Commit Graph

207 Commits

Author SHA1 Message Date
Nicolas Rybowski 3764b0c565 mptcp: attach subflow socket to parent cgroup
It has been observed that the kernel sockets created for the subflows
(except the first one) are not in the same cgroup as their parents.
That's because the additional subflows are created by kernel workers.

This is a problem with eBPF programs attached to the parent's
cgroup won't be executed for the children. But also with any other features
of CGroup linked to a sk.

This patch fixes this behaviour.

As the subflow sockets are created by the kernel, we can't use
'mem_cgroup_sk_alloc' because of the current context being the one of the
kworker. This is why we have to do low level memcg manipulation, if
required.

Suggested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-14 17:30:06 -08:00
Linus Torvalds 9e4b0d55d8 Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
 "API:
   - Add speed testing on 1420-byte blocks for networking

  Algorithms:
   - Improve performance of chacha on ARM for network packets
   - Improve performance of aegis128 on ARM for network packets

  Drivers:
   - Add support for Keem Bay OCS AES/SM4
   - Add support for QAT 4xxx devices
   - Enable crypto-engine retry mechanism in caam
   - Enable support for crypto engine on sdm845 in qce
   - Add HiSilicon PRNG driver support"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (161 commits)
  crypto: qat - add capability detection logic in qat_4xxx
  crypto: qat - add AES-XTS support for QAT GEN4 devices
  crypto: qat - add AES-CTR support for QAT GEN4 devices
  crypto: atmel-i2c - select CONFIG_BITREVERSE
  crypto: hisilicon/trng - replace atomic_add_return()
  crypto: keembay - Add support for Keem Bay OCS AES/SM4
  dt-bindings: Add Keem Bay OCS AES bindings
  crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd
  crypto: seed - remove trailing semicolon in macro definition
  crypto: x86/poly1305 - Use TEST %reg,%reg instead of CMP $0,%reg
  crypto: x86/sha512 - Use TEST %reg,%reg instead of CMP $0,%reg
  crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg
  crypto: cpt - Fix sparse warnings in cptpf
  hwrng: ks-sa - Add dependency on IOMEM and OF
  crypto: lib/blake2s - Move selftest prototype into header file
  crypto: arm/aes-ce - work around Cortex-A57/A72 silion errata
  crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()
  crypto: ccree - rework cache parameters handling
  crypto: cavium - Use dma_set_mask_and_coherent to simplify code
  crypto: marvell/octeontx - Use dma_set_mask_and_coherent to simplify code
  ...
2020-12-14 12:18:19 -08:00
Paolo Abeni 0597d0f8e0 mptcp: plug subflow context memory leak
When a MPTCP listener socket is closed with unaccepted
children pending, the ULP release callback will be invoked,
but nobody will call into __mptcp_close_ssk() on the
corresponding subflow.

As a consequence, at ULP release time, the 'disposable' flag
will be cleared and the subflow context memory will be leaked.

This change addresses the issue always freeing the context if
the subflow is still in the accept queue at ULP release time.

Additionally, this fixes an incorrect code reference in the
related comment.

Note: this fix leverages the changes introduced by the previous
commit.

Fixes: e16163b6e2 ("mptcp: refactor shutdown and close")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-12-09 19:31:58 -08:00
Paolo Abeni 5b950ff433 mptcp: link MPC subflow into msk only after accept
Christoph reported the following splat:

WARNING: CPU: 0 PID: 4615 at net/ipv4/inet_connection_sock.c:1031 inet_csk_listen_stop+0x8e8/0xad0 net/ipv4/inet_connection_sock.c:1031
Modules linked in:
CPU: 0 PID: 4615 Comm: syz-executor.4 Not tainted 5.9.0 #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:inet_csk_listen_stop+0x8e8/0xad0 net/ipv4/inet_connection_sock.c:1031
Code: 03 00 00 00 e8 79 b2 3d ff e9 ad f9 ff ff e8 1f 76 ba fe be 02 00 00 00 4c 89 f7 e8 62 b2 3d ff e9 14 f9 ff ff e8 08 76 ba fe <0f> 0b e9 97 f8 ff ff e8 fc 75 ba fe be 03 00 00 00 4c 89 f7 e8 3f
RSP: 0018:ffffc900037f7948 EFLAGS: 00010293
RAX: ffff88810a349c80 RBX: ffff888114ee1b00 RCX: ffffffff827b14cd
RDX: 0000000000000000 RSI: ffffffff827b1c38 RDI: 0000000000000005
RBP: ffff88810a2a8000 R08: ffff88810a349c80 R09: fffff520006fef1f
R10: 0000000000000003 R11: fffff520006fef1e R12: ffff888114ee2d00
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888114ee1d68
FS:  00007f2ac1945700(0000) GS:ffff88811b400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd44798bc0 CR3: 0000000109810002 CR4: 0000000000170ef0
Call Trace:
 __tcp_close+0xd86/0x1110 net/ipv4/tcp.c:2433
 __mptcp_close_ssk+0x256/0x430 net/mptcp/protocol.c:1761
 __mptcp_destroy_sock+0x49b/0x770 net/mptcp/protocol.c:2127
 mptcp_close+0x62d/0x910 net/mptcp/protocol.c:2184
 inet_release+0xe9/0x1f0 net/ipv4/af_inet.c:434
 __sock_release+0xd2/0x280 net/socket.c:596
 sock_close+0x15/0x20 net/socket.c:1277
 __fput+0x276/0x960 fs/file_table.c:281
 task_work_run+0x109/0x1d0 kernel/task_work.c:151
 get_signal+0xe8f/0x1d40 kernel/signal.c:2561
 arch_do_signal+0x88/0x1b60 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0x9b/0xf0 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x22/0x150 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f2ac1254469
Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007f2ac1944dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffbf RBX: 000000000069bf00 RCX: 00007f2ac1254469
RDX: 0000000000000000 RSI: 0000000000008982 RDI: 0000000000000003
RBP: 000000000069bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000069bf0c
R13: 00007ffeb53f178f R14: 00000000004668b0 R15: 0000000000000003

After commit 0397c6d85f ("mptcp: keep unaccepted MPC subflow into
join list"), the msk's workqueue and/or PM can touch the MPC
subflow - and acquire its socket lock - even if it's still unaccepted.

If the above event races with the relevant listener socket close, we
can end-up with the above splat.

This change addresses the issue delaying the MPC socket insertion
in conn_list at accept time - that is, partially reverting the
blamed commit.

We must additionally ensure that mptcp_pm_fully_established()
happens after accept() time, or the PM will not be able to
handle properly such event - conn_list could be empty otherwise.

In the receive path, we check the subflow list node to ensure
it is out of the listener queue. Be sure client subflows do
not match transiently such condition moving them into the join
list earlier at creation time.

Since we now have multiple mptcp_pm_fully_established() call sites
from different code-paths, said helper can now race with itself.
Use an additional PM status bit to avoid multiple notifications.

Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/103
Fixes: 0397c6d85f ("mptcp: keep unaccepted MPC subflow into join list"),
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-12-09 19:31:58 -08:00
Florian Westphal 3ecfbe3e82 mptcp: emit tcp reset when a join request fails
RFC 8684 says:
 If the token is unknown or the host wants to refuse subflow establishment
 (for example, due to a limit on the number of subflows it will permit),
 the receiver will send back a reset (RST) signal, analogous to an unknown
 port in TCP, containing an MP_TCPRST option (Section 3.6) with an
 "MPTCP specific error" reason code.

mptcp-next doesn't support MP_TCPRST yet, this can be added in another
change.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-03 12:56:03 -08:00
Florian Westphal 7ea851d19b tcp: merge 'init_req' and 'route_req' functions
The Multipath-TCP standard (RFC 8684) says that an MPTCP host should send
a TCP reset if the token in a MP_JOIN request is unknown.

At this time we don't do this, the 3whs completes and the 'new subflow'
is reset afterwards.  There are two ways to allow MPTCP to send the
reset.

1. override 'send_synack' callback and emit the rst from there.
   The drawback is that the request socket gets inserted into the
   listeners queue just to get removed again right away.

2. Send the reset from the 'route_req' function instead.
   This avoids the 'add&remove request socket', but route_req lacks the
   skb that is required to send the TCP reset.

Instead of just adding the skb to that function for MPTCP sake alone,
Paolo suggested to merge init_req and route_req functions.

This saves one indirection from syn processing path and provides the skb
to the merged function at the same time.

'send reset on unknown mptcp join token' is added in next patch.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-03 12:56:03 -08:00
Paolo Abeni 6e628cd3a8 mptcp: use mptcp release_cb for delayed tasks
We have some tasks triggered by the subflow receive path
which require to access the msk socket status, specifically:
mptcp_clean_una() and mptcp_push_pending()

We have almost everything in place to defer to the msk
release_cb such tasks when the msk sock is owned.

Since the worker is no more used to clean the acked data,
for fallback sockets we need to explicitly flush them.

As an added bonus we can move the wake-up code in __mptcp_clean_una(),
simplify a lot mptcp_poll() and move the timer update under
the data lock.

The worker is now used only to process and send DATA_FIN
packets and do the mptcp-level retransmissions.

Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-30 17:55:23 -08:00
Jakub Kicinski 5c39f26e67 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Trivial conflict in CAN, keep the net-next + the byteswap wrapper.

Conflicts:
	drivers/net/can/usb/gs_usb.c

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-27 18:25:27 -08:00
Paolo Abeni d3ab78858f mptcp: fix NULL ptr dereference on bad MPJ
If an msk listener receives an MPJ carrying an invalid token, it
will zero the request socket msk entry. That should later
cause fallback and subflow reset - as per RFC - at
subflow_syn_recv_sock() time due to failing hmac validation.

Since commit 4cf8b7e48a ("subflow: introduce and use
mptcp_can_accept_new_subflow()"), we unconditionally dereference
- in mptcp_can_accept_new_subflow - the subflow request msk
before performing hmac validation. In the above scenario we
hit a NULL ptr dereference.

Address the issue doing the hmac validation earlier.

Fixes: 4cf8b7e48a ("subflow: introduce and use mptcp_can_accept_new_subflow()")
Tested-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Link: https://lore.kernel.org/r/03b2cfa3ac80d8fc18272edc6442a9ddf0b1e34e.1606400227.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-27 11:05:31 -08:00
Paolo Abeni ea4ca586b1 mptcp: refine MPTCP-level ack scheduling
Send timely MPTCP-level ack is somewhat difficult when
the insertion into the msk receive level is performed
by the worker.

