Fix byte array and untyped constant obfuscation.

Byte arrays were previously,
obfuscated as byte slices.

Untyped constants are now skipped,
because they cannot be replaced with typed variables.

internal/literals/literals.go

@@ -54,15 +54,20 @@ func Obfuscate(files []*ast.File, info *types.Info, fset *token.FileSet, blackli
 				for _, name := range spec.Names {
 					obj := info.ObjectOf(name)
 
-					// The object itself is blacklisted, e.g. a value that needs to be constant
-					if _, ok := blacklist[obj]; ok {
+					basic, ok := obj.Type().(*types.Basic)
+					if !ok {
+						// skip the block if it contains non basic types
+						return false
+					}
+
+					if basic.Info()&types.IsUntyped != 0 {
+						// skip the block if it contains untyped constants
 						return false
 					}
-				}
 
-				for _, val := range spec.Values {
-					if _, ok := val.(*ast.BasicLit); !ok {
-						return false // skip the block if it contains non basic literals
+					// The object itself is blacklisted, e.g. a value that needs to be constant
+					if _, ok := blacklist[obj]; ok {
+						return false
 					}
 				}
 			}
@@ -79,35 +84,53 @@ func Obfuscate(files []*ast.File, info *types.Info, fset *token.FileSet, blackli
 		case *ast.CompositeLit:
 			byteType := types.Universe.Lookup("byte").Type()
 
-			switch x := info.TypeOf(x.Type).(type) {
+			switch y := info.TypeOf(x.Type).(type) {
 			case *types.Array:
-				if x.Elem() != byteType {
+				if y.Elem() != byteType {
 					return true
 				}
-			case *types.Slice:
-				if x.Elem() != byteType {
-					return true
+
+				data := make([]byte, y.Len())
+
+				for i, el := range x.Elts {
+					lit, ok := el.(*ast.BasicLit)
+					if !ok {
+						return true
+					}
+
+					value, err := strconv.Atoi(lit.Value)
+					if err != nil {
+						return true
+					}
+
+					data[i] = byte(value)
 				}
-			default:
-				return true
-			}
+				cursor.Replace(obfuscateByteArray(data, y.Len()))
 
-			var data []byte
-			for _, el := range x.Elts {
-				lit, ok := el.(*ast.BasicLit)
-				if !ok {
+			case *types.Slice:
+				if y.Elem() != byteType {
 					return true
 				}
 
-				value, err := strconv.Atoi(lit.Value)
-				if err != nil {
-					return true
+				var data []byte
+
+				for _, el := range x.Elts {
+					lit, ok := el.(*ast.BasicLit)
+					if !ok {
+						return true
+					}
+
+					value, err := strconv.Atoi(lit.Value)
+					if err != nil {
+						return true
+					}
+
+					data = append(data, byte(value))
 				}
+				cursor.Replace(obfuscateByteSlice(data))
 
-				data = append(data, byte(value))
 			}
 
-			cursor.Replace(obfuscateBytes(data))
 		case *ast.BasicLit:
 			switch cursor.Name() {
 			case "Values", "Rhs", "Value", "Args", "X", "Y", "Results":
@@ -152,7 +175,7 @@ func obfuscateString(data string) *ast.CallExpr {
 	return callExpr(&ast.Ident{Name: "string"}, block)
 }
 
-func obfuscateBytes(data []byte) *ast.CallExpr {
+func obfuscateByteSlice(data []byte) *ast.CallExpr {
 	obfuscator := randObfuscator()
 	block := obfuscator.obfuscate(data)
 	block.List = append(block.List, &ast.ReturnStmt{
@@ -161,6 +184,56 @@ func obfuscateBytes(data []byte) *ast.CallExpr {
 	return callExpr(&ast.ArrayType{Elt: &ast.Ident{Name: "byte"}}, block)
 }
 
