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Subject[PATCH 05/13] mm: Use array_size() helpers for kvmalloc()
Date
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
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