Reject invalid secret names before any command builds a path (closes #33)

`secret rm ..` deleted the whole vault; `secret rm .` and `secret rm ""`
deleted every secret. rm, mv, the version commands, encrypt and decrypt
built paths from the name unchecked; import checked it only after
reading the source file.

Each now calls vault.ValidateSecretName, which wraps the existing rule,
on the name as given, before building any path; MoveSecret checks both
names before switching the current vault. Its error and README.md state
the rule. The test-only copy of the rule in internal/secret is removed.

The regression test runs each rejected command on a copy of two
in-memory vaults and requires the exact error and an unchanged state
directory.

Model: opus-5-5

README.md

@@ -113,7 +113,9 @@ automatically switch to another vault if removing the current one.
 Adds a secret to the current vault. Reads the secret value from stdin.
 - `--force, -f`: Overwrite existing secret
 
-**Secret Name Format:** `[a-z0-9\.\-\_\/]+`
+**Secret Name Format:** only ASCII letters, digits, `.`, `-`, `_` and `/`
+are allowed, and a name must not be empty, start with `.` or `/`, end with
+`/`, contain `//`, or have `..` as a path segment.
 - Forward slashes (`/`) are converted to percent signs (`%`) for storage
 - Examples: `database/password`, `api.key`, `ssh_private_key`
 

TODO.md

@@ -25,6 +25,18 @@ Bring the repo into policy compliance in one commit:
 
 # Completed Steps
 
+- 2026-10-03: Every command that builds a path from a secret name
+  checks the name first with `vault.ValidateSecretName` and touches
+  nothing when it is invalid: `rm`, `mv` (both names, within a vault
+  and between vaults, before switching the current vault), `import`,
+  `version list`/`promote`/`rm`, `encrypt` and `decrypt`. The error
+  and `README.md` state the naming rule. Before, `secret rm ..`
+  deleted the whole vault and `secret rm .` every secret in it.
+- 2026-10-03: The keychain unlocker's age key passphrase stays in
+  locked memory: it is generated into a locked buffer, and the
+  keychain JSON is written and read by `KeychainData` code in
+  `internal/secret/keychaindata.go` (tested on Linux) without
+  `encoding/json` holding it; the JSON field names are unchanged.
 - 2026-10-02: A plain `docker build .` builds again: the size tests
   skip a case that needs more locked memory than the process can
   lock, and run every case under `script/cibuild`. The image stamps the
@@ -88,16 +100,14 @@ Bring the repo into policy compliance in one commit:
     - Command injection: GPG key IDs passed unescaped to exec.Command
       (pgpunlocker.go:323-327); data.String() passed unescaped to the
       security command (keychainunlocker.go:472-476).
-    - Memory security: KeychainData stores AgePrivKeyPassphrase as a
-      plain string (keychainunlocker.go:342,393-396); age identity
-      .String() creates unprotected copies (keychainunlocker.go:356,
-      pgpunlocker.go:256, version.go:155); age secret key held in a
-      plain string in cli/crypto.go:86,91,113; private keys exposed via
-      buffer.Bytes() to GPGEncryptFunc and EncryptWithPassphrase.
+    - Memory security: age identity .String() creates unprotected
+      copies (keychainunlocker.go:356, pgpunlocker.go:256,
+      version.go:155); age secret key held in a plain string in
+      cli/crypto.go:86,91,113; private keys exposed via buffer.Bytes()
+      to GPGEncryptFunc and EncryptWithPassphrase.
     - Race conditions: no file locking in vault/secrets.go:142-176;
       non-atomic writes can leave the vault inconsistent.
-    - Input validation: dots in secret names risk path traversal
-      (vault/secrets.go:75-99); no maximum secret size (DoS).
+    - Input validation: no maximum secret size (DoS).
     - Timing attacks: bytes.Equal passphrase compare (cli/init.go:
       209-216); non-constant-time public key compare (vault.go:95-100).
 - High priority:

internal/cli/crypto.go

@@ -122,6 +122,11 @@ func (cli *Instance) resolveEncryptionKey(
 
 // Encrypt encrypts data using an age secret key stored in a secret
 func (cli *Instance) Encrypt(secretName, inputFile, outputFile string) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {
@@ -191,6 +196,11 @@ func (cli *Instance) Encrypt(secretName, inputFile, outputFile string) error {
 
