Open code423n4 opened 2 years ago
ye0lde
Caching state variables or using existing local variables instead of repeatedly reading state variables will save gas by converting SLOADs to MLOADs.
feeRecipient_ can be used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L55 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L75
swapFee_ can be used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L57 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L66
A cached version of feeRecipient can be declared at 246 and used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L247 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L253 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L254 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L257 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L258
Visual Studio Code, Remix
See Proof of Concept
Handle
ye0lde
Vulnerability details
Impact
Caching state variables or using existing local variables instead of repeatedly reading state variables will save gas by converting SLOADs to MLOADs.
Proof of Concept
feeRecipient_ can be used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L55 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L75
swapFee_ can be used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L57 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L66
A cached version of feeRecipient can be declared at 246 and used here: https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L247 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L253 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L254 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L257 https://github.com/code-423n4/2021-10-tally/blob/c585c214edb58486e0564cb53d87e4831959c08b/contracts/swap/Swap.sol#L258
Tools Used
Visual Studio Code, Remix
Recommended Mitigation Steps
See Proof of Concept