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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Peilin Ye <peilin.ye@bytedance.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>,
        syzbot+dcd3e13cf4472f2e0ba1@syzkaller.appspotmail.com
Subject: [PATCH 4.19 21/25] usbnet: Fix memory leak in usbnet_disconnect()
Date:   Mon,  3 Oct 2022 09:12:24 +0200
Message-Id: <20221003070716.040690340@linuxfoundation.org>
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From: Peilin Ye <peilin.ye@bytedance.com>

[ Upstream commit a43206156263fbaf1f2b7f96257441f331e91bb7 ]

Currently usbnet_disconnect() unanchors and frees all deferred URBs
using usb_scuttle_anchored_urbs(), which does not free urb->context,
causing a memory leak as reported by syzbot.

Use a usb_get_from_anchor() while loop instead, similar to what we did
in commit 19cfe912c37b ("Bluetooth: btusb: Fix memory leak in
play_deferred").  Also free urb->sg.

Reported-and-tested-by: syzbot+dcd3e13cf4472f2e0ba1@syzkaller.appspotmail.com
Fixes: 69ee472f2706 ("usbnet & cdc-ether: Autosuspend for online devices")
Fixes: 638c5115a794 ("USBNET: support DMA SG")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Link: https://lore.kernel.org/r/20220923042551.2745-1-yepeilin.cs@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/usbnet.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 1316f5b0c0d7..2263a66f6314 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1596,6 +1596,7 @@ void usbnet_disconnect (struct usb_interface *intf)
 	struct usbnet		*dev;
 	struct usb_device	*xdev;
 	struct net_device	*net;
+	struct urb		*urb;
 
 	dev = usb_get_intfdata(intf);
 	usb_set_intfdata(intf, NULL);
@@ -1612,7 +1613,11 @@ void usbnet_disconnect (struct usb_interface *intf)
 	net = dev->net;
 	unregister_netdev (net);
 
-	usb_scuttle_anchored_urbs(&dev->deferred);
+	while ((urb = usb_get_from_anchor(&dev->deferred))) {
+		dev_kfree_skb(urb->context);
+		kfree(urb->sg);
+		usb_free_urb(urb);
+	}
 
 	if (dev->driver_info->unbind)
 		dev->driver_info->unbind (dev, intf);
-- 
2.35.1