(More) Specifics:
- Undoing the protection should include filling in a password.
- The password should be different from the one used with
sudoor any other passwords that are used for acquiring elevated privileges.
All (possible) solutions and suggestions are welcome! Thanks in advance!
Edit: Perhaps additional specifications:
- With 'displace‘, I mean anything involving that resembles the result of
mv,cp(move, cut, copy) or whatsoever. The files should remain in their previously assigned locations/places and should not be able to ‘pop up’ anywhere. - I require for the files to be unreadable.
- I don’t care if it’s modifiable or not.
- I don’t require this for my whole system! Only for a specific set of files.
It sounds like you’re actually more concerned about the data in the files not being able to ‘pop up’ elsewhere, rather than the files themselves. In thus case I’d suggest simply encrypting them, probably using gpg. That’ll let you set a password that is distinct from the one used for sudo or similar.
You should also be using full disk encryption to reduce the risk of a temporary file being exposed, or even overwritten sectors/pages being available to an attacker.
I’ve failed tremendously in making my demands come across :P .
Uhmm…, what you propose with gpg definitely solves one part of the puzzle.
But, if I understood correctly, it doesn’t help to prevent a disk clone from getting hold of the files.
Yes, the files are encrypted, but that’s not sufficient for my needs by itself. If the files would somehow destroy or corrupt themselves on a disk clone (or something to that effect), I would have acquired what I’m seeking.
Nothing can prevent a disk clone cloning the data, and there’s no way to make something happen when a disk is cloned as you’re not in control of the process.
If you wish to mask the existence of the files, use either full disk encryption, in which case cloning the disk doesn’t reveal the existence of the files without the decrypt password, or use a file based encrypted partition such as veracrypt in which case the cloner would just see a single encrypted blob rather than your file names.
Ultimately encrypting the files with gpg means they have already effectively ‘destroyed or corrupted’ themselves when cloned. If you don’t want to reveal the filenames, just call them something else.
If you could be a bit more specific about your threat model people may have better ideas to help.
If you could be a bit more specific about your threat model people may have better ideas to help.
Threat model is me protecting myself from myself.
Incoming XY problem.
I want to prevent myself from reinstalling my system. The trick I came up with involved the use of files that couldn’t be disk cloned. However, if it’s far far easier to accomplish it through other means, then please feel free to enlighten me on this.
If you don’t want files to be accessible by you, then have another user own them.
If you don’t want files to be accessible by root, then don’t have them at all.
This seems interesting. However, if I’m correct. What you suggest is not capable (by itself) to prevent said files to be copied through a disk clone. Am I right? Even if they’re otherwise encrypted or inaccessible, then still they will come through the disk clone. Did I understood you correctly?
What’s your end goal here? You try to keep files just on that one media without any options to make copies of them? Or maintain an image which has enforced files at their directories? And against what kind of scenarios?
ACLs and SELinux aren’t useful as they can be simply bypassed by using another installation and overriding those as root, same thing with copying. Only thing I can think of, up to a degree, is to use immutable media, like CD-R, where it’s physically impossible to move files once they’re in place and even that doesn’t prevent copying anything.
What’s your end goal here?
Incoming XY problem.
I want to prevent myself from reinstalling my system. The trick I came up with involved the use of files that couldn’t be disk cloned. However, if it’s far far easier to accomplish it through other means, then please feel free to enlighten me on this.
You try to keep files just on that one media without any options to make copies of them?
Yes.
Or maintain an image which has enforced files at their directories?
No, not necessarily.
And against what kind of scenarios?
Protecting myself from myself. That’s where the password requirement comes in: I can send a delayed message to myself that holds the password. The end result shouldn’t in the absolute sense prevent full access for always. Unlocking the protection should be possible and should require the involvement of the earlier mentioned password that is received through a delayed message. That way, those files can be accessed eventually, but only after I had intended to.
ACLs and SELinux aren’t useful as they can be simply bypassed by using another installation and overriding those as root
Excellent! I didn’t know this. Thank you for clarifying this for me!
Only thing I can think of, up to a degree, is to use immutable media, like CD-R, where it’s physically impossible to move files once they’re in place and even that doesn’t prevent copying anything.
The files should remain on the same disk that I run my OS from. So, unfortunately, this doesn’t quite help me. Thank you regardless!
I want to prevent myself from reinstalling my system.
Any even remotely normal file on disk doesn’t stop that, regardless of encryption, privileges, attributes or anything your running OS could do to the drive. If you erase partition table it’ll lose your ‘safety’ file too without any questions asked as on that point the installer doesn’t care (nor see/manage) on individual files on the medium. And this is exactly what ‘use this drive automatically for installation’ -option does on pretty much all of the installers I’ve seen.
Protecting myself from myself.
That’s what backups are for. If you want to block any random usb-stick installer from running you could set up a boot options on bios to exclude those and set up a bios password, but that only limits on if you can ‘accidently’ reinstall system from external media.
And neither of those has anything to do on read/copy protection for the files. If they contain sensitive enough data they should be encrypted (and backed up), but that’s a whole another problem than protecting the drive from accidental wipe. Any software based limitation concerning your files falls apart immediately (excluding reading the data if it’s encrypted) when you boot another system from external media or other hard drive as whatever solution you’re using to protect them is no longer running.
Unless you give up the system management to someone else (root passwords, bios password and settings…) who can keep you from shooting yourself on the foot, there’s nothing that could get you what you want. Maybe some cloud-based filesystem from Amazon with immutable copies could achieve that, but it’s not really practical on any level, financial very much included. And even with that (if it’s even possible in the first place, I’m not sure) if you’re the one holding all the keys and passwords, the whole system is on your mercy anyways.
So the real solution is to back up your files, verify regularly that backups work and learn not to break your things.
What do you mean with “displace”?
I guess you can use ACLs depending on your filesystem, or SELinux user contexts.
You can read about SELinux here or ACLs here. SELinux can be pretty complex if you’ve never used it, so make sure you understand it well. I believe it should be able to do what you want to achieve.
