From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Bin Liu <b-liu@ti.com>
Cc: linux-usb@vger.kernel.org
Subject: Re: [PATCH 2/2] usb: musb: Fix a possible null-pointer dereference in musb_handle_intr_connect()
Date: Wed, 11 Dec 2019 17:10:17 +0800 [thread overview]
Message-ID: <dc1cbf76-a2c4-a861-0847-d3434b843fee@gmail.com> (raw)
In-Reply-To: <20191211080910.GA426347@kroah.com>
On 2019/12/11 16:09, Greg Kroah-Hartman wrote:
> On Tue, Dec 10, 2019 at 10:54:54AM -0600, Bin Liu wrote:
>> From: Jia-Ju Bai <baijiaju1990@gmail.com>
>>
>> In musb_handle_intr_connect(), there is an if statement on line 783 to
>> check whether musb->hcd is NULL:
>> if (musb->hcd)
>>
>> When musb->hcd is NULL, it is used on line 797:
>> musb_host_poke_root_hub(musb);
>> if (musb->hcd->status_urb)
>>
>> Thus, a possible null-pointer dereference may occur.
> Maybe, if musb->hcd really ever could be NULL.
>
> In looking at the code, I don't see where that could happen, do you?
> Why is that check there in the first place?
>
> What sets musb->hcd to NULL in the first place?
In fact, my static analysis tool identifies an if check about musb->hcd,
so it infers that musb->hcd could be NULL here.
But it does not try to find any explicit place that set musb->hcd to NULL.
If musb->hcd is never NULL here, we can just delete the related if check.
Best wishes,
Jia-Ju Bai
next prev parent reply other threads:[~2019-12-11 9:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 16:54 [PATCH 0/2] musb fixes for v5.5-rc2 Bin Liu
2019-12-10 16:54 ` [PATCH 1/2] usb: musb: sunxi: propagate devicetree node to glue pdev Bin Liu
2019-12-11 8:05 ` Greg Kroah-Hartman
2019-12-11 8:49 ` Johan Hovold
2019-12-11 8:51 ` Greg Kroah-Hartman
2019-12-11 8:53 ` Johan Hovold
2019-12-10 16:54 ` [PATCH 2/2] usb: musb: Fix a possible null-pointer dereference in musb_handle_intr_connect() Bin Liu
2019-12-11 8:09 ` Greg Kroah-Hartman
2019-12-11 9:10 ` Jia-Ju Bai [this message]
2019-12-11 9:20 ` Greg Kroah-Hartman
2019-12-17 8:26 ` Jia-Ju Bai
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