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References: <20231008032908.11448-1-gehao@kylinos.cn>
In-Reply-To: <20231008032908.11448-1-gehao@kylinos.cn>
From:   Daniel Baluta <daniel.baluta@gmail.com>
Date:   Mon, 9 Oct 2023 14:07:33 +0300
Message-ID: <CAEnQRZBKkFxgpxJVcnmFQe33abQ-36ZXL_GgNgE3jVwH5+dEJQ@mail.gmail.com>
Subject: Re: [PATCH] firmware/imx-dsp: Fix use_after_free in imx_dsp_setup_channels()
To:     Hao Ge <gehao@kylinos.cn>
Cc:     shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
        festevam@gmail.com, linux-imx@nxp.com,
        christophe.jaillet@wanadoo.fr, robh@kernel.org, treding@nvidia.com,
        daniel.baluta@nxp.com, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, gehao618@163.com
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On Sun, Oct 8, 2023 at 6:30=E2=80=AFAM Hao Ge <gehao@kylinos.cn> wrote:
>
> dsp_chan->name and chan_name points to same block of memory,
> because dev_err still needs to be used it,so we need free
> it's memory after use to avoid use_after_free.
>
> Fixes: e527adfb9b7d ("firmware: imx-dsp: Fix an error handling path in im=
x_dsp_setup_channels()")
> Signed-off-by: Hao Ge <gehao@kylinos.cn>

Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>

> ---
>  drivers/firmware/imx/imx-dsp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/imx/imx-dsp.c b/drivers/firmware/imx/imx-ds=
p.c
> index 508eab346fc6..a48a58e0c61f 100644
> --- a/drivers/firmware/imx/imx-dsp.c
> +++ b/drivers/firmware/imx/imx-dsp.c
> @@ -114,11 +114,11 @@ static int imx_dsp_setup_channels(struct imx_dsp_ip=
c *dsp_ipc)
>                 dsp_chan->idx =3D i % 2;
>                 dsp_chan->ch =3D mbox_request_channel_byname(cl, chan_nam=
e);
>                 if (IS_ERR(dsp_chan->ch)) {
> -                       kfree(dsp_chan->name);
>                         ret =3D PTR_ERR(dsp_chan->ch);
>                         if (ret !=3D -EPROBE_DEFER)
>                                 dev_err(dev, "Failed to request mbox chan=
 %s ret %d\n",
>                                         chan_name, ret);
> +                       kfree(dsp_chan->name);
>                         goto out;
>                 }
>
> --
> 2.25.1
>