Commit Graph

107 Commits

Author SHA1 Message Date
Guillaume Nault 23fe846f9a l2tp: adjust comments about L2TPv3 offsets
The "offset" option has been removed by
commit 900631ee6a ("l2tp: remove configurable payload offset").

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-08 14:22:42 -05:00
James Chapman 900631ee6a l2tp: remove configurable payload offset
If L2TP_ATTR_OFFSET is set to a non-zero value in L2TPv3 tunnels, it
results in L2TPv3 packets being transmitted which might not be
compliant with the L2TPv3 RFC. This patch has l2tp ignore the offset
setting and send all packets with no offset.

In more detail:

L2TPv2 supports a variable offset from the L2TPv2 header to the
payload. The offset value is indicated by an optional field in the
L2TP header.  Our L2TP implementation already detects the presence of
the optional offset and skips that many bytes when handling data
received packets. All transmitted packets are always transmitted with
no offset.

L2TPv3 has no optional offset field in the L2TPv3 packet
header. Instead, L2TPv3 defines optional fields in a "Layer-2 Specific
Sublayer". At the time when the original L2TP code was written, there
was talk at IETF of offset being implemented in a new Layer-2 Specific
Sublayer. A L2TP_ATTR_OFFSET netlink attribute was added so that this
offset could be configured and the intention was to allow it to be
also used to set the tx offset for L2TPv2. However, no L2TPv3 offset
was ever specified and the L2TP_ATTR_OFFSET parameter was forgotten
about.

Setting L2TP_ATTR_OFFSET results in L2TPv3 packets being transmitted
with the specified number of bytes padding between L2TPv3 header and
payload. This is not compliant with L2TPv3 RFC3931. This change
removes the configurable offset altogether while retaining
L2TP_ATTR_OFFSET for backwards compatibility. Any L2TP_ATTR_OFFSET
value is ignored.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05 11:03:19 -05:00
James Chapman 863def15b9 l2tp: revert "l2tp: add peer_offset parameter"
Revert commit f15bc54eee ("l2tp: add peer_offset parameter"). This
is removed because it is adding another configurable offset and
configurable offsets are being removed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05 11:03:04 -05:00
Lorenzo Bianconi f15bc54eee l2tp: add peer_offset parameter
Introduce peer_offset parameter in order to add the capability
to specify two different values for payload offset on tx/rx side.
If just offset is provided by userspace use it for rx side as well
in order to maintain compatibility with older l2tp versions

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-27 12:11:51 -05:00
Vasily Averin 1e7af3b2cd l2tp: exit_net cleanup check added
Be sure that l2tp_session_hlist array initialized in net_init hook
was return to initial state.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-14 15:45:53 +09:00
Guillaume Nault 765924e362 l2tp: don't close sessions in l2tp_tunnel_destruct()
Sessions are already removed by the proto ->destroy() handlers, and
since commit f3c66d4e14 ("l2tp: prevent creation of sessions on terminated tunnels"),
we're guaranteed that no new session can be created afterwards.

Furthermore, l2tp_tunnel_closeall() can sleep when there are sessions
left to close. So we really shouldn't call it in a ->sk_destruct()
handler, as it can be used from atomic context.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 19:05:17 +09:00
Guillaume Nault c7fa745d98 l2tp: remove l2tp_tunnel_count and l2tp_session_count
These variables have never been used.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01 10:57:24 +09:00
Guillaume Nault a4346210c4 l2tp: remove ->ref() and ->deref()
The ->ref() and ->deref() callbacks are unused since PPP stopped using
them in ee40fb2e1e ("l2tp: protect sock pointer of struct pppol2tp_session with RCU").

We can thus remove them from struct l2tp_session and drop the do_ref
parameter of l2tp_session_get*().

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01 10:57:24 +09:00
Guillaume Nault 3953ae7b21 l2tp: don't register sessions in l2tp_session_create()
Sessions created by l2tp_session_create() aren't fully initialised:
some pseudo-wire specific operations need to be done before making the
session usable. Therefore the PPP and Ethernet pseudo-wires continue
working on the returned l2tp session while it's already been exposed to
the rest of the system.
This can lead to various issues. In particular, the session may enter
the deletion process before having been fully initialised, which will
confuse the session removal code.

This patch moves session registration out of l2tp_session_create(), so
that callers can control when the session is exposed to the rest of the
system. This is done by the new l2tp_session_register() function.

