feat: production-ready domain control dashboard

internal/secure/secure.go

@@ -0,0 +1,122 @@
+package secure
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/argon2"
+	"golang.org/x/crypto/chacha20poly1305"
+)
+
+const (
+	argonMemory  = 64 * 1024
+	argonTime    = 3
+	argonThreads = 2
+	argonKeyLen  = 32
+)
+
+type Cipher struct {
+	key []byte
+}
+
+func LoadCipher(path string) (*Cipher, error) {
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read master key: %w", err)
+	}
+	raw = []byte(strings.TrimSpace(string(raw)))
+	key, err := base64.RawStdEncoding.DecodeString(string(raw))
+	if err != nil {
+		key, err = base64.StdEncoding.DecodeString(string(raw))
+	}
+	if err != nil || len(key) != chacha20poly1305.KeySize {
+		return nil, errors.New("master key must be a base64-encoded 32-byte value")
+	}
+	return &Cipher{key: key}, nil
+}
+
+func (c *Cipher) Encrypt(plaintext string) (ciphertext, nonce []byte, err error) {
+	aead, err := chacha20poly1305.NewX(c.key)
+	if err != nil {
+		return nil, nil, err
+	}
+	nonce = make([]byte, chacha20poly1305.NonceSizeX)
+	if _, err = rand.Read(nonce); err != nil {
+		return nil, nil, fmt.Errorf("create encryption nonce: %w", err)
+	}
+	return aead.Seal(nil, nonce, []byte(plaintext), nil), nonce, nil
+}
+
+func (c *Cipher) Decrypt(ciphertext, nonce []byte) (string, error) {
+	aead, err := chacha20poly1305.NewX(c.key)
+	if err != nil {
+		return "", err
+	}
+	plaintext, err := aead.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return "", errors.New("could not decrypt stored credential")
+	}
+	return string(plaintext), nil
+}
+
+func (c *Cipher) Fingerprint(value string) string {
+	mac := hmac.New(sha256.New, c.key)
+	_, _ = mac.Write([]byte(value))
+	return base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
+}
+
+func RandomToken(bytes int) (string, error) {
+	buf := make([]byte, bytes)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(buf), nil
+}
+
+func HashToken(token string) string {
+	sum := sha256.Sum256([]byte(token))
+	return base64.RawURLEncoding.EncodeToString(sum[:])
+}
+
+func HashPassword(password string) (string, error) {
+	if len(password) < 12 {
+		return "", errors.New("password must contain at least 12 characters")
+	}
+	salt := make([]byte, 16)
+	if _, err := rand.Read(salt); err != nil {
+		return "", err
+	}
+	hash := argon2.IDKey([]byte(password), salt, argonTime, argonMemory, argonThreads, argonKeyLen)
+	return fmt.Sprintf("argon2id$v=19$m=%d,t=%d,p=%d$%s$%s", argonMemory, argonTime, argonThreads,
+		base64.RawStdEncoding.EncodeToString(salt), base64.RawStdEncoding.EncodeToString(hash)), nil
+}
+
+func VerifyPassword(encoded, password string) bool {
+	parts := strings.Split(encoded, "$")
+	if len(parts) != 5 || parts[0] != "argon2id" || parts[1] != "v=19" {
+		return false
+	}
+	var memory uint32
+	var iterations uint32
+	var threads uint8
+	if _, err := fmt.Sscanf(parts[2], "m=%d,t=%d,p=%d", &memory, &iterations, &threads); err != nil {
+		return false
+	}
+	salt, err := base64.RawStdEncoding.DecodeString(parts[3])
+	if err != nil {
+		return false
+	}
+	want, err := base64.RawStdEncoding.DecodeString(parts[4])
+	if err != nil {
+		return false
+	}
+	got := argon2.IDKey([]byte(password), salt, iterations, memory, threads, uint32(len(want)))
+	return subtle.ConstantTimeCompare(got, want) == 1
+}

internal/secure/secure_test.go

@@ -0,0 +1,59 @@
+package secure
+
+import (
+	"encoding/base64"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCipherRoundTripAndFingerprint(t *testing.T) {
+	t.Parallel()
+	dir := t.TempDir()
+	key := make([]byte, 32)
+	for index := range key {
+		key[index] = byte(index + 1)
+	}
+	path := filepath.Join(dir, "master-key")
+	if err := os.WriteFile(path, []byte(base64.RawStdEncoding.EncodeToString(key)), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	cipher, err := LoadCipher(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ciphertext, nonce, err := cipher.Encrypt("hetzner-token-value")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(ciphertext) == "hetzner-token-value" {
+		t.Fatal("token was not encrypted")
+	}
+	plaintext, err := cipher.Decrypt(ciphertext, nonce)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if plaintext != "hetzner-token-value" {
+		t.Fatalf("got %q", plaintext)
+	}
+	if cipher.Fingerprint("same") != cipher.Fingerprint("same") || cipher.Fingerprint("same") == cipher.Fingerprint("different") {
+		t.Fatal("fingerprint must be deterministic and token-specific")
+	}
+}
+
+func TestPasswordHash(t *testing.T) {
+	t.Parallel()
+	hash, err := HashPassword("a secure password")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !VerifyPassword(hash, "a secure password") {
+		t.Fatal("expected password verification to succeed")
+	}
+	if VerifyPassword(hash, "wrong password") {
+		t.Fatal("wrong password verified")
+	}
+	if _, err := HashPassword("short"); err == nil {
+		t.Fatal("short password was accepted")
+	}
+}