diff options
| author | Paolo Abeni | 2020-12-09 12:03:31 +0100 |
|---|---|---|
| committer | David S. Miller | 2020-12-09 19:31:58 -0800 |
| commit | d7b1bfd0832c1d005f571203306b6c50e9805150 (patch) | |
| tree | 4835210f79ccb092abb8aff17daecae4f21acd38 /net | |
| parent | 0597d0f8e030d1a5e64708b0f3233209a8b5d39e (diff) | |
mptcp: be careful on subflows shutdown
When the workqueue disposes of the msk, the subflows can still
receive some data from the peer after __mptcp_close_ssk()
completes.
The above could trigger a race between the msk receive path and the
msk destruction. Acquiring the mptcp_data_lock() in __mptcp_destroy_sock()
will not save the day: the rx path could be reached even after msk
destruction completes.
Instead use the subflow 'disposable' flag to prevent entering
the msk receive path after __mptcp_close_ssk().
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mptcp/protocol.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 4e29dcf17ecd..2540d82742ac 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -701,6 +701,13 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) int sk_rbuf, ssk_rbuf; bool wake; + /* The peer can send data while we are shutting down this + * subflow at msk destruction time, but we must avoid enqueuing + * more data to the msk receive queue + */ + if (unlikely(subflow->disposable)) + return; + /* move_skbs_to_msk below can legitly clear the data_avail flag, * but we will need later to properly woke the reader, cache its * value @@ -2119,6 +2126,8 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, sock_orphan(ssk); } + subflow->disposable = 1; + /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops * the ssk has been already destroyed, we just need to release the * reference owned by msk; @@ -2126,8 +2135,7 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, if (!inet_csk(ssk)->icsk_ulp_ops) { kfree_rcu(subflow, rcu); } else { - /* otherwise ask tcp do dispose of ssk and subflow ctx */ - subflow->disposable = 1; + /* otherwise tcp will dispose of the ssk and subflow ctx */ __tcp_close(ssk, 0); /* close acquired an extra ref */ |