Re: ntsec patch 1: uid==gid, chmod, alloc_sd, is_grp_member

[Corinna Vinschen <cygwin-patches at cygwin dot com>]

On Thu, Nov 14, 2002 at 06:23:23PM +0100, Corinna Vinschen wrote:
> On Thu, Nov 14, 2002 at 12:03:24PM -0500, Pierre A. Humblet wrote:
> > If you are emulated, you already have the token in the cygheap->user.
> > There is no need to open the thread, see how it's done e.g.in setegid.
> 
> Good point.
> 
> > You want to know if the file owner uid is in the group of the file gid.
> > Write a new routine scanning the /etc/group file until you find the gid.
> > Then scan the members of that group to see if the uid is in it.
> > That's it (well, there will be mutex too, against threads rereading /etc/group).
> 
> Also a good point.  I'm going to rewrite is_grp_member().

I've checked in a patch to getgroups32() and is_grp_member().

getgroups32() now only makes sense for the current user again.  It uses
the impersonation token if impersonated.

is_grp_member() calls getgroups32() only for the current user and
scans passwd and group otherwise, trying to be more efficient.

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin@cygwin.com
Red Hat, Inc.