1 files changed, 78 insertions, 23 deletions

diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index 04c7e5b407fd..70cfdb46aa27 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -240,12 +240,15 @@ static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
         if (sk == NULL)
                 return NULL;
 
+        sock_hold(sk);
         session = (struct pppol2tp_session *)(sk->sk_user_data);
-        if (session == NULL)
-                return NULL;
+        if (session == NULL) {
+                sock_put(sk);
+                goto out;
+        }
 
         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
-
+out:
         return session;
 }
 
@@ -256,12 +259,15 @@ static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
         if (sk == NULL)
                 return NULL;
 
+        sock_hold(sk);
         tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
-        if (tunnel == NULL)
-                return NULL;
+        if (tunnel == NULL) {
+                sock_put(sk);
+                goto out;
+        }
 
         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
-
+out:
         return tunnel;
 }
 
@@ -716,12 +722,14 @@ discard:
         session->stats.rx_errors++;
         kfree_skb(skb);
         sock_put(session->sock);
+        sock_put(sock);
 
         return 0;
 
 error:
         /* Put UDP header back */
         __skb_push(skb, sizeof(struct udphdr));
+        sock_put(sock);
 
 no_tunnel:
         return 1;
@@ -745,10 +753,13 @@ static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
                "%s: received %d bytes\n", tunnel->name, skb->len);
 
         if (pppol2tp_recv_core(sk, skb))
-                goto pass_up;
+                goto pass_up_put;
 
+        sock_put(sk);
         return 0;
 
+pass_up_put:
+        sock_put(sk);
 pass_up:
         return 1;
 }
@@ -858,7 +869,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
 
         tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
         if (tunnel == NULL)
-                goto error;
+                goto error_put_sess;
 
         /* What header length is configured for this session? */
         hdr_len = pppol2tp_l2tp_header_len(session);
@@ -870,7 +881,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
                            sizeof(ppph) + total_len,
                            0, GFP_KERNEL);
         if (!skb)
-                goto error;
+                goto error_put_sess_tun;
 
         /* Reserve space for headers. */
         skb_reserve(skb, NET_SKB_PAD);
@@ -900,7 +911,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
         if (error < 0) {
                 kfree_skb(skb);
-                goto error;
+                goto error_put_sess_tun;
         }
         skb_put(skb, total_len);
 
@@ -947,10 +958,33 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
                 session->stats.tx_errors++;
         }
 
+        return error;
+
+error_put_sess_tun:
+        sock_put(session->tunnel_sock);
+error_put_sess:
+        sock_put(sk);
 error:
         return error;
 }
 
+/* Automatically called when the skb is freed.
+ */
+static void pppol2tp_sock_wfree(struct sk_buff *skb)
+{
+        sock_put(skb->sk);
+}
+
+/* For data skbs that we transmit, we associate with the tunnel socket
+ * but don't do accounting.
+ */
+static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
+{
+        sock_hold(sk);
+        skb->sk = sk;
+        skb->destructor = pppol2tp_sock_wfree;
+}
+
 /* Transmit function called by generic PPP driver.  Sends PPP frame
  * over PPPoL2TP socket.
  *
@@ -993,10 +1027,10 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 
         sk_tun = session->tunnel_sock;
         if (sk_tun == NULL)
-                goto abort;
+                goto abort_put_sess;
         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
         if (tunnel == NULL)
-                goto abort;
+                goto abort_put_sess;
 
         /* What header length is configured for this session? */
         hdr_len = pppol2tp_l2tp_header_len(session);
@@ -1009,7 +1043,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
         old_headroom = skb_headroom(skb);
         if (skb_cow_head(skb, headroom))
-                goto abort;
+                goto abort_put_sess_tun;
 
         new_headroom = skb_headroom(skb);
         skb_orphan(skb);
@@ -1069,7 +1103,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
         /* Get routing info from the tunnel socket */
         dst_release(skb->dst);
         skb->dst = dst_clone(__sk_dst_get(sk_tun));
-        skb->sk = sk_tun;
+        pppol2tp_skb_set_owner_w(skb, sk_tun);
 
         /* Queue the packet to IP for output */
         len = skb->len;
@@ -1086,8 +1120,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
                 session->stats.tx_errors++;
         }
 
+        sock_put(sk_tun);
+        sock_put(sk);
         return 1;
 
+abort_put_sess_tun:
+        sock_put(sk_tun);
+abort_put_sess:
+        sock_put(sk);
 abort:
         /* Free the original skb */
         kfree_skb(skb);
@@ -1191,7 +1231,7 @@ static void pppol2tp_tunnel_destruct(struct sock *sk)
 {
         struct pppol2tp_tunnel *tunnel;
 
-        tunnel = pppol2tp_sock_to_tunnel(sk);
+        tunnel = sk->sk_user_data;
         if (tunnel == NULL)
                 goto end;
 
@@ -1230,10 +1270,12 @@ static void pppol2tp_session_destruct(struct sock *sk)
         if (sk->sk_user_data != NULL) {
                 struct pppol2tp_tunnel *tunnel;
 
-                session = pppol2tp_sock_to_session(sk);
+                session = sk->sk_user_data;
                 if (session == NULL)
                         goto out;
 
+                BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+
                 /* Don't use pppol2tp_sock_to_tunnel() here to
                  * get the tunnel context because the tunnel
                  * socket might have already been closed (its
@@ -1611,7 +1653,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 
         error = ppp_register_channel(&po->chan);
         if (error)
-                goto end;
+                goto end_put_tun;
 
         /* This is how we get the session context from the socket. */
         sk->sk_user_data = session;
@@ -1631,6 +1673,8 @@ out_no_ppp:
         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
                "%s: created\n", session->name);
 
+end_put_tun:
+        sock_put(tunnel_sock);
 end:
         release_sock(sk);
 
@@ -1678,6 +1722,7 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
         *usockaddr_len = len;
 
         error = 0;
+        sock_put(sock->sk);
 
 end:
         return error;
@@ -1916,14 +1961,17 @@ static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
                 err = -EBADF;
                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
                 if (tunnel == NULL)
-                        goto end;
+                        goto end_put_sess;
 
                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
-                goto end;
+                sock_put(session->tunnel_sock);
+                goto end_put_sess;
         }
 
         err = pppol2tp_session_ioctl(session, cmd, arg);
 
+end_put_sess:
+        sock_put(sk);
 end:
         return err;
 }
@@ -2069,14 +2117,17 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
                 err = -EBADF;
                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
                 if (tunnel == NULL)
-                        goto end;
+                        goto end_put_sess;
 
                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
+                sock_put(session->tunnel_sock);
         } else
                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
 
         err = 0;
 
+end_put_sess:
+        sock_put(sk);
 end:
         return err;
 }
@@ -2191,20 +2242,24 @@ static int pppol2tp_getsockopt(struct socket *sock, int level,
                 err = -EBADF;
                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
                 if (tunnel == NULL)
-                        goto end;
+                        goto end_put_sess;
 
                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
+                sock_put(session->tunnel_sock);
         } else
                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
 
         err = -EFAULT;
         if (put_user(len, (int __user *) optlen))
-                goto end;
+                goto end_put_sess;
 
         if (copy_to_user((void __user *) optval, &val, len))
-                goto end;
+                goto end_put_sess;
 
         err = 0;
+
+end_put_sess:
+        sock_put(sk);
 end:
         return err;
 }