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How to Crash Systemd in One Command

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Re: How to Crash Systemd in One Command

#81

Post by kefka »

korethr wrote: post #49
namecast wrote: post #22

Earlier quoted context omitted.

I strongly disagree. I didn't need anyone to "show up" to replace my init system in production across several thousand servers, and the way systemd "won" that battle wrt Debian was, to be polite, controversial, political and extremely divisive. They sure as heck didn't win because "they showed up and no one else did". They showed up and RedHat's money showed up with them. I hold no animus towards the systemd project'…

> I hold no animus towards the systemd project's goals or aspirations, but I have yet to hear a compelling reason for systemd to be shipping in it's current state. I am, in a way, reminded reminded of PulseAudio. I kept PA of my desktop and laptop for years, having heard about PA being a complex nightmare to configure and make work that caused audio to break. Eventually, there was an application I needed to use that…

With PulseAudio, I have 1 singular feature that makes most people wow:

When I plug in any new audio device, whatever I'm playing/recording automatically sinks to the most recent device. Seamlessly. So if I'm on mail.google.com and a GVoice call comes in, I can take the call, and during the call, plug in my USB headset.

It just works.

Mac can't do that. Windows can't do that. Linux/PulseAudio can. And that kicks ass.

Re: How to Crash Systemd in One Command

#82

Post by xaduha »

Don't really care about that bug, it will be fixed I'm sure. But thank you for this post anyway, the word LLMNR caught my eye, very nice to have if it works.

EDIT: works fine with Windows, without installing Bonjour/iTunes.

Re: How to Crash Systemd in One Command

#84

Post by falcolas »

bitmapbrother wrote: post #69

>Despite the banality, the bug is serious, as it allows any local user to trivially perform a denial-of-service attack against a critical system component. Is it really that serious of a bug? You have to be a local user in order to execute it. Are other OS's somehow resilient to the actions of local user to degrade the OS? >The Linux ecosystem has fallen behind other operating systems in writing secure and robust sof…

Any remote code execution bug can exploit this. Normally, a remote execution code bug when the user is non-root isn't a huge issue, because the user effectively sandboxes them away. This bypasses all of these benefits.

Containers may prove to be a sufficient sandbox, assuming this is not executable against kdbus (which is shared across containers since it's in the kernel).

Re: How to Crash Systemd in One Command

#85

Post by regularfry »

georgyo wrote: post #58
fapjacks wrote: post #41

Earlier quoted context omitted.

The one thing that is painfully obvious about the situation with init systems is that people have strong opinions about their preferences. And that makes the systemd situation even more terrible, since it's a choice unwillingly foisted upon a huge number of people. This situation really deserves some choices. For me, that is the number one reason I do not like systemd, even if it's solved some problems.

I agree with your reason, however for me they get outweighed by other factors. If I am a maintainer of a popular distribution, I want my distro to have the best init system, and I want that init system to have the largest user base. EL6 and its derivatives was upstart, debian and its derivatives was upstart. The vast majority of linux systems were upstart for a long period of time. Other systems did not switch to ups…

That's not my recollection. Upstart was an Ubuntu project, Debian never adopted it. Red Hat picked up upstart, then Poettering managed to convince them that they'd be better off with one they controlled. Somehow that filtered back through to Debian, and they jumped straight to systemd from sysvinit.

At no point was it necessary for systemd to actually be better than upstart at being an init system. It just had to be bigger by the time it got to Debian.

Re: How to Crash Systemd in One Command

#86

Post by SysArchitect »

packetized wrote: post #44

Erm, this does not actually seem to work on Centos7, running systemd-219-19.el7_2.13. Even tried it as root inside of a sandbox - nothing.

  while true; do NOTIFY_SOCKET=/run/systemd/notify systemd-notify ""; done
Try this. As soon as you loop it, the bug is hit pretty quickly.

Re: How to Crash Systemd in One Command

#87

Post by agwa »

packetized wrote: post #44

Erm, this does not actually seem to work on Centos7, running systemd-219-19.el7_2.13. Even tried it as root inside of a sandbox - nothing.

Hmmm... I've repro'd on v215, v229, and v230, although only on Debian and Ubuntu. The bug has been in systemd upstream since v209 as far as I can tell by reading the code.

Re: How to Crash Systemd in One Command

#88

Post by dijit »

kefka wrote: post #81
korethr wrote: post #49

Earlier quoted context omitted.

> I hold no animus towards the systemd project's goals or aspirations, but I have yet to hear a compelling reason for systemd to be shipping in it's current state. I am, in a way, reminded reminded of PulseAudio. I kept PA of my desktop and laptop for years, having heard about PA being a complex nightmare to configure and make work that caused audio to break. Eventually, there was an application I needed to use that…

With PulseAudio, I have 1 singular feature that makes most people wow: When I plug in any new audio device, whatever I'm playing/recording automatically sinks to the most recent device. Seamlessly. So if I'm on mail.google.com and a GVoice call comes in, I can take the call, and during the call, plug in my USB headset. It just works. Mac can't do that. Windows can't do that. Linux/PulseAudio can. And that kicks ass.

Mac absolutely can do that, I'm not sure why you think it can't, perhaps it couldn't in the past.

I do it almost daily when I come home and plug in my Bose Companion 5 into my Macbook (USB Speakers)

Re: How to Crash Systemd in One Command

#89

Post by merb »

korethr wrote: post #49
namecast wrote: post #22

Earlier quoted context omitted.

I strongly disagree. I didn't need anyone to "show up" to replace my init system in production across several thousand servers, and the way systemd "won" that battle wrt Debian was, to be polite, controversial, political and extremely divisive. They sure as heck didn't win because "they showed up and no one else did". They showed up and RedHat's money showed up with them. I hold no animus towards the systemd project'…

> I hold no animus towards the systemd project's goals or aspirations, but I have yet to hear a compelling reason for systemd to be shipping in it's current state. I am, in a way, reminded reminded of PulseAudio. I kept PA of my desktop and laptop for years, having heard about PA being a complex nightmare to configure and make work that caused audio to break. Eventually, there was an application I needed to use that…

Well without production testing a product can never mature. It just depends how fast things will get shipped and fixed.

Re: How to Crash Systemd in One Command

#90

Post by Daviey »

justin_vanw wrote: post #65
sp332 wrote: post #60

Earlier quoted context omitted.

Didn't upstart and launchd cover this before systemd?

I don't know launchd, but upstart was a piece of crap that didn't even implement it's own documented functionality.

"piece of crap" really isn't fair. It powered many Ubuntu releases and Red hat 6. I liked upstart.
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