From: Rich Felker <dalias@libc.org>
To: Kees Cook <keescook@chromium.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>,
linux-sh@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>,
Paul Mundt <lethal@linux-sh.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] sh: machvec: Use char[] for section boundaries
Date: Thu, 8 Sep 2022 18:15:39 -0400 [thread overview]
Message-ID: <20220908221538.GD8773@brightrain.aerifal.cx> (raw)
In-Reply-To: <20220907234345.96798-1-keescook@chromium.org>
On Wed, Sep 07, 2022 at 04:43:45PM -0700, Kees Cook wrote:
> As done for other sections, define the extern as a character array,
> which relaxes many of the compiler-time object size checks, which would
> otherwise assume it's a single long. Solves the following build error:
>
> arch/sh/kernel/machvec.c: error: array subscript 'struct sh_machine_vector[0]' is partly outside array bounds of 'long int[1]' [-Werror=array-bounds]: => 105:33
LGMT. This is the approach I recommend for this general type of
mechanism. So,
Acked-by: Rich Felker <dalias@libc.org>
Since I haven't been on top of collating patches for upstreaming, I'd
be happy if anyone else wants to take this in their tree before I get
back to it.
Rich
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: linux-sh@vger.kernel.org
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Link: https://lore.kernel.org/lkml/alpine.DEB.2.22.394.2209050944290.964530@ramsan.of.borg/
> Fixes: 9655ad03af2d ("sh: Fixup machvec support.")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> arch/sh/include/asm/sections.h | 2 +-
> arch/sh/kernel/machvec.c | 10 +++++-----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/sh/include/asm/sections.h b/arch/sh/include/asm/sections.h
> index 8edb824049b9..0cb0ca149ac3 100644
> --- a/arch/sh/include/asm/sections.h
> +++ b/arch/sh/include/asm/sections.h
> @@ -4,7 +4,7 @@
>
> #include <asm-generic/sections.h>
>
> -extern long __machvec_start, __machvec_end;
> +extern char __machvec_start[], __machvec_end[];
> extern char __uncached_start, __uncached_end;
> extern char __start_eh_frame[], __stop_eh_frame[];
>
> diff --git a/arch/sh/kernel/machvec.c b/arch/sh/kernel/machvec.c
> index d606679a211e..57efaf5b82ae 100644
> --- a/arch/sh/kernel/machvec.c
> +++ b/arch/sh/kernel/machvec.c
> @@ -20,8 +20,8 @@
> #define MV_NAME_SIZE 32
>
> #define for_each_mv(mv) \
> - for ((mv) = (struct sh_machine_vector *)&__machvec_start; \
> - (mv) && (unsigned long)(mv) < (unsigned long)&__machvec_end; \
> + for ((mv) = (struct sh_machine_vector *)__machvec_start; \
> + (mv) && (unsigned long)(mv) < (unsigned long)__machvec_end; \
> (mv)++)
>
> static struct sh_machine_vector * __init get_mv_byname(const char *name)
> @@ -87,8 +87,8 @@ void __init sh_mv_setup(void)
> if (!machvec_selected) {
> unsigned long machvec_size;
>
> - machvec_size = ((unsigned long)&__machvec_end -
> - (unsigned long)&__machvec_start);
> + machvec_size = ((unsigned long)__machvec_end -
> + (unsigned long)__machvec_start);
>
> /*
> * Sanity check for machvec section alignment. Ensure
> @@ -102,7 +102,7 @@ void __init sh_mv_setup(void)
> * vector (usually the only one) from .machvec.init.
> */
> if (machvec_size >= sizeof(struct sh_machine_vector))
> - sh_mv = *(struct sh_machine_vector *)&__machvec_start;
> + sh_mv = *(struct sh_machine_vector *)__machvec_start;
> }
>
> pr_notice("Booting machvec: %s\n", get_system_type());
> --
> 2.34.1
next prev parent reply other threads:[~2022-09-08 22:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 23:43 [PATCH] sh: machvec: Use char[] for section boundaries Kees Cook
2022-09-08 6:53 ` Geert Uytterhoeven
2022-09-08 12:17 ` Gustavo A. R. Silva
2022-09-08 22:15 ` Rich Felker [this message]
2022-09-13 17:34 ` Kees Cook
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