On Wed, Oct 9, 2019 at 9:09 AM Christian Brauner <christian.brau...@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).
