a982995d5b
The unit has NoNewPrivileges=true (security hardening for srcds), which blocks sudo's setuid escalation. The previous sudo'd ExecStartPre failed on every start with "sudo: the 'no new privileges' switch is set, which prevents sudo from running as root" -> Restart=on-failure loop. systemd's `+` prefix runs the Exec command as PID 1 (root, no sandbox), bypassing User=/Group=/NoNewPrivileges=. Equivalent privilege scope to the sudoers rule the web app already uses for the same helper, just without the sudo middleman. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
64 lines
2.4 KiB
Desktop File
64 lines
2.4 KiB
Desktop File
[Unit]
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Description=left4me server instance %i
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After=network-online.target
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Wants=network-online.target
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[Service]
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Type=simple
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User=left4me
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Group=left4me
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EnvironmentFile=/etc/left4me/host.env
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EnvironmentFile=/var/lib/left4me/instances/%i/instance.env
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# `-` prefix: chdir failure is non-fatal. systemd applies WorkingDirectory
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# before every Exec line — including ExecStartPre — but the merged dir only
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# exists once ExecStartPre's overlay mount succeeds. With `-`, ExecStartPre
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# runs in the unit's home (cwd doesn't matter for the mount helper); the
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# ExecStart re-applies WorkingDirectory after the mount and finds the dir.
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WorkingDirectory=-/var/lib/left4me/runtime/%i/merged/left4dead2
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# Single source of truth for the kernel-overlayfs mount: the web app's
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# start_instance only stages cfg files and asks systemd to enable+start
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# this unit; the actual `mount -t overlay` lives here so reboot auto-start
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# works the same as a UI-driven start. Helper is idempotent.
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#
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# `+` prefix runs the helper as PID 1 (root, no sandbox). Required because
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# the unit has NoNewPrivileges=true, which blocks sudo's setuid escalation
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# — and the helper itself needs root to nsenter into PID 1's mnt namespace
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# anyway, so bypassing sandbox here is no looser than the sudoers rule
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# the web app uses for its own helper invocations.
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ExecStartPre=+/usr/local/libexec/left4me/left4me-overlay mount %i
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ExecStart=/var/lib/left4me/installation/srcds_run -game left4dead2 +hostport ${L4D2_PORT} $L4D2_ARGS
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Restart=on-failure
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RestartSec=5
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# Bound the restart loop. Without these, a persistent ExecStartPre or
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# ExecStart failure spins indefinitely (default systemd has no cap when
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# Restart= is explicitly set without StartLimit*).
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StartLimitBurst=5
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StartLimitIntervalSec=60s
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# Resource control baseline — see docs/superpowers/specs/2026-05-09-l4d2-server-host-perf-baseline-design.md
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Slice=l4d2-game.slice
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Nice=-5
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IOSchedulingClass=best-effort
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IOSchedulingPriority=4
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OOMScoreAdjust=-200
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MemoryHigh=1.5G
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MemoryMax=2G
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TasksMax=256
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LimitNOFILE=65536
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KillSignal=SIGINT
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TimeoutStopSec=15s
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LogRateLimitIntervalSec=0
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# Hardening (unchanged from previous baseline).
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NoNewPrivileges=true
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PrivateTmp=true
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PrivateDevices=true
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ProtectHome=true
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ProtectSystem=strict
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ReadOnlyPaths=/var/lib/left4me/installation /var/lib/left4me/overlays
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ReadWritePaths=/var/lib/left4me/runtime/%i
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RestrictSUIDSGID=true
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LockPersonality=true
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[Install]
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WantedBy=multi-user.target
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