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Message-ID: <839118ce-ff16-a743-d660-dd030a7e2d90@embeddedor.com>
Date:   Wed, 4 Oct 2023 01:38:22 +0200
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Subject: Re: [PATCH] netem: Annotate struct disttable with __counted_by
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To:     Kees Cook <keescook@chromium.org>,
        Stephen Hemminger <stephen@networkplumber.org>
Cc:     Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org, llvm@lists.linux.dev
References: <20231003231823.work.684-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20231003231823.work.684-kees@kernel.org>
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On 10/4/23 01:18, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct disttable.
> 
> Cc: Stephen Hemminger <stephen@networkplumber.org>
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Cong Wang <xiyou.wangcong@gmail.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>   net/sched/sch_netem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
> index 4ad39a4a3cf5..6ba2dc191ed9 100644
> --- a/net/sched/sch_netem.c
> +++ b/net/sched/sch_netem.c
> @@ -67,7 +67,7 @@
>   
>   struct disttable {
>   	u32  size;
> -	s16 table[];
> +	s16 table[] __counted_by(size);
>   };
>   
>   struct netem_sched_data {