From 8e0c256c472f6cb80b66159fc3a4aa63b532ee95 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Thu, 25 Apr 2024 20:06:13 +0200
Subject: [PATCH] upstream: fix panic on malformed RPL_CHANNELMODEIS

---
 upstream.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/upstream.go b/upstream.go
index ca17ea8..f04fb8c 100644
--- a/upstream.go
+++ b/upstream.go
@@ -1389,8 +1389,10 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 			return err
 		}
 		modeStr := ""
+		var modeArgs []string
 		if len(msg.Params) > 2 {
 			modeStr = msg.Params[2]
+			modeArgs = msg.Params[3:]
 		}
 
 		ch := uc.channels.Get(channel)
@@ -1401,7 +1403,7 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 
 		firstMode := ch.modes == nil
 		ch.modes = make(map[byte]string)
-		if err := applyChannelModes(ch, modeStr, msg.Params[3:]); err != nil {
+		if err := applyChannelModes(ch, modeStr, modeArgs); err != nil {
 			return err
 		}