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Commit 49b7f898 authored by Kees Cook's avatar Kees Cook
Browse files

mm: Use overflow helpers in kmalloc_array*() 



Instead of open-coded multiplication and bounds checking, use the new
overflow helper.

Suggested-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent ca90800a

include/linux/slab.h

+11 −6
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define	_LINUX_SLAB_H



#include <linux/gfp.h>

#include <linux/overflow.h>

#include <linux/types.h>

#include <linux/workqueue.h>
@@ -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)