Reject watch request with -1 revision and make rangeEvents safe against negative revision

Signed-off-by: Marek Siarkowicz <[email protected]>

Author: serathius

server/etcdserver/api/v3rpc/watch.go

@@ -272,6 +272,22 @@ func (sws *serverWatchStream) recvLoop() error {
 				// support  >= key queries
 				creq.RangeEnd = []byte{}
 			}
+			if creq.StartRevision < 0 {
+				wr := &pb.WatchResponse{
+					Header:       sws.newResponseHeader(sws.watchStream.Rev()),
+					WatchId:      clientv3.InvalidWatchID,
+					Canceled:     true,
+					Created:      true,
+					CancelReason: rpctypes.ErrCompacted.Error(),
+				}
+
+				select {
+				case sws.ctrlStream <- wr:
+					continue
+				case <-sws.closec:
+					return nil
+				}
+			}
 
 			err := sws.isWatchPermitted(creq)
 			if err != nil {

server/storage/mvcc/watchable_store.go

@@ -447,6 +447,9 @@ func rangeEventsWithReuse(lg *zap.Logger, b backend.Backend, evs []mvccpb.Event,
 
 // rangeEvents returns events in range [minRev, maxRev).
 func rangeEvents(lg *zap.Logger, b backend.Backend, minRev, maxRev int64) []mvccpb.Event {
+	if minRev < 0 {
+		minRev = 0
+	}
 	minBytes, maxBytes := NewRevBytes(), NewRevBytes()
 	minBytes = RevToBytes(Revision{Main: minRev}, minBytes)
 	maxBytes = RevToBytes(Revision{Main: maxRev}, maxBytes)

server/storage/mvcc/watchable_store_test.go

@@ -405,13 +405,14 @@ func TestRangeEvents(t *testing.T) {
 		expectEvents []mvccpb.Event
 	}{
 		// maxRev, top to bottom
-		{minRev: 2, maxRev: 6, expectEvents: expectEvents[0:5]},
-		{minRev: 2, maxRev: 5, expectEvents: expectEvents[0:3]},
-		{minRev: 2, maxRev: 4, expectEvents: expectEvents[0:2]},
-		{minRev: 2, maxRev: 3, expectEvents: expectEvents[0:1]},
-		{minRev: 2, maxRev: 2, expectEvents: expectEvents[0:0]},
+		{minRev: -1, maxRev: 6, expectEvents: expectEvents[0:5]},
+		{minRev: -1, maxRev: 5, expectEvents: expectEvents[0:3]},
+		{minRev: -1, maxRev: 4, expectEvents: expectEvents[0:2]},
+		{minRev: -1, maxRev: 3, expectEvents: expectEvents[0:1]},
+		{minRev: -1, maxRev: 2, expectEvents: expectEvents[0:0]},
 
 		// minRev, bottom to top
+		{minRev: -1, maxRev: 6, expectEvents: expectEvents[0:5]},
 		{minRev: 2, maxRev: 6, expectEvents: expectEvents[0:5]},
 		{minRev: 3, maxRev: 6, expectEvents: expectEvents[1:5]},
 		{minRev: 4, maxRev: 6, expectEvents: expectEvents[2:5]},