mfer/internal/cli/signing_test.go

//nolint:testpackage // white-box tests exercise unexported internals
package cli

import (
	"bufio"
	"io"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/ProtonMail/go-crypto/openpgp/packet"
	"github.com/creack/pty"
	"github.com/spf13/afero"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

const (
	testFlagSignKey = "--sign-key"
	testKeyFile     = "/key.asc"
)

// TestGenAndFreshenSignWithKeyFile runs gen, then freshen after a file is
// added, with --sign-key naming a key file: one key with no passphrase and
// one protected by the passphrase in MFER_SIGN_KEY_PASSPHRASE. check
// --require-signature must accept each manifest as signed by that key.
// freshen leaves its manifest out of the listing only on the real
// filesystem, so the test uses that.
func TestGenAndFreshenSignWithKeyFile(t *testing.T) {
	for name, passphrase := range map[string][]byte{
		"unprotected": nil,
		"protected":   []byte("passphrase"),
	} {
		t.Run(name, func(t *testing.T) {
			t.Setenv(envSignKeyPassphrase, string(passphrase))

			secretKey, fingerprint := testSecretKey(t, passphrase, nil)

			fs := afero.NewOsFs()
			keyFile := filepath.Join(t.TempDir(), "key.asc")
			root := t.TempDir()
			manifestPath := filepath.Join(root, defaultManifestName)

			require.NoError(t, afero.WriteFile(fs, keyFile, secretKey, 0o600))
			writeTestFile(t, fs, filepath.Join(root, testFileTxt), "hello")

			opts := testOpts([]string{
				testApp, cmdGenerate, "-q", testFlagSignKey, keyFile,
				"-o", manifestPath, root,
			}, fs)
			require.Equal(t, 0, runCLI(opts), testStderr(t, opts))

			check := []string{
				testApp, cmdCheck, "-q",
				"--" + flagRequireSignature, fingerprint, manifestPath,
			}

			opts = testOpts(check, fs)
			require.Equal(t, 0, runCLI(opts), testStderr(t, opts))

			writeTestFile(t, fs, filepath.Join(root, "added.txt"), "added")

			opts = testOpts([]string{
				testApp, cmdFreshen, "-q", testFlagSignKey, keyFile, manifestPath,
			}, fs)
			require.Equal(t, 0, runCLI(opts), testStderr(t, opts))

			opts = testOpts(check, fs)
			require.Equal(t, 0, runCLI(opts), testStderr(t, opts))
			assert.Len(t, manifestFiles(t, fs, manifestPath), 2)
		})
	}
}

// TestSignWithProtectedKeyNeedsPassphrase runs gen with a protected key,
// with MFER_SIGN_KEY_PASSPHRASE empty and no terminal to ask on. gen must
// fail, naming the variable, and write no manifest.
func TestSignWithProtectedKeyNeedsPassphrase(t *testing.T) {
	t.Setenv(envSignKeyPassphrase, "")

	secretKey, _ := testSecretKey(t, []byte("secret"), nil)

	fs := afero.NewMemMapFs()
	require.NoError(t, afero.WriteFile(fs, testKeyFile, secretKey, 0o600))
	require.NoError(t, fs.MkdirAll(testDir, 0o755))
	writeTestFile(t, fs, testFile1, "hello")

	opts := testOpts([]string{
		testApp, cmdGenerate, "-q", testFlagSignKey, testKeyFile,
		"-o", testMF, testDir,
	}, fs)
	assert.Equal(t, 1, runCLI(opts))
	assert.Contains(t, testStderr(t, opts),
		"signing key is protected: set MFER_SIGN_KEY_PASSPHRASE to its passphrase")

	exists, err := afero.Exists(fs, testMF)
	require.NoError(t, err)
	assert.False(t, exists)
}

