Should we apply the same logic to all reserved system contracts addresses?

[yangby-cryptape]

Description

• As the following code defined:

  axon/core/executor/src/system_contract/mod.rs

  Lines 42 to 47 in 6a574cd

  	pub const fn system_contract_address(addr: u8) -> H160 {
  	H160([
  	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  	0xff, 0xff, 0xff, 0xff, addr,
  	])
  	}

  All addresses between 0xffff..ff00 and 0xffff..ffff are system contracts.

• But only 3 addresses in them are used.

  axon/core/executor/src/system_contract/metadata/mod.rs

  Line 29 in 6a574cd

  pub const METADATA_CONTRACT_ADDRESS: H160 = system_contract_address(0x1);

  
  

  axon/core/executor/src/system_contract/ckb_light_client/mod.rs

  Line 20 in 6a574cd

  pub const CKB_LIGHT_CLIENT_CONTRACT_ADDRESS: H160 = system_contract_address(0x2);

  
  

  axon/core/executor/src/system_contract/image_cell/mod.rs

  Line 20 in 6a574cd

  pub const IMAGE_CELL_CONTRACT_ADDRESS: H160 = system_contract_address(0x3);

• When executing a system contract, only above 3 contracts that have been clearly defined are dispatched to the system contracts process.

  axon/core/executor/src/lib.rs

  Lines 152 to 153 in 6a574cd

  	let mut r = system_contract_dispatch(adapter, tx)
  	.unwrap_or_else(|| Self::evm_exec(adapter, &config, &precompiles, tx));

  
  

  axon/core/executor/src/system_contract/mod.rs

  Lines 204 to 223 in 6a574cd

  	pub fn system_contract_dispatch<Adapter: ExecutorAdapter + ApplyBackend>(
  	adapter: &mut Adapter,
  	tx: &SignedTransaction,
  	) -> Option<TxResp> {
  	if let Some(addr) = tx.get_to() {
  	log::debug!("execute addr {:#x}", addr);
  	if addr == NATIVE_TOKEN_CONTRACT_ADDRESS {
  	return Some(NativeTokenContract::default().exec_(adapter, tx));
  	} else if addr == METADATA_CONTRACT_ADDRESS {
  	return Some(MetadataContract::default().exec_(adapter, tx));
  	} else if addr == CKB_LIGHT_CLIENT_CONTRACT_ADDRESS {
  	return Some(CkbLightClientContract::default().exec_(adapter, tx));
  	} else if addr == IMAGE_CELL_CONTRACT_ADDRESS {
  	return Some(ImageCellContract::default().exec_(adapter, tx));
  	}
  	}
  	None
  	}

  Other executions which are to the reserved addresses of system contracts are processed as normal executions.

• As far as we know, a normal contract and a system contract are very different.

  • They have different restrictions, for example: In design, are system contracts addresses able to be payable? #1490.
  • System contracts use special storage, which are isolated.
    • They use different JSON-RPC APIs for storage data and proofs (ref: May need another APIs to get the proofs of Axon's system contracts #1561).

---

❓ So, my question is: once a reserved system contract is enabled in the future, how to treat the difference between now and then after that?

An example of current Axon:

• Now, 0xffff..ff04 is an undeployed system contract address.
  • It's payable.
  • The data, even be empty, should be accessed with eth_getStorageAt and the proofs of its storage should be generated with eth_getProof.
• Once it is deployed.
  • It's NOT payable.
  • The data should be accessed with axon_getSystemContractStorageAt and the proofs of its storage should be generated with axon_getSystemContractProof.¹

Should we apply the same logic to those reserved system contracts now?

Let all system contracts, even reserved system contracts:

• Should NOT be payable.
• The data should be accessed with axon_getSystemContractStorageAt and the proofs of its storage should be generated with axon_getSystemContractProof.

Footnotes

1. https://github.com/axonweb3/axon/issues/1561#issuecomment-1814445346 ↩

[Flouse]

My Humble Opinion

1. reserved system_contract_addresses is defined in

axon/core/executor/src/system_contract/mod.rs

Lines 42 to 47 in 6a574cd

	pub const fn system_contract_address(addr: u8) -> H160 {
	H160([
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff, addr,
	])
	}

2. Just return error in eth_getStorageAt and eth_getProof when an address is system_contract_address

3. fix system_contract_dispatch function
   It should handle all reserved system_contract_addresses.

Need confirmations before coding

• @KaoImin
• @driftluo
• @yangby-cryptape

[Flouse]

• Just return error in eth_getStorageAt and eth_getProof when an address is system_contract_address

I think this change is not implemented.

Test

curl -X POST localhost:8000 \
  --data '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0xffffffffffffffffffffffffffffffffffffff04", "0x0", "latest"], "id": 1}' \
  --header 'Content-Type: application/json' 

# Result
{"jsonrpc":"2.0","id":1,"result":"0x00000000000000000000000000000000000000000000000000000000000004d2"}

Expected result

Not allow to call system contract address

ref: #1561 (comment)