From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Casey Schaufler <casey@schaufler-ca.com>,
Jamie Lokier <jamie@shareable.org>,
Will Drewry <wad@chromium.org>,
linux-kernel@vger.kernel.org, keescook@chromium.org,
john.johansen@canonical.com, serge.hallyn@canonical.com,
coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com,
djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org,
jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com,
penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu,
akpm@linux-foundation.org, khilman@ti.com,
borislav.petkov@amd.com, amwang@redhat.com, oleg@redhat.com,
ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de,
dhowells@redhat.com, daniel.lezcano@free.fr,
linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, olofj@chromium.org,
mhalcrow@google.com, dlaor@redhat.com, corbet@lwn.net,
alan@lxorguk.ukuu.org.uk
Subject: Re: [PATCH 4/4] Allow unprivileged chroot when safe
Date: Sun, 15 Jan 2012 16:45:31 -0800 [thread overview]
Message-ID: <CA+55aFybUcL2M9qZ91MF-PAwNSO6AdEfHXv_i00sftHyTb3ocQ@mail.gmail.com> (raw)
In-Reply-To: <c4c1a0e710a50e48221aa28d2b60b486ab686369.1326673414.git.luto@amacapital.net>
On Sun, Jan 15, 2012 at 4:37 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> Chroot can easily be used to subvert setuid programs. If no_new_privs,
> then setuid programs don't gain any privilege, so allow chroot.
>
> Because chroot is an easy way to break out of chroot jail, CAP_SYS_ADMIN
> is still required if the caller is already chrooted.
So I think this whole chroot thing needs more people looking at it. I
brought up chroot as an example, but there may be other reasons why
you don't want user chrooting things than just the setuid confusion.
There's also the whole issue with doing things like local non-root
bind mounts, which are arguably more useful than chroot, and which are
disallowed for similar reasons. So I don't think chroot is all that
special.
Linus
next prev parent reply other threads:[~2012-01-16 0:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 0:37 [PATCH v2 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot Andy Lutomirski
2012-01-16 0:37 ` [PATCH v2 1/4] Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs Andy Lutomirski
2012-01-16 17:33 ` Oleg Nesterov
2012-01-16 20:15 ` Andy Lutomirski
2012-01-16 0:37 ` [PATCH v2 2/4] Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS Andy Lutomirski
2012-01-16 0:37 ` [PATCH v2 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs Andy Lutomirski
2012-01-16 0:37 ` [PATCH 4/4] Allow unprivileged chroot when safe Andy Lutomirski
2012-01-16 0:45 ` Linus Torvalds [this message]
2012-01-16 1:08 ` Andy Lutomirski
2012-01-16 19:26 ` Colin Walters
2012-01-16 20:18 ` Andy Lutomirski
2012-01-17 10:14 ` Jamie Lokier
2012-01-16 20:06 ` Al Viro
2012-01-16 20:15 ` Andy Lutomirski
2012-01-16 20:26 ` Al Viro
2012-01-17 16:23 ` Oleg Nesterov
2012-01-17 16:31 ` Andy Lutomirski
2012-01-16 1:04 ` [PATCH v2 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot Andy Lutomirski
2012-01-16 20:49 ` Colin Walters
2012-01-16 21:25 ` Andy Lutomirski
2012-01-16 21:47 ` Colin Walters
2012-01-16 21:57 ` Andy Lutomirski
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