linux-toradex.git/net/l2tp, branch v4.9.78

l2tp: cleanup l2tp_tunnel_delete calls

2017-12-20T09:07:31+00:00

[ Upstream commit 4dc12ffeaeac939097a3f55c881d3dc3523dff0c ]

l2tp_tunnel_delete does not return anything since commit 62b982eeb458
("l2tp: fix race condition in l2tp_tunnel_delete").  But call sites of
l2tp_tunnel_delete still do casts to void to avoid unused return value
warnings.

Kill these now useless casts.

Signed-off-by: Jiri Slaby 
Cc: Sabrina Dubroca 
Cc: Guillaume Nault 
Cc: David S. Miller 
Cc: netdev@vger.kernel.org
Acked-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

l2tp: take remote address into account in l2tp_ip and l2tp_ip6 socket lookups

2017-12-09T21:01:50+00:00

[ Upstream commit a9b2dff80be979432484afaf7f8d8e73f9e8838a ]

For connected sockets, __l2tp_ip{,6}_bind_lookup() needs to check the
remote IP when looking for a matching socket. Otherwise a connected
socket can receive traffic not originating from its peer.

Drop l2tp_ip_bind_lookup() and l2tp_ip6_bind_lookup() instead of
updating their prototype, as these functions aren't used.

Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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

2017-11-18T10:22:21+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 race condition in l2tp_tunnel_delete

2017-10-12T09:51:22+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: Avoid schedule while atomic in exit_net

2017-10-12T09:51:22+00:00

[ Upstream commit 12d656af4e3d2781b9b9f52538593e1717e7c979 ]

While destroying a network namespace that contains a L2TP tunnel a
"BUG: scheduling while atomic" can be observed.

Enabling lockdep shows that this is happening because l2tp_exit_net()
is calling l2tp_tunnel_closeall() (via l2tp_tunnel_delete()) from
within an RCU critical section.

l2tp_exit_net() takes rcu_read_lock_bh()
  << list_for_each_entry_rcu() >>
  l2tp_tunnel_delete()
    l2tp_tunnel_closeall()
      __l2tp_session_unhash()
        synchronize_rcu() << Illegal inside RCU critical section >>

BUG: sleeping function called from invalid context
in_atomic(): 1, irqs_disabled(): 0, pid: 86, name: kworker/u16:2
INFO: lockdep is turned off.
CPU: 2 PID: 86 Comm: kworker/u16:2 Tainted: G        W  O    4.4.6-at1 #2
Hardware name: Xen HVM domU, BIOS 4.6.1-xs125300 05/09/2016
Workqueue: netns cleanup_net
 0000000000000000 ffff880202417b90 ffffffff812b0013 ffff880202410ac0
 ffffffff81870de8 ffff880202417bb8 ffffffff8107aee8 ffffffff81870de8
 0000000000000c51 0000000000000000 ffff880202417be0 ffffffff8107b024
Call Trace:
 [] dump_stack+0x85/0xc2
 [] ___might_sleep+0x148/0x240
 [] __might_sleep+0x44/0x80
 [] synchronize_sched+0x2d/0xe0
 [] ? trace_hardirqs_on+0xd/0x10
 [] ? __local_bh_enable_ip+0x6b/0xc0
 [] ? _raw_spin_unlock_bh+0x30/0x40
 [] __l2tp_session_unhash+0x172/0x220
 [] ? __l2tp_session_unhash+0x87/0x220
 [] l2tp_tunnel_closeall+0x9b/0x140
 [] l2tp_tunnel_delete+0x14/0x60
 [] l2tp_exit_net+0x110/0x270
 [] ? l2tp_exit_net+0x9c/0x270
 [] ops_exit_list.isra.6+0x33/0x60
 [] cleanup_net+0x1b6/0x280
 ...

This bug can easily be reproduced with a few steps:

 $ sudo unshare -n bash  # Create a shell in a new namespace
 # ip link set lo up
 # ip addr add 127.0.0.1 dev lo
 # ip l2tp add tunnel remote 127.0.0.1 local 127.0.0.1 tunnel_id 1 \
    peer_tunnel_id 1 udp_sport 50000 udp_dport 50000
 # ip l2tp add session name foo tunnel_id 1 session_id 1 \
    peer_session_id 1
 # ip link set foo up
 # exit  # Exit the shell, in turn exiting the namespace
 $ dmesg
 ...
 [942121.089216] BUG: scheduling while atomic: kworker/u16:3/13872/0x00000200
 ...

