secret/internal/secret/pgpunlock_test.go

//go:build darwin

package secret_test

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"filippo.io/age"
	"github.com/awnumar/memguard"
	"github.com/spf13/afero"
	"sneak.berlin/go/secret/internal/secret"
	"sneak.berlin/go/secret/internal/vault"
	"sneak.berlin/go/secret/pkg/agehd"
)

// pgpUnlockerType is the type of a PGP unlocker.
const pgpUnlockerType = "pgp"

var errNilDataBuffer = errors.New("data buffer is nil")

// setupNonInteractiveGPG creates a custom GPG environment for testing
func setupNonInteractiveGPG(t *testing.T, _, passphrase, gnupgHomeDir string) {
	t.Helper()

	// Create GPG config file for non-interactive operation
	gpgConfPath := filepath.Join(gnupgHomeDir, "gpg.conf")
	gpgConfContent := `batch
no-tty
pinentry-mode loopback
`

	err := os.WriteFile(gpgConfPath, []byte(gpgConfContent), 0o600)
	if err != nil {
		t.Fatalf("Failed to write GPG config file: %v", err)
	}

	// Create a test-specific GPG implementation
	origEncryptFunc := secret.GPGEncryptFunc
	origDecryptFunc := secret.GPGDecryptFunc

	// Set custom GPG functions for this test
	secret.GPGEncryptFunc = func(
		data *memguard.LockedBuffer, keyID string,
	) ([]byte, error) {
		if data == nil {
			return nil, errNilDataBuffer
		}

		//nolint:gosec // G204: test runs gpg with test-controlled arguments
		cmd := exec.CommandContext(t.Context(), "gpg",
			"--homedir", gnupgHomeDir,
			"--batch",
			"--yes",
			"--pinentry-mode", "loopback",
			"--passphrase", passphrase,
			"--trust-model", "always",
			"--armor",
			"--encrypt",
			"-r", keyID)

		var stdout, stderr bytes.Buffer

		cmd.Stdout = &stdout
		cmd.Stderr = &stderr
		cmd.Stdin = bytes.NewReader(data.Bytes())

		err := cmd.Run()
		if err != nil {
			return nil, fmt.Errorf("GPG encryption failed: %w\nStderr: %s", err, stderr.String())
		}

		return stdout.Bytes(), nil
	}

	secret.GPGDecryptFunc = func(encryptedData []byte) (*memguard.LockedBuffer, error) {
		//nolint:gosec // G204: test runs gpg with test-controlled arguments
		cmd := exec.CommandContext(t.Context(), "gpg",
			"--homedir", gnupgHomeDir,
			"--batch",
			"--yes",
			"--pinentry-mode", "loopback",
			"--passphrase", passphrase,
			"--quiet",
			"--decrypt")

		var stdout, stderr bytes.Buffer

		cmd.Stdout = &stdout
		cmd.Stderr = &stderr
		cmd.Stdin = bytes.NewReader(encryptedData)

		err := cmd.Run()
		if err != nil {
			return nil, fmt.Errorf("GPG decryption failed: %w\nStderr: %s", err, stderr.String())
		}

		// Create a secure buffer for the decrypted data
		return memguard.NewBufferFromBytes(stdout.Bytes()), nil
	}

	// Restore original functions after test
	t.Cleanup(func() {
		secret.GPGEncryptFunc = origEncryptFunc
		secret.GPGDecryptFunc = origDecryptFunc
	})
}

// runGPGWithPassphrase executes a GPG command with the specified passphrase
func runGPGWithPassphrase(
	ctx context.Context,
	gnupgHome, passphrase string, args []string, input io.Reader,
) ([]byte, error) {
	cmdArgs := append([]string{
		"--homedir=" + gnupgHome,
		"--batch",
		"--yes",
		"--pinentry-mode", "loopback",
		"--passphrase", passphrase,
	}, args...)

