Fix unsoundness in FromBytes::new_box_slice_zeroed #63
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Previously, `FromBytes::new_box_slice_zeroed` called `Layout::from_size_align_unchecked` with arguments that could overflow `isize`, which would violate its safety preconditions. In this change, we use the safe variant, which returns a `Result` which we can `.expect()`. Though I haven't benchmarked it, this likely has little impact on performance over the optimal code since optimal code would still need to perform the same bounds check that `from_size_align` is performing.
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Breadcrumbs: Looks like the test failure in this PR is related to rust-lang/rust#95295 and rust-lang/rust#101899. |
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Previously, `FromBytes::new_box_slice_zeroed` called `Layout::from_size_align_unchecked` with arguments that could overflow `isize`, which would violate its safety preconditions. In this change, we use the safe variant, which returns a `Result` which we can `.expect()`. Though I haven't benchmarked it, this likely has little impact on performance over the optimal code since optimal code would still need to perform the same bounds check that `from_size_align` is performing.
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Previously,
FromBytes::new_box_slice_zeroedcalledLayout::from_size_align_uncheckedwith arguments that could overflowisize, which would violate its safety preconditions. In this change, we use the safe variant, which returns aResultwhich we can.expect(). Though I haven't benchmarked it, this likely has little impact on performance over the optimal code since optimal code would still need to perform the same bounds check thatfrom_size_alignis performing.