6.6-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
[ 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 --- net/mptcp/protocol.c | 6 ++---- net/mptcp/subflow.c | 13 +++++++++++-- 2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 2f794924ae5d4..55a90a7b7b517 100644 --- 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 15f456fb28977..ba739e7009221 100644 --- 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); }