From 167eb17e0b178549f5e19036b16b6d6e35856b67 Mon Sep 17 00:00:00 2001 From: Tom Parkin Date: Thu, 31 Jan 2013 23:43:03 +0000 Subject: [PATCH] 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 Signed-off-by: James Chapman Signed-off-by: David S. Miller --- 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 60a498a459dd..b6ba65fa3c50 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), }; -- GitLab