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From: Anant Thazhemadam <anant.thazhemadam@gmail.com>
To: petkan@nucleusys.com, davem@davemloft.net, kuba@kernel.org
Cc: Anant Thazhemadam <anant.thazhemadam@gmail.com>,
	linux-usb@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-next@vger.kernel.org, sfr@canb.auug.org.au
Subject: [PATCH v2] net: usb: rtl8150: don't incorrectly assign random MAC addresses
Date: Sun, 11 Oct 2020 23:00:30 +0530
Message-ID: <20201011173030.141582-1-anant.thazhemadam@gmail.com> (raw)
In-Reply-To: <20201010064459.6563-1-anant.thazhemadam@gmail.com>

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: f45a4248ea4c ("net: usb: rtl8150: set random MAC address when set_ethernet_addr() fails")
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
---
Changes in v2:
        * Fixed the format of the Fixes tag
        * Modified the commit message to better describe the issue being 
          fixed

+CCing Stephen and linux-next, since the commit fixed isn't in the networking
tree, but is present in linux-next.

 drivers/net/usb/rtl8150.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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);
-- 
2.25.1


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-10  6:44 [PATCH] " Anant Thazhemadam
2020-10-10 16:59 ` Jakub Kicinski
2020-10-10 18:04   ` Anant Thazhemadam
2020-10-10 18:16     ` Jakub Kicinski
2020-10-10 18:44       ` Anant Thazhemadam
2020-10-10 19:20         ` Jakub Kicinski
2020-10-11 17:30 ` Anant Thazhemadam [this message]
2020-10-11 17:59   ` [PATCH v2] " Jakub Kicinski
2020-10-11 18:33     ` Joe Perches
2020-10-11 19:31       ` Petko Manolov
2020-10-11 20:14         ` Joe Perches
2020-10-11 22:14   ` Stephen Rothwell
2020-10-15 21:59     ` Stephen Rothwell
2020-10-15 22:24       ` Jakub Kicinski
2020-10-15 22:37         ` Jakub Kicinski
2020-10-18 19:54           ` Jakub Kicinski

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