Date: Mon, 21 Dec 2015 19:40:34 -0800 From: Laura Abbott <laura@...bott.name> To: Christoph Lameter <cl@...ux.com>, Pekka Enberg <penberg@...nel.org>, David Rientjes <rientjes@...gle.com>, Joonsoo Kim <iamjoonsoo.kim@....com>, Andrew Morton <akpm@...ux-foundation.org> Cc: Laura Abbott <laura@...bott.name>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>, kernel-hardening@...ts.openwall.com Subject: [RFC][PATCH 0/7] Sanitization of slabs based on grsecurity/PaX Hi, This is a partial port of the PAX_MEMORY_SANITIZE feature. The concept is fairly simple: when memory is freed, existing data should be erased. This helps to reduce the impact of problems (e.g. 45a22f4 inotify: Fix reporting of cookies for inotify events e4514cb RDMA/cxgb3: Fix information leak in send_abort() your favorite use after free bug) The biggest change from PAX_MEMORY_SANTIIZE is that this feature sanitizes the SL[AOU]B allocators only. My plan is to work on the buddy allocator santization after this series gets picked up. A side effect of this is that allocations which go directly to the buddy allocator (i.e. large allocations) aren't sanitized. I'd like feedback about whether it's worth it to add sanitization on that path directly or just use the page allocator sanitization when that comes in. I also expanded the command line options, mostly for SLUB. Since SLUB has had so much tuning work done for performance, I added an option to only sanitize on the slow path. Freeing on only fast vs. slow path was most noticable in the bulk test cases. Overall, I saw impacts of 3% to 20% on various benchmarks when this feature was enabled. The overall impact of sanitize_slab=off seemed to be pretty negligable. This feature is similar to the debug feature of SLAB_POISON. I did consider trying to make that feature not related to debug. Ultimately, I concluded there was too much extra debug overhead and other features to make it worth it. Bike shed whatever you like. The Kconfig will probably end up in a separate sanitization Kconfig. All credit for the original work should be given to Brad Spengler and the PaX Team. Thanks, Laura Laura Abbott (7): mm/slab_common.c: Add common support for slab saniziation slub: Add support for sanitization slab: Add support for sanitization slob: Add support for sanitization mm: Mark several cases as SLAB_NO_SANITIZE mm: Add Kconfig option for slab sanitization lkdtm: Add READ_AFTER_FREE test drivers/misc/lkdtm.c | 29 ++++++++++++++++ fs/buffer.c | 2 +- fs/dcache.c | 2 +- include/linux/slab.h | 7 ++++ include/linux/slab_def.h | 4 +++ init/Kconfig | 48 ++++++++++++++++++++++++++ kernel/fork.c | 2 +- mm/rmap.c | 4 +-- mm/slab.c | 35 +++++++++++++++++++ mm/slab.h | 24 ++++++++++++- mm/slab_common.c | 53 ++++++++++++++++++++++++++++ mm/slob.c | 27 +++++++++++---- mm/slub.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++- net/core/skbuff.c | 4 +-- 14 files changed, 316 insertions(+), 15 deletions(-) -- 2.5.0
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.