some panics, dont panic on invalid opcode

vm/native.go

@@ -53,10 +53,7 @@ func sha256Func(input []byte, gas *int64) (output []byte, err error) {
 	// Hash
 	hasher := sha256.New()
 	// CONTRACT: this does not err
-	_, err = hasher.Write(input)
-	if err != nil {
-		panic(err)
-	}
+	hasher.Write(input)
 	return hasher.Sum(nil), nil
 }
 
@@ -71,10 +68,7 @@ func ripemd160Func(input []byte, gas *int64) (output []byte, err error) {
 	// Hash
 	hasher := ripemd160.New()
 	// CONTRACT: this does not err
-	_, err = hasher.Write(input)
-	if err != nil {
-		panic(err)
-	}
+	hasher.Write(input)
 	return LeftPadBytes(hasher.Sum(nil), 32), nil
 }
 

vm/vm.go

@@ -90,11 +90,16 @@ func (vm *VM) EnablePermissions() {
 	vm.perms = true
 }
 
+// XXX: it is the duty of the contract writer to call known permissions
+// we do not convey if a permission is not set
+// (unlike in state/execution, where we guarantee HasPermission is called
+// on known permissions and panics else)
 func HasPermission(appState AppState, acc *Account, perm ptypes.PermFlag) bool {
 	v, err := acc.Permissions.Base.Get(perm)
 	if _, ok := err.(ptypes.ErrValueNotSet); ok {
 		if appState == nil {
-			panic(fmt.Sprintf("Global permission value not set for %b", perm))
+			fmt.Printf("\n\n***** Unknown permission %b! ********\n\n", perm)
+			return false
 		}
 		return HasPermission(nil, appState.GetAccount(ptypes.GlobalPermissionsAddress256), perm)
 	}