From 22c74764aa2943ecdf9f07c900d8a9c8ba6c9265 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 6 Mar 2019 10:42:53 +0100 Subject: [PATCH] ipv4/route: fail early when inet dev is missing If a non local multicast packet reaches ip_route_input_rcu() while the ingress device IPv4 private data (in_dev) is NULL, we end up doing a NULL pointer dereference in IN_DEV_MFORWARD(). Since the later call to ip_route_input_mc() is going to fail if !in_dev, we can fail early in such scenario and avoid the dangerous code path. v1 -> v2: - clarified the commit message, no code changes Reported-by: Tianhao Zhao Fixes: e58e41596811 ("net: Enable support for VRF with ipv4 multicast") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/route.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 738ff0a1a0482a..8ca3642f0d9bcc 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2149,12 +2149,13 @@ int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, int our = 0; int err = -EINVAL; - if (in_dev) - our = ip_check_mc_rcu(in_dev, daddr, saddr, - ip_hdr(skb)->protocol); + if (!in_dev) + return err; + our = ip_check_mc_rcu(in_dev, daddr, saddr, + ip_hdr(skb)->protocol); /* check l3 master if no match yet */ - if ((!in_dev || !our) && netif_is_l3_slave(dev)) { + if (!our && netif_is_l3_slave(dev)) { struct in_device *l3_in_dev; l3_in_dev = __in_dev_get_rcu(skb->dev);