Commit Graph

320 Commits

Author SHA1 Message Date
Paolo Abeni 37d9305caa mptcp: prevent MPC handshake on port-based signal endpoints
commit 3d041393ea8c815f773020fb4a995331a69c0139 upstream.

Syzkaller reported a lockdep splat:

  ============================================
  WARNING: possible recursive locking detected
  6.11.0-rc6-syzkaller-00019-g67784a74e258 #0 Not tainted
  --------------------------------------------
  syz-executor364/5113 is trying to acquire lock:
  ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
  ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  but task is already holding lock:
  ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
  ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(k-slock-AF_INET);
    lock(k-slock-AF_INET);

   *** DEADLOCK ***

   May be due to missing lock nesting notation

  7 locks held by syz-executor364/5113:
   #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline]
   #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x153/0x1b10 net/mptcp/protocol.c:1806
   #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline]
   #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg_fastopen+0x11f/0x530 net/mptcp/protocol.c:1727
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x5f/0x1b80 net/ipv4/ip_output.c:470
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1390 net/ipv4/ip_output.c:228
   #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
   #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x33b/0x15b0 net/core/dev.c:6104
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x230/0x5f0 net/ipv4/ip_input.c:232
   #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
   #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  stack backtrace:
  CPU: 0 UID: 0 PID: 5113 Comm: syz-executor364 Not tainted 6.11.0-rc6-syzkaller-00019-g67784a74e258 #0
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
  Call Trace:
   <IRQ>
   __dump_stack lib/dump_stack.c:93 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
   check_deadlock kernel/locking/lockdep.c:3061 [inline]
   validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3855
   __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
   lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
   __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
   _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
   spin_lock include/linux/spinlock.h:351 [inline]
   sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328
   mptcp_sk_clone_init+0x32/0x13c0 net/mptcp/protocol.c:3279
   subflow_syn_recv_sock+0x931/0x1920 net/mptcp/subflow.c:874
   tcp_check_req+0xfe4/0x1a20 net/ipv4/tcp_minisocks.c:853
   tcp_v4_rcv+0x1c3e/0x37f0 net/ipv4/tcp_ipv4.c:2267
   ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
   ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
   NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
   NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
   __netif_receive_skb_one_core net/core/dev.c:5661 [inline]
   __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775
   process_backlog+0x662/0x15b0 net/core/dev.c:6108
   __napi_poll+0xcb/0x490 net/core/dev.c:6772
   napi_poll net/core/dev.c:6841 [inline]
   net_rx_action+0x89b/0x1240 net/core/dev.c:6963
   handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
   do_softirq+0x11b/0x1e0 kernel/softirq.c:455
   </IRQ>
   <TASK>
   __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
   local_bh_enable include/linux/bottom_half.h:33 [inline]
   rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline]
   __dev_queue_xmit+0x1763/0x3e90 net/core/dev.c:4450
   dev_queue_xmit include/linux/netdevice.h:3105 [inline]
   neigh_hh_output include/net/neighbour.h:526 [inline]
   neigh_output include/net/neighbour.h:540 [inline]
   ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:235
   ip_local_out net/ipv4/ip_output.c:129 [inline]
   __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:535
   __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466
   tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6542 [inline]
   tcp_rcv_state_process+0x2c32/0x4570 net/ipv4/tcp_input.c:6729
   tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1934
   sk_backlog_rcv include/net/sock.h:1111 [inline]
   __release_sock+0x214/0x350 net/core/sock.c:3004
   release_sock+0x61/0x1f0 net/core/sock.c:3558
   mptcp_sendmsg_fastopen+0x1ad/0x530 net/mptcp/protocol.c:1733
   mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1812
   sock_sendmsg_nosec net/socket.c:730 [inline]
   __sock_sendmsg+0x1a6/0x270 net/socket.c:745
   ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
   ___sys_sendmsg net/socket.c:2651 [inline]
   __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737
   __do_sys_sendmmsg net/socket.c:2766 [inline]
   __se_sys_sendmmsg net/socket.c:2763 [inline]
   __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  RIP: 0033:0x7f04fb13a6b9
  Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 00 00 90 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 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
  RSP: 002b:00007ffd651f42d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
  RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f04fb13a6b9
  RDX: 0000000000000001 RSI: 0000000020000d00 RDI: 0000000000000004
  RBP: 00007ffd651f4310 R08: 0000000000000001 R09: 0000000000000001
  R10: 0000000020000080 R11: 0000000000000246 R12: 00000000000f4240
  R13: 00007f04fb187449 R14: 00007ffd651f42f4 R15: 00007ffd651f4300
   </TASK>

As noted by Cong Wang, the splat is false positive, but the code
path leading to the report is an unexpected one: a client is
attempting an MPC handshake towards the in-kernel listener created
by the in-kernel PM for a port based signal endpoint.

Such connection will be never accepted; many of them can make the
listener queue full and preventing the creation of MPJ subflow via
such listener - its intended role.

Explicitly detect this scenario at initial-syn time and drop the
incoming MPC request.

Fixes: 1729cf186d ("mptcp: create the listening socket for new port")
Cc: stable@vger.kernel.org
Reported-by: syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f4aacdfef2c6a6529c3e
Cc: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241014-net-mptcp-mpc-port-endp-v2-1-7faea8e6b6ae@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in mib.[ch], because commit 6982826fe5e5 ("mptcp: fallback
  to TCP after SYN+MPC drops"), and commit 27069e7cb3d1 ("mptcp: disable
  active MPTCP in case of blackhole") are linked to new features, not
  available in this version. Resolving the conflicts is easy, simply
  adding the new lines declaring the new "endpoint attempt" MIB entry. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-22 15:46:25 +02:00
Matthieu Baerts (NGI0) 3d2e1b8255 mptcp: pr_debug: add missing \n at the end
commit cb41b195e634d3f1ecfcd845314e64fd4bb3c7aa upstream.

pr_debug() have been added in various places in MPTCP code to help
developers to debug some situations. With the dynamic debug feature, it
is easy to enable all or some of them, and asks users to reproduce
issues with extra debug.

Many of these pr_debug() don't end with a new line, while no 'pr_cont()'
are used in MPTCP code. So the goal was not to display multiple debug
messages on one line: they were then not missing the '\n' on purpose.
Not having the new line at the end causes these messages to be printed
with a delay, when something else needs to be printed. This issue is not
visible when many messages need to be printed, but it is annoying and
confusing when only specific messages are expected, e.g.