Only pppol2tp_session_create() can be easily converted to avoid
modifying its session after registration (the debug message is dropped
in order to avoid the need for holding a reference on the session).

For pppol2tp_connect() and l2tp_eth_create()), more work is needed.
That'll be done in followup patches. For now, let's just register the
session right after its creation, like it was done before. The only
difference is that we can easily take a reference on the session before
registering it, so, at least, we're sure it's not going to be freed
while we're working on it.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29 11:16:21 +09:00
Jiri Slaby 4dc12ffeae l2tp: cleanup l2tp_tunnel_delete calls
l2tp_tunnel_delete does not return anything since commit 62b982eeb4
("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 <jslaby@suse.cz>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Cc: Guillaume Nault <g.nault@alphalink.fr>
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 13:48:32 +09:00
Sabrina Dubroca 62b982eeb4 l2tp: fix race condition in l2tp_tunnel_delete
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: f8ccac0e44 ("l2tp: put tunnel socket release on a workqueue")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-26 10:24:34 -07:00
Guillaume Nault b228a94066 l2tp: fix race between l2tp_session_delete() and l2tp_tunnel_closeall()
There are several ways to remove L2TP sessions:

  * deleting a session explicitly using the netlink interface (with
    L2TP_CMD_SESSION_DELETE),
  * deleting the session's parent tunnel (either by closing the
    tunnel's file descriptor or using the netlink interface),
  * closing the PPPOL2TP file descriptor of a PPP pseudo-wire.

In some cases, when these methods are used concurrently on the same
session, the session can be removed twice, leading to use-after-free
bugs.

This patch adds a 'dead' flag, used by l2tp_session_delete() and
l2tp_tunnel_closeall() to prevent them from stepping on each other's
toes.

The session deletion path used when closing a PPPOL2TP file descriptor
doesn't need to be adapted. It already has to ensure that a session
remains valid for the lifetime of its PPPOL2TP file descriptor.
So it takes an extra reference on the session in the ->session_close()
callback (pppol2tp_session_close()), which is eventually dropped
in the ->sk_destruct() callback of the PPPOL2TP socket
(pppol2tp_session_destruct()).
Still, __l2tp_session_unhash() and l2tp_session_queue_purge() can be
called twice and even concurrently for a given session, but thanks to
proper locking and re-initialisation of list fields, this is not an
issue.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-25 14:44:41 -07:00
Guillaume Nault f3c66d4e14 l2tp: prevent creation of sessions on terminated tunnels
l2tp_tunnel_destruct() sets tunnel->sock to NULL, then removes the
tunnel from the pernet list and finally closes all its sessions.
Therefore, it's possible to add a session to a tunnel that is still
reachable, but for which tunnel->sock has already been reset. This can
make l2tp_session_create() dereference a NULL pointer when calling
sock_hold(tunnel->sock).

This patch adds the .acpt_newsess field to struct l2tp_tunnel, which is
used by l2tp_tunnel_closeall() to prevent addition of new sessions to
tunnels. Resetting tunnel->sock is done after l2tp_tunnel_closeall()
returned, so that l2tp_session_add_to_tunnel() can safely take a
reference on it when .acpt_newsess is true.

The .acpt_newsess field is modified in l2tp_tunnel_closeall(), rather
than in l2tp_tunnel_destruct(), so that it benefits all tunnel removal
mechanisms. E.g. on UDP tunnels, a session could be added to a tunnel
after l2tp_udp_encap_destroy() proceeded. This would prevent the tunnel
from being removed because of the references held by this new session
on the tunnel and its socket. Even though the session could be removed
manually later on, this defeats the purpose of
commit 9980d001ce ("l2tp: add udp encap socket destroy handler").

Fixes: fd558d186d ("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>
2017-09-03 11:04:21 -07:00
Guillaume Nault 54652eb12c l2tp: hold tunnel while looking up sessions in l2tp_netlink
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 a4ca44fa57 ("net: l2tp: Standardize logging styles")
and fixed more than two years later by
commit 29abe2fda5 ("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: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28 11:34:58 -07:00
Guillaume Nault 9ee369a405 l2tp: initialise session's refcount before making it reachable
Sessions must be fully initialised before calling
l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame
where partially initialised sessions can be accessed by external users.

