Why sysrq is limited to only "sync" command on official fedora kernel?

Zdenek Kabelac zkabelac at redhat.com
Wed Feb 25 20:38:36 UTC 2015

Dne 25.2.2015 v 18:44 Reindl Harald napsal(a):
> Am 25.02.2015 um 18:37 schrieb Paul Wouters:
>> On Wed, 25 Feb 2015, Lennart Poettering wrote:
>>> Hmm? Syncing is allowed to my knowledge. C-a-d and gdm allow a clean
>>> reboot/poweroff. But sysrq does an abnormal reboot/poweroff, which we
>>> cannot allow. Similar, remounting read-only is also security senstive,
>>> which we cannot allow.
>>> Without being logged in there's very little you can do on a host right
>>> now, and sysrq should not open up more there by default.
>> You must have forgotten your university days....
>> The alternative to not being able to sync-umount-boot using sysrq is to
>> flip the switch. I'd rather have them use sysrq.
>> I said it when they closed X ctrl-alt-backspace and I'll say it now.
>> When you are on console with the power plug, preventing these actions
>> is stupid
> when you are on a machine where you have pysical only keyboard and mouse it is
> not - not every PC stands in front of your face - think about kiosk mode and
> so on...

When I read such answers - I always wonder myself - how many kiosk ever run 

It's such a bad idea to optimize Fedora for one-in-milion users and those 
999.999 has to suffer instead of require 1 guy to configure more secure version.

On the other hand - Fedora might easily provide a 'script' to disable all 
obscure 'security' settings - if that's the only thing to pass the security 
audit with 'defaults'...

And my recent personal experience - I tried to configure NFS to use it between 
my qemu and host machine - and guess what - first thing which has been 
instantly removed from host was firewalld as this piece is simply 
unconfigurable nonsense and the second one is absurdly broken nfs4 - replaced 
with usable nfs3...

People need to do their works and don't have time to spend ours figuring out 
where the settings has been shifted after some security-person decisions and 
systemd upgrades....



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