- Added a safe addition helper function, safe_add, to the Fund Admi…

…n Pallet to mitigate risks from arithmetic overflow. This function checks if the addition of two numbers results in an overflow and, if so, throws the `ArithmeticOverflow` error. This check has been incorporated into the `do_calculate_drawdown_total_amount` and `do_calculate_revenue_total_amount` functions to ensure safe addition operation and provide user feedback.

- Defined a new `ArithmeticOverflow` error in the Fund Admin Pallet to provide feedback for operations that can potentially cause arithmetic overflow. This helps increase the robustness of our numeric operations.
- Introduced two new test cases `replicate_overflow_for_a_drawdown_submission` and `replicate_overflow_for_a_revenue_submission` in the Fund Admin Pallet test suite to ensure accurate arithmetic overflow detection. These tests validate that the system correctly rejects drawdown and revenue submissions which would result in arithmetic overflow conditions. This expands the coverage of our testing and ensures the safe operation of financial transactions.

pallets/fund-admin/src/functions.rs

@@ -2008,13 +2008,8 @@ impl<T: Config> Pallet<T> {
 
 		// Create revenue transaction id
 		let revenue_transaction_id =
-			(revenue_id, job_eligible_id, project_id, timestamp).using_encoded(blake2_256);
-
-		// Ensure revenue transaction id doesn't exist
-		ensure!(
-			!RevenueTransactionsInfo::<T>::contains_key(revenue_transaction_id),
-			Error::<T>::RevenueTransactionIdAlreadyExists
-		);
+			(revenue_id, revenue_amount, job_eligible_id, project_id, timestamp)
+				.using_encoded(blake2_256);
 
 		// Create revenue transaction data
 		let revenue_transaction_data = RevenueTransactionData {
@@ -3125,6 +3120,11 @@ impl<T: Config> Pallet<T> {
 		Ok(())
 	}
 
+	fn safe_add(a: u64, b: u64) -> DispatchResult {
+		a.checked_add(b).ok_or_else(|| Error::<T>::ArithmeticOverflow)?;
+		Ok(())
+	}
+
 	fn do_calculate_drawdown_total_amount(
 		project_id: [u8; 32],
 		drawdown_id: [u8; 32],
@@ -3145,6 +3145,8 @@ impl<T: Config> Pallet<T> {
 				// Get transaction data
 				let transaction_data = TransactionsInfo::<T>::get(transaction_id)
 					.ok_or(Error::<T>::TransactionNotFound)?;
+				// Check arithmetic overflow
+				Self::safe_add(drawdown_total_amount, transaction_data.amount)?;
 
 				// Add transaction amount to drawdown total amount
 				drawdown_total_amount += transaction_data.amount;
@@ -3298,6 +3300,9 @@ impl<T: Config> Pallet<T> {
 					RevenueTransactionsInfo::<T>::get(revenue_transaction_id)
 						.ok_or(Error::<T>::RevenueTransactionNotFound)?;
 
+				// Check arithmetic overflow
+				Self::safe_add(revenue_total_amount, revenue_transaction_data.amount)?;
+
 				// Add revenue transaction amount to revenue total amount
 				revenue_total_amount += revenue_transaction_data.amount;
 			}

pallets/fund-admin/src/lib.rs

@@ -694,6 +694,8 @@ pub mod pallet {
 		AdminHasNoFreeBalance,
 		/// Administrator account has insuficiente balance to register a new user
 		InsufficientFundsToTransfer,
+		// Arithmetic addition overflow
+		ArithmeticOverflow,
 	}
 
 	// E X T R I N S I C S

pallets/fund-admin/src/mock.rs

@@ -152,6 +152,7 @@ impl pallet_rbac::Config for Test {
 	type MaxRolesPerUser = MaxRolesPerUser;
 	type MaxUsersPerRole = MaxUsersPerRole;
 	type RemoveOrigin = EnsureRoot<Self::AccountId>;
+	type WeightInfo = ();
 }
 
 // Build genesis storage according to the mock runtime.

pallets/fund-admin/src/tests.rs

@@ -4174,6 +4174,50 @@ fn drawdowns_a_user_submits_a_drawdown_for_approval_works() {
 	});
 }
 
+#[test]
+fn replicate_overflow_for_a_drawdown_submission() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(make_default_full_project());
+		let project_id = ProjectsInfo::<Test>::iter_keys().next().unwrap();
+
+		let drawdown_id = get_drawdown_id(project_id, DrawdownType::EB5, 1);
+		let expenditure_id = get_budget_expenditure_id(
+			project_id,
+			make_field_name("Expenditure Test 1"),
+			ExpenditureType::HardCost,
+		);
+
+		let transaction_data =
+			make_transaction(Some(expenditure_id), Some(1000), CUDAction::Create, None);
+
+		assert_ok!(FundAdmin::submit_drawdown(
+			RuntimeOrigin::signed(2),
+			project_id,
+			drawdown_id,
+			Some(transaction_data),
+			false,
+		));
+
+		let second_transaction_data = make_transaction(
+			Some(expenditure_id),
+			Some(18446744073709551615),
+			CUDAction::Create,
+			None,
+		);
+
+		assert_noop!(
+			FundAdmin::submit_drawdown(
+				RuntimeOrigin::signed(2),
+				project_id,
+				drawdown_id,
+				Some(second_transaction_data),
+				true,
+			),
+			Error::<Test>::ArithmeticOverflow
+		);
+	});
+}
+
 #[test]
 fn drawdowns_a_user_submits_a_draft_drawdown_for_approval_works() {
 	new_test_ext().execute_with(|| {
@@ -5790,6 +5834,46 @@ fn revenues_after_a_revenue_is_submitted_the_next_one_is_generated_automaticaly_
 	});
 }
 
+#[test]
+fn replicate_overflow_for_a_revenue_submission() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(make_default_full_project());
+		let project_id = ProjectsInfo::<Test>::iter_keys().next().unwrap();
+
+		let revenue_id = get_revenue_id(project_id, 1);
+		let job_eligible_id = get_job_eligible_id(project_id, make_field_name("Job Eligible Test"));
+
+		let revenue_transaction_data =
+			make_revenue_transaction(Some(job_eligible_id), Some(10000), CUDAction::Create, None);
+
+		assert_ok!(FundAdmin::submit_revenue(
+			RuntimeOrigin::signed(2),
+			project_id,
+			revenue_id,
+			Some(revenue_transaction_data),
+			false,
+		));
+
+		let second_revenue_transaction_data = make_revenue_transaction(
+			Some(job_eligible_id),
+			Some(18446744073709551615),
+			CUDAction::Create,
+			None,
+		);
+
+		assert_noop!(
+			FundAdmin::submit_revenue(
+				RuntimeOrigin::signed(2),
+				project_id,
+				revenue_id,
+				Some(second_revenue_transaction_data),
+				true,
+			),
+			Error::<Test>::ArithmeticOverflow
+		);
+	});
+}
+
 #[test]
 fn revenues_an_administrator_rejects_a_given_revenue_works() {
 	new_test_ext().execute_with(|| {