Re: [PATCH 1/2] ocfs2: Refuse to enable ocfs2 format for another filesystem

[Joseph Qi <joseph.qi@linux.alibaba.com>]

On 9/2/26 9:36 PM, Jan Kara wrote:
> It is possible to issue Q_QUOTAON quotactl(2) e.g. for ext4 filesystem
> requesting to enable quota using ocfs2 quota format. With suitable
> passed arguments this can get upto ocfs2_local_check_quota_file() where
> the passed superblock is from the ext4 filesystem and that can cause all
> sorts of interesting things, most likely crashes. As ocfs2 quotas are
> specific to ocfs2 filesystem, verify we are indeed enabling quotas
> there.
> 
> Signed-off-by: Jan Kara <jack@suse.cz>

Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> ---
>  fs/ocfs2/quota_local.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
> index f55810c59b1b..97dee8ee6096 100644
> --- a/fs/ocfs2/quota_local.c
> +++ b/fs/ocfs2/quota_local.c
> @@ -171,6 +171,10 @@ static int ocfs2_local_check_quota_file(struct super_block *sb, int type)
>  	struct ocfs2_disk_dqheader *dqhead;
>  	int status, ret = 0;
>  
> +	/* OCFS2 quota format is supported only for OCFS2 filesystems */
> +	if (strcmp(sb->s_type->name, "ocfs2"))
> +		goto out_err;
> +
>  	/* First check whether we understand local quota file */
>  	status = ocfs2_read_quota_block(linode, 0, &bh);
>  	if (status) {