From ae194c147024466f729cbcc2bf035d224fe3a198 Mon Sep 17 00:00:00 2001
From: "J. David Lowe" <j.david.lowe@gmail.com>
Date: Fri, 4 Jun 2021 08:15:34 -0700
Subject: [PATCH] etcdserver: don't activate alarm w/missing AlarmType

Narrowly prevent etcd from crashing when given a bad ACTIVATE payload, e.g.:

$ curl -d "{\"action\":\"ACTIVATE\"}" ${ETCD}/v3/maintenance/alarm
curl: (52) Empty reply from server
---
 server/etcdserver/apply.go |  5 ++++-
 tests/e2e/v3_curl_test.go  | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/server/etcdserver/apply.go b/server/etcdserver/apply.go
index cf281d1a9c7..5a77ef37734 100644
--- a/server/etcdserver/apply.go
+++ b/server/etcdserver/apply.go
@@ -721,6 +721,9 @@ func (a *applierV3backend) Alarm(ar *pb.AlarmRequest) (*pb.AlarmResponse, error)
 	case pb.AlarmRequest_GET:
 		resp.Alarms = a.s.alarmStore.Get(ar.Alarm)
 	case pb.AlarmRequest_ACTIVATE:
+		if ar.Alarm == pb.AlarmType_NONE {
+			break
+		}
 		m := a.s.alarmStore.Activate(types.ID(ar.MemberID), ar.Alarm)
 		if m == nil {
 			break
@@ -738,7 +741,7 @@ func (a *applierV3backend) Alarm(ar *pb.AlarmRequest) (*pb.AlarmResponse, error)
 		case pb.AlarmType_NOSPACE:
 			a.s.applyV3 = newApplierV3Capped(a)
 		default:
-			lg.Warn("unimplemented alarm activation", zap.String("alarm", fmt.Sprintf("%+v", m)))
+			lg.Panic("unimplemented alarm activation", zap.String("alarm", fmt.Sprintf("%+v", m)))
 		}
 	case pb.AlarmRequest_DEACTIVATE:
 		m := a.s.alarmStore.Deactivate(types.ID(ar.MemberID), ar.Alarm)
diff --git a/tests/e2e/v3_curl_test.go b/tests/e2e/v3_curl_test.go
index ecc94888d14..7c697115057 100644
--- a/tests/e2e/v3_curl_test.go
+++ b/tests/e2e/v3_curl_test.go
@@ -366,6 +366,21 @@ func testV3CurlResignMissiongLeaderKey(cx ctlCtx) {
 	}
 }
 
+func TestV3CurlMaintenanceAlarmMissiongAlarm(t *testing.T) {
+	for _, p := range apiPrefix {
+		testCtl(t, testV3CurlMaintenanceAlarmMissiongAlarm, withApiPrefix(p), withCfg(*newConfigNoTLS()))
+	}
+}
+
+func testV3CurlMaintenanceAlarmMissiongAlarm(cx ctlCtx) {
+	if err := cURLPost(cx.epc, cURLReq{
+		endpoint: path.Join(cx.apiPrefix, "/maintenance/alarm"),
+		value:    `{"action": "ACTIVATE"}`,
+	}); err != nil {
+		cx.t.Fatalf("failed post maintenance alarm (%s) (%v)", cx.apiPrefix, err)
+	}
+}
+
 // to manually decode; JSON marshals integer fields with
 // string types, so can't unmarshal with epb.CampaignResponse
 type campaignResponse struct {