Persist /tmp permissions

Add to /etc/tmpfiles.d/tmp.conf to enforce correct perms

echo "d /tmp 1777 root root -" | sudo tee /etc/tmpfiles.d/tmp.conf

Or add to /etc/rc.local (if you use it)

echo "chmod 1777 /tmp" | sudo tee -a /etc/rc.local

Or create a systemd service to enforce it

sudo tee /etc/systemd/system/fix-tmp-perms.service <<'EOF'
[Unit]
Description=Ensure /tmp has correct permissions
After=local-fs.target

[Service]
Type=oneshot
ExecStart=/bin/chmod 1777 /tmp
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl enable fix-tmp-perms.service