Commit 48481c8f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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
...@@ -860,7 +860,8 @@ static void neigh_probe(struct neighbour *neigh) ...@@ -860,7 +860,8 @@ static void neigh_probe(struct neighbour *neigh)
if (skb) if (skb)
skb = skb_clone(skb, GFP_ATOMIC); skb = skb_clone(skb, GFP_ATOMIC);
write_unlock(&neigh->lock); write_unlock(&neigh->lock);
neigh->ops->solicit(neigh, skb); if (neigh->ops->solicit)
neigh->ops->solicit(neigh, skb);
atomic_inc(&neigh->probes); atomic_inc(&neigh->probes);
kfree_skb(skb); kfree_skb(skb);
} }
......
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