chore: jail validators with invalid balances (#1192)

# Related Github tickets

- VolumeFi#1037

# Background

If validators have invalid (or missing) balances, we jail them.
Alternatively we could leave them out of the relayer pool, but this
makes it more visible when something has failed.

For this mechanism to work properly, we need
palomachain/pigeon#399 to be merged as well.

# Testing completed

- [x] test coverage exists or has been added/updated
- [x] tested in a private testnet

# Breaking changes

- [x] I have checked my code for breaking changes
- [x] If there are breaking changes, there is a supporting migration.

x/evm/keeper/attest_validator_balances.go

@@ -54,6 +54,7 @@ func (k Keeper) processValidatorBalanceProof(
 			if err != nil {
 				k.Logger(ctx).Error("error while getting validator address", err)
 			}
+
 			hexAddr, balanceStr := common.HexToAddress(request.HexAddresses[i]), winner.Balances[i]
 			balance, ok := new(big.Int).SetString(balanceStr, 10)
 			if !ok {
@@ -63,8 +64,17 @@ func (k Keeper) processValidatorBalanceProof(
 					"val-addr", valAddr,
 					"eth-addr", hexAddr,
 				)
-				// WHAT TO DO NOW?!?!?! jail the poor fellow that has invalid balance format??
-				// blame the flock for reporting this??!?
+
+				reason := fmt.Sprintf(types.JailReasonInvalidBalance, chainReferenceID, balanceStr)
+				if err = k.Valset.Jail(ctx, valAddr, reason); err != nil {
+					k.Logger(ctx).Error(
+						"error jailing validator",
+						"err", err,
+						"val-addr", valAddr,
+						"eth-addr", hexAddr,
+					)
+				}
+
 				continue
 			}
 
@@ -76,6 +86,7 @@ func (k Keeper) processValidatorBalanceProof(
 					"eth-addr", hexAddr,
 				)
 			}
+
 			if balance.Cmp(minBalance) == -1 || balance.Cmp(big.NewInt(0)) == 0 {
 				isJailed, err := k.Valset.IsJailed(ctx, valAddr)
 				if err != nil {

x/evm/keeper/attest_validator_balances_test.go

@@ -1,6 +1,7 @@
 package keeper
 
 import (
+	"fmt"
 	"math/big"
 	"time"
 
@@ -88,4 +89,50 @@ var _ = g.Describe("attest validator balance", func() {
 			Expect(err).To(BeNil())
 		})
 	})
+
+	g.Context("with invalid balances", func() {
+		g.BeforeEach(func() {
+			minBalance = big.NewInt(50)
+			validatorBalances := []string{"1000", "", "5000"}
+			req = &types.ValidatorBalancesAttestation{
+				FromBlockTime: time.Unix(999, 0),
+				HexAddresses: slice.Map(validatorBalances, func(b string) string {
+					return common.BytesToAddress([]byte("addr_" + b)).Hex()
+				}),
+				ValAddresses: slice.Map(validatorBalances, func(b string) sdk.ValAddress {
+					return sdk.ValAddress("addr_" + b)
+				}),
+			}
+			evidenceThatWon = &types.ValidatorBalancesAttestationRes{
+				BlockHeight: 123,
+				Balances:    validatorBalances,
+			}
+
+			reason := fmt.Sprintf(types.JailReasonInvalidBalance, "chain-id", "")
+			v.On("Jail", mock.Anything, req.ValAddresses[1], reason).Return(nil)
+
+			for i, balance := range validatorBalances {
+				// The ones with invalid balance won't be updated, so we skip
+				if balance == "" {
+					continue
+				}
+
+				n, _ := new(big.Int).SetString(balance, 10)
+				v.On(
+					"SetValidatorBalance",
+					mock.Anything,
+					req.ValAddresses[i],
+					"evm",
+					"chain-id",
+					req.HexAddresses[i],
+					n,
+				).Return(nil)
+			}
+		})
+
+		g.It("updates the balances and jail those with invalid balances", func() {
+			err := subject()
+			Expect(err).To(BeNil())
+		})
+	})
 })

x/evm/types/jail_reason.go

@@ -2,4 +2,5 @@ package types
 
 const (
 	JailReasonNotEnoughFunds = "not enough funds in the target chain (%s). Has %s. Min required: %s."
+	JailReasonInvalidBalance = "invalid balance information in the target chain (%s): %s."
 )