 // Decrypt decrypts data using an age secret key stored in a secret
 func (cli *Instance) Decrypt(secretName, inputFile, outputFile string) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {

internal/cli/path_traversal_test.go

@@ -0,0 +1,267 @@
+package cli_test
+
+import (
+	"maps"
+	"os"
+	"slices"
+	"strings"
+	"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"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	// testStateDir is the in-memory state directory of the test vaults.
+	testStateDir = "/test/state"
+
+	// testPassphrase protects the passphrase unlocker of each test vault.
+	testPassphrase = "test-passphrase"
+
+	// testVersion is a version name in the format the vault uses.
+	testVersion = "20260101.001"
+
+	// missingFile is an import source that does not exist, so an import
+	// that opened it before checking the name would fail with another error.
+	missingFile = "/no/such/file"
+)
+
+// newTwoVaultFs returns an in-memory filesystem holding the vaults "work"
+// and "default", the current one. Each holds the secret "x" and a
+// passphrase unlocker, so both secrets.d and unlockers.d have contents.
+//
+//nolint:ireturn // afero.Fs is the filesystem abstraction used throughout
+func newTwoVaultFs(t *testing.T) afero.Fs {
+	t.Helper()
+
+	t.Setenv(secret.EnvMnemonic, testMnemonic)
+
+	fs := afero.NewMemMapFs()
+
+	for _, name := range []string{"work", "default"} {
+		vlt, err := vault.CreateVault(fs, testStateDir, name)
+		require.NoError(t, err)
+
+		err = vlt.AddSecret("x", memguard.NewBufferFromBytes([]byte("value")), false)
+		require.NoError(t, err)
+
+		_, err = vlt.CreatePassphraseUnlocker(
+			memguard.NewBufferFromBytes([]byte(testPassphrase)))
+		require.NoError(t, err)
+	}
+
+	return fs
+}
+
+// snapshotStateDir maps every file under the state directory to its
+// contents, and every directory, written with a trailing "/", to "". Two
+// snapshots are equal only if nothing in it was added, removed or changed.
+func snapshotStateDir(t *testing.T, fs afero.Fs) map[string]string {
+	t.Helper()
+
+	tree := map[string]string{}
+
+	err := afero.Walk(fs, testStateDir, func(
+		path string, info os.FileInfo, err error,
+	) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			tree[path+"/"] = ""
+
+			return nil
+		}
+
+		content, err := afero.ReadFile(fs, path)
+		if err != nil {
+			return err
+		}
+
+		tree[path] = string(content)
+
+		return nil
+	})
+	require.NoError(t, err)
+
+	return tree
+}
+
+// newFsFromSnapshot returns a new in-memory filesystem holding exactly the
+// directories and files recorded by snapshotStateDir.
+//
+//nolint:ireturn // afero.Fs is the filesystem abstraction used throughout
+func newFsFromSnapshot(t *testing.T, tree map[string]string) afero.Fs {
+	t.Helper()
+
+	fs := afero.NewMemMapFs()
+
+	// In sorted order every directory comes before its contents.
+	for _, path := range slices.Sorted(maps.Keys(tree)) {
+		dir, isDir := strings.CutSuffix(path, "/")
+		if isDir {
+			require.NoError(t, fs.MkdirAll(dir, secret.DirPerms))
+
+			continue
+		}
+
+		err := afero.WriteFile(fs, path, []byte(tree[path]), secret.FilePerms)
+		require.NoError(t, err)
+	}
+
+	return fs
+}
+
+// requireRejectedAndUnchanged runs a command on a copy of the state
+// directory recorded in before. It requires exactly the error
+// vault.ValidateSecretName gives for the rejected name, so that a later
+// check rejecting the name does not count, and everything under the state
+// directory as it was: the error alone proves nothing, since it could come
+// after the vault had already been deleted.
+func requireRejectedAndUnchanged(
+	t *testing.T, before map[string]string, rejected string,
+	run func(c *cli.Instance) error,
+) {
+	t.Helper()
+
+	fs := newFsFromSnapshot(t, before)
+
+	err := run(cli.NewCLIInstanceWithStateDir(fs, testStateDir))
+
+	require.Equal(t, before, snapshotStateDir(t, fs))
+	require.ErrorIs(t, err, vault.ErrInvalidSecretName)
+	require.EqualError(t, err, vault.ValidateSecretName(rejected).Error())
+}
+
+// TestInvalidSecretNameLeavesVaultsUnchanged is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/33, where `secret rm ..` deleted
+// the whole vault, and `secret rm .` or `secret rm ""` every secret in it.
+// Moves and imports use --force, so that only the name check stands in
+// the way.
+//
+//nolint:paralleltest // newTwoVaultFs uses t.Setenv
+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.
+	before := snapshotStateDir(t, newTwoVaultFs(t))
+
+	vaultDir := testStateDir + "/vaults.d/default"
+	require.Contains(t, before, vaultDir+"/secrets.d/x/")
+	require.Contains(t, before, vaultDir+"/unlockers.d/passphrase/")
+	require.Equal(t, "default", before[testStateDir+"/currentvault"])
+
+	cmd := &cobra.Command{}
+
+	tests := []struct {
+		command  string
+		rejected string // the secret name the command must reject
+		run      func(c *cli.Instance) error
+	}{
+		{"rm ..", "..", func(c *cli.Instance) error {
+			return c.RemoveSecret(cmd, "..", false)
+		}},
+		{"rm .", ".", func(c *cli.Instance) error {
+			return c.RemoveSecret(cmd, ".", false)
+		}},
+		{`rm ""`, "", func(c *cli.Instance) error {
+			return c.RemoveSecret(cmd, "", false)
+		}},
+		{"rm ../../etc", "../../etc", func(c *cli.Instance) error {
+			return c.RemoveSecret(cmd, "../../etc", false)
+		}},
+		{"mv --force .. x", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "..", "x", true)
+		}},
+		{"mv --force x ..", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "x", "..", true)
+		}},
+		{`mv --force x ""`, "", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "x", "", true)
+		}},
+		// "work" is not the current vault: a move within it must not
+		// select it when a name is rejected.
+		{"mv --force work:.. work:x", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "work:..", "work:x", true)
+		}},
+		{"mv --force work:x work:..", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "work:x", "work:..", true)
+		}},
+		{"mv --force default:.. work", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "default:..", "work", true)
+		}},
+		{"mv --force default:.. work:y", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "default:..", "work:y", true)
+		}},
+		{"mv --force default:x work:..", "..", func(c *cli.Instance) error {
+			return c.MoveSecret(cmd, "default:x", "work:..", true)
+		}},
+		{"import --force ..", "..", func(c *cli.Instance) error {
+			return c.ImportSecret(cmd, "..", missingFile, true)
+		}},
+		{"import --force .", ".", func(c *cli.Instance) error {
+			return c.ImportSecret(cmd, ".", missingFile, true)
+		}},
+		{"import --force ../../etc", "../../etc", func(c *cli.Instance) error {
+			return c.ImportSecret(cmd, "../../etc", missingFile, true)
+		}},
+		{"version list ..", "..", func(c *cli.Instance) error {
+			return c.ListVersions(cmd, "..")
+		}},
+		{"version promote ..", "..", func(c *cli.Instance) error {
+			return c.PromoteVersion(cmd, "..", testVersion)
+		}},
+		{"version rm ..", "..", func(c *cli.Instance) error {
+			return c.RemoveVersion(cmd, "..", testVersion)
+		}},
+		{"encrypt ..", "..", func(c *cli.Instance) error {
+			return c.Encrypt("..", "", "")
+		}},
+		{"decrypt ..", "..", func(c *cli.Instance) error {
+			return c.Decrypt("..", "", "")
+		}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.command, func(t *testing.T) {
+			requireRejectedAndUnchanged(t, before, tt.rejected, tt.run)
+		})
+	}
+}
+
+// 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) {
+	before := snapshotStateDir(t, newTwoVaultFs(t))
+	fs := newFsFromSnapshot(t, before)
+
+	c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
+	err := c.MoveSecret(&cobra.Command{}, "x", "work", false)
+	require.NoError(t, err)
+
+	// Expected: the state as before, with everything under the current
+	// vault's secrets.d/x/ now under secrets.d/work/.
+	oldDir := testStateDir + "/vaults.d/default/secrets.d/x/"
+	newDir := testStateDir + "/vaults.d/default/secrets.d/work/"
+	want := map[string]string{}
+
+	for path, content := range before {
+		rest, found := strings.CutPrefix(path, oldDir)
+		if found {
+			path = newDir + rest
+		}
+
+		want[path] = content
+	}
+
+	require.Contains(t, want, newDir)
+	require.Equal(t, want, snapshotStateDir(t, fs))
+}

