fix(contracts): check transfer return value on profit sweep#307
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fix(contracts): check transfer return value on profit sweep#307
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The profit sweep at executeOperation line 413 discarded the return value of IERC20(p.debtToken).transfer(COLD_WALLET, profit). Standard ERC-20s revert on failure, but BEP-20 and legacy tokens return `false` without reverting. A silent `false` would leave the profit stranded in this contract while the subsequent emit, Aave approval, and flashloan repayment all succeed — operator logs would show a successful liquidation while the cold wallet received nothing. Adopt the same bool-ok + require pattern already used by rescue() at :463 (no SafeERC20, consistent with the no-external-dependency policy). Other approve() call sites in this file also discard return values (lines 331, 344, 373, 390, 428) — tracked as a follow-up, out of scope here.
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Summary
mev-sim-auditorflaggedCharonLiquidator.sol:413as a P3 issue during static audit of PR #305:IERC20(p.debtToken).transfer(COLD_WALLET, profit)discarded the return value. Standard ERC-20s revert on failure, but BEP-20 and some legacy tokens returnfalsewithout reverting. A silentfalsewould strand profit in this contract while the emit, Aave approval, and flashloan repayment all succeed — operator logs would show a successful liquidation while the cold wallet received nothing.Fix
Adopt the same
bool ok; require(ok, ...)pattern already used byrescue()at:463. NoSafeERC20— consistent with the no-external-dependency policy stated at:440.Review (solidity-secure-dev): APPROVE
SafeERC20would violate no-deps policy.debtToken:executeOperationrejects re-entry atrequire(msg.sender == AAVE_POOL)andexecuteLiquidationisnonReentrant.LiquidationExecutedemit is AFTER therequire, so a failed sweep never emits a misleading success log.Follow-up (out of scope)
Five
approve()calls in the same file also discard their return values (lines 331, 344, 373, 390, 428). Tracked for a separate hardening PR; Venus-listed BSC tokens all conform today but the pattern carries the same theoretical gap.Test plan
forge build --force-> Compiler run successfulfalseon transfer causes executeOperation to revert with"profit: transfer failed". Runs on feat/25 (parallel-terminal scope) after this merges.