mount_nullfs inside a jail

[Boris Samorodov]

On Tue, 24 Jul 2007 16:45:49 +0200 Pawel Jakub Dawidek wrote:
> On Tue, Jul 24, 2007 at 06:03:47PM +0400, Boris Samorodov wrote:
> > On Mon, 23 Jul 2007 15:33:33 +0200 Pawel Jakub Dawidek wrote:

> > > As you can see, nullfs doesn't have 'jail' flag. The only jail-friendly
> > > file system currently is ZFS. Nullfs is a good candidate for a
> > > jail-friendly file system, but is not marked as such yet.
> > 
> > Does somebody know if only a flag is missing or not?

> You may try changing the line in /sys/fs/nullfs/null_vfsops.c from:

> VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);

> to:

> VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);

This didn't help:
-----
btest# sysctl security.jail
security.jail.jailed: 1
security.jail.mount_allowed: 1
security.jail.chflags_allowed: 1
security.jail.allow_raw_sockets: 0
security.jail.enforce_statfs: 2
security.jail.sysvipc_allowed: 1
security.jail.socket_unixiproute_only: 1
security.jail.set_hostname_allowed: 1
btest# lsvfs
Filesystem                        Refs Flags
-------------------------------- ----- ---------------
ufs                                  6 
nfs                                  0 network
procfs                               0 synthetic
devfs                                3 synthetic
ntfs                                 0 
msdosfs                              0 
nfs4                                 0 network
nullfs                               1 loopback, jail
cd9660                               0 read-only
btest# df
Filesystem  1K-blocks     Used     Avail Capacity  Mounted on
/dev/da0s1d 945804208 22136782 848003090     3%    /
btest# mount /usr/ports/distfiles /mnt
mount: /usr/ports/distfiles : Operation not permitted
-----

Thanks for the suggestion though.

> but I don't think anyone did any security analysis of this yet.


WBR
-- 
Boris Samorodov (bsam)
Research Engineer, http://www.ipt.ru Telephone & Internet SP
FreeBSD committer, http://www.FreeBSD.org The Power To Serve