evidence: retrieve header at height of evidence for validation (#4870)

validation of lunatic evidence requires that the node retrieve the header at the height of the infringement from the block store for comparison

consensus/reactor_test.go

@@ -236,6 +236,7 @@ func (m *mockEvidencePool) IsPending(evidence types.Evidence) bool {
 	return false
 }
 func (m *mockEvidencePool) AddPOLC(types.ProofOfLockChange) error { return nil }
+func (m *mockEvidencePool) Header(int64) *types.Header            { return nil }
 
 //------------------------------------
 

consensus/replay_stubs.go

@@ -56,6 +56,7 @@ func (emptyEvidencePool) Update(*types.Block, sm.State)           {}
 func (emptyEvidencePool) IsCommitted(types.Evidence) bool         { return false }
 func (emptyEvidencePool) IsPending(types.Evidence) bool           { return false }
 func (emptyEvidencePool) AddPOLC(types.ProofOfLockChange) error   { return nil }
+func (emptyEvidencePool) Header(int64) *types.Header              { return nil }
 
 //-----------------------------------------------------------------------------
 // mockProxyApp uses ABCIResponses to give the right results.

evidence/pool.go

@@ -181,11 +181,10 @@ func (evpool *Pool) AddEvidence(evidence types.Evidence) error {
 		// For lunatic validator evidence, a header needs to be fetched.
 		var header *types.Header
 		if _, ok := ev.(*types.LunaticValidatorEvidence); ok {
-			blockMeta := evpool.blockStore.LoadBlockMeta(ev.Height())
-			if blockMeta == nil {
+			header = evpool.Header(ev.Height())
+			if header == nil {
 				return fmt.Errorf("don't have block meta at height #%d", ev.Height())
 			}
-			header = &blockMeta.Header
 		}
 
 		// 1) Verify against state.
@@ -266,7 +265,7 @@ func (evpool *Pool) IsCommitted(evidence types.Evidence) bool {
 	return ok
 }
 
-// Checks whether the evidence is already pending. DB errors are passed to the logger.
+// IsPending checks whether the evidence is already pending. DB errors are passed to the logger.
 func (evpool *Pool) IsPending(evidence types.Evidence) bool {
 	key := keyPending(evidence)
 	ok, err := evpool.evidenceStore.Has(key)
@@ -306,6 +305,16 @@ func (evpool *Pool) SetLogger(l log.Logger) {
 	evpool.logger = l
 }
 
+// Header gets the header from the block store at a specified height.
+// Is used for validation of LunaticValidatorEvidence
+func (evpool *Pool) Header(height int64) *types.Header {
+	blockMeta := evpool.blockStore.LoadBlockMeta(height)
+	if blockMeta == nil {
+		return nil
+	}
+	return &blockMeta.Header
+}
+
 // ValidatorLastHeight returns the last height of the validator w/ the
 // given address. 0 - if address never was a validator or was such a
 // long time ago (> ConsensusParams.Evidence.MaxAgeDuration && >

state/mocks/evidence_pool.go

@@ -28,6 +28,22 @@ func (_m *EvidencePool) AddEvidence(_a0 types.Evidence) error {
 	return r0
 }
 
+// Header provides a mock function with given fields: _a0
+func (_m *EvidencePool) Header(_a0 int64) *types.Header {
+	ret := _m.Called(_a0)
+
+	var r0 *types.Header
+	if rf, ok := ret.Get(0).(func(int64) *types.Header); ok {
+		r0 = rf(_a0)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*types.Header)
+		}
+	}
+
+	return r0
+}
+
 // IsCommitted provides a mock function with given fields: _a0
 func (_m *EvidencePool) IsCommitted(_a0 types.Evidence) bool {
 	ret := _m.Called(_a0)

state/services.go

@@ -45,6 +45,7 @@ type EvidencePool interface {
 	Update(*types.Block, State)
 	IsCommitted(types.Evidence) bool
 	IsPending(types.Evidence) bool
+	Header(int64) *types.Header
 }
 
 // MockEvidencePool is an empty implementation of EvidencePool, useful for testing.
@@ -55,3 +56,4 @@ func (me MockEvidencePool) AddEvidence(types.Evidence) error        { return nil
 func (me MockEvidencePool) Update(*types.Block, State)              {}
 func (me MockEvidencePool) IsCommitted(types.Evidence) bool         { return false }
 func (me MockEvidencePool) IsPending(types.Evidence) bool           { return false }
+func (me MockEvidencePool) Header(int64) *types.Header              { return nil }

state/validation.go

@@ -142,7 +142,16 @@ func validateBlock(evidencePool EvidencePool, stateDB dbm.DB, state State, block
 				continue
 			}
 		}
-		if err := VerifyEvidence(stateDB, state, ev, &block.Header); err != nil {
+
+		var header *types.Header
+		if _, ok := ev.(*types.LunaticValidatorEvidence); ok {
+			header = evidencePool.Header(ev.Height())
+			if header == nil {
+				return fmt.Errorf("don't have block meta at height #%d", ev.Height())
+			}
+		}
+
+		if err := VerifyEvidence(stateDB, state, ev, header); err != nil {
 			return types.NewErrEvidenceInvalid(ev, err)
 		}
 	}