Verify events hash [Verifiable events part 2]

engine/execution/testutil/fixtures.go

@@ -10,6 +10,8 @@ import (
 
 	"github.com/onflow/cadence"
 	jsoncdc "github.com/onflow/cadence/encoding/json"
+	"github.com/onflow/cadence/runtime"
+	"github.com/onflow/cadence/runtime/interpreter"
 	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/require"
 
@@ -25,17 +27,48 @@ import (
 )
 
 func CreateContractDeploymentTransaction(contractName string, contract string, authorizer flow.Address, chain flow.Chain) *flow.TransactionBody {
+
 	encoded := hex.EncodeToString([]byte(contract))
 
-	return flow.NewTransactionBody().
-		SetScript([]byte(fmt.Sprintf(`transaction {
+	script := []byte(fmt.Sprintf(`transaction {
               prepare(signer: AuthAccount, service: AuthAccount) {
                 signer.contracts.add(name: "%s", code: "%s".decodeHex())
               }
-            }`, contractName, encoded)),
-		).
+            }`, contractName, encoded))
+
+	txBody := flow.NewTransactionBody().
+		SetScript(script).
 		AddAuthorizer(authorizer).
 		AddAuthorizer(chain.ServiceAddress())
+
+	// to synthetically generate event using Cadence code we would need a lot of
+	// copying, so its easier to just hardcode the json string
+	// TODO - extract parts of Cadence to make exporting events easy without interpreter
+
+	interpreterHash := runtime.CodeToHashValue(script)
+	hashElements := interpreterHash.Elements()
+
+	valueStrings := make([]string, len(hashElements))
+
+	for i, value := range hashElements {
+		uint8 := value.(interpreter.UInt8Value)
+		valueStrings[i] = fmt.Sprintf("{\"type\":\"UInt8\",\"value\":\"%d\"}", uint8)
+	}
+
+	//hashValue := strings.Join(valueStrings, ",")
+
+	//payload := fmt.Sprintf("{\"type\":\"Event\",\"value\":{\"id\":\"flow.AccountContractAdded\",\"fields\":[{\"name\":\"address\",\"value\":{\"type\":\"Address\",\"value\":\"%s\"}},{\"name\":\"codeHash\",\"value\":{\"type\":\"Array\",\"value\":[%s]}\"]}},{\"name\":\"contract\",\"value\":{\"type\":\"String\",\"value\":\"%s\"}}]}}",
+	//	authorizer, hashValue, contractName)
+
+	//event := flow.Event{
+	//	Type:             "flow.AccountContractAdded",
+	//	TransactionID:    flow.Identifier{},
+	//	TransactionIndex: 0,
+	//	EventIndex:       0,
+	//	Payload:          []byte(payload),
+	//}
+
+	return txBody
 }
 
 func UpdateContractDeploymentTransaction(contractName string, contract string, authorizer flow.Address, chain flow.Chain) *flow.TransactionBody {

engine/verification/utils/unittest/fixture.go

@@ -185,10 +185,12 @@ func CompleteExecutionReceiptFixture(t *testing.T, chunks int, chain flow.Chain,
 // for that result.
 func ExecutionResultFixture(t *testing.T, chunkCount int, chain flow.Chain, refBlkHeader *flow.Header) (*flow.ExecutionResult,
 	*ExecutionReceiptData) {
+
 	// setups up the first collection of block consists of three transactions
 	tx1 := testutil.DeployCounterContractTransaction(chain.ServiceAddress(), chain)
 	err := testutil.SignTransactionAsServiceAccount(tx1, 0, chain)
 	require.NoError(t, err)
+
 	tx2 := testutil.CreateCounterTransaction(chain.ServiceAddress(), chain.ServiceAddress())
 	err = testutil.SignTransactionAsServiceAccount(tx2, 1, chain)
 	require.NoError(t, err)
@@ -311,14 +313,17 @@ func ExecutionResultFixture(t *testing.T, chunkCount int, chain flow.Chain, refB
 				collectionID = flow.ZeroID
 			}
 