Fixes: dbdbc73b44 ("l2tp: fix duplicate session creation")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28 11:28:33 -07:00
Reshetova, Elena f00c854c96 net, l2tp: convert l2tp_session.ref_count from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-04 22:35:15 +01:00
Reshetova, Elena fbea9e0760 net, l2tp: convert l2tp_tunnel.ref_count from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-04 22:35:15 +01:00
Guillaume Nault 2f858b928b l2tp: define parameters of l2tp_tunnel_find*() as "const"
l2tp_tunnel_find() and l2tp_tunnel_find_nth() don't modify "net".

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-12 10:44:02 -04:00
Guillaume Nault 9aaef50c44 l2tp: define parameters of l2tp_session_get*() as "const"
Make l2tp_pernet()'s parameter constant, so that l2tp_session_get*() can
declare their "net" variable as "const".
Also constify "ifname" in l2tp_session_get_by_ifname().

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-12 10:44:02 -04:00
Guillaume Nault 55a3ce3b9d l2tp: remove l2tp_session_find()
This function isn't used anymore.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11 13:48:09 -04:00
Guillaume Nault e08293a4cc l2tp: take reference on sessions being dumped
Take a reference on the sessions returned by l2tp_session_find_nth()
(and rename it l2tp_session_get_nth() to reflect this change), so that
caller is assured that the session isn't going to disappear while
processing it.

For procfs and debugfs handlers, the session is held in the .start()
callback and dropped in .show(). Given that pppol2tp_seq_session_show()
dereferences the associated PPPoL2TP socket and that
l2tp_dfs_seq_session_show() might call pppol2tp_show(), we also need to
call the session's .ref() callback to prevent the socket from going
away from under us.

Fixes: fd558d186d ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Fixes: 0ad6614048 ("l2tp: Add debugfs files for dumping l2tp debug info")
Fixes: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-04 10:00:56 -07:00
Guillaume Nault 2777e2ab5a l2tp: take a reference on sessions used in genetlink handlers
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: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-01 20:16:41 -07:00
Guillaume Nault dbdbc73b44 l2tp: fix duplicate session creation
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: d9e31d17ce ("l2tp: Add L2TP ethernet pseudowire support")
Fixes: fd558d186d ("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>
2017-04-01 20:16:41 -07:00
Guillaume Nault 61b9a04772 l2tp: fix race in l2tp_recv_common()
Taking a reference on sessions in l2tp_recv_common() is racy; this
has to be done by the callers.

To this end, a new function is required (l2tp_session_get()) to
atomically lookup a session and take a reference on it. Callers then
have to manually drop this reference.

Fixes: fd558d186d ("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>
2017-04-01 20:16:41 -07:00
Alexey Dobriyan 5b5e0928f7 lib/vsprintf.c: remove %Z support
Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement.  Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:47 -08:00
Ridge Kennedy 12d656af4e l2tp: Avoid schedule while atomic in exit_net
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:
 [<ffffffff812b0013>] dump_stack+0x85/0xc2
 [<ffffffff8107aee8>] ___might_sleep+0x148/0x240
 [<ffffffff8107b024>] __might_sleep+0x44/0x80
 [<ffffffff810b21bd>] synchronize_sched+0x2d/0xe0
 [<ffffffff8109be6d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff8105c7bb>] ? __local_bh_enable_ip+0x6b/0xc0
 [<ffffffff816a1b00>] ? _raw_spin_unlock_bh+0x30/0x40
 [<ffffffff81667482>] __l2tp_session_unhash+0x172/0x220
 [<ffffffff81667397>] ? __l2tp_session_unhash+0x87/0x220
 [<ffffffff8166888b>] l2tp_tunnel_closeall+0x9b/0x140
 [<ffffffff81668c74>] l2tp_tunnel_delete+0x14/0x60
 [<ffffffff81668dd0>] l2tp_exit_net+0x110/0x270
 [<ffffffff81668d5c>] ? l2tp_exit_net+0x9c/0x270
 [<ffffffff815001c3>] ops_exit_list.isra.6+0x33/0x60
 [<ffffffff81501166>] 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: 2b551c6e7d ("l2tp: close sessions before initiating tunnel delete")
Signed-off-by: Ridge Kennedy <ridge.kennedy@alliedtelesis.co.nz>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-22 15:59:53 -05:00
Asbjørn Sloth Tønnesen 3f9b9770b4 net: l2tp: fix negative assignment to unsigned int
recv_seq, send_seq and lns_mode mode are all defined as
unsigned int foo:1;

Signed-off-by: Asbjoern Sloth Toennesen <asbjorn@asbjorn.st>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-09 18:55:36 -05:00
Sabrina Dubroca 2f86953e74 l2tp: fix use-after-free during module unload
Tunnel deletion is delayed by both a workqueue (l2tp_tunnel_delete -> wq
 -> l2tp_tunnel_del_work) and RCU (sk_destruct -> RCU ->
l2tp_tunnel_destruct).

