Skip site navigation (1) Skip section navigation (2)

Re: Fix for initdb failures on Vista

From: Magnus Hagander <magnus(at)hagander(dot)net>
To: Andrew Dunstan <andrew(at)dunslane(dot)net>
Cc: Dave Page <dpage(at)pgadmin(dot)org>,pgsql-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: Fix for initdb failures on Vista
Date: 2008-02-29 15:25:32
Message-ID: 20080229152532.GN13806@svr2.hagander.net (view raw or flat)
Thread:
Lists: pgsql-patches
On Fri, Feb 29, 2008 at 12:17:51AM -0500, Andrew Dunstan wrote:
> 
> 
> Dave Page wrote:
> >The attached patch fixes problems reported primarily on Vista, but
> >also on some Windows 2003 and XP installations in which initdb reports
> >that it cannot find postgres.exe.
> >
> >This occurs because of security-related changes implemented in Windows
> >Vista and recent patches on older OS's. When running initdb or pg_ctl
> >we currently create a restricted security token with the
> >Administrators and Power Users groups (and thus their privileges)
> >removed and re-execute the same program using the restricted token.
> >This ensures that the process is run without potentially dangerous
> >privileges no matter what user account it was started from. On Vista
> >and friends however, the default DACL (list of Access Control Entries)
> >used in the restricted token contains Administrators (the group) &
> >System when we run as Administrator, vs. User + System when run as
> >other users. Because we then drop Administrators, we are left with
> >only the System ACE in the DACL, which does not allow us to use
> >CreatePipe()/CreateProcess().
> >
> >To fix this, when we create the restricted process, we initially start
> >it in suspended mode. We modify it's DACL to explicitly add an ACE for
> >the current user, and then resume the child process. This remains
> >secure because administrative privileges are granted to the groups
> >that we've dropped, not the user itself.
> >
> >I've tested on Vista and XP, but additional testing would be useful
> >(Andrew, Magnus?). Please apply to head, 8.3 and 8.2
> >
> >  
> 
> This appears to work for initdb. But "make check" fails after the initdb 
> stage, I think because pg_regress doesn't use pg_ctl to start the 
> postmaster. The log just reads "Access is denied'"
> 
> I don't have too much difficulty with that as long as we stipulate that 
> postgres has to be built, or at least checked, as a non-privileged user 
> (c.f. recent discussion of building RPMs as root). Alternatively, we 
> should also patch pg_regress.c
> 

I noticed that as well when looking at the code, but since I ran my tests
on non-vista platforms I didn't hit the actual problem.

Dave - it shuold be a simple case of adding the same line of code to the
regression tests, no?

Meanwhile, I'll apply what we have with my additios and cleanups per mine
and Heikkis comments, because they fix the most important codepaths.

//Magnus

In response to

Responses

pgsql-patches by date

Next:From: Dave PageDate: 2008-02-29 15:28:19
Subject: Re: Fix for initdb failures on Vista
Previous:From: Tom LaneDate: 2008-02-29 15:02:49
Subject: Re: DTrace probe patch for OS X Leopard

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group