internal/cli/secrets.go

@@ -603,6 +603,11 @@ func printSecretsTable(
 func (cli *Instance) ImportSecret(
 	cmd *cobra.Command, secretName, sourceFile string, force bool,
 ) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {
@@ -649,6 +654,11 @@ func (cli *Instance) ImportSecret(
 
 // RemoveSecret removes a secret from the vault
 func (cli *Instance) RemoveSecret(cmd *cobra.Command, secretName string, _ bool) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	currentVlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {
@@ -702,13 +712,8 @@ func (cli *Instance) MoveSecret(
 	srcVaultName, srcSecretName, srcQualified := ParseVaultSecretRef(source)
 	destVaultName, destSecretName, destQualified := ParseVaultSecretRef(dest)
 
-	// If neither is qualified, this is a simple within-vault rename
-	if !srcQualified && !destQualified {
-		return cli.moveSecretWithinVault(cmd, srcSecretName, destSecretName, force)
-	}
-
 	// Cross-vault move requires source to be qualified
-	if !srcQualified {
+	if !srcQualified && destQualified {
 		return errCrossVaultSourceUnqualified
 	}
 
@@ -716,31 +721,46 @@ func (cli *Instance) MoveSecret(
 	// Format: "work:secret default" means move to vault "default"
 	// Format: "work:secret default:newname" means move to vault "default"
 	// with a new name
-	if !destQualified {
+	if srcQualified && !destQualified {
 		// Check if dest is actually a vault name
 		vaults, err := vault.ListVaults(cli.fs, cli.stateDir)
 		if err == nil && slices.Contains(vaults, dest) {
 			// dest is a vault name, use source secret name
 			destVaultName = dest
 			destSecretName = srcSecretName
-		}
-
-		// If destVaultName is still empty, dest is a secret name in source vault
-		if destVaultName == "" {
+		} else {
+			// dest is a secret name in source vault
 			destVaultName = srcVaultName
-			destSecretName = dest
 		}
 	}
 
