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I did this! I didn't actually know that Mint had enabled this by default. That would have been a useful counterpoint to the naysayers. If you want the origina

by timhh 6mo ago

I did this! I didn't actually know that Mint had enabled this by default. That would have been a useful counterpoint to the naysayers. If you want the original behaviour you don't actually need to change the configuration - they added a patch afterwards so you can press tab and it will hide the password just for that time. > The catalyst for Ubuntu’s change is sudo-rs Actually it was me getting sufficiently pissed off at the 2 second delay for invalid passwords in sudo (actually PAM's fault). There's no reason for it (if you think there is look up unix_chkpwd). I tried to fix it but the PAM people have this strange idea that people like the delay. So I gave up on that and thought I may as well try fixing this other UX facepalm too. I doubt it would have happened with the original sudo (and they said as much) so it did require sudo-rs to exist. I think this is one of the benefits of rewriting coreutils and so on in Rust - people are way more open to fixing long-standing issues. You don't get the whole "why are you overturning 46 years of tradition??" nonsense. If anyone wants to rewrite PAM in Rust... :-D https://github.com/linux-pam/linux-pam/issues/778 https://github.com/linux-pam/linux-pam/issues/778

yonatan8070 6mo ago
Pretty sure the 2s delay is designed to slow down brute-forcing it.
- timhh 6mo ago
  Not for local password authentication. https://github.com/pibara/pam_unix/blob/master/unix_chkpwd.c#L105-L112 https://github.com/pibara/pam_unix/blob/master/unix_chkpwd.c...
  - onraglanroad 6mo ago
    Yes, for local password authentication. The code you linked to isn't the code for a wrong password. It's a check to make sure you're using a TTY. That code isn't to prevent brute force. The delay there is 10 seconds. The 2 second delay is in support.c at https://github.com/pibara/pam_unix/blob/5727103caa9404f03ef04797dd581a5b7c87886b/support.c#L600 https://github.com/pibara/pam_unix/blob/5727103caa9404f03ef0... It only runs if "nodelay" is not set. But you might have another pam module setting its own delay. I have pam_faildelay.so set in /etc/pam.d/login Change both the config files and you can remove the delay if you want.
    - timhh 6mo ago
      > Yes, for local password authentication. It's really really not. By default PAM has a difficult-to-disable 2ish second minimum delay for all authentication methods. However this is completely pointless for local password authentication because PAM checks password using unix_chkpwd, which has no delay. The comment I linked to is explaining that unix_chkpwd has a silly security theatre delay if you try to run it in a tty, but that's trivial to avoid. If you want to brute force local password authentication you can just run unix_chkpwd as fast as you like. You don't need to involve PAM at all, so its 2 seconds delay achieves nothing. It maybe does more for remote connections but I'm not sure about that either - if you want to check 10k ssh passwords per second what stops you making 10k separate connections every second? I don't think the 2 second delay helps there at all. > Change both the config files and you can remove the delay if you want. This is extremely complicated. See the comments in the issue for details.
      - onraglanroad 6mo ago
        No, it's very simple. Do what I said in my comment. Add nodelay to the options for pam_unix.so and set pam_faildelay.so delay=0 That's it. You didn't link to any issue and the weird mistakes and justifications you're making feels like arguing with an LLM. You obviously can't run unix_chkpwd against a local account without root.
        timhh 6mo ago
        > You obviously can't run unix_chkpwd against a local account without root. Wrong. At least check before you say something is obvious. > No, it's very simple. Even more wrong: https://github.com/linux-pam/linux-pam/issues/778#issuecomment-3233644079 https://github.com/linux-pam/linux-pam/issues/778#issuecomme... > feels like arguing with an LLM I could say the same about you, repeatedly and confidently asserting falsehoods.
        onraglanroad 6mo ago
        No, I'm right. You can't run unix_chkpwd against a local account without root because you won't be able to access /etc/shadow to get the hash. If you think you can, explain how. Otherwise you have to use the setuid version which won't let you run it directly. And I just removed the delay using my method. Perhaps try checking something yourself?
9dev 6mo ago
> If anyone wants to rewrite PAM in Rust... :-D If you do, offer support for writing modules in a scripting language like Lua or Python. PAM could make it a lot easier to just add OAuth with your company IdP, for example…
- tetha 6mo ago
  Ah, but then you choose the wrong language or language runtime and distros ship old versions for 10+ years :) (compare: polkit. Both sides have their point, but I've been annoyed by this standoff a few times).
egorfine 6mo ago
> You don't get the whole "why are you overturning 46 years of tradition??" nonsense Respectfully, we are the opposing sides of the barricades here. I was removing sudo-rs, uutils and some of the systemd-* packages from fresh Ubuntu installations until the amount of virtue signaling got really tiresome. Currently almost no Ubuntu left in my production. Hopefully Debian will not package those. PS: Rust is awesome!
1718627440 6mo ago
> There's no reason for it The reason is to add a delay when bruteforcing passwords.
- hananova 6mo ago
  Bruteforcing is only really done with the password hashes in hand. Attacks on live systems are done with credential stuffing.
- timhh 6mo ago
  Definitely not for local password authentication, and I'm dubious it helps for ssh either. See my other comment.

