[PATCH AUTOSEL for 4.4 34/35] usb: gadget: don't dereference g until after it has been null checked

Sasha Levin
2018-01-24T04:20:06Z

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

[ Upstream commit b2fc059fa549fe6881d4c1f8d698b0f50bcd16ec ]

Avoid dereferencing pointer g until after g has been sanity null checked;
move the assignment of cdev much later when it is required into a more
local scope.

Detected by CoverityScan, CID#1222135 ("Dereference before null check")

Fixes: b785ea7ce662 ("usb: gadget: composite: fix ep->maxburst initialization")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/usb/gadget/composite.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index d186d0282a38..f70dd3dd4393 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -104,7 +104,6 @@ int config_ep_by_speed(struct usb_gadget *g,
struct usb_function *f,
struct usb_ep *_ep)
{
- struct usb_composite_dev *cdev = get_gadget_data(g);
struct usb_endpoint_descriptor *chosen_desc = NULL;
struct usb_descriptor_header **speed_desc = NULL;

@@ -176,8 +175,12 @@ ep_found:
_ep->maxburst = comp_desc->bMaxBurst + 1;
break;
default:
- if (comp_desc->bMaxBurst != 0)
+ if (comp_desc->bMaxBurst != 0) {
+ struct usb_composite_dev *cdev;
+
+ cdev = get_gadget_data(g);
ERROR(cdev, "ep0 bMaxBurst must be 0\n");
+ }
_ep->maxburst = 1;
break;
}
--
2.11.0