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

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Date:   Mon, 27 Sep 2021 11:26:58 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Alexei Starovoitov <ast@...nel.org>
Cc:     Kees Cook <keescook@...omium.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: [PATCH 0/2] bpf: Build with -Wcast-function-type

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

 include/linux/bpf.h    |  4 +++-
 include/linux/filter.h |  7 +++----
 kernel/bpf/arraymap.c  |  7 +++----
 kernel/bpf/hashtab.c   | 13 ++++++-------
 kernel/bpf/helpers.c   |  5 ++---
 kernel/bpf/verifier.c  | 26 +++++++++-----------------
 6 files changed, 26 insertions(+), 36 deletions(-)

-- 
2.30.2