Re: [PATCH v2 bpf-next 0/2] enforce W^X for trampoline and dispatcher

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2022-09-26 at 11:47 -0700, Song Liu wrote:
> Changes v1 => v2:
> 1. Update arch_prepare_bpf_dispatcher to use a RO image and a RW buffer.
>    (Alexei) Note: I haven't found an existing test to cover this part, so
>    this part was tested manually (comparing the generated dispatcher is
>    the same).
> 
> Jeff Layton reported CPA W^X warning linux-next [1]. It turns out to be
> W^X issue with bpf trampoline and bpf dispatcher. Fix these by:
> 
> 1. Use bpf_prog_pack for bpf_dispatcher;
> 2. Set memory permission properly with bpf trampoline.
> 
> [1] https://lore.kernel.org/lkml/c84cc27c1a5031a003039748c3c099732a718aec.camel@kernel.org/
> 
> Song Liu (2):
>   bpf: use bpf_prog_pack for bpf_dispatcher
>   bpf: Enforce W^X for bpf trampoline
> 
>  arch/x86/net/bpf_jit_comp.c | 16 ++++++++--------
>  include/linux/bpf.h         |  4 ++--
>  include/linux/filter.h      |  5 +++++
>  kernel/bpf/core.c           |  9 +++++++--
>  kernel/bpf/dispatcher.c     | 27 +++++++++++++++++++++------
>  kernel/bpf/trampoline.c     | 22 +++++-----------------
>  6 files changed, 48 insertions(+), 35 deletions(-)
> 
> --
> 2.30.2

Your patch seems to have fixed the issue. You can add:

Tested-by: Jeff Layton <jlayton@kernel.org>

Thanks!