Re: netlink: NULL timer crash

[Eric Dumazet]

On Thu, 2017-03-23 at 07:53 -0700, Eric Dumazet wrote:

> Nice !
> 
> Looks like neigh->ops->solicit is NULL

Apparently we allow admins to do really stupid things with neighbours
on tunnels.

Following patch should avoid the crash.

Anyone has better ideas ?


 net/ipv4/arp.c   |    5 +++++
 net/ipv6/ndisc.c |    4 ++++
 2 files changed, 9 insertions(+)

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 
51b27ae09fbd725bcd8030982e5850215ac4ce5c..963191b12e28041bf5df6f37f222a7155f83a414
 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -146,8 +146,13 @@ static const struct neigh_ops arp_hh_ops = {
        .connected_output =     neigh_resolve_output,
 };
 
+static void arp_no_solicit(struct neighbour *neigh, struct sk_buff *skb)
+{
+}
+
 static const struct neigh_ops arp_direct_ops = {
        .family =               AF_INET,
+       .solicit =              arp_no_solicit,
        .output =               neigh_direct_output,
        .connected_output =     neigh_direct_output,
 };
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 
7ebac630d3c603186be2fc0dcbaac7d7e74bfde6..86f290b749d5ca0db4310b17ebeff35d847540c7
 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -99,9 +99,13 @@ static const struct neigh_ops ndisc_hh_ops = {
        .connected_output =     neigh_resolve_output,
 };
 
+static void ndisc_no_solicit(struct neighbour *neigh, struct sk_buff *skb)
+{
+}
 
 static const struct neigh_ops ndisc_direct_ops = {
        .family =               AF_INET6,
+       .solicit =              ndisc_no_solicit,
        .output =               neigh_direct_output,
        .connected_output =     neigh_direct_output,
 };