simplewallet: fix cold signing of split transactions

They'd be rejected as suspicious as the change goes to more
than one destination. However, split transactions will most
likely include fake zero amount change to random addresses,
so we only consider change with non zero amount for this.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index 67dacda91..9215ec821 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -3035,6 +3035,7 @@ bool simple_wallet::accept_loaded_tx(const std::function<size_t()> get_num_txes,
   size_t min_mixin = ~0;
   std::unordered_map<std::string, uint64_t> dests;
   const std::string wallet_address = m_wallet->get_account().get_public_address_str(m_wallet->testnet());
+  int first_known_non_zero_change_index = -1;
   for (size_t n = 0; n < get_num_txes(); ++n)
   {
     const tools::wallet2::tx_construction_data &cd = get_tx(n);
@@ -3069,10 +3070,15 @@ bool simple_wallet::accept_loaded_tx(const std::function<size_t()> get_num_txes,
         fail_msg_writer() << tr("Claimed change is larger than payment to the change address");
         return false;
       }
-      if (memcmp(&cd.change_dts.addr, &get_tx(0).change_dts.addr, sizeof(cd.change_dts.addr)))
+      if (cd.change_dts.amount > 0)
       {
-        fail_msg_writer() << tr("Change does to more than one address");
-        return false;
+        if (first_known_non_zero_change_index == -1)
+          first_known_non_zero_change_index = n;
+        if (memcmp(&cd.change_dts.addr, &get_tx(first_known_non_zero_change_index).change_dts.addr, sizeof(cd.change_dts.addr)))
+        {
+          fail_msg_writer() << tr("Change goes to more than one address");
+          return false;
+        }
       }
       change += cd.change_dts.amount;
       it->second -= cd.change_dts.amount;