// SPDX-License-Identifier: MIT // OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/SignatureChecker.sol) pragma solidity ^0.8.0; import "./ECDSAUpgradeable.sol"; import "../AddressUpgradeable.sol"; import "../../interfaces/IERC1271Upgradeable.sol"; /** * @dev Signature verification helper that can be used instead of `ECDSA.recover` to seamlessly support both ECDSA * signatures from externally owned accounts (EOAs) as well as ERC1271 signatures from smart contract wallets like * Argent and Gnosis Safe. * * _Available since v4.1._ */ library SignatureCheckerUpgradeable { /** * @dev Checks if a signature is valid for a given signer and data hash. If the signer is a smart contract, the * signature is validated against that smart contract using ERC1271, otherwise it's validated using `ECDSA.recover`. * * NOTE: Unlike ECDSA signatures, contract signatures are revocable, and the outcome of this function can thus * change through time. It could return true at block N and false at block N+1 (or the opposite). */ function isValidSignatureNow( address signer, bytes32 hash, bytes memory signature ) internal view returns (bool) { (address recovered, ECDSAUpgradeable.RecoverError error) = ECDSAUpgradeable.tryRecover(hash, signature); if (error == ECDSAUpgradeable.RecoverError.NoError && recovered == signer) { return true; } (bool success, bytes memory result) = signer.staticcall( abi.encodeWithSelector(IERC1271Upgradeable.isValidSignature.selector, hash, signature) ); return (success && result.length == 32 && abi.decode(result, (bytes32)) == bytes32(IERC1271Upgradeable.isValidSignature.selector)); } }