A secret mv between vaults unlocks both vaults before taking the lock (closes #189)

A move between two vaults unlocked them while holding the state directory
lock, and unlocking can ask for a passphrase, so every other changing
command waited at that prompt. moveSecretCrossVault now checks the move,
unlocks both vaults, and only then takes the lock. Under the lock,
copySecretAndRemoveSource checks again that the source and the destination
vault still exist, then copies. A move within a vault takes the lock in
moveSecretWithinVault, so MoveSecret takes none itself.

The two tests of a source that cannot be removed now call
copySecretAndRemoveSource, since the lock refuses their wrapped
filesystems.

Model: opus-5-5

internal/cli/move_cross_vault_test.go

@@ -4,12 +4,15 @@ package cli
 import (
 	"errors"
 	"path/filepath"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/secret"
 	"sneak.berlin/go/secret/internal/vault"
 )
 
@@ -92,7 +95,8 @@ func requireValue(t *testing.T, fs afero.Fs, vaultName, secretName string) {
 // vaults whose source could not be removed reported the secret moved and
 // succeeded. It must fail, and the copy and the source must both be there.
 // The state directory lock refuses the wrapped filesystem, so the test
-// calls moveSecret, which MoveSecret runs once it holds the lock.
+// calls copySecretAndRemoveSource, which a move between vaults runs once it
+// holds the lock.
 func TestCrossVaultMoveFailsWhenSourceRemains(t *testing.T) {
 	t.Parallel()
 
@@ -103,9 +107,12 @@ func TestCrossVaultMoveFailsWhenSourceRemains(t *testing.T) {
 		Fs:   base,
 		path: testStateDir + "/vaults.d/default/secrets.d/x",
 	}, testStateDir)
-	instance.Mnemonic = testMnemonicBuffer(t)
 
-	err := instance.moveSecret(&cobra.Command{}, "default:x", "work:y", false)
+	source := vault.NewVault(instance.fs, testStateDir, "default")
+	source.Mnemonic = testMnemonicBuffer(t)
+
+	err := instance.copySecretAndRemoveSource(&cobra.Command{}, source, "x",
+		vault.NewVault(instance.fs, testStateDir, "work"), "y", false)
 	require.ErrorIs(t, err, errPermissionDenied)
 	require.ErrorContains(t, err, "secret 'default:x' is copied with all "+
 		"1 version(s) to 'work:y', but the source remains")
@@ -128,9 +135,12 @@ func TestCrossVaultMoveFailsWhenOldFilesRemain(t *testing.T) {
 	fs := &removeAllFailFs{Fs: base, dir: sourceVaultDir}
 
 	instance := NewCLIInstanceWithStateDir(fs, testStateDir)
-	instance.Mnemonic = testMnemonicBuffer(t)
 
-	err := instance.moveSecret(&cobra.Command{}, "default:x", "work:y", false)
+	source := vault.NewVault(fs, testStateDir, "default")
+	source.Mnemonic = testMnemonicBuffer(t)
+
+	err := instance.copySecretAndRemoveSource(&cobra.Command{}, source, "x",
+		vault.NewVault(fs, testStateDir, "work"), "y", false)
 	require.ErrorIs(t, err, errPermissionDenied)
 	require.ErrorContains(t, err, "secret 'default:x' is moved with all "+
 		"1 version(s) to 'work:y', but its old files could not all be deleted")
@@ -150,3 +160,138 @@ func TestCrossVaultMoveFailsWhenOldFilesRemain(t *testing.T) {
 
