[PATCH v2 -next] usb: gadget: dereference before null check

Sebin Sebastian
2022-06-30T04:48:40Z

Fix coverity warning dereferencing before null check. _ep and desc is
dereferenced on all paths until the check for null. Move the
initializations after the check for null.
Coverity issue: 1518209

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sebin Sebastian <mailmesebin00@gmail.com>
---
Changes since v1: Fix the build errors and warnings due to first patch.
Fix the undeclared 'ep' and 'maxpacket' error. Fix the ISO C90 warning.

drivers/usb/gadget/udc/aspeed_udc.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/udc/aspeed_udc.c b/drivers/usb/gadget/udc/aspeed_udc.c
index d75a4e070bf7..a43cf8dde2a8 100644
--- a/drivers/usb/gadget/udc/aspeed_udc.c
+++ b/drivers/usb/gadget/udc/aspeed_udc.c
@@ -341,26 +341,33 @@ static void ast_udc_stop_activity(struct ast_udc_dev *udc)
static int ast_udc_ep_enable(struct usb_ep *_ep,
const struct usb_endpoint_descriptor *desc)
{
- u16 maxpacket = usb_endpoint_maxp(desc);
- struct ast_udc_ep *ep = to_ast_ep(_ep);
- struct ast_udc_dev *udc = ep->udc;
- u8 epnum = usb_endpoint_num(desc);
unsigned long flags;
u32 ep_conf = 0;
u8 dir_in;
u8 type;
+ u16 maxpacket;
+ struct ast_udc_ep *ep;
+ struct ast_udc_dev *udc;
+ u8 epnum;

- if (!_ep || !ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT ||
- maxpacket == 0 || maxpacket > ep->ep.maxpacket) {
+ if (!_ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
EP_DBG(ep, "Failed, invalid EP enable param\n");
return -EINVAL;
}
-
if (!udc->driver) {
EP_DBG(ep, "bogus device state\n");
return -ESHUTDOWN;
}

+ maxpacket = usb_endpoint_maxp(desc);
+ ep = to_ast_ep(_ep);
+ udc = ep->udc;
+ epnum = usb_endpoint_num(desc);
+ if (maxpacket == 0 || maxpacket > ep->ep.maxpacket) {
+ EP_DBG(ep, "Failed, invalid EP enable param\n");
+ return -EINVAL;
+ }
+
EP_DBG(ep, "maxpacket:0x%x\n", maxpacket);

spin_lock_irqsave(&udc->lock, flags);
--
2.34.1