Read secret environment variables once per command, then unset them (closes #60)

init and vault create put the mnemonic into the process environment for
vault.CreateVault to read back, so every program they ran, gpg included,
inherited it, and SB_SECRET_MNEMONIC and SB_UNLOCK_PASSPHRASE were read
at 13 places and never unset. Each command that may need them now reads
both once, in its RunE, into locked buffers on the CLI Instance, and
unsets them at once. The buffers are passed down: vault.CreateVault
takes the mnemonic, a Vault carries Mnemonic and UnlockPassphrase, and
the PGP, keychain and Secure Enclave unlocker constructors take both;
CreatePGPUnlocker sets them on the vault it loads through SetMnemonic
and SetUnlockPassphrase, new in VaultInterface. README warns against
both variables.

Model: opus-5-5

internal/cli/cli.go

@@ -3,8 +3,10 @@ package cli
 
 import (
 	"fmt"
+	"os"
 
 	"git.eeqj.de/sneak/secret/internal/secret"
+	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 )
@@ -14,6 +16,11 @@ type Instance struct {
 	fs       afero.Fs
 	stateDir string
 	cmd      *cobra.Command
+	// Mnemonic and UnlockPassphrase hold the values of SB_SECRET_MNEMONIC
+	// and SB_UNLOCK_PASSPHRASE that readSecretEnv read, or nil when it found
+	// none.
+	Mnemonic         *memguard.LockedBuffer
+	UnlockPassphrase *memguard.LockedBuffer
 }
 
 // NewCLIInstance creates a new CLI instance with the real filesystem
@@ -68,3 +75,43 @@ func (cli *Instance) SetStateDir(stateDir string) {
 func (cli *Instance) GetStateDir() string {
 	return cli.stateDir
 }
+
+// readSecretEnv reads SB_SECRET_MNEMONIC into cli.Mnemonic and
+// SB_UNLOCK_PASSPHRASE into cli.UnlockPassphrase. A command that may need
+// either calls it once, before anything else, and passes the buffers on
+// from there: each variable is unset as soon as it is read, so that the
+// processes this one starts, gpg among them, do not inherit it, and a
+// second read would find nothing. The returned function destroys both
+// buffers.
+func (cli *Instance) readSecretEnv() func() {
+	cli.Mnemonic = readAndUnsetEnv(secret.EnvMnemonic)
+	cli.UnlockPassphrase = readAndUnsetEnv(secret.EnvUnlockPassphrase)
+
+	mnemonic, passphrase := cli.Mnemonic, cli.UnlockPassphrase
+
+	return func() {
+		if mnemonic != nil {
+			mnemonic.Destroy()
+		}
+
+		if passphrase != nil {
+			passphrase.Destroy()
+		}
+	}
+}
+
+// readAndUnsetEnv returns the value of the environment variable name in a
+// locked buffer, or nil when it is unset or empty, and unsets the variable.
+// Unsetting does not erase the value: it stays in this process's memory,
+// and in /proc/<pid>/environ, which shows the environment the process
+// started with. The caller must destroy the returned buffer.
+func readAndUnsetEnv(name string) *memguard.LockedBuffer {
+	value := os.Getenv(name)
+	_ = os.Unsetenv(name)
+
+	if value == "" {
+		return nil
+	}
+
+	return memguard.NewBufferFromBytes([]byte(value))
+}

internal/cli/create_vault_test.go

@@ -2,6 +2,7 @@ package cli_test
 
 import (
 	"bytes"
+	"os"
 	"testing"
 
 	"git.eeqj.de/sneak/secret/internal/cli"
@@ -20,16 +21,27 @@ import (
 // decrypted any more. Each must refuse, change nothing, and leave every
 // vault's secret readable through its passphrase unlocker.
 //
-//nolint:paralleltest // t.Setenv forbids parallel subtests
+//nolint:paralleltest // the cases share cmd
 func TestCreateExistingVaultChangesNothing(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	mnemonic := testMnemonicBuffer(t)
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	t.Cleanup(passphrase.Destroy)
+
+	// newCLI returns an instance on fs given the mnemonic and the unlock
+	// passphrase, as from the environment
+	newCLI := func(fs afero.Fs) *cli.Instance {
+		c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
+		c.Mnemonic = mnemonic
+		c.UnlockPassphrase = passphrase
+
+		return c
+	}
 
 	// `secret init`, `secret vault create work`, `secret vault select
 	// default`, and the secret "x" in each vault. "work" is then not the
 	// current vault, which creating it again must not change.
 	fs := afero.NewMemMapFs()
-	c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
+	c := newCLI(fs)
 	cmd := &cobra.Command{}
 
 	require.NoError(t, c.Init(cmd))
@@ -74,7 +86,7 @@ func TestCreateExistingVaultChangesNothing(t *testing.T) {
 		t.Run(tt.command, func(t *testing.T) {
 			fs := newFsFromSnapshot(t, before)
 
-			err := tt.run(cli.NewCLIInstanceWithStateDir(fs, testStateDir))
+			err := tt.run(newCLI(fs))
 
 			require.EqualError(t, err, tt.want)
 			require.Equal(t, before, snapshotStateDir(t, fs))
@@ -85,10 +97,11 @@ func TestCreateExistingVaultChangesNothing(t *testing.T) {
 	// reading each vault's secret once from it shows that it still decrypts
 	// after each case. Without the mnemonic, reading a secret goes through
 	// the vault's passphrase unlocker, which is slow.
-	t.Setenv(secret.EnvMnemonic, "")
-
 	for _, name := range vaults {
-		value, err := vault.NewVault(fs, testStateDir, name).GetSecret("x")
+		vlt := vault.NewVault(fs, testStateDir, name)
+		vlt.UnlockPassphrase = passphrase
+
+		value, err := vlt.GetSecret("x")
 		require.NoError(t, err)
 
 		unchanged := bytes.Equal([]byte("value"), value.Bytes())
@@ -98,19 +111,43 @@ func TestCreateExistingVaultChangesNothing(t *testing.T) {
 	}
 }
 
+// TestVaultCreationLeavesNoSecretInEnvironment is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/60, where `secret init` and
+// `secret vault create` put the mnemonic into the process environment,
+// which every program they ran inherited, and SB_SECRET_MNEMONIC and
+// SB_UNLOCK_PASSPHRASE were never unset. Each command, given both, must
+// leave neither in the environment.
+func TestVaultCreationLeavesNoSecretInEnvironment(t *testing.T) {
+	t.Setenv(secret.EnvStateDir, t.TempDir())
+
+	run := func(args ...string) {
+		t.Setenv(secret.EnvMnemonic, testMnemonic)
+		t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+
+		// With no terminal to prompt on, this succeeds only if the command
+		// read both variables
+		_, err := cli.ExecuteCommandInProcess(args, "", nil)
+		require.NoError(t, err)
+
+		for _, name := range []string{secret.EnvMnemonic, secret.EnvUnlockPassphrase} {
+			_, set := os.LookupEnv(name)
+			require.False(t, set, "%s is set after %v", name, args)
+		}
+	}
+
+	run("init")
+	run("vault", "create", "work")
+}
+
 // TestStopAtPassphrasePromptLeavesNothing is a regression test for the
 // review of https://git.eeqj.de/sneak/secret/pulls/82: `secret init` or
 // `secret vault create` stopped at the passphrase prompt left a vault with
 // no unlocker, which neither command would then create again. Each must ask
 // for the passphrase before writing anything.
 //
-//nolint:paralleltest // t.Setenv forbids parallel subtests
+//nolint:paralleltest // the cases share cmd
 func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
-	// Without the passphrase in the environment, both commands prompt for
-	// it, which fails because the tests do not run in a terminal.
-	t.Setenv(secret.EnvUnlockPassphrase, "")
+	mnemonic := testMnemonicBuffer(t)
 
 	// An empty state directory for `secret init`, and one holding the vault
 	// "default" for `secret vault create work`.
@@ -118,7 +155,7 @@ func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
 	require.NoError(t, empty.MkdirAll(testStateDir, secret.DirPerms))
 
 	withDefault := afero.NewMemMapFs()
-	_, err := vault.CreateVault(withDefault, testStateDir, "default")
+	_, err := vault.CreateVault(withDefault, testStateDir, "default", mnemonic)
 	require.NoError(t, err)
 
 	cmd := &cobra.Command{}
@@ -144,7 +181,12 @@ func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
 		t.Run(tt.command, func(t *testing.T) {
 			before := snapshotStateDir(t, tt.fs)
 
-			err := tt.run(cli.NewCLIInstanceWithStateDir(tt.fs, testStateDir))
+			// Given no unlock passphrase, both commands prompt for it, which
+			// fails because the tests do not run in a terminal.
+			c := cli.NewCLIInstanceWithStateDir(tt.fs, testStateDir)
+			c.Mnemonic = mnemonic
+
+			err := tt.run(c)
 
 			require.ErrorContains(t, err, "failed to read passphrase")
 			require.Equal(t, before, snapshotStateDir(t, tt.fs))

internal/cli/crypto.go

@@ -41,6 +41,9 @@ func newCryptoCmd(
 
 			cli.cmd = cmd
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return run(cli, args[0], inputFile, outputFile)
 		},
 	}
@@ -156,6 +159,8 @@ func (cli *Instance) Encrypt(secretName, inputFile, outputFile string) error {
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Get or create the age secret key for this secret
 	keyBuffer, err := cli.resolveEncryptionKey(vlt, secretName)
 	if err != nil {
@@ -230,6 +235,8 @@ func (cli *Instance) Decrypt(secretName, inputFile, outputFile string) error {
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Check if secret exists
 	secretObj := secret.NewSecret(vlt, secretName)
 
@@ -308,13 +315,13 @@ func isValidAgeSecretKey(key string) bool {
 	return err == nil
 }
 
-// getSecretValue retrieves the value of a secret using the appropriate
-// unlocker
+// getSecretValue retrieves the value of a secret with the vault's mnemonic
+// when it has one, else with the current unlocker
 func (cli *Instance) getSecretValue(
 	vlt *vault.Vault, secretObj *secret.Secret,
 ) (*memguard.LockedBuffer, error) {
-	if os.Getenv(secret.EnvMnemonic) != "" {
-		return secretObj.GetValue(nil)
+	if vlt.Mnemonic != nil {
+		return secretObj.GetValue(nil, vlt.Mnemonic)
 	}
 
 	unlocker, err := vlt.GetCurrentUnlocker()
@@ -322,5 +329,5 @@ func (cli *Instance) getSecretValue(
 		return nil, fmt.Errorf("failed to get current unlocker: %w", err)
 	}
 
-	return secretObj.GetValue(unlocker)
+	return secretObj.GetValue(unlocker, nil)
 }

internal/cli/generate.go

@@ -76,6 +76,9 @@ func newGenerateSecretCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.GenerateSecret(cmd, args[0], length, secretType, force)
 		},
 	}
@@ -167,6 +170,8 @@ func (cli *Instance) GenerateSecret(
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Protect the generated secret immediately
 	secretBuffer := memguard.NewBufferFromBytes([]byte(secretValue))
 	defer secretBuffer.Destroy()

internal/cli/init.go

@@ -39,16 +39,20 @@ func RunInit(cmd *cobra.Command, _ []string) error {
 		log.Fatalf("failed to initialize CLI: %v", err)
 	}
 
+	destroySecrets := cli.readSecretEnv()
+	defer destroySecrets()
+
 	return cli.Init(cmd)
 }
 
-// promptMnemonic reads the mnemonic from the environment or interactively.
-// The returned cleanup function must be deferred by the caller.
-func promptMnemonic() (string, func(), error) {
-	if envMnemonic := os.Getenv(secret.EnvMnemonic); envMnemonic != "" {
+// promptMnemonic returns the mnemonic from the environment, cli.Mnemonic,
+// or reads it interactively. The returned cleanup function must be deferred
+// by the caller.
+func (cli *Instance) promptMnemonic() (*memguard.LockedBuffer, func(), error) {
+	if cli.Mnemonic != nil {
 		secret.Debug("Using mnemonic from environment variable")
 
-		return envMnemonic, func() {}, nil
+		return cli.Mnemonic, func() {}, nil
 	}
 
 	secret.Debug("Prompting user for mnemonic phrase")
@@ -58,23 +62,23 @@ func promptMnemonic() (string, func(), error) {
 	if err != nil {
 		secret.Debug("Failed to read mnemonic from stdin", "error", err)
 
-		return "", nil, fmt.Errorf("failed to read mnemonic: %w", err)
+		return nil, nil, fmt.Errorf("failed to read mnemonic: %w", err)
 	}
 
 	fmt.Fprintln(os.Stderr) // Add newline after hidden input
 
-	return mnemonicBuffer.String(), mnemonicBuffer.Destroy, nil
+	return mnemonicBuffer, mnemonicBuffer.Destroy, nil
 }
 
 // setupDefaultVault creates the default vault and derives its long-term
 // identity from the mnemonic
 func (cli *Instance) setupDefaultVault(
-	stateDir, mnemonicStr string,
+	stateDir string, mnemonic *memguard.LockedBuffer,
 ) (*vault.Vault, *age.X25519Identity, error) {
 	// Create the default vault - it will handle key derivation internally
 	secret.Debug("Creating default vault")
 
-	vlt, err := vault.CreateVault(cli.fs, cli.stateDir, "default")
+	vlt, err := vault.CreateVault(cli.fs, cli.stateDir, "default", mnemonic)
 	if err != nil {
 		secret.Debug("Failed to create default vault", "error", err)
 
@@ -92,7 +96,7 @@ func (cli *Instance) setupDefaultVault(
 	}
 
 	// Derive the long-term key using the same index that CreateVault used
-	ltIdentity, err := agehd.DeriveIdentity(mnemonicStr, metadata.DerivationIndex)
+	ltIdentity, err := agehd.DeriveIdentity(mnemonic.String(), metadata.DerivationIndex)
 	if err != nil {
 		secret.Debug("Failed to derive long-term key", "error", err)
 
@@ -136,12 +140,13 @@ func (cli *Instance) initialize(cmd *cobra.Command) error {
 	}
 
