Commit dae5466c authored by Benno Lossin's avatar Benno Lossin
Browse files

rust: pin-init: add `?Sized` bounds to traits in `#[pin_data]` macro 



The `#[pin_data]` macro uses some auxiliary traits to ensure that a user
does not implement `Drop` for the annotated struct, as that is unsound
and can lead to UB. However, if the struct that is annotated is
`!Sized`, the current bounds do not work, because `Sized` is an implicit
bound for generics.

This is *not* a soundness hole of pin-init, as it currently is
impossible to construct an unsized struct using pin-init.

Tested-by: default avatarAndreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: default avatarGary Guo <gary@garyguo.net>
Signed-off-by: default avatarBenno Lossin <lossin@kernel.org>
parent 560f6d13

rust/pin-init/internal/src/pin_data.rs

+2 −2
Original line number Diff line number Diff line
@@ -215,7 +215,7 @@ fn drop(&mut self) { 
            // if it also implements `Drop`

            trait MustNotImplDrop {}

            #[expect(drop_bounds)]

            impl<T: ::core::ops::Drop> MustNotImplDrop for T {}

            impl<T: ::core::ops::Drop + ?::core::marker::Sized> MustNotImplDrop for T {}

            impl #impl_generics MustNotImplDrop for #ident #ty_generics

                #whr

            {}
@@ -224,7 +224,7 @@ impl #impl_generics MustNotImplDrop for #ident #ty_generics 
            // `PinnedDrop` as the parameter to `#[pin_data]`.

            #[expect(non_camel_case_types)]

            trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}

            impl<T: ::pin_init::PinnedDrop>

            impl<T: ::pin_init::PinnedDrop + ?::core::marker::Sized>

                UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}

            impl #impl_generics

                UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for #ident #ty_generics