net: usb: asix: Fix crash on skb alloc failure

If asix_rx_fixup_internal() fails to allocate rx->ax_skb, it will return
but not clear rx->size. rx points to driver private data. A later call
assumes that nonzero size means ax_skb was allocated and passes a null
ax_skb to skb_put. Changed allocation failure return to clear size first.

Found testing board with AX88772B devices.

Signed-off-by: David B. Robins <linux@davidrobins.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 75d6f26..079069a 100644 (file)
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -91,8 +91,10 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb,
                        }
                        rx->ax_skb = netdev_alloc_skb_ip_align(dev->net,
                                                               rx->size);
-                       if (!rx->ax_skb)
+                       if (!rx->ax_skb) {
+                               rx->size = 0;
                                return 0;
+                       }
                }
 
                if (rx->size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) {