backport of commit 3d37a2507bc1e54e2dc5e95c7cd099790543b3d1 (#23810)

Co-authored-by: Peter Wilson <peter.wilson@hashicorp.com>

vault/barrier_aes_gcm.go

@@ -211,6 +211,11 @@ func (b *AESGCMBarrier) Initialize(ctx context.Context, key, sealKey []byte, rea
 // persistKeyring is used to write out the keyring using the
 // root key to encrypt it.
 func (b *AESGCMBarrier) persistKeyring(ctx context.Context, keyring *Keyring) error {
+	const (
+		// The keyring is persisted before the root key.
+		keyringTimeout = 1 * time.Second
+	)
+
 	// Create the keyring entry
 	keyringBuf, err := keyring.Serialize()
 	defer memzero(keyringBuf)
@@ -221,13 +226,13 @@ func (b *AESGCMBarrier) persistKeyring(ctx context.Context, keyring *Keyring) er
 	// Create the AES-GCM
 	gcm, err := b.aeadFromKey(keyring.RootKey())
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to retrieve AES-GCM AEAD from root key: %w", err)
 	}
 
 	// Encrypt the barrier init value
 	value, err := b.encrypt(keyringPath, initialKeyTerm, gcm, keyringBuf)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to encrypt barrier initial value: %w", err)
 	}
 
 	// Create the keyring physical entry
@@ -235,7 +240,12 @@ func (b *AESGCMBarrier) persistKeyring(ctx context.Context, keyring *Keyring) er
 		Key:   keyringPath,
 		Value: value,
 	}
-	if err := b.backend.Put(ctx, pe); err != nil {
+
+	// We reduce the timeout on the initial 'put' but if this succeeds we will
+	// allow longer later on when we try to persist the root key .
+	ctxKeyring, cancelKeyring := context.WithTimeout(ctx, keyringTimeout)
+	defer cancelKeyring()
+	if err := b.backend.Put(ctxKeyring, pe); err != nil {
 		return fmt.Errorf("failed to persist keyring: %w", err)
 	}
 
@@ -255,11 +265,11 @@ func (b *AESGCMBarrier) persistKeyring(ctx context.Context, keyring *Keyring) er
 	activeKey := keyring.ActiveKey()
 	aead, err := b.aeadFromKey(activeKey.Value)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to retrieve AES-GCM AEAD from active key: %w", err)
 	}
 	value, err = b.encryptTracked(rootKeyPath, activeKey.Term, aead, keyBuf)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to encrypt and track active key value: %w", err)
 	}
 
 	// Update the rootKeyPath for standby instances
@@ -267,6 +277,9 @@ func (b *AESGCMBarrier) persistKeyring(ctx context.Context, keyring *Keyring) er
 		Key:   rootKeyPath,
 		Value: value,
 	}
+
+	// Use the longer timeout from the original context, for the follow-up write
+	// to persist the root key, as the initial storage of the keyring was successful.
 	if err := b.backend.Put(ctx, pe); err != nil {
 		return fmt.Errorf("failed to persist root key: %w", err)
 	}

vault/barrier_aes_gcm_test.go

@@ -12,10 +12,12 @@ import (
 	"time"
 
 	log "github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/vault/helper/testhelpers/corehelpers"
 	"github.com/hashicorp/vault/sdk/helper/logging"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/sdk/physical"
 	"github.com/hashicorp/vault/sdk/physical/inmem"
+	"github.com/stretchr/testify/require"
 )
 
 var logger = logging.NewVaultLogger(log.Trace)
@@ -694,3 +696,79 @@ func TestBarrier_LegacyRotate(t *testing.T) {
 		t.Fail()
 	}
 }
+
+// TestBarrier_persistKeyring_Context checks that we get the right errors if
+// the context is cancelled or times-out before the first part of persistKeyring
+// is able to persist the keyring itself (i.e. we don't go on to try and persist
+// the root key).
+func TestBarrier_persistKeyring_Context(t *testing.T) {
+	t.Parallel()
+
+	tests := map[string]struct {
+		shouldCancel         bool
+		isErrorExpected      bool
+		expectedErrorMessage string
+		contextTimeout       time.Duration
+		testTimeout          time.Duration
+	}{
+		"cancelled": {
+			shouldCancel:         true,
+			isErrorExpected:      true,
+			expectedErrorMessage: "failed to persist keyring: context canceled",
+			contextTimeout:       8 * time.Second,
+			testTimeout:          10 * time.Second,
+		},
+		"timeout-before-keyring": {
+			isErrorExpected:      true,
+			expectedErrorMessage: "failed to persist keyring: context deadline exceeded",
+			contextTimeout:       1 * time.Nanosecond,
+			testTimeout:          5 * time.Second,
+		},
+	}
+
+	for name, tc := range tests {
+		name := name
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			// Set up barrier
+			backend, err := inmem.NewInmem(nil, corehelpers.NewTestLogger(t))
+			require.NoError(t, err)
+			barrier, err := NewAESGCMBarrier(backend)
+			require.NoError(t, err)
+			key, err := barrier.GenerateKey(rand.Reader)
+			require.NoError(t, err)
+			err = barrier.Initialize(context.Background(), key, nil, rand.Reader)
+			require.NoError(t, err)
+			err = barrier.Unseal(context.Background(), key)
+			require.NoError(t, err)
+			k := barrier.keyring.TermKey(1)
+			k.Encryptions = 0
+			k.InstallTime = time.Now().Add(-24 * 366 * time.Hour)
+
+			// Persist the keyring
+			ctx, cancel := context.WithTimeout(context.Background(), tc.contextTimeout)
+			persistChan := make(chan error)
+			go func() {
+				if tc.shouldCancel {
+					cancel()
+				}
+				persistChan <- barrier.persistKeyring(ctx, barrier.keyring)
+			}()
+
+			select {
+			case err := <-persistChan:
+				switch {
+				case tc.isErrorExpected:
+					require.Error(t, err)
+					require.EqualError(t, err, tc.expectedErrorMessage)
+				default:
+					require.NoError(t, err)
+				}
+			case <-time.After(tc.testTimeout):
+				t.Fatal("timeout reached")
+			}
+		})
+	}
+}