[PATCH 2/2] kasan: Fix a type conversion error

From	Wang Long <long.wanglong@huawei.com>
Newsgroups	linux.kernel
Subject	[PATCH 2/2] kasan: Fix a type conversion error
Date	2015-09-09 06:10 +0200
Message-ID	<q6ERP-8s-5@gated-at.bofh.it> (permalink)
References	<q6ERP-8s-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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The current KASAN code can find the following out-of-bounds
bugs:
	char *ptr;
	ptr = kmalloc(8, GFP_KERNEL);
	memset(ptr+7, 0, 2);

the cause of the problem is the type conversion error in
*memory_is_poisoned_n* function. So this patch fix that.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
---
 mm/kasan/kasan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 7b28e9c..5d65d06 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -204,7 +204,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr,
 		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
 
 		if (unlikely(ret != (unsigned long)last_shadow ||
-			((last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
+			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
 			return true;
 	}
 	return false;
-- 
1.8.3.4

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[PATCH 2/2] kasan: Fix a type conversion error Wang Long <long.wanglong@huawei.com> - 2015-09-09 06:10 +0200
  Re: [PATCH 2/2] kasan: Fix a type conversion error Vladimir Murzin <vladimir.murzin@arm.com> - 2015-09-09 11:10 +0200
    Re: [PATCH 2/2] kasan: Fix a type conversion error "long.wanglong" <long.wanglong@huawei.com> - 2015-09-09 11:40 +0200
  Re: [PATCH 2/2] kasan: Fix a type conversion error Andrey Ryabinin <ryabinin.a.a@gmail.com> - 2015-09-09 11:50 +0200
    Re: [PATCH 2/2] kasan: Fix a type conversion error "long.wanglong" <long.wanglong@huawei.com> - 2015-09-09 12:30 +0200

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