fixes based on go-fuzz runs

Author: Ryan Cox

network/buffer.go

@@ -17,6 +17,9 @@ import (
 // size.
 var ErrNotEnoughSpace = errors.New("not enough space")
 
+// ErrUnknownType is returned when attempting to write values of an unknown type
+var ErrUnknownType = errors.New("unknown type")
+
 // Buffer contains the binary representation of multiple ValueLists and state
 // optimally write the next ValueList.
 type Buffer struct {
@@ -248,7 +251,7 @@ func (b *Buffer) writeValues(values []api.Value) error {
 		case api.Derive:
 			binary.Write(b.buffer, binary.BigEndian, uint8(dsTypeDerive))
 		default:
-			panic("unexpected type")
+			return ErrUnknownType
 		}
 	}
 
@@ -264,7 +267,7 @@ func (b *Buffer) writeValues(values []api.Value) error {
 		case api.Derive:
 			binary.Write(b.buffer, binary.BigEndian, int64(v))
 		default:
-			panic("unexpected type")
+			return ErrUnknownType
 		}
 	}
 

network/buffer_test.go

@@ -143,3 +143,16 @@ func TestWriteInt(t *testing.T) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
+
+func TestUnknownType(t *testing.T) {
+	vl, err := Parse([]byte{0x00, 0x06, 0x00, 0x0f, 0x00, 0x01, 0x00, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30}, ParseOpts{})
+	if err != nil {
+		t.Errorf("Error parsing input %v", err)
+	}
+
+	s1 := NewBuffer(0)
+	if err := s1.Write(vl[0]); err == nil {
+		t.Errorf("Writing bad stream should return an error")
+	}
+
+}

network/parse.go

@@ -34,15 +34,30 @@ func Parse(b []byte, opts ParseOpts) ([]api.ValueList, error) {
 	return parse(b, None, opts)
 }
 
+func readUint16(buf *bytes.Buffer) (uint16, error) {
+	read := buf.Next(2)
+	if len(read) != 2 {
+		return 0, ErrInvalid
+	}
+	return binary.BigEndian.Uint16(read), nil
+}
+
 func parse(b []byte, sl SecurityLevel, opts ParseOpts) ([]api.ValueList, error) {
 	var valueLists []api.ValueList
 
 	var state api.ValueList
 	buf := bytes.NewBuffer(b)
 
 	for buf.Len() > 0 {
-		partType := binary.BigEndian.Uint16(buf.Next(2))
-		partLength := int(binary.BigEndian.Uint16(buf.Next(2)))
+		partType, err := readUint16(buf)
+		if err != nil {
+			return nil, ErrInvalid
+		}
+		partLengthUnsigned, err := readUint16(buf)
+		if err != nil {
+			return nil, ErrInvalid
+		}
+		partLength := int(partLengthUnsigned)
 
 		if partLength < 5 || partLength-4 > buf.Len() {
 			return valueLists, fmt.Errorf("invalid length %d", partLength)

network/parse_test.go

@@ -77,3 +77,10 @@ func TestParseString(t *testing.T) {
 		t.Errorf("got (%q, nil), want (\"\", ErrorInvalid)", got)
 	}
 }
+
+func TestOneByte(t *testing.T) {
+	_, err := Parse([]byte{0}, ParseOpts{})
+	if err == nil {
+		t.Errorf("Parsing byte stream containing single zero byte should return an error")
+	}
+}