linux-kernel - Re: [PATCH] isdn: mISDN: Fix potential NULL pointer dereference of kzalloc

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Message-ID: <0337960b-55ea-e036-0e10-66cd71d21b85@umn.edu>
Date:   Sat, 2 Mar 2019 15:39:00 -0600
From:   Kangjie Lu <kjlu@....edu>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Aditya Pakki <pakki001@....edu>
Cc:     Karsten Keil <isdn@...ux-pingi.de>,
        "David S. Miller" <davem@...emloft.net>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] isdn: mISDN: Fix potential NULL pointer dereference of
 kzalloc


On 3/2/19 3:26 PM, Gustavo A. R. Silva wrote:
>
> On 3/2/19 3:20 PM, Aditya Pakki wrote:
>> Allocating memory via kzalloc for phi may fail and causes a
>> NULL pointer dereference. This patch avoids such a scenario.
>>
> Was this detected by Coccinelle?


It was detected by an LLVM-based static analyzer we recently developed.


>
> If so, please mention it in the commit log.
>
> Thanks
> --
> Gustavo
>
>> Signed-off-by: Aditya Pakki <pakki001@....edu>
>> ---
>>   drivers/isdn/hardware/mISDN/hfcsusb.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
>> index 124ff530da82..26e3182bbca8 100644
>> --- a/drivers/isdn/hardware/mISDN/hfcsusb.c
>> +++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
>> @@ -263,6 +263,9 @@ hfcsusb_ph_info(struct hfcsusb *hw)
>>   	int i;
>>   
>>   	phi = kzalloc(struct_size(phi, bch, dch->dev.nrbchan), GFP_ATOMIC);
>> +	if (!phi)
>> +		return;
>> +
>>   	phi->dch.ch.protocol = hw->protocol;
>>   	phi->dch.ch.Flags = dch->Flags;
>>   	phi->dch.state = dch->state;
>>