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From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Brian Gerst <brgerst@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, "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: Fri, 11 Apr 2014 11:46:46 -0700	[thread overview]
Message-ID: <53483896.9070404@linux.intel.com> (raw)
In-Reply-To: <CA+55aFwzvSiAGYfFb2R3JeVvh8_PQuOKJDrYP5C_3VQz2zhnBw@mail.gmail.com>

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.

	-hpa


  parent reply	other threads:[~2014-04-11 18:46 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     ` H. Peter Anvin [this message]
2014-04-14  7:27       ` [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels Ingo Molnar
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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