  # echo "func mptcp_pm_add_addr_echoed +fmp" \
        > /sys/kernel/debug/dynamic_debug/control
  # ./mptcp_join.sh "signal address"; \
        echo "$(awk '{print $1}' /proc/uptime) - end"; \
        sleep 5s; \
        echo "$(awk '{print $1}' /proc/uptime) - restart"; \
        ./mptcp_join.sh "signal address"
  013 signal address
      (...)
  10.75 - end
  15.76 - restart
  013 signal address
  [  10.367935] mptcp:mptcp_pm_add_addr_echoed: MPTCP: msk=(...)
      (...)

  => a delay of 5 seconds: printed with a 10.36 ts, but after 'restart'
     which was printed at the 15.76 ts.

The 'Fixes' tag here below points to the first pr_debug() used without
'\n' in net/mptcp. This patch could be split in many small ones, with
different Fixes tag, but it doesn't seem worth it, because it is easy to
re-generate this patch with this simple 'sed' command:

  git grep -l pr_debug -- net/mptcp |
    xargs sed -i "s/\(pr_debug(\".*[^n]\)\(\"[,)]\)/\1\\\n\2/g"

So in case of conflicts, simply drop the modifications, and launch this
command.

Fixes: f870fa0b57 ("mptcp: Add MPTCP socket stubs")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240826-net-mptcp-close-extra-sf-fin-v1-4-905199fe1172@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ As mentioned above, conflicts were expected, and resolved by using the
  'sed' command which is visible above. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-08 07:54:35 +02:00
Matthieu Baerts (NGI0) a088190f3f mptcp: avoid duplicated SUB_CLOSED events
commit d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 upstream.

The initial subflow might have already been closed, but still in the
connection list. When the worker is instructed to close the subflows
that have been marked as closed, it might then try to close the initial
subflow again.

 A consequence of that is that the SUB_CLOSED event can be seen twice:

  # ip mptcp endpoint
  1.1.1.1 id 1 subflow dev eth0
  2.2.2.2 id 2 subflow dev eth1

  # ip mptcp monitor &
  [         CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [     ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [  SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9

  # ip mptcp endpoint delete id 1
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9

The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the
second one from __mptcp_close_subflow().

To avoid doing the post-closed processing twice, the subflow is now
marked as closed the first time.

Note that it is not enough to check if we are dealing with the first
subflow and check its sk_state: the subflow might have been reset or
closed before calling mptcp_close_ssk().

Fixes: b911c97c7d ("mptcp: add netlink event support")
Cc: stable@vger.kernel.org
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ Conflict in protocol.h due to commit f1f26512a9bf ("mptcp: use plain
  bool instead of custom binary enum") and more that are not in this
  version, because they modify the context and the size of __unused. The
  conflict is easy to resolve, by not modifying data_avail type. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-08 07:54:35 +02:00
Geliang Tang 0229074a51 mptcp: make pm_remove_addrs_and_subflows static
[ Upstream commit e38b117d7f3b4a5d810f6d0069ad0f643e503796 ]

mptcp_pm_remove_addrs_and_subflows() is only used in pm_netlink.c, it's
no longer used in pm_userspace.c any more since the commit 8b1c94da1e
("mptcp: only send RM_ADDR in nl_cmd_remove"). So this patch changes it
to a static function.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 87b5896f3f78 ("mptcp: pm: fix RM_ADDR ID for the initial subflow")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-08 07:54:32 +02:00
Matthieu Baerts (NGI0) dc14d542e6 mptcp: pm: ADD_ADDR 0 is not a new address
commit 57f86203b41c98b322119dfdbb1ec54ce5e3369b upstream.

The ADD_ADDR 0 with the address from the initial subflow should not be
considered as a new address: this is not something new. If the host
receives it, it simply means that the address is available again.

When receiving an ADD_ADDR for the ID 0, the PM already doesn't consider
it as new by not incrementing the 'add_addr_accepted' counter. But the
'accept_addr' might not be set if the limit has already been reached:
this can be bypassed in this case. But before, it is important to check
that this ADD_ADDR for the ID 0 is for the same address as the initial
subflow. If not, it is not something that should happen, and the
ADD_ADDR can be ignored.

Note that if an ADD_ADDR is received while there is already a subflow
opened using the same address, this ADD_ADDR is ignored as well. It
means that if multiple ADD_ADDR for ID 0 are received, there will not be
any duplicated subflows created by the client.

Fixes: d0876b2284 ("mptcp: add the incoming RM_ADDR support")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-04 13:28:21 +02:00
Matthieu Baerts (NGI0) 01db518468 mptcp: pm: remove mptcp_pm_remove_subflow()
commit f448451aa62d54be16acb0034223c17e0d12bc69 upstream.

This helper is confusing. It is in pm.c, but it is specific to the
in-kernel PM and it cannot be used by the userspace one. Also, it simply
calls one in-kernel specific function with the PM lock, while the
similar mptcp_pm_remove_addr() helper requires the PM lock.

What's left is the pr_debug(), which is not that useful, because a
similar one is present in the only function called by this helper:

  mptcp_pm_nl_rm_subflow_received()

After these modifications, this helper can be marked as 'static', and
the lock can be taken only once in mptcp_pm_flush_addrs_and_subflows().

Note that it is not a bug fix, but it will help backporting the
following commits.

Fixes: 0ee4261a36 ("mptcp: implement mptcp_pm_remove_subflow")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-7-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-29 17:33:55 +02:00
Matthieu Baerts (NGI0) fff9b9208c mptcp: pm: fix backup support in signal endpoints
commit 6834097fc38c5416701c793da94558cea49c0a1f upstream.

There was a support for signal endpoints, but only when the endpoint's
flag was changed during a connection. If an endpoint with the signal and
backup was already present, the MP_JOIN reply was not containing the
backup flag as expected.

That's confusing to have this inconsistent behaviour. On the other hand,
the infrastructure to set the backup flag in the SYN + ACK + MP_JOIN was
already there, it was just never set before. Now when requesting the
local ID from the path-manager, the backup status is also requested.

Note that when the userspace PM is used, the backup flag can be set if
the local address was already used before with a backup flag, e.g. if
the address was announced with the 'backup' flag, or a subflow was
created with the 'backup' flag.

Fixes: 4596a2c1b7 ("mptcp: allow creating non-backup subflows")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/507
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ Conflicts in pm_userspace.c because the context has changed in commit
  1e07938e29c5 ("net: mptcp: rename netlink handlers to
  mptcp_pm_nl_<blah>_{doit,dumpit}") which is not in this version. This
  commit is unrelated to this modification.
  Conflicts in protocol.h because the context has changed in commit
  9ae7846c4b6b ("mptcp: dump addrs in userspace pm list") which is not
  in this version. This commit is unrelated to this modification. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-14 13:59:01 +02:00
Matthieu Baerts (NGI0) 8ed3e34c76 mptcp: distinguish rcv vs sent backup flag in requests
commit efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 upstream.

