[fedfs-utils] [PATCH] libnsdb: set file mode on open(..., O_CREAT)

[Jeff Layton]

On Sun, 10 Jul 2011 22:13:37 +0100
Chuck Lever <chucklever at gmail.com> wrote:

> On Thu, Jul 7, 2011 at 9:33 PM, Jeff Layton <jlayton at redhat.com> wrote:
> > open(2) with O_CREAT requires the caller to provide a mode.
> 
> Interesting.  I assumed that the gcc system headers would flag
> something like this and warn, but I haven't seen such a warning.
> 

It does warn, but you may have to set a -D compiler flag. This bug
caused the build to fail via rpmbuild.

> > (Chuck: Does 0666 make sense here?)
> 
> /me pages in just enough to answer...
> 
> I've confirmed with an RH-local LDAP expert that we should drop cert
> files into a directory under /var/lib/fedfs.  Such a directory would
> be owned by the FEDFS user and group.
> 
> Right now this function is invoked by the nsdbparams command, running
> as root; and the rpc.fedfsd server, running with dropped privileges as
> the FEDFS user and group.   These programs can create, replace, or
> delete these cert files.
> 
> Cert files will be read by user processes that handle junction
> resolution, and by NSDB administrative programs... these programs run
> as normal users, no guarantee that they will have any kind of special
> privileges.
> 
> Thus I think cert files should be owned by the FEDFS user and group
> whether this function is invoked by a root caller or a caller running
> as the FEDFS user and group.  A cert file can be readable, but should
> not be writeable, by the world.
> 
> I doubt the function works quite this way right at the moment.  This
> is one of the areas that still needs to be completed.
> 
> Another concern is how to tag these files with the correct SELinux
> contexts as they are created...
> 
> > Signed-off-by: Jeff Layton <jlayton at redhat.com>
> > ---
> >  src/libnsdb/nsdb.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/src/libnsdb/nsdb.c b/src/libnsdb/nsdb.c
> > index cad92eb..00be913 100644
> > --- a/src/libnsdb/nsdb.c
> > +++ b/src/libnsdb/nsdb.c
> > @@ -532,7 +532,7 @@ nsdb_new_certfile(const char *certdata, const unsigned int certlen,
> >                goto out;
> >        }
> >
> > -       fd = open(pathbuf, O_WRONLY | O_SYNC | O_CREAT | O_EXCL);
> > +       fd = open(pathbuf, O_WRONLY | O_SYNC | O_CREAT | O_EXCL, 0666);
> >        if (fd == -1) {
> >                xlog(D_GENERAL, "%s: Failed to open %s: %m",
> >                        __func__, pathbuf);
> 


-- 
Jeff Layton <jlayton at poochiereds.net>