Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33;
Date:   Tue, 26 Sep 2023 10:02:02 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc:     Alexander Aring <alex.aring@gmail.com>,
        Stefan Schmidt <stefan@datenfreihafen.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Harry Morris <harrymorris12@gmail.com>,
        linux-wpan@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [v2] ieee802154: ca8210: Fix a potential UAF in
 ca8210_probe
Message-ID: <20230926100202.011ab841@xps-13>
In-Reply-To: <20230926032244.11560-1-dinghao.liu@zju.edu.cn>
References: <20230926032244.11560-1-dinghao.liu@zju.edu.cn>
Organization: Bootlin
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hi Dinghao,

dinghao.liu@zju.edu.cn wrote on Tue, 26 Sep 2023 11:22:44 +0800:

> If of_clk_add_provider() fails in ca8210_register_ext_clock(),
> it calls clk_unregister() to release priv->clk and returns an
> error. However, the caller ca8210_probe() then calls ca8210_remove(),
> where priv->clk is freed again in ca8210_unregister_ext_clock(). In
> this case, a use-after-free may happen in the second time we call
> clk_unregister().
>=20
> Fix this by removing the first clk_unregister(). Also, priv->clk could
> be an error code on failure of clk_register_fixed_rate(). Use
> IS_ERR_OR_NULL to catch this case in ca8210_unregister_ext_clock().
>=20
> Fixes: ded845a781a5 ("ieee802154: Add CA8210 IEEE 802.15.4 device driver")

Missing Cc stable, this needs to be backported.

> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>=20
> Changelog:
>=20
> v2: -Remove the first clk_unregister() instead of nulling priv->clk.
> ---
>  drivers/net/ieee802154/ca8210.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>=20
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8=
210.c
> index aebb19f1b3a4..b35c6f59bd1a 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -2759,7 +2759,6 @@ static int ca8210_register_ext_clock(struct spi_dev=
ice *spi)
>  	}
>  	ret =3D of_clk_add_provider(np, of_clk_src_simple_get, priv->clk);
>  	if (ret) {
> -		clk_unregister(priv->clk);
>  		dev_crit(
>  			&spi->dev,
>  			"Failed to register external clock as clock provider\n"

I was hoping you would simplify this function a bit more.

> @@ -2780,7 +2779,7 @@ static void ca8210_unregister_ext_clock(struct spi_=
device *spi)
>  {
>  	struct ca8210_priv *priv =3D spi_get_drvdata(spi);
> =20
> -	if (!priv->clk)
> +	if (IS_ERR_OR_NULL(priv->clk))
>  		return
> =20
>  	of_clk_del_provider(spi->dev.of_node);

Alex, Stefan, who handles wpan and wpan/next this release?

Thanks,
Miqu=C3=A8l