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From: Ingo Molnar <mingo@kernel.org>
To: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Brian Gerst <brgerst@gmail.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	stable <stable@vger.kernel.org>
Subject: Re: [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels
Date: Mon, 14 Apr 2014 09:27:56 +0200	[thread overview]
Message-ID: <20140414072755.GA719@gmail.com> (raw)
In-Reply-To: <53483896.9070404@linux.intel.com>


* H. Peter Anvin <hpa@linux.intel.com> wrote:

> On 04/11/2014 11:41 AM, Linus Torvalds wrote:
> > 
> > Ok, so you actually do this on x86-64, and it currently works? For
> > some reason I thought that 16-bit windows apps already didn't work.
> > 
> 
> Some will work, because not all 16-bit software care about the upper
> half of ESP getting randomly corrupted.
> 
> That is the "functionality bit" of the problem.  The other bit, of
> course, is that that random corruption is the address of the kernel stack.
> 
> > Because if we have working users of this, then I don't think we can do
> > the "we don't support 16-bit segments", or at least we need to make it
> > runtime configurable.
> 
> I'll let you pick what the policy should be here.  I personally 
> think that we have to be able to draw a line somewhere sometimes 
> (Microsoft themselves haven't supported running 16-bit binaries for 
> several Windows generations now), but it is your policy, not mine.

I think the mmap_min_addr model works pretty well:

 - it defaults to secure

 - allow a security policy to grant an exception to a known package, 
   built by the distro

 - end user can also grant an exception

This essentially punts any 'makes the system less secure' exceptions 
to the distro and the end user.

Thanks,

	Ingo

  reply	other threads:[~2014-04-14  7:28 UTC|newest]

