From 9fea9cf6580751b513340b48e8138affff3dea16 Mon Sep 17 00:00:00 2001
From: Daniel Oaks <daniel@danieloaks.net>
Date: Thu, 3 Nov 2016 16:59:57 +1000
Subject: [PATCH] modes: Restrict changing modes correctly

---
 CHANGELOG.md |  1 +
 irc/modes.go | 18 +++++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 375e8968..9dc09342 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ New release of Oragono!
 * Fixed bug where `HELP` wouldn't correctly display for operators, and added more help topics.
 * Fixed display of large `MONITOR` lists.
 * Fixed bug where you would always have certain capabilities enabled.
+* Fixed being able to change modes when not an operator.
 
 
 ## [0.3.0] - 2016-10-23
diff --git a/irc/modes.go b/irc/modes.go
index 8baf51af..246e0c84 100644
--- a/irc/modes.go
+++ b/irc/modes.go
@@ -409,7 +409,20 @@ func cmodeHandler(server *Server, client *Client, msg ircmsg.IrcMessage) bool {
 		// so we only output one warning for each list type when full
 		listFullWarned := make(map[ChannelMode]bool)
 
+		clientIsOp := channel.ClientIsAtLeast(client, ChannelOperator)
+		var alreadySentPrivError bool
+
 		for _, change := range changes {
+			// chan priv modes are checked specially so ignore them
+			// means regular users can't view ban/except lists... but I'm not worried about that
+			if ChannelModePrefixes[change.mode] == "" && !clientIsOp {
+				if !alreadySentPrivError {
+					alreadySentPrivError = true
+					client.Send(nil, client.server.name, ERR_CHANOPRIVSNEEDED, channel.name, "You're not a channel operator")
+				}
+				continue
+			}
+
 			switch change.mode {
 			case BanMask, ExceptMask, InviteMask:
 				mask := change.arg
@@ -519,7 +532,10 @@ func cmodeHandler(server *Server, client *Client, msg ircmsg.IrcMessage) bool {
 					if change.op == Remove && casefoldedName == client.nickCasefolded {
 						// success!
 					} else {
-						client.Send(nil, client.server.name, ERR_CHANOPRIVSNEEDED, channel.name, "You're not a channel operator")
+						if !alreadySentPrivError {
+							alreadySentPrivError = true
+							client.Send(nil, client.server.name, ERR_CHANOPRIVSNEEDED, channel.name, "You're not a channel operator")
+						}
 						continue
 					}
 				}