Am 15.12.20 um 20:08 schrieb Andy Shevchenko:
On Tue, Dec 15, 2020 at 03:30:44PM +0100, Christian König wrote:
Am 15.12.20 um 04:03 schrieb Andrew Morton:
...
Question: Can the fact that __GFP_ZERO is effectively ignored cause an
information leak if new size is larger than old size and the array is
somehow copied to user space?
I think the answer is no, but just wanted to double check. Maybe we should
note that here.
kmalloc()/kmalloc_array()/etc has the same. Should it be mentioned there as well?
No, they don't. If kmalloc()/kmalloc_array() would ignore __GFP_ZERO we
would have quite a problem.
It is only krealloc()/krealloc_array() which ignore __GFP_ZERO when they
don't reallocate memory because newsize is smaller than oldsize. In
other words the freed up space is not cleared in any way.
Christian.
