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    SubjectRe: [PATCH 0/3] bpf: switch to new usercopy helpers
    On Wed, Oct 9, 2019 at 9:09 AM Christian Brauner
    <christian.brauner@ubuntu.com> wrote:
    >
    > Hey everyone,
    >
    > In v5.4-rc2 we added two new helpers check_zeroed_user() and
    > copy_struct_from_user() including selftests (cf. [1]). It is a generic
    > interface designed to copy a struct from userspace. The helpers will be
    > especially useful for structs versioned by size of which we have quite a
    > few.
    >
    > The most obvious benefit is that this helper lets us get rid of
    > duplicate code. We've already switched over sched_setattr(), perf_event_open(),
    > and clone3(). More importantly it will also help to ensure that users
    > implementing versioning-by-size end up with the same core semantics.
    >
    > This point is especially crucial since we have at least one case where
    > versioning-by-size is used but with slighly different semantics:
    > sched_setattr(), perf_event_open(), and clone3() all do do similar
    > checks to copy_struct_from_user() while rt_sigprocmask(2) always rejects
    > differently-sized struct arguments.
    >
    > This little series switches over bpf codepaths that have hand-rolled
    > implementations of these helpers.

    check_zeroed_user() is not in bpf-next.
    we will let this set sit in patchworks for some time until bpf-next
    is merged back into net-next and we fast forward it.
    Then we can apply it (assuming no conflicts).

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