+func obfuscateByteArray(data []byte, length int64) *ast.CallExpr {
+	obfuscator := randObfuscator()
+	block := obfuscator.obfuscate(data)
+
+	arrayType := &ast.ArrayType{
+		Len: &ast.BasicLit{
+			Kind:  token.INT,
+			Value: strconv.Itoa(int(length)),
+		},
+		Elt: &ast.Ident{Name: "byte"},
+	}
+
+	sliceToArray := []ast.Stmt{
+		&ast.DeclStmt{
+			Decl: &ast.GenDecl{
+				Tok: token.VAR,
+				Specs: []ast.Spec{&ast.ValueSpec{
+					Names: []*ast.Ident{{Name: "newdata"}},
+					Type:  arrayType,
+				}},
+			},
+		},
+		&ast.RangeStmt{
+			Key: &ast.Ident{Name: "i"},
+			Tok: token.DEFINE,
+			X:   &ast.Ident{Name: "newdata"},
+			Body: &ast.BlockStmt{List: []ast.Stmt{
+				&ast.AssignStmt{
+					Lhs: []ast.Expr{&ast.IndexExpr{
+						X:     &ast.Ident{Name: "newdata"},
+						Index: &ast.Ident{Name: "i"},
+					}},
+					Tok: token.ASSIGN,
+					Rhs: []ast.Expr{&ast.IndexExpr{
+						X:     &ast.Ident{Name: "data"},
+						Index: &ast.Ident{Name: "i"},
+					}},
+				},
+			}},
+		},
+		&ast.ReturnStmt{Results: []ast.Expr{
+			&ast.Ident{Name: "newdata"},
+		}},
+	}
+
+	block.List = append(block.List, sliceToArray...)
+
+	return callExpr(arrayType, block)
+}
+
 // ConstBlacklist blacklist identifieres used in constant expressions
 func ConstBlacklist(node ast.Node, info *types.Info, blacklist map[types.Object]struct{}) {
 	blacklistObjects := func(node ast.Node) bool {

testdata/scripts/literals.txt

@@ -7,7 +7,7 @@ cmp stderr main.stderr
 cmp stderr normal.stderr
 ! binsubstr main$exe 'garbleDecrypt' 'Lorem' 'ipsum' 'dolor' 'first assign' 'second assign' 'First Line' 'Second Line' 'map value' 'to obfuscate' 'also obfuscate' 'stringTypeField String' 'stringTypeStruct'
 
-binsubstr main$exe 'also skip this' 'skip typed const' 'skip typed var' 'skip typed var assign' 'stringTypeField strType' 'stringType lambda func return' 'testMap1 key' 'testMap2 key' 'testMap3 key' 'testMap1 value' 'testMap3 value' 'testMap1 new value' 'testMap3 new value' 'stringType func param' 'stringType return'
+binsubstr main$exe 'also skip this' 'skip typed const' 'skip typed var' 'skip typed var assign' 'stringTypeField strType' 'stringType lambda func return' 'testMap1 key' 'testMap2 key' 'testMap3 key' 'testMap1 value' 'testMap3 value' 'testMap1 new value' 'testMap3 new value' 'stringType func param' 'stringType return' 'skip untyped const'
 [short] stop # checking that the build is reproducible is slow
 
 # Also check that the binary is reproducible.
@@ -28,7 +28,7 @@ type strucTest struct {
 
 const (
 	cnst      string = "Lorem"
-	multiline        = `First Line
+	multiline string = `First Line
 Second Line`
 )
 
@@ -70,7 +70,7 @@ func main() {
 		field:        "to obfuscate",
 		anotherfield: "also obfuscate",
 	}
-	
+
 	lambda := func() string {
 		return "😅 😅"
 	}()
@@ -98,6 +98,9 @@ type stringTypeStruct struct {
 
 // typedTest types defined from string broke previously
 func typedTest() {
+	const skipUntypedConst = "skip untyped const"
+	stringTypeFunc(skipUntypedConst)
+
 	const skipTypedConst stringType = "skip typed const" // skip
 	var skipTypedVar stringType = "skip typed var"       // skip
 
@@ -158,6 +161,7 @@ func constantTest() {
 
 	const f = "foo" // skip
 	const i = length + len(f)
+	println(length, i)
 }
 
 func byteTest() {
@@ -177,6 +181,14 @@ func byteTest() {
 		print(elm, ", ")
 	}
 	println()
+
+	d := func() [4]byte {
+		return [4]byte{12, 13}
+	}()
+	for _, elm := range d {
+		print(elm, ", ")
+	}
+	println()
 }
 
 func stringTypeFunc(s stringType) stringType {
@@ -197,6 +209,7 @@ new value
 another literal
 also skip this
 1 0 1
+skip untyped const
 skip typed const skip typed var skip typed var assign
 stringTypeField String stringTypeField strType
 stringType lambda func return
@@ -204,6 +217,8 @@ stringType func param
 stringType return
 foo
 foo
+3 6
 12, 13, 
 12, 13, 
 12, 13, 
+12, 13, 0, 0,