From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Andres Freund <andres(at)2ndquadrant(dot)com> |
Cc: | Marti Raudsepp <marti(at)juffo(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pg_shmem_allocations view |
Date: | 2014-08-18 15:56:44 |
Message-ID: | CA+TgmoY+zPmbbyToJfgsqq8P9r=qBC7zsnzvXL355e5KkEJcZg@mail.gmail.com |
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Lists: | pgsql-hackers |
On Fri, Aug 15, 2014 at 4:20 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2014-08-15 11:12:11 +0300, Marti Raudsepp wrote:
>> Hi
>> On Thu, May 8, 2014 at 4:28 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
>> > Ok. A new version of the patches implementing that are
>> > attached. Including a couple of small fixups and docs. The latter aren't
>> > extensive, but that doesn't seem to be warranted anyway.
>>
>> Is it really actually useful to expose the segment off(set) to users?
>> Seems to me like unnecessary internal details leaking out.
>
> Yes. This is clearly developer oriented and I'd more than once wished I
> could see where some stray pointer is pointing to... That's not really
> possible without something like this.
Unfortunately, that information also has some security implications.
I'm sure someone trying to exploit any future stack-overrun
vulnerability will be very happy to have more rather than less
information about the layout of the process address space.
I fully agree with the idea of exposing the amount of free memory in
the shared memory segment (as discussed in other emails); that's
critical information. But I think exposing address space layout
information is of much less general utility and, really, far too
risky.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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