Smart contract based signature support in cluster definitions/locks

[OisinKyne]

🎯 Problem to be solved

Cluster locks with EIP1271 smart contract signatures fail normal signature checks. This means you need to run charon run --no-verify which is a reduction of the security model.

🛠️ Proposed solution

If operator_enr_signature and operator_config_hash fail validation, and we have been provided an --execution-rpc-api flag (doesn't exist yet), we fallback and try smart contract based signature check.

If the signatures fail to verify, and no JSON RPC is provided, we throw the normal verification error log, but suggest that if the cluster has smart contract wallet operators they need to provide a json rpc uri or to use --no-verify.

🧪 Tests

• Tested by new automated unit/integration/smoke tests
• Manually tested on core team/canary/test clusters
• Manually tested on local compose simnet

[DiogoSantoss]

Possible execution layer clients:

• geth
• ergion
• go-web3
• ethgo
• etc...

The standard is usually geth.

This can be installed by doing:

go get -d github.com/ethereum/go-ethereum/...

It provides a simple way to create a JSON-RPC client by doing:

client, err := ethclient.Dial("YOUR_RPC_URL")

which can then be used to handle requests to a EL client:

blockNumber, err := client.BlockNumber(context.Background())

Furthermore, to solve the issue at hand we can use ABI (Application Binary Interface) to interact with contracts.

For example, one way of verifying contract signatures would be to create a contract interface:

parsedABI, err := abi.JSON(strings.NewReader(isValidSignatureABI))
contract := bind.NewBoundContract(address, parsedABI, client, client, client)
err = contract.Call(nil, &result, "isValidSignature", signedMessage, signature)

or alternatively, without creating a contract instance by manually enconding the signedMessage and signature into the ABI format:

parsedABI, err := abi.JSON(strings.NewReader(isValidSignatureABI))
encodedData, err := parsedABI.Pack("isValidSignature", signedMessage, signature)
msg := ethereum.CallMsg{
	To:   &address,
	Data: encodedData,
}

result, err := client.CallContract(context.Background(), msg, nil)
if string(result[:4]) == "0x1626ba7e" {
	fmt.Println("Valid signature")
} else {
	fmt.Println("Invalid signature")
}

Regarding its integration in Charon there some questions:

• Should it follow the same structure of eth2wrap ? By structure we mean, having lazy/multi clients, cache, wrapper, etc...
• Interesting metrics/features
  • eth_estimateGas - estimates how much gas is necessary for a transaction to complete
  • eth_gasPrice - current price per gas in wei
  • eth_getBalance - balance of given address