When sending an MP_JOIN + SYN + ACK, it is possible to mark the subflow
as 'backup' by setting the flag with the same name. Before this patch,
the backup was set if the other peer set it in its MP_JOIN + SYN
request.

It is not correct: the backup flag should be set in the MPJ+SYN+ACK only
if the host asks for it, and not mirroring what was done by the other
peer. It is then required to have a dedicated bit for each direction,
similar to what is done in the subflow context.

Fixes: f296234c98 ("mptcp: Add handling of incoming MP_JOIN requests")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-11 12:47:26 +02:00
Paolo Abeni 124a4885b5 mptcp: give rcvlowat some love
[ Upstream commit 5684ab1a0effbfeb706f47d85785f653005b97b1 ]

The MPTCP protocol allow setting sk_rcvlowat, but the value there
is currently ignored.

Additionally, the default subflows sk_rcvlowat basically disables per
subflow delayed ack: the MPTCP protocol move the incoming data from the
subflows into the msk socket as soon as the TCP stacks invokes the subflow
data_ready callback. Later, when __tcp_ack_snd_check() takes action,
the subflow-level copied_seq matches rcv_nxt, and that mandate for an
immediate ack.

Let the mptcp receive path be aware of such threshold, explicitly tracking
the amount of data available to be ready and checking vs sk_rcvlowat in
mptcp_poll() and before waking-up readers.

Additionally implement the set_rcvlowat() callback, to properly handle
the rcvbuf auto-tuning on sk_rcvlowat changes.

Finally to properly handle delayed ack, force the subflow level threshold
to 0 and instead explicitly ask for an immediate ack when the msk level th
is not reached.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-5-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 05f76b2d634e ("tcp: Adjust clamping window for applications specifying SO_RCVBUF")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-11 12:47:19 +02:00
Matthieu Baerts (NGI0) 184873af87 mptcp: fix full TCP keep-alive support
commit bd11dc4fb969ec148e50cd87f88a78246dbc4d0b upstream.

SO_KEEPALIVE support has been added a while ago, as part of a series
"adding SOL_SOCKET" support. To have a full control of this keep-alive
feature, it is important to also support TCP_KEEP* socket options at the
SOL_TCP level.

Supporting them on the setsockopt() part is easy, it is just a matter of
remembering each value in the MPTCP sock structure, and calling
tcp_sock_set_keep*() helpers on each subflow. If the value is not
modified (0), calling these helpers will not do anything. For the
getsockopt() part, the corresponding value from the MPTCP sock structure
or the default one is simply returned. All of this is very similar to
other TCP_* socket options supported by MPTCP.

It looks important for kernels supporting SO_KEEPALIVE, to also support
TCP_KEEP* options as well: some apps seem to (wrongly) consider that if
the former is supported, the latter ones will be supported as well. But
also, not having this simple and isolated change is preventing MPTCP
support in some apps, and libraries like GoLang [1]. This is why this
patch is seen as a fix.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/383
Fixes: 1b3e7ede13 ("mptcp: setsockopt: handle SO_KEEPALIVE and SO_PRIORITY")
Link: https://github.com/golang/go/issues/56539 [1]
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20240514011335.176158-3-martineau@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ conflicts in the same context, because commit 29b5e5ef8739 ("mptcp:
  implement TCP_NOTSENT_LOWAT support") is not in this version ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:31 +02:00
Paolo Abeni b609ecda2d mptcp: fix potential wake-up event loss
commit b111d8fbd2cbc63e05f3adfbbe0d4df655dfcc5b upstream.

After the blamed commit below, the send buffer auto-tuning can
happen after that the mptcp_propagate_sndbuf() completes - via
the delegated action infrastructure.

We must check for write space even after such change or we risk
missing the wake-up event.

Fixes: 8005184fd1ca ("mptcp: refactor sndbuf auto-tuning")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-6-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-06 14:48:42 +00:00
Paolo Abeni ba2cf92250 mptcp: fix data races on local_id
commit a7cfe776637004a4c938fde78be4bd608c32c3ef upstream.

The local address id is accessed lockless by the NL PM, add
all the required ONCE annotation. There is a caveat: the local
id can be initialized late in the subflow life-cycle, and its
validity is controlled by the local_id_valid flag.

Remove such flag and encode the validity in the local_id field
itself with negative value before initialization. That allows
accessing the field consistently with a single read operation.

Fixes: 0ee4261a36 ("mptcp: implement mptcp_pm_remove_subflow")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-01 13:35:03 +01:00
Paolo Abeni b45df837fe mptcp: corner case locking for rx path fields initialization
[ Upstream commit e4a0fa47e816e186f6b4c0055d07eeec42d11871 ]

Most MPTCP-level related fields are under the mptcp data lock
protection, but are written one-off without such lock at MPC
complete time, both for the client and the server

Leverage the mptcp_propagate_state() infrastructure to move such
initialization under the proper lock client-wise.

The server side critical init steps are done by
mptcp_subflow_fully_established(): ensure the caller properly held the
relevant lock, and avoid acquiring the same lock in the nested scopes.

There are no real potential races, as write access to such fields
is implicitly serialized by the MPTCP state machine; the primary
goal is consistency.

Fixes: d22f4988ff ("mptcp: process MP_CAPABLE data option")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:34:57 +01:00
Geliang Tang 5655754731 mptcp: add CurrEstab MIB counter support
[ Upstream commit d9cd27b8cd191133e287e5de107f971136abe8a2 ]

Add a new MIB counter named MPTCP_MIB_CURRESTAB to count current
established MPTCP connections, similar to TCP_MIB_CURRESTAB. This is
useful to quickly list the number of MPTCP connections without having to
iterate over all of them.

This patch adds a new helper function mptcp_set_state(): if the state
switches from or to ESTABLISHED state, this newly added counter is
incremented. This helper is going to be used in the following patch.

Similar to MPTCP_INC_STATS(), a new helper called MPTCP_DEC_STATS() is
also needed to decrement a MIB counter.

Signed-off-by: Geliang Tang <geliang.tang@linux.dev>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: e4a0fa47e816 ("mptcp: corner case locking for rx path fields initialization")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:34:57 +01:00
Paolo Abeni 4bfe217e07 mptcp: really cope with fastopen race
commit 337cebbd850f94147cee05252778f8f78b8c337f upstream.

Fastopen and PM-trigger subflow shutdown can race, as reported by
syzkaller.

In my first attempt to close such race, I missed the fact that
the subflow status can change again before the subflow_state_change
callback is invoked.

Address the issue additionally copying with all the states directly
reachable from TCP_FIN_WAIT1.

