From 058f0eec529666ecacd81b63aba586dad0b34a6b Mon Sep 17 00:00:00 2001
From: Han-Wen Nienhuys <hanwen@google.com>
Date: Mon, 14 Apr 2014 09:23:18 -0700
Subject: [PATCH] go.crypto/ssh: only offset channel IDs when debugMux is set.

Otherwise, the package leaks data about total number of
connections established through its channel IDs.

R=agl, jpsugar
CC=golang-codereviews
https://golang.org/cl/87280043
---
 ssh/mux.go | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/ssh/mux.go b/ssh/mux.go
index 5af7c16..321880a 100644
--- a/ssh/mux.go
+++ b/ssh/mux.go
@@ -99,7 +99,8 @@ type mux struct {
 	err     error
 }
 
-// Each new chanList instantiation has a different offset.
+// When debugging, each new chanList instantiation has a different
+// offset.
 var globalOff uint32
 
 func (m *mux) Wait() error {
@@ -120,7 +121,10 @@ func newMux(p packetConn) *mux {
 		incomingRequests: make(chan *Request, 16),
 		errCond:          newCond(),
 	}
-	m.chanList.offset = atomic.AddUint32(&globalOff, 1)
+	if debugMux {
+		m.chanList.offset = atomic.AddUint32(&globalOff, 1)
+	}
+
 	go m.loop()
 	return m
 }