It needs TCP-level dup-ack to notify the MPTCP-level
ack_seq increase, as both the TCP-level ack seq and the
rcv window are unchanged.

We can actually avoid processing incoming data with the
worker, and let the subflow or recevmsg() send ack as needed.

When recvmsg() moves the skbs inside the msk receive queue,
the msk space is still unchanged, so tcp_cleanup_rbuf() could
end-up skipping TCP-level ack generation. Anyway, when
__mptcp_move_skbs() is invoked, a known amount of bytes is
going to be consumed soon: we update rcv wnd computation taking
them in account.

Additionally we need to explicitly trigger tcp_cleanup_rbuf()
when recvmsg() consumes a significant amount of the receive buffer.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-20 15:33:25 -08:00
Paolo Abeni 0397c6d85f mptcp: keep unaccepted MPC subflow into join list
This will simplify all operation dealing with subflows
before accept time (e.g. data fin processing, add_addr).

The join list is already flushed by mptcp_stream_accept()
before returning the newly created msk to the user space.

This also fixes an potential bug present into the old code:
conn_list was manipulated without helding the msk lock
in mptcp_stream_accept().

Tested-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-20 15:33:25 -08:00
Eric Biggers a24d22b225 crypto: sha - split sha.h into sha1.h and sha2.h
Currently <crypto/sha.h> contains declarations for both SHA-1 and SHA-2,
and <crypto/sha3.h> contains declarations for SHA-3.

This organization is inconsistent, but more importantly SHA-1 is no
longer considered to be cryptographically secure.  So to the extent
possible, SHA-1 shouldn't be grouped together with any of the other SHA
versions, and usage of it should be phased out.

Therefore, split <crypto/sha.h> into two headers <crypto/sha1.h> and
<crypto/sha2.h>, and make everyone explicitly specify whether they want
the declarations for SHA-1, SHA-2, or both.

This avoids making the SHA-1 declarations visible to files that don't
want anything to do with SHA-1.  It also prepares for potentially moving
sha1.h into a new insecure/ or dangerous/ directory.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-11-20 14:45:33 +11:00
Florian Westphal 8edf08649e mptcp: rework poll+nospace handling
MPTCP maintains a status bit, MPTCP_SEND_SPACE, that is set when at
least one subflow and the mptcp socket itself are writeable.

mptcp_poll returns EPOLLOUT if the bit is set.

mptcp_sendmsg makes sure MPTCP_SEND_SPACE gets cleared when last write
has used up all subflows or the mptcp socket wmem.

This reworks nospace handling as follows:

MPTCP_SEND_SPACE is replaced with MPTCP_NOSPACE, i.e. inverted meaning.
This bit is set when the mptcp socket is not writeable.
The mptcp-level ack path schedule will then schedule the mptcp worker
to allow it to free already-acked data (and reduce wmem usage).

This will then wake userspace processes that wait for a POLLOUT event.

sendmsg will set MPTCP_NOSPACE only when it has to wait for more
wmem (blocking I/O case).

poll path will set MPTCP_NOSPACE in case the mptcp socket is
not writeable.

Normal tcp-level notification (SOCK_NOSPACE) is only enabled
in case the subflow socket has no available wmem.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-16 10:46:07 -08:00
Paolo Abeni e16163b6e2 mptcp: refactor shutdown and close
We must not close the subflows before all the MPTCP level
data, comprising the DATA_FIN has been acked at the MPTCP
level, otherwise we could be unable to retransmit as needed.

__mptcp_wr_shutdown() shutdown is responsible to check for the
correct status and close all subflows. Is called by the output
path after spooling any data and at shutdown/close time.

In a similar way, __mptcp_destroy_sock() is responsible to clean-up
the MPTCP level status, and is called when the msk transition
to TCP_CLOSE.

The protocol level close() does not force anymore the TCP_CLOSE
status, but orphan the msk socket and all the subflows.
Orphaned msk sockets are forciby closed after a timeout or
when all MPTCP-level data is acked.

There is a caveat about keeping the orphaned subflows around:
the TCP stack can asynchronusly call tcp_cleanup_ulp() on them via
tcp_close(). To prevent accessing freed memory on later MPTCP
level operations, the msk acquires a reference to each subflow
socket and prevent subflow_ulp_release() from releasing the
subflow context before __mptcp_destroy_sock().

The additional subflow references are released by __mptcp_done()
and the async ULP release is detected checking ULP ops. If such
field has been already cleared by the ULP release path, the
dangling context is freed directly by __mptcp_done().

Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-16 10:46:07 -08:00
Jakub Kicinski 2295cddf99 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Minor conflicts in net/mptcp/protocol.h and
tools/testing/selftests/net/Makefile.

In both cases code was added on both sides in the same place
so just keep both.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-15 12:43:21 -07:00
Paolo Abeni 0e4f35d788 mptcp: subflows garbage collection
The msk can close MP_JOIN subflows if the initial handshake
fails. Currently such subflows are kept alive in the
conn_list until the msk itself is closed.

Beyond the wasted memory, we could end-up sending the
DATA_FIN and the DATA_FIN ack on such socket, even after a
reset.

Fixes: 43b54c6ee3 ("mptcp: Use full MPTCP-level disconnect state machine")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-10 11:04:53 -07:00
Paolo Abeni d582484726 mptcp: fix fallback for MP_JOIN subflows
Additional/MP_JOIN subflows that do not pass some initial handshake
tests currently causes fallback to TCP. That is an RFC violation:
we should instead reset the subflow and leave the the msk untouched.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/91
Fixes: f296234c98 ("mptcp: Add handling of incoming MP_JOIN requests")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-10 11:04:53 -07:00
Davide Caratti 37198e93ce net: mptcp: make DACK4/DACK8 usage consistent among all subflows
using packetdrill it's possible to observe the same MPTCP DSN being acked
by different subflows with DACK4 and DACK8. This is in contrast with what
specified in RFC8684 §3.3.2: if an MPTCP endpoint transmits a 64-bit wide
DSN, it MUST be acknowledged with a 64-bit wide DACK. Fix 'use_64bit_ack'
variable to make it a property of MPTCP sockets, not TCP subflows.

Fixes: a0c1d0eafd ("mptcp: Use 32-bit DATA_ACK when possible")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-09 08:25:48 -07:00
Jakub Kicinski 9d49aea13f Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Small conflict around locking in rxrpc_process_event() -
channel_lock moved to bundle in next, while state lock
needs _bh() from net.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-08 15:44:50 -07:00
Paolo Abeni 017512a07e mptcp: more DATA FIN fixes
Currently data fin on data packet are not handled properly:
the 'rcv_data_fin_seq' field is interpreted as the last
sequence number carrying a valid data, but for data fin
packet with valid maps we currently store map_seq + map_len,
that is, the next value.

The 'write_seq' fields carries instead the value subseguent
to the last valid byte, so in mptcp_write_data_fin() we
never detect correctly the last DSS map.

Fixes: 7279da6145 ("mptcp: Use MPTCP-level flag for sending DATA_FIN")
Fixes: 1a49b2c2a5 ("mptcp: Handle incoming 32-bit DATA_FIN values")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-06 06:06:59 -07:00
David S. Miller 8b0308fe31 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Rejecting non-native endian BTF overlapped with the addition
of support for it.

The rest were more simple overlapping changes, except the
renesas ravb binding update, which had to follow a file
move as well as a YAML conversion.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-05 18:40:01 -07:00
Mat Martineau 1a49b2c2a5 mptcp: Handle incoming 32-bit DATA_FIN values
The peer may send a DATA_FIN mapping with either a 32-bit or 64-bit
sequence number. When a 32-bit sequence number is received for the
DATA_FIN, it must be expanded to 64 bits before comparing it to the
last acked sequence number. This expansion was missing.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/93
Fixes: 3721b9b646 ("mptcp: Track received DATA_FIN sequence number and add related helpers")
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-29 18:15:46 -07:00
Geliang Tang 5c8c164095 mptcp: add mptcp_destroy_common helper
This patch added a new helper named mptcp_destroy_common containing the
shared code between mptcp_destroy() and mptcp_sock_destruct().

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-24 19:58:34 -07:00
Geliang Tang b6c0838086 mptcp: remove addr and subflow in PM netlink
This patch implements the remove announced addr and subflow logic in PM
netlink.

When the PM netlink removes an address, we traverse all the existing msk
sockets to find the relevant sockets.

We add a new list named anno_list in mptcp_pm_data, to record all the
announced addrs. In the traversing, we check if it has been recorded.
If it has been, we trigger the RM_ADDR signal.

We also check if this address is in conn_list. If it is, we remove the
subflow which using this local address.

Since we call mptcp_pm_free_anno_list in mptcp_destroy, we need to move
__mptcp_init_sock before the mptcp_is_enabled check in mptcp_init_sock.

Suggested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Suggested-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-24 19:58:33 -07:00
Mat Martineau ef59b1953c mptcp: Wake up MPTCP worker when DATA_FIN found on a TCP FIN packet
When receiving a DATA_FIN MPTCP option on a TCP FIN packet, the DATA_FIN
information would be stored but the MPTCP worker did not get
scheduled. In turn, the MPTCP socket state would remain in
TCP_ESTABLISHED and no blocked operations would be awakened.

TCP FIN packets are seen by the MPTCP socket when moving skbs out of the
subflow receive queues, so schedule the MPTCP worker when a skb with
DATA_FIN but no data payload is moved from a subflow queue. Other cases
(DATA_FIN on a bare TCP ACK or on a packet with data payload) are
already handled.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/84
Fixes: 43b54c6ee3 ("mptcp: Use full MPTCP-level disconnect state machine")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-23 17:30:52 -07:00
David S. Miller 3ab0a7a0c3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Two minor conflicts:

1) net/ipv4/route.c, adding a new local variable while
   moving another local variable and removing it's
   initial assignment.

2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes.
   One pretty prints the port mode differently, whilst another
   changes the driver to try and obtain the port mode from
   the port node rather than the switch node.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-22 16:45:34 -07:00
Paolo Abeni 1d39cd8cf7 mptcp: fix integer overflow in mptcp_subflow_discard_data()
Christoph reported an infinite loop in the subflow receive path
under stress condition.

If there are multiple subflows, each of them using a large send
buffer, the delta between the sequence number used by
MPTCP-level retransmission can and the current msk->ack_seq
can be greater than MAX_INT.

In the above scenario, when calling mptcp_subflow_discard_data(),
such delta will be truncated to int, and could result in a negative
number: no bytes will be dropped, and subflow_check_data_avail()
will try again to process the same packet, looping forever.

