linux-kernel - Re: [PATCH] media: renesas: rzg2l-cru: Fix possible ERR_PTR dereference in rzg2l_cru_get_virtual

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Message-ID: <20251227130514.GA21104@pendragon.ideasonboard.com>
Date: Sat, 27 Dec 2025 15:05:14 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Alper Ak <alperyasinak1@...il.com>
Cc: mchehab@...nel.org, hverkuil+cisco@...nel.org,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
	Tommaso Merciai <tommaso.merciai.xr@...renesas.com>,
	Daniel Scally <dan.scally+renesas@...asonboard.com>,
	Biju Das <biju.das.jz@...renesas.com>,
	Jacopo Mondi <jacopo.mondi@...asonboard.com>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: renesas: rzg2l-cru: Fix possible ERR_PTR
 dereference in rzg2l_cru_get_virtual_channel()

On Sat, Dec 27, 2025 at 03:19:44PM +0300, Alper Ak wrote:
> media_pad_remote_pad_unique() can return ERR_PTR(-ENOTUNIQ) or
> ERR_PTR(-ENOLINK) on error situation.
> 
> The current code dereferences remote_pad without checking for
> these error cases, which could lead to invalid memory access.

What makes you think this can happen ?

> Add IS_ERR() check before dereferencing the pointer.
> 
> Fixes: d7d72dae81d5 ("media: rzg2l-cru: Retrieve virtual channel information")
> Signed-off-by: Alper Ak <alperyasinak1@...il.com>
> ---
>  drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> index 162e2ace6931..bf7d96841c78 100644
> --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> @@ -411,6 +411,9 @@ static int rzg2l_cru_get_virtual_channel(struct rzg2l_cru_dev *cru)
>  	int ret;
>  
>  	remote_pad = media_pad_remote_pad_unique(&cru->ip.pads[RZG2L_CRU_IP_SINK]);
> +	if (IS_ERR(remote_pad))
> +		return PTR_ERR(remote_pad);
> +
>  	ret = v4l2_subdev_call(cru->ip.remote, pad, get_frame_desc, remote_pad->index, &fd);
>  	if (ret < 0 && ret != -ENOIOCTLCMD) {
>  		dev_err(cru->dev, "get_frame_desc failed on IP remote subdev\n");

-- 
Regards,

Laurent Pinchart