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From: Arnd Bergmann <arnd@arndb.de>
To: Rik van Riel <riel@redhat.com>
Cc: kernel-hardening@lists.openwall.com,
	Andy Lutomirski <luto@amacapital.net>,
	Jann Horn <jannh@google.com>, Andy Lutomirski <luto@kernel.org>,
	X86 ML <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
	Brian Gerst <brgerst@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [kernel-hardening] Re: [PATCH v3 06/13] fork: Add generic vmalloced stack support
Date: Tue, 21 Jun 2016 21:44:13 +0200	[thread overview]
Message-ID: <3742830.xcm4l8nxyl@wuerfel> (raw)
In-Reply-To: <1466533948.2756.56.camel@redhat.com>

On Tuesday, June 21, 2016 2:32:28 PM CEST Rik van Riel wrote:
> On Tue, 2016-06-21 at 10:13 -0700, Kees Cook wrote:
> > On Tue, Jun 21, 2016 at 9:59 AM, Andy Lutomirski <luto@amacapital.net
> > > wrote:
> > > 
> > > I'm tempted to explicitly disallow VM_NO_GUARD in the vmalloc
> > > range.
> > > It has no in-tree users for non-fixed addresses right now.
> > What about the lack of pre-range guard page? That seems like a
> > critical feature for this. 
> 
> If VM_NO_GUARD is disallowed, and every vmalloc area has
> a guard area behind it, then every subsequent vmalloc area
> will have a guard page ahead of it.
> 
> I think disallowing VM_NO_GUARD will be all that is required.
> 
> The only thing we may want to verify on the architectures that
> we care about is that there is nothing mapped immediately before
> the start of the vmalloc range, otherwise the first vmalloced
> area will not have a guard page below it.

FWIW, ARM has an 8MB guard area between the linear mapping of
physical memory and the start of the vmalloc area. I have not
checked any of the other architectures though.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Rik van Riel <riel@redhat.com>
Cc: kernel-hardening@lists.openwall.com,
	Andy Lutomirski <luto@amacapital.net>,
	Jann Horn <jannh@google.com>, Andy Lutomirski <luto@kernel.org>,
	X86 ML <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
	Brian Gerst <brgerst@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: Re: [PATCH v3 06/13] fork: Add generic vmalloced stack support
Date: Tue, 21 Jun 2016 21:44:13 +0200	[thread overview]
Message-ID: <3742830.xcm4l8nxyl@wuerfel> (raw)
In-Reply-To: <1466533948.2756.56.camel@redhat.com>

On Tuesday, June 21, 2016 2:32:28 PM CEST Rik van Riel wrote:
> On Tue, 2016-06-21 at 10:13 -0700, Kees Cook wrote:
> > On Tue, Jun 21, 2016 at 9:59 AM, Andy Lutomirski <luto@amacapital.net
> > > wrote:
> > > 
> > > I'm tempted to explicitly disallow VM_NO_GUARD in the vmalloc
> > > range.
> > > It has no in-tree users for non-fixed addresses right now.
> > What about the lack of pre-range guard page? That seems like a
> > critical feature for this. 
> 
> If VM_NO_GUARD is disallowed, and every vmalloc area has
> a guard area behind it, then every subsequent vmalloc area
> will have a guard page ahead of it.
> 
> I think disallowing VM_NO_GUARD will be all that is required.
> 
> The only thing we may want to verify on the architectures that
> we care about is that there is nothing mapped immediately before
> the start of the vmalloc range, otherwise the first vmalloced
> area will not have a guard page below it.

FWIW, ARM has an 8MB guard area between the linear mapping of
physical memory and the start of the vmalloc area. I have not
checked any of the other architectures though.

	Arnd

  reply	other threads:[~2016-06-21 19:50 UTC|newest]

