std::pair<bool, std::string> STTx::checkMultiSign () const
{
// Make sure the MultiSigners are present. Otherwise they are not
// attempting multi-signing and we just have a bad SigningPubKey.
if (!isFieldPresent (sfSigners))
return {false, "Empty SigningPubKey."};
// We don't allow both an sfSigners and an sfTxnSignature. Both fields
// being present would indicate that the transaction is signed both ways.
if (isFieldPresent (sfTxnSignature))
return {false, "Cannot both single- and multi-sign."};
STArray const& signers {getFieldArray (sfSigners)};
// There are well known bounds that the number of signers must be within.
if (signers.size() < minMultiSigners || signers.size() > maxMultiSigners)
return {false, "Invalid Signers array size."};
// We can ease the computational load inside the loop a bit by
// pre-constructing part of the data that we hash. Fill a Serializer
// with the stuff that stays constant from signature to signature.
Serializer const dataStart {startMultiSigningData (*this)};
// We also use the sfAccount field inside the loop. Get it once.
auto const txnAccountID = getAccountID (sfAccount);
// Determine whether signatures must be full canonical.
bool const fullyCanonical = (getFlags() & tfFullyCanonicalSig);
// Signers must be in sorted order by AccountID.
AccountID lastAccountID (beast::zero);
for (auto const& signer : signers)
{
auto const accountID = signer.getAccountID (sfAccount);
// The account owner may not multisign for themselves.
if (accountID == txnAccountID)
return {false, "Invalid multisigner."};
// No duplicate signers allowed.
if (lastAccountID == accountID)
return {false, "Duplicate Signers not allowed."};
// Accounts must be in order by account ID. No duplicates allowed.
if (lastAccountID > accountID)
return {false, "Unsorted Signers array."};
// The next signature must be greater than this one.
lastAccountID = accountID;
// Verify the signature.
bool validSig = false;
try
{
Serializer s = dataStart;
finishMultiSigningData (accountID, s);
auto spk = signer.getFieldVL (sfSigningPubKey);
if (publicKeyType (makeSlice(spk)))
{
Blob const signature =
signer.getFieldVL (sfTxnSignature);
validSig = verify (
PublicKey (makeSlice(spk)),
s.slice(),
makeSlice(signature),
fullyCanonical);
}
}
catch (std::exception const&)
{
// We assume any problem lies with the signature.
validSig = false;
}
if (!validSig)
return {false, std::string("Invalid signature on account ") +
toBase58(accountID) + "."};
}
// All signatures verified.
return {true, ""};
}
bool
STTx::checkMultiSign () const
{
// Make sure the MultiSigners are present. Otherwise they are not
// attempting multi-signing and we just have a bad SigningPubKey.
if (!isFieldPresent (sfSigners))
return false;
STArray const& signers {getFieldArray (sfSigners)};
// There are well known bounds that the number of signers must be within.
if (signers.size() < minMultiSigners || signers.size() > maxMultiSigners)
return false;
// We can ease the computational load inside the loop a bit by
// pre-constructing part of the data that we hash. Fill a Serializer
// with the stuff that stays constant from signature to signature.
Serializer const dataStart {startMultiSigningData (*this)};
// We also use the sfAccount field inside the loop. Get it once.
auto const txnAccountID = getAccountID (sfAccount);
// Determine whether signatures must be full canonical.
ECDSA const fullyCanonical = (getFlags() & tfFullyCanonicalSig)
? ECDSA::strict
: ECDSA::not_strict;
// Signers must be in sorted order by AccountID.
AccountID lastAccountID (beast::zero);
for (auto const& signer : signers)
{
auto const accountID = signer.getAccountID (sfAccount);
// The account owner may not multisign for themselves.
if (accountID == txnAccountID)
return false;
// Accounts must be in order by account ID. No duplicates allowed.
if (lastAccountID >= accountID)
return false;
// The next signature must be greater than this one.
lastAccountID = accountID;
// Verify the signature.
bool validSig = false;
try
{
Serializer s = dataStart;
finishMultiSigningData (accountID, s);
RippleAddress const pubKey =
RippleAddress::createAccountPublic (
signer.getFieldVL (sfSigningPubKey));
Blob const signature = signer.getFieldVL (sfTxnSignature);
validSig = pubKey.accountPublicVerify (
s.getData(), signature, fullyCanonical);
}
catch (...)
{
// We assume any problem lies with the signature.
validSig = false;
}
if (!validSig)
return false;
}
// All signatures verified.
return true;
}
