14 Apr, 2018
2 commits
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Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe
against concurrent tunnel deletion.Use the same mechanism as in l2tp_ppp.c for dropping the reference
taken by l2tp_tunnel_get_nth(). That is, drop the reference just
before looking up the next tunnel. In case of error, drop the last
accessed tunnel in l2tp_dfs_seq_stop().That was the last use of l2tp_tunnel_find_nth().
Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller -
l2tp_tunnel_find_nth() is unsafe: no reference is held on the returned
tunnel, therefore it can be freed whenever the caller uses it.
This patch defines l2tp_tunnel_get_nth() which works similarly, but
also takes a reference on the returned tunnel. The caller then has to
drop it after it stops using the tunnel.Convert netlink dumps to make them safe against concurrent tunnel
deletion.Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
12 Apr, 2018
2 commits
-
We can't use l2tp_tunnel_find() to prevent l2tp_nl_cmd_tunnel_create()
from creating a duplicate tunnel. A tunnel can be concurrently
registered after l2tp_tunnel_find() returns. Therefore, searching for
duplicates must be done at registration time.Finally, remove l2tp_tunnel_find() entirely as it isn't use anywhere
anymore.Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller -
l2tp_tunnel_create() inserts the new tunnel into the namespace's tunnel
list and sets the socket's ->sk_user_data field, before returning it to
the caller. Therefore, there are two ways the tunnel can be accessed
and freed, before the caller even had the opportunity to take a
reference. In practice, syzbot could crash the module by closing the
socket right after a new tunnel was returned to pppol2tp_create().This patch moves tunnel registration out of l2tp_tunnel_create(), so
that the caller can safely hold a reference before publishing the
tunnel. This second step is done with the new l2tp_tunnel_register()
function, which is now responsible for associating the tunnel to its
socket and for inserting it into the namespace's list.While moving the code to l2tp_tunnel_register(), a few modifications
have been done. First, the socket validation tests are done in a helper
function, for clarity. Also, modifying the socket is now done after
having inserted the tunnel to the namespace's tunnels list. This will
allow insertion to fail, without having to revert theses modifications
in the error path (a followup patch will check for duplicate tunnels
before insertion). Either the socket is a kernel socket which we
control, or it is a user-space socket for which we have a reference on
the file descriptor. In any case, the socket isn't going to be closed
from under us.Reported-by: syzbot+fbeeb5c3b538e8545644@syzkaller.appspotmail.com
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
13 Mar, 2018
1 commit
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The l2tp_tunnel_create() function checks for v4mapped ipv6
sockets and cache that flag, so that l2tp core code can
reusing it at xmit time.If the socket is provided by the userspace, the connection
status of the tunnel sockets can change between the tunnel
creation and the xmit call, so that syzbot is able to
trigger the following splat:BUG: KASAN: use-after-free in ip6_dst_idev include/net/ip6_fib.h:192
[inline]
BUG: KASAN: use-after-free in ip6_xmit+0x1f76/0x2260
net/ipv6/ip6_output.c:264
Read of size 8 at addr ffff8801bd949318 by task syz-executor4/23448CPU: 0 PID: 23448 Comm: syz-executor4 Not tainted 4.16.0-rc4+ #65
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x24d lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report+0x23c/0x360 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
ip6_dst_idev include/net/ip6_fib.h:192 [inline]
ip6_xmit+0x1f76/0x2260 net/ipv6/ip6_output.c:264
inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
l2tp_xmit_core net/l2tp/l2tp_core.c:1053 [inline]
l2tp_xmit_skb+0x105f/0x1410 net/l2tp/l2tp_core.c:1148
pppol2tp_sendmsg+0x470/0x670 net/l2tp/l2tp_ppp.c:341
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:640
___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
__sys_sendmsg+0xe5/0x210 net/socket.c:2080
SYSC_sendmsg net/socket.c:2091 [inline]
SyS_sendmsg+0x2d/0x50 net/socket.c:2087
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x453e69
RSP: 002b:00007f819593cc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f819593d6d4 RCX: 0000000000453e69
RDX: 0000000000000081 RSI: 000000002037ffc8 RDI: 0000000000000004
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004c3 R14: 00000000006f72e8 R15: 0000000000000000This change addresses the issues:
* explicitly checking for TCP_ESTABLISHED for user space provided sockets
* dropping the v4mapped flag usage - it can become outdated - and
explicitly invoking ipv6_addr_v4mapped() insteadThe issue is apparently there since ancient times.
