Linux @lemmy.ml starman @programming.dev 6 mo. ago

Systemd wants to expand to include a sudo replacement

outpost.fosspost.org Systemd wants to expand to include a sudo replacement

Systemd lead developer Lennart Poettering has posted on Mastodon about their upcoming v256 release of Systemd, which is expected to include a sudo replacem...

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Linux @programming.dev starman @programming.dev 6 mo. ago

Systemd wants to expand to include a sudo replacement

outpost.fosspost.org /d/19-systemd-wants-to-expand-to-include-a-sudo-replacement

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- Agreed, this is a nice inclusion. I also hate sudoers with a passion - I already use doas but it's not standard (in the Linux world anyway), but with systemd providing an alternative means that it'll become a standard which most distros would adopt, and I hope this means we can finally ditch the convoluted sudoers file once and for all.
  
  How does doas differ from sudo?
  
  Never heard of the former until now.
  
  doas is quite popular in the BSD world, and was ported to Linux a few years ago (via the OpenDoas project).
  
  For starters, it's is a lot smaller than sudo - under 2k lines of code vs sudo's 132k - this makes it lot more easier to audit and maintain, and technically less likely to have vulnerabilities.
  
  Another security advantage is that doas doesn't pass on the environment variables by default (you'd have to explicitly declare the ones you want to pass, which you can do so in the config).
  
  The config is also a lot simpler, and doesn't force you to use visudo - which never made sense to me, visudo should've just generated the actual config, instead of checking it after the fact. Kinda like how grubby or grub2-mkconfig works. But no need for that complexity with doas.
  
  Eg, the most basic doas config could just have one line in the file: permit: wheel. Maybe have another line for programs you want to run without a password, like permit nopass dexter cmd pacman.
  
  Awesome. Thanks for the insight.
  
  Essentially functionally stripped sudo, smaller in size than sudo. See also Pottering's thoughts about the ecosystem
  
  Nice to see that Mastodon has the same problem as Twitter with people trying to use it for long-form blog posts for some godforsaken reason.
  
  Makes sense considering people who moved from one micro-blogging service to another instead of giving up on the idea completely are probably the ones deeply committed to that flawed idea.
  
  Blame the Mastodon team, if you're not running a fork, you have to go into the source and adjust the character limit manually.
  
  Nobody has to do it like this, Mastodon supports longer posts since other servers and clients support more, it's seemingly just a choice from upstream.
  
  I admit, I’m not a big fan of putting more functionality into systemd (or just of systemd in general), but that is a well-reasoned argument for having sudo live in the init system.
  
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  The thing with this is: its just a symlink to the systemd-run binary, which talks to PID1 to spawn new processes (in separate cgroups IIRC). Its one of the most fundamental parts of systemd. Even the debian systemd package includes systemd-run.
  
  I guess the other question is if some tools the distro provides might switch to supporting it by default. For example on Arch there is makepkg that should never be executed as root, but does internally call some things with elevated privileges (mostly pacman to install and remove packages). Currently it checks for sudo and if not falls back to su, but maybe it might be worth considering changing su for run0 if its guaranteed to be there.
  
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  it does its authorization with polkit (which IIRC defaults to allow all wheel group members) and giving users that shouldn't be allowed root access, root access, is not something you ever want. This is usually referred to as unauthorized privilege escalation. Also, it isn't like sudo doesn't need configuration.
- I read the original mastodon post by the developer of run0 and I am still don’t understand what the problem with SUID is.
  
  Whats an example of an attack that would work with sudo and doas (which also uses SUID) and not on run0?
  
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  Thanks for taking the time to explain. I was trying to get my head around on how this works but could not understand much of it. A lot of people here are very much against systemd in all senses, but this sounds like a better approach. Even if it not done as systemd, makes more sense than checking files and getting elevated privileges for a scope and use guardrails everywhere

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