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

`secret rm ..` resolved to the vault directory and 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
without checking it; import checked it only after reading the source
file.

vault.ValidateSecretName wraps the existing name rule and its error
states the rule. Each of those commands calls it on the name as given,
before building any path; a move checks both names before switching
the current vault. AddSecret, GetSecretVersion and GetSecretObject use
it too.

The regression test copies two in-memory vaults for each rejected
command and requires the exact error and an unchanged state directory.

Model: opus-5-5

internal/cli/path_traversal_test.go

@@ -0,0 +1,232 @@
+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)
+		}},
+		// "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)
+		})
+	}
+}