A pair credential is sealed to the operator key too

The secret the vault provides a module is the credential of the consumer↔vault
pair, and so is every credential a provider grants; sealing only own secrets
to the operator left exactly those unrecoverable. Same column, same call; the
export and `secret recover` address a pair by consumer node, module and the
provision's name, and say which kind each entry is.

internal/inventory/migrations/0024-a-pair-credential-is-sealed-to-the-operator-too.sql

@@ -0,0 +1,10 @@
+-- The same second seal for a pair credential (novox/hq ADR 0085, amended).
+--
+-- 0023 gave a module's own secrets an operator-sealed copy. A secret the vault provides to a module
+-- is not an own secret -- it is the credential of the consumer-vault pair -- and so were the
+-- credentials every provider grants. Without this, a vault-provided password could be rotated and
+-- audited but not recovered, which is a vault that keeps everything except what it was for.
+
+alter table secret
+    add column operator_sealed text,
+    add column operator_key    text;

internal/inventory/operator.go

@@ -69,17 +69,21 @@ type Kept = catalogue.Kept
 // an export say what it does not cover, rather than being taken for complete.
 func (i *Inventory) KeptForOperator(ctx context.Context) (kept []Kept, unrecoverable []Kept, err error) {
 	rows, err := i.store.Pool().Query(ctx,
-		`select n.name, s.module, s.name, s.origin, coalesce(s.operator_sealed, ''),
+		`select 'own', n.name, s.module, s.name, '', s.origin, coalesce(s.operator_sealed, ''),
 		        coalesce(s.operator_key, ''), s.made_at
 		   from module_secret s join node n on n.id = s.node
-		  order by n.name, s.module, s.name`)
+		 union all
+		 select 'pair', c.name, s.consumer_module, s.name, p.name, 'made', coalesce(s.operator_sealed, ''),
+		        coalesce(s.operator_key, ''), s.created_at
+		   from secret s join node c on c.id = s.consumer join node p on p.id = s.provider
+		  order by 1, 2, 3, 4`)
 	if err != nil {
 		return nil, nil, err
 	}
 	defer rows.Close()
 	for rows.Next() {
 		var k Kept
-		if err := rows.Scan(&k.Node, &k.Module, &k.Name, &k.Origin, &k.Sealed, &k.Key, &k.MadeAt); err != nil {
+		if err := rows.Scan(&k.Kind, &k.Node, &k.Module, &k.Name, &k.Provider, &k.Origin, &k.Sealed, &k.Key, &k.MadeAt); err != nil {
 			return nil, nil, err
 		}
 		if k.Sealed == "" {
@@ -93,15 +97,25 @@ func (i *Inventory) KeptForOperator(ctx context.Context) (kept []Kept, unrecover
 
 // KeptSecret is one secret's operator-sealed copy, for recovery.
 func (i *Inventory) KeptSecret(ctx context.Context, node, module, name string) (Kept, error) {
+	// An own secret first, then a pair credential by the provision's name. A module whose own
+	// secret and requirement share a name is refused at resolution, so the two cannot both answer.
 	var k Kept
 	err := i.store.Pool().QueryRow(ctx,
-		`select n.name, s.module, s.name, s.origin, coalesce(s.operator_sealed, ''),
+		`select 'own', n.name, s.module, s.name, '', s.origin, coalesce(s.operator_sealed, ''),
 		        coalesce(s.operator_key, ''), s.made_at
 		   from module_secret s join node n on n.id = s.node
 		  where n.name = $1 and s.module = $2 and s.name = $3`, node, module, name).
-		Scan(&k.Node, &k.Module, &k.Name, &k.Origin, &k.Sealed, &k.Key, &k.MadeAt)
+		Scan(&k.Kind, &k.Node, &k.Module, &k.Name, &k.Provider, &k.Origin, &k.Sealed, &k.Key, &k.MadeAt)
 	if errors.Is(err, pgx.ErrNoRows) {
-		return Kept{}, fmt.Errorf("%s on %s holds nothing called %q", module, node, name)
+		err = i.store.Pool().QueryRow(ctx,
+			`select 'pair', c.name, s.consumer_module, s.name, p.name, 'made', coalesce(s.operator_sealed, ''),
+			        coalesce(s.operator_key, ''), s.created_at
+			   from secret s join node c on c.id = s.consumer join node p on p.id = s.provider
+			  where c.name = $1 and s.consumer_module = $2 and s.name = $3`, node, module, name).
+			Scan(&k.Kind, &k.Node, &k.Module, &k.Name, &k.Provider, &k.Origin, &k.Sealed, &k.Key, &k.MadeAt)
+	}
+	if errors.Is(err, pgx.ErrNoRows) {
+		return Kept{}, fmt.Errorf("%s on %s holds nothing called %q — neither a secret of its own nor a credential for a provision", module, node, name)
 	}
 	if err != nil {
 		return Kept{}, err

internal/inventory/operator_test.go

@@ -1,6 +1,7 @@
 package inventory
 
 import (
+	"context"
 	"testing"
 
