wallet: ensure wallet files are not reused across chains

1 files changed, 14 insertions, 0 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 7e694d1987..ec67c235d9 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2918,6 +2918,20 @@ bool CWallet::AttachChain(const std::shared_ptr<CWallet>& walletInstance, interf
     assert(!walletInstance->m_chain || walletInstance->m_chain == &chain);
     walletInstance->m_chain = &chain;
 
+    // Unless allowed, ensure wallet files are not reused across chains:
+    if (!gArgs.GetBoolArg("-walletcrosschain", DEFAULT_WALLETCROSSCHAIN)) {
+        WalletBatch batch(walletInstance->GetDatabase());
+        CBlockLocator locator;
+        if (batch.ReadBestBlock(locator) && locator.vHave.size() > 0 && chain.getHeight()) {
+            // Wallet is assumed to be from another chain, if genesis block in the active
+            // chain differs from the genesis block known to the wallet.
+            if (chain.getBlockHash(0) != locator.vHave.back()) {
+                error = Untranslated("Wallet files should not be reused across chains. Restart bitcoind with -walletcrosschain to override.");
+                return false;
+            }
+        }
+    }
+
     // Register wallet with validationinterface. It's done before rescan to avoid
     // missing block connections between end of rescan and validation subscribing.
     // Because of wallet lock being hold, block connection notifications are going to