How to crash systemd in one tweet

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How to crash systemd in one tweet

Postby jiml8 » Sep 29th, '16, 18:20

https://www.agwa.name/blog/post/how_to_ ... _one_tweet

I have not tried this; rebooting my system is something I avoid to the extent I can, and I am busy now so I don't want to have to do it.

The article brings up MANY excellent points regarding the negative impact of systemd on modern Linux systems.
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Re: How to crash systemd in one tweet

Postby doktor5000 » Sep 29th, '16, 19:04

So on the other hand, you don't think there are one-liners that could crash SysV init? And it's not like everything was golden back then ...

I tend to agree more with this comment
This article starts with a bug. Note, it's a pretty irrelevant one that doesn't appear to be reproducible on recent builds.

Then it brings up a few other debatable issues, and then it incorrectly generalizes that systemd security is terrible. I say debatable because for example parsing command line parameters isn't something people usually delegate to a separate process.

Unfortunately, it also ignores all the great systemd security features it has added for the average Linux user (such as private tmp, and cgroups), and in fact all the other great features it has.


FWIW, as this is also only mentioned in the comments, the command mentioned usually does nothing for recent versions.
See also the respective bug report https://github.com/systemd/systemd/issues/4234 (which the author of that article forgot to mention/report ...)
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Re: How to crash systemd in one tweet

Postby jiml8 » Sep 29th, '16, 20:01

And a subsequent comment to the comment you posted indicates that this isn't parsing text; it is accepting input from a world-available interface directly into PID 1 without validation or isolation.

Also, the subsequent comment points out that private tmp is not a systemd feature, and neither are cgroups. Further, cgroups are not intended as a security enhancement anyway, though they can be used that way.

Also, there was debate about whether it happened in recent versions. I still haven't tested it with M5 and don't really plan to unless I happen to have a copy other than my workstation running.

I don't know if there were 1-liners that could crash sysV init, but I do know that if sysV init crashed the system would die and restart gracefully because sysV init did nothing but start the system and scavenge zombies...unlike the current init which has become quite a heavyweight program.
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Re: How to crash systemd in one tweet

Postby nigelc » Oct 4th, '16, 13:25

I can make my system crash with it.

Code: Select all
NOTIFY_SOCKET=/run/systemd/notify systemd-notify ""
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