	//nolint:gosec // G204: test runs gpg with test-controlled arguments
	cmd := exec.CommandContext(ctx, "gpg", cmdArgs...)
	cmd.Stdin = input

	var stdout, stderr bytes.Buffer

	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		return nil, fmt.Errorf("GPG command failed: %w\nStderr: %s", err, stderr.String())
	}

	return stdout.Bytes(), nil
}

// generateTestGPGKey generates a GPG key protected by passphrase in
// gnupgHomeDir and returns its key ID and fingerprint.
func generateTestGPGKey(
	t *testing.T, tempDir, gnupgHomeDir, passphrase string,
) (string, string) {
	t.Helper()

	// Create GPG batch file for key generation
	batchFile := filepath.Join(tempDir, "gen-key-batch")
	batchContent := `%echo Generating a test key
Key-Type: RSA
Key-Length: 2048
Name-Real: Test User
Name-Email: test@example.com
Expire-Date: 0
Passphrase: ` + passphrase + `
%commit
%echo Key generation completed
`

	err := os.WriteFile(batchFile, []byte(batchContent), 0o600)
	if err != nil {
		t.Fatalf("Failed to write batch file: %v", err)
	}

	// Generate GPG key with batch mode
	t.Log("Generating GPG key...")

	_, err = runGPGWithPassphrase(t.Context(), gnupgHomeDir, passphrase,
		[]string{"--gen-key", batchFile}, nil)
	if err != nil {
		t.Fatalf("Failed to generate GPG key: %v", err)
	}

	t.Log("GPG key generated successfully")

	// Get the key ID and fingerprint
	output, err := runGPGWithPassphrase(t.Context(), gnupgHomeDir, passphrase,
		[]string{"--list-secret-keys", "--with-colons", "--fingerprint"}, nil)
	if err != nil {
		t.Fatalf("Failed to list GPG keys: %v", err)
	}

	// Parse output to get key ID and fingerprint
	var keyID, fingerprint string

	for line := range strings.SplitSeq(string(output), "\n") {
		if strings.HasPrefix(line, "sec:") {
			fields := strings.Split(line, ":")
			if len(fields) >= 5 {
				keyID = fields[4]
			}
		} else if strings.HasPrefix(line, "fpr:") {
			fields := strings.Split(line, ":")
			if len(fields) >= 10 && fields[9] != "" {
				fingerprint = fields[9]

				break
			}
		}
	}

	if keyID == "" {
		t.Fatalf("Failed to find GPG key ID in output: %s", output)
	}

	if fingerprint == "" {
		t.Fatalf("Failed to find GPG fingerprint in output: %s", output)
	}

	t.Logf("Generated GPG key ID: %s", keyID)
	t.Logf("Generated GPG fingerprint: %s", fingerprint)

	return keyID, fingerprint
}

//nolint:paralleltest // t.Setenv forbids parallel subtests
func TestPGPUnlockerWithRealFS(t *testing.T) {
	// Check if gpg is available
	_, err := exec.LookPath("gpg")
	if err != nil {
		t.Log("GPG not available, PGP unlock key tests may not fully function")
		// Continue anyway to test what we can
	}

	// Create a temporary directory for our tests. Not t.TempDir: its longer
	// path would put gpg-agent's socket in GNUPGHOME past the 104-byte limit
	// macOS sets on socket paths.
	//
	//nolint:usetesting // see the comment above
	tempDir, err := os.MkdirTemp("", "secret-pgp-test-")
	if err != nil {
		t.Fatalf("Failed to create temp dir: %v", err)
	}
	defer func() { _ = os.RemoveAll(tempDir) }() // Clean up after test

	// Create a temporary GNUPGHOME
	gnupgHomeDir := filepath.Join(tempDir, "gnupg")

	err = os.MkdirAll(gnupgHomeDir, 0o700)
	if err != nil {
		t.Fatalf("Failed to create GNUPGHOME: %v", err)
	}

	// Set new GNUPGHOME
	t.Setenv("GNUPGHOME", gnupgHomeDir)

