Read admin lookup maps under client lock

admin.go

@@ -83,7 +83,9 @@ func (b *Barnard) OpenAdminMenu() {
 	if b.adminTargetChan != nil {
 		b.adminTargetChan.RequestPermission()
 	}
-	if root := b.Client.Channels[0]; root != nil && root != b.adminTargetChan {
+	var root *gumble.Channel
+	b.Client.Do(func() { root = b.Client.Channels[0] })
+	if root != nil && root != b.adminTargetChan {
 		root.RequestPermission()
 	}
 	b.UiAdmin.Rebuild()
@@ -964,39 +966,47 @@ func (b *Barnard) findOrCreateACLRule(subjectType, subject string) *gumble.ACLRu
 	}
 }
 
-func (b *Barnard) findUser(token string) *gumble.User {
+func (b *Barnard) findUser(token string) (found *gumble.User) {
 	if b.Client == nil {
 		return nil
 	}
-	if session, err := strconv.ParseUint(token, 10, 32); err == nil {
+	b.Client.Do(func() {
-		if user := b.Client.Users[uint32(session)]; user != nil {
+		if session, err := strconv.ParseUint(token, 10, 32); err == nil {
-			return user
+			found = b.Client.Users[uint32(session)]
+			if found != nil {
+				return
+			}
 		}
-	}
+		for _, user := range b.Client.Users {
-	for _, user := range b.Client.Users {
+			if strings.EqualFold(user.Name, token) {
-		if strings.EqualFold(user.Name, token) {
+				found = user
-			return user
+				return
+			}
 		}
-	}
+	})
-	return nil
+	return found
 }
 
-func (b *Barnard) findChannel(token string) *gumble.Channel {
+func (b *Barnard) findChannel(token string) (found *gumble.Channel) {
 	if b.Client == nil {
 		return nil
 	}
 	token = strings.TrimSpace(token)
-	if id, err := strconv.ParseUint(token, 10, 32); err == nil {
+	b.Client.Do(func() {
-		if channel := b.Client.Channels[uint32(id)]; channel != nil {
+		if id, err := strconv.ParseUint(token, 10, 32); err == nil {
-			return channel
+			found = b.Client.Channels[uint32(id)]
+			if found != nil {
+				return
+			}
 		}
-	}
+		for _, channel := range b.Client.Channels {
-	for _, channel := range b.Client.Channels {
+			if strings.EqualFold(channel.Name, token) {
-		if strings.EqualFold(channel.Name, token) {
+				found = channel
-			return channel
+				return
+			}
 		}
-	}
+	})
-	return nil
+	return found
 }
 
 func (b *Barnard) findRegisteredUser(token string) *gumble.RegisteredUser {
@@ -1019,7 +1029,9 @@ func (b *Barnard) adminCanRoot(permission gumble.Permission) bool {
 	if b.Client == nil {
 		return true
 	}
-	return b.adminCanChannel(b.Client.Channels[0], permission)
+	var root *gumble.Channel
+	b.Client.Do(func() { root = b.Client.Channels[0] })
+	return b.adminCanChannel(root, permission)
 }
 
 func (b *Barnard) adminCanChannel(channel *gumble.Channel, permission gumble.Permission) bool {

admin_test.go

@@ -7,6 +7,20 @@ import (
 	"git.stormux.org/storm/barnard/uiterm"
 )
 
+// Regression: admin lookup helpers read Client.Users and Client.Channels while
+// TCP handlers could mutate those maps.
+func TestAdminLookupUsesClientSnapshot(t *testing.T) {
+	user := &gumble.User{Session: 7, Name: "Guest"}
+	channel := &gumble.Channel{ID: 4, Name: "Room"}
+	b := &Barnard{Client: &gumble.Client{Users: gumble.Users{7: user}, Channels: gumble.Channels{4: channel}}}
+	if b.findUser("guest") != user || b.findUser("7") != user {
+		t.Fatal("user lookup failed")
+	}
+	if b.findChannel("room") != channel || b.findChannel("4") != channel {
+		t.Fatal("channel lookup failed")
+	}
+}
+
 func TestParseToggleState(t *testing.T) {
 	tests := []struct {
 		name    string