OZ L02; Spearbit 87; improved calldata checks #316
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hensha256
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hensha256
changed the title
| assembly ("memory-safe") { | ||
| res.length := length | ||
| res.offset := offset | ||
| let bytesOffset := and(_bytes.offset, OFFSET_OR_LENGTH_MASK) |
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Masking done here but not in toBytes--intentional?
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have pushed an update for that 2fd239f
src/libraries/CalldataDecoder.sol
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| returns (uint256 length, uint256 offset) | ||
| { | ||
| function toBytes(bytes calldata _bytes, uint256 _arg) internal pure returns (bytes calldata res) { | ||
| uint256 length; | ||
| uint256 relativeOffset; | ||
| assembly ("memory-safe") { | ||
| // The offset of the `_arg`-th element is `32 * arg`, which stores the offset of the length pointer. | ||
| // shl(5, x) is equivalent to mul(32, x) | ||
| let lengthPtr := add(_bytes.offset, calldataload(add(_bytes.offset, shl(5, _arg)))) |
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if you give a very high offset value for the bytes here, you could overflow this value; could apply the mask to the value, or check that it matches some fixed value (especially if it's a sole argument in which case it'd always be 0x20)
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i think youre commenting on an old version - i apply the mask now. Added in 2fd239f
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oh do you mean mask arg? i'm not too concerned about that as we will always pass in that in internally to the code
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yeah i think this comment is outdated now!
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| bytes memory invalidParams = new bytes(params.length - 1); | ||
| // dont copy the final byte | ||
| for (uint256 i = 0; i < params.length - 2; i++) { |
| } | ||
| if (_bytes.length < length + relativeOffset) revert SliceOutOfBounds(); | ||
| } | ||
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| /// @notice Decode the `_arg`-th element in `_bytes` as `bytes` | ||
| /// @param _bytes The input bytes string to extract a bytes string from | ||
| /// @param _bytes The input bytes string to extract a bytes array from | ||
| /// @param _arg The index of the argument to extract |
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can you add a comment for when this is expected to revert with the SliceOutOfBounds error?
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I think |
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