 	// Prompt for mnemonic
-	mnemonicStr, cleanupMnemonic, err := promptMnemonic()
+	mnemonic, cleanupMnemonic, err := cli.promptMnemonic()
 	if err != nil {
 		return err
 	}
 	defer cleanupMnemonic()
 
+	mnemonicStr := mnemonic.String()
 	if mnemonicStr == "" {
 		secret.Debug("Empty mnemonic provided")
 
@@ -162,18 +167,14 @@ func (cli *Instance) initialize(cmd *cobra.Command) error {
 
 	// Ask for the unlocker passphrase before creating the vault, so that
 	// stopping at the prompt leaves no vault without an unlocker behind
-	passphraseBuffer, err := resolvePassphrase()
+	passphraseBuffer, cleanupPassphrase, err := cli.resolvePassphrase()
 	if err != nil {
 		return err
 	}
-	defer passphraseBuffer.Destroy()
-
-	// Set mnemonic in environment for CreateVault to use
-	restoreMnemonicEnv := setMnemonicEnv(mnemonicStr)
-	defer restoreMnemonicEnv()
+	defer cleanupPassphrase()
 
 	// Create the default vault and derive its long-term key
-	vlt, ltIdentity, err := cli.setupDefaultVault(stateDir, mnemonicStr)
+	vlt, ltIdentity, err := cli.setupDefaultVault(stateDir, mnemonic)
 	if err != nil {
 		return err
 	}

internal/cli/integration_test.go

@@ -286,7 +286,7 @@ func TestSecretManagerIntegration(t *testing.T) {
 	// Test 25: Concurrent operations
 	// Purpose: Test multiple simultaneous operations
 	// Expected: Proper locking/synchronization, no corruption
-	test25ConcurrentOperations(t, testMnemonic, runSecret, runSecretWithEnv)
+	test25ConcurrentOperations(t, tempDir, secretPath, testMnemonic, runSecret)
 
 	// Test 26: Large secret values
 	// Purpose: Test with large secret values (e.g., certificates)
@@ -2009,28 +2009,35 @@ func test24EnvironmentVariables(t *testing.T, tempDir, secretPath, testMnemonic,
 	assert.Equal(t, "env-test-value", strings.TrimSpace(string(cmdOutput2)))
 }
 
-func test25ConcurrentOperations(t *testing.T, testMnemonic string, runSecret func(...string) (string, error), runSecretWithEnv func(map[string]string, ...string) (string, error)) {
+func test25ConcurrentOperations(t *testing.T, tempDir, secretPath, testMnemonic string, runSecret func(...string) (string, error)) {
 	t.Helper()
 
 	// Make sure we're in default vault
 	_, err := runSecret("vault", "select", "default")
 	require.NoError(t, err, "vault select should succeed")
 
-	// Run multiple concurrent reads
+	// Run multiple concurrent reads, as separate processes: within one
+	// process the first command to read the mnemonic would unset it for
+	// the others
 	const numReaders = 5
 
 	errCh := make(chan error, numReaders)
 
 	for i := range numReaders {
 		go func(id int) {
-			output, err := runSecretWithEnv(map[string]string{
-				secret.EnvMnemonic: testMnemonic,
-			}, "get", "database/password")
+			cmd := exec.CommandContext(t.Context(), secretPath, "get", "database/password")
+			cmd.Env = []string{
+				secret.EnvStateDir + "=" + tempDir,
+				secret.EnvMnemonic + "=" + testMnemonic,
+				"PATH=" + os.Getenv("PATH"),
+				"HOME=" + os.Getenv("HOME"),
+			}
+			output, err := cmd.Output()
 
 			switch {
 			case err != nil:
 				errCh <- fmt.Errorf("reader %d failed: %w", id, err)
-			case strings.TrimSpace(output) == "":
+			case strings.TrimSpace(string(output)) == "":
 				errCh <- fmt.Errorf("%w: reader %d", errEmptyValue, id)
 			default:
 				errCh <- nil

internal/cli/lock_test.go

@@ -52,15 +52,18 @@ func lockInBackground(t *testing.T, fs afero.Fs) <-chan func() {
 }
 
 // addAtOnce runs one add of the secret name per value, all at once, and
-// returns their errors.
+// returns their errors. Each add is given mnemonic, which a forced add
+// needs.
 func addAtOnce(
 	fs afero.Fs, stateDir, name string, force bool, values []string,
+	mnemonic *memguard.LockedBuffer,
 ) []error {
 	errs := make(chan error, len(values))
 
 	for _, value := range values {
 		go func() {
 			cli := NewCLIInstanceWithStateDir(fs, stateDir)
+			cli.Mnemonic = mnemonic
 			cli.cmd = &cobra.Command{}
 			cli.cmd.SetIn(strings.NewReader(value))
 
@@ -92,9 +95,9 @@ func numbered(prefix string, count int) []string {
 // forced adds read the same highest version number and overwrite each
 // other's version. With it they behave as if run one after another.
 //
-//nolint:paralleltest // t.Setenv forbids parallel subtests
+//nolint:paralleltest // times commands against the in-memory lock all tests share
 func TestConcurrentAddsKeepEveryVersion(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	mnemonic := testMnemonicBuffer(t)
 
 	const adds = 8
 
@@ -107,14 +110,14 @@ func TestConcurrentAddsKeepEveryVersion(t *testing.T) {
 		{"real", afero.NewOsFs(), t.TempDir()},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			_, err := vault.CreateVault(tc.fs, tc.stateDir, "default")
+			_, err := vault.CreateVault(tc.fs, tc.stateDir, "default", mnemonic)
 			require.NoError(t, err)
 
 			// One add creates the secret; the others find that it exists
 			created := 0
 
 			for _, err := range addAtOnce(tc.fs, tc.stateDir, "shared", false,
-				numbered("create", adds)) {
+				numbered("create", adds), mnemonic) {
 				if err == nil {
 					created++
 				} else {
@@ -126,13 +129,15 @@ func TestConcurrentAddsKeepEveryVersion(t *testing.T) {
 
 			// Every forced add stores a version of its own
 			for _, err := range addAtOnce(tc.fs, tc.stateDir, "shared", true,
-				numbered("force", adds)) {
+				numbered("force", adds), mnemonic) {
 				require.NoError(t, err)
 			}
 
 			vlt, err := vault.GetCurrentVault(tc.fs, tc.stateDir)
 			require.NoError(t, err)
 
+			vlt.Mnemonic = mnemonic
+
 			vaultDir, err := vlt.GetDirectory()
 			require.NoError(t, err)
 
@@ -176,11 +181,11 @@ func (r *readNotifier) Read(p []byte) (int, error) {
 // taken the state directory lock before reading, it would hold the lock
 // while waiting for encrypt's output, and encrypt would wait for the lock
 // to store its key: neither would finish.
+//
+//nolint:paralleltest // times commands against the in-memory lock all tests share
 func TestEncryptPipedIntoAdd(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
 	fs := afero.NewMemMapFs()
-	_, err := vault.CreateVault(fs, testStateDir, "default")
+	_, err := vault.CreateVault(fs, testStateDir, "default", testMnemonicBuffer(t))
 	require.NoError(t, err)
 	require.NoError(t, afero.WriteFile(fs, testInput, []byte("piped"), 0o600))
 
@@ -283,14 +288,16 @@ func setupEveryCommand(
 ) (string, string) {
 	t.Helper()
 
-	other, err := vault.CreateVault(fs, testStateDir, "other")
+	mnemonic := testMnemonicBuffer(t)
+
+	other, err := vault.CreateVault(fs, testStateDir, "other", mnemonic)
 	require.NoError(t, err)
 
 	otherDir, err := other.GetDirectory()
 	require.NoError(t, err)
 	require.NoError(t, fs.Remove(filepath.Join(otherDir, "pub.age")))
 
-	vlt, err := vault.CreateVault(fs, testStateDir, "work")
+	vlt, err := vault.CreateVault(fs, testStateDir, "work", mnemonic)
 	require.NoError(t, err)
 
 	addTestSecret(t, vlt, []byte("older"), false)
@@ -363,7 +370,12 @@ func requireWaitsForLock(
 	release = sync.OnceFunc(release)
 	defer release()
 
+	unlockPassphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	defer unlockPassphrase.Destroy()
+
 	cli := NewCLIInstanceWithStateDir(fs, testStateDir)
+	cli.Mnemonic = testMnemonicBuffer(t)
+	cli.UnlockPassphrase = unlockPassphrase
 	cli.cmd = &cobra.Command{}
 	cli.cmd.SetIn(strings.NewReader("value"))
 	cli.cmd.SetOut(io.Discard)
@@ -400,11 +412,8 @@ func requireWaitsForLock(
 // TestChangingCommandsWaitForLock checks that each command that changes the
 // state directory waits for its lock.
 //
-//nolint:paralleltest // t.Setenv forbids parallel subtests
+//nolint:paralleltest // waitingForLock sees any test's command waiting for the lock
 func TestChangingCommandsWaitForLock(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
-
 	for _, tc := range []struct {
 		name         string
 		withUnlocker bool
@@ -468,15 +477,18 @@ func TestChangingCommandsWaitForLock(t *testing.T) {
 // TestEncryptWithExistingKeyTakesNoLock checks that secret encrypt with a
 // key that already exists, which only reads the state directory, finishes
 // while another command holds the state directory lock.
+//
+//nolint:paralleltest // times commands against the in-memory lock all tests share
 func TestEncryptWithExistingKeyTakesNoLock(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	mnemonic := testMnemonicBuffer(t)
 
 	fs := afero.NewMemMapFs()
-	_, err := vault.CreateVault(fs, testStateDir, "default")
+	_, err := vault.CreateVault(fs, testStateDir, "default", mnemonic)
 	require.NoError(t, err)
 	require.NoError(t, afero.WriteFile(fs, testInput, []byte("input"), 0o600))
 
 	encrypt := NewCLIInstanceWithStateDir(fs, testStateDir)
+	encrypt.Mnemonic = mnemonic
 	encrypt.cmd = &cobra.Command{}
 	encrypt.cmd.SetOut(io.Discard)
 
@@ -505,11 +517,11 @@ func TestEncryptWithExistingKeyTakesNoLock(t *testing.T) {
 // state directory lock by the time it writes its output. Holding it while
 // streaming would stall every other changing command for as long as the
 // stream lasts, and forever when the other end of the pipe is one of them.
+//
+//nolint:paralleltest // times commands against the in-memory lock all tests share
 func TestEncryptStreamsUnlocked(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
 	fs := afero.NewMemMapFs()
-	_, err := vault.CreateVault(fs, testStateDir, "default")
+	_, err := vault.CreateVault(fs, testStateDir, "default", testMnemonicBuffer(t))
 	require.NoError(t, err)
 	require.NoError(t, afero.WriteFile(fs, testInput, []byte("streamed"), 0o600))
 

internal/cli/move_test.go

@@ -6,7 +6,6 @@ import (
 	"testing"
 
 	"git.eeqj.de/sneak/secret/internal/cli"
-	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
@@ -20,9 +19,9 @@ import (
 // move within "work" left "work" the current vault. "default" is the current
 // vault in every case, and each case runs on its own copy of the state
 // directory.
-//
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
 func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
+	t.Parallel()
+
 	before := snapshotStateDir(t, newTwoVaultFs(t))
 	require.Equal(t, "default", before[testStateDir+"/currentvault"])
 
@@ -72,6 +71,8 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.command, func(t *testing.T) {
+			t.Parallel()
+
 			fs := newFsFromSnapshot(t, before)
 			c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
 
@@ -86,9 +87,9 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 // TestMoveWithinOtherVaultKeepsCurrentVault checks that `secret mv work:x
 // work:y`, with "default" the current vault, renames "x" to "y" in "work" and
 // leaves "default" the current vault.
-//
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
 func TestMoveWithinOtherVaultKeepsCurrentVault(t *testing.T) {
+	t.Parallel()
+
 	fs := newTwoVaultFs(t)
 	c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
 
@@ -111,10 +112,8 @@ func TestMoveWithinOtherVaultKeepsCurrentVault(t *testing.T) {
 // the secret "x", and the secrets.d of "other" is a link to that of
 // "default", so other:x is default:x. Each move must be rejected and leave
 // the secret and the links as they were.
-//
-//nolint:paralleltest // t.Setenv
 func TestMoveOntoSameSecretUnderAnotherNameIsRejected(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	const isSame = "is the same secret on this filesystem"
 
@@ -150,15 +149,17 @@ func TestMoveOntoSameSecretUnderAnotherNameIsRejected(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.command, func(t *testing.T) {
+			t.Parallel()
+
 			fs := afero.NewOsFs()
 			stateDir := t.TempDir()
 			vaultsDir := filepath.Join(stateDir, "vaults.d")
 
 			// "default" is created last, so it is the current vault.
-			_, err := vault.CreateVault(fs, stateDir, "other")
+			_, err := vault.CreateVault(fs, stateDir, "other", testMnemonicBuffer(t))
 			require.NoError(t, err)
 
-			vlt, err := vault.CreateVault(fs, stateDir, "default")
+			vlt, err := vault.CreateVault(fs, stateDir, "default", testMnemonicBuffer(t))
 			require.NoError(t, err)
 
 			err = vlt.AddSecret("x", memguard.NewBufferFromBytes([]byte("value")), false)
@@ -199,12 +200,12 @@ func TestMoveOntoSameSecretUnderAnotherNameIsRejected(t *testing.T) {
 // and "foo" are two secrets, `secret mv --force Foo foo` still replaces "foo"
 // with "Foo".
 func TestForcedCaseOnlyMoveOnCaseSensitiveFilesystem(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	fs := afero.NewOsFs()
 	stateDir := t.TempDir()
 
-	vlt, err := vault.CreateVault(fs, stateDir, "default")
+	vlt, err := vault.CreateVault(fs, stateDir, "default", testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	err = vlt.AddSecret("Foo", memguard.NewBufferFromBytes([]byte("upper")), false)

internal/cli/path_traversal_test.go

@@ -33,6 +33,17 @@ const (
 	missingFile = "/no/such/file"
 )
 
