l2tp: hold tunnel in pppol2tp_connect()

[ Upstream commit f9e56baf03f9d36043a78f16e3e8b2cfd211e09e ]

Use l2tp_tunnel_get() in pppol2tp_connect() to ensure the tunnel isn't
going to disappear while processing the rest of the function.

Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
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>

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index e8ec4f3e54fb3bb2e1aaf1b56a7f40f42a3c42a3..412c513d69b3c84838de2394e4f059dec1953558 100644 (file)
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -584,6 +584,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
        u32 tunnel_id, peer_tunnel_id;
        u32 session_id, peer_session_id;
        bool drop_refcnt = false;
+       bool drop_tunnel = false;
        int ver = 2;
        int fd;
 
@@ -652,7 +653,9 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
        if (tunnel_id == 0)
                goto end;
 
-       tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
+       tunnel = l2tp_tunnel_get(sock_net(sk), tunnel_id);
+       if (tunnel)
+               drop_tunnel = true;
 
        /* Special case: create tunnel context if session_id and
         * peer_session_id is 0. Otherwise look up tunnel using supplied
@@ -781,6 +784,8 @@ out_no_ppp:
 end:
        if (drop_refcnt)
                l2tp_session_dec_refcount(session);
+       if (drop_tunnel)
+               l2tp_tunnel_dec_refcount(tunnel);
        release_sock(sk);
 
        return error;