v1 -> v2: (many thanks to Guillaume)
- with csum issue introduced in v1
- replace pr_err with pr_debug
- fix build issue with IPV6 disabled
- move l2tp_sk_is_v4mapped in l2tp_core.cv2 -> v3:
- don't update inet_daddr for v4mapped address, unneeded
- drop rendundant check at creation timeReported-and-tested-by: syzbot+92fa328176eb07e4ac1a@syzkaller.appspotmail.com
Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core")
Signed-off-by: Paolo Abeni
Signed-off-by: David S. Miller
27 Feb, 2018
1 commit
-
The tunnel socket tunnel->sock (struct sock) is accessed when
preparing a new ppp session on a tunnel at pppol2tp_session_init. If
the socket is closed by a thread while another is creating a new
session, the threads race. In pppol2tp_connect, the tunnel object may
be created if the pppol2tp socket is associated with the special
session_id 0 and the tunnel socket is looked up using the provided
fd. When handling this, pppol2tp_connect cannot sock_hold the tunnel
socket to prevent it being destroyed during pppol2tp_connect since
this may itself may race with the socket being destroyed. Doing
sockfd_lookup in pppol2tp_connect isn't sufficient to prevent
tunnel->sock going away either because a given tunnel socket fd may be
reused between calls to pppol2tp_connect. Instead, have
l2tp_tunnel_create sock_hold the tunnel socket before it does
sockfd_put. This ensures that the tunnel's socket is always extant
while the tunnel object exists. Hold a ref on the socket until the
tunnel is destroyed and ensure that all tunnel destroy paths go
through a common function (l2tp_tunnel_delete) since this will do the
final sock_put to release the tunnel socket.Since the tunnel's socket is now guaranteed to exist if the tunnel
exists, we no longer need to use sockfd_lookup via l2tp_sock_to_tunnel
to derive the tunnel from the socket since this is always
sk_user_data.Also, sessions no longer sock_hold the tunnel socket since sessions
already hold a tunnel ref and the tunnel sock will not be freed until
the tunnel is freed. Removing these sock_holds in
l2tp_session_register avoids a possible sock leak in the
pppol2tp_connect error path if l2tp_session_register succeeds but
attaching a ppp channel fails. The pppol2tp_connect error path could
have been fixed instead and have the sock ref dropped when the session
is freed, but doing a sock_put of the tunnel socket when the session
is freed would require a new session_free callback. It is simpler to
just remove the sock_hold of the tunnel socket in
l2tp_session_register, now that the tunnel socket lifetime is
guaranteed.Finally, some init code in l2tp_tunnel_create is reordered to ensure
that the new tunnel object's refcount is set and the tunnel socket ref
is taken before the tunnel socket destructor callbacks are set.kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 4360 Comm: syzbot_19c09769 Not tainted 4.16.0-rc2+ #34
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
RIP: 0010:pppol2tp_session_init+0x1d6/0x500
RSP: 0018:ffff88001377fb40 EFLAGS: 00010212
RAX: dffffc0000000000 RBX: ffff88001636a940 RCX: ffffffff84836c1d
RDX: 0000000000000045 RSI: 0000000055976744 RDI: 0000000000000228
RBP: ffff88001377fb60 R08: ffffffff84836bc8 R09: 0000000000000002
R10: ffff88001377fab8 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88001636aac8 R14: ffff8800160f81c0 R15: 1ffff100026eff76
FS: 00007ffb3ea66700(0000) GS:ffff88001a400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020e77000 CR3: 0000000016261000 CR4: 00000000000006f0
Call Trace:
pppol2tp_connect+0xd18/0x13c0
? pppol2tp_session_create+0x170/0x170
? __might_fault+0x115/0x1d0
? lock_downgrade+0x860/0x860
? __might_fault+0xe5/0x1d0
? security_socket_connect+0x8e/0xc0
SYSC_connect+0x1b6/0x310
? SYSC_bind+0x280/0x280
? __do_page_fault+0x5d1/0xca0
? up_read+0x1f/0x40
? __do_page_fault+0x3c8/0xca0
SyS_connect+0x29/0x30
? SyS_accept+0x40/0x40
do_syscall_64+0x1e0/0x730
? trace_hardirqs_off_thunk+0x1a/0x1c
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7ffb3e376259
RSP: 002b:00007ffeda4f6508 EFLAGS: 00000202 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000020e77012 RCX: 00007ffb3e376259
RDX: 000000000000002e RSI: 0000000020e77000 RDI: 0000000000000004
RBP: 00007ffeda4f6540 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400b60
R13: 00007ffeda4f6660 R14: 0000000000000000 R15: 0000000000000000
Code: 80 3d b0 ff 06 02 00 0f 84 07 02 00 00 e8 13 d6 db fc 49 8d bc 24 28 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f
a 48 c1 ea 03 3c 02 00 0f 85 ed 02 00 00 4d 8b a4 24 28 02 00 00 e8 13 16Fixes: 80d84ef3ff1dd ("l2tp: prevent l2tp_tunnel_delete racing with userspace close")
Signed-off-by: James Chapman
Signed-off-by: David S. Miller
20 Jan, 2018
2 commits
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Remove l2specific_len configuration parameter since now L2-Specific
Sublayer length is computed according to l2specific_type provided by
userspace.Reviewed-by: Guillaume Nault
Tested-by: Guillaume Nault
Signed-off-by: Lorenzo Bianconi
Signed-off-by: David S. Miller -
Remove l2specific_len dependency while building l2tpv3 header or
parsing the received frame since default L2-Specific Sublayer is
always four bytes long and we don't need to rely on a user supplied
value.
