wallet: roll back unlocker count on decrypt failure

src/wallet/wallet2.cpp

@@ -1121,10 +1121,20 @@ wallet_keys_unlocker::wallet_keys_unlocker(wallet2 &w, const epee::wipeable_stri
   w.generate_chacha_key_from_password(*password, key);
 
   boost::lock_guard<boost::mutex> lock(lockers_lock);
-  if (lockers_per_wallet[std::addressof(w)]++ > 0)
+  wallet2* w_ptr = std::addressof(w);
+  if (lockers_per_wallet[w_ptr]++ > 0)
     return;
 
-  w.decrypt_keys(key);
+  try
+  {
+    w.decrypt_keys(key);
+  }
+  catch (...)
+  {
+    if (--lockers_per_wallet[w_ptr] == 0)
+      lockers_per_wallet.erase(w_ptr);
+    throw;
+  }
 }
 
 wallet_keys_unlocker::~wallet_keys_unlocker()

tests/unit_tests/wallet_storage.cpp

@@ -595,3 +595,26 @@ TEST(wallet_keys_unlocker, first_not_locked)
         ASSERT_TRUE(verify_wallet_privkeys(w1));
     }
 }
+
+TEST(wallet_keys_unlocker, construction_failure_rolls_back_lock_count)
+{
+    const epee::wipeable_string password("correct horse battery staple");
+    const epee::wipeable_string wrong_password("correct horse battery stable");
+
+    tools::wallet2 w;
+    w.generate("", password);
+    ASSERT_TRUE(w.is_key_encryption_enabled());
+    ASSERT_FALSE(w.is_unattended());
+    ASSERT_FALSE(verify_wallet_privkeys(w));
+
+    ASSERT_ANY_THROW({
+        tools::wallet_keys_unlocker ul(w, &wrong_password);
+    });
+    ASSERT_FALSE(verify_wallet_privkeys(w));
+
+    {
+        tools::wallet_keys_unlocker ul(w, &password);
+        ASSERT_TRUE(verify_wallet_privkeys(w));
+    }
+    ASSERT_FALSE(verify_wallet_privkeys(w));
+}