mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-06-21 15:43:21 +02:00
Jeff Layton
c5d6cac286
Commite1c5ae59c0("fs: don't allow non-init s_user_ns for filesystems without FS_USERNS_MOUNT") prevents the mount of any filesystem inside a container that doesn't have FS_USERNS_MOUNT set. This broke NFS mounts in our containerized environment. We have a daemon somewhat like systemd-mountfsd running in the init_ns. A process does a fsopen() inside the container and passes it to the daemon via unix socket. The daemon then vets that the request is for an allowed NFS server and performs the mount. This now fails because the fc->user_ns is set to the value in the container and NFS doesn't set FS_USERNS_MOUNT. We don't want to add FS_USERNS_MOUNT to NFS since that would allow the container to mount any NFS server (even malicious ones). Add a new FS_USERNS_DELEGATABLE flag, and enable it on NFS. Fixes:e1c5ae59c0("fs: don't allow non-init s_user_ns for filesystems without FS_USERNS_MOUNT") Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260129-twmount-v1-1-4874ed2a15c4@kernel.org Acked-by: Anna Schumaker <anna.schumaker@oracle.com> Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@futurfusion.io> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>