[PATCH] usbnet: ipheth: fix potential null pointer dereference in ipheth_carrier_set

[PATCH] usbnet: ipheth: fix potential null pointer dereference in ipheth_carrier_set

[Gustavo A. R. Silva]

_dev_ is being dereferenced before it is null checked, hence there
is a potential null pointer dereference.

Fix this by moving the pointer dereference after _dev_ has been null
checked.

Addresses-Coverity-ID: 1462020
Fixes: bb1b40c7cb86 ("usbnet: ipheth: prevent TX queue timeouts when device not ready")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/net/usb/ipheth.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index ca71f6c..7275761 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -291,12 +291,15 @@ static void ipheth_sndbulk_callback(struct urb *urb)
 
 static int ipheth_carrier_set(struct ipheth_device *dev)
 {
-	struct usb_device *udev = dev->udev;
+	struct usb_device *udev;
 	int retval;
+
 	if (!dev)
 		return 0;
 	if (!dev->confirmed_pairing)
 		return 0;
+
+	udev = dev->udev;
 	retval = usb_control_msg(udev,
 			usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
 			IPHETH_CMD_CARRIER_CHECK, /* request */
-- 
2.7.4

Re: [PATCH] usbnet: ipheth: fix potential null pointer dereference in ipheth_carrier_set

[David Miller]

From: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Date: Fri, 17 Nov 2017 14:02:09 -0600

> _dev_ is being dereferenced before it is null checked, hence there
> is a potential null pointer dereference.
> 
> Fix this by moving the pointer dereference after _dev_ has been null
> checked.
> 
> Addresses-Coverity-ID: 1462020
> Fixes: bb1b40c7cb86 ("usbnet: ipheth: prevent TX queue timeouts when device not ready")
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

Applied, thanks.