Can Firefox break out of a jail

[Erich Dollansky]

Hi,

I do some experimenting with jails at the moment on a FreeBSD 10.0
machine. The jails are all setup manually according to the handbook and
man jail. Each jail gets a name and an IP address. Individual ports are
then installed via the ports tree.

X is running on the host system. Telnet is used to connect to the jails.

When I install now firefox in a jail and also in the host system, I get
the following behaviour.

Scene A

Firefox runs already on the host system. I start then firefox inside
the jail firefox. It all seems fine as long as I do not use the history
or want to save the visited page. The jailed firefox sees then the
history of the firefox running on the host.

Scene B

Firefox is first started inside the jail firefox. When then the host
system also starts a firefox, this firefox sees now the history and the
filesystem of the jailed firefox.

Is it X that allows the jailed firefox to communicate directly with
firefox running directly on the host?

Is there then a way to secure the system?

I have tried then programs like gedit or kate and saw only the
behaviour I expected. Both programs either saw only resources from
inside the jail or from outside but never resources from the other side
of the fence.

Erich