4.19-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 22c74764aa2943ecdf9f07c900d8a9c8ba6c9265 ]
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 tizhao@redhat.com Fixes: e58e41596811 ("net: Enable support for VRF with ipv4 multicast") Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: David Ahern dsahern@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/route.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2155,12 +2155,13 @@ int ip_route_input_rcu(struct sk_buff *s 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);