Re: [PATCH] usb: isp1760: fix null dereference if kzalloc returns null

From: Colin Ian King
Date: Sun May 31 2015 - 18:43:50 EST


On 31/05/15 23:15, Sergei Shtylyov wrote:
> Hello.
>
> On 06/01/2015 01:00 AM, Colin King wrote:
>
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
>> If kzalloc returns null then isp1760_ep_alloc_request performs
>> a null pointer deference on req.
>
> Dereference, not "deference".

Shall I send v2 for this stupid typo then?

> No, it doesn't. It calculates the address of the
> 'isp1760_request::req' instead, there's no dereference per se. I suppose
> this is a first member of the structure, so this function should work
> correctly in any case.

Well, for now it's the first member, but can we assume that will apply
forever? As it stands, other *_alloc_request() functions in all the
other usb drivers check for the NULL, so this fix just aligns the code
with all of these other drivers.


>
>> Check for null to avoid this.
>
>> Detected with smatch static analysis:
>>
>> drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
>> error: potential null dereference 'req'. (kzalloc returns null)
>
> Well, the change won't hurt anyway, makes things clearer.
>
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> WBR, Sergei
>

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