+// testMnemonicBuffer returns testMnemonic in a locked buffer that is
+// destroyed when the test ends.
+func testMnemonicBuffer(t *testing.T) *memguard.LockedBuffer {
+	t.Helper()
+
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	t.Cleanup(mnemonic.Destroy)
+
+	return mnemonic
+}
+
 // The state directory newTwoVaultFs copies, recorded by snapshotStateDir.
 // Creating a passphrase unlocker is slow by design, so the vaults are made
 // once, by the first test that needs them.
@@ -52,13 +63,12 @@ var (
 func newTwoVaultFs(t *testing.T) afero.Fs {
 	t.Helper()
 
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
 	twoVaultsOnce.Do(func() {
 		fs := afero.NewMemMapFs()
+		mnemonic := testMnemonicBuffer(t)
 
 		for _, name := range []string{"work", "default"} {
-			vlt, err := vault.CreateVault(fs, testStateDir, name)
+			vlt, err := vault.CreateVault(fs, testStateDir, name, mnemonic)
 			require.NoError(t, err)
 
 			err = vlt.AddSecret("x", memguard.NewBufferFromBytes([]byte("value")), false)
@@ -163,7 +173,7 @@ func requireRejectedAndUnchanged(
 // Moves and imports use --force, so that only the name check stands in
 // the way.
 //
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
+//nolint:paralleltest // the cases share cmd
 func TestInvalidSecretNameLeavesVaultsUnchanged(t *testing.T) {
 	// Creating a passphrase unlocker is slow by design, so the vaults are
 	// created once and each case runs on its own copy of them.
@@ -259,7 +269,7 @@ func TestInvalidSecretNameLeavesVaultsUnchanged(t *testing.T) {
 // `secret version rm x ""` every version of x. A version argument is
 // accepted only if it is one of the versions `secret version list` lists.
 //
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
+//nolint:paralleltest // the cases share cmd
 func TestInvalidVersionLeavesVaultsUnchanged(t *testing.T) {
 	before := snapshotStateDir(t, newTwoVaultFs(t))
 
@@ -297,15 +307,17 @@ func TestInvalidVersionLeavesVaultsUnchanged(t *testing.T) {
 // `secret vault import ..` wrote a long-term key and an unlocker into the
 // state directory itself, and `secret vault select ..` made it the current
 // vault. Each command that takes a vault name must reject an invalid one
-// before building a path from it. The mnemonic and the passphrase are set,
-// and moves and removals use --force, so that only the name check stands
-// in the way.
+// before building a path from it. The instance is given the mnemonic and
+// the passphrase, and moves and removals use --force, so that only the name
+// check stands in the way.
 //
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
+//nolint:paralleltest // the cases share cmd
 func TestInvalidVaultNameLeavesStateUnchanged(t *testing.T) {
 	before := snapshotStateDir(t, newTwoVaultFs(t))
 
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	mnemonic := testMnemonicBuffer(t)
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	t.Cleanup(passphrase.Destroy)
 
 	cmd := &cobra.Command{}
 
@@ -338,7 +350,12 @@ func TestInvalidVaultNameLeavesStateUnchanged(t *testing.T) {
 		for _, name := range []string{"", ".", "..", "a/b"} {
 			t.Run(fmt.Sprintf(tt.command, name), func(t *testing.T) {
 				requireRejectedAndUnchanged(t, before, vault.ValidateVaultName(name),
-					func(c *cli.Instance) error { return tt.run(c, name) })
+					func(c *cli.Instance) error {
+						c.Mnemonic = mnemonic
+						c.UnlockPassphrase = passphrase
+
+						return tt.run(c, name)
+					})
 			})
 		}
 	}
@@ -347,14 +364,16 @@ func TestInvalidVaultNameLeavesStateUnchanged(t *testing.T) {
 // TestRemoveVersionRemovesOnlyThatVersion checks that `secret version rm`
 // with a version that is not the current one removes that version and
 // changes nothing else.
-//
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
 func TestRemoveVersionRemovesOnlyThatVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := newTwoVaultFs(t)
 
 	vlt, err := vault.GetCurrentVault(fs, testStateDir)
 	require.NoError(t, err)
 
+	vlt.Mnemonic = testMnemonicBuffer(t)
+
 	// A second version of "x" becomes the current one.
 	err = vlt.AddSecret("x", memguard.NewBufferFromBytes([]byte("new")), true)
 	require.NoError(t, err)
@@ -388,9 +407,9 @@ func TestRemoveVersionRemovesOnlyThatVersion(t *testing.T) {
 // TestMoveToVaultNameRenamesInCurrentVault checks that `secret mv x work`,
 // where "work" is also the name of a vault, renames the secret "x" to "work"
 // in the current vault and changes nothing else.
-//
-//nolint:paralleltest // newTwoVaultFs uses t.Setenv
 func TestMoveToVaultNameRenamesInCurrentVault(t *testing.T) {
+	t.Parallel()
+
 	before := snapshotStateDir(t, newTwoVaultFs(t))
 	fs := newFsFromSnapshot(t, before)
 

internal/cli/secrets.go

@@ -81,6 +81,9 @@ func newAddCmd() *cobra.Command {
 
 			cli.cmd = cmd // Set the command for stdin access
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			secret.Debug("Created CLI instance, calling AddSecret")
 
 			return cli.AddSecret(args[0], force)
@@ -111,6 +114,9 @@ func newGetCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			// Without --version, get the current version. A given
 			// --version is checked as typed, so an empty one is rejected.
 			if !cmd.Flags().Changed("version") {
@@ -174,6 +180,9 @@ func newImportCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.ImportSecret(cmd, args[0], sourceFile, force)
 		},
 	}
@@ -248,6 +257,9 @@ The source secret is deleted after successful copy.`,
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.MoveSecret(cmd, args[0], args[1], force)
 		},
 	}
@@ -354,6 +366,8 @@ func (cli *Instance) AddSecret(secretName string, force bool) error {
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	secret.Debug("Got current vault", "vault_name", vlt.GetName())
 
 	// Read secret value directly into protected buffers
@@ -420,6 +434,8 @@ func (cli *Instance) GetSecret(cmd *cobra.Command, secretName string) error {
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	value, err := vlt.GetSecret(secretName)
 	if err != nil {
 		return err
@@ -448,6 +464,8 @@ func (cli *Instance) GetSecretWithVersion(
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Get the secret value
 	value, err := vlt.GetSecretVersion(secretName, version)
 	if err != nil {
@@ -633,6 +651,8 @@ func (cli *Instance) ImportSecret(
 		return err
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Read secret value from the source file into protected buffers
 	file, err := cli.fs.Open(sourceFile)
 	if err != nil {
@@ -993,6 +1013,10 @@ func (cli *Instance) moveSecretCrossVault(
 			destVault.Name, destSecretName)
 	}
 
+	// Copying needs the long-term keys of both vaults
+	srcVault.Mnemonic, srcVault.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+	destVault.Mnemonic, destVault.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Unlock destination vault (will fail if neither mnemonic nor unlocker available)
 	_, err = destVault.GetOrDeriveLongTermKey()
 	if err != nil {

internal/cli/secrets_size_test.go

@@ -10,7 +10,6 @@ import (
 	"strings"
 	"testing"
 
-	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"git.eeqj.de/sneak/secret/pkg/agehd"
 	"github.com/spf13/afero"
@@ -71,11 +70,8 @@ func newSizeTestVault(t *testing.T) (afero.Fs, *vault.Vault) {
 
 	fs := afero.NewMemMapFs()
 
-	// Set test mnemonic
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
 	// Create vault
-	_, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	_, err := vault.CreateVault(fs, testStateDir, testVaultName, testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	// Set current vault
@@ -205,7 +201,7 @@ func runImportSecretSizeCase(t *testing.T, size int, wantErr bool, errMsg string
 
 // TestAddSecretVariousSizes tests adding secrets of various sizes through stdin
 //
-//nolint:paralleltest // subtests use t.Setenv via newSizeTestVault
+//nolint:paralleltest // together the subtests lock more than the memlock limit
 func TestAddSecretVariousSizes(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -265,7 +261,7 @@ func TestAddSecretVariousSizes(t *testing.T) {
 
 // TestImportSecretVariousSizes tests importing secrets of various sizes from files
 //
-//nolint:paralleltest // subtests use t.Setenv via newSizeTestVault
+//nolint:paralleltest // together the subtests lock more than the memlock limit
 func TestImportSecretVariousSizes(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -325,7 +321,7 @@ func TestImportSecretVariousSizes(t *testing.T) {
 
 // TestAddSecretBufferGrowth tests that our buffer growth strategy works correctly
 //
-//nolint:paralleltest // subtests use t.Setenv via newSizeTestVault
+//nolint:paralleltest // together the subtests lock more than the memlock limit
 func TestAddSecretBufferGrowth(t *testing.T) {
 	// Test various sizes that should trigger buffer growth
 	sizes := []int{
@@ -392,9 +388,9 @@ func TestAddSecretBufferGrowth(t *testing.T) {
 }
 
 // TestAddSecretStreamingBehavior tests that we handle streaming input correctly
-//
-//nolint:paralleltest // uses t.Setenv via newSizeTestVault
 func TestAddSecretStreamingBehavior(t *testing.T) {
+	t.Parallel()
+
 	fs, vlt := newSizeTestVault(t)
 
 	// Create a custom reader that simulates slow streaming input

internal/cli/unlockers.go

@@ -16,7 +16,6 @@ import (
 
 	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
-	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 )
@@ -230,6 +229,9 @@ func newUnlockerAddCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			unlockerType := args[0]
 
 			// Validate unlocker type
@@ -580,19 +582,19 @@ func (cli *Instance) addPassphraseUnlocker(cmd *cobra.Command) error {
 	// For passphrase unlockers, we don't need the vault to be unlocked
 	// The CreatePassphraseUnlocker method will handle getting the
 	// long-term key
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
 
-	// Check if passphrase is set in environment variable
-	var passphraseBuffer *memguard.LockedBuffer
-	if envPassphrase := os.Getenv(secret.EnvUnlockPassphrase); envPassphrase != "" {
-		passphraseBuffer = memguard.NewBufferFromBytes([]byte(envPassphrase))
-	} else {
+	// The new unlocker gets the passphrase from the environment, which also
+	// unlocks the current passphrase unlocker, else the one entered here
+	passphraseBuffer := cli.UnlockPassphrase
+	if passphraseBuffer == nil {
 		// Use secure passphrase input with confirmation
 		passphraseBuffer, err = readSecurePassphrase("Enter passphrase for unlocker: ")
 		if err != nil {
 			return fmt.Errorf("failed to read passphrase: %w", err)
 		}
+		defer passphraseBuffer.Destroy()
 	}
-	defer passphraseBuffer.Destroy()
 
 	passphraseUnlocker, err := vlt.CreatePassphraseUnlocker(passphraseBuffer)
 	if err != nil {
@@ -613,7 +615,8 @@ func (cli *Instance) addKeychainUnlocker(cmd *cobra.Command) error {
 		return errKeychainMacOSOnly
 	}
 
-	keychainUnlocker, err := secret.CreateKeychainUnlocker(cli.fs, cli.stateDir)
+	keychainUnlocker, err := secret.CreateKeychainUnlocker(
+		cli.fs, cli.stateDir, cli.Mnemonic, cli.UnlockPassphrase)
 	if err != nil {
 		return fmt.Errorf("failed to create macOS Keychain unlocker: %w", err)
 	}
@@ -643,7 +646,8 @@ func (cli *Instance) addSecureEnclaveUnlocker(cmd *cobra.Command) error {
 		return errSecureEnclaveMacOSOnly
 	}
 
-	seUnlocker, err := secret.CreateSecureEnclaveUnlocker(cli.fs, cli.stateDir)
+	seUnlocker, err := secret.CreateSecureEnclaveUnlocker(
+		cli.fs, cli.stateDir, cli.Mnemonic, cli.UnlockPassphrase)
 	if err != nil {
 		return fmt.Errorf("failed to create Secure Enclave unlocker: %w", err)
 	}
@@ -707,8 +711,8 @@ func (cli *Instance) addPGPUnlocker(cmd *cobra.Command) error {
 		return fmt.Errorf("GPG key %s %w", gpgKeyID, errGPGKeyAlreadyUnlocker)
 	}
 
-	pgpUnlocker, err := secret.CreatePGPUnlocker(
-		cli.fs, cli.stateDir, gpgKeyID, fingerprint)
+	pgpUnlocker, err := secret.CreatePGPUnlocker(cli.fs, cli.stateDir,
+		gpgKeyID, fingerprint, cli.Mnemonic, cli.UnlockPassphrase)
 	if err != nil {
 		return err
 	}

internal/cli/unlockers_add_test.go

@@ -5,7 +5,6 @@ import (
 	"path/filepath"
 	"testing"
 
-	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
@@ -24,28 +23,31 @@ const (
 
 // TestAddPGPUnlocker adds a PGP unlocker for a throwaway GPG key to a vault
 // with a passphrase unlocker, getting the vault's long-term key from the
-// mnemonic or, with the mnemonic unset, from the passphrase unlocker. It
-// then reads a secret with neither the mnemonic nor the passphrase set, so
+// mnemonic or, with no mnemonic given, from the passphrase unlocker. It
+// then reads a secret with neither the mnemonic nor the passphrase given, so
 // through the new unlocker, which the add selects.
+//
+//nolint:paralleltest // t.Setenv (GNUPGHOME) forbids parallel tests
 func TestAddPGPUnlocker(t *testing.T) {
 	newTestGPGKey(t)
 
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	t.Cleanup(passphrase.Destroy)
+
 	tests := []struct {
 		name string
-		// mnemonic is the mnemonic set while the unlocker is added.
-		mnemonic string
+		// mnemonic is the mnemonic given while the unlocker is added, or nil.
+		mnemonic *memguard.LockedBuffer
 	}{
-		{"long-term key from the mnemonic", testMnemonic},
-		{"long-term key from the current unlocker", ""},
+		{"long-term key from the mnemonic", testMnemonicBuffer(t)},
+		{"long-term key from the current unlocker", nil},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			t.Setenv(secret.EnvMnemonic, testMnemonic)
-			t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
-
 			fs := afero.NewMemMapFs()
-			vlt, err := vault.CreateVault(fs, listTestStateDir, listTestVaultName)
+			vlt, err := vault.CreateVault(fs, listTestStateDir, listTestVaultName,
+				testMnemonicBuffer(t))
 			require.NoError(t, err)
 
 			err = vlt.AddSecret(addTestSecretName,
@@ -56,15 +58,13 @@ func TestAddPGPUnlocker(t *testing.T) {
 				memguard.NewBufferFromBytes([]byte(testPassphrase)))
 			require.NoError(t, err)
 
