Обсуждение: Reading from a read-only BLOB is allowed

Hi!

It seems that postgres allows writing to a read-only blob opened like:

    fd = lo_open (cnc, oid, INV_READ);

I've attached a simple test case and the Makefile to build it.

I'm using postgresql 7.3.3 (7.3.3-1 is the debian package version).

Is that the intended behaviour or is it a bug?

-Gonzalo

P.S.: please, CC me as I'm not suscribed to this list. Thanks.

--
Gonzalo Paniagua Javier <gonzalo@gnome-db.org>
http://www.gnome-db.org/~gonzalo/

Gonzalo Paniagua Javier <gonzalo@gnome-db.org> writes:
> It seems that postgres allows writing to a read-only blob opened like:
>     fd = lo_open (cnc, oid, INV_READ);

AFAICS from the code, INV_READ/WRITE attached to lo_open only determine
the kind of lock taken on the LO (shared or exclusive).  Not sure
whether it's a bug to prohibit the other kind of access or not.

Note that there's no "security" issue here, since anyone is allowed to
write any LO anyway.

            regards, tom lane