[PATCH 4.4 18/43] net: neigh: guard against NULL solicit() method
From: Greg Kroah-Hartman
Date: Mon May 01 2017 - 18:05:46 EST
4.4-stable review patch. If anyone has any objections, please let me know.
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 48481c8fa16410ffa45939b13b6c53c2ca609e5f ]
Dmitry posted a nice reproducer of a bug triggering in neigh_probe()
when dereferencing a NULL neigh->ops->solicit method.
This can happen for arp_direct_ops/ndisc_direct_ops and similar,
which can be used for NUD_NOARP neighbours (created when dev->header_ops
is NULL). Admin can then force changing nud_state to some other state
that would fire neigh timer.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/core/neighbour.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
@@ -859,7 +859,8 @@ static void neigh_probe(struct neighbour
skb = skb_clone(skb, GFP_ATOMIC);
- neigh->ops->solicit(neigh, skb);
+ if (neigh->ops->solicit)
+ neigh->ops->solicit(neigh, skb);