Fix packet handling before init

It caused panic when some kind of packets are arrived
before completing initialization.
Add error check to CookieEcho and Data handlers.

association.go

@@ -1146,6 +1146,11 @@ func (a *Association) handleHeartbeat(c *chunkHeartbeat) []*packet {
 func (a *Association) handleCookieEcho(c *chunkCookieEcho) []*packet {
 	state := a.getState()
 	a.log.Debugf("[%s] COOKIE-ECHO received in state '%s'", a.name, getAssociationStateString(state))
+
+	if a.myCookie == nil {
+		a.log.Debugf("[%s] COOKIE-ECHO received before initialization", a.name)
+		return nil
+	}
 	switch state {
 	default:
 		return nil

association_test.go

@@ -2650,3 +2650,140 @@ func TestAssociation_ShutdownDuringWrite(t *testing.T) {
 		assert.Fail(t, "timed out waiting for a2 read loop to close")
 	}
 }
+
+func TestAssociation_HandlePacketBeforeInit(t *testing.T) {
+	loggerFactory := logging.NewDefaultLoggerFactory()
+
+	testCases := map[string]struct {
+		inputPacket *packet
+	}{
+		"InitAck": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks: []chunk{
+					&chunkInitAck{
+						chunkInitCommon: chunkInitCommon{
+							initiateTag:                    1,
+							numInboundStreams:              1,
+							numOutboundStreams:             1,
+							advertisedReceiverWindowCredit: 1500,
+						},
+					},
+				},
+			},
+		},
+		"Abort": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkAbort{}},
+			},
+		},
+		"CoockeEcho": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkCookieEcho{}},
+			},
+		},
+		"HeartBeat": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkHeartbeat{}},
+			},
+		},
+		"PayloadData": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkPayloadData{}},
+			},
+		},
+		"Sack": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks: []chunk{&chunkSelectiveAck{
+					cumulativeTSNAck:               1000,
+					advertisedReceiverWindowCredit: 1500,
+					gapAckBlocks: []gapAckBlock{
+						{start: 100, end: 200},
+					},
+				}},
+			},
+		},
+		"Reconfig": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks: []chunk{&chunkReconfig{
+					paramA: &paramOutgoingResetRequest{},
+					paramB: &paramReconfigResponse{},
+				}},
+			},
+		},
+		"ForwardTSN": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks: []chunk{&chunkForwardTSN{
+					newCumulativeTSN: 100,
+				}},
+			},
+		},
+		"Error": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkError{}},
+			},
+		},
+		"Shutdown": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkShutdown{}},
+			},
+		},
+		"ShutdownAck": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkShutdownAck{}},
+			},
+		},
+		"ShutdownComplete": {
+			inputPacket: &packet{
+				sourcePort:      1,
+				destinationPort: 1,
+				chunks:          []chunk{&chunkShutdownComplete{}},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			aConn, charlieConn := pipeDump()
+			a := createAssociation(Config{
+				NetConn:              aConn,
+				MaxReceiveBufferSize: 0,
+				LoggerFactory:        loggerFactory,
+			})
+			a.init(true)
+			defer func() {
+				assert.NoError(t, a.close())
+			}()
+
+			packet, err := testCase.inputPacket.marshal()
+			assert.NoError(t, err)
+			_, err = charlieConn.Write(packet)
+			assert.NoError(t, err)
+
+			// Should not panic.
+			time.Sleep(100 * time.Millisecond)
+		})
+	}
+}

chunk_payload_data.go

@@ -2,6 +2,7 @@ package sctp
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"time"
 )
@@ -95,6 +96,8 @@ const (
 	PayloadTypeWebRTCBinaryEmpty PayloadProtocolIdentifier = 57
 )
 
+var errChunkPayloadSmall = errors.New("packet is smaller than the header size")
+
 func (p PayloadProtocolIdentifier) String() string {
 	switch p {
 	case PayloadTypeWebRTCDCEP:
@@ -122,6 +125,9 @@ func (p *chunkPayloadData) unmarshal(raw []byte) error {
 	p.beginningFragment = p.flags&payloadDataBeginingFragmentBitmask != 0
 	p.endingFragment = p.flags&payloadDataEndingFragmentBitmask != 0
 
+	if len(raw) < payloadDataHeaderSize {
+		return errChunkPayloadSmall
+	}
 	p.tsn = binary.BigEndian.Uint32(p.raw[0:])
 	p.streamIdentifier = binary.BigEndian.Uint16(p.raw[4:])
 	p.streamSequenceNumber = binary.BigEndian.Uint16(p.raw[6:])