[PATCH] Dangerous jail()<->ioctl interactions.

Wojciech A. Koszek dunstan at freebsd.czest.pl
Mon Feb 21 14:11:20 PST 2005


Hello hackers,
I would like to let you know I've been doing [partial] audit of ioctl()
code. There are some places, which may interest you. These are:

sys/cam/cam_xpt.c
sys/contrib/ipfilter/netinet/ip_fil.c
sys/contrib/pf/net/pf_ioctl.c
sys/dev/ata/ata-all.c
sys/dev/md/md.c
sys/geom/geom_ctl.c

Those files contain ioctl()s, which let us to interact between jailed processes
and each of these subsystems. Although files like /dev/mdctl should not
appear in /dev with normal DEVFS rulesets, I think it would be better if FreeBSD had
those ioctl() disabled within jail()ed environment. There is probably one
reason for keeping ipf/pf, since someone may want fetch information about NATed
connections.

How to repeat? Reproducing is very simple. Test environment:
   
  # jail / hostname 127.0.0.1 /bin/csh
 
After this step you can monipulate ATA devices:

  # atacontrol detach <number>
 
Create/remove md(4) devices:

  # mdconfig -a -t malloc -s 100M
  # mdconfig -d -u md0

Manipulate cam(4) devices:
 
  # camcontrol reset cd0
  # camcontrol eject cd0

Manipulate gbde devices:

  # mdconfig -a -t malloc -s 10M
  # gbde

Manipulate ipnat/ipf/pf rules:
  # ipnat -f /etc/ipnat.conf
  # ipnat -CF a
  # pfctl -f /etc/pf.some.rules
  # ipf -f /etc/ipf.some.rules

Patches with simple suser() tests added are available at:
(sys/cam/cam_xpt.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.1.jail

(sys/contrib/ipfilter/netinet/ip_fil.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.2.jail 

(/usr/src/sys/contrib/pf/net/pf_ioctl.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.3.jail

(/usr/src/sys/dev/ata/ata-all.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.4.jail
(If someone would like to commit it, I can also write style patch).

(/usr/src/sys/dev/md/md.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.5.jail

(/usr/src/sys/geom/geom_ctl.c):
http://FreeBSD.czest.pl/dunstan/FreeBSD/diff.6.jail

And comments are welcome. If you find some of these patches useful, please
let me know.
Regards,
-- 
* Wojciech A. Koszek && dunstan at FreeBSD.czest.pl


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