Throw error on garbage byte array (#4)

bloomfilter.go

@@ -64,9 +64,13 @@ func FromBytes(b []byte) (*BloomFilter, error) {
 	// read strategy
 	strategyByte, err := reader.ReadByte()
 	if err != nil {
-		return nil, errors.New("Failed to read strategy")
+		return nil, fmt.Errorf("Failed to read strategy: %v", err)
 	}
-	strategy := strategyList[int(strategyByte)]
+	strategyIndex := int(strategyByte)
+	if strategyIndex >= len(strategyList) {
+		return nil, fmt.Errorf("Unknown strategy byte: %v", strategyByte)
+	}
+	strategy := strategyList[strategyIndex]
 
 	// read number of hash functions
 	numHashFuncByte, err := reader.ReadByte()
@@ -80,6 +84,9 @@ func FromBytes(b []byte) (*BloomFilter, error) {
 	if err != nil {
 		return nil, fmt.Errorf("Failed to read number of bits: %v", err)
 	}
+	if len(numUint64Bytes) != 4 {
+		return nil, fmt.Errorf("Not a valid uint32 bytes: %v", numUint64Bytes)
+	}
 	numUint64 := binary.BigEndian.Uint32(numUint64Bytes)
 	array := bitarray.NewBitArray(uint64(numUint64) * 64)
 
@@ -89,6 +96,9 @@ func FromBytes(b []byte) (*BloomFilter, error) {
 		if err != nil {
 			return nil, fmt.Errorf("Failed to build bitarray: %v", err)
 		}
+		if len(block) != 8 {
+			return nil, fmt.Errorf("Not a valid uint64 bytes: %v", block)
+		}
 		num := binary.BigEndian.Uint64(block)
 		var pos uint64 = 1 << 63
 		var index uint64

bloomfilter_test.go

@@ -161,6 +161,22 @@ func TestJavaCompatibility(t *testing.T) {
 	}
 }
 
+func TestGarbageByteArray(t *testing.T) {
+	garbageBytes := [][]byte{
+		[]byte("this-is-a-line-of-garbage"),
+		{0},
+		{0, 1},
+		{0, 1, 2},
+		{0, 1, 2, 3, 4, 5},
+	}
+	for _, bytes := range garbageBytes {
+		_, err := FromBytes(bytes)
+		if err == nil {
+			t.Errorf("Expected error on garbage byte array: %v", bytes)
+		}
+	}
+}
+
 func TestBloomFilterInvalidParams(t *testing.T) {
 	// too small error rate
 	_, err := NewBloomFilter(500, 0.0)