linux-kernel - Re: [syzbot] WARNING in internal_create

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: <20210812061839.GA26497@lst.de>
Date:   Thu, 12 Aug 2021 08:18:39 +0200
From:   Christoph Hellwig <hch@....de>
To:     Pavel Skripkin <paskripkin@...il.com>
Cc:     Christoph Hellwig <hch@....de>, Hillf Danton <hdanton@...a.com>,
        syzbot <syzbot+9937dc42271cd87d4b98@...kaller.appspotmail.com>,
        linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com,
        Eric Sandeen <sandeen@...hat.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [syzbot] WARNING in internal_create_group

On Thu, Aug 12, 2021 at 12:37:08AM +0300, Pavel Skripkin wrote:
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -1725,7 +1725,17 @@ static int nbd_dev_add(int index)
>  	refcount_set(&nbd->refs, 1);
>  	INIT_LIST_HEAD(&nbd->list);
>  	disk->major = NBD_MAJOR;
> +
> +	/* Too big first_minor can cause duplicate creation of
> +	 * sysfs files/links, since first_minor will be truncated to
> +	 * byte in __device_add_disk().
> +	 */
>  	disk->first_minor = index << part_shift;
> +	if (disk->first_minor > 0xff) {
> +		err = -EINVAL;
> +		goto out_free_idr;
> +	}
> +
>  	disk->minors = 1 << part_shift;
>  	disk->fops = &nbd_fops;
>  	disk->private_data = nbd;
>
>
> What to do you think about it?

This sounds reasonable and looks good to me.