To fix this, move the call to l2tp_tunnel_closeall() out of the RCU
critical section, and instead call it from l2tp_tunnel_del_work(), which
is running from the l2tp_wq workqueue.

Fixes: 2b551c6e7d5b ("l2tp: close sessions before initiating tunnel delete")
Signed-off-by: Ridge Kennedy 
Acked-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

l2tp: consider '::' as wildcard address in l2tp_ip6 socket lookup

2017-08-07T01:59:46+00:00

[ Upstream commit 97b84fd6d91766ea57dcc350d78f42639e011c30 ]

An L2TP socket bound to the unspecified address should match with any
address. If not, it can't receive any packet and __l2tp_ip6_bind_lookup()
can't prevent another socket from binding on the same device/tunnel ID.

While there, rename the 'addr' variable to 'sk_laddr' (local addr), to
make following patch clearer.

Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

l2tp: take a reference on sessions used in genetlink handlers

2017-07-05T12:40:19+00:00

commit 2777e2ab5a9cf2b4524486c6db1517a6ded25261 upstream.

Callers of l2tp_nl_session_find() need to hold a reference on the
returned session since there's no guarantee that it isn't going to
disappear from under them.

Relying on the fact that no l2tp netlink message may be processed
concurrently isn't enough: sessions can be deleted by other means
(e.g. by closing the PPPOL2TP socket of a ppp pseudowire).

l2tp_nl_cmd_session_delete() is a bit special: it runs a callback
function that may require a previous call to session->ref(). In
particular, for ppp pseudowires, the callback is l2tp_session_delete(),
which then calls pppol2tp_session_close() and dereferences the PPPOL2TP
socket. The socket might already be gone at the moment
l2tp_session_delete() calls session->ref(), so we need to take a
reference during the session lookup. So we need to pass the do_ref
variable down to l2tp_session_get() and l2tp_session_get_by_ifname().

Since all callers have to be updated, l2tp_session_find_by_ifname() and
l2tp_nl_session_find() are renamed to reflect their new behaviour.

Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Amit Pundir 
Signed-off-by: Greg Kroah-Hartman

l2tp: hold session while sending creation notifications

2017-07-05T12:40:18+00:00

commit 5e6a9e5a3554a5b3db09cdc22253af1849c65dff upstream.

l2tp_session_find() doesn't take any reference on the returned session.
Therefore, the session may disappear while sending the notification.

Use l2tp_session_get() instead and decrement session's refcount once
the notification is sent.

Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners")
Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Amit Pundir 
Signed-off-by: Greg Kroah-Hartman

l2tp: fix duplicate session creation

2017-07-05T12:40:18+00:00

commit dbdbc73b44782e22b3b4b6e8b51e7a3d245f3086 upstream.

l2tp_session_create() relies on its caller for checking for duplicate
sessions. This is racy since a session can be concurrently inserted
after the caller's verification.

Fix this by letting l2tp_session_create() verify sessions uniqueness
upon insertion. Callers need to be adapted to check for
l2tp_session_create()'s return code instead of calling
l2tp_session_find().

pppol2tp_connect() is a bit special because it has to work on existing
sessions (if they're not connected) or to create a new session if none
is found. When acting on a preexisting session, a reference must be
held or it could go away on us. So we have to use l2tp_session_get()
instead of l2tp_session_find() and drop the reference before exiting.

Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support")
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: Amit Pundir 
Signed-off-by: Greg Kroah-Hartman

l2tp: ensure session can't get removed during pppol2tp_session_ioctl()

2017-07-05T12:40:18+00:00

commit 57377d63547861919ee634b845c7caa38de4a452 upstream.

Holding a reference on session is required before calling
pppol2tp_session_ioctl(). The session could get freed while processing the
ioctl otherwise. Since pppol2tp_session_ioctl() uses the session's socket,
we also need to take a reference on it in l2tp_session_get().

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: Amit Pundir 
Signed-off-by: Greg Kroah-Hartman