Fixes: 1e777f39b4 ("mptcp: add MSG_FASTOPEN sendmsg flag support")
Fixes: 4fd19a307016 ("mptcp: fix inconsistent state on fastopen race")
Cc: stable@vger.kernel.org
Reported-by: syzbot+c53d4d3ddb327e80bc51@syzkaller.appspotmail.com
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/458
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:25:01 +01:00
Paolo Abeni a2d743747e mptcp: fix rcv space initialization
commit 013e3179dbd2bc756ce1dd90354abac62f65b739 upstream.

mptcp_rcv_space_init() is supposed to happen under the msk socket
lock, but active msk socket does that without such protection.

Leverage the existing mptcp_propagate_state() helper to that extent.
We need to ensure mptcp_rcv_space_init will happen before
mptcp_rcv_space_adjust(), and the release_cb does not assure that:
explicitly check for such condition.

While at it, move the wnd_end initialization out of mptcp_rcv_space_init(),
it never belonged there.

Note that the race does not produce ill effect in practice, but
change allows cleaning-up and defying better the locking model.

Fixes: a6b118febb ("mptcp: add receive buffer auto-tuning")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:25:00 +01:00
Paolo Abeni 877a72e3b6 mptcp: drop the push_pending field
commit bdd70eb68913c960acb895b00a8c62eb64715b1f upstream.

Such field is there to avoid acquiring the data lock in a few spots,
but it adds complexity to the already non trivial locking schema.

All the relevant call sites (mptcp-level re-injection, set socket
options), are slow-path, drop such field in favor of 'cb_flags', adding
the relevant locking.

This patch could be seen as an improvement, instead of a fix. But it
simplifies the next patch. The 'Fixes' tag has been added to help having
this series backported to stable.

Fixes: e9d09baca6 ("mptcp: avoid atomic bit manipulation when possible")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:25:00 +01:00
Paolo Abeni cf742d0955 mptcp: fix inconsistent state on fastopen race
[ Upstream commit 4fd19a30701659af5839b7bd19d1f05f05933ebe ]

The netlink PM can race with fastopen self-connect attempts, shutting
down the first subflow via:

MPTCP_PM_CMD_DEL_ADDR -> mptcp_nl_remove_id_zero_address ->
  mptcp_pm_nl_rm_subflow_received -> mptcp_close_ssk

and transitioning such subflow to FIN_WAIT1 status before the syn-ack
packet is processed. The MPTCP code does not react to such state change,
leaving the connection in not-fallback status and the subflow handshake
uncompleted, triggering the following splat:

  WARNING: CPU: 0 PID: 10630 at net/mptcp/subflow.c:1405 subflow_data_ready+0x39f/0x690 net/mptcp/subflow.c:1405
  Modules linked in:
  CPU: 0 PID: 10630 Comm: kworker/u4:11 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
  Workqueue: bat_events batadv_nc_worker
  RIP: 0010:subflow_data_ready+0x39f/0x690 net/mptcp/subflow.c:1405
  Code: 18 89 ee e8 e3 d2 21 f7 40 84 ed 75 1f e8 a9 d7 21 f7 44 89 fe bf 07 00 00 00 e8 0c d3 21 f7 41 83 ff 07 74 07 e8 91 d7 21 f7 <0f> 0b e8 8a d7 21 f7 48 89 df e8 d2 b2 ff ff 31 ff 89 c5 89 c6 e8
  RSP: 0018:ffffc90000007448 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffff888031efc700 RCX: ffffffff8a65baf4
  RDX: ffff888043222140 RSI: ffffffff8a65baff RDI: 0000000000000005
  RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000007
  R10: 000000000000000b R11: 0000000000000000 R12: 1ffff92000000e89
  R13: ffff88807a534d80 R14: ffff888021c11a00 R15: 000000000000000b
  FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fa19a0ffc81 CR3: 000000007a2db000 CR4: 00000000003506f0
  DR0: 000000000000d8dd DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Call Trace:
   <IRQ>
   tcp_data_ready+0x14c/0x5b0 net/ipv4/tcp_input.c:5128
   tcp_data_queue+0x19c3/0x5190 net/ipv4/tcp_input.c:5208
   tcp_rcv_state_process+0x11ef/0x4e10 net/ipv4/tcp_input.c:6844
   tcp_v4_do_rcv+0x369/0xa10 net/ipv4/tcp_ipv4.c:1929
   tcp_v4_rcv+0x3888/0x3b30 net/ipv4/tcp_ipv4.c:2329
   ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205
   ip_local_deliver_finish+0x2e4/0x510 net/ipv4/ip_input.c:233
   NF_HOOK include/linux/netfilter.h:314 [inline]
   NF_HOOK include/linux/netfilter.h:308 [inline]
   ip_local_deliver+0x1b6/0x550 net/ipv4/ip_input.c:254
   dst_input include/net/dst.h:461 [inline]
   ip_rcv_finish+0x1c4/0x2e0 net/ipv4/ip_input.c:449
   NF_HOOK include/linux/netfilter.h:314 [inline]
   NF_HOOK include/linux/netfilter.h:308 [inline]
   ip_rcv+0xce/0x440 net/ipv4/ip_input.c:569
   __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5527
   __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5641
   process_backlog+0x101/0x6b0 net/core/dev.c:5969
   __napi_poll.constprop.0+0xb4/0x540 net/core/dev.c:6531
   napi_poll net/core/dev.c:6600 [inline]
   net_rx_action+0x956/0xe90 net/core/dev.c:6733
   __do_softirq+0x21a/0x968 kernel/softirq.c:553
   do_softirq kernel/softirq.c:454 [inline]
   do_softirq+0xaa/0xe0 kernel/softirq.c:441
   </IRQ>
   <TASK>
   __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:381
   spin_unlock_bh include/linux/spinlock.h:396 [inline]
   batadv_nc_purge_paths+0x1ce/0x3c0 net/batman-adv/network-coding.c:471
   batadv_nc_worker+0x9b1/0x10e0 net/batman-adv/network-coding.c:722
   process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
   process_scheduled_works kernel/workqueue.c:2703 [inline]
   worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
   kthread+0x33c/0x440 kernel/kthread.c:388
   ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
   </TASK>

To address the issue, catch the racing subflow state change and
use it to cause the MPTCP fallback. Such fallback is also used to
cause the first subflow state propagation to the msk socket via
mptcp_set_connected(). After this change, the first subflow can
additionally propagate the TCP_FIN_WAIT1 state, so rename the
helper accordingly.

Finally, if the state propagation is delayed to the msk release
callback, the first subflow can change to a different state in between.
Cache the relevant target state in a new msk-level field and use
such value to update the msk state at release time.

