From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752531AbcAFCLW (ORCPT ); Tue, 5 Jan 2016 21:11:22 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:35862 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbcAFCLT (ORCPT ); Tue, 5 Jan 2016 21:11:19 -0500 Subject: Re: [RFC][PATCH 5/7] mm: Mark several cases as SLAB_NO_SANITIZE To: Kees Cook References: <1450755641-7856-1-git-send-email-laura@labbott.name> <1450755641-7856-6-git-send-email-laura@labbott.name> Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Linux-MM , LKML , "kernel-hardening@lists.openwall.com" From: Laura Abbott Message-ID: <568C77C5.2090003@labbott.name> Date: Tue, 5 Jan 2016 18:11:17 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/5/16 4:21 PM, Kees Cook wrote: > On Mon, Dec 21, 2015 at 7:40 PM, Laura Abbott wrote: >> >> Sanitization is useful for security but comes at the cost of performance >> in clearing on free. Mark select caches as SLAB_NO_SANITIZE so >> sanitization will not happen under the default configuration. The > > Can you describe why these were selected? > These were the cases that existed in grsecurity. From looking, these seem to be performance critical caches that have a relatively lower risk. I'll adjust the commit text. >> kernel may be booted with the proper command line option to allow these >> caches to be sanitized. > > Might be good to specifically mention the command line used to > sanitize even these caches. Sure. > > -Kees Thanks, Laura > >> >> All credit for the original work should be given to Brad Spengler and >> the PaX Team. >> >> Signed-off-by: Laura Abbott >> --- >> This is the initial set of excludes that the grsecurity patches had. >> More may need to be added/removed as the series is tested. >> --- >> fs/buffer.c | 2 +- >> fs/dcache.c | 2 +- >> kernel/fork.c | 2 +- >> mm/rmap.c | 4 ++-- >> mm/slab.h | 2 +- >> net/core/skbuff.c | 16 ++++++++-------- >> 6 files changed, 14 insertions(+), 14 deletions(-) >> >> diff --git a/fs/buffer.c b/fs/buffer.c >> index 4f4cd95..f19e4ab 100644 >> --- a/fs/buffer.c >> +++ b/fs/buffer.c >> @@ -3417,7 +3417,7 @@ void __init buffer_init(void) >> bh_cachep = kmem_cache_create("buffer_head", >> sizeof(struct buffer_head), 0, >> (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| >> - SLAB_MEM_SPREAD), >> + SLAB_MEM_SPREAD|SLAB_NO_SANITIZE), >> NULL); >> >> /* >> diff --git a/fs/dcache.c b/fs/dcache.c >> index 5c33aeb..470f6be 100644 >> --- a/fs/dcache.c >> +++ b/fs/dcache.c >> @@ -3451,7 +3451,7 @@ void __init vfs_caches_init_early(void) >> void __init vfs_caches_init(void) >> { >> names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, >> - SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); >> + SLAB_NO_SANITIZE|SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); >> >> dcache_init(); >> inode_init(); >> diff --git a/kernel/fork.c b/kernel/fork.c >> index fce002e..35db9c3 100644 >> --- a/kernel/fork.c >> +++ b/kernel/fork.c >> @@ -1868,7 +1868,7 @@ void __init proc_caches_init(void) >> mm_cachep = kmem_cache_create("mm_struct", >> sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, >> SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); >> - vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); >> + vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_NO_SANITIZE); >> mmap_init(); >> nsproxy_cache_init(); >> } >> diff --git a/mm/rmap.c b/mm/rmap.c >> index b577fbb..74296d9 100644 >> --- a/mm/rmap.c >> +++ b/mm/rmap.c >> @@ -428,8 +428,8 @@ static void anon_vma_ctor(void *data) >> void __init anon_vma_init(void) >> { >> anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma), >> - 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor); >> - anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain, SLAB_PANIC); >> + 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC|SLAB_NO_SANITIZE, anon_vma_ctor); >> + anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain, SLAB_PANIC|SLAB_NO_SANITIZE); >> } >> >> /* >> diff --git a/mm/slab.h b/mm/slab.h >> index b54b636..6de99da 100644 >> --- a/mm/slab.h >> +++ b/mm/slab.h >> @@ -137,7 +137,7 @@ static inline unsigned long kmem_cache_flags(unsigned long object_size, >> >> /* Legal flag mask for kmem_cache_create(), for various configurations */ >> #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \ >> - SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS ) >> + SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS | SLAB_NO_SANITIZE) >> >> #if defined(CONFIG_DEBUG_SLAB) >> #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) >> diff --git a/net/core/skbuff.c b/net/core/skbuff.c >> index b2df375..1d499ea 100644 >> --- a/net/core/skbuff.c >> +++ b/net/core/skbuff.c >> @@ -3316,15 +3316,15 @@ done: >> void __init skb_init(void) >> { >> skbuff_head_cache = kmem_cache_create("skbuff_head_cache", >> - sizeof(struct sk_buff), >> - 0, >> - SLAB_HWCACHE_ALIGN|SLAB_PANIC, >> - NULL); >> + sizeof(struct sk_buff), >> + 0, >> + SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NO_SANITIZE, >> + NULL); >> skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", >> - sizeof(struct sk_buff_fclones), >> - 0, >> - SLAB_HWCACHE_ALIGN|SLAB_PANIC, >> - NULL); >> + sizeof(struct sk_buff_fclones), >> + 0, >> + SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NO_SANITIZE, >> + NULL); >> } >> >> /** >> -- >> 2.5.0 >> > > >