Fellow selfhoster, do you encrypt your drives where you put data to avoid privacy problems in case of theft? If yes, how? How much does that impact performances? I selfhost (amongst other services) NextCloud where I keep my pictures, medical staff, …in short, private stuff and I know that it’s pretty difficult that a thief would steal my server, buuut, you never know! 🤷🏻♂️
Yes.
My home server has dropbear-initramfs installed so that after reboot I can access the LUKS decryption prompt over SSH. The one LUKS partition contains a btrfs filesystem with both rootfs and home as subvolumes. For all the other drives attached to that system, I use ZFS native encryption with a dataset that decrypts with a keyfile from that rootfs and I have backups of an encrypted copy of that keyfile.
I don’t think there’s a substantial performance impact but I’ve never bothered benchmarking.
I want to, but haven’t found the time to make a strategy on how to move over the data. It would take a bunch of shuffling as all drives are in use. The next problem is decrypting at boot and securely storing the decryption key - if I choose to use a decryption key at all. Maybe it’ll be a usb key that I have to plug into the server when starting it, or I have to setup decryption of the system over SSH, but that means automated restarts are… difficult.
Not sure how to tackle the problem yet…
I use separate disks for data storage and my OS. That way a headless system can boot and all the services like SSH can become available, and I can decrypt the data drives remotely.
When there’s an unexpected reboot I can still get into my system and decrypt remotely which is nice. I can also move the data storage disks to another system without too much hassle.
I did have to make sure some services were fault tolerant if an encrypted volume was unavailable when the OS booted. An example of this might be torrenting software, I needed to make sure the temporary storage was on an encrypted volume. The software had a sane fault mode when the final storage location was unavailable, but freaked out for some reason when the temp storage was missing.
Once set up the whole thing is pretty easy to manage.
I did have to make sure some services were fault tolerant if an encrypted volume was unavailable when the OS booted
How did you achieve that? systemd dependency?
I’m pretty sure I didn’t mess with systemd, though that would probably be the right way to handle it.
I was able to update a runtime config so if any storage wasn’t available it just halted the service. Then I created a short script I’d invoke manually which decrypted the luks drives and brought the dependent services up. I also added monitoring to alert me when the drives weren’t available for whatever reason.
It’s a relatively low performance hit and it benefits me when having to replace a failing/old disk. I can just toss the drive without having to erase the data first, that is as long as the key is a secure length.
No. If someone gets to my server that’ll be the least of my worries.
I keep my drives encrypted with a key currently hosted in my router hoping they wouldn’t steal that. I’m thinking of actually putting it to cloud so I can disable it remotely.
It was quite a ride to make everything work and I made a blog post explaining it so I remember what I did.
https://nowicki.io/self-hosting-lvm-raid1-with-key-over-ftp/
Interesting, thanks!
This shouldn’t even be a question lol. Even if you aren’t worried about theft, encryption has a nice bonus: you don’t have to worry about secure erasing your drives when you want to get rid of them. I mean, sure it’s not that big of a deal to wipe a drive, but sometimes you’re unable to do so - for instance, the drive could fail and you may not be able to do the wipe. So you end up getting rid of the drive as-is, but an opportunist could get a hold of that drive and attempt to repair it and recover your data. Or maybe the drive fails, but it’s still under warranty and you want to RMA it - with encryption on, you don’t have to worry about some random accessing your data.
If you’re getting rid of a (rusty) drive and it leaves your hands with the cool magnets and shiny frisbees still inside, you’re doing something wrong.
Dude just use a hammer
I did have LUKS and a USB flash drive with a key to be inserted on boot. It was definitely difficult and caused performance issues. It was particularly difficult to add/remove drives from the array. These days I only encrypt my off-site backups that sit at the office where my coworkers potentially have physical access.
There have been recent advancements in TPM so disk encryption is easier to maintain and doesn’t affect performance. I’ll need to investigate this one day. My server/NAS is a 4th-gen i5, so it may not support the functions I would need. Full disk encryption will land in Ubuntu soon. I’m hanging out for that.
How do you even encrypt a server so that it doesn’t require human intervention every time it goes down/restarts?
I remember this blog post (I cannot find right now) where the person split the decryption password in two: half stored on the server itself and half on a different http server. And there was an init script which downloaded the second half to decrypt the drive. There is a small window of time between when you realize that the server is stolen and when you take off the other half of the password where an attacker could decrypt your data. But if you want to protect from random thieves this should be safe enough as long as the two servers are in different locations and not likely to be stolen toghether.
Isn’t that what a TPM could be used for?
I’m too lazy to look up the details. But you can have a small ssh server running as part of initrd. I think it’s dropbear. I log into that and unlock the root drive from there.
Of course that necessitates an unencrypted /boot/.
Did it on Debian and it was relatively easy to set up.
I‘m in the process of setting up a new NAS with Debian and disk encryption, and this is exactly what I’m struggling with. I’ve tried multiple guides for Dropbear but every time I try to SSH into the server to unlock it, I get “Permission denied”.
This answer here covers it quite nice imo.
Important is that you update your initramfs with the command after you edited the dropbear initramfs config and or you copied the key over.
For the client it is important to define 2 different known hosts files since the same host will have 2 different host keys, 1 when encrypted with dropbear, and 1 when operational with (usually) sshd.
Also you need to use root when you connect to your server to unlock it. No other user will work with the default setup.
