From: Michael Ellerman <mpe@ellerman.id.au>
To: David Laight <David.Laight@ACULAB.COM>,
'Josh Poimboeuf' <jpoimboe@redhat.com>,
Kees Cook <keescook@chromium.org>
Cc: "linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>, Linux-MM <linux-mm@kvack.org>,
sparclinux <sparclinux@vger.kernel.org>, Jan Kara <jack@suse.cz>,
Christoph Lameter <cl@linux.com>,
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Pekka Enberg <penberg@kernel.org>,
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Joonsoo Kim <iamjoonsoo.kim@lge.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"David S. Miller" <davem@davemloft.net>
Subject: [kernel-hardening] RE: [PATCH v3 02/11] mm: Hardened usercopy
Date: Tue, 26 Jul 2016 12:09:14 +1000 [thread overview]
Message-ID: <87mvl5jgl1.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D5F502102@AcuExch.aculab.com>
David Laight <David.Laight@ACULAB.COM> writes:
> From: Josh Poimboeuf
>> Sent: 22 July 2016 18:46
>> >
>> > e.g. then if the pointer was in the thread_info, the second test would
>> > fail, triggering the protection.
>>
>> FWIW, this won't work right on x86 after Andy's
>> CONFIG_THREAD_INFO_IN_TASK patches get merged.
>
> What ends up in the 'thread_info' area?
It depends on the arch.
> If it contains the fp save area then programs like gdb may end up requesting
> copy_in/out directly from that area.
On the arches I've seen thread_info doesn't usually contain register save areas,
but if it did then it would be up to the arch helper to allow that copy to go
through.
However given thread_info generally contains lots of low level flags that would
be a good target for an attacker, the best way to cope with ptrace wanting to
copy to/from it would be to use a temporary, and prohibit copying directly
to/from thread_info - IMHO.
cheers
next prev parent reply other threads:[~2016-07-26 2:09 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-15 21:44 [kernel-hardening] [PATCH v3 00/11] mm: Hardened usercopy Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 01/11] mm: Implement stack frame object validation Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 02/11] mm: Hardened usercopy Kees Cook
2016-07-19 1:06 ` [kernel-hardening] " Laura Abbott
2016-07-19 18:48 ` Kees Cook
2016-07-19 22:00 ` [kernel-hardening] [PATCH] mm: Add is_migrate_cma_page Laura Abbott
2016-07-19 22:40 ` [kernel-hardening] " Kees Cook
2016-07-20 10:24 ` [kernel-hardening] Re: [PATCH v3 02/11] mm: Hardened usercopy Balbir Singh
2016-07-20 15:36 ` Laura Abbott
2016-07-19 1:52 ` Laura Abbott
2016-07-19 19:12 ` Kees Cook
2016-07-19 22:55 ` Kees Cook
2016-07-19 9:21 ` Christian Borntraeger
2016-07-19 19:31 ` Kees Cook
2016-07-19 20:14 ` Christian Borntraeger
2016-07-19 20:34 ` Kees Cook
2016-07-19 20:44 ` Christian Borntraeger
2016-07-21 6:52 ` Michael Ellerman
[not found] ` <5790711f.2350420a.b4287.2cc0SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-21 18:34 ` Kees Cook
2016-07-22 17:45 ` Josh Poimboeuf
2016-07-25 9:27 ` [kernel-hardening] " David Laight
2016-07-26 2:09 ` Michael Ellerman [this message]
2016-07-26 2:03 ` [kernel-hardening] " Michael Ellerman
2016-07-26 4:46 ` Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 03/11] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 04/11] ARM: uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 05/11] arm64/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 06/11] ia64/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 07/11] powerpc/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 08/11] sparc/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 09/11] s390/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 10/11] mm: SLAB hardened usercopy support Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 11/11] mm: SLUB " Kees Cook
2016-07-18 8:26 ` [kernel-hardening] Re: [PATCH v3 00/11] mm: Hardened usercopy Balbir Singh
2016-07-20 9:52 ` [kernel-hardening] " David Laight
2016-07-20 15:31 ` [kernel-hardening] " Kees Cook
2016-07-20 16:02 ` [kernel-hardening] " David Laight
2016-07-20 16:22 ` [kernel-hardening] " Rik van Riel
2016-07-20 17:44 ` Kees Cook
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