Fix misbehaviour handling for solo machine

proto/ibc/lightclients/solomachine/v1/solomachine.proto

@@ -63,6 +63,7 @@ message SignatureAndData {
   bytes    signature                 = 1;
   DataType data_type                 = 2 [(gogoproto.moretags) = "yaml:\"data_type\""];
   bytes    data                      = 3;
+  uint64   timestamp                 = 4;
 }
 
 // TimestampedSignatureData contains the signature data and the timestamp of the

x/ibc/light-clients/06-solomachine/types/misbehaviour.go

@@ -85,6 +85,9 @@ func (sd SignatureAndData) ValidateBasic() error {
 	if sd.DataType == UNSPECIFIED {
 		return sdkerrors.Wrap(ErrInvalidSignatureAndData, "data type cannot be UNSPECIFIED")
 	}
+	if sd.Timestamp == 0 {
+		return sdkerrors.Wrap(ErrInvalidSignatureAndData, "timestamp cannot be 0")
+	}
 
 	return nil
 }

x/ibc/light-clients/06-solomachine/types/misbehaviour_handle.go

@@ -49,16 +49,23 @@ func (cs ClientState) CheckMisbehaviourAndUpdateState(
 
 // verifySignatureAndData verifies that the currently registered public key has signed
 // over the provided data and that the data is valid. The data is valid if it can be
-// unmarshaled into the specified data type.
+// unmarshaled into the specified data type or the timestamp of the signature is less
+// than the consensus state timestamp.
 func verifySignatureAndData(cdc codec.BinaryMarshaler, clientState ClientState, misbehaviour *Misbehaviour, sigAndData *SignatureAndData) error {
+	// timestamp less than consensus state would always fail and not succeed in fooling the
+	// light client
+	if sigAndData.Timestamp < clientState.ConsensusState.Timestamp {
+		return sdkerrors.Wrapf(clienttypes.ErrInvalidMisbehaviour, "timestamp is less than consensus state timestamp (%d < %d)", sigAndData.Timestamp, clientState.ConsensusState.Timestamp)
+	}
+
 	// ensure data can be unmarshaled to the specified data type
 	if _, err := UnmarshalDataByType(cdc, sigAndData.DataType, sigAndData.Data); err != nil {
 		return err
 	}
 
 	data, err := MisbehaviourSignBytes(
 		cdc,
-		misbehaviour.Sequence, clientState.ConsensusState.Timestamp,
+		misbehaviour.Sequence, sigAndData.Timestamp,
 		clientState.ConsensusState.Diversifier,
 		sigAndData.DataType,
 		sigAndData.Data,

x/ibc/light-clients/06-solomachine/types/misbehaviour_handle_test.go

@@ -75,6 +75,34 @@ func (suite *SoloMachineTestSuite) TestCheckMisbehaviourAndUpdateState() {
 					misbehaviour = m
 				}, false,
 			},
+			{
+				"invalid SignatureOne timestamp",
+				func() {
+					clientState = solomachine.ClientState()
+					m := solomachine.CreateMisbehaviour()
+
+					m.SignatureOne.Timestamp = 1000000000000
+					misbehaviour = m
+				}, false,
+			},
+			{
+				"invalid SignatureTwo timestamp",
+				func() {
+					clientState = solomachine.ClientState()
+					m := solomachine.CreateMisbehaviour()
+
+					m.SignatureTwo.Timestamp = 1000000000000
+					misbehaviour = m
+				}, false,
+			},
+			{
+				"timestamp is less than consensus state timestamp",
+				func() {
+					clientState = solomachine.ClientState()
+					solomachine.Time = solomachine.Time - 5
+					misbehaviour = solomachine.CreateMisbehaviour()
+				}, false,
+			},
 			{
 				"invalid first signature data",
 				func() {

x/ibc/light-clients/06-solomachine/types/misbehaviour_test.go

@@ -96,6 +96,18 @@ func (suite *SoloMachineTestSuite) TestMisbehaviourValidateBasic() {
 					misbehaviour.SignatureTwo.DataType = types.UNSPECIFIED
 				}, false,
 			},
+			{
+				"timestamp for SignatureOne is zero",
+				func(misbehaviour *types.Misbehaviour) {
+					misbehaviour.SignatureOne.Timestamp = 0
+				}, false,
+			},
+			{
+				"timestamp for SignatureTwo is zero",
+				func(misbehaviour *types.Misbehaviour) {
+					misbehaviour.SignatureTwo.Timestamp = 0
+				}, false,
+			},
 		}
 
 		for _, tc := range testCases {