linux-kernel - Re: [PATCH v2] ovl: Filter invalid inodes with missing lookup function

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Message-ID: <CAOQ4uxhOTYZdjuVajBV_-wrQnVOERUOz7UmJJvcDUkWpkXkDvw@mail.gmail.com>
Date: Wed, 20 Nov 2024 13:34:39 +0100
From: Amir Goldstein <amir73il@...il.com>
To: Vasiliy Kovalev <kovalev@...linux.org>
Cc: Miklos Szeredi <miklos@...redi.hu>, linux-unionfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ovl: Filter invalid inodes with missing lookup function

On Tue, Nov 19, 2024 at 4:58 PM Vasiliy Kovalev <kovalev@...linux.org> wrote:
>
> Add a check to the ovl_dentry_weird() function to prevent the
> processing of directory inodes that lack the lookup function.
> This is important because such inodes can cause errors in overlayfs
> when passed to the lowerstack.
>
> Reported-by: syzbot+a8c9d476508bd14a90e5@...kaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?extid=a8c9d476508bd14a90e5
> Suggested-by: Miklos Szeredi <miklos@...redi.hu>
> Signed-off-by: Vasiliy Kovalev <kovalev@...linux.org>
> Cc: <stable@...r.kernel.org>
> ---
>  fs/overlayfs/util.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
> index 3bb107471fb42..9aa7493b1e103 100644
> --- a/fs/overlayfs/util.c
> +++ b/fs/overlayfs/util.c
> @@ -202,6 +202,9 @@ void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
>
>  bool ovl_dentry_weird(struct dentry *dentry)
>  {
> +       if (!d_can_lookup(dentry) && !d_is_file(dentry) && !d_is_symlink(dentry))
> +               return true;
> +
>         return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
>                                   DCACHE_MANAGE_TRANSIT |
>                                   DCACHE_OP_HASH |
> --
> 2.33.8
>

Applied to overlayfs-next. Will send along with 6.13 PR

Thanks,
Amir.