[PATCH AUTOSEL 4.14 08/11] net: usb: rtl8150: set random MAC address when set_ethernet_addr() fails

Sasha Levin
2020-10-12T19:06:04Z

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

[ Upstream commit f45a4248ea4cc13ed50618ff066849f9587226b2 ]

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+abbc768b560c84d92fd3@syzkaller.appspotmail.com
Tested-by: syzbot+abbc768b560c84d92fd3@syzkaller.appspotmail.com
Acked-by: Petko Manolov <petkan@nucleusys.com>
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/rtl8150.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
index 48ba80a8ca5ce..3f4fc78498e03 100644
--- a/drivers/net/usb/rtl8150.c
+++ b/drivers/net/usb/rtl8150.c
@@ -277,12 +277,20 @@ static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 reg)
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;
+
+ ret = get_registers(dev, IDR, sizeof(node_id), node_id);

- get_registers(dev, IDR, sizeof(node_id), node_id);
- memcpy(dev->netdev->dev_addr, node_id, sizeof(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)
--
2.25.1