Issue 160 test auction underflow

Cargo.toml

@@ -17,7 +17,7 @@ debug-assertions = true
 
 [profile.release]
 opt-level = "z"
-overflow-checks = true
+overflow-checks = true # DEV: Do not remove this check - doing so will create vulnerabilities
 debug = 0
 strip = "symbols"
 debug-assertions = false

README.md

@@ -5,7 +5,8 @@ This repository contains the smart contacts for an implementation of the Blend P
 ## Documentation
 
 To learn more about the Blend Protocol, visit the docs:
-* [Blend Docs](https://docs.blend.capital/)
+
+- [Blend Docs](https://docs.blend.capital/)
 
 ## Audits
 
@@ -30,13 +31,21 @@ make test
 The `make` command creates an optimized and un-optimized set of WASM contracts. It's recommended to use the optimized version if deploying to a network.
 
 These can be found at the path:
+
 ```
 target/wasm32-unknown-unknown/optimized
 ```
+
 For help with deployment to a network, please visit the [Blend Utils](https://github.com/blend-capital/blend-utils) repo.
 
+## Contributing
+
+Notes for contributors:
+
+- Under no circumstances should the "overflow-checks" flag be removed otherwise contract math will become unsafe
+
 ## Community Links
 
 A set of links for various things in the community. Please submit a pull request if you would like a link included.
 
-* [Blend Discord](https://discord.com/invite/a6CDBQQcjW)
+- [Blend Discord](https://discord.com/invite/a6CDBQQcjW)

test-suites/tests/test_overflow_flag.rs

@@ -0,0 +1,100 @@
+#![cfg(test)]
+use pool::Request;
+use soroban_sdk::{testutils::Address as AddressTestTrait, vec, Address, Vec};
+use test_suites::{
+    create_fixture_with_data,
+    test_fixture::{TokenIndex, SCALAR_7},
+};
+
+#[test]
+#[should_panic(expected = "Error(WasmVm, InvalidAction)")]
+fn test_backstop_donate_overflow_panics() {
+    let fixture = create_fixture_with_data(true);
+    let pool_fixture = &fixture.pools[0];
+
+    // Create a user
+    let samwise = Address::generate(&fixture.env);
+
+    fixture.tokens[TokenIndex::USDC].mint(&samwise, &(i128::MAX - 100));
+
+    // donate tokens
+    fixture
+        .backstop
+        .donate_usdc(&samwise, &pool_fixture.pool.address, &(i128::MAX - 100));
+    fixture.tokens[TokenIndex::USDC].mint(&samwise, &(500));
+    fixture.tokens[TokenIndex::USDC].burn(&fixture.backstop.address, &500);
+    fixture
+        .backstop
+        .donate_usdc(&samwise, &pool_fixture.pool.address, &201);
+}
+
+// This test ensures that an accessible underflow in the auction flow cannot be hit due to the overflow-checks flag being set
+// Without this flag set, filling an auction on the same block it's started would cause an underflow
+#[test]
+#[should_panic(expected = "Error(WasmVm, InvalidAction)")]
+fn test_auction_underflow_panics() {
+    let fixture = create_fixture_with_data(true);
+    let frodo = fixture.users.get(0).unwrap();
+    let pool_fixture = &fixture.pools[0];
+
+    // Create a user
+    let samwise = Address::generate(&fixture.env); //sam will be supplying XLM and borrowing STABLE
+
+    // Mint users tokens
+    fixture.tokens[TokenIndex::XLM].mint(&samwise, &(500_000 * SCALAR_7));
+
+    // Supply and borrow sam tokens
+    let sam_requests: Vec<Request> = vec![
+        &fixture.env,
+        Request {
+            request_type: 2,
+            address: fixture.tokens[TokenIndex::XLM].address.clone(),
+            amount: 6_000 * SCALAR_7,
+        },
+        Request {
+            request_type: 4,
+            address: fixture.tokens[TokenIndex::STABLE].address.clone(),
+            amount: 200 * 10i128.pow(6),
+        },
+    ];
+    pool_fixture
+        .pool
+        .submit(&samwise, &samwise, &samwise, &sam_requests);
+
+    //tank xlm price
+    fixture.oracle.set_price_stable(&vec![
+        &fixture.env,
+        1000_0000000, // eth
+        1_0000000,    // usdc
+        0_0000100,    // xlm
+        1_0000000,    // stable
+    ]);
+
+    // liquidate user
+    let liq_pct = 100;
+    let auction_data_2 = pool_fixture
+        .pool
+        .new_liquidation_auction(&samwise, &liq_pct);
+
+    let usdc_bid_amount = auction_data_2
+        .bid
+        .get_unchecked(fixture.tokens[TokenIndex::STABLE].address.clone());
+
+    //fill user liquidation
+    let fill_requests = vec![
+        &fixture.env,
+        Request {
+            request_type: 6,
+            address: samwise.clone(),
+            amount: 1,
+        },
+        Request {
+            request_type: 5,
+            address: fixture.tokens[TokenIndex::STABLE].address.clone(),
+            amount: usdc_bid_amount,
+        },
+    ];
+    pool_fixture
+        .pool
+        .submit(&frodo, &frodo, &frodo, &fill_requests);
+}