Re: [PATCH] staging: greybus: fix possible null-ptr-deref in gb_audio_manager_get_module()

["yiyang (D)" <yiyang13@huawei.com>]

On 2024/10/28 20:46, Alex Elder wrote:
> On 10/26/24 5:50 AM, Dan Carpenter wrote:
>> On Sat, Oct 26, 2024 at 08:11:53AM +0000, Yi Yang wrote:
>>> The gb_audio_manager_get_module() is EXPORT_SYMBOL, and will return NULL
>>> when incoming parameter id < 0, fix possible null-ptr-deref by add check
>>> for return value.
>>>
>>> Fixes: 8db00736d365 ("greybus: audio: Add Audio Manager")
>>> Signed-off-by: Yi Yang <yiyang13@huawei.com>
>>
>> Where is gb_audio_manager_get_module() called from?  So far as I can 
>> see it's
>> never used.  Why not just delete it?
>>
>> regards,
>> dan carpenter
> 
> I agree with this.  I suspected all callers might have guaranteed
> that the "id" value passed would be always valid, but... there are
> no callers.
> 
> It is a simple function, and could be added back again if it is
> needed in the future (possibly even by reverting the commit that
> removes it).
> 
> If you do this, please remove gb_audio_put_module() in the same
> patch.  It too has no callers.
> 
> Thank you.
> 
>                      -Alex
> 
> .

I tried to find the caller before I modified it, but unfortunately I 
didn't find the caller, so I suspect some non-kernel driver code will 
try to call this functions.

I just found this problem while reading the code and I'm not sure if I 
should remove the function.

regards,
Yiyang
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