4 ms·
You can also do this: sudo fdesetup authrestart -delayminutes -1 which will make the computer auto login to the chosen account on next reboot, without havi
by varenc 1y ago
You can also do this:
sudo fdesetup authrestart -delayminutes -1
which will make the computer auto login to the chosen account on next reboot, without having to type in a password. Only lasts once. Has obvious security downsides though but that might be fine.
- eastbound 1y agoBut then you could just disable FileVault?
- derefr 1y agoI think the point of this technique is to be able to leave the machine locked on cold boot, but to be able to e.g. unlock it, put it to sleep, and go on vacation; and then, if you need to remotely reboot it, you can reboot it in such a way that it stays unlocked on next boot, rather than reverting to locked.
- kkylin 1y agoGenerally I have used fdesetup to do remote OS upgrades: do this just before an OS upgrade so that on reboot I can still log in.
- anyfoo 1y agoIt's still a little bit like putting your jewelry in a safe, and leaving the key on top of the safe.
- derefr 1y agoI mean, I assume you'd set the unlock-on-reboot flag, and then immediately reboot — at which point the unlock-on-reboot flag gets automatically unset. So, sure, it's a bit like leaving the key on top of the safe... while you have the safe open. Which isn't all that odd.
- anyfoo 1y agoNo, the scenario was power outage at an unknown time in the future, not immediate reboot.
- BHSPitMonkey 1y agoWhen it comes to disk encryption, at least in the home, the threat model isn't somebody sitting around in your home finding a way to exfiltrate the currently-unlocked filesystem; It's someone taking the computer or the drive with them and leaving. In your analogy, the key atop the vault vanishes as soon as the vault is moved from its location (loses power).
- anyfoo 1y agoIf that was the case (maybe it is, I don’t know), then how does the proposed solution help against power outages, which was asked for?
- avianlyric 1y agoThat wasn’t what was asked for. The original reason given was to require a password on cold boot, but not require a password when rebooting e.g. for an OS update
- anyfoo 1y agoWell, you've asked me to quote in another subthread, I did. Since I don't fully get what you're referring to now, can you please quote?
- patrakov 1y agoIt makes sense temporarily. You can always move the key to your pocket later if nobody steals it.
- anyfoo 1y agoOh yeah, I get it. Just pointing out what this is doing, and why you should probably not always do this, for example.
- johncolanduoni 1y agoThis only puts the key in NVRAM until the next restart - so if you run it just before you restart an attacker would have to happen to grab the device in those few minutes.
- anyfoo 1y agoThe stated problem was power outages. I did not verify the syntax of the proposed solution, but -1 looks like it disables the delay. So, indefinitely until the next reboot? Which, if the key is indeed saved in NVRAM (I don’t know), means someone can take the machine and have it unlocked at their destination.
- johncolanduoni 1y agoIt used to be NVRAM at least, but that was before the integrated Secure Enclave. Now it could in theory store it there and only unlock if the boot chain is validated (similar to the automatic TPM-based unlock that Windows uses by default).
- anyfoo 1y agoRight, but my point was, if the idea is to do this to have an automatic unlock on power outages (and if this persists across power outages), it’s not just a few minutes, it’s indefinitely.
- avianlyric 1y agoYou’re going to have to quote that the stated problem was power outages. The first comment in this thread was taking about how the linked article solves the power outage problem. But the sub-thread about using the existing utils is only for solving the unlock on reboot problem, and explicitly not solving the cold boot unlock problem.
- anyfoo 1y agoFirst comment: > So you're saying i can now have a fully remote mac mini server with auto-reboot on power outage without the need to physically log ... Reply: > You can also do this: [...] -delayminutes -1 [...] which will make the computer auto login to the chosen account on next reboot, without having to type in a password. Only lasts once. Has obvious security downsides though but that might be fine. Even though I haven't checked, the "-delayminutes -1" very much sounds to me like it disables the automated reboot, so it waits until the machine reboots for other reasons. Given this and given that it is a direct reply, I personally took it as another solution to the power outage problem, the "reboot" in question actually being a cold boot due to the power outage. Note that I haven't verified whether this works after removing power.
- firecall 1y agoI was also aware of this - but I dont want my Mac to actually auto login, for obvious reasons! I just want me to able to remotely login!
- varenc 1y agoYou could have another script that immediately triggers the Lock Screen after boot...but agreed this comes with many compromises. But if your Mac is physically secure, and has no keyboard or monitor on it anyway, I don't quite understand the risk? Remote login still requires the password after this of course. But if physical security is a concern it makes sense. Also I suppose there's other risks from having a decryption key sitting in NVRAM.