From dacfd001eaf252a81537aece602ae2fc16e6ebd5 Mon Sep 17 00:00:00 2001 From: Taylor Jackson Date: Thu, 8 Feb 2024 03:02:54 +0000 Subject: [PATCH] fs/mnt_idmapping.c: Return -EINVAL when no map is written MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, it is possible to create an idmapped mount using a user namespace without any mappings. However, this yields an idmapped mount that doesn't actually map the ids. With the following change, it will no longer be possible to create an idmapped mount when using a user namespace with no mappings, and will instead return EINVAL, an “invalid argument” error code. Reviewed-by: Christian Brauner Signed-off-by: Taylor Jackson Link: https://lore.kernel.org/r/20240208-mnt-idmap-inval-v2-1-58ef26d194e0@me.com Signed-off-by: Christian Brauner --- fs/mnt_idmapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c index 64c5205e2b5e..3c60f1eaca61 100644 --- a/fs/mnt_idmapping.c +++ b/fs/mnt_idmapping.c @@ -214,7 +214,7 @@ static int copy_mnt_idmap(struct uid_gid_map *map_from, * anything at all. */ if (nr_extents == 0) - return 0; + return -EINVAL; /* * Here we know that nr_extents is greater than zero which means