0xSmartContract - Vulnerability related to ‘Optimizer Bug Regarding Memory Side Effects of Inline Assembly’

[sherlock-admin]

0xSmartContract

medium

Vulnerability related to ‘Optimizer Bug Regarding Memory Side Effects of Inline Assembly’

Summary

Solidity versions 0.8.13 and 0.8.14 are vulnerable to a recently reported optimizer bug related to inline assembly. Solidity 0.8.15 has been released with a fix.

Vulnerability Detail

AutoRoller.sol inherits solidity contracts from solmate FixedPointMathLib and ERC4626 , and both these uses inline assembly, and optimization is enabled while compiling.

Impact

This bug only occurs under very specific conditions: the legacy optimizer must be enabled rather than the IR pipeline (true for the current project configuration), and the affected assembly blocks must not refer to any local Solidity variables.

Code Snippet

AutoRoller.sol#L5

AutoRoller.sol#L7

FixedPointMathLib.sol#L36-L51

contracts/src/AutoRoller.sol:

  4: import { ERC20 } from "solmate/tokens/ERC20.sol";
  5: import { FixedPointMathLib } from "solmate/utils/FixedPointMathLib.sol";
  6: import { SafeTransferLib } from "solmate/utils/SafeTransferLib.sol";
  7: import { ERC4626 } from "solmate/mixins/ERC4626.sol";

contracts/foundry.toml:
  1: [profile.default]
  8: optimizer_runs = 10000

Tool used

Manual Review

Recommendation

Use recent Solidity version 0.8.15 which has the fix for these issues.

[jparklev]

We will bump our solidity patch version

[jparklev]

Fix: https://github.com/sense-finance/auto-roller/pull/18

[aktech297]

Verified the fix. The contracts are updated with 0.8.15 compiler version.