From: Miklos Szeredi <mszeredi@redhat.com>
Date: Mon, 14 Dec 2020 14:26:14 +0000 (+0100)
Subject: ovl: unprivieged mounts
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=459c7c565ac36ba09ffbf24231147f408fde4203;p=linux.git

ovl: unprivieged mounts

Enable unprivileged user namespace mounts of overlayfs.  Overlayfs's
permission model (*) ensures that the mounter itself cannot gain additional
privileges by the act of creating an overlayfs mount.

This feature request is coming from the "rootless" container crowd.

(*) Documentation/filesystems/overlayfs.txt#Permission model

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 6366adf81fa31..2bd570cbe8a45 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -2096,6 +2096,7 @@ static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
 static struct file_system_type ovl_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "overlay",
+	.fs_flags	= FS_USERNS_MOUNT,
 	.mount		= ovl_mount,
 	.kill_sb	= kill_anon_super,
 };