TODO.md

@@ -18,6 +18,18 @@ https://git.eeqj.de/sneak/secret/milestone/12
 
 # Completed Steps
 
+- 2026-10-04: A mnemonic that cannot be read, in `secret init` and
+  `secret vault create`, gives an error that names the mnemonic only
+  (https://git.eeqj.de/sneak/secret/issues/115). It is read with
+  `secret.ReadMnemonic`, whose every error wraps the new
+  `secret.ErrMnemonicNotRead`; before, it was read with `ReadPassphrase`, so
+  the message said "failed to read mnemonic: failed to read passphrase:" and
+  advised setting `SB_UNLOCK_PASSPHRASE`. Without a terminal it now says
+  "failed to read mnemonic: stdin is not a terminal (piped input or script).
+  Please set the SB_SECRET_MNEMONIC environment variable or run
+  interactively". The passphrase messages no longer repeat "cannot read
+  passphrase" after "failed to read passphrase:", and empty input gives
+  "nothing was entered".
 - 2026-10-04: A failure returns the same error value whichever command hits
   it (https://git.eeqj.de/sneak/secret/issues/113). `internal/cli` no longer
   keeps its own copies of `vault.ErrSecretNotFound`, `ErrVaultNotFound`,

internal/cli/create_vault_test.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"maps"
 	"os"
+	"os/exec"
 	"slices"
 	"strings"
 	"testing"
@@ -194,6 +195,37 @@ func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
 	}
 }
 
+// TestMnemonicNotReadNamesOnlyMnemonic is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/115: `secret init` without
+// SB_SECRET_MNEMONIC and with a stdin that is not a terminal said "failed to
+// read mnemonic: failed to read passphrase: ...". The error must wrap
+// secret.ErrMnemonicNotRead and name the mnemonic only. The message is
+// pinned on the built binary, whose stdin is surely not a terminal.
+func TestMnemonicNotReadNamesOnlyMnemonic(t *testing.T) {
+	t.Parallel()
+
+	c := cli.NewCLIInstanceWithStateDir(afero.NewMemMapFs(), testStateDir)
+	require.ErrorIs(t, c.Init(discardCmd()), secret.ErrMnemonicNotRead)
+
+	stateDir := t.TempDir()
+
+	//nolint:gosec // G204: test executes the freshly built secret binary
+	cmd := exec.CommandContext(t.Context(), secretBinaryPath(t), "init")
+	cmd.Env = []string{
+		secret.EnvStateDir + "=" + stateDir,
+		"PATH=" + os.Getenv("PATH"),
+		"HOME=" + os.Getenv("HOME"),
+	}
+
+	output, err := cmd.CombinedOutput()
+	require.Error(t, err)
+
+	require.Equal(t, "Initialized secrets manager at: "+stateDir+"\n"+
+		"Error: failed to read mnemonic: stdin is not a terminal (piped input "+
+		"or script). Please set the SB_SECRET_MNEMONIC environment variable "+
+		"or run interactively\n", string(output))
+}
+
 // TestStopDuringCreateLeavesWholeVaultOrNone is a regression test for
 // https://git.eeqj.de/sneak/secret/issues/105: `secret init` or `secret vault
 // create` killed after the passphrase prompt but before the unlocker was

internal/cli/init.go

@@ -55,11 +55,11 @@ func (cli *Instance) promptMnemonic() (*memguard.LockedBuffer, func(), error) {
 	secret.Debug("Prompting user for mnemonic phrase")
 
 	// Read mnemonic securely without echo
-	mnemonicBuffer, err := secret.ReadPassphrase("Enter your BIP39 mnemonic phrase: ")
+	mnemonicBuffer, err := secret.ReadMnemonic("Enter your BIP39 mnemonic phrase: ")
 	if err != nil {
 		secret.Debug("Failed to read mnemonic from stdin", "error", err)
 
-		return nil, nil, fmt.Errorf("failed to read mnemonic: %w", err)
+		return nil, nil, err
 	}
 
 	fmt.Fprintln(os.Stderr) // Add newline after hidden input

internal/cli/unlock_failure_test.go

@@ -260,9 +260,9 @@ func TestPassphraseNotReadNamesNoMnemonic(t *testing.T) {
 
 	assert.Equal(t, "Error: failed to unlock vault: "+
 		"failed to get long-term key: failed to get unlocker identity: "+
-		"failed to read passphrase: cannot read passphrase from non-terminal "+
-		"stdin (piped input or script). Please set the SB_UNLOCK_PASSPHRASE "+
-		"environment variable or run interactively\n", string(output))
+		"failed to read passphrase: stdin is not a terminal (piped input or "+
+		"script). Please set the SB_UNLOCK_PASSPHRASE environment variable or "+
+		"run interactively\n", string(output))
 }
 
