Is there a way to mint ERC20 asset balance through Root in runtime?

[dudo50]

Dear Moonbeam team,

We are trying to create dryrun balance bypass by minting ourselves assets through root so we can try out the XCM messages, however, the Moonbeam chain uses ERC20 assets so assets pallet is no longer working. Is there a way to modify ourselves a balance through root so we can mint ourselves erc20 assets to be able to send XCM?

Scenario:

Suppose we want to send DOT from Moonbeam to Hydration

We mind ourselves GLMR through balances pallet

But we also need to mint ourselves xcDOT erc20, in order for the XCM to be successful. We have not found a way to do this. Is there a way?

Thanks in advance!

[RomarQ]

Moonbeam foreign assets are native ERC-20 contracts, https://github.com/moonbeam-foundation/moonbeam/blob/master/pallets/moonbeam-foreign-assets/resources/foreign_erc20.sol

Storage layout:

{
	"astId": 332,
	"contract": "contracts/erc20.sol:MyToken",
	"label": "_balances",
	"offset": 0,
	"slot": "0",
	"type": "t_mapping(t_address,t_uint256)"
},
{
    "astId": 8,
    "contract": "contracts/erc20.sol:MyToken",
    "label": "_owner",
    "offset": 1,
    "slot": "5",
    "type": "t_address"
}

Each entry in the balances mapping is stored at: keccak256(paddress_address + padded_slot)

Where:

paddress_address is the 20-byte address, left-padded to 32 bytes.

padded_slot is the slot number of the mapping (0 for balances), left-padded to 32 bytes.

+ denotes concatenation.

You can calculate the slot with:

pragma solidity ^0.8.0;

contract StorageSlotCalculator {
    function calculateMappingSlot(address key, uint256 mappingSlot) external pure returns (bytes32) {
        return keccak256(abi.encodePacked(
            bytes32(uint256(uint160(key))), // pad the address to 32 bytes
            bytes32(mappingSlot)            // pad the slot to 32 bytes
        ));
    }
}

Example: calculateMappingSlot(0xf24FF3a9CF04c71Dbc94D0b566f7A27B94566cac, 0)
Result: 0x01fdf5799e0754c521507d0817d9efa5aac0acf23d4df8a7c71e8fc760ec7d14

You can then copy the encoded storage key:

0xffffffff0000000000000000000000000000000a is an example erc20 contract address

And then set 100000000000000000000 balance for your account:

[RomarQ]

If you find the above too complex, you can also modify the asset owner, which is at slot 5 and then call function mintInto(address to, uint256 amount) in the erc-20 contract.

0x6d6f646c666f7267617373740000000000000000 is the EvmForeignAssets account. You just need to replace it with your own address, mint some balance and then change back the owner to 0x6d6f646c666f7267617373740000000000000000.

[dudo50]

@RomarQ thank you for your thorough explanation!

We are going to try it and will let you know if we succeed.

With kind regards,
Team ParaSpell✨

[dudo50]

@RomarQ

Do you know which extrinsic should we use and what to fill where?

Thanks in advance!

With kind regards,
Team ParaSpell✨

[RomarQ]

You can use https://remix.ethereum.org to interact with erc-20.

If it is easier I can provide the storage key and value you need to set with system.setStorage.

For that I just need to know in which account you need the balance.

[dudo50]

EDIT:

NVM, we understand it now. Thanks a lot!

I will close this issue if we manage to perform these actions successfully.

With kind regards,
Team ParaSpell✨

[RomarQ]

Storage key: 0x1da53b775b270400e7e61ed5cbc5a146ab1160471b1418779239ba8e2b847e421f720ca3a567a7892f51ba4eabe649ccffffffff1fcacbd218edc0eba20fc2308c778080adf054024eb585d942fdcc11210daf107a1bc6e523bf240517ff9a4d6c4555b1a9ec0fd6a35164bd2ea9c9462b97370d

Storage value: 0x0000000000000000000000000000000000000000000000056bc75e2d63100000

This will set the balance to 100000000000000000000 on account 0x24D18dbFBcEd732EAdF98EE520853e13909fE258 for asset xcDOT.

[dudo50]

Thanks!

With kind regards,
Team ParaSpell✨

[dudo50]

Yep, just verified it, it works. I tried sending 100 DOT, which I did not have on that account to Hydration and it worked.

Thanks a lot again!

Closing this issue as matter is now resolved.

With kind regards,
Team ParaSpell✨

[dudo50]

Hey @RomarQ reopening this, as Wormhole assets do not seem to work this way. Can you please let us know how to mint wormhole assets through root? When applying same process we get local execution incomplete meaning assets did not mint.

Thanks!

[dudo50]

For example WH USDC - 0x931715fee2d06333043d11f658c8ce934ac61d0c

[dudo50]

cc @RomarQ is there any way? Thanks in advance!