From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Zhou , Jesse Gross , Thomas Graf , "David S. Miller" Subject: [PATCH 3.18 006/183] geneve: Fix races between socket add and release. Date: Sun, 25 Jan 2015 10:05:28 -0800 Message-Id: <20150125180810.467308724@linuxfoundation.org> In-Reply-To: <20150125180810.160428929@linuxfoundation.org> References: <20150125180810.160428929@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jesse Gross [ Upstream commit 12069401d895ff84076a50189ca842c0696b84b2 ] Currently, searching for a socket to add a reference to is not synchronized with deletion of sockets. This can result in use after free if there is another operation that is removing a socket at the same time. Solving this requires both holding the appropriate lock and checking the refcount to ensure that it has not already hit zero. Inspired by a related (but not exactly the same) issue in the VXLAN driver. Fixes: 0b5e8b8e ("net: Add Geneve tunneling protocol driver") CC: Andy Zhou Signed-off-by: Jesse Gross Acked-by: Thomas Graf Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/geneve.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/net/ipv4/geneve.c +++ b/net/ipv4/geneve.c @@ -302,6 +302,7 @@ struct geneve_sock *geneve_sock_add(stru geneve_rcv_t *rcv, void *data, bool no_share, bool ipv6) { + struct geneve_net *gn = net_generic(net, geneve_net_id); struct geneve_sock *gs; gs = geneve_socket_create(net, port, rcv, data, ipv6); @@ -311,15 +312,15 @@ struct geneve_sock *geneve_sock_add(stru if (no_share) /* Return error if sharing is not allowed. */ return ERR_PTR(-EINVAL); + spin_lock(&gn->sock_lock); gs = geneve_find_sock(net, port); - if (gs) { - if (gs->rcv == rcv) - atomic_inc(&gs->refcnt); - else + if (gs && ((gs->rcv != rcv) || + !atomic_add_unless(&gs->refcnt, 1, 0))) gs = ERR_PTR(-EBUSY); - } else { + spin_unlock(&gn->sock_lock); + + if (!gs) gs = ERR_PTR(-EINVAL); - } return gs; }