From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41418 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752169AbdJSNIG (ORCPT ); Thu, 19 Oct 2017 09:08:06 -0400 Subject: Patch "packet: in packet_do_bind, test fanout with bind_lock held" has been added to the 3.18-stable tree To: willemb@google.com, davem@davemloft.net, edumazet@google.com, gregkh@linuxfoundation.org Cc: , From: Date: Thu, 19 Oct 2017 15:08:01 +0200 Message-ID: <150841848164126@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled packet: in packet_do_bind, test fanout with bind_lock held 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: packet-in-packet_do_bind-test-fanout-with-bind_lock-held.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 know about it. >>From foo@baz Thu Oct 19 14:44:13 CEST 2017 From: Willem de Bruijn Date: Tue, 26 Sep 2017 12:19:37 -0400 Subject: packet: in packet_do_bind, test fanout with bind_lock held From: Willem de Bruijn [ Upstream commit 4971613c1639d8e5f102c4e797c3bf8f83a5a69e ] Once a socket has po->fanout set, it remains a member of the group until it is destroyed. The prot_hook must be constant and identical across sockets in the group. If fanout_add races with packet_do_bind between the test of po->fanout and taking the lock, the bind call may make type or dev inconsistent with that of the fanout group. Hold po->bind_lock when testing po->fanout to avoid this race. I had to introduce artificial delay (local_bh_enable) to actually observe the race. Fixes: dc99f600698d ("packet: Add fanout support.") Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2662,13 +2662,15 @@ static int packet_do_bind(struct sock *s int ret = 0; bool unlisted = false; - if (po->fanout) - return -EINVAL; - lock_sock(sk); spin_lock(&po->bind_lock); rcu_read_lock(); + if (po->fanout) { + ret = -EINVAL; + goto out_unlock; + } + if (name) { dev = dev_get_by_name_rcu(sock_net(sk), name); if (!dev) { Patches currently in stable-queue which might be from willemb@google.com are queue-3.18/packet-in-packet_do_bind-test-fanout-with-bind_lock-held.patch queue-3.18/packet-hold-bind-lock-when-rebinding-to-fanout-hook.patch