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-rw-r--r--src/wallet/wallet.cpp19
1 files changed, 18 insertions, 1 deletions
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index bdf6d3c7a6..2775f4def3 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2534,8 +2534,25 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
return false;
}
- if (nFeeRet >= nFeeNeeded)
+ if (nFeeRet >= nFeeNeeded) {
+ // Reduce fee to only the needed amount if we have change
+ // output to increase. This prevents potential overpayment
+ // in fees if the coins selected to meet nFeeNeeded result
+ // in a transaction that requires less fee than the prior
+ // iteration.
+ // TODO: The case where nSubtractFeeFromAmount > 0 remains
+ // to be addressed because it requires returning the fee to
+ // the payees and not the change output.
+ // TODO: The case where there is no change output remains
+ // to be addressed so we avoid creating too small an output.
+ if (nFeeRet > nFeeNeeded && nChangePosInOut != -1 && nSubtractFeeFromAmount == 0) {
+ CAmount extraFeePaid = nFeeRet - nFeeNeeded;
+ vector<CTxOut>::iterator change_position = txNew.vout.begin()+nChangePosInOut;
+ change_position->nValue += extraFeePaid;
+ nFeeRet -= extraFeePaid;
+ }
break; // Done, enough fee included.
+ }
// Try to reduce change to include necessary fee
if (nChangePosInOut != -1 && nSubtractFeeFromAmount == 0) {