 // TestCryptoUnlockFailureNamesMnemonic checks that `secret encrypt` and

internal/secret/crypto.go

@@ -17,16 +17,17 @@ import (
 var (
 	errNilPassphraseBuffer = errors.New("passphrase buffer is nil")
 	errStdinNotTerminal    = errors.New(
-		"cannot read passphrase from non-terminal stdin " +
-			"(piped input or script). Please set the SB_UNLOCK_PASSPHRASE " +
-			"environment variable or run interactively")
+		"stdin is not a terminal (piped input or script)")
 	errStderrNotTerminal = errors.New(
-		"cannot prompt for passphrase: stderr is not a terminal " +
-			"(running in non-interactive mode). Please set the " +
-			"SB_UNLOCK_PASSPHRASE environment variable")
+		"stderr is not a terminal (running in non-interactive mode)")
+	errNothingEntered  = errors.New("nothing was entered")
 	errEmptyPassphrase = errors.New("passphrase cannot be empty")
 )
 
+// ErrMnemonicNotRead is wrapped in every error of ReadMnemonic: there is no
+// terminal to read the mnemonic from, reading it failed, or it was empty.
+var ErrMnemonicNotRead = errors.New("failed to read mnemonic")
+
 // EncryptToRecipient encrypts data to a recipient using age
 // The data parameter should be a LockedBuffer for secure memory handling
 func EncryptToRecipient(
@@ -169,40 +170,58 @@ func DecryptWithPassphrase(
 // Returns a LockedBuffer containing the passphrase for secure memory handling.
 // Every error it returns wraps ErrPassphraseNotRead.
 func ReadPassphrase(prompt string) (*memguard.LockedBuffer, error) {
+	return readFromTerminal(prompt, ErrPassphraseNotRead, EnvUnlockPassphrase)
+}
+
+// ReadMnemonic reads a mnemonic from the terminal as ReadPassphrase reads a
+// passphrase. Every error it returns wraps ErrMnemonicNotRead.
+func ReadMnemonic(prompt string) (*memguard.LockedBuffer, error) {
+	return readFromTerminal(prompt, ErrMnemonicNotRead, EnvMnemonic)
+}
+
+// readFromTerminal reads input from the terminal without echoing it. Every
+// error it returns wraps notRead; without a terminal, the error says to set
+// envVar instead.
+func readFromTerminal(
+	prompt string, notRead error, envVar string,
+) (*memguard.LockedBuffer, error) {
 	// Check if stdin is a terminal
 	if !term.IsTerminal(syscall.Stdin) {
-		// Not a terminal - never read passphrases from piped input
+		// Not a terminal - never read secrets from piped input
 		// for security reasons
-		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errStdinNotTerminal)
+		return nil, fmt.Errorf(
+			"%w: %w. Please set the %s environment variable or run interactively",
+			notRead, errStdinNotTerminal, envVar)
 	}
 
 	// stdin is a terminal, check if stderr is also a terminal for
 	// interactive prompting
 	if !term.IsTerminal(syscall.Stderr) {
-		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errStderrNotTerminal)
+		return nil, fmt.Errorf("%w: %w. Please set the %s environment variable",
+			notRead, errStderrNotTerminal, envVar)
 	}
 
 	// Both stdin and stderr are terminals - use secure password reading
 	fmt.Fprint(os.Stderr, prompt) // Write prompt to stderr, not stdout
 
-	passphrase, err := term.ReadPassword(syscall.Stdin)
+	input, err := term.ReadPassword(syscall.Stdin)
 	if err != nil {
-		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, err)
+		return nil, fmt.Errorf("%w: %w", notRead, err)
 	}
 
 	// Print newline to stderr since ReadPassword doesn't echo
 	fmt.Fprintln(os.Stderr)
 
-	if len(passphrase) == 0 {
-		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errEmptyPassphrase)
+	if len(input) == 0 {
+		return nil, fmt.Errorf("%w: %w", notRead, errNothingEntered)
 	}
 
-	// Create a secure buffer and copy the passphrase
-	secureBuffer := memguard.NewBufferFromBytes(passphrase)
+	// Create a secure buffer and copy the input
+	secureBuffer := memguard.NewBufferFromBytes(input)
 
-	// Clear the original passphrase slice
-	for i := range passphrase {
-		passphrase[i] = 0
+	// Clear the original input slice
+	for i := range input {
+		input[i] = 0
 	}
 
 	return secureBuffer, nil