From adff4588958fe3ee4970f2bb9849537aca72b904 Mon Sep 17 00:00:00 2001
From: Xiang Li <xiangli.cs@gmail.com>
Date: Thu, 16 Jun 2016 13:42:10 -0700
Subject: [PATCH] etcdserver: fix panic when getting header of raft request

---
 etcdserver/apply_auth.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/etcdserver/apply_auth.go b/etcdserver/apply_auth.go
index 3da6463ac..3f76133ba 100644
--- a/etcdserver/apply_auth.go
+++ b/etcdserver/apply_auth.go
@@ -30,7 +30,12 @@ func newAuthApplierV3(as auth.AuthStore, base applierV3) *authApplierV3 {
 }
 
 func (aa *authApplierV3) Apply(r *pb.InternalRaftRequest) *applyResult {
-	user := r.Header.Username
+	var user string
+	if r.Header != nil {
+		// backward-compatible with pre-3.0 releases when internalRaftRequest
+		// does not have header field
+		user = r.Header.Username
+	}
 	if needAdminPermission(r) && !aa.as.IsAdminPermitted(user) {
 		return &applyResult{err: auth.ErrPermissionDenied}
 	}