Fixes: 1e777f39b4 ("mptcp: add MSG_FASTOPEN sendmsg flag support")
Cc: stable@vger.kernel.org
Reported-by: <syzbot+c53d4d3ddb327e80bc51@syzkaller.appspotmail.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/458
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-05 15:19:42 +01:00
Paolo Abeni 34c7757aa5 mptcp: refactor sndbuf auto-tuning
[ Upstream commit 8005184fd1ca6aeb3fea36f4eb9463fc1b90c114 ]

The MPTCP protocol account for the data enqueued on all the subflows
to the main socket send buffer, while the send buffer auto-tuning
algorithm set the main socket send buffer size as the max size among
the subflows.

That causes bad performances when at least one subflow is sndbuf
limited, e.g. due to very high latency, as the MPTCP scheduler can't
even fill such buffer.

Change the send-buffer auto-tuning algorithm to compute the main socket
send buffer size as the sum of all the subflows buffer size.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-9-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 4fd19a307016 ("mptcp: fix inconsistent state on fastopen race")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-05 15:19:41 +01:00
Paolo Abeni a5efdbcece mptcp: fix delegated action races
The delegated action infrastructure is prone to the following
race: different CPUs can try to schedule different delegated
actions on the same subflow at the same time.

Each of them will check different bits via mptcp_subflow_delegate(),
and will try to schedule the action on the related per-cpu napi
instance.

Depending on the timing, both can observe an empty delegated list
node, causing the same entry to be added simultaneously on two different
lists.

The root cause is that the delegated actions infra does not provide
a single synchronization point. Address the issue reserving an additional
bit to mark the subflow as scheduled for delegation. Acquiring such bit
guarantee the caller to own the delegated list node, and being able to
safely schedule the subflow.

Clear such bit only when the subflow scheduling is completed, ensuring
proper barrier in place.

Additionally swap the meaning of the delegated_action bitmask, to allow
the usage of the existing helper to set multiple bit at once.

Fixes: bcd9773431 ("mptcp: use delegate action to schedule 3rd ack retrans")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231004-send-net-20231004-v1-1-28de4ac663ae@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-10-05 09:34:31 -07:00
Paolo Abeni 27e5ccc2d5 mptcp: fix dangling connection hang-up
According to RFC 8684 section 3.3:

  A connection is not closed unless [...] or an implementation-specific
  connection-level send timeout.

Currently the MPTCP protocol does not implement such timeout, and
connection timing-out at the TCP-level never move to close state.

Introduces a catch-up condition at subflow close time to move the
MPTCP socket to close, too.

That additionally allows removing similar existing inside the worker.

Finally, allow some additional timeout for plain ESTABLISHED mptcp
sockets, as the protocol allows creating new subflows even at that
point and making the connection functional again.

This issue is actually present since the beginning, but it is basically
impossible to solve without a long chain of functional pre-requisites
topped by commit bbd49d114d ("mptcp: consolidate transition to
TCP_CLOSE in mptcp_do_fastclose()"). When backporting this current
patch, please also backport this other commit as well.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/430
Fixes: e16163b6e2 ("mptcp: refactor shutdown and close")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-09-18 12:47:56 +01:00
Paolo Abeni f6909dc1c1 mptcp: rename timer related helper to less confusing names
The msk socket uses to different timeout to track close related
events and retransmissions. The existing helpers do not indicate
clearly which timer they actually touch, making the related code
quite confusing.

Change the existing helpers name to avoid such confusion. No
functional change intended.

This patch is linked to the next one ("mptcp: fix dangling connection
hang-up"). The two patches are supposed to be backported together.

Cc: stable@vger.kernel.org # v5.11+
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-09-18 12:47:56 +01:00
Geliang Tang ed1ad86b85 mptcp: register default scheduler
This patch defines the default packet scheduler mptcp_sched_default.
Register it in mptcp_sched_init(), which is invoked in mptcp_proto_init().
Skip deleting this default scheduler in mptcp_unregister_scheduler().

Set msk->sched to the default scheduler when the input parameter of
mptcp_init_sched() is NULL.

Invoke mptcp_sched_default_get_subflow in get_send() and get_retrans()
if the defaut scheduler is set or msk->sched is NULL.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-10-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:19 -07:00
Geliang Tang 07336a87fe mptcp: add scheduler wrappers
This patch defines two packet scheduler wrappers mptcp_sched_get_send()
and mptcp_sched_get_retrans(), invoke get_subflow() of msk->sched in
them.

Set data->reinject to true in mptcp_sched_get_retrans(), set it false in
mptcp_sched_get_send().

If msk->sched is NULL, use default functions mptcp_subflow_get_send()
and mptcp_subflow_get_retrans() to send data.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-7-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:19 -07:00
Geliang Tang fce68b0308 mptcp: add scheduled in mptcp_subflow_context
This patch adds a new member scheduled in struct mptcp_subflow_context,
which will be set in the MPTCP scheduler context when the scheduler
picks this subflow to send data.

Add a new helper mptcp_subflow_set_scheduled() to set this flag using
WRITE_ONCE().

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-6-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:19 -07:00
Geliang Tang 1730b2b2c5 mptcp: add sched in mptcp_sock
This patch adds a new struct member sched in struct mptcp_sock.
And two helpers mptcp_init_sched() and mptcp_release_sched() to
init and release it.

Init it with the sysctl scheduler in mptcp_init_sock(), copy the
scheduler from the parent in mptcp_sk_clone(), and release it in
__mptcp_destroy_sock().

Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-5-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:19 -07:00
Geliang Tang e3b2870b6d mptcp: add a new sysctl scheduler
This patch adds a new sysctl, named scheduler, to support for selection
of different schedulers. Export mptcp_get_scheduler helper to get this
sysctl.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-4-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:18 -07:00
Geliang Tang 740ebe35bd mptcp: add struct mptcp_sched_ops
This patch defines struct mptcp_sched_ops, which has three struct members,
name, owner and list, and four function pointers: init(), release() and
get_subflow().

The scheduler function get_subflow() have a struct mptcp_sched_data
parameter, which contains a reinject flag for retrans or not, a subflows
number and a mptcp_subflow_context array.

Add the scheduler registering, unregistering and finding functions to add,
delete and find a packet scheduler on the global list mptcp_sched_list.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-3-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:18 -07:00
Geliang Tang ebc1e08f01 mptcp: drop last_snd and MPTCP_RESET_SCHEDULER
Since the burst check conditions have moved out of the function
mptcp_subflow_get_send(), it makes all msk->last_snd useless.
This patch drops them as well as the macro MPTCP_RESET_SCHEDULER.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-2-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:18 -07:00
Paolo Abeni 39880bd808 mptcp: get rid of msk->subflow
Such field is now unused just as a flag to control the first subflow
deletion at close() time. Introduce a new bit flag for that and finally
drop the mentioned field.

