evidence: introduce time.Duration to evidence params (#4254)

* evidence: introduce time.Duration to evidence params

- add time.duration to evidence
- this pr is taking pr #2606 and updating it to use both time and height

- closes #2565

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* fix testing and genesis cfg in signer harness

* remove debugging fmt

* change maxageheight to maxagenumblocks, rename other things to block instead of height

* further check of duration

* check duration to not send peers outdated evidence

* change some lines, onward and upward

* refactor evidence package

* add a changelog pending entry

* make mockbadevidence have time and use it

* add what could possibly be called a test case

* remove mockbadevidence and mockgoodevidence in favor of mockevidence

* add a comment for err that is returned

* add a changelog for removal of good & bad evidence

* add a test for adding evidence

* fix test

* add ev to types in testcase

* Update evidence/pool_test.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update evidence/pool_test.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* fix tests

* fix linting

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

state/validation.go

@@ -158,13 +158,21 @@ func validateBlock(evidencePool EvidencePool, stateDB dbm.DB, state State, block
 // - it is internally consistent
 // - it was properly signed by the alleged equivocator
 func VerifyEvidence(stateDB dbm.DB, state State, evidence types.Evidence) error {
-	height := state.LastBlockHeight
+	var (
+		height         = state.LastBlockHeight
+		evidenceParams = state.ConsensusParams.Evidence
+	)
 
-	evidenceAge := height - evidence.Height()
-	maxAge := state.ConsensusParams.Evidence.MaxAge
-	if evidenceAge > maxAge {
+	ageNumBlocks := height - evidence.Height()
+	if ageNumBlocks > evidenceParams.MaxAgeNumBlocks {
 		return fmt.Errorf("evidence from height %d is too old. Min height is %d",
-			evidence.Height(), height-maxAge)
+			evidence.Height(), height-evidenceParams.MaxAgeNumBlocks)
+	}
+
+	ageDuration := state.LastBlockTime.Sub(evidence.Time())
+	if ageDuration > evidenceParams.MaxAgeDuration {
+		return fmt.Errorf("evidence created at %v has expired. Evidence can not be older than: %v",
+			evidence.Time(), state.LastBlockTime.Add(evidenceParams.MaxAgeDuration))
 	}
 
 	valset, err := LoadValidators(stateDB, evidence.Height())