There were situations where invalid subjects could be assigned to streams.

server/jetstream.go

@@ -1115,6 +1115,34 @@ func (a *Account) EnableJetStream(limits *JetStreamAccountLimits) error {
 				s.Warnf("  Error adding stream %q to template %q: %v", cfg.Name, cfg.Template, err)
 			}
 		}
+
+		// We had a bug that could allow subjects in that had prefix or suffix spaces. We check for that here
+		// and will patch them on the fly for now. We will warn about them.
+		var hadSubjErr bool
+		for i, subj := range cfg.StreamConfig.Subjects {
+			if !IsValidSubject(subj) {
+				s.Warnf("  Detected bad subject %q while adding stream %q, will attempt to repair", subj, cfg.Name)
+				if nsubj := strings.TrimSpace(subj); IsValidSubject(nsubj) {
+					s.Warnf("  Bad subject %q repaired to %q", subj, nsubj)
+					cfg.StreamConfig.Subjects[i] = nsubj
+				} else {
+					s.Warnf("  Error recreating stream %q: %v", cfg.Name, "invalid subject")
+					hadSubjErr = true
+					break
+				}
+			}
+		}
+		if hadSubjErr {
+			continue
+		}
+
+		// The other possible bug is assigning subjects to mirrors, so check for that and patch as well.
+		if cfg.StreamConfig.Mirror != nil && len(cfg.StreamConfig.Subjects) > 0 {
+			s.Warnf("  Detected subjects on a mirrored stream %q, will remove", cfg.Name)
+			cfg.StreamConfig.Subjects = nil
+		}
+
+		// Add in the stream.
 		mset, err := a.addStream(&cfg.StreamConfig)
 		if err != nil {
 			s.Warnf("  Error recreating stream %q: %v", cfg.Name, err)

server/jetstream_test.go

@@ -13700,6 +13700,85 @@ func TestJetStreamMemoryCorruption(t *testing.T) {
 	}
 }
 
+func TestJetStreamRecoverBadStreamSubjects(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	config := s.JetStreamConfig()
+	if config != nil {
+		defer removeDir(t, config.StoreDir)
+	}
+	sd := config.StoreDir
+	s.Shutdown()
+
+	f := path.Join(sd, "$G", "streams", "TEST")
+	fs, err := newFileStore(FileStoreConfig{StoreDir: f}, StreamConfig{
+		Name:     "TEST",
+		Subjects: []string{"foo", "bar", " baz "}, // baz has spaces
+		Storage:  FileStorage,
+	})
+	require_NoError(t, err)
+	fs.Stop()
+
+	s = RunJetStreamServerOnPort(-1, sd)
+	defer s.Shutdown()
+
+	nc, js := jsClientConnect(t, s)
+	defer nc.Close()
+
+	si, err := js.StreamInfo("TEST")
+	require_NoError(t, err)
+
+	if len(si.Config.Subjects) != 3 {
+		t.Fatalf("Expected to recover all subjects")
+	}
+}
+
+func TestJetStreamRecoverBadMirrorConfigWithSubjects(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	defer s.Shutdown()
+
+	config := s.JetStreamConfig()
+	if config != nil {
+		defer removeDir(t, config.StoreDir)
+	}
+	sd := config.StoreDir
+
+	// Client for API requests.
+	nc, js := jsClientConnect(t, s)
+	defer nc.Close()
+
+	// Origin
+	_, err := js.AddStream(&nats.StreamConfig{
+		Name:     "S",
+		Subjects: []string{"foo"},
+	})
+	require_NoError(t, err)
+
+	s.Shutdown()
+
+	f := path.Join(sd, "$G", "streams", "M")
+	fs, err := newFileStore(FileStoreConfig{StoreDir: f}, StreamConfig{
+		Name:     "M",
+		Subjects: []string{"foo", "bar", "baz"}, // Mirrors should not have spaces.
+		Mirror:   &StreamSource{Name: "S"},
+		Storage:  FileStorage,
+	})
+	require_NoError(t, err)
+	fs.Stop()
+
+	s = RunJetStreamServerOnPort(-1, sd)
+	defer s.Shutdown()
+
+	nc, js = jsClientConnect(t, s)
+	defer nc.Close()
+
+	si, err := js.StreamInfo("M")
+	require_NoError(t, err)
+
+	if len(si.Config.Subjects) != 0 {
+		t.Fatalf("Expected to have NO subjects on mirror")
+	}
+}
+
 ///////////////////////////////////////////////////////////////////////////
 // Simple JetStream Benchmarks
 ///////////////////////////////////////////////////////////////////////////

server/stream.go

@@ -886,11 +886,11 @@ func checkStreamCfg(config *StreamConfig) (StreamConfig, error) {
 			if subjectIsSubsetMatch(subj, "$JS.API.>") {
 				return StreamConfig{}, fmt.Errorf("subjects overlap with jetstream api")
 			}
-
+			// Make sure the subject is valid.
 			if !IsValidSubject(subj) {
 				return StreamConfig{}, fmt.Errorf("invalid subject")
 			}
-
+			// Mark for duplicate check.
 			dset[subj] = struct{}{}
 		}
 	}