From patchwork Thu Aug 13 13:44:51 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Paris X-Patchwork-Id: 31297 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@bilbo.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 15FD4B6EDF for ; Thu, 13 Aug 2009 23:47:51 +1000 (EST) Received: by ozlabs.org (Postfix) id 09862DDD1B; Thu, 13 Aug 2009 23:47:51 +1000 (EST) Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 85759DDD0B for ; Thu, 13 Aug 2009 23:47:50 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754567AbZHMNp5 (ORCPT ); Thu, 13 Aug 2009 09:45:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754551AbZHMNp5 (ORCPT ); Thu, 13 Aug 2009 09:45:57 -0400 Received: from mx2.redhat.com ([66.187.237.31]:49718 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753926AbZHMNp4 (ORCPT ); Thu, 13 Aug 2009 09:45:56 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n7DDitxY020881; Thu, 13 Aug 2009 09:44:55 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n7DDiqQ4022730; Thu, 13 Aug 2009 09:44:52 -0400 Received: from paris.rdu.redhat.com (paris.rdu.redhat.com [10.11.231.241]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n7DDip9u010647; Thu, 13 Aug 2009 09:44:52 -0400 From: Eric Paris Subject: [PATCH 1/3] Networking: use CAP_NET_ADMIN when deciding to call request_module To: linux-kernel@vger.kernel.org, selinux@tycho.nsa.gov, netdev@vger.kernel.org, linux-security-module@vger.kernel.org Cc: sds@tycho.nsa.gov, davem@davemloft.net, shemminger@linux-foundation.org, kees@ubuntu.com, morgan@kernel.org, casey@schaufler-ca.com, dwalsh@redhat.com Date: Thu, 13 Aug 2009 09:44:51 -0400 Message-ID: <20090813134451.29186.41664.stgit@paris.rdu.redhat.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The networking code checks CAP_SYS_MODULE before using request_module() to try to load a kernel module. While this seems reasonable it's actually weakening system security since we have to allow CAP_SYS_MODULE for things like /sbin/ip and bluetoothd which need to be able to trigger module loads. CAP_SYS_MODULE actually grants those binaries the ability to directly load any code into the kernel. We should instead be protecting modprobe and the modules on disk, rather than granting random programs the ability to load code directly into the kernel. Instead we are going to gate those networking checks on CAP_NET_ADMIN which still limits them to root but which does not grant those processes the ability to load arbitrary code into the kernel. Signed-off-by: Eric Paris Acked-by: Serge Hallyn Acked-by: Paul Moore Acked-by: David S. Miller --- drivers/staging/comedi/comedi_fops.c | 8 ++++---- net/core/dev.c | 2 +- net/ipv4/tcp_cong.c | 4 ++-- 3 files changed, 7 insertions(+), 7 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 42e4bc4..f54bb9b 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1772,12 +1772,12 @@ static int comedi_open(struct inode *inode, struct file *file) mutex_lock(&dev->mutex); if (dev->attached) goto ok; - if (!capable(CAP_SYS_MODULE) && dev->in_request_module) { + if (!capable(CAP_NET_ADMIN) && dev->in_request_module) { DPRINTK("in request module\n"); mutex_unlock(&dev->mutex); return -ENODEV; } - if (capable(CAP_SYS_MODULE) && dev->in_request_module) + if (capable(CAP_NET_ADMIN) && dev->in_request_module) goto ok; dev->in_request_module = 1; @@ -1790,8 +1790,8 @@ static int comedi_open(struct inode *inode, struct file *file) dev->in_request_module = 0; - if (!dev->attached && !capable(CAP_SYS_MODULE)) { - DPRINTK("not attached and not CAP_SYS_MODULE\n"); + if (!dev->attached && !capable(CAP_NET_ADMIN)) { + DPRINTK("not attached and not CAP_NET_ADMIN\n"); mutex_unlock(&dev->mutex); return -ENODEV; } diff --git a/net/core/dev.c b/net/core/dev.c index 09fb03f..2604db9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1031,7 +1031,7 @@ void dev_load(struct net *net, const char *name) dev = __dev_get_by_name(net, name); read_unlock(&dev_base_lock); - if (!dev && capable(CAP_SYS_MODULE)) + if (!dev && capable(CAP_NET_ADMIN)) request_module("%s", name); } diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index e92beb9..6428b34 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -116,7 +116,7 @@ int tcp_set_default_congestion_control(const char *name) spin_lock(&tcp_cong_list_lock); ca = tcp_ca_find(name); #ifdef CONFIG_MODULES - if (!ca && capable(CAP_SYS_MODULE)) { + if (!ca && capable(CAP_NET_ADMIN)) { spin_unlock(&tcp_cong_list_lock); request_module("tcp_%s", name); @@ -246,7 +246,7 @@ int tcp_set_congestion_control(struct sock *sk, const char *name) #ifdef CONFIG_MODULES /* not found attempt to autoload module */ - if (!ca && capable(CAP_SYS_MODULE)) { + if (!ca && capable(CAP_NET_ADMIN)) { rcu_read_unlock(); request_module("tcp_%s", name); rcu_read_lock();