linux.git/net/mptcp/protocol.c, branch v6.14

mptcp: handle fastopen disconnect correctly

2025-01-27T23:07:02+00:00

Syzbot was able to trigger a data stream corruption:

  WARNING: CPU: 0 PID: 9846 at net/mptcp/protocol.c:1024 __mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024
  Modules linked in:
  CPU: 0 UID: 0 PID: 9846 Comm: syz-executor351 Not tainted 6.13.0-rc2-syzkaller-00059-g00a5acdbf398 #0
  Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
  RIP: 0010:__mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024
  Code: fa ff ff 48 8b 4c 24 18 80 e1 07 fe c1 38 c1 0f 8c 8e fa ff ff 48 8b 7c 24 18 e8 e0 db 54 f6 e9 7f fa ff ff e8 e6 80 ee f5 90 <0f> 0b 90 4c 8b 6c 24 40 4d 89 f4 e9 04 f5 ff ff 44 89 f1 80 e1 07
  RSP: 0018:ffffc9000c0cf400 EFLAGS: 00010293
  RAX: ffffffff8bb0dd5a RBX: ffff888033f5d230 RCX: ffff888059ce8000
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
  RBP: ffffc9000c0cf518 R08: ffffffff8bb0d1dd R09: 1ffff110170c8928
  R10: dffffc0000000000 R11: ffffed10170c8929 R12: 0000000000000000
  R13: ffff888033f5d220 R14: dffffc0000000000 R15: ffff8880592b8000
  FS:  00007f6e866496c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f6e86f491a0 CR3: 00000000310e6000 CR4: 00000000003526f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   
   __mptcp_clean_una_wakeup+0x7f/0x2d0 net/mptcp/protocol.c:1074
   mptcp_release_cb+0x7cb/0xb30 net/mptcp/protocol.c:3493
   release_sock+0x1aa/0x1f0 net/core/sock.c:3640
   inet_wait_for_connect net/ipv4/af_inet.c:609 [inline]
   __inet_stream_connect+0x8bd/0xf30 net/ipv4/af_inet.c:703
   mptcp_sendmsg_fastopen+0x2a2/0x530 net/mptcp/protocol.c:1755
   mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1830
   sock_sendmsg_nosec net/socket.c:711 [inline]
   __sock_sendmsg+0x1a6/0x270 net/socket.c:726
   ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583
   ___sys_sendmsg net/socket.c:2637 [inline]
   __sys_sendmsg+0x269/0x350 net/socket.c:2669
   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: 0033:0x7f6e86ebfe69
  Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 1f 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 b0 ff ff ff f7 d8 64 89 01 48
  RSP: 002b:00007f6e86649168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
  RAX: ffffffffffffffda RBX: 00007f6e86f491b8 RCX: 00007f6e86ebfe69
  RDX: 0000000030004001 RSI: 0000000020000080 RDI: 0000000000000003
  RBP: 00007f6e86f491b0 R08: 00007f6e866496c0 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6e86f491bc
  R13: 000000000000006e R14: 00007ffe445d9420 R15: 00007ffe445d9508
   

The root cause is the bad handling of disconnect() generated internally
by the MPTCP protocol in case of connect FASTOPEN errors.

Address the issue increasing the socket disconnect counter even on such
a case, to allow other threads waiting on the same socket lock to
properly error out.

Fixes: c2b2ae3925b6 ("mptcp: handle correctly disconnect() failures")
Cc: stable@vger.kernel.org
Reported-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/67605870.050a0220.37aaf.0137.GAE@google.com
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/537
Tested-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20250123-net-mptcp-syzbot-issues-v1-3-af73258a726f@kernel.org
Signed-off-by: Jakub Kicinski

net: remove init_dummy_netdev()

2025-01-14T03:06:51+00:00

init_dummy_netdev() can initialize statically declared or embedded
net_devices. Such netdevs did not come from alloc_netdev_mqs().
After recent work by Breno, there are the only two cases where
we have do that.

Switch those cases to alloc_netdev_mqs() and delete init_dummy_netdev().
Dealing with static netdevs is not worth the maintenance burden.

