netdev - [PATCH 1/6] can: esd_usb: Fix possible calls to kfree() with NULL

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Message-Id: <20250811210611.3233202-2-stefan.maetje@esd.eu>
Date: Mon, 11 Aug 2025 23:06:06 +0200
From: Stefan Mätje <stefan.maetje@....eu>
To: Marc Kleine-Budde <mkl@...gutronix.de>,
	Vincent Mailhol <mailhol.vincent@...adoo.fr>,
	Frank Jungclaus <frank.jungclaus@....eu>,
	linux-can@...r.kernel.org,
	socketcan@....eu
Cc: Simon Horman <horms@...nel.org>,
	Olivier Sobrie <olivier@...rie.be>,
	Oliver Hartkopp <socketcan@...tkopp.net>,
	netdev@...r.kernel.org
Subject: [PATCH 1/6] can: esd_usb: Fix possible calls to kfree() with NULL

In esd_usb_start() kfree() is called with the msg variable even if the
allocation of *msg failed.

Move the kfree() call to a line before the allocation error exit label
out: and adjust the exits for other errors to the new free_msg: label
just before kfree().

In esd_usb_probe() add free_dev: label and skip calling kfree() if
allocation of *msg failed.

Fixes: fae37f81fdf3 ( "net: can: esd_usb2: Do not do dma on the stack" )
Signed-off-by: Stefan Mätje <stefan.maetje@....eu>
---
 drivers/net/can/usb/esd_usb.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 27a3818885c2..05ed664cf59d 100644
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -3,7 +3,7 @@
  * CAN driver for esd electronics gmbh CAN-USB/2, CAN-USB/3 and CAN-USB/Micro
  *
  * Copyright (C) 2010-2012 esd electronic system design gmbh, Matthias Fuchs <socketcan@....eu>
- * Copyright (C) 2022-2024 esd electronics gmbh, Frank Jungclaus <frank.jungclaus@....eu>
+ * Copyright (C) 2022-2025 esd electronics gmbh, Frank Jungclaus <frank.jungclaus@....eu>
  */
 
 #include <linux/can.h>
@@ -746,21 +746,22 @@ static int esd_usb_start(struct esd_usb_net_priv *priv)
 
 	err = esd_usb_send_msg(dev, msg);
 	if (err)
-		goto out;
+		goto free_msg;
 
 	err = esd_usb_setup_rx_urbs(dev);
 	if (err)
-		goto out;
+		goto free_msg;
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
+free_msg:
+	kfree(msg);
 out:
 	if (err == -ENODEV)
 		netif_device_detach(netdev);
 	if (err)
 		netdev_err(netdev, "couldn't start device: %d\n", err);
 
-	kfree(msg);
 	return err;
 }
 
@@ -1279,7 +1280,7 @@ static int esd_usb_probe(struct usb_interface *intf,
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev) {
 		err = -ENOMEM;
-		goto done;
+		goto bail;
 	}
 
 	dev->udev = interface_to_usbdev(intf);
@@ -1291,7 +1292,7 @@ static int esd_usb_probe(struct usb_interface *intf,
 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
 	if (!msg) {
 		err = -ENOMEM;
-		goto free_msg;
+		goto free_dev;
 	}
 
 	/* query number of CAN interfaces (nets) */
@@ -1334,9 +1335,10 @@ static int esd_usb_probe(struct usb_interface *intf,
 
 free_msg:
 	kfree(msg);
+free_dev:
 	if (err)
 		kfree(dev);
-done:
+bail:
 	return err;
 }
 
-- 
2.34.1