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authorEric Dumazet <edumazet@google.com>2017-03-23 22:39:21 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-24 07:28:13 +0300
commit48481c8fa16410ffa45939b13b6c53c2ca609e5f (patch)
treef5cfccdad2c1fec0ac88053fd1e8299c0b7dc44b /net/core
parentf35ec35e5e726e7137deaee0dec24f8cbf07a48f (diff)
downloadlinux-48481c8fa16410ffa45939b13b6c53c2ca609e5f.tar.xz
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>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/neighbour.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index e7c12caa20c8..4526cbd7e28a 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -860,7 +860,8 @@ static void neigh_probe(struct neighbour *neigh)
if (skb)
skb = skb_clone(skb, GFP_ATOMIC);
write_unlock(&neigh->lock);
- neigh->ops->solicit(neigh, skb);
+ if (neigh->ops->solicit)
+ neigh->ops->solicit(neigh, skb);
atomic_inc(&neigh->probes);
kfree_skb(skb);
}