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From: Kees Cook <keescook@chromium.org>
To: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	kernel-hardening@lists.openwall.com
Subject: [PATCH 05/13] mm: Use array_size() helpers for kvmalloc()
Date: Tue,  8 May 2018 17:42:21 -0700	[thread overview]
Message-ID: <20180509004229.36341-6-keescook@chromium.org> (raw)
In-Reply-To: <20180509004229.36341-1-keescook@chromium.org>

Instead of open-coded multiplication, use the new array_size() helper
to detect overflow in kvmalloc()-family functions.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/mm.h      | 6 +++---
 include/linux/vmalloc.h | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ac1f06a4be6..c97ed9aa3412 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -25,6 +25,7 @@
 #include <linux/err.h>
 #include <linux/page_ref.h>
 #include <linux/memremap.h>
+#include <linux/overflow.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -560,10 +561,9 @@ static inline void *kvzalloc(size_t size, gfp_t flags)
 
 static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
 {
-	if (size != 0 && n > SIZE_MAX / size)
-		return NULL;
+	size_t bytes = array_size(n, size);
 
-	return kvmalloc(n * size, flags);
+	return kvmalloc(bytes, flags);
 }
 
 extern void kvfree(const void *addr);
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 1e5d8c392f15..398e9c95cd61 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -8,6 +8,7 @@
 #include <linux/llist.h>
 #include <asm/page.h>		/* pgprot_t */
 #include <linux/rbtree.h>
+#include <linux/overflow.h>
 
 struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
 struct notifier_block;		/* in notifier.h */
-- 
2.17.0

  parent reply	other threads:[~2018-05-09  0:42 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09  0:42 [RFC][PATCH 00/13] Provide saturating helpers for allocation Kees Cook
2018-05-09  0:42 ` [PATCH 01/13] compiler.h: enable builtin overflow checkers and add fallback code Kees Cook
2018-05-09  0:42 ` [PATCH 02/13] lib: add runtime test of check_*_overflow functions Kees Cook
2018-05-09  0:42 ` [PATCH 03/13] overflow.h: Add allocation size calculation helpers Kees Cook
2018-05-09 18:27   ` Rasmus Villemoes
2018-05-09 18:49     ` Kees Cook
2018-05-09  0:42 ` [PATCH 04/13] mm: Use array_size() helpers for kmalloc() Kees Cook
2018-05-09 11:34   ` Matthew Wilcox
2018-05-09 17:58     ` Kees Cook
2018-05-09 18:00     ` Rasmus Villemoes
2018-05-09 18:07       ` Kees Cook
2018-05-09 18:39         ` Rasmus Villemoes
2018-05-09  0:42 ` Kees Cook [this message]
2018-05-09  0:42 ` [PATCH 06/13] treewide: Use struct_size() for kmalloc()-family Kees Cook
2018-05-09  0:42 ` [PATCH 07/13] treewide: Use struct_size() for vmalloc()-family Kees Cook
2018-05-09  0:42 ` [PATCH 08/13] treewide: Use struct_size() for devm_kmalloc() and friends Kees Cook
2018-05-09  0:42 ` [PATCH 09/13] treewide: Use array_size() for kmalloc()-family Kees Cook
2018-05-09  0:42 ` [PATCH 10/13] treewide: Use array_size() for kmalloc()-family, leftovers Kees Cook
2018-05-09  0:42 ` [PATCH 11/13] treewide: Use array_size() for vmalloc() Kees Cook
2018-05-09  0:42 ` [PATCH 12/13] treewide: Use array_size() for devm_*alloc()-like Kees Cook
2018-05-09  0:42 ` [PATCH 13/13] treewide: Use array_size() for devm_*alloc()-like, leftovers Kees Cook
2018-05-09 16:08 ` [RFC][PATCH 00/13] Provide saturating helpers for allocation Laura Abbott
2018-05-09 17:01   ` Kees Cook

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