By the time l2tp_tunnel_destruct() runs to destroy the tunnel and finish
destroying the socket, the private data reserved via the net_generic
mechanism has already been freed, but l2tp_tunnel_destruct() actually
uses this data.

Make sure tunnel deletion for the netns has completed before returning
from l2tp_exit_net() by first flushing the tunnel removal workqueue, and
then waiting for RCU callbacks to complete.

Fixes: 167eb17e0b ("l2tp: create tunnel sockets in the right namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 11:44:44 -07:00
Guillaume Nault a5c5e2da85 l2tp: fix configuration passed to setup_udp_tunnel_sock()
Unused fields of udp_cfg must be all zeros. Otherwise
setup_udp_tunnel_sock() fills ->gro_receive and ->gro_complete
callbacks with garbage, eventually resulting in panic when used by
udp_gro_receive().

[   72.694123] BUG: unable to handle kernel paging request at ffff880033f87d78
[   72.695518] IP: [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530] PGD 26e2067 PUD 26e3067 PMD 342ed063 PTE 8000000033f87163
[   72.696530] Oops: 0011 [#1] SMP KASAN
[   72.696530] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6_udp_tunnel udp_tunnel pptp gre pppox ppp_generic slhc crc32c_intel ghash_clmulni_intel jitterentropy_rng sha256_generic hmac drbg ansi_cprng aesni_intel evdev aes_x86_64 ablk_helper cryptd lrw gf128mul glue_helper serio_raw acpi_cpufreq button proc\
essor ext4 crc16 jbd2 mbcache virtio_blk virtio_net virtio_pci virtio_ring virtio
[   72.696530] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.7.0-rc1 #1
[   72.696530] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   72.696530] task: ffff880035b59700 ti: ffff880035b70000 task.ti: ffff880035b70000
[   72.696530] RIP: 0010:[<ffff880033f87d78>]  [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530] RSP: 0018:ffff880035f87bc0  EFLAGS: 00010246
[   72.696530] RAX: ffffed000698f996 RBX: ffff88003326b840 RCX: ffffffff814cc823
[   72.696530] RDX: ffff88003326b840 RSI: ffff880033e48038 RDI: ffff880034c7c780
[   72.696530] RBP: ffff880035f87c18 R08: 000000000000a506 R09: 0000000000000000
[   72.696530] R10: ffff880035f87b38 R11: ffff880034b9344d R12: 00000000ebfea715
[   72.696530] R13: 0000000000000000 R14: ffff880034c7c780 R15: 0000000000000000
[   72.696530] FS:  0000000000000000(0000) GS:ffff880035f80000(0000) knlGS:0000000000000000
[   72.696530] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   72.696530] CR2: ffff880033f87d78 CR3: 0000000033c98000 CR4: 00000000000406a0
[   72.696530] Stack:
[   72.696530]  ffffffff814cc834 ffff880034b93468 0000001481416818 ffff88003326b874
[   72.696530]  ffff880034c7ccb0 ffff880033e48038 ffff88003326b840 ffff880034b93462
[   72.696530]  ffff88003326b88a ffff88003326b88c ffff880034b93468 ffff880035f87c70
[   72.696530] Call Trace:
[   72.696530]  <IRQ>
[   72.696530]  [<ffffffff814cc834>] ? udp_gro_receive+0x1c6/0x1f9
[   72.696530]  [<ffffffff814ccb1c>] udp4_gro_receive+0x2b5/0x310
[   72.696530]  [<ffffffff814d989b>] inet_gro_receive+0x4a3/0x4cd
[   72.696530]  [<ffffffff81431b32>] dev_gro_receive+0x584/0x7a3
[   72.696530]  [<ffffffff810adf7a>] ? __lock_is_held+0x29/0x64
[   72.696530]  [<ffffffff814321f7>] napi_gro_receive+0x124/0x21d
[   72.696530]  [<ffffffffa000b145>] virtnet_receive+0x8df/0x8f6 [virtio_net]
[   72.696530]  [<ffffffffa000b27e>] virtnet_poll+0x1d/0x8d [virtio_net]
[   72.696530]  [<ffffffff81431350>] net_rx_action+0x15b/0x3b9
[   72.696530]  [<ffffffff815893d6>] __do_softirq+0x216/0x546
[   72.696530]  [<ffffffff81062392>] irq_exit+0x49/0xb6
[   72.696530]  [<ffffffff81588e9a>] do_IRQ+0xe2/0xfa
[   72.696530]  [<ffffffff81587a49>] common_interrupt+0x89/0x89
[   72.696530]  <EOI>
[   72.696530]  [<ffffffff810b05df>] ? trace_hardirqs_on_caller+0x229/0x270
[   72.696530]  [<ffffffff8102b3c7>] ? default_idle+0x1c/0x2d
[   72.696530]  [<ffffffff8102b3c5>] ? default_idle+0x1a/0x2d
[   72.696530]  [<ffffffff8102bb8c>] arch_cpu_idle+0xa/0xc
[   72.696530]  [<ffffffff810a6c39>] default_idle_call+0x1a/0x1c
[   72.696530]  [<ffffffff810a6d96>] cpu_startup_entry+0x15b/0x20f
[   72.696530]  [<ffffffff81039a81>] start_secondary+0x12c/0x133
[   72.696530] Code: ff ff ff ff ff ff ff ff ff ff 7f ff ff ff ff ff ff ff 7f 00 7e f8 33 00 88 ff ff 6d 61 58 81 ff ff ff ff 5e de 0a 81 ff ff ff ff <00> 5c e2 34 00 88 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00
[   72.696530] RIP  [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530]  RSP <ffff880035f87bc0>
[   72.696530] CR2: ffff880033f87d78
[   72.696530] ---[ end trace ad7758b9a1dccf99 ]---
[   72.696530] Kernel panic - not syncing: Fatal exception in interrupt
[   72.696530] Kernel Offset: disabled
[   72.696530] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

