getHeader: verify that pubkey in message is the relay-key we trust (f…

…lashbots#239)

server/mock_relay.go

@@ -17,6 +17,14 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+var (
+	mockRelaySecretKeyHex = "0x4e343a647c5a5c44d76c2c58b63f02cdf3a9a0ec40f102ebc26363b4b1b95033"
+	// mockRelayPublicKeyHex = "0x8a1d7b8dd64e0aafe7ea7b6c95065c9364cf99d38470c12ee807d55f7de1529ad29ce2c422e0b65e3d5a05c02caca249"
+	skBytes, _            = hexutil.Decode(mockRelaySecretKeyHex)
+	mockRelaySecretKey, _ = bls.SecretKeyFromBytes(skBytes[:])
+	mockRelayPublicKey    = bls.PublicKeyFromSecretKey(mockRelaySecretKey)
+)
+
 // mockRelay is used to fake a relay's behavior.
 // You can override each of its handler by setting the instance's HandlerOverride_METHOD_TO_OVERRIDE to your own
 // handler.
@@ -49,17 +57,16 @@ type mockRelay struct {
 
 // newMockRelay creates a mocked relay which implements the backend.BoostBackend interface
 // A secret key must be provided to sign default and custom response messages
-func newMockRelay(t *testing.T, secretKey *bls.SecretKey) *mockRelay {
-	publicKey := bls.PublicKeyFromSecretKey(secretKey)
-	relay := &mockRelay{t: t, secretKey: secretKey, publicKey: publicKey, requestCount: make(map[string]int)}
+func newMockRelay(t *testing.T) *mockRelay {
+	relay := &mockRelay{t: t, secretKey: mockRelaySecretKey, publicKey: mockRelayPublicKey, requestCount: make(map[string]int)}
 
 	// Initialize server
 	relay.Server = httptest.NewServer(relay.getRouter())
 
 	// Create the RelayEntry with correct pubkey
 	url, err := url.Parse(relay.Server.URL)
 	require.NoError(t, err)
-	urlWithKey := fmt.Sprintf("%s://%s@%s", url.Scheme, hexutil.Encode(publicKey.Compress()), url.Host)
+	urlWithKey := fmt.Sprintf("%s://%s@%s", url.Scheme, hexutil.Encode(mockRelayPublicKey.Compress()), url.Host)
 	relay.RelayEntry, err = NewRelayEntry(urlWithKey)
 	require.NoError(t, err)
 	return relay

server/mock_relay_test.go

@@ -2,19 +2,16 @@ package server
 
 import (
 	"bytes"
-	"github.com/flashbots/go-boost-utils/bls"
-	"github.com/stretchr/testify/require"
 	"net/http"
 	"net/http/httptest"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func Test_mockRelay(t *testing.T) {
 	t.Run("bad payload", func(t *testing.T) {
-		privateKey, _, err := bls.GenerateNewKeypair()
-		require.NoError(t, err)
-
-		relay := newMockRelay(t, privateKey)
+		relay := newMockRelay(t)
 		req, err := http.NewRequest("POST", pathRegisterValidator, bytes.NewReader([]byte("123")))
 		require.NoError(t, err)
 		rr := httptest.NewRecorder()

server/service.go

@@ -326,6 +326,11 @@ func (m *BoostService) handleGetHeader(w http.ResponseWriter, req *http.Request)
 				"value":       responsePayload.Data.Message.Value.String(),
 			})
 
+			if relay.PublicKey != responsePayload.Data.Message.Pubkey {
+				log.Errorf("bid pubkey mismatch. expected: %s - got: %s", relay.PublicKey.String(), responsePayload.Data.Message.Pubkey.String())
+				return
+			}
+
 			// Verify the relay signature in the relay response
 			ok, err := types.VerifySignature(responsePayload.Data.Message, m.builderSigningDomain, relay.PublicKey[:], responsePayload.Data.Signature[:])
 			if err != nil {

server/service_test.go

@@ -13,8 +13,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/flashbots/go-boost-utils/bls"
-
 	"github.com/flashbots/go-boost-utils/types"
 	"github.com/stretchr/testify/require"
 )
@@ -32,12 +30,8 @@ func newTestBackend(t *testing.T, numRelays int, relayTimeout time.Duration) *te
 
 	relayEntries := make([]RelayEntry, numRelays)
 	for i := 0; i < numRelays; i++ {
-		// Generate private key for relay
-		blsPrivateKey, _, err := bls.GenerateNewKeypair()
-		require.NoError(t, err)
-
 		// Create a mock relay
-		backend.relays[i] = newMockRelay(t, blsPrivateKey)
+		backend.relays[i] = newMockRelay(t)
 		relayEntries[i] = backend.relays[i].RelayEntry
 	}