Moreover in l2tp netlink code there are no sanity checks to
enforce the relation between l2specific_len and l2specific_type,
so sending a malformed netlink message is possible to set
l2specific_type to L2TP_L2SPECTYPE_DEFAULT (or even
L2TP_L2SPECTYPE_NONE) and set l2specific_len to a value greater than
4 leaking memory on the wire and sending corrupted frames.Reviewed-by: Guillaume Nault
Tested-by: Guillaume Nault
Signed-off-by: Lorenzo Bianconi
Signed-off-by: David S. Miller
06 Jan, 2018
2 commits
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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
Signed-off-by: David S. Miller -
Revert commit f15bc54eeecd ("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
Signed-off-by: David S. Miller
28 Dec, 2017
1 commit
-
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 versionsSigned-off-by: Lorenzo Bianconi
Signed-off-by: David S. Miller
01 Nov, 2017
2 commits
-
With conversion to refcount_t, such manual debugging code doesn't make
sense anymore.
The tunnel part was already dropped by
54652eb12c1b ("l2tp: hold tunnel while looking up sessions in l2tp_netlink").Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller -
The ->ref() and ->deref() callbacks are unused since PPP stopped using
them in ee40fb2e1eb5 ("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
Signed-off-by: David S. Miller
29 Oct, 2017
1 commit
-
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
Signed-off-by: David S. Miller
27 Sep, 2017
1 commit
-
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 3000Fixes: 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
26 Sep, 2017
1 commit
-
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
Signed-off-by: David S. Miller
04 Sep, 2017
2 commits
-
Using l2tp_tunnel_find() in pppol2tp_session_create() and
l2tp_eth_create() is racy, because no reference is held on the
returned session. These functions are only used to implement the
->session_create callback which is run by l2tp_nl_cmd_session_create().
Therefore searching for the parent tunnel isn't necessary because
l2tp_nl_cmd_session_create() already has a pointer to it and holds a
reference.This patch modifies ->session_create()'s prototype to directly pass the
the parent tunnel as parameter, thus avoiding searching for it in
pppol2tp_session_create() and l2tp_eth_create().Since we have to touch the ->session_create() call in
l2tp_nl_cmd_session_create(), let's also remove the useless conditional:
we know that ->session_create isn't NULL at this point because it's
already been checked earlier in this same function.Finally, one might be tempted to think that the removed
l2tp_tunnel_find() calls were harmless because they would return the
same tunnel as the one held by l2tp_nl_cmd_session_create() anyway.
But that tunnel might be removed and a new one created with same tunnel
Id before the l2tp_tunnel_find() call. In this case l2tp_tunnel_find()
would return the new tunnel which wouldn't be protected by the
reference held by l2tp_nl_cmd_session_create().Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller -
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 9980d001cec8 ("l2tp: add udp encap socket destroy handler").Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
29 Aug, 2017
1 commit
-
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
05 Jul, 2017
2 commits
-
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
Signed-off-by: Hans Liljestrand
Signed-off-by: Kees Cook
Signed-off-by: David Windsor
Signed-off-by: David S. Miller -
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
Signed-off-by: Hans Liljestrand
Signed-off-by: Kees Cook
Signed-off-by: David Windsor
Signed-off-by: David S. Miller
12 Apr, 2017
3 commits
-
l2tp_tunnel_find() and l2tp_tunnel_find_nth() don't modify "net".
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller -
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
Signed-off-by: David S. Miller -
This function isn't used anymore.
