[HACKERS] semaphore usage "port based"?
Peter Jeremy
peterjeremy at optushome.com.au
Mon Apr 3 18:50:50 UTC 2006
On Mon, 2006-Apr-03 08:19:00 -0400, Daniel Eischen wrote:
>I don't really see what the problem is. ESRCH seems perfectly
>reasonable for trying to kill (even sig 0) a process from a
>different jail. If you're in a jail, then you shouldn't have
>knowledge of processes from other jails.
I agree in general. The problem here is that SysV IPC isn't
jail-aware - there's a single SysV IPC address space across the
physical system. This confuses (eg) postgres because it can
see the SHM for a postgres instance in another jail but kill(2)
claims that the process associated with that SHM doesn't exist.
There appear to be two solutions:
1) Add a sysctl to change cr_cansignal() and/or prison_check() to
make processes visible between jails.
2) Change SysV IPC to be jail-aware.
The former is trivial - but has a number of security implications.
The latter is much harder, there is apparently a RELENG_4 patch in
kern/48471 but it's not clear how much work would be necessary to
being it up to scratch.
--
Peter Jeremy
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