neorpc: add WS notification filter IsValid functionality

Additional check of filters parameters added for filter validation.

Closes #3241.

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>

docs/notifications.md

@@ -85,7 +85,8 @@ Recognized stream names:
  * `notification_from_execution`
    Filter: `contract` field containing a string with hex-encoded Uint160 (LE
    representation) and/or `name` field containing a string with execution 
-   notification name.
+   notification name which should be a valid UTF-8 string not longer than 
+   32 bytes.
  * `transaction_executed`
    Filter: `state` field containing `HALT` or `FAULT` string for successful
    and failed executions respectively and/or `container` field containing

pkg/neorpc/filters.go

@@ -1,8 +1,13 @@
 package neorpc
 
 import (
+	"errors"
+	"fmt"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempoolevent"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
 )
 
 type (
@@ -49,6 +54,16 @@ type (
 	}
 )
 
+// SubscriptionFilter is an interface for all subscription filters.
+type SubscriptionFilter interface {
+	// IsValid checks whether the filter is valid and returns
+	// a specific [ErrInvalidSubscriptionFilter] error if not.
+	IsValid() error
+}
+
+// ErrInvalidSubscriptionFilter is returned when the subscription filter is invalid.
+var ErrInvalidSubscriptionFilter = errors.New("invalid subscription filter")
+
 // Copy creates a deep copy of the BlockFilter. It handles nil BlockFilter correctly.
 func (f *BlockFilter) Copy() *BlockFilter {
 	if f == nil {
@@ -70,6 +85,11 @@ func (f *BlockFilter) Copy() *BlockFilter {
 	return res
 }
 
+// IsValid implements SubscriptionFilter interface.
+func (f BlockFilter) IsValid() error {
+	return nil
+}
+
 // Copy creates a deep copy of the TxFilter. It handles nil TxFilter correctly.
 func (f *TxFilter) Copy() *TxFilter {
 	if f == nil {
@@ -87,6 +107,11 @@ func (f *TxFilter) Copy() *TxFilter {
 	return res
 }
 
+// IsValid implements SubscriptionFilter interface.
+func (f TxFilter) IsValid() error {
+	return nil
+}
+
 // Copy creates a deep copy of the NotificationFilter. It handles nil NotificationFilter correctly.
 func (f *NotificationFilter) Copy() *NotificationFilter {
 	if f == nil {
@@ -104,6 +129,14 @@ func (f *NotificationFilter) Copy() *NotificationFilter {
 	return res
 }
 
+// IsValid implements SubscriptionFilter interface.
+func (f NotificationFilter) IsValid() error {
+	if f.Name != nil && len(*f.Name) > runtime.MaxEventNameLen {
+		return fmt.Errorf("%w: NotificationFilter name parameter must be less than %d", ErrInvalidSubscriptionFilter, runtime.MaxEventNameLen)
+	}
+	return nil
+}
+
 // Copy creates a deep copy of the ExecutionFilter. It handles nil ExecutionFilter correctly.
 func (f *ExecutionFilter) Copy() *ExecutionFilter {
 	if f == nil {
@@ -121,6 +154,17 @@ func (f *ExecutionFilter) Copy() *ExecutionFilter {
 	return res
 }
 
+// IsValid implements SubscriptionFilter interface.
+func (f ExecutionFilter) IsValid() error {
+	if f.State != nil {
+		if *f.State != vmstate.Halt.String() && *f.State != vmstate.Fault.String() {
+			return fmt.Errorf("%w: ExecutionFilter state parameter must be either %s or %s", ErrInvalidSubscriptionFilter, vmstate.Halt, vmstate.Fault)
+		}
+	}
+
+	return nil
+}
+
 // Copy creates a deep copy of the NotaryRequestFilter. It handles nil NotaryRequestFilter correctly.
 func (f *NotaryRequestFilter) Copy() *NotaryRequestFilter {
 	if f == nil {
@@ -141,3 +185,8 @@ func (f *NotaryRequestFilter) Copy() *NotaryRequestFilter {
 	}
 	return res
 }
+
+// IsValid implements SubscriptionFilter interface.
+func (f NotaryRequestFilter) IsValid() error {
+	return nil
+}

pkg/neorpc/rpcevent/filter.go

@@ -13,7 +13,7 @@ type (
 	// filter notifications.
 	Comparator interface {
 		EventID() neorpc.EventID
-		Filter() any
+		Filter() neorpc.SubscriptionFilter
 	}
 	// Container is an interface required from notification event to be able to
 	// pass filter.

