From: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Date: Sun, 11 Oct 2020 17:30:30 +0000 (+0530)
Subject: net: usb: rtl8150: don't incorrectly assign random MAC addresses
X-Git-Tag: v5.15~2588^2~35
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=60f1626f0f866809de801724c3d180a9f322841e;p=mirror_ubuntu-kernels.git

net: usb: rtl8150: don't incorrectly assign random MAC addresses

In set_ethernet_addr(), if get_registers() succeeds, the ethernet address
that was read must be copied over. Otherwise, a random ethernet address
must be assigned.

get_registers() returns 0 if successful, and negative error number
otherwise. However, in set_ethernet_addr(), this return value is
incorrectly checked.

Since this return value will never be equal to sizeof(node_id), a
random MAC address will always be generated and assigned to the
device; even in cases when get_registers() is successful.

Correctly modifying the condition that checks if get_registers() was
successful or not fixes this problem, and copies the ethernet address
appropriately.

Fixes: b2a0f274e3f7 ("net: rtl8150: Use the new usb control message API.")
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Link: https://lore.kernel.org/r/20201011173030.141582-1-anant.thazhemadam@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
index f020401adf04..bf8a60533f3e 100644
--- a/drivers/net/usb/rtl8150.c
+++ b/drivers/net/usb/rtl8150.c
@@ -261,7 +261,7 @@ static void set_ethernet_addr(rtl8150_t *dev)
 
 	ret = get_registers(dev, IDR, sizeof(node_id), node_id);
 
-	if (ret == sizeof(node_id)) {
+	if (!ret) {
 		ether_addr_copy(dev->netdev->dev_addr, node_id);
 	} else {
 		eth_hw_addr_random(dev->netdev);