-			t.Setenv(secret.EnvMnemonic, test.mnemonic)
-
 			instance, cmd := newTestInstance(fs)
+			instance.Mnemonic = test.mnemonic
+			instance.UnlockPassphrase = passphrase
+
 			cmd.Flags().String("keyid", unreadableTestGPGUserID, "")
 			require.NoError(t, instance.UnlockersAdd(unlockerTypePGP, cmd))
 
-			t.Setenv(secret.EnvMnemonic, "")
-			t.Setenv(secret.EnvUnlockPassphrase, "")
-
 			reopened := vault.NewVault(fs, listTestStateDir, listTestVaultName)
 
 			current, err := reopened.GetCurrentUnlocker()

internal/cli/vault.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"log"
-	"os"
 	"path/filepath"
 	"slices"
 	"strings"
@@ -85,6 +84,9 @@ func newVaultCreateCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.CreateVault(cmd, args[0])
 		},
 	}
@@ -136,6 +138,9 @@ func newVaultImportCmd() *cobra.Command {
 				return fmt.Errorf("failed to initialize CLI: %w", err)
 			}
 
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.VaultImport(cmd, vaultName)
 		},
 	}
@@ -228,28 +233,14 @@ func (cli *Instance) ListVaults(cmd *cobra.Command, jsonOutput bool) error {
 	return nil
 }
 
-// setMnemonicEnv sets the mnemonic environment variable and returns a
-// function that restores the previous value
-func setMnemonicEnv(mnemonicStr string) func() {
-	originalMnemonic := os.Getenv(secret.EnvMnemonic)
-	_ = os.Setenv(secret.EnvMnemonic, mnemonicStr)
-
-	return func() {
-		if originalMnemonic != "" {
-			_ = os.Setenv(secret.EnvMnemonic, originalMnemonic)
-		} else {
-			_ = os.Unsetenv(secret.EnvMnemonic)
-		}
-	}
-}
-
-// resolvePassphrase returns the unlock passphrase from the environment or
-// prompts the user for it with confirmation
-func resolvePassphrase() (*memguard.LockedBuffer, error) {
-	if envPassphrase := os.Getenv(secret.EnvUnlockPassphrase); envPassphrase != "" {
+// resolvePassphrase returns the unlock passphrase from the environment,
+// cli.UnlockPassphrase, or prompts the user for it with confirmation. The
+// returned cleanup function must be deferred by the caller.
+func (cli *Instance) resolvePassphrase() (*memguard.LockedBuffer, func(), error) {
+	if cli.UnlockPassphrase != nil {
 		secret.Debug("Using unlock passphrase from environment variable")
 
-		return memguard.NewBufferFromBytes([]byte(envPassphrase)), nil
+		return cli.UnlockPassphrase, func() {}, nil
 	}
 
 	secret.Debug("Prompting user for unlock passphrase")
@@ -257,10 +248,10 @@ func resolvePassphrase() (*memguard.LockedBuffer, error) {
 	// Use secure passphrase input with confirmation
 	passphraseBuffer, err := readSecurePassphrase("Enter passphrase for unlocker: ")
 	if err != nil {
-		return nil, fmt.Errorf("failed to read passphrase: %w", err)
+		return nil, nil, fmt.Errorf("failed to read passphrase: %w", err)
 	}
 
-	return passphraseBuffer, nil
+	return passphraseBuffer, passphraseBuffer.Destroy, nil
 }
 
 // CreateVault creates a new vault
@@ -273,30 +264,13 @@ func (cli *Instance) CreateVault(cmd *cobra.Command, name string) error {
 	}
 	defer release()
 
-	// Get or prompt for mnemonic
-	var mnemonicStr string
-
-	if envMnemonic := os.Getenv(secret.EnvMnemonic); envMnemonic != "" {
-		secret.Debug("Using mnemonic from environment variable")
-
-		mnemonicStr = envMnemonic
-	} else {
-		secret.Debug("Prompting user for mnemonic phrase")
-		// Read mnemonic securely without echo
-		mnemonicBuffer, err := secret.ReadPassphrase(
-			"Enter your BIP39 mnemonic phrase: ")
-		if err != nil {
-			secret.Debug("Failed to read mnemonic from stdin", "error", err)
-
-			return fmt.Errorf("failed to read mnemonic: %w", err)
-		}
-		defer mnemonicBuffer.Destroy()
-
-		mnemonicStr = mnemonicBuffer.String()
-
-		fmt.Fprintln(os.Stderr) // Add newline after hidden input
+	mnemonic, cleanupMnemonic, err := cli.promptMnemonic()
+	if err != nil {
+		return err
 	}
+	defer cleanupMnemonic()
 
+	mnemonicStr := mnemonic.String()
 	if mnemonicStr == "" {
 		return errMnemonicEmpty
 	}
@@ -311,18 +285,14 @@ func (cli *Instance) CreateVault(cmd *cobra.Command, name string) error {
 
 	// Ask for the unlocker passphrase before creating the vault, so that
 	// stopping at the prompt leaves no vault without an unlocker behind
-	passphraseBuffer, err := resolvePassphrase()
+	passphraseBuffer, cleanupPassphrase, err := cli.resolvePassphrase()
 	if err != nil {
 		return err
 	}
-	defer passphraseBuffer.Destroy()
-
-	// Set mnemonic in environment for CreateVault to use
-	restoreMnemonicEnv := setMnemonicEnv(mnemonicStr)
-	defer restoreMnemonicEnv()
+	defer cleanupPassphrase()
 
 	// Create the vault - it will handle key derivation internally
-	vlt, err := vault.CreateVault(cli.fs, cli.stateDir, name)
+	vlt, err := vault.CreateVault(cli.fs, cli.stateDir, name, mnemonic)
 	if err != nil {
 		return err
 	}
@@ -412,11 +382,12 @@ func (cli *Instance) vaultImportPreflight(
 	}
 
 	// Get mnemonic from environment
-	mnemonic := os.Getenv(secret.EnvMnemonic)
-	if mnemonic == "" {
+	if cli.Mnemonic == nil {
 		return "", "", "", errMnemonicEnvNotSet
 	}
 
+	mnemonic := cli.Mnemonic.String()
+
 	// Validate the mnemonic
 	mnemonicWords := strings.Fields(mnemonic)
 	secret.Debug("Validating BIP39 mnemonic", "word_count", len(mnemonicWords))
@@ -539,17 +510,13 @@ func (cli *Instance) importMnemonic(cmd *cobra.Command, vaultName string) error
 	}
 
 	// Get passphrase from environment variable
-	passphraseStr := os.Getenv(secret.EnvUnlockPassphrase)
-	if passphraseStr == "" {
+	passphraseBuffer := cli.UnlockPassphrase
+	if passphraseBuffer == nil {
 		return errPassphraseEnvNotSet
 	}
 
 	secret.Debug("Using unlock passphrase from environment variable")
 
-	// Create secure buffer for passphrase
-	passphraseBuffer := memguard.NewBufferFromBytes([]byte(passphraseStr))
-	defer passphraseBuffer.Destroy()
-
 	// Unlock the vault with the derived long-term key
 	vlt.Unlock(ltIdentity)
 

internal/cli/version.go

@@ -54,6 +54,9 @@ func VersionCommands(cli *Instance) *cobra.Command {
 		Args:              cobra.ExactArgs(1),
 		ValidArgsFunction: getSecretNamesCompletionFunc(cli.fs, cli.stateDir),
 		RunE: func(cmd *cobra.Command, args []string) error {
+			destroySecrets := cli.readSecretEnv()
+			defer destroySecrets()
+
 			return cli.ListVersions(cmd, args[0])
 		},
 	}
@@ -172,6 +175,8 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 		currentVersion = ""
 	}
 
+	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
+
 	// Get long-term key for decrypting metadata
 	ltIdentity, err := vlt.GetOrDeriveLongTermKey()
 	if err != nil {

internal/cli/version_test.go

@@ -45,6 +45,17 @@ const (
 	testStateDir = "/test/state"
 )
 
+// testMnemonicBuffer returns testMnemonic in a locked buffer that is
+// destroyed when the test ends.
+func testMnemonicBuffer(t *testing.T) *memguard.LockedBuffer {
+	t.Helper()
+
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	t.Cleanup(mnemonic.Destroy)
+
+	return mnemonic
+}
+
 // Helper function to add a version of the "test/secret" secret to the
 // vault with proper buffer protection
 func addTestSecret(t *testing.T, vlt *vault.Vault, value []byte, force bool) {
@@ -61,11 +72,8 @@ func addTestSecret(t *testing.T, vlt *vault.Vault, value []byte, force bool) {
 func setupTestVault(t *testing.T, fs afero.Fs) {
 	t.Helper()
 
-	// Set mnemonic for testing
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
 	// Create vault
-	vlt, err := vault.CreateVault(fs, testStateDir, "default")
+	vlt, err := vault.CreateVault(fs, testStateDir, "default", testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	// Derive and store long-term key from mnemonic
@@ -83,11 +91,13 @@ func setupTestVault(t *testing.T, fs afero.Fs) {
 	require.NoError(t, err)
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestListVersionsCommand(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)
+	cli.Mnemonic = testMnemonicBuffer(t)
 
 	// Set up vault with long-term key
 	setupTestVault(t, fs)
@@ -96,6 +106,8 @@ func TestListVersionsCommand(t *testing.T) {
 	vlt, err := vault.GetCurrentVault(fs, stateDir)
 	require.NoError(t, err)
 
+	vlt.Mnemonic = cli.Mnemonic
+
 	addTestSecret(t, vlt, []byte("version-1"), false)
 
 	time.Sleep(10 * time.Millisecond)
@@ -139,8 +151,9 @@ func TestListVersionsCommand(t *testing.T) {
 	assert.Equal(t, 2, versionLines)
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestListVersionsNonExistentSecret(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)
@@ -161,8 +174,9 @@ func TestListVersionsNonExistentSecret(t *testing.T) {
 	assert.Contains(t, err.Error(), "not found")
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestPromoteVersionCommand(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)
@@ -174,6 +188,8 @@ func TestPromoteVersionCommand(t *testing.T) {
 	vlt, err := vault.GetCurrentVault(fs, stateDir)
 	require.NoError(t, err)
 
+	vlt.Mnemonic = testMnemonicBuffer(t)
+
 	addTestSecret(t, vlt, []byte("version-1"), false)
 
 	time.Sleep(10 * time.Millisecond)
@@ -224,8 +240,9 @@ func TestPromoteVersionCommand(t *testing.T) {
 	assert.Equal(t, []byte("version-1"), promoted.Bytes())
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestPromoteNonExistentVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)
@@ -252,11 +269,13 @@ func TestPromoteNonExistentVersion(t *testing.T) {
 	assert.Contains(t, err.Error(), "not found")
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestGetSecretWithVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)
+	cli.Mnemonic = testMnemonicBuffer(t)
 
 	// Set up vault with long-term key
 	setupTestVault(t, fs)
@@ -265,6 +284,8 @@ func TestGetSecretWithVersion(t *testing.T) {
 	vlt, err := vault.GetCurrentVault(fs, stateDir)
 	require.NoError(t, err)
 
+	vlt.Mnemonic = cli.Mnemonic
+
 	addTestSecret(t, vlt, []byte("version-1"), false)
 
 	time.Sleep(10 * time.Millisecond)
@@ -298,10 +319,12 @@ func TestGetSecretWithVersion(t *testing.T) {
 	assert.Equal(t, "version-1", buf.String())
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestGetSecretWritesBinaryValue(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	cli := NewCLIInstanceWithStateDir(fs, testStateDir)
+	cli.Mnemonic = testMnemonicBuffer(t)
 
 	setupTestVault(t, fs)
 
@@ -361,8 +384,9 @@ func TestVersionCommandStructure(t *testing.T) {
 	assert.Equal(t, "Promote a specific version to current", promoteCmd.Short)
 }
 
-//nolint:paralleltest // uses t.Setenv via setupTestVault
 func TestListVersionsEmptyOutput(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 	stateDir := testStateDir
 	cli := NewCLIInstanceWithStateDir(fs, stateDir)

internal/secret/atomic_test.go

@@ -219,7 +219,7 @@ func newVaultWithSecret(
 ) *vault.Vault {
 	t.Helper()
 
-	vlt, err := vault.CreateVault(fs, stateDir, name)
+	vlt, err := vault.CreateVault(fs, stateDir, name, testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	buffer := memguard.NewBufferFromBytes([]byte(value))
@@ -329,14 +329,14 @@ func TestRemoveDirAtomic(t *testing.T) {
 // named with 255 bytes, the most a file name may have, on the real
 // filesystem: the temporary directories they use must fit that limit too.
 func TestLongestNames(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	const longestName = 255
 
 	fs := afero.NewOsFs()
 	name := strings.Repeat("a", longestName)
 
-	vlt, err := vault.CreateVault(fs, t.TempDir(), name)
+	vlt, err := vault.CreateVault(fs, t.TempDir(), name, testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	value := memguard.NewBufferFromBytes([]byte("long"))
@@ -361,13 +361,13 @@ func TestLongestNames(t *testing.T) {
 // another vault, as a forced move between vaults does, and makes the last
 // step that completes the copy fail. The secret it was to replace must
 // still be there unchanged: it may go only once its replacement is whole.
-//
-//nolint:paralleltest // t.Setenv forbids t.Parallel
 func TestForcedCopyKeepsDestinationUntilReplaced(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	for _, tfs := range testFilesystems {
 		t.Run(tfs.name, func(t *testing.T) {
+			t.Parallel()
+
 			base, stateDir := tfs.open(t)
 			src := newVaultWithSecret(t, base, stateDir, "source", "new")
 			dest := newVaultWithSecret(t, base, stateDir, "dest", "old")
@@ -400,13 +400,13 @@ func TestForcedCopyKeepsDestinationUntilReplaced(t *testing.T) {
 // directory directly in secrets.d or in a versions directory. Those are
 // listed to find secrets and versions, so a temporary directory made there
 // would be listed while half-built, and one left by a crash would stay.
-//
-//nolint:paralleltest // t.Setenv forbids t.Parallel
 func TestTempDirsStayOutOfListings(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	for _, tfs := range testFilesystems {
 		t.Run(tfs.name, func(t *testing.T) {
+			t.Parallel()
+
 			base, stateDir := tfs.open(t)
 			newVaultWithSecret(t, base, stateDir, "default", "first")
 
