From: Oliver Neukum <oneukum@suse.com>
To: Lukas Wunner <lukas@wunner.de>, Oliver Neukum <oneukum@suse.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Jann Horn <jannh@google.com>,
Oleksij Rempel <o.rempel@pengutronix.de>
Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org,
Andrew Lunn <andrew@lunn.ch>, Eric Dumazet <edumazet@google.com>,
Jacky Chou <jackychou@asix.com.tw>, Willy Tarreau <w@1wt.eu>,
Lino Sanfilippo <LinoSanfilippo@gmx.de>,
Philipp Rosenberger <p.rosenberger@kunbus.com>,
Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [PATCH] usbnet: Fix use-after-free on disconnect
Date: Wed, 13 Apr 2022 20:59:48 +0200 [thread overview]
Message-ID: <614e6498-3c3e-0104-591e-8ea296dfd887@suse.com> (raw)
In-Reply-To: <127121d9d933ebe3fc13f9f91cc33363d6a8a8ac.1649859147.git.lukas@wunner.de>
On 13.04.22 16:16, Lukas Wunner wrote:
> Jann Horn reports a use-after-free on disconnect of a USB Ethernet
> (ax88179_178a.c). Oleksij Rempel has witnessed the same issue with a
> different driver (ax88172a.c).
I see. Very good catch
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -469,6 +469,9 @@ static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
> */
> void usbnet_defer_kevent (struct usbnet *dev, int work)
> {
> + if (dev->intf->condition == USB_INTERFACE_UNBINDING)
> + return;
But, no, you cannot do this. This is a very blatant layering violation.
You cannot use states internal to usb core like that in a driver.
I see two options.
1. A dedicated flag in usbnet (then please with the correct smp barriers)
2. You introduce an API to usb core to query this.
Regards
Oliver
next prev parent reply other threads:[~2022-04-13 19:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 14:16 [PATCH] usbnet: Fix use-after-free on disconnect Lukas Wunner
2022-04-13 18:59 ` Oliver Neukum [this message]
2022-04-14 10:58 ` Lukas Wunner
2022-04-14 11:07 ` Greg Kroah-Hartman
2022-04-17 7:28 ` Lukas Wunner
2022-04-14 11:20 ` Oliver Neukum
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