I was actually using my own user account instead of root, but now that you mention it… I’m not sure how that would even work so yeah that makes sense.
I did rebuild the initramfs after every change but did not manually copy the key file anywhere other than etc.
Will check out the link tomorrow. Thanks a lot for sharing!
Edit: tried again with root and it worked flawlessly :D
Files could be decrypted by the end user. The OS itself could remain unencrypted.
TPM, but it’s a pain in the ass and breaks a lot. The new version of Ubuntu should handle it better, but if you’re not on Ubuntu, that won’t help you.
TPM solves a sigthly different threat model: if you dispose the hd or if someone takes it out from your computer it is fully encrypted and safe. But if someone steals your whole server it can start and decrypt the drive. So you have to trust you have good passwords and protection for each service you run. depending on what you want to protect for this is either great solution or sub optimal
How do you even encrypt a server so that it doesn’t require human intervention every time it goes down/restarts?
The only time my Server goes down, is when i manually reboot it. So waiting a minute or two, to ssh into it and entering the passphrase is no inconvenience.
Nope. This isn’t part of my threat model.
I don’t have sensitive data and stealing a drive would be inconvenient for a thief.
You don’t have sensitive data? Would you mind expanding on that a bit for me? Just curious how you like, live, and stuff.
I’m surprized as well, like I guess I would understand if it’s a no log DNS server but, what else wouldn’t have sensitive information.
Plex data, pi hole, and home assistant don’t contain anything meaningful. No credentials are stored in a form that can be reused.
The most sensitive is immich, which I’m more concerned about backups than I am someone might steal my nudes. Their online anyway.
Email is hosted off-site and I still have physical files for a lot of my documents. If someone stole hdds out of my server, they’d get a lot of Linux isos, pictures of cars, porn, tons of versioned software and games installers, etc.
Maybe my definition of sensitive is different than yours though.
I don’t do anything that warrants it, but if I did have sensitive data that I was worried about being stolen, those drives would be in a system completely cut off from the Internet to prevent remote theft, and encrypted in the event of a physical theft. If I was especially paranoid, I’d booby trap the drives to wipe themselves if they are tampered with.
Have you tried secure-erasing a disk?
Absolutely yes, I do enctypt my drives so I don’t have to ever do that again. This isn’t as critical for SSDs but it’s still a good idea. Even if you keep the key stored on the same system, securely deleting a tiny file is way easier than a whole disk.
Have you tried secure-erasing a disk?
Once /dev/urandom is enough. Who cares if a state actor could theoretically recover your media library in an expensive lab.
Even that takes a while.
And it has other benefits. For example a dying disk. You can just throw that out. I once tried to wipe such a disk and it’s a chore. It makes weird clicking noises and slows down to the point where it’d take years to overwrite it. Occasionally the SATA controller resets etc. And it won’t succeed at overwriting stuff. Sure I could go to the garage, get the power tools, put the hdd into a vise and delete everything with a combination of hammer and drill… But it’s much more convenient to have it encrypted and not care.
You take the disk out, drill once through it (use a metal bit).
Done.
Takes a couple minutes.
Sure. It’s just effort. I have to go fetch the power tools, fetch the drills, if I want to do it correctly also mount a vise or go fetch a piece of scrap wood and some clamps… After that clean up and remove the metal chips from my apartment…
At work I’d additionally need 3 training courses to be allowed to operate the drill press and visit the workshop. The whole process is going to take half a year. And it’ll still not be certified that the information is now gone.
In an enterprise setting, it’s probably a bit of a hassle with everything having to follow some kind of process…
Somehow they don’t trust the software developers with operating heavy machinery 😆
Anyways, I think we’re moving away from the topic… At work I didn’t encrypt harddisks anyways. They just put the servers into a special area in the datacenter that has a fence and a separate lock.
At home I just encrypt stuff so I don’t have to remember what I put where and handle things differently. Of course everything depends on the specific scenario and threat model. I have a bit of stuff archived on my server that isn’t around anymore, could be a copyright violation. I also have my complete life stored there, documents, finances, emails of a decade, pictures, backups for family members, passwords for emergency access to things. Admin stuff and logfiles that I’m required by law (GDPR…) not to share. I also used to travel a lot with my laptop in the backpack and that can get stolen. At some point a long time ago I decided to encrypt my harddisks and stop worrying. Since at least 10 years there isn’t any speed penalty anymore and it takes like 20 seconds to set it up on Linux…
But I can also see why not everyone wants to do it this way.
Takes me about 2 seconds with a 5lb steel mallet.
I have two WebDAV shares, one unencrypted and one encrypted. The unencrypted one is for things that need to be read by other services, like legally obtained movies and tv shows. The encrypted one is for porn, mostly (also stuff like tax documents, legal contracts, etc).
This is the server I use
https://hub.docker.com/r/sciactive/nephele
It’s really easy to set it up for encryption. Also, I wrote it. :)
Do you honestly encrypt your porn? Why? (Assuming it’s legal)
How are you certain all your porn is legal?
I think we both understand the intention behind my statement
Good question. I don’t have a clue either. It doesn’t contain any personal information. (Unless it’s self-made.) Usually isn’t unique. And nobody cares as there’s an abundance of porn available everywhere on the internet.
No,
There is all the backup of all my family pictures in the drives.
If something happens to me I want to make due that they will have access to it.
On laptops yes, on my server no. Most of the data is photo backups and linux ISOs form over the years.
Always, if nothing else it makes “wiping” them securely easier.
