Use correct SealRandomnessLookbackLimit

checks.go

@@ -80,7 +80,7 @@ func checkPrecommit(ctx context.Context, maddr address.Address, si SectorInfo, t
 		return &ErrBadCommD{xerrors.Errorf("on chain CommD differs from sector: %s != %s", commD, si.CommD)}
 	}
 
-	if int64(height)-int64(si.TicketEpoch+SealRandomnessLookback) > SealRandomnessLookbackLimit {
+	if height-si.TicketEpoch+SealRandomnessLookback > SealRandomnessLookbackLimit(si.SectorType) {
 		return &ErrExpiredTicket{xerrors.Errorf("ticket expired: seal height: %d, head: %d", si.TicketEpoch+SealRandomnessLookback, height)}
 	}
 

constants.go

@@ -1,13 +1,17 @@
 package sealing
 
-// Epochs
-const Finality = 500
+import (
+	"github.com/filecoin-project/specs-actors/actors/abi"
+	"github.com/filecoin-project/specs-actors/actors/builtin/miner"
+)
 
 // Epochs
-const SealRandomnessLookback = Finality
+const SealRandomnessLookback = miner.ChainFinalityish
 
 // Epochs
-const SealRandomnessLookbackLimit = SealRandomnessLookback + 2000
+func SealRandomnessLookbackLimit(spt abi.RegisteredProof) abi.ChainEpoch {
+	return miner.MaxSealDuration[spt]
+}
 
 // Epochs
 const InteractivePoRepConfidence = 6

states.go

@@ -53,7 +53,7 @@ func (m *Sealing) getTicket(ctx statemachine.Context, sector SectorInfo) (abi.Se
 		return nil, 0, nil
 	}
 
-	ticketEpoch := epoch - miner.ChainFinalityish
+	ticketEpoch := epoch - SealRandomnessLookback
 	buf := new(bytes.Buffer)
 	if err := m.maddr.MarshalCBOR(buf); err != nil {
 		return nil, 0, err