Merge #18192: Bugfix: Wallet: Safely deal with change in the address book

b5795a788639305bab86a8b3f6b75d6ce81be083 Wallet: Add warning comments and assert to CWallet::DelAddressBook (Luke Dashjr)
6d2905f57aaeb3ec3b63d31043f7673ca10003f2 Wallet: Avoid unnecessary/redundant m_address_book lookups (Luke Dashjr)
c751d886f499257627b308b11ffaa51c22db6cc0 Wallet: Avoid treating change-in-the-addressbook as non-change everywhere (Luke Dashjr)
8e64b8c84bcbd63caea06f3af087af1f0609eaf5 Wallet: New FindAddressBookEntry method to filter out change entries (and skip ->second everywhere) (Luke Dashjr)
65b6bdc2b164343ec3cc3d32a0297daff9e24fec Wallet: Add CAddressBookData::IsChange which returns true iff label has never been set (Luke Dashjr)
144b2f85da4d51bf7d72b987888ddcaf5b429eed Wallet: Require usage of new CAddressBookData::setLabel to change label (Luke Dashjr)
b86cd155f6f661052042048aa7cfc2a397afe4f7 scripted-diff: Wallet: Rename mapAddressBook to m_address_book (Luke Dashjr)

Pull request description:

  In many places, our code assumes that presence in the address book indicates a non-change key, and absence of an entry in mapAddressBook indicates change.

  This no longer holds true after #13756 (first released in 0.19) since it added a "used" DestData populated even for change addresses. Only avoid-reuse wallets should be affected by this issue.

  Thankfully, populating DestData does not write a label to the database, so we can retroactively fix this (so long as the user didn't see the change address and manually assign it a real label).

  Fixing it is accomplished by:

  * Adding a new bool to CAddressBookData to track if the label has ever been assigned, either by loading one from the database, or by assigning one at runtime.
  * `CAddressBookData::IsChange` and `CWallet::FindAddressBookEntry` are new methods to assist in excluding change from code that doesn't expect to see them.
  * For safety in merging, `CAddressBookData::name` has been made read-only (the actual data is stored in `m_label`, a new private member, and can be changed only with `setLabel` which updates the `m_change` flag), and `mapAddressBook` has been renamed to `m_address_book` (to force old code to be rebased to compile).

  A final commit also does some minor optimisation, avoiding redundant lookups in `m_address_book` when we already have a pointer to the `CAddressBookData`.

ACKs for top commit:
  ryanofsky:
    Code review ACK b5795a788639305bab86a8b3f6b75d6ce81be083. Pretty clever and nicely implemented fix!
  jonatack:
    ACK b5795a788639305bab86a8b3f6b75d6ce81be083 nice improvements -- code review, built/ran tests rebased on current master ff53433fe4ed06893d7c4 and tested manually with rpc/cli
  jnewbery:
    Good fix. utACK b5795a788.

Tree-SHA512: 40525185a0bcc1723f602243c269499ec86ecb298fecb5ef24d626bbdd5e3efece86cdb1084ad7eebf7eeaf251db4a6e056bcd25bc8457b417fcbb53d032ebf0

1 files changed, 32 insertions, 15 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index bc9f84a11d..9ee3bbd038 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1242,8 +1242,9 @@ bool CWallet::IsChange(const CScript& script) const
             return true;
 
         LOCK(cs_wallet);
-        if (!mapAddressBook.count(address))
+        if (!FindAddressBookEntry(address)) {
             return true;
+        }
     }
     return false;
 }
@@ -3196,11 +3197,11 @@ bool CWallet::SetAddressBookWithDB(WalletBatch& batch, const CTxDestination& add
     bool fUpdated = false;
     {
         LOCK(cs_wallet);
-        std::map<CTxDestination, CAddressBookData>::iterator mi = mapAddressBook.find(address);
-        fUpdated = mi != mapAddressBook.end();
-        mapAddressBook[address].name = strName;
+        std::map<CTxDestination, CAddressBookData>::iterator mi = m_address_book.find(address);
+        fUpdated = (mi != m_address_book.end() && !mi->second.IsChange());
+        m_address_book[address].SetLabel(strName);
         if (!strPurpose.empty()) /* update purpose only if requested */
-            mapAddressBook[address].purpose = strPurpose;
+            m_address_book[address].purpose = strPurpose;
     }
     NotifyAddressBookChanged(this, address, strName, IsMine(address) != ISMINE_NO,
                              strPurpose, (fUpdated ? CT_UPDATED : CT_NEW) );
@@ -3217,16 +3218,21 @@ bool CWallet::SetAddressBook(const CTxDestination& address, const std::string& s
 
 bool CWallet::DelAddressBook(const CTxDestination& address)
 {
+    // If we want to delete receiving addresses, we need to take care that DestData "used" (and possibly newer DestData) gets preserved (and the "deleted" address transformed into a change entry instead of actually being deleted)
+    // NOTE: This isn't a problem for sending addresses because they never have any DestData yet!
+    // When adding new DestData, it should be considered here whether to retain or delete it (or move it?).
+    assert(!IsMine(address));
+
     {
         LOCK(cs_wallet);
 