This change addresses the issue by expanding the 'limit' size to 64
bits, so that overflows are not possible anymore.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/87
Fixes: 6719331c2f ("mptcp: trigger msk processing even for OoO data")
Reported-and-tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-17 18:04:48 -07:00
Paolo Abeni c76c695656 mptcp: call tcp_cleanup_rbuf on subflows
That is needed to let the subflows announce promptly when new
space is available in the receive buffer.

tcp_cleanup_rbuf() is currently a static function, drop the
scope modifier and add a declaration in the TCP header.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 4596a2c1b7 mptcp: allow creating non-backup subflows
Currently the 'backup' attribute of local endpoint
is ignored. Let's use it for the MP_JOIN handshake

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni ef0da3b8a2 mptcp: move address attribute into mptcp_addr_info
So that can be accessed easily from the subflow creation
helper. No functional change intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 06242e44b9 mptcp: add OoO related mibs
Add a bunch of MPTCP mibs related to MPTCP OoO data
processing.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 04e4cd4f7c mptcp: cleanup mptcp_subflow_discard_data()
There is no need to use the tcp_read_sock(), we can
simply drop the skb. Additionally try to look at the
next buffer for in order data.

This both simplifies the code and avoid unneeded indirect
calls.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni ab174ad8ef mptcp: move ooo skbs into msk out of order queue.
Add an RB-tree to cope with OoO (at MPTCP level) data.
__mptcp_move_skb() insert into the RB tree "future"
data, eventually coalescing skb as allowed by the
MPTCP DSN.

To simplify sequence accounting, move the DSN inside
the cb.

After successfully enqueuing in sequence data, check
if we can use any data from the RB tree.

Additionally move the data_fin check after spooling
data from the OoO tree, otherwise we could miss shutdown
events.

The RB tree code is copied as verbatim as possible
from tcp_data_queue_ofo(), with a few simplifications
due to the fact that MPTCP doesn't need to cope with
sacks. All bugs here are added by me.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 6719331c2f mptcp: trigger msk processing even for OoO data
This is a prerequisite to allow receiving data from multiple
subflows without re-injection.

Instead of dropping the OoO - "future" data in
subflow_check_data_avail(), call into __mptcp_move_skbs()
and let the msk drop that.

To avoid code duplication factor out the mptcp_subflow_discard_data()
helper.

Note that __mptcp_move_skbs() can now find multiple subflows
with data avail (comprising to-be-discarded data), so must
update the byte counter incrementally.

v1 -> v2:
 - fix checkpatch issues (unsigned -> unsigned int)

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 47bebdf365 mptcp: set data_ready status bit in subflow_check_data_avail()
This simplify mptcp_subflow_data_available() and will
made follow-up patches simpler.

Additionally remove the unneeded checks on subflow copied_seq:
we always whole skbs out of subflows.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Paolo Abeni 63561a403c mptcp: rethink 'is writable' conditional
Currently, when checking for the 'msk is writable' condition, we
look at the individual subflows write space.
That works well while we send data via a single subflow, but will
not as soon as we will enable concurrent xmit on multiple subflows.

With this change msk becomes writable when the following conditions
hold:
- the socket has some free write space
- there is at least a subflow with write free space

Additionally we need to set the NOSPACE bit on all subflows
before blocking.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14 13:28:02 -07:00
Geliang Tang 2ff0e566fa mptcp: fix subflow's remote_id issues
This patch set the init remote_id to zero, otherwise it will be a random
number.

Then it added the missing subflow's remote_id setting code both in
__mptcp_subflow_connect and in subflow_ulp_clone.

Fixes: 01cacb00b3 ("mptcp: add netlink-based PM")
Fixes: ec3edaa7ca ("mptcp: Add handling of outgoing MP_JOIN requests")
Fixes: f296234c98 ("mptcp: Add handling of incoming MP_JOIN requests")
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10 12:29:15 -07:00
Paolo Abeni 7ee2492635 mptcp: fix warn at shutdown time for unaccepted msk sockets
With commit b93df08ccd ("mptcp: explicitly track the fully
established status"), the status of unaccepted mptcp closed in
mptcp_sock_destruct() changes from TCP_SYN_RECV to TCP_ESTABLISHED.

As a result mptcp_sock_destruct() does not perform the proper
cleanup and inet_sock_destruct() will later emit a warn.

Address the issue updating the condition tested in mptcp_sock_destruct().
Also update the related comment.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/66
Reported-and-tested-by: Christoph Paasch <cpaasch@apple.com>
Fixes: b93df08ccd ("mptcp: explicitly track the fully established status")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-07 17:26:16 -07:00
Paolo Abeni adf7341064 mptcp: be careful on subflow creation
Nicolas reported the following oops:

[ 1521.392541] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 1521.394189] #PF: supervisor read access in kernel mode
[ 1521.395376] #PF: error_code(0x0000) - not-present page
[ 1521.396607] PGD 0 P4D 0
[ 1521.397156] Oops: 0000 [#1] SMP PTI
[ 1521.398020] CPU: 0 PID: 22986 Comm: kworker/0:2 Not tainted 5.8.0-rc4+ #109
[ 1521.399618] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 1521.401728] Workqueue: events mptcp_worker
[ 1521.402651] RIP: 0010:mptcp_subflow_create_socket+0xf1/0x1c0
[ 1521.403954] Code: 24 08 89 44 24 04 48 8b 7a 18 e8 2a 48 d4 ff 8b 44 24 04 85 c0 75 7a 48 8b 8b 78 02 00 00 48 8b 54 24 08 48 8d bb 80 00 00 00 <48> 8b 89 c0 00 00 00 48 89 8a c0 00 00 00 48 8b 8b 78 02 00 00 8b
[ 1521.408201] RSP: 0000:ffffabc4002d3c60 EFLAGS: 00010246
[ 1521.409433] RAX: 0000000000000000 RBX: ffffa0b9ad8c9a00 RCX: 0000000000000000
[ 1521.411096] RDX: ffffa0b9ae78a300 RSI: 00000000fffffe01 RDI: ffffa0b9ad8c9a80
[ 1521.412734] RBP: ffffa0b9adff2e80 R08: ffffa0b9af02d640 R09: ffffa0b9ad923a00
[ 1521.414333] R10: ffffabc4007139f8 R11: fefefefefefefeff R12: ffffabc4002d3cb0
[ 1521.415918] R13: ffffa0b9ad91fa58 R14: ffffa0b9ad8c9f9c R15: 0000000000000000
[ 1521.417592] FS:  0000000000000000(0000) GS:ffffa0b9af000000(0000) knlGS:0000000000000000
[ 1521.419490] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1521.420839] CR2: 00000000000000c0 CR3: 000000002951e006 CR4: 0000000000160ef0
[ 1521.422511] Call Trace:
[ 1521.423103]  __mptcp_subflow_connect+0x94/0x1f0
[ 1521.425376]  mptcp_pm_create_subflow_or_signal_addr+0x200/0x2a0
[ 1521.426736]  mptcp_worker+0x31b/0x390
[ 1521.431324]  process_one_work+0x1fc/0x3f0
[ 1521.432268]  worker_thread+0x2d/0x3b0
[ 1521.434197]  kthread+0x117/0x130
[ 1521.435783]  ret_from_fork+0x22/0x30

on some unconventional configuration.

The MPTCP protocol is trying to create a subflow for an
unaccepted server socket. That is allowed by the RFC, even
if subflow creation will likely fail.
Unaccepted sockets have still a NULL sk_socket field,
avoid the issue by failing earlier.

Reported-and-tested-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Fixes: 7d14b0d2b9 ("mptcp: set correct vfs info for subflows")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-05 12:24:20 -07:00
Florian Westphal 9466a1cceb mptcp: enable JOIN requests even if cookies are in use
JOIN requests do not work in syncookie mode -- for HMAC validation, the
peers nonce and the mptcp token (to obtain the desired connection socket
the join is for) are required, but this information is only present in the
initial syn.

So either we need to drop all JOIN requests once a listening socket enters
syncookie mode, or we need to store enough state to reconstruct the request
socket later.

This adds a state table (1024 entries) to store the data present in the
MP_JOIN syn request and the random nonce used for the cookie syn/ack.

When a MP_JOIN ACK passed cookie validation, the table is consulted
to rebuild the request socket from it.

An alternate approach would be to "cancel" syn-cookie mode and force
MP_JOIN to always use a syn queue entry.

However, doing so brings the backlog over the configured queue limit.

v2: use req->syncookie, not (removed) want_cookie arg

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-31 16:55:32 -07:00
Florian Westphal c83a47e50d mptcp: subflow: add mptcp_subflow_init_cookie_req helper
Will be used to initialize the mptcp request socket when a MP_CAPABLE
request was handled in syncookie mode, i.e. when a TCP ACK containing a
MP_CAPABLE option is a valid syncookie value.

Normally (non-cookie case), MPTCP will generate a unique 32 bit connection
ID and stores it in the MPTCP token storage to be able to retrieve the
mptcp socket for subflow joining.

In syncookie case, we do not want to store any state, so just generate the
unique ID and use it in the reply.

This means there is a small window where another connection could generate
the same token.

When Cookie ACK comes back, we check that the token has not been registered
in the mean time.  If it was, the connection needs to fall back to TCP.

Changes in v2:
 - use req->syncookie instead of passing 'want_cookie' arg to ->init_req()
   (Eric Dumazet)

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-31 16:55:32 -07:00
Florian Westphal 08b8d08098 mptcp: rename and export mptcp_subflow_request_sock_ops
syncookie code path needs to create an mptcp request sock.

Prepare for this and add mptcp prefix plus needed export of ops struct.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-31 16:55:32 -07:00
Florian Westphal 78d8b7bc4b mptcp: subflow: split subflow_init_req
When syncookie support is added, we will need to add a variant of
subflow_init_req() helper.  It will do almost same thing except
that it will not compute/add a token to the mptcp token tree.

To avoid excess copy&paste, this commit splits away part of the
code into a new helper, __subflow_init_req, that can then be re-used
from the 'no insert' function added in a followup change.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-31 16:55:32 -07:00
Florian Westphal 535fb8152f mptcp: token: move retry to caller
Once syncookie support is added, no state will be stored anymore when the
syn/ack is generated in syncookie mode.

When the ACK comes back, the generated key will be taken from the TCP ACK,
the token is re-generated and inserted into the token tree.

This means we can't retry with a new key when the token is already taken
in the syncookie case.

