linux-kernel - Re: [PATCH v6 4/4] x86/ldt: Make modify

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]

Date:	Fri, 31 Jul 2015 15:49:21 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Andy Lutomirski <luto@...nel.org>
Cc:	X86 ML <x86@...nel.org>, Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	"security@...nel.org" <security@...nel.org>,
	Sasha Levin <sasha.levin@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Jan Beulich <jbeulich@...e.com>,
	xen-devel <xen-devel@...ts.xen.org>
Subject: Re: [PATCH v6 4/4] x86/ldt: Make modify_ldt optional


* Andy Lutomirski <luto@...nel.org> wrote:

> The modify_ldt syscall exposes a large attack surface and is
> unnecessary for modern userspace.  Make it optional.
> 
> Reviewed-by: Kees Cook <keescook@...omium.org>
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
> ---
>  arch/x86/Kconfig                   | 17 +++++++++++++++++
>  arch/x86/include/asm/mmu.h         |  2 ++
>  arch/x86/include/asm/mmu_context.h | 28 +++++++++++++++++++++-------
>  arch/x86/kernel/Makefile           |  3 ++-
>  arch/x86/kernel/cpu/perf_event.c   |  4 ++++
>  arch/x86/kernel/process_64.c       |  2 ++
>  arch/x86/kernel/step.c             |  2 ++
>  kernel/sys_ni.c                    |  1 +
>  8 files changed, 51 insertions(+), 8 deletions(-)

btw., I fixed a (rare) build failure on MATH_EMULATION=y && !MODIFY_LDT_SYSCALL:

  arch/x86/math-emu/fpu_system.h:21:71: error: ‘mm_context_t’ has no member named ‘ldt’

I took the easy fix: made MATH_EMULATION depend on MODIFY_LDT_SYSCALL for now.

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/