From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Markus Elfring <Markus.Elfring@web.de>,
linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [V2 PATCH] usb: mtu3: fix NULL pointer dereference
Date: Wed, 1 Jul 2020 13:58:21 +0200 [thread overview]
Message-ID: <20200701115821.GA2184169@kroah.com> (raw)
In-Reply-To: <1593502942-24455-1-git-send-email-chunfeng.yun@mediatek.com>
On Tue, Jun 30, 2020 at 03:42:22PM +0800, Chunfeng Yun wrote:
> Some pointers are dereferenced before successful checks.
>
> Reported-by: Markus Elfring <Markus.Elfring@web.de>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> ---
> v2: nothing changed, but abandon another patch
> ---
> drivers/usb/mtu3/mtu3_gadget.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/mtu3/mtu3_gadget.c b/drivers/usb/mtu3/mtu3_gadget.c
> index f93732e..1689ca8 100644
> --- a/drivers/usb/mtu3/mtu3_gadget.c
> +++ b/drivers/usb/mtu3/mtu3_gadget.c
> @@ -332,14 +332,21 @@ static int mtu3_gadget_queue(struct usb_ep *ep,
>
> static int mtu3_gadget_dequeue(struct usb_ep *ep, struct usb_request *req)
> {
> - struct mtu3_ep *mep = to_mtu3_ep(ep);
> - struct mtu3_request *mreq = to_mtu3_request(req);
> + struct mtu3_ep *mep;
> + struct mtu3_request *mreq;
> struct mtu3_request *r;
> + struct mtu3 *mtu;
> unsigned long flags;
> int ret = 0;
> - struct mtu3 *mtu = mep->mtu;
>
> - if (!ep || !req || mreq->mep != mep)
> + if (!ep || !req)
> + return -EINVAL;
How will either of those ever be NULL? The kernel will not call this
function with either of them being NULL, right?
> +
> + mep = to_mtu3_ep(ep);
> + mtu = mep->mtu;
> +
> + mreq = to_mtu3_request(req);
> + if (mreq->mep != mep)
> return -EINVAL;
>
> dev_dbg(mtu->dev, "%s : req=%p\n", __func__, req);
> @@ -373,8 +380,8 @@ static int mtu3_gadget_dequeue(struct usb_ep *ep, struct usb_request *req)
> */
> static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int value)
> {
> - struct mtu3_ep *mep = to_mtu3_ep(ep);
> - struct mtu3 *mtu = mep->mtu;
> + struct mtu3_ep *mep;
> + struct mtu3 *mtu;
> struct mtu3_request *mreq;
> unsigned long flags;
> int ret = 0;
> @@ -382,6 +389,9 @@ static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int value)
> if (!ep)
> return -EINVAL;
Same here, how can that ever happen?
>
> + mep = to_mtu3_ep(ep);
> + mtu = mep->mtu;
> +
> dev_dbg(mtu->dev, "%s : %s...", __func__, ep->name);
>
> spin_lock_irqsave(&mtu->lock, flags);
> @@ -422,11 +432,12 @@ static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int value)
> /* Sets the halt feature with the clear requests ignored */
> static int mtu3_gadget_ep_set_wedge(struct usb_ep *ep)
> {
> - struct mtu3_ep *mep = to_mtu3_ep(ep);
> + struct mtu3_ep *mep;
>
> if (!ep)
> return -EINVAL;
Again, same here.
thanks,
greg k-h
next prev parent reply other threads:[~2020-07-01 11:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 7:42 [V2 PATCH] usb: mtu3: fix NULL pointer dereference Chunfeng Yun
2020-06-30 10:47 ` [PATCH v2] usb: mtu3: Fix NULL pointer dereferences Markus Elfring
2020-07-01 11:58 ` Greg Kroah-Hartman [this message]
2020-07-02 2:52 ` [V2 PATCH] usb: mtu3: fix NULL pointer dereference Chunfeng Yun
2020-07-09 6:42 ` Felipe Balbi
2020-07-09 6:40 ` Felipe Balbi
2020-07-09 7:05 ` Chunfeng Yun
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