From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Landley Subject: Re: [RFC][PATCH 0/3] vfs: Detach mounts on unlink. Date: Sat, 05 Oct 2013 19:22:00 -0500 Message-ID: <1381018920.1974.167@driftwood> References: <87li281wx6.fsf_-_@xmission.com> <1381014462.1974.162@driftwood> <20131005232451.GX13318@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; DelSp=Yes; Format=Flowed Content-Transfer-Encoding: 8BIT Cc: Linus Torvalds , "Eric W. Biederman" , Miklos Szeredi , "Serge E. Hallyn" , Linux-Fsdevel , Kernel Mailing List , Andy Lutomirski To: Al Viro Return-path: In-Reply-To: <20131005232451.GX13318@ZenIV.linux.org.uk> (from viro@ZenIV.linux.org.uk on Sat Oct 5 18:24:51 2013) Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 10/05/2013 06:24:51 PM, Al Viro wrote: > On Sat, Oct 05, 2013 at 04:17:55PM -0700, Linus Torvalds wrote: > > On Sat, Oct 5, 2013 at 4:07 PM, Rob Landley wrote: > > > > > > A todo item I've had _forever_ is fixing chroot() to not be > broken so that > > > you can trivially break out of a chroot via: > > > > What drugs are you on? > > > > Your example is moronic, and against all _documented_ uses of > chroot. > > ... and even fixing that example (chroot *can* be escaped, if you can > call chroot(2) - mkdir /foo, chdir /, chroot /foo, chroot .. and you > are out) Um, wasn't that my example? > the whole thing is idiocy - chroot() is not and has never been > root-proof > and anybody expecting it to be has failed to read any number of FAQs > out > there. Which is why I was proposing modifying it so lxc and containers didn't have to use pivot_root() instead, with all the logic to rehome existing processes and the weird "this path is relative the old root, this path is relative to the new root" syntax from initial ramdisks. Rob