Thread overview: 269+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-20 23:43 [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 02/13] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 03/13] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-21  9:53   ` Matt Fleming
2016-06-21  9:53     ` [kernel-hardening] " Matt Fleming
2016-06-21  9:53     ` Matt Fleming
2016-06-20 23:43 ` [PATCH v3 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-21  9:46   ` Vladimir Davydov
2016-06-21  9:46     ` [kernel-hardening] " Vladimir Davydov
2016-06-21  9:46     ` Vladimir Davydov
2016-06-21  9:46     ` Vladimir Davydov
2016-06-22  7:35   ` Michal Hocko
2016-06-22  7:35     ` [kernel-hardening] " Michal Hocko
2016-06-22  7:35     ` Michal Hocko
2016-06-22  7:35     ` Michal Hocko
2016-06-20 23:43 ` [PATCH v3 05/13] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-21  9:54   ` Vladimir Davydov
2016-06-21  9:54     ` [kernel-hardening] " Vladimir Davydov
2016-06-21  9:54     ` Vladimir Davydov
2016-06-21  9:54     ` Vladimir Davydov
2016-06-22  7:38   ` Michal Hocko
2016-06-22  7:38     ` [kernel-hardening] " Michal Hocko
2016-06-22  7:38     ` Michal Hocko
2016-06-22  7:38     ` Michal Hocko
2016-06-20 23:43 ` [PATCH v3 06/13] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-21  7:30   ` Jann Horn
2016-06-21  7:30     ` [kernel-hardening] " Jann Horn
2016-06-21  7:30     ` Jann Horn
2016-06-21 16:59     ` Andy Lutomirski
2016-06-21 16:59       ` [kernel-hardening] " Andy Lutomirski
2016-06-21 16:59       ` Andy Lutomirski
2016-06-21 17:13       ` Kees Cook
2016-06-21 17:13         ` [kernel-hardening] " Kees Cook
2016-06-21 17:13         ` Kees Cook
2016-06-21 17:28         ` Andy Lutomirski
2016-06-21 17:28           ` [kernel-hardening] " Andy Lutomirski
2016-06-21 17:28           ` Andy Lutomirski
2016-06-21 18:32         ` [kernel-hardening] " Rik van Riel
2016-06-21 18:32           ` Rik van Riel
2016-06-21 19:44           ` Arnd Bergmann [this message]
2016-06-21 19:44             ` Arnd Bergmann
2016-06-21 19:43             ` [kernel-hardening] " Andy Lutomirski
2016-06-21 19:43               ` Andy Lutomirski
2016-06-21 19:43               ` Andy Lutomirski
2016-07-11 17:00           ` [kernel-hardening] " Andrey Ryabinin
2016-06-20 23:43 ` [PATCH v3 07/13] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
2016-06-20 23:43   ` [kernel-hardening] " Andy Lutomirski
2016-06-20 23:43   ` Andy Lutomirski
2016-06-21  4:01 ` [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Linus Torvalds
2016-06-21  4:01   ` [kernel-hardening] " Linus Torvalds
2016-06-21  4:01   ` Linus Torvalds
2016-06-21 16:45   ` Andy Lutomirski
2016-06-21 16:45     ` [kernel-hardening] " Andy Lutomirski
2016-06-21 16:45     ` Andy Lutomirski
2016-06-21 17:16     ` Linus Torvalds
2016-06-21 17:16       ` [kernel-hardening] " Linus Torvalds
2016-06-21 17:16       ` Linus Torvalds
2016-06-21 17:27       ` Andy Lutomirski
2016-06-21 17:27         ` [kernel-hardening] " Andy Lutomirski
2016-06-21 17:27         ` Andy Lutomirski
2016-06-21 18:12         ` Kees Cook
2016-06-21 18:12           ` [kernel-hardening] " Kees Cook
2016-06-21 18:12           ` Kees Cook
2016-06-21 18:19           ` [kernel-hardening] " Rik van Riel
2016-06-21 18:19             ` Rik van Riel
2016-06-23  1:22   ` Andy Lutomirski
2016-06-23  1:22     ` [kernel-hardening] " Andy Lutomirski
2016-06-23  1:22     ` Andy Lutomirski
2016-06-23  6:02     ` Linus Torvalds
2016-06-23  6:02       ` [kernel-hardening] " Linus Torvalds
2016-06-23  6:02       ` Linus Torvalds
2016-06-23 14:31       ` Oleg Nesterov
2016-06-23 14:31         ` [kernel-hardening] " Oleg Nesterov
2016-06-23 14:31         ` Oleg Nesterov
2016-06-23 16:30         ` Linus Torvalds
2016-06-23 16:30           ` [kernel-hardening] " Linus Torvalds
2016-06-23 16:30           ` Linus Torvalds
2016-06-23 16:41           ` Andy Lutomirski
2016-06-23 16:41             ` [kernel-hardening] " Andy Lutomirski
2016-06-23 16:41             ` Andy Lutomirski
2016-06-23 17:10             ` Oleg Nesterov
2016-06-23 17:10               ` [kernel-hardening] " Oleg Nesterov
2016-06-23 17:10               ` Oleg Nesterov
2016-09-06 16:19             ` Jann Horn
2016-09-06 16:19               ` [kernel-hardening] " Jann Horn
2016-09-06 16:19               ` Jann Horn
2016-09-06 16:40               ` Andy Lutomirski
2016-09-06 16:40                 ` [kernel-hardening] " Andy Lutomirski
2016-09-06 16:40                 ` Andy Lutomirski
2016-06-23 17:03           ` Oleg Nesterov
2016-06-23 17:03             ` [kernel-hardening] " Oleg Nesterov
