kernel/git/stable/linux.git/net/l2tp, branch linux-4.13.y

l2tp: don't use l2tp_tunnel_find() in l2tp_ip and l2tp_ip6

2017-11-24T07:35:56+00:00

[ Upstream commit 8f7dc9ae4a7aece9fbc3e6637bdfa38b36bcdf09 ] Using l2tp_tunnel_find() in l2tp_ip_recv() is wrong for two reasons: * It doesn't take a reference on the returned tunnel, which makes the call racy wrt. concurrent tunnel deletion. * The lookup is only based on the tunnel identifier, so it can return a tunnel that doesn't match the packet's addresses or protocol. For example, a packet sent to an L2TPv3 over IPv6 tunnel can be delivered to an L2TPv2 over UDPv4 tunnel. This is worse than a simple cross-talk: when delivering the packet to an L2TP over UDP tunnel, the corresponding socket is UDP, where ->sk_backlog_rcv() is NULL. Calling sk_receive_skb() will then crash the kernel by trying to execute this callback. And l2tp_tunnel_find() isn't even needed here. __l2tp_ip_bind_lookup() properly checks the socket binding and connection settings. It was used as a fallback mechanism for finding tunnels that didn't have their data path registered yet. But it's not limited to this case and can be used to replace l2tp_tunnel_find() in the general case. Fix l2tp_ip6 in the same way. Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support") Fixes: a32e0eec7042 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

l2tp: hold tunnel in pppol2tp_connect()

2017-11-18T10:30:39+00:00

[ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

l2tp: check ps->sock before running pppol2tp_session_ioctl()

2017-11-18T10:30:36+00:00

[ Upstream commit 5903f594935a3841137c86b9d5b75143a5b7121c ] When pppol2tp_session_ioctl() is called by pppol2tp_tunnel_ioctl(), the session may be unconnected. That is, it was created by pppol2tp_session_create() and hasn't been connected with pppol2tp_connect(). In this case, ps->sock is NULL, so we need to check for this case in order to avoid dereferencing a NULL pointer. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

l2tp: fix l2tp_eth module loading

2017-10-12T09:56:07+00:00

[ Upstream commit 9f775ead5e570e7e19015b9e4e2f3dd6e71a5935 ] The l2tp_eth module crashes if its netlink callbacks are run when the pernet data aren't initialised. We should normally register_pernet_device() before the genl callbacks. However, the pernet data only maintain a list of l2tpeth interfaces, and this list is never used. So let's just drop pernet handling instead. Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

l2tp: fix race condition in l2tp_tunnel_delete

2017-10-12T09:56:05+00:00

[ Upstream commit 62b982eeb4589b2e6d7c01a90590e3a4c2b2ca19 ] If we try to delete the same tunnel twice, the first delete operation does a lookup (l2tp_tunnel_get), finds the tunnel, calls l2tp_tunnel_delete, which queues it for deletion by l2tp_tunnel_del_work. The second delete operation also finds the tunnel and calls l2tp_tunnel_delete. If the workqueue has already fired and started running l2tp_tunnel_del_work, then l2tp_tunnel_delete will queue the same tunnel a second time, and try to free the socket again. Add a dead flag to prevent firing the workqueue twice. Then we can remove the check of queue_work's result that was meant to prevent that race but doesn't. Reproducer: ip l2tp add tunnel tunnel_id 3000 peer_tunnel_id 4000 local 192.168.0.2 remote 192.168.0.1 encap udp udp_sport 5000 udp_dport 6000 ip l2tp add session name l2tp1 tunnel_id 3000 session_id 1000 peer_session_id 2000 ip link set l2tp1 up ip l2tp del tunnel tunnel_id 3000 ip l2tp del tunnel tunnel_id 3000 Fixes: f8ccac0e4493 ("l2tp: put tunnel socket release on a workqueue") Reported-by: Jianlin Shi Signed-off-by: Sabrina Dubroca Acked-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

l2tp: hold tunnel used while creating sessions with netlink

2017-08-28T18:34:58+00:00

Use l2tp_tunnel_get() to retrieve tunnel, so that it can't go away on us. Otherwise l2tp_tunnel_destruct() might release the last reference count concurrently, thus freeing the tunnel while we're using it. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: hold tunnel while handling genl TUNNEL_GET commands

2017-08-28T18:34:58+00:00

Use l2tp_tunnel_get() instead of l2tp_tunnel_find() so that we get a reference on the tunnel, preventing l2tp_tunnel_destruct() from freeing it from under us. Also move l2tp_tunnel_get() below nlmsg_new() so that we only take the reference when needed. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: hold tunnel while handling genl tunnel updates

2017-08-28T18:34:58+00:00

We need to make sure the tunnel is not going to be destroyed by l2tp_tunnel_destruct() concurrently. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: hold tunnel while processing genl delete command

2017-08-28T18:34:58+00:00

l2tp_nl_cmd_tunnel_delete() needs to take a reference on the tunnel, to prevent it from being concurrently freed by l2tp_tunnel_destruct(). Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: hold tunnel while looking up sessions in l2tp_netlink

2017-08-28T18:34:58+00:00

l2tp_tunnel_find() doesn't take a reference on the returned tunnel. Therefore, it's unsafe to use it because the returned tunnel can go away on us anytime. Fix this by defining l2tp_tunnel_get(), which works like l2tp_tunnel_find(), but takes a reference on the returned tunnel. Caller then has to drop this reference using l2tp_tunnel_dec_refcount(). As l2tp_tunnel_dec_refcount() needs to be moved to l2tp_core.h, let's simplify the patch and not move the L2TP_REFCNT_DEBUG part. This code has been broken (not even compiling) in May 2012 by commit a4ca44fa578c ("net: l2tp: Standardize logging styles") and fixed more than two years later by commit 29abe2fda54f ("l2tp: fix missing line continuation"). So it doesn't appear to be used by anyone. Same thing for l2tp_tunnel_free(); instead of moving it to l2tp_core.h, let's just simplify things and call kfree_rcu() directly in l2tp_tunnel_dec_refcount(). Extra assertions and debugging code provided by l2tp_tunnel_free() didn't help catching any of the reference counting and socket handling issues found while working on this series. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller