Re: Shared memory and FreeBSD's jail()

lister <lister@primetime.com> writes:
>  At the BSDCan tutorial last week on jails (and several other times)
> there was discussion regarding Postgres's use of system V style
> shared memory, and an unfortunate side effect of making jail() less
> secure. Specifically, to allow Postgres to operate in a jail()ed
> environment, the sysctl :
> jail.sysvipc_allowed=1
>  has to be set. This allows ALL jails to access the memory, at the least
> leaving Postgres open to attack, at the worst allowing a door into who
> knows what security breach.

This claim is really pretty bogus, since there is still standard
file-permission-like security on the shared memory.  Only if you give
usage of the postgres account to processes running in other jails is
there any risk.

            regards, tom lane