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From: Andy Lutomirski <luto@amacapital.net>
To: Will Drewry <wad@chromium.org>, linux-kernel@vger.kernel.org
Cc: 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, 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, Al Viro <viro@zeniv.linux.org.uk>,
	Andy Lutomirski <luto@amacapital.net>
Subject: [PATCH v3 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs
Date: Mon, 30 Jan 2012 08:17:28 -0800	[thread overview]
Message-ID: <9a520b74ad5dc14a3d6950b6d63a64714adbdd7d.1327858005.git.luto@amacapital.net> (raw)
In-Reply-To: <cover.1327858005.git.luto@amacapital.net>
In-Reply-To: <cover.1327858005.git.luto@amacapital.net>

They are normally disallowed because they could be used to subvert
setuid programs.  But if setuid is disabled, then they are safe.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 kernel/nsproxy.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b576f7f..47cf873 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -191,7 +191,13 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
 			       CLONE_NEWNET)))
 		return 0;
 
-	if (!capable(CAP_SYS_ADMIN))
+	/* We require either no_new_privs or CAP_SYS_ADMIN for all modes */
+	if (!current->no_new_privs && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/* NEWNS and NEWNET always require CAP_SYS_ADMIN. */
+	if ((unshare_flags & (CLONE_NEWNS | CLONE_NEWNET)) &&
+	    !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
 	*new_nsp = create_new_namespaces(unshare_flags, current,
-- 
1.7.7.6


  parent reply	other threads:[~2012-01-30 16:18 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 ` Andy Lutomirski [this message]
2012-02-01 19:02   ` [PATCH v3 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs 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
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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