Commit 776dee31 authored Nov 05, 2015 by Wang Long Committed by Alex Shi Apr 11, 2016

kasan: Fix a type conversion error



The current KASAN code can not 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>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit e0d57714394f5e2ce4e2f9bbebf48e3c7a7fd3be)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

parent 0c0922eb

mm/kasan/kasan.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -203,7 +203,7 @@ 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;