wallet: do not allow loading descriptor with an invalid ID

If the computed descriptor's ID doesn't match the wallet's
DB spkm ID, return early from the loading process to prevent
DB data from being modified in any post-loading procedure
(e.g 'TopUp' updates the descriptor's data).

Author: furszy

src/wallet/test/walletload_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <wallet/test/util.h>
 #include <wallet/wallet.h>
+#include <test/util/logging.h>
 #include <test/util/setup_common.h>
 
 #include <boost/test/unit_test.hpp>
@@ -32,7 +33,7 @@ class DummyDescriptor final : public Descriptor {
     void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const override {}
 };
 
-BOOST_FIXTURE_TEST_CASE(wallet_load_unknown_descriptor, TestingSetup)
+BOOST_FIXTURE_TEST_CASE(wallet_load_descriptors, TestingSetup)
 {
     std::unique_ptr<WalletDatabase> database = CreateMockableWalletDatabase();
     {
@@ -49,6 +50,33 @@ BOOST_FIXTURE_TEST_CASE(wallet_load_unknown_descriptor, TestingSetup)
         const std::shared_ptr<CWallet> wallet(new CWallet(m_node.chain.get(), "", std::move(database)));
         BOOST_CHECK_EQUAL(wallet->LoadWallet(), DBErrors::UNKNOWN_DESCRIPTOR);
     }
+
+    // Test 2
+    // Now write a valid descriptor with an invalid ID.
+    // As the software produces another ID for the descriptor, the loading process must be aborted.
+    database = CreateMockableWalletDatabase();
+
+    // Verify the error
+    bool found = false;
+    DebugLogHelper logHelper("The descriptor ID calculated by the wallet differs from the one in DB", [&](const std::string* s) {
+        found = true;
+        return false;
+    });
+
+    {
+        // Write valid descriptor with invalid ID
+        WalletBatch batch(*database, false);
+        std::string desc = "wpkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)#cjjspncu";
+        WalletDescriptor wallet_descriptor(std::make_shared<DummyDescriptor>(desc), 0, 0, 0, 0);
+        BOOST_CHECK(batch.WriteDescriptor(uint256::ONE, wallet_descriptor));
+    }
+
+    {
+        // Now try to load the wallet and verify the error.
+        const std::shared_ptr<CWallet> wallet(new CWallet(m_node.chain.get(), "", std::move(database)));
+        BOOST_CHECK_EQUAL(wallet->LoadWallet(), DBErrors::CORRUPT);
+        BOOST_CHECK(found); // The error must be logged
+    }
 }
 
 bool HasAnyRecordOfType(WalletDatabase& db, const std::string& key)

src/wallet/walletdb.cpp

@@ -803,6 +803,12 @@ static DBErrors LoadDescriptorWalletRecords(CWallet* pwallet, DatabaseBatch& bat
         }
         pwallet->LoadDescriptorScriptPubKeyMan(id, desc);
 
+        // Prior to doing anything with this spkm, verify ID compatibility
+        if (id != pwallet->GetDescriptorScriptPubKeyMan(desc)->GetID()) {
+            strErr = "The descriptor ID calculated by the wallet differs from the one in DB";
+            return DBErrors::CORRUPT;
+        }
+
         DescriptorCache cache;
 
         // Get key cache for this descriptor