fix(cli): journal that allowed destinations fail closed on a maintenance start

A maintenance fallback start holds no resolver config, and Allowed
Destinations (a master-only Firewall Mode feature) are not persisted with
the configuration on disk. Under Firewall Mode the exception set is
therefore empty until the API answers, so raw-IP destinations the
organization allowed stay blocked for the window, and a persisted pf
table from the previous run is replaced by the empty set.

Keep that fail-closed on purpose: the list is the organization's network
topology and is kept out of persisted state. Journal a Warn when a
fallback start applies the empty set under Firewall Mode so the blocked
destinations are explained, and pin that the first answer after recovery
re-applies the list.

Also capitalize the two managed-config marker log messages to match the
rest of master.

cmd/cli/api_maintenance.go

@@ -224,7 +224,7 @@ func persistManagedConfig(cfg *ctrld.Config, logger *ctrld.Logger) {
 		return
 	}
 	if err := recordManagedConfig(cdUID); err != nil {
-		logger.Warn().Err(err).Msg("could not record that this configuration came from the API")
+		logger.Warn().Err(err).Msg("Could not record that this configuration came from the API")
 	}
 }
 
@@ -246,6 +246,6 @@ func recordManagedConfigForStart(fetchedThisRun, wasManagedBeforeWrite bool) {
 	if err := recordManagedConfig(cdUID); err != nil {
 		// Not fatal: this run is fine. It only costs the next start its
 		// fallback if the API is in maintenance then.
-		mainLog.Load().Warn().Err(err).Msg("could not record that this configuration came from the API")
+		mainLog.Load().Warn().Err(err).Msg("Could not record that this configuration came from the API")
 	}
 }

cmd/cli/api_maintenance_firewall_test.go

@@ -0,0 +1,96 @@
+package cli
+
+import (
+	"context"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/Control-D-Inc/ctrld"
+	"github.com/Control-D-Inc/ctrld/internal/controld"
+)
+
+// TestMaintenanceFallbackFirewallAllowedDestinations covers Firewall Mode on a
+// maintenance fallback start. The organization's Allowed Destinations exist
+// only in the API answer, which such a run does not have, so the exception set
+// is empty until the API returns. That is a deliberate fail-closed state: it
+// must be named in the retained journal, and the first answer after recovery
+// must re-apply the list even though nothing else is compared as changed.
+func TestMaintenanceFallbackFirewallAllowedDestinations(t *testing.T) {
+	allowed := netip.MustParseAddr("203.0.113.10")
+
+	t.Run("fallback start journals that allowed destinations are not enforced", func(t *testing.T) {
+		logs := captureDebugMainLog(t)
+		p := progWithAllowList()
+		p.logger.Store(mainLog.Load())
+		p.startedInAPIMaintenance.Store(true)
+
+		p.syncAllowedDestinations()
+
+		events := jsonLogEvents(t, logs, "Firewall: organization allowed destinations are not enforced until the Control D API answers; started on the configuration on disk during maintenance")
+		if len(events) != 1 {
+			t.Fatalf("fail-closed warnings: got %d, want 1", len(events))
+		}
+		if events[0]["level"] != "warn" {
+			t.Errorf("level = %v, want warn", events[0]["level"])
+		}
+		if events[0]["reason"] != "api_maintenance" {
+			t.Errorf("reason = %v, want api_maintenance", events[0]["reason"])
+		}
+		if events[0]["journal"] != true {
+			t.Error("the fail-closed warning is not retained in the journal")
+		}
+		if p.allowList.Contains(allowed) {
+			t.Fatalf("%s allowed with no resolver config", allowed)
+		}
+	})
+
+	t.Run("a normal start with no resolver config stays quiet", func(t *testing.T) {
+		logs := captureDebugMainLog(t)
+		p := progWithAllowList()
+		p.logger.Store(mainLog.Load())
+
+		p.syncAllowedDestinations()
+
+		if got := len(jsonLogEvents(t, logs, "Firewall: organization allowed destinations are not enforced until the Control D API answers; started on the configuration on disk during maintenance")); got != 0 {
+			t.Fatalf("fail-closed warnings outside maintenance: got %d, want 0", got)
+		}
+	})
+
+	t.Run("firewall mode off stays quiet", func(t *testing.T) {
+		logs := captureDebugMainLog(t)
+		p := &prog{}
+		p.logger.Store(mainLog.Load())
+		p.startedInAPIMaintenance.Store(true)
+
+		p.syncAllowedDestinations()
+
+		if got := len(jsonLogEvents(t, logs, "Firewall: organization allowed destinations are not enforced until the Control D API answers; started on the configuration on disk during maintenance")); got != 0 {
+			t.Fatalf("fail-closed warnings with Firewall Mode off: got %d, want 0", got)
+		}
+	})
+
+	t.Run("pending recovery re-applies the list", func(t *testing.T) {
+		p := progWithAllowList()
+		p.apiReloadCh = make(chan *ctrld.Config, 1)
+		p.startedInAPIMaintenance.Store(true)
+		// The fallback start applied an empty set.
+		p.syncAllowedDestinations()
+		if p.allowList.Contains(allowed) {
+			t.Fatalf("%s allowed before recovery", allowed)
+		}
+
+		p.applyFetchedResolverConfig(context.Background(), discardLogger(), &controld.ResolverConfig{
+			DestinationIPs: []string{"203.0.113.10"},
+		}, false, time.Now().Unix())
+
+		if !p.allowList.Contains(allowed) {
+			t.Fatalf("recovery did not re-apply the organization list: %s blocked", allowed)
+		}
+		select {
+		case <-p.apiReloadCh:
+		default:
+			t.Fatal("pending recovery did not deliver the answer to the apply path")
+		}
+	})
+}

cmd/cli/firewall.go

@@ -218,6 +218,17 @@ func (p *prog) syncAllowedDestinations() {
 	var entries []string
 	if rc != nil {
 		entries = rc.DestinationIPs
+	} else if al != nil && p.startedInAPIMaintenance.Load() {
+		// A maintenance fallback start holds no resolver config, and the
+		// organization's list is not persisted with the configuration on disk,
+		// so the exception set below is empty: raw-IP destinations the
+		// organization allowed stay blocked until the API answers and the
+		// recovery refresh re-applies the list. Failing closed is deliberate -
+		// the list is the organization's network topology, which is kept out of
+		// persisted state - so say so in the retained journal rather than leave
+		// the blocked destinations unexplained.
+		journal(p.Warn()).Str("reason", "api_maintenance").
+			Msg("Firewall: organization allowed destinations are not enforced until the Control D API answers; started on the configuration on disk during maintenance")
 	}
 	p.applyAllowedDestinations(al, entries)
 }