@@ -419,6 +419,7 @@ func TestTempDirsStayOutOfListings(t *testing.T) {
 				return nil
 			}}
 			vlt := vault.NewVault(fs, stateDir, "default")
+			vlt.Mnemonic = testMnemonicBuffer(t)
 
 			value := memguard.NewBufferFromBytes([]byte("second"))
 			defer value.Destroy()
@@ -527,13 +528,13 @@ func TestVersionSaveFailureLeavesNothing(t *testing.T) {
 // unlocker again and checks, before each change this makes, that the file
 // naming the current one exists: a reader or a crash never finds it
 // missing.
-//
-//nolint:paralleltest // t.Setenv forbids t.Parallel
 func TestCurrentFilesNeverMissing(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	for _, tfs := range testFilesystems {
 		t.Run(tfs.name, func(t *testing.T) {
+			t.Parallel()
+
 			base, stateDir := tfs.open(t)
 			vlt := newVaultWithSecret(t, base, stateDir, testVaultName, "value")
 
@@ -625,11 +626,11 @@ func TestWriteFileAtomicTempFile(t *testing.T) {
 // anything, so that it never leaves a partial unlocker, nor breaks the one
 // it would replace.
 func TestPassphraseUnlockerGetsKeyFirst(t *testing.T) {
-	// No mnemonic, and no current unlocker to get the key from
-	t.Setenv(secret.EnvMnemonic, "")
+	t.Parallel()
 
+	// No mnemonic, and no current unlocker to get the key from
 	base := afero.NewMemMapFs()
-	_, err := vault.CreateVault(base, testVaultStateDir, testVaultName)
+	_, err := vault.CreateVault(base, testVaultStateDir, testVaultName, nil)
 	require.NoError(t, err)
 
 	fs := hookFs{Fs: base, before: func(_, path string) error {
@@ -650,17 +651,18 @@ func TestPassphraseUnlockerGetsKeyFirst(t *testing.T) {
 // creating a passphrase unlocker makes, that the unlocker's directory either
 // does not exist or holds all of its files: a crash or a failure at any point
 // leaves no partial unlocker.
-//
-//nolint:paralleltest // t.Setenv forbids t.Parallel
 func TestPassphraseUnlockerIsWholeOrAbsent(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Parallel()
 
 	files := []string{"pub.age", privKeyFile, "longterm.age", unlockerMetadataFile}
 
 	for _, tfs := range testFilesystems {
 		t.Run(tfs.name, func(t *testing.T) {
+			t.Parallel()
+
 			base, stateDir := tfs.open(t)
-			vlt, err := vault.CreateVault(base, stateDir, testVaultName)
+			vlt, err := vault.CreateVault(base, stateDir, testVaultName,
+				testMnemonicBuffer(t))
 			require.NoError(t, err)
 
 			vaultDir, err := vlt.GetDirectory()
@@ -683,8 +685,10 @@ func TestPassphraseUnlockerIsWholeOrAbsent(t *testing.T) {
 			passphrase := memguard.NewBufferFromBytes([]byte(unlockerPassphrase))
 			defer passphrase.Destroy()
 
-			_, err = vault.NewVault(fs, stateDir, testVaultName).
-				CreatePassphraseUnlocker(passphrase)
+			hooked := vault.NewVault(fs, stateDir, testVaultName)
+			hooked.Mnemonic = vlt.Mnemonic
+
+			_, err = hooked.CreatePassphraseUnlocker(passphrase)
 			require.NoError(t, err)
 			assert.ElementsMatch(t, files, dirNames(t, base, unlockerDir))
 		})

internal/secret/derivation_index_test.go

@@ -34,6 +34,8 @@ func (v *realVault) GetFilesystem() afero.Fs { return v.fs }
 func (v *realVault) AddSecret(string, *memguard.LockedBuffer, bool) error { panic("not used") }
 func (v *realVault) GetCurrentUnlocker() (Unlocker, error)                { panic("not used") }
 func (v *realVault) GetOrDeriveLongTermKey() (*age.X25519Identity, error) { panic("not used") }
+func (v *realVault) SetMnemonic(*memguard.LockedBuffer)                   { panic("not used") }
+func (v *realVault) SetUnlockPassphrase(*memguard.LockedBuffer)           { panic("not used") }
 func (v *realVault) CreatePassphraseUnlocker(*memguard.LockedBuffer) (*PassphraseUnlocker, error) {
 	panic("not used")
 }
@@ -59,6 +61,8 @@ func createRealVault(t *testing.T, fs afero.Fs, stateDir, name string, derivatio
 }
 
 func TestGetLongTermPrivateKeyUsesVaultDerivationIndex(t *testing.T) {
+	t.Parallel()
+
 	const testMnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 
 	// Derive expected keys at two different indices to prove they differ.
@@ -73,9 +77,10 @@ func TestGetLongTermPrivateKeyUsesVaultDerivationIndex(t *testing.T) {
 	fs := afero.NewMemMapFs()
 	vault := createRealVault(t, fs, "/state", "test-vault", 5)
 
-	t.Setenv(EnvMnemonic, testMnemonic)
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	defer mnemonic.Destroy()
 
-	result, err := getLongTermPrivateKey(fs, vault)
+	result, err := getLongTermPrivateKey(fs, vault, mnemonic, nil)
 	require.NoError(t, err)
 	defer result.Destroy()
 

internal/secret/keychainunlocker.go

@@ -239,12 +239,14 @@ func generateKeychainUnlockerName(vaultName string) (string, error) {
 	return fmt.Sprintf("secret-%s-%s-%s", vaultName, hostname, enrollmentDate), nil
 }
 
-// getLongTermPrivateKey retrieves the long-term private key either from environment or current unlocker
+// getLongTermPrivateKey derives the long-term private key from mnemonic when
+// it is not nil, else gets it through the current unlocker, which is given
+// passphrase when it is a passphrase unlocker.
 // Returns a LockedBuffer to ensure the private key is protected in memory
-func getLongTermPrivateKey(fs afero.Fs, vault VaultInterface) (*memguard.LockedBuffer, error) {
-	// Check if mnemonic is available in environment variable
-	envMnemonic := os.Getenv(EnvMnemonic)
-	if envMnemonic != "" {
+func getLongTermPrivateKey(
+	fs afero.Fs, vault VaultInterface, mnemonic, passphrase *memguard.LockedBuffer,
+) (*memguard.LockedBuffer, error) {
+	if mnemonic != nil {
 		// Read vault metadata to get the correct derivation index
 		vaultDir, err := vault.GetDirectory()
 		if err != nil {
@@ -263,7 +265,7 @@ func getLongTermPrivateKey(fs afero.Fs, vault VaultInterface) (*memguard.LockedB
 		}
 
 		// Use mnemonic with the vault's actual derivation index
-		ltIdentity, err := agehd.DeriveIdentity(envMnemonic, metadata.DerivationIndex)
+		ltIdentity, err := agehd.DeriveIdentity(mnemonic.String(), metadata.DerivationIndex)
 		if err != nil {
 			return nil, fmt.Errorf("failed to derive long-term key from mnemonic: %w", err)
 		}
@@ -278,6 +280,10 @@ func getLongTermPrivateKey(fs afero.Fs, vault VaultInterface) (*memguard.LockedB
 		return nil, fmt.Errorf("failed to get current unlocker: %w", err)
 	}
 
+	if passphraseUnlocker, ok := currentUnlocker.(*PassphraseUnlocker); ok {
+		passphraseUnlocker.Passphrase = passphrase
+	}
+
 	// Get the current unlocker identity
 	currentUnlockerIdentity, err := currentUnlocker.GetIdentity()
 	if err != nil {
@@ -322,8 +328,12 @@ func getLongTermPrivateKey(fs afero.Fs, vault VaultInterface) (*memguard.LockedB
 	return ltPrivKeyBuffer, nil
 }
 
-// CreateKeychainUnlocker creates a new keychain unlocker and stores it in the vault
-func CreateKeychainUnlocker(fs afero.Fs, stateDir string) (*KeychainUnlocker, error) {
+// CreateKeychainUnlocker creates a new keychain unlocker and stores it in the
+// vault. The long-term key comes from mnemonic when it is not nil, else from
+// the current unlocker, as getLongTermPrivateKey describes.
+func CreateKeychainUnlocker(
+	fs afero.Fs, stateDir string, mnemonic, passphrase *memguard.LockedBuffer,
+) (*KeychainUnlocker, error) {
 	// Check if we're on macOS
 	if err := checkMacOSAvailable(); err != nil {
 		return nil, err
@@ -376,7 +386,7 @@ func CreateKeychainUnlocker(fs afero.Fs, stateDir string) (*KeychainUnlocker, er
 	}
 
 	// Step 4: Get or derive the long-term private key
-	ltPrivKeyData, err := getLongTermPrivateKey(fs, vault)
+	ltPrivKeyData, err := getLongTermPrivateKey(fs, vault, mnemonic, passphrase)
 	if err != nil {
 		return nil, err
 	}

internal/secret/keychainunlocker_stub.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 
 	"filippo.io/age"
+	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 )
 
@@ -75,6 +76,8 @@ func (k *KeychainUnlocker) Remove() error {
 }
 
 // CreateKeychainUnlocker returns an error on non-Darwin platforms
-func CreateKeychainUnlocker(_ afero.Fs, _ string) (*KeychainUnlocker, error) {
+func CreateKeychainUnlocker(
+	_ afero.Fs, _ string, _, _ *memguard.LockedBuffer,
+) (*KeychainUnlocker, error) {
 	return nil, errKeychainNotSupported
 }

internal/secret/passphrase_test.go

@@ -19,6 +19,17 @@ import (
 const testMnemonic = "abandon abandon abandon abandon abandon abandon " +
 	"abandon abandon abandon abandon abandon about"
 
+// testMnemonicBuffer returns testMnemonic in a locked buffer that is
+// destroyed when the test ends.
+func testMnemonicBuffer(t *testing.T) *memguard.LockedBuffer {
+	t.Helper()
+
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	t.Cleanup(mnemonic.Destroy)
+
+	return mnemonic
+}
+
 // writeTestPublicKey writes the unlocker public key and verifies it exists.
 func writeTestPublicKey(
 	t *testing.T, fs afero.Fs, unlockerDir string, agePublicKey string,
@@ -163,7 +174,7 @@ func newTestPassphraseUnlocker(
 	return unlocker, ageIdentity, unlockerDir
 }
 
-//nolint:paralleltest // subtests share real-FS state and t.Setenv, order matters
+//nolint:paralleltest // subtests share real-FS state, order matters
 func TestPassphraseUnlockerWithRealFS(t *testing.T) {
 	// This test uses real filesystem
 	if os.Getenv("CI") == "true" {
@@ -195,38 +206,42 @@ func TestPassphraseUnlockerWithRealFS(t *testing.T) {
 		writeTestLongTermKey(t, fs, unlockerDir, agePublicKey)
 	})
 
-	// Set test environment variable (cleaned up automatically)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	defer passphrase.Destroy()
 
-	// Test getting identity from environment variable
-	t.Run("GetIdentityFromEnv", func(t *testing.T) {
-		identity, err := unlocker.GetIdentity()
-		if err != nil {
-			t.Fatalf("Failed to get identity from env: %v", err)
-		}
+	unlocker.Passphrase = passphrase
 
-		// Verify the identity matches what we expect
-		expectedPubKey := ageIdentity.Recipient().String()
+	// Test getting identity with the passphrase the unlocker was given,
+	// twice: using it must leave it intact for the next use
+	t.Run("GetIdentityWithPassphrase", func(t *testing.T) {
+		for range 2 {
+			identity, err := unlocker.GetIdentity()
+			if err != nil {
+				t.Fatalf("Failed to get identity with passphrase: %v", err)
+			}
 
-		actualPubKey := identity.Recipient().String()
-		if actualPubKey != expectedPubKey {
-			t.Errorf("Public key mismatch. Expected %s, got %s",
-				expectedPubKey, actualPubKey)
+			// Verify the identity matches what we expect
+			expectedPubKey := ageIdentity.Recipient().String()
+
+			actualPubKey := identity.Recipient().String()
+			if actualPubKey != expectedPubKey {
+				t.Errorf("Public key mismatch. Expected %s, got %s",
+					expectedPubKey, actualPubKey)
+			}
 		}
 	})
 
-	// Unset the environment variable to test interactive prompt
-	_ = os.Unsetenv(secret.EnvUnlockPassphrase)
+	unlocker.Passphrase = nil
 
 	// Test getting identity from prompt (this would require mocking the
 	// prompt). For real integration tests, we'd need a way to mock the
 	// passphrase input. Here we just verify the error is what we expect
 	// when no passphrase is available.
-	t.Run("GetIdentityWithoutEnv", func(t *testing.T) {
+	t.Run("GetIdentityWithoutPassphrase", func(t *testing.T) {
 		// This should fail since we're not in an interactive terminal
 		_, err := unlocker.GetIdentity()
 		if err == nil {
-			t.Errorf("Should have failed to get identity without passphrase env var")
+			t.Errorf("Should have failed to get identity without a passphrase")
 		}
 	})
 

internal/secret/passphraseunlocker.go

@@ -3,7 +3,6 @@ package secret
 import (
 	"fmt"
 	"log/slog"
-	"os"
 	"path/filepath"
 
 	"filippo.io/age"
@@ -135,28 +134,19 @@ func (p *PassphraseUnlocker) Remove() error {
 	return nil
 }
 
