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From: Andy Lutomirski <luto@amacapital.net>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Colin Walters <walters@verbum.org>,
	Will Drewry <wad@chromium.org>,
	linux-kernel@vger.kernel.org,
	Casey Schaufler <casey@schaufler-ca.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jamie Lokier <jamie@shareable.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, 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 v3 4/4] Allow unprivileged chroot when safe
Date: Mon, 30 Jan 2012 14:28:05 -0800	[thread overview]
Message-ID: <CALCETrWX6OsuOcD+ctyNAx7xyU_DL1_Mqb9+MYs5J9xubX1vmA@mail.gmail.com> (raw)
In-Reply-To: <1327961884.5882.11.camel@gandalf.stny.rr.com>

On Mon, Jan 30, 2012 at 2:18 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Mon, 2012-01-30 at 16:58 -0500, Colin Walters wrote:
>> On Mon, 2012-01-30 at 08:17 -0800, Andy Lutomirski 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.
>>
>> Is this needed/desired by anyone now, or are you just using it to "demo"
>> NO_NEW_PRIVS?  I don't see it as very useful on its own, since in any
>> "container"-type chroot you really want /proc and /dev, and your patch
>> doesn't help with that.
>>
>> System daemons that do chroot for a modicum of security already start
>> privileged, so this doesn't help them either.
>
> I thought this was all for sandboxing? If a browers (or user) wants to
> run some untrusted code, perhaps a chroot is the best way to do so. It
> just will break if it needs to access /proc or /dev. And perhaps we
> don't want untrusted code accessing /proc and /dev.

True.  A BPF seccomp filter that disables open, bind, connect, rename,
unlink, etc may be better, though.

(I like this patch, although I don't think it's at all essential.  It
could certainly be made more flexible and more useful, but it would
get considerably more complicated in the process.)

--Andy

  reply	other threads:[~2012-01-30 22:28 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 16:17 [PATCH v3 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 1/4] Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs Andy Lutomirski
2012-02-01 18:14   ` Kees Cook
2012-01-30 16:17 ` [PATCH v3 2/4] Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs Andy Lutomirski
2012-02-01 19:02   ` Kees Cook
2012-02-01 20:35     ` Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 4/4] Allow unprivileged chroot when safe Andy Lutomirski
2012-01-30 21:58   ` Colin Walters
2012-01-30 22:10     ` Andy Lutomirski
2012-01-30 22:41       ` Colin Walters
2012-01-30 22:43         ` Andy Lutomirski
2012-01-30 23:10           ` Colin Walters
2012-01-30 23:15             ` Andy Lutomirski
2012-01-30 23:55               ` Colin Walters
2012-01-31  0:13                 ` Andy Lutomirski
2012-01-30 22:18     ` Steven Rostedt
2012-01-30 22:28       ` Andy Lutomirski [this message]
2012-01-30 22:38       ` Will Drewry
2012-01-30 22:48         ` Colin Walters
2012-01-30 22:51         ` Andy Lutomirski
2012-02-09  9:35           ` Vasiliy Kulikov

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