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From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Chunfeng Yun <chunfeng.yun@mediatek.com>,
	linux-mediatek@lists.infradead.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Markus Elfring <Markus.Elfring@web.de>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] usb: mtu3: fix NULL pointer dereference
Date: Mon, 29 Jun 2020 14:00:34 +0800	[thread overview]
Message-ID: <1593410434-19406-2-git-send-email-chunfeng.yun@mediatek.com> (raw)
In-Reply-To: <1593410434-19406-1-git-send-email-chunfeng.yun@mediatek.com>

Some pointers are dereferenced before successful checks.

Reported-by: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
 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;
+
+	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;
 
+	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;
 
+	mep = to_mtu3_ep(ep);
 	mep->wedged = 1;
 
 	return usb_ep_set_halt(ep);
-- 
1.9.1
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  reply	other threads:[~2020-06-29  6:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29  6:00 [PATCH 1/2] usb: mtu3: disable USB2 LPM Chunfeng Yun
2020-06-29  6:00 ` Chunfeng Yun [this message]
2020-06-29  8:00   ` [PATCH 2/2] usb: mtu3: fix NULL pointer dereference Markus Elfring
2020-06-29  8:10     ` Greg Kroah-Hartman
2020-06-30  7:28     ` Chunfeng Yun
2020-06-29 16:19   ` Searching for initialisation of variables by function calls before null pointer checks Markus Elfring
2020-06-29  7:30 ` [PATCH 1/2] usb: mtu3: disable USB2 LPM Markus Elfring
2020-06-29  8:10   ` Greg Kroah-Hartman
2020-06-29  7:37 ` Peter Chen
2020-06-30  7:03   ` Chunfeng Yun
2020-06-29  8:15 ` Markus Elfring

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