 	requireValue(t, base, "work", "y")
 }
+
+// TestCrossVaultMoveUnlocksBeforeLocking is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/189: a move between two vaults
+// unlocked them while holding the state directory lock, and unlocking a
+// vault can ask for its passphrase, so every other command that changes
+// anything waited while the user answered. Here each vault has a passphrase
+// unlocker whose passphrase is the vault's name, and the move is given the
+// passphrase of only one of them. Run while the test holds the lock, it
+// must fail to unlock the other vault without waiting for the lock.
+//
+//nolint:paralleltest // times commands against the in-memory lock all tests share
+func TestCrossVaultMoveUnlocksBeforeLocking(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	createCrossVaults(t, fs)
+
+	vaults, err := vault.ListVaults(fs, testStateDir)
+	require.NoError(t, err)
+
+	for _, name := range vaults {
+		vlt := vault.NewVault(fs, testStateDir, name)
+		vlt.Mnemonic = testMnemonicBuffer(t)
+
+		passphrase := memguard.NewBufferFromBytes([]byte(name))
+		_, err = vlt.CreatePassphraseUnlocker(passphrase)
+		passphrase.Destroy()
+		require.NoError(t, err)
+	}
+
+	// The move is from "default" to "work"
+	for _, tc := range []struct {
+		// failing is the vault that the move cannot unlock, given the
+		// passphrase of the vault named given
+		failing, given string
+	}{
+		{"source", "work"},
+		{"destination", "default"},
+	} {
+		t.Run(tc.failing, func(t *testing.T) {
+			passphrase := memguard.NewBufferFromBytes([]byte(tc.given))
+			defer passphrase.Destroy()
+
+			instance := NewCLIInstanceWithStateDir(fs, testStateDir)
+			instance.UnlockPassphrase = passphrase
+
+			release, err := vault.LockStateDir(fs, testStateDir)
+			require.NoError(t, err)
+			// Also frees a waiting move if the test fails, so that it
+			// releases the lock the other tests use
+			defer release()
+
+			done := make(chan error, 1)
+
+			go func() {
+				done <- instance.MoveSecret(&cobra.Command{},
+					"default:x", "work:y", false)
+			}()
+
+			select {
+			case err := <-done:
+				require.ErrorIs(t, err, secret.ErrWrongPassphrase)
+				require.ErrorContains(t, err,
+					"failed to unlock "+tc.failing+" vault")
+			case <-time.After(lockWait):
+				t.Fatal("waited for the lock before unlocking the " +
+					tc.failing + " vault")
+			}
+		})
+	}
+}
+
+// TestCrossVaultMoveChecksAgainOnceLocked starts a move between two vaults,
+// given the mnemonic, while the test holds the state directory lock. Once
+// the move waits for the lock, the test removes what another command could
+// have removed in the meantime, then releases the lock. The move must fail
+// with the error that says what is missing.
+//
+//nolint:paralleltest // waitingForLock sees any test's command waiting for the lock
+func TestCrossVaultMoveChecksAgainOnceLocked(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		// removed is the directory, under the state directory, that the
+		// test removes
+		removed string
+		want    error
+	}{
+		{"source", "/vaults.d/default/secrets.d/x", vault.ErrSecretNotFound},
+		{"destination vault", "/vaults.d/work", vault.ErrVaultNotFound},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			fs := afero.NewMemMapFs()
+			createCrossVaults(t, fs)
+
+			release, err := vault.LockStateDir(fs, testStateDir)
+			require.NoError(t, err)
+
+			// Released at most once, and also if the test fails while
+			// holding it, so that later tests can take it
+			release = sync.OnceFunc(release)
+			defer release()
+
+			instance := NewCLIInstanceWithStateDir(fs, testStateDir)
+			instance.Mnemonic = testMnemonicBuffer(t)
+
+			done := make(chan error, 1)
+
+			go func() {
+				done <- instance.MoveSecret(&cobra.Command{},
+					"default:x", "work:y", false)
+			}()
+
+			timeout := time.After(lockWait)
+
+			for !waitingForLock() {
+				select {
+				case err := <-done:
+					t.Fatalf("finished while the lock was held, with error %v",
+						err)
+				case <-timeout:
+					t.Fatal("never waited for the lock")
+				case <-time.After(time.Millisecond):
+				}
+			}
+
+			require.NoError(t, fs.RemoveAll(testStateDir+tc.removed))
+			release()
+
+			select {
+			case err := <-done:
+				require.ErrorIs(t, err, tc.want)
+			case <-time.After(lockWait):
+				t.Fatal("did not finish once the lock was released")
+			}
+		})
+	}
+}