bpf: don't mark FP reg as uninit
authorAlexei Starovoitov <ast@fb.com>
Fri, 1 Dec 2017 05:31:37 +0000 (21:31 -0800)
committerDaniel Borkmann <daniel@iogearbox.net>
Fri, 1 Dec 2017 10:25:10 +0000 (11:25 +0100)
commit19ceb4178d31e543479d75e20c2f9df08f16632f
treebef3d86b652404095dff4416aa072332e774e9db
parent4e92024a48ecbd06fba3ccfb2174abd3d2f54a83
bpf: don't mark FP reg as uninit

when verifier hits an internal bug don't mark register R10==FP as uninit,
since it's read only register and it's not technically correct to let
verifier run further, since it may assume that R10 has valid auxiliary state.

While developing subsequent patches this issue was discovered,
though the code eventually changed that aux reg state doesn't have
pointers any more it is still safer to avoid clearing readonly register.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
kernel/bpf/verifier.c