v2: use empty initialiser instead of "{ NULL }" to avoid relying on
    first field's type.

Fixes: 38fd2af24f ("udp: Add socket based GRO and config")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-08 11:11:53 -07:00
Wang Shanker 018f825858 net: l2tp: fix reversed udp6 checksum flags
This patch fixes a bug which causes the behavior of whether to ignore
udp6 checksum of udp6 encapsulated l2tp tunnel contrary to what
userspace program requests.

When the flag `L2TP_ATTR_UDP_ZERO_CSUM6_RX` is set by userspace, it is
expected that udp6 checksums of received packets of the l2tp tunnel
to create should be ignored. In `l2tp_netlink.c`:
`l2tp_nl_cmd_tunnel_create()`, `cfg.udp6_zero_rx_checksums` is set
according to the flag, and then passed to `l2tp_core.c`:
`l2tp_tunnel_create()` and then `l2tp_tunnel_sock_create()`. In
`l2tp_tunnel_sock_create()`, `udp_conf.use_udp6_rx_checksums` is set
the same to `cfg.udp6_zero_rx_checksums`. However, if we want the
checksum to be ignored, `udp_conf.use_udp6_rx_checksums` should be set
to `false`, i.e. be set to the contrary. Similarly, the same should be
done to `udp_conf.use_udp6_tx_checksums`.

Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-01 19:32:16 -04:00
Alexander Couzens 06a15f51cf l2tp: protect tunnel->del_work by ref_count
There is a small chance that tunnel_free() is called before tunnel->del_work scheduled
resulting in a zero pointer dereference.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-28 22:39:10 -07:00
Eric W. Biederman 26abe14379 net: Modify sk_alloc to not reference count the netns of kernel sockets.
Now that sk_alloc knows when a kernel socket is being allocated modify
it to not reference count the network namespace of kernel sockets.

Keep track of if a socket needs reference counting by adding a flag to
struct sock called sk_net_refcnt.

