On Mon, Feb 10, 2025 at 8:45 PM Miklos Szeredi <mszeredi@xxxxxxxxxx> wrote:
>
> In theory overlayfs could support upper layer directly referring to a data
> layer, but there's no current use case for this.
>
> Originally, when data-only layers were introduced, this wasn't allowed,
> only introduced by the "datadir+" feture, but without actually handling
Spelling s/feture/feature
> this case, resuting in an Oops.
Spelling s/resuting/resulting
>
> Fix by disallowing datadir without lowerdir.
>
> Reported-by: Giuseppe Scrivano <gscrivan@xxxxxxxxxx>
> Fixes: 24e16e385f22 ("ovl: add support for appending lowerdirs one by one")
> Cc: <stable@xxxxxxxxxxxxxxx> # v6.7
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/overlayfs/super.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 86ae6f6da36b..b11094acdd8f 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1137,6 +1137,11 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
> return ERR_PTR(-EINVAL);
> }
>
> + if (ctx->nr == ctx->nr_data) {
> + pr_err("at least one non-data lowerdir is required\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> err = -EINVAL;
> for (i = 0; i < ctx->nr; i++) {
> l = &ctx->lower[i];
> --
> 2.48.1
>