2016-06-23 17:03             ` Oleg Nesterov
2016-06-23 17:44             ` Linus Torvalds
2016-06-23 17:44               ` [kernel-hardening] " Linus Torvalds
2016-06-23 17:44               ` Linus Torvalds
2016-06-23 17:52               ` Linus Torvalds
2016-06-23 17:52                 ` [kernel-hardening] " Linus Torvalds
2016-06-23 17:52                 ` Linus Torvalds
2016-06-23 18:00                 ` Kees Cook
2016-06-23 18:00                   ` [kernel-hardening] " Kees Cook
2016-06-23 18:00                   ` Kees Cook
2016-06-23 18:54                   ` Peter Zijlstra
2016-06-23 18:54                     ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:54                     ` Peter Zijlstra
2016-06-23 18:12                 ` Oleg Nesterov
2016-06-23 18:12                   ` [kernel-hardening] " Oleg Nesterov
2016-06-23 18:12                   ` Oleg Nesterov
2016-06-23 18:55                   ` Peter Zijlstra
2016-06-23 18:55                     ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:55                     ` Peter Zijlstra
2016-06-23 18:46                 ` Linus Torvalds
2016-06-23 18:46                   ` [kernel-hardening] " Linus Torvalds
2016-06-23 18:46                   ` Linus Torvalds
2016-06-23 19:08                   ` Andy Lutomirski
2016-06-23 19:08                     ` [kernel-hardening] " Andy Lutomirski
2016-06-23 19:08                     ` Andy Lutomirski
2016-06-23 18:53                 ` Peter Zijlstra
2016-06-23 18:53                   ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:53                   ` Peter Zijlstra
2016-06-23 19:09                   ` Andy Lutomirski
2016-06-23 19:09                     ` [kernel-hardening] " Andy Lutomirski
2016-06-23 19:09                     ` Andy Lutomirski
2016-06-23 19:13                     ` Peter Zijlstra
2016-06-23 19:13                       ` [kernel-hardening] " Peter Zijlstra
2016-06-23 19:13                       ` Peter Zijlstra
2016-06-23 19:17                   ` Linus Torvalds
2016-06-23 19:17                     ` [kernel-hardening] " Linus Torvalds
2016-06-23 19:17                     ` Linus Torvalds
2016-06-24  6:17                     ` Linus Torvalds
2016-06-24  6:17                       ` [kernel-hardening] " Linus Torvalds
2016-06-24  6:17                       ` Linus Torvalds
2016-06-24 12:25                       ` Brian Gerst
2016-06-24 12:25                         ` [kernel-hardening] " Brian Gerst
2016-06-24 12:25                         ` Brian Gerst
2016-06-24 17:21                         ` Linus Torvalds
2016-06-24 17:21                           ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:21                           ` Linus Torvalds
2016-06-24 17:40                           ` Linus Torvalds
2016-06-24 17:40                             ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:40                             ` Linus Torvalds
2016-06-24 17:47                             ` Andy Lutomirski
2016-06-24 17:47                               ` [kernel-hardening] " Andy Lutomirski
2016-06-24 17:47                               ` Andy Lutomirski
2016-06-24 17:56                               ` Linus Torvalds
2016-06-24 17:56                                 ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:56                                 ` Linus Torvalds
2016-06-24 18:36                                 ` Andy Lutomirski
2016-06-24 18:36                                   ` [kernel-hardening] " Andy Lutomirski
2016-06-24 18:36                                   ` Andy Lutomirski
2016-06-24 17:51                             ` Linus Torvalds
2016-06-24 17:51                               ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:51                               ` Linus Torvalds
2016-06-24 18:11                               ` Linus Torvalds
2016-06-24 18:11                                 ` [kernel-hardening] " Linus Torvalds
2016-06-24 18:11                                 ` Linus Torvalds
2016-06-24 20:25                                 ` Josh Poimboeuf
2016-06-24 20:25                                   ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 20:25                                   ` Josh Poimboeuf
2016-06-24 20:51                                   ` Josh Poimboeuf
2016-06-24 20:51                                     ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 20:51                                     ` Josh Poimboeuf
2016-06-24 20:53                                     ` Andy Lutomirski