-	// If destination secret name is empty, use source secret name
-	if destSecretName == "" {
+	// If destination secret name is empty, use source secret name. A plain
+	// rename keeps it empty, so that the check below rejects it.
+	if srcQualified && destSecretName == "" {
 		destSecretName = srcSecretName
 	}
 
+	// Check both names, for every form of the move, before selecting a vault
+	// below, so that a rejected move leaves the current vault as it was.
+	err := vault.ValidateSecretName(srcSecretName)
+	if err != nil {
+		return err
+	}
+
+	err = vault.ValidateSecretName(destSecretName)
+	if err != nil {
+		return err
+	}
+
+	// If neither is qualified, this is a simple within-vault rename
+	if !srcQualified && !destQualified {
+		return cli.moveSecretWithinVault(cmd, srcSecretName, destSecretName, force)
+	}
+
 	// Same vault? Use simple rename if possible (optimization)
 	if srcVaultName == destVaultName {
 		// Select the vault and do a simple move
-		err := vault.SelectVault(cli.fs, cli.stateDir, srcVaultName)
+		err = vault.SelectVault(cli.fs, cli.stateDir, srcVaultName)
 		if err != nil {
 			return fmt.Errorf("failed to select vault '%s': %w", srcVaultName, err)
 		}
@@ -753,7 +773,8 @@ func (cli *Instance) MoveSecret(
 		cmd, srcVaultName, srcSecretName, destVaultName, destSecretName, force)
 }
 
-// moveSecretWithinVault handles rename within the current vault
+// moveSecretWithinVault handles rename within the current vault. Its caller,
+// MoveSecret, has already checked both secret names.
 func (cli *Instance) moveSecretWithinVault(
 	cmd *cobra.Command, source, dest string, force bool,
 ) error {
@@ -808,7 +829,8 @@ func (cli *Instance) moveSecretWithinVault(
 	return nil
 }
 
-// moveSecretCrossVault handles moving between different vaults
+// moveSecretCrossVault handles moving between different vaults. Its caller,
+// MoveSecret, has already checked both secret names.
 func (cli *Instance) moveSecretCrossVault(
 	cmd *cobra.Command,
 	srcVaultName, srcSecretName,

internal/cli/version.go

@@ -112,6 +112,11 @@ func VersionCommands(cli *Instance) *cobra.Command {
 func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 	secret.Debug("ListVersions called", "secret_name", secretName)
 
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {
@@ -239,6 +244,11 @@ func formatVersionTime(t *time.Time) string {
 func (cli *Instance) PromoteVersion(
 	cmd *cobra.Command, secretName string, version string,
 ) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {
@@ -282,6 +292,11 @@ func (cli *Instance) PromoteVersion(
 func (cli *Instance) RemoveVersion(
 	cmd *cobra.Command, secretName string, version string,
 ) error {
+	err := vault.ValidateSecretName(secretName)
+	if err != nil {
+		return err
+	}
+
 	// Get current vault
 	vlt, err := vault.GetCurrentVault(cli.fs, cli.stateDir)
 	if err != nil {

internal/secret/helpers_darwin.go

@@ -1,29 +0,0 @@
-//go:build darwin
-
-package secret
-
-import (
-	"crypto/rand"
-	"fmt"
-	"math/big"
-)
-
-// generateRandomString generates a random string of the specified length using the given character set
-func generateRandomString(length int, charset string) (string, error) {
-	if length <= 0 {
-		return "", fmt.Errorf("length must be positive")
-	}
-
-	result := make([]byte, length)
-	charsetLen := big.NewInt(int64(len(charset)))
-
-	for i := range length {
-		randomIndex, err := rand.Int(rand.Reader, charsetLen)
-		if err != nil {
-			return "", fmt.Errorf("failed to generate random number: %w", err)
-		}
-		result[i] = charset[randomIndex.Int64()]
-	}
-
-	return string(result), nil
-}