-// getPassphrase retrieves the passphrase from memory, environment, or
-// user input. Returns a LockedBuffer for secure memory handling
+// getPassphrase returns a copy of p.Passphrase, or else asks the user for
+// the passphrase. The caller must destroy the returned buffer.
 func (p *PassphraseUnlocker) getPassphrase() (*memguard.LockedBuffer, error) {
-	// First check if we already have the passphrase
 	if p.Passphrase != nil && p.Passphrase.IsAlive() {
 		Debug("Using in-memory passphrase", "unlocker_id", p.GetID())
-		// Return a copy of the passphrase buffer
-		return memguard.NewBufferFromBytes(p.Passphrase.Bytes()), nil
+		// Not NewBufferFromBytes, which would wipe p.Passphrase
+		passphrase := memguard.NewBuffer(p.Passphrase.Size())
+		passphrase.Copy(p.Passphrase.Bytes())
+
+		return passphrase, nil
 	}
 
-	Debug("No passphrase in memory, checking environment")
-	// Check environment variable for passphrase
-	passphraseStr := os.Getenv(EnvUnlockPassphrase)
-	if passphraseStr != "" {
-		Debug("Using passphrase from environment", "unlocker_id", p.GetID())
-		// Convert to secure buffer
-		secureBuffer := memguard.NewBufferFromBytes([]byte(passphraseStr))
-
-		return secureBuffer, nil
-	}
-
-	Debug("No passphrase in environment, prompting user")
+	Debug("No passphrase in memory, prompting user")
 	// Prompt for passphrase
 	secureBuffer, err := ReadPassphrase("Enter unlock passphrase: ")
 	if err != nil {

internal/secret/pgpunlock_test.go

@@ -227,8 +227,10 @@ Passphrase: ` + testPassphrase + `
 	// Test data
 	testMnemonic := "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	defer mnemonic.Destroy()
+
 	// Set test environment variables
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
 	t.Setenv(secret.EnvGPGKeyID, keyID)
 
 	// Set up vault structure for testing
@@ -244,7 +246,7 @@ Passphrase: ` + testPassphrase + `
 		defer timer.Stop()
 
 		// Create a test vault directory structure
-		vlt, err := vault.CreateVault(fs, stateDir, vaultName)
+		vlt, err := vault.CreateVault(fs, stateDir, vaultName, mnemonic)
 		if err != nil {
 			t.Fatalf("Failed to create vault: %v", err)
 		}
@@ -290,7 +292,7 @@ Passphrase: ` + testPassphrase + `
 		}
 
 		// Now create a PGP unlock key (this will use our custom GPGEncryptFunc)
-		pgpUnlocker, err := secret.CreatePGPUnlocker(fs, stateDir, keyID, fingerprint)
+		pgpUnlocker, err := secret.CreatePGPUnlocker(fs, stateDir, keyID, fingerprint, mnemonic, nil)
 		if err != nil {
 			t.Fatalf("Failed to create PGP unlock key: %v", err)
 		}

internal/secret/pgpunlocker.go

@@ -254,9 +254,12 @@ func pgpUnlockerDir(
 // fingerprint as ResolveGPGKeyFingerprint returns it, in the metadata.
 // Everything that can fail short of writing a file is done before anything
 // is written, and the files are written through WriteDir, so a failure
-// leaves no partial unlocker.
+// leaves no partial unlocker. The long-term key comes from mnemonic when it
+// is not nil, else from the current unlocker, which is given passphrase when
+// it is a passphrase unlocker.
 func CreatePGPUnlocker(
 	fs afero.Fs, stateDir, gpgKeyID, fingerprint string,
+	mnemonic, passphrase *memguard.LockedBuffer,
 ) (*PGPUnlocker, error) {
 	err := checkGPGAvailable()
 	if err != nil {
@@ -268,6 +271,10 @@ func CreatePGPUnlocker(
 		return nil, err
 	}
 
+	// The vault's GetOrDeriveLongTermKey, in step 2, uses both
+	vault.SetMnemonic(mnemonic)
+	vault.SetUnlockPassphrase(passphrase)
+
 	// Step 1: Generate a new age keypair for the PGP unlocker
 	ageIdentity, err := age.GenerateX25519Identity()
 	if err != nil {

internal/secret/pgpunlocker_test.go

@@ -41,12 +41,13 @@ func installFakeGPG(t *testing.T) {
 // getting the vault's long-term key, which used to come after part of the
 // unlocker was written, and asserts that nothing is written. Getting the key
 // fails because there is no mnemonic and no current unlocker.
+//
+//nolint:paralleltest // installFakeGPG uses t.Setenv
 func TestCreatePGPUnlockerFailureWritesNothing(t *testing.T) {
 	installFakeGPG(t)
-	t.Setenv(secret.EnvMnemonic, "")
 
 	base := afero.NewMemMapFs()
-	vlt, err := vault.CreateVault(base, testVaultStateDir, testVaultName)
+	vlt, err := vault.CreateVault(base, testVaultStateDir, testVaultName, nil)
 	require.NoError(t, err)
 
 	fs := hookFs{Fs: base, before: func(_, path string) error {
@@ -56,7 +57,7 @@ func TestCreatePGPUnlockerFailureWritesNothing(t *testing.T) {
 	}}
 
 	_, err = secret.CreatePGPUnlocker(
-		fs, testVaultStateDir, testGPGKeyID, testGPGFingerprint)
+		fs, testVaultStateDir, testGPGKeyID, testGPGFingerprint, nil, nil)
 	require.Error(t, err)
 
 	vaultDir, err := vlt.GetDirectory()

internal/secret/secret.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
-	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -36,6 +35,11 @@ type VaultInterface interface {
 	GetFilesystem() afero.Fs
 	GetCurrentUnlocker() (Unlocker, error)
 	GetOrDeriveLongTermKey() (*age.X25519Identity, error)
+	// SetMnemonic and SetUnlockPassphrase give GetOrDeriveLongTermKey the
+	// mnemonic to derive the long-term key from, and the passphrase for a
+	// current passphrase unlocker; nil for none.
+	SetMnemonic(mnemonic *memguard.LockedBuffer)
+	SetUnlockPassphrase(passphrase *memguard.LockedBuffer)
 	CreatePassphraseUnlocker(
 		passphrase *memguard.LockedBuffer) (*PassphraseUnlocker, error)
 }
@@ -77,9 +81,12 @@ func NewSecret(vault VaultInterface, name string) *Secret {
 	}
 }
 
-// GetValue retrieves and decrypts the current version's value using the
-// provided unlocker
-func (s *Secret) GetValue(unlocker Unlocker) (*memguard.LockedBuffer, error) {
+// GetValue retrieves and decrypts the current version's value, with the
+// vault's long-term key derived from mnemonic when it is not nil, else
+// obtained through unlocker
+func (s *Secret) GetValue(
+	unlocker Unlocker, mnemonic *memguard.LockedBuffer,
+) (*memguard.LockedBuffer, error) {
 	DebugWith("Getting secret value",
 		slog.String("secret_name", s.Name),
 		slog.String("vault_name", s.vault.GetName()),
@@ -114,9 +121,8 @@ func (s *Secret) GetValue(unlocker Unlocker) (*memguard.LockedBuffer, error) {
 	// Create version object
 	version := NewVersion(s.vault, s.Name, currentVersion)
 
-	// Check for SB_SECRET_MNEMONIC environment variable for direct decryption
-	if envMnemonic := os.Getenv(EnvMnemonic); envMnemonic != "" {
-		return s.getValueViaMnemonic(version, envMnemonic)
+	if mnemonic != nil {
+		return s.getValueViaMnemonic(version, mnemonic.String())
 	}
 
 	Debug("Using unlocker for vault access", "secret_name", s.Name)
@@ -210,11 +216,11 @@ func (s *Secret) Exists() (bool, error) {
 }
 
 // getValueViaMnemonic derives the vault's long-term key from the
-// mnemonic in the environment and decrypts the version value with it.
+// mnemonic and decrypts the version value with it.
 func (s *Secret) getValueViaMnemonic(
-	version *Version, envMnemonic string,
+	version *Version, mnemonic string,
 ) (*memguard.LockedBuffer, error) {
-	Debug("Using mnemonic from environment for direct long-term key derivation",
+	Debug("Using mnemonic for direct long-term key derivation",
 		"secret_name", s.Name)
 
 	// Get vault directory to read metadata
@@ -251,7 +257,7 @@ func (s *Secret) getValueViaMnemonic(
 	)
 
 	// Use mnemonic with the vault's derivation index from metadata
-	ltIdentity, err := agehd.DeriveIdentity(envMnemonic, metadata.DerivationIndex)
+	ltIdentity, err := agehd.DeriveIdentity(mnemonic, metadata.DerivationIndex)
 	if err != nil {
 		Debug("Failed to derive long-term key from mnemonic for secret",
 			"error", err, "secret_name", s.Name)

internal/secret/secret_test.go

@@ -2,6 +2,7 @@
 package secret
 
 import (
+	"encoding/json"
 	"errors"
 	"os"
 	"path/filepath"
@@ -22,7 +23,7 @@ const testMnemonicValue = "abandon abandon abandon abandon abandon abandon " +
 	"abandon abandon abandon abandon abandon about"
 
 var (
-	errMnemonicNotSet       = errors.New("SB_SECRET_MNEMONIC not set")
+	errMnemonicNotSet       = errors.New("mock vault has no mnemonic")
 	errNotImplementedInMock = errors.New("not implemented in mock")
 )
 
@@ -32,6 +33,7 @@ type MockVault struct {
 	fs              afero.Fs
 	directory       string
 	derivationIndex uint32
+	mnemonic        *memguard.LockedBuffer
 }
 
 func (m *MockVault) GetDirectory() (string, error) {
@@ -61,12 +63,11 @@ func (m *MockVault) AddSecret(name string, value *memguard.LockedBuffer, _ bool)
 	ltPubKeyPath := filepath.Join(m.directory, "pub.age")
 
 	// Derive long-term key using the vault's derivation index
-	mnemonic := os.Getenv(EnvMnemonic)
-	if mnemonic == "" {
+	if m.mnemonic == nil {
 		return errMnemonicNotSet
 	}
 
-	ltIdentity, err := agehd.DeriveIdentity(mnemonic, m.derivationIndex)
+	ltIdentity, err := agehd.DeriveIdentity(m.mnemonic.String(), m.derivationIndex)
 	if err != nil {
 		return err
 	}
@@ -111,6 +112,12 @@ func (m *MockVault) GetOrDeriveLongTermKey() (*age.X25519Identity, error) {
 	return nil, errNotImplementedInMock
 }
 
+func (m *MockVault) SetMnemonic(mnemonic *memguard.LockedBuffer) {
+	m.mnemonic = mnemonic
+}
+
+func (m *MockVault) SetUnlockPassphrase(_ *memguard.LockedBuffer) {}
+
 func (m *MockVault) CreatePassphraseUnlocker(
 	_ *memguard.LockedBuffer,
 ) (*PassphraseUnlocker, error) {
@@ -238,13 +245,13 @@ func verifySecretFiles(t *testing.T, fs afero.Fs, vaultDir, secretName string) {
 	}
 }
 
-//nolint:paralleltest // uses t.Setenv (process-global environment)
+//nolint:paralleltest // subtests share one vault, order matters
 func TestPerSecretKeyFunctionality(t *testing.T) {
 	// Create an in-memory filesystem for testing
 	fs := afero.NewMemMapFs()
 
-	// Set test mnemonic for direct encryption/decryption
-	t.Setenv(EnvMnemonic, testMnemonicValue)
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonicValue))
+	defer mnemonic.Destroy()
 
 	// Set up a test vault structure
 	baseDir := "/test-config/berlin.sneak.pkg.secret"
@@ -258,6 +265,7 @@ func TestPerSecretKeyFunctionality(t *testing.T) {
 		fs:              fs,
 		directory:       vaultDir,
 		derivationIndex: 0,
+		mnemonic:        mnemonic,
 	}
 
 	// Test data
@@ -314,26 +322,45 @@ func TestPerSecretKeyFunctionality(t *testing.T) {
 	})
 }
 
-func TestSecretGetValueWithEnvMnemonicUsesVaultDerivationIndex(t *testing.T) {
-	// This test demonstrates the bug where GetValue uses hardcoded index 0
-	// instead of the vault's actual derivation index when using environment mnemonic
+// TestSecretGetValueWithMnemonicUsesVaultDerivationIndex checks that
+// GetValue, given the mnemonic, derives the long-term key at the derivation
+// index in the vault's metadata. At index 0 it could not decrypt the secret,
+// which was encrypted to the key at index 1.
+func TestSecretGetValueWithMnemonicUsesVaultDerivationIndex(t *testing.T) {
+	t.Parallel()
 
-	// Set up test mnemonic
-	t.Setenv(EnvMnemonic, testMnemonicValue)
+	fs := afero.NewMemMapFs()
+	vaultDir := "/test-config/vaults.d/test-vault"
 
-	// Create temporary directory for vaults
-	fs := afero.NewOsFs()
-	tempDir, err := afero.TempDir(fs, "", "secret-test-")
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonicValue))
+	defer mnemonic.Destroy()
+
+	vlt := &MockVault{
+		name:            "test-vault",
+		fs:              fs,
+		directory:       vaultDir,
+		derivationIndex: 1,
+		mnemonic:        mnemonic,
+	}
+
+	metadata, err := json.Marshal(VaultMetadata{DerivationIndex: vlt.derivationIndex})
+	require.NoError(t, err)
+	require.NoError(t, fs.MkdirAll(vaultDir, DirPerms))
+
+	err = afero.WriteFile(
+		fs, filepath.Join(vaultDir, "vault-metadata.json"), metadata, FilePerms)
 	require.NoError(t, err)
 
-	defer func() {
-		_ = fs.RemoveAll(tempDir)
-	}()
+	secretName, secretValue := "x", "value"
 
-	stateDir := filepath.Join(tempDir, ".secret")
-	require.NoError(t, fs.MkdirAll(stateDir, 0o700))
+	err = vlt.AddSecret(secretName,
+		memguard.NewBufferFromBytes([]byte(secretValue)), false)
+	require.NoError(t, err)
 