	// Test passphrase for GPG key
	testPassphrase := "test123"

	// Setup non-interactive GPG with custom functions
	setupNonInteractiveGPG(t, tempDir, testPassphrase, gnupgHomeDir)

	keyID, fingerprint := generateTestGPGKey(t, tempDir, gnupgHomeDir, testPassphrase)

	// Set the GPG_AGENT_INFO to empty to ensure gpg-agent doesn't interfere
	t.Setenv("GPG_AGENT_INFO", "")

	// Use the real filesystem
	fs := afero.NewOsFs()

	// Set test environment variables
	t.Setenv(secret.EnvGPGKeyID, keyID)

	// Set up vault structure for testing
	stateDir := tempDir
	vaultName := "test-vault"

	// Test creation of a PGP unlock key through a vault
	t.Run("CreatePGPUnlocker", func(t *testing.T) {
		testCreatePGPUnlocker(t, fs, stateDir, vaultName, keyID, fingerprint)
	})

	// Set up key directory for individual tests
	unlockerDir := filepath.Join(tempDir, "unlocker")

	err = os.MkdirAll(unlockerDir, secret.DirPerms)
	if err != nil {
		t.Fatalf("Failed to create unlocker directory: %v", err)
	}

	// Set up test metadata
	metadata := secret.UnlockerMetadata{
		Type:      pgpUnlockerType,
		CreatedAt: time.Now(),
		Flags:     []string{"gpg", "encrypted"},
	}

	// Create a PGP unlocker for the remaining tests
	unlocker := secret.NewPGPUnlocker(fs, unlockerDir, metadata)

	// Test getting identity from PGP unlocker
	t.Run("GetIdentity", func(t *testing.T) {
		testPGPUnlockerGetIdentity(t, fs, unlocker, unlockerDir, keyID)
	})

	// Test removing the unlocker
	t.Run("RemoveUnlocker", func(t *testing.T) {
		testRemovePGPUnlocker(t, fs, unlocker, unlockerDir)
	})
}

// testCreatePGPUnlocker creates a vault with a passphrase unlocker, then a
// PGP unlocker for the GPG key keyID, and checks the PGP unlocker's files
// and metadata.
func testCreatePGPUnlocker(
	t *testing.T, fs afero.Fs, stateDir, vaultName, keyID, fingerprint string,
) {
	t.Helper()

	// Set a limited test timeout to avoid hanging
	timer := time.AfterFunc(10*time.Second, func() {
		t.Fatalf("Test timed out after 10 seconds")
	})
	defer timer.Stop()

	mnemonic := testMnemonicBuffer(t)

	// Create a test vault directory structure
	vlt, err := vault.CreateVault(fs, stateDir, vaultName, mnemonic, nil)
	if err != nil {
		t.Fatalf("Failed to create vault: %v", err)
	}

	// Set the current vault
	err = vault.SelectVault(fs, stateDir, vaultName)
	if err != nil {
		t.Fatalf("Failed to select vault: %v", err)
	}

	// Derive long-term key from mnemonic
	ltIdentity, err := agehd.DeriveIdentity(testMnemonic, 0)
	if err != nil {
		t.Fatalf("Failed to derive long-term key: %v", err)
	}

	// Get the vault directory
	vaultDir, err := vlt.GetDirectory()
	if err != nil {
		t.Fatalf("Failed to get vault directory: %v", err)
	}

	// Write long-term public key
	ltPubKeyPath := filepath.Join(vaultDir, "pub.age")

	err = afero.WriteFile(fs, ltPubKeyPath,
		[]byte(ltIdentity.Recipient().String()), secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write long-term public key: %v", err)
	}

	// Unlock the vault
	vlt.Unlock(ltIdentity)

