Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Peter Chen <peter.chen@nxp.com>
To:     Wen Yang <wenyang@linux.alibaba.com>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: roles: fix a potential use after free
Thread-Topic: [PATCH] usb: roles: fix a potential use after free
Thread-Index: AQHVotK+QWYpBR3K1EiRCSfQT+CjR6ebobIA
Date:   Mon, 25 Nov 2019 09:35:30 +0000
Message-ID: <20191125093528.GC20079@b29397-desktop>
References: <20191124142236.25671-1-wenyang@linux.alibaba.com>
In-Reply-To: <20191124142236.25671-1-wenyang@linux.alibaba.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: nxp.com does not designate
 permitted sender hosts)
Content-Type: text/plain; charset="us-ascii"
Content-ID: <48D55C999BDD25479D8FBB074CFBCF06@eurprd04.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: fe38cf7e-c571-404e-b69c-08d7718ad020
X-MS-Exchange-CrossTenant-originalarrivaltime: 25 Nov 2019 09:35:30.6935
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: g0NXRlrnuOqRC397xLtDm7HQsle0knmiJts0sEXS4jkV06OYtub4HQfRHqvvPq6PlQ1nXV54Mjxaa5LdGjVZUA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR04MB6063
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 19-11-24 22:22:36, Wen Yang wrote:
> Free the sw structure only after we are done using it.
> This patch just moves the put_device() down a bit to avoid the
> use after free.
>=20
> Fixes: 5c54fcac9a9d ("usb: roles: Take care of driver module reference co=
unting")
> Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: linux-usb@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/usb/roles/class.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index 8273126..63a00ff 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -169,8 +169,8 @@ struct usb_role_switch *fwnode_usb_role_switch_get(st=
ruct fwnode_handle *fwnode)
>  void usb_role_switch_put(struct usb_role_switch *sw)
>  {
>  	if (!IS_ERR_OR_NULL(sw)) {
> -		put_device(&sw->dev);
>  		module_put(sw->dev.parent->driver->owner);
> +		put_device(&sw->dev);
>  	}
>  }
>  EXPORT_SYMBOL_GPL(usb_role_switch_put);
> --=20
> 1.8.3.1
>=20

Reviewed-by: Peter Chen <peter.chen@nxp.com>

--=20

Thanks,
Peter Chen=