6.12-stable review patch. If anyone has any objections, please let me know.
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From: Miklos Szeredi mszeredi@redhat.com
commit eb3a04a8516ee9b5174379306f94279fc90424c4 upstream.
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+" feature, but without actually handling this case, resulting in an Oops.
Fix by disallowing datadir without lowerdir.
Reported-by: Giuseppe Scrivano gscrivan@redhat.com Fixes: 24e16e385f22 ("ovl: add support for appending lowerdirs one by one") Cc: stable@vger.kernel.org # v6.7 Reviewed-by: Amir Goldstein amir73il@gmail.com Reviewed-by: Alexander Larsson alexl@redhat.com Reviewed-by: Christian Brauner brauner@kernel.org Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/overlayfs/super.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1119,6 +1119,11 @@ static struct ovl_entry *ovl_get_lowerst 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];