Updated PBKDF2 hasher with more complex format handling

hashing/hashing_test.go

@@ -126,22 +126,29 @@ func TestArgon2ID(t *testing.T) {
 
 func TestPBKDF2(t *testing.T) {
 	password := "test-password"
-
-	// Test base64.
-	hasher := NewPBKDF2Hasher(defaultPBKDF2SaltSize, defaultPBKDF2Iterations, defaultPBKDF2Algorithm, Base64, defaultPBKDF2KeyLen)
-
-	passwordHash, err := hasher.Hash(password)
-
-	assert.Nil(t, err)
-	assert.True(t, hasher.Compare(password, passwordHash))
-	assert.False(t, hasher.Compare("other", passwordHash))
-
-	// Test UTF8.
-	hasher = NewPBKDF2Hasher(defaultPBKDF2SaltSize, defaultPBKDF2Iterations, defaultPBKDF2Algorithm, UTF8, defaultPBKDF2KeyLen)
-
-	passwordHash, err = hasher.Hash(password)
-
-	assert.Nil(t, err)
-	assert.True(t, hasher.Compare(password, passwordHash))
-	assert.False(t, hasher.Compare("other", passwordHash))
+	b64Hasher := NewPBKDF2Hasher(defaultPBKDF2SaltSize, defaultPBKDF2Iterations, defaultPBKDF2Algorithm, Base64, defaultPBKDF2KeyLen)
+	utf8Hasher := NewPBKDF2Hasher(defaultPBKDF2SaltSize, defaultPBKDF2Iterations, defaultPBKDF2Algorithm, UTF8, defaultPBKDF2KeyLen)
+
+	t.Run("OlderFormat", func(t *testing.T) {
+		t.Run("Base64", func(t *testing.T) {
+			passwordHash, err := b64Hasher.Hash(password)
+
+			assert.Nil(t, err)
+			assert.True(t, b64Hasher.Compare(password, passwordHash))
+			assert.False(t, b64Hasher.Compare("other", passwordHash))
+		})
+		t.Run("UTF8", func(t *testing.T) {
+			passwordHash, err := utf8Hasher.Hash(password)
+
+			assert.Nil(t, err)
+			assert.True(t, utf8Hasher.Compare(password, passwordHash))
+			assert.False(t, utf8Hasher.Compare("other", passwordHash))
+		})
+	})
+
+	t.Run("PHC-SF-Spec", func(t *testing.T) {
+		passwordHash := "$pbkdf2-sha512$i=10000,l=32$/DsNR8DBuoF/MxzLY+QVaw$YNfYNfT+6yT2blLrXKKR8Ll+aesgHYqSOtFTBsyscRM"
+		assert.True(t, b64Hasher.Compare(password, passwordHash))
+		assert.False(t, b64Hasher.Compare("other", passwordHash))
+	})
 }

hashing/pbkdf2.go

@@ -23,34 +23,32 @@
 	keyLen       int
 }
 
-func NewPBKDF2Hasher(saltSize int, iterations int, algorithm string, saltEncoding string, keylen int) HashComparer {
+func NewPBKDF2Hasher(saltSize int, iterations int, algorithm string, saltEncoding string, keyLen int) HashComparer {
 	return pbkdf2Hasher{
 		saltSize:     saltSize,
 		iterations:   iterations,
 		algorithm:    algorithm,
 		saltEncoding: preferredEncoding(saltEncoding),
-		keyLen:       keylen,
+		keyLen:       keyLen,
 	}
 }
 
 /*
 * PBKDF2 methods are adapted from github.com/brocaar/chirpstack-application-server, some comments included.
  */
 
-// Hash function reference may be found at https://github.com/brocaar/chirpstack-application-server/blob/master/internal/storage/user.go#L421.
-
-// Generate the hash of a password for storage in the database.
-// NOTE: We store the details of the hashing algorithm with the hash itself,
-// making it easy to recreate the hash for password checking, even if we change
-// the default criteria here.
+// Hash function generates a hash of the supplied password. The hash
+// can then be stored directly in the database. The return hash will
+// contain options according to the PHC String format found at
+// https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md
 func (h pbkdf2Hasher) Hash(password string) (string, error) {
 	// Generate a random salt value with the given salt size.
 	salt := make([]byte, h.saltSize)
 	_, err := rand.Read(salt)
 
-	// We need to ensure that salt doesn contain $, which is 36 in decimal.
-	// So we check if there'sbyte that represents $ and change it with a random number in the range 0-35
-	//// This is far from ideal, but should be good enough with a reasonable salt size.
+	// We need to ensure that salt doesn't contain $, which is 36 in decimal.
+	// So we check if there's byte that represents $ and change it with a random number in the range 0-35
+	// // This is far from ideal, but should be good enough with a reasonable salt size.
 	for i := 0; i < len(salt); i++ {
 		if salt[i] == 36 {
 			n, err := rand.Int(rand.Reader, big.NewInt(35))
@@ -69,52 +67,125 @@
 	return h.hashWithSalt(password, salt, h.iterations, h.algorithm, h.keyLen), nil
 }
 
