Messages in this thread |  | | From | Andy Lutomirski <> | Date | Wed, 22 Oct 2014 19:19:44 -0700 | Subject | Re: [PATCH v5 4/4] fuse: Allow user namespace mounts |
| |
On Wed, Oct 22, 2014 at 5:22 PM, Seth Forshee <seth.forshee@canonical.com> wrote: > On Wed, Oct 22, 2014 at 02:51:56PM -0700, Andy Lutomirski wrote: >> On Wed, Oct 22, 2014 at 2:24 PM, Seth Forshee >> <seth.forshee@canonical.com> wrote: >> > Cc: Eric W. Biederman <ebiederm@xmission.com> >> > Cc: Serge H. Hallyn <serge.hallyn@ubuntu.com> >> > Cc: Andy Lutomirski <luto@amacapital.net> >> > Signed-off-by: Seth Forshee <seth.forshee@canonical.com> >> > --- >> > fs/fuse/inode.c | 4 ++-- >> > 1 file changed, 2 insertions(+), 2 deletions(-) >> > >> > diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c >> > index b88b5a780228..7d0e73e36e7b 100644 >> > --- a/fs/fuse/inode.c >> > +++ b/fs/fuse/inode.c >> > @@ -1201,7 +1201,7 @@ static void fuse_kill_sb_anon(struct super_block *sb) >> > static struct file_system_type fuse_fs_type = { >> > .owner = THIS_MODULE, >> > .name = "fuse", >> > - .fs_flags = FS_HAS_SUBTYPE, >> > + .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, >> > .mount = fuse_mount, >> > .kill_sb = fuse_kill_sb_anon, >> > }; >> > @@ -1233,7 +1233,7 @@ static struct file_system_type fuseblk_fs_type = { >> > .name = "fuseblk", >> > .mount = fuse_mount_blk, >> > .kill_sb = fuse_kill_sb_blk, >> > - .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, >> > + .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE | FS_USERNS_MOUNT, >> > }; >> > MODULE_ALIAS_FS("fuseblk"); >> > >> > -- >> > 1.9.1 >> > >> >> This is mostly a sign of my ignorance, but how does this actually end >> up working? I assume that the mounter opens /dev/fuse and then passes >> the fd to the mount call. Which userns is captured? The opener of >> /dev/fuse or the mounter of the fs? > > You're correct that the mounter passes the fd to /dev/fuse to the mount > call. The namespace of the mounter is used, but there's also a check to > make sure that's the same as that of the opener of /dev/fuse, otherwise > the mount fails.
As long as my nodev fix is either applied first or rejected,
Acked-by: Andy Lutomirski <luto@amacapital.net>
Although the LSM situation is still a mess. Serge, any thoughts?
--Andy
> > Seth
-- Andy Lutomirski AMA Capital Management, LLC
|  |