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From: "Reshetova, Elena" <elena.reshetova@intel.com>
To: Kees Cook <keescook@chromium.org>
Cc: "kernel-hardening@lists.openwall.com"
	<kernel-hardening@lists.openwall.com>,
	Hans Liljestrand <ishkamiel@gmail.com>,
	David Windsor <dwindsor@gmail.com>
Subject: [kernel-hardening] RE: [RFC PATCH 02/13] percpu-refcount: leave atomic counter unprotected
Date: Tue, 4 Oct 2016 06:24:29 +0000	[thread overview]
Message-ID: <2236FBA76BA1254E88B949DDB74E612B41BDAB84@IRSMSX102.ger.corp.intel.com> (raw)
In-Reply-To: <CAGXu5jJnJODOzv4Yk=c-n9wA=hP=qza57q1EBcD4sJboVqXr3g@mail.gmail.com>

On Sun, Oct 2, 2016 at 11:41 PM, Elena Reshetova <elena.reshetova@intel.com> wrote:
> From: Hans Liljestrand <ishkamiel@gmail.com>
>
> This is a temporary solution, and a deviation from the PaX/Grsecurity 
> implementation where the counter in question is protected against 
> overflows. That however necessitates decreasing the PERCPU_COUNT_BIAS 
> which is used in lib/percpu-refcount.c. Such a change effectively cuts 
> the safe counter range down by half, and still allows the counter to, 
> without warning, prematurely reach zero (which is what the bias aims 
> to prevent).

>It might be useful to include a link to the earlier discussions that led to this solution.

Big part of it was in private emails, not sure how to reference that. Maybe we can just add more explanation here?

  reply	other threads:[~2016-10-04  6:24 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-03  6:41 [kernel-hardening] [RFC PATCH 00/13] HARDENING_ATOMIC feature Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 01/13] Add architecture independent hardened atomic base Elena Reshetova
2016-10-03 21:10   ` [kernel-hardening] " Kees Cook
2016-10-03 21:26     ` David Windsor
2016-10-03 21:38       ` Kees Cook
2016-10-04  7:05         ` [kernel-hardening] " Reshetova, Elena
2016-10-05 15:37           ` [kernel-hardening] " Dave Hansen
2016-10-04  7:07         ` [kernel-hardening] " Reshetova, Elena
2016-10-04  6:54       ` Reshetova, Elena
2016-10-04  7:23       ` Reshetova, Elena
2016-10-12  8:26     ` [kernel-hardening] " AKASHI Takahiro
2016-10-12 17:25       ` Reshetova, Elena
2016-10-12 22:50         ` Kees Cook
2016-10-13 14:31           ` Hans Liljestrand
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 02/13] percpu-refcount: leave atomic counter unprotected Elena Reshetova
2016-10-03 21:12   ` [kernel-hardening] " Kees Cook
2016-10-04  6:24     ` Reshetova, Elena [this message]
2016-10-04 13:06       ` Hans Liljestrand
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 03/13] kernel: identify wrapping atomic usage Elena Reshetova
2016-10-03 21:13   ` [kernel-hardening] " Kees Cook
2016-10-04  6:28     ` [kernel-hardening] " Reshetova, Elena
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 04/13] mm: " Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 05/13] fs: " Elena Reshetova
2016-10-03 21:57   ` Jann Horn
2016-10-03 22:21     ` Kees Cook
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 06/13] net: " Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 07/13] net: atm: " Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 08/13] security: " Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 09/13] drivers: identify wrapping atomic usage (part 1/2) Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 10/13] drivers: identify wrapping atomic usage (part 2/2) Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 11/13] x86: identify wrapping atomic usage Elena Reshetova
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 12/13] x86: x86 implementation for HARDENED_ATOMIC Elena Reshetova
2016-10-03  9:47   ` Jann Horn
2016-10-04  7:15     ` Reshetova, Elena
2016-10-04 12:46       ` Jann Horn
2016-10-03 19:27   ` Dave Hansen
2016-10-03 22:49     ` David Windsor
2016-10-04 12:41     ` Jann Horn
2016-10-04 18:51       ` Kees Cook
2016-10-04 19:48         ` Jann Horn
2016-10-05 15:39       ` Dave Hansen
2016-10-05 16:18         ` Jann Horn
2016-10-05 16:32           ` Dave Hansen
2016-10-03 21:29   ` [kernel-hardening] " Kees Cook
2016-10-03  6:41 ` [kernel-hardening] [RFC PATCH 13/13] lkdtm: add tests for atomic over-/underflow Elena Reshetova
2016-10-03 21:35   ` [kernel-hardening] " Kees Cook
2016-10-04  6:27     ` [kernel-hardening] " Reshetova, Elena
2016-10-04  6:40       ` [kernel-hardening] " Hans Liljestrand
2016-10-03  8:14 ` [kernel-hardening] [RFC PATCH 00/13] HARDENING_ATOMIC feature AKASHI Takahiro
2016-10-03  8:13   ` Reshetova, Elena
2016-10-03 21:01 ` [kernel-hardening] " Kees Cook

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