Hello, Thanks for the feedbacks. Here is the v2 that splits the patch into two commits. I hope I made it correctly.
/Jérémy --- Helper callbacks enter BPF subprograms through bpf_callback_t, whose runtime ABI supplies five arguments. BTF validation nevertheless permits static callback subprograms to declare more than five arguments when JIT stack arguments are supported. This lets verifier state for a callback use outgoing stack argument slots prepared at the helper call site. The helper does not pass those slots. On x86-64, callback loads of arguments seven and later therefore read the helper native frame instead of the synthetic values checked by the verifier. This series rejects callback subprograms with incoming stack arguments and adds verifier coverage for the rejection. Changes v1 -> v2: - split the verifier fix and selftest into separate patches; - drop the callback-specific verifier log message and stop matching it in the selftest; - use __clobber_common plus r6 in the selftest. Jérémy Jean (2): bpf: reject stack-argument callback subprograms selftests/bpf: add callback stack-argument rejection test v1: https://lore.kernel.org/bpf/[email protected]/T/ kernel/bpf/verifier.c | 2 ++ .../selftests/bpf/progs/verifier_stack_arg.c | 32 +++++++++++++++++++ 2 files changed, 34 insertions(+) -- 2.47.3