	// Create a passphrase unlocker first (to have current unlocker)
	passphraseBuffer := memguard.NewBufferFromBytes([]byte("test-passphrase"))
	defer passphraseBuffer.Destroy()

	passUnlocker, err := vlt.CreatePassphraseUnlocker(passphraseBuffer)
	if err != nil {
		t.Fatalf("Failed to create passphrase unlocker: %v", err)
	}

	// Verify passphrase unlocker was created
	if passUnlocker == nil {
		t.Fatal("Passphrase unlocker is nil")
	}

	// Now create a PGP unlock key (this will use our custom GPGEncryptFunc)
	pgpUnlocker, err := secret.CreatePGPUnlocker(vlt, keyID, fingerprint)
	if err != nil {
		t.Fatalf("Failed to create PGP unlock key: %v", err)
	}

	// Verify the PGP unlock key was created
	if pgpUnlocker == nil {
		t.Fatal("PGP unlock key is nil")
	}

	// Check if the key has the correct type
	if pgpUnlocker.GetType() != pgpUnlockerType {
		t.Errorf("Expected PGP unlock key type 'pgp', got '%s'", pgpUnlocker.GetType())
	}

	// Check that the ID is the name of the unlocker's directory
	if pgpUnlocker.GetID() != filepath.Base(pgpUnlocker.GetDirectory()) {
		t.Errorf("PGP unlock key ID '%s' is not its directory name '%s'",
			pgpUnlocker.GetID(), filepath.Base(pgpUnlocker.GetDirectory()))
	}

	checkPGPUnlockerFiles(t, fs, pgpUnlocker.GetDirectory())
	checkPGPUnlockerMetadata(t, fs, pgpUnlocker.GetDirectory(), fingerprint)
}

// checkPGPUnlockerFiles checks that the PGP unlocker in unlockerDir has all
// its files.
func checkPGPUnlockerFiles(t *testing.T, fs afero.Fs, unlockerDir string) {
	t.Helper()

	// Check if the key directory exists
	keyExists, err := afero.DirExists(fs, unlockerDir)
	if err != nil {
		t.Fatalf("Failed to check if PGP key directory exists: %v", err)
	}

	if !keyExists {
		t.Errorf("PGP unlock key directory does not exist: %s", unlockerDir)
	}

	// Check if required files exist
	recipientPath := filepath.Join(unlockerDir, "pub.txt")

	recipientExists, err := afero.Exists(fs, recipientPath)
	if err != nil {
		t.Fatalf("Failed to check if recipient file exists: %v", err)
	}

	if !recipientExists {
		t.Errorf("PGP unlock key recipient file does not exist: %s", recipientPath)
	}

	privKeyPath := filepath.Join(unlockerDir, "priv.age.gpg")

	privKeyExists, err := afero.Exists(fs, privKeyPath)
	if err != nil {
		t.Fatalf("Failed to check if private key file exists: %v", err)
	}

	if !privKeyExists {
		t.Errorf("PGP unlock key private key file does not exist: %s", privKeyPath)
	}

	metadataPath := filepath.Join(unlockerDir, unlockerMetadataFile)

	metadataExists, err := afero.Exists(fs, metadataPath)
	if err != nil {
		t.Fatalf("Failed to check if metadata file exists: %v", err)
	}

	if !metadataExists {
		t.Errorf("PGP unlock key metadata file does not exist: %s", metadataPath)
	}

	longtermPath := filepath.Join(unlockerDir, "longterm.age")

	longtermExists, err := afero.Exists(fs, longtermPath)
	if err != nil {
		t.Fatalf("Failed to check if longterm key file exists: %v", err)
	}

	if !longtermExists {
		t.Errorf("PGP unlock key longterm key file does not exist: %s", longtermPath)
	}
}

// checkPGPUnlockerMetadata checks that the metadata of the PGP unlocker in
// unlockerDir names its type and the GPG key by fingerprint.
func checkPGPUnlockerMetadata(
	t *testing.T, fs afero.Fs, unlockerDir, fingerprint string,
) {
	t.Helper()

