From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 459506B0580 for ; Wed, 9 May 2018 16:02:38 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id x21so10009603pfn.23 for ; Wed, 09 May 2018 13:02:38 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id b15-v6sor4280225plk.105.2018.05.09.13.02.37 for (Google Transport Security); Wed, 09 May 2018 13:02:37 -0700 (PDT) From: Kees Cook Subject: [PATCH v2 4/6] mm: Use overflow helpers in kmalloc_array*() Date: Wed, 9 May 2018 13:02:21 -0700 Message-Id: <20180509200223.22451-5-keescook@chromium.org> In-Reply-To: <20180509200223.22451-1-keescook@chromium.org> References: <20180509200223.22451-1-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: Kees Cook , Rasmus Villemoes , Matthew Wilcox , LKML , Linux-MM , Kernel Hardening Instead of open-coded multiplication and bounds checking, use the new overflow helper. Signed-off-by: Kees Cook --- include/linux/slab.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 81ebd71f8c03..4d759e1ddc33 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -13,6 +13,7 @@ #define _LINUX_SLAB_H #include +#include #include #include @@ -624,11 +625,13 @@ int memcg_update_all_caches(int num_memcgs); */ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) { - if (size != 0 && n > SIZE_MAX / size) + size_t bytes; + + if (unlikely(check_mul_overflow(n, size, &bytes))) return NULL; if (__builtin_constant_p(n) && __builtin_constant_p(size)) - return kmalloc(n * size, flags); - return __kmalloc(n * size, flags); + return kmalloc(bytes, flags); + return __kmalloc(bytes, flags); } /** @@ -657,11 +660,13 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long); static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags, int node) { - if (size != 0 && n > SIZE_MAX / size) + size_t bytes; + + if (unlikely(check_mul_overflow(n, size, &bytes))) return NULL; if (__builtin_constant_p(n) && __builtin_constant_p(size)) - return kmalloc_node(n * size, flags, node); - return __kmalloc_node(n * size, flags, node); + return kmalloc_node(bytes, flags, node); + return __kmalloc_node(bytes, flags, node); } static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node) -- 2.17.0