net: neigh: guard against NULL solicit() method
authorEric Dumazet <edumazet@google.com>
Thu, 23 Mar 2017 19:39:21 +0000 (12:39 -0700)
committerDavid S. Miller <davem@davemloft.net>
Fri, 24 Mar 2017 04:28:13 +0000 (21:28 -0700)
commit48481c8fa16410ffa45939b13b6c53c2ca609e5f
treef5cfccdad2c1fec0ac88053fd1e8299c0b7dc44b
parentf35ec35e5e726e7137deaee0dec24f8cbf07a48f
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>
net/core/neighbour.c