unprivileged users are able to kill certain jailed processes

Hello,

unprivileged users of the host environment can see jailed processes with 
the same user ID. Furthermore they are able to send signals to these 
processes. I think since users are not allowed to imprison processes 
there is no reason why they should see them or even kill them.

Someone pointed me to this issue and I want to know what you think about 
this.

These are some steps to reproduce:

   root_at_host # jail -Uuserxy / localhost 127.0.0.1 /bin/sleep 12345&

   root_at_host # ps a | grep sleep 
 

    2255  p2  IJ     0:00,01 /bin/sleep 12345

   login as 'userxy'

   userxy_at_host $ ps a | grep sleep
    2255  p2  IJ     0:00,01 /bin/sleep 12345

   userxy_at_host $ ps a | grep sleep
    [nothing]

This is a suggestion to eliminate this behaviour. I appreciate further 
testing because I hadn't much time to do it.

=== patch starts here ===
--- src/sys/kern/kern_jail.c.orig    Wed Sep 28 02:30:56 2005
+++ src/sys/kern/kern_jail.c Sun Feb  5 14:42:00 2006
_at__at_ -405,6 +405,9 _at__at_
  			return (ESRCH);
  		if (cred2->cr_prison != cred1->cr_prison)
  			return (ESRCH);
+	} else {
+		if (jailed(cred2) && suser_cred(cred1, 0))
+			return (ESRCH);
  	}

  	return (0);
=== patch ends here ===


Regards
Björn