As an intended side effect, now the first subflow sock is not freed
before close() even for passive sockets. The msk has no open/active
subflows if the first one is closed and the subflow list is singular,
update accordingly the state check in mptcp_stream_accept().

Among other benefits, the subflow removal, reduces the amount of memory
used on the client side for each mptcp connection, allows passive sockets
to go through successful accept()/disconnect()/connect() and makes return
error code consistent for failing both passive and active sockets.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/290
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-08-14 07:06:14 +01:00
Paolo Abeni 3f326a821b mptcp: change the mpc check helper to return a sk
After the previous patch the __mptcp_nmpc_socket helper is used
only to ensure that the MPTCP socket is a suitable status - that
is, the mptcp capable handshake is not started yet.

Change the return value to the relevant subflow sock, to finally
remove the last references to first subflow socket in the MPTCP stack.

As a bonus, we can get rid of a few local variables in different
functions.

No functional change intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-08-14 07:06:14 +01:00
Jakub Kicinski 4d016ae42e Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:

drivers/net/ethernet/intel/igc/igc_main.c
  06b412589e ("igc: Add lock to safeguard global Qbv variables")
  d3750076d4 ("igc: Add TransmissionOverrun counter")

drivers/net/ethernet/microsoft/mana/mana_en.c
  a7dfeda6fd ("net: mana: Fix MANA VF unload when hardware is unresponsive")
  a9ca9f9cef ("page_pool: split types and declarations from page_pool.h")
  92272ec410 ("eth: add missing xdp.h includes in drivers")

net/mptcp/protocol.h
  511b90e392 ("mptcp: fix disconnect vs accept race")
  b8dc6d6ce9 ("mptcp: fix rcv buffer auto-tuning")

tools/testing/selftests/net/mptcp/mptcp_join.sh
  c8c101ae39 ("selftests: mptcp: join: fix 'implicit EP' test")
  03668c65d1 ("selftests: mptcp: join: rework detailed report")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-10 14:10:53 -07:00
Paolo Abeni 511b90e392 mptcp: fix disconnect vs accept race
Despite commit 0ad529d9fd ("mptcp: fix possible divide by zero in
recvmsg()"), the mptcp protocol is still prone to a race between
disconnect() (or shutdown) and accept.

The root cause is that the mentioned commit checks the msk-level
flag, but mptcp_stream_accept() does acquire the msk-level lock,
as it can rely directly on the first subflow lock.

As reported by Christoph than can lead to a race where an msk
socket is accepted after that mptcp_subflow_queue_clean() releases
the listener socket lock and just before it takes destructive
actions leading to the following splat:

BUG: kernel NULL pointer dereference, address: 0000000000000012
PGD 5a4ca067 P4D 5a4ca067 PUD 37d4c067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 2 PID: 10955 Comm: syz-executor.5 Not tainted 6.5.0-rc1-gdc7b257ee5dd #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
RIP: 0010:mptcp_stream_accept+0x1ee/0x2f0 include/net/inet_sock.h:330
Code: 0a 09 00 48 8b 1b 4c 39 e3 74 07 e8 bc 7c 7f fe eb a1 e8 b5 7c 7f fe 4c 8b 6c 24 08 eb 05 e8 a9 7c 7f fe 49 8b 85 d8 09 00 00 <0f> b6 40 12 88 44 24 07 0f b6 6c 24 07 bf 07 00 00 00 89 ee e8 89
RSP: 0018:ffffc90000d07dc0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888037e8d020 RCX: ffff88803b093300
RDX: 0000000000000000 RSI: ffffffff833822c5 RDI: ffffffff8333896a
RBP: 0000607f82031520 R08: ffff88803b093300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000003e83 R12: ffff888037e8d020
R13: ffff888037e8c680 R14: ffff888009af7900 R15: ffff888009af6880
FS:  00007fc26d708640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000012 CR3: 0000000066bc5001 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_accept+0x1ae/0x260 net/socket.c:1872
 __sys_accept4+0x9b/0x110 net/socket.c:1913
 __do_sys_accept4 net/socket.c:1954 [inline]
 __se_sys_accept4 net/socket.c:1951 [inline]
 __x64_sys_accept4+0x20/0x30 net/socket.c:1951
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Address the issue by temporary removing the pending request socket
from the accept queue, so that racing accept() can't touch them.

After depleting the msk - the ssk still exists, as plain TCP sockets,
re-insert them into the accept queue, so that later inet_csk_listen_stop()
will complete the tcp socket disposal.

Fixes: 2a6a870e44 ("mptcp: stops worker on unaccepted sockets at listener close")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/423
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Link: https://lore.kernel.org/r/20230803-upstream-net-20230803-misc-fixes-6-5-v1-4-6671b1ab11cc@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-04 18:26:27 -07:00
Paolo Abeni b8dc6d6ce9 mptcp: fix rcv buffer auto-tuning
The MPTCP code uses the assumption that the tcp_win_from_space() helper
does not use any TCP-specific field, and thus works correctly operating
on an MPTCP socket.

The commit dfa2f04833 ("tcp: get rid of sysctl_tcp_adv_win_scale")
broke such assumption, and as a consequence most MPTCP connections stall
on zero-window event due to auto-tuning changing the rcv buffer size
quite randomly.

Address the issue syncing again the MPTCP auto-tuning code with the TCP
one. To achieve that, factor out the windows size logic in socket
independent helpers, and reuse them in mptcp_rcv_space_adjust(). The
MPTCP level scaling_ratio is selected as the minimum one from the all
the subflows, as a worst-case estimate.

Fixes: dfa2f04833 ("tcp: get rid of sysctl_tcp_adv_win_scale")
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>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Link: https://lore.kernel.org/r/20230720-upstream-net-next-20230720-mptcp-fix-rcv-buffer-auto-tuning-v1-1-175ef12b8380@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-07-24 16:36:05 -07:00
Jakub Kicinski a7384f3918 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

Conflicts:

tools/testing/selftests/net/fcnal-test.sh
  d7a2fc1437 ("selftests: net: fcnal-test: check if FIPS mode is enabled")
  dd017c72dd ("selftests: fcnal: Test SO_DONTROUTE on TCP sockets.")
https://lore.kernel.org/all/5007b52c-dd16-dbf6-8d64-b9701bfa498b@tessares.net/
https://lore.kernel.org/all/20230619105427.4a0df9b3@canb.auug.org.au/

No adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-22 18:40:38 -07:00
Geliang Tang 528cb5f2a1 mptcp: pass addr to mptcp_pm_alloc_anno_list
Pass addr parameter to mptcp_pm_alloc_anno_list() instead of entry. We
can reduce the scope, e.g. in mptcp_pm_alloc_anno_list(), we only access
"entry->addr", we can then restrict to the pointer to "addr" then.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-21 22:45:58 -07:00
Paolo Abeni 6f06b4d4d1 mptcp: add subflow unique id
The user-space need to properly account the data received/sent by
individual subflows. When additional subflows are created and/or
closed during the MPTCP socket lifetime, the information currently
exposed via MPTCP_TCPINFO are not enough: subflows are identified only
by the sequential position inside the info dumps, and that will change
with the above mentioned events.

