Commit 1bba3f21 authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: do not fallback when OoO is present 

In case of DSS corruption, the MPTCP protocol tries to avoid the subflow
reset if fallback is possible. Such corruptions happen in the receive
path; to ensure fallback is possible the stack additionally needs to
check for OoO data, otherwise the fallback will break the data stream.

Fixes: e32d262c ("mptcp: handle consistently DSS corruption")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/598


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-4-806d3781c95f@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 17393fa7

net/mptcp/protocol.c

+7 −0
Original line number Diff line number Diff line
@@ -76,6 +76,13 @@ bool __mptcp_try_fallback(struct mptcp_sock *msk, int fb_mib) 
	if (__mptcp_check_fallback(msk))

		return true;



	/* The caller possibly is not holding the msk socket lock, but

	 * in the fallback case only the current subflow is touching

	 * the OoO queue.

	 */

	if (!RB_EMPTY_ROOT(&msk->out_of_order_queue))

		return false;



	spin_lock_bh(&msk->fallback_lock);

	if (!msk->allow_infinite_fallback) {

		spin_unlock_bh(&msk->fallback_lock);