Update all of the callers of sock_create_kern to stop using
sk_change_net and sk_release_kernel as those hacks are no longer
needed, to avoid reference counting a kernel socket.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-11 10:50:18 -04:00
Eric W. Biederman eeb1bd5c40 net: Add a struct net parameter to sock_create_kern
This is long overdue, and is part of cleaning up how we allocate kernel
sockets that don't reference count struct net.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-11 10:50:17 -04:00
WANG Cong 67e04c29ec l2tp: unregister l2tp_net_ops on failure path
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-06 16:53:02 -04:00
Andy Zhou c8fffcea0a l2tp: Refactor l2tp core driver to make use of the common UDP tunnel functions
Simplify l2tp implementation using common UDP tunnel APIs.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-19 15:57:15 -04:00
Andy Zhou 29abe2fda5 l2tp: fix missing line continuation
This syntax error was covered by L2TP_REFCNT_DEBUG not being set by
default.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-05 15:19:53 -07:00
Tom Herbert 72297c59f7 l2tp: Enable checksum unnecessary conversions for l2tp/UDP sockets
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-01 21:36:28 -07:00
Tom Herbert 85644b4d0c l2tp: Call udp_sock_create
In l2tp driver call common function udp_sock_create to create the
listener UDP port.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-14 16:12:15 -07:00
Tom Herbert 77157e1973 l2tp: call udp{6}_set_csum
Call common functions to set checksum for UDP tunnel.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-04 22:46:38 -07:00
Tom Herbert 6b649feafe l2tp: Add support for zero IPv6 checksums
Added new L2TP configuration options to allow TX and RX of
zero checksums in IPv6. Default is not to use them.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23 16:28:53 -04:00
Tom Herbert 28448b8045 net: Split sk_no_check into sk_no_check_{rx,tx}
Define separate fields in the sock structure for configuring disabling
checksums in both TX and RX-- sk_no_check_tx and sk_no_check_rx.
The SO_NO_CHECK socket option only affects sk_no_check_tx. Also,
removed UDP_CSUM_* defines since they are no longer necessary.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23 16:28:53 -04:00
WANG Cong 60ff746739 net: rename local_df to ignore_df
As suggested by several people, rename local_df to ignore_df,
since it means "ignore df bit if it is set".

Cc: Maciej Żenczykowski <maze@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12 14:03:41 -04:00
Tom Herbert 58d6085c14 l2tp: Remove UDP checksum verification
Validating the UDP checksum is now done in UDP before handing
packets to the encapsulation layer. Note that this also eliminates
the "feature" where L2TP can ignore a non-zero UDP checksum (doing
this was contrary to RFC 1122).

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-08 23:47:50 -04:00
Eric Dumazet b0270e9101 ipv4: add a sock pointer to ip_queue_xmit()
ip_queue_xmit() assumes the skb it has to transmit is attached to an
inet socket. Commit 31c70d5956 ("l2tp: keep original skb ownership")
changed l2tp to not change skb ownership and thus broke this assumption.

One fix is to add a new 'struct sock *sk' parameter to ip_queue_xmit(),
so that we do not assume skb->sk points to the socket used by l2tp
tunnel.

Fixes: 31c70d5956 ("l2tp: keep original skb ownership")
Reported-by: Zhan Jianyu <nasa4836@gmail.com>
Tested-by: Zhan Jianyu <nasa4836@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-15 12:58:34 -04:00
Linus Torvalds cd6362befe Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:
 "Here is my initial pull request for the networking subsystem during
  this merge window:

   1) Support for ESN in AH (RFC 4302) from Fan Du.

   2) Add full kernel doc for ethtool command structures, from Ben
      Hutchings.

   3) Add BCM7xxx PHY driver, from Florian Fainelli.

   4) Export computed TCP rate information in netlink socket dumps, from
      Eric Dumazet.

   5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
      Dichtel.

   6) Convert many drivers to pci_enable_msix_range(), from Alexander
      Gordeev.

   7) Record SKB timestamps more efficiently, from Eric Dumazet.

   8) Switch to microsecond resolution for TCP round trip times, also
      from Eric Dumazet.

   9) Clean up and fix 6lowpan fragmentation handling by making use of
      the existing inet_frag api for it's implementation.

  10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.

  11) Auto size SKB lengths when composing netlink messages based upon
      past message sizes used, from Eric Dumazet.

  12) qdisc dumps can take a long time, add a cond_resched(), From Eric
      Dumazet.

  13) Sanitize netpoll core and drivers wrt.  SKB handling semantics.
      Get rid of never-used-in-tree netpoll RX handling.  From Eric W
      Biederman.

