4.16-stable review patch. If anyone has any objections, please let me know.
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From: Guillaume Nault g.nault@alphalink.fr
[ Upstream commit f6cd651b056ffd3b4e8496afd44d4ed44bf69136 ]
We can't use l2tp_tunnel_find() to prevent l2tp_nl_cmd_tunnel_create() from creating a duplicate tunnel. A tunnel can be concurrently registered after l2tp_tunnel_find() returns. Therefore, searching for duplicates must be done at registration time.
Finally, remove l2tp_tunnel_find() entirely as it isn't use anywhere anymore.
Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault g.nault@alphalink.fr Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/l2tp/l2tp_core.c | 35 ++++++++++++++--------------------- net/l2tp/l2tp_core.h | 1 - net/l2tp/l2tp_netlink.c | 6 ------ 3 files changed, 14 insertions(+), 28 deletions(-)
--- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -335,26 +335,6 @@ err_tlock: } EXPORT_SYMBOL_GPL(l2tp_session_register);
-/* Lookup a tunnel by id - */ -struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id) -{ - struct l2tp_tunnel *tunnel; - struct l2tp_net *pn = l2tp_pernet(net); - - rcu_read_lock_bh(); - list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { - if (tunnel->tunnel_id == tunnel_id) { - rcu_read_unlock_bh(); - return tunnel; - } - } - rcu_read_unlock_bh(); - - return NULL; -} -EXPORT_SYMBOL_GPL(l2tp_tunnel_find); - struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth) { struct l2tp_net *pn = l2tp_pernet(net); @@ -1501,6 +1481,7 @@ static int l2tp_validate_socket(const st int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, struct l2tp_tunnel_cfg *cfg) { + struct l2tp_tunnel *tunnel_walk; struct l2tp_net *pn; struct socket *sock; struct sock *sk; @@ -1529,7 +1510,16 @@ int l2tp_tunnel_register(struct l2tp_tun tunnel->l2tp_net = net;
pn = l2tp_pernet(net); + spin_lock_bh(&pn->l2tp_tunnel_list_lock); + list_for_each_entry(tunnel_walk, &pn->l2tp_tunnel_list, list) { + if (tunnel_walk->tunnel_id == tunnel->tunnel_id) { + spin_unlock_bh(&pn->l2tp_tunnel_list_lock); + + ret = -EEXIST; + goto err_sock; + } + } list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
@@ -1558,7 +1548,10 @@ int l2tp_tunnel_register(struct l2tp_tun return 0;
err_sock: - sockfd_put(sock); + if (tunnel->fd < 0) + sock_release(sock); + else + sockfd_put(sock); err: return ret; } --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -220,7 +220,6 @@ struct l2tp_session *l2tp_session_get(co struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, const char *ifname); -struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id); struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, --- a/net/l2tp/l2tp_netlink.c +++ b/net/l2tp/l2tp_netlink.c @@ -236,12 +236,6 @@ static int l2tp_nl_cmd_tunnel_create(str if (info->attrs[L2TP_ATTR_DEBUG]) cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
- tunnel = l2tp_tunnel_find(net, tunnel_id); - if (tunnel != NULL) { - ret = -EEXIST; - goto out; - } - ret = -EINVAL; switch (cfg.encap) { case L2TP_ENCAPTYPE_UDP: