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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 5/5] arm64: add KASan support
Date: Mon, 24 Aug 2015 18:47:36 +0100	[thread overview]
Message-ID: <20150824174736.GD7557@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <CAPAsAGwji7FpUJK9O=FWYN15-rJkYMQyOt9W9ncdY9uLybxkiA@mail.gmail.com>

On Mon, Aug 24, 2015 at 05:15:22PM +0300, Andrey Ryabinin wrote:
> Yes, ~130Mb (3G/1G split) should work. 512Mb shadow is optional.
> The only advantage of 512Mb shadow is better handling of user memory
> accesses bugs
> (access to user memory without copy_from_user/copy_to_user/strlen_user etc API).

No need for that to be handed by KASan.  I have patches in linux-next,
now acked by Will, which prevent the kernel accessing userspace with
zero memory footprint.  No need for remapping, we have a way to quickly
turn off access to userspace mapped pages on non-LPAE 32-bit CPUs.
(LPAE is not supported yet - Catalin will be working on that using the
hooks I'm providing once he returns.)

This isn't a debugging thing, it's a security hardening thing.  Some
use-after-free bugs are potentially exploitable from userspace.  See
the recent blackhat conference paper.

-- 
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.

  parent reply	other threads:[~2015-08-24 17:47 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-15 13:58 [PATCH v2 0/5] KASan for arm64 Andrey Ryabinin
2015-05-15 13:59 ` [PATCH v2 1/5] kasan, x86: move KASAN_SHADOW_OFFSET to the arch Kconfig Andrey Ryabinin
2015-05-16 11:27   ` Paul Bolle
2015-05-18  7:43     ` Andrey Ryabinin
2015-05-18  8:34       ` Paul Bolle
2015-05-15 13:59 ` [PATCH v2 2/5] x86: kasan: fix types in kasan page tables declarations Andrey Ryabinin
2015-05-15 13:59 ` [PATCH v2 3/5] x86: kasan: generalize populate_zero_shadow() code Andrey Ryabinin
2015-05-15 13:59 ` [PATCH v2 4/5] kasan, x86: move populate_zero_shadow() out of arch directory Andrey Ryabinin
2015-05-15 13:59 ` [PATCH v2 5/5] arm64: add KASan support Andrey Ryabinin
2015-05-26 13:35   ` Linus Walleij
2015-05-26 14:12     ` Andrey Ryabinin
2015-05-26 14:22       ` Andrey Ryabinin
2015-05-26 20:28         ` Linus Walleij
2015-05-27 12:40   ` Linus Walleij
2015-06-11 13:39   ` Linus Walleij
2015-06-12 18:14     ` Andrey Ryabinin
2015-06-13 15:25       ` Linus Walleij
2015-06-17 21:32         ` Andrey Ryabinin
2015-07-21 10:36           ` Linus Walleij
2015-07-21 14:27             ` Andrey Ryabinin
2015-07-21 21:27               ` Linus Walleij
2015-07-22 17:54                 ` Andrey Ryabinin
2015-08-19 12:14                   ` Linus Walleij
2015-08-19 14:51                     ` Andrey Ryabinin
2015-08-24 13:02                       ` Linus Walleij
2015-08-24 13:15                 ` Russell King - ARM Linux
2015-08-24 13:45                   ` Linus Walleij
2015-08-24 14:15                     ` Andrey Ryabinin
2015-08-24 15:44                       ` Vladimir Murzin
2015-08-24 16:00                         ` Andrey Ryabinin
2015-08-24 16:16                           ` Vladimir Murzin
2015-08-24 16:18                             ` Andrey Ryabinin
2015-08-24 17:47                       ` Russell King - ARM Linux [this message]
2015-08-25  9:15                         ` Will Deacon
2015-07-08 15:48   ` Catalin Marinas
2015-07-10 17:11     ` Andrey Ryabinin
2015-07-14 15:04       ` Catalin Marinas
2015-07-15  8:55         ` Andrey Ryabinin
2015-07-15 16:37           ` Catalin Marinas
2015-07-16 15:30             ` Andrey Ryabinin
2015-07-16 16:03               ` Catalin Marinas
2015-07-17 13:13                 ` Andrey Ryabinin

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