[PATCH] usbnet: dereference after null check in usbnet_start_xmit() and __usbnet_read_cmd()

[Vivek Kumar Bhagat <vivek.bhagat@samsung.com>]

usbnet_start_xmit() - If info->tx_fixup is not defined by class driver,
NULL check does not happen for skb pointer and leads to NULL dereference.
__usbnet_read_cmd() - if data pointer is passed as NULL, memcpy will
dereference NULL pointer.

Signed-off-by: Vivek Kumar Bhagat <vivek.bhagat@samsung.com>
---
 drivers/net/usb/usbnet.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 3c86b10..ec4d224 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1294,6 +1294,8 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
 
 	if (skb)
 		skb_tx_timestamp(skb);
+	else
+		goto drop;
 
 	// some devices want funky USB-level framing, for
 	// win32 driver (usually) and/or hardware quirks
@@ -1906,7 +1908,8 @@ static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 		buf = kmalloc(size, GFP_KERNEL);
 		if (!buf)
 			goto out;
-	}
+	} else
+		goto out;
 
 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
 			      cmd, reqtype, value, index, buf, size,
-- 
1.7.9.5