[PATCH master 10/23] include: linux/slab: fix possible overflow in kmalloc_array

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

If we are unlucky, n * size would overflow size_t and we'll instead
allocate a small truncated value, which may lead to memory corruption.

Fix this by using size_mul, which saturates at SIZE_MAX.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 include/linux/slab.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index dc80808938f4..36b93bdd2f1b 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -4,6 +4,7 @@
 #define _LINUX_SLAB_H
 
 #include <malloc.h>
+#include <linux/overflow.h>
 #include <linux/string.h>
 
 #define SLAB_CONSISTENCY_CHECKS	0
@@ -98,7 +99,7 @@ static inline void *kzalloc(size_t size, gfp_t flags)
  */
 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 {
-	return kmalloc(n * size, flags);
+	return kmalloc(size_mul(n, size), flags);
 }
 
 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
-- 
2.39.2