linux-kernel - Re: [PATCH] media: Fix invalid link creation when source entity has 0 pads

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANiDSCsvEke31SAgXhs_sXEN7d6fXrwuhJFsi2mzESq1Jc8pxA@mail.gmail.com>
Date: Tue, 25 Mar 2025 09:56:43 +0100
From: Ricardo Ribalda <ribalda@...omium.org>
To: gshahrouzi@...il.com
Cc: laurent.pinchart@...asonboard.com, hdegoede@...hat.com, mchehab@...nel.org, 
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzbot+701fc9cc0cb44e2b0fe9@...kaller.appspotmail.com, 
	skhan@...uxfoundation.org, kernelmentees@...ts.linuxfoundation.org
Subject: Re: [PATCH] media: Fix invalid link creation when source entity has 0 pads

Hi Gabriel

On Tue, 25 Mar 2025 at 08:55, <gshahrouzi@...il.com> wrote:
>
> >From 307209d175be0145e36b9cf95944e2e62afeab11 Mon Sep 17 00:00:00 2001
> From: Gabriel Shahrouzi <gshahrouzi@...il.com>
> Date: Mon, 24 Mar 2025 19:45:55 -0400
> Subject: [PATCH] media: Fix invalid link creation when source entity has 0
>  pads
>
> This patch addresses the warning triggered in the media_create_pad_link()
> function, specifically related to the check WARN_ON(source_pad >=
> source->num_pads). The fix proposed adds an additional check to ensure that
> source->num_pads is non-zero before proceeding with the
> media_create_pad_link() function.
>
> Reported-by: syzbot+701fc9cc0cb44e2b0fe9@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=701fc9cc0cb44e2b0fe9
I cannot reach that URL
> Tested-by: syzbot+701fc9cc0cb44e2b0fe9@...kaller.appspotmail.com
> Fixes: a3fbc2e6bb05 ("media: mc-entity.c: use WARN_ON, validate link pads")
Shouldn't it be? :
Fixes: 4ffc2d89f38a ("[media] uvcvideo: Register subdevices for each entity")

> Signed-off-by: Gabriel Shahrouzi <gshahrouzi@...il.com>
> ---
>  drivers/media/usb/uvc/uvc_entity.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_entity.c b/drivers/media/usb/uvc/uvc_entity.c
> index cc68dd24eb42..5397ce76c218 100644
> --- a/drivers/media/usb/uvc/uvc_entity.c
> +++ b/drivers/media/usb/uvc/uvc_entity.c
> @@ -43,7 +43,7 @@ static int uvc_mc_create_links(struct uvc_video_chain *chain,
>                 source = (UVC_ENTITY_TYPE(remote) == UVC_TT_STREAMING)
>                        ? (remote->vdev ? &remote->vdev->entity : NULL)
>                        : &remote->subdev.entity;
> -               if (source == NULL)
> +               if (source == NULL || source->num_pads == 0)
Shouldn't source->num_pads be the same as remote->num_pads?

Are you sure that your kernel does not contain?
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/media/usb/uvc/uvc_entity.c?id=41ddb251c68ac75c101d3a50a68c4629c9055e4c

Regards!

>                         continue;
>
>                 remote_pad = remote->num_pads - 1;
> --
> 2.43.0
>


-- 
Ricardo Ribalda