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
05 Apr, 2017
1 commit
-
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: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info")
Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
02 Apr, 2017
2 commits
-
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 -
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: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
11 Feb, 2017
1 commit
-
udp_ioctl(), as its name suggests, is used by UDP protocols,
but is also used by L2TP :(L2TP should use its own handler, because it really does not
look the same.SIOCINQ for instance should not assume UDP checksum or headers.
Thanks to Andrey and syzkaller team for providing the report
and a nice reproducer.While crashes only happen on recent kernels (after commit
7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue")), this
probably needs to be backported to older kernels.Fixes: 7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue")
Fixes: 85584672012e ("udp: Fix udp_poll() and ioctl()")
Signed-off-by: Eric Dumazet
Reported-by: Andrey Konovalov
Acked-by: Paolo Abeni
Signed-off-by: David S. Miller
11 Dec, 2016
1 commit
-
Move the L2TP_MSG_* definitions to UAPI, as it is part of
the netlink API.Signed-off-by: Asbjoern Sloth Toennesen
Signed-off-by: David S. Miller
11 Sep, 2016
1 commit
-
The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.Using the macro makes the code more readable by helping abstract away some
of the Kconfig built-in and module enable details.Signed-off-by: Javier Martinez Canillas
Signed-off-by: David S. Miller
26 Sep, 2015
1 commit
-
It should not be necessary to do explicit module loading when
configuring L2TP. Modules should be loaded as needed instead
(as is done already with netlink and other tunnel types).This patch adds a new module alias type and code to load
the sub module on demand.Signed-off-by: Stephen Hemminger
Signed-off-by: David S. Miller
24 May, 2014
1 commit
-
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
Signed-off-by: David S. Miller
07 Mar, 2014
1 commit
-
Commit e0d4435f "l2tp: Update PPP-over-L2TP driver to work over L2TPv3"
broke the PPPOL2TP_SO_SENDSEQ setsockopt. The L2TP header length was
previously computed by pppol2tp_l2t_header_len() before each call to
l2tp_xmit_skb(). Now that header length is retrieved from the hdr_len
session field, this field must be updated every time the L2TP header
format is modified, or l2tp_xmit_skb() won't push the right amount of
data for the L2TP header.This patch uses l2tp_session_set_header_len() to adjust hdr_len every
time sequencing is (de)activated from userspace (either by the
PPPOL2TP_SO_SENDSEQ setsockopt or the L2TP_ATTR_SEND_SEQ netlink
attribute).Signed-off-by: Guillaume Nault
Signed-off-by: David S. Miller
14 Jan, 2014
1 commit
-
Avoid needless export of local functions
Signed-off-by: Stephen Hemminger
Acked-by: James Chapman
Signed-off-by: David S. Miller
20 Oct, 2013
1 commit
-
There are a mix of function prototypes with and without extern
in the kernel sources. Standardize on not using extern for
function prototypes.Function prototypes don't need to be written with extern.
extern is assumed by the compiler. Its use is as unnecessary as
using auto to declare automatic/local variables in a block.Signed-off-by: Joe Perches
Signed-off-by: David S. Miller
03 Oct, 2013
1 commit
-
IPv4 mapped addresses cause kernel panic.
The patch juste check whether the IPv6 address is an IPv4 mapped
address. If so, use IPv4 API instead of IPv6.[ 940.026915] general protection fault: 0000 [#1]
[ 940.026915] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core pppox ppp_generic slhc loop psmouse
[ 940.026915] CPU: 0 PID: 3184 Comm: memcheck-amd64- Not tainted 3.11.0+ #1
[ 940.026915] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[ 940.026915] task: ffff880007130e20 ti: ffff88000737e000 task.ti: ffff88000737e000
[ 940.026915] RIP: 0010:[] [] ip6_xmit+0x276/0x326
[ 940.026915] RSP: 0018:ffff88000737fd28 EFLAGS: 00010286
[ 940.026915] RAX: c748521a75ceff48 RBX: ffff880000c30800 RCX: 0000000000000000
[ 940.026915] RDX: ffff88000075cc4e RSI: 0000000000000028 RDI: ffff8800060e5a40
[ 940.026915] RBP: ffff8800060e5a40 R08: 0000000000000000 R09: ffff88000075cc90
[ 940.026915] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000737fda0
