From 7414733beac92ce8ba365def592d0363fb24872c Mon Sep 17 00:00:00 2001
From: Matt Corallo <matt@bluematt.me>
Date: Sun, 10 Jul 2011 16:07:22 +0200
Subject: [PATCH] Make an invalid addrIncoming so that old clients crash.

This prevents old clients from opening, and thus corrupting
or otherwise causing harm to encrypted wallets.
---
 src/db.cpp     |  2 --
 src/main.cpp   |  1 -
 src/main.h     |  1 -
 src/wallet.cpp | 15 +++++++++++++++
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/db.cpp b/src/db.cpp
index e639a347..ebe7e3a8 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -828,7 +828,6 @@ bool CWalletDB::LoadWallet(CWallet* pwallet)
                 if (strKey == "fGenerateBitcoins")  ssValue >> fGenerateBitcoins;
 #endif
                 if (strKey == "nTransactionFee")    ssValue >> nTransactionFee;
-                if (strKey == "addrIncoming")       ssValue >> addrIncoming;
                 if (strKey == "fLimitProcessors")   ssValue >> fLimitProcessors;
                 if (strKey == "nLimitProcessors")   ssValue >> nLimitProcessors;
                 if (strKey == "fMinimizeToTray")    ssValue >> fMinimizeToTray;
@@ -847,7 +846,6 @@ bool CWalletDB::LoadWallet(CWallet* pwallet)
     printf("nFileVersion = %d\n", nFileVersion);
     printf("fGenerateBitcoins = %d\n", fGenerateBitcoins);
     printf("nTransactionFee = %"PRI64d"\n", nTransactionFee);
-    printf("addrIncoming = %s\n", addrIncoming.ToString().c_str());
     printf("fMinimizeToTray = %d\n", fMinimizeToTray);
     printf("fMinimizeOnClose = %d\n", fMinimizeOnClose);
     printf("fUseProxy = %d\n", fUseProxy);
diff --git a/src/main.cpp b/src/main.cpp
index 53cdab17..6e973493 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -55,7 +55,6 @@ int64 nHPSTimerStart;
 // Settings
 int fGenerateBitcoins = false;
 int64 nTransactionFee = 0;
-CAddress addrIncoming;
 int fLimitProcessors = false;
 int nLimitProcessors = 1;
 int fMinimizeToTray = true;
diff --git a/src/main.h b/src/main.h
index aa74ac5a..0757ef50 100644
--- a/src/main.h
+++ b/src/main.h
@@ -68,7 +68,6 @@ extern std::set<CWallet*> setpwalletRegistered;
 // Settings
 extern int fGenerateBitcoins;
 extern int64 nTransactionFee;
-extern CAddress addrIncoming;
 extern int fLimitProcessors;
 extern int nLimitProcessors;
 extern int fMinimizeToTray;
diff --git a/src/wallet.cpp b/src/wallet.cpp
index 9f3701a8..93313e7b 100644
--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -108,6 +108,19 @@ bool CWallet::ChangeWalletPassphrase(const string& strOldWalletPassphrase, const
     return false;
 }
 
+
+// This class implements an addrIncoming entry that causes pre-0.4
+// clients to crash on startup if reading a private-key-encrypted wallet.
+class CCorruptAddress
+{
+public:
+    IMPLEMENT_SERIALIZE
+    (
+        if (nType & SER_DISK)
+            READWRITE(nVersion);
+    )
+};
+
 bool CWallet::EncryptWallet(const string& strWalletPassphrase)
 {
     CRITICAL_BLOCK(cs_mapPubKeys)
@@ -166,6 +179,8 @@ bool CWallet::EncryptWallet(const string& strWalletPassphrase)
 
         if (fFileBacked)
         {
+            CCorruptAddress corruptAddress;
+            pwalletdbEncryption->WriteSetting("addrIncoming", corruptAddress);
             if (!pwalletdbEncryption->TxnCommit())
                 exit(1); //We now have keys encrypted in memory, but no on disk...die to avoid confusion and let the user reload their unencrypted wallet.