So I have a server running openssh 8
[root@jnode-fw15 ~]# rpm -qa |grep -i openssh
openssh-clients-8.0p1-12.el8.x86_64
openssh-askpass-8.0p1-12.el8.x86_64
perl-Net-OpenSSH-0.80-1.el8.noarch
openssh-server-8.0p1-12.el8.x86_64
openssh-8.0p1-12.el8.x86_64
The server has an open multiplex session connected (ips replaced)
[root@jnode-fw15 ~]# ll /tmp/wk-d0307-node-a_23
srw------- 1 cyc cyc 0 Dec 26 19:40 /tmp/wk-d0307-node-a_23
[root@jnode-fw15 ~]# ps -ef |grep /tmp/wk-d0307-node-a_23 |grep mux
cyc 3748383 1 0 19:40 ? 00:00:00 ssh: /tmp/wk-d0307-node-a_23 [mux]
[root@jnode-fw15 ~]# lsof -i -nP |grep 3748383
ssh 3748383 cyc 3u IPv4 130530051 0t0 TCP xx.xx.xx.xx:57556->xx.xx.xx.xx:23 (ESTABLISHED)
However, running a check to this master, the session just hangs:
[root@jnode-fw15 ~]# date; timeout 10 ssh -v -p 23 -o controlpath=/tmp/wk-d0307-node-a_23 check ls ; date
Mon Dec 26 20:28:51 IST 2022
OpenSSH_8.0p1, OpenSSL 1.1.1k FIPS 25 Mar 2021
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug1: configuration requests final Match pass
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
Mon Dec 26 20:29:01 IST 2022
Narrowing down the problem further, the master was created like this:
root@jnode-fw15~ $ ssh -p23 -o controlmaster=yes -o controlpath=/tmp/wk-d0307-node-a_23 -o controlpersist=1200 -o ConnectTimeout=10 -2 -o ServerAliveInterval=10 wk-d0307-node-a_23 echo
I believe that when we pass the controlpersist timeout, the master does not shut down after it times out, the problem is that it stops replying at all
It's even impossible to shut it down:
[root@jnode-fw15 ~]# ssh -v -O exit -o controlpath=/tmp/wk-d0307-node-a_23 wk-d0307-node-a_23
OpenSSH_8.0p1, OpenSSL 1.1.1k FIPS 25 Mar 2021
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug1: configuration requests final Match pass
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
any ideas?
