From: Laura Abbott <labbott@redhat.com>
To: Balbir Singh <bsingharora@gmail.com>, Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Daniel Micay <danielmicay@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Rik van Riel <riel@redhat.com>,
Casey Schaufler <casey@schaufler-ca.com>,
PaX Team <pageexec@freemail.hu>,
Brad Spengler <spender@grsecurity.net>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
"David S. Miller" <davem@davemloft.net>,
"x86@kernel.org" <x86@kernel.org>,
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"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>
Subject: [kernel-hardening] Re: [PATCH v3 02/11] mm: Hardened usercopy
Date: Wed, 20 Jul 2016 08:36:38 -0700 [thread overview]
Message-ID: <2aabe10d-2ccb-2ba6-18bb-b7f52d70d36c@redhat.com> (raw)
In-Reply-To: <1469010283.2800.5.camel@gmail.com>
On 07/20/2016 03:24 AM, Balbir Singh wrote:
> On Tue, 2016-07-19 at 11:48 -0700, Kees Cook wrote:
>> On Mon, Jul 18, 2016 at 6:06 PM, Laura Abbott <labbott@redhat.com> wrote:
>>>
>>> On 07/15/2016 02:44 PM, Kees Cook wrote:
>>>
>>> This doesn't work when copying CMA allocated memory since CMA purposely
>>> allocates larger than a page block size without setting head pages.
>>> Given CMA may be used with drivers doing zero copy buffers, I think it
>>> should be permitted.
>>>
>>> Something like the following lets it pass (I can clean up and submit
>>> the is_migrate_cma_page APIs as a separate patch for review)
>> Yeah, this would be great. I'd rather use an accessor to check this
>> than a direct check for MIGRATE_CMA.
>>
>>> */
>>> for (; ptr <= end ; ptr += PAGE_SIZE, page = virt_to_head_page(ptr))
>>> {
>>> - if (!PageReserved(page))
>>> + if (!PageReserved(page) && !is_migrate_cma_page(page))
>>> return "<spans multiple pages>";
>>> }
>> Yeah, I'll modify this a bit so that which type it starts as is
>> maintained for all pages (rather than allowing to flip back and forth
>> -- even though that is likely impossible).
>>
> Sorry, I completely missed the MIGRATE_CMA bits. Could you clarify if you
> caught this in testing/review?
>
> Balbir Singh.
>
I caught it while looking at the code and then wrote a test case to confirm
I was correct because I wasn't sure how to easily find an in tree user.
Thanks,
Laura
next prev parent reply other threads:[~2016-07-20 15:36 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 [this message]
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
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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