Therefore, move the retry logic to the caller to prepare for syncookie
support in mptcp.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-31 16:55:32 -07:00
Mat Martineau 067a0b3dc5 mptcp: Only use subflow EOF signaling on fallback connections
The MPTCP state machine handles disconnections on non-fallback connections,
but the mptcp_sock still needs to get notified when fallback subflows
disconnect.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-28 17:02:42 -07:00
Mat Martineau 43b54c6ee3 mptcp: Use full MPTCP-level disconnect state machine
RFC 8684 appendix D describes the connection state machine for
MPTCP. This patch implements the DATA_FIN / DATA_ACK exchanges and
MPTCP-level socket state changes described in that appendix, rather than
simply sending DATA_FIN along with TCP FIN when disconnecting subflows.

DATA_FIN is now sent and acknowledged before shutting down the
subflows. Received DATA_FIN information (if not part of a data packet)
is written to the MPTCP socket when the incoming DSS option is parsed by
the subflow, and the MPTCP worker is scheduled to process the
flag. DATA_FIN received as part of a full DSS mapping will be handled
when the mapping is processed.

The DATA_FIN is acknowledged by the worker if the reader is caught
up. If there is still data to be moved to the MPTCP-level queue, ack_seq
will be incremented to account for the DATA_FIN when it reaches the end
of the stream and a DATA_ACK will be sent to the peer.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-28 17:02:42 -07:00
Paolo Abeni 4cf8b7e48a subflow: introduce and use mptcp_can_accept_new_subflow()
So that we can easily perform some basic PM-related
adimission checks before creating the child socket.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:25 -07:00
Paolo Abeni 97e617518c subflow: use rsk_ops->send_reset()
tcp_send_active_reset() is more prone to transient errors
(memory allocation or xmit queue full): in stress conditions
the kernel may drop the egress packet, and the client will be
stuck.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:25 -07:00
Paolo Abeni b7514694ed subflow: explicitly check for plain tcp rsk
When syncookie are in use, the TCP stack may feed into
subflow_syn_recv_sock() plain TCP request sockets. We can't
access mptcp_subflow_request_sock-specific fields on such
sockets. Explicitly check the rsk ops to do safe accesses.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:25 -07:00
Paolo Abeni fa25e815d9 mptcp: cleanup subflow_finish_connect()
The mentioned function has several unneeded branches,
handle each case - MP_CAPABLE, MP_JOIN, fallback -
under a single conditional and drop quite a bit of
duplicate code.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:24 -07:00
Paolo Abeni b93df08ccd mptcp: explicitly track the fully established status
Currently accepted msk sockets become established only after
accept() returns the new sk to user-space.

As MP_JOIN request are refused as per RFC spec on non fully
established socket, the above causes mp_join self-tests
instabilities.

This change lets the msk entering the established status
as soon as it receives the 3rd ack and propagates the first
subflow fully established status on the msk socket.

Finally we can change the subflow acceptance condition to
take in account both the sock state and the msk fully
established flag.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:24 -07:00
Paolo Abeni b0977bb268 subflow: always init 'rel_write_seq'
Currently we do not init the subflow write sequence for
MP_JOIN subflows. This will cause bad mapping being
generated as soon as we will use non backup subflow.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-23 11:47:24 -07:00
Davide Caratti 8c72894048 mptcp: silence warning in subflow_data_ready()
since commit d47a721520 ("mptcp: fix race in subflow_data_ready()"), it
is possible to observe a regression in MP_JOIN kselftests. For sockets in
TCP_CLOSE state, it's not sufficient to just wake up the main socket: we
also need to ensure that received data are made available to the reader.
Silence the WARN_ON_ONCE() in these cases: it preserves the syzkaller fix
and restores kselftests	when they are ran as follows:

  # while true; do
  > make KBUILD_OUTPUT=/tmp/kselftest TARGETS=net/mptcp kselftest
  > done

Reported-by: Florian Westphal <fw@strlen.de>
Fixes: d47a721520 ("mptcp: fix race in subflow_data_ready()")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/47
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-17 12:47:00 -07:00
Davide Caratti d47a721520 mptcp: fix race in subflow_data_ready()
syzkaller was able to make the kernel reach subflow_data_ready() for a
server subflow that was closed before subflow_finish_connect() completed.
In these cases we can avoid using the path for regular/fallback MPTCP
data, and just wake the main socket, to avoid the following warning:

 WARNING: CPU: 0 PID: 9370 at net/mptcp/subflow.c:885
 subflow_data_ready+0x1e6/0x290 net/mptcp/subflow.c:885
 Kernel panic - not syncing: panic_on_warn set ...
 CPU: 0 PID: 9370 Comm: syz-executor.0 Not tainted 5.7.0 #106
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
 rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
 Call Trace:
  <IRQ>
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0xb7/0xfe lib/dump_stack.c:118
  panic+0x29e/0x692 kernel/panic.c:221
  __warn.cold+0x2f/0x3d kernel/panic.c:582
  report_bug+0x28b/0x2f0 lib/bug.c:195
  fixup_bug arch/x86/kernel/traps.c:105 [inline]
  fixup_bug arch/x86/kernel/traps.c:100 [inline]
  do_error_trap+0x10f/0x180 arch/x86/kernel/traps.c:197
  do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:216
  invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:1027
 RIP: 0010:subflow_data_ready+0x1e6/0x290 net/mptcp/subflow.c:885
 Code: 04 02 84 c0 74 06 0f 8e 91 00 00 00 41 0f b6 5e 48 31 ff 83 e3 18
 89 de e8 37 ec 3d fe 84 db 0f 85 65 ff ff ff e8 fa ea 3d fe <0f> 0b e9
 59 ff ff ff e8 ee ea 3d fe 48 89 ee 4c 89 ef e8 f3 77 ff
 RSP: 0018:ffff88811b2099b0 EFLAGS: 00010206
 RAX: ffff888111197000 RBX: 0000000000000000 RCX: ffffffff82fbc609
 RDX: 0000000000000100 RSI: ffffffff82fbc616 RDI: 0000000000000001
 RBP: ffff8881111bc800 R08: ffff888111197000 R09: ffffed10222a82af
 R10: ffff888111541577 R11: ffffed10222a82ae R12: 1ffff11023641336
 R13: ffff888111541000 R14: ffff88810fd4ca00 R15: ffff888111541570
  tcp_child_process+0x754/0x920 net/ipv4/tcp_minisocks.c:841
  tcp_v4_do_rcv+0x749/0x8b0 net/ipv4/tcp_ipv4.c:1642
  tcp_v4_rcv+0x2666/0x2e60 net/ipv4/tcp_ipv4.c:1999
  ip_protocol_deliver_rcu+0x29/0x1f0 net/ipv4/ip_input.c:204
  ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline]
  NF_HOOK include/linux/netfilter.h:421 [inline]
  ip_local_deliver+0x2da/0x390 net/ipv4/ip_input.c:252
  dst_input include/net/dst.h:441 [inline]
  ip_rcv_finish net/ipv4/ip_input.c:428 [inline]
  ip_rcv_finish net/ipv4/ip_input.c:414 [inline]
  NF_HOOK include/linux/netfilter.h:421 [inline]
  ip_rcv+0xef/0x140 net/ipv4/ip_input.c:539
  __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:5268
  __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5382
  process_backlog+0x1e5/0x6d0 net/core/dev.c:6226
  napi_poll net/core/dev.c:6671 [inline]
  net_rx_action+0x3e3/0xd70 net/core/dev.c:6739
  __do_softirq+0x18c/0x634 kernel/softirq.c:292
  do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
  </IRQ>
  do_softirq.part.0+0x26/0x30 kernel/softirq.c:337
  do_softirq arch/x86/include/asm/preempt.h:26 [inline]
  __local_bh_enable_ip+0x46/0x50 kernel/softirq.c:189
  local_bh_enable include/linux/bottom_half.h:32 [inline]
  rcu_read_unlock_bh include/linux/rcupdate.h:723 [inline]
  ip_finish_output2+0x78a/0x19c0 net/ipv4/ip_output.c:229
  __ip_finish_output+0x471/0x720 net/ipv4/ip_output.c:306
  dst_output include/net/dst.h:435 [inline]
  ip_local_out+0x181/0x1e0 net/ipv4/ip_output.c:125
  __ip_queue_xmit+0x7a1/0x14e0 net/ipv4/ip_output.c:530
  __tcp_transmit_skb+0x19dc/0x35e0 net/ipv4/tcp_output.c:1238
  __tcp_send_ack.part.0+0x3c2/0x5b0 net/ipv4/tcp_output.c:3785
  __tcp_send_ack net/ipv4/tcp_output.c:3791 [inline]
  tcp_send_ack+0x7d/0xa0 net/ipv4/tcp_output.c:3791
  tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6040 [inline]
  tcp_rcv_state_process+0x36a4/0x49c2 net/ipv4/tcp_input.c:6209
  tcp_v4_do_rcv+0x343/0x8b0 net/ipv4/tcp_ipv4.c:1651
  sk_backlog_rcv include/net/sock.h:996 [inline]
  __release_sock+0x1ad/0x310 net/core/sock.c:2548
  release_sock+0x54/0x1a0 net/core/sock.c:3064
  inet_wait_for_connect net/ipv4/af_inet.c:594 [inline]
  __inet_stream_connect+0x57e/0xd50 net/ipv4/af_inet.c:686
  inet_stream_connect+0x53/0xa0 net/ipv4/af_inet.c:725
  mptcp_stream_connect+0x171/0x5f0 net/mptcp/protocol.c:1920
  __sys_connect_file net/socket.c:1854 [inline]
  __sys_connect+0x267/0x2f0 net/socket.c:1871
  __do_sys_connect net/socket.c:1882 [inline]
  __se_sys_connect net/socket.c:1879 [inline]
  __x64_sys_connect+0x6f/0xb0 net/socket.c:1879
  do_syscall_64+0xb7/0x3d0 arch/x86/entry/common.c:295
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7fb577d06469
 Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89
 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
 RSP: 002b:00007fb5783d5dd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
 RAX: ffffffffffffffda RBX: 000000000068bfa0 RCX: 00007fb577d06469
 RDX: 000000000000004d RSI: 0000000020000040 RDI: 0000000000000003
 RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
 R13: 000000000041427c R14: 00007fb5783d65c0 R15: 0000000000000003

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/39
Reported-by: Christoph Paasch <cpaasch@apple.com>
Fixes: e1ff9e82e2 ("net: mptcp: improve fallback to TCP")
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-06 13:31:12 -07:00
Florian Westphal a6b118febb mptcp: add receive buffer auto-tuning
When mptcp is used, userspace doesn't read from the tcp (subflow)
socket but from the parent (mptcp) socket receive queue.

skbs are moved from the subflow socket to the mptcp rx queue either from
'data_ready' callback (if mptcp socket can be locked), a work queue, or
the socket receive function.

