netdev - [PATCH net-next v3 1/2] usbnet: ipheth: fix risk of NULL pointer deallocation

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Date: Sat, 27 May 2023 15:03:08 +0200
From: Foster Snowhill <forst@....gy>
To: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Georgi Valkov <gvalkov@...il.com>,
	Simon Horman <simon.horman@...igine.com>,
	Jan Kiszka <jan.kiszka@...mens.com>,
	linux-usb@...r.kernel.org,
	netdev@...r.kernel.org
Subject: [PATCH net-next v3 1/2] usbnet: ipheth: fix risk of NULL pointer deallocation

From: Georgi Valkov <gvalkov@...il.com>

The cleanup precedure in ipheth_probe will attempt to free a
NULL pointer in dev->ctrl_buf if the memory allocation for
this buffer is not successful. While kfree ignores NULL pointers,
and the existing code is safe, it is a better design to rearrange
the goto labels and avoid this.

Signed-off-by: Georgi Valkov <gvalkov@...il.com>
Signed-off-by: Foster Snowhill <forst@....gy>
---
v3:
  - Reword commit msg to indicate design improvement rather than bugfix
  - Add missing signoff for Foster Snowhill
  No code changes
v2: https://lore.kernel.org/netdev/20230525194255.4516-1-forst@pen.gy/
  - Factor out goto label change from v1 into this separate patch
v1: n/a
  Part of https://lore.kernel.org/netdev/20230516210127.35841-1-forst@pen.gy/
---
 drivers/net/usb/ipheth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index 6a769df0b..8875a3d0e 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -510,8 +510,8 @@ static int ipheth_probe(struct usb_interface *intf,
 	ipheth_free_urbs(dev);
 err_alloc_urbs:
 err_get_macaddr:
-err_alloc_ctrl_buf:
 	kfree(dev->ctrl_buf);
+err_alloc_ctrl_buf:
 err_endpoints:
 	free_netdev(netdev);
 	return retval;
-- 
2.40.1