Reviewed-by: Alexander Lobakin 
Reviewed-by: Matthieu Baerts (NGI0) 
Reviewed-by: Joe Damato 
Link: https://patch.msgid.link/20250113003456.3904110-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: prevent excessive coalescing on receive

2025-01-03T02:44:03+00:00

Currently the skb size after coalescing is only limited by the skb
layout (the skb must not carry frag_list). A single coalesced skb
covering several MSS can potentially fill completely the receive
buffer. In such a case, the snd win will zero until the receive buffer
will be empty again, affecting tput badly.

Fixes: 8268ed4c9d19 ("mptcp: introduce and use mptcp_try_coalesce()")
Cc: stable@vger.kernel.org # please delay 2 weeks after 6.13-final release
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20241230-net-mptcp-rbuf-fixes-v1-3-8608af434ceb@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: don't always assume copied data in mptcp_cleanup_rbuf()

2025-01-03T02:44:03+00:00

Under some corner cases the MPTCP protocol can end-up invoking
mptcp_cleanup_rbuf() when no data has been copied, but such helper
assumes the opposite condition.

Explicitly drop such assumption and performs the costly call only
when strictly needed - before releasing the msk socket lock.

Fixes: fd8976790a6c ("mptcp: be careful on MPTCP-level ack.")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20241230-net-mptcp-rbuf-fixes-v1-2-8608af434ceb@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: fix recvbuffer adjust on sleeping rcvmsg

2025-01-03T02:44:03+00:00

If the recvmsg() blocks after receiving some data - i.e. due to
SO_RCVLOWAT - the MPTCP code will attempt multiple times to
adjust the receive buffer size, wrongly accounting every time the
cumulative of received data - instead of accounting only for the
delta.

Address the issue moving mptcp_rcv_space_adjust just after the
data reception and passing it only the just received bytes.

This also removes an unneeded difference between the TCP and MPTCP
RX code path implementation.

Fixes: 581302298524 ("mptcp: error out earlier on disconnect")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20241230-net-mptcp-rbuf-fixes-v1-1-8608af434ceb@kernel.org
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-11-14T19:29:15+00:00

Cross-merge networking fixes after downstream PR (net-6.12-rc8).

Conflicts:

tools/testing/selftests/net/.gitignore
  252e01e68241 ("selftests: net: add netlink-dumps to .gitignore")
  be43a6b23829 ("selftests: ncdevmem: Move ncdevmem under drivers/net/hw")
https://lore.kernel.org/all/20241113122359.1b95180a@canb.auug.org.au/

drivers/net/phy/phylink.c
  671154f174e0 ("net: phylink: ensure PHY momentary link-fails are handled")
  7530ea26c810 ("net: phylink: remove "using_mac_select_pcs"")

Adjacent changes:

drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c
  5b366eae7193 ("stmmac: dwmac-intel-plat: fix call balance of tx_clk handling routines")
  e96321fad3ad ("net: ethernet: Switch back to struct platform_driver::remove()")

Signed-off-by: Jakub Kicinski

mptcp: fix possible integer overflow in mptcp_reset_tout_timer

2024-11-13T02:11:23+00:00

In 'mptcp_reset_tout_timer', promote 'probe_timestamp' to unsigned long
to avoid possible integer overflow. Compile tested only.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Dmitry Kandybka 
Link: https://patch.msgid.link/20241107103657.1560536-1-d.kandybka@gmail.com
Signed-off-by: Jakub Kicinski

mptcp: cope racing subflow creation in mptcp_rcv_space_adjust

2024-11-12T03:06:34+00:00

Additional active subflows - i.e. created by the in kernel path
manager - are included into the subflow list before starting the
3whs.

A racing recvmsg() spooling data received on an already established
subflow would unconditionally call tcp_cleanup_rbuf() on all the
current subflows, potentially hitting a divide by zero error on
the newly created ones.

Explicitly check that the subflow is in a suitable state before
invoking tcp_cleanup_rbuf().

Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows")
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/02374660836e1b52afc91966b7535c8c5f7bafb0.1731060874.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski

mptcp: error out earlier on disconnect

2024-11-12T03:06:34+00:00

Eric reported a division by zero splat in the MPTCP protocol:

Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 6094 Comm: syz-executor317 Not tainted
6.12.0-rc5-syzkaller-00291-g05b92660cdfe #0
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 09/13/2024
RIP: 0010:__tcp_select_window+0x5b4/0x1310 net/ipv4/tcp_output.c:3163
Code: f6 44 01 e3 89 df e8 9b 75 09 f8 44 39 f3 0f 8d 11 ff ff ff e8
0d 74 09 f8 45 89 f4 e9 04 ff ff ff e8 00 74 09 f8 44 89 f0 99  7c
24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 e8 73 09 f8 48 89
RSP: 0018:ffffc900041f7930 EFLAGS: 00010293
RAX: 0000000000017e67 RBX: 0000000000017e67 RCX: ffffffff8983314b
RDX: 0000000000000000 RSI: ffffffff898331b0 RDI: 0000000000000004
RBP: 00000000005d6000 R08: 0000000000000004 R09: 0000000000017e67
R10: 0000000000003e80 R11: 0000000000000000 R12: 0000000000003e80
R13: ffff888031d9b440 R14: 0000000000017e67 R15: 00000000002eb000
FS: 00007feb5d7f16c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feb5d8adbb8 CR3: 0000000074e4c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:

__tcp_cleanup_rbuf+0x3e7/0x4b0 net/ipv4/tcp.c:1493
mptcp_rcv_space_adjust net/mptcp/protocol.c:2085 [inline]
mptcp_recvmsg+0x2156/0x2600 net/mptcp/protocol.c:2289
inet_recvmsg+0x469/0x6a0 net/ipv4/af_inet.c:885
sock_recvmsg_nosec net/socket.c:1051 [inline]
sock_recvmsg+0x1b2/0x250 net/socket.c:1073
__sys_recvfrom+0x1a5/0x2e0 net/socket.c:2265
__do_sys_recvfrom net/socket.c:2283 [inline]
__se_sys_recvfrom net/socket.c:2279 [inline]
__x64_sys_recvfrom+0xe0/0x1c0 net/socket.c:2279
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feb5d857559
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feb5d7f1208 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 00007feb5d8e1318 RCX: 00007feb5d857559
RDX: 000000800000000e RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007feb5d8e1310 R08: 0000000000000000 R09: ffffffff81000000
R10: 0000000000000100 R11: 0000000000000246 R12: 00007feb5d8e131c
R13: 00007feb5d8ae074 R14: 000000800000000e R15: 00000000fffffdef

and provided a nice reproducer.

The root cause is the current bad handling of racing disconnect.
After the blamed commit below, sk_wait_data() can return (with
error) with the underlying socket disconnected and a zero rcv_mss.

Catch the error and return without performing any additional
operations on the current socket.

Reported-by: Eric Dumazet 
Fixes: 419ce133ab92 ("tcp: allow again tcp_disconnect() when threads are waiting")
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/8c82ecf71662ecbc47bf390f9905de70884c9f2d.1731060874.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-11-01T01:10:07+00:00

Cross-merge networking fixes after downstream PR (net-6.12-rc6).

Conflicts:

drivers/net/wireless/intel/iwlwifi/mvm/mld-mac80211.c
  cbe84e9ad5e2 ("wifi: iwlwifi: mvm: really send iwl_txpower_constraints_cmd")
  188a1bf89432 ("wifi: mac80211: re-order assigning channel in activate links")
https://lore.kernel.org/all/20241028123621.7bbb131b@canb.auug.org.au/

net/mac80211/cfg.c
  c4382d5ca1af ("wifi: mac80211: update the right link for tx power")
  8dd0498983ee ("wifi: mac80211: Fix setting txpower with emulate_chanctx")

drivers/net/ethernet/intel/ice/ice_ptp_hw.h
  6e58c3310622 ("ice: fix crash on probe for DPLL enabled E810 LOM")
  e4291b64e118 ("ice: Align E810T GPIO to other products")
  ebb2693f8fbd ("ice: Read SDP section from NVM for pin definitions")
  ac532f4f4251 ("ice: Cleanup unused declarations")
https://lore.kernel.org/all/20241030120524.1ee1af18@canb.auug.org.au/

No adjacent changes.

Signed-off-by: Jakub Kicinski