2016-06-24 20:53                                       ` [kernel-hardening] " Andy Lutomirski
2016-06-24 20:53                                       ` Andy Lutomirski
2016-06-24 21:06                                     ` Linus Torvalds
2016-06-24 21:06                                       ` [kernel-hardening] " Linus Torvalds
2016-06-24 21:06                                       ` Linus Torvalds
2016-06-24 21:25                                       ` Andy Lutomirski
2016-06-24 21:25                                         ` [kernel-hardening] " Andy Lutomirski
2016-06-24 21:25                                         ` Andy Lutomirski
2016-06-24 21:32                                         ` Linus Torvalds
2016-06-24 21:32                                           ` [kernel-hardening] " Linus Torvalds
2016-06-24 21:32                                           ` Linus Torvalds
2016-06-24 21:34                                           ` Andy Lutomirski
2016-06-24 21:34                                             ` [kernel-hardening] " Andy Lutomirski
2016-06-24 21:34                                             ` Andy Lutomirski
2016-06-25  2:41                                             ` Linus Torvalds
2016-06-25  2:41                                               ` [kernel-hardening] " Linus Torvalds
2016-06-25  2:41                                               ` Linus Torvalds
2016-06-25 23:19                                               ` Andy Lutomirski
2016-06-25 23:19                                                 ` [kernel-hardening] " Andy Lutomirski
2016-06-25 23:19                                                 ` Andy Lutomirski
2016-06-25 23:30                                                 ` Andy Lutomirski
2016-06-25 23:30                                                   ` [kernel-hardening] " Andy Lutomirski
2016-06-25 23:30                                                   ` Andy Lutomirski
2016-06-26  1:23                                                   ` Linus Torvalds
2016-06-26  1:23                                                     ` [kernel-hardening] " Linus Torvalds
2016-06-26  1:23                                                     ` Linus Torvalds
2016-06-23 18:52               ` Oleg Nesterov
2016-06-23 18:52                 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 18:52                 ` Oleg Nesterov
2016-06-24 14:05                 ` Michal Hocko
2016-06-24 14:05                   ` [kernel-hardening] " Michal Hocko
2016-06-24 14:05                   ` Michal Hocko
2016-06-24 15:06                   ` Michal Hocko
2016-06-24 15:06                     ` [kernel-hardening] " Michal Hocko
2016-06-24 15:06                     ` Michal Hocko
2016-06-24 15:06                     ` Michal Hocko
2016-06-24 20:22                     ` Oleg Nesterov
2016-06-24 20:22                       ` [kernel-hardening] " Oleg Nesterov
2016-06-24 20:22                       ` Oleg Nesterov
2016-06-27 10:36                       ` Michal Hocko
2016-06-27 10:36                         ` [kernel-hardening] " Michal Hocko
2016-06-27 10:36                         ` Michal Hocko
2016-06-23 19:11         ` Peter Zijlstra
2016-06-23 19:11           ` [kernel-hardening] " Peter Zijlstra
2016-06-23 19:11           ` Peter Zijlstra
2016-06-23 19:34           ` Linus Torvalds
2016-06-23 19:34             ` [kernel-hardening] " Linus Torvalds
2016-06-23 19:34             ` Linus Torvalds
2016-06-23 19:46             ` Peter Zijlstra
2016-06-23 19:46               ` [kernel-hardening] " Peter Zijlstra
2016-06-23 19:46               ` Peter Zijlstra
2016-06-21  9:24 ` Arnd Bergmann
2016-06-21  9:24   ` [kernel-hardening] " Arnd Bergmann
2016-06-21  9:24   ` Arnd Bergmann
2016-06-21 17:16   ` Kees Cook
2016-06-21 17:16     ` [kernel-hardening] " Kees Cook
2016-06-21 17:16     ` Kees Cook
2016-06-21 18:02     ` [kernel-hardening] " Rik van Riel
2016-06-21 18:02       ` Rik van Riel
2016-06-21 18:05       ` [kernel-hardening] " Andy Lutomirski
2016-06-21 18:05         ` Andy Lutomirski
2016-06-21 18:05         ` Andy Lutomirski
2016-06-21 19:47     ` Arnd Bergmann
2016-06-21 19:47       ` [kernel-hardening] " Arnd Bergmann
2016-06-21 19:47       ` Arnd Bergmann
2016-06-21 19:47       ` Andy Lutomirski
2016-06-21 19:47         ` [kernel-hardening] " Andy Lutomirski
2016-06-21 19:47         ` Andy Lutomirski
2016-06-21 20:18         ` Kees Cook
2016-06-21 20:18           ` [kernel-hardening] " Kees Cook
2016-06-21 20:18           ` Kees Cook

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