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Create _readSignatureType with minimal validation

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This commit is contained in:
Amir Bandeali 2019-09-02 20:34:23 -07:00
parent 48dfb3317a
commit a6b60f3230
1 changed files with 37 additions and 17 deletions
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54
contracts/exchange/contracts/src/MixinSignatureValidator.sol
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@ -186,11 +186,15 @@ contract MixinSignatureValidator is
pure
returns (bool needsRegularValidation)
{
SignatureType signatureType = _readValidSignatureType(
// Read the signatureType from the signature
SignatureType signatureType = _readSignatureType(
hash,
signerAddress,
signature
);
// Any signature type that makes an external call needs to be revalidated
// with every partial fill
needsRegularValidation =
signatureType == SignatureType.Wallet ||
signatureType == SignatureType.Validator ||
@ -396,7 +400,28 @@ contract MixinSignatureValidator is
}
}
/// Reads the `SignatureType` from the end of a signature and validates it.
/// @dev Reads the `SignatureType` from a signature with minimal validation.
function _readSignatureType(
bytes32 hash,
address signerAddress,
bytes memory signature
)
private
pure
returns (SignatureType signatureType)
{
if (signature.length == 0) {
LibRichErrors.rrevert(LibExchangeRichErrors.SignatureError(
LibExchangeRichErrors.SignatureErrorCodes.INVALID_LENGTH,
hash,
signerAddress,
signature
));
}
return SignatureType(uint8(signature[signature.length - 1]));
}
/// @dev Reads the `SignatureType` from the end of a signature and validates it.
function _readValidSignatureType(
bytes32 hash,
address signerAddress,
@ -406,6 +431,13 @@ contract MixinSignatureValidator is
pure
returns (SignatureType signatureType)
{
// Read the signatureType from the signature
SignatureType signatureType = _readSignatureType(
hash,
signerAddress,
signature
);
// Disallow address zero because it is ecrecover() returns zero on
// failure.
if (signerAddress == address(0)) {
@ -417,20 +449,8 @@ contract MixinSignatureValidator is
));
}
if (signature.length == 0) {
LibRichErrors.rrevert(LibExchangeRichErrors.SignatureError(
LibExchangeRichErrors.SignatureErrorCodes.INVALID_LENGTH,
hash,
signerAddress,
signature
));
}
// Read the last byte off of signature byte array.
uint8 signatureTypeRaw = uint8(signature[signature.length - 1]);
// Ensure signature is supported
if (signatureTypeRaw >= uint8(SignatureType.NSignatureTypes)) {
if (uint8(signatureType) >= uint8(SignatureType.NSignatureTypes)) {
LibRichErrors.rrevert(LibExchangeRichErrors.SignatureError(
LibExchangeRichErrors.SignatureErrorCodes.UNSUPPORTED,
hash,
@ -444,7 +464,7 @@ contract MixinSignatureValidator is
// signature array with invalid type or length. We may as well make
// it an explicit option. This aids testing and analysis. It is
// also the initialization value for the enum type.
if (SignatureType(signatureTypeRaw) == SignatureType.Illegal) {
if (signatureType == SignatureType.Illegal) {
LibRichErrors.rrevert(LibExchangeRichErrors.SignatureError(
LibExchangeRichErrors.SignatureErrorCodes.ILLEGAL,
hash,
@ -453,7 +473,7 @@ contract MixinSignatureValidator is
));
}
return SignatureType(signatureTypeRaw);
return signatureType;
}
/// @dev Verifies a hash and signature using logic defined by Wallet contract.