         // Delete destdata tuples associated with address
         std::string strAddress = EncodeDestination(address);
-        for (const std::pair<const std::string, std::string> &item : mapAddressBook[address].destdata)
+        for (const std::pair<const std::string, std::string> &item : m_address_book[address].destdata)
         {
             WalletBatch(*database).EraseDestData(strAddress, item.first);
         }
-        mapAddressBook.erase(address);
+        m_address_book.erase(address);
     }
 
     NotifyAddressBookChanged(this, address, "", IsMine(address) != ISMINE_NO, "", CT_DELETED);
@@ -3462,8 +3468,9 @@ std::set<CTxDestination> CWallet::GetLabelAddresses(const std::string& label) co
 {
     LOCK(cs_wallet);
     std::set<CTxDestination> result;
-    for (const std::pair<const CTxDestination, CAddressBookData>& item : mapAddressBook)
+    for (const std::pair<const CTxDestination, CAddressBookData>& item : m_address_book)
     {
+        if (item.second.IsChange()) continue;
         const CTxDestination& address = item.first;
         const std::string& strName = item.second.name;
         if (strName == label)
@@ -3666,26 +3673,26 @@ bool CWallet::AddDestData(WalletBatch& batch, const CTxDestination &dest, const
     if (boost::get<CNoDestination>(&dest))
         return false;
 
-    mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
+    m_address_book[dest].destdata.insert(std::make_pair(key, value));
     return batch.WriteDestData(EncodeDestination(dest), key, value);
 }
 
 bool CWallet::EraseDestData(WalletBatch& batch, const CTxDestination &dest, const std::string &key)
 {
-    if (!mapAddressBook[dest].destdata.erase(key))
+    if (!m_address_book[dest].destdata.erase(key))
         return false;
     return batch.EraseDestData(EncodeDestination(dest), key);
 }
 
 void CWallet::LoadDestData(const CTxDestination &dest, const std::string &key, const std::string &value)
 {
-    mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
+    m_address_book[dest].destdata.insert(std::make_pair(key, value));
 }
 
 bool CWallet::GetDestData(const CTxDestination &dest, const std::string &key, std::string *value) const
 {
-    std::map<CTxDestination, CAddressBookData>::const_iterator i = mapAddressBook.find(dest);
-    if(i != mapAddressBook.end())
+    std::map<CTxDestination, CAddressBookData>::const_iterator i = m_address_book.find(dest);
+    if(i != m_address_book.end())
     {
         CAddressBookData::StringMap::const_iterator j = i->second.destdata.find(key);
         if(j != i->second.destdata.end())
@@ -3701,7 +3708,7 @@ bool CWallet::GetDestData(const CTxDestination &dest, const std::string &key, st
 std::vector<std::string> CWallet::GetDestValues(const std::string& prefix) const
 {
     std::vector<std::string> values;
-    for (const auto& address : mapAddressBook) {
+    for (const auto& address : m_address_book) {
         for (const auto& data : address.second.destdata) {
             if (!data.first.compare(0, prefix.size(), prefix)) {
                 values.emplace_back(data.second);
@@ -4103,12 +4110,22 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain,
     {
         walletInstance->WalletLogPrintf("setKeyPool.size() = %u\n",      walletInstance->GetKeyPoolSize());
         walletInstance->WalletLogPrintf("mapWallet.size() = %u\n",       walletInstance->mapWallet.size());
-        walletInstance->WalletLogPrintf("mapAddressBook.size() = %u\n",  walletInstance->mapAddressBook.size());
+        walletInstance->WalletLogPrintf("m_address_book.size() = %u\n",  walletInstance->m_address_book.size());
     }
 
     return walletInstance;
 }
 
+const CAddressBookData* CWallet::FindAddressBookEntry(const CTxDestination& dest, bool allow_change) const
+{
+    const auto& address_book_it = m_address_book.find(dest);
+    if (address_book_it == m_address_book.end()) return nullptr;
+    if ((!allow_change) && address_book_it->second.IsChange()) {
+        return nullptr;
+    }
+    return &address_book_it->second;
+}
+
 void CWallet::postInitProcess()
 {
     auto locked_chain = chain().lock();