linux-kernel - Re: [PATCH 5.10 002/545] x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments

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Date:   Fri, 19 Aug 2022 10:13:36 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Fangrui Song <maskray@...gle.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH 5.10 002/545] x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments

Sorry for not reporting this sooner; been out sick all week with COVID.

On Fri, Aug 19, 2022 at 8:46 AM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
>
> From: Nick Desaulniers <ndesaulniers@...gle.com>
>
> commit ffcf9c5700e49c0aee42dcba9a12ba21338e8136 upstream.
>

<snip>

> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -68,6 +68,10 @@ LDFLAGS_vmlinux := -pie $(call ld-option
>  ifdef CONFIG_LD_ORPHAN_WARN
>  LDFLAGS_vmlinux += --orphan-handling=warn
>  endif
> +LDFLAGS_vmlinux += -z noexecstack
> +ifeq ($(CONFIG_LD_IS_BFD),y)

5.10.y is missing CONFIG_LD_IS_BFD. Specifically

commit 02aff8592204 ("kbuild: check the minimum linker version in Kconfig")
which first landed in v5.12-rc1.  I'd recommend simply dropping the
`ifeq` guards; the ld-option guard will still work.  Otherwise GNU BFD
2.39 users will observe linker warnings related to rwx-segments.

Greg, do you mind dropping this patch and I'll supply a v2, or is it
too late and I should send a patch on top?

> +LDFLAGS_vmlinux += $(call ld-option,--no-warn-rwx-segments)
> +endif
>  LDFLAGS_vmlinux += -T
>
>  hostprogs      := mkpiggy

-- 
Thanks,
~Nick Desaulniers