webrtc: fix deprecated webrtcICEServers parser for IPv6 hosts; (#5932)

strings.Split produces wrong part count when the host contains colons
(IPv6). SplitN(s, ";", 4) keeps the hostport token intact.

---------

Co-authored-by: aler9 <46489434+aler9@users.noreply.github.com>

internal/conf/conf.go

@@ -986,10 +986,11 @@ func (conf *Conf) Validate(l logger.Writer) error {
 			"and has been replaced with 'webrtcICEServers2'")
 
 		for _, server := range *conf.WebRTCICEServers {
-			parts := strings.Split(server, ":")
-			if len(parts) == 5 {
+			// old format: scheme:username:password:hostport; SplitN avoids splitting IPv6 colons
+			parts := strings.SplitN(server, ":", 4)
+			if len(parts) == 4 {
 				conf.WebRTCICEServers2 = append(conf.WebRTCICEServers2, WebRTCICEServer{
-					URL:      parts[0] + ":" + parts[3] + ":" + parts[4],
+					URL:      parts[0] + ":" + parts[3],
 					Username: parts[1],
 					Password: parts[2],
 				})

internal/conf/conf_test.go

@@ -343,6 +343,21 @@ func TestConfDeprecatedAuth(t *testing.T) {
 	}, conf.AuthInternalUsers)
 }
 
+func TestConfDeprecatedWebRTCICEServersIPv6(t *testing.T) {
+	tmpf := createTempFile(t, []byte(
+		"webrtcICEServers:\n"+
+			"- \"turn:myuser:mypass:[2001:db8::1]:3478?transport=tcp\"\n"))
+
+	conf, _, err := Load(tmpf, nil, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, []WebRTCICEServer{{
+		URL:      "turn:[2001:db8::1]:3478?transport=tcp",
+		Username: "myuser",
+		Password: "mypass",
+	}}, conf.WebRTCICEServers2)
+}
+
 func TestConfErrors(t *testing.T) {
 	for _, ca := range []struct {
 		name string