Re: [PATCH for-next] RDMA/core: Check invalid QP state for ib_modify_qp_is_ok()

[liweihang <liweihang@huawei.com>]

On 2021/3/22 13:47, Leon Romanovsky wrote:
> On Mon, Mar 22, 2021 at 03:29:09AM +0000, liweihang wrote:
>> On 2021/3/20 17:34, Leon Romanovsky wrote:
>>> On Fri, Mar 19, 2021 at 05:02:25PM +0800, Weihang Li wrote:
>>>> From: Xi Wang <wangxi11@huawei.com>
>>>>
>>>> Out-of-bounds may occur in 'qp_state_table' when the caller passing wrong
>>>> QP state value.
>>> How is it possible? Do you have call stack to support it?
>>>
>>> Thanks
>>>
>> ib_modify_qp_is_ok() is exported, I think any kernel modules can pass in
>> invalid QP state. Should we check it in such case?
> No, it is caller responsibility to supply valid input.
> In general case, for the kernel code, it can be seen as anti-pattern
> if in-kernel API performs input sanity check.
> 
> You can add WARN_ON() if you want to catch programmers errors earlier.
> However, I'm skeptical if it is really needed here. 
> 
> Thanks
> 

Hi Leon,

By the way, we made this change because we noticed that ib_event_msg() and
ib_wc_status_msg() that tries to access an array performs input check in the
same file. Is there anything different between these kernel APIs? Or there is
some other reasons?

Thanks,
Weihang