From 779c91745045007697d547f3b03e712316877e8a Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Sun, 13 Sep 2020 23:15:36 +0700
Subject: [PATCH] fix race condition in handshake fuzz code

---
 fuzzing/handshake/fuzz.go | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fuzzing/handshake/fuzz.go b/fuzzing/handshake/fuzz.go
index 0cd15cc7..3f1e8695 100644
--- a/fuzzing/handshake/fuzz.go
+++ b/fuzzing/handshake/fuzz.go
@@ -11,6 +11,7 @@ import (
 	"log"
 	"math"
 	mrand "math/rand"
+	"sync"
 	"time"
 
 	"github.com/lucas-clemente/quic-go/fuzzing/internal/helper"
@@ -159,6 +160,7 @@ type handshakeRunner interface {
 }
 
 type runner struct {
+	sync.Mutex
 	errored        bool
 	client, server *handshake.CryptoSetup
 }
@@ -172,6 +174,8 @@ func newRunner(client, server *handshake.CryptoSetup) *runner {
 func (r *runner) OnReceivedParams(*wire.TransportParameters) {}
 func (r *runner) OnHandshakeComplete()                       {}
 func (r *runner) OnError(err error) {
+	r.Lock()
+	defer r.Unlock()
 	if r.errored {
 		return
 	}
@@ -179,6 +183,11 @@ func (r *runner) OnError(err error) {
 	(*r.client).Close()
 	(*r.server).Close()
 }
+func (r *runner) Errored() bool {
+	r.Lock()
+	defer r.Unlock()
+	return r.errored
+}
 func (r *runner) DropKeys(protocol.EncryptionLevel) {}
 
 const alpn = "fuzzing"
@@ -435,7 +444,7 @@ messageLoop:
 		case <-done: // test done
 			break messageLoop
 		}
-		if runner.errored {
+		if runner.Errored() {
 			break messageLoop
 		}
 	}
@@ -443,7 +452,7 @@ messageLoop:
 	<-done
 	_ = client.ConnectionState()
 	_ = server.ConnectionState()
-	if runner.errored {
+	if runner.Errored() {
 		return 0
 	}