Fix race condition in session maker

cmd/ck-client/ck-client.go

@@ -169,6 +169,7 @@ func main() {
 		}
 		log.Infof("Listening on %v %v for %v client", network, localConfig.LocalAddr, authInfo.ProxyMethod)
 		seshMaker = func() *mux.Session {
+			authInfo := authInfo // copy the struct because we are overwriting SessionId
 			// sessionID is usergenerated. There shouldn't be a security concern because the scope of
 			// sessionID is limited to its UID.
 			quad := make([]byte, 4)

internal/test/integration_test.go

@@ -185,11 +185,9 @@ func establishSession(lcc client.LocalConnConfig, rcc client.RemoteConnConfig, a
 	//									whatever connection initiator (including a proper ck-client)
 
 	netToCkServerD, ckServerListener := connutil.DialerListener(10 * 1024)
-	var sessionCreateMutex sync.Mutex
 
 	clientSeshMaker := func() *mux.Session {
-		sessionCreateMutex.Lock()
-		defer sessionCreateMutex.Unlock()
+		ai := ai
 		quad := make([]byte, 4)
 		common.RandRead(ai.WorldState.Rand, quad)
 		ai.SessionId = binary.BigEndian.Uint32(quad)