[V2 PATCH] usb: mtu3: fix NULL pointer dereference

Chunfeng Yun
2020-06-30T07:43:09Z

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;
+
+ 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