Thread overview: 137+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-11 17:36 [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels tip-bot for H. Peter Anvin
2014-04-11 18:12 ` Andy Lutomirski
2014-04-11 18:20   ` H. Peter Anvin
2014-04-11 18:27 ` Brian Gerst
2014-04-11 18:29   ` H. Peter Anvin
2014-04-11 18:35     ` Brian Gerst
2014-04-11 21:16     ` Andy Lutomirski
2014-04-11 21:24       ` H. Peter Anvin
2014-04-11 21:53         ` Andy Lutomirski
2014-04-11 21:59           ` H. Peter Anvin
2014-04-11 22:15             ` Andy Lutomirski
2014-04-11 22:18               ` H. Peter Anvin
2014-04-13  4:20           ` H. Peter Anvin
2014-04-12 23:26         ` Alexander van Heukelum
2014-04-12 23:31           ` H. Peter Anvin
2014-04-12 23:49             ` Alexander van Heukelum
2014-04-13  0:03               ` H. Peter Anvin
2014-04-13  1:25                 ` Andy Lutomirski
2014-04-13  1:29                   ` Andy Lutomirski
2014-04-13  3:00                     ` H. Peter Anvin
2014-04-11 21:34       ` Linus Torvalds
2014-04-11 18:41   ` Linus Torvalds
2014-04-11 18:45     ` Brian Gerst
2014-04-11 18:50       ` Linus Torvalds
2014-04-12  4:44         ` Brian Gerst
2014-04-12 17:18           ` H. Peter Anvin
2014-04-12 19:35             ` Borislav Petkov
2014-04-12 19:44               ` H. Peter Anvin
2014-04-12 20:11                 ` Borislav Petkov
2014-04-12 20:34                   ` Brian Gerst
2014-04-12 20:59                     ` Borislav Petkov
2014-04-12 21:13                       ` Brian Gerst
2014-04-12 21:40                         ` Borislav Petkov
2014-04-14  7:21                           ` Ingo Molnar
2014-04-14  9:44                             ` Borislav Petkov
2014-04-14  9:47                               ` Ingo Molnar
2014-04-12 21:53                 ` Linus Torvalds
2014-04-12 22:25                   ` H. Peter Anvin
2014-04-13  2:56                     ` Andi Kleen
2014-04-13  3:02                       ` H. Peter Anvin
2014-04-13  3:13                       ` Linus Torvalds
2014-04-12 20:29             ` Brian Gerst
2014-04-14  7:48         ` Alexandre Julliard
2014-05-07  9:18           ` Sven Joachim
2014-05-07 10:18             ` Borislav Petkov
2014-05-07 16:57             ` Linus Torvalds
2014-05-07 17:09               ` H. Peter Anvin
2014-05-07 17:50                 ` Alexandre Julliard
2014-05-08  6:43                 ` Sven Joachim
2014-05-08 13:50                   ` H. Peter Anvin
2014-05-08 20:13                     ` H. Peter Anvin
2014-05-08 20:40                     ` H. Peter Anvin
2014-05-12 13:16               ` Josh Boyer
2014-05-12 16:52                 ` H. Peter Anvin
2014-05-14 23:43               ` [tip:x86/urgent] x86-64, modify_ldt: Make support for 16-bit segments a runtime option tip-bot for Linus Torvalds
2014-04-11 18:46     ` [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels H. Peter Anvin
2014-04-14  7:27       ` Ingo Molnar [this message]
2014-04-14 15:45         ` H. Peter Anvin
2014-04-13  2:54     ` Andi Kleen
2014-04-21 22:47 ` [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE* H. Peter Anvin
2014-04-21 23:19   ` Andrew Lutomirski
2014-04-21 23:29     ` H. Peter Anvin
2014-04-22  0:37       ` Andrew Lutomirski
2014-04-22  0:53         ` H. Peter Anvin
2014-04-22  1:06           ` Andrew Lutomirski
2014-04-22  1:14             ` H. Peter Anvin
2014-04-22  1:28               ` Andrew Lutomirski
2014-04-22  1:47                 ` H. Peter Anvin
2014-04-22  1:53                   ` Andrew Lutomirski
2014-04-22 11:23                     ` Borislav Petkov
2014-04-22 14:46                       ` Borislav Petkov
2014-04-22 16:03                         ` Andrew Lutomirski
2014-04-22 16:10                           ` H. Peter Anvin
2014-04-22 16:33                             ` Andrew Lutomirski
2014-04-22 16:43                               ` Linus Torvalds
2014-04-22 17:00                                 ` Andrew Lutomirski
2014-04-22 17:04                                   ` Linus Torvalds
2014-04-22 17:11                                     ` Andrew Lutomirski
2014-04-22 17:15                                       ` H. Peter Anvin
2014-04-23  9:54                                         ` One Thousand Gnomes
2014-04-23 15:53                                           ` H. Peter Anvin
2014-04-23 17:08                                             ` Andrew Lutomirski
2014-04-23 17:16                                               ` H. Peter Anvin
2014-04-23 17:25                                                 ` Andrew Lutomirski
2014-04-23 17:28                                                   ` H. Peter Anvin
2014-04-23 17:45                                                     ` Andrew Lutomirski
2014-04-22 17:19                                       ` Linus Torvalds
2014-04-22 17:29                                         ` H. Peter Anvin
2014-04-22 17:46                                           ` Andrew Lutomirski
2014-04-22 17:59                                             ` H. Peter Anvin
2014-04-22 18:03                                             ` Brian Gerst
2014-04-22 18:06                                               ` H. Peter Anvin
2014-04-22 18:17                                                 ` Brian Gerst
2014-04-22 18:51                                                   ` H. Peter Anvin
2014-04-22 19:55                                                     ` Brian Gerst
2014-04-22 20:17                                                       ` H. Peter Anvin
2014-04-22 23:08                                                         ` Brian Gerst
2014-04-22 23:39                                                     ` Andi Kleen
2014-04-22 23:40                                                       ` H. Peter Anvin
2014-04-22 17:11                                     ` H. Peter Anvin
2014-04-22 17:26                                       ` Borislav Petkov
2014-04-22 17:29                                         ` Andrew Lutomirski
2014-04-22 19:27                                           ` Borislav Petkov
2014-04-23  6:24                                     ` H. Peter Anvin
2014-04-23  8:57                                       ` Alexandre Julliard
2014-04-22 17:09                                   ` H. Peter Anvin
2014-04-22 17:20                                     ` Andrew Lutomirski
2014-04-22 17:24                                       ` H. Peter Anvin
2014-04-22 11:25   ` Borislav Petkov
2014-04-23  1:17   ` H. Peter Anvin
2014-04-23  1:23     ` Andrew Lutomirski
2014-04-23  1:42       ` H. Peter Anvin
2014-04-23 14:24         ` Boris Ostrovsky
2014-04-23 16:56           ` H. Peter Anvin
2014-04-28 13:04             ` Konrad Rzeszutek Wilk
2014-04-25 21:02     ` Konrad Rzeszutek Wilk
2014-04-25 21:16       ` H. Peter Anvin
2014-04-24  4:13   ` comex
2014-04-24  4:53     ` Andrew Lutomirski
2014-04-24 22:24       ` H. Peter Anvin
2014-04-24 22:31         ` Andrew Lutomirski
2014-04-24 22:37           ` H. Peter Anvin
2014-04-24 22:43             ` Andrew Lutomirski
2014-04-28 23:05       ` H. Peter Anvin
2014-04-28 23:08         ` H. Peter Anvin
2014-04-29  0:02           ` Andrew Lutomirski
2014-04-29  0:15             ` H. Peter Anvin
2014-04-29  0:20             ` Andrew Lutomirski
2014-04-29  2:38               ` H. Peter Anvin
2014-04-29  2:44                 ` H. Peter Anvin
2014-04-29  3:45                 ` H. Peter Anvin
2014-04-29  3:47                   ` H. Peter Anvin
2014-04-29  4:36                   ` H. Peter Anvin
2014-04-29  7:14                     ` H. Peter Anvin
2014-04-25 12:02   ` Pavel Machek
2014-04-25 21:20     ` H. Peter Anvin
     [not found] <CAM1qvvhTaChkceBawnZZKZYT6tURcVZQe3upq3dpn_S9wp0C-Q@mail.gmail.com>
2014-04-13 13:03 ` [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels Jan Janecek

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