Improved request account validation

Signed-off-by: Neil Twigg <neil@nats.io>

Author: neilalexander

server/jetstream_api.go

@@ -2526,6 +2526,9 @@ func (s *Server) jsLeaderServerRemoveRequest(sub *subscription, c *client, _ *Ac
 		s.Warnf(badAPIRequestT, msg)
 		return
 	}
+	if acc != s.SystemAccount() {
+		return
+	}
 
 	js, cc := s.getJetStreamCluster()
 	if js == nil || cc == nil || cc.meta == nil {
@@ -2650,6 +2653,10 @@ func (s *Server) jsLeaderServerStreamMoveRequest(sub *subscription, c *client, _
 	accName := tokenAt(subject, 6)
 	streamName := tokenAt(subject, 7)
 
+	if acc.GetName() != accName && acc != s.SystemAccount() {
+		return
+	}
+
 	var resp = JSApiStreamUpdateResponse{ApiResponse: ApiResponse{Type: JSApiStreamUpdateResponseType}}
 
 	var req JSApiMetaServerStreamMoveRequest
@@ -2807,6 +2814,10 @@ func (s *Server) jsLeaderServerStreamCancelMoveRequest(sub *subscription, c *cli
 	accName := tokenAt(subject, 6)
 	streamName := tokenAt(subject, 7)
 
+	if acc.GetName() != accName && acc != s.SystemAccount() {
+		return
+	}
+
 	targetAcc, ok := s.accounts.Load(accName)
 	if !ok {
 		resp.Error = NewJSNoAccountError()
@@ -2893,6 +2904,9 @@ func (s *Server) jsLeaderAccountPurgeRequest(sub *subscription, c *client, _ *Ac
 		s.Warnf(badAPIRequestT, msg)
 		return
 	}
+	if acc != s.SystemAccount() {
+		return
+	}
 
 	js := s.getJetStream()
 	if js == nil {