Re: pg_upgrade and umask

On Fri, Mar 09, 2012 at 11:33:36AM -0500, Bruce Momjian wrote:
> On Fri, Mar 09, 2012 at 10:41:53AM -0500, Tom Lane wrote:
> > Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > > The problem is that these files are being created often by shell
> > > redirects, e.g. pg_dump -f out 2> log_file. There is no clean way to
> > > control the file creation permissions in this case --- only umask gives
> > > us a process-level setting. Actually, one crafty idea would be to do
> > > the umask only when I exec something, and when I create the initial
> > > files with the new banner you suggested. Let me look into that.
> >
> > You could create empty log files with the desired permissions, and then
> > do the execs with >>log_file, and thereby not have to globally change
> > umask.
>
> Yes, that is what I have done, with the attached patch. I basically
> wrapped the fopen call with umask calls, and have the system() call
> wrapped too. That takes care of all the files pg_upgrade creates.
>
> > > Frankly, the permissions are already being modified by the default
> > > umask, e.g. 0022. Do we want a zero umask?
> >
> > I'm not so worried about default umask; nobody's complained yet about
> > wrong permissions on pg_upgrade output files. But umask 077 would be
> > likely to do things like get rid of group access to postgresql.conf,
> > which some people intentionally set.
>
> Yes, that was my conclusion too, but I wanted to ask. FYI, this doesn't
> affect the install itself, just what pg_upgrade changes, and it doesn't
> touch postgresql.conf, but, as you, I am worried there might be
> long-term problems with an aggressive umask that covered the entire
> executable.

I ended up creating fopen_priv to centralize the umask calls to a single
function, and added an is_priv boolean to exec_prog for the same purpose.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +