Overflow checker in initialize

src/lib.rs

@@ -412,12 +412,12 @@ pub mod pallet {
 			let incoming_rewards: BalanceOf<T> = rewards
 				.iter()
 				.fold(0u32.into(), |acc: BalanceOf<T>, (_, _, reward)| {
-					acc + *reward
+					acc.saturating_add(*reward)
 				});
 
 			// Ensure we dont go over funds
 			ensure!(
-				current_initialized_rewards + incoming_rewards <= Self::pot(),
+				current_initialized_rewards.saturating_add(incoming_rewards) <= Self::pot(),
 				Error::<T>::BatchBeyondFundPot
 			);
 
@@ -470,6 +470,8 @@ pub mod pallet {
 					claimed_reward: initial_payment,
 				};
 
+				// It should be safe not to use saturating_add here
+				// as we already checked before that these rewards do not overflow existing ones
 				current_initialized_rewards += *reward - initial_payment;
 				total_contributors += 1;
 
@@ -478,6 +480,8 @@ pub mod pallet {
 						// the native account has already some rewards in, we add the new ones
 						AccountsPayable::<T>::insert(
 							native_account,
+							// It should be safe not to use saturating_add here
+							// as we already checked before that these rewards do not overflow existing ones
 							RewardInfo {
 								total_reward: inserted_reward_info.total_reward
 									+ reward_info.total_reward,

src/tests.rs

@@ -877,3 +877,26 @@ fn test_initialization_errors() {
 		);
 	});
 }
+
+#[test]
+fn test_assert_we_cannot_overflow_at_init() {
+	empty().execute_with(|| {
+		// The init relay block gets inserted
+		roll_to(2);
+		assert_ok!(Crowdloan::initialize_reward_vec(
+			Origin::root(),
+			vec![([1u8; 32].into(), Some(1), 500u32.into()),]
+		));
+		// This should overflow
+		assert_noop!(
+			Crowdloan::initialize_reward_vec(
+				Origin::root(),
+				vec![
+					([2u8; 32].into(), Some(2), 1),
+					([3u8; 32].into(), Some(3), u128::MAX),
+				]
+			),
+			Error::<Test>::BatchBeyondFundPot
+		);
+	});
+}