internal/secret/keychaindata.go

@@ -0,0 +1,142 @@
+package secret
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/awnumar/memguard"
+)
+
+var (
+	errPassphraseLength = errors.New(
+		"passphrase length must be a positive even number")
+	errPassphraseNotHex = errors.New(
+		"keychain passphrase must be lowercase hex")
+	errNoKeychainPassphrase = errors.New(
+		"keychain data has no agePrivKeyPassphrase string")
+)
+
+// KeychainData is what a keychain unlocker stores in the macOS keychain.
+// It is stored as JSON, but encode and decodeKeychainData keep the
+// passphrase out of encoding/json, which would leave copies of it in
+// ordinary memory.
+type KeychainData struct {
+	AgePublicKey         string
+	AgePrivKeyPassphrase *memguard.LockedBuffer
+	EncryptedLongtermKey string
+}
+
+// generateRandomPassphrase returns length random lowercase hex characters
+// in a locked buffer. The caller must destroy it.
+func generateRandomPassphrase(length int) (*memguard.LockedBuffer, error) {
+	// Each random byte becomes two hex characters.
+	randomBytes := hex.DecodedLen(length)
+	if length <= 0 || hex.EncodedLen(randomBytes) != length {
+		return nil, errPassphraseLength
+	}
+
+	random := memguard.NewBufferRandom(randomBytes)
+	defer random.Destroy()
+
+	passphrase := memguard.NewBuffer(length)
+	hex.Encode(passphrase.Bytes(), random.Bytes())
+	passphrase.Freeze()
+
+	return passphrase, nil
+}
+
+// encode returns d as JSON in a locked buffer:
+// {"agePublicKey":"...","agePrivKeyPassphrase":"...","encryptedLongtermKey":"..."}.
+// The passphrase is copied straight into the buffer, so it must be hex,
+// which JSON does not escape. The caller must destroy the returned buffer.
+func (d *KeychainData) encode() (*memguard.LockedBuffer, error) {
+	if d.AgePrivKeyPassphrase == nil {
+		return nil, errNilPassphraseBuffer
+	}
+
+	if d.AgePrivKeyPassphrase.Size() == 0 {
+		return nil, errEmptyPassphrase
+	}
+
+	for _, c := range d.AgePrivKeyPassphrase.Bytes() {
+		if strings.IndexByte("0123456789abcdef", c) < 0 {
+			return nil, errPassphraseNotHex
+		}
+	}
+
+	publicKey, err := json.Marshal(d.AgePublicKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode age public key: %w", err)
+	}
+
+	longtermKey, err := json.Marshal(d.EncryptedLongtermKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode long-term key: %w", err)
+	}
+
+	parts := [][]byte{
+		[]byte(`{"agePublicKey":`), publicKey,
+		[]byte(`,"agePrivKeyPassphrase":"`), d.AgePrivKeyPassphrase.Bytes(),
+		[]byte(`","encryptedLongtermKey":`), longtermKey,
+		[]byte(`}`),
+	}
+
+	size := 0
+	for _, part := range parts {
+		size += len(part)
+	}
+
+	encoded := memguard.NewBuffer(size)
+
+	written := 0
+	for _, part := range parts {
+		written += copy(encoded.Bytes()[written:], part)
+	}
+
+	encoded.Freeze()
+
+	return encoded, nil
+}
+
+// decodeKeychainData parses keychain data written by encode. The caller
+// must destroy the returned AgePrivKeyPassphrase.
+func decodeKeychainData(data *memguard.LockedBuffer) (*KeychainData, error) {
+	if data == nil {
+		return nil, errNilDataBuffer
+	}
+
+	// json.Unmarshal gives a json.RawMessage field the field's JSON text
+	// unchanged, in the one copy RawMessage makes; it is wiped on return.
+	var fields struct {
+		AgePublicKey         string          `json:"agePublicKey"`
+		AgePrivKeyPassphrase json.RawMessage `json:"agePrivKeyPassphrase"`
+		EncryptedLongtermKey string          `json:"encryptedLongtermKey"`
+	}
+
+	defer func() { memguard.WipeBytes(fields.AgePrivKeyPassphrase) }()
+
+	err := json.Unmarshal(data.Bytes(), &fields)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse keychain data: %w", err)
+	}
+
+	// json.Unmarshal accepted the JSON, so text that starts with a quote is
+	// a whole string. The passphrase is hex, so it is the text between the
+	// quotes.
+	quoted := fields.AgePrivKeyPassphrase
+	if !bytes.HasPrefix(quoted, []byte(`"`)) {
+		return nil, errNoKeychainPassphrase
+	}
+
+	return &KeychainData{
+		AgePublicKey: fields.AgePublicKey,
+		// NewBufferFromBytes wipes the bytes it copies.
+		AgePrivKeyPassphrase: memguard.NewBufferFromBytes(
+			quoted[1 : len(quoted)-1]),
+		EncryptedLongtermKey: fields.EncryptedLongtermKey,
+	}, nil
+}

