From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Becker Subject: Re: New reflink(2) syscall Date: Mon, 4 May 2009 14:03:56 -0700 Message-ID: <20090504210356.GA25313@mail.oracle.com> References: <1241443016.3023.51.camel@localhost.localdomain> <20090504163514.GB31249@mail.oracle.com> <1241458669.3023.203.camel@localhost.localdomain> <20090504180855.GE31249@mail.oracle.com> <1241465446.3023.228.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: James Morris , lsm , linux-fsdevel@vger.kernel.org To: Stephen Smalley Return-path: Content-Disposition: inline In-Reply-To: <1241465446.3023.228.camel@localhost.localdomain> Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon, May 04, 2009 at 03:30:46PM -0400, Stephen Smalley wrote: > > Yeah, I really don't want to create multiple behaviors. I > > wasn't proposing the "behaves differently on CAP_CHOWN," I was trying to > > clarify what you were thinking. > > Given that normally users can't create files with other ownerships, it > seemed that we might want to require CAP_CHOWN or some other capability > in order to reflink(2) a file that isn't owned by the fsuid of the > process. Possibly is_owner_or_cap(), i.e. owner or CAP_FOWNER, would be > suitable. Yeah, the more I think about it the more I agree. It's a simple story - you're creating a file with ownership !you, you need owner_or_cap. This also prevents a fun quota DoS. Joel -- "Well-timed silence hath more eloquence than speech." - Martin Fraquhar Tupper Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127