fix: guard possible nil panics

Signed-off-by: Chris Gianelloni <[email protected]>

Author: wolf31o2

cmd/gouroboros/chainsync.go

@@ -170,7 +170,7 @@ func testChainSync(f *globalFlags) {
 			os.Exit(1)
 		}
 	}()
-	oConn, err = ouroboros.New(
+	o, err := ouroboros.New(
 		ouroboros.WithConnection(conn),
 		ouroboros.WithNetworkMagic(uint32(f.networkMagic)),
 		ouroboros.WithErrorChan(errorChan),
@@ -183,6 +183,11 @@ func testChainSync(f *globalFlags) {
 		fmt.Printf("ERROR: %s\n", err)
 		os.Exit(1)
 	}
+	if o == nil {
+		fmt.Println("ERROR: empty connection")
+		os.Exit(1)
+	}
+	oConn = o
 
 	var point common.Point
 	if chainSyncFlags.tip {
@@ -260,6 +265,9 @@ func chainSyncRollForwardHandler(
 		blockSlot := v.SlotNumber()
 		blockHash, _ := hex.DecodeString(v.Hash())
 		var err error
+		if oConn == nil {
+			return fmt.Errorf("empty ouroboros connection, aborting!")
+		}
 		block, err = oConn.BlockFetch().Client.GetBlock(common.NewPoint(blockSlot, blockHash))
 		if err != nil {
 			return err

ledger/verify_block.go

@@ -52,6 +52,11 @@ func VerifyBlock(block BlockHexCbor) (error, bool, string, uint64, uint64) {
 			headerUnmarshalError.Error(),
 		), false, "", 0, 0
 	}
+	if header == nil {
+		return fmt.Errorf(
+			"VerifyBlock: header returned empty",
+		), false, "", 0, 0
+	}
 	isKesValid, errKes := VerifyKes(header, slotPerKesPeriod)
 	if errKes != nil {
 		return fmt.Errorf(

protocol/handshake/server.go

@@ -129,6 +129,21 @@ func (s *Server) handleProposeVersions(msg protocol.Message) error {
 	// Decode protocol parameters for selected version
 	versionInfo := protocol.GetProtocolVersion(proposedVersion)
 	versionData := s.config.ProtocolVersionMap[proposedVersion]
+	if versionData == nil {
+		msgRefuse := NewMsgRefuse(
+			[]any{
+				RefuseReasonDecodeError,
+				proposedVersion,
+				fmt.Errorf("handshake failed: refused due to empty version data"),
+			},
+		)
+		if err := s.SendMessage(msgRefuse); err != nil {
+			return err
+		}
+		return fmt.Errorf(
+			"handshake failed: refused due to empty version data",
+		)
+	}
 	proposedVersionData, err := versionInfo.NewVersionDataFromCborFunc(
 		msgProposeVersions.VersionMap[proposedVersion],
 	)
@@ -148,6 +163,22 @@ func (s *Server) handleProposeVersions(msg protocol.Message) error {
 			err,
 		)
 	}
+	if proposedVersionData == nil {
+		msgRefuse := NewMsgRefuse(
+			[]any{
+				RefuseReasonDecodeError,
+				proposedVersion,
+				fmt.Errorf("handshake failed: refused due to empty version map"),
+			},
+		)
+		if err := s.SendMessage(msgRefuse); err != nil {
+			return err
+		}
+		return fmt.Errorf(
+			"handshake failed: refused due to empty version map",
+		)
+	}
+
 	// Check network magic
 	if proposedVersionData.NetworkMagic() != versionData.NetworkMagic() {
 		errMsg := fmt.Sprintf(