Fix inflated collateral (#354) (#361)

Author: piobab

Cargo.lock

@@ -1,7 +1,7 @@
 [package]
 name          = "mars-red-bank"
 description   = "A smart contract that manages asset deposit, borrowing, and liquidations"
-version       = { workspace = true }
+version       = "1.2.1"
 authors       = { workspace = true }
 edition       = { workspace = true }
 license       = { workspace = true }

contracts/oracle/wasm/tests/prop_tests.proptest-regressions

@@ -1,9 +1,9 @@
 use cosmwasm_std::{
-    entry_point, to_json_binary, Binary, Deps, DepsMut, Env, MessageInfo, Response,
+    entry_point, to_json_binary, Binary, Deps, DepsMut, Empty, Env, MessageInfo, Response,
 };
 use mars_red_bank_types::red_bank::{ExecuteMsg, InstantiateMsg, QueryMsg};
 
-use crate::{error::ContractError, execute, query};
+use crate::{error::ContractError, execute, migrations, query};
 
 #[entry_point]
 pub fn instantiate(
@@ -202,3 +202,8 @@ pub fn query(deps: Deps, env: Env, msg: QueryMsg) -> Result<Binary, ContractErro
     };
     res.map_err(Into::into)
 }
+
+#[entry_point]
+pub fn migrate(deps: DepsMut, _env: Env, _msg: Empty) -> Result<Response, ContractError> {
+    migrations::v1_2_1::migrate(deps)
+}

contracts/red-bank/Cargo.toml

@@ -29,6 +29,9 @@ pub enum ContractError {
     #[error("{0}")]
     Health(#[from] HealthError),
 
+    #[error("{0}")]
+    Version(#[from] cw2::VersionError),
+
     #[error("Price not found for asset: {denom:?}")]
     PriceNotFound {
         denom: String,
@@ -64,7 +67,7 @@ pub enum ContractError {
     #[error("Cannot have 0 as liquidity index")]
     InvalidLiquidityIndex {},
 
-    #[error("Borrow amount must be greater than 0 and less or equal available collateral (asset: {denom:?})")]
+    #[error("Borrow amount must be greater than 0 and less or equal available liquidity (asset: {denom:?})")]
     InvalidBorrowAmount {
         denom: String,
     },

contracts/red-bank/src/contract.rs

@@ -583,9 +583,15 @@ pub fn borrow(
         &borrow_market,
         env.block.time.seconds(),
     )?;
+    let debt_balance_before = get_underlying_debt_amount(
+        borrow_market.debt_total_scaled,
+        &borrow_market,
+        env.block.time.seconds(),
+    )?;
 
-    // Cannot borrow zero amount or more than available collateral
-    if borrow_amount.is_zero() || borrow_amount > collateral_balance_before {
+    // Cannot borrow zero amount or more than available liquidity
+    let available_liquidity = collateral_balance_before.checked_sub(debt_balance_before)?;
+    if borrow_amount.is_zero() || borrow_amount > available_liquidity {
         return Err(ContractError::InvalidBorrowAmount {
             denom,
         });

contracts/red-bank/src/error.rs

@@ -287,12 +287,17 @@ pub fn update_interest_rates(
     let total_debt =
         get_underlying_debt_amount(market.debt_total_scaled, market, current_timestamp)?;
 
-    let current_utilization_rate = if !total_collateral.is_zero() {
+    let mut current_utilization_rate = if !total_collateral.is_zero() {
         Decimal::from_ratio(total_debt, total_collateral)
     } else {
         Decimal::zero()
     };
 
+    // Limit utilization_rate to 100%.
+    // With the current code it should hopefully never happen that it gets calculated to more than 100%,
+    // but better be safe than sorry.
+    current_utilization_rate = current_utilization_rate.min(Decimal::one());
+
     market.update_interest_rates(current_utilization_rate)?;
 
     Ok(response.add_event(build_interests_updated_event(&market.denom, market)))

contracts/red-bank/src/execute.rs

@@ -4,6 +4,7 @@ pub mod error;
 pub mod execute;
 pub mod health;
 pub mod interest_rates;
+pub mod migrations;
 pub mod query;
 pub mod state;
 pub mod user;

contracts/red-bank/src/interest_rates.rs

@@ -0,0 +1 @@
+pub mod v1_2_1;

contracts/red-bank/src/lib.rs

@@ -0,0 +1,21 @@
+use cosmwasm_std::{DepsMut, Response};
+use cw2::{assert_contract_version, set_contract_version};
+
+use crate::{
+    error::ContractError,
+    execute::{CONTRACT_NAME, CONTRACT_VERSION},
+};
+
+const FROM_VERSION: &str = "1.2.0";
+
+pub fn migrate(deps: DepsMut) -> Result<Response, ContractError> {
+    // make sure we're migrating the correct contract and from the correct version
+    assert_contract_version(deps.storage, &format!("crates.io:{CONTRACT_NAME}"), FROM_VERSION)?;
+
+    set_contract_version(deps.storage, format!("crates.io:{CONTRACT_NAME}"), CONTRACT_VERSION)?;
+
+    Ok(Response::new()
+        .add_attribute("action", "migrate")
+        .add_attribute("from_version", FROM_VERSION)
+        .add_attribute("to_version", CONTRACT_VERSION))
+}