RAB Pragma of CappedMath Updated #317
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Updating to the latest commit as of 5th May 2020
clesaege
requested changes
May 5, 2020
contracts/libraries/CappedMath.sol
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| */ | ||
| function subCap(uint _a, uint _b) internal pure returns (uint) { | ||
| if (_b > _a) | ||
| if (_b >= _a) |
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">" was OK as if they are equal l34 will return 0.
_a==_b is not an edge case so better treated normally. And "a>=b" is more gas intensive than "a>b" as from a compiler perspective it expends to "a>b || a==b".
contracts/libraries/CappedMath.sol
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| // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522 | ||
| if (_a == 0) | ||
| uint c = _a * _b; | ||
| if (c == 0) |
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This code change creates a critical vulnerability, we can have "c==0" while "a!=0" and "b!=0" when there is an overflow (ex: a=2^255 and b=2). In this case your code would return 0 while the correct return would be UINT_MAX.
remedcu
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