To solve the above problem, this patch introduces a new subflow
identifier that is unique inside the given MPTCP socket scope.

The initial subflow get the id 1 and the other subflows get incremental
values at join time.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/388
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-21 22:45:57 -07:00
Paolo Abeni 38967f424b mptcp: track some aggregate data counters
Currently there are no data transfer counters accounting for all
the subflows used by a given MPTCP socket. The user-space can compute
such figures aggregating the subflow info, but that is inaccurate
if any subflow is closed before the MPTCP socket itself.

Add the new counters in the MPTCP socket itself and expose them
via the existing diag and sockopt. While touching mptcp_diag_fill_info(),
acquire the relevant locks before fetching the msk data, to ensure
better data consistency

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/385
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-21 22:45:57 -07:00
Paolo Abeni b7535cfed2 mptcp: drop legacy code around RX EOF
Thanks to the previous patch -- "mptcp: consolidate fallback and non
fallback state machine" -- we can finally drop the "temporary hack"
used to detect rx eof.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-21 22:44:54 -07:00
Geliang Tang 6ba7ce8990 mptcp: unify pm set_flags interfaces
This patch unifies the three PM set_flags() interfaces:

mptcp_pm_nl_set_flags() in mptcp/pm_netlink.c for the in-kernel PM and
mptcp_userspace_pm_set_flags() in mptcp/pm_userspace.c for the
userspace PM.

They'll be switched in the common PM infterface mptcp_pm_set_flags() in
mptcp/pm.c based on whether token is NULL or not.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-10 00:05:59 -07:00
Geliang Tang f40be0db0b mptcp: unify pm get_flags_and_ifindex_by_id
This patch unifies the three PM get_flags_and_ifindex_by_id() interfaces:

mptcp_pm_nl_get_flags_and_ifindex_by_id() in mptcp/pm_netlink.c for the
in-kernel PM and mptcp_userspace_pm_get_flags_and_ifindex_by_id() in
mptcp/pm_userspace.c for the userspace PM.

They'll be switched in the common PM infterface
mptcp_pm_get_flags_and_ifindex_by_id() in mptcp/pm.c based on whether
mptcp_pm_is_userspace() or not.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-10 00:05:59 -07:00
Geliang Tang 9bbec87ecf mptcp: unify pm get_local_id interfaces
This patch unifies the three PM get_local_id() interfaces:

mptcp_pm_nl_get_local_id() in mptcp/pm_netlink.c for the in-kernel PM and
mptcp_userspace_pm_get_local_id() in mptcp/pm_userspace.c for the
userspace PM.

They'll be switched in the common PM infterface mptcp_pm_get_local_id()
in mptcp/pm.c based on whether mptcp_pm_is_userspace() or not.

Also put together the declarations of these three functions in protocol.h.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-10 00:05:59 -07:00
Geliang Tang dc886bce75 mptcp: export local_address
Rename local_address() with "mptcp_" prefix and export it in protocol.h.

This function will be re-used in the common PM code (pm.c) in the
following commit.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-10 00:05:59 -07:00
Geliang Tang 8b1c94da1e mptcp: only send RM_ADDR in nl_cmd_remove
The specifications from [1] about the "REMOVE" command say:

    Announce that an address has been lost to the peer

It was then only supposed to send a RM_ADDR and not trying to delete
associated subflows.

A new helper mptcp_pm_remove_addrs() is then introduced to do just
that, compared to mptcp_pm_remove_addrs_and_subflows() also removing
subflows.

To delete a subflow, the userspace daemon can use the "SUB_DESTROY"
command, see mptcp_nl_cmd_sf_destroy().

Fixes: d9a4594eda ("mptcp: netlink: Add MPTCP_PM_CMD_REMOVE")
Link: https://github.com/multipath-tcp/mptcp/blob/mptcp_v0.96/include/uapi/linux/mptcp.h [1]
Cc: stable@vger.kernel.org
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-06-05 15:15:57 +01:00
Paolo Abeni 7e8b88ec35 mptcp: consolidate passive msk socket initialization
When the msk socket is cloned at MPC handshake time, a few
fields are initialized in a racy way outside mptcp_sk_clone()
and the msk socket lock.

The above is due historical reasons: before commit a88d0092b2
("mptcp: simplify subflow_syn_recv_sock()") as the first subflow socket
carrying all the needed date was not available yet at msk creation
time

We can now refactor the code moving the missing initialization bit
under the socket lock, removing the init race and avoiding some
code duplication.

This will also simplify the next patch, as all msk->first write
access are now under the msk socket lock.

Fixes: 0397c6d85f ("mptcp: keep unaccepted MPC subflow into join list")
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-01 10:04:04 -07:00
Paolo Abeni 5b825727d0 mptcp: add annotations around msk->subflow accesses
The MPTCP can access the first subflow socket in a few spots
outside the socket lock scope. That is actually safe, as MPTCP
will delete the socket itself only after the msk sock close().

Still the such accesses causes a few KCSAN splats, as reported
by Christoph. Silence the harmless warning adding a few annotation
around the relevant accesses.

Fixes: 71ba088ce0 ("mptcp: cleanup accept and poll")
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/402
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-01 10:04:04 -07:00
Paolo Abeni 786fc12457 mptcp: fix connect timeout handling
Ondrej reported a functional issue WRT timeout handling on connect
with a nice reproducer.

The problem is that the current mptcp connect waits for both the
MPTCP socket level timeout, and the first subflow socket timeout.
The latter is not influenced/touched by the exposed setsockopt().

Overall the above makes the SO_SNDTIMEO a no-op on connect.

Since mptcp_connect is invoked via inet_stream_connect and the
latter properly handle the MPTCP level timeout, we can address the
issue making the nested subflow level connect always unblocking.

This also allow simplifying a bit the code, dropping an ugly hack
to handle the fastopen and custom proto_ops connect.

The issues predates the blamed commit below, but the current resolution
requires the infrastructure introduced there.