This means tcp_rcv_space_adjust() is never called and thus no receive
buffer size auto-tuning is done.

An earlier (not merged) patch added tcp_rcv_space_adjust() calls to the
function that moves skbs from subflow to mptcp socket.
While this enabled autotuning, it also meant tuning was done even if
userspace was reading the mptcp socket very slowly.

This adds mptcp_rcv_space_adjust() and calls it after userspace has
read data from the mptcp socket rx queue.

Its very similar to tcp_rcv_space_adjust, with two differences:

1. The rtt estimate is the largest one observed on a subflow
2. The rcvbuf size and window clamp of all subflows is adjusted
   to the mptcp-level rcvbuf.

Otherwise, we get spurious drops at tcp (subflow) socket level if
the skbs are not moved to the mptcp socket fast enough.

Before:
time mptcp_connect.sh -t -f $((4*1024*1024)) -d 300 -l 0.01% -r 0 -e "" -m mmap
[..]
ns4 MPTCP -> ns3 (10.0.3.2:10108      ) MPTCP   (duration 40823ms) [ OK ]
ns4 MPTCP -> ns3 (10.0.3.2:10109      ) TCP     (duration 23119ms) [ OK ]
ns4 TCP   -> ns3 (10.0.3.2:10110      ) MPTCP   (duration  5421ms) [ OK ]
ns4 MPTCP -> ns3 (dead:beef:3::2:10111) MPTCP   (duration 41446ms) [ OK ]
ns4 MPTCP -> ns3 (dead:beef:3::2:10112) TCP     (duration 23427ms) [ OK ]
ns4 TCP   -> ns3 (dead:beef:3::2:10113) MPTCP   (duration  5426ms) [ OK ]
Time: 1396 seconds

After:
ns4 MPTCP -> ns3 (10.0.3.2:10108      ) MPTCP   (duration  5417ms) [ OK ]
ns4 MPTCP -> ns3 (10.0.3.2:10109      ) TCP     (duration  5427ms) [ OK ]
ns4 TCP   -> ns3 (10.0.3.2:10110      ) MPTCP   (duration  5422ms) [ OK ]
ns4 MPTCP -> ns3 (dead:beef:3::2:10111) MPTCP   (duration  5415ms) [ OK ]
ns4 MPTCP -> ns3 (dead:beef:3::2:10112) TCP     (duration  5422ms) [ OK ]
ns4 TCP   -> ns3 (dead:beef:3::2:10113) MPTCP   (duration  5423ms) [ OK ]
Time: 296 seconds

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-01 17:47:55 -07:00
Paolo Abeni 6bad912b7e mptcp: do nonce initialization at subflow creation time
This clean-up the code a bit, reduces the number of
used hooks and indirect call requested, and allow
better error reporting from __mptcp_subflow_connect()

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-30 13:38:00 -07:00
Davide Caratti 8fd738049a mptcp: fallback in case of simultaneous connect
when a MPTCP client tries to connect to itself, tcp_finish_connect() is
never reached. Because of this, depending on the socket current state,
multiple faulty behaviours can be observed:

1) a WARN_ON() in subflow_data_ready() is hit
 WARNING: CPU: 2 PID: 882 at net/mptcp/subflow.c:911 subflow_data_ready+0x18b/0x230
 [...]
 CPU: 2 PID: 882 Comm: gh35 Not tainted 5.7.0+ #187
 [...]
 RIP: 0010:subflow_data_ready+0x18b/0x230
 [...]
 Call Trace:
  tcp_data_queue+0xd2f/0x4250
  tcp_rcv_state_process+0xb1c/0x49d3
  tcp_v4_do_rcv+0x2bc/0x790
  __release_sock+0x153/0x2d0
  release_sock+0x4f/0x170
  mptcp_shutdown+0x167/0x4e0
  __sys_shutdown+0xe6/0x180
  __x64_sys_shutdown+0x50/0x70
  do_syscall_64+0x9a/0x370
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

2) client is stuck forever in mptcp_sendmsg() because the socket is not
   TCP_ESTABLISHED

 crash> bt 4847
 PID: 4847   TASK: ffff88814b2fb100  CPU: 1   COMMAND: "gh35"
  #0 [ffff8881376ff680] __schedule at ffffffff97248da4
  #1 [ffff8881376ff778] schedule at ffffffff9724a34f
  #2 [ffff8881376ff7a0] schedule_timeout at ffffffff97252ba0
  #3 [ffff8881376ff8a8] wait_woken at ffffffff958ab4ba
  #4 [ffff8881376ff940] sk_stream_wait_connect at ffffffff96c2d859
  #5 [ffff8881376ffa28] mptcp_sendmsg at ffffffff97207fca
  #6 [ffff8881376ffbc0] sock_sendmsg at ffffffff96be1b5b
  #7 [ffff8881376ffbe8] sock_write_iter at ffffffff96be1daa
  #8 [ffff8881376ffce8] new_sync_write at ffffffff95e5cb52
  #9 [ffff8881376ffe50] vfs_write at ffffffff95e6547f
 #10 [ffff8881376ffe90] ksys_write at ffffffff95e65d26
 #11 [ffff8881376fff28] do_syscall_64 at ffffffff956088ba
 #12 [ffff8881376fff50] entry_SYSCALL_64_after_hwframe at ffffffff9740008c
     RIP: 00007f126f6956ed  RSP: 00007ffc2a320278  RFLAGS: 00000217
     RAX: ffffffffffffffda  RBX: 0000000020000044  RCX: 00007f126f6956ed
     RDX: 0000000000000004  RSI: 00000000004007b8  RDI: 0000000000000003
     RBP: 00007ffc2a3202a0   R8: 0000000000400720   R9: 0000000000400720
     R10: 0000000000400720  R11: 0000000000000217  R12: 00000000004004b0
     R13: 00007ffc2a320380  R14: 0000000000000000  R15: 0000000000000000
     ORIG_RAX: 0000000000000001  CS: 0033  SS: 002b

3) tcpdump captures show that DSS is exchanged even when MP_CAPABLE handshake
   didn't complete.

 $ tcpdump -tnnr bad.pcap
 IP 127.0.0.1.20000 > 127.0.0.1.20000: Flags [S], seq 3208913911, win 65483, options [mss 65495,sackOK,TS val 3291706876 ecr 3291694721,nop,wscale 7,mptcp capable v1], length 0
 IP 127.0.0.1.20000 > 127.0.0.1.20000: Flags [S.], seq 3208913911, ack 3208913912, win 65483, options [mss 65495,sackOK,TS val 3291706876 ecr 3291706876,nop,wscale 7,mptcp capable v1], length 0
 IP 127.0.0.1.20000 > 127.0.0.1.20000: Flags [.], ack 1, win 512, options [nop,nop,TS val 3291706876 ecr 3291706876], length 0
 IP 127.0.0.1.20000 > 127.0.0.1.20000: Flags [F.], seq 1, ack 1, win 512, options [nop,nop,TS val 3291707876 ecr 3291706876,mptcp dss fin seq 0 subseq 0 len 1,nop,nop], length 0
 IP 127.0.0.1.20000 > 127.0.0.1.20000: Flags [.], ack 2, win 512, options [nop,nop,TS val 3291707876 ecr 3291707876], length 0

force a fallback to TCP in these cases, and adjust the main socket
state to avoid hanging in mptcp_sendmsg().

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/35
Reported-by: Christoph Paasch <cpaasch@apple.com>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-29 17:29:38 -07:00
Davide Caratti e1ff9e82e2 net: mptcp: improve fallback to TCP
Keep using MPTCP sockets and a use "dummy mapping" in case of fallback
to regular TCP. When fallback is triggered, skip addition of the MPTCP
option on send.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/11
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/22
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-29 17:29:38 -07:00
Paolo Abeni 2c5ebd001d mptcp: refactor token container
Replace the radix tree with a hash table allocated
at boot time. The radix tree has some shortcoming:
a single lock is contented by all the mptcp operation,
the lookup currently use such lock, and traversing
all the items would require a lock, too.

With hash table instead we trade a little memory to
address all the above - a per bucket lock is used.

To hash the MPTCP sockets, we re-use the msk' sk_node
entry: the MPTCP sockets are never hashed by the stack.
Replace the existing hash proto callbacks with a dummy
implementation, annotating the above constraint.

Additionally refactor the token creation to code to:

- limit the number of consecutive attempts to a fixed
maximum. Hitting a hash bucket with a long chain is
considered a failed attempt

- accept() no longer can fail to token management.

- if token creation fails at connect() time, we do
fallback to TCP (before the connection was closed)

v1 -> v2:
 - fix "no newline at end of file" - Jakub

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-26 16:21:39 -07:00
Paolo Abeni d39dceca38 mptcp: add __init annotation on setup functions
Add the missing annotation in some setup-only
functions.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-26 16:21:39 -07:00
Paolo Abeni 9e365ff576 mptcp: drop MP_JOIN request sock on syn cookies
Currently any MPTCP socket using syn cookies will fallback to
TCP at 3rd ack time. In case of MP_JOIN requests, the RFC mandate
closing the child and sockets, but the existing error paths
do not handle the syncookie scenario correctly.

Address the issue always forcing the child shutdown in case of
MP_JOIN fallback.

Fixes: ae2dd71649 ("mptcp: handle tcp fallback when using syn cookies")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-18 20:25:51 -07:00
Paolo Abeni 8fd4de1275 mptcp: cache msk on MP_JOIN init_req
The msk ownership is transferred to the child socket at
3rd ack time, so that we avoid more lookups later. If the
request does not reach the 3rd ack, the MSK reference is
dropped at request sock release time.

