Bug 785874

Summary:	net-misc/openssh: sshd.service should include KillMode=process
Product:	Gentoo Linux	Reporter:	Roy Yang <cdyhaj799>
Component:	Current packages	Assignee:	Gentoo's Team for Core System packages <base-system>
Status:	RESOLVED FIXED
Severity:	normal	CC:	sam, systemd
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Roy Yang 2021-04-26 19:46:26 UTC

When restart sshd service, KillMode sprecifys which mode the process is supposed to be killed. See https://www.freedesktop.org/software/systemd/man/systemd.kill.html

By default, It will kill all process in control-group, that is, main process and its forked ones. This is not desirable in practice. Usually, developers expect his session still remains.

Also investigated the other distros, KillMode=process is prefered.

Reproducible: Always

Steps to Reproduce:
1.ssh machineA
2.sudo systemctl restart sshd

Actual Results:  
Current ssh session is dropped

Expected Results:  
Expected sshd is restarted, but current ssh session remains.

Comment 1 Roy Yang 2021-04-26 20:02:04 UTC

Submit a CL: https://github.com/gentoo/gentoo/pull/20551

Comment 2 Mike Gilbert gentoo-dev

2021-04-26 20:11:34 UTC

> Actual Results:  
> Current ssh session is dropped

That should not happen, regardless of the KillMode setting in the service unit.

pam_systemd should move the session to a separate scope, which will prevent the session sshd from being killed.

Do you have PAM disabled? If so, I suggest you enable it for proper SSH session management.

Comment 3 Mike Gilbert gentoo-dev

2021-04-26 20:21:20 UTC

Anyway, I guess changing the KillMode won't hurt anything. I'll merge it.

Comment 4 Larry the Git Cow gentoo-dev

2021-04-26 20:23:31 UTC

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=28ae62f0ee4f0fc34987713043a036d581e4a3e8

commit 28ae62f0ee4f0fc34987713043a036d581e4a3e8
Author:     Roy Yang <royyang@google.com>
AuthorDate: 2021-04-26 19:50:42 +0000
Commit:     Mike Gilbert <floppym@gentoo.org>
CommitDate: 2021-04-26 20:22:33 +0000

    net-misc/openssh: Add KillMode=process to sshd.service
    
    Closes: https://bugs.gentoo.org/785874
    Closes: https://github.com/gentoo/gentoo/pull/20551
    Signed-off-by: Roy Yang <royyang@google.com>
    Signed-off-by: Mike Gilbert <floppym@gentoo.org>

 net-misc/openssh/files/sshd.service | 1 +
 1 file changed, 1 insertion(+)