// TestSignWithKeyThatCannotSignFailsFirst runs gen on a directory and
// freshen on a manifest, neither of which exists, with keys that cannot
// sign: a protected key with a wrong MFER_SIGN_KEY_PASSPHRASE, a key that
// expired in 2020, and a version 6 key. Each run must fail on the key: it
// checks the key before it reads any file, so a missing file goes
// unnoticed.
func TestSignWithKeyThatCannotSignFailsFirst(t *testing.T) {
	t.Setenv(envSignKeyPassphrase, "wrong")

	wrongPassphrase, _ := testSecretKey(t, []byte("right"), nil)

	made := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
	expired, _ := testSecretKey(t, nil, &packet.Config{
		Algorithm:       packet.PubKeyAlgoEdDSA,
		Time:            func() time.Time { return made },
		KeyLifetimeSecs: uint32((24 * time.Hour).Seconds()),
	})

	version6, _ := testSecretKey(t, nil, &packet.Config{
		Algorithm: packet.PubKeyAlgoEd25519,
		V6Keys:    true,
	})

	for want, secretKey := range map[string][]byte{
		"unlock signing key":                           wrongPassphrase,
		"signing key cannot sign":                      expired,
		"signing key must be an OpenPGP version 4 key": version6,
	} {
		fs := afero.NewMemMapFs()
		require.NoError(t, afero.WriteFile(fs, testKeyFile, secretKey, 0o600))

		for _, args := range [][]string{
			{
				testApp, cmdGenerate, "-q", testFlagSignKey, testKeyFile,
				"-o", testMF, "/missing",
			},
			{testApp, cmdFreshen, "-q", testFlagSignKey, testKeyFile, "/missing.mf"},
		} {
			opts := testOpts(args, fs)
			assert.Equal(t, 1, runCLI(opts), args[1], want)
			assert.Contains(t, testStderr(t, opts), testKeyFile+": "+want, args[1])
		}
	}
}

// TestGenAsksForPassphraseOnTerminal runs gen with a protected key, no
// MFER_SIGN_KEY_PASSPHRASE, and a terminal as stdin and stderr. gen must
// ask for the passphrase on stderr, and sign with what is typed after the
// prompt.
func TestGenAsksForPassphraseOnTerminal(t *testing.T) {
	t.Setenv(envSignKeyPassphrase, "")

	secretKey, fingerprint := testSecretKey(t, []byte("passphrase"), nil)

	fs := afero.NewOsFs()
	keyFile := filepath.Join(t.TempDir(), "key.asc")
	root := t.TempDir()
	manifestPath := filepath.Join(root, defaultManifestName)

	require.NoError(t, afero.WriteFile(fs, keyFile, secretKey, 0o600))
	writeTestFile(t, fs, filepath.Join(root, testFileTxt), "hello")

	terminal, tty, err := pty.Open()
	require.NoError(t, err)

	t.Cleanup(func() { _ = terminal.Close() })

	opts := testOpts([]string{
		testApp, cmdGenerate, "-q", testFlagSignKey, keyFile,
		"-o", manifestPath, root,
	}, fs)
	opts.Stdin = tty
	opts.Stderr = tty

	exitCode := make(chan int, 1)

	go func() {
		exitCode <- runCLI(opts)

		// Once gen has ended, reading the terminal fails instead of
		// waiting for a prompt that will not come.
		_ = tty.Close()
	}()

	prompt := "Passphrase for " + keyFile + ": "
	output := bufio.NewReader(terminal)
	written := ""

	for !strings.HasSuffix(written, prompt) {
		b, err := output.ReadByte()
		require.NoError(t, err, "gen wrote %q and no prompt", written)

		written += string(b)
	}

	_, err = terminal.WriteString("passphrase\n")
	require.NoError(t, err)

	code := <-exitCode
	rest, _ := io.ReadAll(output)
	require.Equal(t, 0, code, "gen wrote %q", rest)

	check := testOpts([]string{
		testApp, cmdCheck, "-q",
		"--" + flagRequireSignature, fingerprint, manifestPath,
	}, fs)
	require.Equal(t, 0, runCLI(check), testStderr(t, check))
}