[ 940.026915] R13: 0000000000000000 R14: 0000000000002000 R15: ffff880005d3b580
[ 940.026915] FS: 00007f163dc5e800(0000) GS:ffffffff81623000(0000) knlGS:0000000000000000
[ 940.026915] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 940.026915] CR2: 00000004032dc940 CR3: 0000000005c25000 CR4: 00000000000006f0
[ 940.026915] Stack:
[ 940.026915] ffff88000075cc4e ffffffff81694e90 ffff880000c30b38 0000000000000020
[ 940.026915] 11000000523c4bac ffff88000737fdb4 0000000000000000 ffff880000c30800
[ 940.026915] ffff880005d3b580 ffff880000c30b38 ffff8800060e5a40 0000000000000020
[ 940.026915] Call Trace:
[ 940.026915] [] ? inet6_csk_xmit+0xa4/0xc4
[ 940.026915] [] ? l2tp_xmit_skb+0x503/0x55a [l2tp_core]
[ 940.026915] [] ? pskb_expand_head+0x161/0x214
[ 940.026915] [] ? pppol2tp_xmit+0xf2/0x143 [l2tp_ppp]
[ 940.026915] [] ? ppp_channel_push+0x36/0x8b [ppp_generic]
[ 940.026915] [] ? ppp_write+0xaf/0xc5 [ppp_generic]
[ 940.026915] [] ? vfs_write+0xa2/0x106
[ 940.026915] [] ? SyS_write+0x56/0x8a
[ 940.026915] [] ? system_call_fastpath+0x16/0x1b
[ 940.026915] Code: 00 49 8b 8f d8 00 00 00 66 83 7c 11 02 00 74 60 49
8b 47 58 48 83 e0 fe 48 8b 80 18 01 00 00 48 85 c0 74 13 48 8b 80 78 02
00 00 ff 40 28 41 8b 57 68 48 01 50 30 48 8b 54 24 08 49 c7 c1 51
[ 940.026915] RIP [] ip6_xmit+0x276/0x326
[ 940.026915] RSP
[ 940.057945] ---[ end trace be8aba9a61c8b7f3 ]---
[ 940.058583] Kernel panic - not syncing: Fatal exception in interruptSigned-off-by: François CACHEREUL
Signed-off-by: David S. Miller
03 Jul, 2013
2 commits
-
If L2TP data sequence numbers are enabled and reordering is not
enabled, data reception stops if a packet is lost since the kernel
waits for a sequence number that is never resent. (When reordering is
enabled, data reception restarts when the reorder timeout expires.) If
no reorder timeout is set, we should count the number of in-sequence
packets after the out-of-sequence (OOS) condition is detected, and reset
sequence number state after a number of such packets are received.For now, the number of in-sequence packets while in OOS state which
cause the sequence number state to be reset is hard-coded to 5. This
could be configurable later.Signed-off-by: James Chapman
Signed-off-by: David S. Miller -
The L2TP datapath is not currently RFC-compliant when sequence numbers
are used in L2TP data packets. According to the L2TP RFC, any received
sequence number NR greater than or equal to the next expected NR is
acceptable, where the "greater than or equal to" test is determined by
the NR wrap point. This differs for L2TPv2 and L2TPv3, so add state in
the session context to hold the max NR value and the NR window size in
order to do the acceptable sequence number value check. These might be
configurable later, but for now we derive it from the tunnel L2TP
version, which determines the sequence number field size.Signed-off-by: James Chapman
Signed-off-by: David S. Miller
21 Mar, 2013
2 commits
-
If we postpone unhashing of l2tp sessions until the structure is freed, we
risk:1. further packets arriving and getting queued while the pseudowire is being
closed down
2. the recv path hitting "scheduling while atomic" errors in the case that
recv drops the last reference to a session and calls l2tp_session_free
while in atomic contextAs such, l2tp sessions should be unhashed from l2tp_core data structures early
in the teardown process prior to calling pseudowire close. For pseudowires
like l2tp_ppp which have multiple shutdown codepaths, provide an unhash hook.Signed-off-by: Tom Parkin
Signed-off-by: James Chapman
Signed-off-by: David S. Miller -
l2tp's u64_stats writers were incorrectly synchronised, making it possible to
deadlock a 64bit machine running a 32bit kernel simply by sending the l2tp
code netlink commands while passing data through l2tp sessions.Previous discussion on netdev determined that alternative solutions such as
spinlock writer synchronisation or per-cpu data would bring unjustified
overhead, given that most users interested in high volume traffic will likely
be running 64bit kernels on 64bit hardware.As such, this patch replaces l2tp's use of u64_stats with atomic_long_t,
thereby avoiding the deadlock.Ref:
http://marc.info/?l=linux-netdev&m=134029167910731&w=2
http://marc.info/?l=linux-netdev&m=134079868111131&w=2Signed-off-by: Tom Parkin
Signed-off-by: James Chapman
Signed-off-by: David S. Miller
