[PATCH AUTOSEL 4.14 075/108] usb: gadget: lpc32xx_udc: don't dereference ep pointer before null check

Sasha Levin
2020-06-18T01:49:48Z

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit eafa80041645cd7604c4357b1a0cd4a3c81f2227 ]

Currently pointer ep is being dereferenced before it is null checked
leading to a null pointer dereference issue. Fix this by only assigning
pointer udc once ep is known to be not null. Also remove a debug
message that requires a valid udc which may not be possible at that
point.

Addresses-Coverity: ("Dereference before null check")
Fixes: 24a28e428351 ("USB: gadget driver for LPC32xx")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/gadget/udc/lpc32xx_udc.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/lpc32xx_udc.c b/drivers/usb/gadget/udc/lpc32xx_udc.c
index ac2aa04ca657..710793161795 100644
--- a/drivers/usb/gadget/udc/lpc32xx_udc.c
+++ b/drivers/usb/gadget/udc/lpc32xx_udc.c
@@ -1615,17 +1615,17 @@ static int lpc32xx_ep_enable(struct usb_ep *_ep,
const struct usb_endpoint_descriptor *desc)
{
struct lpc32xx_ep *ep = container_of(_ep, struct lpc32xx_ep, ep);
- struct lpc32xx_udc *udc = ep->udc;
+ struct lpc32xx_udc *udc;
u16 maxpacket;
u32 tmp;
unsigned long flags;

/* Verify EP data */
if ((!_ep) || (!ep) || (!desc) ||
- (desc->bDescriptorType != USB_DT_ENDPOINT)) {
- dev_dbg(udc->dev, "bad ep or descriptor\n");
+ (desc->bDescriptorType != USB_DT_ENDPOINT))
return -EINVAL;
- }
+
+ udc = ep->udc;
maxpacket = usb_endpoint_maxp(desc);
if ((maxpacket == 0) || (maxpacket > ep->maxpacket)) {
dev_dbg(udc->dev, "bad ep descriptor's packet size\n");
@@ -1873,7 +1873,7 @@ static int lpc32xx_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
static int lpc32xx_ep_set_halt(struct usb_ep *_ep, int value)
{
struct lpc32xx_ep *ep = container_of(_ep, struct lpc32xx_ep, ep);
- struct lpc32xx_udc *udc = ep->udc;
+ struct lpc32xx_udc *udc;
unsigned long flags;

if ((!ep) || (ep->hwep_num <= 1))
@@ -1883,6 +1883,7 @@ static int lpc32xx_ep_set_halt(struct usb_ep *_ep, int value)
if (ep->is_in)
return -EAGAIN;

+ udc = ep->udc;
spin_lock_irqsave(&udc->lock, flags);

if (value == 1) {
--
2.25.1