pkg/neorpc/rpcevent/filter_test.go

@@ -18,7 +18,7 @@ import (
 type (
 	testComparator struct {
 		id     neorpc.EventID
-		filter any
+		filter neorpc.SubscriptionFilter
 	}
 	testContainer struct {
 		id  neorpc.EventID
@@ -29,7 +29,7 @@ type (
 func (c testComparator) EventID() neorpc.EventID {
 	return c.id
 }
-func (c testComparator) Filter() any {
+func (c testComparator) Filter() neorpc.SubscriptionFilter {
 	return c.filter
 }
 func (c testContainer) EventID() neorpc.EventID {

pkg/rpcclient/wsclient.go

@@ -127,7 +127,7 @@ func (r *blockReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *blockReceiver) Filter() any {
+func (r *blockReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -174,7 +174,7 @@ func (r *headerOfAddedBlockReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *headerOfAddedBlockReceiver) Filter() any {
+func (r *headerOfAddedBlockReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -220,7 +220,7 @@ func (r *txReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *txReceiver) Filter() any {
+func (r *txReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -267,7 +267,7 @@ func (r *executionNotificationReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *executionNotificationReceiver) Filter() any {
+func (r *executionNotificationReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -314,7 +314,7 @@ func (r *executionReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *executionReceiver) Filter() any {
+func (r *executionReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -361,7 +361,7 @@ func (r *notaryRequestReceiver) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.Comparator interface.
-func (r *notaryRequestReceiver) Filter() any {
+func (r *notaryRequestReceiver) Filter() neorpc.SubscriptionFilter {
 	if r.filter == nil {
 		return nil
 	}
@@ -766,6 +766,11 @@ func (c *WSClient) makeWsRequest(r *neorpc.Request) (*neorpc.Response, error) {
 func (c *WSClient) performSubscription(params []any, rcvr notificationReceiver) (string, error) {
 	var resp string
 
+	if flt := rcvr.Filter(); flt != nil {
+		if err := flt.IsValid(); err != nil {
+			return "", err
+		}
+	}
 	if err := c.performRequest("subscribe", params, &resp); err != nil {
 		return "", err
 	}
@@ -872,11 +877,6 @@ func (c *WSClient) ReceiveExecutions(flt *neorpc.ExecutionFilter, rcvr chan<- *s
 	}
 	params := []any{"transaction_executed"}
 	if flt != nil {
-		if flt.State != nil {
-			if *flt.State != "HALT" && *flt.State != "FAULT" {
-				return "", errors.New("bad state parameter")
-			}
-		}
 		flt = flt.Copy()
 		params = append(params, *flt)
 	}

pkg/rpcclient/wsclient_test.go

@@ -369,7 +369,20 @@ func TestWSExecutionVMStateCheck(t *testing.T) {
 	require.NoError(t, wsc.Init())
 	filter := "NONE"
 	_, err = wsc.ReceiveExecutions(&neorpc.ExecutionFilter{State: &filter}, make(chan *state.AppExecResult))
-	require.Error(t, err)
+	require.ErrorIs(t, err, neorpc.ErrInvalidSubscriptionFilter)
+	wsc.Close()
+}
+
+func TestWSExecutionNotificationNameCheck(t *testing.T) {
+	// Will answer successfully if request slips through.
+	srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "result": "55aaff00"}`)
+	wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
+	require.NoError(t, err)
+	wsc.getNextRequestID = getTestRequestID
+	require.NoError(t, wsc.Init())
+	filter := "notification_from_execution_with_long_name"
+	_, err = wsc.ReceiveExecutionNotifications(&neorpc.NotificationFilter{Name: &filter}, make(chan *state.ContainedNotificationEvent))
+	require.ErrorIs(t, err, neorpc.ErrInvalidSubscriptionFilter)
 	wsc.Close()
 }
 

