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authorDavid Ahern <dsa@cumulusnetworks.com>2016-12-29 15:39:37 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-30 08:37:26 +0000
commitd7c3d5333e39a3089ad259222b767a965963a693 (patch)
treef6a8f275ad7e67ee7a1d380ee94189e0ebfc6aad
parent778395506a7f5744dce0cc14876c2f45ac779dea (diff)
net: Allow IP_MULTICAST_IF to set index to L3 slave
[ 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 <darwin.dingel@alliedtelesis.co.nz> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/ip_sockglue.c7
-rw-r--r--net/ipv6/ipv6_sockglue.c16
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 @@ done:
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;