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register attest via signature + tests
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@vimageDE
vimageDE committed Nov 4, 2024
1 parent acf55b0 commit ca180f2
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Showing 2 changed files with 389 additions and 31 deletions.
108 changes: 85 additions & 23 deletions src/examples/allocator/ServerAllocator.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,13 @@ import {IERC1271} from "lib/openzeppelin-contracts/contracts/interfaces/IERC1271
contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
using ECDSA for bytes32;

struct RegisterAttest {
address signer;
bytes32 attestHash;
uint256 expiration;
uint256 nonce;
}

struct NonceConsumption {
address signer;
uint256[] nonces;
Expand All @@ -22,6 +29,10 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
// keccak256("Attest(address,address,address,uint256,uint256)")
bytes4 private constant _ATTEST_SELECTOR = 0x1a808f91;

// keccak256("RegisterAttest(address signer,bytes32 attestHash,uint256 expiration,uint256 nonce)")
bytes32 private constant _ATTEST_TYPE_HASH =
0xaf2dfd3fe08723f490d203be627da2725f4ad38681e455221da2fc1a633bbb18;

// keccak256("Allocator(bytes32 hash)")
bytes32 private constant _ALLOCATOR_TYPE_HASH =
0xcdf324dc7c3490a07fbbb105911393dcbc0676ac7c6c1c32c786721de6179e70;
Expand All @@ -34,8 +45,10 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {

mapping(address => uint256) private _signers;
address[] private _activeSigners;

mapping(bytes32 => uint256) private _attestExpirations;
mapping(bytes32 => uint256) private _attestCounts;
mapping(bytes32 => bool) private _attestSignatures;

event SignerAdded(address signer_);
event SignerRemoved(address signer_);
Expand All @@ -49,6 +62,7 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
error InvalidCaller(address caller_, address expected_);
error InvalidSigner(address signer_);
error InvalidSignature(bytes signature_, address signer_);
error AlreadyUsedSig(bytes32 attest_, uint256 nonce);
error InvalidInput();

modifier isSigner(address signer_) {
Expand Down Expand Up @@ -95,15 +109,34 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
bytes32 attest_,
uint256 expiration_
) external isSigner(msg.sender) {
if (expiration_ < block.timestamp) {
revert Expired(expiration_, block.timestamp);
}
uint256 count = ++_attestCounts[attest_];
bytes32 countedAttest = keccak256(abi.encode(attest_, count));
_registerAttest(attest_, expiration_);
}

_attestExpirations[countedAttest] = expiration_;
/// @dev Nonce management in the RegisterAttest is only required for multiple registers of the same attest with the same expiration.
function registerAttestViaSignature(
RegisterAttest calldata attest_,
bytes calldata signature_
) external {
bytes32 _attestWithNonce = keccak256(
abi.encode(attest_.attestHash, attest_.expiration, attest_.nonce)
);
if (_attestSignatures[_attestWithNonce]) {
revert AlreadyUsedSig(attest_.attestHash, attest_.nonce);
}
address signer = _validateSignedAttest(
attest_.signer,
attest_.attestHash,
attest_.expiration,
attest_.nonce,
signature_
);
if (signer != attest_.signer || !_containsSigner(signer)) {
revert InvalidSignature(signature_, signer);
}

emit AttestRegistered(attest_, expiration_);
// Invalidate signature
_attestSignatures[_attestWithNonce] = true;
_registerAttest(attest_.attestHash, attest_.expiration);
}

/// @dev There is no way to uniquely identify a transfer, so the contract relies on its own accounting of registered attests.
Expand Down Expand Up @@ -186,21 +219,6 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
) external view returns (bytes4 magicValue) {
address signer = _validateSignedHash(hash_, signature_);
if (!_containsSigner(signer)) {
// Check registered attests as fallback
/// TODO: This fallback must modify state to not be a source of endless verifications.
// uint256 count = _attestCounts[hash_];
// if (count != 0) {
// for (uint256 i = count; i > 0; --i) {
// bytes32 countedAttest = keccak256(abi.encode(hash_, i));
// if (_attestExpirations[countedAttest] >= block.timestamp) {
// // Found a valid registered attest

// // _attestCounts[hash_] = --count;
// // delete _attestExpirations[countedAttest];
// return IERC1271.isValidSignature.selector;
// }
// }
// }
revert InvalidSignature(signature_, signer);
}
return IERC1271.isValidSignature.selector;
Expand Down Expand Up @@ -235,6 +253,18 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
return _COMPACT_CONTRACT;
}

function _registerAttest(bytes32 attest_, uint256 expiration_) internal {
if (expiration_ < block.timestamp) {
revert Expired(expiration_, block.timestamp);
}
uint256 count = ++_attestCounts[attest_];
bytes32 countedAttest = keccak256(abi.encode(attest_, count));

_attestExpirations[countedAttest] = expiration_;

emit AttestRegistered(attest_, expiration_);
}

/// Todo: This will lead to always the last registered hash being consumed.
function _consumeNonces(
uint256[] calldata nonces_,
Expand All @@ -258,6 +288,37 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
emit NoncesConsumed(nonces_);
}

function _validateSignedAttest(
address signer_,
bytes32 hash_,
uint256 expiration_,
uint256 nonce,
bytes calldata signature_
) internal view returns (address) {
bytes32 message = _hashAttest(signer_, hash_, expiration_, nonce);
return message.recover(signature_);
}

function _hashAttest(
address signer_,
bytes32 hash_,
uint256 expiration_,
uint256 nonce_
) internal view returns (bytes32) {
return
_hashTypedDataV4(
keccak256(
abi.encode(
_ATTEST_TYPE_HASH,
signer_,
hash_,
expiration_,
nonce_
)
)
);
}

function _validateSignedHash(
bytes32 hash_,
bytes calldata signature_
Expand Down Expand Up @@ -290,7 +351,8 @@ contract ServerAllocator is Ownable2Step, EIP712, IAllocator {
abi.encode(
_NONCE_CONSUMPTION_TYPE_HASH,
data_.signer,
data_.nonces
data_.nonces,
data_.attests
)
)
);
Expand Down
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