Does only function involving ETH transactions need reentrancy guard?

Question

I thought so as it may induces fallback() functions, however, I saw in Synthetix's staking contracts, they use reentrancy guard on so many functions that does not involve ETH at all?

https://github.com/Synthetixio/synthetix/blob/develop/contracts/StakingRewards.sol

please clarify which function because i don't see any abnormal. — haxerl, May 31 '22 at 04:31
no it has nothing to do with "only involving Eth transactions" — Majd TL, May 31 '22 at 06:32
Also see https://ethereum.stackexchange.com/questions/8551/ethereum-smart-contract-security-checklist/8593#8593 — Mikko Ohtamaa, May 31 '22 at 19:08

score 0 · Answer 1 · answered May 31 '22 at 14:29

Any contract that makes external function calls should at least be considered for reentrancy protection, because the external contract could be abused in a malicious way.

For example, if you are working with ERC777 tokens, you have to pay careful attention to your code to protect against reentrancy through the tokensReceived() hook. This was the cause of the $11.7M Agave/Hundred Finance hack.

Does only function involving ETH transactions need reentrancy guard?

1 Answers1