i’m lizard

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Joined 1 year ago
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Cake day: June 21st, 2024

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  • PUID is indeed handled inside the container itself, it’ll run a container-provided script as whatever the container’s UID 0 happens to be first which then drops to whatever $PUID happens to be inside the container. user= is enforced by Podman itself before the container starts, but Podman will still run as root in that setup. That means Podman is running “rootful”, while if you started the container manually as $uid using the regular Podman CLI, it would be “rootless”. That is a major difference in a lot of respects, including security, and you can find quite a bit of documentation on the differences between those operating modes online; it wouldn’t fit in a comment. Rootless is generally considered the better mode, though there are some things that still require a rootful container.

    In the upcoming NixOS 25.05 or current unstable, there are some tools you can use to run containers rootless as another user more easily using a new $name.podman.user = ""; setting. From what I understand they’ll still be root-managed systemd system services that require sudo to operate, but that means privileges get dropped by systemd before running Podman, instead of dropped by Podman before running the container. This stuff is recent and I haven’t used it, I just happen to know it exists, relevant nixpkgs commit if you wanna dig into it yourself: https://github.com/NixOS/nixpkgs/commit/7d443d378b07ad55686e9ba68faf16802c030025



  • Borg or the like with ‘hardcoded’ plaintext/regularly full-disk-encrypted key is acceptable. Someone that has your unencrypted private key sitting on your server has almost certainly already obtained access to the entire set of data you’re backing up, with the backup key itself only meaningfully guarding access to older backups.

    The more important thing is to securely keep extra copies in case the server fails. I keep mine in a group in my password manager, one per repo.



  • (It’s a joke/reference, I guess it’s not 100% known though. My bad.)

    I really do hate “I know what I have so you are going to pay whatever number I set” capitalism though, which is what they do here. These registrars figured out a loophole around the redemption grace period and are, from the start, set up to make you lose the domain and then spend significant money on a completely unfair auction where they have the power to plant fake bids, rather than paying the usual static redemption fees that aren’t that excessive.



  • You go to the settings and verify it. You don’t have to host anything, just verify that you own the domain via text file or DNS record and choose to set it as your handle. Bluesky’s ATProto has a couple extra layers of indirection and it’s very easy to get a custom handle as a result.

    The downside of this setup is that running your own complete network is completely impossible. If you want to follow theonion.com, anyone can find did:plc:a4pqq234yw7fqbddawjo7y35 in the DNS without too much work. That’s the identifier for The Onion’s Bluesky account, and even if they swapped back to .bsky.social, that ID number would stay. But that DID tells you absolutely nothing about where the data is currently hosted.

    So how do you figure that out? Well, you register it with https://plc.directory/ which is ran by Bluesky and cannot currently be replaced. There’s fancy cryptography involved that makes it hard for them to spoof data, but they are perfectly capable of simply not giving any data out for any given DID.



  • Sorry, I’ve had a (self-imposed) busy week, but I have to admit, that also has me rather stumped. As far as I can tell, your second entry should work. If the device is visible in /dev/mapper under a name, it should be able to mount under that name.

    The only thing I can think of is that some important module like the ext4 module might be missing somehow? You can get pretty confusing errors when that happens. Dracut is supposed to parse /etc/fstab for everything needed to boot, and maybe that’s not recognizing your root for some reason. dmesg might have some useful info at the end after you try to mount it. If that’s what’s happening, you could try to add add_drivers+=" ext4 " in your dracut.conf and regenerate it (the spaces are important!). But if that’s not it, then I’m probably out of ideas now.


  • I think you should check your root= line and add a rd.luks.uuid= to make it open it. Dracut will by default open the root FS as /dev/mapper/luks-abcdef... based on the LUKS container UUID. You can get that with cryptsetup luksUUID. /dev/mapper/root is just never going to show up unless you’ve assigned a custom name to that with the barely documented rd.luks.name, and I don’t see that in your setup. The cryptroot and cryptdm parameters aren’t used by Dracut either.

    With all of that missing it’s just gonna wait for that /dev/mapper/root to magically show up out of nowhere, without ever trying to open it.

    A correct cmdline will probably look something along the lines of root=/dev/mapper/luks-<uuid> modules=sd-mod,usb-storage,ext4 rootfstype=ext4 rootflags=rw,relatime rd.luks.uuid=<uuid> and once opening with passphrase works, you can start to mess with rd.luks.key=/awesome.key (and readd quiet when done debugging, if you want it that way).

    ldconfig errors and the missing modules should be fine. musl’s ldconfig is just a bit different but also isn’t required in quite the same way. I don’t think you should need to mess with modules manually. I don’t think you’re using LVM’s userland for your setup, just all the device-mapper kernel modules. Dracut will pull all the necessary bits in for you if you’re setting it up for LUKS.




  • Dracut may have this functionality already built in via rd.luks.key, so a custom module would really only make sense if you’re trying to do more than that. You can probably get away with just using that if you just want it to work, but if you want to customize stuff:

    I suspect your module is running well after the device is already supposed to be cryptsetup opened. The way the default crypt module handles it is by setting up udev configuration in a very early phase, and then having udev request the password a little bit later when it finds the device it’s trying to open, until all devices are ready. It’s a complex mechanism compared to Alpine’s straightforward script, but it’s much more flexible when it comes to ordering of things like RAID/network devices/LUKS/etc.

    The result of that is that your code would have to run much earlier. There’s some documentation on how hooks work, and the builtin rd.luks.key / keydev handler runs at cmdline 10. That’s well before your pre-mount, and probably where you’d want to run your code. Based on a cursory inspection of the other code, you could either cryptsetup open it yourself if you use the name it expects (rd.luks.name= cmdline parameter or luks-$luks_container_uuid), or you could use that /tmp/luks.keys mechanism (it’s a dracut-internal thing so you won’t find much documentation, but it lives in crypt-lib.sh, cryptroot-ask.sh and probe-keydev.sh).

    As for debugging, the cmdline manpage has a few decent enough options. rd.break=cmdline or similar can force a shell before Dracut goes through a specific phase of hooks. You should be able to manually test doing things similar to your script at that point.


  • You’d be looking for /usr/share/mkinitfs/initramfs-init . I’ve never customized that myself, but it looks like there’s already some support for a keyfile if you look for KOPT_cryptroot and check that block of code. That looks like it’s mostly set up for a keyfile embedded into the initramfs, but I guess it should be possible to replace that code with something that grabs the keyfile off an USB drive.

    I suppose you’d make a copy of it, put it somewhere in /etc or whatever and change the mkinitfs.conf to point to it. init="/etc/whatever/myinitramfs-init" should do the trick since the config file just gets sourced in. That said you’re definitively heading into unknown territory here. It might be easier to just use Dracut or the like instead.