[SOLVED] KUbuntu hangs for ~2 minutes after login

[adepoula]

Hello after doing a fresh install of KUbuntu 24.04.1, I am experiencing an issue after submitting my password on the login screen which might be connected to SDDM or plasma, I'm not sure.
After submitting my password, my screen becomes black and I can only move the mouse cursor. I have to wait between 2 and 3 minutes until something times out, and then the desktop shows up.

This weird behavior appears after I run a script provided by my company to harden the security of my laptop which modified the rsyslog configuration and add some iptables rules:

#!/bin/bash

echo "#!/bin/bash

iptables -F
iptables -P INPUT DROP

iptables -N LOG_DROP
iptables -A LOG_DROP -j LOG --log-prefix '[IPTABLES DROP] : '
iptables -A LOG_DROP -j DROP

iptables -N LOG_ACCEPT
iptables -A LOG_ACCEPT -j LOG --log-prefix '[IPTABLES ACCEPT] : '
iptables -A LOG_ACCEPT -j ACCEPT

ip6tables -N LOG_ACCEPT
ip6tables -A LOG_ACCEPT -j LOG --log-prefix '[IPTABLES ACCEPT] : '
ip6tables -A LOG_ACCEPT -j ACCEPT

iptables -A INPUT -i lo -j ACCEPT

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j LOG_ACCEPT

iptables -A INPUT -j LOG_DROP
iptables -A FORWARD -j LOG_DROP

ip6tables -F INPUT
ip6tables -F OUTPUT
ip6tables -F FORWARD
ip6tables -F

# Allow ICMP
#ip6tables -A INPUT -p icmpv6 -j ACCEPT
ip6tables -A INPUT -m state --state ESTABLISHED,RELATED -j LOG_ACCEPT
ip6tables -P INPUT DROP" > /etc/init.d/firewall

chmod +x /etc/init.d/firewall
#update-rc.d firewall defaults
#/etc/init.d/firewall

echo "[Unit]
Description=Packet Filtering Framework
DefaultDependencies=no
After=systemd-sysctl.service
Before=sysinit.target
[Service]
Type=oneshot
ExecStart=/etc/init.d/firewall
ExecReload=/etc/init.d/firewall
ExecStop=/etc/init.d/firewall
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target" > /etc/systemd/system/iptables.service

systemctl enable iptables
systemctl start iptables

​

If I disable the iptables service, or enable it without the rules, everything is working fine, my desktop shows up right after I submit my password. Hence, I suspect that the issue is related to my iptables configuration but I cannot find why.
In addition, I didn't have the problem with Kubuntu 22.04.

Here is the output of the journalctl entries related to x11. We can see that after more than 2 minutes, systemd tries to launch plasmax11:

$ sudo journalctl -xb | grep -i startplasma-x11
sept. 25 15:07:10 pc sddm[1214]: Session "/usr/share/xsessions/plasma.desktop" selected, command: "/usr/bin/startplasma-x11" for VT 2
sept. 25 15:07:10 pc sddm-helper[1414]: Starting X11 session: "" "/etc/sddm/Xsession \"/usr/bin/startplasma-x11\""
sept. 25 15:09:25 pc systemd[1417]: Reloading requested from client PID 1460 ('startplasma-x11')...

Do you have any idea what could cause this wait of ~2 minutes?

[zahtar]

Same issue for me, it started occurring when I installed NordVPN and its plasmoid through Discover. I have removed them but the problem persists. Any ideas? If I can provide any useful info, please let me know. Thanks in advance!

[MarcZ]

I also share this delayed login experience. Disabling my iptables firewall eliminated the problem, I'm not sure how to modify the firewall to fix this and I cannot leave the firewall down, so I guess I have to live with this

[adepoula]

I also share this delayed login experience. Disabling my iptables firewall eliminated the problem, I'm not sure how to modify the firewall to fix this and I cannot leave the firewall down, so I guess I have to live with this

After several tests, I was able to finally find a solution. I just added the following rule to fix the issue:

ip6tables -A INPUT -i l0 -j ACCEPT

[zahtar]

I tried to look this up, but I do not understand what this command does. How does it work? Does it affect security in any way?

Thanks in advance.