Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965439AbcJFIr5 (ORCPT ); Thu, 6 Oct 2016 04:47:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48549 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965019AbcJFIrx (ORCPT ); Thu, 6 Oct 2016 04:47:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Potapenko , Andrey Konovalov , Christoph Lameter , Dmitry Vyukov , "Steven Rostedt (Red Hat)" , Joonsoo Kim , Kostya Serebryany , Andrey Ryabinin , Kuthonuzo Luruo , Andrew Morton , Linus Torvalds Subject: [PATCH 4.7 090/141] mm, kasan: account for object redzone in SLUBs nearest_obj() Date: Thu, 6 Oct 2016 10:28:46 +0200 Message-Id: <20161006074452.591388745@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161006074448.608056610@linuxfoundation.org> References: <20161006074448.608056610@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2610 Lines: 74 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Potapenko commit c146a2b98eb5898eb0fab15a332257a4102ecae9 upstream. When looking up the nearest SLUB object for a given address, correctly calculate its offset if SLAB_RED_ZONE is enabled for that cache. Previously, when KASAN had detected an error on an object from a cache with SLAB_RED_ZONE set, the actual start address of the object was miscalculated, which led to random stacks having been reported. When looking up the nearest SLUB object for a given address, correctly calculate its offset if SLAB_RED_ZONE is enabled for that cache. Fixes: 7ed2f9e663854db ("mm, kasan: SLAB support") Link: http://lkml.kernel.org/r/1468347165-41906-2-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko Cc: Andrey Konovalov Cc: Christoph Lameter Cc: Dmitry Vyukov Cc: Steven Rostedt (Red Hat) Cc: Joonsoo Kim Cc: Kostya Serebryany Cc: Andrey Ryabinin Cc: Kuthonuzo Luruo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/slub_def.h | 10 ++++++---- mm/slub.c | 2 +- 2 files changed, 7 insertions(+), 5 deletions(-) --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -114,15 +114,17 @@ static inline void sysfs_slab_remove(str void object_err(struct kmem_cache *s, struct page *page, u8 *object, char *reason); +void *fixup_red_left(struct kmem_cache *s, void *p); + static inline void *nearest_obj(struct kmem_cache *cache, struct page *page, void *x) { void *object = x - (x - page_address(page)) % cache->size; void *last_object = page_address(page) + (page->objects - 1) * cache->size; - if (unlikely(object > last_object)) - return last_object; - else - return object; + void *result = (unlikely(object > last_object)) ? last_object : object; + + result = fixup_red_left(cache, result); + return result; } #endif /* _LINUX_SLUB_DEF_H */ --- a/mm/slub.c +++ b/mm/slub.c @@ -124,7 +124,7 @@ static inline int kmem_cache_debug(struc #endif } -static inline void *fixup_red_left(struct kmem_cache *s, void *p) +inline void *fixup_red_left(struct kmem_cache *s, void *p) { if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) p += s->red_left_pad;