[rsbac] change chroot syscall by rsbac_jail one

[Javier J. Martínez Cabezón]

Hi, I was thinking why don't you change directly the chroot syscall
(NR_61 in svn) by the rsbac syscall_jail one?

You could add a config option CONFIG_CHANGE_CHROOT_BY_JAIL, if defined
all chroots calls will "jump" to rsbac_jail one.
I think that userspace programs will use rsbac_jail without knowing
the change since they still calling sys_chroot.

So I think you can do the same as some rootkits do...change syscall_table :).

Configuration of the jail could be done using data from kerneland, by
default the behaviour (parameters) of rsbac_jail could be the same as
chroot, only changing / dir but with all restrictions of rsbac_jail,
we could for example indicate later which will be the maximum
capabilities, IP etc...

I think with this one problem could be solved (people don't want to
change software source code to use jails) making it transparent for
the user.

What do you think?