server: check the bgp message length before sending

if the length is over 4096, the message will be dropped.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

2 files changed, 14 insertions, 2 deletions

diff --git a/packet/bgp.go b/packet/bgp.go
index aa76cb12..79f62978 100644
--- a/packet/bgp.go
+++ b/packet/bgp.go
@@ -2734,6 +2734,9 @@ func (msg *BGPMessage) Serialize() ([]byte, error) {
 		return nil, err
 	}
 	if msg.Header.Len == 0 {
+		if 19 + len(b) > BGP_MAX_MESSAGE_LENGTH {
+			return nil, NewMessageError(0, 0, nil, fmt.Sprintf("too long message length %d", 19 + len(b)))
+		}
 		msg.Header.Len = 19 + uint16(len(b))
 	}
 	h, err := msg.Header.Serialize()
diff --git a/server/fsm.go b/server/fsm.go
index 4649ef85..f66e8f57 100644
--- a/server/fsm.go
+++ b/server/fsm.go
@@ -567,8 +567,17 @@ func (h *FSMHandler) sendMessageloop() error {
 		// sending notification, we'll die.
 		select {
 		case m := <-h.outgoing:
-			b, _ := m.Serialize()
-			_, err := conn.Write(b)
+			b, err := m.Serialize()
+			if err != nil {
+				log.WithFields(log.Fields{
+					"Topic": "Peer",
+					"Key":   fsm.peerConfig.NeighborAddress,
+					"Data":  err,
+				}).Warn("failed to serialize")
+				fsm.bgpMessageStateUpdate(0, false)
+				continue
+			}
+			_, err = conn.Write(b)
 			if err != nil {
 				h.errorCh <- true
 				return nil