Re: [PATCH -next] mISDN: hfcsusb: Fix potential NULL pointer dereference

[YueHaibing]

On 2019/1/31 2:10, David Miller wrote:
> From: YueHaibing <yuehaibing@xxxxxxxxxx>
> Date: Wed, 30 Jan 2019 18:19:02 +0800
> 
>> There is a potential NULL pointer dereference in case
>> kzalloc() fails and returns NULL.
>>
>> Fixes: 69f52adb2d53 ("mISDN: Add HFC USB driver")
>> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
>> ---
>>  drivers/isdn/hardware/mISDN/hfcsusb.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
>> index 124ff53..5660d5a 100644
>> --- a/drivers/isdn/hardware/mISDN/hfcsusb.c
>> +++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
>> @@ -263,6 +263,8 @@ hfcsusb_ph_info(struct hfcsusb *hw)
>>  	int i;
>>  
>>  	phi = kzalloc(struct_size(phi, bch, dch->dev.nrbchan), GFP_ATOMIC);
>> +	if (!phi)
>> +		return;
> 
> If we fail with an error and do not perform the operation we were requested to
> make, we must return an error to the caller, and the caller must do something
> reasonable with that error (perhaps return it to it's caller) and so on and
> so forth.


hfcsusb_ph_info alloced the 'phi'ïthen use it _alloc_mISDN_skb in _queue_data.
while _alloc_mISDN_skb fails, it also just return without err handling,then kfree(phi).
It seems that all the caller of hfcsusb_ph_info doesn't care the return value.

> 
> .
>