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terra/token_bridge: reentrancy protection 

commit-id:2c0bdfaf
This commit is contained in:
Csongor Kiss 2022-01-20 17:50:37 +00:00
parent 83b97bedb8
commit 52562cacb0
1 changed files with 17 additions and 0 deletions
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17
terra/contracts/token-bridge/src/contract.rs
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@ -122,6 +122,9 @@ const WRAPPED_ASSET_UPDATING: &str = "updating";
#[cfg_attr(not(feature = "library"), entry_point)] #[cfg_attr(not(feature = "library"), entry_point)]
pub fn migrate(deps: DepsMut, _env: Env, _msg: MigrateMsg) -> StdResult<Response> { pub fn migrate(deps: DepsMut, _env: Env, _msg: MigrateMsg) -> StdResult<Response> {
// Clear out this just to be safe
wrapped_transfer_tmp(deps.storage).remove();
let mut bucket = wrapped_asset_address(deps.storage); let mut bucket = wrapped_asset_address(deps.storage);
// Remove registered asset with old code ID. // Remove registered asset with old code ID.
@ -175,7 +178,12 @@ pub fn instantiate(
#[cfg_attr(not(feature = "library"), entry_point)] #[cfg_attr(not(feature = "library"), entry_point)]
pub fn reply(deps: DepsMut, env: Env, _msg: Reply) -> StdResult<Response> { pub fn reply(deps: DepsMut, env: Env, _msg: Reply) -> StdResult<Response> {
let cfg = config_read(deps.storage).load()?; let cfg = config_read(deps.storage).load()?;
let state = wrapped_transfer_tmp(deps.storage).load()?; let state = wrapped_transfer_tmp(deps.storage).load()?;
// NOTE: Reentrancy protection. See note in `handle_initiate_transfer_token`
// for why this is necessary.
wrapped_transfer_tmp(deps.storage).remove();
let mut info = TransferInfo::deserialize(&state.message)?; let mut info = TransferInfo::deserialize(&state.message)?;
// Fetch CW20 Balance post-transfer. // Fetch CW20 Balance post-transfer.
@ -1018,6 +1026,15 @@ fn handle_initiate_transfer_token(
})?, })?,
}))?; }))?;
// NOTE: Reentrancy protection. It is crucial that there's no
// ongoing transfer in progress here, otherwise we would override
// its state. This could happen if the asset's TransferFrom handler
// sends us an InitiateTransfer message, which would be executed
// before the reply handler due the the depth-first semantics of
// message execution. A simple protection mechanism is to require
// that there's no execution in progress. The reply handler takes
// care of clearing out this temporary storage when done.
assert!(wrapped_transfer_tmp(deps.storage).load().is_err());
// Wrap up state to be captured by the submessage reply. // Wrap up state to be captured by the submessage reply.
wrapped_transfer_tmp(deps.storage).save(&TransferState { wrapped_transfer_tmp(deps.storage).save(&TransferState {
previous_balance: balance.balance.to_string(), previous_balance: balance.balance.to_string(),