stake.link

Summary

Casting down a uint256 to uint64 can cause an overflow error which would make it so the startTime of the created Lock would be entirely wrong

Vulnerability Details

The SDLPool.sol::_createLock function cast a type of uint256 (block.timestamp) to a type of uint64, this type of down casting can cause an overflow error. The overflow error can occur in a scenario where the original value of the uint256 (block.timestamp) is greater than the maximum value that a uint64 can hold (18,446,744,073,709,551,615). In a scenario where such overflow happens then the startTime of the Lock created would be entirely wrong. This vulnerability would happen by Sun Jul 21 2554 23:34:33 GMT+0000

Impact

Casting down a uint256 to uint64 in SDLPool.sol::_createLock function to get the startTime on a Lock would make it so the startTime on that Lock is actually wrong in a scenario where the value of the original uint256 we are casting down to uint64 is actually larger than the maximum value that a uint64 can hold

Tools Used

Manual Review

Recommendations

The startTime field on the Lock struct should be changed to a type of uint256 so that there won't be any need to cast down the type of uint256 that would be returned when we call block.timestamp