Date: Mon, 8 Mar 2004 11:43:05 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Tim Robbins <tjr@freebsd.org> Cc: freebsd-security@freebsd.org Subject: Re: Call for review: restricted hardlinks. Message-ID: <20040308104305.GJ10864@darkness.comp.waw.pl> In-Reply-To: <20040308102555.GA85110@cat.robbins.dropbear.id.au> References: <20040308093642.GI10864@darkness.comp.waw.pl> <20040308102555.GA85110@cat.robbins.dropbear.id.au>
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[-- Attachment #1 --] On Mon, Mar 08, 2004 at 09:25:55PM +1100, Tim Robbins wrote: +> > It adds two new sysctls: +> > +> > security.bsd.hardlink_check_uid +> > security.bsd.hardlink_check_gid +> > +> > If sysctl security.bsd.hardlink_check_uid is set to 1, unprivileged users +> > are not permitted to create hard links to files not owned by them. +> > If sysctl security.bsd.hardlink_check_gid is set to 1, unprivileged users +> > are not permitted to create hard links to files if they are not member +> > of file's group. +> > +> > For now user is able to create hardlinks to any files. +> +> It might be more consistent with other UNIX access checks (e.g. vaccess()) +> if having the same uid as the file was sufficient to link to it, +> without having to be a group member. I can't convince myself either way +> on this, but it's worth thinking about. So you need to set security.bsd.hardlink_check_uid and don't touch security.bsd.hardlink_check_gid. +> Also be aware that as a side effect of this patch, old applications that use +> the unlink()/link()/unlink() sequence instead of the rename() system call +> may not be able to rename files they don't own. Default values for those sysctls is 0, so system behaviour will change only on administrator request. -- Pawel Jakub Dawidek http://www.FreeBSD.org pjd@FreeBSD.org http://garage.freebsd.pl FreeBSD committer Am I Evil? Yes, I Am! [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFATE45ForvXbEpPzQRAktnAKCozr3T4aVZ/YedQe3eVJLjnLjyBQCeMxXU m6uCZnHVrBYZPWqFpq4V2t8= =P19i -----END PGP SIGNATURE-----
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