  14) Support inter-address-family and namespace changing in VTI tunnel
      driver(s).  From Steffen Klassert.

  15) Add Altera TSE driver, from Vince Bridgers.

  16) Optimizing csum_replace2() so that it doesn't adjust the checksum
      by checksumming the entire header, from Eric Dumazet.

  17) Expand BPF internal implementation for faster interpreting, more
      direct translations into JIT'd code, and much cleaner uses of BPF
      filtering in non-socket ocntexts.  From Daniel Borkmann and Alexei
      Starovoitov"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
  netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
  net: Add a test to see if a skb is freeable in irq context
  qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
  net: ptp: move PTP classifier in its own file
  net: sxgbe: make "core_ops" static
  net: sxgbe: fix logical vs bitwise operation
  net: sxgbe: sxgbe_mdio_register() frees the bus
  Call efx_set_channels() before efx->type->dimension_resources()
  xen-netback: disable rogue vif in kthread context
  net/mlx4: Set proper build dependancy with vxlan
  be2net: fix build dependency on VxLAN
  mac802154: make csma/cca parameters per-wpan
  mac802154: allow only one WPAN to be up at any given time
  net: filter: minor: fix kdoc in __sk_run_filter
  netlink: don't compare the nul-termination in nla_strcmp
  can: c_can: Avoid led toggling for every packet.
  can: c_can: Simplify TX interrupt cleanup
  can: c_can: Store dlc private
  can: c_can: Reduce register access
  can: c_can: Make the code readable
  ...
2014-04-02 20:53:45 -07:00
Linus Torvalds 9d919e8d5b Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue changes from Tejun Heo:
 "PREPARE_[DELAYED_]WORK() were used to change the work function of work
  items without fully reinitializing it; however, this makes workqueue
  consider the work item as a different one from before and allows the
  work item to start executing before the previous instance is finished
  which can lead to extremely subtle issues which are painful to debug.

  The interface has never been popular.  This pull request contains
  patches to remove existing usages and kill the interface.  As one of
  the changes was routed during the last devel cycle and another
  depended on a pending change in nvme, for-3.15 contains a couple merge
  commits.

  In addition, interfaces which were deprecated quite a while ago -
  __cancel_delayed_work() and WQ_NON_REENTRANT - are removed too"

* 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: remove deprecated WQ_NON_REENTRANT
  workqueue: Spelling s/instensive/intensive/
  workqueue: remove PREPARE_[DELAYED_]WORK()
  staging/fwserial: don't use PREPARE_WORK
  afs: don't use PREPARE_WORK
  nvme: don't use PREPARE_WORK
  usb: don't use PREPARE_DELAYED_WORK
  floppy: don't use PREPARE_[DELAYED_]WORK
  ps3-vuart: don't use PREPARE_WORK
  wireless/rt2x00: don't use PREPARE_WORK in rt2800usb.c
  workqueue: Remove deprecated __cancel_delayed_work()
2014-03-31 15:08:51 -07:00
ZhangZhen 59ff3eb6d6 workqueue: remove deprecated WQ_NON_REENTRANT
Tejun Heo has made WQ_NON_REENTRANT useless in the dbf2576e37
("workqueue: make all workqueues non-reentrant"). So remove its
usages and definition.

This patch doesn't introduce any behavior changes.

tj: minor description updates.

Signed-off-by: ZhangZhen <zhenzhang.zhang@huawei.com>
Sigend-off-by: Tejun Heo <tj@kernel.org>
Acked-by: James Chapman <jchapman@katalix.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
2014-03-29 09:33:03 -04:00
David S. Miller 85dcce7a73 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/usb/r8152.c
	drivers/net/xen-netback/netback.c

Both the r8152 and netback conflicts were simple overlapping
changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-14 22:31:55 -04:00
Eric Dumazet 746e349980 l2tp: fix unused variable warning
net/l2tp/l2tp_core.c:1111:15: warning: unused variable
'sk' [-Wunused-variable]

Fixes: 31c70d5956 ("l2tp: keep original skb ownership")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-10 15:32:24 -04:00
Eric Dumazet 31c70d5956 l2tp: keep original skb ownership
There is no reason to orphan skb in l2tp.

This breaks things like per socket memory limits, TCP Small queues...

Fix this before more people copy/paste it.

This is very similar to commit 8f646c922d
("vxlan: keep original skb ownership")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07 14:37:55 -05:00