-	// This test is now in the integration test file where it can use real vaults
-	// The bug is demonstrated there - see test31EnvMnemonicUsesVaultDerivationIndex
-	t.Log("This test demonstrates the bug in the integration test file")
+	value, err := NewSecret(vlt, secretName).GetValue(nil, mnemonic)
+	require.NoError(t, err)
+
+	defer value.Destroy()
+
+	require.Equal(t, secretValue, value.String())
 }

internal/secret/seunlocker_darwin.go

@@ -207,9 +207,12 @@ func generateSEKeyLabel(vaultName string) (string, error) {
 // CreateSecureEnclaveUnlocker creates a new SE unlocker.
 // The vault's long-term private key is encrypted directly by the Secure Enclave
 // using ECIES. No intermediate age keypair is used.
+// The long-term key comes from mnemonic when it is not nil, else from the
+// current unlocker, as getLongTermKeyForSE describes.
 func CreateSecureEnclaveUnlocker(
 	fs afero.Fs,
 	stateDir string,
+	mnemonic, passphrase *memguard.LockedBuffer,
 ) (*SecureEnclaveUnlocker, error) {
 	if err := checkMacOSAvailable(); err != nil {
 		return nil, err
@@ -236,7 +239,7 @@ func CreateSecureEnclaveUnlocker(
 	Debug("Created SE key", "label", seKeyLabel, "hash", seKeyHash)
 
 	// Step 2: Get the vault's long-term private key
-	ltPrivKeyData, err := getLongTermKeyForSE(fs, vault)
+	ltPrivKeyData, err := getLongTermKeyForSE(fs, vault, mnemonic, passphrase)
 	if err != nil {
 		return nil, fmt.Errorf(
 			"failed to get long-term private key: %w",
@@ -306,14 +309,15 @@ func CreateSecureEnclaveUnlocker(
 	}, nil
 }
 
-// getLongTermKeyForSE retrieves the vault's long-term private key
-// either from the mnemonic env var or by unlocking via the current unlocker.
+// getLongTermKeyForSE retrieves the vault's long-term private key, derived
+// from mnemonic when it is not nil, else through the current unlocker, which
+// is given passphrase when it is a passphrase unlocker.
 func getLongTermKeyForSE(
 	fs afero.Fs,
 	vault VaultInterface,
+	mnemonic, passphrase *memguard.LockedBuffer,
 ) (*memguard.LockedBuffer, error) {
-	envMnemonic := os.Getenv(EnvMnemonic)
-	if envMnemonic != "" {
+	if mnemonic != nil {
 		// Read vault metadata to get the correct derivation index
 		vaultDir, err := vault.GetDirectory()
 		if err != nil {
@@ -333,7 +337,7 @@ func getLongTermKeyForSE(
 
 		// Use mnemonic with the vault's actual derivation index
 		ltIdentity, err := agehd.DeriveIdentity(
-			envMnemonic,
+			mnemonic.String(),
 			metadata.DerivationIndex,
 		)
 
@@ -352,6 +356,10 @@ func getLongTermKeyForSE(
 		return nil, fmt.Errorf("failed to get current unlocker: %w", err)
 	}
 
+	if passphraseUnlocker, ok := currentUnlocker.(*PassphraseUnlocker); ok {
+		passphraseUnlocker.Passphrase = passphrase
+	}
+
 	currentIdentity, err := currentUnlocker.GetIdentity()
 	if err != nil {
 		return nil, fmt.Errorf(

internal/secret/seunlocker_stub.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 
 	"filippo.io/age"
+	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 )
 
@@ -80,6 +81,7 @@ func (s *SecureEnclaveUnlocker) Remove() error {
 func CreateSecureEnclaveUnlocker(
 	_ afero.Fs,
 	_ string,
+	_, _ *memguard.LockedBuffer,
 ) (*SecureEnclaveUnlocker, error) {
 	return nil, errSENotSupported
 }

internal/secret/seunlocker_stub_test.go

@@ -78,7 +78,7 @@ func TestCreateSecureEnclaveUnlockerReturnsError(t *testing.T) {
 
 	fs := afero.NewMemMapFs()
 
-	unlocker, err := CreateSecureEnclaveUnlocker(fs, "/tmp/test")
+	unlocker, err := CreateSecureEnclaveUnlocker(fs, "/tmp/test", nil, nil)
 	assert.Nil(t, unlocker)
 	require.Error(t, err)
 	require.ErrorIs(t, err, errSENotSupported)

internal/secret/version_test.go

@@ -91,6 +91,10 @@ func (m *MockVersionVault) GetOrDeriveLongTermKey() (*age.X25519Identity, error)
 	return nil, errNotImplementedInMock
 }
 
+func (m *MockVersionVault) SetMnemonic(_ *memguard.LockedBuffer) {}
+
+func (m *MockVersionVault) SetUnlockPassphrase(_ *memguard.LockedBuffer) {}
+
 func (m *MockVersionVault) CreatePassphraseUnlocker(
 	_ *memguard.LockedBuffer,
 ) (*secret.PassphraseUnlocker, error) {

internal/vault/integration_test.go

@@ -8,7 +8,6 @@ import (
 	"testing"
 
 	"filippo.io/age"
-	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"git.eeqj.de/sneak/secret/pkg/agehd"
 	"github.com/awnumar/memguard"
@@ -41,46 +40,49 @@ func deriveVaultIdentity(
 	return ltIdentity
 }
 
-//nolint:paralleltest // t.Setenv forbids parallel subtests
 func TestVaultWithRealFilesystem(t *testing.T) {
+	t.Parallel()
+
 	// Create a temporary directory for our tests
 	tempDir := t.TempDir()
 
 	// Use the real filesystem
 	fs := afero.NewOsFs()
 
-	// Set test environment variables
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
-
 	// Test currentvault file handling (plain file with relative path)
 	t.Run("CurrentVaultFileHandling", func(t *testing.T) {
+		t.Parallel()
 		testCurrentVaultFileHandling(t, fs, tempDir)
 	})
 
 	// Test secret operations with deeply nested paths
 	t.Run("DeepPathSecrets", func(t *testing.T) {
+		t.Parallel()
 		testDeepPathSecrets(t, fs, tempDir)
 	})
 
 	// Test key caching in GetOrDeriveLongTermKey
 	t.Run("KeyCaching", func(t *testing.T) {
+		t.Parallel()
 		testKeyCaching(t, fs, tempDir)
 	})
 
 	// Test vault name validation
 	t.Run("VaultNameValidation", func(t *testing.T) {
+		t.Parallel()
 		testVaultNameValidation(t, fs, tempDir)
 	})
 
 	// Test multiple vaults and switching between them
 	t.Run("MultipleVaults", func(t *testing.T) {
+		t.Parallel()
 		testMultipleVaults(t, fs, tempDir)
 	})
 
 	// Test adding a secret in one vault and verifying it's not visible in
 	// another
 	t.Run("VaultIsolation", func(t *testing.T) {
+		t.Parallel()
 		testVaultIsolation(t, fs, tempDir)
 	})
 }
@@ -96,7 +98,8 @@ func testCurrentVaultFileHandling(t *testing.T, fs afero.Fs, tempDir string) {
 	}
 
 	// Create a test vault
-	vlt, err := vault.CreateVault(fs, stateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, stateDir, testVaultName,
+		testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault: %v", err)
 	}
@@ -141,9 +144,10 @@ func testDeepPathSecrets(t *testing.T, fs afero.Fs, tempDir string) {
 		t.Fatalf("Failed to create state dir: %v", err)
 	}
 
-	// Create a test vault - CreateVault now handles public key when
-	// mnemonic is in env
-	vlt, err := vault.CreateVault(fs, stateDir, testVaultName)
+	// Create a test vault - CreateVault writes the public key derived from
+	// the mnemonic
+	vlt, err := vault.CreateVault(fs, stateDir, testVaultName,
+		testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault: %v", err)
 	}
@@ -216,9 +220,10 @@ func testKeyCaching(t *testing.T, fs afero.Fs, tempDir string) {
 		t.Fatalf("Failed to create state dir: %v", err)
 	}
 
-	// Create a test vault - CreateVault now handles public key when
-	// mnemonic is in env
-	vlt, err := vault.CreateVault(fs, stateDir, testVaultName)
+	// Create a test vault - CreateVault writes the public key derived from
+	// the mnemonic
+	vlt, err := vault.CreateVault(fs, stateDir, testVaultName,
+		testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault: %v", err)
 	}
@@ -319,7 +324,7 @@ func testVaultNameValidation(t *testing.T, fs afero.Fs, tempDir string) {
 	}
 
 	for _, name := range validNames {
-		_, err := vault.CreateVault(fs, stateDir, name)
+		_, err := vault.CreateVault(fs, stateDir, name, testMnemonicBuffer(t))
 		if err != nil {
 			t.Errorf("Failed to create vault with valid name %q: %v", name, err)
 		}
@@ -335,7 +340,7 @@ func testVaultNameValidation(t *testing.T, fs afero.Fs, tempDir string) {
 	}
 
 	for _, name := range invalidNames {
-		_, err := vault.CreateVault(fs, stateDir, name)
+		_, err := vault.CreateVault(fs, stateDir, name, testMnemonicBuffer(t))
 		if err == nil {
 			t.Errorf("Expected error creating vault with invalid name %q, "+
 				"but got none", name)
@@ -356,7 +361,7 @@ func testMultipleVaults(t *testing.T, fs afero.Fs, tempDir string) {
 	// Create three vaults
 	vaultNames := []string{"vault1", "vault2", "vault3"}
 	for _, name := range vaultNames {
-		_, err := vault.CreateVault(fs, stateDir, name)
+		_, err := vault.CreateVault(fs, stateDir, name, testMnemonicBuffer(t))
 		if err != nil {
 			t.Fatalf("Failed to create vault %s: %v", name, err)
 		}
@@ -404,14 +409,14 @@ func testVaultIsolation(t *testing.T, fs afero.Fs, tempDir string) {
 		t.Fatalf("Failed to create state dir: %v", err)
 	}
 
-	// Create two vaults - CreateVault now handles public key when mnemonic
-	// is in env
-	vault1, err := vault.CreateVault(fs, stateDir, "vault1")
+	// Create two vaults - CreateVault writes the public key derived from
+	// the mnemonic
+	vault1, err := vault.CreateVault(fs, stateDir, "vault1", testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault1: %v", err)
 	}
 
-	vault2, err := vault.CreateVault(fs, stateDir, "vault2")
+	vault2, err := vault.CreateVault(fs, stateDir, "vault2", testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault2: %v", err)
 	}

internal/vault/integration_version_test.go

@@ -44,15 +44,12 @@ var errUnexpectedValue = errors.New("unexpected value")
 
 // TestVersionIntegrationWorkflow tests the complete version workflow
 //
-//nolint:paralleltest // t.Setenv forbids parallel subtests
+//nolint:paralleltest // the subtests are steps that build on each other
 func TestVersionIntegrationWorkflow(t *testing.T) {
 	fs := afero.NewMemMapFs()
 
-	// Set mnemonic for testing
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-
-	// Create vault
-	vault, err := CreateVault(fs, testStateDir, "test")
+	// Create vault without a long-term key, which is set up below
+	vault, err := CreateVault(fs, testStateDir, "test", nil)
 	require.NoError(t, err)
 
 	// Derive and store long-term key from mnemonic
@@ -351,9 +348,9 @@ func testVersionErrorCases(t *testing.T, vault *Vault, secretName string) {
 }
 
 // TestVersionConcurrency tests concurrent version operations
-//
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVersionConcurrency(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Set up vault
@@ -366,6 +363,8 @@ func TestVersionConcurrency(t *testing.T) {
 
 	// Test concurrent reads
 	t.Run("concurrent_reads", func(t *testing.T) {
+		t.Parallel()
+
 		done := make(chan bool, 10)
 		errCh := make(chan error, 10)
 
@@ -403,9 +402,9 @@ func TestVersionConcurrency(t *testing.T) {
 }
 
 // TestVersionCompatibility tests that old secrets without versions still work
-//
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVersionCompatibility(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Set up vault

internal/vault/management.go

@@ -3,7 +3,6 @@ package vault
 
 import (
 	"fmt"
-	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -11,6 +10,7 @@ import (
 
 	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/pkg/agehd"
+	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 )
 
@@ -155,19 +155,18 @@ func ListVaults(fs afero.Fs, stateDir string) ([]string, error) {
 // It returns the derivation index, public key hash, and family hash.
 func processMnemonicForVault(
 	fs afero.Fs, stateDir, vaultDir, vaultName string,
+	mnemonicBuffer *memguard.LockedBuffer,
 ) (uint32, string, string, error) {
-	// Check if mnemonic is available in environment
-	mnemonic := os.Getenv(secret.EnvMnemonic)
-
-	if mnemonic == "" {
-		secret.Debug("No mnemonic in environment, vault created without long-term key",
+	if mnemonicBuffer == nil {
+		secret.Debug("No mnemonic given, vault created without long-term key",
 			"vault", vaultName)
 		// Use 0 for derivation index when no mnemonic is provided
 		return 0, "", "", nil
 	}
 
-	secret.Debug("Mnemonic found in environment, deriving long-term key",
-		"vault", vaultName)
+	mnemonic := mnemonicBuffer.String()
+
+	secret.Debug("Mnemonic given, deriving long-term key", "vault", vaultName)
 
 	// Get the next available derivation index for this mnemonic
 	derivationIndex, err := GetNextDerivationIndex(fs, stateDir, mnemonic)
@@ -208,12 +207,17 @@ func processMnemonicForVault(
 	return derivationIndex, publicKeyHash, familyHash, nil
 }
 
-// CreateVault creates a new vault and selects it as the current vault. It
-// refuses a vault that already exists before writing anything: creating it
-// again would replace its keys, and its secrets could no longer be
-// decrypted. The commands that call it hold the state directory lock, so no
-// other command can create the vault between the check and the writes.
-func CreateVault(fs afero.Fs, stateDir string, name string) (*Vault, error) {
+// CreateVault creates a new vault and selects it as the current vault. When
+// mnemonic is not nil, the vault's long-term key is derived from it, and the
+// returned vault has it as its Mnemonic; when it is nil, the vault has no
+// long-term key until one is imported. It refuses a vault that already
+// exists before writing anything: creating it again would replace its keys,
+// and its secrets could no longer be decrypted. The commands that call it
+// hold the state directory lock, so no other command can create the vault
+// between the check and the writes.
+func CreateVault(
+	fs afero.Fs, stateDir string, name string, mnemonic *memguard.LockedBuffer,
+) (*Vault, error) {
 	secret.Debug("Creating new vault", "name", name, "state_dir", stateDir)
 
 	err := ValidateVaultName(name)
@@ -263,7 +267,7 @@ func CreateVault(fs afero.Fs, stateDir string, name string) (*Vault, error) {
 