As a side effect, fallback is now tracked by a NULL msk
reference instead of zeroed 'mp_join' field. This will
simplify the next patch.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-18 20:25:51 -07:00
Wei Yongjun b8ad540dd4 mptcp: fix memory leak in mptcp_subflow_create_socket()
socket malloced  by sock_create_kern() should be release before return
in the error handling, otherwise it cause memory leak.

unreferenced object 0xffff88810910c000 (size 1216):
  comm "00000003_test_m", pid 12238, jiffies 4295050289 (age 54.237s)
  hex dump (first 32 bytes):
    01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 2f 30 0a 81 88 ff ff  ........./0.....
  backtrace:
    [<00000000e877f89f>] sock_alloc_inode+0x18/0x1c0
    [<0000000093d1dd51>] alloc_inode+0x63/0x1d0
    [<000000005673fec6>] new_inode_pseudo+0x14/0xe0
    [<00000000b5db6be8>] sock_alloc+0x3c/0x260
    [<00000000e7e3cbb2>] __sock_create+0x89/0x620
    [<0000000023e48593>] mptcp_subflow_create_socket+0xc0/0x5e0
    [<00000000419795e4>] __mptcp_socket_create+0x1ad/0x3f0
    [<00000000b2f942e8>] mptcp_stream_connect+0x281/0x4f0
    [<00000000c80cd5cc>] __sys_connect_file+0x14d/0x190
    [<00000000dc761f11>] __sys_connect+0x128/0x160
    [<000000008b14e764>] __x64_sys_connect+0x6f/0xb0
    [<000000007b4f93bd>] do_syscall_64+0xa1/0x530
    [<00000000d3e770b6>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

Fixes: 2303f994b3 ("mptcp: Associate MPTCP context with TCP socket")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-15 18:08:50 -07:00
Paolo Abeni 4b5af44129 mptcp: don't leak msk in token container
If a listening MPTCP socket has unaccepted sockets at close
time, the related msks are freed via mptcp_sock_destruct(),
which in turn does not invoke the proto->destroy() method
nor the mptcp_token_destroy() function.

Due to the above, the child msk socket is not removed from
the token container, leading to later UaF.

Address the issue explicitly removing the token even in the
above error path.

Fixes: 79c0949e9a ("mptcp: Add key generation and token tree")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-10 16:07:00 -07:00
Paolo Abeni 39884604b1 mptcp: fix NULL ptr dereference in MP_JOIN error path
When token lookup on MP_JOIN 3rd ack fails, the server
socket closes with a reset the incoming child. Such socket
has the 'is_mptcp' flag set, but no msk socket associated
- due to the failed lookup.

While crafting the reset packet mptcp_established_options_mp()
will try to dereference the child's master socket, causing
a NULL ptr dereference.

This change addresses the issue with explicit fallback to
TCP in such error path.

Fixes: 729cd6436f ("mptcp: cope better with MP_JOIN failure")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-30 21:54:03 -07:00
David S. Miller 13209a8f73 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
The MSCC bug fix in 'net' had to be slightly adjusted because the
register accesses are done slightly differently in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-24 13:47:27 -07:00
Todd Malsbary bd6972226f mptcp: use untruncated hash in ADD_ADDR HMAC
There is some ambiguity in the RFC as to whether the ADD_ADDR HMAC is
the rightmost 64 bits of the entire hash or of the leftmost 160 bits
of the hash.  The intention, as clarified with the author of the RFC,
is the entire hash.

This change returns the entire hash from
mptcp_crypto_hmac_sha (instead of only the first 160 bits), and moves
any truncation/selection operation on the hash to the caller.

Fixes: 12555a2d97 ("mptcp: use rightmost 64 bits in ADD_ADDR HMAC")
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Todd Malsbary <todd.malsbary@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-22 14:21:24 -07:00
Christoph Paasch a0c1d0eafd mptcp: Use 32-bit DATA_ACK when possible
RFC8684 allows to send 32-bit DATA_ACKs as long as the peer is not
sending 64-bit data-sequence numbers. The 64-bit DSN is only there for
extreme scenarios when a very high throughput subflow is combined with a
long-RTT subflow such that the high-throughput subflow wraps around the
32-bit sequence number space within an RTT of the high-RTT subflow.

It is thus a rare scenario and we should try to use the 32-bit DATA_ACK
instead as long as possible. It allows to reduce the TCP-option overhead
by 4 bytes, thus makes space for an additional SACK-block. It also makes
tcpdumps much easier to read when the DSN and DATA_ACK are both either
32 or 64-bit.

Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-16 13:51:10 -07:00
David S. Miller da07f52d3c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Move the bpf verifier trace check into the new switch statement in
HEAD.

Resolve the overlapping changes in hinic, where bug fixes overlap
the addition of VF support.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-15 13:48:59 -07:00
Paolo Abeni 729cd6436f mptcp: cope better with MP_JOIN failure
Currently, on MP_JOIN failure we reset the child
socket, but leave the request socket untouched.

tcp_check_req will deal with it according to the
'tcp_abort_on_overflow' sysctl value - by default the
req socket will stay alive.

The above leads to inconsistent behavior on MP JOIN
failure, and bad listener overflow accounting.

This patch addresses the issue leveraging the infrastructure
just introduced to ask the TCP stack to drop the req on
failure.

The child socket is not freed anymore by subflow_syn_recv_sock(),
instead it's moved to a dead state and will be disposed by the
next sock_put done by the TCP stack, so that listener overflow
accounting is not affected by MP JOIN failure.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-15 12:30:13 -07:00
Paolo Abeni 90bf45134d mptcp: add new sock flag to deal with join subflows
MP_JOIN subflows must not land into the accept queue.
Currently tcp_check_req() calls an mptcp specific helper
to detect such scenario.

Such helper leverages the subflow context to check for
MP_JOIN subflows. We need to deal also with MP JOIN
failures, even when the subflow context is not available
due allocation failure.

A possible solution would be changing the syn_recv_sock()
signature to allow returning a more descriptive action/
error code and deal with that in tcp_check_req().

Since the above need is MPTCP specific, this patch instead
uses a TCP request socket hole to add a MPTCP specific flag.
Such flag is used by the MPTCP syn_recv_sock() to tell
tcp_check_req() how to deal with the request socket.

This change is a no-op for !MPTCP build, and makes the
MPTCP code simpler. It allows also the next patch to deal
correctly with MP JOIN failure.

v1 -> v2:
 - be more conservative on drop_req initialization (Mat)

RFC -> v1:
 - move the drop_req bit inside tcp_request_sock (Eric)

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-15 12:30:13 -07:00
Paolo Abeni 7d14b0d2b9 mptcp: set correct vfs info for subflows
When a subflow is created via mptcp_subflow_create_socket(),
a new 'struct socket' is allocated, with a new i_ino value.

When inspecting TCP sockets via the procfs and or the diag
interface, the above ones are not related to the process owning
the MPTCP master socket, even if they are a logical part of it
('ss -p' shows an empty process field)

Additionally, subflows created by the path manager get
the uid/gid from the running workqueue.

Subflows are part of the owning MPTCP master socket, let's
adjust the vfs info to reflect this.

After this patch, 'ss' correctly displays subflows as belonging
to the msk socket creator.

Fixes: 2303f994b3 ("mptcp: Associate MPTCP context with TCP socket")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-07 18:16:05 -07:00
David S. Miller 3793faad7b Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Conflicts were all overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-06 22:10:13 -07:00
Paolo Abeni ac2b47fb92 mptcp: fix uninitialized value access
tcp_v{4,6}_syn_recv_sock() set 'own_req' only when returning
a not NULL 'child', let's check 'own_req' only if child is
available to avoid an - unharmful - UBSAN splat.

v1 -> v2:
 - reference the correct hash

Fixes: 4c8941de78 ("mptcp: avoid flipping mp_capable field in syn_recv_sock()")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 12:34:07 -07:00
Paolo Abeni cfde141ea3 mptcp: move option parsing into mptcp_incoming_options()
The mptcp_options_received structure carries several per
packet flags (mp_capable, mp_join, etc.). Such fields must
be cleared on each packet, even on dropped ones or packet
not carrying any MPTCP options, but the current mptcp
code clears them only on TCP option reset.

On several races/corner cases we end-up with stray bits in
incoming options, leading to WARN_ON splats. e.g.:

[  171.164906] Bad mapping: ssn=32714 map_seq=1 map_data_len=32713
[  171.165006] WARNING: CPU: 1 PID: 5026 at net/mptcp/subflow.c:533 warn_bad_map (linux-mptcp/net/mptcp/subflow.c:533 linux-mptcp/net/mptcp/subflow.c:531)
[  171.167632] Modules linked in: ip6_vti ip_vti ip_gre ipip sit tunnel4 ip_tunnel geneve ip6_udp_tunnel udp_tunnel macsec macvtap tap ipvlan macvlan 8021q garp mrp xfrm_interface veth netdevsim nlmon dummy team bonding vcan bridge stp llc ip6_gre gre ip6_tunnel tunnel6 tun binfmt_misc intel_rapl_msr intel_rapl_common rfkill kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel joydev virtio_balloon pcspkr i2c_piix4 sunrpc ip_tables xfs libcrc32c crc32c_intel serio_raw virtio_console ata_generic virtio_blk virtio_net net_failover failover ata_piix libata
[  171.199464] CPU: 1 PID: 5026 Comm: repro Not tainted 5.7.0-rc1.mptcp_f227fdf5d388+ #95
[  171.200886] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
[  171.202546] RIP: 0010:warn_bad_map (linux-mptcp/net/mptcp/subflow.c:533 linux-mptcp/net/mptcp/subflow.c:531)
[  171.206537] Code: c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 8b 55 3c 44 89 e6 48 c7 c7 20 51 13 95 e8 37 8b 22 fe <0f> 0b 48 83 c4 08 5b 5d 41 5c c3 89 4c 24 04 e8 db d6 94 fe 8b 4c
[  171.220473] RSP: 0018:ffffc90000150560 EFLAGS: 00010282
[  171.221639] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  171.223108] RDX: 0000000000000000 RSI: 0000000000000008 RDI: fffff5200002a09e
[  171.224388] RBP: ffff8880aa6e3c00 R08: 0000000000000001 R09: fffffbfff2ec9955
[  171.225706] R10: ffffffff9764caa7 R11: fffffbfff2ec9954 R12: 0000000000007fca
[  171.227211] R13: ffff8881066f4a7f R14: ffff8880aa6e3c00 R15: 0000000000000020
[  171.228460] FS:  00007f8623719740(0000) GS:ffff88810be00000(0000) knlGS:0000000000000000
[  171.230065] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  171.231303] CR2: 00007ffdab190a50 CR3: 00000001038ea006 CR4: 0000000000160ee0
[  171.232586] Call Trace:
[  171.233109]  <IRQ>
[  171.233531] get_mapping_status (linux-mptcp/net/mptcp/subflow.c:691)
[  171.234371] mptcp_subflow_data_available (linux-mptcp/net/mptcp/subflow.c:736 linux-mptcp/net/mptcp/subflow.c:832)
[  171.238181] subflow_state_change (linux-mptcp/net/mptcp/subflow.c:1085 (discriminator 1))
[  171.239066] tcp_fin (linux-mptcp/net/ipv4/tcp_input.c:4217)
[  171.240123] tcp_data_queue (linux-mptcp/./include/linux/compiler.h:199 linux-mptcp/net/ipv4/tcp_input.c:4822)
[  171.245083] tcp_rcv_established (linux-mptcp/./include/linux/skbuff.h:1785 linux-mptcp/./include/net/tcp.h:1774 linux-mptcp/./include/net/tcp.h:1847 linux-mptcp/net/ipv4/tcp_input.c:5238 linux-mptcp/net/ipv4/tcp_input.c:5730)
[  171.254089] tcp_v4_rcv (linux-mptcp/./include/linux/spinlock.h:393 linux-mptcp/net/ipv4/tcp_ipv4.c:2009)
[  171.258969] ip_protocol_deliver_rcu (linux-mptcp/net/ipv4/ip_input.c:204 (discriminator 1))
[  171.260214] ip_local_deliver_finish (linux-mptcp/./include/linux/rcupdate.h:651 linux-mptcp/net/ipv4/ip_input.c:232)
[  171.261389] ip_local_deliver (linux-mptcp/./include/linux/netfilter.h:307 linux-mptcp/./include/linux/netfilter.h:301 linux-mptcp/net/ipv4/ip_input.c:252)
[  171.265884] ip_rcv (linux-mptcp/./include/linux/netfilter.h:307 linux-mptcp/./include/linux/netfilter.h:301 linux-mptcp/net/ipv4/ip_input.c:539)
[  171.273666] process_backlog (linux-mptcp/./include/linux/rcupdate.h:651 linux-mptcp/net/core/dev.c:6135)
[  171.275328] net_rx_action (linux-mptcp/net/core/dev.c:6572 linux-mptcp/net/core/dev.c:6640)
[  171.280472] __do_softirq (linux-mptcp/./arch/x86/include/asm/jump_label.h:25 linux-mptcp/./include/linux/jump_label.h:200 linux-mptcp/./include/trace/events/irq.h:142 linux-mptcp/kernel/softirq.c:293)
[  171.281379] do_softirq_own_stack (linux-mptcp/arch/x86/entry/entry_64.S:1083)
[  171.282358]  </IRQ>

