linux.git/net/mptcp/protocol.c, branch v5.12

mptcp: revert "mptcp: provide subflow aware release function"

2021-04-01T23:02:50+00:00

This change reverts commit ad98dd37051e ("mptcp: provide subflow aware
release function"). The latter introduced a deadlock spotted by
syzkaller and is not needed anymore after the previous commit.

Fixes: ad98dd37051e ("mptcp: provide subflow aware release function")
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: forbit mcast-related sockopt on MPTCP sockets

2021-04-01T23:02:50+00:00

Unrolling mcast state at msk dismantel time is bug prone, as
syzkaller reported:

======================================================
WARNING: possible circular locking dependency detected
5.11.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor905/8822 is trying to acquire lock:
ffffffff8d678fe8 (rtnl_mutex){+.+.}-{3:3}, at: ipv6_sock_mc_close+0xd7/0x110 net/ipv6/mcast.c:323

but task is already holding lock:
ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1600 [inline]
ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: mptcp6_release+0x57/0x130 net/mptcp/protocol.c:3507

which lock already depends on the new lock.

Instead we can simply forbit any mcast-related setsockopt

Fixes: 717e79c867ca5 ("mptcp: Add setsockopt()/getsockopt() socket operations")
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: fix bit MPTCP_PUSH_PENDING tests

2021-03-13T00:57:04+00:00

The MPTCP_PUSH_PENDING define is 6 and these tests should be testing if
BIT(6) is set.

Fixes: c2e6048fa1cf ("mptcp: fix race in release_cb")
Signed-off-by: Dan Carpenter 
Reviewed-by: Matthieu Baerts 
Signed-off-by: David S. Miller

mptcp: fix missing wakeup

2021-03-04T22:30:13+00:00

__mptcp_clean_una() can free write memory and should wake-up
user-space processes when needed.

When such function is invoked by the MPTCP receive path, the wakeup
is not needed, as the TCP stack will later trigger subflow_write_space
which will do the wakeup as needed.

Other __mptcp_clean_una() call sites need an additional wakeup check
Let's bundle the relevant code in a new helper and use it.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/165
Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks")
Fixes: 64b9cea7a0af ("mptcp: fix spurious retransmissions")
Tested-by: Matthieu Baerts 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: fix race in release_cb

2021-03-04T22:30:13+00:00

If we receive a MPTCP_PUSH_PENDING even from a subflow when
mptcp_release_cb() is serving the previous one, the latter
will be delayed up to the next release_sock(msk).

Address the issue implementing a test/serve loop for such
event.

Additionally rename the push helper to __mptcp_push_pending()
to be more consistent with the existing code.

Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks")
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: factor out __mptcp_retrans helper()

2021-03-04T22:30:13+00:00

Will simplify the following patch, no functional change
intended.

Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: reset 'first' and ack_hint on subflow close

2021-03-04T22:30:13+00:00

Just like with last_snd, we have to NULL 'first' on subflow close.

ack_hint isn't strictly required (its never dereferenced), but better to
clear this explicitly as well instead of making it an exception.

msk->first is dereferenced unconditionally at accept time, but
at that point the ssk is not on the conn_list yet -- this means
worker can't see it when iterating the conn_list.

Reported-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts 
Signed-off-by: Florian Westphal 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: dispose initial struct socket when its subflow is closed

2021-03-04T22:30:13+00:00

Christoph Paasch reported following crash:
dst_release underflow
WARNING: CPU: 0 PID: 1319 at net/core/dst.c:175 dst_release+0xc1/0xd0 net/core/dst.c:175
CPU: 0 PID: 1319 Comm: syz-executor217 Not tainted 5.11.0-rc6af8e85128b4d0d24083c5cac646e891227052e0c #70
Call Trace:
 rt_cache_route+0x12e/0x140 net/ipv4/route.c:1503
 rt_set_nexthop.constprop.0+0x1fc/0x590 net/ipv4/route.c:1612
 __mkroute_output net/ipv4/route.c:2484 [inline]
...

The worker leaves msk->subflow alone even when it
happened to close the subflow ssk associated with it.

Fixes: 866f26f2a9c33b ("mptcp: always graft subflow socket to parent")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/157
Reported-by: Christoph Paasch 
Suggested-by: Paolo Abeni 
Acked-by: Paolo Abeni 
Signed-off-by: Florian Westphal 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: fix memory accounting on allocation error

2021-03-04T22:30:13+00:00

In case of memory pressure the MPTCP xmit path keeps
at most a single skb in the tx cache, eventually freeing
additional ones.

The associated counter for forward memory is not update
accordingly, and that causes the following splat:

WARNING: CPU: 0 PID: 12 at net/core/stream.c:208 sk_stream_kill_queues+0x3ca/0x530 net/core/stream.c:208
Modules linked in:
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.11.0-rc2 #59
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: events mptcp_worker
RIP: 0010:sk_stream_kill_queues+0x3ca/0x530 net/core/stream.c:208
Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 63 01 00 00 8b ab 00 01 00 00 e9 60 ff ff ff e8 2f 24 d3 fe 0f 0b eb 97 e8 26 24 d3 fe <0f> 0b eb a0 e8 1d 24 d3 fe 0f 0b e9 a5 fe ff ff 4c 89 e7 e8 0e d0
RSP: 0018:ffffc900000c7bc8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88810030ac40 RSI: ffffffff8262ca4a RDI: 0000000000000003
RBP: 0000000000000d00 R08: 0000000000000000 R09: ffffffff85095aa7
R10: ffffffff8262c9ea R11: 0000000000000001 R12: ffff888108908100
R13: ffffffff85095aa0 R14: ffffc900000c7c48 R15: 1ffff92000018f85
FS:  0000000000000000(0000) GS:ffff88811b200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa7444baef8 CR3: 0000000035ee9005 CR4: 0000000000170ef0
Call Trace:
 __mptcp_destroy_sock+0x4a7/0x6c0 net/mptcp/protocol.c:2547
 mptcp_worker+0x7dd/0x1610 net/mptcp/protocol.c:2272
 process_one_work+0x896/0x1170 kernel/workqueue.c:2275
 worker_thread+0x605/0x1350 kernel/workqueue.c:2421
 kthread+0x344/0x410 kernel/kthread.c:292
 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296

At close time, as reported by syzkaller/Christoph.

This change address the issue properly updating the fwd
allocated memory counter in the error path.

Reported-by: Christoph Paasch 
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/136
Fixes: 724cfd2ee8aa ("mptcp: allocate TX skbs in msk context")
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller

mptcp: reset last_snd on subflow close

2021-03-04T22:30:13+00:00

Send logic caches last active subflow in the msk, so it needs to be
cleared when the cached subflow is closed.

Fixes: d5f49190def61c ("mptcp: allow picking different xmit subflows")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/155
Reported-by: Christoph Paasch 
Acked-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts 
Signed-off-by: Florian Westphal 
Signed-off-by: Mat Martineau 
Signed-off-by: David S. Miller