 	// Process mnemonic if available
 	derivationIndex, publicKeyHash, familyHash, err := processMnemonicForVault(
-		fs, stateDir, vaultDir, name)
+		fs, stateDir, vaultDir, name, mnemonic)
 	if err != nil {
 		return nil, err
 	}
@@ -292,7 +296,10 @@ func CreateVault(fs afero.Fs, stateDir string, name string) (*Vault, error) {
 	// Create and return the vault
 	secret.Debug("Successfully created vault", "name", name)
 
-	return NewVault(fs, stateDir, name), nil
+	vlt := NewVault(fs, stateDir, name)
+	vlt.Mnemonic = mnemonic
+
+	return vlt, nil
 }
 
 // SelectVault selects the given vault as the current vault

internal/vault/metadata_test.go

@@ -297,14 +297,14 @@ func TestSampleHashCalculation(t *testing.T) {
 }
 
 func TestWorkflowMismatch(t *testing.T) {
+	t.Parallel()
+
 	// Create a temporary directory for testing
 	tempDir := t.TempDir()
 	fs := afero.NewOsFs()
 
 	// Test Case 1: Create vault WITH mnemonic (like init command)
-	t.Setenv("SB_SECRET_MNEMONIC", testMnemonic)
-
-	_, err := vault.CreateVault(fs, tempDir, "default")
+	_, err := vault.CreateVault(fs, tempDir, "default", testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault with mnemonic: %v", err)
 	}
@@ -321,19 +321,15 @@ func TestWorkflowMismatch(t *testing.T) {
 		metadata1.DerivationIndex, metadata1.PublicKeyHash)
 
 	// Test Case 2: Create vault WITHOUT mnemonic, then import (work vault)
-	t.Setenv("SB_SECRET_MNEMONIC", "")
-
-	_, err = vault.CreateVault(fs, tempDir, "work")
+	_, err = vault.CreateVault(fs, tempDir, "work", nil)
 	if err != nil {
 		t.Fatalf("Failed to create vault without mnemonic: %v", err)
 	}
 
 	vault2Dir := filepath.Join(tempDir, "vaults.d", "work")
 
-	// Simulate the vault import process
-	t.Setenv("SB_SECRET_MNEMONIC", testMnemonic)
-
-	// Get the next available derivation index for this mnemonic
+	// Simulate the vault import process: get the next available derivation
+	// index for this mnemonic
 	derivationIndex, err := vault.GetNextDerivationIndex(fs, tempDir, testMnemonic)
 	if err != nil {
 		t.Fatalf("Failed to get next derivation index: %v", err)

internal/vault/path_traversal_test.go

@@ -3,7 +3,6 @@ package vault_test
 import (
 	"testing"
 
-	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
@@ -13,15 +12,13 @@ import (
 // TestGetSecretVersionRejectsPathTraversal verifies that GetSecretVersion
 // validates the secret name and rejects path traversal attempts.
 // This is a regression test for https://git.eeqj.de/sneak/secret/issues/13
-//
-//nolint:paralleltest // t.Setenv in parent forbids parallel subtests
 func TestGetSecretVersionRejectsPathTraversal(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	t.Parallel()
 
 	fs := afero.NewMemMapFs()
 
-	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName,
+		testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	// Add a legitimate secret so the vault is set up
@@ -41,6 +38,8 @@ func TestGetSecretVersionRejectsPathTraversal(t *testing.T) {
 
 	for _, name := range maliciousNames {
 		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
 			_, err := vlt.GetSecretVersion(name, "")
 			require.Error(t, err,
 				"GetSecretVersion should reject malicious name: %s", name)
@@ -53,12 +52,12 @@ func TestGetSecretVersionRejectsPathTraversal(t *testing.T) {
 // TestGetSecretRejectsPathTraversal verifies GetSecret (which calls
 // GetSecretVersion) also rejects path traversal names.
 func TestGetSecretRejectsPathTraversal(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	t.Parallel()
 
 	fs := afero.NewMemMapFs()
 
-	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName,
+		testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	_, err = vlt.GetSecret("../../../etc/passwd")
@@ -68,15 +67,13 @@ func TestGetSecretRejectsPathTraversal(t *testing.T) {
 
 // TestGetSecretObjectRejectsPathTraversal verifies GetSecretObject
 // also validates names and rejects path traversal attempts.
-//
-//nolint:paralleltest // t.Setenv in parent forbids parallel subtests
 func TestGetSecretObjectRejectsPathTraversal(t *testing.T) {
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	t.Parallel()
 
 	fs := afero.NewMemMapFs()
 
-	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName,
+		testMnemonicBuffer(t))
 	require.NoError(t, err)
 
 	maliciousNames := []string{
@@ -87,6 +84,8 @@ func TestGetSecretObjectRejectsPathTraversal(t *testing.T) {
 
 	for _, name := range maliciousNames {
 		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
 			_, err := vlt.GetSecretObject(name)
 			require.Error(t, err, "GetSecretObject should reject: %s", name)
 			require.Contains(t, err.Error(), "invalid secret name")

internal/vault/secrets_version_test.go

@@ -41,14 +41,6 @@ import (
 const testMnemonic = "abandon abandon abandon abandon abandon abandon abandon " +
 	"abandon abandon abandon abandon about"
 
-// envTestMnemonic is the (deliberately different) mnemonic placed in the
-// environment; the vault is unlocked manually with the derived key in
-// createTestVaultWithKey.
-//
-//nolint:dupword // BIP39-style test mnemonic intentionally repeats a word
-const envTestMnemonic = "abandon abandon abandon abandon abandon abandon " +
-	"abandon abandon abandon about"
-
 // Shared fixtures for white-box tests in this package.
 const (
 	testStateDir   = "/test/state"
@@ -73,11 +65,8 @@ func addTestSecretToVault(
 func createTestVaultWithKey(t *testing.T, fs afero.Fs) *Vault {
 	t.Helper()
 
-	// Set mnemonic for testing
-	t.Setenv(secret.EnvMnemonic, envTestMnemonic)
-
-	// Create vault
-	vault, err := CreateVault(fs, testStateDir, "test")
+	// Create vault without a long-term key, which is set up below
+	vault, err := CreateVault(fs, testStateDir, "test", nil)
 	require.NoError(t, err)
 
 	// Derive and store long-term key from mnemonic
@@ -98,8 +87,9 @@ func createTestVaultWithKey(t *testing.T, fs afero.Fs) *Vault {
 	return vault
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVaultAddSecretCreatesVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key
@@ -137,8 +127,9 @@ func TestVaultAddSecretCreatesVersion(t *testing.T) {
 	assert.Equal(t, expectedValue, retrievedValue.Bytes())
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVaultAddSecretMultipleVersions(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key
@@ -174,8 +165,9 @@ func TestVaultAddSecretMultipleVersions(t *testing.T) {
 	assert.Equal(t, []byte("version-2"), value.Bytes())
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVaultGetSecretVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key
@@ -220,8 +212,9 @@ func TestVaultGetSecretVersion(t *testing.T) {
 	require.ErrorIs(t, err, ErrVersionNotFound)
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVaultVersionTimestamps(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key
@@ -303,8 +296,9 @@ func TestVaultVersionTimestamps(t *testing.T) {
 	assert.Nil(t, secondVersion.Metadata.NotAfter) // Current version
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestVaultGetNonExistentVersion(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key
@@ -319,8 +313,9 @@ func TestVaultGetNonExistentVersion(t *testing.T) {
 	assert.Contains(t, err.Error(), "not found")
 }
 
-//nolint:paralleltest // createTestVaultWithKey uses t.Setenv
 func TestUpdateVersionMetadata(t *testing.T) {
+	t.Parallel()
+
 	fs := afero.NewMemMapFs()
 
 	// Create vault with long-term key

internal/vault/unlockers.go

@@ -70,7 +70,9 @@ func (v *Vault) GetCurrentUnlocker() (secret.Unlocker, error) {
 		secret.Debug("Creating passphrase unlocker instance",
 			"unlocker_type", metadata.Type)
 
-		unlocker = secret.NewPassphraseUnlocker(v.fs, unlockerDir, metadata)
+		passphraseUnlocker := secret.NewPassphraseUnlocker(v.fs, unlockerDir, metadata)
+		passphraseUnlocker.Passphrase = v.UnlockPassphrase
+		unlocker = passphraseUnlocker
 	case "pgp":
 		secret.Debug("Creating PGP unlocker instance", "unlocker_type", metadata.Type)
 

internal/vault/vault.go

@@ -3,12 +3,12 @@ package vault
 import (
 	"fmt"
 	"log/slog"
-	"os"
 	"path/filepath"
 
 	"filippo.io/age"
 	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/pkg/agehd"
+	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 )
 
@@ -18,6 +18,13 @@ type Vault struct {
 	fs          afero.Fs
 	stateDir    string
 	longTermKey *age.X25519Identity // In-memory long-term key when unlocked
+	// Mnemonic, when not nil, is what the long-term key is derived from
+	// instead of the current unlocker. The caller destroys it.
+	Mnemonic *memguard.LockedBuffer
+	// UnlockPassphrase, when not nil, is given to the current unlocker
+	// when that is a passphrase unlocker, which otherwise prompts for it.
+	// The caller destroys it.
+	UnlockPassphrase *memguard.LockedBuffer
 }
 
 // NewVault creates a new Vault instance
@@ -56,6 +63,18 @@ func (v *Vault) ClearLongTermKey() {
 	v.longTermKey = nil
 }
 
+// SetMnemonic sets v.Mnemonic, for code that has v only as a
+// secret.VaultInterface.
+func (v *Vault) SetMnemonic(mnemonic *memguard.LockedBuffer) {
+	v.Mnemonic = mnemonic
+}
+
+// SetUnlockPassphrase sets v.UnlockPassphrase, for code that has v only as
+// a secret.VaultInterface.
+func (v *Vault) SetUnlockPassphrase(passphrase *memguard.LockedBuffer) {
+	v.UnlockPassphrase = passphrase
+}
+
 // GetOrDeriveLongTermKey gets the long-term key from memory or derives it
 // from available sources
 func (v *Vault) GetOrDeriveLongTermKey() (*age.X25519Identity, error) {
@@ -66,9 +85,8 @@ func (v *Vault) GetOrDeriveLongTermKey() (*age.X25519Identity, error) {
 
 	secret.Debug("Vault is locked, attempting to unlock", "vault_name", v.Name)
 
-	// Try to derive from environment mnemonic first
-	if envMnemonic := os.Getenv(secret.EnvMnemonic); envMnemonic != "" {
-		return v.deriveLongTermKeyFromMnemonic(envMnemonic)
+	if v.Mnemonic != nil {
+		return v.deriveLongTermKeyFromMnemonic(v.Mnemonic.String())
 	}
 
 	// No mnemonic available, try to use current unlocker
@@ -181,9 +199,9 @@ func (v *Vault) NumSecrets() (int, error) {
 // deriveLongTermKeyFromMnemonic derives the long-term key from the given
 // mnemonic, verifies it against the vault metadata, and caches it in memory.
 func (v *Vault) deriveLongTermKeyFromMnemonic(
-	envMnemonic string,
+	mnemonic string,
 ) (*age.X25519Identity, error) {
-	secret.Debug("Using mnemonic from environment for long-term key derivation",
+	secret.Debug("Using mnemonic for long-term key derivation",
 		"vault_name", v.Name)
 
 	// Load vault metadata to get the derivation index
@@ -199,7 +217,7 @@ func (v *Vault) deriveLongTermKeyFromMnemonic(
 		return nil, fmt.Errorf("failed to load vault metadata: %w", err)
 	}
 
-	ltIdentity, err := agehd.DeriveIdentity(envMnemonic, metadata.DerivationIndex)
+	ltIdentity, err := agehd.DeriveIdentity(mnemonic, metadata.DerivationIndex)
 	if err != nil {
 		secret.Debug("Failed to derive long-term key from mnemonic",
 			"error", err, "vault_name", v.Name)

internal/vault/vault_test.go

@@ -27,12 +27,19 @@ const (
 	testPassphrase = "test-passphrase"
 )
 
-//nolint:paralleltest // t.Setenv and order-dependent subtests forbid parallel
-func TestVaultOperations(t *testing.T) {
-	// Test environment will be cleaned up automatically by t.Setenv
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+// testMnemonicBuffer returns testMnemonic in a locked buffer that is
+// destroyed when the test ends.
+func testMnemonicBuffer(t *testing.T) *memguard.LockedBuffer {
+	t.Helper()
 
+	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
+	t.Cleanup(mnemonic.Destroy)
+
+	return mnemonic
+}
+
+//nolint:paralleltest // order-dependent subtests forbid parallel
+func TestVaultOperations(t *testing.T) {
 	// Use in-memory filesystem
 	fs := afero.NewMemMapFs()
 
@@ -64,7 +71,8 @@ func TestVaultOperations(t *testing.T) {
 func testCreateVault(t *testing.T, fs afero.Fs) {
 	t.Helper()
 
-	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName,
+		testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault: %v", err)
 	}
@@ -221,6 +229,8 @@ func testUnlockerOperations(t *testing.T, fs afero.Fs) {
 	}
 
 	// Test vault unlocking (should happen automatically via mnemonic)
+	vlt.Mnemonic = testMnemonicBuffer(t)
+
 	if vlt.Locked() {
 		_, err := vlt.UnlockVault()
 		if err != nil {
@@ -281,15 +291,14 @@ func testUnlockerOperations(t *testing.T, fs afero.Fs) {
 }
 
 func TestListUnlockers_SkipsMissingMetadata(t *testing.T) {
-	// Set test environment variables
-	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	t.Parallel()
 
 	// Use in-memory filesystem
 	fs := afero.NewMemMapFs()
 
 	// Create vault
-	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName,
+		testMnemonicBuffer(t))
 	if err != nil {
 		t.Fatalf("Failed to create vault: %v", err)
 	}