Re: [PATCH 0/2] bpf: Build with -Wcast-function-type

[Alexei Starovoitov]

On Mon, Sep 27, 2021 at 10:24 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Mon, Sep 27, 2021 at 11:27 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > In order to keep ahead of cases in the kernel where Control Flow Integrity
> > (CFI) may trip over function call casts, enabling -Wcast-function-type
> > is helpful. To that end, replace BPF_CAST_CALL() as it triggers warnings
> > with this option and is now one of the last places in the kernel in need
> > of fixing.
> >
> > Thanks,
> >
> > -Kees
> >
> > Kees Cook (2):
> >   bpf: Replace "want address" users of BPF_CAST_CALL with BPF_CALL_IMM
> >   bpf: Replace callers of BPF_CAST_CALL with proper function typedef
> >
>
> Both patches look good to me. For the series:
>
> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>

It needs a rebase to bpf-next:
In file included from ../lib/test_bpf.c:12:
../lib/test_bpf.c: In function ‘prepare_tail_call_tests’:
../lib/test_bpf.c:12442:27: error: implicit declaration of function
‘BPF_CAST_CALL’; did you mean ‘BPF_EMIT_CALL’?
[-Werror=implicit-function-declaration]
     *insn = BPF_EMIT_CALL(BPF_CAST_CALL(addr));

Please mark the patches as [PATCH bpf-next v2] to help CI pick the right tree.