[HACKERS] semaphore usage "port based"?
Robert Watson
rwatson at FreeBSD.org
Mon Apr 3 22:10:42 UTC 2006
On Mon, 3 Apr 2006, Marc G. Fournier wrote:
>> The problem here is actually that two postgres instances are trying to use
>> the same sempahore when they are actually different postgres instances.
>
> No, the problem here is that kill(PID, 0) reports that a PID is 'not in use'
> when, in fact, it is, but in a different jail ... can someone explain to me
> how 'not hiding that fact' increases information leakage, or causes a
> security problem? I could see it if I could then proceed to kill that
> process from a seperate jail, but I don't see what as possible ...
So if it's using a different semaphore, why is it finding the semaphore of
another Postgres session and trying to use that? The problem you're
describing is a property of a collision on a semaphore. If there's no
semaphore collision, how would it ever find the pid from another jail?
Robert N M Watson
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