Test additional invalid justifications (#626)

Test validation for invalid justifications with:
* inconsistent supplemental data
* insufficient power
* unknown signer
* evidence from another instance

Fixes #235

part of #249

emulator/instance.go

@@ -130,6 +130,10 @@ func (i *Instance) NewJustification(round uint64, step gpbft.Phase, vote gpbft.E
 		SupplementalData: i.supplementalData,
 		Value:            vote,
 	}
+	return i.NewJustificationWithPayload(payload, from...)
+}
+
+func (i *Instance) NewJustificationWithPayload(payload gpbft.Payload, from ...gpbft.ActorID) *gpbft.Justification {
 	msg := signing.MarshalPayloadForSigning(networkName, &payload)
 	qr := gpbft.QuorumResult{
 		Signers:    make([]int, len(from)),

gpbft/gpbft_test.go

@@ -1101,6 +1101,78 @@ func TestGPBFT_Validation(t *testing.T) {
 			},
 			errContains: "justification with unexpected phase",
 		},
+		{
+			name: "justification without strong quorum",
+			message: func(instance *emulator.Instance, driver *emulator.Driver) *gpbft.GMessage {
+				return &gpbft.GMessage{
+					Sender:        1,
+					Vote:          instance.NewPrepare(3, gpbft.ECChain{}),
+					Ticket:        emulator.ValidTicket,
+					Justification: instance.NewJustification(2, gpbft.COMMIT_PHASE, gpbft.ECChain{}, 0),
+				}
+			},
+			errContains: "has justification with insufficient power",
+		},
+		{
+			name: "justification with unknown signer",
+			message: func(instance *emulator.Instance, driver *emulator.Driver) *gpbft.GMessage {
+				otherInstance := emulator.NewInstance(t, 0, append(participants, gpbft.PowerEntry{
+					ID:    42,
+					Power: gpbft.NewStoragePower(1),
+				}), tipset0, tipSet1, tipSet2)
+
+				return &gpbft.GMessage{
+					Sender: 1,
+					Vote:   instance.NewPrepare(3, gpbft.ECChain{}),
+					Ticket: emulator.ValidTicket,
+					Justification: otherInstance.NewJustificationWithPayload(gpbft.Payload{
+						Instance:         instance.ID(),
+						Round:            2,
+						Step:             gpbft.COMMIT_PHASE,
+						SupplementalData: instance.SupplementalData(),
+						Value:            gpbft.ECChain{},
+					}, 0, 1, 2, 42),
+				}
+			},
+			errContains: "invalid signer index: 3",
+		},
+		{
+			name: "justification for another instance",
+			message: func(instance *emulator.Instance, driver *emulator.Driver) *gpbft.GMessage {
+				otherInstance := emulator.NewInstance(t, 33, participants, instance.Proposal()...)
+				return &gpbft.GMessage{
+					Sender:        1,
+					Vote:          instance.NewPrepare(3, gpbft.ECChain{}),
+					Ticket:        emulator.ValidTicket,
+					Justification: otherInstance.NewJustification(0, gpbft.PREPARE_PHASE, gpbft.ECChain{}, 0, 1, 2),
+				}
+			},
+			errContains: "message with instanceID 0 has evidence from instanceID: 33",
+		},
+		{
+			name: "justification with inconsistent supplemental data",
+			message: func(instance *emulator.Instance, driver *emulator.Driver) *gpbft.GMessage {
+				someCid, err := cid.Decode("bafy2bzacedgbq7e3eb4l3ryhbfckvez5mty6ylw5ulofkxql5bfxxji7xt5a2")
+				require.NoError(t, err)
+				require.NotEqual(t, instance.SupplementalData().PowerTable, someCid)
+				return &gpbft.GMessage{
+					Sender: 1,
+					Vote:   instance.NewPrepare(3, gpbft.ECChain{}),
+					Ticket: emulator.ValidTicket,
+					Justification: instance.NewJustificationWithPayload(gpbft.Payload{
+						Instance: instance.ID(),
+						Round:    2,
+						Step:     gpbft.COMMIT_PHASE,
+						SupplementalData: gpbft.SupplementalData{
+							Commitments: [32]byte{},
+							PowerTable:  someCid,
+						},
+						Value: gpbft.ECChain{},
+					}, 0, 1, 2),
+				}
+			},
+			errContains: "message and justification have inconsistent supplemental data",
+		},
 		{
 			name: "justification aggregate with unsorted signatures",
 			message: func(instance *emulator.Instance, driver *emulator.Driver) *gpbft.GMessage {