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Message-Id: <1359711783-4379-5-git-send-email-tparkin@katalix.com>
Date: Fri, 1 Feb 2013 09:43:03 +0000
From: Tom Parkin <tparkin@...alix.com>
To: netdev@...r.kernel.org
Cc: jchapman@...alix.com, celston@...alix.com,
Tom Parkin <tparkin@...alix.com>
Subject: [PATCH 4/4] l2tp: create tunnel sockets in the right namespace
When creating unmanaged tunnel sockets we should honour the network namespace
passed to l2tp_tunnel_create. Furthermore, unmanaged tunnel sockets should
not hold a reference to the network namespace lest they accidentally keep
alive a namespace which should otherwise have been released.
Unmanaged tunnel sockets now drop their namespace reference via sk_change_net,
and are released in a new pernet exit callback, l2tp_exit_net.
Signed-off-by: Tom Parkin <tparkin@...alix.com>
Signed-off-by: James Chapman <jchapman@...alix.com>
---
net/l2tp/l2tp_core.c | 87 +++++++++++++++++++++++++++++++-------------------
1 file changed, 54 insertions(+), 33 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 60a498a..b6ba65f 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1409,18 +1409,18 @@ static void l2tp_tunnel_del_work(struct work_struct *work)
sock = sk->sk_socket;
BUG_ON(!sock);
- /* Force the tunnel socket to close. This will eventually
- * cause the tunnel to be deleted via the normal socket close
- * mechanisms when userspace closes the tunnel socket.
+ /* If the tunnel socket was created directly by the kernel, use the
+ * sk_* API to release the socket now. Otherwise go through the
+ * inet_* layer to shut the socket down, and let userspace close it.
+ * In either case the tunnel resources are freed in the socket
+ * destructor when the tunnel socket goes away.
*/
- inet_shutdown(sock, 2);
-
- /* If the tunnel's socket was created by the kernel,
- * close the socket here since the socket was not
- * created by userspace.
- */
- if (sock->file == NULL)
- inet_release(sock);
+ if (sock->file == NULL) {
+ kernel_sock_shutdown(sock, SHUT_RDWR);
+ sk_release_kernel(sk);
+ } else {
+ inet_shutdown(sock, 2);
+ }
l2tp_tunnel_sock_put(sk);
}
@@ -1428,29 +1428,37 @@ static void l2tp_tunnel_del_work(struct work_struct *work)
/* Create a socket for the tunnel, if one isn't set up by
* userspace. This is used for static tunnels where there is no
* managing L2TP daemon.
+ *
+ * Since we don't want these sockets to keep a namespace alive by
+ * themselves, we drop the socket's namespace refcount after creation.
+ * These sockets are freed when the namespace exits using the pernet
+ * exit hook.
*/
-static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
+static int l2tp_tunnel_sock_create(struct net *net,
+ u32 tunnel_id,
+ u32 peer_tunnel_id,
+ struct l2tp_tunnel_cfg *cfg,
+ struct socket **sockp)
{
int err = -EINVAL;
- struct sockaddr_in udp_addr;
+ struct socket *sock = NULL;
+ struct sockaddr_in udp_addr = {0};
+ struct sockaddr_l2tpip ip_addr = {0};
#if IS_ENABLED(CONFIG_IPV6)
- struct sockaddr_in6 udp6_addr;
- struct sockaddr_l2tpip6 ip6_addr;
+ struct sockaddr_in6 udp6_addr = {0};
+ struct sockaddr_l2tpip6 ip6_addr = {0};
#endif
- struct sockaddr_l2tpip ip_addr;
- struct socket *sock = NULL;
switch (cfg->encap) {
case L2TP_ENCAPTYPE_UDP:
#if IS_ENABLED(CONFIG_IPV6)
if (cfg->local_ip6 && cfg->peer_ip6) {
- err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
+ err = sock_create_kern(AF_INET6, SOCK_DGRAM, 0, &sock);
if (err < 0)
goto out;
- sock = *sockp;
+ sk_change_net(sock->sk, net);
- memset(&udp6_addr, 0, sizeof(udp6_addr));
udp6_addr.sin6_family = AF_INET6;
memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
sizeof(udp6_addr.sin6_addr));
@@ -1472,13 +1480,12 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
} else
#endif
{
- err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
+ err = sock_create_kern(AF_INET, SOCK_DGRAM, 0, &sock);
if (err < 0)
goto out;
- sock = *sockp;
+ sk_change_net(sock->sk, net);
- memset(&udp_addr, 0, sizeof(udp_addr));
udp_addr.sin_family = AF_INET;
udp_addr.sin_addr = cfg->local_ip;
udp_addr.sin_port = htons(cfg->local_udp_port);
@@ -1505,14 +1512,13 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
case L2TP_ENCAPTYPE_IP:
#if IS_ENABLED(CONFIG_IPV6)
if (cfg->local_ip6 && cfg->peer_ip6) {
- err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
- sockp);
+ err = sock_create_kern(AF_INET6, SOCK_DGRAM,
+ IPPROTO_L2TP, &sock);
if (err < 0)
goto out;
- sock = *sockp;
+ sk_change_net(sock->sk, net);
- memset(&ip6_addr, 0, sizeof(ip6_addr));
ip6_addr.l2tp_family = AF_INET6;
memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
sizeof(ip6_addr.l2tp_addr));
@@ -1534,14 +1540,13 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
} else
#endif
{
- err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
- sockp);
+ err = sock_create_kern(AF_INET, SOCK_DGRAM,
+ IPPROTO_L2TP, &sock);
if (err < 0)
goto out;
- sock = *sockp;
+ sk_change_net(sock->sk, net);
- memset(&ip_addr, 0, sizeof(ip_addr));
ip_addr.l2tp_family = AF_INET;
ip_addr.l2tp_addr = cfg->local_ip;
ip_addr.l2tp_conn_id = tunnel_id;
@@ -1565,8 +1570,10 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
}
out:
+ *sockp = sock;
if ((err < 0) && sock) {
- sock_release(sock);
+ kernel_sock_shutdown(sock, SHUT_RDWR);
+ sk_release_kernel(sock->sk);
*sockp = NULL;
}
@@ -1589,7 +1596,8 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
* kernel socket.
*/
if (fd < 0) {
- err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
+ err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
+ cfg, &sock);
if (err < 0)
goto err;
} else {
@@ -1909,8 +1917,21 @@ static __net_init int l2tp_init_net(struct net *net)
return 0;
}
+static __net_exit void l2tp_exit_net(struct net *net)
+{
+ struct l2tp_net *pn = l2tp_pernet(net);
+ struct l2tp_tunnel *tunnel = NULL;
+
+ rcu_read_lock_bh();
+ list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
+ (void)l2tp_tunnel_delete(tunnel);
+ }
+ rcu_read_unlock_bh();
+}
+
static struct pernet_operations l2tp_net_ops = {
.init = l2tp_init_net,
+ .exit = l2tp_exit_net,
.id = &l2tp_net_id,
.size = sizeof(struct l2tp_net),
};
--
1.7.9.5
--
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