unlocked, and mounted.
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I believe thats how Android works. As I recall, it uses fscrypt.
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Isn't setting up fscrypt on your home partition enough?
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Not really. Imagine they replace the ssh binary with a back doored version. Home directory encryption protects your data but not your system.
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18 comments
Automated TPM2 LUKS setup might be the one thing that can get me to switch from Fedora to OpenSUSE.
TPM unlocking FDE is complicated for me. I fully understand measured boot and support it, but it seems less secure to me than manually unlocking the disk.
Once the disk is unlocked and you’re put onto the display manager, I feel like there are many more vulnerabilities that could be exploited to gain access to your data.
With manually entering the disk password, the data is locked. You either need to brute force it or use the XKCD wrench method.
So I feel TPM+Pin is the best for security. Unfortunately Aeon, which is based on OpenSUSE and implements TPM, doesn’t support TPM+Pin. I think it’s mainly due to how poor and widespread TPM support is. It could lock you out entirely.
What makes TPM+pin safer than just having a normal LUKS password? I would think it would be the same amount of security just with more chance of data loss if your computer gets damaged
Yep, you need a pin for your TPM to be safe. Here's a proof of concept of someone unlocking Linux systems without TPM pin.
https://oddlama.org/blog/bypassing-disk-encryption-with-tpm2-unlock/
As I understand it the TPM is for people who have physical access. It prevents them from cloning your disk.
I think with an adequately long password (or an adequately resource-intensive encryption algorithm) you can secure your disk enough to prevent unauthorized access. But the TPM would prevent them from removing your hard-drive and shunting it into a super-computer (so all password attempts wouldn't need to be on the crummy 10-year old laptop CPU) so a TPM + password is more secure.