OmnichainCallbackHandlerFacet Manual Review Findings

OCH-01M: Potentially Improper Callback Handling

Type	Severity	Location
Logical Fault		OmnichainCallbackHandlerFacet.sol:L36-L40

Description:

The OmnichainCallbackHandlerFacet::omnichainCallback function will not fail even if a particular callback has been consumed as the default state of the CallbackOperation enum is the IS_DATAPOINT_ADMIN_RESPONSE.

Impact:

The consumption of callback handler data is not performed properly due to the enum depicting a single state, permitting a particular rid to be reused.

Example:

Copy
35(OmnichainSupportStorage.CallbackOperation op, bytes memory opData) = ossLayout.useCallbackHandlerData(rid);
36if (op == OmnichainSupportStorage.CallbackOperation.IS_DATAPOINT_ADMIN_RESPONSE) {
37    _approveOmnichainDataManagerCallback(opData, data);
38} else {

Recommendation:

We advise a new state to be introduced to the enum in its first slot, properly preventing a consumed callback from being repeated.

Alleviation (c6b23c23d8bcd8cce85049ad959cbd711a37126b):

A new state to the CallbackOperation enum was introduced at the OmnichainSupportStorage contract level, alleviating this exhibit.