No longer ever reuse keypool indexes

This fixes an issue where you could reserve a keypool entry, then
top up the keypool, writing out a new key at the given index, then
return they key from the pool. This isnt likely to cause issues,
but given there is no reason to ever re-use keypool indexes
(they're 64 bits...), best to avoid it alltogether.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 06937566b0..574fd8710d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -701,6 +701,7 @@ private:
 
     std::set<int64_t> setInternalKeyPool;
     std::set<int64_t> setExternalKeyPool;
+    int64_t m_max_keypool_index;
 
     int64_t nTimeFirstKey;
 
@@ -743,13 +744,14 @@ public:
         }
     }
 
-    void LoadKeyPool(int nIndex, const CKeyPool &keypool)
+    void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool)
     {
         if (keypool.fInternal) {
             setInternalKeyPool.insert(nIndex);
         } else {
             setExternalKeyPool.insert(nIndex);
         }
+        m_max_keypool_index = std::max(m_max_keypool_index, nIndex);
 
         // If no metadata exists yet, create a default with the pool key's
         // creation time. Note that this may be overwritten by actually
@@ -795,6 +797,7 @@ public:
         nAccountingEntryNumber = 0;
         nNextResend = 0;
         nLastResend = 0;
+        m_max_keypool_index = 0;
         nTimeFirstKey = 0;
         fBroadcastTransactions = false;
         nRelockTime = 0;