	// Read and verify metadata
	metadataPath := filepath.Join(unlockerDir, unlockerMetadataFile)

	metadataBytes, err := afero.ReadFile(fs, metadataPath)
	if err != nil {
		t.Fatalf("Failed to read metadata: %v", err)
	}

	var metadata struct {
		ID        string    `json:"id"`
		Type      string    `json:"type"`
		CreatedAt time.Time `json:"createdAt"`
		Flags     []string  `json:"flags"`
		GPGKeyID  string    `json:"gpgKeyId"`
	}

	err = json.Unmarshal(metadataBytes, &metadata)
	if err != nil {
		t.Fatalf("Failed to parse metadata: %v", err)
	}

	if metadata.Type != pgpUnlockerType {
		t.Errorf("Expected metadata type 'pgp', got '%s'", metadata.Type)
	}

	if metadata.GPGKeyID != fingerprint {
		t.Errorf("Expected GPG fingerprint '%s', got '%s'", fingerprint, metadata.GPGKeyID)
	}
}

// testPGPUnlockerGetIdentity writes an age identity encrypted to the GPG key
// keyID into unlockerDir and checks that unlocker decrypts it.
func testPGPUnlockerGetIdentity(
	t *testing.T, fs afero.Fs, unlocker *secret.PGPUnlocker,
	unlockerDir, keyID string,
) {
	t.Helper()

	// Generate an age identity for testing
	ageIdentity, err := age.GenerateX25519Identity()
	if err != nil {
		t.Fatalf("Failed to generate age identity: %v", err)
	}

	// Write the recipient
	recipientPath := filepath.Join(unlockerDir, "pub.txt")

	err = afero.WriteFile(fs, recipientPath,
		[]byte(ageIdentity.Recipient().String()), secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write recipient: %v", err)
	}

	// GPG encrypt the private key using our custom encrypt function
	privKeyBuffer := memguard.NewBufferFromBytes([]byte(ageIdentity.String()))
	defer privKeyBuffer.Destroy()

	encryptedOutput, err := secret.GPGEncryptFunc(privKeyBuffer, keyID)
	if err != nil {
		t.Fatalf("Failed to encrypt with GPG: %v", err)
	}

	// Write the encrypted data to a file
	encryptedPath := filepath.Join(unlockerDir, "priv.age.gpg")

	err = afero.WriteFile(fs, encryptedPath, encryptedOutput, secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write encrypted private key: %v", err)
	}

	// Now try to get the identity - this will use our custom GPGDecryptFunc
	identity, err := unlocker.GetIdentity()
	if err != nil {
		t.Fatalf("Failed to get identity: %v", err)
	}

	// Verify the identity matches
	expectedPubKey := ageIdentity.Recipient().String()
	actualPubKey := identity.Recipient().String()

	if actualPubKey != expectedPubKey {
		t.Errorf("Expected public key '%s', got '%s'", expectedPubKey, actualPubKey)
	}
}

// testRemovePGPUnlocker removes unlocker and checks that unlockerDir is gone.
func testRemovePGPUnlocker(
	t *testing.T, fs afero.Fs, unlocker *secret.PGPUnlocker, unlockerDir string,
) {
	t.Helper()

	// Ensure unlocker directory exists before removal
	keyExists, err := afero.DirExists(fs, unlockerDir)
	if err != nil {
		t.Fatalf("Failed to check if unlocker directory exists: %v", err)
	}

	if !keyExists {
		t.Fatalf("Unlocker directory does not exist: %s", unlockerDir)
	}

	// Remove unlocker
	err = unlocker.Remove()
	if err != nil {
		t.Fatalf("Failed to remove unlocker: %v", err)
	}

	// Verify directory is gone
	keyExists, err = afero.DirExists(fs, unlockerDir)
	if err != nil {
		t.Fatalf("Failed to check if unlocker directory exists: %v", err)
	}

	if keyExists {
		t.Errorf("Unlocker directory still exists after removal: %s", unlockerDir)
	}
}