mptcp: fix more tx path fields initialization

[ Upstream commit 3f83d8a77eeeb47011b990fd766a421ee64f1d73 ]

The 'msk->write_seq' and 'msk->snd_nxt' are always updated under
the msk socket lock, except at MPC handshake completiont time.

Builds-up on the previous commit to move such init under the relevant
lock.

There are no known problems caused by the potential race, the
primary goal is consistency.

Fixes: 6d0060f600ad ("mptcp: Write MPTCP DSS headers to outgoing data packets")
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>
Stable-dep-of: e4a0fa47e816 ("mptcp: corner case locking for rx path fields initialization")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 2f794924ae5d4eadaba0c325ea0ca77ae43fb394..55a90a7b7b51727e454d20d3a8087a4319710c1a 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3525,10 +3525,8 @@ void mptcp_finish_connect(struct sock *ssk)
         * accessing the field below
         */
        WRITE_ONCE(msk->local_key, subflow->local_key);
-       WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
-       WRITE_ONCE(msk->snd_nxt, msk->write_seq);
-       WRITE_ONCE(msk->snd_una, msk->write_seq);
-       WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
+       WRITE_ONCE(msk->snd_una, subflow->idsn + 1);
+       WRITE_ONCE(msk->wnd_end, subflow->idsn + 1 + tcp_sk(ssk)->snd_wnd);
 
        mptcp_pm_new_connection(msk, ssk, 0);
 }

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 15f456fb28977a2858c8ade9001f686f6755b7b8..ba739e700922123f9af3196a77e2c7ef1ba64ddf 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -421,12 +421,21 @@ static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct soc
 
 void __mptcp_sync_state(struct sock *sk, int state)
 {
+       struct mptcp_subflow_context *subflow;
        struct mptcp_sock *msk = mptcp_sk(sk);
+       struct sock *ssk = msk->first;
 
-       __mptcp_propagate_sndbuf(sk, msk->first);
+       subflow = mptcp_subflow_ctx(ssk);
+       __mptcp_propagate_sndbuf(sk, ssk);
        if (!msk->rcvspace_init)
-               mptcp_rcv_space_init(msk, msk->first);
+               mptcp_rcv_space_init(msk, ssk);
+
        if (sk->sk_state == TCP_SYN_SENT) {
+               /* subflow->idsn is always available is TCP_SYN_SENT state,
+                * even for the FASTOPEN scenarios
+                */
+               WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
+               WRITE_ONCE(msk->snd_nxt, msk->write_seq);
                mptcp_set_state(sk, state);
                sk->sk_state_change(sk);
        }