by timhh 6mo ago

yonatan8070 6mo ago

Pretty sure the 2s delay is designed to slow down brute-forcing it.

timhh 6mo ago
Not for local password authentication. https://github.com/pibara/pam_unix/blob/master/unix_chkpwd.c#L105-L112 https://github.com/pibara/pam_unix/blob/master/unix_chkpwd.c...
- onraglanroad 6mo ago
  Yes, for local password authentication. The code you linked to isn't the code for a wrong password. It's a check to make sure you're using a TTY. That code isn't to prevent brute force. The delay there is 10 seconds. The 2 second delay is in support.c at https://github.com/pibara/pam_unix/blob/5727103caa9404f03ef04797dd581a5b7c87886b/support.c#L600 https://github.com/pibara/pam_unix/blob/5727103caa9404f03ef0... It only runs if "nodelay" is not set. But you might have another pam module setting its own delay. I have pam_faildelay.so set in /etc/pam.d/login Change both the config files and you can remove the delay if you want.
  - timhh 6mo ago
    > Yes, for local password authentication. It's really really not. By default PAM has a difficult-to-disable 2ish second minimum delay for all authentication methods. However this is completely pointless for local password authentication because PAM checks password using unix_chkpwd, which has no delay. The comment I linked to is explaining that unix_chkpwd has a silly security theatre delay if you try to run it in a tty, but that's trivial to avoid. If you want to brute force local password authentication you can just run unix_chkpwd as fast as you like. You don't need to involve PAM at all, so its 2 seconds delay achieves nothing. It maybe does more for remote connections but I'm not sure about that either - if you want to check 10k ssh passwords per second what stops you making 10k separate connections every second? I don't think the 2 second delay helps there at all. > Change both the config files and you can remove the delay if you want. This is extremely complicated. See the comments in the issue for details.
    - onraglanroad 6mo ago
      No, it's very simple. Do what I said in my comment. Add nodelay to the options for pam_unix.so and set pam_faildelay.so delay=0 That's it. You didn't link to any issue and the weird mistakes and justifications you're making feels like arguing with an LLM. You obviously can't run unix_chkpwd against a local account without root.
      - timhh 6mo ago
        > You obviously can't run unix_chkpwd against a local account without root. Wrong. At least check before you say something is obvious. > No, it's very simple. Even more wrong: https://github.com/linux-pam/linux-pam/issues/778#issuecomment-3233644079 https://github.com/linux-pam/linux-pam/issues/778#issuecomme... > feels like arguing with an LLM I could say the same about you, repeatedly and confidently asserting falsehoods.
        onraglanroad 6mo ago
        No, I'm right. You can't run unix_chkpwd against a local account without root because you won't be able to access /etc/shadow to get the hash. If you think you can, explain how. Otherwise you have to use the setuid version which won't let you run it directly. And I just removed the delay using my method. Perhaps try checking something yourself?

9dev 6mo ago

> If anyone wants to rewrite PAM in Rust... :-D If you do, offer support for writing modules in a scripting language like Lua or Python. PAM could make it a lot easier to just add OAuth with your company IdP, for example…

tetha 6mo ago
Ah, but then you choose the wrong language or language runtime and distros ship old versions for 10+ years :) (compare: polkit. Both sides have their point, but I've been annoyed by this standoff a few times).

egorfine 6mo ago

> You don't get the whole "why are you overturning 46 years of tradition??" nonsense Respectfully, we are the opposing sides of the barricades here. I was removing sudo-rs, uutils and some of the systemd-* packages from fresh Ubuntu installations until the amount of virtue signaling got really tiresome. Currently almost no Ubuntu left in my production. Hopefully Debian will not package those. PS: Rust is awesome!

1718627440 6mo ago

> There's no reason for it The reason is to add a delay when bruteforcing passwords.

hananova 6mo ago
Bruteforcing is only really done with the password hashes in hand. Attacks on live systems are done with credential stuffing.
timhh 6mo ago
Definitely not for local password authentication, and I'm dubious it helps for ssh either. See my other comment.