+			eventsHash, err := computationResult.Events[i].Hash()
+			require.NoError(t, err)
+
 			chunk := &flow.Chunk{
 				ChunkBody: flow.ChunkBody{
 					CollectionIndex: uint(i),
 					StartState:      startStateCommitment,
 					// TODO: include real, event collection hash, currently using the collection ID to generate a different Chunk ID
 					// Otherwise, the chances of there being chunks with the same ID before all these TODOs are done is large, since
 					// startState stays the same if blocks are empty
-					EventCollection: collectionID,
+					EventCollection: eventsHash,
 					BlockID:         executableBlock.ID(),
 					// TODO: record gas used
 					TotalComputationUsed: 0,

engine/verification/verifier/engine.go

@@ -205,6 +205,9 @@ func (e *Engine) verify(ctx context.Context, originID flow.Identifier,
 		case *chmodels.CFInvalidVerifiableChunk:
 			// TODO raise challenge
 			e.log.Error().Msg(chFault.String())
+		case *chmodels.CFInvalidEventsCollection:
+			// TODO raise challenge
+			e.log.Error().Msg(chFault.String())
 		default:
 			return engine.NewInvalidInputErrorf("unknown type of chunk fault is received (type: %T) : %v",
 				chFault, chFault.String())

model/chunks/chunkFaults.go

@@ -79,6 +79,35 @@ func NewCFNonMatchingFinalState(expected flow.StateCommitment, computed flow.Sta
 		execResID:  execResID}
 }
 
+// CFInvalidEventsCollection is returned when computed events collection hash is different from the chunk's one
+type CFInvalidEventsCollection struct {
+	expected   flow.Identifier
+	computed   flow.Identifier
+	chunkIndex uint64
+	resultID   flow.Identifier
+}
+
+func NewCFInvalidEventsCollection(expected flow.Identifier, computed flow.Identifier, chInx uint64, execResID flow.Identifier) *CFInvalidEventsCollection {
+	return &CFInvalidEventsCollection{
+		expected:   expected,
+		computed:   computed,
+		chunkIndex: chInx,
+		resultID:   execResID,
+	}
+}
+
+func (c *CFInvalidEventsCollection) ChunkIndex() uint64 {
+	return c.chunkIndex
+}
+
+func (c *CFInvalidEventsCollection) ExecutionResultID() flow.Identifier {
+	return c.resultID
+}
+
+func (c *CFInvalidEventsCollection) String() string {
+	return fmt.Sprintf("events collection hash differs, got %x expected %x for chunk %d with result ID %s", c.computed, c.expected, c.chunkIndex, c.resultID)
+}
+
 // CFInvalidVerifiableChunk is returned when a verifiable chunk is invalid
 // this includes cases that code fails to construct a partial trie,
 // collection hashes doesn't match

module/chunks/chunkVerifier.go

@@ -100,6 +100,8 @@ func (fcv *ChunkVerifier) verifyTransactionsInContext(context fvm.Context, chunk
 		return nil, nil, fmt.Errorf("missing chunk data pack")
 	}
 
+	events := make(flow.EventsList, 0)
+
 	// constructing a partial trie given chunk data package
 	psmt, err := partial.NewLedger(chunkDataPack.Proof, ledger.State(chunkDataPack.StartState), partial.DefaultPathFinderVersion)
 
@@ -166,6 +168,8 @@ func (fcv *ChunkVerifier) verifyTransactionsInContext(context fvm.Context, chunk
 			return nil, nil, fmt.Errorf("failed to execute transaction: %d (%w)", i, err)
 		}
 
+		events = append(events, tx.Events...)
+
 		// always merge back the tx view (fvm is responsible for changes on tx errors)
 		err = chunkView.MergeView(txView)
 		if err != nil {
@@ -182,6 +186,14 @@ func (fcv *ChunkVerifier) verifyTransactionsInContext(context fvm.Context, chunk
 		return nil, chmodels.NewCFMissingRegisterTouch(missingRegs, chIndex, execResID), nil
 	}
 
+	eventsHash, err := events.Hash()
+	if err != nil {
+		return nil, nil, fmt.Errorf("cannot calculate events collection hash: %w", err)
+	}
+	if chunk.EventCollection != eventsHash {
+		return nil, chmodels.NewCFInvalidEventsCollection(chunk.EventCollection, eventsHash, chIndex, execResID), nil
+	}
+
 	// applying chunk delta (register updates at chunk level) to the partial trie
 	// this returns the expected end state commitment after updates and the list of
 	// register keys that was not provided by the chunk data package (err).

module/chunks/chunkVerifier_test.go

@@ -27,6 +27,23 @@ import (
 	"github.com/onflow/flow-go/utils/unittest"
 )
 
