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From: Sasha Levin <sasha.levin@oracle.com>
To: Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>
Cc: "security@kernel.org" <security@kernel.org>,
	X86 ML <x86@kernel.org>, Borislav Petkov <bp@alien8.de>,
	linux-kernel@vger.kernel.org,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v2 2/3] x86/ldt: Make modify_ldt optional
Date: Tue, 21 Jul 2015 16:20:44 -0400	[thread overview]
Message-ID: <55AEA99C.3030608@oracle.com> (raw)
In-Reply-To: <06f4a63325ac221868770a8d63207d74b160df89.1437508486.git.luto@kernel.org>

On 07/21/2015 03:59 PM, Andy Lutomirski wrote:
> The modify_ldt syscall exposes a large attack surface and is
> unnecessary for modern userspace.  Make it optional.

Since this a "default y" option I think we need to make the
implications of this a bit clearer.

Do we know what userspace would break?

Maybe add a WARN_ONCE() in a stub syscall?


Thanks,
Sasha

  reply	other threads:[~2015-07-21 20:21 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-21 19:59 [PATCH v2 0/3] x86: modify_ldt improvement, test, and config option Andy Lutomirski
2015-07-21 19:59 ` [PATCH v2 1/3] x86/ldt: Make modify_ldt synchronous Andy Lutomirski
2015-07-21 21:53   ` Boris Ostrovsky
2015-07-21 23:38     ` Andrew Cooper
2015-07-22  0:07       ` Andy Lutomirski
2015-07-22  0:21         ` Andrew Cooper
2015-07-22  0:28           ` Andy Lutomirski
2015-07-22  0:49             ` Andrew Cooper
2015-07-22  1:06               ` Andy Lutomirski
2015-07-22  2:04               ` [Xen-devel] " Boris Ostrovsky
2015-07-22  2:13                 ` Andy Lutomirski
2015-07-22  2:01   ` Brian Gerst
2015-07-22  2:12     ` Andy Lutomirski
2015-07-22  2:53       ` Brian Gerst
2015-07-22  4:22         ` Andy Lutomirski
2015-07-21 19:59 ` [PATCH v2 2/3] x86/ldt: Make modify_ldt optional Andy Lutomirski
2015-07-21 20:20   ` Sasha Levin [this message]
2015-07-21 20:27     ` Andy Lutomirski
2015-07-21 20:28   ` Brian Gerst
2015-07-21 20:34     ` Andy Lutomirski
2015-07-21 20:54       ` Brian Gerst
2015-07-22  6:06       ` Ingo Molnar
2015-07-22  6:23         ` Andy Lutomirski
2015-07-22  6:27           ` Ingo Molnar
2015-07-22 18:49             ` Andy Lutomirski
2015-07-22 12:34           ` Willy Tarreau
2015-07-21 19:59 ` [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt Andy Lutomirski
2015-07-21 22:02   ` Boris Ostrovsky
2015-07-21 22:34     ` Andy Lutomirski
2015-07-21 23:36   ` Willy Tarreau
2015-07-21 23:40     ` Andy Lutomirski

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