Fix crashers found via fuzzing

fuzz.go

@@ -0,0 +1,14 @@
+// +build gofuzz
+
+package stalecucumber
+
+import (
+	"bytes"
+)
+
+func Fuzz(data []byte) int {
+	if _, err := Unpickle(bytes.NewReader(data)); err != nil {
+		return 0
+	}
+	return 1
+}

fuzz_test.go

@@ -0,0 +1,20 @@
+package stalecucumber
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestFuzzCrashers(t *testing.T) {
+
+	var crashers = []string{
+		"}}(s",       //protocol_0 SETITEM hash of unhashable
+		"((d}d",      //protocol_0.go opcode_DICT hash of unhashable
+		"}(}(a}u",    //protocol_1 SETITEMS hash of unhashable
+		"(p0\nj0000", //pickle_machine flushMemoBuffer index out of range
+	}
+
+	for _, f := range crashers {
+		Unpickle(strings.NewReader(f))
+	}
+}

protocol_0.go

@@ -3,6 +3,7 @@ package stalecucumber
 import "strconv"
 import "fmt"
 import "math/big"
+import "errors"
 
 //import "unicode/utf8"
 import "unicode/utf16"
@@ -354,7 +355,19 @@ Build a dict out of the topmost stack slice, after markobject.
 Stack before: [mark, stackslice]
 Stack after: [dict]
 **/
-func (pm *PickleMachine) opcode_DICT() error {
+func (pm *PickleMachine) opcode_DICT() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("Unknown panic")
+			}
+		}
+	}()
 	markIndex, err := pm.findMark()
 	if err != nil {
 		return err
@@ -391,7 +404,19 @@ Add a key+value pair to an existing dict.
 Stack before: [dict, any, any]
 Stack after: [dict]
 **/
-func (pm *PickleMachine) opcode_SETITEM() error {
+func (pm *PickleMachine) opcode_SETITEM() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("Unknown panic")
+			}
+		}
+	}()
 	v, err := pm.pop()
 	if err != nil {
 		return err

protocol_1.go

@@ -1,6 +1,7 @@
 package stalecucumber
 
 import "fmt"
+import "errors"
 
 /**
 Opcode: BININT (0x4a)
@@ -272,7 +273,19 @@ Add an arbitrary number of key+value pairs to an existing dict.
 Stack before: [dict, mark, stackslice]
 Stack after: [dict]
 **/
-func (pm *PickleMachine) opcode_SETITEMS() error {
+func (pm *PickleMachine) opcode_SETITEMS() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("Unknown panic")
+			}
+		}
+	}()
 	markIndex, err := pm.findMark()
 	if err != nil {
 		return err
@@ -333,9 +346,21 @@ Read an object from the memo and push it on the stack.
 Stack before: []
 Stack after: [any]
 **/
-func (pm *PickleMachine) opcode_BINGET() error {
+func (pm *PickleMachine) opcode_BINGET() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("Unknown panic")
+			}
+		}
+	}()
 	var index uint8
-	err := pm.readBinaryInto(&index, false)
+	err = pm.readBinaryInto(&index, false)
 	if err != nil {
 		return err
 	}
@@ -362,9 +387,21 @@ Read an object from the memo and push it on the stack.
 Stack before: []
 Stack after: [any]
 **/
-func (pm *PickleMachine) opcode_LONG_BINGET() error {
+func (pm *PickleMachine) opcode_LONG_BINGET() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("Unknown panic")
+			}
+		}
+	}()
 	var index int32
-	err := pm.readBinaryInto(&index, false)
+	err = pm.readBinaryInto(&index, false)
 	if err != nil {
 		return err
 	}