+var eventsList = flow.EventsList{
+	{
+		Type:             "event.someType",
+		TransactionID:    flow.Identifier{2, 3, 2, 3},
+		TransactionIndex: 1,
+		EventIndex:       2,
+		Payload:          []byte{7, 3, 1, 2},
+	},
+	{
+		Type:             "event.otherType",
+		TransactionID:    flow.Identifier{3, 3, 3},
+		TransactionIndex: 4,
+		EventIndex:       4,
+		Payload:          []byte{7, 3, 1, 2},
+	},
+}
+
 type ChunkVerifierTestSuite struct {
 	suite.Suite
 	verifier *chunks.ChunkVerifier
@@ -51,7 +68,7 @@ func TestChunkVerifier(t *testing.T) {
 
 // TestHappyPath tests verification of the baseline verifiable chunk
 func (s *ChunkVerifierTestSuite) TestHappyPath() {
-	vch := GetBaselineVerifiableChunk(s.T(), []byte{})
+	vch := GetBaselineVerifiableChunk(s.T(), "")
 	assert.NotNil(s.T(), vch)
 	spockSecret, chFaults, err := s.verifier.Verify(vch)
 	assert.Nil(s.T(), err)
@@ -63,7 +80,7 @@ func (s *ChunkVerifierTestSuite) TestHappyPath() {
 func (s *ChunkVerifierTestSuite) TestMissingRegisterTouchForUpdate() {
 	s.T().Skip("Check new partial ledger for missing keys")
 
-	vch := GetBaselineVerifiableChunk(s.T(), []byte(""))
+	vch := GetBaselineVerifiableChunk(s.T(), "")
 	assert.NotNil(s.T(), vch)
 	// remove the second register touch
 	//vch.ChunkDataPack.RegisterTouches = vch.ChunkDataPack.RegisterTouches[:1]
@@ -78,7 +95,7 @@ func (s *ChunkVerifierTestSuite) TestMissingRegisterTouchForUpdate() {
 // TestMissingRegisterTouchForRead tests verification given a chunkdatapack missing a register touch (read)
 func (s *ChunkVerifierTestSuite) TestMissingRegisterTouchForRead() {
 	s.T().Skip("Check new partial ledger for missing keys")
-	vch := GetBaselineVerifiableChunk(s.T(), []byte(""))
+	vch := GetBaselineVerifiableChunk(s.T(), "")
 	assert.NotNil(s.T(), vch)
 	// remove the second register touch
 	//vch.ChunkDataPack.RegisterTouches = vch.ChunkDataPack.RegisterTouches[1:]
@@ -94,7 +111,7 @@ func (s *ChunkVerifierTestSuite) TestMissingRegisterTouchForRead() {
 // the state commitment computed after updating the partial trie
 // doesn't match the one provided by the chunks
 func (s *ChunkVerifierTestSuite) TestWrongEndState() {
-	vch := GetBaselineVerifiableChunk(s.T(), []byte("wrongEndState"))
+	vch := GetBaselineVerifiableChunk(s.T(), "wrongEndState")
 	assert.NotNil(s.T(), vch)
 	spockSecret, chFaults, err := s.verifier.Verify(vch)
 	assert.Nil(s.T(), err)
@@ -108,14 +125,25 @@ func (s *ChunkVerifierTestSuite) TestWrongEndState() {
 // of failed transaction. if a transaction fails, it should
 // still change the state commitment.
 func (s *ChunkVerifierTestSuite) TestFailedTx() {
-	vch := GetBaselineVerifiableChunk(s.T(), []byte("failedTx"))
+	vch := GetBaselineVerifiableChunk(s.T(), "failedTx")
 	assert.NotNil(s.T(), vch)
 	spockSecret, chFaults, err := s.verifier.Verify(vch)
 	assert.Nil(s.T(), err)
 	assert.Nil(s.T(), chFaults)
 	assert.NotNil(s.T(), spockSecret)
 }
 
