Messages in this thread | | | From | Christian Brauner <> | Subject | [PATCH 0/3] bpf: switch to new usercopy helpers | Date | Wed, 9 Oct 2019 18:09:04 +0200 |
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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.
Thanks! Christian
/* Reference */ [1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
Christian Brauner (3): bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() bpf: use copy_struct_from_user() in bpf() syscall
kernel/bpf/syscall.c | 38 ++++++++++++-------------------------- 1 file changed, 12 insertions(+), 26 deletions(-)
-- 2.23.0
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