Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Kees Cook <keescook@chromium.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Kees Cook <keescook@chromium.org>,
        Christoph Lameter <cl@linux.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Waiman Long <longman@redhat.com>,
        Marco Elver <elver@google.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Roman Gushchin <guro@fb.com>, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH v3 0/3] Actually fix freelist pointer vs redzoning
Date:   Wed, 14 Oct 2020 20:37:09 -0700
Message-Id: <20201015033712.1491731-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

v3:
- fix commit messages to properly reflect the direction of the overwrite
- justify the less-than-word-size patch better
- add Acks
- move some Fixes up into the commit log as just references
v2: https://lore.kernel.org/lkml/20201009195411.4018141-1-keescook@chromium.org
v1: https://lore.kernel.org/lkml/20201008233443.3335464-1-keescook@chromium.org

This fixes redzoning vs the freelist pointer (both for middle-position
and very small caches). Both are "theoretical" fixes, in that I see no
evidence of such small-sized caches actually be used in the kernel, but
that's no reason to let the bugs continue to exist. :)

Note on patch 2: Christopher NAKed it, but I actually think this is a
reasonable thing to add -- the "too small" check is only made when built
with CONFIG_DEBUG_VM, so it *is* actually possible for someone to trip
over this directly, even if it would never make it into a released
kernel. I see no reason to just leave this foot-gun in place, though, so
we might as well just fix it too. (Which seems to be what Longman was
similarly supporting, IIUC.)

Anyway, if patch 2 stays NAKed, that's fine. It's entirely separable,
and the other 2 can land. :)

Thanks!

-Kees


Kees Cook (3):
  mm/slub: Clarify verification reporting
  mm/slub: Fix redzoning for small allocations
  mm/slub: Actually fix freelist pointer vs redzoning

 Documentation/vm/slub.rst | 10 +++++-----
 mm/slub.c                 | 36 +++++++++++++++---------------------
 2 files changed, 20 insertions(+), 26 deletions(-)

-- 
2.25.1