From 185c7f08be68eec878f4b32b3a52145dd57e13bd Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Wed, 29 Mar 2017 12:33:13 -0400
Subject: [PATCH] Avoid reading the old hd master key during wallet encryption

This makes SetHDMasterKey responsible for maintinaing the CHDChain
version instead of always creating it with the latest version and
making EncryptWallet responsible for keeping the version from
changing.
---
 src/wallet/wallet.cpp | 14 ++++----------
 src/wallet/wallet.h   |  7 ++++---
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index e631c86bb2be8..42cecfb541961 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -637,12 +637,9 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
 
         // if we are using HD, replace the HD master key (seed) with a new one
         if (IsHDEnabled()) {
-            CKey key;
-            CPubKey masterPubKey = GenerateNewHDMasterKey();
-            // preserve the old chains version to not break backward compatibility
-            CHDChain oldChain = GetHDChain();
-            if (!SetHDMasterKey(masterPubKey, &oldChain))
+            if (!SetHDMasterKey(GenerateNewHDMasterKey())) {
                 return false;
+            }
         }
 
         NewKeyPool();
@@ -1308,17 +1305,14 @@ CPubKey CWallet::GenerateNewHDMasterKey()
     return pubkey;
 }
 
-bool CWallet::SetHDMasterKey(const CPubKey& pubkey, CHDChain *possibleOldChain)
+bool CWallet::SetHDMasterKey(const CPubKey& pubkey)
 {
     LOCK(cs_wallet);
     // store the keyid (hash160) together with
     // the child index counter in the database
     // as a hdchain object
     CHDChain newHdChain;
-    if (possibleOldChain) {
-        // preserve the old chains version
-        newHdChain.nVersion = possibleOldChain->nVersion;
-    }
+    newHdChain.nVersion = CanSupportFeature(FEATURE_HD_SPLIT) ? CHDChain::VERSION_HD_CHAIN_SPLIT : CHDChain::VERSION_HD_BASE;
     newHdChain.masterKeyID = pubkey.GetID();
     SetHDChain(newHdChain, false);
 
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index ccede600975db..4e7e1b57977b7 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -1056,9 +1056,10 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
     CPubKey GenerateNewHDMasterKey();
     
     /* Set the current HD master key (will reset the chain child index counters)
-       If possibleOldChain is provided, the parameters from the old chain (version)
-       will be preserved. */
-    bool SetHDMasterKey(const CPubKey& key, CHDChain *possibleOldChain = nullptr);
+       Sets the master key's version based on the current wallet version (so the
+       caller must ensure the current wallet version is correct before calling
+       this function). */
+    bool SetHDMasterKey(const CPubKey& key);
 };
 
 /** A key allocated from the key pool. */