prevent variant types from recursing

msoleps.go

@@ -29,7 +29,7 @@
 //       if oerr := props.Reset(doc); oerr != nil {
 //         log.Fatal(oerr)
 //       }
-//       for prop := range props.Property {
+//       for _, prop := range props.Property {
 //         fmt.Printf("Name: %s; Type: %s; Value: %v", prop.Name, prop.Type(), prop)
 //       }
 //     }
@@ -134,7 +134,7 @@ func (r *Reader) start(rdr io.Reader) error {
 			r.Property[i].T = types.Null{}
 			continue
 		}
-		t, _ := types.Evaluate(r.buf[int(v.offset+pss.offsetA):])
+		t, _ := types.Evaluate(r.buf[int(v.offset+pss.offsetA):]) // ignore errors for now as not all types implemented
 		if t.Type() == "CodeString" {
 			cs := t.(*types.CodeString)
 			cs.SetId(ps.code)
@@ -162,7 +162,7 @@ func (r *Reader) start(rdr io.Reader) error {
 			r.Property[i].T = types.Null{}
 			continue
 		}
-		t, _ := types.Evaluate(r.buf[int(v.offset+pss.offsetB):])
+		t, _ := types.Evaluate(r.buf[int(v.offset+pss.offsetB):]) // ignore errors for now as not all types implemented
 		if t.Type() == "CodeString" {
 			cs := t.(*types.CodeString)
 			cs.SetId(psb.code)

msoleps_test.go

@@ -9,6 +9,7 @@ var (
 	testDocSum = "test/DocumentSummaryInformation"
 	testSum    = "test/SummaryInformation"
 	testSum1   = "test/SummaryInformation1"
+	testBad    = "test/SummaryInformationBad"
 )
 
 func testFile(t *testing.T, path string) *Reader {

types/types.go

@@ -34,7 +34,8 @@ type Type interface {
 }
 
 const (
-	vector uint16 = iota + 1
+	scalar uint16 = iota
+	vector
 	array
 )
 
@@ -52,8 +53,13 @@ func Evaluate(b []byte) (Type, error) {
 		return MakeVector(f, b[4:])
 	case array:
 		return MakeArray(f, b[4:])
+	case scalar:
+		if id != VT_VARIANT { // a VT_VARIANT can only be in a vector or array
+			return f(b[4:])
+		}
 	}
-	return f(b[4:])
+	return I1(0), ErrUnknownType
+
 }
 
 type TypeID uint16

types/vectorArray.go

@@ -74,6 +74,7 @@ func (a Array) Length() int {
 	return 0
 }
 
+// not implemented yet
 func MakeArray(f MakeType, b []byte) (Type, error) {
 	return Array{}, nil
 }
@@ -95,7 +96,18 @@ func (v Variant) Length() int {
 }
 
 func MakeVariant(b []byte) (Type, error) {
-	t, err := Evaluate(b)
+	if len(b) < 4 || binary.LittleEndian.Uint16(b[2:4]) != scalar { // only scalar values allowed
+		return Variant{}, ErrType
+	}
+	id := TypeID(binary.LittleEndian.Uint16(b[:2]))
+	if id == VT_VARIANT {
+		return Variant{}, ErrType // no recursive types allowed
+	}
+	f, ok := MakeTypes[id]
+	if !ok {
+		return I1(0), ErrUnknownType
+	}
+	t, err := f(b[4:])
 	if err != nil {
 		return Variant{}, err
 	}