named is not able to generate core dumps

Mark Andrews Mark_Andrews at isc.org
Tue Dec 4 15:57:06 UTC 2007


> On Tue, Dec 04, 2007 at 01:55:26PM +0000, George Ross wrote:
> > > I've tried get core dump from named on linux system (yes, Fedora and
> > > RHEL :) ) ...
> > 
> > Are you starting it as root and then having it setuid() to something else?
> > From man 2 setuid:
> > 
> >        If  uid  is  different  from the old effective uid, the process will
>  be
> >        forbidden from leaving core dumps.
> > 
> > -- 
> > Dr George D M Ross, School of Informatics, University of Edinburgh
> >     Kings Buildings, Mayfield Road, Edinburgh, Scotland, EH9 3JZ
> > Mail: gdmr at inf.ed.ac.uk   Voice: +44 131 650 5147   Fax: +44 131 667 7209
> >  PGP: 1024D/AD758CC5  B91E D430 1E0D 5883 EF6A  426C B676 5C2B AD75 8CC5
> > 
> > 
> 
> Yes, this is problem. I have to start named without -u option.
> Thanks.
> 
> Adam
> 
> -- 
> Adam Tkac, Red Hat, Inc.

	BIND 9 theoretically has code that should allow core dumps
	even after setuid() is called under Linux.  I, personally,
	have not investigated this.

bin/named/unix/os.c
#if defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_DUMPABLE)
        /*
         * Restore the ability of named to drop core after the setuid()
         * call has disabled it.
         */
        prctl(PR_SET_DUMPABLE,1,0,0,0);
#endif

	Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org


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