Commit b6d69fc8 authored Nov 24, 2020 by Florian Westphal Committed by Jakub Kicinski Nov 25, 2020

mptcp: put reference in mptcp timeout timer



On close this timer might be scheduled. mptcp uses sk_reset_timer for
this, so the a reference on the mptcp socket is taken.

This causes a refcount leak which can for example be reproduced
with 'mp_join_server_v4.pkt' from the mptcp-packetdrill repo.

The leak has nothing to do with join requests, v1_mp_capable_bind_no_cs.pkt
works too when replacing the last ack mpcapable to v1 instead of v0.

unreferenced object 0xffff888109bba040 (size 2744):
  comm "packetdrill", [..]
  backtrace:
    [..] sk_prot_alloc.isra.0+0x2b/0xc0
    [..] sk_clone_lock+0x2f/0x740
    [..] mptcp_sk_clone+0x33/0x1a0
    [..] subflow_syn_recv_sock+0x2b1/0x690 [..]

Fixes: e16163b6 ("mptcp: refactor shutdown and close")
Cc: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20201124162446.11448-1-fw@strlen.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 4826d2c4

net/mptcp/protocol.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1710,6 +1710,7 @@ static void mptcp_timeout_timer(struct timer_list *t)
		struct sock *sk = from_timer(sk, t, sk_timer);

		mptcp_schedule_work(sk);
		sock_put(sk);
		}

		/* Find an idle subflow. Return NULL if there is unacked data at tcp

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