We could address the issue clearing explicitly the relevant fields
in several places - tcp_parse_option, tcp_fast_parse_options,
possibly others.

Instead we move the MPTCP option parsing into the already existing
mptcp ingress hook, so that we need to clear the fields in a single
place.

This allows us dropping an MPTCP hook from the TCP code and
removing the quite large mptcp_options_received from the tcp_sock
struct. On the flip side, the MPTCP sockets will traverse the
option space twice (in tcp_parse_option() and in
mptcp_incoming_options(). That looks acceptable: we already
do that for syn and 3rd ack packets, plain TCP socket will
benefit from it, and even MPTCP sockets will experience better
code locality, reducing the jumps between TCP and MPTCP code.

v1 -> v2:
 - rebased on current '-net' tree

Fixes: 648ef4b886 ("mptcp: Implement MPTCP receive path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 12:23:22 -07:00
Paolo Abeni 263e1201a2 mptcp: consolidate synack processing.
Currently the MPTCP code uses 2 hooks to process syn-ack
packets, mptcp_rcv_synsent() and the sk_rx_dst_set()
callback.

We can drop the first, moving the relevant code into the
latter, reducing the hooking into the TCP code. This is
also needed by the next patch.

v1 -> v2:
 - use local tcp sock ptr instead of casting the sk variable
   several times - DaveM

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 12:23:22 -07:00
Paolo Abeni 1200832c6e mptcp: fix race in msk status update
Currently subflow_finish_connect() changes unconditionally
any msk socket status other than TCP_ESTABLISHED.

If an unblocking connect() races with close(), we can end-up
triggering:

IPv4: Attempt to release TCP socket in state 1 00000000e32b8b7e

when the msk socket is disposed.

Be sure to enter the established status only from SYN_SENT.

Fixes: c3c123d16c ("net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-25 20:38:54 -07:00
Florian Westphal 071c8ed6e8 tcp: mptcp: use mptcp receive buffer space to select rcv window
In MPTCP, the receive window is shared across all subflows, because it
refers to the mptcp-level sequence space.

MPTCP receivers already place incoming packets on the mptcp socket
receive queue and will charge it to the mptcp socket rcvbuf until
userspace consumes the data.

Update __tcp_select_window to use the occupancy of the parent/mptcp
socket instead of the subflow socket in case the tcp socket is part
of a logical mptcp connection.

This commit doesn't change choice of initial window for passive or active
connections.
While it would be possible to change those as well, this adds complexity
(especially when handling MP_JOIN requests).  Furthermore, the MPTCP RFC
specifically says that a MPTCP sender 'MUST NOT use the RCV.WND field
of a TCP segment at the connection level if it does not also carry a DSS
option with a Data ACK field.'

SYN/SYNACK packets do not carry a DSS option with a Data ACK field.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-25 20:37:52 -07:00
Paolo Abeni fca5c82c08 mptcp: drop req socket remote_key* fields
We don't need them, as we can use the current ingress opt
data instead. Setting them in syn_recv_sock() may causes
inconsistent mptcp socket status, as per previous commit.

Fixes: cc7972ea19 ("mptcp: parse and emit MP_CAPABLE option according to v1 spec")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-20 12:59:33 -07:00
Paolo Abeni 4c8941de78 mptcp: avoid flipping mp_capable field in syn_recv_sock()
If multiple CPUs races on the same req_sock in syn_recv_sock(),
flipping such field can cause inconsistent child socket status.

When racing, the CPU losing the req ownership may still change
the mptcp request socket mp_capable flag while the CPU owning
the request is cloning the socket, leaving the child socket with
'is_mptcp' set but no 'mp_capable' flag.

Such socket will stay with 'conn' field cleared, heading to oops
in later mptcp callback.

Address the issue tracking the fallback status in a local variable.

Fixes: 58b0991962 ("mptcp: create msk early")
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-20 12:59:32 -07:00
Florian Westphal 9f5ca6a598 mptcp: fix 'Attempt to release TCP socket in state' warnings
We need to set sk_state to CLOSED, else we will get following:

IPv4: Attempt to release TCP socket in state 3 00000000b95f109e
IPv4: Attempt to release TCP socket in state 10 00000000b95f109e

First one is from inet_sock_destruct(), second one from
mptcp_sk_clone failure handling.  Setting sk_state to CLOSED isn't
enough, we also need to orphan sk so it has DEAD flag set.
Otherwise, a very similar warning is printed from inet_sock_destruct().

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-18 15:43:20 -07:00
Florian Westphal df1036da90 mptcp: fix splat when incoming connection is never accepted before exit/close
Following snippet (replicated from syzkaller reproducer) generates
warning: "IPv4: Attempt to release TCP socket in state 1".

int main(void) {
 struct sockaddr_in sin1 = { .sin_family = 2, .sin_port = 0x4e20,
                             .sin_addr.s_addr = 0x010000e0, };
 struct sockaddr_in sin2 = { .sin_family = 2,
	                     .sin_addr.s_addr = 0x0100007f, };
 struct sockaddr_in sin3 = { .sin_family = 2, .sin_port = 0x4e20,
	                     .sin_addr.s_addr = 0x0100007f, };
 int r0 = socket(0x2, 0x1, 0x106);
 int r1 = socket(0x2, 0x1, 0x106);

 bind(r1, (void *)&sin1, sizeof(sin1));
 connect(r1, (void *)&sin2, sizeof(sin2));
 listen(r1, 3);
 return connect(r0, (void *)&sin3, 0x4d);
}

Reason is that the newly generated mptcp socket is closed via the ulp
release of the tcp listener socket when its accept backlog gets purged.

To fix this, delay setting the ESTABLISHED state until after userspace
calls accept and via mptcp specific destructor.

Fixes: 58b0991962 ("mptcp: create msk early")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/9
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-18 15:43:20 -07:00
Florian Westphal 59832e2465 mptcp: subflow: check parent mptcp socket on subflow state change
This is needed at least until proper MPTCP-Level fin/reset
signalling gets added:

We wake parent when a subflow changes, but we should do this only
when all subflows have closed, not just one.

Schedule the mptcp worker and tell it to check eof state on all
subflows.

Only flag mptcp socket as closed and wake userspace processes blocking
in poll if all subflows have closed.

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-02 06:59:21 -07:00
Florian Westphal fc518953bc mptcp: add and use MIB counter infrastructure
Exported via same /proc file as the Linux TCP MIB counters, so "netstat -s"
or "nstat" will show them automatically.

The MPTCP MIB counters are allocated in a distinct pcpu area in order to
avoid bloating/wasting TCP pcpu memory.

Counters are allocated once the first MPTCP socket is created in a
network namespace and free'd on exit.

If no sockets have been allocated, all-zero mptcp counters are shown.

The MIB counter list is taken from the multipath-tcp.org kernel, but
only a few counters have been picked up so far.  The counter list can
be increased at any time later on.

v2 -> v3:
 - remove 'inline' in foo.c files (David S. Miller)

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29 22:14:49 -07:00
Davide Caratti 5147dfb508 mptcp: allow dumping subflow context to userspace
add ulp-specific diagnostic functions, so that subflow information can be
dumped to userspace programs like 'ss'.

v2 -> v3:
- uapi: use bit macros appropriate for userspace

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29 22:14:48 -07:00
Peter Krystad ec3edaa7ca mptcp: Add handling of outgoing MP_JOIN requests
Subflow creation may be initiated by the path manager when
the primary connection is fully established and a remote
address has been received via ADD_ADDR.

Create an in-kernel sock and use kernel_connect() to
initiate connection.

Passive sockets can't acquire the mptcp socket lock at
subflow creation time, so an additional list protected by
a new spinlock is used to track the MPJ subflows.

Such list is spliced into conn_list tail every time the msk
socket lock is acquired, so that it will not interfere
with data flow on the original connection.

Data flow and connection failover not addressed by this commit.

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29 22:14:48 -07:00
Peter Krystad f296234c98 mptcp: Add handling of incoming MP_JOIN requests
Process the MP_JOIN option in a SYN packet with the same flow
as MP_CAPABLE but when the third ACK is received add the
subflow to the MPTCP socket subflow list instead of adding it to
the TCP socket accept queue.

The subflow is added at the end of the subflow list so it will not
interfere with the existing subflows operation and no data is
expected to be transmitted on it.

