Linux @lemmy.ml Prunebutt @feddit.de 1y ago

Question: is systemd-homed ready for everyday use yet?

Hi! I want to try out fedora workstation in the near future (once 39 is out) and was wondering if systemd-homed is ready for everyday use yet.

I'm a bit paranoid and really need my private data encrypted. However, I don't think that full disk encryption is practical for my daily use. Therefore I was really looking forward to the encryption possibilities of systemd-homed.

However, after reading up on it, I was a bit discouraged. AFAIK, there's no option to setup systemd-homed at installation (of fedora). I was an Arch then Manjaro, then Endeavour user for years but don't have the time/patience anymore to configure major parrts of my system anymore. Also, the documentation doesn't seem too noob-friendly to me, which also plays into the time/patience argument.

Is it ready? Can anyone seriously recommend it for a lazy ex-Arch user who doesn't want to break another linux installation?

Thank you in advance. :)

73 comments

To go back to basics, why is FDE not suitable for your needs?
- I second this.
  
  Full disk encryption is entirely practical for everyday use. If you don't already have a dedicated TPM, your motherboard/CPU may provide a software TPM (fTPM?). If so, you don't even have to interact with the machine during boot. It's just a bit slower to start up (by a few seconds), which really isn't a big issue for your average user.
  
  Pardon my ignorance here, but I don't get it how is the whole thing still safe with unlocking from TPM instead of me providing the password at boot time?
  
  Considering now anyone can just boot the machine into the installed system then bruteforce/exploit something to get login/get read permissions and make a plain copy of the data?
  Where, without tpm, as long as I do not type in the encryption password myself I have a pretty high guarantee that the data is safe, especially when I am not at the (powered down) computer.
  
  TPM is only kinda related to FDE, in that it can be used to unlock a LUKS encrypted volume. FDE doesn’t require a TPM.
  
  I also wouldn’t recommend automatically unlocking your root partition on boot using the TPM as this allows access to your data if the device is stolen, which, for an average user, defeats the main purpose of FDE.
  
  As others explained: If the FDE key is in RAM, I'm vulnerable. My thread model includes a stolen Laptop with the attackers able to freeze my RAM and reading out the keys.
  
  Thank you for mentioning TPM though. Didn't know of that before. :)
  
  There are plenty of reasons to not want FDE or not want just FDE alone. Shared computer, your data isn't safe if you share the FDE password with another user who needs to share the system. He said he's paranoid, so he is wanting his data encrypted above all. Home directory encryption, especially on top of FDE, while a performance hit, would do well for that. But most importantly, he said FDE isn't practical for him, end of FDE story.
- That's not answering his question.
  
  I'd like to tell you why you get downvoted:
  
  https://en.wikipedia.org/wiki/XY_problem
  
  X Y problems exist. And are fairly common in IT. That's why it's a good idea to ask questions like this.
- Simple convenience. I usually don't have the time to wait one or two minutes until my full disk is decrypted (I am often late and the only person in a group meeting who brought a laptop for taking minutes).
  
  I also use a weird keyboard layout (Neo 2) and I never got grub to load with that layout. Typing a 40+ passphrase in QWRETZ is just cumbersome to me.
  
  Also: I hate to admit it, but I am a bit vain and simply would like a nice gui for entering my password.
  
  Edit: I forgot to add that I'm playing with the idea of getting a surface tablet and installing linux on it. Then I couldn't count on awlays having a usb keyboard with me.
  
  I have a LUKS-encrypted laptop (1GB SSD), it takes about 10 seconds between typing in the password and the start of the boot process.
  
  You can setup FDE that utilizes TPM like Windows does with bitlocker, in such a way that your backup phrase is only necessary if something about your hardware changes.
  
  Last I set it up however, there wasn't any easy/automatic way. Searching "luks TPM" should get you started.
  
  Would a FDE with FIDO2 hardware key meet your needs?
Never used systemd-homed, but i know an alternative to full disk encryption is having the root partition unencrypted, and the home partition unlocked at boot. For a single user machine at least, i don't see any difference when using it than unlocking at login. But then having 2 partitions is mandatory, and that may be a problem when running out of space.
Works for me on arch linux. No hickups or anything and I am using it since it was first announced.
I read from your answers on other comments, that you do want to have even protection if someone forces you to give up your password and at the same time have the convenience of a quick boot process and avoid full disk encryption? (Not provoking, just want to make sure I get you right). Please consider, that if you don't make your thread-model clear it will be really hard to give a proper advice.

Please be aware that it's often a trade between usability and comfort on the one hand and proper security on the other hand. I'm not really sure if you want to target both at the same priority, that might not work out. You will not achieve Maximum convenience and maximum security at the same time.

If you want to actually commit to high security, there's a thing with LUKS or VeraCrypt supporting plausible deniability. Main concept is, you have one key that decrypts sort of a mock up file system with uncritical data (or misleading, slightly compromising stuff, however you want to play it). Then you have a way longer key, that unlocks the actual data. This can cover your ass for the thread model of some actor forcing you to give up you password. Have a look at the VeraCrypt documentation on plausible deniability.

Another great read for me was hitchhikers guide to online anonymity. Might be off topic, but there are some great advices and guides to increase your anonymity and considerations about online security too. If you want to go fully paranoid on a Snowden level, that might be you way to go. Took it as a inspiration to get myself a QubesOS setup and got a lot of insights with that one.

I really don't want to discourage you, it's the opposite! I appreciate everyone thinking about how to secure their stuff properly, but be aware that you might need to dig yourself deep into it, if you want to achieve the goals you mentioned.
- Wow! Thank you for the thorough answer!
  
  You misunderstood one thing, though: I don't consider someone forcing me to give up my password to be a valid attack vector. My devices can be stolen and all hardware keys with them. But I woun't get blackmailed to give anything up. Maybe plausible deniability is a good backup, though.
  
  I'd like to go into further detail, but I feel like I already said too much for a non-throwaway account.
  
  I do realize that convenience and security are a two ends of a see-saw. Thank you for the Vera.crypt hint. Even though I don't know if I would use it, it sure sounds interesting.

73 comments