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Commit 48481c8f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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net: neigh: guard against NULL solicit() method 



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: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f35ec35e

net/core/neighbour.c

+2 −1
Original line number Diff line number Diff line
@@ -860,6 +860,7 @@ static void neigh_probe(struct neighbour *neigh) 
	if (skb)

		skb = skb_clone(skb, GFP_ATOMIC);

	write_unlock(&neigh->lock);

	if (neigh->ops->solicit)

		neigh->ops->solicit(neigh, skb);

	atomic_inc(&neigh->probes);

	kfree_skb(skb);