wallet: check a key image isn't already present when adding one

If it is, it points to reuse of a tx key, which isn't meant to happen.
If it does, a key image collision means that only one of those
outputs is spendable, so the wallet selects the larger amount,
unless that output was spent already.

This causes a discrepancy betewen reported received inputs and
payment total.

Since tx keys are 256 bits, this should never happen except if
done on purpose, or if a sender uses a bad PRNG.
This commit is contained in:
moneromooo-monero 2016-01-31 16:23:54 +00:00
parent 5feebb4d87
commit c7b96b91ed
No known key found for this signature in database
GPG key ID: 686F07454D6CEFC3

View file

@ -323,22 +323,59 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, uint64_
THROW_WALLET_EXCEPTION_IF(tx.vout.size() <= o, error::wallet_internal_error, "wrong out in transaction: internal index=" +
std::to_string(o) + ", total_outs=" + std::to_string(tx.vout.size()));
m_transfers.push_back(boost::value_initialized<transfer_details>());
transfer_details& td = m_transfers.back();
td.m_block_height = height;
td.m_internal_output_index = o;
td.m_global_output_index = res.o_indexes[o];
td.m_tx = tx;
td.m_spent = false;
crypto::key_image ki;
cryptonote::keypair in_ephemeral;
cryptonote::generate_key_image_helper(m_account.get_keys(), tx_pub_key, o, in_ephemeral, td.m_key_image);
cryptonote::generate_key_image_helper(m_account.get_keys(), tx_pub_key, o, in_ephemeral, ki);
THROW_WALLET_EXCEPTION_IF(in_ephemeral.pub != boost::get<cryptonote::txout_to_key>(tx.vout[o].target).key,
error::wallet_internal_error, "key_image generated ephemeral public key not matched with output_key");
m_key_images[td.m_key_image] = m_transfers.size()-1;
LOG_PRINT_L0("Received money: " << print_money(td.amount()) << ", with tx: " << get_transaction_hash(tx));
if (0 != m_callback)
m_callback->on_money_received(height, td.m_tx, td.m_internal_output_index);
auto kit = m_key_images.find(ki);
THROW_WALLET_EXCEPTION_IF(kit != m_key_images.end() && kit->second >= m_transfers.size(),
error::wallet_internal_error, std::string("Unexpected transfer index from key image: ")
+ "got " + (kit == m_key_images.end() ? "<none>" : boost::lexical_cast<std::string>(kit->second))
+ ", m_transfers.size() is " + boost::lexical_cast<std::string>(m_transfers.size()));
if (kit == m_key_images.end())
{
m_transfers.push_back(boost::value_initialized<transfer_details>());
transfer_details& td = m_transfers.back();
td.m_block_height = height;
td.m_internal_output_index = o;
td.m_global_output_index = res.o_indexes[o];
td.m_tx = tx;
td.m_key_image = ki;
td.m_spent = false;
m_key_images[td.m_key_image] = m_transfers.size()-1;
LOG_PRINT_L0("Received money: " << print_money(td.amount()) << ", with tx: " << get_transaction_hash(tx));
if (0 != m_callback)
m_callback->on_money_received(height, td.m_tx, td.m_internal_output_index);
}
else if (m_transfers[kit->second].m_spent || m_transfers[kit->second].amount() >= tx.vout[o].amount)
{
LOG_ERROR("key image " << epee::string_tools::pod_to_hex(ki)
<< " from received " << print_money(tx.vout[o].amount) << " output already exists with "
<< (m_transfers[kit->second].m_spent ? "spent" : "unspent") << " "
<< print_money(m_transfers[kit->second].amount()) << ", received output ignored");
}
else
{
LOG_ERROR("key image " << epee::string_tools::pod_to_hex(ki)
<< " from received " << print_money(tx.vout[o].amount) << " output already exists with "
<< print_money(m_transfers[kit->second].amount()) << ", replacing with new output");
// The new larger output replaced a previous smaller one
tx_money_got_in_outs -= tx.vout[o].amount;
transfer_details &td = m_transfers[kit->second];
td.m_block_height = height;
td.m_internal_output_index = o;
td.m_global_output_index = res.o_indexes[o];
td.m_tx = tx;
THROW_WALLET_EXCEPTION_IF(td.m_key_image != ki, error::wallet_internal_error, "Inconsistent key images");
THROW_WALLET_EXCEPTION_IF(td.m_spent, error::wallet_internal_error, "Inconsistent spent status");
LOG_PRINT_L0("Received money: " << print_money(td.amount()) << ", with tx: " << get_transaction_hash(tx));
if (0 != m_callback)
m_callback->on_money_received(height, td.m_tx, td.m_internal_output_index);
}
}
}
}