From: Anant Thazhemadam <anant.thazhema...@gmail.com>

commit f45a4248ea4cc13ed50618ff066849f9587226b2 upstream.

When get_registers() fails in set_ethernet_addr(),the uninitialized
value of node_id gets copied over as the address.
So, check the return value of get_registers().

If get_registers() executed successfully (i.e., it returns
sizeof(node_id)), copy over the MAC address using ether_addr_copy()
(instead of using memcpy()).

Else, if get_registers() failed instead, a randomly generated MAC
address is set as the MAC address instead.

Reported-by: syzbot+abbc768b560c84d92...@syzkaller.appspotmail.com
Tested-by: syzbot+abbc768b560c84d92...@syzkaller.appspotmail.com
Acked-by: Petko Manolov <pet...@nucleusys.com>
Signed-off-by: Anant Thazhemadam <anant.thazhema...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/net/usb/rtl8150.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

--- a/drivers/net/usb/rtl8150.c
+++ b/drivers/net/usb/rtl8150.c
@@ -274,12 +274,20 @@ static int write_mii_word(rtl8150_t * de
                return 1;
 }
 
-static inline void set_ethernet_addr(rtl8150_t * dev)
+static void set_ethernet_addr(rtl8150_t *dev)
 {
-       u8 node_id[6];
+       u8 node_id[ETH_ALEN];
+       int ret;
 
-       get_registers(dev, IDR, sizeof(node_id), node_id);
-       memcpy(dev->netdev->dev_addr, node_id, sizeof(node_id));
+       ret = get_registers(dev, IDR, sizeof(node_id), node_id);
+
+       if (ret == sizeof(node_id)) {
+               ether_addr_copy(dev->netdev->dev_addr, node_id);
+       } else {
+               eth_hw_addr_random(dev->netdev);
+               netdev_notice(dev->netdev, "Assigned a random MAC address: 
%pM\n",
+                             dev->netdev->dev_addr);
+       }
 }
 
 static int rtl8150_set_mac_address(struct net_device *netdev, void *p)


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