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From:   Pavel Skripkin <paskripkin@gmail.com>
To:     wg@grandegger.com, mkl@pengutronix.de, davem@davemloft.net,
        kuba@kernel.org, mailhol.vincent@wanadoo.fr
Cc:     linux-can@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Pavel Skripkin <paskripkin@gmail.com>,
        syzbot+91adee8d9ebb9193d22d@syzkaller.appspotmail.com
Subject: [PATCH] drivers: net: fix memory leak in peak_usb_create_dev
Date:   Thu,  1 Apr 2021 16:27:52 +0300
Message-Id: <20210401132752.25358-1-paskripkin@gmail.com>
MIME-Version: 1.0
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syzbot reported memory leak in peak_usb.
The problem was in case of failure after calling
->dev_init()[2] in peak_usb_create_dev()[1]. The data
allocated int dev_init() wasn't freed, so simple
->dev_free() call fix this problem.

backtrace:
    [<0000000079d6542a>] kmalloc include/linux/slab.h:552 [inline]
    [<0000000079d6542a>] kzalloc include/linux/slab.h:682 [inline]
    [<0000000079d6542a>] pcan_usb_fd_init+0x156/0x210 drivers/net/can/usb/peak_usb/pcan_usb_fd.c:868   [2]
    [<00000000c09f9057>] peak_usb_create_dev drivers/net/can/usb/peak_usb/pcan_usb_core.c:851 [inline] [1]
    [<00000000c09f9057>] peak_usb_probe+0x389/0x490 drivers/net/can/usb/peak_usb/pcan_usb_core.c:949

Reported-by: syzbot+91adee8d9ebb9193d22d@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/net/can/usb/peak_usb/pcan_usb_core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index 573b11559d73..28e916a04047 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -857,7 +857,7 @@ static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
 	if (dev->adapter->dev_set_bus) {
 		err = dev->adapter->dev_set_bus(dev, 0);
 		if (err)
-			goto lbl_unregister_candev;
+			goto adap_dev_free;
 	}
 
 	/* get device number early */
@@ -869,6 +869,10 @@ static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
 
 	return 0;
 
+adap_dev_free:
+	if (dev->adapter->dev_free)
+		dev->adapter->dev_free(dev);
+
 lbl_unregister_candev:
 	unregister_candev(netdev);
 
-- 
2.30.2