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29 22:14:48 -07:00
Peter Krystad 1b1c7a0ef7 mptcp: Add path manager interface
Add enough of a path manager interface to allow sending of ADD_ADDR
when an incoming MPTCP connection is created. Capable of sending only
a single IPv4 ADD_ADDR option. The 'pm_data' element of the connection
sock will need to be expanded to handle multiple interfaces and IPv6.
Partial processing of the incoming ADD_ADDR is included so the path
manager notification of that event happens at the proper time, which
involves validating the incoming address information.

This is a skeleton interface definition for events generated by
MPTCP.

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29 22:14:48 -07:00
Davide Caratti c3c123d16c net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback
it's still possible for packetdrill to hang in mptcp_sendmsg(), when the
MPTCP socket falls back to regular TCP (e.g. after receiving unsupported
flags/version during the three-way handshake). Adjust MPTCP socket state
earlier, to ensure correct functionality of mptcp_sendmsg() even in case
of TCP fallback.

Fixes: 767d3ded5f ("net: mptcp: don't hang before sending 'MP capable with data'")
Fixes: 1954b86016 ("mptcp: Check connection state before attempting send")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-23 20:53:25 -07:00
Paolo Abeni 0be534f5c0 mptcp: rename fourth ack field
The name is misleading, it actually tracks the 'fully established'
status.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-19 20:19:34 -07:00
Paolo Abeni 7f20d5fc70 mptcp: move msk state update to subflow_syn_recv_sock()
After commit 58b0991962 ("mptcp: create msk early"), the
msk socket is already available at subflow_syn_recv_sock()
time. Let's move there the state update, to mirror more
closely the first subflow state.

The above will also help multiple subflow supports.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-17 22:52:24 -07:00
Paolo Abeni dc093db5cc mptcp: drop unneeded checks
After the previous patch subflow->conn is always != NULL and
is never changed. We can drop a bunch of now unneeded checks.

v1 -> v2:
 - rebased on top of commit 2398e3991b ("mptcp: always
   include dack if possible.")

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-15 00:19:03 -07:00
Paolo Abeni 58b0991962 mptcp: create msk early
This change moves the mptcp socket allocation from mptcp_accept() to
subflow_syn_recv_sock(), so that subflow->conn is now always set
for the non fallback scenario.

It allows cleaning up a bit mptcp_accept() reducing the additional
locking and will allow fourther cleanup in the next patch.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-15 00:19:03 -07:00
Florian Westphal 2e52213c79 mptcp: avoid work queue scheduling if possible
We can't lock_sock() the mptcp socket from the subflow data_ready callback,
it would result in ABBA deadlock with the subflow socket lock.

We can however grab the spinlock: if that succeeds and the mptcp socket
is not owned at the moment, we can process the new skbs right away
without deferring this to the work queue.

This avoids the schedule_work and hence the small delay until the
work item is processed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26 20:46:26 -08:00
Florian Westphal bfae9dae44 mptcp: remove mptcp_read_actor
Only used to discard stale data from the subflow, so move
it where needed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26 20:46:26 -08:00
Florian Westphal 101f6f851e mptcp: add and use mptcp_data_ready helper
allows us to schedule the work queue to drain the ssk receive queue in
a followup patch.

This is needed to avoid sending all-to-pessimistic mptcp-level
acknowledgements.  At this time, the ack_seq is what was last read by
userspace instead of the highest in-sequence number queued for reading.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26 20:46:26 -08:00
Geert Uytterhoeven 31484d56ca mptcp: Fix undefined mptcp_handle_ipv6_mapped for modular IPV6
If CONFIG_MPTCP=y, CONFIG_MPTCP_IPV6=n, and CONFIG_IPV6=m:

    ERROR: "mptcp_handle_ipv6_mapped" [net/ipv6/ipv6.ko] undefined!

This does not happen if CONFIG_MPTCP_IPV6=y, as CONFIG_MPTCP_IPV6
selects CONFIG_IPV6, and thus forces CONFIG_IPV6 builtin.

As exporting a symbol for an empty function would be a bit wasteful, fix
this by providing a dummy version of mptcp_handle_ipv6_mapped() for the
CONFIG_MPTCP_IPV6=n case.

Rename mptcp_handle_ipv6_mapped() to mptcpv6_handle_mapped(), to make it
clear this is a pure-IPV6 function, just like mptcpv6_init().

Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-30 10:55:54 +01:00
Florian Westphal ae2dd71649 mptcp: handle tcp fallback when using syn cookies
We can't deal with syncookie mode yet, the syncookie rx path will create
tcp reqsk, i.e. we get OOB access because we treat tcp reqsk as mptcp reqsk one:

TCP: SYN flooding on port 20002. Sending cookies.
BUG: KASAN: slab-out-of-bounds in subflow_syn_recv_sock+0x451/0x4d0 net/mptcp/subflow.c:191
Read of size 1 at addr ffff8881167bc148 by task syz-executor099/2120
 subflow_syn_recv_sock+0x451/0x4d0 net/mptcp/subflow.c:191
 tcp_get_cookie_sock+0xcf/0x520 net/ipv4/syncookies.c:209
 cookie_v6_check+0x15a5/0x1e90 net/ipv6/syncookies.c:252
 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1123 [inline]
 [..]

Bug can be reproduced via "sysctl net.ipv4.tcp_syncookies=2".

Note that MPTCP should work with syncookies (4th ack would carry needed
state), but it appears better to sort that out in -next so do tcp
fallback for now.

I removed the MPTCP ifdef for tcp_rsk "is_mptcp" member because
if (IS_ENABLED()) is easier to read than "#ifdef IS_ENABLED()/#endif" pair.

Cc: Eric Dumazet <edumazet@google.com>
Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Reported-by: Christoph Paasch <cpaasch@apple.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-29 17:45:20 +01:00
David S. Miller f6f7d8cf55 mptcp: Fix build with PROC_FS disabled.
net/mptcp/subflow.c: In function ‘mptcp_subflow_create_socket’:
net/mptcp/subflow.c:624:25: error: ‘struct netns_core’ has no member named ‘sock_inuse’

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-29 10:39:23 +01:00
Mat Martineau edc7e4898d mptcp: Fix code formatting
checkpatch.pl had a few complaints in the last set of MPTCP patches:

ERROR: code indent should use tabs where possible
+^I         subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);$

CHECK: Comparison to NULL could be written "!new_ctx"
+	if (new_ctx == NULL) {

ERROR: "foo * bar" should be "foo *bar"
+static const struct proto_ops * tcp_proto_ops(struct sock *sk)

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-25 08:14:39 +01:00
Christoph Paasch d22f4988ff mptcp: process MP_CAPABLE data option
This patch implements the handling of MP_CAPABLE + data option, as per
RFC 6824 bis / RFC 8684: MPTCP v1.

On the server side we can receive the remote key after that the connection
is established. We need to explicitly track the 'missing remote key'
status and avoid emitting a mptcp ack until we get such info.

When a late/retransmitted/OoO pkt carrying MP_CAPABLE[+data] option
is received, we have to propagate the mptcp seq number info to
the msk socket. To avoid ABBA locking issue, explicitly check for
that in recvmsg(), where we own msk and subflow sock locks.

The above also means that an established mp_capable subflow - still
waiting for the remote key - can be 'downgraded' to plain TCP.

Such change could potentially block a reader waiting for new data
forever - as they hook to msk, while later wake-up after the downgrade
will be on subflow only.

The above issue is not handled here, we likely have to get rid of
msk->fallback to handle that cleanly.

Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:08 +01:00
Christoph Paasch cc7972ea19 mptcp: parse and emit MP_CAPABLE option according to v1 spec
This implements MP_CAPABLE options parsing and writing according
to RFC 6824 bis / RFC 8684: MPTCP v1.

Local key is sent on syn/ack, and both keys are sent on 3rd ack.
MP_CAPABLE messages len are updated accordingly. We need the skbuff to
correctly emit the above, so we push the skbuff struct as an argument
all the way from tcp code to the relevant mptcp callbacks.

When processing incoming MP_CAPABLE + data, build a full blown DSS-like
map info, to simplify later processing.  On child socket creation, we
need to record the remote key, if available.

Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:08 +01:00
Florian Westphal 1891c4a076 mptcp: add subflow write space signalling and mptcp_poll
Add new SEND_SPACE flag to indicate that a subflow has enough space to
accept more data for transmission.

It gets cleared at the end of mptcp_sendmsg() in case ssk has run
below the free watermark.

It is (re-set) from the wspace callback.

This allows us to use msk->flags to determine the poll mask.

Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:08 +01:00
Mat Martineau 648ef4b886 mptcp: Implement MPTCP receive path
Parses incoming DSS options and populates outgoing MPTCP ACK
fields. MPTCP fields are parsed from the TCP option header and placed in
an skb extension, allowing the upper MPTCP layer to access MPTCP
options after the skb has gone through the TCP stack.

The subflow implements its own data_ready() ops, which ensures that the
pending data is in sequence - according to MPTCP seq number - dropping
out-of-seq skbs. The DATA_READY bit flag is set if this is the case.
This allows the MPTCP socket layer to determine if more data is
available without having to consult the individual subflows.

It additionally validates the current mapping and propagates EoF events
to the connection socket.

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:07 +01:00
Peter Krystad 79c0949e9a mptcp: Add key generation and token tree
Generate the local keys, IDSN, and token when creating a new socket.
Introduce the token tree to track all tokens in use using a radix tree
with the MPTCP token itself as the index.

Override the rebuild_header callback in inet_connection_sock_af_ops for
creating the local key on a new outgoing connection.

Override the init_req callback of tcp_request_sock_ops for creating the
local key on a new incoming connection.

Will be used to obtain the MPTCP parent socket to handle incoming joins.

Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:07 +01:00
Peter Krystad cec37a6e41 mptcp: Handle MP_CAPABLE options for outgoing connections
Add hooks to tcp_output.c to add MP_CAPABLE to an outgoing SYN request,
to capture the MP_CAPABLE in the received SYN-ACK, to add MP_CAPABLE to
the final ACK of the three-way handshake.

Use the .sk_rx_dst_set() handler in the subflow proto to capture when the
responding SYN-ACK is received and notify the MPTCP connection layer.

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:07 +01:00
Peter Krystad 2303f994b3 mptcp: Associate MPTCP context with TCP socket
Use ULP to associate a subflow_context structure with each TCP subflow
socket. Creating these sockets requires new bind and connect functions
to make sure ULP is set up immediately when the subflow sockets are
created.

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24 13:44:07 +01:00