X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=net%2Fl2tp%2Fl2tp_ppp.c;h=54e249e96e94eba49e0b4a6528c05cf9fcc4f566;hp=8a90d756c904cedec8e0757f68885715ff42e55a;hb=99f890a5f4de33ca43ea79b7b54241849e4bf904;hpb=81a3c10ce8a7fd5bf9a06bfc38bd417512911831 diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 8a90d756c904..54e249e96e94 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -95,6 +95,7 @@ #include #include #include +#include #include #include @@ -125,8 +126,11 @@ struct pppol2tp_session { int owner; /* pid that opened the socket */ - struct sock *sock; /* Pointer to the session + struct mutex sk_lock; /* Protects .sk */ + struct sock __rcu *sk; /* Pointer to the session * PPPoX socket */ + struct sock *__sk; /* Copy of .sk, for cleanup */ + struct rcu_head rcu; /* For asynchronous release */ struct sock *tunnel_sock; /* Pointer to the tunnel UDP * socket */ int flags; /* accessed by PPPIOCGFLAGS. @@ -141,6 +145,24 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = { static const struct proto_ops pppol2tp_ops; +/* Retrieves the pppol2tp socket associated to a session. + * A reference is held on the returned socket, so this function must be paired + * with sock_put(). + */ +static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session) +{ + struct pppol2tp_session *ps = l2tp_session_priv(session); + struct sock *sk; + + rcu_read_lock(); + sk = rcu_dereference(ps->sk); + if (sk) + sock_hold(sk); + rcu_read_unlock(); + + return sk; +} + /* Helpers to obtain tunnel/session contexts from sockets. */ static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk) @@ -200,8 +222,6 @@ static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock, if (sk->sk_state & PPPOX_BOUND) goto end; - msg->msg_namelen = 0; - err = 0; skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &err); @@ -230,7 +250,8 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int /* If the socket is bound, send it in to PPP's input queue. Otherwise * queue it on the session socket. */ - sk = ps->sock; + rcu_read_lock(); + sk = rcu_dereference(ps->sk); if (sk == NULL) goto no_sock; @@ -266,31 +287,17 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int session->stats.rx_errors++; kfree_skb(skb); } + rcu_read_unlock(); return; no_sock: + rcu_read_unlock(); PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO, "%s: no socket\n", session->name); kfree_skb(skb); } -static void pppol2tp_session_sock_hold(struct l2tp_session *session) -{ - struct pppol2tp_session *ps = l2tp_session_priv(session); - - if (ps->sock) - sock_hold(ps->sock); -} - -static void pppol2tp_session_sock_put(struct l2tp_session *session) -{ - struct pppol2tp_session *ps = l2tp_session_priv(session); - - if (ps->sock) - sock_put(ps->sock); -} - /************************************************************************ * Transmit handling ***********************************************************************/ @@ -350,18 +357,21 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh skb_put(skb, 2); /* Copy user data into skb */ - error = memcpy_fromiovec(skb->data, m->msg_iov, total_len); + error = memcpy_fromiovec(skb_put(skb, total_len), m->msg_iov, + total_len); if (error < 0) { kfree_skb(skb); goto error_put_sess_tun; } - skb_put(skb, total_len); + local_bh_disable(); l2tp_xmit_skb(session, skb, session->hdr_len); + local_bh_enable(); sock_put(ps->tunnel_sock); + sock_put(sk); - return error; + return total_len; error_put_sess_tun: sock_put(ps->tunnel_sock); @@ -431,7 +441,9 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb) skb->data[0] = ppph[0]; skb->data[1] = ppph[1]; + local_bh_disable(); l2tp_xmit_skb(session, skb, session->hdr_len); + local_bh_enable(); sock_put(sk_tun); sock_put(sk); @@ -455,37 +467,6 @@ abort: */ static void pppol2tp_session_close(struct l2tp_session *session) { - struct pppol2tp_session *ps = l2tp_session_priv(session); - struct sock *sk = ps->sock; - struct sk_buff *skb; - - BUG_ON(session->magic != L2TP_SESSION_MAGIC); - - if (session->session_id == 0) - goto out; - - if (sk != NULL) { - lock_sock(sk); - - if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) { - pppox_unbind_sock(sk); - sk->sk_state = PPPOX_DEAD; - sk->sk_state_change(sk); - } - - /* Purge any queued data */ - skb_queue_purge(&sk->sk_receive_queue); - skb_queue_purge(&sk->sk_write_queue); - while ((skb = skb_dequeue(&session->reorder_q))) { - kfree_skb(skb); - sock_put(sk); - } - - release_sock(sk); - } - -out: - return; } /* Really kill the session socket. (Called from sock_put() if @@ -509,6 +490,14 @@ out: return; } +static void pppol2tp_put_sk(struct rcu_head *head) +{ + struct pppol2tp_session *ps; + + ps = container_of(head, typeof(*ps), rcu); + sock_put(ps->__sk); +} + /* Called when the PPPoX socket (session) is closed. */ static int pppol2tp_release(struct socket *sock) @@ -534,17 +523,26 @@ static int pppol2tp_release(struct socket *sock) session = pppol2tp_sock_to_session(sk); - /* Purge any queued data */ - skb_queue_purge(&sk->sk_receive_queue); - skb_queue_purge(&sk->sk_write_queue); if (session != NULL) { - struct sk_buff *skb; - while ((skb = skb_dequeue(&session->reorder_q))) { - kfree_skb(skb); - sock_put(sk); - } - sock_put(sk); + struct pppol2tp_session *ps; + + l2tp_session_delete(session); + + ps = l2tp_session_priv(session); + mutex_lock(&ps->sk_lock); + ps->__sk = rcu_dereference_protected(ps->sk, + lockdep_is_held(&ps->sk_lock)); + RCU_INIT_POINTER(ps->sk, NULL); + mutex_unlock(&ps->sk_lock); + call_rcu(&ps->rcu, pppol2tp_put_sk); + + /* Rely on the sock_put() call at the end of the function for + * dropping the reference held by pppol2tp_sock_to_session(). + * The last reference will be dropped by pppol2tp_put_sk(). + */ } + skb_queue_purge(&sk->sk_receive_queue); + skb_queue_purge(&sk->sk_write_queue); release_sock(sk); @@ -611,16 +609,47 @@ out: static void pppol2tp_show(struct seq_file *m, void *arg) { struct l2tp_session *session = arg; - struct pppol2tp_session *ps = l2tp_session_priv(session); + struct sock *sk; + + sk = pppol2tp_session_get_sock(session); + if (sk) { + struct pppox_sock *po = pppox_sk(sk); - if (ps) { - struct pppox_sock *po = pppox_sk(ps->sock); - if (po) - seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan)); + seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan)); + sock_put(sk); } } #endif +static void pppol2tp_session_init(struct l2tp_session *session) +{ + struct pppol2tp_session *ps; + struct dst_entry *dst; + + session->recv_skb = pppol2tp_recv; + session->session_close = pppol2tp_session_close; +#if IS_ENABLED(CONFIG_L2TP_DEBUGFS) + session->show = pppol2tp_show; +#endif + + ps = l2tp_session_priv(session); + mutex_init(&ps->sk_lock); + ps->tunnel_sock = session->tunnel->sock; + ps->owner = current->pid; + + /* If PMTU discovery was enabled, use the MTU that was discovered */ + dst = sk_dst_get(session->tunnel->sock); + if (dst) { + u32 pmtu = dst_mtu(dst); + + if (pmtu) { + session->mtu = pmtu - PPPOL2TP_HEADER_OVERHEAD; + session->mru = pmtu - PPPOL2TP_HEADER_OVERHEAD; + } + dst_release(dst); + } +} + /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket */ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, @@ -633,11 +662,12 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, struct l2tp_session *session = NULL; struct l2tp_tunnel *tunnel; struct pppol2tp_session *ps; - struct dst_entry *dst; struct l2tp_session_cfg cfg = { 0, }; int error = 0; 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; @@ -681,7 +711,9 @@ 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 @@ -718,64 +750,53 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, tunnel->peer_tunnel_id = sp3->pppol2tp.d_tunnel; } - /* Create session if it doesn't already exist. We handle the - * case where a session was previously created by the netlink - * interface by checking that the session doesn't already have - * a socket and its tunnel socket are what we expect. If any - * of those checks fail, return EEXIST to the caller. - */ - session = l2tp_session_find(sock_net(sk), tunnel, session_id); - if (session == NULL) { - /* Default MTU must allow space for UDP/L2TP/PPP - * headers. + session = l2tp_session_get(sock_net(sk), tunnel, session_id, false); + if (session) { + drop_refcnt = true; + ps = l2tp_session_priv(session); + + /* Using a pre-existing session is fine as long as it hasn't + * been connected yet. */ - cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD; + mutex_lock(&ps->sk_lock); + if (rcu_dereference_protected(ps->sk, + lockdep_is_held(&ps->sk_lock))) { + mutex_unlock(&ps->sk_lock); + error = -EEXIST; + goto end; + } + + /* consistency checks */ + if (ps->tunnel_sock != tunnel->sock) { + mutex_unlock(&ps->sk_lock); + error = -EEXIST; + goto end; + } + } else { + /* Default MTU must allow space for UDP/L2TP/PPP headers */ + cfg.mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD; + cfg.mru = cfg.mtu; - /* Allocate and initialize a new session context. */ session = l2tp_session_create(sizeof(struct pppol2tp_session), tunnel, session_id, peer_session_id, &cfg); - if (session == NULL) { - error = -ENOMEM; + if (IS_ERR(session)) { + error = PTR_ERR(session); goto end; } - } else { + + pppol2tp_session_init(session); ps = l2tp_session_priv(session); - error = -EEXIST; - if (ps->sock != NULL) - goto end; + l2tp_session_inc_refcount(session); - /* consistency checks */ - if (ps->tunnel_sock != tunnel->sock) + mutex_lock(&ps->sk_lock); + error = l2tp_session_register(session, tunnel); + if (error < 0) { + mutex_unlock(&ps->sk_lock); + kfree(session); goto end; - } - - /* Associate session with its PPPoL2TP socket */ - ps = l2tp_session_priv(session); - ps->owner = current->pid; - ps->sock = sk; - ps->tunnel_sock = tunnel->sock; - - session->recv_skb = pppol2tp_recv; - session->session_close = pppol2tp_session_close; -#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE) - session->show = pppol2tp_show; -#endif - - /* We need to know each time a skb is dropped from the reorder - * queue. - */ - session->ref = pppol2tp_session_sock_hold; - session->deref = pppol2tp_session_sock_put; - - /* If PMTU discovery was enabled, use the MTU that was discovered */ - dst = sk_dst_get(sk); - if (dst != NULL) { - u32 pmtu = dst_mtu(__sk_dst_get(sk)); - if (pmtu != 0) - session->mtu = session->mru = pmtu - - PPPOL2TP_HEADER_OVERHEAD; - dst_release(dst); + } + drop_refcnt = true; } /* Special case: if source & dest session_id == 0x0000, this @@ -800,17 +821,32 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, po->chan.mtu = session->mtu; error = ppp_register_net_channel(sock_net(sk), &po->chan); - if (error) + if (error) { + mutex_unlock(&ps->sk_lock); goto end; + } out_no_ppp: /* This is how we get the session context from the socket. */ sk->sk_user_data = session; + rcu_assign_pointer(ps->sk, sk); + mutex_unlock(&ps->sk_lock); + + /* Keep the reference we've grabbed on the session: sk doesn't expect + * the session to disappear. pppol2tp_session_destruct() is responsible + * for dropping it. + */ + drop_refcnt = false; + sk->sk_state = PPPOX_CONNECTED; PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, "%s: created\n", session->name); end: + if (drop_refcnt) + l2tp_session_dec_refcount(session); + if (drop_tunnel) + l2tp_tunnel_dec_refcount(tunnel); release_sock(sk); return error; @@ -818,31 +854,19 @@ end: #ifdef CONFIG_L2TP_V3 -/* Called when creating sessions via the netlink interface. - */ -static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) +/* Called when creating sessions via the netlink interface. */ +static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel, + u32 session_id, u32 peer_session_id, + struct l2tp_session_cfg *cfg) { int error; - struct l2tp_tunnel *tunnel; struct l2tp_session *session; - struct pppol2tp_session *ps; - - tunnel = l2tp_tunnel_find(net, tunnel_id); - - /* Error if we can't find the tunnel */ - error = -ENOENT; - if (tunnel == NULL) - goto out; /* Error if tunnel socket is not prepped */ - if (tunnel->sock == NULL) - goto out; - - /* Check that this session doesn't already exist */ - error = -EEXIST; - session = l2tp_session_find(net, tunnel, session_id); - if (session != NULL) - goto out; + if (!tunnel->sock) { + error = -ENOENT; + goto err; + } /* Default MTU values. */ if (cfg->mtu == 0) @@ -851,37 +875,28 @@ static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_i cfg->mru = cfg->mtu; /* Allocate and initialize a new session context. */ - error = -ENOMEM; session = l2tp_session_create(sizeof(struct pppol2tp_session), tunnel, session_id, peer_session_id, cfg); - if (session == NULL) - goto out; + if (IS_ERR(session)) { + error = PTR_ERR(session); + goto err; + } - ps = l2tp_session_priv(session); - ps->tunnel_sock = tunnel->sock; + pppol2tp_session_init(session); - PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, - "%s: created\n", session->name); + error = l2tp_session_register(session, tunnel); + if (error < 0) + goto err_sess; - error = 0; + return 0; -out: +err_sess: + kfree(session); +err: return error; } -/* Called when deleting sessions via the netlink interface. - */ -static int pppol2tp_session_delete(struct l2tp_session *session) -{ - struct pppol2tp_session *ps = l2tp_session_priv(session); - - if (ps->sock == NULL) - l2tp_session_dec_refcount(session); - - return 0; -} - #endif /* CONFIG_L2TP_V3 */ /* getname() support. @@ -910,12 +925,10 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr, pls = l2tp_session_priv(session); tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock); - if (tunnel == NULL) { - error = -EBADF; + if (tunnel == NULL) goto end_put_sess; - } - inet = inet_sk(sk); + inet = inet_sk(tunnel->sock); if (tunnel->version == 2) { struct sockaddr_pppol2tp sp; len = sizeof(sp); @@ -951,12 +964,11 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr, } *usockaddr_len = len; + error = 0; sock_put(pls->tunnel_sock); end_put_sess: sock_put(sk); - error = 0; - end: return error; } @@ -1002,8 +1014,9 @@ static int pppol2tp_session_ioctl(struct l2tp_session *session, "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n", session->name, cmd, arg); - sk = ps->sock; - sock_hold(sk); + sk = pppol2tp_session_get_sock(session); + if (!sk) + return -EBADR; switch (cmd) { case SIOCGIFMTU: @@ -1149,11 +1162,18 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel, if (stats.session_id != 0) { /* resend to session ioctl handler */ struct l2tp_session *session = - l2tp_session_find(sock_net(sk), tunnel, stats.session_id); - if (session != NULL) - err = pppol2tp_session_ioctl(session, cmd, arg); - else + l2tp_session_get(sock_net(sk), tunnel, + stats.session_id, true); + + if (session) { + err = pppol2tp_session_ioctl(session, cmd, + arg); + if (session->deref) + session->deref(session); + l2tp_session_dec_refcount(session); + } else { err = -EBADR; + } break; } #ifdef CONFIG_XFRM @@ -1273,7 +1293,6 @@ static int pppol2tp_session_setsockopt(struct sock *sk, int optname, int val) { int err = 0; - struct pppol2tp_session *ps = l2tp_session_priv(session); switch (optname) { case PPPOL2TP_SO_RECVSEQ: @@ -1293,8 +1312,8 @@ static int pppol2tp_session_setsockopt(struct sock *sk, } session->send_seq = val ? -1 : 0; { - struct sock *ssk = ps->sock; - struct pppox_sock *po = pppox_sk(ssk); + struct pppox_sock *po = pppox_sk(sk); + po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ : PPPOL2TP_L2TP_HDR_SIZE_NOSEQ; } @@ -1348,7 +1367,7 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname, int err; if (level != SOL_PPPOL2TP) - return udp_prot.setsockopt(sk, level, optname, optval, optlen); + return -EINVAL; if (optlen < sizeof(int)) return -EINVAL; @@ -1381,8 +1400,6 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname, } else err = pppol2tp_session_setsockopt(sk, session, optname, val); - err = 0; - end_put_sess: sock_put(sk); end: @@ -1474,7 +1491,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, struct pppol2tp_session *ps; if (level != SOL_PPPOL2TP) - return udp_prot.getsockopt(sk, level, optname, optval, optlen); + return -EINVAL; if (get_user(len, (int __user *) optlen)) return -EFAULT; @@ -1505,8 +1522,13 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val); sock_put(ps->tunnel_sock); - } else + if (err) + goto end_put_sess; + } else { err = pppol2tp_session_getsockopt(sk, session, optname, &val); + if (err) + goto end_put_sess; + } err = -EFAULT; if (put_user(len, (int __user *) optlen)) @@ -1558,7 +1580,7 @@ static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd) static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd) { - pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx); + pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true); pd->session_idx++; if (pd->session == NULL) { @@ -1626,8 +1648,9 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v) { struct l2tp_session *session = v; struct l2tp_tunnel *tunnel = session->tunnel; - struct pppol2tp_session *ps = l2tp_session_priv(session); - struct pppox_sock *po = pppox_sk(ps->sock); + unsigned char state; + char user_data_ok; + struct sock *sk; u32 ip = 0; u16 port = 0; @@ -1637,6 +1660,15 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v) port = ntohs(inet->inet_sport); } + sk = pppol2tp_session_get_sock(session); + if (sk) { + state = sk->sk_state; + user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N'; + } else { + state = 0; + user_data_ok = 'N'; + } + seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> " "%04X/%04X %d %c\n", session->name, ip, port, @@ -1644,9 +1676,7 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v) session->session_id, tunnel->peer_tunnel_id, session->peer_session_id, - ps->sock->sk_state, - (session == ps->sock->sk_user_data) ? - 'Y' : 'N'); + state, user_data_ok); seq_printf(m, " %d/%d/%c/%c/%s %08x %u\n", session->mtu, session->mru, session->recv_seq ? 'R' : '-', @@ -1663,8 +1693,12 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v) (unsigned long long)session->stats.rx_bytes, (unsigned long long)session->stats.rx_errors); - if (po) + if (sk) { + struct pppox_sock *po = pppox_sk(sk); + seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan)); + sock_put(sk); + } } static int pppol2tp_seq_show(struct seq_file *m, void *v) @@ -1685,10 +1719,14 @@ static int pppol2tp_seq_show(struct seq_file *m, void *v) /* Show the tunnel or session context. */ - if (pd->session == NULL) + if (!pd->session) { pppol2tp_seq_tunnel_show(m, pd->tunnel); - else + } else { pppol2tp_seq_session_show(m, pd->session); + if (pd->session->deref) + pd->session->deref(pd->session); + l2tp_session_dec_refcount(pd->session); + } out: return 0; @@ -1777,14 +1815,15 @@ static const struct proto_ops pppol2tp_ops = { static const struct pppox_proto pppol2tp_proto = { .create = pppol2tp_create, - .ioctl = pppol2tp_ioctl + .ioctl = pppol2tp_ioctl, + .owner = THIS_MODULE, }; #ifdef CONFIG_L2TP_V3 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = { .session_create = pppol2tp_session_create, - .session_delete = pppol2tp_session_delete, + .session_delete = l2tp_session_delete, }; #endif /* CONFIG_L2TP_V3 */