pkg/services/rpcsrv/server.go

@@ -2729,7 +2729,7 @@ func (s *Server) subscribe(reqParams params.Params, sub *subscriber) (any, *neor
 		return nil, neorpc.WrapErrorWithData(neorpc.ErrInvalidParams, "P2PSigExtensions are disabled")
 	}
 	// Optional filter.
-	var filter any
+	var filter neorpc.SubscriptionFilter
 	if p := reqParams.Value(1); p != nil {
 		param := *p
 		jd := json.NewDecoder(bytes.NewReader(param.RawMessage))
@@ -2754,16 +2754,18 @@ func (s *Server) subscribe(reqParams params.Params, sub *subscriber) (any, *neor
 		case neorpc.ExecutionEventID:
 			flt := new(neorpc.ExecutionFilter)
 			err = jd.Decode(flt)
-			if err == nil && (flt.State == nil || (*flt.State == "HALT" || *flt.State == "FAULT")) {
-				filter = *flt
-			} else if err == nil {
-				err = errors.New("invalid state")
-			}
+			filter = *flt
 		}
 		if err != nil {
 			return nil, neorpc.WrapErrorWithData(neorpc.ErrInvalidParams, err.Error())
 		}
 	}
+	if filter != nil {
+		err = filter.IsValid()
+		if err != nil {
+			return nil, neorpc.WrapErrorWithData(neorpc.ErrInvalidParams, err.Error())
+		}
+	}
 
 	s.subsLock.Lock()
 	var id int

pkg/services/rpcsrv/subscription.go

@@ -28,7 +28,7 @@ type (
 	// feed stores subscriber's desired event ID with filter.
 	feed struct {
 		event  neorpc.EventID
-		filter any
+		filter neorpc.SubscriptionFilter
 	}
 )
 
@@ -38,7 +38,7 @@ func (f feed) EventID() neorpc.EventID {
 }
 
 // Filter implements neorpc.EventComparator interface and returns notification filter.
-func (f feed) Filter() any {
+func (f feed) Filter() neorpc.SubscriptionFilter {
 	return f.filter
 }
 

pkg/services/rpcsrv/subscription_test.go

@@ -676,3 +676,30 @@ func TestSubscriptionOverflow(t *testing.T) {
 	finishedFlag.CompareAndSwap(false, true)
 	c.Close()
 }
+
+func TestFilteredSubscriptions_InvalidFilter(t *testing.T) {
+	var cases = map[string]struct {
+		params string
+	}{
+		"notification with long name": {
+			params: `["notification_from_execution", {"name":"notification_from_execution_with_long_name"}]`,
+		},
+		"execution with invalid vm state": {
+			params: `["transaction_executed", {"state":"NOTHALT"}]`,
+		},
+	}
+	chain, rpcSrv, c, respMsgs, finishedFlag := initCleanServerAndWSClient(t)
+	defer chain.Close()
+	defer rpcSrv.Shutdown()
+
+	for name, this := range cases {
+		t.Run(name, func(t *testing.T) {
+			resp := callWSGetRaw(t, c, fmt.Sprintf(`{"jsonrpc": "2.0","method": "subscribe","params": %s,"id": 1}`, this.params), respMsgs)
+			require.NotNil(t, resp.Error)
+			require.Nil(t, resp.Result)
+			require.Contains(t, resp.Error.Error(), neorpc.ErrInvalidSubscriptionFilter.Error())
+		})
+	}
+	finishedFlag.CompareAndSwap(false, true)
+	c.Close()
+}