internal/secret/keychaindata_test.go

@@ -0,0 +1,118 @@
+//nolint:testpackage // white-box test of unexported internals
+package secret
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/awnumar/memguard"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGenerateRandomPassphrase(t *testing.T) {
+	t.Parallel()
+
+	first, err := generateRandomPassphrase(64)
+	require.NoError(t, err)
+
+	defer first.Destroy()
+
+	second, err := generateRandomPassphrase(64)
+	require.NoError(t, err)
+
+	defer second.Destroy()
+
+	assert.Regexp(t, `^[0-9a-f]{64}$`, first.String())
+	assert.NotEqual(t, first.String(), second.String())
+	assert.False(t, first.IsMutable())
+
+	for _, length := range []int{0, -2, 63} {
+		_, err := generateRandomPassphrase(length)
+		require.ErrorIs(t, err, errPassphraseLength, "length %d", length)
+	}
+}
+
+func TestKeychainDataEncodeDecode(t *testing.T) {
+	t.Parallel()
+
+	passphrase := memguard.NewBufferFromBytes([]byte("0a1b2c3d"))
+	defer passphrase.Destroy()
+
+	data := KeychainData{
+		AgePublicKey:         "age1example",
+		AgePrivKeyPassphrase: passphrase,
+		EncryptedLongtermKey: "beef",
+	}
+
+	encoded, err := data.encode()
+	require.NoError(t, err)
+
+	defer encoded.Destroy()
+
+	assert.JSONEq(t,
+		`{"agePublicKey":"age1example",`+
+			`"agePrivKeyPassphrase":"0a1b2c3d",`+
+			`"encryptedLongtermKey":"beef"}`,
+		encoded.String())
+	assert.False(t, encoded.IsMutable())
+
+	decoded, err := decodeKeychainData(encoded)
+	require.NoError(t, err)
+
+	defer decoded.AgePrivKeyPassphrase.Destroy()
+
+	assert.Equal(t, "age1example", decoded.AgePublicKey)
+	assert.Equal(t, "0a1b2c3d", decoded.AgePrivKeyPassphrase.String())
+	assert.Equal(t, "beef", decoded.EncryptedLongtermKey)
+}
+
+func TestKeychainDataEncodeRejectsBadPassphrase(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		passphrase *memguard.LockedBuffer
+		wantErr    error
+	}{
+		{"nil", nil, errNilPassphraseBuffer},
+		{"empty", memguard.NewBuffer(0), errEmptyPassphrase},
+		{
+			"not hex",
+			memguard.NewBufferFromBytes([]byte(`abc"def`)),
+			errPassphraseNotHex,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			data := KeychainData{AgePrivKeyPassphrase: tt.passphrase}
+			_, err := data.encode()
+			require.ErrorIs(t, err, tt.wantErr)
+		})
+	}
+}
+
+func TestDecodeKeychainDataRejectsBadData(t *testing.T) {
+	t.Parallel()
+
+	for _, text := range []string{
+		`{"agePublicKey":"age1example"}`,
+		`{"agePrivKeyPassphrase":42}`,
+	} {
+		data := memguard.NewBufferFromBytes([]byte(text))
+		_, err := decodeKeychainData(data)
+		data.Destroy()
+		require.ErrorIs(t, err, errNoKeychainPassphrase, text)
+	}
+
+	notJSON := memguard.NewBufferFromBytes([]byte(`{"agePrivKeyPassphrase":`))
+	defer notJSON.Destroy()
+
+	_, err := decodeKeychainData(notJSON)
+
+	var syntaxError *json.SyntaxError
+	require.ErrorAs(t, err, &syntaxError)
+}

internal/secret/keychainunlocker.go

@@ -45,13 +45,6 @@ type KeychainUnlocker struct {
 	fs        afero.Fs
 }
 
-// KeychainData represents the data stored in the macOS keychain
-type KeychainData struct {
-	AgePublicKey         string `json:"agePublicKey"`
-	AgePrivKeyPassphrase string `json:"agePrivKeyPassphrase"`
-	EncryptedLongtermKey string `json:"encryptedLongtermKey"`
-}
-
 // GetIdentity implements Unlocker interface for Keychain-based unlockers
 func (k *KeychainUnlocker) GetIdentity() (*age.X25519Identity, error) {
 	DebugWith("Getting keychain unlocker identity",
@@ -81,13 +74,18 @@ func (k *KeychainUnlocker) GetIdentity() (*age.X25519Identity, error) {
 		slog.Int("data_length", len(keychainDataBytes)),
 	)
 
+	// Move the keychain data into locked memory; this wipes keychainDataBytes
+	keychainDataBuffer := memguard.NewBufferFromBytes(keychainDataBytes)
+	defer keychainDataBuffer.Destroy()
+
 	// Step 3: Parse keychain data
-	var keychainData KeychainData
-	if err := json.Unmarshal(keychainDataBytes, &keychainData); err != nil {
+	keychainData, err := decodeKeychainData(keychainDataBuffer)
+	if err != nil {
 		Debug("Failed to parse keychain data", "error", err, "unlocker_id", k.GetID())
 
 		return nil, fmt.Errorf("failed to parse keychain data: %w", err)
 	}
+	defer keychainData.AgePrivKeyPassphrase.Destroy()
 
 	Debug("Parsed keychain data successfully", "unlocker_id", k.GetID())
 
@@ -109,11 +107,7 @@ func (k *KeychainUnlocker) GetIdentity() (*age.X25519Identity, error) {
 