+// TestEventsMismatch tests verification behavior in case
+// of emitted events not matching chunks
+func (s *ChunkVerifierTestSuite) TestEventsMismatch() {
+	vch := GetBaselineVerifiableChunk(s.T(), "eventsMismatch")
+	assert.NotNil(s.T(), vch)
+	_, chFault, err := s.verifier.Verify(vch)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), chFault)
+	assert.IsType(s.T(), &chunksmodels.CFInvalidEventsCollection{}, chFault)
+}
+
 // TestVerifyWrongChunkType evaluates that following invocations return an error:
 // - verifying a system chunk with Verify method.
 // - verifying a non-system chunk with SystemChunkVerify method.
@@ -140,11 +168,13 @@ func (s *ChunkVerifierTestSuite) TestVerifyWrongChunkType() {
 // TestEmptyCollection tests verification behaviour if a
 // collection doesn't have any transaction.
 func (s *ChunkVerifierTestSuite) TestEmptyCollection() {
-	vch := GetBaselineVerifiableChunk(s.T(), []byte{})
+	vch := GetBaselineVerifiableChunk(s.T(), "")
 	assert.NotNil(s.T(), vch)
 	col := unittest.CollectionFixture(0)
 	vch.Collection = &col
 	vch.EndState = vch.ChunkDataPack.StartState
+	emptyListHash, _ := flow.EventsList{}.Hash()
+	vch.Chunk.EventCollection = emptyListHash //empty collection emits no events
 	spockSecret, chFaults, err := s.verifier.Verify(vch)
 	assert.Nil(s.T(), err)
 	assert.Nil(s.T(), chFaults)
@@ -154,12 +184,14 @@ func (s *ChunkVerifierTestSuite) TestEmptyCollection() {
 // GetBaselineVerifiableChunk returns a verifiable chunk and sets the script
 // of a transaction in the middle of the collection to some value to signal the
 // mocked vm on what to return as tx exec outcome.
-func GetBaselineVerifiableChunk(t *testing.T, script []byte) *verification.VerifiableChunkData {
+func GetBaselineVerifiableChunk(t *testing.T, script string) *verification.VerifiableChunkData {
 
 	// Collection setup
 
-	coll := unittest.CollectionFixture(5)
-	coll.Transactions[3] = &flow.TransactionBody{Script: script}
+	collectionSize := 5
+	magicTxIndex := 3
+	coll := unittest.CollectionFixture(collectionSize)
+	coll.Transactions[magicTxIndex] = &flow.TransactionBody{Script: []byte(script)}
 
 	guarantee := coll.Guarantee()
 
@@ -228,12 +260,27 @@ func GetBaselineVerifiableChunk(t *testing.T, script []byte) *verification.Verif
 	endState, err := f.Set(update)
 	require.NoError(t, err)
 
+	// events
+	chunkEvents := make(flow.EventsList, 0)
+	for i := 0; i < collectionSize; i++ {
+		if i == magicTxIndex {
+			switch script {
+			case "failedTx":
+				continue
+			}
+		}
+		chunkEvents = append(chunkEvents, eventsList...)
+	}
+	eventsListHash, err := chunkEvents.Hash()
+	require.NoError(t, err)
+
 	// Chunk setup
 	chunk := flow.Chunk{
 		ChunkBody: flow.ChunkBody{
 			CollectionIndex: 0,
 			StartState:      flow.StateCommitment(startState),
 			BlockID:         blockID,
+			EventCollection: eventsListHash,
 		},
 		Index: 0,
 	}
@@ -276,15 +323,25 @@ func (vm *vmMock) Run(ctx fvm.Context, proc fvm.Procedure, led state.View, progr
 		// add updates to the ledger
 		_ = led.Set("00", "", "", []byte{'F'})
 		tx.Logs = []string{"log1", "log2"}
+		tx.Events = eventsList
 	case "failedTx":
 		// add updates to the ledger
 		_ = led.Set("05", "", "", []byte{'B'})
 		tx.Err = &fvmErrors.CadenceRuntimeError{} // inside the runtime (e.g. div by zero, access account)
+	case "eventsMismatch":
+		tx.Events = append(eventsList, flow.Event{
+			Type:             "event.Extra",
+			TransactionID:    flow.Identifier{2, 3},
+			TransactionIndex: 0,
+			EventIndex:       0,
+			Payload:          []byte{88},
+		})
 	default:
 		_, _ = led.Get("00", "", "")
 		_, _ = led.Get("05", "", "")
 		_ = led.Set("05", "", "", []byte{'B'})
 		tx.Logs = []string{"log1", "log2"}
+		tx.Events = eventsList
 	}
 
 	return nil