LayerZeroRebaseTokenUpgradeable Code Style Findings

LZR-01C: Cross-Chain Amount Truncation

Type	Severity	Location
Code Style		LayerZeroRebaseTokenUpgradeable.sol:L154, L159

Description:

The SendToChain event's amount emitted during the LayerZeroRebaseTokenUpgradeable::_send function may not be equal to the actual amount transferred by the function due to potential truncation in the LayerZeroRebaseTokenUpgradeable::_debitFrom function.

Impact:

In contrast to the EIP-20 related exhibit, this one relates to a custom event and thus is of minimal impact.

Example:

Copy
153Message memory message = Message({
154    shares: _debitFrom(from, dstChainId, toAddress, amount),
155    rebaseIndex: rebaseIndex(),
156    nonce: _rebaseNonce()
157});
158
159emit SendToChain(dstChainId, from, toAddress, amount);

Recommendation:

We advise the amount value emitted in the SendToChain event within LayerZeroRebaseTokenUpgradeable::_send to be set to the message.shares.toTokens(message.rebaseIndex) value, ensuring that the amount emitted matches the actual one transferred by the cross-chain transfer.

Alleviation (47fbf62bbbf2409ff0baf9a18a2945466cb2a576):

The amount emitted within the SendToChain event has been corrected as advised, ensuring that it always corresponds to the actual amount debited from the from address.