 	// Step 5: Decrypt the age private key using the passphrase from keychain
 	Debug("Decrypting age private key with keychain passphrase", "unlocker_id", k.GetID())
-	// Create secure buffer for the keychain passphrase
-	passphraseBuffer := memguard.NewBufferFromBytes([]byte(keychainData.AgePrivKeyPassphrase))
-	defer passphraseBuffer.Destroy()
-
-	agePrivKeyBuffer, err := DecryptWithPassphrase(encryptedAgePrivKeyData, passphraseBuffer)
+	agePrivKeyBuffer, err := DecryptWithPassphrase(encryptedAgePrivKeyData, keychainData.AgePrivKeyPassphrase)
 	if err != nil {
 		Debug("Failed to decrypt age private key with keychain passphrase", "error", err, "unlocker_id", k.GetID())
 
@@ -369,6 +363,7 @@ func CreateKeychainUnlocker(fs afero.Fs, stateDir string) (*KeychainUnlocker, er
 	if err != nil {
 		return nil, fmt.Errorf("failed to generate age private key passphrase: %w", err)
 	}
+	defer agePrivKeyPassphrase.Destroy()
 
 	// Step 3: Store age recipient as plaintext
 	ageRecipient := ageIdentity.Recipient().String()
@@ -378,15 +373,12 @@ func CreateKeychainUnlocker(fs afero.Fs, stateDir string) (*KeychainUnlocker, er
 	}
 
 	// Step 4: Encrypt age private key with the generated passphrase and store on disk
-	// Create secure buffers for both the private key and passphrase
+	// Create a secure buffer for the private key
 	agePrivKeyStr := ageIdentity.String()
 	agePrivKeyBuffer := memguard.NewBufferFromBytes([]byte(agePrivKeyStr))
 	defer agePrivKeyBuffer.Destroy()
 
-	passphraseBuffer := memguard.NewBufferFromBytes([]byte(agePrivKeyPassphrase))
-	defer passphraseBuffer.Destroy()
-
-	encryptedAgePrivKey, err := EncryptWithPassphrase(agePrivKeyBuffer, passphraseBuffer)
+	encryptedAgePrivKey, err := EncryptWithPassphrase(agePrivKeyBuffer, agePrivKeyPassphrase)
 	if err != nil {
 		return nil, fmt.Errorf("failed to encrypt age private key with passphrase: %w", err)
 	}
@@ -422,13 +414,10 @@ func CreateKeychainUnlocker(fs afero.Fs, stateDir string) (*KeychainUnlocker, er
 		EncryptedLongtermKey: hex.EncodeToString(encryptedLtPrivKeyToAge),
 	}
 
-	keychainDataBytes, err := json.Marshal(keychainData)
+	keychainDataBuffer, err := keychainData.encode()
 	if err != nil {
-		return nil, fmt.Errorf("failed to marshal keychain data: %w", err)
+		return nil, fmt.Errorf("failed to encode keychain data: %w", err)
 	}
-
-	// Create a secure buffer for keychain data
-	keychainDataBuffer := memguard.NewBufferFromBytes(keychainDataBytes)
 	defer keychainDataBuffer.Destroy()
 
 	// Step 8: Store data in keychain
@@ -501,7 +490,7 @@ func storeInKeychain(itemName string, data *memguard.LockedBuffer) error {
 	item.SetAccount(itemName)
 	item.SetLabel(fmt.Sprintf("%s - %s", KEYCHAIN_APP_IDENTIFIER, itemName))
 	item.SetDescription("Secret vault keychain data")
-	item.SetData([]byte(data.String()))
+	item.SetData(data.Bytes())
 	item.SetSynchronizable(keychain.SynchronizableNo)
 	// Use AccessibleWhenUnlockedThisDeviceOnly for better security and to trigger auth
 	item.SetAccessible(keychain.AccessibleWhenUnlockedThisDeviceOnly)
@@ -576,8 +565,3 @@ func deleteFromKeychain(itemName string) error {
 
 	return nil
 }
-
-// generateRandomPassphrase generates a random passphrase for encrypting the age private key
-func generateRandomPassphrase(length int) (string, error) {
-	return generateRandomString(length, "0123456789abcdef")
-}

