libbpf-cargo: Wrap generated "unsafe" type in MaybeUninit #672
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Certain Rust types that we use in our generated skeleton are not valid for all bit patterns. Bools, for example, are defined to be one byte in size, but their representation allows only for 0 and 1 values to be used in said byte -- everything else is undefined behavior. Enums have similar problems, in that not the entire space of the backing type is necessarily used by variants. The result is an unsoundness issue in our generated skeletons, because C code could accidentally set an enum to an invalid value and Rust code would exhibit undefined behavior. This change fixes this problem by wrapping the corresponding attributes in MaybeUninit. In so doing users have to be explicit when accessing them and make sure that the current representation is indeed valid. Closes: libbpf#589 Signed-off-by: Daniel Müller <[email protected]>
anakryiko
reviewed
Feb 9, 2024
Yeah, will need to fix the tests.
Will do. |
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This pull request should be ready for review now, @anakryiko. |
anakryiko
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Feb 13, 2024
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Certain Rust types that we use in our generated skeleton are not valid for all bit patterns. Bools, for example, are defined to be one byte in size, but their representation allows only for 0 and 1 values to be used in said byte -- everything else is undefined behavior. Enums have similar problems, in that not the entire space of the backing type is necessarily used by variants.
The result is an unsoundness issue in our generated skeletons, because C code could accidentally set an enum to an invalid value and Rust code would exhibit undefined behavior.
This change fixes this problem by wrapping the corresponding attributes in MaybeUninit. In so doing users have to be explicit when accessing them and make sure that the current representation is indeed valid.
Closes: #589