linux-kernel - Re: [PATCH v3 0/2] x86/boot: fix relying on link order

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Y7xNoPT9aC/nIbnM@gmail.com>
Date:   Mon, 9 Jan 2023 18:23:44 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Alexander Lobakin <alexandr.lobakin@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Jiri Slaby <jirislaby@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Tony Luck <tony.luck@...el.com>,
        Kees Cook <keescook@...omium.org>,
        Masahiro Yamada <masahiroy@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/2] x86/boot: fix relying on link order


* Alexander Lobakin <alexandr.lobakin@...el.com> wrote:

> Currently, the x86 decompressor code expects the kernel entry point to be
> exactly at the beginning of the kernel image. It's always been true, but
> is hacky in multiple ways: special .head.text section and linking certain
> object files first to have them at the beginning.
> Make the code independent from the link order and then kill the latter.
> The former is to be resolved a bit later.
> 
> I didn't put any "Fixes:" tag since it's not linear. The lines changed
> with 0001 came from the initial x86 KASLR series, but that unconditional
> jump to the kernel beginning already was there. It goes at least from the
> set that brought relocatable kernel support to x86, but this is quite
> prehistoric already and might not look really relatable.
> 
> Alexander Lobakin (2):
>   x86/boot: robustify calling startup_{32,64}() from the decompressor
>     code
>   scripts/head-object-list: remove x86 from the list
> 
>  arch/x86/boot/compressed/head_32.S |  2 +-
>  arch/x86/boot/compressed/head_64.S |  2 +-
>  arch/x86/boot/compressed/misc.c    | 18 +++++++++++-------
>  scripts/head-object-list.txt       |  6 ------
>  4 files changed, 13 insertions(+), 15 deletions(-)

That's a really nice fix/robustification improvement - I've applied your 
series to tip:x86/boot and will push it out after some testing.

Thanks,

	Ingo