[systemd-devel] Unprivileged user can kill root-owned processes by changing PID file and stopping service

[Reindl Harald]

Am 19.02.21 um 21:05 schrieb Frank Thommen:
> 
>> Lennart Poettering <lennart at poettering.net> hat am 19.02.2021 15:44 geschrieben:
>>
>>   
>> On Fr, 19.02.21 15:12, Frank Thommen (systemd-devel at lists.drosera.ch) wrote:
>>
>>> Dear all,
>>>
>>> I am experiencing the issue, that an unprivileged user can kill
>>> root-owned processes by changing a service's PIDFile.
>>
>> The file referenced by PIDFile= should not be under control of an
>> unpriv user.
>>
>> v219 is more than 5 years old. Since then we have tightened controls:
> 
> I am aware of this, but unfortunately for the time being we are stuck with this version (CentOS 7.4)

i yet need to see a real world usecase which needs "PIDFile=" at all - 
systemd kills everything in the cgroup anyways at stop

i even start mariadb with --pid-file=/dev/null and without "mysqlsafe" 
for years to get rid of all that shit

not a single service is using "PIDFile=" for years here and frankly i 
even forked systemd units only to get rid of that nosense from the 1990s