-// HashCompare verifies that passed password hashes to the same value as the
+// Compare verifies that passed password hashes to the same value as the
 // passed passwordHash.
 // Reference: https://github.com/brocaar/chirpstack-application-server/blob/master/internal/storage/user.go#L458.
+// Parsing reference: https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md
 func (h pbkdf2Hasher) Compare(password string, passwordHash string) bool {
-	hashSplit := strings.Split(passwordHash, "$")
-
-	if len(hashSplit) != 5 {
-		log.Errorf("invalid PBKDF2 hash supplied, expected length 5, got: %d", len(hashSplit))
-		return false
-	}
-
-	algorithm := hashSplit[1]
+	hashSplit := h.getFields(passwordHash)
+
+	var (
+		err            error
+		algorithm      string
+		paramString    string
+		hashedPassword []byte
+		salt           []byte
+		iterations     int
+		keyLen         int
+	)
+	if hashSplit[0] == "PBKDF2" {
+		algorithm = hashSplit[1]
+		iterations, err = strconv.Atoi(hashSplit[2])
+		if err != nil {
+			log.Errorf("iterations error: %s", err)
+			return false
+		}
 
-	iterations, err := strconv.Atoi(hashSplit[2])
-	if err != nil {
-		log.Errorf("iterations error: %s", err)
-		return false
-	}
+		switch h.saltEncoding {
+		case UTF8:
+			salt = []byte(hashSplit[3])
+		default:
+			var err error
+			salt, err = base64.StdEncoding.DecodeString(hashSplit[3])
+			if err != nil {
+				log.Errorf("base64 salt error: %s", err)
+				return false
+			}
+		}
 
-	var salt []byte
-	switch h.saltEncoding {
-	case UTF8:
-		salt = []byte(hashSplit[3])
-	default:
-		salt, err = base64.StdEncoding.DecodeString(hashSplit[3])
+		hashedPassword, err = base64.StdEncoding.DecodeString(hashSplit[4])
 		if err != nil {
-			log.Errorf("base64 salt error: %s", err)
+			log.Errorf("base64 hash decoding error: %s", err)
 			return false
 		}
+		keyLen = len(hashedPassword)
+
+	} else if hashSplit[0] == "pbkdf2-sha512" {
+		algorithm = "sha512"
+		paramString = hashSplit[1]
+
+		opts := strings.Split(paramString, ",")
+		for _, opt := range opts {
+			parts := strings.Split(opt, "=")
+			for i := 0; i < len(parts); i += 2 {
+				key := parts[i]
+				val := parts[i+1]
+				switch key {
+				case "i":
+					iterations, _ = strconv.Atoi(val)
+				case "l":
+					keyLen, _ = strconv.Atoi(val)
+				default:
+					log.Errorf("unknown options key (\"%s\")", key)
+					return false
+				}
+			}
+		}
+
+		switch h.saltEncoding {
+		case UTF8:
+			salt = []byte(hashSplit[2])
+		default:
+			var err error
+			salt, err = base64.StdEncoding.WithPadding(base64.NoPadding).DecodeString(hashSplit[2])
+			if err != nil {
+				log.Errorf("base64 salt error: %s", err)
+				return false
+			}
+		}
+
+		hashedPassword, err = base64.StdEncoding.WithPadding(base64.NoPadding).DecodeString(hashSplit[3])
+	} else {
+		log.Errorf("invalid PBKDF2 hash supplied, unrecognized format \"%s\"", hashSplit[0])
+		return false
 	}
 
-	hashedPassword, err := base64.StdEncoding.DecodeString(hashSplit[4])
+	newHash := h.hashWithSalt(password, salt, iterations, algorithm, keyLen)
+	hashSplit = h.getFields(newHash)
+	newHashedPassword, err := base64.StdEncoding.DecodeString(hashSplit[4])
 	if err != nil {
-		log.Errorf("base64 hash decoding error: %s", err)
+		log.Errorf("base64 salt error: %s", err)
 		return false
 	}
 
-	keylen := len(hashedPassword)
+	return h.compareBytes(hashedPassword, newHashedPassword)
+}
+
+func (h pbkdf2Hasher) compareBytes(a, b []byte) bool {
+	for i, x := range a {
+		if b[i] != x {
+			return false
+		}
+	}
+	return true
+}
 
-	return passwordHash == h.hashWithSalt(password, salt, iterations, algorithm, keylen)
+func (h pbkdf2Hasher) getFields(passwordHash string) []string {
+	hashSplit := strings.FieldsFunc(passwordHash, func(r rune) bool {
+		switch r {
+		case '$':
+			return true
+		default:
+			return false
+		}
+	})
+	return hashSplit
 }
 
 // Reference: https://github.com/brocaar/chirpstack-application-server/blob/master/internal/storage/user.go#L432.
 func (h pbkdf2Hasher) hashWithSalt(password string, salt []byte, iterations int, algorithm string, keylen int) string {
 	// Generate the hashed password. This should be a little painful, adjust ITERATIONS
-	// if it needs performance tweeking.  Greatly depends on the hardware.
+	// if it needs performance tweaking.  Greatly depends on the hardware.
 	// NOTE: We store these details with the returned hashed, so changes will not
 	// affect our ability to do password compares.
 	shaHash := sha512.New