diff --git a/handshake_messages.go b/handshake_messages.go
index b794f05..799a776 100644
--- a/handshake_messages.go
+++ b/handshake_messages.go
@@ -367,12 +367,16 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool {
 
 		switch extension {
 		case extensionServerName:
-			if length < 2 {
+			d := data[:length]
+			if len(d) < 2 {
 				return false
 			}
-			numNames := int(data[0])<<8 | int(data[1])
-			d := data[2:]
-			for i := 0; i < numNames; i++ {
+			namesLen := int(d[0])<<8 | int(d[1])
+			d = d[2:]
+			if len(d) != namesLen {
+				return false
+			}
+			for len(d) > 0 {
 				if len(d) < 3 {
 					return false
 				}
@@ -383,7 +387,7 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool {
 					return false
 				}
 				if nameType == 0 {
-					m.serverName = string(d[0:nameLen])
+					m.serverName = string(d[:nameLen])
 					break
 				}
 				d = d[nameLen:]