 	"github.com/novox/mesh-controller/internal/catalogue"
@@ -95,3 +96,74 @@ func TestAnOwnSecretIsSealedToTheOperatorToo(t *testing.T) {
 		t.Fatal("the new key is not the mesh's key")
 	}
 }
+
+// A pair credential — what the vault provides a module — is sealed to the operator too, and the
+// operator's copy is the very value the consumer's node unseals.
+func TestAPairCredentialIsSealedToTheOperatorToo(t *testing.T) {
+	inv := fresh(t)
+	ctx := context.Background()
+	// Two nodes with keys, keeping the consumer's opener: the test made the key, so it can play the
+	// consumer's host for one assertion.
+	var openAsConsumer func(string) ([]byte, bool)
+	for _, n := range []string{"consumer", "provider"} {
+		node, err := inv.AddNode(ctx, n)
+		if err != nil {
+			t.Fatal(err)
+		}
+		key, open := aSealingKey(t)
+		if n == "consumer" {
+			openAsConsumer = open
+		}
+		if err := inv.RecordSealingKey(ctx, node.ID, key); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, m := range []string{"gitea", "mesh-vault"} {
+		if err := inv.RegisterModule(ctx, catalogue.Manifest{Module: m, Version: "1"}, Source{}); err != nil {
+			t.Fatal(err)
+		}
+	}
+	pub, priv, err := secrets.Keypair()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := inv.SetOperatorKey(ctx, pub); err != nil {
+		t.Fatal(err)
+	}
+	made, err := inv.SecretFor(ctx, "secret", "consumer", "gitea", "provider")
+	if err != nil {
+		t.Fatal(err)
+	}
+	kept, err := inv.KeptSecret(ctx, "consumer", "gitea", "secret")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if kept.Kind != "pair" || kept.Provider != "provider" {
+		t.Fatalf("kept as %+v", kept)
+	}
+	fromOperator, err := secrets.Open(priv, kept.Sealed)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// The consumer's blob is sealed to the consumer node. Same value, two recipients.
+	fromNode, ok := openAsConsumer(made.ForConsumer)
+	if !ok {
+		t.Fatal("the consumer cannot open its own blob")
+	}
+	if string(fromOperator) != string(fromNode) {
+		t.Fatal("the operator's copy of the pair credential differs from the consumer's")
+	}
+	all, _, err := inv.KeptForOperator(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var pairs int
+	for _, k := range all {
+		if k.Kind == "pair" {
+			pairs++
+		}
+	}
+	if pairs != 1 {
+		t.Fatalf("%d pair credential(s) in the export, expected 1", pairs)
+	}
+}

internal/inventory/secrets.go

@@ -74,20 +74,35 @@ func (i *Inventory) SecretFor(ctx context.Context, name, consumer, consumerModul
 		return held, nil
 	}
 
-	made, err := secrets.Make(consumerKey, providerKey)
+	// And to the operator, when the mesh has one (novox/hq ADR 0085, amended): the third copy that
+	// makes a vault-provided secret recoverable, and nothing the mesh can open.
+	operator, err := i.OperatorKey(ctx)
 	if err != nil {
 		return Secret{}, err
 	}
+	var also []string
+	if operator != "" {
+		also = append(also, operator)
+	}
+	made, more, err := secrets.MakeAlso(consumerKey, providerKey, also...)
+	if err != nil {
+		return Secret{}, err
+	}
+	var forOperator, operatorKey *string
+	if operator != "" {
+		forOperator, operatorKey = &more[0], &operator
+	}
 	_, err = i.store.Pool().Exec(ctx,
 		`insert into secret (name, consumer, consumer_module, provider, for_consumer, for_provider,
-		                     consumer_key, provider_key)
-		 values ($1, $2, $3, $4, $5, $6, $7, $8)
+		                     consumer_key, provider_key, operator_sealed, operator_key)
+		 values ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
 		 on conflict (name, consumer, consumer_module, provider) do update set
 		   for_consumer = excluded.for_consumer, for_provider = excluded.for_provider,
 		   consumer_key = excluded.consumer_key, provider_key = excluded.provider_key,
-		   created_at = now()`,
+		   created_at = now(),
+		   operator_sealed = excluded.operator_sealed, operator_key = excluded.operator_key`,
 		name, consumerNode.ID, consumerModule, providerNode.ID,
-		made.ForConsumer, made.ForProvider, made.ConsumerKey, made.ProviderKey)
+		made.ForConsumer, made.ForProvider, made.ConsumerKey, made.ProviderKey, forOperator, operatorKey)
 	if err != nil {
 		return Secret{}, err
 	}