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Top-level
 … you can easily turn it off via the --background= switch). It also inserts a red dot (unicode ftw) in the window title while you operate with privileges, and drops it afterwards. And since it's just systemd-run called under a different name it supports the --property= switch that systemd-run supports, i.e. it allows you to set arbitrary service settings for the invoked privileged command/session if you like. Anyway, that's all for now. Enjoy "run0"! 49 comments
@stephan not sure I grok what you are saying. run0 can invoke a shell as root for you, but can also invoke any other command you like as root. The shell is after all just a program too. A program that is typically used to invoke further programs, but still just a program. Regardless what you precisely invoke: run0 will tint the bg of its output (and your input) in a reddish tone. Once the program terminates this tinting ends, and you get your usual black (or white or whatever) background back. @pid_eins Yes that explains it. I kinda forget that running a shell is also just running a programm. Looking forward to run0.  @pid_eins wow the auto coloring and title changes would be really annoying. The config to disable it seems to be not user friendly, too: @amanzer @sszuecs oh. i didn't grok @sszuecs's comment, I was sure there was some misunderstanding but I couldn't figure out how! But your explanation explains the misunderstanding perfectly! So yes, the switch is called "--background=" and you can override the background color with that, or you can assign an empty string to disable the tinting altogether. @pid_eins, like https://gist.github.com/JBlond/2fea43a3049b38287e5e9cefc87b2124/da3a76d981e3ee95d00f14db07975e088a02a311#regular-colors? Why is that preferable to hex codes with alpha channels and all that goodness? @rokejulianlockhart because this is about terminal output, and terminals eat ansi sequences and have no concept of alpha channels? @pid_eins @rokejulianlockhart well, modern terminals have true color support at least... would've been nice over the plain ansi number but I get it that querying the cap might be annoying.
@pid_eins I think it's a good take one sudo. I think there were some vulnerabilities found in sudo recently, so it's good to look at other ways to do it. I wonder what the adoption of this tool is gonna be. Just very pragmatically, the name run0 is harder to type than sudo. So you would have to make a shell alias. Would it be possible for a distro to completely replace sudo with this and create an alias by default? Maybe it would need to get a compatibility mode for it to replace sudo @TheStroyer the command line of run0 is intentionally kept close to sudo's. But that's were the compatibility really ends, i.e. /etc/sudoers and so on we're never going to add compat for. From my perspective run0 should be fine already for a distro to replace sudo with. But let's see how this plays out, I am pretty sure there might be a feature or two we still need to add before the first distros decide it's ready to switch over. And I am pretty sure there are plenty of distributions… @TheStroyer … which think that things like pluggable client-side modules, LDAP and so on are actually a good thing, even though I would vehemently disagree with that.  @pid_eins Same disagreement here. But also iirc policykit is extensible right? So if someone is brave enough they could probably extend pk with whatever things they want, and then it can apply to all privilege escalation not just run0! Maybe I shouldn't give people ideas... @danderson PK is scriptable with JS, so people kinda can do any kind of shit with it, of course. But I think it's much less problematic than what sudo is doing, because PK runs that stuff in a well defined execution context forked off PK's service which runs unprivileged – and not on the client side, in an icky, undefined, half-inherited mess of an execution context under user control – like sudo does it. @pid_eins 100% yes. N:M dlopen() in unpredictable contexts should really go away as a plugin mechanism, it's so easy to create massive problems. I saw some distros try to fix PAM this way too, they (ab)use the nscd caching protocol in glibc to move all lookups into a system daemon, and hide the .so's from the rest of the system. Same idea, move all the scary plugin stuff to a central location where you can manage it more safely. @pid_eins Looks like there was a short discussion on the glibc ML in 2022 about formalizing this interface and explicitly support the privilege separation use case, but I'm not sure if anything more happened since... @danderson from my perspective as a systemd person I wouldn't ask for that from glibc. We have nss-systemd these days which is an IPC frontend to the generic varlink IPC API described here: https://systemd.io/USER_GROUP_API Anyone can plug in their stuff there. It's generic, extensible and IPC based. Unless you are a systemd hater I see no reason why we'd need to shove that into glibc. @pid_eins Ooh, TIL! I didn't know about this entire subsystem of systemd. My worry was going to be what to do with the cursed legacy modules that some people have, but I see with userdbd there's bidirectional compatibility between varlink and nss clients. Very nice, and yes I agree this is a better way to set up the system. I look forward to the posts for next release, I'm even learning stuff about older releases! @danderson @pid_eins if later systemd is not enough sssd has provided this service with proper caching for almost 15 years. It was built specifically for 3 reasons: consistent caching, remove unwanted libraries from binaries, allow centally controlled private credentials. Because it predates systemd it has its own protcol but also a fast, mmaped shared cache that avoid process context switching when not needed. (full disclosure I am the original author). @pid_eins So the intention for it to be a replacement for sudo right? I.e. sudo does not need to be present on a system.   > the command line of run0 is intentionally kept close to sudo's.
Could we get a -E/--preserve-env switch? (It'd also be nice if users can do per-user configuration to set that, or to set a variety of specific environment variable passthroughs.) There are a variety of environment variables that are useful to pass through, and I'd rather not specify them all every time or do configuration-via-shell-alias. @pid_eins How would one check, within a bash script, if it was executed with run0? @verbumfeit sudo sets a bunch of env vars, and we set the same (i.e. SUDO_UID/SUDO_GID/SUDO_USER), for compat. @pid_eins It sounds like a great improvement on sudo, but I have a question: how do you pronounce "run0"?  @NekkoDroid @bluca @pid_eins @smlx You know this logo (and the clip of “Forever Young” by Alphaville) are quite problematic in many nations, right? No I indeed don't know because I don't keep up with car companies and what they do. @mcepl, so? It's the symbol of a car manufacturer. That's the context it was being used in, and that's all that matters consequently. Ask some of your Central European or Eastern European friends. @Lioh We don't talk about run0! (https://youtu.be/bvWRMAU6V-c?si=UUIfTlbiiuIYm4vD) @irina we have been going forth and back on this internally, we are not going to reopen that can of worms, sorry. Its a bit bikesheddy at this point...  @pid_eins One request: _please_ also ship documentation (manpage, whatever, something easily findable) on how configure polkit/run0 to do common sudo patterns like "Allow wheel to do sudo -i with password". "Allow that user to run this _exact commandline_ without password; and this other command with any parameters". By now, I know how to do these things with sudoers, but a big barrier to using run0 at least for me would be having to learn all of those patterns in polkit. @pid_eins And also: "remember I typed my password five seconds ago" and "forcefully expire said knowledge". @pid_eins One thing I do with sudo is allow a less privileged app process to invoke an nspawn container to run a sandboxed command. But the command is only known at runtime. I wonder if there would be any way to do that with run0.  Very interesting ! On some servers I configured sudo in order *not* to allow to run for instance : sudo bash, or sudo sh, or sudo su by the way. Is this kind of control possible ? I must admit last time I touched polkit was decades ago. |
Gregory's Server
@pid_eins When you say "while you are operating with elevated privileges", do you mean you can use run0 to create a root shell to work in, or do you just mean while the current programm I started as run0 ist running?