c4-bot-8 commented 2 months ago

Lines of code

Vulnerability details

C4 issue

None

Comments

Previously, the admin of the Neuron contract could setup airdrops by approving NRN amounts to users using Neuron::setupAirdrop. This was potentially problematic, because airdropping lots of addresses would be a gas intensive operation for the admin account.

Mitigation

PR #16 Setting up airdrops has been modified to use merkle trees. Instead of directly approving addresses to claim NRN from the treasury, the admin now sets a merkle root calling Neuron::setMerkleRoot and then users can use a merkle proof to Neuron::claim the airdropped amount. This new mechanism slightly increases the gas cost for claiming while significantly reduces the gas cost of setting the airdrop.

The state variable rootClaimedAirdrop correctly keeps track of claims and it's possible to setup several airdrops.

Suggestion

In Neuron::claim, use _transfer() directly instead of using _approve() + transferFrom(). The latter increases the allowance and then removes it, which is equivalent to simply _transfer() the tokens.

Conclusion

LGTM

c4-judge commented 2 months ago

jhsagd76 marked the issue as satisfactory