From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932131AbdKOCtk (ORCPT ); Tue, 14 Nov 2017 21:49:40 -0500 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:26737 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756173AbdKOCri (ORCPT ); Tue, 14 Nov 2017 21:47:38 -0500 From: alexander.levin@verizon.com Cc: David Ahern , "David S . Miller" , alexander.levin@verizon.com X-Host: endeavour.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.4 05/28] net: Allow IP_MULTICAST_IF to set index to L3 slave Thread-Topic: [PATCH AUTOSEL for 4.4 05/28] net: Allow IP_MULTICAST_IF to set index to L3 slave Thread-Index: AQHTXbveB+9ONFhfMEaDJ+b0H18JrA== Date: Wed, 15 Nov 2017 02:45:59 +0000 Message-ID: <20171115024551.5988-5-alexander.levin@verizon.com> References: <20171115024551.5988-1-alexander.levin@verizon.com> In-Reply-To: <20171115024551.5988-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAF2nlnu029396 From: David Ahern [ Upstream commit 7bb387c5ab12aeac3d5eea28686489ff46b53ca9 ] IP_MULTICAST_IF fails if sk_bound_dev_if is already set and the new index does not match it. e.g., ntpd[15381]: setsockopt IP_MULTICAST_IF 192.168.1.23 fails: Invalid argument Relax the check in setsockopt to allow setting mc_index to an L3 slave if sk_bound_dev_if points to an L3 master. Make a similar change for IPv6. In this case change the device lookup to take the rcu_read_lock avoiding a refcnt. The rcu lock is also needed for the lookup of a potential L3 master device. This really only silences a setsockopt failure since uses of mc_index are secondary to sk_bound_dev_if if it is set. In both cases, if either index is an L3 slave or master, lookups are directed to the same FIB table so relaxing the check at setsockopt time causes no harm. Patch is based on a suggested change by Darwin for a problem noted in their code base. Suggested-by: Darwin Dingel Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/ip_sockglue.c | 7 ++++++- net/ipv6/ipv6_sockglue.c | 16 ++++++++++++---- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index f300d1cbfa91..097a1243c16c 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -808,6 +808,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, { struct ip_mreqn mreq; struct net_device *dev = NULL; + int midx; if (sk->sk_type == SOCK_STREAM) goto e_inval; @@ -852,11 +853,15 @@ static int do_ip_setsockopt(struct sock *sk, int level, err = -EADDRNOTAVAIL; if (!dev) break; + + midx = l3mdev_master_ifindex(dev); + dev_put(dev); err = -EINVAL; if (sk->sk_bound_dev_if && - mreq.imr_ifindex != sk->sk_bound_dev_if) + mreq.imr_ifindex != sk->sk_bound_dev_if && + (!midx || midx != sk->sk_bound_dev_if)) break; inet->mc_index = mreq.imr_ifindex; diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 4449ad1f8114..a4a30d2ca66f 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -583,16 +583,24 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, if (val) { struct net_device *dev; + int midx; - if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != val) - goto e_inval; + rcu_read_lock(); - dev = dev_get_by_index(net, val); + dev = dev_get_by_index_rcu(net, val); if (!dev) { + rcu_read_unlock(); retv = -ENODEV; break; } - dev_put(dev); + midx = l3mdev_master_ifindex_rcu(dev); + + rcu_read_unlock(); + + if (sk->sk_bound_dev_if && + sk->sk_bound_dev_if != val && + (!midx || midx != sk->sk_bound_dev_if)) + goto e_inval; } np->mcast_oif = val; retv = 0; -- 2.11.0