chore: add verify remove_signers

Signed-off-by: Jeremy Letang <me@jeremyletang.com>

cmd/vega/commands/bridge/erc20.go

@@ -38,6 +38,7 @@ type ERC20Cmd struct {
 
 	AddSigner              ERC20AddSignerCmd              `command:"add_signer"                description:"Create signature to add a new signer to the erc20 bridge"`
 	RemoveSigner           ERC20RemoveSignerCmd           `command:"remove_signer"             description:"Create signature to remove a signer from the erc20 bridge"`
+	VerifyRemoveSigner     ERC20VerifyRemoveSignerCmd     `command:"verify_remove_signer"      description:"Verify signatures to remove a signer from the erc20 bridge"`
 	SetThreshold           ERC20SetThresholdCmd           `command:"set_threshold"             description:"Create signature to change the threshold of required signature to apply changes to the bridge"`
 	BurnNonce              ERC20BurnNonceCmd              `command:"burn_nonce"                description:"Create signature to burn and existing nonce in order to prevent it to be used on the bridge"`
 	ListAsset              ERC20ListAssetCmd              `command:"list_asset"                description:"Add a new erc20 asset to the erc20 bridge"`
@@ -91,6 +92,7 @@ func ERC20() *ERC20Cmd {
 	erc20Cmd = &ERC20Cmd{
 		AddSigner:              ERC20AddSignerCmd{},
 		RemoveSigner:           ERC20RemoveSignerCmd{},
+		VerifyRemoveSigner:     ERC20VerifyRemoveSignerCmd{},
 		SetThreshold:           ERC20SetThresholdCmd{},
 		ListAsset:              ERC20ListAssetCmd{},
 		VerifyListAsset:        ERC20VerifyListAssetCmd{},
@@ -398,6 +400,46 @@ func (opts *ERC20RemoveSignerCmd) Execute(_ []string) error {
 	return nil
 }
 
+type ERC20VerifyRemoveSignerCmd struct {
+	OldSigner  string `description:"Ethereum address of signer to remove"                 long:"old-signer" required:"true"`
+	Submitter  string `description:"Ethereum address of the submitter of the transaction" long:"submitter"  required:"true"`
+	Nonce      string `description:"A nonce for this signature"                           long:"nonce"      required:"true"`
+	Signatures string `description:"The list of signatures from the validators"           long:"signatures" required:"true"`
+}
+
+func (opts *ERC20VerifyRemoveSignerCmd) Execute(_ []string) error {
+	if _, err := flags.NewParser(opts, flags.Default|flags.IgnoreUnknown).Parse(); err != nil {
+		return err
+	}
+
+	nonce, overflowed := num.UintFromString(opts.Nonce, 10)
+	if overflowed {
+		return errors.New("invalid nonce, needs to be base 10 and not overflow")
+	}
+
+	if len(opts.Signatures) <= 0 {
+		return errors.New("missing signatures")
+	}
+
+	if (len(opts.Signatures)-2)%130 != 0 {
+		return errors.New("invalid signatures format")
+	}
+
+	multiSigControl := bridges.NewERC20MultiSigControl(nil, erc20Cmd.ChainID, erc20Cmd.ChainID == "")
+	signers, err := multiSigControl.VerifyRemoveSigner(
+		opts.OldSigner, opts.Submitter, nonce, opts.Signatures,
+	)
+	if err != nil {
+		return fmt.Errorf("unable to verify signature: %w", err)
+	}
+
+	sort.Strings(signers)
+	for _, v := range signers {
+		fmt.Printf("%v\n", v)
+	}
+	return nil
+}
+
 type ERC20SetThresholdCmd struct {
 	NewThreshold uint16 `description:"The new threshold to be used on the bridge"           long:"new-threshold" required:"true"`
 	Submitter    string `description:"Ethereum address of the submitter of the transaction" long:"submitter"     required:"true"`

core/bridges/erc20_multisigcontrol.go

@@ -16,6 +16,10 @@
 package bridges
 
 import (
+	"encoding/hex"
+	"fmt"
+
+	crypto "code.vegaprotocol.io/vega/libs/crypto/signature"
 	"code.vegaprotocol.io/vega/libs/num"
 
 	"github.com/ethereum/go-ethereum/accounts/abi"
@@ -164,10 +168,57 @@ func (e *ERC20MultiSigControl) AddSigner(
 	return sign(e.signer, msg)
 }
 
+func (e *ERC20MultiSigControl) VerifyRemoveSigner(
+	oldSigner, submitter string,
+	nonce *num.Uint,
+	signatures string,
+) ([]string, error) {
+	msg, err := e.buildRemoveSignerMessage(
+		oldSigner, submitter, nonce,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	addresses := []string{}
+	var hexCurrent string
+	signatures = signatures[2:]
+	for len(signatures) > 0 {
+		hexCurrent, signatures = signatures[0:130], signatures[130:]
+		current, err := hex.DecodeString(hexCurrent)
+		if err != nil {
+			return nil, fmt.Errorf("invalid signature format: %w", err)
+		}
+
+		address, err := crypto.RecoverEthereumAddress(msg, current)
+		if err != nil {
+			return nil, fmt.Errorf("error recovering ethereum address: %w", err)
+		}
+
+		addresses = append(addresses, address.Hex())
+	}
+
+	return addresses, nil
+}
+
 func (e *ERC20MultiSigControl) RemoveSigner(
 	oldSigner, submitter string,
 	nonce *num.Uint,
 ) (*SignaturePayload, error) {
+	msg, err := e.buildRemoveSignerMessage(
+		oldSigner, submitter, nonce,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return sign(e.signer, msg)
+}
+
+func (e *ERC20MultiSigControl) buildRemoveSignerMessage(
+	oldSigner, submitter string,
+	nonce *num.Uint,
+) ([]byte, error) {
 	typAddr, err := abi.NewType("address", "", nil)
 	if err != nil {
 		return nil, err
@@ -202,10 +253,5 @@ func (e *ERC20MultiSigControl) RemoveSigner(
 		return nil, err
 	}
 
-	msg, err := packScheme(buf, submitter, e.chainID, e.v1)
-	if err != nil {
-		return nil, err
-	}
-
-	return sign(e.signer, msg)
+	return packScheme(buf, submitter, e.chainID, e.v1)
 }