Fixes: 54f1944ed6 ("mptcp: factor out mptcp_connect()")
Reported-by: Ondrej Mosnacek <omosnace@redhat.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/399
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-01 10:04:04 -07:00
Jakub Kicinski 681c5b51dc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Adjacent changes:

net/mptcp/protocol.h
  63740448a3 ("mptcp: fix accept vs worker race")
  2a6a870e44 ("mptcp: stops worker on unaccepted sockets at listener close")
  ddb1a072f8 ("mptcp: move first subflow allocation at mpc access time")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-04-20 16:29:51 -07:00
Paolo Abeni 63740448a3 mptcp: fix accept vs worker race
The mptcp worker and mptcp_accept() can race, as reported by Christoph:

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 14351 at lib/refcount.c:25 refcount_warn_saturate+0x105/0x1b0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 14351 Comm: syz-executor.2 Not tainted 6.3.0-rc1-gde5e8fd0123c #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
RIP: 0010:refcount_warn_saturate+0x105/0x1b0 lib/refcount.c:25
Code: 02 31 ff 89 de e8 1b f0 a7 ff 84 db 0f 85 6e ff ff ff e8 3e f5 a7 ff 48 c7 c7 d8 c7 34 83 c6 05 6d 2d 0f 02 01 e8 cb 3d 90 ff <0f> 0b e9 4f ff ff ff e8 1f f5 a7 ff 0f b6 1d 54 2d 0f 02 31 ff 89
RSP: 0018:ffffc90000a47bf8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88802eae98c0 RSI: ffffffff81097d4f RDI: 0000000000000001
RBP: ffff88802e712180 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffff88802eaea148 R12: ffff88802e712100
R13: ffff88802e712a88 R14: ffff888005cb93a8 R15: ffff88802e712a88
FS:  0000000000000000(0000) GS:ffff88803ed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f277fd89120 CR3: 0000000035486002 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:775 [inline]
 __mptcp_close+0x4c6/0x4d0 net/mptcp/protocol.c:3051
 mptcp_close+0x24/0xe0 net/mptcp/protocol.c:3072
 inet_release+0x56/0xa0 net/ipv4/af_inet.c:429
 __sock_release+0x51/0xf0 net/socket.c:653
 sock_close+0x18/0x20 net/socket.c:1395
 __fput+0x113/0x430 fs/file_table.c:321
 task_work_run+0x96/0x100 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x4fc/0x10c0 kernel/exit.c:869
 do_group_exit+0x51/0xf0 kernel/exit.c:1019
 get_signal+0x12b0/0x1390 kernel/signal.c:2859
 arch_do_signal_or_restart+0x25/0x260 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x131/0x1a0 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x19/0x40 kernel/entry/common.c:296
 do_syscall_64+0x46/0x90 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fec4b4926a9
Code: Unable to access opcode bytes at 0x7fec4b49267f.
RSP: 002b:00007fec49f9dd78 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006bc058 RCX: 00007fec4b4926a9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006bc058
RBP: 00000000006bc050 R08: 00000000007df998 R09: 00000000007df998
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006bc05c
R13: fffffffffffffea8 R14: 000000000000000b R15: 000000000001fe40
 </TASK>

The root cause is that the worker can force fallback to TCP the first
mptcp subflow, actually deleting the unaccepted msk socket.

We can explicitly prevent the race delaying the unaccepted msk deletion
at listener shutdown time. In case the closed subflow is later accepted,
just drop the mptcp context and let the user-space deal with the
paired mptcp socket.

Fixes: b6985b9b82 ("mptcp: use the workqueue to destroy unaccepted sockets")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/375
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-19 09:08:37 +01:00
Paolo Abeni 2a6a870e44 mptcp: stops worker on unaccepted sockets at listener close
This is a partial revert of the blamed commit, with a relevant
change: mptcp_subflow_queue_clean() now just change the msk
socket status and stop the worker, so that the UaF issue addressed
by the blamed commit is not re-introduced.

The above prevents the mptcp worker from running concurrently with
inet_csk_listen_stop(), as such race would trigger a warning, as
reported by Christoph:

RSP: 002b:00007f784fe09cd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
WARNING: CPU: 0 PID: 25807 at net/ipv4/inet_connection_sock.c:1387 inet_csk_listen_stop+0x664/0x870 net/ipv4/inet_connection_sock.c:1387
RAX: ffffffffffffffda RBX: 00000000006bc050 RCX: 00007f7850afd6a9
RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000004
Modules linked in:
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006bc05c
R13: fffffffffffffea8 R14: 00000000006bc050 R15: 000000000001fe40

 </TASK>
CPU: 0 PID: 25807 Comm: syz-executor.7 Not tainted 6.2.0-g778e54711659 #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
RIP: 0010:inet_csk_listen_stop+0x664/0x870 net/ipv4/inet_connection_sock.c:1387
RAX: 0000000000000000 RBX: ffff888100dfbd40 RCX: 0000000000000000
RDX: ffff8881363aab80 RSI: ffffffff81c494f4 RDI: 0000000000000005
RBP: ffff888126dad080 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888100dfe040
R13: 0000000000000001 R14: 0000000000000000 R15: ffff888100dfbdd8
FS:  00007f7850a2c800(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32d26000 CR3: 000000012fdd8006 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 __tcp_close+0x5b2/0x620 net/ipv4/tcp.c:2875
 __mptcp_close_ssk+0x145/0x3d0 net/mptcp/protocol.c:2427
 mptcp_destroy_common+0x8a/0x1c0 net/mptcp/protocol.c:3277
 mptcp_destroy+0x41/0x60 net/mptcp/protocol.c:3304
 __mptcp_destroy_sock+0x56/0x140 net/mptcp/protocol.c:2965
 __mptcp_close+0x38f/0x4a0 net/mptcp/protocol.c:3057
 mptcp_close+0x24/0xe0 net/mptcp/protocol.c:3072
 inet_release+0x53/0xa0 net/ipv4/af_inet.c:429
 __sock_release+0x4e/0xf0 net/socket.c:651
 sock_close+0x15/0x20 net/socket.c:1393
 __fput+0xff/0x420 fs/file_table.c:321
 task_work_run+0x8b/0xe0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x113/0x120 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:296
 do_syscall_64+0x46/0x90 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f7850af70dc
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f7850af70dc
RDX: 00007f7850a2c800 RSI: 0000000000000002 RDI: 0000000000000003
RBP: 00000000006bd980 R08: 0000000000000000 R09: 00000000000018a0
R10: 00000000316338a4 R11: 0000000000000293 R12: 0000000000211e31
R13: 00000000006bc05c R14: 00007f785062c000 R15: 0000000000211af0

Fixes: 0a3f4f1f9c ("mptcp: fix UaF in listener shutdown")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/371
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-19 09:08:36 +01:00