This is a note to let you know that I've just added the patch titled net: neigh: guard against NULL solicit() method to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-neigh-guard-against-null-solicit-method.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sun Apr 30 15:50:51 CEST 2017 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Thu, 23 Mar 2017 12:39:21 -0700 Subject: net: neigh: guard against NULL solicit() method From: Eric Dumazet <edumazet@xxxxxxxxxx> [ Upstream commit 48481c8fa16410ffa45939b13b6c53c2ca609e5f ] 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@xxxxxxxxxx> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/core/neighbour.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -875,7 +875,8 @@ static void neigh_probe(struct neighbour if (skb) skb = skb_copy(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); } Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are queue-3.18/net-packet-fix-overflow-in-check-for-tp_frame_nr.patch queue-3.18/net-packet-fix-overflow-in-check-for-tp_reserve.patch queue-3.18/net-neigh-guard-against-null-solicit-method.patch