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From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	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, 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: Tue, 17 Jan 2012 17:23:09 +0100	[thread overview]
Message-ID: <20120117162309.GA16336@redhat.com> (raw)
In-Reply-To: <c4c1a0e710a50e48221aa28d2b60b486ab686369.1326673414.git.luto@amacapital.net>

On 01/15, 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.
>
> ...
>
> +	if (!(current->no_new_privs && !is_chrooted) &&
> +	    !capable(CAP_SYS_CHROOT))

I must have missed something. How no_new_privs can help if fs->users != 1 ?

Oleg.


  parent reply	other threads:[~2012-01-17 16:23 UTC|newest]

Thread overview: 33+ 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 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
2012-01-16  0:45     ` Linus Torvalds
2012-01-16  1:08     ` Andy Lutomirski
2012-01-16  1:08       ` Andy Lutomirski
2012-01-16 19:26   ` Colin Walters
2012-01-16 19:26     ` Colin Walters
2012-01-16 20:18     ` Andy Lutomirski
2012-01-16 20:18       ` Andy Lutomirski
2012-01-17 10:14     ` Jamie Lokier
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 [this message]
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  1:04   ` Andy Lutomirski
2012-01-16 20:49 ` Colin Walters
2012-01-16 20:49   ` Colin Walters
2012-01-16 21:25   ` Andy Lutomirski
2012-01-16 21:25     ` Andy Lutomirski
2012-01-16 21:47     ` Colin Walters
2012-01-16 21:47       ` Colin Walters
2012-01-16 21:57       ` Andy Lutomirski
2012-01-16 21:57         ` Andy Lutomirski

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