Set fDecryptionThoroughlyChecked based on whether crypted key checksums are valid

Change fDecryptionThoroughlyChecked to default to true so that it can
latch to false when an invalid checksum is seen. Checksums may be invalid
if the wallet does not have checksums or if the wallet became corrupted.

It is safe to default fDecryptionThoroughlyChecked to true because any
existing wallet without a checksum will set it to false. Any new or
blank wallet where encrypted keys are added will then set this to true
when the first encrypted key is generated by virtue of CheckDecryptionKey
doing that during the initial Unlock prior to keys being added.

Author: achow101

src/wallet/scriptpubkeyman.cpp

@@ -643,8 +643,13 @@ bool LegacyScriptPubKeyMan::AddKeyPubKeyInner(const CKey& key, const CPubKey &pu
     return true;
 }
 
-bool LegacyScriptPubKeyMan::LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
+bool LegacyScriptPubKeyMan::LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret, bool checksum_valid)
 {
+    // Set fDecryptionThoroughlyChecked to false when the checksum is invalid
+    if (!checksum_valid) {
+        fDecryptionThoroughlyChecked = false;
+    }
+
     return AddCryptedKeyInner(vchPubKey, vchCryptedSecret);
 }
 

src/wallet/scriptpubkeyman.h

@@ -229,7 +229,7 @@ class LegacyScriptPubKeyMan : public ScriptPubKeyMan, public FillableSigningProv
 {
 private:
     //! keeps track of whether Unlock has run a thorough check before
-    bool fDecryptionThoroughlyChecked = false;
+    bool fDecryptionThoroughlyChecked = true;
 
     using WatchOnlySet = std::set<CScript>;
     using WatchKeyMap = std::map<CKeyID, CPubKey>;
@@ -365,7 +365,7 @@ class LegacyScriptPubKeyMan : public ScriptPubKeyMan, public FillableSigningProv
     //! Adds an encrypted key to the store, and saves it to disk.
     bool AddCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
     //! Adds an encrypted key to the store, without saving it to disk (used by LoadWallet)
-    bool LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
+    bool LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret, bool checksum_valid);
     void UpdateTimeFirstKey(int64_t nCreateTime) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
     //! Adds a CScript to the store
     bool LoadCScript(const CScript& redeemScript);

src/wallet/walletdb.cpp

@@ -338,18 +338,19 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             ssValue >> vchPrivKey;
 
             // Get the checksum and check it
+            bool checksum_valid = false;
             if (!ssValue.eof()) {
                 uint256 checksum;
                 ssValue >> checksum;
-                if (Hash(vchPrivKey.begin(), vchPrivKey.end()) != checksum) {
+                if ((checksum_valid = Hash(vchPrivKey.begin(), vchPrivKey.end()) != checksum)) {
                     strErr = "Error reading wallet database: Crypted key corrupt";
                     return false;
                 }
             }
 
             wss.nCKeys++;
 
-            if (!pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadCryptedKey(vchPubKey, vchPrivKey))
+            if (!pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadCryptedKey(vchPubKey, vchPrivKey, checksum_valid))
             {
                 strErr = "Error reading wallet database: LegacyScriptPubKeyMan::LoadCryptedKey failed";
                 return false;