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From: Borislav Petkov <bp@alien8.de>
To: Kees Cook <keescook@chromium.org>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Thomas Lendacky <Thomas.Lendacky@amd.com>,
	Mauro Rossi <issor.oruam@gmail.com>, Michael Matz <matz@suse.de>
Subject: Re: [PATCH v3] x86/vmlinux: Fix vmlinux.lds.S with pre-2.23 binutils
Date: Tue, 14 Jan 2020 17:51:35 +0100	[thread overview]
Message-ID: <20200114165135.GK31032@zn.tnic> (raw)
In-Reply-To: <202001131750.C1B8468@keescook>

On Mon, Jan 13, 2020 at 05:53:32PM -0800, Kees Cook wrote:
> NAK: linkers can add things at the end of .text that will go missing from
> the kernel if _etext isn't _outside_ the .text section, truly beyond the
> end of the .text section. This patch will break Control Flow Integrity
> checking since the jump tables are at the end of .text.

Err, which linkers are those? Please elaborate.

In any case, after reading the thread, I can't help but favor the idea
of us bumping min binutils version to 2.23.

Michael (on Cc) says that the 2.21 was kinda broken wrt to the symbols
fun outside of sections, 2.22 tried to fix it, see

  fd952815307f ("x86-32, relocs: Whitelist more symbols for ld bug workaround")

which Arvind pointed out and 2.23 fixed it for real.

Now, 2.23 is still very ancient. I'm looking at our releases: openSUSE
12.1 has the minimum supported gcc version 4.6 by the kernel and
also the minimum binutils version 2.21 which we support according to
Documentation/process/changes.rst

Now, openSUSE 12.1 is ancient and we ourselves advise people to update
to current distros so I don't think anyone would still run it.

So, considering that upping the binutils version would save us from all
this trouble I say we try it after 5.5 releases for a maximum time of a
full 5.6 release cycle and see who complains.

Considering how no one triggered this yet until Arvind, I think no one
would complain. But I might be wrong.

So what do people think? hpa?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  parent reply	other threads:[~2020-01-14 16:51 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 20:23 [PATCH] x86/tools/relocs: Add _etext and __end_of_kernel_reserve to S_REL Arvind Sankar
2020-01-10 20:38 ` Borislav Petkov
2020-01-10 20:50   ` Arvind Sankar
2020-01-10 21:50     ` [PATCH v2] " Arvind Sankar
2020-01-10 21:52       ` Arvind Sankar
2020-01-11 13:02     ` [PATCH] " Borislav Petkov
2020-01-11 17:20       ` Arvind Sankar
2020-01-11 17:32         ` Arvind Sankar
2020-01-13 13:43         ` Borislav Petkov
2020-01-13 16:13           ` Arvind Sankar
2020-01-13 16:38             ` Borislav Petkov
2020-01-13 17:59               ` Arvind Sankar
2020-01-13 18:08                 ` Borislav Petkov
2020-01-14  4:17                   ` Arvind Sankar
2020-01-14 11:25                     ` Borislav Petkov
2020-01-14 16:32                       ` Arvind Sankar
2020-01-14  4:08               ` Arvind Sankar
2020-01-13 19:53             ` [PATCH v3] x86/vmlinux: Fix vmlinux.lds.S with pre-2.23 binutils Arvind Sankar
2020-01-13 21:46               ` Tom Lendacky
2020-01-13 23:06                 ` Arvind Sankar
2020-01-14  1:53               ` Kees Cook
2020-01-14  1:57                 ` H. Peter Anvin
2020-01-14  2:20                   ` Kees Cook
2020-01-14  3:58                   ` Arvind Sankar
2020-01-14  5:05                     ` hpa
2020-01-14 16:51                 ` Borislav Petkov [this message]
2020-01-14 21:50                   ` hpa
2020-01-15  0:21                   ` Arvind Sankar
2020-01-15 12:24                     ` Borislav Petkov
2020-03-16 16:02                       ` [PATCH] Documentation/changes: Raise minimum supported binutils version to 2.23 Borislav Petkov
2020-03-16 20:54                         ` Kees Cook
2020-03-23 20:44                         ` Jason A. Donenfeld
2020-03-23 20:51                           ` Kees Cook
2020-03-23 21:11                             ` Jason A. Donenfeld
2020-03-25 17:33                               ` David Laight
2020-03-24  9:02                             ` Masahiro Yamada
2020-03-24  9:12                               ` Masahiro Yamada
2020-03-24 15:38                                 ` Arvind Sankar
2020-03-24 17:31                                   ` Masahiro Yamada
2020-03-24 21:36                                     ` Arvind Sankar
2020-03-24  9:14                               ` Borislav Petkov
2020-03-24  9:40                                 ` Masahiro Yamada
2020-03-24 12:00                                   ` Borislav Petkov
2020-03-24 16:22                                 ` Jason A. Donenfeld
2020-03-24 16:28                                   ` Borislav Petkov
2020-03-24 16:37                                     ` Linus Torvalds
2020-03-24 16:48                                       ` Borislav Petkov
2020-03-24 21:42                                         ` Arvind Sankar
2020-03-24 22:01                                           ` Arvind Sankar
2020-03-24 22:14                                           ` Linus Torvalds
2020-03-24 23:49                                             ` Arvind Sankar
2020-03-24 17:53                                       ` Kees Cook
2020-03-23 20:50                         ` [PATCH] Documentation/changes: Raise minimum supported binutilsa " Nick Desaulniers
2020-01-13 23:38       ` [PATCH] x86/tools/relocs: Add _etext and __end_of_kernel_reserve to S_REL Arvind Sankar
2020-01-10 20:56   ` Kees Cook
     [not found]     ` <CAEQFVGa4fksPRtiLtBckSgbJY_JSHr07hoy5+5w-pAYym16YVg@mail.gmail.com>
2020-01-11 19:40       ` Fwd: " Mauro Rossi

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