Commit 48481c8f authored Mar 23, 2017 by Eric Dumazet Committed by David S. Miller Mar 23, 2017

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: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David 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);

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