internal/secret/secret_test.go

@@ -310,64 +310,6 @@ func TestPerSecretKeyFunctionality(t *testing.T) {
 	})
 }
 
-// For testing purposes only
-func isValidSecretName(name string) bool {
-	if name == "" {
-		return false
-	}
-	// Valid characters for secret names: letters, numbers, dash, dot, underscore, slash
-	for _, char := range name {
-		if (char < 'a' || char > 'z') && // lowercase letters
-			(char < 'A' || char > 'Z') && // uppercase letters
-			(char < '0' || char > '9') && // numbers
-			char != '-' && // dash
-			char != '.' && // dot
-			char != '_' && // underscore
-			char != '/' { // slash
-			return false
-		}
-	}
-
-	return true
-}
-
-func TestSecretNameValidation(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name  string
-		valid bool
-	}{
-		{"valid-name", true},
-		{"valid.name", true},
-		{"valid_name", true},
-		{"valid/path/name", true},
-		{"123valid", true},
-		{"", false},
-		{"Valid-Upper-Name", true}, // uppercase allowed
-		{"2025-11-21-ber1app1-vaultik-test-bucket-AKI", true}, // real-world uppercase key ID
-		{"MixedCase/Path/Name", true},                         // mixed case with path
-		{"invalid name", false},                               // space not allowed
-		{"invalid@name", false},                               // @ not allowed
-	}
-
-	for _, test := range tests {
-		t.Run(test.name, func(t *testing.T) {
-			t.Parallel()
-
-			result := isValidSecretName(test.name)
-			if result != test.valid {
-				t.Errorf(
-					"isValidSecretName(%q) = %v, want %v",
-					test.name,
-					result,
-					test.valid,
-				)
-			}
-		})
-	}
-}
-
 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

internal/vault/errors.go

@@ -29,10 +29,11 @@ var (
 	// ErrNilValueBuffer indicates a nil value buffer was supplied.
 	ErrNilValueBuffer = errors.New("value buffer is nil")
 
-	// ErrInvalidSecretName indicates a secret name that does not match
-	// the allowed pattern [a-z0-9.\-_/]+. Composed as
-	// "invalid secret name '<name>': must match pattern [a-z0-9.\-_/]+",
-	// or as "invalid secret name: <name>" by GetSecretObject.
+	// ErrInvalidSecretName indicates a secret name that breaks the naming
+	// rule: only ASCII letters, digits, '.', '-', '_' and '/'; not empty;
+	// no leading '.' or '/', no trailing '/', no '//', no '..' path segment.
+	// Composed by ValidateSecretName as
+	// "invalid secret name '<name>': <the rule>".
 	ErrInvalidSecretName = errors.New("invalid secret name")
 
 	// ErrSecretExists indicates the secret already exists and --force

internal/vault/secrets.go

@@ -79,6 +79,7 @@ func (v *Vault) ListSecrets() ([]string, error) {
 // - No leading or trailing slashes
 // - No double slashes
 // - No names starting with dots
+// - No ".." path segments
 func isValidSecretName(name string) bool {
 	if name == "" {
 		return false
@@ -110,6 +111,22 @@ func isValidSecretName(name string) bool {
 	return matched
 }
 
+// ValidateSecretName returns an error wrapping ErrInvalidSecretName when
+// name is not a valid secret name. Call it on the name exactly as the user
+// gave it, before building any path from it.
+func ValidateSecretName(name string) error {
+	if !isValidSecretName(name) {
+		return fmt.Errorf(
+			"%w '%s': only ASCII letters, digits, '.', '-', '_' and '/' are allowed, "+
+				"and a name must not be empty, start with '.' or '/', end with '/', "+
+				"contain '//', or have '..' as a path segment",
+			ErrInvalidSecretName, name,
+		)
+	}
+
+	return nil
+}
+
 // AddSecret adds a secret to this vault
 func (v *Vault) AddSecret(name string, value *memguard.LockedBuffer, force bool) error {
 	if value == nil {
@@ -124,13 +141,11 @@ func (v *Vault) AddSecret(name string, value *memguard.LockedBuffer, force bool)
 	)
 
 	// Validate secret name
-	if !isValidSecretName(name) {
+	err := ValidateSecretName(name)
+	if err != nil {
 		secret.Debug("Invalid secret name provided", "secret_name", name)
 
-		return fmt.Errorf(
-			"%w '%s': must match pattern [a-z0-9.\\-_/]+",
-			ErrInvalidSecretName, name,
-		)
+		return err
 	}
 
 	secret.Debug("Secret name validation passed", "secret_name", name)
@@ -358,8 +373,9 @@ func (v *Vault) UnlockVault() (*age.X25519Identity, error) {
 
 // GetSecretObject retrieves a Secret object with metadata loaded from this vault
 func (v *Vault) GetSecretObject(name string) (*secret.Secret, error) {
-	if !isValidSecretName(name) {
-		return nil, fmt.Errorf("%w: %s", ErrInvalidSecretName, name)
+	err := ValidateSecretName(name)
+	if err != nil {
+		return nil, err
 	}
 
 	// First check if the secret exists by checking for the metadata file
@@ -628,13 +644,11 @@ func (v *Vault) updatePreviousVersion(
 // version exist, and resolves an empty version to the current one.
 func (v *Vault) resolveSecretVersion(name, version string) (string, error) {
 	// Validate secret name to prevent path traversal
-	if !isValidSecretName(name) {
+	err := ValidateSecretName(name)
+	if err != nil {
 		secret.Debug("Invalid secret name provided", "secret_name", name)
 
-		return "", fmt.Errorf(
-			"%w '%s': must match pattern [a-z0-9.\\-_/]+",
-			ErrInvalidSecretName, name,
-		)
+		return "", err
 	}
 
 	// Get vault directory