Prevent potential overflow in timestamp check

Signed-off-by: Yilun <[email protected]>
nknorg · Jan 18, 2019 · b3c7999 · b3c7999
1 parent 03a9f44
commit b3c7999
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/core/ledger/validator.go b/core/ledger/validator.go
@@ -101,13 +101,12 @@ func GetNextBlockSigner(height uint32, timestamp int64) ([]byte, []byte, WinnerT
 		return publicKey, chordID, GenesisSigner, nil
 	}
 
-	// calculate time difference
-	timeSinceLastBlock := timestamp - header.Timestamp
-
-	if timeSinceLastBlock <= 0 {
+	if timestamp <= header.Timestamp {
 		return nil, nil, 0, fmt.Errorf("timestamp %d is earlier than previous block timestamp %d", timestamp, header.Timestamp)
 	}
 
+	// calculate time difference
+	timeSinceLastBlock := timestamp - header.Timestamp
 	timeSlot := int64(config.ProposerChangeTime / time.Second)
 
 	if timeSinceLastBlock >= timeSlot {